The Experts below are selected from a list of 157026 Experts worldwide ranked by ideXlab platform
Hirosuke Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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Representative sequence selection in unsupervised anomaly detection using spectrum kernel with Theoretical Parameter setting
2010 International Conference on Machine Learning and Cybernetics, 2010Co-Authors: Stefan Jan Skudlarek, Hirosuke YamamotoAbstract:Unsupervised anomaly detection is an important topic of data mining research, especially with respect to non-numerical sequence data. However, the majority of previous algorithms features empirical Parameter selection. The contribution of this study is twofold: First, we show how the Akaike Information Criterion can be used to set the Parameter of the spectrum kernel. Second, a distance-based algorithm for one-class unsupervised anomaly detection is presented. The algorithm uses the distance matrix of the data to select a sequence representative of the normal class by means of robust statistics. The proposed algorithm is applied to two kinds of sequence data, showing its suitability.
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ICMLC - Representative sequence selection in unsupervised anomaly detection using spectrum kernel with Theoretical Parameter setting
2010 International Conference on Machine Learning and Cybernetics, 2010Co-Authors: Stefan Jan Skudlarek, Hirosuke YamamotoAbstract:Unsupervised anomaly detection is an important topic of data mining research, especially with respect to non-numerical sequence data. However, the majority of previous algorithms features empirical Parameter selection. The contribution of this study is twofold: First, we show how the Akaike Information Criterion can be used to set the Parameter of the spectrum kernel. Second, a distance-based algorithm for one-class unsupervised anomaly detection is presented. The algorithm uses the distance matrix of the data to select a sequence representative of the normal class by means of robust statistics. The proposed algorithm is applied to two kinds of sequence data, showing its suitability.
L’ubica Horáková - One of the best experts on this subject based on the ideXlab platform.
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Novel quercetin derivatives in treatment of peroxynitrite-oxidized SERCA1
Molecular and Cellular Biochemistry, 2014Co-Authors: Petronela Žižková, Dušan Blaškovič, Magdaléna Májeková, L’ubomír Švorc, Lucia Račková, L’ubica Ratkovská, Miroslav Veverka, L’ubica HorákováAbstract:Sarco/endoplasmic reticulum calcium ATP-ase (SERCA) is regulated by low concentrations of peroxynitrite and inhibited by high levels, as indicated in human diseases. We studied quercetin ( Q ) and its novel derivatives monochloropivaloylquercetin (MPQ) and chloronaphthoquinonequercetin (CHQ) as agents with expected preventive properties against peroxynitrite-induced SERCA impairment. Q and MPQ protected the SERCA1 against peroxynitrite induced activity decrease, while CHQ potentiated the inhibitory effect of peroxynitrite. Quercetin derivatives were found to be weaker antioxidants compared with Q , as indicated by their ability to scavenge peroxynitrite and prevent of SERCA1 carbonylation, both decreasing in the order ( Q > MPQ > CHQ). Quantum-chemical values of Theoretical Parameter E _HOMO also indicated lower antioxidant capacities for MPQ and CHQ. Prooxidant properties estimated by calculations of frontier molecular orbitals ( E _LUMO) correlated with experimentally determined SH-group decrease induced by the compounds studied. Both methods showed a decrease of prooxidant properties as follows: CHQ > MPQ > Q . In addition, experimentally measured half-wave potentials indicated stronger prooxidant properties of quercetin derivatives as compared to Q . More expressive alterations of conformation in the transmembrane region of SERCA1 induced by quercetin derivatives, as compared with Q , may at least partially correlate with their higher lipophilicities. The protective effects of Q and MPQ on different isoforms of SERCA activity may be useful in prevention and treatment of inflammation or muscle diseases. The inhibitory effect of CHQ on SERCA isoforms may be beneficial in therapeutic approaches aimed at anti-tumor treatment.
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Novel quercetin derivatives in treatment of peroxynitrite-oxidized SERCA1
Molecular and Cellular Biochemistry, 2014Co-Authors: Petronela Žižková, Dušan Blaškovič, Magdaléna Májeková, L’ubomír Švorc, Lucia Račková, L’ubica Ratkovská, Miroslav Veverka, L’ubica HorákováAbstract:Sarco/endoplasmic reticulum calcium ATP-ase (SERCA) is regulated by low concentrations of peroxynitrite and inhibited by high levels, as indicated in human diseases. We studied quercetin ( Q ) and its novel derivatives monochloropivaloylquercetin (MPQ) and chloronaphthoquinonequercetin (CHQ) as agents with expected preventive properties against peroxynitrite-induced SERCA impairment. Q and MPQ protected the SERCA1 against peroxynitrite induced activity decrease, while CHQ potentiated the inhibitory effect of peroxynitrite. Quercetin derivatives were found to be weaker antioxidants compared with Q , as indicated by their ability to scavenge peroxynitrite and prevent of SERCA1 carbonylation, both decreasing in the order ( Q > MPQ > CHQ). Quantum-chemical values of Theoretical Parameter E _HOMO also indicated lower antioxidant capacities for MPQ and CHQ. Prooxidant properties estimated by calculations of frontier molecular orbitals ( E _LUMO) correlated with experimentally determined SH-group decrease induced by the compounds studied. Both methods showed a decrease of prooxidant properties as follows: CHQ > MPQ > Q . In addition, experimentally measured half-wave potentials indicated stronger prooxidant properties of quercetin derivatives as compared to Q . More expressive alterations of conformation in the transmembrane region of SERCA1 induced by quercetin derivatives, as compared with Q , may at least partially correlate with their higher lipophilicities. The protective effects of Q and MPQ on different isoforms of SERCA activity may be useful in prevention and treatment of inflammation or muscle diseases. The inhibitory effect of CHQ on SERCA isoforms may be beneficial in therapeutic approaches aimed at anti-tumor treatment.
Hongyu Zhang - One of the best experts on this subject based on the ideXlab platform.
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Theoretical elucidation on activity differences of ten flavonoid antioxidants
Acta Biochimica et Biophysica Sinica, 2000Co-Authors: Hongyu Zhang, Dezhan ChenAbstract:: Theoretical methods including structure-activity relationships (SAR) and quantum chemical calculations were used to elucidate the free radical scavenging activity differences of 10 flavonoid antioxidants. SAR could give a qualitative explanation on the antioxidant activity differences. And a further elucidation was performed by a Theoretical Parameter, the difference of heat of formation between antioxidant and its free radical (deltaHOF), calculated by Austin Model 1 (AM1) method. Besides, deltaHOF showed a linear correlationship with the logarithm of the relative antioxidant efficiency (lgRAE, r = 0.7523), indicating that the Theoretical methods were effective to elucidate the differences of antioxidant activity. On the other hand, the ineffectiveness of another Theoretical Parameter, the highest occupied molecular orbit (HOMO) energy level, was verified further.
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Selection of Theoretical Parameter characterizing scavenging activity of antioxidants on free radicals
Journal of the American Oil Chemists' Society, 1998Co-Authors: Hongyu ZhangAbstract:Semiempirical quantum chemistry method Austin Model 1 (AM1) was employed to calculate the Theoretical Parameters of 15 antioxidants. Such Parameters as bond order, bond length, and the difference of heat of formation (ΔHOF) between the antioxidant and its phenolic free radicals were obtained. Through correlating with previous experimental results ΔHOF was proven to be a proper Parameter (r=0.9491) to characterize the free radical-scavenging activity of antioxidants, but bond order and bond length were not able to represent the antioxidant’s ability to scavenge free radicals. By comparing the results calculated by different semiempirical methods, including AM1, Modified Neglect of Diatomic Overlap, and Parametric Method 3, AM1 was found to be the best for calculating ΔHOF.
Stefan Jan Skudlarek - One of the best experts on this subject based on the ideXlab platform.
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Representative sequence selection in unsupervised anomaly detection using spectrum kernel with Theoretical Parameter setting
2010 International Conference on Machine Learning and Cybernetics, 2010Co-Authors: Stefan Jan Skudlarek, Hirosuke YamamotoAbstract:Unsupervised anomaly detection is an important topic of data mining research, especially with respect to non-numerical sequence data. However, the majority of previous algorithms features empirical Parameter selection. The contribution of this study is twofold: First, we show how the Akaike Information Criterion can be used to set the Parameter of the spectrum kernel. Second, a distance-based algorithm for one-class unsupervised anomaly detection is presented. The algorithm uses the distance matrix of the data to select a sequence representative of the normal class by means of robust statistics. The proposed algorithm is applied to two kinds of sequence data, showing its suitability.
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ICMLC - Representative sequence selection in unsupervised anomaly detection using spectrum kernel with Theoretical Parameter setting
2010 International Conference on Machine Learning and Cybernetics, 2010Co-Authors: Stefan Jan Skudlarek, Hirosuke YamamotoAbstract:Unsupervised anomaly detection is an important topic of data mining research, especially with respect to non-numerical sequence data. However, the majority of previous algorithms features empirical Parameter selection. The contribution of this study is twofold: First, we show how the Akaike Information Criterion can be used to set the Parameter of the spectrum kernel. Second, a distance-based algorithm for one-class unsupervised anomaly detection is presented. The algorithm uses the distance matrix of the data to select a sequence representative of the normal class by means of robust statistics. The proposed algorithm is applied to two kinds of sequence data, showing its suitability.
Petronela Žižková - One of the best experts on this subject based on the ideXlab platform.
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Novel quercetin derivatives in treatment of peroxynitrite-oxidized SERCA1
Molecular and Cellular Biochemistry, 2014Co-Authors: Petronela Žižková, Dušan Blaškovič, Magdaléna Májeková, L’ubomír Švorc, Lucia Račková, L’ubica Ratkovská, Miroslav Veverka, L’ubica HorákováAbstract:Sarco/endoplasmic reticulum calcium ATP-ase (SERCA) is regulated by low concentrations of peroxynitrite and inhibited by high levels, as indicated in human diseases. We studied quercetin ( Q ) and its novel derivatives monochloropivaloylquercetin (MPQ) and chloronaphthoquinonequercetin (CHQ) as agents with expected preventive properties against peroxynitrite-induced SERCA impairment. Q and MPQ protected the SERCA1 against peroxynitrite induced activity decrease, while CHQ potentiated the inhibitory effect of peroxynitrite. Quercetin derivatives were found to be weaker antioxidants compared with Q , as indicated by their ability to scavenge peroxynitrite and prevent of SERCA1 carbonylation, both decreasing in the order ( Q > MPQ > CHQ). Quantum-chemical values of Theoretical Parameter E _HOMO also indicated lower antioxidant capacities for MPQ and CHQ. Prooxidant properties estimated by calculations of frontier molecular orbitals ( E _LUMO) correlated with experimentally determined SH-group decrease induced by the compounds studied. Both methods showed a decrease of prooxidant properties as follows: CHQ > MPQ > Q . In addition, experimentally measured half-wave potentials indicated stronger prooxidant properties of quercetin derivatives as compared to Q . More expressive alterations of conformation in the transmembrane region of SERCA1 induced by quercetin derivatives, as compared with Q , may at least partially correlate with their higher lipophilicities. The protective effects of Q and MPQ on different isoforms of SERCA activity may be useful in prevention and treatment of inflammation or muscle diseases. The inhibitory effect of CHQ on SERCA isoforms may be beneficial in therapeutic approaches aimed at anti-tumor treatment.
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Novel quercetin derivatives in treatment of peroxynitrite-oxidized SERCA1
Molecular and Cellular Biochemistry, 2014Co-Authors: Petronela Žižková, Dušan Blaškovič, Magdaléna Májeková, L’ubomír Švorc, Lucia Račková, L’ubica Ratkovská, Miroslav Veverka, L’ubica HorákováAbstract:Sarco/endoplasmic reticulum calcium ATP-ase (SERCA) is regulated by low concentrations of peroxynitrite and inhibited by high levels, as indicated in human diseases. We studied quercetin ( Q ) and its novel derivatives monochloropivaloylquercetin (MPQ) and chloronaphthoquinonequercetin (CHQ) as agents with expected preventive properties against peroxynitrite-induced SERCA impairment. Q and MPQ protected the SERCA1 against peroxynitrite induced activity decrease, while CHQ potentiated the inhibitory effect of peroxynitrite. Quercetin derivatives were found to be weaker antioxidants compared with Q , as indicated by their ability to scavenge peroxynitrite and prevent of SERCA1 carbonylation, both decreasing in the order ( Q > MPQ > CHQ). Quantum-chemical values of Theoretical Parameter E _HOMO also indicated lower antioxidant capacities for MPQ and CHQ. Prooxidant properties estimated by calculations of frontier molecular orbitals ( E _LUMO) correlated with experimentally determined SH-group decrease induced by the compounds studied. Both methods showed a decrease of prooxidant properties as follows: CHQ > MPQ > Q . In addition, experimentally measured half-wave potentials indicated stronger prooxidant properties of quercetin derivatives as compared to Q . More expressive alterations of conformation in the transmembrane region of SERCA1 induced by quercetin derivatives, as compared with Q , may at least partially correlate with their higher lipophilicities. The protective effects of Q and MPQ on different isoforms of SERCA activity may be useful in prevention and treatment of inflammation or muscle diseases. The inhibitory effect of CHQ on SERCA isoforms may be beneficial in therapeutic approaches aimed at anti-tumor treatment.