216 research outputs found
Lead and Zinc contamination of surface sediments in the main harbours of the Galician Rias
The concentration ranges and degree of contamination of lead and zinc in the four principal harbour areas of the northwest Iberian Peninsula have been defined from 130 surface sediment samples (A partir de la fracción fina en 130 muestras de sedimento superficial se han cuantificado los niveles de concentración para plomo y cinc en las rías donde se encuentran los principales puertos de la costa gallega. Los patrones de distribución de Pb y Zn en el sedimento muestran altos contenidos en el litoral próximo a las áreas de actividad portuaria y astilleros: las concentraciones llegan hasta 140, 160, 160 y 320 mg·kg-1 para Pb y hasta 150, 380, 600 y 1960 mg·kg-1 para Zn en Pontevedra, Coruña, Ferrol y Vigo, respectivamente. En base a sus niveles naturales, establecidos mediante cuatro testigos de sedimento, se han definido sus grados de contaminación mediante factores de enriquecimiento. Consecuentemente, se puede definir entre moderada y considerable la contaminación de Pb y Zn en los puertos de La Coruña y Pontevedra, así como severa en Ferrol y Vigo. En otras zonas de las rías la contaminación normalmente decrece, como suele ocurrir en estuarios y costas de nuestro planeta donde existen puertos o astilleros
Chitosan encapsulation modulates the effect of capsaicin on the tight junctions of MDCK cells
Capsaicin has known pharmacological effects including the ability to reversibly open cellular tight junctions, among others. The aim of this study was to develop a strategy to enhance the paracellular transport of a substance with low permeability (FITC-dextran) across an epithelial cell monolayer via reversible opening of cellular tight junctions using a nanosystem comprised by capsaicin and of chitosan. We compared the biophysical properties of free capsaicin and capsaicin-loaded chitosan nanocapsules, including their cytotoxicity towards epithelial MDCK-C7 cells and their effect on the integrity of tight junctions, membrane permeability and cellular uptake. The cytotoxic response of MDCK-C7 cells to capsaicin at a concentration of 500 μM, which was evident for the free compound, is not observable following its encapsulation. The interaction between nanocapsules and the tight junctions of MDCK-C7 cells was investigated by impedance spectroscopy, digital holographic microscopy and structured illumination fluorescence microscopy. The nanocapsules modulated the interaction between capsaicin and tight junctions as shown by the different time profile of trans-epithelial electrical resistance and the enhanced permeability of monolayers incubated with FITC-dextran. Structured illumination fluorescence microscopy showed that the nanocapsules were internalized by MDCK-C7 cells. The capsaicin-loaded nanocapsules could be further developed as drug nanocarriers with enhanced epithelial permeability
Cadmium, manganese, nickel and lead contents in surface sediments of the lower Ulla River and its estuary (northwest Spain)
The authors determined the total contents of cadmium, manganese, nickel and lead in 16 surface sediment samples along the last 7 km of the Ulla River and in its estuary. Prior to chemical analysis, the grain-size fractions below 500, 63 and 2 μm were separated. The metal concentrations were analysed in the fraction below 63 μm, and in selected samples from the clay fraction ( 2 μm). The soil samples were digested with a HF + HNO₃ + HCl mixture and the total concentrations of Cd, Mn, Ni and Pb were analysed with the AAS method. The highest contents of metals were found in the riverine sediments, near the town of Padrón, and in the estuary. The enrichment of metals in the sediments was mainly related to the proximity of the industrial sources, and to the fine particles transported and deposited in the sediments. The Ni and Mn contents found are considered very high, at some points reaching values of up to 357 mg kg⁻¹ and 2 110 mg kg⁻¹, respectively. Lead and Cd were mainly found within the range considered as natural background levels in the sediments of the Galician rias, with concentrations of 25-68 mg kg⁻¹ for Pb and 0.01-0.92 mg kg⁻¹ for Cd. The lower part of the Ulla River and its estuary present: l) moderate to high contamination levels of Mn and Ni; 2) moderate Pb pollution levels; and 3) no Cd contamination. The highest concentrations of metals were obtained in the river, near the wastewater discharges, and in the estuary, associated with fine particles.El contenido total de cadmio, manganeso, níquel y plomo se determinó en 16 muestras de sedimentos superficiales a lo largo de los últimos 7 km del río Ulla y en su estuario. Previamente a los análisis químicos, se realizó la separación granulométrica de los sedimentos en las fracciones inferiores a 500, 63 y 2 μm. La concentración de metales se determinó en la fracción inferior a 63 μm y, para algunas muestras, en la fracción arcilla ( 2 μm). La digestión del sedimento se realizó en una mezcla ácida de HF + HNO₃ + HCl y se analizó la concentración total de Cd, Mn, Ni y Pb por espectroscopia de absorción atómica. Los contenidos más altos en metales se encontraron en los sedimentos del río, en las inmediaciones de Padrón y en los del estuario. El enriquecimiento de los sedimentos en metales se ha relacionado con la proximidad a las zonas industriales y con el material fino transportado y depositado en los sedimentos. Se han encontrado contenidos muy altos de Ni y Mn con valores de 357 mg kg⁻¹ y 2 110 mg kg⁻¹, respectivamente. Las concentraciones de Cd y Pb son comparables a los valores establecidos como niveles naturales en los sedimentos de las rías gallegas: 25-68 mg kg⁻¹ para el Pb y 0.01-0.92 mg kg⁻¹ para el Cd. El sedimento de la parte baja del río Ulla y su estuario presentan niveles moderados-altos de contaminación para Mn y Ni, moderados para Pb y nulos para Cd. Las mayores concentraciones de estos metales en el sedimento fueron medidas asociadas con las fracciones finas ( 63 μm): cerca de Padrón, zona de influencia fluvial y, también, aunque con valores más bajos, en la desembocadura del Ulla, zona de influencia marina.Instituto Español de Oceanografí
The national inventory of geological heritage: methodological approach and results
A existência de um inventário nacional de património geológico é fundamental para se poderem implementar estratégias de geoconservação. Este trabalho apresenta a metodologia usada no desenvolvimento do mais completo inventário de geossítios, realizado até ao momento em Portugal, assim como os principais resultados obtidos. O inventário vai integrar o Sistema de Informação do Património Natural e o Cadastro Nacional dos Valores Naturais Classificados, ambos geridos pelo Instituto de Conservação da Natureza e da Biodiversidade.The existence of a national inventory of the geological heritage is of paramount importance for the implementation of a geoconservation strategy. This paper presents the methodological approach used to produce the most complete geosites inventory in Portugal, so far, and the obtained results. This inventory will be uploaded into the National Database of Natural Heritage managed by the Portuguese authority for nature conservation.Este trabalho é apoiado pela Fundação para a Ciência e a Tecnologia, através do financiamento plurianual do CGUP e do projecto de investigação “Identificação, caracterização e conservação do património geológico: uma estratégia de geoconservação para Portugal” (PTDC/CTE-GEX/64966/2006).info:eu-repo/semantics/publishedVersio
Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).
Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)
Embolia arterial por proyectil de arma de fuego: Comunicación de un caso y revisión de la literatura
A case is presented of a patient with a bu/Jet injury in theleft hemithorax whose projectile embolized and impactsin the popliteal artery determining accute arterialocclusion of the /eft /ower /imb. Epidemiological,pathogenical, diagnostica/ and therapeuticalconsiderations are made as regards arterial and venousembolia due to fire-arm projectiles and bibliography onthis rare complication of bu/Jet injuries is revised.Se presenta el caso de un paciente con herida de balaen hemitórax izquierdo cuyo proyectil se emboliza eimpacta en la arteria poplítea determinando una oclusiónarterial aguda de miembro inferior izquierdo. Se realizanconsideraciones epidemiológicas, pa togéncase is presented of a patient with a bu/Jet injury in theleft hemithorax whose projectile embolized and impactsin the popliteal artery determining accute arterialocclusion of the /eft /ower /imb. Epidemiological,pathogenical, diagnostica/ and therapeuticalconsiderations are made as regards arterial and venousembolia due to fire-arm projectiles and bibliography onthis rare complication of bu/Jet injuries is revised.??]<icas,diagnósticas y terapéuticas sobre las embolias arterialesy venosas de los proyectiles de arma de fuego y serevisa la literatura acerca de esta rara complicación delos heridos de bala
Edible bio-based nanostructures: delivery, absorption and potential toxicity
The development of bio-based nanostructures as nanocarriers of bioactive compounds to specific body sites has been presented as a hot topic in food, pharmaceutical and nanotechnology fields. Food and pharmaceutical industries seek to explore the huge potential of these nanostructures, once they can be entirely composed of biocompatible and non-toxic materials. At the same time, they allow the incorporation of lipophilic and hydrophilic bioactive compounds protecting them against degradation, maintaining its active and functional performance. Nevertheless, the physicochemical properties of such structures (e.g., size and charge) could change significantly their behavior in the gastrointestinal (GI) tract. The main challenges in the development of these nanostructures are the proper characterization and understanding of the processes occurring at their surface, when in contact with living systems. This is crucial to understand their delivery and absorption behavior as well as to recognize potential toxicological effects. This review will provide an insight into the recent innovations and challenges in the field of delivery via GI tract using bio-based nanostructures. Also, an overview of the approaches followed to ensure an effective deliver (e.g., avoiding physiological barriers) and to enhance stability and absorptive intestinal uptake of bioactive compounds will be provided. Information about nanostructures potential toxicity and a concise description of the in vitro and in vivo toxicity studies will also be given.Joana T. Martins, Oscar L. Ramos, Ana C. Pinheiro, Ana I. Bourbon, Helder D. Silva and Miguel A. Cerqueira (SFRH/BPD/89992/2012, SFRH/BPD/80766/2011, SFRH/BPD/101181/2014, SFRH/BD/73178/2010, SFRH/BD/81288/2011, and SFRH/BPD/72753/2010, respectively) are the recipients of a fellowship from the Fundacao para a Ciencia e Tecnologia (FCT, POPH-QREN and FSE, Portugal). The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013 and the project "BioInd-Biotechnology and Bioengineering for improved Industrial and Agro-Food processes," REF.NORTE-07-0124-FEDER-000028, co-funded by the Programa Operacional Regional do Norte (ON.2-O Novo Norte), QREN, FEDER. We also thank to the European Commission: BIOCAPS (316265, FP7/REGPOT-2012-2013.1) and Xunta de Galicia: Agrupamento INBIOMED (2012/273) and Grupo con potencial de crecimiento. The support of EU Cost Action FA1001 is gratefully acknowledged
Evolución histórica de la prótesis de cadera
Nadie duda ya de la enorme importancia que supuso la artroplastia de cadera en el progreso médico, pues no sólo avanzó el campo de la cirugía ortopédica, sino también la calidad de vida de la población susceptible de la misma. El paso de los años supuso tanto el avance de las características técnicas de la artroplastia de cadera (aspectos biomecánicos, materiales empleados...) como la adecuación cada vez mayor de los diferentes tipos de prótesis a las peculiaridades y necesidades de los pacientes.
A lo largo de este artículo nuestra intención es ofrecer una visión histórica del desarrollo operado en el campo de las prótesis de cadera, evolución que ha permitido, por un lado, la reconstrucción de caderas muy discapacitantes y, por otro, adecuar cada vez más el binomio prótesis-pacientes.Nobody already doubts of the enormous importance that supposed the hip arthroplasty in the medica! progress, because the field of the orthopedic surgery didn't only advance, but also the quality of the susceptible populations of the same one lile. The step of the years supposed the advance of the technical characteristics of the hip arthroplasty so much (biomechanicals aspects, materials used ... ), as the adaptation every time bigger than the different prosthesis types to the peculiarities and the patients necessities.
Along our article intention it is the one of offering a historical vision of the development operated in the field of the hip prosthesis, evolution that has allowed, on one hand, the reconstruction of hips very discapacitantes and, for other, to adapt more and more the binomial prosthesis-patient
Volcanism and climate change as drivers in Holocene depositional dynamic of Laguna del Maule (Andes of central Chile – 36° S)
Late Quaternary volcanic basins are active landscapes from which detailed archives of past climate and seismic and volcanic activity can be obtained. A multidisciplinary study performed on a transect of sediment cores was used to reconstruct the depositional evolution of the high-elevation Laguna del Maule (LdM) (36∘ S, 2180 m a.s.l., Chilean Andes). The recovered 5 m composite sediment sequence includes two thick turbidite units (LT1 and LT2) and numerous tephra layers (23 ash and 6 lapilli). We produced an age model based on nine new 14C AMS dates, existing 210Pb and 137Cs data, and the Quizapú ash horizon (1932 CE). According to this age model, the relatively drier Early Holocene was followed by a phase of increased productivity during the mid-Holocene and higher lake levels after 4.0 ka cal BP. Major hydroclimate transitions occurred at ca. 11, 8.0, 4.0 and 0.5 ka cal BP. Decreased summer insolation and winter precipitation due to a southward shift in the southern westerly winds and a strengthened Pacific Subtropical High could explain Early Holocene lower lake levels. Increased biological productivity during the mid-Holocene (∼8.0 to 6.0 ka cal BP) is coeval with a warm–dry phase described for much of southern South America. Periods of higher lake productivity are synchronous to a higher frequency of volcanic events. During the Late Holocene, the tephra layers show compositional changes suggesting a transition from silica-rich to silica-poor magmas at around 4.0 ka cal BP. This transition was synchronous with increased variability of sedimentary facies and geochemical proxies, indicating higher lake levels and increased moisture at LdM after 4.0 ka cal BP, most likely caused by the inception of current El Niño–Southern Oscillation and Pacific Decadal Oscillation (ENSO–PDO) dynamics in central Chile.Postprin
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