Seven-year prospective clinical study on zirconia-based single crowns and fixed dental prostheses

OBJECTIVES: Zirconia-based prostheses are used for esthetic crown and fixed restorations, but follow-ups are still limited. The authors evaluated the 7-year clinical results of 303 zirconia core restorations, performed in a general dental private practice. MATERIALS AND METHODS: Clinical events (fracture and loss of retention, gingivitis, tenderness, excess cement, and temporary pain) were recorded in 303 zirconia core restorations positioned in 88 patients. Kaplan-Meier survival probability estimates were computed for failures (needed the replacement or removal of the prosthesis) and complications (resolved without replacing the prosthesis). RESULTS: One hundred and fifty single crowns (130 tooth-supported, 20 implant-supported) and 153 multiple units up to 6 elements (49 tooth-supported, 104 implant-supported) were followed-up for 7 years in 88 patients (40 men, 48 women), aged 35-89 years (mean 57). During the follow-up period, there were no complications for 287 (95 %) of the restorations. Sixteen restorations/abutment teeth (5 %) had some complication: extraction of abutment tooth (7, 2 %); caries (2, 1 %), porcelain veneer fracture (3, 1 %), loss of retention (4, 1 %). Nine (3 %) restorations were recorded as failures. The overall 7-year survival probability estimate for failures was 0.966 (95 % confidence limits, 0.932 and 0.983), for complications was 0.976 (95 % confidence limits 0.947 and 0.989), with a cumulative survival rate of 94.7 %. CONCLUSIONS: Within the analyzed follow-up, zirconia core restorations appear a good clinical solution, with favorable functional properties. CLINICAL RELEVANCE: All ceramic restorations can be successfully used for both single-and multiple-unit prostheses, either teeth or implants supported

In-depth analysis of the Naming Game dynamics: the homogeneous mixing case

Language emergence and evolution has recently gained growing attention through multi-agent models and mathematical frameworks to study their behavior. Here we investigate further the Naming Game, a model able to account for the emergence of a shared vocabulary of form-meaning associations through social/cultural learning. Due to the simplicity of both the structure of the agents and their interaction rules, the dynamics of this model can be analyzed in great detail using numerical simulations and analytical arguments. This paper first reviews some existing results and then presents a new overall understanding.Comment: 30 pages, 19 figures (few in reduced definition). In press in IJMP

Detección y profilaxis del fitoplasma del amarilleamiento del olmo en Francia

Surveys conducted since 1998, showed that symptoms typical of Elm Yellows (EY) were quite frequent in the elm conservatories of Nogent-sur-Vernisson and Guémené- Penfao, France, and on forest trees in several locations in western Europe. Phytoplasmas were detected in symptomatic trees and plants using Polymerase Chain Reaction amplification followed by Restriction Fragment Length Polymorphism analyses of conserved regions of 16S rDNA of phytoplasmas, or of the EY group-specific non ribosomal DNA fragment FD9. Potential vectors were searched among leafhoppers and planthoppers trapped in conservatories and tested for the presence of phytoplasma in their body. Sanitation of multiplication material was experimented using soaking of dormant cuttings and branches in hot water, according to the method devised for destruction of phytoplasma in grapevine multiplication material. Phytoplasmas detected in a number of the elm clones held in the conservatories and in several forest or hedgerow elm trees, showed some diversity, according to restriction analyses of the FD9 fragment. Both American and European types were characterized. Four leaf- and planthopper species were found to carry an EY phytoplasma. Plants grown from cuttings taken from EY-infected clones and soaked in hot water (50 °C, 45 mn) never developed symptoms and tested phytoplasma negative. Most of untreated control plants were all symptomatic and positive. In the future, EY phytoplasma should be carefully checked, especially in sensitive cultivars. More studies of EY phytoplasma variability and potential vecteurs and the assessment of routine use of hot water therapy in multiplication of material should be conducted.Las observaciones realizadas desde 1998 han mostrado que los síntomas típicos del amarilleamiento del olmo (EY) son muy frecuentes en los bancos de olmo de Nogent- sur-Vernisson y Guémené-Penfao, Francia, y en árboles en campo de varias localidades de Europa occidental. La presencia de fitoplasmas se detectó, mediante el uso de la reacción en cadena de la polimerasa seguida de análisis de polimorfismo de longitud de los fragmentos de restricción en regiones conservadas de rADN de16S de fitoplasmas, o del fragmento FD9 de ADN no ribosómico, específico del fitoplasma del EY, en árboles y plantas sintomáticos. Se buscó vectores potenciales entre homópteros cicadélidos y fulgóridos capturados en los invernáculos y estudiados con el fin de detectar la presencia de fitoplasmas en su cuerpo. Como tratamiento profiláctico del material reproductivo, se experimentó sumergiendo las estaquillas y ramas durmientes en agua caliente, de acuerdo con el método desarrollado para la destrucción de fitoplasmas en material de reproducción de la vid. Según el análisis de restricción del fragmento FD9, los fitoplasmas que fueron detectados en algunos clones de olmo conservados en los bancos clonales, así como en varios olmos de campo, mostraron una cierta diversidad genética. Tanto el tipo americano como el europeo fueron caracterizados. Se encontró que cuatro de las especies de cicadélidos y fulgóridos eran portadoras del fitoplasma del EY. Las plantas que se desarrollaron a partir de estaquillas de clones infectados por el EY y que habían sido sumergidas en agua caliente (50 ºC, 45 minutos) nunca presentaron síntomas. Igualmente, las pruebas para la detección del fitoplasma fueron negativas. Por el contrario, todas las plantas control que no habían sido tratadas presentaron síntomas, y los resultados de las pruebas fueron positivos. En el futuro, la presencia del fitoplasma del EY deberías ser comprobada sistemáticamente, especialmente en cultivares sensibles. Deberían desarrollarse más estudios sobre la variabilidad del fitoplasma del EY y vectores potenciales, y sobre la evaluación del uso continuo del tratamiento con agua caliente en la multiplicación del material

The impact of cerebral vasomotor reactivity on cerebrovascular diseases and cognitive impairment

The regulation of cerebral blood flow (CBF) is a complex and tightly controlled function ensuring delivery of oxygen and nutrients and removal of metabolic wastes from brain tissue. Cerebral vasoreactivity (CVR) refers to the ability of the nervous system to regulate CBF according to metabolic demands or changes in the microenvironment. This can be assessed through a variety of nuclear medicine and imaging techniques and protocols. Several studies have investigated the association of CVR with physiological and pathological conditions, with particular reference to the relationship with cognitive impairment and cerebrovascular disorders (CVD). A better understanding of the interaction between CVR and cognitive dysfunction in chronic and particularly acute CVD could help improving treatment and rehabilitation strategies in these patients. In this paper, we reviewed current knowledge on CVR alterations in the context of acute and chronic CVD and cognitive dysfunction. Alterations in CVR and hemodynamics have been described in patients with both neurodegenerative and vascular cognitive impairment, and the severity of these alterations seems to correlate with CVR derailment. Furthermore, an increased risk of cognitive impairment progression has been associated with alterations in CVR parameters and hemodynamics. Few studies have investigated these associations in acute cerebrovascular disorders and the results are inconsistent; thus, further research on this topic is encouraged

Measurement of Dielectric Suppression of Bremsstrahlung

In 1953, Ter-Mikaelian predicted that the bremsstrahlung of low energy photons in a medium is suppressed because of interactions between the produced photon and the electrons in the medium. This suppression occurs because the emission takes place over on a long distance scale, allowing for destructive interference between different instantaneous photon emission amplitudes. We present here measurements of bremsstrahlung cross sections of 200 keV to 20 MeV photons produced by 8 and 25 GeV electrons in carbon and gold targets. Our data shows that dielectric suppression occurs at the predicted level, reducing the cross section up to 75 percent in our data.Comment: 11 pages, format is postscript file, gzip-ed, uuencode-e

Kinematic algorithm to determine the energy cost of running with changes of direction

Changes of direction (CoDs) have a high metabolic and mechanical impact in field and court team sports, but the estimation of the associated workload is still inaccurate. This study aims at validating an algorithm based on kinematic data to estimate the energy cost of running with frequent 180\ub0-CoDs. Twenty-six physically active male subjects (22.4\u202f\ub1\u202f3.2\u202fyears) participated in two sessions: (1) maximum oxygen uptake (V\u307O2,max) and maximal aerobic speed (MAS) test; (2) 5-m continuous shuttle run (two 5-min trials at 50% and 75% MAS, 6-min recovery). In (2), full-body 3D-kinematics and V\u307O2 were simultaneously recorded. Actual cost of shuttle running (Cmeas) was obtained from the aerobic, anaerobic alactic and lactic components. The proposed algorithm detects "braking phases", periods of mostly negative (eccentric) work occurring at concurrent knee flexion and ground contact, and estimates energy cost (Cest) considering negative mechanical work in braking phases, and positive elsewhere. At the speed of, respectively, 1.54\u202f\ub1\u202f0.17 and 1.90\u202f\ub1\u202f0.15\u202fm\u202fs-1 (rate of perceived exertion: 9.1\u202f\ub1\u202f1.8 and 15.8\u202f\ub1\u202f1.9), Cmeas was 8.06\u202f\ub1\u202f0.49 and 9.04\u202f\ub1\u202f0.73\u202fJ\u202fkg-1\u202fm-1. Cest was more accurate than regression models found in literature (p\u202f\u202f0.05; average error: 8.3%, root-mean-square error: 0.86\u202fJ\u202fkg-1\u202fm-1). The proposed algorithm improved existing techniques based on CoM kinematics, integrating data of ground contacts and joint angles that allowed to separate propulsive from braking phases. This work constitutes the basis to extend the model from the laboratory to the field, providing a reliable measure of training and matches workload

Automated border control systems: biometric challenges and research trends

Automated Border Control (ABC) systems automatically verify the travelers\u2019 identity using their biometric information, without the need of a manual check, by comparing the data stored in the electronic document (e.g., the e-Passport) with a live sample captured during the crossing of the border. In this paper, the hardware and software components of the biometric systems used in ABC systems are described, along with the latest challenges and research trends

Anatomical Characteristics Of Intrapetrous Carotid Artery : A 3d Segmentation Study On Head Ct-Scan

The intrapetrous portion of internal carotid artery (IPCA) is one of the most unexplored anatomical regions, and its three-dimensional reconstruction in living subjects is still missing. The present study aims at describing IPCA on 3D models extracted from head CT-scans. The intrapetrous carotid artery was manually segmented on head CT-scans of 100 healthy patients free from vascular and neurological pathologies (50 males and 50 females aged between 18 and 91 years). Angles of the posterior and anterior genu, diameter and length of the horizontal portion, and volume of the entire canal were calculated through VAM\uae software. Statistically significant differences according to sex and side were assessed through two-way ANOVA test (p<0.05). Correlation of each measurement with age was calculated as well. On average the angles of the posterior and anterior genu were 120.1\ub110.4\ub0 and 118.0\ub110.0\ub0 in males, 119.5\ub19.2\ub0 and 117.6\ub110.3\ub0 in females, respectively, without statistically significant differences according to sex or side (p>0.05). Average length and diameter of the horizontal part were respectively 25.5\ub12.9 mm and 5.8\ub10.8 mm in males, 24.0\ub12.3 mm and 5.3\ub10.8 mm in females. The volume of IPCA was 0.941\ub10.215 cm3 in males, and 0.752\ub10.159 cm3 in females. Length and diameter of horizontal portion, and volume of IPCA showed statistically significant differences according to sex (p<0.05). No correlation with age was found. This study first provided data concerning not only linear and angular measurements, but also volumes of IPCA, useful in planning surgical interventions of the cranial base