Comparison of low.pressure oxygen plasma and chemical treatments for surface modifications of Ti6Al4V

Different treatments were conducted over Ti6Al4V samples in order to produce a surface modification to increase cell attachment and proliferation.The surface treatments evaluated in this study were as follows:etching with sulfuric acid/hydrochloric acid,oxidizing with hydrogen peroxide and low-pressure oxygen plasma treatment.In contrast to other works found in the literature,this research conducts a comparison between different chemical and physical treatments in terms of different assays for surface characterization:X-ray diffraction,scanning electron microscope(SEM),energy-dispersive X-ray spectroscopy,water contact angle,release of vanadium ions and cell viability tests(MTT)of human osteoblasts(hFOB 1.19).Cell morphology over the different substrates was also studied by SEM observation.It was found that plasma and peroxide treatments increase the O/Ti ratio at the titanium surface and provide an increase in cell affinity.On the other hand,acid etching provides a superhydrophilic surface which is not able to improve the cell attachment of human osteoblasts.

Main factors affecting lacertid lizard thermal ecology

The thermal ecology of ectotherms has been studied for almost 2 centuries,but additional attention is current­ly being paid to it,to understand how organisms deal with the environment in a climate change context.A con­sensus is still far away due to the large number of factors involved and their complex interactions.In this con­text,3 analyses in lacertid lizards were carried out:(i)a meta-analysis,to test for differences between body and air temperatures from 71 populations;(ii)a meta-analysis concerning correlations between body and air tem­peratures from 60 populations;and(iii)a multimodel inference of thermoregulation effectiveness indices from 45 populations.The importance of different factors,including body size,habitat,insularity,altitude,climate and season,was evaluated in all analyses to model the response variables.A strong seasonality effect was observed,with a consistent pattern of less effective thermoregulation in summer compared to other seasons.Altitude was the second most important factor,with a consistent higher thermoregulation effort in populations occurring at high elevations(>1000 m above sea level).Other factors,such as insularity or body size,can also be important,but did not exhibit a clear pattern.Finally,thermoregulation was less affected by climate and habitat type.

The role of environmental temperature on movement patterns of giant anteaters

Mammals can show conspicuous behavioral responses to thermal variation,including changes in movement patterns.We used an integrative approach to understand how environmental temperature can drive the movement behavior of a mammal with low capacity for physiological thermoregulation,the giant anteater(Myrmecophaga tridactyla).We tracked 52 giant anteaters in 7 areas throughout the Brazilian savannah.We estimated the distance moved,area used,use of forest areas,and mean environmental temperature for each monitoring day of each individual.We modeled these data with Mixed Structural Equations—considering the possible interactions between our variables and controlling for sex and body mass.Giant anteaters reduced displacement and increased forest use with decreasing environmental temperature,probably because of their low body heat production.It is possible that they reduce distance moved and area used by reducing the duration of activity.With decreasing temperature,forest habitats become warmer than open ones,besides buffer rain and chilly winds.Reducing displacement and using forests are important strategies to reduce body heat loss and the energetic costs of thermoregulation.However,decreasing movement can limit food access and,consequently,fitness.Therefore,we highlight the importance of forests as thermal shelters.With increasing frequency and intensity of extreme weather events,we showed the need to preserve forest patches to offer suitable conditions for tropical mammals’behavioral thermoregulation.In this context,policies favoring deforestation on Brazilian territory are especially worrisome.Finally,we emphasize the need of integrative approaches to understand the complex interactions between organisms and the environment.