24 research outputs found

    Interaction of heavy metals and different organic matrixes

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    El objetivo general de este trabajo es estudiar la forma de interacción entre tres matrices orgánicas diferentes y los metales pesados. Con este propósito, se diseñaron, sintetizaron y evaluaron tres nuevas matrices para ser utilizadas como agentes secuestrantes de metales pesados. Estos nuevos materiales son de naturaleza química diversa: polímeros, tensioactivos derivados de hidratos de carbono y biomasa muerta. Los tensioactivos presentados son derivados de alquil glucósidos, diseñados para obtener sustituyentes con capacidades quelantes en sus cabezas hidrofílicas. La obtención de estos compuestos se llevó a cabo mediante una síntesis en tres etapas. En una primer paso se produce la O-glicosidación de una unidad de glucosa con un alcohol graso. En una segunda etapa se realiza la conversión del grupo alcohol en C6 de la unidad de glucosa a ácido carboxílico. Finalmente en la última etapa se produce el acoplamiento de diferentes grupos funcionales en el carboxilo del ácido glucurónico buscando obtener la función quelante. Los ensayos para la remoción de metales pesados se llevaron a cabo empleando el método conocido como flotación. Las propiedades interfaciales de todos productos obtenidos son caracterizadas, así como también los equilibrios de formación de complejos para los productos más eficaces. La eficiencia de remoción es discutida en detalle en función de las propiedades estudiadas. El material polimérico utilizado es un polímero con sustituyentes tetrazólicos. Este producto es obtenido mediante una sencilla modificación química efectuada sobre fibras de un copolímero de acrilonitrilo que es un descarte industrial. La transformación consiste en una cilcoadición dipolar 1,3. El material así sintetizado demostró ser aplicable en la precipitación de metales pesados divalentes, presentando además la ventaja de ser reutilizable. Todos los materiales obtenidos, son caracterizados física, térmica y espectroscópicamente, con el objetivo de comprender la forma de interacción. La biomasa fue obtenida a partir del hongo macroscópico polyporus tenuiculus sin mayores tratamientos y fue utilizada como sorbente para metales pesados divalentes, en soluciones mono- y multi-sorbato. Se caracteriza la cinética, las isotermas de sorción y la dependencia de la eficiencia de remoción con los factores experimentales. El sorbente demuestra ser eficiente para remoción de metales pesados, presentando la ventaja se ser reutilizable. Se comparan las ventajas y desventajas en la utilización de las tras matrices estudiadas.The overall objective of this work is to study the interaction between three different organic matrixes with heavy metals. For this purpose, three new matrixes for use as heavy metal sequestering agents were designed, synthesized and evaluated. These new materials are of different chemical nature: polymers, surfactants derived from carbohydrates, and dead biomass. The studied surfactants are derived from alkyl glucosides, designed with substituents having chelating capabilities in their hydrophilic heads. The preparation of these compounds is carried out by a three-step synthesis. In a first stage occurs the O-glycosylation of a glucose unit with a fatty alcohol. In a second stage the alcohol group in the C6 of the glucose unit is converted in carboxylic acid. Finally, in the last stage, different functional groups are coupled to the carboxyl group of the glucuronic acid, and so, the desired chelating function is obtained. The tests for removing the heavy metals were carried out using the method known as flotation. Interfacial properties of all the products obtained are characterized as well as the complexation equilibria for the most effective products. Removal efficiency is discussed in detail in terms of the properties studied. The polymeric material used is a polymer with tetrazolic pendan group. This product was obtained by a simple chemical modification conducted on the fibers of a copolymer which is an industrial waste. The transformation consists in a dipolar cyclo addition 1,3. The material thus synthesized proved to be applicable in the precipitation of divalent heavy metals, also having the advantage of being reusable. All materials obtained were characterized physical, thermal and spectroscopically, with the aim of understand the mechanism of interaction. Biomass was obtained from the macroscopic fungus polyporus tenuiculus without further treatment and was used as a sorbent for divalent heavy metals, in mono- and multi-sorbate solutions. Kinetics, sorption isotherms and dependence of removal efficiency are characterized with the experimental factors. The sorbent proved be efficient for the removal of heavy metals, and showed the advantage of being reusable. The advantages and disadvantages in the use of the three studied matrixes are compared.Fil: Grassi, Diego Alejandro. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

    Enabling planetary science across light-years. Ariel Definition Study Report

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    Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, was adopted as the fourth medium-class mission in ESA's Cosmic Vision programme to be launched in 2029. During its 4-year mission, Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System. The payload consists of an off-axis Cassegrain telescope (primary mirror 1100 mm x 730 mm ellipse) and two separate instruments (FGS and AIRS) covering simultaneously 0.5-7.8 micron spectral range. The satellite is best placed into an L2 orbit to maximise the thermal stability and the field of regard. The payload module is passively cooled via a series of V-Groove radiators; the detectors for the AIRS are the only items that require active cooling via an active Ne JT cooler. The Ariel payload is developed by a consortium of more than 50 institutes from 16 ESA countries, which include the UK, France, Italy, Belgium, Poland, Spain, Austria, Denmark, Ireland, Portugal, Czech Republic, Hungary, the Netherlands, Sweden, Norway, Estonia, and a NASA contribution

    Goodbye Hartmann trial: a prospective, international, multicenter, observational study on the current use of a surgical procedure developed a century ago

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    Background: Literature suggests colonic resection and primary anastomosis (RPA) instead of Hartmann's procedure (HP) for the treatment of left-sided colonic emergencies. We aim to evaluate the surgical options globally used to treat patients with acute left-sided colonic emergencies and the factors that leading to the choice of treatment, comparing HP and RPA. Methods: This is a prospective, international, multicenter, observational study registered on ClinicalTrials.gov. A total 1215 patients with left-sided colonic emergencies who required surgery were included from 204 centers during the period of March 1, 2020, to May 31, 2020. with a 1-year follow-up. Results: 564 patients (43.1%) were females. The mean age was 65.9 ± 15.6 years. HP was performed in 697 (57.3%) patients and RPA in 384 (31.6%) cases. Complicated acute diverticulitis was the most common cause of left-sided colonic emergencies (40.2%), followed by colorectal malignancy (36.6%). Severe complications (Clavien-Dindo ≥ 3b) were higher in the HP group (P < 0.001). 30-day mortality was higher in HP patients (13.7%), especially in case of bowel perforation and diffused peritonitis. 1-year follow-up showed no differences on ostomy reversal rate between HP and RPA. (P = 0.127). A backward likelihood logistic regression model showed that RPA was preferred in younger patients, having low ASA score (≤ 3), in case of large bowel obstruction, absence of colonic ischemia, longer time from admission to surgery, operating early at the day working hours, by a surgeon who performed more than 50 colorectal resections. Conclusions: After 100 years since the first Hartmann's procedure, HP remains the most common treatment for left-sided colorectal emergencies. Treatment's choice depends on patient characteristics, the time of surgery and the experience of the surgeon. RPA should be considered as the gold standard for surgery, with HP being an exception

    Calibration of the CMS hadron calorimeters using proton-proton collision data at root s=13 TeV

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    Methods are presented for calibrating the hadron calorimeter system of theCMSetector at the LHC. The hadron calorimeters of the CMS experiment are sampling calorimeters of brass and scintillator, and are in the form of one central detector and two endcaps. These calorimeters cover pseudorapidities vertical bar eta vertical bar ee data. The energy scale of the outer calorimeters has been determined with test beam data and is confirmed through data with high transverse momentum jets. In this paper, we present the details of the calibration methods and accuracy.Peer reviewe

    ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider

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    Interaction of heavy metals and different organic matrixes

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    El objetivo general de este trabajo es estudiar la forma de interacción entre tres matrices orgánicas diferentes y los metales pesados. Con este propósito, se diseñaron, sintetizaron y evaluaron tres nuevas matrices para ser utilizadas como agentes secuestrantes de metales pesados. Estos nuevos materiales son de naturaleza química diversa: polímeros, tensioactivos derivados de hidratos de carbono y biomasa muerta. Los tensioactivos presentados son derivados de alquil glucósidos, diseñados para obtener sustituyentes con capacidades quelantes en sus cabezas hidrofílicas. La obtención de estos compuestos se llevó a cabo mediante una síntesis en tres etapas. En una primer paso se produce la O-glicosidación de una unidad de glucosa con un alcohol graso. En una segunda etapa se realiza la conversión del grupo alcohol en C6 de la unidad de glucosa a ácido carboxílico. Finalmente en la última etapa se produce el acoplamiento de diferentes grupos funcionales en el carboxilo del ácido glucurónico buscando obtener la función quelante. Los ensayos para la remoción de metales pesados se llevaron a cabo empleando el método conocido como flotación. Las propiedades interfaciales de todos productos obtenidos son caracterizadas, así como también los equilibrios de formación de complejos para los productos más eficaces. La eficiencia de remoción es discutida en detalle en función de las propiedades estudiadas. El material polimérico utilizado es un polímero con sustituyentes tetrazólicos. Este producto es obtenido mediante una sencilla modificación química efectuada sobre fibras de un copolímero de acrilonitrilo que es un descarte industrial. La transformación consiste en una cilcoadición dipolar 1,3. El material así sintetizado demostró ser aplicable en la precipitación de metales pesados divalentes, presentando además la ventaja de ser reutilizable. Todos los materiales obtenidos, son caracterizados física, térmica y espectroscópicamente, con el objetivo de comprender la forma de interacción. La biomasa fue obtenida a partir del hongo macroscópico polyporus tenuiculus sin mayores tratamientos y fue utilizada como sorbente para metales pesados divalentes, en soluciones mono- y multi-sorbato. Se caracteriza la cinética, las isotermas de sorción y la dependencia de la eficiencia de remoción con los factores experimentales. El sorbente demuestra ser eficiente para remoción de metales pesados, presentando la ventaja se ser reutilizable. Se comparan las ventajas y desventajas en la utilización de las tras matrices estudiadas.The overall objective of this work is to study the interaction between three different organic matrixes with heavy metals. For this purpose, three new matrixes for use as heavy metal sequestering agents were designed, synthesized and evaluated. These new materials are of different chemical nature: polymers, surfactants derived from carbohydrates, and dead biomass. The studied surfactants are derived from alkyl glucosides, designed with substituents having chelating capabilities in their hydrophilic heads. The preparation of these compounds is carried out by a three-step synthesis. In a first stage occurs the O-glycosylation of a glucose unit with a fatty alcohol. In a second stage the alcohol group in the C6 of the glucose unit is converted in carboxylic acid. Finally, in the last stage, different functional groups are coupled to the carboxyl group of the glucuronic acid, and so, the desired chelating function is obtained. The tests for removing the heavy metals were carried out using the method known as flotation. Interfacial properties of all the products obtained are characterized as well as the complexation equilibria for the most effective products. Removal efficiency is discussed in detail in terms of the properties studied. The polymeric material used is a polymer with tetrazolic pendan group. This product was obtained by a simple chemical modification conducted on the fibers of a copolymer which is an industrial waste. The transformation consists in a dipolar cyclo addition 1,3. The material thus synthesized proved to be applicable in the precipitation of divalent heavy metals, also having the advantage of being reusable. All materials obtained were characterized physical, thermal and spectroscopically, with the aim of understand the mechanism of interaction. Biomass was obtained from the macroscopic fungus polyporus tenuiculus without further treatment and was used as a sorbent for divalent heavy metals, in mono- and multi-sorbate solutions. Kinetics, sorption isotherms and dependence of removal efficiency are characterized with the experimental factors. The sorbent proved be efficient for the removal of heavy metals, and showed the advantage of being reusable. The advantages and disadvantages in the use of the three studied matrixes are compared.Fil: Grassi, Diego Alejandro. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

    Ariel: Enabling planetary science across light-years

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    Ariel Definition Study ReportAriel Definition Study Report, 147 pages. Reviewed by ESA Science Advisory Structure in November 2020. Original document available at: https://www.cosmos.esa.int/documents/1783156/3267291/Ariel_RedBook_Nov2020.pdf/Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, was adopted as the fourth medium-class mission in ESA's Cosmic Vision programme to be launched in 2029. During its 4-year mission, Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System. The payload consists of an off-axis Cassegrain telescope (primary mirror 1100 mm x 730 mm ellipse) and two separate instruments (FGS and AIRS) covering simultaneously 0.5-7.8 micron spectral range. The satellite is best placed into an L2 orbit to maximise the thermal stability and the field of regard. The payload module is passively cooled via a series of V-Groove radiators; the detectors for the AIRS are the only items that require active cooling via an active Ne JT cooler. The Ariel payload is developed by a consortium of more than 50 institutes from 16 ESA countries, which include the UK, France, Italy, Belgium, Poland, Spain, Austria, Denmark, Ireland, Portugal, Czech Republic, Hungary, the Netherlands, Sweden, Norway, Estonia, and a NASA contribution

    Ariel: Enabling planetary science across light-years

    No full text
    Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, was adopted as the fourth medium-class mission in ESA's Cosmic Vision programme to be launched in 2029. During its 4-year mission, Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System. The payload consists of an off-axis Cassegrain telescope (primary mirror 1100 mm x 730 mm ellipse) and two separate instruments (FGS and AIRS) covering simultaneously 0.5-7.8 micron spectral range. The satellite is best placed into an L2 orbit to maximise the thermal stability and the field of regard. The payload module is passively cooled via a series of V-Groove radiators; the detectors for the AIRS are the only items that require active cooling via an active Ne JT cooler. The Ariel payload is developed by a consortium of more than 50 institutes from 16 ESA countries, which include the UK, France, Italy, Belgium, Poland, Spain, Austria, Denmark, Ireland, Portugal, Czech Republic, Hungary, the Netherlands, Sweden, Norway, Estonia, and a NASA contribution

    Goodbye Hartmann trial: a prospective, international, multicenter, observational study on the current use of a surgical procedure developed a century ago /

    No full text
    Background: Literature suggests colonic resection and primary anastomosis (RPA) instead of Hartmann’s procedure (HP) for the treatment of left-sided colonic emergencies. We aim to evaluate the surgical options globally used to treat patients with acute left-sided colonic emergencies and the factors that leading to the choice of treatment, comparing HP and RPA. Methods: This is a prospective, international, multicenter, observational study registered on ClinicalTrials.gov. A total 1215 patients with left-sided colonic emergencies who required surgery were included from 204 centers during the period of March 1, 2020, to May 31, 2020. with a 1-year follow-up. Results: 564 patients (43.1%) were females. The mean age was 65.9 ± 15.6 years. HP was performed in 697 (57.3%) patients and RPA in 384 (31.6%) cases. Complicated acute diverticulitis was the most common cause of left-sided colonic emergencies (40.2%), followed by colorectal malignancy (36.6%). Severe complications (Clavien-Dindo ≥ 3b) were higher in the HP group (P < 0.001). 30-day mortality was higher in HP patients (13.7%), especially in case of bowel perforation and diffused peritonitis. 1-year follow-up showed no differences on ostomy reversal rate between HP and RPA. (P = 0.127). A backward likelihood logistic regression model showed that RPA was preferred in younger patients, having low ASA score (≤ 3), in case of large bowel obstruction, absence of colonic ischemia, longer time from admission to surgery, operating early at the day working hours, by a surgeon who performed more than 50 colorectal resections. Conclusions: After 100 years since the first Hartmann’s procedure, HP remains the most common treatment for left-sided colorectal emergencies. Treatment’s choice depends on patient characteristics, the time of surgery and the experience of the surgeon. RPA should be considered as the gold standard for surgery, with HP being an exception

    Goodbye Hartmann trial: a prospective, international, multicenter, observational study on the current use of a surgical procedure developed a century ago

    No full text
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