615 research outputs found
Modified Genetic Algorithms for Cellular Automata Design
Tato práce se zabývá evolučním návrhem přechodové funkce celulárního automatu řešícího zvolenou úlohu. Jsou v ní popsány celulární automaty, evoluční algoritmy a alternativní forma zápisu pravidel přechodové funkce vhodná pro evoluční návrh - podmínková pravidla. Dále je zvolen problém řešený celulárním automatem a prezentovány pokusy takový automat navrhnout genetickým algoritmem. Pokračuje se optimalizací parametrů algoritmu, hledáním jeho možných problémů a navržením modifikací řešících je. Pozitivní vlyv těchto modifikací je následně zhodnocen na několika experimentech.This bachelor’s thesis aims to examine possibilities of designing a transition function enabling a cellular automaton to solve a given problem using a genetic algorithm. It contains an introduction to cellular automata, evolution algorithms and conditionally matching rules, a method of descripting a transition function suitable for evolutionary development. A set of experiments is conducted using the standard version of genetic algorithms to determine its optimal configuration. Additionally, modifications of this standard algorithm are proposed, effect of which on the algorithm’s performance is then evaluated by further experiments.
LPG Alternative Fuel Cars
Obsahom bakalárskej práce je prehľad posledného vývoja v oblasti alternatívnych pohonov na LPG. Práca sa zaoberá zložením a charakteristickými vlastnosťami LPG, prehľadom a popisom funkcií komponentov LPG, prestavbami automobilu na pohon LPG, použitím LPG systémov podľa úrovne vyspelosti motora, ekologickými aspektmi a vplyvmi LPG na opotrebenie motorových komponentov. Záver zhrňuje dôležité poznatky a vlastné zkušenosti o pohone LPG a zachytáva ekonomickú stránku prevádzky vozidiel na LPG.This Bachelor's thesis contents the very last development in field of LPG alternative fuel cars. The thesis deals with constitution and characteristic properties of LPG, survey and description of various LPG components, LPG conversion, the use of a specific LPG system, according to engine technological level, ecologic aspects and LPG influence on engine components wear. The conclusion contain important knowledge and very own expirience in matter of LPG conversion and its economic features.
The intron-containing gene for yeast profilin (PFY) encodes a vital function
The gene coding for profilin (PFY), an actin-binding protein, occurs as a single copy in the haploid genome of Saccharomyces cerevisiae and is required for spore germination and cell viability. Displacement of one gene copy in a diploid cell by a nonfunctional allele is recessively lethal: tetrad analysis yields only two viable spores per ascus. The PFY gene maps on chromosome XV and is linked to the ADE2 marker. The primary transcript of about 1,000 bases contains an intron of 209 bases and is spliced into a messenger of about 750 bases. The intron was identified by comparison with a cDNA clone, which also revealed the 3' end of the transcript. The 5' end of the mRNA was mapped by primer elongation. The gene is transcribed constitutively and has a coding capacity for a protein of 126 amino acids. The deduced molecular weight o
Overexpression of the urokinase receptor splice variant uPAR-del4/5 in breast cancer cells affects cell adhesion and invasion in a dose-dependent manner and modulates transcription of tumor-associated genes
mRNA levels of the urokinase receptor splice variant uPAR-del4/5 are associated with prognosis in breast cancer. Its overexpression in cancer cells affects tumor biologically relevant processes. In the present study, individual breast cancer cell clones displaying low vs. high uPAR-del4/5 expression were analyzed demonstrating that uPAR-del4/5 leads to reduced cell adhesion and invasion in a dose-dependent manner. Additionally, matrix metalloproteinase-9 (MMP-9) was found to be strongly upregulated in uPAR-del4/5 overexpressing compared to vector control cells. uPAR-del4/5 may thus play an important role in the regulation of the extracellular proteolytic network and, by this, influence the metastatic potential of breast cancer cells
Cyclo19,31[D-Cys19]-uPA19-31 is a potent competitive antagonist of the interaction of urokinase-type plasminogen activator with its receptor (CD87)
Urokinase-type plasminogen activator (uPA) represents a central molecule in pericellular proteolysis and is implicated in a variety of physiological and pathophysiological processes such as tissue remodelling, wound healing, tumor invasion, and metastasis. uPA binds with high affinity to a specific cell surface receptor, uPAR (CD87), via a well defined sequence within the N-terminal region of uPA (uPA(19-31)). This interaction directs the proteolytic activity of uPA to the cell surface which represents an important step in tumor cell proliferation, invasion, and metastasis. Due to its fundamental role in these processes, the uPA/uPAR-system has emerged as a novel target for tumor therapy. Previously, we have identified a synthetic, cyclic, uPA-derived peptide, cyclo(19,31)uPA(19-31), as a lead structure for the development of low molecular weight uPA-analogues, capable of blocking uPA/uPAR-interaction {[}Burgle et al., Biol. Chem. 378 (1997), 231-237]. We now searched for peptide variants of cyclo(19,31)uPA(19-31) with elevated affinities for uPAR binding. Among other tasks, we performed a systematic D-amino acid scan of quPA(19-31), in which each of the 13 L-amino acids was individually substituted by the corresponding D-amino acid. This led to the identification of cyclo(19,31) {[}D-Cys(19)]-uPA(19-31) as a potent inhibitor of uPA/uPAR-interaction, displaying only a 20 to 40-fold lower binding capacity as compared to the naturally occurring uPAR-ligands uPA and its amino-terminal fragment. Cyclo(19,31)[D-Cys(19)]-uPA(19-31) not only blocks binding of uPA to uPAR but is also capable of efficiently displacing uPAR-bound uPA from the cell surface and to inhibit uPA-mediated, tumor cell-associated plasminogen activation and fibrin degradation. Thus, cyclo(19,31)[D-Cys(19)]-uPA(19-31) represents a promising therapeutic agent to significantly affect the tumor-associated uPA/uPAR-system
A yeast gene (BLH1) encodes a polypeptide with high homology to vertebrate bleomycin hydrolase, a family member of thiol proteinases
We have purified bleomycin hydrolase from yeast (molecular mass 55 000 Da). Using protein sequence-derived degenerate oligonucleotide primers and amplification by polymerase chain reaction, the yeast gene BLH1 was isolated and characterized. The deduced amino acid sequence (483 amino acids) exhibits surprisingly high homology to vertebrate bleomycin hydrolase (43% identical residues and 22% conserved exchanges). It contains three blocks of sequences found conserved in other members of the thiol proteinase family and thought to be associated with the catalytic centre. BLH1 is non-essential under all growth conditions tested. However, in the presence of 3.5 mg bleomycin/ml medium wild-type cells have a slight growth advantage compared to blh1 mutant cells
Novel bi- and trifunctional inhibitors of tumor-associated proteolytic systems
Serine proteases, cysteine proteases, and matrix metalloproteinases (MMPs) are involved in cancer cell invasion and metastasis. Recently, a recombinant bifunctional inhibitor (chCysuPA(19-31)) directed against cysteine proteases and the urokinasetype plasminogen activator (uPA)/plasmin serine protease system was generated by introducing the uPA receptor (uPAR)binding site of uPA into chicken cystatin (chCysWT). In the present study, we designed and recombinantly produced multifunctional inhibitors also targeting MMPs. The inhibitors comprise the Nterminal inhibitory domain of human TIMP-1 (tissue inhibitor of matrix metalloproteinase-1) or TIMP-3, fused to chCysuPA(19-31) or chCysWT. As demonstrated by various techniques, these fusion proteins effectively interfere with all three targeted protease systems. In in vitro Matrigel invasion assays, the addition of recombinant inhibitors strongly reduced invasion of ovarian cancer cells (OVMZ-6\#8). Additionally, OVMZ 6\#8 cells were stably transfected with expression plasmids encoding the various inhibitors. Synthesis and secretion of the inhibitors was verified by a newly developed ELISA, which selectively detects the recombinant proteins. Invasive capacity of inhibitorproducing cells was significantly reduced compared to vectortransfected control cells. Thus, these novel, compact, and smallsize inhibitors directed against up to three different tumorassociated proteolytic systems may represent promising agents for prevention of tumor cell migration and metastasis
Protease inhibitors prevent plasminogen-mediated, but not pemphigus vulgaris-induced, acantholysis in human epidermis
Pemphigus is an autoimmune blistering disease of the skin and mucous membranes. It is caused by autoantibodies directed against desmosomes, which are the principal adhesion structures between epidermal keratinocytes. Binding of autoantibodies leads to the destruction of desmosomes resulting in the loss of cell-cell adhesion (acantholysis) and epidermal blisters. The plasminogen activator system has been implicated as a proteolytic effector in pemphigus. We have tested inhibitors of the plasminogen activator system with regard to their potential to prevent pemphigus-induced cutaneous pathology. In a human split skin culture system, IgG preparations of sera from pemphigus vulgaris patients caused histopathologic changes (acantholysis) similar to those observed in the original pemphigus disease. All inhibitors that were tested (active site inhibitors directed against uPA, tPA, and/or plasmin; antibodies neutralizing the enzymatic activity of uPA or tPA; substances interfering with the binding of uPA to its specific cell surface receptor uPAR) failed to prevent pemphigus vulgaris IgG-mediated acantholysis. Plasminogen-mediated acantholysis, however, was effectively antagonized by the synthetic active site serine protease inhibitor WX-UK1 or by p-aminomethylbenzoic acid. Our data argue against applying anti-plasminogen activator/anti-plasmin strategies in the management of pemphigus
Workshop synthesis: Measuring attitudes and perceptions in large scale (quantitative) surveys
This paper presents the main outcomes of the workshop A5 Measuring attitudes and perceptions in large scale (quantitative) surveys. There is a big need in the community to include more questions about psychological factors in surveys, because the travel behavior is getting more divers. The workshop discussion revealed that while there are different survey methods to capture information about the participants’ psychology, Likert scales are mainly used because they are easy to implement and to fill in. However, the reliability of the results must be assessed in light of the survey method and type of analysis. Further research is needed to combine quantitative surveys with methods to collect psychological information
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