Activity coefficients of hydrocarbons at infinite dilution in di-n-octyltin dichloride: comparison with results obtained in other alkyltin solvents

The gas chromatographic method was employed to measure the infinite dilution activity coefficients of twenty-eight hydrocarbons of different types in di-n-octyltin dichloride between 323.15 and 353.15 K, and ofseven branched alkanes in tri-n-octyltin chloride between 313.15 and 333.15 K. A comparison is made between the results obtained for all the solutes in both solvents and in tetra-n-octyltin

Preparación y caracterización fisicoquímica de compost para fertilización de Rubus glaucus (Mora de Castilla)

Se presentan resultados de la elaboración y caracterización de diferentes compost para fertilización utilizando: Eisenia foetida (lombriz californiana) y compostaje aerotérmico. Durante la preparación se monitorearon características de pH, temperatura, humedad, nutrientes y poblaciones microbianas del suelo. Los sistemas se caracterizaron por diferentes métodos fisicoquímicos: DRX; Microscopía Electrónica SEM-EDS; espectroscopia FT-IR y análisis higroscópico por láser Speckle dinámico. Se intentó correlacionar los cambios fisicoquímicos del suelo con los compostajes. También se estimó la capacidad hidroadsorbente de compost, a partir de la actividad de Speckle dinámico

Caracterización de hidroadsorción de aluminosilicatos por la técnica de speckle

Las propiedades higroscópicas de aluminosilicatos son de importancia en aplicaciones como adsorbentes y en procesos catalíticos. Con el fin de estimar su potencialidad tecnológica, en general estos materiales se caracterizan mediante técnicas fisicoquímicas tales como adsorción de Nitrógeno, (BET), DRX, FTIR, SEM-EDS etc. En este trabajo se emplea una técnica óptica denominada speckle para el estudio de la hidroadsorción de materiales porosos a base de clinoptilolita, una zeolita natural. El método presenta algunas ventajas en comparación con las técnicas convencionales mencionadas. Se muestran resultados experimentales preliminares y se comentan algunas de las posibilidades futuras de aplicación

Cultivating consciousness with science

El proyecto Cultivando Consciencia con Ciencia propone el establecimiento de una granja agroecológica en la comunidad educativa de la Escuela N° 263 Provincia de Catamarca, del Barrio El Molino de la Ciudad de Belén, Departamento Belén, Provincia de Catamarca. Avances en su implementación demostraron oportunidades de aprendizaje combinando contenidos de primer y segundo ciclo de la educación formal con la producción de alimentos en una granja agroecológica, la formación en valores ecológicos y el trabajo en equipo. Para los actores involucrados en el proyecto, el espacio que se construye permite vivenciar valiosas experiencias. Docentes investigadores junto a estudiantes avanzados de Agronomía y becarios intervienen con acciones de capacitación teórico-prácticas para la elaboración de secuencias didácticas que estimule el aprendizaje científico basado en la indagación, permitiendo al capacitando explorar, descubrir y desarrollar nuevos conocimientos aplicados a necesidades concretas de su contexto. En estas instancias, la difusión de información científico técnica crea condiciones que asegura que se enseñe lo que se necesita, que lo enseñado se aprenda y que lo aprendido sea transferido a otros problemas.The project “Cultivating consciousness with science” proposes locating an agroecological farm in the educational community of School N° 263 Province of Catamarca, District El Molino, Belén Department, Province of Catamarca. Developments in its implementation proved learning opportunities by combining contents of first and second cycle of formal education with food production in an agroecological farm, as well as training in ecology values and teamwork. For the actors participating in the project, the space built provides valuable experiences. Teachers-researchers together with advanced agronomy students and scholarships play an important role through theoretical-practical training actions for the elaboration of didactic sequences that stimulate scientific learning based on research. This allows students to explore, discover and develop new knowledge applied to their contextual specific needs. In this context, technical scientific knowledge dissemination creates conditions to ensure the teaching of what is needed by students. Also, to promote learning and knowledge and their transfer to other problems.Fil: Denett, Gabriel Omar. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; ArgentinaFil: Barros, Lucas Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; ArgentinaFil: Denett, Yanina Lorena. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; ArgentinaFil: Espeche, Lucas Javier. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; ArgentinaFil: Campos Olmos, María Virginia. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; ArgentinaFil: Lencina, Sibila Ivonne. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; ArgentinaFil: Soria, Rosana R.. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; ArgentinaFil: Mohamed, Carolina B.. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; ArgentinaFil: Salas, Monica Delia. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; ArgentinaFil: Cisterna Fernandez, Maria Ines. Universidad Nacional de Catamarca. Facultad de Tecnología y Cs.aplicadas. Departamento de Formación Basica; ArgentinaFil: Ortiz, Erlinda del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Catamarca. Facultad de Tecnología y Ciencias Aplicadas; Argentina. Universidad Nacional de Catamarca. Facultad de Tecnología y Ciencias Aplicadas. Instituto de Monitoreo y Control de la Degradación Geoambiental; ArgentinaFil: Comelli, Nieves Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Catamarca. Universidad Nacional de Catamarca. Centro de Investigaciones y Transferencia de Catamarca; Argentina. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; Argentin

Role of age and comorbidities in mortality of patients with infective endocarditis

Purpose: The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality. Methods: Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015. Patients were stratified into three age groups:<65 years, 65 to 80 years, and = 80 years.The area under the receiver-operating characteristic (AUROC) curve was calculated to quantify the diagnostic accuracy of the CCI to predict mortality risk. Results: A total of 3120 patients with IE (1327 < 65 years;1291 65-80 years;502 = 80 years) were enrolled.Fever and heart failure were the most common presentations of IE, with no differences among age groups.Patients =80 years who underwent surgery were significantly lower compared with other age groups (14.3%, 65 years; 20.5%, 65-79 years; 31.3%, =80 years). In-hospital mortality was lower in the <65-year group (20.3%, <65 years;30.1%, 65-79 years;34.7%, =80 years;p < 0.001) as well as 1-year mortality (3.2%, <65 years; 5.5%, 65-80 years;7.6%, =80 years; p = 0.003).Independent predictors of mortality were age = 80 years (hazard ratio [HR]:2.78;95% confidence interval [CI]:2.32–3.34), CCI = 3 (HR:1.62; 95% CI:1.39–1.88), and non-performed surgery (HR:1.64;95% CI:11.16–1.58).When the three age groups were compared, the AUROC curve for CCI was significantly larger for patients aged <65 years(p < 0.001) for both in-hospital and 1-year mortality. Conclusion: There were no differences in the clinical presentation of IE between the groups. Age = 80 years, high comorbidity (measured by CCI), and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in the <65-year group

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Tantalum Chloride Species Incorporating Anionic and Cationic Guanidine components

Attempted preparation of tantalum complexes incorporating the anionic guanidinate ligand derived from 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (hppH) are reported. Reaction of (hpp)SiMe3 and TaCl5 in a 1:1 ratio gave the bis-guanidinate compound rather than the expected mono-ligand species. Reaction of 2 equiv. of (hpp)SiMe3 or in situ generated [hpp]Li with TaCl5 afforded a solid which analysed correctly for the compound (hpp)2TaCl3. X-ray structural analysis of the crystallised product identified the coordination isomer [Ta(hpp)4][TaCl6], with a distorted dodecahedral cation and a regular octahedral anion. During the course of this study, two closely related hydrolysis products, [(hppH2)]2[{TaCl6}{Cl}] and [(hppH2)]3[{TaCl6}2{Cl}]eCN were isolated and structurally characterised, each containing [hppH2]+ cations and [Cl]¿ and [TaCl6]¿ anions in extended arrays, linked by intermolecular hydrogen bonds

Stabilisation of High Oxidation-State Niobium Using 'Electron-Rich' Bicyclic-Guanidinates

Synthetic procedures to high oxidation-state complexes of niobium incorporating the bicyclic guanidinate 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinate, [hpp]¿, are described. The ligand source was either the N-trimethylsilylated guanidine or the lithium guanidinate and the reaction proceeded via elimination of trimethylsilylchloride or transmetallation from NbCl5, respectively. A 1:1 ratio of reagents afforded the mono-ligand product, Nb(hpp)Cl4 (1) and crystallisation from acetonitrile afforded the solvated species Nb(hpp)Cl4(MeCN) (1a), demonstrating the ability of the metal centre in 1 to bind small substrate molecules. A 2:1 ratio of lithium guanidinate to NbCl5 resulted in formation of the seven-coordinate, bis-ligand compound, Nb(hpp)2Cl3 (2). These products represent the first examples of guanidinate compounds in which niobium is stable in the +5 oxidation-state, believed to result from enhanced electron donation caused by the bicyclic framework of the ligand. The molecular structures of 1, 1a and 2 are reported, presenting for the first time an opportunity to describe bonding parameters within compounds of this type

Structural Diversity in the Coordination of Amidines and Guanidines to Monovalent Metal Halides

A series of structurally characterised, monovalent metal-halide complexes incorporating neutral amidine and guanidine ligands is reported. N,N-diphenylbenzamidine reacted with copper(I) chloride to afford the bis-ligand complex [CuCl(PhC{NPh}{NHPh})2]2(1), that exists as a chlorine bridged dimer in the solid state, with a non-symmetrical distribution of NHCl interactions within the Cu2Cl2 metallacycle. In contrast, only one equivalent of the guanidine, Me2NC{NiPr}{NHiPr}(2), is coordinated in the copper(I) iodide complex [CuI(Me2NC{NiPr}{NHiPr})]2(3), which was also isolated as the dimer with bridging halide atoms. The molecular structure of the bicyclic guanidine, 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (hppH), is reported, revealing a hydrogen bridged dimer with extensive delocalisation throughout the ligand framework. Coordination of hppH to lithium chloride afforded the dimeric bis-ligand complex [LiCl(hppH)2]2(4) in which each hppH molecule interacts with a different chlorine atom of the central Li2Cl2 core of the molecule via NHCl hydrogen bonding. In contrast the 2 1 ligand to metal complex is formed with silver(I) chloride to afford AgCl(hppH)2(5), a unique example of a monomeric, three-coordinate silver chloride supported by nitrogen-based ligands. The series of mixed ligand complexes [CuX(hppH)(PPh3)]n(6, X = Cl, n= 1; 7, X = Br, n= 2; 8 X = I, n= 2) have also been synthesised and structurally characterised, allowing comparisons of the relative coordinating behaviour of hppH and PPh3 as neutral donors at copper(I) centres to be made