Biomedical subjects
Publications and source records attributed to M Gheorghe.
The paper discusses the modelling aspects of systems with dynamic processes and dynamic structure. A combination of models bringing together the benefits of two paradigms, Population P Systems and Communicating X-machines, is introduced. A simple case study is used in order to illustrate the potential of the combined use of the two methods.
The aim of this paper is to prove the suitability of a parallel distributed computational model, communicating X-machines, to simulate in a natural way a well established model of molecular computation, P systems, and to present some further benefits of the approach allowing us to check for some formal properties. A set of rules to transform any P system with symbol-objects into a communicating X-machine model is presented and a variation of temporal logic for X-machines is briefly discussed, which facilitates model checking of desired properties of the system. Finally, the benefits resulting from the transformation are discussed.
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In this paper, we present a word set generating mechanism, called cell-differentiation system, inspired by the tissue process formation in multicellular organisms, which might model some properties of evolving communities of living cells at the syntactical level. The tools utilized to model these biological phenomena belong to the formal language theory. In this context chromosomal mutations are defined as operations on strings and the differentiation according to the control of gene expression is represented by some random-context conditions in formal languages. In the presented formal framework we prove that in a simplified form of this formalism, with only one cell-type which is regular, one single cell and no mitosis involved, the problem of establishing whether or not the set of vectors of integers indicating the number of cells in each population, is finite, linear or semilinear, is recursively undecidable. However, one can algorithmically decide whether or not a cell-differentiation system of finite cell-type can produce a specific generation of cells.
In this paper the behaviour of a bee colony is modelled as society of communicating agents acting in parallel and synchronising their behaviour. Two computational approaches for defining the agents behaviour are introduced and compared. Their common features as well as the complementary aspects making them suitable for merging together into a more complex model.
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76 Str.pneumoniae strains isolated from different clinical disease forms were studied for the sensitivity to antimicrobial drugs using the diffusimetric method and the dilution in agar method (MIC to penicillin). The results revealed that 44.74% of pneumococci were sensitive to penicillin, the remaining pneumococci being resistant; 18.42% showed a high resistance (MIC > or = 2 micrograms/ml). A close relationship was seen between sensitivity to penicillin on the one hand and the Pneumococcus origin and serotype on the other. As concerning the multiresistance to antimicrobial drugs, 47.4% of the strains presented resistance to > or = antibiotics belonging to different classes, the most frequent resistance pattern being P, E, Te, SxT. The most active antimicrobial drugs were vancomycin, amoxiclave, rifampicin, followed by ceftriaxone and amoxicillin.