Endomorphisms of Koszul complexes: formality and application to deformation theory

We study the differential graded Lie algebra of endomorphisms of the Koszul resolution of a regular sequence on a unitary commutative K-algebra R and we prove that it is homotopy abelian over K but not over R (except trivial cases). We apply this result to prove an annihilation theorem for obstructions of (derived) deformations of locally complete intersection ideal sheaves on projective schemes

Formality conjecture for minimal surfaces of Kodaira dimension 0

Let be a polystable sheaf on a smooth minimal projective surface of Kodaira dimension 0. Then the differential graded (DG) Lie algebra of derived endomorphisms of is formal. The proof is based on the study of equivariant minimal models of DG Lie algebras equipped with a cyclic structure of degree 2 which is non-degenerate in cohomology, and does not rely (even for K3 surfaces) on previous results on the same subject

An algebraic proof of Bogomolov-Tian-Todorov theorem

We give a completely algebraic proof of the Bogomolov-Tian-Todorov theorem. More precisely, we shall prove that if X is a smooth projective variety with trivial canonical bundle defined over an algebraically closed field of characteristic 0, then the L-infinity algebra governing infinitesimal deformations of X is quasi-isomorphic to an abelian differential graded Lie algebra.Comment: 20 pages, amspro

HIV-Reverse Transcriptase Inhibition: Inclusion of Ligand-Induced Fit by Cross-Docking Studies

Nonnucleoside reverse transcriptase inhibitors (NNRTIs) have, in addition to the nucleoside reverse transcriptase inhibitors (NRTIs) and protease inhibitors (PIs), a definitive role in the treatment of HIV-1 infections. Since the appearance of HEPT and TIBO, more than 30 structurally different classes of compounds have been reported as NNRTIs, which are specific inhibitors of HIV-1 replication, targeting the HIV-1 reverse transcriptase (RT). Nevirapine and delavirdine are the first formally licensed for clinical use, and others have been licensed afterward, while several are in preclinical or clinical development. The NNRTIs interact with a specific site of HIV-1 RT (nonnucleoside binding site, NNBS) that is close to, but distinct from, the NRTI binding site. In this work we report the application of the Autodock program assessing its usability through reproduction of 41 NNRTI experimental bound conformations. Moreover, cross-docking experiments on the wild-type and mutated RT forms were conducted to take into account the enzyme flexibility as a valuable tool for structure-based drug design (SBDD) studies and to gain insight on the mode of action of new anti-HIV agents active against both wild-type and resistant strains

Radiocarbon Dating in Late-Roman and Medieval Contexts: An Archaeological Excavation in the Center of Florence, Italy

A series of samples for radiocarbon dating were collected in 2005 from the Biblioteca Magliabechiana archaeological excavation area in the center of Florence, Italy, in a project directed by the Dipartimento di Archeologia e Storia delle Arti of the University of Siena, in cooperation with the Soprintendenza per i Beni Architettonici e per il Paesaggio per le province di Firenze e Prato. This area is located near the Uffizi Galleries, close to the Roman town, the Arno River and one of its former tributaries. The area is peculiar for the Florentine urban context because it was free from urban development until the 12th century AD. The exposed stratigraphy showed the presence of several layers composed of natural sediments, partly the result of historical floods. Here, we report a series of 14C measurements on charcoal and seed samples collected on this excavation. 14C dating has been performed in the LABEC laboratory in Florence, on the accelerator mass spectrometry (AMS) beam line of the AMS-IBA 3MV Tandetron accelerator. We also had the opportunity to compare the 14C dates obtained with several series of samples previously collected in nearby archaeological areas. Results were consistent with the data obtained previously and, moreover, offer interesting new aspects to the interpretation of the archaeological findings

Cyclooxygenase-2 inhibitors. 1,5-diarylpyrrol-3-acetic esters with enhanced inhibitory activity toward cyclooxygenase-2 and improved cyclooxygenase-2/cyclooxygenase-1 selectivity.

he important role of cyclooxygenase-2 (COX-2) in the pathogenesis of inflammation and side effect limitations of current COX-2 inhibitor drugs illustrates a need for the design of new compounds based on alternative structural templates. We previously reported a set of substituted 1,5-diarylpyrrole derivatives, along with their inhibitory activity toward COX enzymes. Several compounds proved to be highly selective COX-2 inhibitors and their affinity data were rationalized through docking simulations. In this paper, we describe the synthesis of new 1,5-diarylpyrrole derivatives that were assayed for their in vitro inhibitory effects toward COX isozymes. Among them, the ethyl-2-methyl-5-[4-(methylsulfonyl)phenyl]-1-[3-fluorophenyl]-1H-pyrrol-3- acetate (1d), which was the most potent and COX-2 selective compound, also showed a very interesting in vivo anti-inflammatory and analgesic activity, laying the foundations for developing new lead compounds that could be effective agents in the armamentarium for the management of inflammation and pain

Continental rift architecture and patterns of magma migration: a dynamic analysis based on centrifuge models.

Small-scale centrifuge models were used to investigate the role of continental rift structure in controlling patterns of magma migration and emplacement. Experiments considered the reactivation of weakness zones in the lower crust and the presence of magma at Moho depths. Results suggest that surface deformation, which reflects the weakness zone geometry, exerts a major control on patterns of magma migration. In the case of a single rift segment, the experimental lower crust and magma were both transferred in an extension-parallel direction toward the rift flanks. This lateral migration reflected the dominance of far-field stresses over extension-induced buoyancy forces. Local pressure gradients favored the raise of experimental magma in correspondence of marginal grabens. The lateral migration gave rise to major accumulations below the footwall of major boundary faults, providing the magma source able to feed off-axis volcanoes in nature, as inferred for the Main Ethiopian Rift. In the case of two offset rift segments, a major transfer zone developed. This transfer zone was characterized by prominent experimental lower crust doming and strong magma accumulation. Dynamic analysis showed that the transfer zone development caused a strong pressure difference in a rift-parallel direction, which dominated over the farfield thinning. Owing to this pressure gradient, almost all the underplated experimental magma collected below the lower crust dome, suggesting a rift-parallel (extension-orthogonal) migration. This process has a direct relevance for the localization of magmatic activity at transfer zones in natural continental rifts, such as in the Western Branch of the East African Rift System. Copyright 2004 by the American Geophysical Union