861 resultados para Meso-tetrakis porphyrins


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En un intento de describir procesos de construcción de espacios agrícolas locales, sin duda debe hacerse  el esfuerzo por considerar una multiplicidad de actores y niveles espaciales observables en una interacción constante entre escalas diversas, mismas que van desde lo local y lo regional, hasta llegar a lo meso y nacional. Ante dicha complejidad, resulta relevante considerar las variadas articulaciones entre actores cuyo radio de acción puede tener su origen en alguno de los niveles escalares señalados, de acuerdo con el periodo histórico considerado. A ese respecto quizá el ejemplo del desarrollo de la irrigación en una pequeña región ubicada en el occidente de México, pueda ilustrar la interacción entre actores sociales, algunos ubicados en lo local regional (campesinos e instituciones locales) y otros en lo meso y nacional (funcionarios de los gobiernos estatal y nacional).  El objetivo del presente trabajo es dar cuenta del proceso de construcción de espacios agrícolas locales comprendidos en una pequeña región del Occidente de México.  Un aspecto concluyente a señalar, es que el Estado no es un ente monolítico ni los actores locales y regionales son meros ejecutores de decisiones externas a lo local, sino más bien éstos últimos buscan negociar según sus intereses.

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A fianco ai metodi più tradizionali, fin ora utilizzati, le tecnologie additive hanno subito negli ultimi anni una notevole evoluzione nella produzione di componenti. Esse permettono un ampio di range di applicazioni utilizzando materiali differenti in base al settore di applicazione. In particolare, la stampa 3D FDM (Fused Deposition Modeling) rappresenta uno dei processi tecnologici additivi più diffusi ed economicamente più competitivi. Gli attuali metodi di analisi agli elementi finiti (FEM) e le tecnologie CAE (Computer-Aided Engineering) non sono in grado di studiare modelli 3D di componenti stampati, dal momento che il risultato finale dipende dai parametri di processo e ambientali. Per questo motivo, è necessario uno studio approfondito della meso struttura del componente stampato per estendere l’analisi FEM anche a questa tipologia di componenti. Lo scopo del lavoro proposto è di creare un elemento omogeneo che rappresenti accuratamente il comportamento di un componente realizzato in stampa 3D FDM, questo avviene attraverso la definizione e l’analisi di un volume rappresentativo (RVE). Attraverso la tecnica dell’omogeneizzazione, il volume definito riassume le principali caratteristiche meccaniche della struttura stampata, permettendo nuove analisi e ottimizzazioni. Questo approccio permette di realizzare delle analisi FEM sui componenti da stampare e di predire le proprietà meccaniche dei componenti a partire da determinati parametri di stampa, permettendo così alla tecnologia FDM di diventare sempre di più uno dei principali processi industriali a basso costo.

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Malignant Pleural Mesothelioma (MPM) is a very aggressive cancer whose incidence is growing worldwide. MPM escapes the classical models of carcinogenesis and lacks a distinctive genetic fingerprint, keeping obscure the molecular events that lead to tumorigenesis. This severely impacts on the limited therapeutic options and on the lack of specific biomarkers, concurring to make MPM one of the deadliest cancers. Here we combined a functional genome-wide loss of function CRISPR/Cas9 screening with patients’ transcriptomic and clinical data, to identify genes essential for MPM progression. Besides, we explored the role of non-coding RNAs to MPM progression by analysing gene expression profiles and clinical data from the MESO-TCGA dataset. We identified TRIM28 and the lncRNA LINC00941 as new vulnerabilities of MPM, associated with disease aggressiveness and bad outcome of patients. TRIM28 is a multi-domain protein involved in many processes, including transcription regulation. We showed that TRIM28 silencing impairs MPM cells’ growth and clonogenicity by blocking cells in mitosis. RNA-seq profiling showed that TRIM28 loss abolished the expression of major mitotic players. Our data suggest that TRIM28 is part of the B-MYB/FOXM1-MuvB complex that specifically drives the activation of mitotic genes, keeping the time of mitosis. In parallel, we found LINC00941 as strongly associated with reduced survival probability in MPM patients. LINC00941 KD profoundly reduced MPM cells’ growth, migration and invasion. This is accompanied by changes in morphology, cytoskeleton organization and cell-cell adhesion properties. RNA-seq profiling showed that LINC00941 KD impacts crucial functions of MPM, including HIF1α signalling. Collectively these data provided new insights into MPM biology and demonstrated that the integration of functional screening with patients’ clinical data is a powerful tool to highlight new non-genetic cancer dependencies that associate to a bad outcome in vivo, paving the way to new MPM-oriented targeted strategies and prognostic tools to improve patients risk-based stratification.

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To change unadapted water governing systems, and water users’ traditional conducts in line with climate change, understanding of systems’ structures and users’ behaviors is necessary. To this aim, comprehensive and pragmatic research was designed and implemented in the Urmia Lake Basin where due to the severe droughts, and human-made influences, especially through the agricultural development, the lake has been shrunken drastically. To analyze the water governance and conservation issues in the basin, an innovative framework was developed based on mathematical physics concepts and pro-environmental behavior theories. Accordingly, in system level (macro/meso), the problem of fit of the early-shaped water governing system associating with the function of “political-security” and “political-economic” factors in the basin was identified through mean-field models. Furthermore, the effect of a “political-environmental” factor, the Urmia Lake Restoration Program (ULRP), on reforming the system structure and hence its fit was assessed. The analysis results revealed that by revising the provincial boundaries (horizontal alternation) for the entity of Kurdistan province to permit that interact with the headquarter of West Azerbaijan province for its water demand-supply initiatives, the system fit can increase. Also, the constitution of the ULRP (vertical arrangement) not only could increase the structural fit of the water governing system to the basin, but also significantly could enhance the system fit through its water-saving policy. Besides, in individual level (micro), the governing factors of water conservation behavior of the major users/farmers were identified through rational and moral socio-psychological models. In rational approach, incorporating PMT and TPB, the SEM results demonstrated that “Perceived Vulnerability”, “Self-Efficacy”, “Response Efficacy”, “Response Cost”, “Subjective Norms” and “Institutional Trust” significantly affect the water-saving intention/behavior. Likewise, NAM based analysis as a moral approach, uncovered the significant effects of “Awareness of Consequences”, “Appraisal of Responsibility”, “Personal Norms” as well as “Place Attachment” and “Emotions” on water-saving intention.

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In this work, two different protocols for the synthesis of Nb2O5-SiO2 with a sol-gel route in which supercritical carbon dioxide was used as solvent have been developed. The tailored design of the reactor allowed the reactants to come into contact only when supercritical CO2 is present, and the high-throughput experimentation scCO2 unit allowed the screening of synthetic parameters, that led to a Nb2O5 incorporation into the silica matrix of 2.5 wt%. N2-physisorption revealed high surface areas and the presence of meso- and micropores. XRD allowed to demonstrate the amorphous character of these materials. SEM-EDX proved the excellent dispersion of Nb2O5 into the silica matrix. These materials were tested in the epoxidation of cyclooctene with hydrogen peroxide, which is considered an environmentally friendly oxidant. The catalysts were virtually inactive in an organic, polar, aprotic solvent (1,4-dioxane). However, the most active scCO2 Nb2O5-SiO2 catalyst achieved a cyclooctene conversion of 44% with a selectivity of 88% towards the epoxide when tested in ethanol. Catalytic tests on cyclohexene revealed the presence of the epoxide, which is remarkable, considering that this substrate is easily oxidised to the diol. The behaviour in protic and aprotic solvents is compared to that of TS-1.

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This thesis is focused on the viscoelastic behavior of macro-synthetic fiber-reinforced concrete (MSFRC) with polypropylene studied numerically when subjected to temperature variations (-30 oC to +60 oC). LDPM (lattice discrete particle model), a meso-scale model for heterogeneous composites, is used. To reproduce the MSFRC structural behavior, an extended version of LDPM that includes fiber effects through fiber-concrete interface micromechanics, called LDPM-F, is applied. Model calibration is performed based on three-point bending, cube, and cylinder test for plain concrete and MSFRC. This is followed by a comprehensive literature study on the variation of mechanical properties with temperature for individual fibers and plain concrete. This literature study and past experimental test results constitute inputs for final numerical simulations. The numerical response of MSFRC three-point bending test is replicated and compared with the previously conducted experimental test results; finally, the conclusions were drawn. LDPM numerical model is successfully calibrated using experimental responses on plain concrete. Fiber-concrete interface micro-mechanical parameters are subsequently fixed and LDPM-F models are calibrated based on MSFRC three-point bending test at room temperature. Number of fibers contributing crack bridging mechanism is computed and found to be in good agreement with experimental counts. Temperature variations model for individual constituents of MSFRC, fibers and plain concrete, are implemented in LDPM-F. The model is validated for MSFRC three-point bending stress-CMOD (crack mouth opening) response reproduced at -30 oC, -15 oC, 0 oC, +20 oC, +40 oC and +60 oC. It is found that the model can well describe the temperature variation behavior of MSFRC. At positive temperatures, simulated responses are in good agreement. Slight disagreement in negative regimes suggests an in-depth study on fiber-matrix interface bond behavior with varying temperatures.