Fluorescent carbohydrate probes for cell lectins

Fluorescein labeled carbohydrate (Glyc) probes were synthesized as analytical tools for the study of cellular lectins, i.e. SiaLe(x)-PAA-flu, Sia2-PAA-flu, GlcNAc2-PAA-flu, LacNAc-PAA-flu and a number of similar ones, with PAA a soluble polyacrylamide carrier. The binding of SiaLe(x)-PAA-flu was assessed using CHO cells transfected with E-selectin, and the binding of Sia2-PAA-flu was assessed by COS cells transfected with siglec-9. In flow cytometry assays, the fluorescein probes demonstrated a specific binding to the lectin-transfected cells that was inhibited by unlabeled carbohydrate ligands. The intense binding of SiaLe(x)-PAA-3H to the E-selectin transfected cells and the lack of binding to both native and permeabilized control cells lead to the conclusion that the polyacrylamide carrier itself and the spacer arm connecting the carbohydrate moiety with PAA did not contribute anymore to the binding. Tumors were obtained from nude mice by injection of CHO E-selectin or mock transfected cells. The fluorescent SiaLe(x)-PAA-flu probe could bind to the tumor sections from E-selectin positive CHO cells, but not from the control ones. Thus, these probes can be used to reveal specifically the carbohydrate binding sites on cells in culture as well as cells in tissue sections. The use of the confocal spectral imaging technique with Glyc-PAA-flu probes offered the unique possibility to detect lectins in different cells, even when the level of lectin expression was rather low. The confocal mode of spectrum recording provided an analysis of the probe localization with 3D submicron resolution. The spectral analysis (as a constituent part of the confocal spectral imaging technique) enabled interfering signals of the probe and intrinsic cellular fluorescence to be accurately separated, the distribution of the probe to be revealed and its local concentration to be measured.     

Order of play in strategically equivalent games in extensive form

“Can we find a pair of extensive form games that give rise to the same strategic form game such that, when played by a reasonable subject population, there is a statistically significant difference in how the games are played?” (Kreps, 1990, p. 112). And if yes, “can we organize these significant differences according to some principles that reflect recognizable differences in the extensive forms?” Both questions are answered positively by reporting results from three different experiments on public goods provision, resource dilemmas, and pure coordination games.     

Hyperfine interactions in muonium-impurity complexes in silicon

The properties of paramagnetic complexes formed by muonium located near acceptor and donor impurities in silicon are calculated using the quantum chemical methods. The calculated data are compared to the experimentally observed characteristics of normal and anomalous muonium centers.     

Quantitative Analyse

Ohne Zusammenfassung     

Allocation of an indivisible resource: Optimal control and prices

Under study is a dynamical system of economics with discrete time whose states at each moment correspond to nonnegative integer points of a two-dimensional vector space. There are two types of products and two facilities each of which can change the state of the system by random integer vectors with different collections of probabilities. By a control we understand the choice at each moment of time of one available collection of probabilities. The goal of control is to minimize the probability of leaving the positive quadrant. The question is considered of the existence of some prices that agree with an optimal control.     

Three-dimensional ionization calorimeter on the basis of scintillation fibers

A design of an ionization calorimeter in which scintillation fibers oriented in three mutually orthogonal directions are used as a detecting system is proposed. Such a device can be employed in satellite-borne experiments aimed at studying high-energy cosmic rays. This scheme makes it possible to reconstruct the primary-particle energy for any track direction, this ensuring a large geometric factor. A high spatial resolution enables one to separate the electromagnetic and hadron components by the shape of the cascade.