bluuebunny/crossref_metadata_2025 huggingface dataset:
Ubiquitin–proteasome pathway mediates degradation of APH‐1
Authors: He Guiqiong , Qing Hong , Cai Fang , Kwok Clement , Xu Huaxi , Yu Gang , Bernstein Alan , Song Weihong
Published: October 2006

γ‐Secretase catalyzes intramembraneous proteolysis of several type I transmembrane proteins, including β‐amyloid precursor protein (APP), to generate amyloid β protein (Aβ), a key player in the pathogenesis of Alzheimer's disease (AD). The critical components of the γ‐secretase complex include presenilin (PS), nicastrin (NCT), presenilin enhancer‐2 (PEN‐2) and anterior pharynx defective‐1 (APH‐1). Abnormalities of the ubiquitin–proteasome pathway have been implicated in the pathogenesis of AD; while PS and PEN‐2 turnover is regulated by this pathway, it is unknown whether the ubiquitin–proteasome pathway is also involved in the degradation of APH‐1 protein. In this study, we found that the expression of endogenous and exogenous APH‐1 significantly increased in cells treated with proteasome‐specific inhibitors. The effect of the proteasome inhibitors on APH‐1 was dose‐ and time‐dependent. APH‐1 protein was ubiquitinated. Pulse‐chase metabolic labeling experiments showed that the degradation of newly synthesized radiolabeled APH‐1 proteins was inhibited by lactacystin. Disruption of the PS1 and PS2 genes did not affect the degradation of APH‐1 by the ubiquitin–proteasome pathway. Furthermore, over‐expression of APH‐1 and inhibition of proteasomal APH‐1 degradation facilitated γ‐secretase cleavage of APP to generate Aβ. These results demonstrate that the degradation of APH‐1 protein is mediated by the ubiquitin–proteasome pathway.
Regulation of neurotrophin‐3 gene transcription by Sp3 and Sp4 in neurons
Authors: Ishimaru Naoki , Tabuchi Akiko , Hara Daichi , Hayashi Hiroyuki , Sugimoto Takayuki , Yasuhara Masahiro , Shiota Jun , Tsuda Masaaki
Published: October 2006

Neurotrophin‐3 (NT‐3), a neurotrophin member, plays crucial roles in neuronal development, function and plasticity. Previous studies have demonstrated that NT‐3 gene transcription is driven by alternative promoters A and B, located upstream of exons 1A (EIA) and 1B (EIB), respectively. However, the transcription factors and DNA elements that drive NT‐3 gene transcription remain to be identified. Here, we analysed the promoter region of the NT‐3 gene and found that an NT‐3 transcript containing EIB is predominantly expressed in cortical neurons which preferentially utilize promoter B, and two tandemly repeated GC‐boxes, located between −100 and −60 base pairs within promoter B, are required for the transcription. Electrophoretic mobility shift and chromatin immunoprecipitation assays revealed that both specificity protein (Sp)3 and Sp4 were able to bind to the Sp1 binding sequences within the GC boxes. Expression of dominant‐negative Sp3 and Sp4 small interfering RNA in cortical neurons reduced the activity of the NT‐3 gene promoter. Over‐expression of Sp1 family members, especially Sp4, resulted in an increase of the NT‐3 gene promoter. These findings indicate that the NT‐3 gene is a target gene for Sp4 that is abundantly expressed in the brain.
The secret life of languages. Origin‐specific differences in L1/L2 acquisition by immigrant children
Authors: Brizić Katharina
Published: October 2006

Focussing on Turkish immigrant children, in whom weak L1/L2 performance has repeatedly been reported, the article aims at providing explanations for origin‐specific differences between the L1/L2 acquisition of immigrant children from Turkey and former Yugoslavia living in Austria. The discussion focuses on the countries of origin, taking into account particularly their policies on (minority) language(s) and education. The resulting new explanatory model integrates approaches from socio‐ and psycholinguistics as well as language attrition studies, sociology and pedagogy. This model is applied to a sample of 60 primary school immigrant children from the two countries of origin. Because of their interdisciplinary and specifically language‐political character, the results may have considerable implications for further research as well as educational and political practice.
Evolving concepts and moving targets: communicative competence and the mediation of communication
Authors: Kenning Marie‐Madeleine
Published: October 2006

This article introduces a new dimension to the debate over the re‐conceptualisation of communicative competence and its implications for language pedagogy. Approaching the issue from a technological rather than a socio‐political perspective, it begins by tracing the marginalisation of technological matters in descriptions of communicative competence. Next, work on the effect of the media on communication is reviewed. This leads to the deconstruction of communication into a set of five variables that are examined in detail, together with their impact on participants. It is shown how variation along any one of the dimensions may affect the ability of less proficient language users to participate, and may cause variations along another. The article ends with a critical evaluation of the relevance of the framework to different contexts and some suggestions for further research.
Word class influence on word association test results1
Authors: Nissen Henriette Bagger , Henriksen Birgit
Published: October 2006

The aim of this article is to investigate the influence of word class on word association test results in both the L1 and L2. The data clearly suggest that word class type affects test results: nouns elicit a higher proportion of paradigmatic responses than verbs and adjectives. The influence of word class on test results is discussed in terms of the acquisition and semantic organisation of nouns, verbs and adjectives. However, results also show a surprising majority of syntagmatic responses in the L1 test. These results lead to a critical discussion of the concept of the syntagmatic–paradigmatic shift, which in the light of the test results in this study is seriously challenged. Theoretical and pedagogical implications for lexical network structure are discussed.
Revisiting Wilkins' Notional Syllabuses
Authors: Johnson Keith
Published: October 2006

One of the innovations that we have recently introduced in our reviews section is to include reviews of books that were published some time ago. The aim of the ‘classics’ reviews is to indicate how far these older works are still relevant to current thinking, how far we have or have not moved on, and generally to serve as an occasion for a critical reappraisal. The intention is to publish these reviews on a significant anniversary of the original publication, and as 2006 is the 30th anniversary of David Wilkins's Notional Syllabuses, we have asked Keith Johnson to launch the series with a review of this book.
Elevated metabolic costs while resting on water in a surface feeder: the Black‐legged Kittiwake Rissa tridactyla
Authors: HUMPHREYS ELIZABETH M. , WANLESS SARAH , BRYANT DAVID M.
Published: October 2006

Measurements of the energy costs of individual behaviours provide insights into how animals trade‐off resource allocation and energy acquisition decisions. The energetic costs while resting on water are poorly known for seabirds but could comprise a substantial proportion of their daily energy expenditure. We measured the cost of resting on water in Black‐legged Kittiwakes Rissa tridactyla, a species which does not fly during the night and for which estimating energy expenditure while resting on the water is therefore important. Their resting metabolic rate on water at 12.5 °C was at least 40% higher compared with resting at the same temperature in air. This indicates that, at comparable temperatures, metabolic costs are elevated for birds resting at sea compared with on land. We argue that Kittiwakes meet much of this extra thermoregulatory demand by dedicated metabolic activity. During the winter months, their costs are likely to be even higher owing to lower sea temperatures. Accordingly, we suggest that migration to milder latitudes, following breeding, will provide enhanced benefits, particularly to seabirds such as Kittiwakes which rest on the sea surface during darkness.
Seasonal resource tracking by Amazonian hummingbirds
Authors: COTTON PETER A.
Published: October 2006

Many ecological theories predict a close match between food resources and the number and diversity of consumers but comparatively few empirical studies have simultaneously quantified seasonal variation in an entire assemblage and its resource base. Hummingbirds provide an excellent model system to examine this relationship because their primary food resource is conspicuous and easily quantified. Over a 2‐year period I used mist‐netting and direct observation of birds feeding at flowering plants to record the abundance of 16 species of hummingbird in lowland Amazonian rainforest. Although there was very little annual variation in temperature and daylength, both rainfall and river level showed significant seasonal variation. At the study site this resulted in an annual flood lasting for over 5 months, inundating much of the area to a depth of 2 m. I recorded marked seasonal patterns in flowering phenology and arthropod abundance, which correlated with river level and rainfall, respectively. In turn, these seasonal fluctuations in resource abundance correlated very closely with variation in hummingbird species richness, hummingbird abundance and the total biomass of hummingbirds in the assemblage. This study is the first to demonstrate tracking of seasonal resource variation in equatorial rainforest and provides evidence that hummingbirds are sensitive to resource availability at spatial and temporal scales much greater than previously documented.
Ownership Concentration in Privatized Firms: The Role of Disclosure Standards, Auditor Choice, and Auditing Infrastructure
Authors: GUEDHAMI OMRANE , PITTMAN JEFFREY A.
Published: October 2006

We rely on a unique data set to estimate the impact of disclosure standards and auditor‐related characteristics on ownership concentration in 190 privatized firms from 31 countries. Accounting transparency can help alleviate the agency conflict between minority investors and controlling shareholders, which is evident in the extent of ownership concentration, since the expropriation of corporate resources hinges on these private benefits remaining hidden. After controlling for other country‐level and firm‐level determinants, we find weak (no) evidence that extensive disclosure standards (auditor choice) reduce ownership concentration. In contrast, we report strong, robust evidence that ownership concentration is lower in countries with securities laws that specify a lower burden of proof in civil and criminal litigation against auditors, consistent with Ball's [2001] predictions. Collectively, our research implies that minority investors worldwide value legal institutions that discipline auditors in the event of financial reporting failure over both the presence of a Big 5 auditor and better disclosure standards. Re‐estimating our regressions on a broad sample of western European public firms provides similar evidence on all of our predictions.
Models and Experiments for Sodium Evaporation From Sodium‐Containing Silicate Melts
Authors: Van Limpt Hans , Beerkens Ruud , Verheijen Oscar
Published: October 2006

Universal simulation models based on (a) validated mass transfer relations and (b) thermodynamic modeling procedures for glass melts are developed to predict the evaporation rates of volatile species from a large range of glass melt compositions. Depending on the glass composition, temperature of the surface of the melt, local composition of the atmosphere, exposure time of a melt layer to the combustion atmosphere, and local gas velocities above the glass melt surface, the evaporation rates of volatile species can be estimated. Laboratory‐scale transpiration evaporation experiments have been used to study evaporation kinetics, to derive mass transfer relations, as well as to validate the sodium evaporation modeling results for sodium‐silicate melts as well as for soda‐lime‐silicate melts. In these investigations, the molten sodium‐silicate and soda‐lime‐silicate melts are exposed to atmospheres of flowing gases with controlled composition and gas flow rates. In a humid atmosphere for example, sodium mainly evaporates as NaOH. From the measured NaOH evaporation rates and the mass transfer relations, the NaOH vapor pressures in equilibrium with the molten glass at prevalent temperature and furnace atmosphere composition were derived. The NaOH vapor pressures are assumed to be in equilibrium with the glass melt composition at the surface of the melt. During the evaporation test, the Na2O surface composition will change due to depletion. This leads to equilibrium vapor pressures decreasing with time, reflecting the changing chemical activity at the glass melt surface. The results of evaporation tests for sodium‐disilicate and soda‐lime‐silicate glass melts are shown. Chemical activities derived from these measurements are compared with the results of thermodynamic modeling, using a method based on a glass melt from ideal mixtures of associate (stoichiometric) species of structural compounds with known thermodynamic properties.
Effects of Thermal Annealing on Formation of Micro Porous Titanium Oxide by the Sol–Gel Method
Authors: Koyama Hiroshi , Fujimoto Masayuki , Ohno Tomoya , Suzuki Hisao , Tanaka Junzo
Published: October 2006

We investigated the structural and optical properties of microporous titanium oxide (TiO2) fabricated by the sol–gel method using templates of colloidal crystals with polystyrene spheres when the annealing temperature was changed between 600° and 1000°C. From X‐ray diffraction patterns and SEM images, the rutile TiO2 annealed at a high temperature did not form periodic porous bodies, while the anatase TiO2 annealed at lower than 800°C formed periodic porous bodies. The porous TiO2 obtained acts as an air‐sphere/TiO2 photonic crystal with an FCC structure. It is suggested that TiO2 sol annealed at a lower temperature do not lead to phase transition from the anatase phase to the rutile phase to obtain the air‐sphere/TiO2 photonic crystal by the sol–gel method using templates of colloidal crystals.
Effects of Zinc Substitution on Crystal Structure and Microwave Dielectric Properties of CaLa4Ti5O17 Ceramics
Authors: Zhao Fei , Yue Zhenxing , Gui Zhilun , Li Longtu
Published: October 2006

Zinc‐substituted CaLa4Ti5O17 microwave dielectric ceramics with the composition of Ca1−xZnxLa4Ti5O17 (x=0–1) were prepared by a solid‐state reaction method. The effects of zinc substitution on sintering behavior, crystal structure, and microwave dielectric properties of CaLa4Ti5O17 ceramics were investigated. Zinc substitution can effectively lower the sintering temperature of CaLa4Ti5O17 ceramics from 1500° to 1100°C. X‐ray diffraction and Raman spectra analysis reveal that with increasing zinc content, the n value of the AnBnO3n+2 structures changed and distinct compounds formed. With increasing Zn2+ content, the perovskite‐slabs decreased from 5‐[BO6] to 4.5‐[BO6] in the range of 0.13≤x≤0.2, and then collapsed to 4‐[BO6] at about x=0.6, with Zn2TiO4 as the secondary phase. The microwave dielectric properties of the sintered ceramics vary with the Zn2+ content. The present ceramics with a small amount of zinc substitution show a relatively small temperature coefficient of resonant frequency of 4.9–8.7 ppm/°C, ɛr of 57–58, and a Q×f value of 11 300–17 400 GHz. When x=0.01, the best combination of dielectric properties, a near‐zero temperature coefficient of resonant frequency of τf∼4.9 ppm/°C, ɛr∼57.6, and Q×f∼17 100 GHz, is obtained.
Properties of Triaxial Porcelain Bodies: Interpretation of Statistical Modeling
Authors: Correia S. L. , Oliveira A. P. N. , Hotza D. , Segadães A. M.
Published: October 2006

The effect of raw materials type and content on the properties of clay–feldspar–quartz compositions was studied using the statistical design of mixture experiments. Based on wall and floor tile industrial practice, 10 mixtures of three raw materials were selected and processed. Characterization results were used to calculate statistically significant and valid regression equations, relating fired body properties with clay, feldspar, and quartz contents in the unfired mixture. Such statistical modeling is discussed against quantitative X‐ray diffraction and scanning electron microscopy results. The glassy phase present was found to control the microstructure and the mechanical strength of the fired ceramic body.
Electrochemical Synthesis of Small SrTiO3 Particles
Authors: Tao Jiantao , Ma Junfeng , Wang Yonggang , Zhu Xiaoyi , Liu Jun , Jiang Xiaohui , Lin Botao , Ren Yang
Published: October 2006

Small strontium titanate (SrTiO3) particles with an average particle size of about 100 nm have been successfully synthesized by a simple and fast electrochemical route, in which Ti metal plates are used as electrodes and an aqueous solution of KOH and Sr(OH)2 as an electrolyte. Anodic sparks played a key role, and KOH concentration was one of the most significant factors that affected the appearance of anodic sparks in this method. XRD patterns indicated that the powders obtained in our study were a pure perovskite phase SrTiO3 with a cubic structure, whose size and morphology were subsequently studied by transmission electron microscopy. UV‐VIS result showed that the products had better UV absorption and visible light response than TiO2‐P25.
Fabrication of TiO2‐Organic Hybrid Dot Arrays Using Nanosecond Laser Interference Lithography
Authors: Segawa Hiroyo , Abrams Neal , Mallouk Thomas E. , Divliansky Ivan , Mayer Theresa S.
Published: October 2006

Laser interference lithography is an established fabrication technique for periodic arrays such as photonic crystals (PCs). In this paper, we report the fabrication of a TiO2‐organic hybrid periodic array by nanosecond laser interference lithography. TiO2‐organic hybrid films were prepared from titanium tetra‐n‐butoxide and 2‐(methacryloyloxy) ethyl acetoacetate (MEAcAc) by the sol–gel method. The films were irradiated by using 10 ns pulses of 355 nm diffracted light from a Nd:yttrium–aluminum–garnet laser. The complexes formed by the Ti alkoxide and the MEAcAc were decomposed by laser irradiation, and the irradiated parts remained as periodic dot arrays on the substrate after the development. The two‐dimensional array of this TiO2‐organic hybrid material was calcined at 450°C and formed an anatase TiO2 dot array. The refractive index measured was 2.00. These dots were crack free and adherent to the substrate.
Synthesis of Nd/Si Codoped YAG Powders via a Solvothermal Method
Authors: Wang Lidan , Zhang Ligong , Fan Yi , Luo Jingsong , Zhang Peiping , An Linan
Published: October 2006

We report the synthesis of single‐phased Nd/Si‐doped yttrium aluminum garnet powder via a solvothermal method by using ethanol as the solvent. The obtained powder exhibits a spherical shape, no agglomeration, and an average particle size of ∼300 nm, suitable for conventional powder processing. The effect of heat treatment on the lattice parameter and optical properties of the powder is also studied. The results are discussed in terms of Nd/Si solubility.
Alumina Nanopowder Production from Synthetic Bayer Liquor
Authors: Mazloumi Mahyar , Khalifehzadeh Razieh , Sadrnezhaad S. K. , Arami Hamed
Published: October 2006

Alkoxides are the most common precursors used for the production of alumina nanopowders. These materials are, however, expensive and corrosive. This paper introduces a new method for the production of alumina nanopowders by rapid cooling of a synthetic caustic sodium aluminate solution (Bayer liquor), followed by calcination in the presence of a surface‐stabilizing agent like 1,2‐dihydroxy‐3,5‐benzene disulfonic acid disodium salt (Tiron). The powders produced are characterized by differential thermal analysis, XRD, transmission electron microscopy, scanning electron microscope, and Brunauer–Emmet–Teller. A nanopowder of α‐alumina with an average crystallite size of 27.7 nm and an average particle size of 50 nm is produced.
Transformation Kinetics of Ba2Ti9O20 with ZrO2 Additive
Authors: Wu Ting‐Yi , Wei Wen‐Cheng J.
Published: October 2006

Pure Ba2Ti9O20 (BT29) was synthesized by a solid‐state reaction in one step with various amounts of ZrO2 powder additive. The transformation kinetics of BT29 were investigated by quantitative X‐ray diffractometry (XRD). The results show that stoichiometric powder mixtures transform to the BT29 phase by nucleation and growth mechanism between 1200° and 1300°C with 1.0 mol% ZrO2. The activation energy of the transformation was found to be 620±60 kJ/mol, but decreases to 515±30 kJ/mol when doped with 1.0 mol% ZrO2. The addition of ZrO2 possibly changes the phase transformation mechanism of BT29 from diffusion controlled to interface controlled.
Optical and Electrical Properties of Amorphous and Nanocrystalline (La0.8Sr0.2)0.9MnO3 Thin Films Prepared from Low‐Temperature Processing Technique
Authors: Suzuki Toshio , Awano Masanobu , Petrovsky Vladimir , Anderson Harlan U.
Published: October 2006

The results of a study on the optical and electrical properties of (La0.8Sr0.2)0.9MnO3 (LSM) thin films obtained by a polymeric precursor spin coating technique were presented. This method allowed preparation of optical quality thin films at annealing temperatures around 800°C. Amorphous and crystalline LSM thin films were studied by optical and electrical conductivity measurements. The energy‐dependent absorption coefficients for the crystalline specimen were calculated from optical spectra and extra absorption was observed in the range of 1.8–2.5 eV with the exchange‐gap excitation behavior in the 3–5 eV range. In comparison to the amorphous specimens, the electrical conductivity of the nanocrystalline specimen increased two to three orders of magnitude with decreasing activation energy. The charge carrier absorption model suggested an increase of the carrier concentration in the nanocrystalline specimen which may be a reason for the change in the electrical conductivity.
R‐Curve and Stress–Strain Behavior of Ferroelastic Ceramics
Authors: Jones Jacob L. , Hoffman Mark
Published: October 2006

The R‐curve and stress–strain behaviors in a variety of ferroelastic polycrystalline ceramic compositions are investigated and compared. These include soft and hard compositions of Pb(Zr,Ti)O3, Na0.5Bi4.5Ti4O15, PbNb2O6, PbTiO3, and Pb(Mg1/3Nb2/3)O3–Pb(Zr,Ti)O3. The fracture toughness enhancement is the highest in the soft PZT ceramic. The material parameters which influence the ferroelastic contribution to the toughness enhancement are extracted from the stress–strain behavior and compared with the measured toughness enhancement. Limited ferroelastic toughening is expected in the PbNb2O6 and Na0.5Bi4.5Ti4O15 compositions yet they exhibit a relatively large toughness enhancement. This toughness enhancement is attributed to frictional crack bridging through an exceptional intergranular fracture path. The frictional bridging effects are relieved by thermal annealing indicating some ferroelastic assistance in this mechanism.
Microstructures and Theoretical Bulk Modulus of Layered Ternary Tantalum Aluminum Carbides
Authors: Lin Zhijun , Zhuo Mujin , Zhou Yanchun , Li Meishuan , Wang Jingyang
Published: October 2006

Direct atomic resolution observations of the layered stacking characteristics of TaCx slabs and Al atomic planes in ternary Ta–Al–C carbides were achieved. Layered ternary Ta–Al–C compounds have diverse structures. A previously unknown Ta6AlC5 carbide, as well as intergrown Ta2AlC–Ta4AlC3 and Ta4AlC3–Ta6AlC5 structures were identified. Theoretical lattice parameters and bulk modulus of Ta2AlC, Ta3AlC2, Ta4AlC3, and Ta6AlC5 are presented. Furthermore, the Ta–C bonds are much stronger than the Ta–Al bonds in ternary Ta–Al–C carbides, which accounts for the enhancement of bulk modulus with increasing Ta–C layers.
Narrowband Microwave Dielectric Resonance and Negative Permittivity Behavior in Hydrogen‐Fired Al2O3–CuO Composites
Authors: Calame Jeffrey P. , Battat Jacob
Published: October 2006

The frequency‐dependent microwave complex permittivity of composites based on an Al2O3–CuO system is investigated at room temperature. The composites are formed by solution infusion of copper precursors into a porous Al2O3 matrix, followed by thermal decomposition to copper oxides and localized formation of copper aluminate compounds, and finally, H2 firing. The material exhibits a strong amplitude, with relatively narrowband dielectric resonance in the microwave frequency regime at intermediate levels of mass gain, which is reminiscent of a plasmon resonance. Large mass gains cause negative permittivity behavior below 6 GHz, consistent with a collisional Drude model of a semiconducting oxide phase.
Normal Sintering of (K,Na)NbO3‐Based Ceramics: Influence of Sintering Temperature on Densification, Microstructure, and Electrical Properties
Authors: Zhen Yuhua , Li Jing‐Feng
Published: October 2006

Normal sintering of Li‐doped and Li/Ta‐codoped potassium sodium niobate (KNbO3–NaNbO3, KNN)‐based ceramics was investigated to clarify the optimal sintering condition for densification, microstructure, and electrical properties. It was found that density increased greatly within a narrow temperature range but tended to decrease when the sintering temperature slightly exceeded the optimal one, accompanied by the appearance of abnormal grain growth, which was considered to be due to the intensified volatilization of alkali metal oxides. Piezoelectric and dielectric properties also showed a similar relationship between the density and sintering temperature, but the highest piezoelectric strain coefficients were obtained at the temperatures lower than that for the highest density, because both densification and composition affect the electrical properties. The highest d33 value of 206 pC/N was obtained for the Li‐ and Ta‐codoped KNN ceramics prepared at 1090°C.
Permittivity of Porous Titanate Dielectrics
Authors: Wing Zachary N. , Wang Brian , Halloran John W.
Published: October 2006

Relative permittivities ranging from 12 to 100 were obtained from porous titania. Relative permittivities from 8 to 30 were obtained from porous calcium magnesium titanates. Porosity was introduced as microporosity by partial sintering, as 15 μm diameter spherical pores with porogens, and by fabrication of a microcellular structure with cylindrical pores. The relative permittivity as a function of porosity was compared with effective media models. Permittivity could be fitted to the Bruggeman 1/3 power law over a porosity range from 5% to 78%.
Neutron Powder Diffraction Study of a Phase Transition in La0.68(Ti0.95Al0.05)O3
Authors: Ali Roushown , Izumi Fujio , Yashima Masatomo
Published: October 2006

Crystal structures and structural changes of the compound La0.68(Ti0.95Al0.05)O3 have been studied using neutron powder diffraction data and the Rietveld method in the temperature range from 25° to 592°C. The Rietveld profile‐fitting analyses of the neutron data and the synchrotron diffraction profile revealed that the crystal symmetry of the low‐temperature phase of La0.68(Ti0.95Al0.05)O3 is orthorhombic Cmmm (2ap× 2ap× 2ap; p: pseudo‐cubic perovskite). The unit‐cell and structural parameters were successfully refined with the orthorhombic Cmmm for the intensity data measured at 25°, 182°, and 286°C, and with the tetragonal P4/mmm (ap×ap× 2ap) for intensity data obtained at 388° and 592°C. The P4/mmm‐to‐Cmmm phase transition was found to be induced by tilting of the (TiAl)O6 octahedron. The tilt angle decreased with increasing temperature, reaching 0° at the Cmmm–P4/mmm transition temperature.
Atomistic Modeling Study of Surface Segregation in Nd:YAG
Authors: Aschauer Ulrich , Bowen Paul , Parker Stephen C.
Published: October 2006

This study investigates the composition of free surfaces of neodymium‐doped yttrium–aluminum–garnet, using energy minimization techniques. Atomistic modeling shows that the dopant is concentrated in a zone within 5 Å of the surface, the enrichment factor being around 1300 when comparing surfaces with bulk concentrations. It is shown that the (111) surface can incorporate 1.8 times as much Nd as the (110) surface, the latter commonly found in YAG morphologies. Our results indicate that by using nanocrystalline ceramics and by modifying crystal growth to form (111) surfaces, the Nd content and thus the laser power may be significantly increased.
Characterization of Calcium Titanate–Magnesium Titanate Eutectic by Scanning Microwave Microscopy
Authors: Zhang Qinxin , McGinn Paul J.
Published: October 2006

Microstructure and dielectric properties in a CaTiO3 (CT)–MgTiO3 (MT) diffusion couple were studied by scanning electron microscopy (SEM) and near‐field scanning microwave microscopy (SMM). Complex microstructures containing Mg2TiO4 (M2T) and MgTi2O5 (MT2) phases as well as eutectic structures of CT–MT and MT2–CT developed during cooling from the melt. Variations in the local dielectric properties observed in SMM images are correlated with the microstructures characterized by SEM/EDS. The SMM characterization clearly distinguished low‐dielectric‐constant MT and high‐dielectric‐constant CT phases. The M2T, MT, and MT2 phases have similar dielectric properties, and were more difficult to distinguish in the SMM. The phase development during melting and solidification, and SMM imaging limitations are discussed.
Experimental Evidence for the Development of Bimodal Grain Size Distributions by the Nucleation‐Limited Coarsening Mechanism
Authors: Sano Tomoko , Rohrer Gregory S.
Published: October 2006

It has recently been hypothesized that transient bimodal grain size distributions can arise from unimodal distributions during coarsening if the continued growth of a majority fraction of the crystals is arrested by the energy barrier to nucleate new layers. To test this hypothesis experimentally, SrTiO3 has been coarsened in a titania‐rich liquid at 1500°C. Measurements of the grain size distribution as a function of time show a transient bimodal distribution that consists of a constant number of larger grains growing many times faster than a decreasing number of much smaller grains. The observations are consistent with the nucleation‐limited coarsening theory, which provides a plausible explanation for the development of transient bimodal grain size distributions in systems of crystals bounded by singular surfaces.
Intrinsic Grain Boundary Mobility in Alumina
Authors: Dillon Shen J. , Harmer Martin P.
Published: October 2006

Ultra‐high purity alumina was sintered in hydrogen at temperatures ranging from 1325° to 2020°C. Normal grain growth was maintained in all samples and grain boundary mobilities were measured. The data represent the most complete measure of intrinsic grain boundary mobility for alumina grain growth currently available. There are two orders of magnitude of discrepancy between the calculated and measured intrinsic grain boundary mobility. It is proposed that this discrepancy results from the poor assumption of the Burke–Turnbull model, which suggests that grain boundaries are ideally disordered and atomically rough. Implications of these results on the mechanism of solid‐state single‐crystal conversion in alumina are also discussed.
Application of Hertzian Tests to Measure Stress–Strain Characteristics of Ceramics at Elevated Temperatures
Authors: Sánchez‐González Estíbaliz , Meléndez‐Martínez Juan J. , Pajares Antonia , Miranda Pedro , Guiberteau Fernando , Lawn Brian R.
Published: October 2006

A new method for evaluating the elastic–plastic properties of ceramics from room temperature up to the onset of creep based on Hertzian indentation testing is proposed. Indentation stress–strain curves are compiled for representative alumina and zirconia ceramics at prescribed temperatures. Deconvolution of the indentation stress–strain curves for each material provides a measure of Young's modulus, yield stress, and work‐hardening coefficient as a function of temperature, enabling construction of true stress–strain curves. The stress–strain curves flatten out with increasing temperature, in accordance with an expected increased plastic response at elevated temperatures.
Effects of APOE and CHRNA4 genotypes on retinal nerve fibre layer thickness at the optic disc and on risk for developing exfoliation syndrome
Authors: Ritland Jon Ståle , Utheim Tor Paaske , Utheim Øygunn Aass , Espeseth Thomas , Lydersen Stian , Semb Svein Ove , Rootwelt Helge , Elsås Tor
Published: October 2006

Purpose:  To investigate whether CHRNA4 and APOE genotypes influence retinal nerve fibre layer (RNFL) thickness at the optic disc, intraocular pressure (IOP) and the development of exfoliation syndrome (XFS).

Methods:  A sample of 88 healthy adults (aged 50–75 years) genotyped for polymorphisms of APOE and CHRNA4 underwent an eye examination including slit‐lamp examination and fundus photography, as well as measurements of visual acuity, refraction, IOP and RNFL thickness at the optic disc by optical coherence tomography. The Fisher−Boschloo unconditional full multinomial test and two sample t‐tests were used in the statistical analyses.

Results:  There was no correlation between CHRNA4 and APOE genotypes and average RNFL thickness at the optic disc in the two eyes. Mean IOP in the eyes of APOE2 carriers was 13.18 mmHg, whereas that in the eyes of non‐APOE2 carriers, at 14.82 mmHg, was significantly higher (p = 0.014). Exfoliation syndrome was found in one or both eyes in 15 persons. The presence of XFS was less likely in CC carriers of the CHRNA4 gene than in TT and TC carriers (p = 0.049).

Conclusions:  We found no significant difference in RNFL thickness at the optic disc in the different genotype carriers of the APOE and CHRNA4 genes, and thereby no evidence for increased loss of ganglion cells in the retina as an effect of these genes. APOE2 carriers had significantly lower IOP than non‐APOE2 carriers. However, both values are within the normal range and RNFL thickness measurements at the optic disc showed no difference between these two groups. In our study population, CC carriers of the CHRNA4 gene were less likely to develop XFS.
Acute bipolar mania: a systematic review and meta‐analysis of co‐therapy vs. monotherapy
Authors: Smith L. A. , Cornelius V. , Warnock A. , Tacchi M. J. , Taylor D.
Published: October 2006

Introduction:  The aim of this meta‐analysis was to systematically review the effectiveness of co‐therapy compared with monotherapy for people with bipolar mania.

Method:  MEDLINE, Embase, Psychinfo, The Cochrane Library and reference lists of retrieved studies were searched without language restrictions for randomized controlled trials evaluating co‐therapy compared with monotherapy for acute bipolar mania. Each trial was assessed for susceptibility to bias. Data on mania outcomes, withdrawals, extrapyramidal symptoms and weight were extracted and pooled effect estimates summarized as relative risks (RR) or differences in mean values (MD) where appropriate.

Results:  Eight eligible studies were included (1124 participants). Significant reductions in mania (Young Mania Rating Scale, YMRS) scores were shown for haloperidol, olanzapine, risperidone and quetiapine as co‐therapy compared with monotherapy with a mood stabilizer. For atypical antipsychotics combined, the pooled difference in mean scores was 4.41 (95% CI: 2.74, 6.07). Significantly more participants on co‐therapy met the response criterion (at least 50% reduction in YMRS score), RR 1.53 (1.31, 1.80). With some drugs, co‐therapy decreased tolerability compared with monotherapy, and resulted in greater weight gain. There were insufficient data to compare one co‐therapy regimen with another.

Conclusion:  The addition of antipsychotic treatment to established mood‐stabilizer treatment is more effective than mood‐stabilizer treatment alone.
Interleukin‐24, RANTES and CCR5 gene polymorphisms are not associated with chronic adult periodontitis
Authors: Savarrio L. , Donati M. , Carr C. , Kinane D. F. , Berglundh T.
Published: October 2006

Background and Objective:  Cytokines, such as interleukin‐10, and related genetic polymorphisms, have been implicated in the pathogenesis of chronic periodontitis. The aim of this study was to investigate a possible correlation between chronic periodontitis and genetic polymorphisms coding for two interleukin‐10 related chemokines [interleukin‐24 and regulated on activation, normal T cells expressed and secreted (RANTES)] as well as a RANTES receptor [CC chemokine receptor 5 (CCR5)].

Material and Methods:  A single‐blind, two‐centre, case‐controlled study was carried out with test patients from the Clinic of Periodontics, Göteborg University, and from the Department of Periodontology, Glasgow University, and control subjects from the undergraduate clinics of both schools. Blood samples were collected from 106 patients (56 women and 50 men, mean age 51.7 yr) with generalized, severe chronic periodontitis and from 69 periodontally healthy subjects (37 women and 32 men, mean age 53.3 yr). The polymerase chain reaction (PCR) was used to identify the genetic coding for interleukin‐24, RANTES and CCR5. Genotype and allele frequencies were compared between the test and control groups using Fischer's exact test at the 5% level of significance.

Results:  There were no statistically significant differences between patients with chronic periodontitis and control subjects, regarding genotype distribution or allele frequency, irrespective of smoking status, in the combined Glasgow and Gothenburg cohort or in the specific location cohorts. The allele frequencies for healthy and control subjects for RANTES gave a p‐value of 0.80 (allele G was 58.8% in healthy subjects and and 54.4% in subjects with periodontitis), for interleukin‐24 the p‐value was 0.90 (allele T was 56.2% in healthy subjects and and 54.9% in subjects with periodontitis) and for CCR5 the p‐value was 0.90 (the wild‐type allele was 85% in healthy subjects and and 82.7% in subjects with periodontitis).

Conclusion:  The interleukin‐24, RANTES and CCR5 polymorphisms investigated are not associated with chronic periodontitis.
Biophysical characterization of synthetic rhamnolipids
Authors: Howe Jörg , Bauer Jörg , Andrä Jörg , Schromm Andra B. , Ernst Martin , Rössle Manfred , Zähringer Ulrich , Rademann Jörg , Brandenburg Klaus
Published: October 2006

Synthetic rhamnolipids, derived from a natural diacylated glycolipid, RL‐2,214, produced by Burkholderia (Pseudomonas) plantarii, were analyzed biophysically. Changes in the chemical structures comprised variations in the length, the stereochemistry and numbers of the lipid chains, numbers of rhamnoses, and the occurrence of charged or neutral groups. As relevant biophysical parameters, the gel (β) to liquid crystalline (α) phase behavior of the acyl chains of the rhamnoses, their three‐dimensional supramolecular aggregate structure, and the ability of the compounds to intercalate into phospholipid liposomes in the absence and presence of lipopolysaccharide‐binding protein were monitored. Their biological activities were examined as the ability to induce cytokines in human mononuclear cells and to induce chemiluminescence in monocytes. Depending on the particular chemical structures, the physicochemical parameters as well as the biological test systems show large variations. This relates to the acyl chain fluidity, aggregate structure, and intercalation ability, as well as the bioactivity. Most importantly, the data extend our conformational concept of endotoxicity, based on the intercalation of naturally originating amphiphilic virulence factors into membranes from immune cells. This ‘endotoxin conformation’, produced by amphiphilic molecules with a hydrophilic charged backbone and apolar hydrophobic moiety, and adopting inverted cubic aggregate structures, causes high mechanical stress in target immune cells on integral proteins, eventually leading to cell activation. Furthermore, biologically inactive rhamnolipids with lamellar aggregate structures antagonize the endotoxin‐induced activity in a way similar to lipid A‐derived antagonists.
Functionally different pools of Shiga toxin receptor, globotriaosyl ceramide, in HeLa cells
Authors: Falguières Thomas , Römer Winfried , Amessou Mohamed , Afonso Carlos , Wolf Claude , Tabet Jean‐Claude , Lamaze Christophe , Johannes Ludger
Published: October 2006

Many studies have investigated the intracellular trafficking of Shiga toxin, but very little is known about the underlying dynamics of its cellular receptor, the glycosphingolipid globotriaosyl ceramide. In this study, we show that globotriaosyl ceramide is required not only for Shiga toxin binding to cells, but also for its intracellular trafficking. Shiga toxin induces globotriaosyl ceramide recruitment to detergent‐resistant membranes, and subsequent internalization of the lipid. The globotriaosyl ceramide pool at the plasma membrane is then replenished from internal stores. Whereas endocytosis is not affected in the recovery condition, retrograde transport of Shiga toxin to the Golgi apparatus and the endoplasmic reticulum is strongly inhibited. This effect is specific, as cholera toxin trafficking on GM1 and protein biosynthesis are not impaired. The differential behavior of both toxins is also paralleled by the selective loss of Shiga toxin association with detergent‐resistant membranes in the recovery condition, and comparison of the molecular species composition of plasma membrane globotriaosyl ceramide indicates subtle changes in favor of unsaturated fatty acids. In conclusion, this study demonstrates the dynamic behavior of globotriaosyl ceramide at the plasma membrane and suggests that globotriaosyl ceramide‐specific determinants, possibly its molecular species composition, are selectively required for efficient retrograde sorting on endosomes, but not for endocytosis.
Metabolic control of mitochondrial properties by adenine nucleotide translocator determines palmitoyl‐CoA effects
Authors: Ciapaite Jolita , Bakker Stephan J. L. , Diamant Michaela , Van Eikenhorst Gerco , Heine Robert J. , Westerhoff Hans V. , Krab Klaas
Published: October 2006

Inhibition of the mitochondrial adenine nucleotide translocator (ANT) by long‐chain acyl‐CoA esters has been proposed to contribute to cellular dysfunction in obesity and type 2 diabetes by increasing formation of reactive oxygen species and adenosine via effects on the coenzyme Q redox state, mitochondrial membrane potential (Δψ) and cytosolic ATP concentrations. We here show that 5 µm palmitoyl‐CoA increases the ratio of reduced to oxidized coenzyme Q (QH2/Q) by 42 ± 9%, Δψ by 13 ± 1 mV (9%), and the intramitochondrial ATP/ADP ratio by 352 ± 34%, and decreases the extramitochondrial ATP/ADP ratio by 63 ± 4% in actively phosphorylating mitochondria. The latter reduction is expected to translate into a 24% higher extramitochondrial AMP concentration. Furthermore, palmitoyl‐CoA induced concentration‐dependent H2O2 formation, which can only partly be explained by its effect on Δψ. Although all measured fluxes and intermediate concentrations were affected by palmitoyl‐CoA, modular kinetic analysis revealed that this resulted mainly from inhibition of the ANT. Through Metabolic Control Analysis, we then determined to what extent the ANT controls the investigated mitochondrial properties. Under steady‐state conditions, the ANT moderately controlled oxygen uptake (control coefficient C = 0.13) and phosphorylation (C = 0.14) flux. It controlled intramitochondrial (C = −0.70) and extramitochondrial ATP/ADP ratios (C = 0.23) more strongly, whereas the control exerted over the QH2/Q ratio (C = −0.04) and Δψ (C = −0.01) was small. Quantitative assessment of the effects of palmitoyl‐CoA showed that the mitochondrial properties that were most strongly controlled by the ANT were affected the most. Our observations suggest that long‐chain acyl‐CoA esters may contribute to cellular dysfunction in obesity and type 2 diabetes through effects on cellular energy metabolism and production of reactive oxygen species.
Investigation of Potential Glycogen Synthase Kinase 3 Inhibitors Using Pharmacophore Mapping and Virtual Screening
Authors: Dessalew Nigus , Bharatam Prasad V.
Published: October 2006

Glycogen synthase kinase‐3 is a serine/threonine kinase that has attracted significant drug discovery attention in recent years. To investigate the identification of new potential glycogen synthase kinase‐3 inhibitors, a pharmacophore mapping study was carried out using a set of 21 structurally diverse glycogen synthase kinase‐3 inhibitors. A hypothesis containing four features: two hydrophobic, one hydrogen bond donor and another hydrogen bond acceptor was found to be the best from the 10 common feature hypotheses produced by HipHop module of Catalyst. The best hypothesis has a high cost of 156.592 and higher best fit values were obtained for the 21 inhibitors using this best hypothesis than the other HipHop hypotheses. The best hypothesis was then used to screen electronically the NCI2000 database. The hits obtained were docked into glycogen synthase kinase‐3β active site. A total of five novel potential leads were proposed after: (i) visual examination of how well they dock into the glycogen synthase kinase‐3β‐binding site, (ii) comparative analysis of their FlexX, G‐Score, PMF‐Score, ChemScore and D‐Scores values, (iii) comparison of their best fit value with the known inhibitors and (iv) examination of the how the hits retain interactions with the important amino acid residues of glycogen synthase kinase‐3β‐binding site.
A Computational Approach to Botanical Drug Design by Modeling Quantitative Composition–activity Relationship
Authors: Wang Yi , Wang Xuewei , Cheng Yiyu
Published: October 2006

Herbal medicine has been successfully applied in clinical therapeutics throughout the world. Following the concept of quantitative composition–activity relationship, the presented study proposes a computational strategy to predict bioactivity of herbal medicine and design new botanical drug. As a case, the quantitative relationship between chemical composition and decreasing cholesterol effect of Qi‐Xue‐Bing‐Zhi‐Fang, a widely used herbal medicine in China, was investigated. Quantitative composition–activity relationship models generated by multiple linear regression, artificial neural networks, and support vector regression exhibited different capabilities of predictive accuracy. Moreover, the proportion of two active components of Qi‐Xue‐Bing‐Zhi‐Fang was optimized based on the quantitative composition–activity relationship model to obtain new formulation. Validation experiments showed that the optimized herbal medicine has greater activity. The results indicate that the presented method is an efficient approach to botanical drug design.
‘THE VISAGE OF OFFENCE’: A PSYCHOANALYTICAL VIEW OF FORGIVENESS AND REPENTANCE IN SHAKESPEARE'S PLAYS
Authors: Bishop Bernardine
Published: October 2006

ABSTRACT
This paper attempts to explore some aspects of the psychological effort and achievement that constitutes the nature of forgiveness. It looks at forgiveness through the lens of different emotional processes shown in Shakespeare's plays. It aims to trace some lines of development in Shakespeare's thought. It argues that both forgiveness and repentance are hard‐won and precarious psychic states, and that both call for considerable struggle and pain. It suggests that shallower and less evolved states of mind may sometimes masquerade as forgiveness and as repentance, and that there are certain spurious short cuts to both. Shakespeare reflects both authentic and inauthentic forgiveness and repentance at various moments in his plays.