95 research outputs found
Síntese do 5-Acetóxi 7,7-Dimetóxi-Biciclo [2,2,1] hepta-2-eno enantiomericamente puro a partir do hexaclorociclopentadieno
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Síntese do 7,7-Dimetoxi- Biciclo [2,2,1] Hepta-2-Eno a partir do Hexaclorociclopenta-Dieno
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Ocharte, sucesor de Juan Pablos. Historias. Revista de la Dirección de Estudios Históricos. Num. 24 (1990) abril-septiembre
No full text1 Jacques Le Goff, Roger Chartier y Jacques Revel, La nouvelle histoire, Paris, CEPL, 1978, p. 491. Publicado en español como La nueva historia, Bilbao, Ediciones Mensajero, 1988.2 Alexandre A.M. Stols, Antonio de Espinosa, el segundo impresor mexicano, México, UNAM, Instituto Bibliográfico Mexicano, Biblioteca Nacional, 1962, 120 pp.3 Otro caso fue el de Cornelio Adrián César, procesado en 1597-1601 por su origen luterano. Cfr. Ernesto de la Torre Villar, Breve historia del libro en México, México, UNAM, 1987, p. 113.Reseña del libro “Stols, Alexandre A.M., Pedro Ocharte: el tercer impresor mexicano, Reimp. México, UNAM, Instituto de Investigaciones Bibliográficas, Biblioteca Nacional, 1990, 138 pp.” Para abordar la historia del libro, Roger Chartier plantea que hay que tomar en cuenta la historia económica que nos acerca a cuestiones como itinerarios y volúmenes de comercio de las librerías, a la geografía de los talleres, a las áreas de la producción impresa, que se relacionan a su vez con una historia social de los productores y vendedores de libros, y de los aprendices, los prensistas, los maestros impresores, los libreros y los editores. Esto sin dejar de lado, claro está, cuestiones importantes como la de la lectura y los lectores, y la bibliografía, entre otros
Variação percentual de produtos na reação de acetilação do isodrin em função da temperatura e tempo de reação
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Síntese do Endo-Exo Tetraciclico [6.2.1.33,6.02,7]dodec-9,10-Epoxi-4-Ona a partir do aldrin
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Steady-state kinetics of indole-3-glycerol phosphate synthase from Mycobacterium tuberculosis
No full textIndole-3-glycerol phosphate synthase (IGPS) catalyzes the irreversible ring closure of 1-(o-carboxyphenylamino)-1-deoxyribulose 5-phosphate (CdRP), through decarboxylation and dehydration steps, releasing indole-3-glycerol phosphate (IGP), the fourth step in the biosynthesis of tryptophan. This pathway is essential for Mycobacterium tuberculosis virulence. Here we describe the cloning, expression, purification, and kinetic characterization of IGPS from M. tuberculosis. To perform kinetic studies, CdRP was chemically synthesized, purified, and spectroscopically and spectrometrically characterized. CdRP fluorescence was pH-dependent, probably owing to excited-state intramolecular proton transfer. The activation energy was calculated, and solvent isotope effects and proton inventory studies were performed. pH-rate profiles were carried out to probe for acid/base catalysis, showing that a deprotonated residue is necessary for CdRP binding and conversion to IGP. A model to describe a steady-state kinetic sequence for MtIGPS-catalized chemical reaction is proposed.</p
PESI - a taxonomic backbone for Europe
No full textThis is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
The attached file is the published version of the article.NHM Repositor
Testing the evolutionary link between submillimetre galaxies and quasars: CO observations of QSOs at z~2
No full textWe have used the IRAM Plateau de Bure millimetre interferometer and the UKIRT 1–5 μm Imager Spectrometer (UIST) to test the connection between the major phases of spheroid growth and nuclear accretion by mapping CO emission in nine submillimetre-detected QSOs at z= 1.7–2.6 with black hole (BH) masses derived from near-infrared spectroscopy. When combined with one QSO obtained from the literature, we present sensitive CO(3–2) or CO(2–1) observations of 10 submillimetre-detected QSOs selected at the epoch of peak activity in both QSOs and submillimetre (submm) galaxies (SMGs). CO is detected in 5/6 very optically luminous (MB∼−28) submm-detected QSOs with BH masses MBH≃ 109–1010 M⊙, confirming the presence of large gas reservoirs of Mgas≃ 3.4 × 1010 M⊙. Our BH masses and dynamical mass constraints on the host spheroids suggest, at face value, that these optically luminous QSOs at z= 2 lie about an order of magnitude above the local BH–spheroid relation, MBH/Msph, although this result is dependent on the size and inclination of the CO-emitting region. However, we find that their BH masses are ∼30 times too large and their surface density is ∼300 times too small to be related to typical SMGs in an evolutionary sequence. Conversely, we measure weaker CO emission in four fainter (MB∼−25) submm-detected QSOs with properties, BH masses (MBH≃ 5 × 108 M⊙), and surface densities similar to SMGs. These QSOs appear to lie near the local MBH/Msph relation, making them plausible ‘transition objects’ in the proposed evolutionary sequence linking QSOs to the formation of massive young galaxies and BHs at high redshift. We show that SMGs have a higher incidence of bimodal CO line profiles than seen in our QSO sample, which we interpret as an effect of their relative inclinations, with the QSOs seen more face-on. Finally, we find that the gas masses of the four fainter submm-detected QSOs imply that their star formation episodes could be sustained for ∼10 Myr, and are consistent with representing a phase in the formation of massive galaxies which overlaps a preceding SMG starburst phase, before subsequently evolving into a population of present-day massive ellipticals
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