Motion of a liquid droplet in a capillary under the action of static force and an acoustic field

We consider the motion of a liquid droplet inside a capillary of a porous medium under the action of a static force and an acoustic field. We derive the equation of motion of the droplet in the capillary and analyze numerically its solution. We show that the vibration attenuates the influence of the capillary force. Due to the effect of the acoustic field, the droplet motion in a capillary of constant cross-section starts at a lower value of the static force, and the reciprocal velocity of the droplet increases. Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 43, No. 2, pp. 155–161, February 2000.     

Fluorescence energy transfer-sensitized photobleaching of a fluorescent label as a tool to study donor-acceptor distance distributions and dynamics in protein assemblies: studies of a complex of biotinylated IgM with streptavidin and aggregates of concanavalin A

A photokinetic method of detection of fluorescence resonance energy transfer (FRET) between special fluorescent labels is applied to study time-averaged spatial distribution of labeled proteins in protein assemblies. Prolonged irradiation of a sample at the absorption maximum of the energy donor initiates FRET-sensitized fluorescence photobleaching of the energy acceptor label, which was monitored by steady-state fluorimetric measurements. Kinetics of the acceptor photobleaching and kinetics of decreasing the efficiency of FRET from donors to unbleached acceptors were determined. The FRET efficiency was found from measuring sensitization of acceptor fluorescence. Analysis of the photokinetic data permits to estimate the time-averaged distribution of acceptors on donor-acceptor distances in the range of characteristic distances of FRET. Dynamic processes influencing donor-acceptor distances can be also investigated by the method. Application of the method is demonstrated by the studies of a complex of biotinylated IgM with streptavidin and aggregates composed of concanavalin A and sodium dodecyl sulphate. A new thiadicarbocyanine dye was used as the acceptor label. R-phycoerythrin and tetramethylrhodamine isothiocyanate were the donor labels. In the IgM-streptavidin complex, 16% of acceptors most contributed to FRET provided 90% of FRET efficiency, whereas acceptors made about the same time-averaged contribution to FRET in the concanavalin A aggregates.     

The Robust Set Covering Problem with interval data

We study the Set Covering Problem with uncertain costs. For each cost coefficient, only an interval estimate is known, and it is assumed that each coefficient can take on any value from the corresponding uncertainty interval, regardless of the values taken by other coefficients. It is required to find a robust deviation (also called minmax regret) solution. For this strongly NP-hard problem, we present and compare computationally three exact algorithms, where two of them are based on Benders decomposition and one uses Benders cuts in the context of a Branch-and-Cut approach, and several heuristic methods, including a scenario-based heuristic, a Genetic Algorithm, and a Hybrid Algorithm that uses a version of Benders decomposition within a Genetic Algorithm framework.     

Nash equilibria in competitive project scheduling

We consider the problem of scheduling activities of a project by a firm that competes with another firm that has to perform the same project. The profit that a firm gets from each activity depends on whether the firm finishes the activity before or after its competitor. It is required to find a Nash equilibrium solution or show that no such solutions exist. We present a structural characterization of Nash equilibrium solutions, and a low order polynomial algorithm for the problem.     

The competitive salesman problem on a network: a worst-case approach

We provide a complexity analysis of the problem of optimal routing of a server on a transportation network in the presence of a competing server. The server that reaches a node first gets the profit from the node. The objective is to maximize the worst-case profit.     

Effect of Gadolinium(III) Ions on the Phase Behaviour of Dimyristoylphosphatidyl Serine Multilamellar Liposomes

The effects of low concentrations of Gd³⁺ on dimyristoylphosphatidyl serine (DMPS) multilamellar liposomes were studied by differential scanning calorimetry (DSC). At low ionic strength merely a shifting upscale and a broadening of the main transition peak were observed. At high ionic strength, Gd³⁺ provoked the formation of a few clearly-discernible high-temperature components. Increase of the Gd level affected the relative intensities of these components, whereas the corresponding midpoints and half-widths remained unchanged. At the same time, in the presence of about 20 mol% dimyristoylphosphatidyl choline in the mixture with DMPS, similar secondary peaks appeared, but their positions were markedly shifted, to extents dependent on the Gd concentration. Interpretation of the data in terms of two-dimensional crystal structures is suggested. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phase method of crosswell profiling using coherent SH waves

The results of an experiment on crosswell profiling using the coherent downhole source of SH waves are presented. Seismic records were obtained during stationary disposal of the source and varying depths of the vector receiver position. The source coherence made it possible to accumulate signals, thus sub-stantially improving the quality of seismograms and measuring phases. These procedures allowed low-contrasting boundaries between layers to be distinguished. The performed digital modeling confirmed the measurement results.     

Approximation algorithm for the on-line multi-customer two-level supply chain scheduling problem

A manufacturer has to process jobs released on-line and deliver them to customers. Preemption is allowed. Jobs are grouped into batches for delivery. The sum of the total flow time and the total delivery cost is minimized. Deliveries to different customers cannot be combined. We present an on-line algorithm with the competitive ratio bounded by 3+α$3+\alpha$, where α$\alpha$ is the ratio of the largest processing time to the smallest processing time.