9 research outputs found

    Interactions between wear and corrosion on cast and sintered Ti-12Nb alloy in comparison with the commercial Ti-6Al-4V alloy

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    This work investigates the corrosion and tribocorrosion behavior of alpha + beta Ti-12Nb alloy processed by casting and sintering, in 9 g/l NaCl solution at body temperature, and compares the results with the commercial Ti-6Al-4 V alloy. Different electrochemical techniques were used to access the corrosion behavior. Tribocorrosion behavior was studied at open circuit potential under continuous and intermittent sliding, and at anodic potentiostatic condition under continuous sliding. Results revealed that Ti-12Nb alloys presented similar tribocorrosion behavior although the sintered one exhibited a better corrosion behavior. Nevertheless, Ti-6Al-4 V presented better overall degradation resistance than both Ti-12Nb alloys.- This work was supported by FCT national funds, under the national support to R&D units grant, through the reference project UIDB/04436/2020 and UIDP/04436/2020, together with M-ERA-NET/0001/2015, and co-supported by Brazilian agencies CNPq [grants #308.204/2017-4 and #125.954/2018-2] and FAPESP M-ERA-NET [grant #2015/50.280-5], also by MINECO (Spain) through the program PCIN-2016-123 and the Ramon y Cajal project RYC-2014-15014. I. Caha is grateful for a PhD grant under the NORTE-08-5369-FSE-000012 project

    Intrinsic denervation of the colon is associated with a decrease of some colonic preneoplastic markers in rats treated with a chemical carcinogen

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    Denervation of the colon is protective against the colon cancer; however, the mechanisms involved are unknown. We tested the hypothesis that the denervated colonic mucosa could be less responsive to the action of the chemical carcinogen dimethylhydrazine (DMH). Three groups of 32 male Wistar rats were treated as follows: group 1 (G1) had the colon denervated with 0.3 mL 1.5 mM benzyldimethyltetradecylammonium (benzalkonium chloride, BAC); G2 received a single ip injection of 125 mg/kg DMH; G3 was treated with BAC + the same dose and route of DMH. A control group (Sham, N = 32) did not receive any treatment. Each group was subdivided into four groups according to the sacrifice time (1, 2, 6, and 12 weeks after DMH). Crypt fission index, ß-catenin accumulated crypts, aberrant crypt foci, and cell proliferation were evaluated and analyzed by ANOVA and the Student t-test. G3 animals presented a small number of aberrant crypt foci and low crypt fission index compared to G2 animals after 2 and 12 weeks, respectively. From the second week on, the index of ß-catenin crypt in G3 animals increased slower than in G2 animals. From the 12th week on, G2 animals presented a significant increase in cell proliferation when compared to the other groups. Colonic denervation plays an anticarcinogenic role from early stages of colon cancer development. This finding can be of importance for the study of the role of the enteric nervous system in the carcinogenic process

    Sombreamento de cafeeiros durante o desenvolvimento das gemas florais e seus efeitos sobre a frutificação e produção Shading of coffee plants during floral buds development and its effects on fructification and production

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    O objetivo neste trabalho foi avaliar a influência do sombreamento, durante o período de desenvolvimento de gemas florais, sobre o desenvolvimento e maturação dos frutos, produção e tamanho dos grãos de Coffea arabica L. O experimento foi conduzido com cafeeiros adultos no Município de Londrina, os quais foram sombreados nos meses de abril, maio, junho, julho e agosto de 2004, com malhas de sombrite com 50% de sombreamento. As coberturas foram retiradas, simultaneamente, no início de outubro do mesmo ano. A interceptação de 50% da radiação incidente sobre o dossel dos cafeeiros em diferentes épocas do desenvolvimento de gemas florais não alterou o crescimento e o desenvolvimento dos frutos. As altas temperaturas e a deficiência hídrica anteciparam a maturação dos frutos, porém sem diferenças significativas nos estádios de maturação entre os tratamentos. O sombreamento, em diferentes épocas, também não afetou a produção e o tamanho dos grãos.<br>The objective of this paper was to evaluate the influence of shading during the period of floral buds development on the growth and maturation of coffee fruits, production and grain size of Coffea arabica L. The experiment was carried out in Londrina, PR, Brazil. Plots of adult coffee plants were shaded monthly in April, May, June, July and August of 2004 using shading screens with 50% of porosity. The coverings were removed simultaneously at the beginning of October of the same year. The interception of 50% of incident radiation over the coffee canopy in different periods of floral buds development did not alter fruit growth and development. Fruit maturation was anticipated due to high temperatures and water deficit, however without significant differences on maturation periods among treatments. Grain yield and size were not affected by shading in the different periods

    A window to the sea: environmental indicators for NW-Iberian coastal risk management under the RAIA observatory

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    The international RAIA Observatory (www.marnaraia.org) resulted from the effort of 12 research and academic institutions and public agencies (Spanish and Portuguese) working in the field of meteorology and oceanography. The RAIA Observatory serves the main maritime activities of the Galicia-Northern Portugal Euroregion and contributes to collaborative observational networks. Under the framework of coastal risk management, environmental indicators are fundamental tools for the evaluation and mitigation of environmental risks, showing the current state and helping to predict future changes on ecosystem health regarding environmental risks. In last years, the different partners of the RAIA Observatory have identified 38 environmental indicators, in which 12 key risks affecting the ecosystem services of the Euroregion Galicia-Northern Portugal are being evaluated. Data was analyzed and compiled by the various partners of the RAIA Observatory and the development and optimization of the environmental indicators has been done according to the specifications provided by the European Environmental Agency (EEA) and the International Panel for Climate Change (IPCC). The resulting environmental indicators are included and shared on a publicly-accessible Web service, georeferenced and accompanied by graphics (https://marrisk.inesctec.pt/public/#!/indicators). So far, the current status of the indicators has allowed us to establish risk assessment protocols for the Euroregion, and identify critical gaps in temporal and spatial coverage. The inclusion of the environmental indicators in the RAIA Observatory is of great relevance for national and international data exchange and promotes future collaborations.Interreg POCTEP Spain Portugal, 0262 MARRISK 1

    Long-term variations in Ibero-Atlantic sardine (Sardina pilchardus) population dynamics: Relation to environmental conditions and exploitation history

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    In the current work we modeled the relationship between global atmospheric indices, seasonal sea surface temperature and coastal upwelling on the recruitment of the Ibero-Atlantic sardine. To study long-term Ibero-Atlantic sardine population dynamics a historical recruitment index (HRI) was developed from 1947 to 2012, for the Portuguese west coast, the main recruitment area of the Ibero-Atlantic sardine stock. HRI was calculated as the number of individuals <= 16.0 cm total length per landed kg using length and weight distribution data from purse-seine fleet landings. Recruitment periodicity changed after the late 1960s from 2-3 years to 4 years cycles. Atlantic Multidecadal Oscillation (AMO), summer North Atlantic Oscillation (NAO), summer sea surface temperatures (SST) and winter upwelling were significantly related with recruitment, explaining 45.9% of recruitment variability in the generalized additive model. Possible mechanisms leading to those relationships were discussed. A complex two-way relationship between the sardine exploitation and recruitment appears to exist. High recruitments allowed the increase in total landings in the following years but high exploitation periods may have also led to a decrease of the population potential productivity in the subsequent years. (C) 2016 Elsevier B.V. All rights reserved

    Variations in seasonal solar insolation are associated with a history of suicide attempts in bipolar I disorder

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    Background: Bipolar disorder is associated with circadian disruption and a high risk of suicidal behavior. In a previous exploratory study of patients with bipolar I disorder, we found that a history of suicide attempts was associated with differences between winter and summer levels of solar insolation. The purpose of this study was to confirm this finding using international data from 42% more collection sites and 25% more countries. Methods: Data analyzed were from 71 prior and new collection sites in 40 countries at a wide range of latitudes. The analysis included 4876 patients with bipolar I disorder, 45% more data than previously analyzed. Of the patients, 1496 (30.7%) had a history of suicide attempt. Solar insolation data, the amount of the sun’s electromagnetic energy striking the surface of the earth, was obtained for each onset location (479 locations in 64 countries). Results: This analysis confirmed the results of the exploratory study with the same best model and slightly better statistical significance. There was a significant inverse association between a history of suicide attempts and the ratio of mean winter insolation to mean summer insolation (mean winter insolation/mean summer insolation). This ratio is largest near the equator which has little change in solar insolation over the year, and smallest near the poles where the winter insolation is very small compared to the summer insolation. Other variables in the model associated with an increased risk of suicide attempts were a history of alcohol or substance abuse, female gender, and younger birth cohort. The winter/summer insolation ratio was also replaced with the ratio of minimum mean monthly insolation to the maximum mean monthly insolation to accommodate insolation patterns in the tropics, and nearly identical results were found. All estimated coefficients were significant at p &lt; 0.01. Conclusion: A large change in solar insolation, both between winter and summer and between the minimum and maximum monthly values, may increase the risk of suicide attempts in bipolar I disorder. With frequent circadian rhythm dysfunction and suicidal behavior in bipolar disorder, greater understanding of the optimal roles of daylight and electric lighting in circadian entrainment is needed. © 2021, The Author(s)
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