Non-minimal coupling, exponential potentials and the w<−1w<-1 regime of dark energy

Recent observations and theoretical considerations have motivated the study of models for dark energy with equation of state characterized by a parameter $w=p/\rho<-1$. Such models, however, are usually believed to be inviable due to their instabilities against classical perturbations or potentially catastrophic vacuum decays. In this paper, we show that a simple quintessential model with potential $V(\phi)=Ae^{-\sigma\phi}$ and a gravitational coupling of the form $(1+|\xi|\phi^2)R$ can exhibit, for large sets of initial conditions, asymptotic de Sitter behavior with $w<-1$ regimes. Nevertheless, the model is indeed stable at classical and quantum level.Comment: 5 pages, 4 figure

Fluoride varnishes containing calcium glycerophosphate: fluoride uptake and the effect on in vitro enamel erosion

OBJECTIVES Calcium glycerophosphate (CaGP) was added to fluoride varnishes to analyze their preventive effect on initial enamel erosion and fluoride uptake: potassium hydroxide (KOH)-soluble and KOH-insoluble fluoride bound to enamel. MATERIALS AND METHODS This study was carried out in two parts. Part 1: 108 enamel samples were randomly distributed into six varnish groups: base varnish (no active ingredients); Duraphat® (2.26 %NaF); Duofluorid® (5.63 %NaF/CaF2); experimental varnish 1 (1 %CaGP/5.63 %NaF/CaF2); experimental varnish 2 (5 %CaGP/5.63 %NaF/CaF2); and no varnish. Cyclic demineralization (90 s; citric acid, pH = 3.6) and remineralization (4 h) was made once a day, for 3 days. Change in surface microhardness (SMH) was measured. Part 2: 60 enamel samples were cut in half and received no varnish (control) or a layer of varnish: Duraphat®, Duofluorid®, experimental varnishes 1 and 2. Then, KOH-soluble and KOH-insoluble fluoride were analyzed using an electrode. RESULTS After cyclic demineralization, SMH decreased in all samples, but Duraphat® caused less hardness loss. No difference was observed between varnishes containing CaGP and the other varnishes. Similar amounts of KOH-soluble and insoluble fluoride was found in experimental varnish 1 and Duofluorid®, while lower values were found for experimental varnish 2 and Duraphat®. CONCLUSION The addition of CaGP to fluoride varnishes did not increase fluoride bound to enamel and did not enhance their protection against initial enamel erosion. CLINICAL RELEVANCE We observe that the fluoride varnishes containing CaGP do not promote greater amounts of fluoride bound to enamel and that fluoride bound to enamel may not be closely related to erosion prevention

Leishmania braziliensis exosomes activate human macrophages to produce proinflammatory mediators

Exosomes, organelles measuring 30-200nm, are secreted by various cell types. Leishmania exosomes consist of many proteins, including heat shock proteins, annexins, Glycoprotein 63, proteins exerting signaling activity and those containing mRNA and miRNA. Studies have demonstrated that Leishmania donovani exosomes downregulate IFN-γ and inhibit the expression of microbicidal molecules, such as TNF and nitric oxide, thus creating a microenvironment favoring parasite proliferation. Despite lacking immunological memory, data in the literature suggest that, following initial stimulation, mononuclear phagocytes may become “trained” to respond more effectively to subsequent stimuli. Here we characterized the effects of macrophage sensitization using L. braziliensis exosomes prior to infection by the same pathogen. Human macrophages were stimulated with L. braziliensis exosomes and then infected with L. braziliensis. Higher levels of IL-1β and IL-6 were detected in cultures sensitized prior to infection compared to unstimulated infected cells. Moreover, stimulation with L. braziliensis exosomes induced macrophage production of IL-1β, IL-6, IL-10 and TNF. Inhibition of exosome secretion by L. braziliensis prior to macrophage infection reduced cytokine production and produced lower infection rates than untreated infected cells. Exosome stimulation also induced the consumption/regulation of NLRP3 inflammasome components in macrophages, while the blockade of NLRP3 resulted in lower levels of IL-6 and IL-1β. Our results suggest that L. braziliensis exosomes stimulate macrophages, leading to an exacerbated inflammatory state that may be NLRP3-dependent

Fishing Gear Modifications to Reduce Elasmobranch Mortality in Pelagic and Bottom Longline Fisheries Off Northeast Brazil

One of the biggest challenges of fisheries research is reducing the bycatch of unwanted species. The incidental fishing mortality of species with low reproductive rates, such as elasmobranchs (sharks, skates, and rays), is recognized as a key threat for their populations. In the present study, gear modifications related to the type of hook and position of the hook in the water column were tested to examine their effects on catch rates and mortality of elasmobranch species in both pelagic and coastal environments. Comparisons between circle (size 18/0, 0° offset) and J-style (size 9/0, 10° offset) hooks demonstrated that the circle hooks have a greater efficiency in reducing the mortality of most species caught, both in pelagic and coastal longline fisheries. Internal lodging of the hook was significantly less frequent for the individuals caught with circle hooks, which likely contributed to their higher survival rate at haulback. Additionally, circle hooks also increased the CPUE of elasmobranchs caught in the pelagic longline fishery, which was particularly evident for Carcharhinus falciformis and Prionace glauca. The position of the hook in the water column exhibited a strong influence on the species caught in the coastal bottom longline fishery. Suspending hooks in the middle of the water column reduced the bycatch of common demersal species, such as Carcharhinus acronotus, Ginglymostoma cirratum, and Dasyatis americana, while increasing the CPUE of potentially aggressive species, such as Galeocerdo cuvier and Carcharhinus leucas. The interaction of the type of hook utilized with its position in the water column appears to be an essential factor in the optimization of longline selectivity and minimization of bycatch mortality

Sealing Capability and SEM Observation of the Implant-Abutment Interface

To evaluate the sealing capability of external hexagon implant systems and assess the marginal fit, two groups (n = 10 each) were employed: SIN (Sistema de Implantes Nacional, Brazil) and Osseotite, (Biomet 3i, USA). Sealing capability was determined by placing 0.7 μL of 1% acid-red solution in the implant wells before the torque of their respective abutments. Specimens were then placed into 2.5 mL vials filled with 1.3 mL of distilled water with the implant-abutment interface submerged. Three samples of 100 μL water were collected at previously determinate times. The absorbance was measured with a spectrophotometer, and the data were analyzed by Two-way ANOVA (P < .05) and Tukey's test. Marginal fit was determined using SEM. Leakage was observed for both groups at all times and was significantly higher at 144 hrs. SEM analysis depicted gaps in the implant-abutment interface of both groups. Gaps in the implant-abutment interface were observed along with leakage increased at the 144 hrs evaluation period

Intersetorialidade e potenciais conflitos de interesse entre governos e setor privado comercial no âmbito das ações de alimentação e nutrição para o enfrentamento de doenças crônicas não transmissíveis

This article analyzed the potential conflicts of interest between government and private commercial sectors in the area of food and nutrition (FN) activities within the context of intersectoral proposals for dealing with chronic non-communicable diseases (CNCD) in Brazil. To this end, academic articles and institutional documents published after 2000 were identified that addressed FN actions in CNCD policies guided by intersectoriality. Elements that contributed to understanding the potential conflicts of interest between governments and the private, commercial sector within the context of intersectoral strategies to deal with CNCD were prioritized. It was concluded that the principle of intersectoriality disassociated from a political process that complicates the eligibility criteria and institutional practices of the sectors responsible for the set of actions that comprise government policies may serve as facilitators for favoring commercial interests. Participation in the decision-making process of the sectors of commercial interest whose practices, driven by increased demand for their products and the progressive concentration of power, contradict the purposes and principles of public policy, may delay, reduce, or prevent effective actions to reduce CNCD. This possibility is particularly relevant in the context of attributions that are specific to government entities, especially regulatory strategies.Neste artigo foram analisados os potenciais conflitos entre interesses governamentais e privados de caráter comercial em torno das ações de alimentação e nutrição (AN) no âmbito de propostas intersetoriais de enfrentamento das DCNT no Brasil. Para tal, foram identificados artigos acadêmicos e documentos institucionais publicados a partir de 2000 que abordassem as ações de AN em políticas de DCNT pautadas pela intersetorialidade. Foram priorizados elementos que contribuíssem para a compreensão dos potenciais conflitos de interesse entre governos e o setor privado comercial no âmbito de estratégias intersetoriais de enfrentamento de DCNT. Concluiu-se que o princípio da intersetorialidade, desassociado de um processo político que problematize os critérios de eleição e as práticas institucionais dos setores que respondem pelo conjunto de ações que compõe as políticas governamentais, pode servir como facilitador do favorecimento de interesses comerciais. A participação no processo decisório de setores de interesse comercial cujas práticas ferem objetivos e princípios das políticas públicas, movidos pela expansão da demanda por seus produtos e pela concentração progressiva de poder, pode retardar, atenuar ou impedir ações efetivas na redução de DCNT. Esta possibilidade é particularmente relevante no âmbito de atribuições que são próprias aos entes Estatais, especialmente as estratégias regulatórias