פרסומים

Three cannabis constituents, cannabidiol (1), Delta(8)-tetrahydrocannabinol (3), and cannabinol (5), were oxidized to their respective para-quinones 2, 4, and 6. In the 1960s, the oxidized product 4 had been assigned a para-quinone structure, which was later modified to an ortho-quinone. To distinguish between the two possible quinone structures, a detailed NMR investigation was undertaken. The original para-quinone structure was confirmed. X-ray crystallography elucidated the structures of the crystalline 2 and 6. All three compounds displayed antiproliferative activity in several human cancer cell lines in vitro, and quinone 2 significantly reduced cancer growth of HT-29 cancer in nude mice.

Several representative oxazaborolidines have been synthesized and evaluated against S. mutans for antibacterial activity. This is the first reported antibacterial activity of this class of compounds. The minimal inhibitory concentration values ranged from 0.53 to 6.75 mM.

This paper sets forth a model of contracting for delivery in an environment with time to build and adverse selection. The optimal contract is derived and characterized and it takes the form of a deadline contract. Such a contract stipulates a deadline for delivery for each possible type of agent efficiency. The optimal contract induces inefficient delay by using delivery time as a screening device. Furthermore, rents are decreasing in the agent's efficiency. In meeting the deadline, the agent's effort is strictly increasing over time, due to discounting. It is shown that increasing the project's gross value decreases delivery time, while the scale or difficulty of the project decreases it. Last, it is shown that the agent's rents are increasing in both project difficulty and gross project value.

In addition to the familiar bending and stretching deformations, lipid monolayers and bilayers in their disordered state are often subjected to tilt deformations, occurring for instance in structural rearrangements accompanying membrane fusion, or upon insertion of ‘‘oblique’’ hydrophobic proteins into lipid bilayers. We study the elastic response of a flat lipid monolayer to a tilt deformation, using the spatial and conformational average of the chain end-to-end vector from the membrane normal to define a macroscopic membrane tilt. The physical origin and magnitude of the corresponding tilt modulus k(t) is analyzed using two complementary theoretical approaches. The first is a phenomenological model showing that the tilt and bending deformations are decoupled and the effects of inter-chain correlations on the tilt modulus is small. The second is based on a molecular-level mean-field theory of chain packing, enabling numerical evaluation of the tilt modulus for realistic, multi-conformation, chain models. Both approaches reveal that the tilt modulus involves two major contributions. The first is elastic in origin, arising from the stretching of the hydrocarbon chains upon a tilt deformation and reflecting the loss of chain conformational freedom associated with chain stretching. The second, purely entropic, contribution results from the constraints imposed by a tilt deformation on the fluctuations of chain director orientations. Using the chain-packing theory we compute the two contributions numerically as a function of the cross-sectional area per chain. The elastic and entropic terms are shown to dominate the value of k(t) for small and large areas per chain, respectively. For typical cross-sectional areas of lipid chains in biological membranes they areof comparable magnitude, yielding k(t) approximate to 0.2k(B)T/Angstrom(2).

In most industries, ranging from information systems development to construction, an overwhelming proportion of projects are delayed beyond estimated completion time. This fact constitutes somewhat of a puzzle for existing theory. The present paper studies project delays and optimal contracts under moral hazard in a setting with time to build. Within this setup, project delays are found to be most likelyto happen at early stages of development, and intimately connected to the degree ofcommitment of the procurer and the class of contracts that can be enforced. The firstbest,optimal spot contracting and optimal long-term contract scenarios are analyzed, aswell as commonly encountered additional constraints on the long-term contract.

Beginning with Durkheim’s analysis of secular rituals, this essay explores the spillover from love-talk to religious-talk in Plato’s ’Phaedrus’, Shakespeare’s ’Romeo and Juliet’ and Sacher-Masoch’s ’Venus in Furs’. Religious categories are deployed in these texts in three distinct ways: in Plato, the temptation to worship the beloved is present but is also avoided because of shame; in Shakespeare, the category of worship enables positing the loved one’s supposed holiness in order for it to be transgressed; whilst in Sacher-Masoch, worship and ritual in relation to the love object are literally acted out. I claim that such moments exemplify three ways of relating to erotic merging and three modalities of creating erotic force. The essay’s grander thesis is that the contemporary aggrandizing of love, the present-day "religion of love" in secular culture, can be understood through erotic love’s (rather limited) ability to channel and feed needs that were previously organized into religious experience.

U-type microemulsions based on five food-grade ingredients, water, R(+)-limonene, ethanol, propylene glycol, (or glycerol) and ethoxylated sorbitan esters (Tween 60 or Tween 80) were studied. The U-type phase diagram is characterized by a unique compn., fully dilutable with the aq. phase that inverts progressively from an L2 phase to an L1 phase via a bicontinuous structure without phase sepn. The oil conc.' (surfactant, oil, alc.) is loaded with water-insol. solubilizates (phytosterols, lutein and lycopene) a few times more than the soly. capacity of the oil phase (without the surfactant). The max. solubilization capacity ($μ$-value) was obtained for phytosterols and the min. solubilization capacity was for lycopene. All solubilization values decrease with aq. phase diln. If solubilization is calcd. on the basis of the oil content ($\alpha$-value) or the oil + surfactant ($\gamma$-value) it is obvious that the interface plays a key role in the solubilization.The lipophilic solubilizates (by SD-NMR) are tightly packed and well accommodated at interfaces that convex (hydrophobic-in-nature) toward the water (water-in-oil microemulsions). Solubilization at the bicontinuous interface is lower and the solubilizates are loose packed. Once phase inversion occurs, and the interface becomes more hydrophilic and transforms into oil-in-water microemulsion, the solubilization becomes minimal, and most of the solubilizate desorbs. Phytosterols and lycopene induce the transition from W/O to bicontinuous and it occurs at lower water content (ca. 25 wt% aq. phase in the presence of solubilizate vs. 35 wt% in its absence). The transition from bicontinuous to O/W is mostly unaffected (or undetected) since the interface flattens out and the solubilizate does not affect the curvature much. Lutein displays different behavior, the transition, from bicontinuous phase to O/W, occurs at higher water contents because its adsorption and packing are significantly tighter. Solubilization capacities of each of the nutraceuticals were detd. for all diln. compns. [on SciFinder(R)]