Cuando Cuba entró en París : retombées barthesianas en la crítica literaria de Severo Sarduy

En el presente artículo se exploran los usos barthesianos de la crítica literaria de Severo Sarduy. En primer lugar, analizamos de qué manera la lectura estructuralista-telquelista realizada por Sarduy sobre las obras de Góngora y Lezama Lima le permitió elaborar el concepto de neobarroco como rasgo identitario de la cultura cubana. En segundo lugar, vemos cómo a través de la práctica del "habla indirecta" barthesiana Sarduy acaba constituyendo una crítica literaria en la que Cuba se afirma y se cuestiona a la vez.En el present article s'exploren els usos barthesianos de la crítica literària de Sever Sarduy. En primer lloc, analitzem de quina manera la lectura estructuralista-telquelista realitzada per Sarduy sobre les obres de Góngora i Lezama Lima li va permetre elaborar el concepte de neobarroc com a tret identitari de la cultura cubana. En segon lloc, veiem com a través de la pràctica del "parla indirecta" barthesiana Sarduy acaba constituint una crítica literària en què Cuba s'afirma i es qüestiona alhora.This article explores the uses of Roland Barthes in Severo Sarduy's literary criticism. First, we analyse how the structuralist-telquelist reading operated by Sarduy on the works of Luis de Góngora and José Lezama Lima allowed him to develop the concept of neo-baroque as an identifying feature of Cuban culture. Secondly, we explain how Sarduy constructs an affirming but questioning literary critique of Cuba through the practice of the 'indirect language' of Barthes

Modelo de educación de la inteligencia colectiva

The research carried out is part of the field of study of Collective Intelligence (CI) with the use of Information and Communication Technologies (ICT) in Higher Education. The heart of this research was focused on the study, design and construction of electronic tools according to the paradigms of CI, to be applied in Higher Education. As an instrument for the implementation of these tools, an educational model with a collective work approach was designed. The research strategy used was Design-Based Research (DBR), because it investigates a phenomenon in its real context, iterative and incremental, and it is especially recommended for the field of education. DBR in each experimental cycle updates literature, model and tools. Empirical studies were conducted in four universities and fields of study in Latin America and Europe. The refinements demanded by the research strategy provided the scientific and empirical evidence to design ICT tools that meet the requirements of CI. In addition, the results indicate that the educational model and the tools have generated a positive perception in teachers and students about the effects on the teaching-learning process. Based on this fact, the experimental cycles present significant contributions to the research carried out around the CI with ICT tools in Higher Education.La investigación realizada se enmarca en el campo de estudio de la Inteligencia Colectiva (IC) con el uso de las Tecnologías de la Información y la Comunicaciones (TIC) en la Educación Superior. El corazón de ésta investigación estuvo enfocada en el estudio, diseño y construcción de herramientas electrónicas acorde a los paradigmas de IC, para ser aplicadas en la Educación Superior. Como vía de instrumentación de dichas herramientas, se diseñó un modelo educativo con enfoque de trabajo colectivo. La estrategia de investigación que se utilizó fue la Investigación Basada en el Diseño (DBR), porque investiga un fenómeno en su contexto real, es iterativa e incremental, y está especialmente recomendada para el ámbito de la educación.DBR en cada ciclo experimental actualiza literatura, modelo y herramientas. Los estudios empíricos se realizaron en cuatro universidades y campos de estudio en Hispanoamérica y Europa. Los múltiples refinamientos exigidos por la estrategia de investigación, proporcionaron la evidencia científica y empírica para diseñar herramientas TIC que cumplan con los requisitos de IC. Además, los resultados indican que el modelo educativo y las herramientas han generado una percepción positiva en docentes y estudiantes sobre los efectos en el proceso de enseñanza-aprendizaje. Basados en este hecho, los ciclos experimentales presentan aportes significativos a las investigaciones que se realizan en torno a la IC con herramientas TIC en la Educación Superior

Lancolides, Antiplatelet Aggregation Nortriterpenoids with Tricyclo[6.3.0.0^2,11]undecane-Bridged System from <i>Schisandra lancifolia</i>

A new class of highly oxygenated <i>Schisandra</i> nortriterpenoids, lancolides A–D (<b>1</b>–<b>4</b>), from <i>Schisandra lancifolia</i>, represents the first example of natural products that possess a tricyclo[6.3.0.0^2,11]undecane-bridged system. Their structures were elucidated by NMR spectra, X-ray diffraction, and quantum chemical calculations. Lancolides A (<b>1</b>) and D (<b>4</b>) had specific antiplatelet aggregation induced by platelet-activating factor (PAF)

Structural Characterization and Antioxidative Activity of Lancifonins: Unique Nortriterpenoids from <i>Schisandra lancifolia</i>

Six unique nortriterpenoids, lancifonins A–F (<b>1</b>–<b>6</b>), were isolated from <i>Schisandra lancifolia</i>. Their absolute configurations were determined by X-ray diffraction and ECD calculation. The conformational analysis of <b>1</b> was performed due to the unanticipated changes of Cotton effects in its ECD spectrum. Compounds <b>5</b> and <b>6</b> possess a unique 7/7 fused carbocyclic core with an internal ester bridge between C-9 and C-14, and <b>5</b> exhibited protective activity against H₂O₂-induced oxidative damage on Caco-2 cells

Schinortriterpenoids with Identical Configuration but Distinct ECD Spectra Generated by Nondegenerate Exciton Coupling

Ten schinortriterpenoids with biogenetically related lancischiartane scaffolds, including the first 3-norlancischiartane (<b>1</b>) with unusual configuration inversions occurring at C-1 and C-10, were isolated from <i>Schisandra lancifolia</i>. Unusual ECD curve patterns observed in <b>6</b>–<b>8</b> were confirmed to be caused by nondegenerate exciton coupling, suggesting that ECD spectrum empirical comparison should be used with caution in configuration determination. Additionally, structure revision of <b>2</b>, originally proposed as arisanlactone A, was completed using NMR computation and X-ray diffraction analysis

Rearranged 6/6/5/6-Fused Triterpenoid Acids from the Stems of <i>Kadsura coccinea</i>

Fourteen new rearranged 6/6/5/6-fused triterpenoid acids, namely, kadcoccine acids A–N (<b>1</b>–<b>14</b>), were isolated from an EtOAc-soluble extract of the stems of <i>Kadsura coccinea</i>. Their structures were characterized mainly by analyzing 1D and 2D NMR and HRESIMS data and were shown to feature a rare 14(13→12)-<i>abeo</i>-lanostane skeleton. Compounds <b>7</b> and <b>8</b> represented the first examples of a 5-substituted 2­(5<i>H</i>)-furanone motif on the C-17 side chain of this skeleton. The absolute configurations of C-23 for compounds <b>1</b>, <b>7</b>, and <b>8</b> were determined by comparison of their experimental electronic circular dichroism spectra. All the isolates were screened for their in vitro cytotoxicity against six human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7, SW-480, and HeLa), and compounds <b>2</b> and <b>8</b> exhibited weak inhibitory effects with IC₅₀ values ranging from 3.11 to 7.77 μM

Structural Characterization of Kadcoccinin A: A Sesquiterpenoid with a Tricyclo[4.4.0.0^3,10]decane Scaffold from <i>Kadsura coccinea</i>

Kadcoccinin A (<b>1</b>), a cage-like sesquiterpenoid possessing a tricyclo­[4.4.0.0^3,10]­decane scaffold, and the biosynthetically related kadcoccinin B (<b>2</b>) were isolated from the stems of <i>Kadsura coccinea</i>. Their structures and absolute configurations were determined from extensive spectroscopic analysis and quantum chemical calculations. Additionally, their cytotoxic and antifungal effects were initially evaluated, and a plausible biosynthetic pathway was proposed

LC–UV-Guided Isolation and Structure Determination of Lancolide E: A Nortriterpenoid with a Tetracyclo[5.4.0.0^2,4.0^3,7]undecane-Bridged System from a “Talented” <i>Schisandra</i> Plant

Lancolide E (<b>1</b>) featuring a complex tetracyclo­[5.4.0.0^2,4.0^3,7]­undecane-bridged system that is constructed by an eight-, a three-, and two five-membered carbon rings in a sterically congested region was obtained in trace amounts from a “talented” schinortriterpenoid producer <i>Schisandra lancifolia</i>. Its structure was fully characterized by combining 2D NMR spectroscopy, theoretical calculations, and X-ray diffraction analysis. The biogenetic pathway of <b>1</b> was proposed to involve a Prins cyclization

Chemical constituents from <i>Piper wallichii</i>

<div><p>Fifteen known compounds including four triterpenoids (<b>1</b>–<b>4</b>), one sterol (<b>5</b>), one diketopiperazine alkaloid (<b>6</b>) and nine phenolics (<b>7</b>–<b>15</b>) were isolated from the stems of <i>Piper wallichii</i>. Their structures were elucidated by means of spectroscopic analysis, and acidic hydrolysis in case of the 2-oxo-3β,19α,23-trihydroxyurs-12-en-28-oic acid β-D-glucopyranosyl ester (<b>1</b>). The structure of compound <b>1</b> was fully assigned by 1D and 2D NMR experiments for the first time. All isolates were tested for their antibacterial, antifungal, anti-inflammatory and antiplatelet aggregation bioactivities.</p></div

Schilancitrilactones A–C: Three Unique Nortriterpenoids from Schisandra lancifolia

Three unique nortriterpenoids, schilancitrilactones A–C (<b>1</b>–<b>3</b>), were isolated from the stems of Schisandra lancifolia. Compound <b>1</b> possesses a 5/5/7/5/5/5-fused hexacyclic ring system with a C₂₉ backbone, while <b>2</b> and <b>3</b> feature a C₂₇ skeleton with a 5/7/5/5/5-fused pentacyclic ring system. Their absolute stereochemistries were established by CD and single-crystal X-ray diffraction experiments. Compound <b>3</b> showed anti-HIV-1 activity with an EC₅₀ value of 27.54 μg/mL, and <b>1</b> exhibited antifeedant activity at 15.73 μg/cm²