2,482 research outputs found
[Cédula, 1798-02-21]
Copia digital. Valladolid : Junta de Castilla y León. ConsejerÃa de Cultura y Turismo, 2009-2010Port. con esc. rea
TÃtulo: Pragmatica 1676 04 29
Hay un ejemplar encuadernado con: Valencia. Estado del año 1765 en que se manifiesta el resumen de sus rentas de proprios y arbitrios y de los salarios ... (XVIII/911).Texto original fechado en Aranjuez a 26 de abril de 1761Copias fechadas en Madrid a 29 de abril de 1761 y en Valencia a 14 de mayo de 1761Sign.: [ ]3Port. con esc. xi
Panegyrico que en diez y ocho de agosto ... se predico en la Iglesia Parroquial de Santa Marina, religión de San Juan, de la ciudad de Toro ...
Sign.: [calderón] 4, 2[calderón] 3, A-D 4, E 2.Texto con apostillas marginales.Port. con orla tip.Letra capital ornada
Juicio crÃtico del estado moral y material de Segovia al presente y medios más discretos y oportunos para lograr su engrandecimiento
Estudio premiado por la Sociedad Económica Castellana de Amigos del PaÃs, en el certamen cientÃfico literario celebrado el 25 de junio de 1896Copia digital. Valladolid : Junta de Castilla y León. ConsejerÃa de Cultura y Turismo, 2009-201
Philippica zelosa, y religiosa invectiva, execracion de los torpes, y abominables sacrilegios, con que ultrajaron los hereges el Santissimo Sacramento del Altar, las sagradas imagenes, y templos en la irrupcion que hizieron à Castilla año de 1710
Copia digital. Valladolid : Junta de Castilla y León. ConsejerÃa de Cultura y Turismo, 2009-2010Texto a lÃnea tirada con apostillas marginales, separadas del texto por un filetePort. orlad
Biolixivia??o de sulfetos secund?rios de cobre por micro?organismos mes?filos em diferentes reatores agitados.
Programa de P?s-Gradua??o em Engenharia de Materiais. Departamento de Engenharia Metal?rgica, Escola de Minas, Universidade Federal de Ouro Preto.A biolixivia??o de cobre a partir de sulfetos secund?rios, tais como a calcocita e a
bornita, ? amplamente aplicada industrialmente em v?rios pa?ses do mundo. Isso ocorre
porque esses sulfetos s?o facilmente oxidados pelo ?on Fe3+ produzido por microorganismos
de biolixivia??o. No entanto, a biolixivia??o pode ser severamente
impactada se o min?rio portar impurezas sol?veis que podem afetar o crescimento
bacteriano. Este ? o caso do fluoreto, que existe como HF nas condi??es ?cidas aplicadas
na biolixivia??o de metais b?sicos. Este ?ltimo pode atravessar membranas celulares e
dissociar dentro da c?lula (por causa de seu pH neutro), reduzindo o crescimento
bacteriano. Nesta disserta??o foi investigada a influ?ncia da concentra??o de fl?or sobre
o crescimento de Acidithiobacillus ferrooxidans e revelou que 20 mg.L?1 F?total inibiram a
biooxida??o do ?on Fe2+. Tal inibi??o foi superada por adi??o de sulfato de alum?nio ao
meio de crescimento. Em seguida, foi estudada a biolixivia??o de um min?rio de cobre
secund?rio portador de fl?or (contendo calcocita e bornita) pela cultura mes?fila. Os
efeitos do pH bem como as concentra??es de Fe2+, Al3+ e Mg2+ na extra??o de cobre
foram determinados, os experimentos foram realizados em frascos Erlenmeyer (250 mL)
contendo 100 mL de solu??o e porcentagem de s?lidos a 5% (p/v) agitada a 150 min?1.
A cin?tica de lixivia??o da amostra foi ligeiramente afetada pelo pH e concentra??es do
?on Fe2+, sendo que as maiores extra??es de cobre foram observadas para pH 1,6?1,8 e
5?10 g.L?1 Fe2+. As concentra??es de alum?nio (at? 5 g.L?1) melhoraram a cin?tica de
extra??o do cobre ? medida que os ?ons fluoreto foram complexados pelo elemento e a
extra??o final de cobre atingiu 75%. Al?m disso, propondo uma adapta??o ao programa
de ensaios metal?rgicos visando uma futura aplica??o industrial de lixivia??o em pilhas,
especificamente em sistemas agitados, a segunda parte da disserta??o buscou comparar
o perfil de lixivia??o de tr?s diferentes reatores (frascos Erlenmeyer, garrafas rotativas
e um biorreator agitado mecanicamente) durante a biolixivia??o de duas amostras de
sulfetos secund?rios com diferentes teores de cobre e fl?or. Na aus?ncia de uma fonte
externa de alum?nio, os ensaios em Erlenmeyer n?o mostraram qualquer aumento no
potencial da solu??o, independentemente da amostra de min?rio estudada.
Concentra??es de fl?or e alum?nio em torno de 300 mg.L?1 foram registradas neste
reator e a raz?o Al/F em torno de 1 explicou o baixo potencial registrado. Por outro lado,
nos ensaios em garrafa e biorreator, a amostra de min?rio com menor teor de cobre
produziu alum?nio (530 mg.L?1) acima das concentra??es de fl?or (380 mg.L?1), de modo
que esse maior ?ndice Al/F estimulou o crescimento bacteriano. Isto se justificou, pelo
fato do potencial da solu??o ter atingido valores acima de 600 mV ao final do
experimento, o que indicou o crescimento bacteriano nesses reatores. Quando o
alum?nio foi adicionado ao meio de crescimento, o potencial da solu??o aumentou
exponencialmente, indicando boa atividade de biolixivia??o e at? 97% de extra??o de
cobre foi observada nos tr?s reatores, mas as garrafas rotativas apresentaram uma
cin?tica de lixivia??o mais r?pida devido a altas popula??es bacterianas (> 108 c?lulas.
mL?1) proporcionada por uma melhor aera??o da solu??o (6 mg.L?1 como a concentra??o
de oxig?nio dissolvido).Copper bioleaching from secondary sulphides such as chalcocite and bornite is widely
applied industrially in several countries worldwide. This is because these sulphides are
easily oxidized by the ferric iron produced by bioleaching microorganisms.
Notwithstanding, bioleaching can be severely hampered if the ore contains soluble
impurities which can affect bacterial growth. This is the case of fluoride, which exists as
HF in the acid conditions applied in the bioleaching of base metals. The latter can cross
cell membranes and dissociate inside the cell (because of its neutral pH) reducing the
bacterial growth. The current dissertation investigated initially the fluoride
concentration which impaired the growth of At. ferrooxidans and revealed that 20 mg.L?
1 Ftot inhibited ferrous iron bio?oxidation. Such inhibition was overcome by aluminium
sulphate supplementation to the growth medium. Subsequently the bioleaching of a
fluoride?bearing secondary copper ore (containing chalcocite and bornite) by the
mesophile culture was studied. The effects of pH as well as the concentrations of Fe2+,
Al3+ and Mg2+ on copper extraction were determined in experiments were performed in
Erlenmeyer flasks (250 mL) containing 100 mL of a 5% (w/v) pulp stirred at 150 min?1.
The leaching kinetics of the sample was slightly affected by both pH and ferrous iron
concentrations and the largest copper extractions were observed for pH 1.6?1.8 and 5?
10 g.L?1 Fe2+. Aluminium concentrations (up to 5 g.L?1) improved the copper extraction
kinetics as fluoride ions were complexed by the element and the final copper extraction
reached 75%. In addition, the metallurgical testwork proposed in feasibility studies for
leaching projects comprise different type of reactor experiments such as rolling bottles
whereas shaking flasks tests are of widespread use in academic research. Therefore the
second part of the current dissertation sought to compare the leaching profile of three
different reactors (Erlenmeyer flasks, rolling bottles and a mechanically stirred
bioreactor) during bioleaching of two samples of the secondary sulphide ore with
different copper and fluoride content. In the absence of an external aluminium source,
the shaking flask experiments did not show any increase in the solution potential,
regardless of the ore sample studied. Fluoride and aluminium concentrations around
300 mg.L?1 were recorded in this reactor and the Al/F ratio around 1 explained the low
potential recorded. Conversely, the ore sample with the lower fluoride content
produced aluminium (530 mg.L?1) above fluoride (380 mg.L?1) concentrations so that
such higher Al/F ratio fostered bacterial growth. This justified the solution potential
attaining values above 600 mV by the end of the experiment, which indicated bacterial
growth in that reactor. When aluminium was added to the growth medium the solution
potential increases exponentially indicating good bioleaching activity and up to 97%
copper extraction was observed in the three reactors, but the rolling bottles depicted a
faster leaching kinetics due to high bacterial populations (>108 cells.mL?1) provided by a
better aeration of the solution (6 mg.L?1 as the dissolved oxygen concentration)
A novel supramolecular organic-inorganic adduct containing alpha-Keggin-type [PW12O40](3-) anions and benzo-15-crown-5 molecules
The structure of the title compound, tris(hydroxonium) 12-
phosphato-tetracosa- 2-oxo-dodecaoxododecatungsten hexakis(
benzo-15-crown-5)±methanol±water (1/1/1), (H3O)3-
[PW12O40] 6C14H20O5 CH3OH H2O (where C14H20O5 is
benzo-15-crown-5), has been determined at 180 K.
[PW12O40]3ÿ
anions are typical of -Keggin structures, and
the [H3O (C14H20O5)2]+ sandwich-type moieties contain a
large number of short O O close contacts, suggesting strong
hydrogen bonding within them
The ₉₅RGD₉₇ sequence on the A alpha chain of fibrinogen is essential for binding to its erythrocyte receptor
Background: Erythrocyte aggregation, a cardiovascular risk factor, is increased by high plasma fibrinogen levels. Here, the effect of different fibrinogen mutations on binding to its human erythrocyte receptor was assessed in order to identify the interaction sites.
Methods: Three fibrinogen variants were tested, specifically mutated in their putative integrin recognition sites on the Aα chain (mutants D97E, D574E and D97E/D574E) and compared with wild-type fibrinogen.
Results: Atomic force microscopy-based force spectroscopy measurements showed a significant decrease both on the fibrinogen–erythrocyte binding force and on its frequency for fibrinogen with the D97E mutation, indicating that the corresponding arginine–glycine–aspartate sequence (residues 95–97) is involved in this interaction, and supporting that the fibrinogen receptor on erythrocytes has a β3 subunit. Changes in the fibrin clot network structure obtained with the D97E mutant were observed by scanning electron microscopy.
Conclusion: These findings may lead to innovative perspectives on the development of new therapeutic approaches to overcome the risks of fibrinogen-driven erythrocyte hyperaggregation
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