Balancing porosity and mechanical properties of titanium samples to favor cellular growth against bacteria

Two main problems limit the success of titanium implants: bacterial infection, which restricts their osseointegration capacity; and the stiffness mismatch between the implant and the host cortical bone, which promotes bone resorption and risk of fracture. Porosity incorporation may reduce this difference in stiffness but compromise biomechanical behavior. In this work, the relationship between the microstructure (content, size, and shape of pores) and the antibacterial and cellular behavior of samples fabricated by the space-holder technique (50 vol % NH4HCO3 and three ranges of particle sizes) is established. Results are discussed in terms of the best biomechanical properties and biofunctional activity balance (cell biocompatibility and antibacterial behavior). All substrates achieved suitable cell biocompatibility of premioblast and osteoblast in adhesion and proliferation processes. It is worth to highlighting that samples fabricated with the 100–200 μm space-holder present better mechanical behavior—in terms of stiffness, microhardness, and yield strength—which make them a very suitable material to replace cortical bone tissues. Those results exposed the relationship between the surface properties and the race of bacteria and mammalian cells for the surface with the aim to promote cellular growth over bacteria.University of Seville (Spain) VI Plan Propio de Investigación y Transferencia—US 2018, I.3A

Master in water engineering a “semi-attendance” university-specific degree with international participation

The Water Engineering Master Course is a university-specific degree at the University of Seville which nowadays can be coursed in two different modalities: “on line” and “semi-attendance”. Its first edition took place at 2000 and since then, the average of graduated students has been of 40 students per course. The semi-attendance mode offers the possibility of being followed in an on-line way from November to June. A Moodle platform provides all the documentation that is required to attend every module, at the end of each one some online questionnaires are also uploaded in order to evaluate the students. Only one of the 10 mandatory modules which make up the course have to be attended in a classroom mode. It takes place during 15 days in July and allows the students to come into contact with the lecturers, professionals of the sector and their own mates as well. During this period both, teachers and students, are lodged in the same residence and all of them have the chance of interchanging experiences in a full teaching-learning process, solving doubts and improving their skills thanks to specific courses, specially designed in function of the lack of knowledge which has been detected during de previous modules, o even, the suggestions received directly from students. Most of the students come from Hispanic countries and in less amount from African and European countries. Actually every July about 80 students and teachers from 25 different countries around the world, meet in Seville to attend this Master. The classes are given in Spanish with translator support if it’s necessary. Different environments, problematic and conditioning factors are studied and a large kind of solutions in water cycle are designed during these days. The requirements to elaborate the final master project are mainly that this one can be used to resolve a real local problem in the student’s origin place and moreover the student can obtain better marks if he/she finds financing to carry it out. In the last 8 years a useful module named “Tools for design” has been included in the program of the Master in order to enable the student in IT, specifically spreadsheets, cad, software for budgeting and measurement, topography and decision support systems. Students who graduate are able to evaluate the most proper technology from a social, technic and economic point of view, as well as, select the most efficient alternatives in order to achieve a sustainable development

Naturalization: a New Concept Developed and Carried Out in the Subject " Environmental Technology " of Degree in Industrial Engineering

Environmental Technology is a 6 credits transversal subject included in the curriculum of all the degrees in Industrial Engineering at the Higher Polytechnic School of the University of Seville. In the last 5 academic courses, the students of this matter have been working with the concept of “Naturalization”. In the different topics which are studied in this subject, they have to apply the naturalization of the systems in order to use natural resources for improving processes. The Naturalization implies improvements in energetic efficiency, development of green spaces and CO2 capture and can be applied the majority of the industrial and urban activities. Some of the most meaningful results that our students have researched are: i) Naturalization of a large pond in a business park in Jaen (Spain) performing its layout and eventually implementing it, using plants to improve water quality and stones for fix them and to give support for bacterial biofilms. The students have improved their skills not only in the increase of new knowledge but in the ability of work in groups and carry out a real project under different points of view. ii) Project of naturalization of a neighbourhood in Seville, based on the increase of green spaces, with vegetal species which are able to capture electromagnetic radiations and CO2 emissions as well. iii) Naturalization of the margins of one lagoon in a park in Seville, transforming the precast panelled walls in breakwater bed of stones planted with bank river plants in order to improve the water quality and the landscape

Sinking Jelly-Carbon Unveils Potential Environmental Variability along a Continental Margin

Particulate matter export fuels benthic ecosystems in continental margins and the deep sea, removing carbon from the upper ocean. Gelatinous zooplankton biomass provides a fast carbon vector that has been poorly studied. Observational data of a large-scale benthic trawling survey from 1994 to 2005 provided a unique opportunity to quantify jelly-carbon along an entire continental margin in the Mediterranean Sea and to assess potential links with biological and physical variables. Biomass depositions were sampled in shelves, slopes and canyons with peaks above 1000 carcasses per trawl, translating to standing stock values between 0.3 and 1.4 mg C m2 after trawling and integrating between 30,000 and 175,000 m2 of seabed. The benthopelagic jelly-carbon spatial distribution from the shelf to the canyons may be explained by atmospheric forcing related with NAO events and dense shelf water cascading, which are both known from the open Mediterranean. Over the decadal scale, we show that the jelly-carbon depositions temporal variability paralleled hydroclimate modifications, and that the enhanced jelly-carbon deposits are connected to a temperature-driven system where chlorophyll plays a minor role. Our results highlight the importance of gelatinous groups as indicators of large-scale ecosystem change, where jelly-carbon depositions play an important role in carbon and energy transport to benthic systems

Environmental controls on modern scleractinian coral and reef-scale calcification

Modern reef-building corals sustain a wide range of ecosystem services because of their ability to build calcium carbonate reef systems. The influence of environmental variables on coral calcification rates has been extensively studied, but our understanding of their relative importance is limited by the absence of in situ observations and the ability to decouple the interactions between different properties. We show that temperature is the primary driver of coral colony (Porites astreoides and Diploria labyrinthiformis) and reef-scale calcification rates over a 2-year monitoring period from the Bermuda coral reef. On the basis of multimodel climate simulations (Coupled Model Intercomparison Project Phase 5) and assuming sufficient coral nutrition, our results suggest that P. astreoides and D. labyrinthiformis coral calcification rates in Bermuda could increase throughout the 21st century as a result of gradual warming predicted under a minimum CO2 emissions pathway [representative concentration pathway (RCP) 2.6] with positive 21st-century calcification rates potentially maintained under a reduced CO2 emissions pathway (RCP 4.5). These results highlight the potential benefits of rapid reductions in global anthropogenic CO2 emissions for 21st-century Bermuda coral reefs and the ecosystem services they provide

Benthic marine calcifiers coexist with CaCO3-undersaturated seawater worldwide

Ocean acidification and decreasing seawater saturation state with respect to calcium carbonate (CaCO3) minerals have raised concerns about the consequences to marine organisms that build CaCO3 structures. A large proportion of benthic marine calcifiers incorporate Mg2+ into their skeletons (Mg-calcite), which, in general, reduces mineral stability. The relative vulnerability of some marine calcifiers to ocean acidification appears linked to the relative solubility of their shell or skeletal mineralogy, although some organisms have sophisticated mechanisms for constructing and maintaining their CaCO3 structures causing deviation from this dependence. Nevertheless, few studies consider seawater saturation state with respect to the actual Mg-calcite mineralogy (ΩMg-x) of a species when evaluating the effect of ocean acidification on that species. Here, a global dataset of skeletal mole % MgCO3 of benthic calcifiers and in situ environmental conditions spanning a depth range of 0 m (subtidal/neritic) to 5600 m (abyssal) was assembled to calculate in situ ΩMg-x. This analysis shows that 24% of the studied benthic calcifiers currently experience seawater mineral undersaturation (ΩMg-x < 1). As a result of ongoing anthropogenic ocean acidification over the next 200 to 3000 years, the predicted decrease in seawater mineral saturation will expose approximately 57% of all studied benthic calcifying species to seawater undersaturation. These observations reveal a surprisingly high proportion of benthic marine calcifiers exposed to seawater that is undersaturated with respect to their skeletal mineralogy, underscoring the importance of using species-specific seawater mineral saturation states when investigating the impact of CO2-induced ocean acidification on benthic marine calcification

Influence of temperature and CO₂ on the strontium and magnesium composition of coccolithophore calcite

Marine calcareous sediments provide a fundamental basis for paleoceanographic studies aiming to reconstruct past oceanic conditions and understand key biogeochemical element cycles. Calcifying unicellular phytoplankton (coccolithophores) are a major contributor to both carbon and calcium cycling by photosynthesis and the production of calcite (coccoliths) in the euphotic zone and the subsequent long-term deposition and burial into marine sediments. Here we present data from controlled laboratory experiments on four coccolithophore species and elucidate the relation between the divalent cation (Sr, Mg and Ca) partitioning in coccoliths and cellular physiology (growth, calcification and photosynthesis). Coccolithophores were cultured under different seawater temperature and carbonate chemistry conditions. The partition coefficient of strontium (DSr) was positively correlated with both carbon dioxide (pCO2) and temperature but displayed no coherent relation to particulate organic and inorganic carbon production rates. Furthermore, DSr correlated positively with cellular growth rates when driven by temperature but no correlation was present when changes in growth rates were pCO2-induced. The results demonstrate the complex interaction between environmental forcing and physiological control on the strontium partitioning in coccolithophore calcite. The partition coefficient of magnesium (DMg) displayed species-specific differences and elevated values under nutrient limitation. No conclusive correlation between coccolith DMg and temperature was observed but pCO2 induced a rising trend in coccolith DMg. Interestingly, the best correlation was found between coccolith DMg and chlorophyll a production suggesting that chlorophyll a and calcite associated Mg originate from the same intracellular pool. These results give an extended insight into the driving factors that lead to variations in the coccolith Mg / Ca ratio and can be used for Sr / Ca and Mg / Ca paleoproxy calibration

Bacterial behavior on coated porous titanium substrates for biomedical applications

In this work, bacterial behavior on dense and porous titanium substrates is discussed. Porous titanium was fabricated by a space holder technique using 50 vol , NH4HCO3 with particle sizes between 250 and 355 amp; 956;m . These substrates were coated by sulfonated PEEK termed SPEEK . Characterization of the porous substrate was carried out using the Archimedes Method, Image Analysis, and three dimensional X ray Micro Computed Tomography including total and interconnected porosity, equivalent diameter, and pore shape factor , as well as mechanical characterization specifically stiffness and yield strength . A detailed study was performed here to investigate the influence of substrate porosity on the adhesion and proliferation of E. coli, MRSA, and P. aeruginosa common causes of orthopedic device associated infections . Bacterial colonization was examined in terms of the initial bacterial concentration, as well as bacterial adherence to and growth on the surface and inside the pores. Results suggest that fully dense titanium supported the least bacterial colonization, while the porous titanium promoted bacterial growth in the medium and inside the cavities. Furthermore, the SPEEK coating deposited onto the samples inhibited bacteria growth inside the porous materials. In this manner, this study showed for the first time that SPEEK could have potential antibacterial properties to offset the increase in bacteria growth commonly observed in porous material

Temperature Modulates Coccolithophorid Sensitivity of Growth, Photosynthesis and Calcification to Increasing Seawater pCO2

Increasing atmospheric CO2 concentrations are expected to impact pelagic ecosystem functioning in the near future by driving ocean warming and acidification. While numerous studies have investigated impacts of rising temperature and seawater acidification on planktonic organisms separately, little is presently known on their combined effects. To test for possible synergistic effects we exposed two coccolithophore species, Emiliania huxleyi and Gephyrocapsa oceanica, to a CO2 gradient ranging from ,0.5–250 mmol kg21 (i.e. ,20–6000 matm pCO2) at three different temperatures (i.e. 10, 15, 20uC for E. huxleyi and 15, 20, 25uC for G. oceanica). Both species showed CO2-dependent optimum-curve responses for growth, photosynthesis and calcification rates at all temperatures. Increased temperature generally enhanced growth and production rates and modified sensitivities of metabolic processes to increasing CO2. CO2 optimum concentrations for growth, calcification, and organic carbon fixation rates were only marginally influenced from low to intermediate temperatures. However, there was a clear optimum shift towards higher CO2 concentrations from intermediate to high temperatures in both species. Our results demonstrate that the CO2 concentration where optimum growth, calcification and carbon fixation rates occur is modulated by temperature. Thus, the response of a coccolithophore strain to ocean acidification at a given temperature can be negative, neutral or positive depending on that strain’s temperature optimum. This emphasizes that the cellular responses of coccolithophores to ocean acidification can only be judged accurately when interpreted in the proper eco-physiological context of a given strain or species. Addressing the synergistic effects of changing carbonate chemistry and temperature is an essential step when assessing the success of coccolithophores in the future ocean

Global variability in seawater Mg:Ca and Sr:Ca ratios in the modern ocean

Seawater Mg:Ca and Sr:Ca ratios are biogeochemical parameters reflecting the Earth–ocean–atmosphere dynamic exchange of elements. The ratios’ dependence on the environment and organisms' biology facilitates their application in marine sciences. Here, we present a measured single-laboratory dataset, combined with previous data, to test the assumption of limited seawater Mg:Ca and Sr:Ca variability across marine environments globally. High variability was found in open-ocean upwelling and polar regions, shelves/neritic and river-influenced areas, where seawater Mg:Ca and Sr:Ca ratios range from ∼4.40 to 6.40 mmol:mol and ∼6.95 to 9.80 mmol:mol, respectively. Open-ocean seawater Mg:Ca is semiconservative (∼4.90 to 5.30 mol:mol), while Sr:Ca is more variable and nonconservative (∼7.70 to 8.80 mmol:mol); both ratios are nonconservative in coastal seas. Further, the Ca, Mg, and Sr elemental fluxes are connected to large total alkalinity deviations from International Association for the Physical Sciences of the Oceans (IAPSO) standard values. Because there is significant modern seawater Mg:Ca and Sr:Ca ratios variability across marine environments we cannot absolutely assume that fossil archives using taxa-specific proxies reflect true global seawater chemistry but rather taxa- and process-specific ecosystem variations, reflecting regional conditions. This variability could reconcile secular seawater Mg:Ca and Sr:Ca ratio reconstructions using different taxa and techniques by assuming an error of 1 to 1.50 mol:mol, and 1 to 1.90 mmol:mol, respectively. The modern ratios’ variability is similar to the reconstructed rise over 20 Ma (Neogene Period), nurturing the question of seminonconservative behavior of Ca, Mg, and Sr over modern Earth geological history with an overlooked environmental effect