954 resultados para Encima LDH


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El siguiente documento tiene como finalidad enseñarle al lector cómo una de las constructoras líderes del sector en Colombia, Constructora Colpatria, se ha visto involucrada en la toma de ciertas decisiones estratégicas, las cuales han llevado a la compañía a conseguir una diversificación en diferentes áreas de negocio y un proceso de internacionalización en países como México y Perú. La principal razón de estos cambios que ha tenido la Constructora Colpatria, es básicamente un problema que surge hace un poco más de 20 años. Hacia la década de los 90 se presentó una crisis financiera que tuvo su origen en el mercado hipotecario, desde ese entonces, el sector construcción se ha visto involucrado en un fenómeno que es comúnmente conocido como burbuja inmobiliaria, este término se refiere a la subida injustificada y exagerada de los precios de los inmuebles o de los bienes raíces muy por encima del precio real de venta. En el contexto de estrategia, el proyecto se va a encaminar por el lado de las decisiones y el manejo que se le ha dado por parte de la empresa a la problemática que ha presentado el sector construcción a lo largo de los últimos años. Por medio de diferentes métodos de investigación, que serán explicados más adelante, se quiere evaluar y conocer como esta empresa ha logrado conseguir un alto nivel de competitividad y cómo se ha posicionado en los primeros puestos en el sector construcción en Colombia.

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El papel de la cultura en la globalización es de suma importancia, sin embargo, no se le ha dado el espacio que amerita. La cultura envuelve los símbolos de interacción y comprensión de la realidad que los seres humanos utilizan para la cotidianidad. Las culturas muestran entre sí diferencias considerables, que nacen a partir de los diversos símbolos de interacción que pueden existir en una sociedad. Con la globalización, los seres humanos se ven expuestos a un rango sumamente amplio de nuevos símbolos de interacción, en algunas formas inclusive contrarios a los propios. Es en este proceso donde se presentan flujos de intercambio o imposición de simbolismos de unas culturas con respecto a otras, cuando una cultura toma nuevos simbolismos, existe un cambio en su interpretación del mundo y en su actuar, llamado aculturación. La cultura occidental ha sido la que más simbolismos ha impuesto a otras, ya sea por formas pacíficas o por el uso de la fuerza, y por ende la que se ha situado por encima de las otras.Palabras Claves: Globalización, cultura, símbolos, interaccionismo, aculturación, identidad, imposición.

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 En el presente trabajo se aborda de manera sucinta, el estado de la cartografía aplicada a los estudios medioambientales en América Latina, con énfasis en lo que  deberá constituirse, en opinión del autor, en un nuevo paradigma en los estudios geográficos y medioambientales: la Cartografía Geográfica.La situación de América Latina en este nuevo siglo continúa las sombrías proyecciones emitidas a finales del siglo XX: Un crecimiento de la población por encima de la media mundial, cuyo número desde el año 2005 rebasa los 560 millones de individuos, un creciente proceso de urbanización,  con una población urbana cuya concentración crece de manera alarmante y que agrupa algunas de las ciudades más pobladas del planeta, la extensión y profundización del nivel de pobreza extrema, la existencia de ínfimos niveles de educación, empleo insuficiente, desnutrición, falta de servicios médicos, analfabetismo, violencia, hacinamiento de la población en barrios insalubres, contaminación creciente en las ciudades, deforestación, empobrecimiento de las grandes masas de campesinos, descapitalización y atraso tecnológico, realidades que configuran un panorama que permite entrever un futuro casi inevitable de crisis económica y social en los próximos años.El medio ambiente se concibe como “el sistema de elementos abióticos, bióticos y socioeconómicos con los que el hombre entra en contacto, modificándolos y utilizándolos para la  satisfacción de sus necesidades”. (Arcia y otros, 1994).La geografía es la ciencia que trata de las relaciones que se establecen entre la naturaleza y la sociedad y de su desarrollo y desenvolvimiento en el espacio y en el tiempo. Por estas razones, está en condiciones de aportar elementos importantes al estudio de los problemas del medio ambiente y de la utilización racional de los recursos y además, en aspectos tales como los relativos a la  determinación de los límites de las unidades medioambientales, a la ubicación espacial de los mecanismos de intercambio de sustancia y energía que ocurren en los ecosistemas y a las propuestas  adecuadas para  el ordenamiento de los territorios. 

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Sin duda alguna, el debate sobre el derecho penal del enemigo es una cuestión que está revolucio­nando el mundo del derecho, en general, y el derecho internacional en particular. Es un debate de actualidad que está llamando la atención de la comunidad académica, en tanto se plantea y se avizora un problema de fondo, en cuanto a la efectiva protección de los derechos humanos, por encima de un discurso de seguridad, que se viene planteando como eje central en la comunidad internacional, en la lucha contra el terrorismo y como estrategia jurídico-política al interior de Estados que dicen llamarse democráticos. Esta situación está revolucionando desde cualquier punto de vista la concepción tradicional del derecho, violentando flagrantemente la dignidad humana como eje central del Estado Social de Derecho, al poner en práctica lo que Jakobs denomina “dere­cho penal del enemigo”, práctica que también se viene fortaleciendo y traspasándose del ejercicio del ius puniendi de los Estados, como manifestación de soberanía, al derecho penal internacional.Abstract Without any doubt, the debate about the penal right of the enemy is a question that is revolutionizing the world of law in a general level, and international right in particular. It is a current debate that is drawing the attention of the academic community, as it poses as a basic problem: the effective protection of the human rights, over a security discourse which is presented as central in the international community in the fight against terrorism, and as a legal-political strategy to the interior of the so called democratic States. This situation is revolutionizing, from different points of view, the traditional conception of law, flagrantly violenting the human dignity as the central axis of the Social State of Right, putting in practice what Jakobs denominates “Criminal law for the enemy”. This practice is being fortified and transferring from the exercise of ius puniendi of the States, as manifestation of sovereignty, to the international penal right.

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Synthetic lethality represents an anticancer strategy that targets tumor specific gene defects. One of the most studied application is the use of PARP inhibitors (e.g. olaparib) in BRCA1/2-less cancer cells. In BRCA2-defective tumors, olaparib (OLA) inhibits DNA single-strand break repair, while BRCA2 mutations hamper homologous recombination (HR) repair. The simultaneous impairment of those pathways leads BRCA-less cells to death by synthetic lethality. The projects described in this thesis were aimed at extending the use of OLA in cancer cells that do not carry a mutation in BRCA2 by combining this drug with compounds that could mimic a BRCA-less environment via HR inhibition. We demonstrated the effectiveness of our “fully small-molecule induced synthetic lethality” by using two different approaches. In the direct approach (Project A), we identified a series of neo-synthesized compounds (named RAD51-BRCA2 disruptors) that mimic BRCA2 mutations by disrupting the RAD51-BRCA2 interaction and thus the HR pathway. Compound ARN 24089 inhibited HR in human pancreatic adenocarcinoma cell line and triggered synthetic lethality by synergizing with OLA. Interestingly, the observed synthetic lethality was triggered by tackling two biochemically different mechanisms: enzyme inhibition (PARP) and protein-protein disruption (RAD51-BRCA2). In the indirect approach (Project B), we inhibited HR by interfering with the cellular metabolism through inhibition of LDH activity. The obtained data suggest an LDH-mediated control on HR that can be exerted by regulating either the energy supply needed to this repair mechanism or the expression level of genes involved in DNA repair. LDH inhibition also succeeded in increasing the efficiency of OLA in BRCA-proficient cell lines. Although preliminary, these results highlight a complex relationship between metabolic reactions and the control of DNA integrity. Both the described projects proved that our “fully small-molecule-induced synthetic lethality” approach could be an innovative approach to unmet oncological needs.

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Layered Double hydroxides (LDHs) have been widely studied for their plethora of fascinating features and applications. The potentiostatic electrodeposition of LDHs has been extensively applied in the literature as a fast and direct method to substitute classical chemical routes. However, it does not usually allow for a fine control of the M(II)/M(III) ratio in the synthesized material and it is not suitable for large anions intercalation. Therefore, in this work a novel protocol has been proposed with the aim to overcome all these constraints using a method based on potentiodynamic synthesis. LDHs of controlled composition were prepared using different molar ratios of the trivalent to bivalent cations in the electrolytic solution ranging from 1:1 to 1:4. Moreover, we were able to produce electrochemically LDHs intercalated with carbon nanomaterials for the first time. A one-step procedure which contemporaneously allows for the Ni/Al-LDH synthesis, the reduction of graphene oxide (GO) and its intercalation inside the structure has been developed. The synthesised materials have been applied in several fields of interest. First of all, LDHs with a ratio 3:1 were exploited, and displayed good performances as catalysts for 5-(hydroxymethyl)furfural electro-oxidation, thus suggesting to carry out further investigation for applications in the field of industrial catalysis. The same materials, but with different metals ratios, were tested as catalysts for Oxygen Evolution Reaction, obtaining results comparable to LDHs synthesised by the classical co-precipitation method and also a better activity with respect to LDHs obtained by the potentiostatic approach. The composite material based on LDH and reduced graphene oxide was employed to fabricate a cathode of a hybrid supercapacitor coupled with an activated carbon anode. We can thus conclude that, to date, the potentiodynamic method has the greatest potential for the rapid synthesis of reproducible films of Co and Ni-based LDHs with controlled composition.

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In questo lavoro, sono state valutate le prestazioni di quattro tipi di LDH (Co/Al e Co/Fe entrambe con e senza GO nella soluzione di elettrodeposizione) per l'applicazione in stoccaggio di energia, andando a confrontare le capacità specifiche calcolate da voltammetrie cicliche e curve galvanostatiche di carica/scarica. I risultati di tali analisi hanno mostrato come l’LDH a base di Al sia più adatto all’applicazione di accumulo di energia, rispetto a quello con il Fe. Ulteriori caratterizzazioni, come l’XRD ed il SEM accoppiato con l'EDX, hanno confermato la maggior applicabilità dei LDH di Co/Al rispetto a quelli di Co/Fe, in quanto i primi presentano: una struttura più cristallina, una morfologia più uniforme ed un’intercalazione dell’ERGO migliore. Dopo la fase di scelta dell’LDH più performante ci si è dedicati alla caratterizzazione di un capacitore ibrido operante in fase liquida. Concluse le analisi, si è notato come l’ERGO porti all'aumento delle prestazioni del sistema (risultato in linea con quello riscontrato tramite lo studio degli LDH come componenti catodici singoli). Grazie allo studio delle performance a lungo termine è stato possibile verificare come l’ERGO aumenti la stabilità del sistema quando si sottopone quest’ultimo a stress protratto nel tempo. Successivamente, si è proseguito con lo studio di un capacitore ibrido operante in fase solida. Come nel caso del sistema in fase liquida, si è riscontrato un aumento di performance dovuto alla presenza di ERGO nella struttura finale degli LDH.

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This Ph.D. thesis concerns the synthesis of nanostructured Cu-containing materials to be used as electrode modifiers for the CO2 electroreduction in aqueous phase and the evaluation of their catalytic performances. Inspired by the fascinating concept of the artificial photosynthesis-oriented systems, several catalytic layers were electrochemically loaded on carbonaceous gas diffusion membranes, i.e., 3D structures that allow the design of eco-friendly materials for applications in green carbon recycling processes. In particular, early studies on Cu(I-II)-Cu(0) nanostructured materials were carried out to produce films on 4 cm2 sized supports by means of a fast and low-cost electrochemical procedure. Besides, through a screening of potentials, it was possible to find out a selective value for the CH3COOH production at -0.4 V vs RHE with a maximum productivity (1h reaction), ensured by the presence of the Cu+/Cu0 active redox couple (0.31 mmol gcat-1 h-1). On the basis of these results, further optimisations of the electrocatalyst chemical composition were carried out with the aim of (i) facilitating the interaction with CO2, (ii) increasing the dispersion of the catalytic active phase, and (iii) enhancing the CH3COOH productivity. To this aim, novel electrocatalysts based on layered double hydroxides (LDHs) were optimised, having as a final goal the formation of a new Cu2O-Cu0 based electrocatalyst derived from electrochemically achieved CuMgAl LDHs, subjected to calcination and reduction processes. The as-obtained electrocatalysts were tested for the selective production of CH3COOH and unprecedented results were obtained with the pristine CuMgAl LDH (2.0 mmol gcat-1 h-1). Additional characterisations of such an electrocatalyst have highlighted the possibility to achieve a ternary LDH in intimate contact with Cu2O-Cu0 species starting from the electrochemical deposition. The presence of these species, along with an alkaline environment on the electrode surface, were essential to preserve the selectivity towards the desired product, as confirmed by further operando studies.

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The treatment of metastatic castration-resistant prostate cancer (mCRPC) is currently characterized by several drugs with different mechanisms of action, such as new generation hormonal agents (abiraterone, enzalutamide), chemotherapy (docetaxel, cabazitaxel), PARP inhibitors (olaparib) and radiometabolic therapies (radium-223, LuPSMA). There is an urgent need to identify biomarkers to guide personalized therapy in mCRPC. In recent years, the status of androgen receptor (AR) gene detected in liquid biopsy has been associated with outcomes in patients treated with abiraterone or enzalutamide. More recently, plasma tumor DNA (ptDNA) and its changes during treatment have been identified as early indicators of response to anticancer treatments. Recent works also suggested a potential role of tumor-related metabolic parameters of 18Fluoro-Choline Positron Emission Tomography (F18CH-PET)-computed tomography (CT) as a prognostic tool in mCRCP. Other clinical features, such as the presence of visceral metastases, have been correlated with outcome in mCRPC patients. Recent studies conducted by our research group have designed and validated a prognostic model based on the combination of molecular characteristics (ptDNA levels), metabolic features found in basal FCH PET scans (metabolic tumor volume values, MTV), clinical parameters (absence or presence of visceral metastases), and laboratory tests (serum lactate dehydrogenase levels, LDH). Within this PhD project, 30 patients affected by mCRPC, pre-treated with abiraterone or enzalutamide, candidate for taxane-based treatments (docetaxel or cabazitaxel), have been prospectively evaluated. The prognostic model previously described was applied to this population, to interrogate its prognostic power in a more advanced cohort of patients, resulting in a further external validation of the tool.