Volume 8, Issue 4

ABSTRACT Biological processes are controlled automatically. Registration of signals and measuring their relative strength is hence a key problem. Receptors may be relatively simple or complex. The complexity is the direct response to ambiguity of signals. If there is however a common feature of diverse signals a construction of generic receptor mechanism is usually observed. Combinatorial technique is commonly used in biological systems to decrease the complexity in reception of highly ambiguous signals.

ABSTRACT Lactoferrin (Lf) - member of the transferrin family of proteins responsible for many different functions in the body of mammals participates in regulation of free iron level in the body fluids making the protein bacteriostatic. The main goal of studies was to test the suitability of molecular dynamic simulation to study structural changes in the tertiary structure of lactoferrin. According to ConSurf Server analysis one of the most conservative amino acids was found not only in iron- but also in carbohydrates- binding pockets which may suggest a significant impact of carbohydrates on the functions performed by lactoferrin. Pocket-Finder program applied to find iron-binding pockets revealed the potential Fe binding area. The stability of the ligand deprived protein was verified performing the 50 ns dynamic simulation using the Gromacs program. The tertiary structure changes during the simulation were observed in N-lob solely. No structural changes were observed in C-lob iron-binding pocket.

ABSTRACT The terms like e-science, e-poster or e-health are nowadays commonly used. Special disciplines allowing fast development in these fields of science are commonly available. This paper presents e-paper [1] powered by the Collage Authoring Environment [2] e-publication system which is backed by the GridSpace2 [3] distributed computing platform. This e-publication in a form of WWW page, apart from the traditional textual and graphical content, embeds an on-line software tool for the analysis of the 3-D structure of protein based on the hydrophobicity distribution in protein body. The tool uses GridSpace2 platform in order to carry out computations on the PL-Grid [4] high-performance computing infrastructure. This work shows how this specific epublication was accomplished utilizing above mentioned already existing information technologies and e-infrastructure The tool employs the model called “fuzzy oil drop” that assumes the hydrophobicity distribution in proteins being in form of 3-D Gauss function. The protein of the hydrophobicity core structure accordant with the model with all hydrophobic residues buried in the central part of the protein body and hydrophilic residues exposed toward the water environment could be the protein very well soluble although representing no any form of activity. This is why the observed discrepancies between idealized and observed hydrophobicity distribution is presented in form of ΔH̃_i profile revealing the localization of residues representing local hydrophobicity excess as well as local hydrophobicity deficiency. The distribution of these discrepancies appeared to be specific and function related. The e-publication makes available the tool to calculate the ΔH̃_i profile of any protein under consideration. The interpretation of the final results is specific for particular protein.

ABSTRACT This paper focuses on finding the most efficinet way of performing local and remote computations with web application based on ActionScript language. Tests involve comparsion of several scenarions which uses pure ActionScript, ActionScript with Alchemy project and ActionScript connecting with C application over AMF protocol and with FileReference class.

ABSTRACT Color is not a physical quantity of an object. It cannot be measured. We can only measure reflectance, i.e. the amount of light reflected for each wavelength. Nevertheless, we attach colors to the objects around us. A human observer perceives colors as being approximately constant irrespective of the illuminant which is used to illuminate the scene. Colors are a very important cue in everyday life. They can be used to recognize or distinguish different objects. Currently, we do not yet know how the brain arrives at a color constant or approximately color constant descriptor, i.e. what computational processing is actually performed by the brain. What we need is a computational description of color perception in particular and color vision in general. Only if we are able to write down a full computational theory of the visual system then we have understood how the visual system works. With this contribution, a computational model of color perception is presented. This model is much simpler compared to previous theories. It is able to compute a color constant descriptor even in the presence of spatially varying illuminants. According to this model, the cones respond approximately logarithmic to the irradiance entering the eye. Cells in V1 perform a change of the coordinate system such that colors are represented along a red-green, a blue-yellow and a black-white axis. Cells in V4 compute local space average color using a resistive grid. The resistive grid is formed by cells in V4. The left and right hemispheres are connected via the corpus callosum. A color constant descriptor which is presumably used for color based object recognition is computed by subtracting local space average color from the cone response within a rotated coordinate system.

ABSTRACT The paper presents an application of the Lopot-plot, which compares the timeaveraged concentration (TAC) and the time-averaged deviation (TAD) of the weekly dialysis cycle, to comprise the results of intensive computational study. The presented case is based on 420 one-week-cycle simulations to verify the consequences implied by the change of the treatments schedule from nonuniformly to uniformly distributed over the week. The concept of steady state is explained and utilized to obtain periodical runs of the urea concentration. The presented graphs encouragingly indicate the potential of such plots in presenting results of multivariable intensive computations that should be advisably performed during the planning process of hemodialysis treatment.