Análisis morfométrico 3D de colon aplicado a un abordaje quirúrgico laparoscópico. Estudio cadaver

Objective: The aim of this study is to define the changes that occurred in certain segments of the colons of cadavers after subjecting them to the conditions that are used in laparoscopic surgery of the colon. Methodology: Three cadavers were submitted to abdominal computerized tomography, first with no external, and then after the application of 15 mm of Hg of pneumoperitoneum and 15 degrees Trendelenburg, right or left lateral decubitus. Three-dimensional reconstruction of the images was performed for a morphological descriptive study of the pubic points, superior mesenteric artery, inferior mesenteric artery, hepatic flexure and splenic flexure. Results: A total of 390 measurements were performed, 159 showed changes. The inferior mesenteric artery point modifications were the most strongly related to the other points. The transverse colon – pubic symphysis – descending colon angle depended on the pubic symphysis – descending colon distance, and the transverse colon – inferior mesenteric artery – descending colon angle depended on the inferior mesenteric artery – transverse colon distance. Conclusions: The positional changes of the points studied were related to their attachment to the peritoneum, to the proximity of the neighboring viscera and to their location in the abdomen.Objetivo: El objetivo de este estudio es definir los cambios ocurridos en ciertos segmentos colónicos de cadáveres tras someterlos a una cirugía laparoscópica de colon. Metodología: Tres cadáveres fueron sometidos a tomografía computarizada abdominal, primero sin externa presión, y luego con aplicación de 15 mm Hg de neumoperitoneo y 15 grados Trendelenburg, en decúbito lateral derecho o izquierdo. Se realizó reconstrucción tridimensional de las imágenes para un estudio morfológico descriptivo de los puntos púbicos, arteria mesentérica superior, arteria mesentérica inferior, ángulo hepático y ángulo esplénico. Resultados: Se realizaron un total de 390 mediciones, 159 mostraron cambios. Las modificaciones de los puntos de la arteria mesentérica inferior fueron las más fuertemente relacionadas con los otros puntos. El ángulo del colon transverso – sínfisis púbica – colon descendente dependía de la sínfisis púbica – distancia del colon descendente, y el ángulo del colon transverso – arteria mesentérica inferior – colon descendente de la distancia entre la arteria mesentérica inferior y el colon transverso. Conclusiones: Los cambios posicionales de los puntos estudiados se relacionaron con su inserción al peritoneo, con la proximidad de las vísceras vecinas y con su ubicación en el abdomen

Palladium-Catalyzed Conjugate Addition of Terminal Alkynes to Enones

A practical protocol for the hydroalkynylation of enones using Pd catalysis is reported. The reaction proceeds efficiently with a variety of alkynes as well as with several cyclic and acyclic enones, providing synthetically relevant β-alkynyl ketones in good to excellent yields

Informe sobre la producción científica de Venezuela en revistas iberoamericanas de acceso abierto en redalyc.org, 2005-2011

Objetivo: Proporcionar información sobre el Perfil de Producción Científica de Venezuela en revistas del acervo redalyc.org para el periodo 2005-2011, con el fin de conocer cuáles son tanto las tendencias como el comportamiento de las estrategias de comunicación y de colaboración que registran los artículos producidos por los investigadores venezolanos.Método: Se estudia la producción científica de 800 revistas iberoamericanas de acceso abierto durante 2005-2011, a partir de un modelo de análisis centrado en entidades de producción y comunicación, las cuales permiten generar un Perfil de Producción Científica según los indicadores de: Producción (P), Producción en Colaboración (PC) y Colaboración (C), aplicados a un núcleo de 145,515 artículos científicos que forman parte del acervo redalyc.org.Resultados: La producción científica de Venezuela asciende a 7,394 artículos que corresponden a una aportación de 5.1% sobre el total analizado, de los cuales 23.4% fueron publicados en revistas extranjeras, y donde poco más de la mitad corresponde al área de ciencias sociales (54.2%), seguida de ciencias con 35.3%, mientras que artes y humanidades alcanza 5.3% y multidisciplinaria 5.2%. Las instituciones venezolanas con mayor aporte a la producción científica son la Universidad de Zulia (LUZ), la Universidad Central de Venezuela (UCV) y la Universidad de los Andes (ULA); mientras que 60.7% de los trabajos firmados por autores nacionales se han realizado en colaboración, principalmente de tipo nacional e institucional (61.7%), y donde la participación de autores del extranjero se vincula prioritariamente con México, Colombia, España y Chile, que en conjunto representan el 71.3% de la producción de Venezuela en colaboración con otros países

Phyllanthus emblica

The experimentally observed stereomutation of spiro-1,2-oxaphosphetanes is shown by DFT calculations to proceed through successive M_B2 or M_B4 and M_B3 mechanisms involving two, four, and three Berry pseudorotations at phosphorus, respectively. Oxaphosphetane decomposition takes place in a single step via a polar transition state. The calculated activation parameters for this reaction are in good agreement with those determined experimentally

Directed <i>Ortho</i>-Lithiation of Aminophosphazenes: An Efficient Route to the Stereoselective Synthesis of <i>P</i>‑Chiral Compounds

<i>Ortho</i>-directed lithiation of <i>P</i>,<i>P</i>-diphenylaminophosphazenes followed by electrophilic quench is described as an efficient process for synthesizing <i>P</i>-chiral <i>ortho</i>-functionalized derivatives in high yields and diastereoselectivities. The method allows the tunable preparation of structurally diverse enantiopure <i>P</i>-chiral compounds including phosphinic and phosphinothioic amides, phosphinic esters, phosphine oxides, and <i>o</i>-aminophosphines

Amido Complexes of Iridium with a PNP Pincer Ligand: Reactivity toward Alkynes and Hydroamination Catalysis

The pincer ligand HN­(CH₂CH₂PPh₂)₂ (<b>1</b>; PN<i>H</i>P) reacted with [{Ir­(μ-X)­(cod)}₂] (X = Cl, OMe), affording complexes [<i>fac</i>-(PN<i>H</i>P)­Ir­(cod)]Cl (<b>2</b>) and [<i>fac</i>-(PNP)­Ir­(cod)] (<b>3</b>), respectively. The X-ray molecular structure of <b>2</b> showed that the PNP ligand coordinates in a facial fashion, with the N atom in an axial site and both P atoms coordinated in the equatorial plane. Compound <b>1</b> is able to protonate the hydroxo bridges in the complex [{Ir­(μ-OH)­(coe)₂}₂] forming the new amido complex [<i>mer</i>-(PNP)­Ir­(coe)] (<b>4</b>). Complex <b>4</b> is an extremely air sensitive compound, as confirmed by the isolation of the oxo complex [<i>mer</i>-(PNP)­Ir­(η²-O₂)] (<b>8</b>) from its interaction with air. Protonation of <b>4</b> with HBF₄ afforded the corresponding amino complex [<i>mer</i>-(PN<i>H</i>P)­Ir­(coe)]­BF₄ (<b>5</b>), whose molecular structure enlightened by X-ray crystallography confirmed the PNP ligand to be coordinated in a meridional fashion. The coe ligand in <b>4</b> is tightly bonded to iridium; however, under an atmosphere of ethylene at 60 °C or with acrylonitrile at 70 °C complex <b>4</b> exchanges the olefin, affording compounds [<i>mer</i>-(PNP)­Ir­(η²-C₂H₄)] (<b>6</b>) and [<i>mer</i>-(PNP)­Ir­(η²-C₂H₃CN)] (<b>7</b>), respectively. Interaction of <b>4</b> with alkynes depends on the nature of the substrate; therefore, methyl phenylpropiolate reacted with <b>4</b>, affording the adduct [<i>mer</i>-(PNP)­Ir­(η²-PhCCC­(O)­OMe)] (<b>9</b>), while the parent acetylene undergoes a double C–H activation, affording the Ir­(III) complex [<i>fac</i>-(PN<i>H</i>P)­IrH­(CCH)₂] (<b>10</b>). A DFT theoretical analysis of this transformation supports a metal–ligand cooperation mechanism. The reaction starts by deprotonation of an alkyne moiety by the PNP ligand followed by oxidative addition of the C–H bond to the metal of a second alkyne molecule. Additionally, we have tested complex <b>4</b> as a catalyst for the addition of gaseous ammonia to activated unsaturated substrates. A DFT theoretical analysis disclosed the operative mechanism on these organic transformations, which starts with a nucleophilic attack of ammonia to the bound alkyne, hydrogen migration to the metal, and reductive elimination steps

Exploring the effect of composting technologies on the recovery of hydrocarbon contaminated soil post chemical oxidative treatment

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic pollutants that contaminate large areas. They are mainly released to environment by anthropogenic activities principally due to the petrochemical industry. The low biodegradation rate characteristic of PAHs in aged contaminated soils could be overcome trough the chemical oxidation. In this study, composting with the soil and stimulation with mature compost were the strategies applied in soil microcosms after chemical oxidation with ammonium persulfate in a PAHs chronically contaminated soil. A 29% of PAHs elimination and an increase of their bioavailability were found after chemical oxidation with ammonium persulfate. Due to the oxidative treatment the total bacterial and the gram-positive population PAH dioxygenase genes were significantly reduced and no gram-negative PAHs degraders were detected. The following application of organic amendments produced a higher increase in total bacteria and recovery of the degrading population of GP PAH after one year of treatment, in comparison with the pre-oxidized soil bioremediation, only promoted by irrigation and aeration. Also a significant increase in the content of bioavailable PAHs was observed. However, from both composting strategies only the stimulation with mature compost led to a net PAHs removal. Taking into account the residual dissolved total carbon and humification degree (E4/E6 ratio), it was attributed to the preferential consumption of more easily degradable compounds than hydrocarbons the low removal efficiency observed after one year of treatment. Due to the high bioavailable content of PAH and the residual sulfate, long-term treatments will require careful monitoring to reduce environmental risk

Two-Photon Fluorescence Anisotropy Imaging to Elucidate the Dynamics and the Stability of Immobilized Proteins

Time/spatial-resolved fluorescence determines anisotropy values of supported-fluorescent proteins through different immobilization chemistries, evidencing some of the molecular mechanisms that drive the stabilization of proteins at the interfaces with solid surfaces. Fluorescence anisotropy imaging provides a normalized protein mobility parameter that serves as a guide to study the effect of different immobilization parameters (length and flexibility of the spacer arm and multivalency of the protein–support interaction) on the final stability of the supported proteins. Proteins in a more constrained environment correspond to the most thermostable ones, as was shown by thermal inactivation studies. This work contributes to explain the experimental evidence found with conventional methods based on observable measurements; thus this advanced characterization technique provides reliable molecular information about the immobilized proteins with sub-micrometer spatial resolution. Such information has been very useful for fabricating highly stable heterogeneous biocatalysts with high interest in industrial developments

ITH14001, a CGP37157-Nimodipine Hybrid Designed to Regulate Calcium Homeostasis and Oxidative Stress, Exerts Neuroprotection in Cerebral Ischemia

During brain ischemia, oxygen and glucose deprivation induces calcium overload, extensive oxidative stress, neuroinflammation, and, finally, massive neuronal loss. In the search of a neuroprotective compound to mitigate this neuronal loss, we have designed and synthesized a new multitarget hybrid (ITH14001) directed at the reduction of calcium overload by acting on two regulators of calcium homeostasis; the mitochondrial Na⁺/Ca²⁺ exchanger (mNCX) and L-type voltage dependent calcium channels (VDCCs). This compound is a hybrid of CGP37157 (mNCX inhibitor) and nimodipine (L-type VDCCs blocker), and its pharmacological evaluation revealed a moderate ability to selectively inhibit both targets. These activities conferred concentration-dependent neuroprotection in two models of Ca²⁺ overload, such as toxicity induced by high K⁺ in the SH-SY5Y cell line (60% protection at 30 μM) and veratridine in hippocampal slices (26% protection at 10 μM). It also showed neuroprotective effect against oxidative stress, an activity related to its nitrogen radical scavenger effect and moderate induction of the Nrf2-ARE pathway. Its Nrf2 induction capability was confirmed by the increase of the expression of the antioxidant and anti-inflammatory enzyme heme-oxygenase I (3-fold increase). In addition, the multitarget profile of ITH14001 led to anti-inflammatory properties, shown by the reduction of nitrites production induced by lipopolysaccharide in glial cultures. Finally, it showed protective effect in two acute models of cerebral ischemia in hippocampal slices, excitotoxicity induced by glutamate (31% protection at 10 μM) and oxygen and glucose deprivation (76% protection at 10 μM), reducing oxidative stress and iNOS deleterious induction. In conclusion, our hybrid derivative showed improved neuroprotective properties when compared to its parent compounds CGP37157 and nimodipine