Bloques de Tierra Comprimida (BTC) estabilizados con cal y cemento. Evaluación de su impacto ambiental y su resistencia a compresión

This work presents the evaluation of the environmental impact and compressive strength of Compressed Earth Blocks (CEB) stabilized with hydrated aerial lime and Portland cement. For this, 12 series of blocks stabilized with different proportions of lime and cement were manufactured and the Life Cycle Analysis (LCA) methodology was used. After conducting these assays and simulations, it could be concluded that, using earth and sand typical of the city of Santa Fe (Argentina), stabilized with certain percentages of Portland cement between 5 and 10% in weight, CEB can be produced with sufficient levels of strength for them to be used in load-bearing walls, in this way minimizing the negative environmental impact associated with their manufacturing. It is also concluded that the stabilization with aerial lime does not increase the CEB’s compressive strength and, on the contrary, significantly increases their negative impact on the environment.En este trabajo se presenta la evaluación del impacto ambiental y la resistencia a compresión de Bloques de Tierra Comprimida (BTC) estabilizados con cal aérea hidratada y cemento Portland. Para esa labor, se fabricaron 12 series de bloques estabilizados con diferentes proporciones de cal y cemento y se empleó la metodología del Análisis de Ciclo de Vida (ACV). Tras la realización de los ensayos y las simulaciones pudo concluirse que, usando suelos y arena característicos de la ciudad de Santa Fe (Argentina), estabilizados con determinados porcentajes de cemento Portland -comprendidos entre el 5 y el 10% en peso- pueden producirse BTC con niveles de resistencia suficientes para ser utilizados en muros de carga y, de esa forma, minimizar el impacto ambiental negativo asociado a su fabricación. Se concluye, además, que la estabilización con cal aérea no incrementa la resistencia a compresión de los BTC y aumenta, por el contrario, de manera significativa el impacto negativo de éstos sobre el medio ambiente

Slurry sampling in serum blood for mercury determination by CV-AFS

The heavy metal mercury (Hg) is a neurotoxin known to have a serious health impact even at relatively low concentrations. A slurry method was developed for the sensitive and precise determination of mercury in human serum blood samples by cold vapor generation coupled to atomic fluorescence spectrometry (CV-AFS). All variables related to the slurry formation were studied. The optimal hydrochloric concentration and tin(II) chloride concentration for CV generation were evaluated. Calibration within the range 0.1-10 μg L-1 Hg was performed with the standard addition method, and compared with an external calibration. Additionally, the reliability of the results obtained was evaluated by analyzing mercury in the same samples, but submitted to microwave-assisted digestion method. The limit of detection was calculated as 25 ng L-1 and the relative standard deviation was 3.9% at levels around of 0.4 μg L-1 Hg.Fil: Aranda, Pedro Rodolfo. Universidad Nacional de San Luis; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gil, Raul Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Moyano, Susana. Universidad Nacional de San Luis; ArgentinaFil: de Vito, Irma Esther. Universidad Nacional de San Luis; ArgentinaFil: Martinez, Luis Dante. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Luis; Argentin

Graphene-based materials as solid phase extraction sorbent for chromium(VI) determination in red wine

We report a novel and selective method for the preconcentration and determination of Cr(VI) in red wine through their adsorption on a tertiary amine, ALIQUAT 336, a commercial anionic exchanger extractant, widely used for the selective extraction of Cr(VI) over Cr(III). The determinations were made directly on the solid, by X-ray fluorescence spectrometry, method and large areas held by the graphene, making them a promising solid sorbent for preconcentration procedures, direct quantification of the analyte in the solid sorbent; there by reducing the number of reagents used thus minimizing handling of the sample. A high preconcentration factor was achieved for a very low volume of sample. The enrichment factor was calculated after considering that the thin film obtained from the 10 mL solution of 1 mg L−1 of Cr(VI) has a real thickness of 0.04 mm and a final diameter of 16.7 mm, so that the volume deposited on the pellet was 0.0088 cm3 and the preconcentration factor can be calculated to be 104.Fil: Fernández, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Fernández Baldo, Martín Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina; ArgentinaFil: Messina, Germán Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina; ArgentinaFil: Bertolino, Franco Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina; ArgentinaFil: Raba, Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina; ArgentinaFil: Aranda, Pedro Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina; Argentin

Copper nanoparticles applied to the preconcentration and electrochemical determination of β-adrenergic agonist: An efficient tool for the control of meat production

A novel method for preconcentration and electrochemical detection of zinterol in bovine urine samples was developed. In order to improve the limit of detection, the surface of a screen-printed carbon electrode was modified with electrodeposited metal copper nanoparticles. The experimental electro- deposition optimization was performed using a central composite design (CCD), involving the variables: precursor concentration, potential and time applied. Copper nanoparticles were characterized by transmission electron microscopy, scanning electron microscopy, cyclic voltammetry, and energy dispersive X-ray spectroscopy. Mesoporous shuttle-like copper oxide nanoparticles were used for the preconcentration step to avoid interferences with many compounds present in the sample matrix. The optimal working conditions for the preconcentration approach were found by means of both two-level fractional factorial and CCD designs. The obtained enhancement factor for a sample volume of 30 mL was 35 fold. The calibration curve showed linearity between 0.5 and 45 ng mL-1 and the limit of detection was 0.16 ng mL-1. The intra and inter assay coefficients of variability were below 4% and 5%; respectively.Fil: Regiart, Daniel Matias Gaston. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; Argentina. Universidad Nacional de San Luis; ArgentinaFil: Escudero, Luis Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; Argentina. Universidad Nacional de San Luis; ArgentinaFil: Aranda, Pedro Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; Argentina. Universidad Nacional de San Luis; ArgentinaFil: Martinez, Noelia Anabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; Argentina. Universidad Nacional de San Luis; ArgentinaFil: Bertolino, Franco Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; Argentina. Universidad Nacional de San Luis; ArgentinaFil: Raba, Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; Argentina. Universidad Nacional de San Luis; Argentin

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

LIF based fluorescent immunosensor using AP-SNs and QDs for quantitation of IgG anti Toxocara canis in human serum samples

Toxocariasis, one of the most common zoonotic infection worldwide, is caused by Toxocara canis (T. canis), or less commonly, Toxocara cati [1,2]. In humans, the infection is acquired by oral route through accidental ingestion of infective eggs from soil-contaminated hands, consumption of poorly sanitized vegetables and raw or undercooked meats [3,4]. Toxocara infective eggs hatch into the first portion of the intestine. Subsequently, the juvenile stages are distributed throughout the body, generating symptoms from mild to severe manifestations. The possibility of early diagnosis is of great importance, allowing proper management and treatment of patients suffering from toxocariasis. In last years, nanotechnology has contributed to the development of miniaturized immunosensor-based devices with high-throughput analytical properties [5,6]. Different nanomaterials such as quantum dots (QDs), silica nanoparticles (SNs), and other nanoparticles have emerged as promising alternatives for a wide range of immunosensors applications. The objective of this work was to develop a microfluidic immunosensor that include the use of nanomaterials for the quantitative determination of IgG antibodies to IgG anti-T.canis. For the development of the microfluidic immunosensor, excretory-secretory antigens from T. canis second-stage larvae (TES) were obtained according to the technique described by Gillespie (1995) [7]. The IgG anti-T.canis antibodies detection in serum samples were carried out using a non-competitive format immunoassay. TES immobilized on 3-aminopropyl-functionalized silica-nanoparticles (AP-SNs) covalently incorporated in the central channel of the device are recognized specifically by the anti-T. canis antibodies in the sample. The subsequent detection was achieved by adding a second antibody labeled with cadmium selenide zinc sulfide quantum dots (CdSe-ZnS QDs) specific to human IgG. The concentration of IgG anti-T. canis antibodies present in the serum sample was measured by LIF detector, using excitation lambda at 491 nm and emission at 540 nm. Relevant studies of experimental variables that affect the performance of microfluidic immunosensor for IgG anti-T. canis antibodies determination were done. Between them, the optimal flow rate, incubation time, concentration of TES to be immobilized, enzymatic activity and the amplification effect resulting from the incorporation of the AP-SNs, were studied The combination of two different nanomaterials; AP-SNs as bioaffinity supports and QDs as fluorescent labels, enabled us to achieve a useful alternative tool for T. canis diagnostic. SNs proved to be an excellent choice for optical sensing, increasing the active area and consequently the sensitivity. The total assay time was 30 minutes, having made LIF detection in less than 1 minute. The detection limit calculated for the proposed methodology was 0.12 ng mL-1 and the coefficients of intra- and inter-assay variation were less than 6%. The results show the usefulness of the developed immunosensor for the fast determination of IgG antibodies anti T. canis.Fil: Messina, Germán Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Aranda, Pedro Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Pereira, Sirley Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Bertolino, Franco Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Raba, Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentin

Orientación vocacional y tutorías para evitar la deserción estudiantil

Se ha pretendido con este trabajo crear un espacio de encuentro que promueva el diálogo entre los profesores, tutores estudiantes sobres el procesos de instrumentación de los programas tutoriales. Teniendo como objetivos principales: presentar, analizar y volcar el proceso tutorial como una herramienta para la mejora educativa. Contribuir en la elaboración de un instrumento descriptivo que permita recoger información general del alumno: Sistematizar la información para el análisis de los índices de desgranamiento y deserción de los alumnos en la Universidad durante el primer año de estudio.Fil: Aranda, Pedro Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Bertolino, Franco Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Barbato, María Inés. No especifíca

Determinación de mercurio en muestras biológicas por absorción atómica mediante extracción de punto nube

Acerca de los problemas asociados con algunos metales y su metalurgia, ya el historiador griego Plutarco relataba, hace más de 1900 años, lo que ahora denominaríamos severos efectos nocivos ambientales y sanitarios provocados por la exposición que experimentaban los trabajadores de las minas y fundiciones. Al mismo tiempo, corresponde enfatizar que numerosos metales pesados son necesarios para los seres vivos. Efectivamente, vestigios de cadmio, cobre, cromo y zinc, son esenciales para la vida. Además, algunos de los denominados metales pesados ingresan habitualmente a nuestro organismo vehiculizados por los alimentos, el agua o el aire que respiramos.Fil: Aranda, Pedro Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Pereira, Sirley Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Fernández Baldo, Martín Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentin