794 research outputs found

    Theranostics Through the Synergistic Cooperation of Heterometallic Complexes

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    Heterometallic drugs are emerging as a great alternative to conventional metallodrugs. Careful selection of different metallic fragments makes possible to enhance not only the therapeutic potential by a synergistic effect, but also to incorpore key features like traceability. Drugs that integrate traceability and therapy in one system are known as theranostic agents. In cancer research, theranostic agents are becoming increasingly important. They deliver crucial information regarding their biological interplay that can ultimately be used for optimization. The well-established therapeutic potential of PtII-, RuII- and AuI-based drugs combined with the outstanding optical properties of d6 transition metal complexes grant the delivery of traceable metallodrugs. These species can be easily fine-tuned through modification of their respective ligands to provide a new generation of drugs

    Luminescent Re(I)/Au(I) Species As Selective Anticancer Agents for HeLa Cells

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    A series of neutral and cationic heterotrimetallic complexes of the type fac-[Re(CO)3(bipy(CC)2-(AuL)2)X]n, where bipy(CC)2 is 4, 4'-alkynyl-2, 2'-bipyridine; L is either triphenylphosphine (PPh3), [1, 3-bis(2, 6-diisopropylphenyl)-imidazol-2-ylidene] (IPr), or tert-butyl isocyanide (CNtBu); and X is a chloride (n = 0) or acetonitrile (n = 1), were synthesized and characterized together with their Re(I) precursors, i.e., fac-[Re(CO)3(bipy(CC)2)X]n. X-ray diffraction of complexes 1, 3, and 6 corroborated the expected octahedral and linear distribution of the ligands along the Re(I) and Au(I) centers, respectively. Luminescent studies showed that all the complexes displayed a broad emission band centered between 565 and 680 nm, corresponding to a 3MLCT from the Re(I) to the diimine derivative. The presence of the gold fragment coordinated to the diimine ligand shifted in all cases the emission maxima toward higher energies. Such an emission difference could be potentially used for assessing the precise moment of interaction of the probe with the biological target if the gold fragment is implicated. Antiproliferative studies in cancer cells, A549 (lung cancer) and HeLa (cervix cancer), showed a generalized selectivity toward HeLa cells for those heterotrimetallic species incubated at longer times (72 vs 24 h). ICP-MS spectrometry revealed the greater cell internalization of cationic vs neutral species. Preliminary fluorescence microscopy experiments showed a different behavior of the complexes in HeLa and A549 cell lines. Whereas the complexes in A549 were randomly distributed in the outside of the cell, those incubated with HeLa cells were located close to the cellular membrane, suggesting some type of interaction, and possibly explaining their cellular selectivity when it comes to the antiproliferative activity displayed in the different cell lines

    Studies on the association of the Quercus suber decline disease with Phytophthora cinnamomi in Portugal

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    En Portugal, la enfermedad de la “seca” se ha descrito en los Quercus de hoja perenne (Quercus suber L. and Q.ilex subsp. rotundifolia Lam.) desde el final del siglo XIX. La mortalidad de estas especies afecta, particularmente las regiones centrales y meridionales del país, siendo uno de los problemas forestales más graves. Phytophthora cinnamomi Rands es el principal patógeno responsable de la mortalidad de alcornoques y encinas en Portugal. Se han desarrollado varios estudios teniendo como objetivo una mejor comprensión del efecto de la acción de P. cinnamomi en el decaimiento de los Quercus. El actual trabajo describe resultados preliminares de algunos de estos estudios.___________________________________In Portugal, the decline disease has been described in evergreen oaks (Quercus suber L. and Q.ilex subsp. rotundifolia Lam.) since the end of the 19th century. The mortality of these species affects, particularly the central and southern regions of the country, being one of the most severe forest problems. Phytophthora cinnamomi Rands is the main pathogen responsible for the cork and holm oak mortality in Portugal. Several studies have been developed aiming at a better understanding of the effect of the P. cinnamomi action on the cork oak trees decline. The present work describes preliminary results of some of these studies

    Respiratory evaluation through volumetric capnography among grade III obese and eutrophic individuals: a comparative study

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    sem informaçãoExcess trunk body fat in obese individuals influences respiratory physiological function. The of this study were to compare volumetric capnography findings (VCap) between severely obese patients and normal-weight subjects and to assess whether there is a1372177183sem informaçãosem informaçãosem informaçã

    A path-flow analysis model for active drag force determinant variables in age-group swimmers

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    The goal of competitive swimming is to travel the event distance as fast as possible. The identification of the parameters that predict swimming performances is one of the main aims of the swimming “science” community. Indeed, it is consensual that biomechanical and energetic variables are determinant for enhance performance (Barbosa et al, 2010)

    Gold Thione Complexes

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    The reaction of the ligand Et4todit (4,5,6,7-Tetrathiocino-[1,2-b:3,4-b']-diimidazolyl-1,3,8,10-tetraethyl-2,9-dithione) with gold complexes leads to the dinuclear gold(I) complexes [{Au(C6F5)}2(Et4todit)] and [Au(Et4todit)]2(OTf)2, which do not contain any gold-gold interactions, or to the gold(III) derivative [{Au(C6F5)3}2(Et4todit)]. The cristal structures have been established by X-ray diffraction studies and show that the gold centers coordinate to the sulfur atoms of the imidazoline-2-thione groups

    O depósito de Sn-Li associado a granito de grande tonelagem da Argemela, Portugal central

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    The Argemela Sn-Li quartz vein stockwork, east of the Panasqueira tungsten mine, is hosted in Cambrian slates and greywacke. An underlying Variscan granitic cupola is inferred from spotted slates and albitic microgranite dykes, the last including a thick modified albitic microgranite, enriched in F and Li, exposed some 500 m away, on the hill top. Inferred resources for shallowest deposit portion are 20.1 million tonnes (Mt) at 0.1-0.2% Sn, 0.2% Li and 0.1% (estimate) Rb, but the 650-m vertical-extent of the deposit suggests a resource of >200 Mt (with identical grades). The hydrothermal paragenetic sequence is amblygonite-montebrasite (mostly montebrasite) (Stage I)–quartz I-II–cassiterite (with columbite-tantalite inclusions)─arsenopyrite I─carbonate I-white mica I ─chlorite I–fluorite–apatite–rutile (Stage II)– white mica II–molybdenite– tourmaline– carbonate II-quartz III–arsenopyrite II–sphalerite–stannite–chalcopyrite–pyrite– pyrrhotite-chlorite II (Stage III)–covellite– vivianite–goethite/lepidocrocite (Stage IV). Amblygonite-montebrasite is the main Li carrier; Sn is evenly distributed between cassiterite and stannite; Rb is mostly in white mica (with 0.25-1.23 wt % Rb2O in the hill-top albitic microgranite). Primary aqueous, 1-3 um-wide fluid inclusions in the deposit in quartz I, carbonate I, apatite and cassiterite growth zones yield overall salinities and homogenisation temperatures of 7.2-19.1 wt % NaCl equiv. and 290-360ºC, respectively. The trace concentrations (electronic microprobe analysis) in quartz vein cassiterite reach 1.95 wt % Nb, 0.39 wt % Fe, 0.13 wt % Ti, and low/negligible values of Sb, Zn, As, Ag and Bi showing its granite-hydrothermal affiliation. Fe-poor and Fe-rich sphalerite (lower-intermediate and upper deposit parts) contain 1.0-1.6 and 7.9-9.4 wt % Fe, 64.3-66.0 and 55.9-57.2 wt % Zn, 0.4-0.5 and 0.9-1.1 wt % Cd, respectively. The sphalerite-stannite geothermometer yields temperatures of 245-297ºC. Following higher temperature amblygonite-montebrasite deposition (Stage I), hydrothermal fluids (aCl-=0.25 m), related to the hidden granitic cupola, at a mean pressure-corrected (50 MPa) temperature of 350ºC, were responsible for Stage II minerals deposition. Calculated cassiterite deposition from Sn chloride complexes occurred likewise, from probable magmatic-hydrothermal fluids, at fO2 = 10-34 -10-32 atm and pH=3.5-4. Cassiterite deposition mechanisms were oxidation, mixing, neutralisation, possible aCl- increase, and cooling. Later Fe-poor sphalerite (+kesterite/ferrokesterite) and Fe-rich sphalerite (+stannite) deposited at higher and lower fS2, respectively, the latter probably at a higher fO2 (Stage III). The uniqueness of Argemela system with abundant amblygonite-montebrasite in hydrothermal quartz tin veins may be related to an extreme fractionated F-, Li- and P-rich granitic magma. After the emplacement of the granite/albitic microgranite dykes, an emerging pegmatitic fluid was unable, possibly due to insufficient depth, to form pegmatites but only modified the hill-top albitic microgranite. As a consequence, the system, where mixing of high- and low-salinity magmatic fluids probably occurred, remained very enriched in F, Li and P and by the time the hydrothermal stockwork developed amblygonite-montebrasite (Stage I) was the first mineral to deposit abundantly before Stage II minerals deposition in those Argemela Sn-Li quartz veins.El filón de cuarzo Sn-Li de Argemela, al este de la mina de wolframio de Panasqueira, está alojado en pizarras y gravas del Cámbrico. Se infiere una cúpula granítica subyacente del Varisco a partir de pizarras moteadas y diques de microgranito albítico, este último incluye un grueso microgranito albítico modificado, enriquecido en F y Li, expuesto a unos 500 m, en la cima de la colina. Los recursos inferidos para la parte más superficial del yacimiento son de 20,1 millones de toneladas (Mt) con 0,1-0,2% de Sn, 0,2% de Li y 0,1% (estimado) de Rb, pero la extensión vertical de 650 m del yacimiento sugiere un recurso de >200 Mt (con idénticas calidades). La secuencia paragénica hidrotermal es ambligonita-montebrasita (mayoritariamente montebrasita) (etapa I)-cuarzo I-II-casiterita (con inclusiones de columbita-tantalita)─arsenopirita I─carbonato I- mica blanca I ─clorita I-fluorita-apatita-rutilo (Estadio II)-mica blanca II-molibdenita-turmalina-carbonato II-cuarzo III-arsenopirita II-esfalerita-estanita-calcopirita-pirrotita-clorita II (Estadio III)-covellita-vivianita-goethita/lepidocrocita (Estadio IV). La ambligonita-montebrasita es el principal portador de Li; el Sn está distribuido uniformemente entre la casiterita y la estannita; el Rb se encuentra mayoritariamente en la mica blanca (con 0,25-1,23 % en peso de Rb2O en el microgranito albítico de la cima). Las inclusiones fluidas primarias acuosas de 1-3 um de ancho en el yacimiento en las zonas de crecimiento de cuarzo I, carbonato I, apatito y casiterita arrojan salinidades globales y temperaturas de homogeneización de 7,2-19,1 wt % de NaCl equiv. y 290-360ºC, respectivamente. Las concentraciones de trazas (análisis por microsonda electrónica) en la casiterita de las vetas de cuarzo alcanzan el 1,95 % en peso de Nb, el 0,39 % en peso de Fe, el 0,13 % en peso de Ti, y valores bajos/negligibles de Sb, Zn, As, Ag y Bi, lo que demuestra su filiación granítica-hidrotermal. La esfalerita pobre en Fe y rica en Fe (partes inferior-intermedia y superior del yacimiento) contienen 1,0-1,6 y 7,9-9,4 % en peso de Fe, 64,3-66,0 y 55,9-57,2 % en peso de Zn, 0,4-0,5 y 0,9-1,1 % en peso de Cd, respectivamente. El geotermómetro de esfalerita-estanita arroja temperaturas de 245-297ºC. Tras la deposición de ambligonita-montebrasita a mayor temperatura (Etapa I), los fluidos hidrotermales (aCl-=0,25 m), relacionados con la cúpula granítica oculta, a una temperatura media corregida por presión (50 MPa) de 350ºC, fueron los responsables de la deposición de minerales de la Etapa II. La deposición de casiterita calculada a partir de complejos de cloruro de Sn se produjo igualmente, a partir de probables fluidos magmáticos-hidrotermales, a fO2 = 10-34 -10-32 atm y pH=3,5-4. Los mecanismos de deposición de casiterita fueron la oxidación, la mezcla, la neutralización, el posible aumento de aCl- y el enfriamiento. Más tarde, la esfalerita pobre en Fe (+kesterita/ferrokesterita) y la esfalerita rica en Fe (+estanita) se depositaron a una fS2 más alta y más baja, respectivamente, esta última probablemente a una fO2 más alta (estadio III). La singularidad del sistema de Argemela, con abundante ambligonita-montebrasita en las vetas hidrotermales de cuarzo-estaño, puede estar relacionada con un magma granítico extremadamente rico en F, Li y P. Tras el emplazamiento de los diques de granito/microgranito albítico, un fluido pegmatítico emergente fue incapaz, posiblemente debido a la insuficiente profundidad, de formar pegmatitas, sino que sólo modificó el microgranito albítico de la cima. Como consecuencia, el sistema, en el que probablemente se produjo la mezcla de fluidos magmáticos de alta y baja salinidad, permaneció muy enriquecido en F, Li y P y, en el momento en que se desarrolló el stockwork hidrotermal, la ambligonita-montebrasita (Etapa I) fue el primer mineral que se depositó abundantemente antes de la deposición de los minerales de la Etapa II en esas vetas de cuarzo con Sn-Li de Argemela

    Variability in young swimmer’ performance and its determinant factors: a two-year follow-up

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    Predicting sports performance and identifying talented athletes at early ages seems to be a challenging task for practioners and researchers. Based on this, the follow-up of individual pathway to exper?se should be a regular procedure among sports practioners.info:eu-repo/semantics/publishedVersio

    Luminescent gold-thallium derivatives with a pyridine-containing 12-membered aza-thioether macrocycle

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    The coordination modes of the ligand 2, 5, 8-trithia[9](2, 6)pyridinophane (L) to thallium(i), gold(iii) and gold(i) have been studied. Thallium(i) is coordinated by the macrocyclic ligand in [Tl(L)](PF6) (1) through all the sulfur and nitrogen atoms, in a distorted square-pyramidal geometry with the thallium(i) ion in the apical position and with the presence of an inert lone pair. Gold(iii) is bonded by the ligand only through the nitrogen of the pyridine group in [AuCl3(L)] (2), whereas two AuI-C6F5fragments coordinate the sulfur atoms next to the pyridine moiety of the ligand in [{Au(C6F5)}2(µ-L)] (3), which form a linear polymer through intermolecular aurophilic contacts. The heterometallic TlI/AuIcomplex {[Au(C6F5)2Tl]2(L)}n(4) features a polymeric structural nature with a metallic pseudo-rhombic Au2Tl2core, which repeats itself forming a zig-zag polymer. In each Au2Tl2unit only one thallium atom is bonded by the NS3donor set of the macrocyclic ligand and also forms two unsupported Au-Tl bonds with two [Au(C6F5)2]-units in an overall pseudo-octahedral geometry. The other thallium atom similarly bridges the same [Au(C6F5)2]-units and links a neighbouring Au2Tl2moiety, thus exhibiting a distorted trigonal planar geometry being bonded only to three gold atoms with unsupported Au-Tl interactions. This complex displays an interesting thermochromic behaviour showing emissions mainly resulting from MM'CT transitions at room temperature. At 77 K a dual emission appears, probably arising from the two different thallium environments. DFT calculations have been carried out in the attempt to investigate the origin of the emissions of complex4. © The Royal Society of Chemistry 2021
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