Estudio de la especiación de disoluciones hidrolizadas mixtas Al-Fe en medio concentrado con el reactivo Ferrón.

Introducción. La obtención de disoluciones concentradas de aluminio con alta fracción de oligocationes presenta gran interés por su aplicabilidad como floculantes en el tratamiento de aguas y como agentes de intercalación de arcillas laminares. El análisis espectrofotométrico con el reactivo Ferrón permite obtener una distribución de las especies que se generan en disoluciones parcialmente hidrolizadas de Al3+, en base a su grado de polimerización. El propósito de este trabajo es evaluar el efecto de la relación de hidrólisis OH/(Al+Fe) (RH) y la concentración total de metales (CTM) sobre la preparación de disoluciones hidrolizadas de Al/Fe en medio concentrado. Para ello, se toma como criterio el contenido de los metales que queda representado al final en especies tipo Keggin (Al13), correspondiente a la fracción Alb obtenida mediante el análisis con el reactivo Ferrón [1]. Metodología. El efecto de la CTM y de la RH sobre la preparación de las disoluciones concentradas mixtas Al/Fe (DCMAF), se evaluó aplicando un diseño experimental 32, manteniendo constante la relación atómica nominal (Fe/(Al+Fe)) igual a 2,0. Cada factor se evaluó en tres niveles: para el factor CTM se emplearon los valores 0,2, 0,6 y 1,0 mol/L, mientras para el factor RH se tomaron los valores 2,0, 2,25 y 2,5. La preparación de las disoluciones se llevó a cabo partiendo de AlCl3.6H2O (Sigma Aldrich, 99,9%) y FeCl3.6H2O (Mallinckrodt, 99,5%) con lenta adición de disolución de hidróxido de sodio de concentración variable (Mallinckrodt, 99,8%), en un sistema de reflujo a 70 ºC durante 7,75 horas. Las disoluciones fueron filtradas en papel con tamaño de poro 0,45 μm para separar la fracción insoluble antes de ser analizadas. Para el análisis con el reactivo Ferrón (Sigma Aldrich, 98,5%) se empleó como patrón una disolución de concentración conocida de Al13, separado por precipitación del sulfato seguida de disolución del nitrato del oligocatión. La identidad del patrón se confirmó por difracción de rayos X en polvo. Las fracciones de Ala y Alb se determinaron midiendo la absorbancia a 364 nm a 1 y 120 minutos de reacción, respectivamente. Ala corresponde a la fracción de especies monoméricas, Alb a la fracción oligomérica soluble, y Alc a la fracción polimérica coloidal, calculada como Alc = AlT – (Ala + Alb). Resultados y discusión. La distribución de especies obtenida mediante el análisis con el reactivo Ferrón se muestra en la tabla 1. Tabla 1. Especiación de disoluciones concentradas mixtas Al/Fe (DCMAF) Los resultados muestran que a menor RH se favorece la fracción de especies poliméricas solubles Alb, aunque este efecto es menos marcado en cuanto baja CTM. Igualmente se observa, que con el aumento en CTM, Alb disminuye para un valor de RH. Cuando se incrementa CTM también se puede observar, que aunque baja el pH de equilibrio de las disoluciones se incrementa la fracción de polímeros inertes o coloidales de los metales, que corresponde a la fracción Alc con Ferrón. Conclusiones. La preparación de DCMAF con alto contenido de Al13 en medio concentrado se favorece con la disminución de RH. Bibliografía. 1. Parker, D.R. (1992). Identification and quantification of the “Al13” tridecameric polycation using ferron. Env. Sci. Technol. 26:908–914. Agradecimientos. Los autores agradecen la financiación de este trabajo a EMPOPASTO S.A, E.S.P mediante convenio específico de cooperación No 01 de 2008

Secreted protein acidic and rich in cysteine produced by human melanoma cells modulates polymorphonuclear leukocyte recruitment and antitumor cytotoxic capacity

The expression of secreted protein acidic and rich in cysteine (SPARC) has been associated with the malignant progression of different types of human cancer. SPARC was associated with tumor cell capacity to migrate and invade, although its precise role in tumor progression is still elusive. In the present study, we show that SPARC produced by melanoma cells modulates the antitumor activity of polymorphonuclear leukocytes (PMN). Administration to nude mice of human melanoma cells in which SPARC expression was transiently or stably knocked down by antisense RNA (SPARC-sup cells) promoted PMN recruitment and obliterated tumor growth even when SPARC-sup cells accounted for only 10% of injected malignant cells. In addition, SPARC-sup cells stimulated the in vitro migration and triggered the antimelanoma cytotoxic capacity of human PMN, an effect that was reverted in the presence of SPARC purified from melanoma cells or by reexpressing SPARC in SPARC-sup cells. Leukotrienes, interleukin 8, and growth-related oncogene, in combination with Fas ligand and interleukin 1, mediated SPARC effects. These data indicate that SPARC plays an essential role in tumor evasion from immune surveillance through the inhibition of the antitumor PMN activity.Facultad de Ciencias Veterinaria

Secreted protein acidic and rich in cysteine produced by human melanoma cells modulates polymorphonuclear leukocyte recruitment and antitumor cytotoxic capacity

The expression of secreted protein acidic and rich in cysteine (SPARC) has been associated with the malignant progression of different types of human cancer. SPARC was associated with tumor cell capacity to migrate and invade, although its precise role in tumor progression is still elusive. In the present study, we show that SPARC produced by melanoma cells modulates the antitumor activity of polymorphonuclear leukocytes (PMN). Administration to nude mice of human melanoma cells in which SPARC expression was transiently or stably knocked down by antisense RNA (SPARC-sup cells) promoted PMN recruitment and obliterated tumor growth even when SPARC-sup cells accounted for only 10% of injected malignant cells. In addition, SPARC-sup cells stimulated the in vitro migration and triggered the antimelanoma cytotoxic capacity of human PMN, an effect that was reverted in the presence of SPARC purified from melanoma cells or by reexpressing SPARC in SPARC-sup cells. Leukotrienes, interleukin 8, and growth-related oncogene, in combination with Fas ligand and interleukin 1, mediated SPARC effects. These data indicate that SPARC plays an essential role in tumor evasion from immune surveillance through the inhibition of the antitumor PMN activity.Facultad de Ciencias Veterinaria

Secreted protein acidic and rich in cysteine produced by human melanoma cells modulates polymorphonuclear leukocyte recruitment and antitumor cytotoxic capacity

The expression of secreted protein acidic and rich in cysteine (SPARC) has been associated with the malignant progression of different types of human cancer. SPARC was associated with tumor cell capacity to migrate and invade, although its precise role in tumor progression is still elusive. In the present study, we show that SPARC produced by melanoma cells modulates the antitumor activity of polymorphonuclear leukocytes (PMN). Administration to nude mice of human melanoma cells in which SPARC expression was transiently or stably knocked down by antisense RNA (SPARC-sup cells) promoted PMN recruitment and obliterated tumor growth even when SPARC-sup cells accounted for only 10% of injected malignant cells. In addition, SPARC-sup cells stimulated the in vitro migration and triggered the antimelanoma cytotoxic capacity of human PMN, an effect that was reverted in the presence of SPARC purified from melanoma cells or by reexpressing SPARC in SPARC-sup cells. Leukotrienes, interleukin 8, and growth-related oncogene, in combination with Fas ligand and interleukin 1, mediated SPARC effects. These data indicate that SPARC plays an essential role in tumor evasion from immune surveillance through the inhibition of the antitumor PMN activity.Facultad de Ciencias Veterinaria

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

A measurement of the production cross-section for top quark pairs(\ttbar) in $pp$ collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be $12.2 \pm 3.9$ events and $2.5 \pm 0.6$ events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction

Pulmonary Vascular Remodeling and Prognosis in Patients Evaluated for Heart Transplantation: Insights from the OCTOPUS-CHF Study

Objective: In patients with advanced heart failure, the intravascular optical coherence tomography (OCT) of subsegmental pulmonary artery measurements is correlated with right heart catheterization parameters. Our aim was to study the prognostic value of pulmonary OCT, right heart catheterization data, and the echocardiographic estimation of pulmonary pressure in patients studied for elective heart transplants. Methods: This research is an observational, prospective, multicenter study involving 90 adults with a one-year follow-up. Results: A total of 10 patients (11.1%) died due to worsening heart failure before heart transplantation, 50 underwent a heart transplant (55.6%), and 9 died in the first year after the transplant. The patients with and without events (mortality or heart failure-induced hospitalization) had similar data regarding echocardiography, right heart catheterization, and pulmonary OCT (with a median estimated pulmonary artery systolic pressure of 42.0 mmHg, interquartile range (IQR) of 30.3-50.0 vs. 47.0 mmHg, IQR 34.6-59.5 and p = 0.79, median pulmonary vascular resistance of 2.2 Wood units, IQR 1.3-3.7 vs. 2.0 Wood units, IQR 1.4-3.2 and p = 0.99, and a median pulmonary artery wall thickness of 0.2 +/- 0.5 mm vs. 0.2 +/- 0.6 mm and p = 0.87). Conclusion: Pulmonary vascular remodeling (evaluated with echocardiography, right heart catheterization, and pulmonary OCT) was not associated with prognosis in a selected sample of adults evaluated for elective heart transplants. Pulmonary OCT is safe and feasible for the evaluation of these patients

Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb−1 of √s=7 TeV proton-proton collisions

Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb−1 of pp collision data at s√=7TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≥6 to ≥9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m 0, gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV