1,661 research outputs found

    Association between obesity and periodontal disease. A systematic review of epidemiological studies and controlled clinical trials

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    Obesity is a very prevalent chronic disease worldwide and has been suggested to increase susceptibility of periodontitis. The aim of this paper was to provide a systematic review of the association between obesity and periodontal disease, and to determine the possible mechanisms underlying in this relationship. A literature search was carried out in the databases PubMed-Medline and Embase. Controlled clinical trials and observational studies identifying periodontal and body composition parameters were selected. Each article was subjected to data extraction and quality assessment. A total of 284 articles were identified, of which 64 were preselected and 28 were finally included in the review. All the studies described an association between obesity and periodontal disease, except two articles that reported no such association. Obesity is characterized by a chronic subclinical inflammation that could exacerbate other chronic inflammatory disorders like as periodontitis. The association between obesity and periodontitis was consistent with a compelling pattern of increased risk of periodontitis in overweight or obese individuals. Although the underlying pathophysiological mechanism remains unclear, it has been pointed out that the development of insulin resistance as a consequence of a chronic inflammatory state and oxidative stress could be implicated in the association between obesity and periodontitis. Further prospective longitudinal studies are needed to define the magnitude of this association and to elucidate the causal biological mechanisms

    Mesoporous materials for clean energy technologies

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    Alternative energy technologies are greatly hindered by significant limitations in materials science. From low activity to poor stability, and from mineral scarcity to high cost, the current materials are not able to cope with the significant challenges of clean energy technologies. However, recent advances in the preparation of nanomaterials, porous solids, and nanostructured solids are providing hope in the race for a better, cleaner energy production. The present contribution critically reviews the development and role of mesoporosity in a wide range of technologies, as this provides for critical improvements in accessibility, the dispersion of the active phase and a higher surface area. Relevant examples of the development of mesoporosity by a wide range of techniques are provided, including the preparation of hierarchical structures with pore systems in different scale ranges. Mesoporosity plays a significant role in catalysis, especially in the most challenging processes where bulky molecules, like those obtained from biomass or highly unreactive species, such as CO2 should be transformed into most valuable products. Furthermore, mesoporous materials also play a significant role as electrodes in fuel and solar cells and in thermoelectric devices, technologies which are benefiting from improved accessibility and a better dispersion of materials with controlled porosity.The authors wish to thank the Spanish MINECO (Project CTQ2011-28954-C02-01) for financial support. E.S. acknowledges financial support from UA (Project GRE12-39)

    Influence of anxiety and anesthetic vasoconstrictors upon hemodynamic parameters during dental procedures in controlled hypertensive and non-hypertensive patients

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    To determine the influence of dental anxiety and the vasoconstrictor used in local anesthesia upon different hemodynamic parameters - systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR) and peripheral oxygen saturation (SatO2) - during den

    Effect of Porosity and Surface Chemistry on CO2 and CH4 Adsorption in S-Doped and S-/O-co-Doped Porous Carbons

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    The aim of this study was to determine the adsorption performance of a petroleum pitch-based activated carbon (PPAC1:3) before and after a post-treatment with H2S. In the first step, a microporous activated carbon (PPAC1:3) with a highly developed porous structure was produced through a chemical activation route with KOH. Afterward, the synthesized activated carbon was thermally treated yielding two different series of functionalized activated carbons: (i) a series of carbons were treated directly with H2S at elevated temperatures (600 °C and 800 °C), and (ii) a series of carbons were generated by combining an oxidation treatment with plasma followed by H2S treatment at elevated temperatures (600 °C and 800 °C). The chemical and structural characteristics of the S-doped and S-/O-co-doped porous carbons were investigated by means of different experimental techniques, such as XRD, RAMAN, FESEM, XPS, TPD, N2, and CO2 adsorption, and finally tested in CO2 and CH4 adsorption at atmospheric and high pressure. The functionalized porous carbons possessed specific surface areas of 2420–2690 m2/g, total pore volume of 1.05–1.18 cm3/g, and sulfur content up to 2.55 atom % (the sulfur content of the original carbon was 0.19%). After a careful analysis of the carbon dioxide and methane uptake at atmospheric (0.1 MPa) and high pressure (4 MPa), adsorption results confirm that the microporous structure is the main structural parameter defining the adsorption performance and, to a lower extent, the surface chemistry. Overall, a significant improvement in the total uptake can be appreciated after the H2S treatment.This research was funded by MCIN, and NATO. The authors would like to acknowledge financial support from the Ministerio de Ciencia e Innovación—MCIN (projects PID2019-108453GB-C21, MCIN/AEI/10.13039/501100011033 and EU “NextGeneration/PRTR” (project PCI2020-111968/3D-Photocat)), and NATO SPS program (project G5683)

    COVID-19, A new challenge in the dental practice

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    This review was conducted in order to learn the latest information about how to prevent cross-infection of COVID-19 in dentistry. The aim of this study is offer a clinical protocol to reduce the risk of infection of COVID-19 in dental settings. We carr

    Periodontal, salivary and IL-6 status in rheumatoid arthritis patients. A cross-sectional study

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    Background: The aim of this study was to determine whether saliva interleukin-6 (IL-6) levels are elevated in patients with rheumatoid arthritis versus a control group and examine the possible relationship between the oral condition and the risk of RA. Material and Methods: In 30 patients with RA and 30 healthy controls, different periodontal indices were recorded; sialometric measurements were taken to determine resting whole saliva, stimulated whole saliva and stimulated parotid saliva flow; and the saliva IL-6 levels were measured. Logistic regression analysis was performed, with the presence or absence of RA as dependent variable. Results: The patients with RA had a greater presence of bacterial plaque, a greater periodontal pocket depth, a larger percentage of medium-sized pockets, and greater periodontal attachment loss compared with the controls. Likewise, a decrease in resting and stimulated saliva flow was observed, together with an increase in saliva IL-6 levels. Logistic regression analysis reported that the plaque index is the principal differentiating factor of patients with RA. Stimulated parotid saliva flow was also significantly correlated to the presence of RA. Conclusions: The patients with RA showed a greater tendency to develop periodontal disease than the controls, with lower salivary flow and higher levels of IL-6 in saliva. Key words:Rheumatoid arthritis, periodontal disease, saliva, IL-6

    Prior oral conditions in patients undergoing heart valve surgery

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    Patients scheduled for heart valve surgery should be free of any oral infectious disorders that might pose a risk in the postoperative period. Few studies have been made on the dental conditions of such patients prior to surgery. The present study describes the most frequent prior oral diseases in this population group. A prospective, observational case-control study was designed involving 60 patients (30 with heart valve disease and 30 controls, with a mean age of 71 years in both groups). A dental exploration was carried out, with calculation of the DMFT (decayed, missing and filled teeth) index and recording of the periodontal parameters (plaque index, gingival bleeding index, periodontal pocket depth, and attachment loss). The oral mucosa was also examined, and panoramic X-rays were used to identify possible intrabony lesions. Significant differences in bacterial plaque index were observed between the two groups (p<0.05), with higher scores in the patients with valve disease. Probing depth and the presence of moderate pockets were also greater in the patients with valve disease than among the controls (p<0.01). Sixty percent of the patients with valve disease presented periodontitis. Patients scheduled for heart valve surgery should be examined for possible active periodontitis before the operation. Those individuals found to have periodontal disease should receive adequate periodontal treatment before heart surgery

    Non-porous reference carbon for N2 (77.4 K) and Ar (87.3 K) adsorption

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    A new non-porous carbon material from granular olive stones has been prepared to be used as a reference material for the characterization of the pore structure of activated carbons. The high precision adsorption isotherms of nitrogen at 77.4 K and argon at 87.3 K on the newly developed sample have been measured, providing the standard data for a more accurate comparative analysis to characterize disordered porous carbons using comparative methods such as t- and αS-methods.Financial support from a Strategic Japanese–Spanish Cooperative Program: Nanotechnologies and New Materials for Environmental Challenges (PLE2009-0052). K.K. was supported by Exotic Nanocarbons, Japan Regional Innovation Strategy Program by the Excellent, JST

    Weak matrix majorization

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    Given X, Y ∈ Rn×m we introduce the following notion of matrix majorization, called weak matrix majorization, X≻ w Y if there exists a row-stochastic matrix A ∈ Rn×n such that AX = Y, and consider the relations between this concept, strong majorization (≻s) and directional majorization (≻). It is verified that ≻ s ⇒ ≻w, but none of the reciprocal implications is true. Nevertheless, we study the implications ≻ w ⇒ ≻s and ≻ ⇒ ≻s under additional hypotheses. We give characterizations of strong, directional and weak matrix majorization in terms of convexity. We also introduce definitions for majorization between Abelian families of selfadjoint matrices, called joint majorizations. They are induced by the previously mentioned matrix majorizations. We obtain descriptions of these relations using convexity arguments.Fil: Martinez Peria, Francisco Dardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Massey, Pedro Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Silvestre, Luis Enrique. University of Texas at Austin; Estados Unido

    Evolución de la competitividad y rentabilidad del cultivo del tomate rojo (lycopersicon esculentum l.) en Sinaloa, México

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    El tomate rojo mexicano es una de las hortalizas que generan más divisas para el país, ya que cerca de 30% de la producción nacional se exporta, principalmente a los Estados Unidos de Norteamérica (EE.UU.), por lo que su cultivo depende significativamente del comportamiento del mercado internacional. En este estudio se planeó el siguiente objetivo: analizar la rentabilidad, la competitividad y la ventaja comparativa del cultivo del tomate rojo en Sinaloa en el ciclo agrícola 1999/2000, para lo cual se utilizó la metodología de la Matriz de Análisis de Política (MAP) desarrollada por Monke y Pearson (1989)
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