bluuebunny/crossref_metadata_2025 huggingface dataset:
A Cellular Automaton for the Catalyzed Oxidation of Carbon Monoxide: the Effect of the Temperature
Authors: F Jiménez-Morales  , M C Lemos
Published: September 2005

The reaction of CO and O over a catalytic surface is studied with a cellular automata (CA) model. We extend the CA model proposed by Mai and von Niessen [Phys. Rev. A 44 R6165 (1991).] taking into account the variation of the temperature of the catalyst with the aim of analyzing the existence of oscillations in this reaction. The rate constants for the different processes which govern the reaction are chosen in the Arrhenius form. Aperiodic and quasiperiodic regimes are observed within certain limits of the surface temperature relaxation parameter. The results from the CA model presented are in agreement with several oscillatory behaviours which the catalyzed oxidation of CO exhibits.
Analytical Fit of the Sheath Thickness for Cylindrical and Spherical Probes in Cold Electropositive Plasmas According to a Radial Model
Authors: R Morales Crespo  , J I Fernández Palop  , M A Hernández  , J Ballesteros
Published: September 2005

Analytical expressions to determine sheath thickness surrounding cylindrical or spherical Langmuir probes are obtained using a radial model for cold electropositive plasmas. As has been shown by the authors, a radial model can be used to obtain numerical results to locate the sheath edge considering three different criteria, when it is parameterized according to the radius and the potential of the probe. Expressions to fit these results are provided.
Emission Frequency Modulation by Confinement Effect: Rhodamine-B Incorporated Within a Dendritic Structure
Authors: Francisco Márquez  , María José Sabater
Published: September 2005

Dendrimers are nanometric-size macromolecules with a regular tree-dimensional like array of branch units. Within this macromolecular structure it is possible to encapsulate a variety of guest molecules. In this paper we show that the photophysical properties of Rhodamine-B encapsulated into the dendritic box can be easily modulated by the innovative quantum confinement effect. The emission frequencies of this organic dye incorporated within the dendritic structure can effectively be red shifted with respect to their emission in solution and contrary to other confined spaces of considerable hardness, the magnitude of this shifting can be regulated under appropriate experimental conditions. This effect could have unprecedented applications in the development of supramolecular devices relating to the frequency tuning of organic laser dyes.
Axial Elongation of Water Droplet by Application of Electric Field for Bio-chemical Reaction System
Authors: T Hino  , E Hyashishita  , Y Yamauchi  , Y Hirohata  , M Nishikawa
Published: September 2005

In bio-micro devices, numerous functions of liquid flow such as elongation, expansion and transportation are required. Electro-wetting is one of the methods to control the liquid flow. In the present study, a water droplet was elongated in a channel based upon electro-wetting, and the effect of electrode diameter and shape of electrode immersed in a water droplet on the elongation was examined. The elongation increased as a diameter of electrode, and significantly increased when the electrode with a T-shape was employed. The electric field at the edge of water droplet is kept relatively large when the rod electrode with a large diameter or the T-shape electrode is employed. The present result can be explained by this effect, the change of local electric energy at the edge of the droplet.
Theoretical Study of the Thermodynamics of a Solvated Peptide: Contryphan Vn
Authors: M D'Alessandro  , M D'Abramo  , M Paci  , A Amadei
Published: September 2005

In recent papers we combined molecular dynamics (MD) simulations with the quasi Gaussian entropy (QGE) theory, in order to model the statistical mechanics and thermodynamics of simple solute molecules in water. In this paper we apply this approach to a more complex solute in water: a 9 residues peptide, Contryphan Vn. Results show that this approach can provide an accurate theoretical description of this complex solute-solvent system over a wide range of temperature.
A Novel Redox State Heme a Marker in Cytochrome c Oxidase Revealed by Raman Spectroscopy
Authors: C Piccoli  , G Perna  , R Scrima  , O Cela  , R Rinaldi  , D Boffoli  , V Capozzi  , N Capitanio
Published: September 2005

This study was aimed to characterize by Raman spectroscopy (excitation line 633 nm) different redox states of the mitochondrial cytochrome c oxidase. The results obtained from a systematic analysis carried out on the mitochondrial enzyme prepared under redox conditions, differently affecting the valence state of the metal prosthetic groups, and a comparison with homologous bacterial heme-copper oxidases, cytochrome c and pyridine hemo-chrome extract revealed a novel redox state marker specifically linked to the redox transition of heme a, peaking at 1645 cm-1, and tentatively assigned to the C=C and/or C=N streching mode of the imidazole ring of a proxymal histidine ligand. The possible involvment of this redox-linked conformational change in the catalytic activity of cytochrome oxidase is discussed.
Effects of Static Magnetic Fields on Primary Cortical Neurons
Authors: A Prina Mello  , E Farrell  , P J Prendergast  , V Campbell  , J M D Coey
Published: September 2005

The aim of this interdisciplinary study was to investigate the effects of a range of static magnetic fields (up to 5 T) on intracellular signalling cascades in primary rat cultured cortical neurons. Magnetic field exposures were conducted using a superconducting magnet with primary rat cultured cortical neurons maintained at 37°C. A series of test were carried out to investigate the effect of magnetic field strength on the activation of the proteins kinases, extracellular-signal regulated kinase (ERK) and c-Jun N terminal kinase (JNK). Cells were exposed to the magnetic fields for one hour, fixed in 4% paraformaldehyde and examined for ERK and JNK activation using antibodies which recognise the phosphorylated (i.e., active) form of ERK or JNK.

This immunocytochemical data demonstrate a differential activation of ERK and JNK when cells are exposed to increasing magnetic field. Thus, ERK activation was increased when cells were exposed to 0.75 T whereas JNK activation was increased at a higher magnetic field strength of 5 T.

Since ERK and JNK have been implicated in cellular differentiation and stress response, respectively, the results presented here suggest that static magnetic field strength may influence those cellular parameters.
In Vivo Study of Biological Effects of Photodynamic Therapy on Cervical Cancer
Authors: V A Marquez-Lemus  , B M Noguez-Juarez  , L Solano-Rodriguez  , A J Perez-Zapata  , O P Schneider-Ehrenberg  , F Graue-wiechers  , E Ramón-Gallegos
Published: September 2005

In 1999, Ramon et al examined the effects of δ-aminolevulinic acid (δ-ALA) on two cervical cancer cell lines (HeLa and CaLo) and normal cervical cells. The results reported additionally support the proposal that Photodynamic Therapy (PDT) could be an effective tool for treatment of cervical cancer (CeCa) by protoporphyrin IX (PpIX) accumulation. This cancer is in México considered a problem of public health.

In this project PDT was applied in a CeCa mouse model by implantation of HeLa cells in nu/nu mice, exposing it to δ-ALA to a dose that induces the greater concentration of PpIX by intratumoral and oral route, as well as the power and the number of optimal irradiations at 630 nm with a diode laser; verifying which of the used doses does not produce significant damage to the organs by means of histopatologic techniques: liver, spleen, brain and kidney, the determination of reactive substances to tiobarbituric acid (TBAR'S) and measured the amount of residual δ-ALA, the size of the tumor at the beginning and at the end of the application of the PDT.

Results. The cervical cancer mouse model is developed by implantation of 1,5 million HeLa cells, appearing at 15 days. The dose of δ-ALA that induces the greater concentration of PpIX in the tumor by intratumoral route was 40 mg of δ-ALA/kg body weight and for oral route it was 20 mg of δ-ALA/kg body weight, both routes did not present significant damage in the organs and according to the Analysis of Bifactorial Variance for the doses of δ-ALA and the organs no difference exists (p > 0.05).

The power of the used laser was 150 J/cm2 and 250 J/cm2, both applied by intratumoral and oral route after the δ-ALA administration. The greater diminution in the size of the tumor (53%) was by the δ-ALA oral route administration to a power of 150 J/cm2 with 5 irradiations in intervals of 48 h.
Redox Equilibria of Cytochrome C3 Immobilised on Self-Assembled Monolayers Coated Silver Electrodes
Authors: R E Di Paolo  , L Rivas  , D Murgida  , P Hildebrandt
Published: September 2005

Cytochromes c3 are soluble electron transfer proteins in the periplasm of sulphate-reducing bacteria. They act as electron-proton couplers between hydrogenase and the electron transfer chain of sulphate respiration. In this work, cytochrome c3 (Cyt-c3) obtained from both Desulfovibrio vulgaris and Desulfovibrio gigas, is electrostatically adsorbed on Ag electrodes coated with self-assembled monolayers of 11-mercaptoundecanoic acid. The redox equilibria of the adsorbed tetraheme protein are studied by surface enhanced resonance Raman spectroscopy (SERRS).

The quantitative analysis of the SERR spectra, which were measured as a function of the electrode potential, allows determining the redox potentials for the individual hemes of Cyt-c3. The values obtained of the redox potentials are compared with the data provided by NMR experiments and by molecular dynamics simulation studies of the electrostatically bound protein on a coated electrode. It is found that immobilisation causes substantial shifts of the redox potential, which would have an impact on the intramolecular electron flow.
Ab initio Reconstructions of the Shape of Cellobiose Dehydrogenase and its Domains in Solution
Authors: P Zipper  , H Durchschlag
Published: September 2005

Three-dimensional low-resolution models of the biochemically and biotechno- logically significant enzyme cellobiose dehydrogenase (CDH) were predicted by advanced modeling approaches based on experimental one-dimensional low-resolution small-angle x-ray scattering (SAXS) data. In particular, the ab initio modeling program DAMMIN by Svergun was used to predict the shape of both the whole protein and the two major constituent units (heme and FAD domains). The validity of the approach applied was tested in a systematic way by a critical assessment of scattering profiles (scattering intensities, pair-distance distribution functions) and structural and hydrodynamic parameters (hydrated particle volume, radius of gyration, maximum particle diameter, sedimentation and diffusion coefficients) and a comparison to available experimental data. Obviously, the applied approach enables the prediction of the solution structure of both CDH and its domains with a high degree of probability, though the problem of shape uniqueness remains crucial, similar to the use of other solution methods. The obtained results demonstrate the possibility to unravel particle shapes by ab initio calculations, without knowledge of high-resolution data, and confirm earlier trial-and-error models.
Quartz Luminescence Applied in Palaeoenvironmental Reconstruction of a Dune
Authors: K R Przegiętka  , D Richter  , A Chruścińska  , H L Oczkowski  , K R Lankauf  , J Szmańda  , M Luc  , W Chudziak
Published: September 2005

Optically stimulated luminescence (OSL) and thermoluminescence (TL) dating were applied for studying the evolution of a dune at the archaeological site of Kałdus (Lower Vistula Valley, Poland), where excavation revealed a settlement sequence. The dating results are supported by investigations of optical bleaching characteristics of the dune quartz. The luminescence studies presented here are a part of a wider interdisciplinary project studying the dynamics of the local geomorphology and its relationship to human activity at the site from prehistoric times until early medieval ages.
Dynamics of Tripartite Entanglement
Authors: S Shelly Sharma  , N K Sharma
Published: September 2005

Maximally entangled states are of utmost importance to quantum communication, dense coding, and quantum teleportation. With a trapped ion placed inside a high finesse optical cavity, interacting with field of an external laser and quantized cavity field, a scheme to generate a maximally entangled three qubit GHZ state, is proposed. The dynamics of tripartite entanglement is investigated, using negativity as an entanglement measure and linear entropy as a measure of mixedness of a state. It is found that (a) the number of modes available to the subsystem determines the maximum entanglement of a subsystem, (b) at entanglement maxima and minima, linear entropy and negativity uniquely determine the nature of state, but the two measures do not induce the same ordering of states, and (c) for a special choice of system parameters maximally entangled tripartite two mode GHZ state is generated. The scheme presented for GHZ state generation is a single step process and is reduction-free.
Evaluation of Stripping in Bituminous Mixtures Using Conventional and Image Processing Techniques
Authors: Obaidat MT , Abo-Qudais S , Obaidat AF
Published: September 2005

The objective of this research was to investigate the stripping problem in bituminous mixtures using both conventional and image processing techniques (IPT). Partial factorial combinations of asphalt mixture slabs were fabricated. A Marshall mold was modified to produce slabs of 300 mm × 300 mm × 60 mm. The mixtures were prepared using different combinations: two types of aggregates (limestone and valley gravel), two asphalt penetration grades (80/100 and 60/70), three types of additives (lime, cement, and a mixture of lime and cement), and one aggregate gradation (average of ASTM boundaries). The slabs were exposed to one of four environmental conditioning techniques: wet-dry (W-D), freezing-thawing (F-T), water immersion (I), and surface bonding (S-B). Eighty-one slabs were prepared, 19 were tested without conditioning (control slabs), and the rest were exposed to different weathering conditioning. Four cores were prepared from each slab, two for the indirect tensile strength test and the others for the Marshall stability test.

A normal-based camera was used to map the surfaces of the control and conditioned slabs as well as cross-sections generated from cores tested under the indirect tensile strength test. The Silicon Video Image Processing (SVIP) software was used to digitize images for the surfaces of slabs and cores. Images were analyzed to prepare statistical parameters, intensity diagrams, and histograms for intensities based on two approaches: area-based analysis and line-based analysis.

Results of the analysis indicated that 1) conventional and image processing techniques proved that surface bonding increased stability and tensile strength for conditioned slabs more than for unconditioned slabs; 2) IPT predicted stripping in limestone mixtures with AC 80/100 using the retained intensity concept and this result agreed with that of retained Marshall stability (RMS); however, it did not consistently predict the stripping potential of mixtures consisting of valley gravel due to the tone intensity effect of aggregate; 3) lime additive demonstrated the best indirect tensile strength and Marshall stability; however, the additive mix consisting of lime and cement exhibited reduction in water damage for mixtures with AC 60/70; 4) slab mixtures resisted weather conditioning more than conventional cylindrical Marshall specimens; and 5) an area-based analysis scheme using peaks, not averages of intensities, was more reliable in predicting stripping than the line-based analysis, and it was more reliable for core cross-sections than slab surfaces.
Previous Stress Facilitates Fear Memory, Attenuates GABAergic Inhibition, and Increases Synaptic Plasticity in the Rat Basolateral Amygdala
Authors: Manzanares Pablo A. Rodríguez , Isoardi Nora A. , Carrer Hugo F. , Molina Víctor A.
Published: September 2005

In experiments designed to investigate the relationship between stress and the acquisition of new fear memories, it was found that previous exposure to a restraint session increased fear conditioning in a contextual fear paradigm. Moreover, the infusion of bicuculline, a competitive antagonist of GABAAreceptors, into the basolateral amygdala complex (BLA), but not into the central amygdaloid nucleus, induced the same behavioral effect. Pretreatment with midazolam (MDZ), a positive modulator of GABAAsites, prevented the facilitating influence on fear memory of both stress and GABAAreceptor blockade in the BLA. These data suggest that facilitation of fear conditioning could be causally related to increased neuronal excitability attributable to depressed GABAergic inhibition in the BLA. To test this hypothesis, evoked potentials were studied in brain slices from stressed animals. Potentials evoked in the BLA by single stimuli applied to the external capsule showed multispike responses, suggestive of GABAergic disinhibition. These multiple responses were no longer evident after the slices were perfused with diazepam or if the stressed animals were pretreated with MDZ. In slices from stressed rats, paired-pulse inhibition (GABA dependent) was suppressed. Also, in stressed animals, long-term potentiation (LTP) was induced with a single train of high-frequency stimulation, which did not induce LTP in control rats. Moreover, MDZ pretreatment prevented the facilitating influence of stress on LTP induction. All of these findings support the hypothesis that previous stress attenuates inhibitory GABAergic control in the BLA, leading to neuronal hyperexcitability and increased plasticity that facilitates fear learning.
The Role of Ventral Frontostriatal Circuitry in Reward-Based Learning in Humans
Authors: Galvan Adriana , Hare Todd A. , Davidson Matthew , Spicer Julie , Glover Gary , Casey B. J.
Published: September 2005

This study examined changes in behavior and neural activity with reward learning. Using an event-related functional magnetic resonance imaging paradigm, we show that the nucleus accumbens, thalamus, and orbital frontal cortex are each sensitive to reward magnitude, with the accumbens showing the greatest discrimination between reward values. Mean reaction times were significantly faster to cues predicting the greatest reward and slower to cues predicting the smallest reward. This behavioral change over the course of the experiment was paralleled by a shift in peak in accumbens activity from anticipation of the reward (immediately after the response), to the cue predicting the reward. The orbitofrontal and thalamic regions peaked in anticipation of the reward throughout the experiment. Our findings suggest discrete functions of regions within basal ganglia thalamocortical circuitry in adjusting behavior to maximize reward.
Solubility product of plutonium hydrous oxide and its ionic strength dependence
Authors: Fujiwara K. , Yamana Hajimu , Fujii T. , Moriyama Hirotake
Published: September 2005

The solubility of PuO2·xH2O was measured at 25°C in a NaClO4solution containing Na2S2O4as a reductant. The experiment was carried out by an oversaturation method atI= 1.0 and by an undersaturation method atI= 0.5, 1.0 and 2.0. The concentration of Pu3+was measured by α-spectrometry and UV/Visible spectrophotometry, and the equilibrium constant of the reaction, PuO2·xH2O + e−= Pu3++ 4 OH−+ (x–2) H2O, was obtained. From the obtained results, the solubility product (Ksp) of PuO2·xH2O, for PuO2·xH2O = Pu4++ 4 OH−+ (x − 2) H2O atI= 0.5, 1.0 and 2.0 was determined. By using the specific interaction theory (SIT), the solubility product of PuO2·xH2O at the standard state (I= 0) was determined to be logK°sp= −57.97 ± 0.24, and the ion interaction coefficient ε(Pu4+, ClO4-) was also evaluated to be 0.99 ± 0.20.
Molecular Characterization of the Major Wheat Domestication Gene Q
Authors: Simons Kristin J , Fellers John P , Trick Harold N , Zhang Zengcui , Tai Yin-Shan , Gill Bikram S , Faris Justin D
Published: September 2005

The Q gene is largely responsible for the widespread cultivation of wheat because it confers the free-threshing character. It also pleiotropically influences many other domestication-related traits such as glume shape and tenacity, rachis fragility, spike length, plant height, and spike emergence time. We isolated the Q gene and verified its identity by analysis of knockout mutants and transformation. The Q gene has a high degree of similarity to members of the AP2 family of transcription factors. The Q allele is more abundantly transcribed than q, and the two alleles differ for a single amino acid. An isoleucine at position 329 in the Q protein leads to an abundance of homodimer formation in yeast cells, whereas a valine in the q protein appears to limit homodimer formation. Ectopic expression analysis allowed us to observe both silencing and overexpression effects of Q. Rachis fragility, glume shape, and glume tenacity mimicked the q phenotype in transgenic plants exhibiting post-transcriptional silencing of the transgene and the endogenous Q gene. Variation in spike compactness and plant height were associated with the level of transgene transcription due to the dosage effects of Q. The q allele is the more primitive, and the mutation that gave rise to Q occurred only once leading to the world's cultivated wheats.
The Paternal Gene of the DDK Syndrome Maps to the Schlafen Gene Cluster on Mouse Chromosome 11
Authors: Bell Timothy A , de la Casa-Esperón Elena , Doherty Heather E , Ideraabdullah Folami , Kim Kuikwon , Wang Yunfei , Lange Leslie A , Wilhemsen Kirk , Lange Ethan M , Sapienza Carmen , de Villena Fernando Pardo-Manuel
Published: September 2005

The DDK syndrome is an early embryonic lethal phenotype observed in crosses between females of the DDK inbred mouse strain and many non-DDK males. Lethality results from an incompatibility between a maternal DDK factor and a non-DDK paternal gene, both of which have been mapped to the Ovum mutant (Om) locus on mouse chromosome 11. Here we define a 465-kb candidate interval for the paternal gene by recombinant progeny testing. To further refine the candidate interval we determined whether males from 17 classical and wild-derived inbred strains are interfertile with DDK females. We conclude that the incompatible paternal allele arose in the Mus musculus domesticus lineage and that incompatible strains should share a common haplotype spanning the paternal gene. We tested for association between paternal allele compatibility/incompatibility and 167 genetic variants located in the candidate interval. Two diallelic SNPs, located in the Schlafen gene cluster, are completely predictive of the polar-lethal phenotype. These SNPs also predict the compatible or incompatible status of males of five additional strains.
Post-transcriptional Silencing and Functional Characterization of theDrosophila melanogasterHomolog of HumanSurf1
Authors: Zordan Mauro A , Cisotto Paola , Benna Clara , Agostino Alessandro , Rizzo Giorgia , Piccin Alberto , Pegoraro Mirko , Sandrelli Federica , Perini Giuliana , Tognon Giuseppe , De Caro Raffaele , Peron Samantha , Kronniè Truus te , Megighian Aram , Reggiani Carlo , Zeviani Massimo , Costa Rodolfo
Published: September 2005

Mutations in Surf1, a human gene involved in the assembly of cytochrome c oxidase (COX), cause Leigh syndrome, the most common infantile mitochondrial encephalopathy, characterized by a specific COX deficiency. We report the generation and characterization of functional knockdown (KD) lines for Surf1 in Drosophila. KD was produced by post-transcriptional silencing employing a transgene encoding a dsRNA fragment of the Drosophila homolog of human Surf1, activated by the UAS transcriptional activator. Two alternative drivers, Actin5C–GAL4 or elav–GAL4, were used to induce silencing ubiquitously or in the CNS, respectively. Actin5C–GAL4 KD produced 100% egg-to-adult lethality. Most individuals died as larvae, which were sluggish and small. The few larvae reaching the pupal stage died as early imagos. Electron microscopy of larval muscles showed severely altered mitochondria. elav–GAL4-driven KD individuals developed to adulthood, although cephalic sections revealed low COX-specific activity. Behavioral and electrophysiological abnormalities were detected, including reduced photoresponsiveness in KD larvae using either driver, reduced locomotor speed in Actin5C–GAL4 KD larvae, and impaired optomotor response as well as abnormal electroretinograms in elav–GAL4 KD flies. These results indicate important functions for SURF1 specifically related to COX activity and suggest a crucial role of mitochondrial energy pathways in organogenesis and CNS development and function.
Evidence of P-Element-Induced Sister-Chromatid Exchange in a Ring-X Chromosome in Drosophila, With Implication for a High Rate of Formation of Hybrid Elements
Authors: Sved John A , Liang Xiumei
Published: September 2005

Activation of a single incomplete P element induces recombination at a rate of ∼0.5–1% in the male germline of Drosophila. Male recombination rises by an order of magnitude to ∼20% if homologous P elements are involved. The high rate of recombination suggests the possibility that sister-chromatid exchange (SCE) might be elevated to a similar extent, since homologous P elements must always be present in sister chromatids. This possibility was tested by recombining a single P element onto a ring-X chromosome and using sex-ratio distortion to measure the loss of the ring-X due to SCE in the male germline. The results confirmed a rate of loss comparable to that expected with homologous elements, although the rate of loss was variable. Both SCE and recombination results are consistent with the “hybrid element insertion” model, in which the left and right ends from different elements associate, providing that insertion occurs preferentially in the vicinity of a P-element end. For autosomes, hybrid element formation may thus occur at a much higher rate than the 0.5–1% implied by single element recombination, with only a small minority of hybrid element excision events being resolved by recombination.
Perinatal Loss of Ts65Dn Down Syndrome Mice
Authors: Roper Randall J , St. John Heidi K , Philip Jessica , Lawler Ann , Reeves Roger H
Published: September 2005

Ts65Dn mice inherit a marker chromosome, T(1716)65Dn, producing segmental trisomy for orthologs of about half of the genes on human chromosome 21. These mice display a number of phenotypes that are directly comparable to those in humans with trisomy 21 and are the most widely used animal model of Down syndrome (DS). However, the husbandry of Ts65Dn mice is complicated. Males are sterile, and only 20–40% of the offspring of Ts65Dn mothers are trisomic at weaning. The lower-than-expected frequency of trisomic offspring has been attributed to losses at meiosis, during gestation and at postnatal stages, but no systematic studies support any of these suppositions. We show that the T(1716)65Dn marker chromosome is inherited at expected frequency and is fully compatible with development to midgestation. Disproportional loss of trisomic offspring occurs in late gestation and continues through birth to weaning. Different maternal H2 haplotypes are significantly associated with the frequency of trisomy at weaning in patterns different from those reported previously. The proportion of trisomic mice per litter decreases with age of the Ts65Dn mother. These results provide the first statistical and numerical evidence supporting the prenatal and perinatal pattern of loss in the Ts65Dn mouse model of DS.
A Long‐Term Study of Implants Supporting Overdentures as a Model for Implant Success
Authors: Schwartz‐Arad Devorah , Kidron Nomi , Dolev Eran
Published: September 2005

Background: Implant‐supported overdentures have been a common treatment for edentulous patients for the past 20 years, achieving good clinical results. The purpose of this study was to examine survival and success rates of implants supporting overdentures in the maxilla and mandible and to examine the influence of factors related to patients, implant procedure, implant data, and follow‐up period on implant success.

Methods: During a 10‐year period (1990 to 2000), 285 implants were placed in 62 patients to support 69 overdentures (seven patients had overdentures in both jaws). Patients ranged in age from 45 to 85 years (mean 64.5 years). The files of 61 patients, including 277 implants supporting 68 overdentures (14 maxillary and 54 mandibular), had measurable radiographic post‐exposure follow‐up (range 6.63 to 110.93 months, mean 37.93 months) for cervical bone loss (CBL) measurements. Bone loss was measured by radiographic examination in which the mean number of exposed threads in mesial and distal sides of the implant was considered. Implants were rehabilitated by overdentures with bar (N = 52) or ball (N = 16) attachments.

Results: Implant survival rate was 96.1% (11/285 did not survive) and total 10‐year cumulative survival rate was 95.4% (maxilla, 83.5%, mandible, 99.5%). The success rate was 70.4% (maxilla, 41.9%; mandible, 80.8%) when using Albrektsson et al. success criteria. A logistic regression analysis showed that the maxilla (P <0.0001) and a short follow‐up period (up to 5 years) (P = 0.017) were the most influencing factors enhancing CBL.

Conclusions: 1) Survival of implants supporting overdentures was very high; 2) implants supporting overdentures in the maxilla had greater CBL than in the mandible; and 3) new criteria of implant success should be considered. J Periodontol 2005;76: 1431‐1435.
Posterior Mandibular Alveolar Distraction Osteogenesis Utilizing an Extraosseous Distractor: A Prospective Study
Authors: Polo Wilson C.K. , Cury Patricia R. , Sendyk Wilson R. , Gromatzky Alfredo
Published: September 2005

Background: The aim of this clinical study was to evaluate bone elongation and the effectiveness of distraction osteogenesis when utilizing an extraosseous distractor to treat cases of atrophic posterior mandible.

Methods: Fourteen surgical sites were evaluated in 10 healthy, non‐smoking, female patients, with varying degrees of atrophic posterior mandible, who underwent surgery by alveolar bone distraction. The patients presented between 6 and 10 mm above the mandibular, inferior alveolar nerve. Panoramic radiographs were taken before surgery and at the beginning and end of the consolidation period. The extraosseous distractor was fixed to both the basal and the osteotomized bone. After a 7‐day latency period, the patients rotated the distractor rod three times a day for 3 to 10 days (1 mm per day). The mobile segment was held in place for 8 to 12 weeks for bone consolidation.

Results: The results revealed a distraction range of 2.32 to 8.11 mm (mean distraction ± standard deviation, 5.12 ± 1.67 mm), which was less than the real, measured distance between the upper and lower miniplates of the distractor (5.58 ± 1.62 mm). The bone segments showed between 0.03 and 2.53 mm (mean, 0.88 ± 0.59 mm) resorption above the upper miniplate. The effi‐ cacy of the extraosseous distractor was calculated as between 30.41% and 94.58% (73.45% ± 20.32%).

Conclusions: Bone regeneration was obtained in all cases; however, when planning alveolar bone distraction using the extraosseous distractor, greater distraction should be performed to compensate for the inclination of the distractor rod and possible bone loss. This adjustment should increase the efficacy of distraction osteogenesis. J Periodontol 2005;76:1463‐1468.
Influence of Additional Active Ingredients on the Effectiveness of Non‐Alcoholic Chlorhexidine Mouthwashes: A Randomized Controlled Trial
Authors: Bascones Antonio , Morante Sergio , Mateos Leopoldo , Mata Montserrat , Poblet Jorge
Published: September 2005

Background: Non‐alcoholic chlorhexidine mouthwashes are equally effective and have fewer potential risks than hydroalcoholic solutions. Nowadays, other active ingredients are added to these mouthwashes in an attempt to improve their effectiveness and reduce side effects. Following an experimental gingivitis model, this study examined three non‐alcoholic commercial mouthwashes having 0.12% chlorhexidine digluconate (CHX) in common.

Methods: Using a double masked, cross‐over design, 30 subjects underwent three consecutive experimental phases with three mouthwashes: CHX, CHX + 0.05% sodium fluoride (CHXNaF), and CHX + 0.05% cetylpyridinium chloride (CHX‐CPC). In each one of these 21‐day phases, the subjects discontinued all oral hygiene measures and were treated exclusively with the experimental mouthwash randomly assigned (an oral rinse twice a day). Each experimental phase was preceded by a 14‐day washout period. Levels of gingivitis, dental plaque, supragingival calculus, and dental staining were assessed at baseline and end (day 21) of experimental phases.

Results: The evolution of gingival and dental staining indices did not show statistically significant differences between the treatments. Differences were noticed in the plaque index (P = 0.0002), with CHX‐NaF the treatment with the greatest increase. Differences were also observed in the supragingival calculus index (P = 0.0136), with CHX‐CPC showing a smaller increase. Tongue staining was more frequent with CHX‐CPC (P = 0.0141).

Conclusion: In non‐alcoholic 0.12% chlorhexidine mouthwashes, the addition of other active ingredients does not produce beneficial effects, but may even reduce the antiplaque effectiveness or increase tongue staining. J Periodontol 2005;76:1469‐1475.
Bone Filling Around Titanium Implants May Benefit From Smoking Cessation: A Histologic Study in Rats
Authors: César‐Neto João B. , Benatti Bruno B. , Sallum Enilson A. , Sallum Antonio W. , Nociti Francisco H.
Published: September 2005

Background: Although a harmful effect of smoking on titanium implants has been documented, only a few studies have investigated the benefits of smoking cessation. Thus, this study histologically investigated whether smoking cessation influences bone healing around titanium implants and comparatively evaluated temporary versus complete cessation protocols.

Methods: Sixty‐six male Wistar rats were randomly assigned to one of four groups: control (N = 16); CSI, intermittent cigarette smoke inhalation (CSI) throughout the entire 150‐day experiment (N = 17); P‐CSI, CSI 83 days prior to implant placement (N = 17); or R‐CSI, CSI for 83 days, cessation 7 days before and 21 weeks after implant placement, and return to CSI for 39 days (N = 16). The animals were sacrificed and the degree of boneto‐ implant contact (BIC) and the bone area (BA) within the limits of the implant threads obtained for cortical (zone A) and cancellous bone (zone B).

Results: Intergroup analysis (Kruskal‐Wallis test, α = 0.05) demonstrated a significant effect of CSI on BA (P <0.05) and that temporary or complete CSI cessation protocols resulted in values similar to those of the control group (P >0.05) 88.91% ± 4.29%; 80.66% ± 6.55%; 84.27% ± 6.96%; 85.71% ± 4.7% in zone A, and 51.28% ± 6.49%; 38.69% ± 10.78%; 48.87% ± 8.47%; 49.47% ± 8.04%; in zone B for groups CTRL, CSI, P‐CSI, and R‐CSI, respectively.

Conclusion: Within the limits of the present investigation, temporary and complete CSI cessation reversed the effect of smoke exposure on bone healing around titanium implants in both cortical and cancellous bone. J Periodontol 2005;76:1476‐1481.
Amelogenin Stimulates Bone Sialoprotein (BSP) Expression Through Fibroblast Growth Factor 2 Response Element and Transforming Growth Factor‐β1 Activation Element in the Promoter of the BSP Gene
Authors: Shimizu Emi , Saito Ryoichiro , Nakayama Youhei , Nakajima Yu , Kato Naoko , Takai Hideki , Kim Dong‐Soon , Arai Masato , Simmer James , Ogata Yorimasa
Published: September 2005

Background: Amelogenins are a complex mixture of hydrophobic proteins that are the major organic component of developing enamel. The principal function of the amelogenins and their degradation products has been assigned to structural roles in creating the space and milieu for promoting enamel mineralization. Enamel matrix derivative (EMD) has been used clinically for periodontal regeneration and its therapeutic effectiveness has been attributed to amelogenin, non‐amelogenin enamel matrix proteins, and growth factors. While EMD is believed to induce periodontal regeneration, the precise mechanism is not known. Bone sialoprotein (BSP), an early phenotypic marker of osteoblast and cementoblast differentiation, has been implicated in the nucleation of hydroxyapatite during bone formation. In this study, we examined the ability of amelogenin to regulate BSP gene transcription in osteoblast like cells.

Methods: We conducted Northern hybridization, transient transfection analyses, and gel mobility shift assays using full‐length recombinant amelogenin to determine the molecular basis of the transcriptional regulation of BSP gene by amelogenin.

Results: Recombinant amelogenin (1 µg/ml, 12 hours) increased BSP mRNA levels ∼2.4‐fold. In transient transfection analyses, amelogenin (1 µg/ml, 12 hours) increased luciferase activity ∼1.5‐fold in pLUC3 (nucleotides –116 to +60) and further increased pLUC5 (nucleotides –801 to +60) activity ∼2.3‐fold transfected into ROS 17/2.8 cells. Amelogenin also increased luciferase activities in rat stromal bone marrow cells. The effect of amelogenin was inhibited by the tyrosine kinase inhibitor herbimycin A. Transcriptional stimulation by amelogenin was almost completely abrogated in cells expressing a BSP promoter construct with a mutation in the fibroblast growth factor 2 (FGF2) response element (FRE). Gel mobility shift assays with radiolabeled FRE and transforming growth factor‐β1 (TGF‐β1) activation element (TAE) ds‐oligonucleotides revealed increased binding of nuclear proteins from amelogenin‐stimulated ROS 17/2.8 cells.

Conclusion: Amelogenin stimulation alters BSP gene transcription by inducing nuclear proteins that bind to the FRE and TAE in the rat BSP gene promoter. J Periodontol 2005;76:1482‐1489.
Age‐Related and Surgically Induced Estrogen Deficiencies May Differently Affect Bone Around Titanium Implants in Rats
Authors: Duarte Poliana Mendes , Gonçalves Patrícia Furtado , Zaffalon Casati Márcio , Sallum Enilson Antonio , Nociti Francisco H.
Published: September 2005

Background: Valuable information has been obtained using the ovariectomy model; however, clinical studies have indicated that such a model may not be appropriate to parallel with the postmenopausal condition and titanium implants. Thus, this study aimed to comparatively evaluate, by histometric analysis, the influence of age‐related (ARED) and surgically induced (OVX) estrogen deficiencies on bone around titanium implants inserted in rats.

Methods: Single screw‐shaped titanium implants were placed in rat tibiae and animals were then assigned to one of the following groups: SHAM (N = 15): bilateral sham ovariectomies in 90‐day‐old rats, 21 days before implant placement; OVX (N = 15): bilateral ovariectomies in 90‐day‐old rats, 21 days before implant placement; and ARED (N = 15): implant placement in reproductive aged rats (22 months old). After 60 days, the animals were sacrificed and undecalcified sections obtained. Boneto‐ implant contact (BIC) and bone area (BA) within the limits of implant threads and bone density (BD) in a 500 µm‐wide zone lateral to the implant were obtained and arranged for cortical (zone A) and cancellous (zone B) bone regions.

Results: For zone A, intergroup analysis showed no signifi‐ cant differences regarding BIC and BA (P >0.05). In contrast, ARED negatively influenced BD around the implants (P <0.05). In zone B, OVX negatively affected BIC and BA (P <0.05), and both ARED and OVX groups demonstrated lower BD than the SHAM group (P <0.05).

Conclusion: Within the limits of this study, it can be concluded that ARED mainly affects preexisting bone while OVX more significantly affects both newly formed and preexisting bone. J Periodontol 2005;76:1496‐1501.
Using a Delphi Panel to Survey Criteria for Successful Periodontal Therapy in Posterior Teeth
Authors: Lightfoot W. Scott , Hefti Arthur , Mariotti Angelo
Published: September 2005

Background: Health care providers have focused on outcome measures to determine the success or failure of treatment. In periodontics, there is no consistent view regarding what outcome measure( s) is(are) important for successful treatment. This study used a Delphi surveying technique to determine which outcome measures were clinically relevant to an expert panel of periodontists.

Methods: The Delphi surveyed 35 periodontists from the United States to determine the level of importance of attachment level, probing depth, furcation involvement, mobility, plaque, inflammation, esthetics, pain, and patient satisfaction following periodontal treatment of posterior teeth in a patient with severe chronic periodontitis. The Delphi panelists were questioned concerning the relative importance of each outcome measure, a minimally acceptable level considered necessary for success for each outcome measure, and the length of time required for these outcome measures to remain stable.

Results: Following two rounds of Delphi surveys, the panelists considered the control of pain to be an “extremely important” outcome measure for successful periodontal treatment. Attachment levels, probing depths, plaque levels, degree of inflammation, function, furcation involvement, and patient satisfaction were considered to be “very important” outcomes for successful periodontal treatment. The minimally acceptable reduction in probing depths following 1 year of treatment was 2 mm; whereas up to 1 mm of attachment loss was considered acceptable. The panel found that Glickman grade 2 furcation involvement or Miller degree II mobility would be considered an acceptable outcome for clinical success. Finally, the panel agreed that the 1‐year results of treatment should remain stable for a minimum of 5 years.

Conclusions: The Delphi surveying technique proved useful in developing a hierarchy for the relevance of periodontal outcome measures. Absence of pain was the only outcome measure considered to be “extremely important” for successful therapy. Although panelists considered attachment loss, furcation invasions, and mobility as “very important” outcomes, they were willing to accept loss of attachment of up to 1 mm, grade 2 furcation involvement, and degree II mobility following treatment as long as outcomes remained stable for 5 years. These data suggest that minimal standards for success of posterior teeth can be established among periodontal practitioners. J Periodontol 2005;76:1502‐1507.
Using a Delphi Panel to Survey Criteria for Successful Periodontal Therapy in Anterior Teeth
Authors: Lightfoot W. Scott , Hefti Arthur , Mariotti Angelo
Published: September 2005

Background: Valuable decision making for periodontal treatment success in situations where there is ambiguous or conflicting information was previously reported using a consensus building method, the Delphi survey, for posterior teeth with chronic periodontitis. This study focuses on outcome measures relevant in assessing therapy of anterior teeth with chronic periodontitis.

Methods: The Delphi panelists were the same American periodontists who participated in the previous Delphi survey evaluating successful therapy in posterior teeth. In this study, panelists determined the level of importance of attachment level, probing depth, mobility, plaque, inflammation, esthetics, pain, and patient satisfaction following periodontal treatment of a single tooth or multiple anterior teeth in a patient with severe chronic periodontitis. The panelists were questioned concerning the relative importance of each outcome measure, a minimally acceptable level considered necessary for success for each outcome measure, and the length of time required for these outcome measures to remain stable.

Results: The 35 panelists considered the control of pain, esthetics, and patient satisfaction to be “extremely important” outcome measures for successful periodontal treatment of single or multiple teeth. Attachment levels, probing depths, plaque levels, degree of inflammation, and mobility (for multiple teeth) were considered to be “very important” outcomes. The minimally acceptable reduction in probing depths following 1 year of treatment was 2 mm; whereas 2 mm of attachment gain was considered necessary for successful treatment. The panel also found a Miller degree I mobility as an acceptable outcome for clinical success. Finally, the panel agreed that the 1‐year results of treatment should remain stable for a minimum of 5 years.

Conclusions: The Delphi technique proved a practical instrument to transform expert opinion into a group consensus for relevant periodontal outcome measures. Absence of pain, esthetics, and patient satisfaction were outcome measures considered “extremely important” for successful therapy. Although panelists considered attachment loss, probing depths, and mobility somewhat less important outcomes, they wanted an attachment gain of 2 mm and would accept a degree I mobility as long as outcomes remained stable for 5 years. These data suggest that minimal standards for successful therapy of anterior teeth can be established among periodontal practitioners. J Periodontol 2005;76:1508‐1512.
The Basal Phosphorylation Sites of Endothelial Nitric Oxide Synthase at Serine (Ser)1177, Ser116, and Threonine (Thr)495 in Rat Molar Epithelial Rests of Malassez
Authors: Korkmaz Yüksel , Bloch Wilhelm , Addicks Klaus , Schneider Kurt , Baumann Michael A. , Raab Wolfgang H.‐M.
Published: September 2005

Background: The epithelial rests of Malassez (ERM) are derived from the Hertwig's epithelial root sheath during tooth development. The ERM contain endothelial nitric oxide synthase (eNOS), but the existence of phosphorylation site/s of eNOS in the ERM is unclear.

Methods: Rat molars with periodontium were perfusion‐ and post‐fixed, decalcified, and frozen‐sectioned. Free‐floating sections were incubated using antisera against total eNOS, eNOS phosphorylated at serine (Ser)1177, Ser116, and threonine (Thr)495. The signal intensities of t‐eNOS, p‐eNOS at Ser1177 and Ser116 in the ERM were measured by densitometry and statistically analyzed.

Results: In the ERM, localization of total eNOS and the phosphorylation sites of eNOS at Ser1177 and Ser116 were detected, while a basal localization of eNOS phosphorylated at Thr495 in the ERM was undetectable. For p‐eNOS at Ser116 regional differences in phosphorylation were detected.

Conclusions: The basal production of NO by eNOS in the ERM is modulated by phosphorylation of eNOS at Ser1177 and Ser116 residues, while the basal activity of the eNOS is not influenced by phosphorylation of eNOS at Thr495 residue. This provides evidence that phosphorylation plays a key role for regulation of the catalytic activity of eNOS. J Periodontol 2005;76:1513‐1519.