176 research outputs found
Entanglement entropy of an accelerating universe
We have considered the existence of a dependence of the entanglement entropy on the cosmological horizon surface area also in several accelerating models of the current universe both for a quintessence scalar field and for a phantom-energy scenario. It is shown that if a quintessence vacuum cosmic field is considered then, though the case for w>-1 satisfies a second law for entanglement entropy, when w<-1 such a law is violated. It is finally noted that the entanglement entropy and the distinct formulations of cosmic holography share common future surfaces which are optimal screen for the latter descriptions. © 2012 American Physical Society.This work was supported by MICINN under Research Project FIS2008- 06332.Peer Reviewe
Esterification of Free Fatty Acids with Glycerol within the Biodiesel Production Framework
Companies in the field of the collection and treatment of waste cooking oils (WCO) for subsequent biodiesel production usually have to cope with high acidity oils, which cannot be directly transformed into fatty acid methyl esters due to soap production. Since glycerine is the main byproduct of biodiesel production, these high acidity oils could be esterified with the glycerine surplus to transform the free fatty acids (FFA) into triglycerides before performing the transesterification. In this work, commercial glycerol was esterified with commercial fatty acids and commercial fatty acid/lampante olive oil mixtures over tin (II) chloride. In the first set of experiments, the esterification of linoleic acid with glycerol excess from 20 to 80% molar over the stoichiometric was performed. From 20% glycerol excess, there was no improvement in FFA reduction. Using 20% glycerol excess, the performance of a biochar obtained from heavy metal-contaminated plant roots was compared to that of SnCl2. Then, the effect of the initial FFA content was assessed using different oleic acid/lampante olive oil mixtures. The results illustrated that glycerolysis was impeded at initial FFA contents lower than 10%. Finally, the glycerolysis of a WCO with 9.94% FFA was assayed, without success
Surface-Active Fluorinated Quantum Dots for Enhanced Cellular Uptake
Fluorescent nanoparticles, such as quantum dots, hold great potential for biomedical applications,
mainly sensing and bioimaging. However, the inefficient cell uptake of some nanoparticles hampers their application in clinical practice. Here, the effect of the modification of the quantum dot surface with fluorinated ligands to increase their surface activity and, thus, enhance their cellular uptake was explored
Entanglement entropy of an accelerating universe
We have considered the existence of a dependence of the entanglement entropy on the cosmological horizon surface area also in several accelerating models of the current universe both for a quintessence scalar field and for a phantom-energy scenario. It is shown that if a quintessence vacuum cosmic field is considered then, though the case for w > À1 satisfies a second law for entanglement entropy, when w < À1 such a law is violated. It is finally noted that the entanglement entropy and the distinct formulations of cosmic holography share common future surfaces which are optimal screen for the latter descriptions. [7]). Actually, entanglement entropy measures a degree of the correlation between subsystems of a given quantum system All the above results allow us to confidently extrapolate the above horizon area-entanglement entropy proportionality law to any system where quantum entanglement takes place in a cosmic space-time. The results that we are going to get later on are all consistent with that extrapolation. In fact, in this brief report we are going to extend the existence of such a dependence of entanglement entropy on the cosmological horizon surface area also in accelerating models for the current universe both for a quintessence scalar dark-energy field and for a phantom-energy scenario. It will be shown that if an usual quintessence vacuum cosmic field is considered [11], then, though the case for w > À1 (note that along this report we shall only consider an equation of state for the Universe with the perfect-fluid form p ¼ w, with p the pressure and the energy density) satisfies a second law for entanglement entropy, when w < À1 such a law would be violated. We want to estimate the entanglement entropy that corresponded to a quantum field in an accelerating spacetime which is inexorable endowed with a future event horizon where w ¼ p= is the parameter of the equation of state, a 0 and t 0 are the initial values of the scale factor and time, and the constant C is given by C ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 8G=3 p , with an integration constant. We introduce then a conformal time defined by so tha
Fluorinated CdSe/ZnS quantum dots: Interactions with cell membrane
Fluorescent inorganic quantum dots are highly promising for biomedical applications as sensing and imaging agents. However, the low internalization of the quantum dots, as well as for most of the nanoparticles, by living cells is a critical issue which should be solved for success in translational research. In order to increase the internalization rate of inorganic CdSe/ZnS quantum dots, they were functionalized with a fluorinated organic ligand. The fluorinated quantum dots displayed an enhanced surface activity, leading to a significant cell uptake as demonstrated by in vitro experiments with HeLa cells. We combined the experimental and computational results of Langmuir monolayers of the DPPC phospholipid as a model cell membrane with in vitro experiments for analyzing the mechanism of internalization of the fluorinated CdSe/ZnS quantum dots. Surface pressure-molecular area isotherms suggested that the physical state of the DPPC molecules was greatly affected by the quantum dots. UV–vis reflection spectroscopy and Brewster Angle Microscopy as in situ experimental techniques further confirmed the significant surface concentration of quantum dots. The disruption of the ordering of the
DPPC molecules was assessed. Computer simulations offered detailed insights in the interaction between the quantum dots and the phospholipid, pointing to a significant modification of the physical state of the hydrophobic region of the phospholipid molecules. This phenomenon appeared as the most relevant step in the internalization mechanism of the fluorinated quantum dots by cells. Thus, this work sheds light on the role of fluorine on the surface of inorganic nanoparticles for enhancing their cellular uptake
Management of a crown-root fracture : a novel technique with interdisciplinary approach
Anterior teeth with subgingival fractures require a complex treatment plan that addresses biologic, functional and aesthetic factors. This case report describes the management of a crown-root fractured maxillary left central incisor. An interdisciplinary approach was used to restore the tooth due to the complex nature of the treatment. Orthodontic extrusion was performed to move the fracture line above the alveolar bone and periodontal surgery to recontour the altered gingival margin. Finally, the incisor was restored performing a root canal retreatment with a fiber post and a full ceramic crown. The treatment resulted in secured periodontal health and good aesthetic
Non-surgical treatment of periodontal disease in a pregnant caucasian women population: adverse pregnancy outcomes of a randomized clinical trial
Aim: To analyze if non-surgical treatment of periodontitis in a pregnant Caucasian women population can reduce adverse pregnancy outcomes. Methods and results: A parallel randomized clinical trial was designed and approved by the Ethical Committee of Sanitary Area Santiago-Lugo, Spain (registration number: 2016/451). Forty patients with periodontitis stage II grade B were randomly allocated to receive either comprehensive non-surgical periodontal therapy (test group; n = 20) or professional tooth cleaning (control group; n = 20) before 24 gestational weeks. Randomization was computer-generated by the statistic program Epidat v.4.1 and allocation was performed using sealed opaque envelopes. Clinical measurements and peripheral blood samples for biochemical variables were collected at baseline, in the middle of second trimester before non-surgical treatment, and in the third trimester. Microbiological samples were collected in the second and third trimester. A statistically significant reduction was verified in all clinical and microbiological parameters after periodontal treatment in the test group. No significant differences were observed for the rest of the variables, including preterm birth and/or low birth weight. No adverse events related to periodontal treatment were reported. Conclusions: Non-surgical periodontal treatment in Caucasian patients with periodontitis stage II grade B did not significantly reduce the risk of adverse pregnancy outcomes.S
Primary Sjögren's syndrome as independent risk factor for subclinical atherosclerosis.
To assess the prevalence of subclinical atherosclerosis in patients with primary Sjögren's syndrome (pSS) and its possible association with clinical and analytical parameters of the disease.
In this cross-sectional study, 38 consecutive patients with pSS were compared with 38 age and sex healthy controls. Demographic variables and classic cardiovascular risk factors (CVRFs): Hypertension, dyslipidemia, diabetes mellitus, obesity, and smoking habit were assessed in both groups, and also disease-related features were collected in pSS group. The presence of subclinical atherosclerosis was assessed by carotid ultrasound, with carotid intima-media thickness (CIMT) measurement and determination of the presence of atheromatous plaques.
Subclinical atherosclerosis presence was remarkably greater in patients with pSS than in healthy controls (OR = 4.17, 95%CI [1.27-16.54]), as well as CIMT values (0.79 ± 0.43mm vs. 0.66 ± 0.27mm; P = .02). No differences for classic CVRFs were found between both groups. An association of subclinical atherosclerosis with erythrocyte sedimentation rate (ESR) and rheumatoid factor (RF) was observed in patients with pSS.
This cohort showed a greater prevalence of subclinical atherosclerosis in patients with pSS, indicating this disease as an independent risk factor for presence of early vascular damage.The authors declared that this study has
received no financial support.S
Análisis de procesos que impactan en la productividad de una obra aplicando Lean Construction. Caso de estudio: Proyecto Multifamiliar Buganvillas Tercera Etapa – Comas para la etapa de estructuras y arquitectura
Objetivo: Analizar que los métodos de una gestión de producción basados en Lean Construction utilizados en la etapa de estructuras y arquitectura en la Construcción del edificio multifamiliar Buganvillas Etapa III producen un impacto en la productividad de la obra. Métodos: Se utilizarán los métodos del Lean Construcción, uso de cartas balance para la medición de productividad y análisis comparativo de ratios en las etapas anteriores del proyecto para la etapa de estructuras y arquitectura. Resultados: Se logra analizar la productividad de la mano de obra de los trabajadores obreros en la etapa de estructuras y se mide la productividad en etapa de arquitectura en el proyecto Edificio Multifamiliar Buganvilias –Tercera Etapa. Conclusiones: La aplicación de una mejora continua en metodologías del Lean Construcción indica que para mejorar las ratios históricas es necesario introducir nuevas tecnologías constructivas para optimizar ratios de mano de obra y de productividad en las obras.Objective: Analyze that the methods of a production management is in Lean Construction used in the stage of structures and architecture in the Construction of the Multifamily Building Buganvillas Stage III produces an impact on the productivity of the work. Methods: Lean Construction methods will be used, use of balance sheets for the measurement of productivity and comparative analysis of the previous proportions of the project for the structure and architecture stage. Results: It was possible to analyze the productivity of the workforce at the stage of the architecture in the project Multifamily Building Buganvilias-Third Stage. Conclusions: The application of a continuous improvement in Lean Construction methodologies indicates that in order to improve historical proportions it is necessary to introduce new construction technologies to optimize proportions of labor and productivity in the works.Trabajo de investigació
Association between xerostomia, oral and general health, and obesity in adults. A cross-sectional pilot study
The objective of this study was to analyse the association between oral and general health variables and obesity indicators with the sensation of dry mouth or xerostomia as evaluated on the Xerostomia Inventory (XI). A total of 354 randomly selected subjects participated in this cross-sectional pilot study and completed an anonymous questionnaire. Anthropometric, clinical, and xerostomic variables were evaluated. Kruskal-Wallis, ANOVA and Bonferroni test were used for multiple comparisons. ROC curves and multinomial logistic regression were used to determine the (OR) risk of xerostomia. A total of 30.7 % of respondents reported xerostomia based on XI. The dry mouth question, the XI taken as a ?gold standard?, showed a diagnostic sensitivity of 70.37 %, and a specificity of 83.27 % (AUC=0.768, p<0.001). Logistical regression showed the highest xerostomia OR was associated to patients with bad self-perceived health, 6.31 (CI 95% 2.89-13.80, p<0.001). In the model adjusted for tooth mobility, bone or respiratory diseases, and the consumption of anxiolytics and antidepressants, the OR was 3.46 (CI 95% 1.47-8.18, p=0.005). a high prevalence of xerostomia was found in this cross-sectional pilot study, which was significantly more frequent in women, and increased with age. Xerostomia was associated to several systemic diseases, psychological conditions, and oral functional disorders such as tooth mobility. These preliminary results can serve as the basis for developing guidelines for the application of innovative measures designed to improve the quality of life of individuals with xerostomia
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