ISSN: 2310-2799
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546,196 artículos
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Año:
2018
ISSN:
0717-9707, 0717-9324
Sakthinathan, S. Pazhinivel; Suresh, Ramamoorthy; Kamalakkannan, Dakshnamoorthy; Mala, Veerandiran; Sathiyamoorthi, Kaliyan; Vanangamudi, Ganesan; Thirunarayanan, Ganesamoorthy
Sociedad Chilena de Química
Resumen
A series of aryl imines have been synthesized by SiO2-H3PO4 catalyzed microwave assisted condensation of amine and aldehyde under solvent-free conditions. The yield of the imines has been found to be more than 80%. The purity of all imines has been checked using their physical constants and spectral data as published earlier in literature. The UV λmax(nm), infrared νC=N(cm-1), NMR δ(ppm) of C-H and C=N spectral data have been correlated with Hammett substituent constants and F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effect of substituents on the above spectral data has been studied. The antimicrobial activities of all imines have been studied using Bauer-Kirby method.
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Año:
2018
ISSN:
0717-9707, 0717-9324
Urzúa, L.; Pérez-Ortiz, M.; Álvarez-Lueje, A.
Sociedad Chilena de Química
Resumen
A carbon paste electrode was modified with the ionic liquid 1-methyl-3-octyl imidazolium hexafluorophosphate and it was applied for study the electrocatalytic oxidation and voltammetric determination of the drug sulfamethazine. The developed modified electrode was characterized using cyclic voltammetry and scanning electron microscopy. The oxidation of sulfamethazine at the surface of modified electrode occurs at lower potentials than that of an unmodified carbon paste electrode, and both an enhancement of the anodic peak current and a signal narrower and better defined with the modified electrode were observed. Accordingly, a method for the determination of sulfamethazine was developed using differential pulse voltammetry, at pH 11 and with an accumulation time of 3 min. The oxidation of sulfamethazine exhibited a dynamic range between 30 and 300 μg/mL and detection and quantitation limits of 54 and 61 μg/mL, respectively. The method was applied to the determination of sulfamethazine in a veterinary commercial solution.
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Año:
2018
ISSN:
0717-9707, 0717-9324
Lashgari, Amir; Ghamami, Shahriar; Govindarajan, M.; Salgado-Morán, Guillermo; Montes Romero, Paola; Gerli Candia, Lorena
Sociedad Chilena de Química
Resumen
A theoretical quantum study of the organophosphorus compound with formula C10H19OPCl2 (MEPCL2) was carried out. The results of the calculations show excellent agreement between experimental and computed frequencies evaluated at the B3LYP/6-311++G(d,p) level of theory. A study of the electronic properties, such as excitation energies and wavelengths were performed employing the time-dependent DFT (TD-DFT) method. Global a chemical reactivity of MEPCL2 was analyzed through global reactivity descriptors, while its local reactivity was analyzed by mean maps of the electrostatic potential. Also, the orbital energies values suggest that a charge transfer is occurring within the molecule.
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Año:
2018
ISSN:
0717-9707, 0717-9324
Tapiero, Yesid; Rivas, Bernabé L.; Sánchez, Julio; Avila, Enrique G.
Sociedad Chilena de Química
Resumen
Macroporous polypropylene (MPP) membranes incorporating poly[sodium (styrene sulphonate)], P(SSNa), and poly[(ar-vinylbenzyl) trimethylammonium chloride],P(ClVBTA) were modified via “in situ” radical polymerization. Modified and unmodified MPP were characterized using SEM and charge density properties. Donnan dialysis was used to transport chromium ions. The results show that the degree of modification varied between 2.5% and 4.0%, and the water uptake percentage varied between 15% and 20%. Experimental data for chromium ion transport (Cr(III) and Cr(VI)) were fitted to a mathematical model, and a correlation coefficient very close to 1 was obtained. The main parameters of this mathematical fit are k and a. These parameters report the concentration of chromium ions that converge in the Donnan equilibrium (k) and the response rate of the modified membrane (a).
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Año:
2018
ISSN:
0717-9707, 0717-9324
Brito, Iván; Borquez, Jorge; Muñoz, Ruben; Cárdenas, Alejandro
Sociedad Chilena de Química
Resumen
The structure of this 14α-acetoxy-13α-hydroxymulin-11-en-20-oic acid monohydrate consists of a mulinane skeleton and the corresponding isopropyl, methyl, carboxyl and methyl groups at C3, C8, C5, C13, respectively, which are β-oriented, whereas the hydroxyl and acetoxy groups at C13 and C-14 are α-oriented. The cyclopentane (A), cyclohexane (B) and cycloheptene (C) rings are trans (A/B) and (B/C) cis fused, and in an envelope, chair, and twist conformation respectively. In the crystal the organic molecules are linked by the water molecules by two intermolecular OH⋅⋅⋅O hydrogen bond forming 1D-dimensional chains with graph-set notation (9).
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Año:
2018
ISSN:
0717-9707, 0717-9324
Da Silva, Paulo A. B.; De Souza, Gustavo C. S.; Paim, Ana Paula S.; Lavorante, André F.
Sociedad Chilena de Química
Resumen
A multicommuted flow procedure for the spectrophotometric determination of reducing sugars in wine has been developed. A dialysis unit was incorporated in the system to minimize matrix interferences and eliminate the colored compounds of the wine. The oxidation-reduction reaction in an alkaline medium between reducing sugars and the Cu2+-Neocuproine complex was employed. The compound formed was monitored at 460 nm. In the proposed procedure, there was a linear response between 0.25 and 4.0 g L-1 reducing sugars (y = (0.36 ± 0.02) + (0.31 ± 0.01) * x, R = 0.9975, n = 6), a coefficient of variance of 2.6% for a reducing sugar solution of 2.0 g L-1 (n = 7), a limit of detection estimated at 0.03 g L-1, reagent consumption per determination of 0.330, 0.128 and 0.160 mg for neocuproine, CuSO4 and NaOH, respectively. A sampling throughput of 45 determinations per hour was achieved. The proposed system was applied to wine samples and comparing the results with an AOAC official method no significant difference at a 95% confidence level.
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Año:
2018
ISSN:
2250-6950, 0327-4934
Lanteri, Sol
Universidad Nacional del Litoral
Resumen
Se trata de una reseña de la obra de de Juan Luis Martirén, Buenos Aires, Prometeo / Asociación Argentina de Historia Económica, 266 pp.
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Año:
2018
ISSN:
2250-6950, 0327-4934
Serra, María Nazaret
Universidad Nacional del Litoral
Resumen
The article makes the academic trajectories of migrant scientists who, after returning to the country, inserted themselves in institutional spaces in the city of Santa Fe by the scientific researcher career offered by CONICET. Data and strategies of quantitative and qualitative analysis were used, in order to characterize statistically the contexts and journeys of those who return. It was observed that, although they are linear trajectories with respect to events and significant transitions, the main differences are produced by gender, incentives for return and previous academic experience in the place of reintegration.
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Año:
2018
ISSN:
2250-6950, 0327-4934
Berardi Spairani, Adrian Pablo
Universidad Nacional del Litoral
Resumen
En este artículo proponemos dar cuenta de la forma en que los clivajes políticos influyen en las biografías militantes; nos preocupa responder si el contexto político constituye un elemento a tomar en cuenta para el mantenimiento del compromiso militante y de qué forma. Para llevar adelante estos objetivos analizaremos las trayectorias de dos militantes partidarios que comenzaron su participación política en la década del 2000, retomando la perspectiva de carrera propuesta por Howard Becker, considerando la trayectoria como un modelo de secuencias ordenadas de comportamiento social, tomando en cuenta los aspectos objetivos y subjetivos forma en que relata su propia historia).
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Año:
2018
ISSN:
2250-6950, 0327-4934
Petitti, Eva Mara
Universidad Nacional del Litoral
Resumen
Se trata de una reseña de la obra de Bernardo Carrizo y Juan Cruz Giménez (coordinadores). La política en las tramas educativas. Paraná, Fundación editorial La Hendija, 2017, pp. 410.
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