Role of extracellular DNA in Enterococcus faecalis biofilm formation and its susceptibility to sodium hypochlorite

Objective: This study investigated the role of extracellular deoxyribonucleic acid (eDNA) on Enterococcus faecalis ( E. faecalis ) biofilm and the susceptibility of E. faecalis to sodium hypochlorite (NaOCl). Methodology: E. faecalis biofilm was formed in bovine tooth specimens and the biofilm was cultured with or without deoxyribonuclease (DNase), an inhibitor of eDNA. Then, the role of eDNA in E. faecalis growth and biofilm formation was investigated using colony forming unit (CFUs) counting, eDNA level assay, crystal violet staining, confocal laser scanning microscopy, and scanning electron microscopy. The susceptibility of E. faecalis biofilm to low (0.5%) or high (5%) NaOCl concentrations was also analyzed by CFU counting. Results: CFUs and biofilm formation decreased significantly with DNase treatment (p<0.05). The microstructure of DNase-treated biofilms exhibited less structured features when compared to the control. The volume of exopolysaccharides in the DNase-treated biofilm was significantly lower than that of control (p<0.05). Moreover, the CFUs, eDNA level, biofilm formation, and exopolysaccharides volume were lower when the biofilm was treated with DNase de novo when compared to when DNase was applied to matured biofilm (p<0.05). E. faecalis in the biofilm was more susceptible to NaOCl when it was cultured with DNase (p<0.05). Furthermore, 0.5% NaOCl combined with DNase treatment was as efficient as 5% NaOCl alone regarding susceptibility (p>0.05). Conclusions: Inhibition of eDNA leads to decrease of E. faecalis biofilm formation and increase of susceptibility of E. faecalis to NaOCl even at low concentrations. Therefore, our results suggest that inhibition of eDNA would be beneficial in facilitating the efficacy of NaOCl and reducing its concentration

Enhanced antioxidant effect of trans-resveratrol: potential of binary systems with polyethylene glycol and cyclodextrin.

Abstract Trans-resveratrol, a polyphenol extracted from Vitis vinifera, has different beneficial effects following its administration on the skin. Here the potential use of binary systems to enhance in vitro and in vivo activity of trans-resveratrol was investigated. Thus the aqueous solubility of trans-resveratrol was investigated in the presence of growing concentrations of polyethylene glycol (PEG) or β-cyclodextrin (βCD) as solubilizing excipients. Then, the solid dispersion of trans-resveratrol with PEG or inclusion complexes trans-resveratrol/βCD were prepared and characterised by different methods. Cytotoxicity and inhibition of reactive oxygen species (ROS) following H2O2 challenge in the presence of trans-resveratrol, alone or associated to the excipients, was evaluated on human keratinocyte HaCaT cell line. Both the trans-resveratrol-containing binary systems induced significant reduction of H2O2-induced ROS production, especially in the case of βCD that was selected for the following phase of the study. Thus, the effect of a cream containing trans-resveratrol, alone or associated to βCD, on different skin parameters such as corneometry, colorimetry and elastometry, was evaluated on human volunteers. All patients showed a visible improvement of clinical conditions with a remarkable decrease of aging signs, but this effect was higher of the hemi face treated with the βCD-containing formulation versus formulation containing trans-resveratrol alone

Effect of a calcium hydroxide-based intracanal medicament containing N-2-methyl pyrrolidone as a vehicle against Enterococcus faecalis biofilm

This study investigated the effect of a calcium hydroxide (CH) paste (CleaniCal®) containing N-2-methyl pyrrolidone (NMP) as a vehicle on Enterococcus faecalis (E. faecalis) biofilms compared with other products containing saline (Calasept Plus™) or propylene glycol (PG) (Calcipex II®). Methodology: Standardized bovine root canal specimens were used. The antibacterial effects were measured by colony-forming unit counting. The thickness of bacterial microcolonies and exopolysaccharides was assessed using confocal laser scanning microscopy. Morphological features of the biofilms were observed using field-emission scanning electron microscopy (FE-SEM). Bovine tooth blocks covered with nail polish were immersed into the vehicles and dispelling was observed. The data were analyzed using one-way analysis of variance and Tukey tests (p<0.05). Results: CleaniCal® showed the highest antibacterial activity, followed by Calcipex II® (p<0.05). Moreover, NMP showed a higher antibacterial effect compared with PG (p<0.05). The thickness of bacteria and EPS in the CleaniCal® group was significantly lower than that of other materials tested (p<0.05). FE-SEM images showed the specimens treated with Calasept Plus™ were covered with biofilms, whereas the specimens treated with other medicaments were not. Notably, the specimen treated with CleaniCal® was cleaner than the one treated with Calcipex II®. Furthermore, the nail polish on the bovine tooth block immersed in NMP was completely dispelled. Conclusions: CleaniCal® performed better than Calasept Plus™ and Calcipex II® in the removal efficacy of E. faecalis biofilms. The results suggest the effect might be due to the potent dissolving effect of NMP on organic substances

Optimización del ciclo de vida de los paneles fotovoltaicos

El presente trabajo ha estudiado la potencial optimización de los recursos naturales dentro del ciclo de vida de los paneles fotovoltaicos, basados en celdas de silicio monocristalinas (las cuales representan un importante porcentaje del mercado, mayor del 30%). En particular, se analizó la conveniencia de reciclar el vidrio y el aluminio que constituyen la estructura de los paneles y cuyos respectivos procesos de recuperación se encuentran ampliamente desarrollados y difundidos, obteniéndose un considerable ahorro de materias primas y energía.This work studies the potential optimization of natural resources in the life cycle of photovoltaic panels based on monocrystalline silicon cells. Particularly the convenience of glass and aluminum recycle has been analyzed, whose recovery process are widely made known and developed, getting a considerable saving of raw materials and energy.Tema 4: Energía solar y conversión fotovoltaica.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Modeling Magnification and Anisotropy in the Primate Foveal Confluence

A basic organizational principle of the primate visual system is that it maps the visual environment repeatedly and retinotopically onto cortex. Simple algebraic models can be used to describe the projection from visual space to cortical space not only for V1, but also for the complex of areas V1, V2 and V3. Typically a conformal (angle-preserving) projection ensuring local isotropy is regarded as ideal and primate visual cortex is often regarded as an approximation of this ideal. However, empirical data show systematic deviations from this ideal that are especially relevant in the foveal projection. The aims of this study were to map the nature of anisotropy predicted by existing models, to investigate the optimization targets faced by different types of retino-cortical maps, and finally to propose a novel map that better models empirical data than other candidates. The retino-cortical map can be optimized towards a space-conserving homogenous representation or a quasi-conformal mapping. The latter would require a significantly enlarged representation of specific parts of the cortical maps. In particular it would require significant enlargement of parafoveal V2 and V3 which is not supported by empirical data. Further, the recently published principal layout of the foveal singularity cannot be explained by existing models. We suggest a new model that accurately describes foveal data, minimizing cortical surface area in the periphery but suggesting that local isotropy dominates the most foveal part at the expense of additional cortical surface. The foveal confluence is an important example of the detailed trade-offs between the compromises required for the mapping of environmental space to a complex of neighboring cortical areas. Our models demonstrate that the organization follows clear morphogenetic principles that are essential for our understanding of foveal vision in daily life

Impacto ambiental producido por residuos plásticos

Este trabajo presenta el estudio de los procesos de producción que involucran al plástico como materia prima y la búsqueda de alternativas que permitan disminuir el volumen del material plástico desechado, y al mismo tiempo no sólo minimizar los problemas originados por su disposición final, sino también reutilizarlos como fuente de materia prima y/o energía.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Antimicrobial consumption at the hospital level in latin america. Similarities and differences according to each country

One of the main problems for health service around the world is the antimicrobial resistance (AMR). Objective: to describe the antimicrobial consumption (AMC) at hospital level in Latin American countries and compare the amount and type of antibiotics usage among them in order to guide local public health actions towards AMR prevention.Design: A descriptive study of antimicrobial consumption at hospital level among six health institution in Latin America with an analytical comparative stage. Antimicrobials included corresponded to the WHO Anatomical Therapeutic Chemical (ATC) classification system subgroups: J01, A07A and P01AB. Methods: WHO GLASS methodology was applied for surveillance of AMC, using the ATC classification based on Defined Daily Dose (DDD) and DDD/100 hospital discharges as standard unit of measurement. Antimicrobials consumed were also classified according to the WHO AccessWatch-Reserve (AWaRe) classification. Results: The quantitative data, measured in DDD/100 hospital discharges, showed a wide range of consumption (182.48 - 2260.95). Qualitative analysis according to the AWaRe classification also showed a wide range in terms of consumption of Access (38.14% - 73.64%), Watch (24.93% - 60 .53%) and Reserve (0.31% - 3.55%) groups expressed as a percentage of the total consumption.Conclusion: Great heterogeneity and arbitrariness exist in the selection of antimicrobials for hospital use. Although this situation might be explained on local antimicrobial resistance, the history of prescription, local pharmaceutical promotion, and pharmacological education of health professional in each country, particular habits and distinctive culture may justify the differential consumption patterns observed in each institution in this study.Fil: Marin, Gustavo Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Giangreco, Luis. Universidad Nacional de La Plata; ArgentinaFil: Hernández, Yago. Universidad Nacional de La Plata; ArgentinaFil: Dorati, Cristian. Universidad Nacional de La Plata; ArgentinaFil: Mordujovich Buschiazzo, Perla. Universidad Nacional de La Plata; ArgentinaFil: Bay, María Rosa. Hospital Interzonal General de Agudos San Roque - Mb Gonnet ; Gobierno de la Provincia de Buenos Aires;Fil: Gonzalez, Gladys María Adriana. Hospital Interzonal General de Agudos San Roque - Mb Gonnet ; Gobierno de la Provincia de Buenos Aires;Fil: Aldunate, Francisca. Pontificia Universidad Católica de Chile; ChileFil: López Peña, Mónica. Ministerio de Salud y Protección Social; ColombiaFil: Martínez Parra, Adriana. Ministerio de Salud y Protección Social; ColombiaFil: Ching Fung, Shing Mi. Costa Rican social security; Costa RicaFil: Alfonso Arvez, María José. Ministry of Public Health and Social Welfare; ParaguayFil: Mantilla Ponte, Hilda. General Directorate of Medicines, Supplies and Drugs; PerúFil: Marin, Danini. General Directorate of Medicines, Supplies and Drugs; PerúFil: Rojas, Robin. General Directorate of Medicines, Supplies and Drugs; PerúFil: Castro, José Luis. Pan-American Health Organization; Estados Unido

Energy-efficient full-range oscillation analysis of parallel-plate electrostatically actuated MEMS resonators

This is the peer reviewed version of the following article: “Fargas Marques, A., Costa Castelló, R. (2017) Energy-efficient full-range oscillation analysis of parallel-plate electrostatically actuated MEMS resonators, 1-13.” which has been published in final form at [doi: 10.1007/s11071-017-3633-8]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."Electrostatic parallel-plate actuators are a common way of actuating microelectromechanical systems, both statically and dynamically. Nevertheless, actuation voltages and oscillations are limited by the nonlinearity of the actuator that leads to the pull-in phenomena. This work presents a new approach to obtain the electrostatic parallel-plate actuation voltage, which allows to freely select the desired frequency and amplitude of oscillation. Harmonic Balance analysis is used to determine the needed actuation voltage and to choose the most energy-efficient actuation frequency. Moreover, a new two-sided actuation approach is presented that allows to actuate the device in all the stable range using the Harmonic Balance Voltage.Peer ReviewedPostprint (author's final draft