Ação do fluoreto de dentifrícios sobre o esmalte dentário.

The possibility of interferring in the dental enamel solubility, reducing significatively the mineral loss, and the possibility of reverting the progress of initial carious lesions turn the fluoride an absolutely necessary element for the oral health. As preventive alternative against caries, the fluoride constitutes of an extremely efficient option for oral public healthcare at low cost. To achieve the purpose of supporting the literature concerning the efficacy of sodium fluoride (NaF), SMFP and of the association between NaF and SMFP present in dentifrices and mouthrinses, the present study aimed to determine in vitro the protection level of the human dental enamel provided by these fluoride forms in presence of pH drop. The rates of calcium removed from the enamel, which had been previously treated, demonstrated these drugs’ protecting action. The experimental results prove that the NaF contained in the test-dentifrice revealed to provide greater enamel protection, despite the lower concentration of this product when compared to the SMFP and to the NaF/SMFP association. These conclusions suggest the relevance of continuing those investigations, due to the importance of obtaining efficient answers by using low concentration of the most effective fluoride form as well as the importance of submitting the different products, frequently introduced to the market, to a quality control process.A possibilidade de intervir na dissolução do esmalte dentário, diminuindo significativamente a perda de minerais, e de reverter o progresso de lesões cariosas iniciais torna o fluoreto um elemento indispensável à saúde dental. Enquanto recurso preventivo, o fluoreto é uma alternativa de saúde pública bucal extremamente eficaz e de baixo custo. Visando subsidiar a literatura que trata da eficácia do fluoreto de sódio (NaF), do monofluorfosfato de sódio (MFP) e da associação entre o fluoreto de sódio e o monofluorfosfato de sódio (NaF/MFP) que integram os dentifrícios, o presente trabalho teve por objetivo determinar, in vitro, o grau de proteção do esmalte dentário humano, assegurado por estas formas de fluoreto, frente à queda do pH. As taxas do cálcio liberado do esmalte previamente tratado, expressas em mg/dl/20min, revelaram o poder protetor destes fármacos. Os resultados experimentais comprovam que o fluoreto de sódio contido no dentifrício teste revelou maior proteção do esmalte, apesar da menor concentração deste fármaco em relação ao monofluorfosfato de sódio e à associação fluoreto de sódio/ monofluorfosfato de sódio, contidos nos demais. Tais conclusões sugerem a continuidade das experimentações, em face da importância de se obterem respostas eficazes, utilizando-se baixas concentrações da forma de fluoreto, comprovadamente mais efetiva, e de se realizar o controle de qualidade dos mais diversos produtos que são lançados no mercado freqüentemente

Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure <= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt

Combined impacts of climate and land use change and the future restructuring of Neotropical bat biodiversity

[Display omitted] •The expansion of bat habitat generalists coupled with range contraction of bat habitat specialist will homogenize the Neotropical bat communities.•Warm-adapted bat species might expand their ranges towards higher altitudes, while mountain-top specialists will run out of suitable climate.•Monitoring programs will be important to track species that are predicted to become extinct and also the projected range expansion of sanguivorous bats.•The most effective way to protect Neotropical bat species will be increasing landscape connectivity and safeguarding the refugia highlighted here. Forecasting the effects of global change on biodiversity is necessary to anticipate the threats operating at different scales in space and time. Climate change may create unsuitable environmental conditions, forcing species to move to persist. However, land-use changes create barriers that limit the access of some species to future available habitats. Here, we project the impacts of climate and land-use change on 228 Neotropical bat species by forecasting changes in environmental suitability, while accounting for the effect of habitat type specialization and simulating dispersal across suitable patches. We also identify the most vulnerable ecoregions and those that may offer future stable refugia. We further investigate potential functional changes by analysing the response of different trophic guilds. We found that the range contraction of habitat specialists, especially frugivores, was more frequent and stronger under all simulated scenarios. Projected changes differ markedly across ecoregions. While the Amazon region is likely to undergo high turnover rates in bat composition, the Andean grassland, Cerrado and Chaco might experience the greatest losses. The expansion of habitat generalists, which forage in open areas and commonly establish large colonies in manmade structures, coupled with the range contraction of habitat specialists is projected to homogenize bat communities across the Neotropics. Overall, dispersal will likely be the key for the future of Neotropical bat diversity. Therefore, safeguarding the refugia highlighted here, by expanding and connecting the existing network of protected areas, for example, may allow species to move in response to global change

Climate change reshapes the eco‐evolutionary dynamics of a Neotropical seed dispersal system

Aim Global changes will redistribute biodiversity, reshaping ecological interactions and ecosystem processes. The decoupling in the distribution of plants and their mutualistic seed dispersers, for instance, may have overlooked eco‐evolutionary effects. How animal‐dispersed plants will respond to changes in the distribution of their seed dispersers remains largely an open question. Here, we forecast the consequences of climate change and frugivory interactions for the spatial distribution and seed size evolution of a Neotropical palm species. Location Atlantic forests of South America. Time period Present day, end of 21st century. Major taxa studied Thirty‐two species of frugivorous birds, and a palm (Euterpe edulis). Methods Future patterns of animal–plant co‐occurrence were derived from ecological niche models, climate forecasts, projections of future forest loss, and seed dispersal simulations. We further explored the evolutionary effect of the spatial reorganization of interactions by modelling palm seed sizes as a function of changes in the distribution of frugivore traits. Results Our models indicate that future climate change and deforestation may reduce the palm’s suitable distribution by 20%–50%. However, our simulations suggest that 66% of all remaining future suitable distribution (76,200 km2) would still be inaccessible to the palm without the active dispersal of seeds by frugivores. In addition, novel frugivore communities are projected to have smaller mean body mass and gape size (−23% and −10%, respectively), due to the loss of large frugivores, which may translate into a 6%–17% reduction of seed sizes across the palm’s remaining distribution. Main conclusions Our projections indicate that frugivore seed dispersal may be critical to allow occupancy of future habitat by animal‐dispersed plants. However, loss of large frugivores may affect trait selection regimes, creating hotspots of plant evolution towards smaller seeds. We argue that such complex dynamics emerging from species‐specific responses to global change may reshape the distribution and evolution of several interacting partners worldwide

The effect of past defaunation on ranges, niches, and future biodiversity forecasts

Humans have reshaped the distribution of biodiversity across the globe, extirpating species from regions otherwise suitable and restricting populations to a subset of their original ranges. Here, we ask if anthropogenic range contractions since the Late Pleistocene led to an under-representation of the realized niches for megafauna, an emblematic group of taxa often targeted for restoration actions. Using reconstructions of past geographic distributions (i.e., natural ranges) for 146 extant terrestrial large-bodied (>44 kg) mammals, we estimate their climatic niches as if they had retained their original distributions and evaluate their observed niche dynamics. We found that range contractions led to a sizeable under-representation of the realized niches of several species (i.e., niche unfilling). For 29 species, more than 10% of the environmental space once seen in their natural ranges has been lost due to anthropogenic activity, with at least 12 species undergoing reductions of more than 50% of their realized niches. Eighteen species may now be confined to low-suitability locations, where fitness and abundance are likely diminished; we consider these taxa 'climatic refugees'. For those species, conservation strategies supported by current ranges risk being misguided if current, suboptimal habitats are considered baseline for future restoration actions. Because most climate-based biodiversity forecasts rely exclusively on current occurrence records, we went on to test the effect of neglecting historical information on estimates of species' potential distribution - as a proxy of sensitivity to climate change. We found that niche unfilling driven by past range contraction leads to an overestimation of sensitivity to future climatic change, resulting in 50% higher rates of global extinction, and underestimating the potential for megafauna conservation and restoration under future climate change. In conclusion, range contractions since the Late Pleistocene have also left imprints on megafauna realized climatic niches. Therefore, niche truncation driven by defaunation can directly affect climate and habitat-based conservation strategies

Assessing Mammal Exposure to Climate Change in the Brazilian Amazon

<div><p>Human-induced climate change is considered a conspicuous threat to biodiversity in the 21^st century. Species’ response to climate change depends on their exposition, sensitivity and ability to adapt to novel climates. Exposure to climate change is however uneven within species’ range, so that some populations may be more at risk than others. Identifying the regions most exposed to climate change is therefore a first and pivotal step on determining species’ vulnerability across their geographic ranges. Here, we aimed at quantifying mammal local exposure to climate change across species’ ranges. We identified areas in the Brazilian Amazon where mammals will be critically exposed to non-analogue climates in the future with different variables predicted by 15 global circulation climate forecasts. We also built a null model to assess the effectiveness of the Amazon protected areas in buffering the effects of climate change on mammals, using an innovative and more realistic approach. We found that 85% of species are likely to be exposed to non-analogue climatic conditions in more than 80% of their ranges by 2070. That percentage is even higher for endemic mammals; almost all endemic species are predicted to be exposed in more than 80% of their range. Exposure patterns also varied with different climatic variables and seem to be geographically structured. Western and northern Amazon species are more likely to experience temperature anomalies while northeastern species will be more affected by rainfall abnormality. We also observed an increase in the number of critically-exposed species from 2050 to 2070. Overall, our results indicate that mammals might face high exposure to climate change and that protected areas will probably not be efficient enough to avert those impacts.</p></div

Data from: Niche conservatism and the invasive potential of the wild boar

1.Niche conservatism, i.e. the retention of a species’ fundamental niche through evolutionary time, is cornerstone for biological invasion assessments. The fact that species tend to maintain their original climate niche allows predictive maps of invasion risk to anticipate potential invadable areas. Unraveling the mechanisms driving niche shifts can shed light on the management of invasive species. 2.Here, we assessed niche shifts in one of the world's worst invasive species: the wild boar Sus scrofa. We also predicted potential invadable areas based on an ensemble of three ecological niche modeling methods, and evaluated the performance of models calibrated with native vs pooled (native plus invaded) species records. By disentangling the drivers of change on the exotic wild boar population's niches, we found strong evidence for niche conservatism during biological invasion. 3.Ecological niche models calibrated with both native and pooled range records predicted convergent areas. Also, observed niche shifts are mostly explained by niche unfilling, i.e. there are unoccupied areas in the exotic range where climate is analogous to the native range. 4.Niche unfilling is expected as result of recent colonization and ongoing dispersal, and was potentially stronger for the Neotropics, where a recent wave of introductions for pig-farming and game-hunting has led to high wild boar population growth rates. The invasive potential of wild boar in the Neotropics is probably higher than in other regions, which has profound management implications if we are to prevent their invasion into species-rich areas, such as Amazonia, coupled with expansion of African swine fever and possibly great economic losses. 5.Although the originally Eurasian-wide distribution suggests a pre-adaptation to a wide array of climates, the wild boar worldwide invasion does not exhibit evidence of niche evolution. The invasive potential of the wild boar therefore probably lies on the reproductive, dietary and morphological characteristics of this species, coupled with behavioral thermoregulation

Current and future climate conditions (average and standard deviation) in Brazilian Amazon.

<p>The number of critically-exposed mammals (species with more than 80% of their range exposed) exposed to different climatic variables separately and taken together are showed. These results were quantified using an average of 15 General Circulation Models for a high-emission greenhouse gases scenario (RCP 8.5) for 2050 and 2070.</p