9,054 research outputs found

    A review on the prevention of inflammatory periimplant diseases

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    Background: An impressive number of dental implants are inserted worldwide. Evolution in dental implants and simplification of surgical techniques allowed a significant increase in the number of dentists involved in implant surgery. Most of them are general dentists, are not always sufficiently formed and experienced, frequently use low-quality implants, do not adopt the proper patient selective criteria, do not adequately monitor and maintain the inserted implants, and do not report their own statistics to the dental community. Consequently, the incidence of inflammatory periimplant diseases (IPDs) has progressively increased to values significantly higher than those previously indicated by the scientific literature. Materials and Methods: Two main literature searches were undertaken in October 2018 in the PubMed Website database. Only articles written in English and published from 2008 onward were considered; 'Clinical Trial,' 'Meta analysis,' 'Observational study,' 'Review,' and 'Validation study' were selected as article type filters. The following keywords were used in the searches: 'Peri implantitis prevention' and 'Dental implant failure prevention.'Results: Preventive measures are analyzed according to the different factors that can favor the occurrence of an infection. The factors are divided into (i) implant dependent, (ii) patient dependent, and (iii) surgeon dependent. Conclusions: Scientific and clinical data confirm that when materials are selected with care, patients are carefully evaluated for factors of risk and attitude to adhere to the necessary maintenance program, and operative protocols and maintenance programs are respected dental implants can be attractive and effective tools for oral rehabilitation. Nevertheless, dentists and patients should have greater awareness that in many cases the decision to utilize dental implants cannot be taken lightly

    Towards the Modeling of Neuronal Firing by Gaussian Processes

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    This paper focuses on the outline of some computational methods for the approximate solution of the integral equations for the neuronal firing probability density and an algorithm for the generation of sample-paths in order to construct histograms estimating the firing densities. Our results originate from the study of non-Markov stationary Gaussian neuronal models with the aim to determine the neuron's firing probability density function. A parallel algorithm has been implemented in order to simulate large numbers of sample paths of Gaussian processes characterized by damped oscillatory covariances in the presence of time dependent boundaries. The analysis based on the simulation procedure provides an alternative research tool when closed-form results or analytic evaluation of the neuronal firing densities are not available.Comment: 10 pages, 3 figures, to be published in Scientiae Mathematicae Japonica

    Ku & C Band solid state switch matrix for satellite payloads using LTCC multilayer substrate

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    This paper describes the design and development of Ku and C band solid state switch matrix for multimedia satellite payloads. The design, through the use of advanced packaging techniques, allows significant savings on mass and volume with respect to traditional electromechanical switches while guaranteeing a comparable reliability

    In vivo evaluation of operative torque generated by two Nickel-Titanium rotary instruments during root canal preparation

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    Objectives This in vivo study evaluated the operative torque and preparation time of ProTaper NEXT (Dentsply Maillefer; Ballaigues, Switzerland) and EdgeFile X7 (EdgeEndo; Albuquerque, New Mexico, United States) rotary systems during root canal preparation of maxillary premolars. Materials and Methods Ten double-rooted maxillary premolars with independent canals were selected. Each canal in each tooth was prepared with one of the rotary systems (n = 10), ProTaper NEXT or EdgeFile X7. The instruments were rotated at 300 rpm with maximum torque set at 2 N.cm using an electric motor (KaVo; Biberach, Germany) that automatically recorded torque values at every 1/10th of a second (ds). Statistical Analysis Operative torque (N.cm) and preparation time (s) of the first shaping instrument (size 17/.04) of both rotary systems were recorded and statistically compared using the Mann-Whiney U test with a significance level set at 5%. Results No instrument exhibited flute deformation or underwent intracanal failure. No differences were found between the instruments regarding the maximum (peak) torque values (p > 0.05). EdgeFile X7 17/.04 required significantly less preparation time (3.75 seconds interquartile range [IQR]: 3.2-9.0) than ProTaper NEXT X1 (15.45 seconds IQR: 8.35-21.1) (p < 0.05). The median operative torque values of ProTaper NEXT X1 (0.26 N.cm; IQR: 0.18-0.49) were significantly higher compared with EdgeFile X7 17/.04 (0.09 N.cm; IQR: 0.05-0.17) (p < 0.05). Conclusions Although no difference was found between the median peak torque values of ProTaper NEXT X1 and EdgeFile X7 17/.04 instruments, the operative torque and instrumentation time results were impacted by their different designs and alloys during clinical preparation of root canals

    Nazwy komitetów wyborczych – aspekty strukturalne i aksjologiczne

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    The subject of this paper will be a semantic and structural analysis of the names of electoral committees, and a reference to the axiological systems that are indirectly reflected by them. The names of electoral committees are obligatory elements of electoral activities, as well as being an interesting element of political marketing

    Fatigue resistance of new and used nickel-titanium rotary instruments: a comparative study

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    Aim of the present study was twofold. First, to evaluate in vitro, the performance of two different NiTi rotary instruments in one molar case; then, to evaluate their resistance to cyclic fatigue, compared to new ones

    Thermal Conductivity Enhancement of Al2O3 Nanofluid in Ethylene Glycol and Water Mixture

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    AbstractThe ability of nanofluids that exhibits enhanced thermal performance is acknowledged by researchers through studies since decades ago. However, the observation of thermal properties for nanofluids in water and ethylene glycol based is not fully explored yet. Hence, this paper presents the thermal conductivity of water and ethylene glycol (EG) based Al2O3 nanofluid. The 13 nm sized Al2O3 nanoparticles were dispersed into three different volume ratio of water: EG such as 40:60, 50:50 and 60:40 using a two-step method. The measurement of thermal conductivity was performed using KD2 Pro Thermal Properties Analyzer at working temperatures of 30 to 70 ̊C for volume concentration of 0.5 to 2.0%. The results indicate that the thermal conductivity increases with the increase of nanofluid concentration and temperature. While the percentage of ethylene glycol increase, the range of thermal conductivity decreases due to ethylene glycol properties. The measurement data of the nanofluids give maximum enhancement of thermal conductivity at condition 2.0% volume concentration, temperature of 70 ̊C and for all base fluid

    Investigating feedforward neural regulation of circulation from analysis of spontaneous arterial pressure and heart rate fluctuations in conscious rats.

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    Investigating feedforward neural regulation of circulation from analysis of spontaneous arterial pressure and heart rate fluctuations in conscious rats. Am J Physiol Heart Circ Physiol 296: H202–H210, 2009. First published November 14, 2008; doi:10.1152/ajpheart.00358.2008.—It has been suggested in anesthetized animals that the occurrence of sequences of consecutive beats characterized by systolic arterial pressure (SAP) and RR or pulse interval (PI) changing in the opposite direction (SAP /RR and SAP /RR , nonbaroreflex sequences) might represent the expression of neural cardiovascular regulatory mechanisms operating with feedforward characteristics. The aim of the present study was to study nonbaroreflex sequences in a more physiological experimental model, i.e., in conscious freely moving rats. We studied conscious rats before and after 1) complete autonomic blockade (n 12), 2) sympathetic blockade (n 10), 3) (n 7)- and (n 8)-adrenergic blockade, and 4) parasympathetic blockade (n 10). Nonbaroreflex sequences were defined as three or more beats in which SAP and PI of the following beat changed in the opposite direction. Complete autonomic blockade reduced the number of nonbaroreflex sequences (95.6 9.0 vs. 45.2 4.1, P 0.001), as did sympathetic blockade (80.9 12.6 vs. 30.9 6.1, P 0.001). The selective -receptor blockade did not induce significant changes (80.9 12.5 in baseline vs. 79.0 14.7 after prazosin), whereas -receptor blockade significantly reduced nonbaroreflex sequence occurrence (80.9 12.5 in baseline vs. 48.9 15.3 after propranolol). Parasympathetic blockade produced a significant increase of nonbaroreflex sequences (95.1 6.9 vs. 136.0 12.4, P 0.01). These results demonstrate the physiological role of the nonbaroreflex sequences as an expression of a feedforward type of short-term cardiovascular regulation able to interact dynamically with the feedback mechanisms of baroreflex origin in the neural control of the sinus node

    Axial eccentric SynRel and SPM Motors analytical models validation using 3D finite element

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    This paper deals with the uniform and non-uniform axial eccentricity analyses of the surface mounted permanent magnet and synchronous reluctance machines. The analyses are carried out using an analytical model for each considered machine. Being the axial eccentricity a 3D physical phenomenon, the standard sliding approach used in the analytical models has been validated through accurate 3D FE simulations. The results presented in this paper verify the effectiveness of the analytical approaches quantifying the results deviations respect to the computational expensive 3D FE simulations. The results also confirms that synchronous reluctance machines show higher radial forces compared to the surface permanent magnet machines for the same eccentricity level, main geometry and operating condition
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