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1.
Heliyon ; 8(11): e11388, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36387555

ABSTRACT

In this paper, a closed-form analytical solution of option price under the Bi-Heston model is derived. Through empirical analysis, the advantages and disadvantages of the parametric pricing model are compared and analysed with those of the non-parametric model. The analysis shows that: (1) the parametric pricing model significantly outperforms the machine learning model in terms of in-sample pricing effects, while the Bi-Heston model slightly outperforms the Heston model. (2) In terms of out-of-sample pricing, the machine learning model is inferior to the parametric model for call options, while the Bi-Heston model is significantly better than the other two models for put options, and the other two models are similar. (3) In the robustness analysis of the three pricing models, the machine learning model shows strong instability, while the Bi-Heston model shows a more stable side.

2.
Bioorg Med Chem ; 17(13): 4274-9, 2009 Jul 01.
Article in English | MEDLINE | ID: mdl-19481940

ABSTRACT

2-Hydrazinyl-1,4,5,6-tetrahydropyrimidin-5-ol dihydrochloride 2, as well as 2-hydrazinyl-4,5-dihydro-1H-imidazole dihydrochloride 1, was synthesized as metal-free DNA cleaving agent. Agarose gel electrophoresis was used to assess the plasmid pUC 19 DNA cleavage activities in the presence of 1 and 2. DNA cleavage efficiency of 2 exhibits remarkable increases compared with its corresponding non-hydroxy compound 1. Kinetic data of DNA cleavage promoted by 2 fit to the Michaelis-Menten-type equation with k(max) of 0.0378+/-0.0013 h(-1) giving 10(6)-fold rate acceleration over uncatalyzed DNA. The acceleration is driven by the spatial proximity of the nucleophilic hydroxy group and the electrophilic activation for the phosphodiester by the ammonium and/or guanidinium groups. In vitro cytotoxic activities toward Hela cells and human leukemia HL-60 cells were also examined, and 2 exhibits stronger cytotoxic activities than 1.


Subject(s)
Cell Proliferation/drug effects , DNA Cleavage/drug effects , DNA/metabolism , Hydrazines/chemical synthesis , Hydrazines/pharmacology , Pyrimidines/chemical synthesis , Pyrimidines/pharmacology , DNA/analysis , Drug Discovery , Electrophoresis, Agar Gel , HL-60 Cells , HeLa Cells , Humans , Kinetics , Models, Molecular , Molecular Structure , Osmolar Concentration , Plasmids/analysis , Plasmids/metabolism
3.
Bioconjug Chem ; 19(9): 1840-8, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18720980

ABSTRACT

Novel cleft molecule pyridine-2,6-dicarboxamide appending two guanidinoethyl group side arms (Gua) was synthesized. The interactions of the cleft molecule in the absence of copper(II) (Gua) or in the presence of copper(II) (Cu2+-Gua) with calf thymus DNA were studied by fluorescence and CD spectroscopy. The results indicate that the DNA binding affinity of Cu2+-Gua is stronger than that of Gua, and the binding constants of Cu2+-Gua and Gua are 1.61 x 10(6) M(-1) and 2.86 x 10(5) M(-1), respectively. Agarose gel electrophoresis was used to assess the plasmid pUC 19 DNA cleavage activities in the presence of Gua and Cu2+-Gua. Kinetic data of DNA cleavage promoted by Cu2+-Gua under physiological conditions fit a saturation kinetic profile with k(max) of 0.0173 +/- 0.0011 h(-1), which gave a aproximately 10(6)-fold rate acceleration over uncatalyzed supercoiled DNA, while the catalyst concentration is lower than 0.0625 mM. The hydrolysis pathway was proposed as the possible mechanism for DNA cleavage promoted by Cu2+-Gua. The acceleration is due to efficient cooperative catalysis of the copper cation center and the functional groups (bis(guanidinium) groups).


Subject(s)
Copper/chemistry , DNA Cleavage , DNA/metabolism , Guanidine/analogs & derivatives , Pyridones/chemical synthesis , Catalysis , Cations, Divalent/chemistry , Circular Dichroism , DNA/chemistry , Guanidine/chemical synthesis , Guanidine/chemistry , Hydrolysis , Kinetics , Spectrometry, Fluorescence , Spectrophotometry, Ultraviolet
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