bluuebunny/crossref_metadata_2025 huggingface dataset:
Orexigenic Peptides and Alcohol Intake: Differential Effects of Orexin, Galanin, and Ghrelin
Authors: Schneider Eve R. , Rada Pedro , Darby Ryan D. , Leibowitz Sarah F. , Hoebel Bartley G.
Published: September 2007

Background:  The question is which hypothalamic systems for food intake might play a role in ethanol intake and contribute to alcohol abuse. The peptide orexin was found to exhibit similar properties to galanin in its relation to dietary fat and may therefore be similar to galanin in having a stimulatory effect on alcohol intake.

Methods:  Rats were trained to drink 10% ethanol, implanted with brain cannulas, and then injected in the paraventricular nucleus (PVN), lateral hypothalamus (LH), or nucleus accumbens (NAc) with galanin, orexin‐A, and for comparison, ghrelin. Ethanol, food, and water intake were measured at 1, 2, and 4 hours postinjection.

Results:  In the PVN, both orexin and galanin significantly increased ethanol intake, whereas ghrelin increased food intake. In the LH, orexin again induced ethanol intake, while ghrelin increased eating. In the NAc, orexin failed to influence ethanol intake but did stimulate food intake.

Conclusions:  In ethanol‐drinking rats, injection of orexin or galanin into the appropriate locus in the hypothalamus induced significant ethanol intake instead of food intake. Ghrelin, as a positive control, failed to influence ethanol intake at the same hypothalamic sites. In the NAc, as an anatomical control, orexin augmented eating but not ethanol intake. Thus orexin and galanin in the hypothalamus selectively stimulated ethanol intake at sites where other studies have shown that both ethanol and fat increase expression of the endogenous peptides. Thus, a neural circuit that evolved with the capability to augment food intake is apparently co‐opted by ethanol and may serve as a potential positive feedback circuit for alcohol abuse.
S‐Adenosylmethionine Attenuates Oxidative Liver Injury in Micropigs Fed Ethanol With a Folate‐Deficient Diet
Authors: Villanueva Jesus A. , Esfandiari Farah , White Mollie E. , Devaraj Sridevi , French Samuel W. , Halsted Charles H.
Published: September 2007

Background:  To demonstrate a causative role for abnormal methionine metabolism in the pathogenesis of alcoholic steatohepatitis (ASH), we measured the preventive effects of supplementing folate deficient and ethanol containing diets in the micropig with S‐adenosylmethionine (SAM), a metabolite that regulates methionine metabolism.

Methods:  Yucatan micropigs were fed folate‐deficient diets as control, with ethanol at 40% of kcal, or with ethanol supplemented with SAM at 0.4 g/1000 kcal for 14 weeks. Histopathology, markers of liver injury, and regulatory enzymes were measured in terminal liver samples.

Results:  Among the ethanol group, livers showed hepatocellular necrosis together with increased levels of S‐adenosylhomocysteine (SAH) and reduced levels of SAM and its ratio to SAH and glutathione (GSH), together with increased malondialdehyde plus hydroxynonenol (MDA + HNE) and nitrotyrosine (NT), transcripts and protein levels of cytochrome P4502E1 (CYP2E1), activity of NADPH oxidase, and activity and protein levels of inducible nitric oxide (iNOS). These findings were attenuated partially or completely to control levels by SAM supplementation of the ethanol diet.

Conclusions:  The present results indicate that SAM supplementation attenuates ethanol induced liver injury through its effects on the expressions and activities of oxidative stress pathways, and are consistent with the concept that the pathogenesis of oxidative liver injury is regulated in part through altered hepatic methionine metabolism.
Lysosomal Leakage and Lack of Adaptation of Hepatoprotective Enzyme Contribute to Enhanced Susceptibility to Ethanol‐Induced Liver Injury in Female Rats
Authors: Donohue Terrence M. , Curry‐McCoy Tiana V. , Nanji Amin A. , Kharbanda Kusum K. , Osna Natalia A. , Radio Stanley J. , Todero Sandra L. , White Ronda L. , Casey Carol A.
Published: September 2007

Background:  Women exhibit greater liver damage than men after chronic alcohol consumption. Similar findings are reported in animal models. Here, we determined whether differential liver injury occurred in male and female rats after feeding these animals liquid diets containing either ethanol or isocaloric dextrose with fish oil as the sole source of lipid.

Methods:  Control and ethanol liquid diets containing fish oil were pair‐fed to male and female rats for 8 weeks. Liver damage was evaluated by triglyceride accumulation, lipid peroxide formation, serum transaminases, histological evaluation, and the activities of selected lysosomal and hepatoprotective enzymes.

Results:  Fatty liver was detected after ethanol feeding in both genders, but in female rats, triglyceride levels were 60% higher, lipid peroxides were 2‐fold higher, and inflammatory cells were more evident than in males. A 2‐fold elevation of cathepsin B in hepatic cytosol fractions, indicating lysosomal leakage, was detected in ethanol‐fed female rats but no such elevation was observed in males. The basal activity of the hepatoprotective enzyme, betaine‐homocysteine methyltransferase was 4‐fold higher in livers of control male rats than females, and the enzyme activity was further elevated in ethanol‐fed male rats but not in females.

Conclusions:  Thus, female rats given ethanol in a diet containing fish oil exhibited more severe liver damage than males. We propose that this difference results, in part, from a greater tendency by females to accumulate hepatic fat, thereby enhancing the potential for oxidative stress, which in turn leads to hepatic inflammation. In addition, our findings indicate that female rats have a higher susceptibility to liver damage because of a reduced capacity for hepatoprotection.
Real‐Time Model Uncertainty in the United States: The Fed, 1996–2003
Authors: TETLOW ROBERT J. , IRONSIDE BRIAN
Published: September 2007

We study 30 vintages of FRB/US, the principal macro‐model used by the Federal Reserve Board staff for forecasting and policy analysis. We document the surprisingly large and consequential changes in model properties that occurred during the period from July 1996 to November 2003 and compute optimal Taylor‐type rules for each vintage. Model uncertainty is shown to be a substantial problem; the efficacy of purportedly optimal policy rules should not be taken on faith. We also find that previous findings that simple rules are robust to model uncertainty may be an overly sanguine conclusion.
The Cost of Nominal Rigidity in NNS Models
Authors: CANZONERI MATTHEW B. , CUMBY ROBERT E. , DIBA BEHZAD T.
Published: September 2007

We present a model with Calvo wage and price setting, capital formation, and estimated rules for government spending and monetary policy. Our model captures many aspects of U.S. data, including the volatility that has been observed in various efficiency gaps. We estimate the cost of nominal rigidity—welfare under flexible wages and prices minus welfare with nominal rigidities—to be as much as 3% of consumption each period. Since there are interest rate rules that virtually eliminate this cost, our model suggests that—contrary to Lucas's (2003) assertion—there is considerable room for improvement in demand management policy.
Pricing Behavior and the Response of Hours to Productivity Shocks
Authors: MARCHETTI DOMENICO J. , NUCCI FRANCESCO
Published: September 2007

Recent contributions have suggested that technology shocks have a negative impact on hours, contrary to the prediction of standard flexible‐price models of the business cycle. Some authors have interpreted this finding as evidence in favor of sticky‐price models, while others have either extended flexible‐price models or disputed the empirical finding itself. In this paper, we estimate a variety of alternative total factor productivity measures for a representative sample of Italian manufacturing firms and on average find a negative effect of productivity shocks on hours growth. More interestingly, using the reported frequency of price reviews, we show that the contractionary effect is stronger for firms with stickier prices and weaker or not significant for firms with more flexible prices. Price stickiness remains a crucial factor in shaping the response of hours after controlling for product storability or market power.
A Generalized Extreme Value Approach to Financial Risk Measurement
Authors: BALI TURAN G.
Published: September 2007

This paper develops an unconditional and conditional extreme value approach to calculating value at risk (VaR), and shows that the maximum likely loss of financial institutions can be more accurately estimated using the statistical theory of extremes. The new approach is based on the distribution of extreme returns instead of the distribution of all returns and provides good predictions of catastrophic market risks. Both the in‐sample and out‐of‐sample performance results indicate that the Box–Cox generalized extreme value distribution introduced in the paper performs surprisingly well in capturing both the rate of occurrence and the extent of extreme events in financial markets. The new approach yields more precise VaR estimates than the normal and skewed t distributions.
Wealth and Risk Effects of Adopting Deposit Insurance in Canada: Evidence of Risk Shifting by Banks and Trust Companies
Authors: WAGSTER JOHN D.
Published: September 2007

This paper confirms that adopting explicit deposit insurance expanded risk‐shifting incentives for Canadian Banks and Trust Companies. By transferring responsibility for monitoring non‐systematic risk to the Canadian Deposit Insurance Corporation (CDIC), deposit insurance eliminated the compensation previously paid to large‐block stockholder monitors. This transfer fueled a redistribution of insured‐institution stock from poorly diversified large‐block shareholders to diversified investors. Also, subsequent changes in market volatility support the hypothesis that CDIC insurance and the absorption of catastrophic risk it provided reduced systematic risk in the stock market as a whole even as it increased non‐systematic risk in the banking and trust‐company sector.
Equilibrium Dynamics in an Endogenous Growth Model of Money and Banking
Authors: CHANG JUIN‐JEN , CHANG WEN‐YA , LAI CHING‐CHONG , WANG PING
Published: September 2007

We construct an analytically tractable endogenous growth model of money and banking where money provides “liquidity services” to facilitate transactions and banks convert non‐reserve deposits into productive capital. We examine both the long‐ and short‐run effects of changes in the money growth rate or the reserve requirement ratio. In response to a change in the required reserve ratio, the inflation rate and the growth rates of capital, real balances, and consumption need not adjust monotonically along the transition path. While the balanced growth equilibrium may be either a saddle or a source locally, the global dynamical system exhibits flip bifurcation.
Imperfect Common Knowledge, Staggered Price Setting, and the Effects of Monetary Policy
Authors: FUKUNAGA ICHIRO
Published: September 2007

This paper studies the consequences of a lack of common knowledge in the transmission of monetary policy by integrating the Woodford (2003a) imperfect common knowledge model with Taylor–Calvo staggered price‐setting models. The average price set by monopolistically competitive firms depends on their higher‐order expectations about not only the current state of the economy but also about the states in the future periods in which prices are to be fixed. This integrated model provides a plausible explanation for the observed effects of monetary policy: it shows analytically how price adjustments are delayed and how the response of output to monetary disturbances is amplified.
Optimality of the Friedman Rule in an Overlapping Generations Model with Spatial Separation
Authors: HASLAG JOSEPH H. , MARTIN ANTOINE
Published: September 2007

Recent models with spatial separation and limited communication suggest that the Friedman rule may not be optimal. This is important in light of the disparity between theory and practice concerning optimal monetary policy. We take a close look at these models and show that intergenerational transfers are key to the suboptimality of the Friedman rule. The Friedman rule is a necessary condition for achieving the efficient allocation in equilibrium. We also show that the Friedman rule is chosen whenever agents can implement mutually beneficial arrangements.
Optimal Fiscal Policy Rules in a Monetary Union
Authors: KIRSANOVA TATIANA , SATCHI MATHAN , VINES DAVID , WREN‐LEWIS SIMON
Published: September 2007

This paper investigates the importance of fiscal policy in providing macroeconomic stabilization in a monetary union. We use a microfounded New Keynesian model of a monetary union, which incorporates persistence in inflation and non‐Ricardian consumers, and derive optimal simple rules for fiscal authorities. We find that fiscal policy can play an important role in reacting to inflation, output, and the terms of trade, but that not much is lost if national fiscal policy is restricted to react, on the one hand, to national differences in inflation and, on the other hand, to either national differences in output or changes in the terms of trade. However, welfare is reduced if national fiscal policy responds only to output, ignoring inflation.
The Eurosystem, the U.S. Federal Reserve, and the Bank of Japan: Similarities and Differences
Authors: GERDESMEIER DIETER , MONGELLI FRANCESCO PAOLO , ROFFIA BARBARA
Published: September 2007

The paper provides a systematic comparison of the Eurosystem, the U.S. Federal Reserve, and the Bank of Japan. These monetary authorities exhibit somewhat different status and tasks, which reflect different historical conditions and national characteristics. However, widespread changes in central banking practices in the direction of greater independence and increased transparency, as well as changes in the economic and financial environment over the past 15–20 years, have contributed to reduce the differences among these three world's principal monetary authorities. A comparison based on simple “over‐the‐counter” policy reaction functions shows no striking differences in terms of monetary policy implementation.
The Macroeconomic Effects of Nonzero Trend Inflation
Authors: AMANO ROBERT , AMBLER STEVE , REBEI NOOMAN
Published: September 2007

We study the macroeconomic effects of nonzero trend inflation in a simple dynamic stochastic general equilibrium model under three common time‐dependent pricing schemes: Calvo, truncated‐Calvo, and Taylor. We show that, regardless of the pricing mechanism, trend inflation leads to a reduction in the stochastic means of output, consumption and employment, and an increase in the stochastic mean of inflation beyond its deterministic steady‐state level. The variability of most aggregates also increases. These effects are quantitatively much stronger with Calvo pricing.
Certainty Equivalence and the Excess Sensitivity of Private Consumption
Authors: POZZI LORENZO , MALENGIER GRIET
Published: September 2007

For a panel of OECD countries, we show that the magnitude of the estimate for the excess sensitivity of private consumption to current income cannot be explained by a model based on certainty equivalence.
Electrical Isolation of the Superior Vena Cava: An Adjunctive Strategy to Pulmonary Vein Antrum Isolation Improving the Outcome of AF Ablation
Authors: ARRUDA MAURICIO , MLCOCHOVA HANKA , PRASAD SUBRAMANYA K. , KILICASLAN FETHI , SALIBA WALID , PATEL DIMPI , FAHMY TAMER , MORALES LUIS SAENZ , SCHWEIKERT ROBERT , MARTIN DAVID , BURKHARDT DAVID , CUMMINGS JENNIFER , BHARGAVA MANDEEP , DRESING THOMAS , WAZNI OUSSAMA , KANJ MOHAMED , NATALE ANDREA
Published: September 2007

PV isolation at the antrum (PVAI) has improved safety and efficacy of ablation procedures for atrial fibrillation (AF). AF triggers from the superior vena cava (SVC) may compromise the outcome of PVAI.

Purpose: We evaluated the (1) incidence of SVC triggers, (2) feasibility of empiric SVC electrical isolation (SVCI) as an adjunct to PVAI, and (3) SVCI safety.

Methods and Results: Of 190  patients (group I), 24 (12%) showed SVC triggers. Following PVAI, seven patients had AT originating from the SVC and three had AF. After SVCI, all 24  patients were arrhythmia‐free 450 ± 180  days post procedure. In the subsequent 217  patients (group II), empirical SVCI was performed following PVAI. Sixty‐six of all 407  patients (16%) experienced recurrence of AF.  A repeat procedure in 25 of the 66  patients showed that five (20%) had AF recurrence initiated by SVC triggers, of whom four were among group I patients (4/190; 2%) and one was from group II (1/217; 0.4%), (P < 0.05). Transient diaphragmatic paralysis can be avoided by pacing at the lateral aspect of the SVC using high output (30  mA). There was no SVC stenosis on CT scans before or 3 months after the procedure. There was no sinus node injury.

Conclusions: The SVC harbors the majority of non‐PV triggers of AF. SVCI is feasible, safe, and may be considered as an adjunctive strategy to PVAI for ablation of AF. The long‐term favorable outcome of this hybrid approach remains to be evaluated in a larger series of patients.
The Heart Rate‐Lowering Agent Ivabradine Inhibits the Pacemaker Current Ifin Human Atrial Myocytes
Authors: EL CHEMALY ANTOUN , MAGAUD CHRISTOPHE , PATRI SYLVIE , JAYLE CHRISTOPHE , GUINAMARD ROMAIN , BOIS PATRICK
Published: September 2007

Introduction:It has been speculated that pacemaker current (If) in human atria could play a role in causing ectopic atrial automaticity. Ivabradine is a novel selective and specific Ifinhibitor in the sinus node that reduces heart rate without any negative inotropic effect. The aim of the study was to explore possible effects of ivabradine on Ifin atrial myocytes.

Methods and Results: Using patch‐clamp technique, we studied effects of ivabradine on Ifpresent in atrial myocytes isolated from human right appendages of patients undergoing cardiac surgery. The identification of HCN isoforms was obtained by means of multiplex single‐cell RT‐PCR. Ivabradine induced a marked concentration and use‐dependent Ifinhibition with an IC50at steady state of 2.9 μM. Time constant of block development (Tauon) decreases with the increase in the ivabradine concentration. Use‐dependent inhibition induced by ivabradine (3 μM) was not modified in the presence of cAMP (10 μM) in the pipette solution. Multiplex single‐cell RT‐PCR indicates that the major HCN gene subtype detected in atria was HCN2. HCN4 is detected weakly and HCN1 is not significantly detected.

Conclusions: Ivabradine inhibits Ifcurrent in the nonpacemaker cell with characteristics similar to those described previously in rabbit sinus node cells, but revealed a lesser sensitivity for Ifrecorded in human atrial cell than hHCN4 subunits considered as the major contributors to nativef‐channels in human sinoatrial node. A potential protection of atrial arrhythmias by ivabradine is discussed.
Impact of Heart Rhythm Status on Registration Accuracy of the Left Atrium for Catheter Ablation of Atrial Fibrillation
Authors: DONG JUN , DALAL DARSHAN , SCHERR DANIEL , CHEEMA AAMIR , NAZARIAN SAMAN , BILCHICK KENNETH , ALMASRY IBRAHIM , CHENG ALAN , HENRIKSON CHARLES A. , SPRAGG DAVID , MARINE JOSEPH E. , BERGER RONALD D. , CALKINS HUGH
Published: September 2007

Introduction: Registration accuracy is of crucial importance to the successful use of image integration technique to facilitate atrial fibrillation (AF) ablation. It is well known that a patient's heart rhythm can switch from sinus rhythm (SR) to AF or vice versa during an AF ablation procedure. However, the impact of the heart rhythm change on the accuracy of left atrium (LA) registration has not been studied.

Methods: 
This study included 10 patients who underwent AF ablation. Prior to the ablation procedure, the patients had contrast‐enhanced cardiac CT scan obtained during SR (n = 7) or AF (n = 3). Using an image integration system (CartoMerge, Biosense Webster Inc.), LA CT surface reconstruction was registered to the real‐time mapping space represented by the LA electroanatomic map. To determine the effect of rhythm change on registration accuracy, LA registration was performed during both SR and AF in each study subject. The distance between the surface of the registered LA CT reconstruction and multiple real‐time LA electroanatomic map points (surface‐to‐point distance) was used as an index for LA registration error. The position error after rhythm change was defined as the surface‐to‐point distance between the surface of the LA CT reconstruction registered in the initial rhythm and the LA electroanatomic map points sampled during the second rhythm.

Results: A total of 90 ± 12 and 92 ± 9.5 LA electroanatomic map points were sampled for registration during SR and AF, respectively. No significant difference was found in surface‐to‐point distance when comparing SR with AF as the underlying rhythm during registration (1.91 ± 0.24 vs 1.84 ± 0.38 mm, P = 0.60). The position error after rhythm change was not different from the surface‐to‐point distance of LA registration conducted during the initial rhythm (2.05 ± 0.39 vs 1.96 ± 0.29 mm, P = 0.4). The surface‐to‐point distance did not differ when comparing LA registration conducted during the same versus different rhythm from that during CT imaging (1.96 ± 0.29 vs 1.79 ± 0.32 mm, P = 0.13).

Conclusions: Registration error did not differ between LA registrations conducted during the same versus different rhythm as was present during CT imaging. Rhythm changes between SR and AF did not introduce significant error to the LA registration process for catheter ablation of AF. These findings are reassuring and suggest that reregistration is not needed if a patient's rhythm changes from SR to AF or vice versa during an ablation procedure.
Phylogeny and Nucleomorph Karyotype Diversity of Chlorarachniophyte Algae
Authors: SILVER TIA D. , KOIKE SAYAKA , YABUKI AKINORI , KOFUJI RUMIKO , ARCHIBALD JOHN M. , ISHIDA KEN‐ICHIRO
Published: September 2007

ABSTRACT. Chlorarachniophytes are flagellated and/or reticulopod‐forming marine algae with chlorophyll a‐ and b‐containing plastids of secondary endosymbiotic origin. They are one of only two algal groups known to possess a “nucleomorph” (i.e. the remnant nucleus of the eukaryotic endosymbiont that donated the plastid). Apart from the recently sequenced nucleomorph genome of Bigelowiella natans, little is known about the size, structure, and composition of chlorarachniophyte nucleomorph genomes. Toward the goal of better understanding nucleomorph genome diversity, as well as establishing a phylogenetic framework with which to interpret variation in chlorarachniophyte morphology, ultrastructure, and life cycle, we are studying a wide range of chlorarachniophyte strains from public culture collections and natural habitats. We have obtained 22 new chlorarachniophyte nuclear and nucleomorph 18S rRNA gene (18S rDNA) sequences and nucleomorph genome size estimates for 14 different strains. Consistent with previous studies, all of the chlorarachniophytes examined appear to possess three nucleomorph chromosomes. However, our results suggest considerable variation in nucleomorph genome size and structure, with individual chromosome sizes ranging from ∼90 to ∼210 kbp, and total genome sizes between ∼330 kbp in Lotharella amoebiformis and ∼610 kbp in unidentified chlorarachniophyte strain CCMP622. The significance of these phylogenetic and nucleomorph karyotype data is discussed.
A Biochemical Comparison of Proteases from Pathogenic Naegleria fowleri and Non‐Pathogenic Naegleria gruberi
Authors: SERRANO‐LUNA JESÚS , CERVANTES‐SANDOVAL ISAAC , TSUTSUMI VICTOR , SHIBAYAMA MINEKO
Published: September 2007

ABSTRACT. Naegleria fowleri is the etiologic agent of primary amoebic meningoencephalitis (PAM). Proteases have been suggested to be involved in tissue invasion and destruction during infection. We analyzed and compared the complete protease profiles of total crude extract and conditioned medium of both pathogenic N. fowleri and non‐pathogenic Naegleria gruberi trophozoites. Using SDS‐PAGE, we found differences in the number and molecular weight of proteolytic bands between the two strains. The proteases showed optimal activity at pH 7.0 and 35 °C for both strains. Inhibition assays showed that the main proteolytic activity in both strains is due to cysteine proteases although serine proteases were also detected. Both N. fowleri and N. gruberi have a variety of different protease activities at different pH levels and temperatures. These proteases may allow the amoebae to acquire nutrients from different sources, including those from the host. Although, the role of the amoebic proteases in the pathogenesis of PAM is not clearly defined, it seems that proteases and other molecules of the parasite as well as those from the host, could be participating in the damage to the human central nervous system.
Microheterogeneity and Coevolution: An Examination of rDNA Sequence Characteristics in Neoparamoeba pemaquidensis and Its Prokinetoplastid Endosymbiont
Authors: CARAGUEL CHARLES G. B. , O'KELLY CHARLES J. , LEGENDRE PIERRE , FRASCA SALVATORE , GAST REBECCA J. , DESPRÉS BÉATRİCE M. , CAWTHORN RICHARD J. , GREENWOOD SPENCER J.
Published: September 2007

ABSTRACT. Neoparamoeba pemaquidensis, the etiological agent of amoebic gill disease, has shown surprising sequence variability among different copies of the 18S ribosomal RNA gene within an isolate. This intra‐genomic microheterogeneity was confirmed and extended to an analysis of the internal transcribed spacer (ITS) region. High levels of intra‐genomic nucleotide diversity (Pi=0.0201–0.0313) were found among sequenced ITS regions from individual host amoeba isolates. In contrast, the ITS region of its endosymbiont revealed significantly lower levels of intra‐genomic nucleotide diversity (Pi=0.0028–0.0056) compared with the host N. pemaquidensis. Phylogenetic and ParaFit coevolution analyses involving N. pemaquidensis isolates and their respective endosymbionts confirmed a significant coevolutionary relationship between the two protists. The observation of non‐shared microheterogeneity and coevolution emphasizes the complexity of the interactions between N. pemaquidensis and its obligate endosymbiont.
Spliced Leader RNA‐Mediated trans‐Splicing in a Dinoflagellate, Karenia brevis
Authors: LIDIE KRISTY B. , VAN DOLAH FRANCES M.
Published: September 2007

ABSTRACT. Spliced leader (SL) trans‐splicing is a form of mRNA processing originally described in parasitic kinetoplastids. During this reaction, a short RNA sequence is transferred from the 5′‐end of an SL transcript to a splice acceptor site on pre‐mRNA molecules. Here we report numerous mRNAs from a dinoflagellate, Karenia brevis, which contain an identical leader sequence at their 5′‐terminal end. Furthermore, we have isolated a gene from K. brevis encoding a putative SL RNA containing the conserved splice donor site immediately following the leader sequence. A 1,742‐bp DNA fragment encoding a K. brevis 5S gene repeat was found to encode the SL RNA gene, as well as a U6 small nuclear RNA (snRNA) gene, and binding sites for the core components of the splicesome (Sm proteins) involved in RNA splicing. Therefore the K. brevis SL RNA appears to be in a genomic arrangement typical of SL genes in a number of species known to mature their mRNAs by trans‐splicing. Additionally, we show that the SL gene exists as a stable snRNA and has a predicted secondary structure typical of SL RNAs. The data presented here support the hypothesis that an SL RNA is present in K. brevis and that maturation of a percentage of mRNAs in K. brevis occurs via a trans‐splicing process in which a common SL sequence is added to the 5′‐end of mature mRNAs. The occurrence of SL trans‐splicing in a dinoflagellate extends the known phylogenetic range of this process.
Small‐Subunit rRNA Phylogenies Suggest ThatEpalxella antiquorum(Penard, 1922) Corliss, 1960 (Ciliophora, Odontostomatida) Is a Member of the Plagyopylea
Authors: STOECK THORSTEN , FOISSNER WILHELM , LYNN DENIS H.
Published: September 2007

ABSTRACT.The odontostomatid ciliates have remained a homogeneous order of ciliates since the 1930s when they were recognized as a monophyletic assemblage. Since that time they have been placed with the heterotrich ciliates, and more recently transferred as incertae sedis to the new “riboclass” class Armophorea. We were able to obtain the small subunit rRNA gene sequence of the odontostomatidEpalxella antiquorum(Penard, 1922) Corliss, 1960, collected from the meromictic alpine Lake Alat in Germany, in July 2005. An alignment with representatives of all 11 classes of ciliates unambiguously places theEpalxellasequence with other representatives of the class Plagiopylea with 100% support in both maximum likelihood and Bayesian analyses.Epalxellais the basal lineage with trimyemid and plagiopylid ciliates forming the two terminal sister clades. While this molecular support is strong and unambiguous, there are no obvious morphological features to unite these three clades. Thus, the class Plagiopylea must continue to be referred to as a “riboclass.” Using theEpalxellasequence as a basal marker, we tentatively identified 20 environmental sequences to the terminal plagiopylean clades: eight to the genusTrimyema; four to the genusPlagiopyla; and eight to two new species, one of which might represent a new plagiopylean genus.
Processing of Particle‐Stabilized Wet Foams Into Porous Ceramics
Authors: Gonzenbach Urs T. , Studart André R. , Steinlin David , Tervoort Elena , Gauckler Ludwig J.
Published: September 2007

Direct foaming of colloidal suspensions is a simple and versatile approach for the fabrication of macroporous ceramic materials. Wet foams produced by this method can be stabilized by long‐chain surfactants or by colloidal particles. In this work, we investigate the processing of particle‐stabilized wet foams into crack‐free macroporous ceramics. The processing steps are discussed with particular emphasis on the consolidation and drying process of wet foams. Macroporous alumina ceramics prepared using different consolidation and drying methods are compared in terms of their final microstructure, porosity, and compressive strength. Consolidation of the wet foam by particle coagulation before drying resulted in porous alumina with a closed‐cell structure, a porosity of 86.5%, an average cell size of 35 μm, and a remarkable compressive strength of 16.3 MPa. On the other hand, wet foams consolidated via gelation of the liquid within the foam lamella led to porous structures with interconnected cells in the size range from 100 to 150 μm. The tailored microstructure and high mechanical strength of the macroporous ceramics can be of interest for the manufacture of bio‐scaffolds, thermal insulators, impact absorbers, separation membranes, and light weight ceramics.
Preparation of 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 Thin Films Via a Polyvinylpyrrolidone‐Assisted Aqueous Sol–Gel Process and Dielectric Properties
Authors: Nakagauchi Ryo , Kozuka Hiromitsu
Published: September 2007

Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN–PT) thin films were prepared by spin coating using aqueous solutions of metal salts containing polyvinylpyrrolidone, where niobium oxide layers and lead—magnesium–titanium oxide layers were laminated on Pt(111)/TiOx/SiO2/Si(100) substrates and fired at 750° or 800°C. 250 ± 20 nm thick 0.7PMN–0.3PT thin films of a single‐phase perovskite could be prepared, and the film fired at 750°C had dielectric constants and dielectric loss of 1900 ± 350 and 0.13 ± 0.03, respectively, exhibiting polarization‐electric field hysteresis with a remanent polarization of 5.1 μC/cm2 and a coercive field of 21 kV/cm.
Orientation Control Growth of Lanthanum Nickelate Thin Films Using Chemical Solution Deposition
Authors: Chen Shu‐Tao , Wang Gen‐Shui , Zhang Yuan‐Yuan , Yang Li‐Hui , Dong Xian‐Lin
Published: September 2007

Highly (100)‐ and (110)‐oriented LaNiO3 (LNO) thin films were successfully prepared on a Si (100) substrate using the chemical solution deposition method. It was somewhat surprising to find that the orientation of LNO films depended on the heating rates of the temperature range of 200°–400°C. The samples with heating rates beyond 10°C/s showed the preferential (100) orientation, while those with heating rates below 6.67°C/s showed the preferential (110) orientation. The orientation mechanism is controlled by the thermodynamics of nucleation and crystal growth. LNO films with controlled orientation having low resistivities of 2 mΩ·cm are a good basis for integrating ferroelectric applications.
Low Dielectric Loss Polytetrafluoroethylene/TeO2 Polymer Ceramic Composites
Authors: Subodh Ganesanpotti , Joseph Manoj , Mohanan Pezholil , Sebastian Mailadil Thomas
Published: September 2007

TeO2 particle‐filled PTFE composites were prepared by the powder processing technique. The structure and microstructure of the composites were investigated by X‐ray diffraction and scanning electron microscopic methods. The effect of the ceramic content (0–0.6 volume fraction) of TeO2 on the dielectric properties of the composites was studied at 1 MHz and 7 GHz. The dielectric constant and dielectric loss increased with an increase in the TeO2 content. For 60 vol% of TeO2, the composite has a dielectric constant of 5.4 and a loss tangent of 0.006 at 7 GHz. The measured dielectric constant (ɛr) is compared with the effective dielectric constant calculated using different theoretical models. The observed dielectric constants are in agreement with that calculated using effective medium theory. The coefficient of thermal expansion of the composites decreases with the TeO2 content, reaching a minimum of 32 ppm/°C for 60 vol% loading.
Ceramics With Ultra‐Low Density Fabricated by Gelcasting: An Unconventional View
Authors: Chen Ruifeng , Huang Yong , Wang Chang‐An , Qi Jianqiang
Published: September 2007

Gelcasting is conventionally used to acquire high‐density ceramic parts; however, in this work, alumina (Al2O3) ceramics with ultra‐low density (8%–40% theoretical density) were successfully fabricated by this method. In this research, polymerization of acrylamide was realized in tert‐butyl alcohol/Al2O3 slurries with solid loading ranging from 5 to 15 vol%. Green bodies with ultra‐low density could be dried with very small shrinkage, and relatively high green strengths (1–3 MPa) were achieved. By choosing different initial solid loadings and sintering temperatures, ceramic microstructures could be effectively controlled, with the porosity ranging from 60% to 92% and pore sizes from 0.1 to 2.2 μm. Sintered Al2O3 showed high open porosity (90%), high specific area (14 m2/g) and high compression strength (>10 MPa), which was attributed to the connection of Al2O3 particles. This technique is considered potentially useful in many applications, and introduces a new application field of gelcasting.
Ferroelectric Properties of Pb(Zn1/3Nb2/3)O3–PbTiO3–RNbO3(R=Na, K) Ceramics
Authors: Park Jong‐Sung , Lee Jung‐Kun , Park Hyun‐min , Hong Kug Sun
Published: September 2007

We investigate the ferroelectric properties of Pb(Zn1/3Nb2/3)O3–PbTiO3(PZN–PT)‐based ceramics, which are stabilized by adding a small amount of NaNbO3 (NN) and KNbO3 (KN). As the content of alkali niobate increased, the ferroelectric properties of Pb(Zn1/3Nb2/3)O3–PbTiO3–RNbO3 (PZN–PT–RN; R=Na, K) became softer, which was more pronounced in PZN–PT–KN. The difference in the piezoelectric properties between PZN–PT–KN and PZN–PT–NN was explained by the cation size effect. Because the ionic size of Na is smaller than that of K, the Na ion can retain the ferroelectricity of the solid solution more effectively. The field‐induced strain of 85PZN–5PT–10NN under 10 kV/cm was as high as 0.1%. Also, the addition of NN increased the tunability of dielectric constant significantly. At a composition of 85PZN–5PT–20NN, the tunability was 90% and no hysteresis was observed. In contrast to RN, the increase in the content of PT caused the transition from relaxor to normal ferroelectrics, which were accompanied by the structural change from the rhombohedral to tetragonal phase.
Structural and Electrical Properties of Er2O3‐Doped Na1/2Bi1/2TiO3Lead‐Free Piezoceramics
Authors: Wu Mengjia , Lu Yiqing , Li Yongxiang
Published: September 2007

Sodium bismuth titanates Na1/2Bi1/2TiO3(NBT) doped with 0–3 wt% Er2O3were prepared by the conventional solid‐state reaction method. The X‐ray diffraction results revealed that the sintered Er‐doped NBT ceramics exhibited a pure perovskite structure with Er3+concentrations ranging from 0 to 1 wt%. At a low Er2O3concentration, the Er‐doped NBT ceramics showed enhanced electrical properties with dielectric constant ɛ33T/ɛ0=636, a low dielectric dissipation factor (tan δ=3.3%), a low coercive field (Ec=4.56 kV/mm), and a high piezoelectric constant (d33=75 pC/N). The relationship between the composition and properties of Er‐doped NBT ceramics has been discussed.
Fabrication of Thick (>10 μm) GeO2 Ceramic Films by a Facile Liquid Phase Deposition Process
Authors: Jing Chengbin , Hou Jinxia , Zhang Yongheng
Published: September 2007

GeO2 thick (>10 μm) ceramic films were fabricated by facile liquid‐phase deposition. The solubility of hexagonal GeO2 in water was increased ten times on adding aqueous ammonia at 70°C because of the formation of soluble Ge5O112–. With the addition of sulfuric acid, the alkaline GeO2–aqueous ammonia was neutralized, leading to the transformation of Ge5O112− into GeO2 precipitates. When the H2SO4/NH4OH molar ratio was higher than 11.7, immediate precipitation of GeO2 particles took place in the solution with no GeO2 particles deposited on the substrate. When the H2SO4/NH4OH molar ratio was decreased from 5.85 to 0.29, the precipitation process was retarded, leading to the gradual growth of uniform hexagonal GeO2 thick films on the substrates. The compactness of the film increased with a decrease in the H2SO4/NH4OH molar ratio. The growth of the GeO2 crystal film followed the Bravais–Freidel–Donnay–Harker and Hartman–Perdok models, and the cubic GeO2 particles with a size of about 10 μm were finally formed on the film. No GeO2 precipitate was produced on the substrate when the GeO2–aqueous ammonia had an excessively low H2SO4/NH4OH molar ratio (≤0.15) because the GeO2 solute did not reach the saturation level and the nucleation process could not take place on the substrate. The particles on the film surface deposited from the solution with an H2SO4/NH4OH molar ratio of 0.29 exhibited a nanopore structure. An initial study using this film as a support for KNO3 catalyst was carried out and the result revealed that the catalyst showed good catalytic activity of diesel soot oxidation.
A Molecular Dynamic Study of Cementitious Calcium Silicate Hydrate (C–S–H) Gels
Authors: Dolado Jorge S. , Griebel Michael , Hamaekers Jan
Published: September 2007

In this article, we study the polymerization of silicic acids (Si(OH)4) in the presence of calcium ions by molecular dynamics simulations. We focus on the formation and structure of cementitious calcium silicate hydrate (C–S–H) gels. Our simulations confirm that, in accordance with experiments, a larger content of calcium ions slows down the polymerization of the cementitious silicate chains and prevents them from forming rings and three‐dimensional structures. Furthermore, by an analysis of the connectivity of our simulated silicate chains and by a count of the number of Ca–OH and Si–OH bonds formed, the relationship with commonly used structural models of C–S–H gels, such as 1.4 nm tobermorite and jennite, is discussed.
TEM/STEM Observation of ZrC‐Coating Layer for Advanced High‐Temperature Gas‐Cooled Reactor Fuel
Authors: Aihara Jun , Ueta Shohei , Yasuda Atsushi , Ishibashi Hideharu , Takayama Tomoo , Sawa Kazuhiro , Motohashi Yoshinobu
Published: September 2007

The Japan Atomic Energy Agency (JAEA) has started to study and develop ZrC‐coated fuel particles for advanced high‐temperature gas‐cooled reactors. The ZrC‐coating layer was fabricated using the bromide process at JAEA. In the early stage of the project, however, the deposition temperature was varied. This paper mainly focuses on the microstructures of the ZrC‐coating layer developed in the early stage of the project. Some circumferential stripes were observed in the ZrC‐coating layer on optical micrographs. It was found that the stripes were caused by the nonuniform distribution of the free carbon phase. It was also revealed by means of transmission electron microscope /scanning transmission electron microscope observations that crystal grains of the ZrC were small and columner in shape, and were not equiaxed especially near the surface. It appears that the oscillated deposition temperature results in the nonuniform distribution of the free carbon region. The structure of the free carbon region formed in the ZrC‐coating layer appeared to be such that the c‐plane was roughly parallel to its lengthened direction. The ZrC‐coating layer appeared to be bound to the PyC layer. Fibrous carbon existing at the PyC/ZrC boundary was also observed.
Infection of potato plants with potato leafroll virus changes attraction and feeding behaviour of Myzus persicae
Authors: Alvarez A. E. , Garzo E. , Verbeek M. , Vosman B. , Dicke M. , Tjallingii W. F.
Published: September 2007

Potato leafroll virus (PLRV; genus Polerovirus, family Luteoviridae) is a persistently transmitted circulative virus that depends on aphids for spreading. The primary vector of PLRV is the aphid Myzus persicae (Sulzer) (Homoptera: Aphididae). Solanum tuberosum L. potato cv. Kardal (Solanaceae) has a certain degree of resistance to M. persicae: young leaves seem to be resistant, whereas senescent leaves are susceptible. In this study, we investigated whether PLRV‐infection of potato plants affected aphid behaviour. We found that M. persicae's ability to differentiate headspace volatiles emitted from PLRV‐infected and non‐infected potato plants depends on the age of the leaf. In young apical leaves, no difference in aphid attraction was found between PLRV‐infected and non‐infected leaves. In fact, hardly any aphids were attracted. On the contrary, in mature leaves, headspace volatiles from virus infected leaves attracted the aphids. We also studied the effect of PLRV‐infection on probing and feeding behaviour (plant penetration) of M. persicae using the electrical penetration graph technique (DC system). Several differences were observed between plant penetration in PLRV‐infected and non‐infected plants, but only after infected plants showed visual symptoms of PLRV infection. The effects of PLRV‐infection in plants on the behaviour of M. persicae, the vector of the virus, and the implications of these effects on the transmission of the virus are thoroughly discussed.
Reproducibility of pixel‐by‐pixel analysis of Heidelberg retinal flowmetry images: the Thessaloniki Eye Study
Authors: Mavroudis Leonidas , Harris Alon , Topouzis Fotis , Wilson M. Roy , Yu Fei , Anastasopoulos Eleftherios , Koskosas Archimidis , Siesky Brent , Pappas Theofanis , Founti Panayiota , Coleman Anne L.
Published: September 2007

Purpose:  To identify the investigator effect in the analysis results of Heidelberg retinal flowmetry (HRF) images when pixel‐by‐pixel analysis is performed.

Methods:  Thirty‐two of 732 HRF images were randomly selected from a population‐based study. Pixel‐by‐pixel analysis was performed by two trained masked graders in the following way: a square window of 40 × 40 pixels or two windows of 30 × 30 pixels or four windows of 20 × 20 pixels free from blood vessels at the peripapillary retina were identified. Using a 1 × 1‐pixel window, the grader performed pointwise analysis according to a specific protocol. The analysis process was performed by each observer three times (A, B, C) at 1‐week intervals. The percentage of pixels with < 1 arbitrary unit of flow (zero flow), the 10th, 25th, 50th, 75th and 90th percentiles and mean flow values were calculated. The difference between the results of analyses B−A and C−A for all HRF parameters was estimated using the Wilcoxon signed rank test. Mixed‐effect regression models were also used after controlling for grader effect and correlation within subjects.

Results:  There was no statistically significant difference between the results of analyses B−A and C−A or for any parameter in the mixed‐effect regression models. Intraclass correlation was 0.9665 for the percentage of zero flow pixels.

Conclusions:  Pixel‐by‐pixel analysis of HRF images by trained graders remains a highly reproducible method. No grader effect was found. If a precise protocol is followed, the results are independent of the exact placement of the analysis windows and the pointwise analysis of the identified and mapped retinal tissue.
Comparison of gingival blood flow during healing of simplified papilla preservation and modified Widman flap surgery: a clinical trial using laser Doppler flowmetry
Authors: Retzepi M. , Tonetti M. , Donos N.
Published: September 2007

Aim: This prospective randomized‐controlled clinical trial compared the gingival blood flow responses following simplified papilla preservation (test) versus modified Widman flap (control).

Materials and Methods: Twenty contra‐lateral upper sites with pocket depth 5 mm after initial treatment in 10 chronic periodontitis patients were randomly assigned to either test or control treatment, using a split‐mouth design. Laser Doppler flowmetry recordings were performed pre‐operatively, following anaesthesia, immediately post‐operatively and on days 1, 2, 3, 4, 7, 15, 30 and 60, at nine selected sites per flap.

Results: Significant ischaemia was observed at all sites following anaesthesia and immediately post‐operatively. At the mucosal flap basis, a peak hyperaemic response was observed on day 1, which tended to resolve by day 4 at the test sites, but persisted until day 7 at the control sites. The buccal and palatal papillae blood perfusion presented the maximum increase on day 7 in both groups and returned to baseline by day 15. Both surgical modalities yielded significant pocket depth reduction, recession increase and clinical attachment gain.

Conclusions: Periodontal access flaps represent an ischaemia–reperfusion flap model. The simplified papilla preservation flap may be associated with faster recovery of the gingival blood flow post‐operatively compared with the modified Widman flap.
Controlled‐delivery chlorhexidine chip versus amoxicillin/metronidazole as adjunctive antimicrobial therapy for generalized aggressive periodontitis: a randomized controlled clinical trial
Authors: Kaner Doğan , Bernimoulin Jean‐Pierre , Hopfenmüller Werner , Kleber Bernd‐Michael , Friedmann Anton
Published: September 2007

Background: Subgingival application of chlorhexidine via a controlled‐delivery device (CHX chip) improves the clinical outcome of scaling/root planing (SRP) in therapy for chronic periodontitis. Generalized aggressive periodontitis (GAP) is commonly treated with SRP and adjunctive antimicrobial medication. To date, the efficacy of CHX chips in GAP therapy has not been evaluated.

Aim: To compare SRP plus adjunctive CHX chip placement with SRP plus adjunctive systemic amoxicillin/metronidazole with regard to clinical efficacy in first‐line therapy for GAP.

Material and Methods: Thirty‐six GAP patients were treated with SRP and randomly with either placement of CHX chips or systemic amoxicillin/metronidazole. Clinical attachment level (CAL), probing depth (PD), bleeding on probing (BoP) and suppuration (Pus) were measured at baseline, 3 and 6 months after therapy.

Results: CAL, PD, BoP and Pus were significantly reduced in both groups after 3 months. In the CHX chip group, PD significantly increased again between 3 and 6 months. Finally, amoxicillin/metronidazole patients presented significantly more CAL “gain”, PD reduction and less remaining deep sites after 6 months. Pus remained detectable in CHX chip patients only.

Conclusions: In first‐line non‐surgical therapy for GAP, SRP plus adjunctive systemic amoxicillin/metronidazole was more efficacious in clinically relevant measures of outcome than SRP plus adjunctive placement of CHX chips.