997 resultados para C .net
Resumo:
Projecte de recerca elaborat a partir duna estada a la University of Nottingham, Gran Bretanya, entre mar i abril del 2007. Aquest treball sha centrat en laplicaci de compostos derivats de la D-(+)-glucosa, de la D-(+)-fructosa i la D-galactosa com a lligands de catalitzadors homogenis quirals en dos reaccions asimtriques: addici 1,2 a aldehids catalitzada per nquel i addici 1,4 conjugada catalitzada per coure.(veure figura adjunta al final del document). En primer lloc, sha estudiat laplicaci dels compostos L1-L6 a les reaccions daddici 1,2 a aldehids catalitzades per nquel. Sha observat que la selectivitat del procs depn principalment del grup funcional unit a lesquelet del lligand, de les propietats estriques del substituent en la funci oxazolina i de lestructura del substrat. Sha obtingut fins a un 59% dexcs enantiomric utilitzant el precursor de catalitzador que cont el lligand L3a. En segon lloc, aquest treball descriu laplicaci de les tres famlies de compostos (L1-L11) com a lligands en la reacci daddici 1,4 catalitzada per coure de compostos organometllics a diferents enones amb diferents propietats estriques. Ls de les llibreries de compostos fosfit-oxazolina (L1-L5) i fosfit-fosforamidit (L6) han proporcionat bones enantioselectivitats (fins a 80%) en laddici de reactius de trialquilalumini a diferents enones. En canvi, la llibreria de compostos monofosfit (L7-L11) ha mostrat bones activitats per enantioselectivitats fins a 57%.
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Estudi realitzat a partir duna estada a la School of Chemistry de la University of Bristol, Gran Bretanya, entre 2006 i 2008. La reacci dactivaci del pre-catalitzador CH3-Fe(P(iPr)2CH2)3B-Ph, que es dna en presncia de H2 i P(CH3)3, s una reacci spin-prohibida ja que els reactius i els productes tenen diferents estat despn en el seu estat fonamental: el pre-catalitzador s quintet, mentre que el producte format desprs de leliminaci de met, PMe3(H3)-Fe[(P(iPr)2CH2)3B-Ph, s singlet. Un dels intermedis daquesta reacci s despecial inters ja que catalitza la hidrogenaci dolefines. Intermedi que experimentalment sha proposat com a H-Fe[(P(iPr)2CH2)3B-Ph] o el Hx-Fe[(P(iPr)2CH2)3B-Ph]. Aquestes espcies han estat estudiades computacionalment, mitjanant la combinaci de mtodes del funcional de la densitat calibrats mitjanant clculs ab initio. Els resultats obtinguts mostren que les superfcies denergia potencial singlet, triplet i quintet es creuen al llarg de les reaccions descrites. La reacci dactivaci del pre-catalitzador s una reacci multi spin-prohibida (ms dun canvi despn), en la que el mecanisme preferit addiciona primer hidrogen i desprs la fosfina, el pas determinant de la velocitat s el creuament de la superfcie denergia potencial quintet a la triplet a la geometria del reactiu, que es produeix amb una barrera daproximadament 18 kcal/mol. La reacci dhidrogenaci dolefines en canvi pot ser o no una reacci espn prohibida depenent de les condicions en que es dugui a terme. En cas de que la reacci es dugui a terme en un excs dhidrogen, en el mecanisme principal lespcie activa seria el (H2)H-Fe[(P(iPr)2CH2)3B-Ph] singlet en el seu estat fonamental que hidrogenaria lolefina sense cap pas espn prohibit. Aquest mecanisme s el de barrera ms baixa per sespera que estigui ms desafavorit entropicament. Si les condicions no sn dun important excs dhidrogen, llavors lespcie activa sespera que sigui H-Fe[(P(iPr)2CH2)3B-Ph], la reacci llavors seria multi espn prohibida amb una barrera de unes 13 kcal/mol corresponents al creuament entre la superfcie quintet i triplet a la geometria del H-Fe[(P(iPr)2CH2)3B-Ph].
Resumo:
Treaty Establishing the European Community, operative until December 1st 2009, had already established in its article 2 the mission of the up until then European Community and actual European Union is to promote an harmonious, equilibrated and sustainable development of the economic activities of the whole Community. This Mission must be achieved by establishing a Common Market, an Economic and Monetary Union and the realization of Common Policies. One of the instruments to obtain these objectives is the use of free circulation of people, services and capitals inside the Common and Interior Market of the European Union. The European Union is characterized by the confirmation of the total movement of capitals, services and individuals and legal peoples freedom; freedom that was already predicated by the Maastricht Treaty, through the suppression of whatever obstacles which are in the way of the objectives before exposed. The old TEC in its Title III, now Title IV of the Treaty on the Functioning of the European Union, covered the free circulation of people, services and capitals. Consequently, the inclusion of this mechanism inside one of the regulating texts of the European Union indicates the importance this freedom supposes for the European Union objectives development. Once stood up the relevance of the free movement of people, services and capitals, we must mention that in this paper we are going to centre our study in one of these freedoms of movement: the free movement of capital. In order to analyze in detail the free movement of capital within the European framework, we are going to depart from the analysis of the existent case law of the Court of Justice of the European Union. The use of jurisprudence is basic to know how Community legislation is interpreted. For this reason, we are going to develop this work through judgements dictated by the European Union Court. This way we can observe how Member States regulating laws and the European Common Law affect the free movement of capital. The starting point of this paper will be the Judgement C-67/08 European Court of Justice of February 12th 2009, known as Block case. So, following the argumentation the Luxemburg Court did about the mentioned case, we are going to develop how free movement of capital could be affected by the current disparity of Member States legislation. This disparity can produce double taxation cases due to the lack of tax harmonized legislation within the interior market and the lack of treaties to avoid double taxation within the European Union. Developing this idea we are going to see how double taxation, at least indirectly, can infringe free movement of capital.
Resumo:
El GB virus C (GBV-C) o virus de l'hepatitis G (HGV) es un virus format per una nica cadena de RNA que pertany a la familia Flaviviridae. En els ltims anys, s'han publicat nombrosos treballs en els quals s'associa la coinfecci del GBV-C i del virus de la immunodeficincia humana (VIH) amb una menor progressi de l'esmentada malaltia aix com amb una major supervivncia dels pacients una vegada que la SIDA s'ha desenvolupat. El mecanisme pel qual el virus GBV-C/HGV exerceix un efecte protector en els pacients amb VIH encara no est descrit. Lestudi de la interacci entre els virus GBVC/HGV i VIH podria donar lloc al desenvolupament de nous agents teraputics per al tractament de la SIDA.Treballs recents mostren com la capacitat inhibitria del virus del GBV-C/HGV s deguda a la seva glicoproteina estructural E2. Sha vist que aquesta proteina seria capa dinhibir la primera fase de replicaci de VIH, aix com la uni i la fusi amb les membranes cellulars. Sobre la base daquests estudis, lobjectiu daquest treball ha estat seleccionar inhibidors del pptid de fusi del VIH utilitzant pptids sinttics de la proteina E2 del GBV-C/HGV. El treball realitzat ha consistit en estudiar, utilitzant assajos biofsics de leakage i de lipid mixing, la capacitat dels pptids de la proteina estructural del virus del GBV-C/HGV per inhibir la interacci i el procs de desestabilitzaci de membranes indudes pel pptid de fusi de la glicoproteina de lembolcall, GP41, del VIH. Aquests assajos, com es descriu en treballs anteriors, han resultat tils per a la selecci i la identificaci de compostos amb activitat especfica anti-GP41. Es pot afirmar que efectivament els pptids seleccionats de la proteina E2 del virus del GBV-C/HGV inhibeixen lactivitat del pptid de fusi del VIH probablement com a consequncia dun canvi conformacional en aquest darrer.
Resumo:
Aquest treball es basa en lestudi de dues malalties lisosmiques: la malaltia de Niemann-Pick A/B (NPAB) i la malaltia de Niemann-Pick tipus C (NPC). En relaci a la malaltia de NPAB, sha realitzat lexpressi in vitro dalgunes de les mutacions de canvi daminocid trobades en pacients espanyols per tal de detectar les activitats enzimtiques residuals. Totes les mutacions presenten una activitat molt baixa, gaireb nulla, excepte la p.L225P i la R608del que tenen un 11% i 20% dactivitat respectivament. Els resultats obtinguts sn coherents amb la severitat del fenotip que presenten els pacients. Daltra banda, sha caracteritzat un allel amb una mutaci que afecta a una posici poc conservada dun donador de splicing i que produeix la generaci de trnscrits aberrants corresponents a trnscrits minoritaris de SMPD1, prviament descrits, que no codifiquen per protena funcional. Respecte a malaltia de NPC, sha realitzat una anlisi molecular de pacients espanyols prviament estudiats identificant, en la majoria dels casos, la segona mutaci responsable de la patologia. Sha descrit per primer cop per aquesta malaltia una gran deleci que inclou el gen NPC1 i altres gens flanquejants i sha estudiat lefecte que tenen les mutacions de splicing trobades a nivell de RNA. Per una daquestes mutacions, c.1554-1009G&A, sha assajat amb xit una estratgia teraputica basada en la utilitzaci doligonuclotids antisentit. Daltra banda, sest desenvolupant un model cellular neuronal de la malaltia de Niemann-Pick tipus C, basat en la utilitzaci de RNAs dinterferncia, sobre el qual es podran assajar possibles estratgies teraputiques en un futur.
Resumo:
Pensar en William Shakespeare, apropar-se a una de l'obres qu ms tinta han fet crrer, se'ns presenta com voler trobar una agulla en un paller. Amb tot, aquest treball de recerca a volgut discernir la dramatrgia de Shakespeare, des de l'ptica espacial i esttica. El seu marc, a l'Anglaterra renaixentista -ss,XVI-XVII-, s: l'abundosa legislaci -important l'Acta promulgada l'any 1572, per la reina Elisabet I-; la tipologia constructiva i formal del Lloc del Teatre, amb la formulaci empresarial qu sen deriva; l'altre element, la participaci de l'espectador implcit. Conclusivament, com l'artialitzaci shakespeariana s'insereix, podem dir, 'dramatolgicament', dins l'historiografia general del teatre.
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We discuss necessary as well as sufficient conditions for the second iterated local multiplier algebra of a separable C*-algebra to agree with the first.
Change in individual growth rate and its link to gill-net fishing in two sympatric whitefish species
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Size-selective fishing is expected to affect traits such as individual growth rate, but the relationship between the fishery-linked selection differentials and the corresponding phenotypic changes is not well understood. We analysed a 25-year monitoring survey of sympatric populations of the two Alpine whitefish Coregonus albellus and C. fatioi. We determined the fishing-induced selection differentials on growth rates, the actual change of growth rates over time, and potential indicators of reproductive strategies that may change over time. We found marked declines in adult growth rate and significant selection differentials that may partly explain the observed declines. However, when comparing the two sympatric species, the selection differentials on adult growth were stronger in C. albellus while the decline in adult growth rate seemed more pronounced in C. fatioi. Moreover, the selection differential on juvenile growth was significant in C. albellus but not in C. fatioi, while a significant reduction in juvenile growth over the last 25 years was only found in C. fatioi. Our results suggest that size-selective fishing affects the genetics for individual growth in these whitefish, and that the link between selection differentials and phenotypic changes is influenced by species-specific factors.
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Los dientes son una importante fuente de informacin en el estudio de poblaciones del pasado. El estudio de las enfermedades dentales en restos esquelticos antiguos busca reconstruir la forma de vida de las poblaciones antiguas relacionadas con su estado de salud y enfermedad.
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If A is a unital quasidiagonal C*-algebra, we construct a generalized inductive limit BA which is simple, unital and inherits many structural properties from A. If A is the unitization of a non-simple purely infinite algebra (e.g., the cone over a Cuntz algebra), then BA is tracially AF which, among other things, lends support to a conjecture of Toms.
Resumo:
"Vegeu el resum a l'inici del document del fitxer adjunt"
Protena C-Reactiva com a marcador biolgic de Dehiscncia dAnastomosi en Cirurgia Colo-rectal electiva
Resumo:
Estudi prospectiu de 208 pacients intervinguts de Cirurgia Colo-Rectal electiva amb anastomosi. Lobjectiu s avaluar el valor de la monitoritzaci de la Protena C-Reactiva (PCR) com a marcador biolgic preco de Dehiscncia dAnastomosi. La disminuci de la PCR entre el segon i el cinqu dia del postoperatori de ms del 39% t un valor predictiu negatiu del 97%, pel qu pensem que hauria de ser una eina a tenir en compte en un protocol de fast-track. La PCR ha demostrat ser un parmetre ms fiable que els parmetres de resposta inflamatria sistmica (recompte leucocitari, freqncia cardaca, freqncia respiratria i temperatura).
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We show that nuclear C*-algebras have a re ned version of the completely positive approximation property, in which the maps that approximately factorize through finite dimensional algebras are convex combinations of order zero maps. We use this to show that a separable nuclear C*-algebra A which is closely contained in a C*-algebra B embeds into B.
Resumo:
Report for the scientific sojourn at the the Philipps-Universitt Marburg, Germany, from september to december 2007. For the first, we employed the Energy-Decomposition Analysis (EDA) to investigate aromaticity on Fischer carbenes as it is related through all the reaction mechanisms studied in my PhD thesis. This powerful tool, compared with other well-known aromaticity indices in the literature like NICS, is useful not only for quantitative results but also to measure the degree of conjugation or hyperconjugation in molecules. Our results showed for the annelated benzenoid systems studied here, that electron density is more concentrated on the outer rings than in the central one. The strain-induced bond localization plays a major role as a driven force to keep the more substituted ring as the less aromatic. The discussion presented in this work was contrasted at different levels of theory to calibrate the method and ensure the consistency of our results. We think these conclusions can also be extended to arene chemistry for explaining aromaticity and regioselectivity reactions found in those systems.In the second work, we have employed the Turbomole program package and density-functionals of the best performance in the state of art, to explore reaction mechanisms in the noble gas chemistry. Particularly, we were interested in compounds of the form H--Ng--Ng--F (where Ng (Noble Gas) = Ar, Kr and Xe) and we investigated the relative stability of these species. Our quantum chemical calculations predict that the dixenon compound HXeXeF has an activation barrier for decomposition of 11 kcal/mol which should be large enough to identify the molecule in a low-temperature matrix. The other noble gases present lower activation barriers and therefore are more labile and difficult to be observable systems experimentally.
