Corrosion behaviour of porous Ti intended for biomedical applications

Porous Ti implants are being developed inorder to reduce the biomechanical mismatch between theimplant and the bone, as well as increasing the osseointegrationby improving the bone in-growth. Most of the focusin the literature has been on the structural, biological andmechanical characterization of porous Ti whereas there islimited information on the electrochemical characterization.Therefore, the present work aims to study the corrosionbehaviour of porous Ti having 30 and 50 % ofnominal porosity, produced by powder metallurgy routeusing the space holder technique. The percentage, size anddistribution of the pores were determined by image analysis.Electrochemical tests consisting of potentiodynamicpolarization and electrochemical impedance spectroscopywere performed in 9 g/L NaCl solution at body temperature.Electrochemical studies revealed that samples presenteda less stable oxide film at increased porosity, morespecifically, the complex geometry and the interconnectivityof the pores resulted in formation of less protectiveoxide film in the pores.This study was supported by FCT with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalizac¸a˜o (POCI) with the reference project POCI-01-0145- FEDER-006941, Programa de Acc¸o˜es Universita´rias Integradas LusoFrancesas’ (PAUILF TC-12_14), and The Calouste Gulbenkian Foundation through ‘‘Programa de Mobilidade Acade´mica para Professores’’. The authors would also like to acknowledge Prof. Ana Senos (University of Aveiro) and Prof. Jose´ Carlos Teixeira (University of Minho) for the provision of the characterization facilities.info:eu-repo/semantics/publishedVersio

Corrosion behaviour of the titanium beta alloy nanotubular surface in the presence of fluoride ions

The titanium bioactivity could be increased by surface nanostructuring. Titanium alloys are using for dental implants manufacturing. It represents a specific problem because of using of the dental treatments with high concentration of fluoride ions and with acidic pH. The corrosion resistance of nanostructured surface of titanium beta alloy in environments with fluoride ions was examined by common electrochemical technique. The electrochemical impedance measurement showed high corrosion resistance in physiological solution. The fluoride ions have expected negative influence on corrosion behaviour of the layer. The nanotube bottom was preferentially attacked which resulted in layer undercoroding and its detachment

Insect pollinators: linking research and policy. Workshop report.

EXECUTIVE SUMMARY Pollinators interact with plants to underpin wider biodiversity, ecosystem function, ecosystem services to agricultural crops and ultimately human nutrition. The conservation of pollinators is thus an important goal. Pollinators and pollination represent a tractable example of how biodiversity can be linked to an ecosystem service. This represents a case study for exploring the impacts of various policy instruments aiming to halt/reverse the loss of ecosystem services. There is a need to understand how multiple pressures (e.g. habitat loss, fragmentation and degradation, climate change, pests and diseases, invasive species and environmental chemicals) can combine or interact to affect diversity, abundance and health of different pollinator groups. Decision makers need to balance consideration of the effects of single pressures on pollinators against the suite of other pressures on pollinators. For instance, the threat from pesticide use (with its high public and media profile) also needs to be considered in the context of the other threats facing pollinators and balanced against the need for food security. An independent review of the balance of risks across pollinator groups from pesticide use would help synthesise current knowledge into an accessible form for decision makers. To manage or lessen these threats to pollinators (wild and managed) and pollination requires improved knowledge about their basic ecology. We still need to know where and in what numbers different pollinator species occur, how they use different environments, how they interact with each other through shared plants and diseases and how wild pollinator abundance is changing. Decision makers need clear factual evidence for i) the relative contribution of different managed and wild pollinator groups to wildflower and crop pollination and ii) how this varies across different land-uses, ecosystems and regions. Addressing these basic and applied questions will improve our ability to forecast impacts on pollination service delivery to agricultural crops arising from current and future environmental changes, pesticide use and emerging diseases. The development of a long-term, multi-scale monitoring scheme to monitor trends in pollinator (wild and managed) population size and delivery of pollination services (ideally tied to data collection on land-use, pesticide applications and disease incidence at relevant spatial scales) would provide the evidence base for developing the effectiveness of policy and management interventions over time. Such a monitoring scheme would benefit from including research council organisations (e.g. CEH), governmental departments (e.g. Fera), universities, museums and NGOs (e.g. BBKA,SBA, Bumblebee Conservation Trust etc) Insect Pollinators: linking research and policy Workshop Report | 5 In the context of agricultural intensification and conservation we need to establish what type, quality and quantity of interventions (e.g. agri-environment schemes, protected areas) are needed, where to place them and how they can sustain different pollinator populations and effective pollination services. Current monitoring of the risks from diseases and pesticides requires broadening to consider other insects aside from honey bees, unless we can demonstrate that honey bees are good surrogates for all other pollinators. There is a need to increase confidence in regulatory risk assessments pertaining to pathogens and pesticides by incorporating other pollinator species, investigating chronic exposure to multiple chemicals and using field relevant dosages (specific to regions, not using other data sources as surrogates). At present the effects of spatial, social and temporal scales on the benefits stakeholders receive from pollination services are only beginning to be understood. Economic valuation of pollination services can help optimise the cost-effectiveness of service management measures and offer new opportunities to incentivise action or raise awareness among stakeholders. Novel tools and instruments (e.g. education and training) are needed to translate broad international (e.g. CBD, EU Biodiversity Strategy) and national (e.g. England‟s Biodiversity Strategy) policies into local actor (e.g. beekeeper, farmer, citizen scientist) contributions to meet biodiversity commitments Refocusing some public funding to link basic science to development of practical solutions (e.g. better crop protection products, improved disease resistance or treatment) could help science deliver better-targeted evidence for pollinator protection. Scientists need to make more use of opportunities (e.g. POSTnotes1; practitioner guides) to transfer knowledge to a broad audience in order to better influence decision maker and practitioner behaviours. Improved knowledge exchange between scientists and decision makers is important to combating threats to pollination. Central to this is improved understanding of the respective positions of policy makers and scientists. For instance, policy-makers usually need to be presented with a range of options to balance against other areas of policy. Science does not always arrive at a consensus due to uncertainties in data or models. Policy-makers need to understand that scientists are communicating the “best available knowledge at present” and that consequently it is not always possible to give a definitive answer

Influence of the magnetic field on microorganisms in the oral cavity

Since the beginning of their lives, all living organisms are exposed to the influence of geomagnetic fields. Objectives : With respect to the positive effects that magnetic fields have on human tissues, especially the bactericidal effect, this investigation aimed to assess their influence on the reduction of oral microorganisms. Material and Methods : In order to obtain adequate specimens of dental plaque deposit, microbes such as Streptococcus parasanguinis, Staphylococcus epidermidis, Rhodococcus equi and Candida albicans were isolated from the human mouth. To establish the intensity of microbial growth on the basis of the modified optical density (OD) of agar turbidimetry assay, microbial count and spectrophotometry were applied. The study was carried out with two microbial concentrations (1 and 10 CFU/ml) after periods of incubation of 24 and 48 h and using micromagnets. Results : A positive effect of the magnetic field, resulting in the reduction of dental plaque microbes in vitro, was found. In the first 24 hours of exposure to the magnetic field, the number of all isolated microbes was significantly reduced. The most potent influence of magnets and the most intensified reduction after 24 hours were evident in Candida albicans colonies. The decrease in the influence of magnets on microbes in vitro was also detected. Conclusions : Magnets reduce the number of microbes and might be recommended as a supplement in therapy for reduced periodontal tissues. This is important because periodontal tissues that are in good conditions provide prolonged support to the oral tissues under partial and supradental denture