Respostas de duas espécies invertebradas aquáticas às nanopartículas baseadas em carbono sob o cenário de mudanças climáticas

According to recent reports, increases in water acidification and changes in seawater salinity are predicted to occur in the next 100 years. The increase of atmospheric CO2 already caused a pH reduction in surface waters by more than 0.1 units below the pre-industrial average of 8.1, and it is expected to decrease between -0.13 and -0.43 units by the end of this century. Climate change can also occur through alterations in seawater salinity. Warmer temperatures and reduced rainfall increase seawater salinity, while extreme rainy events decrease seawater salinity. Both situations will promote species responses. Therefore, identifying the effects of predicted climate change in aquatic ecosystems must be a priority in order to maintain their biodiversity. Aside from climate change, there is an increasing concern about the large number of emerging pollutants that have been released into the environment without yet being regulated. Among these emerging pollutants are Engineered nanoparticles (ENPs). One of the types of ENPs that are most commonly used in recent years are Carbon Nanotubes (CNTs). Due to their unique chemical and nanotoxicological properties, it is expected that CNTs enter aquatic environments and accumulate in aquatic biota. As a matter of fact, CNTs toxicology in aquatic systems is complex. In the first instance particle size, shape, chemistry and capping agents will all play a role regarding the stability, and thus bioavailability. However, nanomaterial toxicity not only has been attributed to core structure and surface modification/functionalization, but also by the physico-chemical parameters of the media where the CNTs are presented, altering their dispersion and consequently their detection: aggregation/disaggregation, adsorption/desorption, sedimentation/resuspension and dissolution. Several works have described their impacts in the aquatic environment; however, no information is known on how predicted Climate Change could alter the CNT’s toxicity and their effects on marine organisms. Benthic species are a good model to evaluate the impacts of Climate Change and ENPs as they are sensitive to several environmental constrains. Essentially due to their life-history characteristics, as well as their relatively rapid response to pollution, several studies have been using benthic species as bioindicators for anthropogenic and natural stresses. Thus, the evaluation of the impacts of CNTs, under salinity changes and pH reduction on aquatic organisms is an urgent issue needing attention. Particularly, Ruditapes philippinarum (bivalve), Hediste diversicolor and Diopatra neapolitana (polychaetes) have been identified by several authors as a group of marine invertebrates that respond quickly to environmental disturbances, with a wide spatial distribution and economic relevance, namely in Portugal. Thus, the present proposal evaluated the toxic effects in terms of biochemical (energy reserves and metabolic activity, oxidative and neuro status) and physiological responses (regenerative capacity) in the cited species of salinity shifts and pH variation and the presence of CNTs acting along and in combinations. The two CNT materials selected in the present study were the pristine multi walled carbon nanotubes (Nf-MWCNTs) and the chemically functionalized MWCNTs, by introducing polar groups such as carboxyl groups (-COOH) increasing their stability and dispersibility in the water media. As a starting point we evaluated the possible effects of the carboxylation/functionalization of the surface of MWCNTs in organisms for each exposure concentration. In all invertebrate species it was possible to observe a dose-dependent increased of the toxicity, especially in terms of oxidative status, which is in line with the information provided by the literature. Moreover, comparing the toxic effects of both CNTs, in all invertebrate species major cellular damage was induced by carboxylated forms of MWCNTs in comparison to the pristine one. Subsequently we selected the two most deleterious concentrations of Nf-MWCNTs and f-MWCNTs, and we exposed the three invertebrate species to the combination of CNT materials with salinity shifts and pH variations assessing if both climate change factors altered the toxicity of both MWCNT materials as well as the sensitivity of all these species exposed to these contaminates. The present findings underlined that Nf-MWCNTs and f-MWCNTs under control salinity and low pH generated major toxic impacts in the organisms compared to individuals maintained under low salinity and control pH, confirming that salinity shifts and pH variations may alter the chemical behaviour of both MWCNTs and consequent fate in exposed individuals. Moreover, we observed species-dependent sensitivity to contaminants confirming that the higher susceptibility observed in some species would however be expected not only to depend on the characteristics of the compounds, but also on the physiology of that particular species. For a better environment protection, the Ecological Risk Assessment of the mentioned stressors must include ecologically relevant endpoints and exposure scenarios to drive accurate safety levels towards biodiversity conservation.De acordo com publicações recentes, nos próximos 100 anos prevê-se um aumento na acidificação da água do mar e alterações na sua salinidade. Nas águas superficiais, o aumento do CO2 atmosférico já causou uma diminuição do pH em mais de 0,1 unidades comparando com 8,1, a média referente à época pré-industrial. Está previsto que até ao final deste século, esta redução do pH possa atingir valores na ordem das 0,13 e 0,43 unidades. As alterações climáticas podem também resultar em alterações na salinidade da água do mar. A salinidade é mais alta quando as temperaturas são mais altas e os períodos de chuva são reduzidos enquanto que, eventos de chuva intensa diminuem a salinidade da água do mar. Em qualquer dos cenários, estas alterações irão promover respostas por parte das espécies. Portanto, é imperativo identificar os efeitos das alterações climáticas nos ecossistemas aquáticos de modo a conservar a sua biodiversidade. Para além das alterações climáticas, há uma preocupação crescente com o grande número de poluentes emergentes que têm sido descartados no meio ambiente sem serem devidamente regulamentados. Entre estes poluentes emergentes estão as nanopartículas artificiais (Engineered nanoparticles - ENPs). Um dos tipos de ENPs mais usados nos últimos anos são os Nanotubos de Carbono (Carbon nanotubes - CNTs). Devido às suas propriedades químicas e nano-toxicológicas únicas, é expectável que os CNTs entrem nos ambientes aquáticos e se acumulem na fauna que lá vive. De facto, a toxicologia dos CNTs em sistemas aquáticos é complexa. Numa primeira análise, o tamanho, a forma, a estrutura química e os agentes de revestimento desempenharão um papel no que diz respeito à estabilidade e, portanto, à biodisponibilidade da partícula. No entanto, a toxicidade dos nano-materiais tem sido atribuída não só à sua estrutura central e modificação/funcionalização da sua superfície, mas também aos parâmetros físico-químicos do meio em que os nanotubos se apresentam e que podem alterar a sua dispersão e consequentemente a sua deteção: agregação/desagregação, adsorção/dessorção, sedimentação/ressuspensão e dissolução. O impacto dos nanotubos no meio aquático já foi descrito por vários autores; no entanto, ainda não se sabe de que forma as alterações climáticas podem alterar a toxicidade dos CNTs e subsequentemente os efeitos sobre os organismos marinhos. As espécies bentónicas são um bom modelo para avaliar os impactos das Alterações Climáticas e ENPs, uma vez que são sensíveis às mudanças ambientais. Principalmente devido às características do seu ciclo de vida, bem como à sua resposta relativamente rápida à poluição, há vários estudos que usam espécies bentónicas como bioindicadores para fatores de stress antropogénicos e naturais. Sendo assim, é urgente avaliar os impactos dos CNTs, sob alterações de salinidade e redução do pH em organismos aquáticos. Ruditapes philippinarum (bivalve), Hediste diversicolor e Diopatra neapolitana (poliquetas) são invertebrados marinhos que respondem rapidamente a perturbações ambientais e são caracterizados por uma ampla distribuição espacial e relevância económica, nomeadamente em Portugal. Pelo que, esta tese pretendeu avaliar os efeitos tóxicos de desvios de salinidade, variação de pH e presença de CNTs (atuando isolados ou em combinação) ao nível da resposta bioquímica (reservas de energia e atividade metabólica, estado oxidativo e neurotoxicidade) e da resposta fisiológica (capacidade regenerativa) das espécies acima citadas. Neste estudo, os dois materiais de CNT selecionados foram os nanotubos de carbono de parede múltipla, não funcionalizados (pristine multi walled carbon nanotubes - Nf-MWCNTs) e os MWCNTs quimicamente funcionalizados através da introdução de grupos polares como grupos carboxilo (-COOH), que aumentam sua estabilidade e capacidade de dispersão no meio aquoso. Como ponto de partida, para cada concentração de exposição, avaliamos os possíveis efeitos da carboxilação/funcionalização da superfície dos MWCNTs nos organismos. Em todas as espécies de invertebrados foi possível observar uma relação positiva entre o aumento da dose e a toxicidade, principalmente no que diz respeito ao estado oxidativo, o que está de acordo com a informação disponível na literatura. Além disso, comparando os efeitos tóxicos de ambos os CNTs, em todas as espécies de invertebrados, verificaram-se maior dano celular induzido pela forma carboxilada da MWCNT em comparação com a forma não funcionalizada. Posteriormente, selecionamos as duas concentrações de Nf-MWCNTs e f-MWCNTs mais perniciosas, e expusemos as três espécies de invertebrados à combinação destes materiais CNT com variações de salinidade e variações de pH, avaliando desta forma se estes fatores relacionados com as alterações climáticas modificavam a toxicidade de ambos os materiais MWCNT bem como a sensibilidade das espécies expostas a esses contaminantes. Os resultados obtidos salientam que Nf-MWCNTs e f-MWCNTs sob salinidade controlo e pH baixo, geraram grandes impactos tóxicos nos organismos em comparação com indivíduos mantidos em condições de salinidade baixa e pH controlo. Confirmou-se desta forma que, alterações de salinidade e variações de pH podem alterar o comportamento químico de ambos os MWCNTs e consequentemente o efeito em indivíduos expostos. Além disso, observamos que a sensibilidade ao contaminante é dependente da espécie o que confirma que a maior suscetibilidade observada em algumas espécies não é apenas um resultado das diferentes características dos compostos usados, mas também da fisiologia dessas espécies em particular. Para uma melhor proteção do meio ambiente, a Avaliação de Risco Ecológico dos fatores de stress mencionados, deve incluir objetivos e cenários de exposição ecologicamente relevantes para impulsionar medidas de segurança corretas e adaptadas com respeito à conservação da biodiversidade.Programa Doutoral em Biologia e Ecologia das Alterações Globai

Analytical and experimental FWHM of a gamma camera: theoretical and practical issues

It is well known that resolution on a gamma camera varies as a function of distance, scatter and the camera\u2019s characteristics (collimator type, crystal thickness, intrinsic resolution etc). Manufacturers frequently provide only a few pre-calculated resolution values (using a line source in air, 10\u201315 cm from the collimator surface and without scattering). However, these are typically not obtained in situations resembling a clinical setting. From a diagnostic point of view, it is useful to know the expected resolution of a gamma camera at a given distance from the collimator surface for a particular setting in order to decide whether it is worth scanning patients with \u201csmall lesion\u201d or not. When dealing with absolute quantification it is also mandatory to know precisely the expected resolution and its uncertainty in order to make appropriate corrections. Aim. Our aims are: to test a novel mathematical approach, the cubic spline interpolation, for the extraction of the full width at half maximum (FWHM) from the acquisition of a line source (experimental resolution) also considering measurement uncertainty; to compare it with the usually adopted methods such as the gaussian approach; to compare it with the theoretical resolution (analytical resolution) of a gamma camera at different distances; to create a web-based educational program with which to test these theories. Methods. Three mathematical methods (direct calculation, global interpolation using gaussian and local interpolation using splines) for calculatingFWHMfroma line source (planar scintigraphy) were tested and compared. A NEMA Triple Line Source Phantom was used to obtain static images both in air and with different scattering levels. An advanced, open-source software (MATLAB/Octave and PHP based) was created \u201cad hoc\u201d to obtain and compareFWHMvalues and relative uncertainty. Results and Conclusion. Local interpolation using splines proved faster and more reliable than the usually-adopted Gaussian interpolation. The proposed freely available software proved effective in assessing bothFWHMand its uncertainty

Pazopanib, un inibitore tirosin-chinasico nel trattamento del sarcoma dei tessuti molli ed in altri trattamenti terapeutici

Le proteine chinasi rappresentano un importante target terapeutico in quanto sono coinvolte nella crescita, nella differenziazione, nel metabolismo e nella morte cellulare. Il livello di attività delle proteine tirosin-chinasiche aumenta di circa 10-20 volte nelle cellule tumorali. I recettori che hanno avuto una maggior attenzione sono quelli della famiglia dell'EGF, per la loro frequente iperespressione nei tumori epiteliali, e i recettori della famiglia del VEGF, responsabili della neo-angiogenesi tumorale. Pazopanib è un inibitore di diversi recettori tirosin-chinasici attraverso i quali svolge un'azione antiangiogenica e antitumorale. Pazopanib è un farmaco antitumorale indicato nel trattamento di prima linea del carcinoma a cellule renali (RCC) avanzato e nel trattamento dei pazienti adulti affetti da alcune forme di sarcoma dei tessuti molli (STS) in stato avanzato che hanno ricevuto in precedenza chemioterapia per malattia metastatica o che sono andati in progressione entro 12 mesi dopo la terapia neoadiuvante. Inoltre l'attività di Pazopanib in gocce oculari è stata confrontata con quella di Ranibizumab nei soggetti con neovascolarizzazione coroidale (CNV) provocata dalla degenerazione maculare legata all'età (AMD). Inifine, gli inibitori tirosin-chinasici, tra cui anche Pazopanib, sembrano essere agenti promettenti per la terapia sistemica nei pazienti con tumore tiroideo

LabCity. Un laboratorio creativo sulla cittadinanza per dare voce ai Minori Stranieri Non Accompagnati

Ai fini della ricerca sul campo per la tesi di Dottorato, è stato progettato un laboratorio creativo sulla cittadinanza, suddiviso in tre giornate, in cui i Minori Stranieri Non Accompagnati si sono confrontati sul tale tema sia in sensolegislativo, sia in senso di cittadinanza attiva, con tecniche didattiche e attivitàvarie. I ragazzi con la partecipazione alle discussioni e con i loro lavori, hanno espresso la loro idea di futuro sia come persone, sia come cittadini. Qui si riporta in sintesi dei risultati ottenuti dall’analisi dei dati di questo laboratorio

Kardiovaskuläre hämodynamische Veränderungen nach antenatalenKortikosteroiden bei Feten mit intrauteriner Wachstumsretar-dierung und bei zeitgerecht entwickelten Feten

PURPOSE:  To investigate hemodynamic effects after antenatal corticosteroids (ACS) administration in appropriate for gestational age (AGA) and early growth restricted (GR) fetuses by measurement of Doppler cardiovascular function parameters. MATERIALS AND METHODS:  Prospective cohort study. AGA and GR singleton pregnancies receiving ACS for fetal lung maturation between 24 + 0 - 33 + 6 weeks were enrolled. Feto-placental vascular hemodynamics were studied by: umbilical artery (UA) pulsatility index (PI), middle cerebral artery (MCA) PI, renal artery (RenA) PI. Cardiac function was evaluated by ductus venosus (DV) PI and by echocardiographic parameters: E to A wave ratios (E/A) and mitral and tricuspid annular plane systolic excursion (MAPSE and TAPSE) for diastolic function, left and right myocardial performance index (MPI) for overall (diastolic and systolic) function. A single operator performed all the measurements at 3 different time points (E): E0 before or within 4 hours of ACS administration (baseline examination), E1 24 - 48 hours after the first dose and E2 7 days after the second dose of ACS. The values were expressed as z-scores. Pairwise comparisons with paired t-test were performed to compare measurements before and after exposure to ACS. RESULTS:  25 AGA and 20 GR fetuses (mean gestational age: 31 + 1 and 30 + 6, respectively) were included in the analysis. In the AGA group ACS administration was associated with a significant reduction in UA PI. In the GR fetuses ACS temporarily (E0-E1) restored UA-end diastolic flow (EDF) in 6 of 9 fetuses with A/R-EDF ("Return of EDF phenomenon") and produced a significant increase (worsening) in right MPI (both in E1-E2 and in E0-E2). CONCLUSION:  ACS administration is associated with UA vasodilation in both AGA and GR fetuses and with an increase in right MPI in the latter group. This suggests a worsening in cardiac function in GR fetuses

Quercetin can act either as an inhibitor or an inducer of the mitochondrial permeability transition pore: A demonstration of the ambivalent redox character of polyphenols

AbstractThe Ca2+- and oxidative stress-induced mitochondrial permeability transition (MPT) plays an important role in phenomena ranging from tissue damage upon infarction to muscle wasting in some forms of dystrophy. The process is due to the activation of a large pore in the inner mitochondrial membrane. Anti-oxidants are considered a preventive and remedial tool, and mitochondria-targeted redox-active compounds have been developed. Plant polyphenols are generally considered as anti-oxidants, and thus candidates to the role of mitochondria-protecting agents. In patch-clamp experiments, easily oxidizable polyphenols induced closure of the MPT channel. In swelling experiments with suspensions of mitochondria, high (20–50 μM) concentrations of quercetin, the most efficient inhibitor, promoted instead the onset of the MPT. Chelators of Fe2+/3+ and Cu+/2+ ions counteracted this effect. Fluorescent indicators of superoxide production confirmed that quercetin potentiates O2− generation by isolated mitochondria and cultured cells. Since this was not affected by chelating Fe and Cu ions, the MPT-inducing effect can be ascribed to a “secondary”, metal ion-catalyzed production of ROS. These results are a direct demonstration of the ambivalent redox character of polyphenols. Their mode of action in vivo cannot be taken for granted, but needs to be experimentally verified

Determining Noise and Vibration Exposure in Conifer Cross-Cutting Operations by Using Li-Ion Batteries and Electric Chainsaws

In many activities, chainsaw users are exposed to the risk of injuries and several other hazard factors that may cause health problems. In fact, environmental and working conditions when using chainsaws result in workers’ exposure to hazards such as noise, vibration, exhaust gases, and wood dust. Repeated or continuous exposure to these unfavourable conditions can lead to occupational diseases that become apparent after a certain period of time has elapsed. Since the use of electric tools is increasing in forestry, the present research aims to evaluate the noise and vibration exposure caused by four models of electric chainsaws (Stihl MSA160T, Stihl MSA200C Li-Ion battery powered and Stihl MSE180C, Stihl MSE220C wired) during cross-cutting. Values measured on the Stihl MSA160T chainsaw (Li-Ion battery) showed similar vibration levels on both right and left handles (0.9–1.0 m s−2, respectively) and so did the other battery-powered chainsaw, the Stihl MSA200C (2.2–2.3 m s−2 for right and left handles, respectively). Results showed a range of noise included between 81 and 90 dB(A) for the analysed chainsaws. In conclusion, the vibrations and noise were lower for the battery chainsaws than the wired ones, but, in general, all the values were lower than those measured in previous studies of endothermic chainsaws

How safe are the new green energy resources for marine wildlife? The case of lithium

Considering the increasing use of Lithium (Li) and the necessity to fulfil this demand, labile Li occurrence in the environment will be enhanced. Thus, additional research is needed regarding the presence of this element in marine environment and its potential toxic impacts towards inhabiting wildlife. The aim of the present study was to evaluate Li toxicity based on the exposure of Mytilus galloprovincialis to this metal, assessing the biochemical changes related with mussels' metabolism, oxidative stress and neurotoxicity. For this, organisms were exposed to different Li concentrations (100, 250, 750 μg/L) for 28 days. The results obtained clearly demonstrated that Li lead to mussels' metabolism depression. The present study also revealed that, especially at the highest concentrations, antioxidant and biotransformation enzymes were not activated, leading to the occurrence of lipid peroxidation and loss of redox homeostasis, with increased content in oxidized glutathione in comparison to the reduced form. Furthermore, after 28 days, higher Li exposure concentrations induced neurotoxic effects in mussels, with a decrease in acetylcholinesterase enzyme activity. The responses observed were closely related with Li concentrations in mussels' tissues, which were more pronounced at higher exposure concentrations. Such results highlight the potential toxic effects of Li to marine species, which may even be higher under predicted climate changes and/or in the presence of other pollutants.publishe

A Comparison between the Latest Models of Li-Ion Batteries and Petrol Chainsaws Assessing Noise and Vibration Exposure in Cross-Cutting

Chainsaw operators are exposed to many hazards that can lead to health problems. The two most frequently documented ergonomics threats in the use of chainsaws are noise and vibration exposure. Since the use of battery chainsaws is increasing due to the growing improvements in battery life and power, the study aims to compare the difference in terms of noise emission and vibration levels of the following two new models of chainsaws: the battery-powered Stihl MSA 300 and the petrol-powered Stihl MS 261 C-M. Black pine and European beech logs were cross-cut in order to evaluate both noise and vibration exposure. The results show that the use of battery-powered chainsaws, in comparison to the petrol one, can reduce the daily vibration exposure by more than 51% and the noise dose by 11%. The daily vibration exposure of 1.60 ms−2 and 1.67 ms−2 measured for the battery-powered chainsaw on Black pine and on European beech, respectively, is far from the daily exposure action value set by the EU directives for health and safety requirements (2.5 ms−2). On the contrary, the daily noise exposure for the battery chainsaw was 93 dB(A), exceeding the upper exposure action value of 85 dB(A)