453 research outputs found
TĂtulo: TeologĂa catequĂstica
Copia digital. Valladolid : Junta de Castilla y LeĂłn. ConsejerĂa de Cultura y Turismo, 2009-201
Scielta di notabili avvertimenti pertinenti a cavalli..
Enc. en pergER
Ordini di cavalcare et modi di conoscere le natvre de cavalli, di emendare i lor vitii...
ERJApostillasReclamosSign.: [cruz]6, A-K8, L
Claudii Ptolemaei liber de Analemmate
Marca tipográfica en portadaSignaturas: *\p4\s, A-Z\p4\s, &\p4\s.Las ilustraciones son grabados xilografiado
Solving Nonlinear Parabolic Equations by a Strongly Implicit Finite-Difference Scheme
We discuss the numerical solution of nonlinear parabolic partial differential
equations, exhibiting finite speed of propagation, via a strongly implicit
finite-difference scheme with formal truncation error . Our application of interest is the spreading of
viscous gravity currents in the study of which these type of differential
equations arise. Viscous gravity currents are low Reynolds number (viscous
forces dominate inertial forces) flow phenomena in which a dense, viscous fluid
displaces a lighter (usually immiscible) fluid. The fluids may be confined by
the sidewalls of a channel or propagate in an unconfined two-dimensional (or
axisymmetric three-dimensional) geometry. Under the lubrication approximation,
the mathematical description of the spreading of these fluids reduces to
solving the so-called thin-film equation for the current's shape . To
solve such nonlinear parabolic equations we propose a finite-difference scheme
based on the Crank--Nicolson idea. We implement the scheme for problems
involving a single spatial coordinate (i.e., two-dimensional, axisymmetric or
spherically-symmetric three-dimensional currents) on an equispaced but
staggered grid. We benchmark the scheme against analytical solutions and
highlight its strong numerical stability by specifically considering the
spreading of non-Newtonian power-law fluids in a variable-width confined
channel-like geometry (a "Hele-Shaw cell") subject to a given mass
conservation/balance constraint. We show that this constraint can be
implemented by re-expressing it as nonlinear flux boundary conditions on the
domain's endpoints. Then, we show numerically that the scheme achieves its full
second-order accuracy in space and time. We also highlight through numerical
simulations how the proposed scheme accurately respects the mass
conservation/balance constraint.Comment: 36 pages, 9 figures, Springer book class; v2 includes improvements
and corrections; to appear as a contribution in "Applied Wave Mathematics II
Export of functional Streptomyces coelicolor alditol oxidase to the periplasm or cell surface of Escherichia coli and its application in whole-cell biocatalysis
Streptomyces coelicolor A3(2) alditol oxidase (AldO) is a soluble monomeric flavoprotein in which the flavin cofactor is covalently linked to the polypeptide chain. AldO displays high reactivity towards different polyols such as xylitol and sorbitol. These characteristics make AldO industrially relevant, but full biotechnological exploitation of this enzyme is at present restricted by laborious and costly purification steps. To eliminate the need for enzyme purification, this study describes a whole-cell AldO biocatalyst system. To this end, we have directed AldO to the periplasm or cell surface of Escherichia coli. For periplasmic export, AldO was fused to endogenous E. coli signal sequences known to direct their passenger proteins into the SecB, signal recognition particle (SRP), or Twin-arginine translocation (Tat) pathway. In addition, AldO was fused to an ice nucleation protein (INP)-based anchoring motif for surface display. The results show that Tat-exported AldO and INP-surface-displayed AldO are active. The Tat-based system was successfully employed in converting xylitol by whole cells, whereas the use of the INP-based system was most likely restricted by lipopolysaccharide LPS in wild-type cells. It is anticipated that these whole-cell systems will be a valuable tool for further biological and industrial exploitation of AldO and other cofactor-containing enzymes.
Induction chemotherapy stategies for primary mediastinal large B-cell lymphoma with sclerosis: a retrospective multinational study on 426 previously untreated patients.
BACKGROUND AND OBJECTIVES: This multinational retrospective study compares the outcomes of patients with primary mediastinal large B-cell lymphoma (PMLBCL) with sclerosis after first-generation (dose-intensive regimens), third-generation (alternating regimens) and high-dose chemotherapy strategies, frequently with adjuvant radiation therapy. DESIGN AND METHODS: Between August 1981 and December 1999, a total of 426 previously untreated patients with confirmed diagnosis were enrolled in 20 institutions to receive combination chemotherapy with either first generation (CHOP or CHOP-like) regimens, third generation (MACOP-B, VACOP-B, ProMACE CytaBOM) regimens or high-dose chemotherapy (HDS/ABMT). RESULTS: With chemotherapy, complete response (CR) rates were 49% (50/105), 51% (142/277) and 53% (23/44) with first generation, third generation and high-dose chemotherapy strategies, respectively; partial response (PR) rates were 32%, 36% and 35%, respectively. All patients who achieved CR and 124/142 (84%) with PR had radiation therapy on the mediastinum. The final CR rates became 61% for CHOP/CHOP-like regimens, 79% for MACOP-B and other regimens, and 75% for HDS/ABMT. After median follow-ups from attaining CR of 48.5 months for CHOP/CHOP-like regimens, 51.7 months for MACOP-B type regimens and 32.4 months for HDS/ABMT, relapses occurred in 15/64 (23%), 27/218 (12%) and 0/33 (0%) patients, respectively. Projected 10-year progression-free survival rates were 35%, 67% and 78%, respectively (p=0.0000). Projected 10-year overall survival rates were 44%, 71% and 77%, respectively (p=0.0000), after median follow-ups from diagnosis of 52.3 months, 54.9 months and 35.8 months, respectively. INTERPRETATION AND CONCLUSIONS: In patients with PMLBCL with sclerosis, MACOP-B plus radiation therapy may be a better strategy than other treatments; these retrospective data need to be confirmed by prospective studies. The encouraging survival results after high dose chemotherapy require confirmation in selected high-risk patients
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