Selection of Descriptors According to Discrimination and Redundancy. Application to Chemical Structure Searching

1976 ◽  
Vol 16 (2) ◽  
pp. 88-93 ◽  
Author(s):  
Louis Hodes
Keyword(s):  
Chemical Structure ◽  
Selection Of Descriptors ◽  
Selection Of

scholarly journals Selection of Descriptors in a Morphological Characteristics Considered In Cassava Accessions By Means Of Multivariate Techniques

2014 ◽  
Vol 7 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Sandra Domingos João Afonso ◽  
◽  
Carlos Alberto da Silva Ledo ◽  
Ricardo Franco Cunha Moreira ◽  
Sebastião de Oliveira e Silva ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Multivariate Techniques ◽  
Selection Of Descriptors ◽  
Selection Of

Amidinoanthracyclines – a new group of potential anti-hepatitis C virus compounds

2009 ◽  
Vol 390 (4) ◽  
Author(s):  
Mariusz Krawczyk ◽  
Malgorzata Wasowska-Lukawska ◽  
Irena Oszczapowicz ◽  
Anna M. Boguszewska-Chachulska
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Chemical Structure ◽  
Hydroxyl Group ◽  
Current Therapy ◽  
Helicase Activity ◽  
Double Stranded Dna ◽  
Helicase Assay ◽  
Dna Substrate ◽  
Selection Of

Abstract Hepatitis C virus (HCV) infections represent one of the major and still unresolved health problems because current therapy is effective in only 50–80% of cases, depending on viral genotype. A large group of amidinoanthracyclines, with decreased acute toxicity and cardiotoxicity compared to the parent antibiotics, was tested in a high-throughput fluorometric HCV helicase assay. Here, we report the selection of more than 50 potent inhibitors of helicase activity that inhibit the enzyme with IC50 values in the range of 0.03–10 μm; four of these compounds are the most potent inhibitors of helicase activity described in the literature. The activity of these inhibitors is highly dependent on their chemical structure, mainly on the substituent at the amidino carbon atom and on the orientation of the hydroxyl group at the 4′ position of the daunosamine moiety. The most effective compounds act not solely via intercalation into the double-stranded DNA substrate, but also compete with the enzyme for access to the substrate, impeding formation of the active helicase complex. Selected amidinoanthracyclines were tested in the subgenomic HCV replicon system. These experiments confirmed the antiviral activity of two selected inhibitors (EC50 values below 0.2 μm with selectivity indices of 19 and 33) and proved that they may be considered as potential anti-HCV drugs.

scholarly journals A GMDH-type neural network with multi-filter feature selection for the prediction of transition temperatures of bent-core liquid crystals

RSC Advances ◽  
2016 ◽  
Vol 6 (102) ◽  
pp. 99676-99684 ◽  
Author(s):  
Davor Antanasijević ◽  
Jelena Antanasijević ◽  
Viktor Pocajt ◽  
Gordana Ušćumlić
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Feature Selection ◽  
Transition Temperatures ◽  
Chi Square ◽  
Qspr Study ◽  
Selection For ◽  
Filter Approach ◽  
Selection Of Descriptors ◽  
Selection Of

The QSPR study on transition temperatures of five-ring bent-core LCs was performed using GMDH-type neural networks. A novel multi-filter approach, which combines chi square ranking, v-WSH and GMDH algorithm was used for the selection of descriptors.

scholarly journals The DFT calculations of pKa values of the cationic acids of aniline and pyridine derivatives in common solvents

2014 ◽  
Vol 7 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Peter Poliak
Keyword(s):  
Experimental Data ◽  
Chemical Structure ◽  
Reaction Scheme ◽  
Isodesmic Reaction ◽  
Pka Values ◽  
Good Accordance ◽  
Derivatives Of ◽  
Pyridinium Ion ◽  
Theoretical Results ◽  
Selection Of

Abstract The theoretical pKa values of the derivatives of anilinium and pyridinium ions in 7 solvents are presented. For this purpose, the usage of isodesmic reaction scheme using the DFT/B3LYP approach with IEFPCM solvation was evaluated. We have shown that the suitable selection of reference species has the primary influence on the resulting data. For the studied anilinium ion derivatives the nonsubstituted anilinium ion seems to be a satisfactory reference system. The calculated values are in good accordance with the available experimental data with the RMS error of 1.00 and 0.99 pKa units in water and THF, respectively. The highest error in predicted pKa value is less than 2.0 pKa units in all cases. The chemical accuracy of the applied treatment is limited in the case of nitroaniline ions and the maximal therotetical uncertainty for derivatives of the pyridinium ion is within 2.1 pKa units. Our theoretical results enable us to predict the values of pKa for the solvents, where the experimental data are not completely available. Also the influence of the chemical structure on the accuracy of the applied method was discussed.

scholarly journals The Old and New Visions of Biased Agonism Through the Prism of Adenosine Receptor Signaling and Receptor/Receptor and Receptor/Protein Interactions

2021 ◽  
Vol 11 ◽  
Author(s):  
Rafael Franco ◽  
Rafael Rivas‐Santisteban ◽  
Irene Reyes-Resina ◽  
Gemma Navarro
Keyword(s):  
Protein Interactions ◽  
Chemical Structure ◽  
Research Field ◽  
Receptor Protein ◽  
Functional Selectivity ◽  
Biased Agonism ◽  
Receptor Interactions ◽  
Biased Signaling ◽  
G Protein Coupled ◽  
Selection Of

Biased signaling is a concept that has arisen in the G protein-coupled receptor (GCPR) research field, and holds promise for the development of new drug development strategies. It consists of different signaling outputs depending on the agonist’s chemical structure. Here we review the most accepted mechanisms for explaining biased agonism, namely the induced fit hypothesis and the key/lock hypothesis, but we also consider how bias can be produced by a given agonist. In fact, different signaling outputs may originate at a given receptor when activated by, for instance, the endogenous agonist. We take advantage of results obtained with adenosine receptors to explain how such mechanism of functional selectivity depends on the context, being receptor-receptor interactions (heteromerization) one of the most relevant and most studied mechanisms for mammalian homeostasis. Considering all the possible mechanisms underlying functional selectivity is essential to optimize the selection of biased agonists in the design of drugs targeting GPCRs.

Research of Characteristics Extraction Based on Dynamic Pressure Signal

2013 ◽  
Vol 329 ◽  
pp. 354-358
Author(s):  
Wei Liu ◽  
Hong Zhao Liu
Keyword(s):  
Pattern Recognition ◽  
Feature Selection ◽  
Dynamic Pressure ◽  
Statistical Characteristics ◽  
Pressure Signal ◽  
Selection Of Descriptors ◽  
Oscillation Characteristic ◽  
Selection Of

The accuracy of pattern recognition was determined by the feature selection, and two methods of the characteristic description were discussed. The results show that the statistical characteristics could be used as a dynamic pressure signal descriptor, and the oscillation characteristic of curve is not suitable for describing dynamic pressure signal by itself. The selection of descriptors of dynamic pressure signal is the precondition to identify the leak signal and the non-leak signal effectively.

scholarly journals The Influence of Plasma-Assisted Production and Milling Processes of DLC Flakes on Their Size, Composition and Chemical Structure

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1209 ◽  
Author(s):  
Tomasz Kaźmierczak ◽  
Piotr Niedzielski ◽  
Witold Kaczorowski
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Structure ◽  
Vapour Deposition ◽  
Electrode Materials ◽  
Chemical Vapour ◽  
Size Composition ◽  
Dual Frequency ◽  
Frequency Method ◽  
Frequent Problem ◽  
Selection Of

Diamond-like carbon (DLC) flakes were produced using a dual-frequency method: microwave/radiofrequency plasma-assisted chemical vapour deposition (MW/RF PACVD) with the use of methane or its mixture with gases such as hydrogen, argon, oxygen or nitrogen. Their modification was performed using a planetary ball mill with and without a fluid: deionised water or methanol. Changes occurring in the morphology of flake surfaces were presented in pictures taken using a scanning electron microscope (SEM). Their composition and chemical structure were analysed using Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The presented research results show that it is possible to control the size of flakes and their chemical structure. An increase in the C-C sp3 bond content in produced carbon-based materials is only possible by modifying DLC flakes during their production process by introducing oxygen or argon into the working chamber together with the carbon-carrying gas. In the processes of mechanical DLC flake modification, it is necessary to add fluid to limit the occurrence of graphitisation processes. The research conducted shows that methanol is best used for this purpose as its use results in a decrease in the percentage of C-C sp3 bonds as compared to the materials, before milling, of only 1.7%. A frequent problem both in the production of DLC flakes and during their mechanical modification is the introduction of additional elements into their structure. Admixing electrode materials from the plasma-chemical device (iron) or grinding beads (zirconium) to DLC flakes was observed in our studies. These processes can be limited by the appropriate selection of production conditions or by mechanical modifications.

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