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Zeitschrift für Informatik und Systembiologie

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Volumen 3, Ausgabe 4 (2010)

Forschungsartikel

Bioinformatic Approach for the Identification of Hepatitis B Viral Insert in The Exon Region of Human Genome

P. Pandarinath, M. Shashi and A. Appa Rao

Hepatitis B viral sequence was downloaded from NCBI Tax Browser and scanned against complete genome of Homo sapiens for the presence of possible viral inserts in human genome. The alignments which showed more than 25-30 residues, 90-100 % identities and localization in the exon regions were only considered. The results from the computational analysis revealed that Hepatitis B virus resulted in viral segment inserted in the exon region of human genome.

Forschungsartikel

Solver Independent Modelling of Combinatorial and Optimization Problems

Reza Rafeh

Combinatorial optimization problems appear in many real life applications as timetabling, planning and scheduling. However, they are often NP-hard. This means that there is no general and efficient algorithm for solving them. Modern approaches for tackling combinatorial and optimization problems divide the task into two major tasks: modeling and solving. Modelling means finding a proper formulation of the problem while solving means finding the solution of the problem. The most well-known modeling tools are: constraint programming languages, constraint libraries, (mathematical) modelling languages and specification languages. Modelling languages provide the most high-level practical level of modelling for modellers. There are some known solving techniques to tackle such problems of which the most popular ones are: mathematical methods, constraint programming and local search. Each technique has its own advantages and disadvantages and for a given problem it is unclear at the beginning which technique gives us the best result. Current modeling languages are tied to a specific solving technique. In this paper, we show how the modeling language Zinc can automatically map a conceptual model into corresponding low level model suitable for one of the aforementioned solving techniques.

Forschungsartikel

Effect of Flap Mutation I54L/M in Inhibition of Human Immunodeficiency Virus Type 1 Protease: Relationship to Drug Resistance

Rituraj Purohit and Rao Sethumadhavan

The HIV-1 protease enzyme is one of the prime and an utmost essentially important target towards the HIV therapy. However, one of the most complex mechanisms found in this enzyme is that, it produces resistance toward most of the drugs due to mutational changes, but still maintains activity with their natural substrates. This work focuses on mechanism of Darunavir resistance HIV-1 protease flap mutant I54M and I54L. To gain insight into why mutations confer such resistance, Docking analysis, binding energetics analysis and Molecular Dynamics simulations in explicit solvent were performed on drug resistant mutants and native HIV-1 protease. The flap mutation I54M and I54L lowers the binding affinity of Darunavir by altering the position of binding site residues in 3D space. It decreases the electrostatic and van der waals interaction energy and further reduction in total receptor-ligand interaction energy. In Darunavir resistance, the contribution of I54M mutant was more than I54L mutant. The results summarized in this paper emphasize the importance of shape complementarity and flexibility of binding residues in drug design.

Forschungsartikel

Study of Left Ventricle Pressure-Volume Loops in Renal Stenosis Case Using Equivalent Electrical Circuit

Mona Abdolrazaghi, Mahdi Navidbakhsh, Kamran Hassani and Farhad Izadi

In this study, we have obtained the cardiac pressure-volume graphs of Renal Artery Stenosis disease with different stenotic values, moreover, the graphs are compared with normal condition. The cardiovascular Electronic circuit includes 42 elements including main arterial vessels. We have extracted the vessels geometrical data from the medical texts. The calculated pressure drops and the compliance variations of artery stenosis are applied to the electronic model. Then, the graphs have been obtained for different stenotic values (20%, 50%, 70%, and 90%) using ORCAD/ MATLAB software. Finally, the results of modeling have been discussed and compared with the clinical data. The results of stenosis show that hypertension could be a symptom of the disease. When the rate of stenosis increases the blood pressure rises. This study is a tool for students in order to see the cardiovascular system operation in normal condition or abnormal.

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