Methamphetamine promotes a-tubulin deacetylation in endothelial cells: The protective role of acetyl-L-carnitine

Methamphetamine (METH) is a powerful psychostimulant drug used worldwide for its reinforcing properties. In addition to the classic long-lasting monoaminergic-disrupting effects extensively described in the literature, METH has been consistently reported to increase blood brain barrier (BBB) permeability, both in vivo and in vitro, as a result of tight junction and cytoskeleton disarrangement. Microtubules play a critical role in cell stability, which relies on post-translational modifications such as a-tubulin acetylation. As there is evidence that psychostimulants drugs modulate the expression of histone deacetylases (HDACs), we hypothesized that in endothelial cells METH-mediation of cytoplasmatic HDAC6 activity could affect tubulin acetylation and further contribute to BBB dysfunction. To validate our hypothesis, we exposed the bEnd.3 endothelial cells to increasing doses of METH and verified that itleads to an extensivea-tubulin deacetylation mediated by HDACs activation. Furthermore, since we recently reported that acetyl-L-carnitine (ALC), a natural occurring compound, prevents BBB structural loss in a context of METH exposure, we reasoned that ALC could also preserve the acetylation of microtubules under METH action. The present results confirm that ALC is able to prevent METH-induced deacetylation providing effective protection on microtubule acetylation. Although further investigation is still needed, HDACs regulation may become a new therapeutic target for ALC

Lista de encabezamientos de materia de la Biblioteca del Congreso de los Estados Unidos características generales

The article describes the historical aspects and principles of the Library of Congress Subject Headings (LCSH). It shows their several formats and features adopted by their subject headings, its several subdivisions and syndetic structure. It also provides the citation order of subject headings and a Bilindex description, a list of bilingual Spanish-English subject headings equivalent to LCSH

Development and evaluation of a systemic assessment framework in organic chemistry

The Systemic Assessment Questions (SAQs) is an assessment scheme proposed in the Systemic Approach to Teaching and Learning (SATL)  teaching model, aiming to a more effective evaluation of the systemic oriented objectives articulated by this model. The goal of a research project carried out in our department for the past five years is the development and evaluation of a systemic assessment framework based on SAQs for the high school organic chemistry. We initially focused on the potential of the SAQ scheme as well as its characteristics required to achieve in  capturing aspects of students’ meaningful understanding. It was found thatSAQs’ task format, diagrams’ complexity, and cognitive demands play a significant role for this scheme in order to efficiently assess meaningful understanding of organic reactions. Based on these results, the SAQ scheme was then further developed and evaluated in various organic chemistry topics. Currently, a systemic assessment orientation was also adopted by focusing on systems thinking assessment. The SAQ scheme was found to be a valuable strategy for assessing meaningful   understanding, as well as systems thinking in organic chemistry. A significant association was observed between students’ performance on SAQs and on objective items designed for assessing meaningful  understanding of organic chemistry concepts. This association indicates that the students’ systems thinking level developed in organic  chemistry is strongly related with a deeper understanding of the relevant science concepts. [AJCE 4(2), Special Issue, May 2014

Development and Validation of a Parameter-Free Model Chemistry for the Computation of Reliable Reaction Rates

A recently developed model chemistry (jun-Cheap) has been slightly modified and proposed as an effective, reliable, and parameter-free scheme for the computation of accurate reaction rates with special reference to astrochemical and atmospheric processes. Benchmarks with different sets of state-of-the-art energy barriers spanning a wide range of values show that, in the absence of strong multireference contributions, the proposed model outperforms the most well-known model chemistries, reaching a subchemical accuracy without any empirical parameter and with affordable computer times. Some test cases show that geometries, energy barriers, zero point energies, and thermal contributions computed at this level can be used in the framework of the master equation approach based on the ab initio transition-state theory for obtaining accurate reaction rates.A recently developed model chemistry (jun-Cheap) has been slightly modified and proposed as an effective, reliable, and parameter-free scheme for the computation of accurate reaction rates with special reference to astrochemical and atmospheric processes. Benchmarks with different sets of state-of-the-art energy barriers spanning a wide range of values show that, in the absence of strong multireference contributions, the proposed model outperforms the most well-known model chemistries, reaching a subchemical accuracy without any empirical parameter and with affordable computer times. Some test cases show that geometries, energy barriers, zero point energies, and thermal contributions computed at this level can be used in the framework of the master equation approach based on the ab initio transition-state theory for obtaining accurate reaction rates

The disputes surrounding RDA configuration and arrangement: Discussions and deliberations about the drafts issued between 2004 and 2008

El artículo presenta la investigación, enmarcada en una tesis de maestría, que trata con la  pugna sobre la estructura, el diseño y el contenido de los diferentes borradores de Resource Description and Access (RDA) publicados entre 2004 y 2008, en el contexto de las deliberaciones y las discusiones generadas por diferentes organizaciones internacionales reunidas por el Joint Steering Committee for Development of RDA (JSC). Se enumeran los apartados vinculados con el problema de investigación, el marco teórico y la hipótesis, el objeto y los objetivos de la investigación, Se describe la metodología de investigación basada en los postulados teóricos de Pierre Bourdieu. Se muestran los principales resultados y hallazgos del estudio, a partir del análisis de los comentarios de diferentes organizaciones que participan del debate sobre los borradores de RDA y de las respuestas de bibliotecarios argentinos a una encuesta. Las conclusiones a las que arriba la investigación examinan los modelos conceptuales en el ordenamiento de RDA, la injerencia de FRBR en las relaciones de RDA y el vínculo entre catalogación y metadatos, junto con una perspectiva actual del campo del control bibliográfico.The article presents an investigation belonging to a master degree. The study deals with the dispute about structure, design and content in Resource Description and Access (RDA) drafts versions issued between 2004 and 2008, during delibertations and discussions accomplished by different organizations gathered by Joint Steering Committee for Development of RDA (JSC). The work enumerates a research problem, a theory framework, a hypothesis, an object and objectives.  It shows the main study results and findings from the comments analysis of the organizations that participate in RDA drafts discussions and the Argentine librarians’ answers to a survey. The research conclusions examine the conceptual models in RDA arrangement, FRBR interference in RDA relations and a link between cataloging and metadata, along with an actual perspective about bibliographic control field

Kinetics and thermodynamics of the hydroxylation products in the photodegradation of the herbicide Metolachlor

Electronic structure calculations have been performed to determine the thermochemistry and kinetics of the reaction between OH and the radicals of the S enantiomer of the herbicide Metolachlor, 2-chloro-N-(2-methyl-6-ethylphenyl)-N(2-methoxy-1-methylethyl) acetamide (MC), produced by photoinduced breaking of the C–Cl bond. Both density functional and ab initio composite methods were employed to calculate the structure of reactants, intermediates, transition states and products, in gas phase and in aqueous solution. The expected relative abundance of each product was calculated and compared to the experimentally observed concentrations. It is shown that a combination of thermodynamic and kinetic characteristics interplay to produce the expected theoretical abundances, which turn out to be in agreement with the experimentally observed distribution of products

Accurate Quantum Chemical Spectroscopic Characterization of Glycolic Acid: A Route Toward its Astrophysical Detection

The first step to shed light on the abiotic synthesis of biochemical building blocks, and their further evolution toward biological systems, is the detection of the relevant species in astronomical environments, including earthlike planets. To this end, the species of interest need to be accurately characterized from structural, energetic, and spectroscopic viewpoints. This task is particularly challenging when dealing with flexible systems, whose spectroscopic signature is ruled by the interplay of small- and large-amplitude motions (SAMs and LAMs, respectively) and is further tuned by the conformational equilibrium. In such instances, quantum chemical (QC) calculations represent an invaluable tool for assisting the interpretation of laboratory measurements or even observations. In the present work, the role of QC results is illustrated with reference to glycolic acid (CH2OHCOOH), a molecule involved in photosynthesis and plant respiration and a precursor of oxalate in humans, which has been detected in the Murchison meteorite but not yet in the interstellar medium or in planetary atmospheres. In particular, the equilibrium structure of the lowest-energy conformer is derived by employing the so-called semiexperimental approach. Then, accurate yet cost-effective QC calculations relying on composite post-Hartree–Fock schemes and hybrid coupled-cluster/density functional theory approaches are used to predict the structural and ro-vibrational spectroscopic properties of the different conformers within the framework of the second-order vibrational perturbation theory. A purposely tailored discrete variable representation anharmonic approach is used to treat the LAMs related to internal rotations. The computed spectroscopic data, particularly those in the infrared region, complement the available experimental investigations, thus enhancing the possibility of an astronomical detection of this molecule