bluuebunny/crossref_metadata_2025 huggingface dataset:
Implication from Randomized Trials of Rate and Rhythm Controls on Management of Patients with Persistent Atrial Fibrillation
Authors: Hagens Vincent E. , Van Veldhuisen Dirk J. , Crijns Harry J. G. M. , Van Gelder Isabelle C.
Published: March 2006

Recently, several randomized trials were published on the issue of rate or rhythm control for patients with atrial fibrillation (AF). Patients were typically minor symptomatic, relatively old, with age above 70, presenting with a recurrence of AF and suffering from only mild to moderate underlying heart disease. The main outcome of these trials is that rate control is not inferior to rhythm control for the management of patients with AF concerning morbidity and mortality. Also patients' quality of life did not differ significantly in follow‐up in these trials. However, rhythm control is not redundant in the treatment of AF. Focus is now on subgroups of patients who could still have benefit being in sinus rhythm. For severely symptomatic patients, patients presenting with the first episode of AF and probably those with severe congestive heart failure, to restore and maintain sinus rhythm should still be the goal. With the failure of antiarrhythmic therapy, nonpharmacological approaches such as pulmonary vein isolation can be performed.

Another finding of the randomized trials is that being in sinus rhythm does not prevent from the occurrence of thromboembolic complications. This means that for patients with AF, with risk factors for thromboembolic events, adequate anticoagulant therapy is indicated irrespective of the current heart rhythm. As with antiarrhythmic therapy, the search for new and safer anticoagulant therapy is underway.

This review will focus on the key aspects we have learned from the randomized trials on rate and rhythm controls for patients with AF.
Modality options for renal replacement therapy: The integrated care concept revisited
Authors: NESRALLAH Gihad , MENDELSSOHN David C.
Published: March 2006

As the End‐stage renal disease population continues to grow, innovative strategies that optimize patient outcomes while capitalizing on the relative strengths of the existing modalities must be sought. Renal transplantation remains the preferred form of renal replacement therapy, but given the limited supply of donor organs, dialytic therapies will continue to constitute a large part of the modality mix. Matching patients to the most suitable modalities requires that a number of factors be considered. These include the patient's autonomy, medical and social factors, system‐related issues, patient outcomes, and finances. While peritoneal dialysis and hemodialysis (HD) have traditionally been viewed as competing modalities, we propose that they, along with home and frequent HD regimens, may be used in a complementary manner, which is based on current evidence, and may provide optimal outcomes while containing treatment costs. In this review, we attempt to synthesize the current literature describing the various issues that affect modality selection, and offer an approach to achieving a balance between these many competing factors.
Gabapentin‐induced coma in a patient with renal failure
Authors: DOGUKAN Ayhan , AYGEN Bilge , BERILGEN Muhammed S. , DAG Sait , BEKTAS Sevim , GUNAL Ali İ.
Published: March 2006

We describe a 60‐year‐old woman who became comatose after a single dose of gabapentin for right‐sided sciatalgia. The patient was improved by hemodialysis. Gabapentin toxicity should be considered when mental status changes develop in patients with renal failure after even a single dose.
Verapamil and mild hyperkalemia in hemodialysis patients: A potentially hazardous association
Authors: LETAVERNIER Emmanuel , COUZI Lionel , DELMAS Yahsou , MOREAU Karine , MURCOTT Olivier , de PRÉCIGOUT Valérie
Published: March 2006

During the past 3 years, 3 patients undergoing intermittent hemodialysis (or about to do so) in our hospital developed a third‐degree atrioventricular block while being treated with verapamil for blood pressure or supraventricular arrhythmia. In the 3 cases, mild hyperkalemia was concomitant. The medical history of these patients revealed no intrinsic cause of atrioventricular conduction disturbance. We report herein the 3 cases and draw attention to the risks of atrioventricular block in this particular context.
Evaluation of primary failure in native AV‐fistulae (early fistula failure)
Authors: OHIRA Seiji , KON Tadamasa , IMURA Takashi
Published: March 2006

The most preferable method of vascular access (VA) in maintenance hemodialysis is a native arteriovenous fistula (AVF). Advanced age as well as the rapid increase in underlying diseases such as diabetic nephropathy and nephrosclerosis in these patients also means that the veins and arteries used to establish the AVF have undergone vascular damage, making construction of an AVF more difficult compared with earlier construction. Although there are various conditions under which arterial superficialization or AV graft must be chosen, it remains the rule that the first choice for VA should be AVF whenever possible. To improve postoperative results, it is necessary to reduce malfunctions immediately following surgery. We conducted a survey of 23 dialysis facilities throughout Japan and analyzed data from the past 3 years regarding the functionality of the AVF at initial puncture following construction of 5007 examples of newly constructed AVFs. Upon initial puncture, primary failure (PF) is defined as those cases in which thrombosis or inadequate blood flow occur. Primary failure occurred in 7.6% of the cases in this series, but there was a wide distribution of PF, 0.8% to 23.6%, because of differences in quality among facilities. This difference in PF is probably affected by technical aspects, the main factor being the characteristics of the patient. Survey responses included: (1) vascular damage of the veins and arteries used in creating the AVF and (2) the suitability of the location chosen for construction. In the data collected, many methods were used to repair those primary AFVs in which PF occurred. The salvage rate was 70%. Currently, the most preferable form of VA is AVF adhering to the principle that the proper timing of the choice and construction of AVF should consider the maturation period. To accomplish this, it is vital that vascular mapping be performed preoperatively to construct the AVF. If PF does occur, the cause should be thoroughly investigated and repairs made effectively.
Large variations in prescriptions of gastrointestinal medications in hemodialysis patients on three continents: The Dialysis Outcomes and Practice Patterns Study (DOPPS)
Authors: BAILIE George r. , MASON Nancy a. , ELDER Stacey j. , ANDREUCCI Vittorio e. , GREENWOOD Roger n. , AKIBA Takashi , SAITO Akira , BRAGG‐GRESHAM Jennifer l. , GILLESPIE Brenda w. , YOUNG Eric w.
Published: March 2006

Little is known about proton pump inhibitor (PPI) or H2 receptor antagonist (HA) prescription patterns or regarding use of predictors in hemodialysis patients. Proton pump inhibitor and HA prescribing patterns were investigated in 8628 hemodialysis patients from seven countries enrolled in the prospective, observational Dialysis Outcomes and Practice Patterns Study. Logistic regression examined predictors associated with PPI and HA use, adjusting for age, sex, country, time with end‐stage renal disease, medications, 14 comorbid conditions, and the association between the number of comorbid conditions and the prescription of gastrointestinal (GI) medications. In a cross‐section from February 1, 2000, 3.4% to 36.9% of patients received an HA and 0.8% to 26.9% took a PPI, depending upon the country. From 1996 to 2001, the prescription of HAs declined while PPI use increased. Facility use of HAs and PPIs ranged from 0% to 94% of patients. H2 receptor antagonist or PPI use was significantly and independently associated with age, narcotic use, corticosteroids, acetaminophen, nonsteroidal anti‐inflammatory drugs, tricyclic antidepressants, selective serotonin reuptake inhibitors, coronary artery disease history, cardiovascular diseases other than hypertension or congestive heart failure, peripheral vascular disease, pulmonary disease, and GI bleed. Proton pump inhibitors or HAs were more likely to be prescribed in Italy, Spain, and the United Kingdom than in the United States. The odds of PPI prescription increased if serum phosphorus <5.5 mEq/L or serum albumin <3.5 g/dL. Prescription of GI medications was associated with many comorbidities and use of several medications. Extreme variability of prescription patterns suggests that there is no standard approach in treatment practices.
Cromolyn sodium: A potential therapy for uremic pruritus?
Authors: ROSNER Mitchell H.
Published: March 2006

Uremic pruritus occurs in up to 50% of patients undergoing chronic hemodialysis. The pathogenesis of this disabling condition is unknown but likely involves multiple pathways involving the peripheral and central nervous system as well as local chemical and inflammatory mediators. Therapy has involved modification of the dialysis procedure, topical medications such as emollients, physical treatments such as ultraviolet light, and several oral medications such as antihistamines, activated charcoal, and gabapentin. Unfortunately, most of these therapies have not been subjected to rigorous clinical trials and clinical success has been variable. Two patients with disabling uremic pruritus refractory to multiple interventions are reported, who showed significant improvement in pruritus severity as assessed by a visual analog scale when they were treated with the mast cell stabilizer cromolyn sodium. Cessation of cromolyn resulted in return of pruritus, which improved with rechallenge with the medication. Cromolyn sodium may offer an alternative therapy for patients with refractory uremic pruritus, and should be subjected to a randomized placebo‐controlled trial.
The salvage of aneurysmal fistulae utilizing a modified buttonhole cannulation technique and multiple cannulators
Authors: MARTICORENA Rosa M. , HUNTER Joyce , MACLEOD Stephen , PETERSHOFER Elizabeth , DACOURIS Niki , DONNELLY Sandra , GOLDSTEIN Marc B.
Published: March 2006

We describe the St Michael's Hospital (SMH) modified buttonhole (BH) cannulation technique as a method that offers a solution for fistulae with aneurysmal dilatation due to repetitive cannulation in a restricted area. This is a prospective cohort study of 14 chronic hemodialysis (HD) patients with problematic fistulae (marked aneurysmal formation and thinning of the overlying skin, bleeding during treatment, and prolonged hemostasis post‐HD) because of repetitive, localized cannulation. Each patient was followed for 12 months. The protocol was as follows: creation of tunnel tracks by 1 to 3 experienced cannulators per patient, using sharp needles. After the tunnel tracks were established and cannulation was easily achieved with dull needles, additional cannulators were incorporated with the guidance of a mentor. Bleeding from cannulation sites during dialysis ceased within 2 weeks and skin damage resolved within 6 months in all patients. Hemostasis time postdialysis decreased from 24 to 15 min. Cannulation pain scores decreased significantly. Access flows and dynamic venous pressure measurements remained unchanged. No interventions were required to maintain access patency. In 2 cases, the aneurysms became much less evident. Complications included one episode of septic arthritis and one contact dermatitis. A third patient developed acute bacterial endocarditis 9 months following completion of her follow‐up. The SMH modified BH cannulation technique can salvage problematic fistulae, prevent further damage, and induce healing of the skin in the areas of repetitive cannulation. This technique can be successfully achieved by multiple cannulators in a busy full‐care HD unit.
Does an alteration of dialyzer design and geometry affect biocompatibility parameters?
Authors: OPATRNÝ Karel , KROUZŽECKÝ Aleš , POLANSKÁ Kamila , MAREŠ Jan , TOMŠŮ Martina , BOWRY Sudhir K , VIENKEN Jörg
Published: March 2006

The aim of the study was to assess the biocompatibility profile of a newly developed high‐flux polysulfone dialyzer type (FX‐class dialyzer). The new class of dialyzers incorporates a number of novel design features (including a new membrane) that have been developed specifically in order to enhance the removal of small‐ and middle‐size molecules. The new FX dialyzer series was compared with the classical routinely used high‐flux polysulfone F series of dialyzers. In an open prospective, randomized, crossover clinical study, concentrations of the C5a complement component, and leukocyte count in blood and various thrombogenicity parameters were evaluated before, and at 15 and 60 min of hemodialysis at both dialyzer inlet and outlet in 9 long‐term hemodialysis patients using the FX60S dialyzers and, after crossover, the classical F60S, while in another 9 patients, the evaluation was made with the dialyzers used in reverse order. The comparison of dialyzers based on evaluation of the group including all procedures with the FX60S and the group including procedures with the F60S did not reveal significant differences in platelet count, activated partial thromboplastin times, plasma heparin levels, platelet factor‐4, D‐dimer, C5a, and leukocyte count at any point of the collecting period. Both dialyzer types showed a significant increase in the plasma levels of the thrombin‐antithrombin III complexes; however, the measured levels were only slightly elevated compared with the upper end of the normal range. Biocompatibility parameters reflecting the behavior of platelets, fibrinolysis, complement activation, and leukopenia do not differ during dialysis with either the FX60S or the F60S despite their large differences in design and geometry features. Although coagulation activation, as evaluated by one of the parameters used, was slightly higher with the FX60S, it was still within the range seen with other highly biocompatible dialyzers and therefore is not indicative of any appreciable activation of the coagulation system. Thus, the incorporation of various performance‐enhancing design features into the new FX class of dialyzers does not result in a deterioration of their biocompatibility profile, which is comparable to that of the classical F series of dialyzers.
Determinants of metabolic acidosis among hemodialysis patients
Authors: SOUDAN Khaldoun , RICANATI Edmond S. , LEON Janeen B. , SEHGAL Ashwini R.
Published: March 2006

Metabolic acidosis is frequently present, poorly controlled, and associated with adverse effects among hemodialysis patients. Potential determinants of metabolic acidosis include endogenous acid production, administration of alkali, neutralization of acid by buffers, dilution of serum bicarbonate by interdialytic fluid gain, and loss of bicarbonate in stool. Understanding the relative importance of these determinants may help guide efforts to manage metabolic acidosis. We used chart abstraction, patient interviews, and laboratory testing to assess variables related to acid production (protein breakdown), alkali administration (dialysis dose, missed treatments, dialysate bicarbonate concentration, oral bicarbonate supplements), acid buffering (phosphorus binders), dilution of bicarbonate (interdialytic weight gain), and loss of bicarbonate in stool (diarrhea) for 190 randomly selected patients from 44 hemodialysis facilities. We used multivariate analyses to determine which potential determinants were independently associated with predialysis serum bicarbonate levels. Of all patients, 30% had metabolic acidosis (serum bicarbonate level <22 mEq/L). On multivariate analysis, metabolic acidosis was more likely with increased protein nitrogen appearance (odds ratio [OR] 1.60 per 0.2 g/kg/day, p=0.001) and less likely with increased Kt/V (OR 0.61 per 0.20 increase in Kt/V, p<0.001) and with increased calcium carbonate use (OR 0.38 per 2 g/day, p=0.003). Key determinants of metabolic acidosis among hemodialysis patients are protein breakdown, dialysis dose, and specific phosphorus binders. Further work is needed to develop interventions to address these determinants.
Microstructure and Dielectric Properties of a LaAlO3–TiO2 Diffusion Couple
Authors: Zhang Qinxin , McGinn Paul J.
Published: March 2006

Near‐field scanning microwave microscopy was applied to investigate the dielectric properties and microstructure in a polycrystalline LaAlO3–TiO2 diffusion couple, which included three regions containing different phases and microstructures. Relatively low (La2Ti4Al18O38), high (α‐La2/3TiO3), and intermediate (La4Ti9O24) dielectric constant phases were distinguished at the inter‐diffusion interface in optical, backscattered electron scanning electron microscopy, and scanning microwave microscopy (SMM) images. The relative ranking of dielectric constants based on SMM examination was as follows: TiO2>α‐La2/3TiO3>La4Ti9O24>LaAlO3>La2Ti4Al18O38. La2/3TiO3 and LaAlO3 will form solid solutions in the LaAlO3‐rich region. The reaction paths leading to phase development are discussed.
Novel Mullite Synthesis Based on Alumina Nanoparticles and a Preceramic Polymer
Authors: Bernardo Enrico , Colombo Paolo , Pippel Eckhard , Woltersdorf Jörg
Published: March 2006

Heating in air of a selected mixture of a silicone resin and alumina nanoparticles in the temperature range 1200°–1500°C yielded dense, crack‐free mullite samples. Al2O3, due to its nanometric size, proved to be very reactive toward silica, deriving from the ceramization of the preceramic polymer, leading to the formation of a large volume fraction of mullite crystals even at low firing temperatures (1250°C). Because of the homogeneity of the distribution of alumina nanoparticles in the starting system, the ceramized samples exhibited a very fine microstructure consisting of crystals with an average dimension in the range of 50–300 nm.
Surface Fractal Dimension of Perovskite‐Doped Alumina Membrane: Influence of Calcining Temperature
Authors: Ahmad A. L. , Idrus N. F. , Abd Shukor S. R.
Published: March 2006

The surface fractal dimension, D, and pore size distribution of perovskite‐doped alumina membrane prepared via the sol–gel method were determined from their nitrogen adsorption isotherms. The D value was calculated using the Frenkel–Halsey–Hill method. The D value increased with increasing temperature due to membrane shrinkage. The pore size distribution pattern of perovskite‐doped alumina membrane showed a narrow pore size when the temperature was increased from 400° to 800°C. The isotherm type was characterized as Type IV. Smoothing and sintering effects contributed to the decreasing trend of surface fractal dimension at a high temperature. The surface fractal dimension increased when the perovskite ratio in alumina membrane was increased.
Ferroelasticity andR‐Curve Behavior in BiFeO3–PbTiO3
Authors: Kounga Njiwa A. B. , Aulbach E. , Rödel J. , Turner S. L. , Comyn T. P. , Bell A. J.
Published: March 2006

Stress–strain curves of (1−x)BiFeO3–xPbTiO3compositions withx=0.2, 0.3, and 0.35 were determined under uniaxial loading to assess the material's potential for domain switching. The composition withx=0.35 provides the highest remanent strain, with more than 0.2% coupled with a strong tendency to relaxation. This ferroelastic behavior is in accordance with results fromR‐curve measurements on the same compositions, where the material with the most remanent strain yields the highest toughening effect.
Bounds To Texture Components In Superposed Crystallographic Textures
Authors: Jones Jacob L.
Published: March 2006

Crystallographic texture generates anisotropy that is essential to many advanced ceramic applications. For microstructures where texture components have resulted from unique material processes, the measured texture is a superposition of these independent texture components, making it difficult to characterize these unique processes independently. For superposed crystallographic textures comprised of both a random and a textured component, the volume fraction bounds of the randomly oriented texture component can be determined from the minimum value of the superposed orientation distribution function (ODF). In such textures, the maximum pole density of the textured component ODF is shown to be a function of the minimum and maximum values of the superposed ODF. An illustration of the formalism is given for a textured bismuth titanate ceramic.
Abnormal Grain Growth in Barium Titanate Doped with Alumina
Authors: Fisher John G. , Choi Si‐Young , Kang Suk‐Joong L.
Published: March 2006

The effect of additions of ≤1 mol% Al2O3 on abnormal grain growth in BaTiO3 sintered for periods of ≤60 min at 1350°C has been studied. Addition of ≤0.2 mol% Al2O3 caused an increase in the nucleation and growth rates of abnormal grains, with further additions causing a decrease. This behavior is explained by interface‐controlled growth. Dopant adsorption reduces both the edge free energy and the step velocity of a grain, causing the nucleation and growth rates of abnormal grains to increase, pass through a maximum, and then decrease with increasing dopant concentration.
FIB‐Nanotomography of Particulate Systems—Part I: Particle Shape and Topology of Interfaces
Authors: Holzer Lorenz , Muench Beat , Wegmann Markus , Gasser Philippe , Flatt Robert J.
Published: March 2006

A new 3D‐microscopy method, focused ion beam‐nanotomography (FIB‐nt), has been applied to the statistical particle shape analysis and for topological characterization of granular textures in cement samples. Because of its high resolution (15 nm), FIB‐nt reveals precise microstructural information at the submicrometer scale, which cannot be obtained with conventional tomography methods. It is demonstrated that even from complex granular textures with dense agglomerates, it is possible to identify the individual sub‐grains. This is the basis for reliable statistical shape analysis. For this purpose, moments of inertia were determined for particles from five different grain size fractions of a given cement, which provides important input data for future modeling of rheology and hydration processes. In addition, FIB‐nt was used for topological characterization of the particle–particle interfaces in the dense and fine‐grained granular textures. The unique 3D‐data obtained with FIB‐nt thus open new possibilities for quantitative microstructure analysis and the data can be used as structural input for object‐oriented modeling.
Effect of Co‐Precipitation on the Low‐Temperature Sintering of Biphasic Calcium Phosphate
Authors: Jun Youn‐Ki , Hong Seong‐Hyeon , Kong Young‐Min
Published: March 2006

Three types of biphasic calcium phosphate (BCP) powders were prepared and their sintering behavior was investigated. The specific surface area and HA/TCP ratio were similar in all three specimens. Most of the densification in the co‐precipitated s‐BCP occurred before the β‐ to α‐TCP phase transformation, and a maximum density of ∼95% was obtained at 1100°C. The mixture of separately precipitated and calcined hydroxyapatite (HA) and tricalcium phosphate (TCP) (m‐BCP) showed a poor sintering behavior, and the apparent density was below 70% at temperatures up to 1200°C. In the commercial HA and TCP mixture (c‐BCP), the low temperature sintering was poor, but densification continued without the phase transformation due to the presence of MgO, achieving almost full densification at 1200°C.
Ordered Ceramic Microstructures from Butterfly Bio‐template
Authors: Li Bo , Zhou Ji , Zong Ruilong , Fu Ming , Bai Yang , Li Longtu , Li Qi
Published: March 2006

Ordered lead lanthanum zirconate titanate (PLZT) structures with micrometer and submicrometer periods were created by an impressing sol–gel process, in which PLZT was used as the ceramic precursor and various butterfly wings were used as biological templates. It is a simple, inexpensive, and lithography‐free method for fabricating two‐dimensional‐ordered microstructures using natural biological templates, which can be used to study the periodic submicrometer dimension effect and photonic bandgap property of functional ceramics.
Thermoelectric Power in Nonstoichiometric Orthorhombic Titanium Oxides
Authors: Tsuyumoto Isao , Hosono Taisuke , Murata Masataka
Published: March 2006

Nonstoichiometric orthorhombic titanium oxides (TiOx; x=1.86–1.94) prepared by reducing the anatase titanium oxide in H2 at 950°C are found to show large thermoelectric power. Their Seebeck coefficients are in the range −0.060 to −0.518 mV/K, and theoretical discussions are made based on the assumption that the electronic spin entropy dominating the entropy current is a main factor of the thermoelectric power. The figure of merit for TiO1.94 at 70°C is estimated at 0.195. The nonstoichiometric orthorhombic titanium oxides, containing no hazardous elements, are promising materials for thermoelectric power generation.
A Novel Method for Fabrication of Y2O3‐Stabilized ZrO2 Electrolyte Films
Authors: Zhang Yaohui , Huang Xiqiang , Lu Zhe , Liu Zhiguo , Ge Xiaodong , Xu Jiahuan , Xin Xianshuang , Sha Xueqing , Su Wenhui
Published: March 2006

Gas‐tight Y2O3‐stabilized ZrO2 (YSZ) films were prepared on NiO–YSZ and NiO–SDC (Sm0.2Ce0.8O1.9) anode substrates by a novel method. A cell, Ni–YSZ/YSZ(10 μm)/LSM–YSZ, was tested with humidified hydrogen as fuel and ambient air as oxidant. The maximum power densities of 1.64, 1.40, 1.06, and 0.60 W/cm2 were obtained at 850°, 800°, 750°, and 700°C, respectively. With methane as fuel, a cell of Ni–SDC/YSZ (12 μm)/LSM–YSZ exhibited the maximum power densities of 1.14, 0.82, 0.49, and 0.28 W/cm2 at 850°, 800°, 750°, and 700°C, respectively. The impedance results showed that the performance of the cell was controlled by the electrode polarization rather than the resistance of YSZ electrolyte film.
Strong Suppression and Enhancement of Photoluminescence in Zn2SiO4:Mn2+ Inverse Opal Photonic Crystals
Authors: Li Bo , Zhou Ji , Zong Ruilong , Fu Min , Li Longtu , Li Qi
Published: March 2006

Inverse opal photonic crystals based on a luminescent matrix of Mn2+‐doped Zn2SiO4 were synthesized, and their photoluminescence was investigated using a fluorescence microscope and spectrometer. Strong suppression of the luminescence from the Zn2SiO4:Mn2+ matrix in certain directions was observed directly due to the overlap of the pseudo‐photonic bandgap (PPBG) and the emission band. As a result, the luminescence in other orientations (outer of the PPBG) was enhanced significantly. This cost‐effective, non‐lithographic method to produce luminescent inverse opals is expected to be useful for the fabrication of anisotropic photonic crystal light sources for display applications.
Synthesis and Characterization of BaTi1−xGaxO3−δ (0x0.15) Ceramics
Authors: Feteira Antonio , Sinclair Derek C. , Reaney Ian M.
Published: March 2006

The crystal structure type, ceramic microstructures, and dielectric properties of BaTi1−xGaxO3−δ (BTG) (0x0.15) ceramics prepared by the mixed oxide route have been investigated. X‐ray diffraction shows the room‐temperature crystal structure of BTG changes from tetragonal (t‐BT; space group P4mm) to hexagonal (h‐BT; space group P63/mmc) at x∼0.04. These results are also confirmed by electron diffraction and dielectric measurements. For x>0.12, a secondary phase isostructural with Ba2TiO4 is detected. Scanning electron microscopy (SEM) reveals three distinctive ceramic microstructures dependent on the firing temperature. BTG compacts fired at 1350°C consist of fine (2–3 μm) equiaxed grains within a narrow grain size distribution, whereas either large anisotropic or large (100–300 μm) rounded grains embedded in a fine‐grained matrix are observed for ceramics fired at 1400° and 1450°C, respectively. Transmission electron microscopy (TEM) of BTG (x=0.04) ceramics reveals some grains exhibiting both ferroelectric domains and stacking faults, which appear absent in ceramics with x≥0.06. Ga‐enriched grain boundaries were also revealed by energy dispersive spectroscopy (EDS) analysis. Dielectric measurements show the room‐temperature relative permittivity, ɛr, for x≤0.03 to be ∼1500–2000 and that the Curie Temperature, Tc, decreases at a rate ∼8 K/at.%, whereas the room‐temperature ɛr for h‐BTG with x≥0.06 decreases continuously with x from ∼80 to ∼65. h‐BTG ceramics show a strong decrease in ɛr with increasing temperature in the range 125–425 K, suggesting the possibility of a phase transition below 125 K.
A Representative Volume Element for the Densification of Powders
Authors: Krishnan Kumar , Slaughter William S. , McAfee Richard J. , Nettleship Ian
Published: March 2006

Previous studies have shown that the traditional phenomenological models of sintering contain pores that are generally too small and too numerous to represent the microstructural evolution of alumina ceramics at temperatures below 1400°C. In this study a representative volume element was simulated by the random placement of 1000 non‐overlapping spheres, which was subsequently densified by contact flattening. The resulting dimensionless microstructural pathway based on the fraction of solid‐solid surface showed very good agreement with experimental results for alumina sintered at 1350°C. Increasing the width of the sphere size distribution for this simulation had little effect on the chosen dimensionless microstructural pathway.
Microstructure and Thermal Shock Resistance of Molten Glass‐Coated Carbon Materials Fabricated by Interfacial Control
Authors: Wada Masashi , Kitaoka Satoshi , Kawashima Naoki , Yamada Tatsuya , Yasutomi Yoshiyuki , Kawai Masatoshi , Inagaki Hideki
Published: March 2006

Carbon substrates were coated completely with a molten silicate glass, where the wettability of carbon to glass was improved by infiltration and pyrolysis of perhydropolysilazane. Microstructures of the carbon–glass interface were dependent on Pn2 during coating. Coating at lower Pn2 induced the formation of cristobalite at the carbon–glass interface. When the coating was performed at higher Pn2, the glass and carbon were strongly adhered, without the formation of cristobalite. Coating at higher Pn2 improved the thermal shock resistance of the glass layer, because crack initiation was not induced by the phase transformation of cristobalite during the cooling process. In the case of coating at higher Pn2, an oxynitride glass layer was formed at the glass subsurface by dissolution of N2. A porous glass subsurface layer with uniform spherical micro‐pores could be produced by soaking near the glass transition temperature in a steam environment. The porous layer with fine and homogeneous microstructure acts as a thermal shock absorbing layer, so that glass‐coated carbon with a porous glass layer has excellent thermal shock resistance in addition to steam oxidation resistance.
Effect of Varying Quartz Particle Size and Firing Atmosphere on Densification of Brazilian Clay‐Based Stoneware
Authors: Souza G. P. , Messer P. F. , Lee W. E.
Published: March 2006

Body mixes for stoneware containing a Brazilian red clay, nepheline syenite, and quartz with two different median particle sizes (∼2 and 18 μm) were fired under oxidizing and reducing atmospheres. The densification behavior was followed by dilatometry simulating the firing schedule, as well as by water absorption, linear shrinkage, and bulk density measurements on as‐fired specimens. It was revealed that finer quartz led to interconnected pore closure at 1125°C when fired under an oxidizing atmosphere. Densification was systematically related to the uniformity of the compacts in the unfired state. Phase and microstructural examination by X‐ray diffractometry, scanning electron microscopy/energy‐dispersive spectroscopy (EDS), and transmission electron microscopy/EDS showed that mullite developed more extensively in the stonewares fired in an oxidizing atmosphere, along with cristobalite and haematite, whereas metallic iron was found in stonewares fired under a reducing atmosphere.
Sintering and Electrical Properties of Lead‐Free Na0.5K0.5NbO3 Piezoelectric Ceramics
Authors: Zuo Ruzhong , Rödel Jürgen , Chen Renzheng , Li Longtu
Published: March 2006

Lead‐free Na0.5K0.5NbO3 (NKN) piezoelectric ceramics were fairly well densified at a relatively low temperature under atmospheric conditions. A relative density of 96%–99% can be achieved by either using high‐energy attrition milling or adding 1 mol% oxide additives. It is suggested that ultra‐fine starting powders by active milling or oxygen vacancies and even liquid phases from B‐site oxide additives mainly lead to improved sintering. Not only were dielectric properties influenced by oxide additives, such as the Curie temperature (Tc) and dielectric loss (D), but also the ferroelectricity was modified. A relatively large remanent polarization was produced, ranging from 16 μC/cm2 for pure NKN to 23 μC/cm2 for ZnO‐added NKN samples. The following dielectric and piezoelectric properties were obtained: relative permittivity ɛT33/ɛ0=570–650, planar mode electromechanical coupling factor, kp=32%–44%, and piezoelectric strain constant, d33=92–117 pC/N.
Enhanced bone apposition around biofunctionalized sandblasted and acid‐etched titanium implant surfaces
Authors: Germanier Yves , Tosatti Samuele , Broggini Nina , Textor Marcus , Buser Daniel
Published: March 2006

Abstract: Microrough titanium (Ti) surfaces of dental implants have demonstrated more rapid and greater bone apposition when compared with machined Ti surfaces. However, further enhancement of osteoblastic activity and bone apposition by bio‐functionalizing the implant surface with a monomolecular adsorbed layer of a co‐polymer – i.e., poly(l‐lysine)‐graft‐poly(ethylene glycol) (PLL‐g‐PEG) and its derivatives (PLL‐g‐PEG/PEG‐peptide) – has never been investigated. The aim of the present study was to examine early bone apposition to a modified sandblasted and acid‐etched (SLA) surface coated with an Arg–Gly–Asp (RGD)‐peptide‐modified polymer (PLL‐g‐PEG/PEG–RGD) in the maxillae of miniature pigs, and to compare it with the standard SLA surface. Test and control implants had the same microrough topography (SLA), but differed in their surface chemistry (polymer coatings). The following surfaces were examined histomorphometrically: (i) control – SLA without coating; (ii) (PLL‐g‐PEG); (iii) (PLL‐g‐PEG/PEG–RDG) (RDG, Arg–Asp–Gly); and (iv) (PLL‐g‐PEG/PEG–RGD). At 2 weeks, RGD‐coated implants demonstrated significantly higher percentages of bone‐to‐implant contact as compared with controls (61.68% vs. 43.62%; P<0.001). It can be concluded that the (PLL‐g‐PEG/PEG–RGD) coatings may promote enhanced bone apposition during the early stages of bone regeneration.
Safety and tolerability of inhaled budesonide in children in the Steroid Treatment As Regular Therapy in early asthma (START) trial
Authors: Silverman Michael , Sheffer Albert L. , Díaz Patricia V , Lindberg Bengt
Published: March 2006

The safety and tolerability of asthma medications are still a concern to many asthma patients receiving long‐term treatment. Therefore, more safety data from long‐term, controlled trials are needed. The aim of this study was to evaluate the safety and tolerability of long‐term treatment with once‐daily budesonide in children aged 5–10 yrs with mild persistent asthma of recent onset in the inhaled Steroid Treatment As Regular Therapy in early asthma (START) study. Children aged 5–10 yrs with early asthma were randomized to double‐blind treatment with budesonide 200 μg or placebo once daily via TurbuhalerTM in addition to usual asthma therapy, for 3 yrs. Adverse events were recorded from both spontaneous reports and responses to standard questions, and asthma‐related events and asthma control were recorded between visits and subsequently graded by the blinded investigators. Of the study population of 1981 children (1004 budesonide and 977 usual care), 81% (812 of 1004) in the budesonide group and 82% (797 of 977) in the usual care group experienced a total of 6414 events listed by preferred term (3209 budesonide plus usual care and 3205 placebo plus usual care). The most commonly reported events included respiratory infection, pharyngitis, rhinitis, viral infection and bronchitis, and there were no clinically relevant differences in incidence between treatments. There were no reports of tuberculosis or aspergillosis, and no evidence of increased risk of systemic or ocular adverse events with budesonide relative to placebo. There were 106 serious adverse events in the budesonide group and 128 with usual care. The most frequent, aggravated asthma, was more common with usual care than with budesonide. There were no deaths among children participating in START. In conclusion, the addition of once‐daily inhaled budesonide 200 μg via TurbuhalerTM to usual care is safe and well tolerated in children with recent‐onset mild persistent asthma.
Cost‐effectiveness of early intervention with once‐daily budesonide in children with mild persistent asthma: results from the START study
Authors: Weiss Kevin , Buxton Martin , Andersson Fredrik L. , Lamm Carl‐Johan , Liljas Bengt , Sullivan Sean D.
Published: March 2006

The inhaled Steroid Treatment As Regular Therapy in early asthma (START) study has shown that early intervention with inhaled budesonide in mild persistent asthma improves clinical outcomes in both adults and children. The aim of this study was to estimate the incremental cost‐effectiveness of early treatment with budesonide Turbuhaler in children aged 5–10 yr who participated in START. Direct and indirect costs associated with asthma were determined for 1974 children participating in the double‐blind, 3‐year part of the study. Randomization was to placebo or to budesonide 200 μg once daily in each case in addition to usual asthma care. Cost‐effectiveness ratios were calculated from the healthcare payer's and societal perspectives (using US prices). The addition of once‐daily budesonide therapy to usual asthma care was associated with 16 additional symptom‐free days (SFDs) per child over the 3‐yr period (p < 0.001), with a substantial reduction (50%) in the mean number of days spent in hospital, and with reduced frequency of emergency room visits and missed school and caregiver work days. From the healthcare payer's perspective (direct costs), the increase in mean direct cost over 3 yr with budesonide was $169, which translated into an incremental cost of early intervention with budesonide in children of $10.50 (95% CI $1.20–33.30) per SFD gained. From the societal perspective, there was a cost reduction over 3 yr of $192 with budesonide relative to placebo. From a societal perspective, budesonide was therefore dominant. In conclusion, early intervention with once‐daily budesonide added to usual asthma care in children with mild persistent asthma is cost‐saving from a societal perspective and is acceptably cost‐effective when viewed from a healthcare payer perspective.
Prevalence and risk factors associated with geographic tongue among US adults
Authors: Shulman JD , Carpenter WM
Published: March 2006

Objective: To characterize the prevalence of geographic tongue (GT) among US adults.

Design: Population‐based case–control study

Main outcome measures: The presence or absence of GT.

Subjects and methods: Data from 16 833 adults examined during The Third National Health and Nutrition Examination Survey, 1988–1994 (NHANES III), a study based on multistage probability sampling were analyzed using SAS‐callable SUDAAN 9.0.1.

Results: Geographic tongue point prevalence was 1.8% (95% CI: 1.4, 2.3). Multivariate logistic regression showed significant effects of race‐ethnicity, with Whites (AOR = 1.8; 1.3, 2.5) and Blacks (AOR = 1.6; 1.2, 2.1) having greater odds of GT than Mexican‐Americans; current corticosteroid therapy (AOR = 3.7; 1.54, 8.6). Cigarette smokers had lower GT prevalence (AOR = 0.4; 0.3, 0.6). Fissured tongue (FT) was strongly associated with GT among non‐smokers: AOR = 17.5 (7.8, 39.5). We did not find significant associations with age, gender, oral contraceptive use, diabetes mellitus, allergy or atopy, psychological or dermatological conditions as previous research has suggested.

Conclusions: Geographic tongue was more prevalent among Whites and Blacks compared with Mexican‐Americans, positively associated with FT, and inversely associated with cigarette smoking.
Smokeless tobacco‐induced lamellar body abnormalities
Authors: Colvard MD , Ashrafi SH , Alonge OK , Cordell GA
Published: March 2006

Objectives:  To compare the morphological changes and quantitative distribution of lamellar bodies (Lb) (membrane coating granules) in the hamster cheek pouch epithelium with smokeless tobacco (ST).

Materials and methods:  Archives of experimental material from previously published studies [S. Ashrafi, A. Das, R. Worawongvasu, B. Mehdinejad and J. Waterhouse (1992) Scanning Microscopy6: 183] were utilized. Animals in experimental group received most ST (snuff) in their right pouch, 5 days weekly, for 24 months, while no snuff was given to control group. After 24 months, the epithelial tissues were processed for electron microscopic study. Volume densities of Lb were assessed by morphometry.

Main outcome measures:  Densities of Lb in the two groups, experimental vs control.

Results:  In the control, Lb extruded their contents into the intercellular spaces of upper granular layers and in between the last granular cell layers and keratin layers to form a permeability barrier. Conversely, in the smokeless tobacco‐treated epithelium, the majority of the Lb that were formed remained inside and accumulated within the granular cells, without extruding their contents into the intercellular spaces to form a lipid compound permeability barrier.

Conclusions:  Commercial alkaline ST may have contributed to the abnormal accumulation of Lb in the granular cell layer and affected the extrusion process of Lb to form an incomplete permeability barrier in the oral epithelium.
Independent quantitative trait loci influence ventral and dorsal hippocampal volume in recombinant inbred strains of mice
Authors: Martin Maureen V. , Dong Hongxin , Vallera Dana , Lee David , Lu Lu , Williams Robert W. , Rosen Glenn D. , Cheverud James M. , Csernansky John G.
Published: March 2006

Anatomical and functional studies support segregation of the hippocampus into ventral and dorsal components along its septotemporal axis. However, it is unknown whether the development of these two components of the hippocampus is influenced by common or separate genetic factors. In this study, we used recombinant inbred strains of mice to determine whether the same or different quantitative trait loci (QTL) influence ventral and dorsal hippocampal volume. Using two sets of strains of recombinant inbred mice (BXD and AXB/BXA), we identified separate QTLs for ventral and dorsal hippocampal volume. In BXD mice, suggestive QTLs for ventral hippocampus were identified on chromosomes 2, 8 and 13, and a significant QTL for dorsal hippocampal volume was identified on chromosome 15. There was also a suggestive QTL for dorsal hippocampal volume on chromosome 13. In AXB/BXA mice, there were no significant or suggestive QTLs for ventral hippocampal volume, but a significant QTL for dorsal hippocampus was identified on chromosome 5. These findings suggest that the development of the ventral and dorsal components of the hippocampus is influenced by separate genetic loci.
Estimating wall guidance and attraction in mouse free locomotor behavior
Authors: Horev G. , Benjamini Y. , Sakov A. , Golani I.
Published: March 2006

In this study, we estimate the influence exerted by the wall of the Open Field on the trajectory of the mouse. The wall exerts two types of influence on the mouse’s path: one of guidance and one of attraction. The guiding influence is expressed by the tendency of mice to progress in parallel to the wall. This tendency wanes with increasing distance from the wall but is observed at large distances from it. The more parallel the mouse is to the wall the higher is its speed, even when distant from the wall. This association between heading direction and speed shows that the mouse controls its heading in reference to the wall. It is also observed in some blind strains, revealing that wall‐guidance is not based exclusively on vision. The attraction influence is reflected by movement along the wall and by the asymmetry between speed during movement toward, and during movement away from the wall: sighted mice move faster toward the wall, whereas blind mice use similar speeds in both directions. Measures characterizing these influences are presented for five inbred strains, revealing heritable components that are replicable across laboratories. The revealed structure can lead to the identification of distinct groups of genes that mediate the distinct influences of guidance and attraction exerted by the wall. It can also serve as a framework for the decoding of electrophysiological data recorded in free moving rodents in the Open Field.
Roost Structure, Modification, and Availability in the White‐throated Round‐eared Bat,Lophostoma silvicolum(Phyllostomidae) Living in Active Termite Nests1
Authors: Kalko Elisabeth K. V. , Ueberschaer Katja , Dechmann Dina
Published: March 2006

We studied roost structure, modification, and availability inLophostoma silvicolum(Phyllostomidae), an insectivorous gleaning bat, on Barro Colorado Island (BCI), Panamá. Collection of nest material beneath termitaria and infrared video filming indicated that males ofL. silvicolumexcavate and maintain cavities inside active termite nests. A binary logistic regression analysis showed that to be suitable as roosts, termite nests have to be larger than 30 cm in diameter and taller than 30 cm, well shaded, with few transecting branches, and freely accessible from below. Use of active termite nests as roosts may provide several benefits toL. silvicolum, including reduction of competition for roost sites with sympatric bat species, reduced parasite load and a suitable microclimate. A comparison of number of all termite nests in selected forest plots with number of termite nests that are potentially suited as bat roosts and number of termite nests that are actually used by bats suggests thatL. silvicolummay not be roost‐limited on BCI in spite of its highly specialized roost choice.
Ants on the Move: Resource Limitation of a Litter‐nesting Ant Community in Costa Rica1
Authors: McGlynn Terrence P.
Published: March 2006

The leaf litter of tropical wet forests is replete with itinerant ant nests. Nest movement may help ants evade the constraints of stress and disturbance and increase access to resources. I studied how nest relocation and environmental factors may explain the density, size, and growth of leaf litter ant nests. I decoupled the relationships among litter depth, food abundance, and nest availability in a 4‐mo manipulation of food and leaf litter in a community of litter‐nesting ants in a lowland wet forest in Costa Rica. Over 4 mo, 290 1 m2treatment and control plots were sampled without replacement. Nest densities doubled in response to food supplementation, but did not decrease in response to litter removal or stress (from litter trampling). The supplementation of food increased the utilization of less favored nesting materials. In response to food supplementation and litter trampling, arboreal ants established nests in the litter, and growth rates of the most common ants (Pheidolespp.) increased. Colony growth was independent of colony size and growth rates of the most abundant ants. In general, I conclude that litter‐nesting ant density is driven primarily by food limitation, that nest relocation behavior significantly affects access to resource and the demographic structure of this community, and that nest fission may be a method to break the growth–reproduction trade‐off.