bluuebunny/crossref_metadata_2025 huggingface dataset:
Physicochemical Degradation of Titania‐Stabilized Soluble Phosphate Glasses for Medical Applications
Authors: Navarro Melba , Ginebra Maria‐Pau , Clément Jerome , Salvador Martínez , Gloria Avila , Planell Josep A.
Published: July 2009

Four different formulations of phosphate glasses in the system P2O5–CaO–Na2O–TiO2 were developed. Their physicochemical, morphologic, and structural evolution was analyzed during in vitrodegradation in SBF (simulated body fluid) at 37°C up to 16 weeks. The results showed that the addition of TiO2 into the glass system enhanced both the elastic modulus and the chemical durability of the glasses. Indeed, the elastic modulus increased from 66.6 to 75.95 GPa and the weight loss percentage diminished from 1.6% to 0.3% with the addition of 8 mol% TiO2. A uniform and superficial degradation mechanism could be observed throughout the dissolution time by means of environmental scanning electron microscopy (ESEM), inductively coupled plasma mass spectroscopy (ICP‐MS), and Raman spectroscopy. The degradation process undergone by these glasses allows them to maintain their mechanical properties during the degradation process. Therefore, these materials offer an interesting choice for slowly resorbable materials in biomedical applications.
Measurement of Internal Stress in Glass Articles
Authors: Shepard Chester L. , Cannon Bret D. , Khaleel Mohammad A.
Published: July 2009

We have developed a method for measurement of internal stress in glass articles. The method uses Rayleigh‐scattered light from a properly polarized laser beam propagating through glass at an oblique angle. This light is imaged with an electronic focal plane array camera. The method is similar to earlier published methods except for the inclusion of an externally controlled phase retarder. The phase retarder allows for the success of the method. The method is suitable for use on flat or curved glass and is applicable over a broad range of residual stresses. Experimental results are provided showing the in‐plane stress throughout the thickness of a television glass sample.
Microthermal Analysis of Heat Conduction in Silicon Nitrides
Authors: Ye Jiping , Okada Akira
Published: July 2009

Local thermal response in silicon nitride materials was investigated with a microthermal analyzer. Two gas‐pressure‐sintered silicon nitride materials having basically different ultimate firing temperatures were examined. In sintered materials with coarse grains grown at higher temperatures, the bulk thermal conductivity was high while that of individual particles was rather lower due to the presence of impurities. The higher bulk thermal conductivity may be attributed to heat conduction through coarser grains. In sintered materials with finer grains, the bulk thermal conductivity was lower owing to the effects of grain boundaries, despite higher conductivity within individual grains.
Abrasive Wear Behavior of Heat‐Treated ABC‐Silicon Carbide
Authors: Zhang Xiao Feng , Lee Gun Y. , Chen Da , Ritchie R. O. , De Jonghe Lutgard C.
Published: July 2009

Hot‐pressed silicon carbide, containing aluminum, boron, and carbon additives (ABC‐SiC), was subjected to three‐body and two‐body wear testing using diamond abrasives over a range of sizes. In general, the wear resistance of ABC‐SiC, with suitable heat treatment, was superior to that of commercial SiC. When the fine‐scale (3 μm) diamond abrasives were used, it was found that thermal annealing at 1300°C increased the resistance to three‐body wear by a factor of almost three, and two‐body wear by a factor of almost two, compared with as‐hot‐pressed samples. Higher annealing temperatures, however, led to a decline in wear resistance from its highest value. Similar behavior was seen for 1300°C‐annealed samples subjected to 15 μm diamond abrasive, although higher‐temperature annealing at 1500°–1600°C enhanced the wear resistance again. When coarse abrasives (72 μm) were used, the wear resistance progressively increased with increased annealing temperature from ∼1000° to 1600°C. Corresponding transmission and scanning electron microscopy studies indicated that, whereas transgranular, conchoidal cracking was dominant in the mild abrasive wear with fine‐scale (3 μm) abrasives, intergranular cracking and subsequent grain pullout was far more predominant in the more severe abrasive wear with coarse abrasives. Because the hardness and indentation toughness were barely altered during thermal treatment, the observed wear behavior was attributed mainly to the thermally induced microstructural changes, including the crystallization of glassy grain‐boundary films, the possible strengthening of the boundaries due to the enhancement of the aluminum, and the formation of aluminum‐rich, coherent nanoscale precipitates in the matrix grains above 1300°C.
Grain Growth Control in Sb2O3‐Doped Zinc Oxide
Authors: Daneu Nina , Rečnik Aleksander , Bernik Slavko
Published: July 2009

Microstructure development in Sb2O3‐doped ZnO was studied to evaluate the influence of inversion boundaries (IBs) on ZnO grain growth. In general, the addition of Sb2O3 is believed to inhibit the ZnO grain growth via the formation of spinels and IBs, but we have shown that even the conditions of exaggerated grain growth can be created in this system. We designed an experiment for diffusional doping of ZnO under slightly increased partial pressure of Sb2O3. In the high‐concentration regime we observed no spinels, and yet the ZnO grains were small and inhibited in growth, while in the low‐concentration regime we found huge grains, several times larger than normal ZnO grains, showing an obvious exaggerated growth. By controlling the number of nuclei with IBs we can design coarse‐grained microstructures even with Sb2O3 doping, which has far‐reaching implications in the production of low‐voltage varistor devices.
Molecular Dynamics Simulations of Amorphous Si–C–N Ceramics: Composition Dependence of the Atomic Structure
Authors: Resta Nicoletta , Kohler Christopher , Trebin Hans‐Rainer
Published: July 2009

We have performed classical molecular dynamics simulations of amorphous Si–C–N materials. The dependence of the local order and of the microstructure on the chemical composition was investigated. Our simulations show that for a stoichiometric nitrogen/silicon ratio equal to or higher than 4/3, the amorphous ceramic separates into different amorphous domains, namely C‐rich, SiN‐rich, and SiC‐rich phases. Below this ratio, the material is composed of mixed structures, homogeneously spread within the material. For a very particular composition range, we found that carbon atoms crystallize into monoatomic graphitic layers surrounding the SiN‐rich domains.
Metastable Phase Formation in Plasma‐Sprayed ZrO2 (Y2O3)–Al2O3
Authors: Zhou Xinzhang , Shukla Vijay , Cannon W. Roger , Kear Bernard H.
Published: July 2009

Rapidly solidified ZrO2 (Y2O3)–Al2O3 powders were prepared by melting fine‐particle aggregates in a high‐enthalpy plasma flame and then rapidly quenching them in cold water or on a copper chill plate. To ensure complete melting and homogenization of all the particles before quenching, the water‐quenching treatment was often repeated two or even three times. The resulting melt‐quenched powders and splats displayed a variety of metastable structures, depending on composition and cooling rate. ZrO2‐rich material developed an extended solid solution phase, whereas eutectic material formed a nanofibrous or amorphous structure. Under high cooling rate conditions, the ZrO2‐rich material developed a nanocomposite structure (t‐ZrO2+α‐Al2O) directly by melt‐quenching, whereas, more typically, such a structure was developed only after postannealing of the as‐quenched metastable material.
High‐Temperature Strength of Sinter‐Forged Silicon Nitride with Lutetia Additive
Authors: Kondo Naoki , Asayama Masahiro , Suzuki Yoshikazu , Ohji Tatsuki
Published: July 2009

A sinter‐forging technique was successfully applied to fabricate a silicon nitride with a lutetia (Lu2O3) additive. The sinter‐forged specimen had a strongly anisotropic microstructure where rodlike silicon nitride grains preferentially aligned perpendicular to the forging direction. The specimen exhibited superior strength of ∼700 MPa at 1500°C. This strength was highest when compared with previous silicon nitrides at temperatures >1400°C. Such superior high‐temperature strength was attributed to grain alignment as well as to the refractory grain‐boundary glassy phase and the existence of glass‐free grain boundaries.
Determining the Toughness of Ceramics from Vickers Indentations Using the Crack‐Opening Displacements: An Experimental Study
Authors: Kruzic Jamie J. , Ritchie Robert O.
Published: July 2009

Recently, a method for evaluating the fracture toughness of ceramics has been proposed by Fett based on the computed crack‐opening displacements of cracks emanating from Vickers hardness indentations. To verify this method, experiments have been conducted to determine the toughness of a commercial silicon carbide ceramic, Hexoloy SA, by measuring the crack‐opening profiles of such Vickers indentation cracks. Although the obtained toughness value of Ko= 2.3 MPa·m1/2 is within 10% of that measured using conventional fracture toughness testing, the computed crack‐opening profiles corresponding to this toughness display poor agreement with those measured experimentally, raising concerns about the suitability of this method for determining the toughness of ceramics. The effects of subsurface cracking and cracking during loading are considered as possible causes of such discrepancies, with the former based on direct observations of lateral subsurface cracks below the indents.
Preparation of Polymethylmethacrylate‐Reinforced Functionally Graded Hydroxyapatite Composites
Authors: Ohgaki Masataka , Yamashita Kimihiro
Published: July 2009

A functionally graded hybridization approach has been used in the formation of polymer‐ceramic composites of polymethylmethacrylate (PMMA) and hydroxyapatite (HAp). HAp was successfully reinforced by sedimentary HAp distributions on a PMMA matrix using a centrifuge to avoid stress convergence on the interface. The stress‐strain curves of the functionally graded PMMA‐HAp composite showed sufficient mechanical strength with reduced brittleness. Scanning electron micrographs also showed evidence of exposed HAp on the surface of the composites.
Amorphous Silicon Carbonitride Fibers Drawn from Alkoxide Modified Ceraset™
Authors: Saha Atanu , Shah Sandeep R. , Raj Rishi
Published: July 2009

We show that the rheology of a silazane‐based precursor for a silicon carbonitride ceramic can be radically altered by reacting it with an alkoxide precursor. This modified precursor can be drawn into fibers by a simple process. The fiber‐friendly rheology of the modified precursor is ascribed to the creation of linear polymer chains by a reaction between silazanes and alkoxides. The ceramic fibers made by this process have excellent mechanical properties, reaching tensile strengths of 2.8 GPa. Their structure is amorphous.
Thermodynamic Behavior of Copper‐Coated Silicon Carbide Particles during Conventional Heating and Spark Plasma Sintering
Authors: Zhang Rui , Gao Lian , Guo Jingkun
Published: July 2009

75Cu·25SiC (vol%) compacts were prepared using copper‐coated SiC particles and spark plasma sintering (SPS). The preliminary thermal performance of the coated particles was determined using simultaneous DSC‐TG‐MS measurement. Characterization of compacts using XRD and SEM techniques was conducted to investigate the physical and chemical changes during the SPS operation. It was found that CuO decomposed at 850° and 500°C during conventional heating and SPS, respectively. Cu2O facilitated the densification of Cu/SiC composites. The optimized sintering temperature of Cu/SiC composites using SPS was ∼730°C. The compacts showed improved hardness because of the SiC reinforcement.
Influence of the Manufacturing Process on Corrosion Behavior of Soda‐Lime‐Silicate Glassware
Authors: Sharma Anju , Jain Himanshu , Carnali Joseph O. , Lugo Guillermo Manuel
Published: July 2009

The reaction of soda‐lime‐silicate glassware with model cleaning solutions gives rise to a systematic pattern of inhomogeneous corrosion. This corrosion is not uniform on the entire surface, but is localized only to certain regions of the glassware. The surface composition, as determined by X‐ray photoelectron spectroscopy, and the microstructure, as characterized by optical and scanning electron microscopy, vary considerably in different regions of the glassware. The visibly heterogeneous corrosion pattern, which correlates with the compositional and structural inhomogeneities, is explained in terms of surface conditions that exist during different stages of glass manufacturing. The role of sodium disilicate in solution is also explored for promoting inhomogeneous glass corrosion.
Method for Production of α‐Alumina Whiskers via Vapor‐Liquid‐Solid Deposition
Authors: Valcárcel Víctor , Cerecedo Carmen , Guitián Francisco
Published: July 2009

α‐alumina (α‐Al2O3, corundum) fibers exhibit high thermal and chemical stability, as well as good mechanical properties, even at high temperatures. Such characteristics make them good candidates for use in composites. Nevertheless, very few methods of producing α‐Al2O3 fibers are available. In the present work, we describe a method that uses aluminum pieces deposited on SiO2 powder, in an argon atmosphere, at temperatures in the range 1300°–1600°C. The α‐Al2O3 fibers are obtained via vapor‐liquid‐solid deposition. The novel addition of nickel and cobalt (or their oxides) allows the use of temperatures >1500°C, resulting in improved fiber production. We demonstrate that the metals do not contaminate the fibers produced in this way. Finally, we also estimate the tensile strength of the Al2O3 fibers produced through this method.
Microwave Dielectric Properties of RE1−xRE′xTiNbO6 [RE = Pr, Nd, Sm; RE′= Gd, Dy, Y] Ceramics
Authors: Surendran Kuzhichalil Peethambaran , Varma Manoj Raama , Mohanan Pezholil , Sebastian Mailadil Thomas
Published: July 2009

The microwave dielectric properties of rare‐earth titanium niobates can be tailored by preparing solid‐solution phases between RETiNbO6 [RE = Pr, Nd, Sm] and RE′TiNbO6 [RE′= Gd, Dy, Y] microwave dielectric ceramics. Dielectric ceramics based on solid‐solution phases RE1−xRE′xTiNbO6 are prepared by the conventional solid‐state ceramic route for different values of x. The ceramic samples are characterized by XRD, SEM, and microwave methods. Ceramics based on RETiNbO6 belonging to aeschynite group show a positive value of τf, and those based on RE′TiNbO6 belonging to the euxenite group have a negative value of τf. The solid‐solution phases between aeschynites and euxenites show intermediate dielectric constant and τf values. The results indicate the possibility of tailoring the microwave dielectric properties by varying the composition of solid‐solution phases. The range of solid solubility of euxenites in aeschynites and aeschynites in euxenites are different for different rare‐earth ions. The ceramics have low sinterability and a high dielectric loss factor near the vicinity of aeschynite to euxenite transition. The value of dielectric constant changes abruptly close to the transition point. The abrupt variation in microwave dielectric properties indicate a first‐order phase transition at x= 0.86 in Pr1−x Gd xTiNbO6, x= 0.48 in Nd1−x Dy xTiNbO6 and x= 0.27 in Sm1−xY x TiNbO6 ceramics. The dielectric constant and the sign of τf of the solid‐solution phases are found to depend on the average ionic radius of the rare‐earth ions in RE1−xRE′xTiNbO6. The euxenite to aeschynite phase transition occurs at an average ionic radius of 0.945 Å in all three systems of solid‐solution phases.
Characterization by Multinuclear High‐Resolution NMR of Hydration Products in Activated Blast‐Furnace Slag Pastes
Authors: Bonk Fábio , Schneider José , Cincotto Maria Alba , Panepucci Horácio
Published: July 2009

The effect of activators on the hydration of granulated blast‐furnace slag (gbfs) was studied through compressive strength measurements, 29Si, 27Al, and 23Na high‐resolution nuclear magnetic resonance, and X‐ray diffraction. Four different activations containing sodium hydroxide, sodium silicate, and/or calcium hydroxide (CH) were considered, at fixed amounts of alkali: 5% Na2O, 5% Na2O‐2.5% CH, 5% Na2O‐7.5% SiO2, and 5% Na2O‐2.5% CH‐7.5% SiO2. Silicate‐activated gbfs cements have greater compressive strength than Portland cements over the whole period of study (1 yr). Also, silicate‐free activated gbfs cements have poorer mechanical strength than silicate‐activated cements. In fact, substantial structural differences were observed between hydration products in both kinds of activations. In silicate‐activated pastes there exists an intimate mixture of C‐S‐H layers and AFm‐like arrangements containing Al in octahedral sites bonded to the silicate layers, originated either from phase intergrowths or from a high density of Ca‐Al incorporation in the interlayer spaces of C‐S‐H. In pastes obtained from silicate‐free activation of gbfs there is a better chemical and structural definition among C‐S‐H and calcium aluminate hydrate domains (AFm and hydrogarnet).
Processing and Properties of a Porous Oxide Matrix Composite Reinforced with Continuous Oxide Fibers
Authors: Holmquist Magnus G. , Lange Fred F.
Published: July 2009

A process to manufacture porous oxide matrix/polycrystalline oxide fiber composites was developed and evaluated. The method uses infiltration of fiber cloths with an aqueous slurry of mullite/alumina powders to make prepregs. By careful manipulation of the interparticle pair potential in the slurry, a consolidated slurry with a high particle density is produced with a sufficiently low viscosity to allow efficient infiltration of the fiber tows. Vibration‐assisted infiltration of stacked, cloth prepregs in combination with a simple vacuum bag technique produced composites with homogeneous microstructures. The method has the additional advantage of allowing complex shapes to be made. Subsequent infiltration of the powder mixture with an alumina precursor was made to strengthen the matrix. The porous matrix, without fibers, possessed good thermal stability and showed linear shrinkage of 0.9% on heat treatment at 1200°C. Mechanical properties were evaluated in flexural testing in a manner that precluded interlaminar shear failure before failure via the tensile stresses. It was shown that the composite produced by this method was comparable to porous oxide matrix composites manufactured by other processes using the same fibers (N610 and N720). The ratio of notch strength to unnotch strength for a crack to width ratio of 0.5 was 0.7–0.9, indicating moderate notch sensitivity. Interlaminar shear strength, which is dominated by matrix strength, changed from 7 to 12 MPa for matrix porosity ranging from 38% to 43%, respectively. The porous microstructure did not change after aging at 1200°C for 100 h. Heat treatment at 1300°C for 100 h reduced the strength for the N610 and N720 composites by 35% and 20%, respectively, and increased their brittle nature.
Dynamic Evolution of Grain‐Boundary Films in Liquid‐Phase‐Sintered Ultrafine Silicon Carbide Material
Authors: Gu Hui , Nagano Takayuki , Zhan Guo‐Dong , Mitomo Mamoru , Wakai Fumihiro
Published: July 2009

Spatially resolved electron energy‐loss spectroscopy (EELS) analysis revealed a dynamic evolution of grain‐boundary (GB) films in a liquid phase (Al2O3–Y2O3–CaO) sintered β‐SiC, which had been deformed both in tension and in compression. An effective chemical width was measured from the oxygen segregation to GBs. Significant increase of Al content in GB films was correlated to devitrification of amorphous pockets to form YAG during both deformations. This brought Y into and expelled Al from the pockets. The extra Al was pushed into GBs to form alumina‐based films. Al‐Y interdiffusion between GB films and pockets is related to deformation time, indicating a constant and limited interdiffusion rate. This evolution of GB films demonstrated that the dynamic process equilibrated these intergranular regions and phases. GB sliding and interdiffusion among intergranular regions were common mechanisms for both deformation modes. Fracture was mainly caused by YAG formation.
Rim Structure in Ti(C0.7N0.3)–WC–Ni Cermets
Authors: Kim Sungwon , Min Kyoung‐hoon , Kang Shinhoo
Published: July 2009

The evolution of rim structures during the liquid‐phase sintering of Ti(C0.7N0.3)·xWC·20Ni (x= 5–25 wt%) was investigated under a variety of sintering conditions and densification procedures. In addition, the onset of formation of the surrounding structures in the system was examined by analyzing the microstructures and rim compositions. The compositions of the inner and outer rims were found to vary with sintering temperature and holding time. The results indicate that the inner rim forms at sintering temperature and the outer rim forms thereafter during the sintering or cooling stage of sintering. The coalescence of Ti(C,N) appears to occur at the sintering temperature to a great extent before the formation of the rim phases.
Evolution of Texture in Rhabdophane‐Derived Monazite Coatings
Authors: Mogilevsky Pavel , Hay Randall S. , Boakye Emmanuel E. , Keller Kristen A.
Published: July 2009

Microstructure and texture development of fiber coatings of rhabdophane‐sol‐derived monazite was studied. As‐deposited textures and orientation relationships during phase transformations were determined by TEM. Monazite coatings had a crystallographic texture relict from that of as‐deposited rhabdophane, with layers of rod‐shaped particles that changed orientation by 90° across layers. Heat treatment at 1200°C of minicomposites with these coated fibers caused considerable monazite grain coarsening, and disappearance of the texture.
Fracture‐Mode Change in Alumina‐Silicon Carbide Composites Doped with Rare‐Earth Impurities
Authors: Deng Zhen‐Yan , Zhou You , Brito Manuel E. , Yang Jian‐Feng , Ohji Tatsuki
Published: July 2009

Al2O3‐5 vol% SiC particle composites doped with 800 ppm rare‐earth impurities (Y3+, Nd3+, and La3+) were fabricated by hot‐pressing at a temperature of 1550°C. Doping of rare‐earth impurities in Al2O3‐SiC composites led to a fracture‐ mode change from transgranular in dopant‐free composites to intergranular in rare‐earth‐doped composites. The fracture mode change obviously increased the crack deflection so that the fracture toughness of rare‐earth‐doped composites was higher than that of the composites without dopants, especially for the Nd3+‐ and La3+‐doped composites. It was found that the fracture‐mode change originated from a weak grain‐boundary bonding caused by co‐segregation of the rare‐earth dopants and Si4+ ions dissolved from the SiC particle surfaces.
Fabrication of Dense Nanostructured Silicon Carbide Ceramics through Two‐Step Sintering
Authors: Lee Young‐Il , Kim Young‐Wook , Mitomo Mamoru , Kim Doh‐Yeon
Published: July 2009

SiC powder compacts were prepared with Al2O3, Y2O3, and CaO powders. By two‐step sintering, fully dense nanostructured SiC ceramics with a grain sizes of ∼40 nm were obtained. The grain size–density trajectories are compared with those of conventional sintering processes.
(Bi1/2Na1/2)TiO3–Ba(Cu1/2W1/2)O3Lead‐Free Piezoelectric Ceramics
Authors: Wang Xiaoxing , Chan Helen Lai‐Wa , Choy Chung‐Loong
Published: July 2009

(Bi1/2Na1/2)TiO3with 0–6 mol% Ba(Cu1/2W1/2)O3(BNT‐BCW), a new member of the BNT‐based group, has been prepared following the conventional mixed oxide route. The compacted bodies were sintered at 1130°C for 2 h to get dense ceramics. The addition of BCW into BNT ceramics facilitated the poling process because of a reduction in leakage current. 0.995BNT·0.005BCW ceramics exhibit a relatively high piezoelectric constant (d33= 80 × 10−12C/N) and a relatively low dielectric loss (tan δ= 1.5%). Increased amount of BCW was found to increase the dielectric constant and loss of BNT‐BCW ceramics and to suppress the grain growth. During sintering, some BCW diffuses into the lattice of BNT to form a solid solution and some remains on the grain boundaries.
Effect of Grain Boundaries on Thermal Conductivity of Silicon Carbide Ceramic at 5 to 1300 K
Authors: Watari Koji , Nakano Hiromi , Sato Kimiyasu , Urabe Kazuyoshi , Ishizaki Kozo , Cao Shixun , Mori Katsunori
Published: July 2009

The thermal conductivity of a SiC ceramic was measured as 270 W·m−1·K−1 at room temperature. At low temperatures (T < 25 K), the decrease in the conductivity was proportional to T3 on a logarithmic scale, which indicated that the conductivity was controlled by boundaries. The calculated phonon mean free path in the ceramic increased with decreased temperature, but was limited to ∼4 μm, a length almost equal to the grain size, at temperatures below 30 K. We concluded that the thermal conductivity of the ceramic below 30 K was influenced significantly by grain boundaries and grain junctions.
Indentation‐Induced Amorphization in Mullite Single Crystals
Authors: Schmücker Martin , Schneider Hartmut , Kriven Waltraud M.
Published: July 2009

Hardness indentations with a Vickers pyramid under a load as low as 0.1 N applied at room temperature induce amorphization in single‐crystal mullite when applied to the (001) crystallographic face. Different zones of damage were identified via TEM. Directly under the indenter, in the region of high‐compressive stress, mullite becomes amorphous. Further out toward the matrix material, there exists a region of high plastic deformation in the form of dislocation networks, radial microcracks, and bend contours. The Vickers‐induced damage is comparable to that produced by dynamic shock or intense ball milling of mullite.
Renal function and cardiovascular risk profile after conversion from ciclosporin to tacrolimus: prospective study in 80 liver transplant recipients
Authors: BECKEBAUM S. , KLEIN C. , VARGHESE J. , SOTIROPOULOS G. C. , SANER F. , SCHMITZ K. , GERKEN G. , PAUL A. , CICINNATI V. R.
Published: July 2009

Aliment Pharmacol Ther 30, 834–842

Background Increased risk of cardiovascular and cerebrovascular disease in liver transplant recipients results in particular from the side effects of calcineurin inhibitor‐based immunosuppressive therapy. Several studies have demonstrated a more favourable outcome for patients receiving tacrolimus (TAC) as compared with ciclosporin (CS).

Aim To investigate the effects of conversion from CS to TAC on cardiovascular risk factors and renal function in liver transplant recipients.

Methods In a prospective study, all except two patients had chronic kidney disease stages 2–4 (n = 80), according to estimated glomerular filtration rate using the abbreviated Modification of Diet in Renal Disease equation.

Results Conversion was accompanied with a mean decrease of total cholesterol from 194.6 ± 54.0 mg/dL to 175.8 ± 44.2 mg/dL (P < 0.001), low density lipoprotein cholesterol from 106.7 ± 39.2 mg/dL to 90.9 ± 28.6 mg/dL (P < 0.001) and mean arterial blood pressure values from 102.2 ± 13.2 mm Hg to 95.9 ± 11.7 mm Hg (P < 0.001). Renal function remained stable. No cases ofde novodiabetes mellitus were identified. The Framingham risk score was significantly reduced from 5.2 ± 4.4 at baseline to 4.4 ± 5.3 after 12 months (P = 0.006).

Conclusions Conversion from CS to TAC has been shown to improve the cardiovascular risk profile and may retard further decline of renal function after liver transplantation.
Recent incidence trends and sociodemographic features of oesophageal and gastric cancer types in an English region
Authors: GAJPERIA C. , BARBIERE J. M. , GREENBERG D. , WRIGHT K. , LYRATZOPOULOS G.
Published: July 2009

Aliment Pharmacol Ther 30, 873–880

Background  Oesophageal and gastric cancers comprise various common tumour types with possible different aetiology and historically different incidence trends.

Aim  To enhance and update evidence about the descriptive epidemiology of oesophageal and gastric cancers.

Methods  Population‐based information from the East of England was available on 16 319 (65% male) incident cases of oesophago‐gastric cancer (ICD‐10 C150–169) diagnosed during 1995–2006. Age‐standardized incidence trends by gender and deprivation groups and sex ratios were compared for four different tumour types [oesophageal squamous cell carcinoma (OSCC), oesophageal adenocarcinoma (OAC), junctional/cardia adenocarcinoma (JCA), and non‐cardia gastric adenocarcinoma (NCGA)].

Results  Between 1995–1997 and 2004–2006, the age‐standardized incidence of OAC and JCA increased slightly (by 4% and 6% in men and 17% and 8% in women respectively), with a sex ratio >4 for both. Conversely, OSCC and NCGA incidence decreased (−20% and −32% in men and −15% and −26% in women respectively), with sex ratio of <2 for both. In men, OSCC and NCGA incidence was associated with increasing deprivation.

Conclusions  Within the study context, there was a modest rise in OAC and JCA incidence. OAC and JCA share common incidence trends and sociodemographic features (contrasting with those of OSCC and NCGA cancers).
Hybrid mathematical model of glioma progression
Authors: Tanaka M. L. , Debinski W. , Puri I. K.
Published: July 2009

Objectives:  Gliomas are an important form of brain cancer, with high mortality rate. Mathematical models are often used to understand and predict their behaviour. However, using current modeling techniques one must choose between simulating individual cell behaviour and modeling tumours of clinically significant size.

Materials and Methods:  We propose a hybrid compartment‐continuum‐discrete model to simulate glioma growth and malignant cell invasion. The discrete portion of the model is capable of capturing intercellular interactions, including cell migration, intercellular communication, spatial cell population heterogeneity, phenotype differentiation, epigenetic events, proliferation, and apoptosis. Combining this with a compartment and continuum model allows clinically significant tumour sizes to be evaluated.

Results and Conclusions:  This model is used to perform multiple simulations to determine sensitivity to changes in important model parameters, specifically, the fundamental length parameter, necrotic cell degradation rate, rate of cell migration, and rate of phenotype transformation. Using these values, the model is able to simulate tumour growth and invasion behaviour, observed clinically. This mathematical model provides a means to simulate various tumour development scenarios, which may lead to a better understanding of how altering fundamental parameters can influence neoplastic progression.
Context‐dependent running speed in funnel‐web spiders from divergent populations
Authors: Pruitt Jonathan N. , Husak Jerry F.
Published: July 2009

1. Locomotor performance can influence individual fitness through several ecological contexts, such as prey capture and predator escape. One means of determining which contexts act as significant selective forces on running speed is to quantify individual speed in each context. The underlying hypothesis is that animals will exhibit their highest speeds in contexts most crucial to fitness.

2. We measured running speeds in three ecological contexts (prey capture, fleeing predators and territory defence) in lab‐reared offspring of the funnel‐web spider Agelenopsis aperta collected from two arid grassland and two riparian populations. Arid populations experience little predation pressure, are prey limited, and are highly territorial; riparian populations experience high predation, have high prey availability, and are less territorial in nature.

3. The offspring of arid individuals exhibited their highest burst speeds in territory defence, and ran more slowly in response to predator threats. The offspring of riparian populations, however, ran fastest when responding to predatory threats and displayed lower velocities in prey capture and territory defence. Thus, our findings support the hypothesis that A. aperta are selected to exhibit their highest speeds in contexts most important to their fitness.

4. Contextual use of running speed can differ among conspecific populations experiencing differing selective forces on locomotion.
Hornton Stone: battlefields, buildings and Jurassic seas
Authors: Radley Jonathan D.
Published: July 2009

The Hornton Stone is an unusually pure ooidal ironstone of the Lower Jurassic Marlstone Rock Formation, cropping out on the Edge Hill escarpment and adjacent ironstone plateau in central England. The stone has been quarried for building and ornamental purposes since Medieval times, and more recently as a source of iron ore. Local quarries and buildings provide excellent opportunities to appreciate its fossil content, sedimentary structures and origin.
Geological mysteries of the Plain of Jars begin to unravel
Authors: Baldock Jeremy , Van Den Bergh Julie
Published: July 2009

The Plain of Jars in north‐eastern Laos is home to over 2000 stone jars varying in size from 100 kg to over 30 tonnes. The jars were probably made between 1500 and 2500 years ago; however, who by is not known, as the indigenous people have only lived in the area for 1000 years. Local legend speaks of these jars being used to store Lao‐Lao or rice whisky; research indicates that these jars were part of loca funerary rites. There are currently 60 known jar sites, where anywhere between one and 350 individual jars are recorded. The jars are constructed from a variety of lithologies although a few basic rules to selecting suitable rocks have been observed. This study outlines which rock types have been used and how the characteristics of the rock mass controlled the jar makers' selection.
Trappin‐2/Elafin: a novel innate anti‐human immunodeficiency virus‐1 molecule of the human female reproductive tract
Authors: Ghosh Mimi , Shen Zheng , Fahey John V. , Cu‐Uvin Susan , Mayer Kenneth , Wira Charles R.
Published: July 2009

Trappin‐2/Elafin is a serine protease inhibitor that plays a major role as an anti‐inflammatory mediator at mucosal surfaces. In addition, Trappin‐2/Elafin has antibacterial activity against Gram‐positive and Gram‐negative bacterial and fungal pathogens. In this study we examined the production of Trappin‐2/Elafin by epithelial cells from the human upper and lower female reproductive tract as well as its activity as an anti‐human immunodeficiency virus (HIV)‐1 molecule. We found that primary uterine, Fallopian tube, cervical and ectocervical epithelial cells produce Trappin‐2/Elafin constitutively and that production of Trappin‐2/Elafin is enhanced following stimulation with Poly(I:C), especially by the uterine cells. Given the presence of Trappin‐2/Elafin in the reproductive tract, we tested the ability of recombinant Trappin‐2/Elafin to inhibit HIV‐1, an important sexually transmitted pathogen. We found that recombinant Trappin‐2/Elafin was able to inhibit both T‐cell‐tropic X4/IIIB and macrophage‐tropic R5/BaL HIV‐1 in a dose‐dependent manner. The inhibitory activity was observed when virus was incubated with Trappin‐2/Elafin but not when Trappin‐2/Elafin was added to cells either before infection or after infection. This suggests that the mechanism of inhibition is likely to be a direct interaction between HIV‐1 and Trappin‐2/Elafin. Additionally, we measured the levels of secreted Trappin‐2/Elafin in cervico‐vaginal lavages (CVL) from both HIV‐positive and HIV‐negative women and found that average levels of secreted Trappin‐2/Elafin were higher in the CVL from HIV‐negative women, although the values did not reach statistical significance. We also found that women at the secretory phase of the menstrual cycle produced more Trappin‐2/Elafin in CVL relative to women at the proliferative phase of the menstrual cycle. Our data suggest that Trappin‐2/Elafin might be an important endogenous microbicide of the female reproductive tract that is protective against HIV‐1.
Effect of sugar on the extrusion of maize grits and wheat flour
Authors: Carvalho Carlos W. P. , Mitchell John R.
Published: July 2009

Summary The influence of added sucrose on the degree of expansion and extent of starch conversion on extrusion processing of wheat flour and maize grits has been reported. Very different behaviour was found for the two cereal systems. In agreement with previous work, replacement of maize by sucrose at constant water content reduced the specific mechanical energy and as a consequence, reduced the degree of starch conversion and sectional expansion. In contrast, replacing wheat flour by sucrose even at levels as high as 20% of the flour weight had little effect. Possible causes discussed were less efficient plasticization of wheat flour by sucrose compared with maize grits at low water contents, a specific role for gluten and the larger particle size of maize grits compared with wheat flour.
Testing causal structure in the biogeography of avian extinctions on oceanic islands
Authors: Karels Tim J. , Dobson F. Stephen , Zimbler‐DeLorenzo Heather S. , Skibiel Amy L.
Published: July 2009

In their recent comment in this journal, T. M. Blackburn and colleagues called into question the use of standardized partial regression modelling (also called path analysis and structural equation modelling) when null expectations for regression coefficients are not zero. Here, we answer their critique by showing how randomization can be used to illuminate and interpret causal modelling in analyses that have non‐zero expectations. Causal modelling is a powerful tool that can yield novel insights in biogeography when properly interpreted.
Asthma, smoking and BMI in adults with intellectual disabilities: a community‐based survey
Authors: Gale L. , Naqvi H. , Russ L.
Published: July 2009

Background  Recent research evidence from the general population has shown that tobacco smoking and raised body mass index (BMI) are associated with worse asthma outcomes. There are indications that asthma morbidity and mortality may be higher among people with intellectual disabilities (ID) than the general population, but the reason for this is not known. This is the first study to investigate the extent of smoking and higher than recommended BMI among adults with ID and a diagnosis of asthma.

Method  Health‐related data for 1097 adults with ID were collected from 28 primary care practices in Bristol, UK.

Results  Prevalence of asthma in this sample of adults with ID was 12% which was much higher than among the general population living in the region. The 132 patients with asthma were found to be nearly twice as likely to be current smokers as patients with ID who did not have asthma (29.5% vs. 15.6%). Smoking rates were higher among men than women with asthma (35.7% vs. 22.6%). Patients diagnosed with asthma were also more likely to be obese (BMI ≥ 30) than patients with ID but no asthma (42.7% vs. 31.6%). Obesity was particularly a problem among women with asthma as more than half (52.1%) had a BMI ≥ 30.

Conclusions  A very high proportion of patients with ID and asthma were found to be current smokers and/or obese. There is now strong research evidence that both smoking and obesity are implicated in the development of asthma and associated with worse disease outcomes. This study highlights the urgent need for programmes aimed at providing support for people with ID and asthma to stop smoking and to achieve a healthy body weight.
A socioenvironmental composite index as a tool for identifying urban areas at risk of lymphatic filariasis
Authors: Bonfim C. , Netto M. J. E. , Pedroza D. , Portugal J. L. , Medeiros Z.
Published: July 2009

Objective  To describe the spatial distribution of lymphatic filariasis and its relationship with the socioenvironmental risk indicator, thus identifying priority localities for interventions in endemic urban areas.

Methods  The study area was the municipality of Jaboatão dos Guararapes, State of Pernambuco, Brazil. The data sources were a parasitological survey and the 2000 demographic census. From these data, a socioenvironmental composite risk indicator was constructed using the 484 census tracts (CT) as the analysis units, based on the score‐formation technique. Census tracts with higher indicator values presented higher risk of occurrences of filariasis.

Results  Six thousand five hundred and seven households were surveyed and 23 673 individuals were examined, among whom 323 cases of microfilaremia were identified. The mean prevalence rate for the municipality was 1.4%. The indicator showed that 73% (237/323) of the cases of microfilaremia were in high‐risk areas (third and fourth quartiles) with worse socioenvironmental conditions (RR = 4.86, CI = 3.09–7.73, P < 0.05).

Conclusions  The socioenvironmental composite risk indicator demonstrated sensitivity, since it was able to identify the localities with greater occurrence of infection. Because it can stratify spaces by using official and available data, it constitutes an important tool for use in the worldwide program for eliminating lymphatic filariasis.
Proteinuria >0.5 g/d, a prevalent prognostic factor for patient and graft survival in kidney transplantation
Authors: Cantarovich Félix , Martinez Frank , Heguilen Ricardo , Thervet Eric , Mamzer‐Bruneel Marie‐France , Gonzalez Claudio , Legendre Christophe
Published: July 2009

Cantarovich F, Martinez F, Heguilen R, Thervet E, Mamzer Bruneel M‐F, Gonzalez C, Legendre C. Proteinuria >0.5 g/d, a prevalent prognostic factor for patient and graft survival in kidney transplantation. Clin Transplant 2009 DOI: 10.1111/j.1399‐0012.2009.01043.x © 2009 John Wiley & Sons A/S.

Abstract:  Proteinuria >0.5 g/d (HP) and serum creatinine (Scr) >120 μmol/L (HSC) at three months, two and five yr were compared as prognostic factors in kidney transplantation. We retrospectively analyzed 454 first transplants (follow‐up: 100 ± 3.2 months). Donor/recipient age, sex, panel reactive antibody (PRA), HLA mismatches, cold ischemia time, delayed graft function, acute rejection, blood pressure and its treatment, diabetes and anti‐calcineurin use were also evaluated. Cox proportional hazard regression with time‐dependent covariates to control for potentially confounding factors was used to analyze survival. The Kaplan–Meier product–limit estimate for survival according to urine protein excretion (≤ or >0.5 g/d) or Scr (≤ or >120 μmol/L) along with the log‐rank test for all comparisons were computed. Statistical significance was set with p‐value < 0.05.

Results:  HSC is a prognostic factor of graft survival (HR: 2.54; 95% CI: 1.98–3.10; p < 0.01) only at five yr, but it does not predict mortality at any period. HP at three months (HR: 2.07; 95% CI: 1.70–2.43; p < 0.001) and at two yr 3.03 (2.54–3.51; p < 0.001) significantly predicts graft failure. HP at two yr is the prevailingly prognostic factor of patient survival in kidney transplantation (HR: 3.30; 95% CI: 1.94–5.62; p < 0.0001).
The HLA‐G 14 bp insertion/deletion polymorphism is a putative susceptible factor for active human cytomegalovirus infection in children
Authors: Zheng X.‐Q. , Zhu F. , Shi W.‐W. , Lin A. , Yan W.‐H.
Published: July 2009

Human leukocyte antigen‐G (HLA‐G) expression is a potential factor for the pathogenesis of virus infection. A 14 bp insertion/deletion polymorphism (rs16375) in the 3′‐untranslated region of the HLA‐G gene is involved in the stability of HLA‐G mRNA and HLA‐G protein expression. Therefore, the HLA‐G 14 bp polymorphism might be involved in human cytomegalovirus (hCMV) infection. To test a possible association between the HLA‐G 14 bp deletion/insertion polymorphism and the active hCMV infection, in this study, a total of 54 patients with active hCMV infection and 165 age‐ and sex‐matched, unrelated, normal Chinese Han population were genotyped for the 14 bp insertion/deletion polymorphism. Association of 14 bp polymorphism with hCMV urine DNA copies and the odds ratio (OR) of the polymorphism as a risk factor for active hCMV infection were analyzed. Our results showed that the prevalence of −14 bp/ −14 bp genotype in active hCMV patients was markedly increased [Pc = 0.00034, OR = 3.31, 95% confidence interval (CI): 1.77–6.18], and similar significance was also observed for the frequency of −14 bp allele (P c = 0.0023, OR = 2.24, 95% CI: 1.38–3.64) when compared with that of healthy controls. Furthermore, urine hCMV DNA copies in patients with the −14 bp/ −14 bp genotype were significantly higher than those in patients with the +14 bp/ +14 bp genotype (P = 0.041). Our findings support a potential role of HLA‐G 14 bp insertion/deletion polymorphism as a susceptible factor for the active hCMV infection.
Relationship between statistical thermal alteration index and vitrinite reflectance for sedimentary rocks in northern Japan with reference to effects for unconformity, faulting, and contact metamorphism
Authors: Ujiié Yoshihiro
Published: July 2009

Two organic maturity indices, the statistical thermal alteration index (stTAI) and vitrinite reflectance (RO), are used to gain insight into the geological histories of sequences of Tertiary and Upper Cretaceous sediments in northern Japan that contain an unconformity and which are affected by faulting and contact metamorphism. The stTAI is based on the brightness, or gray level, of fossil pollen of Pinus, Podocarpus, Abies, and Picea species. Pollen brightness is measured using a transmitted‐light microscope equipped with a computer‐driven digital image processor. The stTAI represents the mean value of the modes for the complete array of indigenous pollen in rock samples. The stTAI indicates the level of organic maturation for Neogene sedimentary rocks of Japan, from incipient diagenesis to early catagenesis (RO ≤1.0%). With the progressive diagenesis and catagenesis of sedimentary rocks, stTAI values generally show a progressive decrease, whereas RO values increase. The effects of an unconformity and faulting are more clearly recorded in stTAI trends than in RO trends. During early stages of organic maturation (RO ≤0.7%), stTAI shows a rapid decrease, while RO shows a rapid increase during the mature and post‐mature stages (RO ≥0.8%). The occurrence of a range in RO values for a given level of organic maturity makes it difficult to determine the influence of the unconformity on the increasing RO trend. RO values show a progressive increase toward an igneous dyke, but this trend is not apparent in stTAI values. Measurements of Tertiary and Upper Cretaceous rocks in Japan reveal that stTAI is more sensitive to heating duration than RO, although RO is more sensitive to heating temperature.
Correlations among self‐esteem, aggression, adverse childhood experiences and depression in inmates of a female juvenile correctional facility in Japan
Authors: Matsuura Naomi , Hashimoto Toshiaki , Toichi Motomi
Published: July 2009

Aim:  The purpose of this study was to examine the following hypothesis: (i) Self‐esteem and aggressiveness, adverse childhood experiences (ACE), and a depressive tendency interact with each other. (ii) The subjects show a strong depressive tendency, and each of the other factors exerts a main effect on, and interacts with, the depressive tendency.

Method:  The subjects were 91 juveniles (all female) admitted to a female juvenile correctional facility between November 2005 and December 2006. They were aged 15–19 years, with a mean age of 17.0 (SD = 1.18) years. Self‐esteem scale, aggression scale, ACE questionnaire, and depression scale were conducted.

Results:  Significant main effects (R2 = 0.50, P < 0.001) on the depression score were observed in self‐esteem (β = −0.41, P < 0.001) and aggression (β = 0.21, P < 0.05). Self‐esteem, aggression, ACE, and depression were found to be interrelated.

Conclusion:  Low self‐esteem was also shown to exert marked effects on various factors. About half of the inmates of the facility were depressed, and the main effects of self‐esteem, aggression, and the ACE score were shown to influence the depression score.