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A carbon-rich black layer, dating to approximately 12.9 ka, has been previously identified at approximately 50 Clovis-age sites across North America and appears contemporaneous with the abrupt onset of Younger Dryas (YD) cooling. The in situ bones of extinct Pleistocene megafauna, along with Clovis tool assemblages, occur below this black layer but not(More)
The purpose of this paper is 2-fold. First, we present several extensions to the ONIOM(QM:MM) scheme. In its original formulation, the electrostatic interaction between the regions is included at the classical level. Here we present the extension to electronic embedding. We show how the behavior of ONIOM with electronic embedding can be more stable than(More)
We have recently reported an influenza virus neuraminidase inhibitor, RWJ-270201 (BCX-1812), a novel cyclopentane derivative discovered through structure-based drug design. In this paper, we compare the potency of three compounds, RWJ-270201, oseltamivir, and zanamivir, against neuraminidase enzymes from various subtypes of influenza. RWJ-270201 effectively(More)
Earlier results suggested that although the N-deoxyribosyltransferase from lactobacilli is a convenient tool for the preparation of analogs of 2'-deoxyadenosine, 8-substituted purines do not act as substrates. However, eight of nine 8-substituted purines that were examined proved to be substrates for the transferase from Lactobacillus leichmannii, and(More)
Reaction of 5,6,7,8-tetrahydrofolic acid (THF,7) with phosgene, thiophosgene, and cyanogen bromide gave the bridged derivatives, 5,10-(CO)-THF (8), 5,10-(CS)-THF (9), and 5,10-(C = NH)-THF (11), respectively. Catalytic hydrogenation of 10-(chloroacetyl)folic acid (2) gave 5,10-(CH2CO)-THF (12). A similar reaction with 10-(3-chloropropionyl)folic acid (3)(More)
The present study deals with the discovery and partial characterization of specific binding proteins for retinol and retinoic acid from filarial parasites (worms of the superfamily Filarioidea), including those from two species of Onchocerca. These binding proteins, which are distinct in their physicochemical properties and in the mode of ligand(More)
The mechanoreceptive lateral line system in fishes detects hydrodynamic stimuli and plays a critical role in many fundamental behaviours, including orientation to water currents and the detection of stationary objects, prey and predators. Interspecific variation in lateral line structure may result from a process of functional adaptation, with the(More)