פרסומים

The present study evaluates the effect of a solubilized model drug, diclofenac sodium salt (diclofenac), in our unique new U-type microemulsion system embedded with phosphatidylcholine (PC) in terms of microstructure transformations, phys. properties of the system (viscosity, elec. cond.), droplet sizes and shapes, and nucleation and growth of the droplets. The phys. properties are correlated to the permeability of diclofenac through Caco-2 monolayer cells. The major findings reported are: (1) systems that are rich in surfactant and contain minimal oil phase form a microemulsion that enables high solubilization of diclofenac (20% diclofenac in the oil and surfactant conc. can be fully dild. with water); (2) PC presence at the interface does not affect the size of the O/W droplets, while the presence of diclofenac at the interface decreases the O/W droplet size by an av. of 50%; (3) diclofenac seems to increase incorporation of PC into the W/O interface; (4) diclofenac affects the phys. properties of the microemulsion increasing the viscosity of the W/O microemulsion system and completely changing the cond. profile of the system upon water diln.; (5) cryo-TEM images indicate that above 70% water the droplets are spherical; (6) diclofenac permeability through Caco-2 monolayer cells increases when PC is embedded into the interface. [on SciFinder(R)]

What are the limits of physical computation? In his 'Church's Thesis and Principles for Mechanisms', Turing's student Robin Gandy proved that any machine satisfying four idealised physical 'principles' is equivalent to some Turing machine. Gandy's four principles in effect define a class of computing machines ('Gandy machines'). Our question is: What is the relationship of this class to the class of all (ideal) physical computing machines? Gandy himself suggests that the relationship is identity. We do not share this view. We will point to interesting examples of (ideal) physical machines that fall outside the class of Gandy machines and compute functions that are not Turing-machine computable.

Two 3-aminoalkenylphosphonate compounds 1, 2, and a hydroxyl derivative, 2-(3-hydroxy-3-phenylpropyl)hex-1-enylphosphonate 3, recently synthesized in our lab, have been evaluated for their ability to modulate the production of reactive oxygen intermediates, nitric oxide (NO) and tumor necrosis factor (TNF-alpha) by murine macrophages. We found that all three molecules suppressed generation of reactive oxygen intermediates, NO, and TNF-alpha. However, although 2-(3-hydroxy-3-phenylpropyl)hex-1-enylphosphonate 3 possessed higher activity in suppression of reactive oxygen intermediates and nitric oxide compared to 3-aminoalkenylphosphonates 1 and 2, it showed less activity in the inhibition of tumor necrosis factor release.

In a series of experiments, Bar-Hillel and Budescu (1995) failed to find a desirability bias in probability estimation. The World Cup soccer tournament (of 2002 and 2006) provided an opportunity to revisit the phenomenon, in a context where wishful thinking and desirability bias are notoriously rampant (e.g., Babad, 1991). Participants estimated the probabilities of various teams to win their upcoming games. They were promised money if one particular team, randomly designated by the experimenter, would win its upcoming game. Participants judged their target team more likely to win than other participants, whose promised monetary reward was contingent on the victory of its rival team. Prima facie this seems to be a desirability bias. However, in a follow-up study we made one team salient, without promising monetary rewards, by simply stating that it is "of special interest". Again participants judged their target team more likely to win than other participants, whose "team of special interest" was the rival team. Moreover, the magnitude of the two effects was very similar. On grounds of parsimony, we conclude that what seemed like a desirability bias may just be a salience/marking effect, and – though optimism is a robust and ubiquitous human phenomenon – wishful thinking still remains elusive.In 2008, a shorter version of this paper was published under the title Wishful thinking in predicting world cup results as chapter 2 of Rationality and Social Responsibility (J. Krueger, ed.), 175-186.  In the link todp448, it follows the version published in Psychonomic Bulletin and Review.

One of the most intriguing questions in insurance is the preference of consumers for low or zero deductible insurance policies. This stands in sharp contrast to a theorem proved by Mossin, 1968, that under quite common assumptions when the price of insurance is higher than its actuarial value, then full coverage is not optimal.We show in a series of experiments that amateur subjects tend to underestimate the value of a policy with a deductible and that the degree of underestimation increases with the size of the deductible. We hypothesize that this tendency is caused by the anchoring heuristic. In particular, in pricing a policy with a deductible subjects first consider the price of a full coverage policy. Then they anchor on the size of the deductible and subtract it from the price of the full coverage policy. However, they do not adjust the price enough upward to take into account the fact that there is only a small chance that the deductible will be applied toward their payments. We also show that professionals in the field of insurance are less prone to such a bias. This implies that a policy with a deductible priced according to the true expected payments may seem overpriced  to the insured and therefore may not be purchased. Since the values of full coverage policies are not underestimated the insured may find them as relatively better deals .