scholarly journals Coherence of the Even-Odd Rule with an Effective-Valence Isoelectronicity Rule for Chemical Structural Formulas: Application to Known and Unknown Single-Covalent-Bonded Compounds

2014 ◽  
Vol 04 (03) ◽  
pp. 126-133 ◽  
Author(s):  
Geoffroy Auvert
Keyword(s):  
Structural Formulas ◽  
Effective Valence

scholarly journals In Silico Prediction of Drug–Drug Interactions Mediated by Cytochrome P450 Isoforms

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 538
Author(s):  
Alexander V. Dmitriev ◽  
Anastassia V. Rudik ◽  
Dmitry A. Karasev ◽  
Pavel V. Pogodin ◽  
Alexey A. Lagunin ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Drug Interactions ◽  
Cytochromes P450 ◽  
Investigational Drug ◽  
Web Resource ◽  
Average Accuracy ◽  
Structural Formulas ◽  
Cytochrome P450 Isoforms ◽  
Leave One Out ◽  
Important Drug

Drug–drug interactions (DDIs) can cause drug toxicities, reduced pharmacological effects, and adverse drug reactions. Studies aiming to determine the possible DDIs for an investigational drug are part of the drug discovery and development process and include an assessment of the DDIs potential mediated by inhibition or induction of the most important drug-metabolizing cytochrome P450 isoforms. Our study was dedicated to creating a computer model for prediction of the DDIs mediated by the seven most important P450 cytochromes: CYP1A2, CYP2B6, CYP2C19, CYP2C8, CYP2C9, CYP2D6, and CYP3A4. For the creation of structure–activity relationship (SAR) models that predict metabolism-mediated DDIs for pairs of molecules, we applied the Prediction of Activity Spectra for Substances (PASS) software and Pairs of Substances Multilevel Neighborhoods of Atoms (PoSMNA) descriptors calculated based on structural formulas. About 2500 records on DDIs mediated by these cytochromes were used as a training set. Prediction can be carried out both for known drugs and for new, not-yet-synthesized substances. The average accuracy of the prediction of DDIs mediated by various isoforms of cytochrome P450 estimated by leave-one-out cross-validation (LOO CV) procedures was about 0.92. The SAR models created are publicly available as a web resource and provide predictions of DDIs mediated by the most important cytochromes P450.

Chemical Bonds Properties and Spontaneous Polarization of Orthogonal SrBi2Ta2O9 Crystals

2016 ◽  
Vol 848 ◽  
pp. 688-695
Author(s):  
Xiao Hong Xiao ◽  
Shi Chun Li
Keyword(s):  
Spontaneous Polarization ◽  
Cluster Structure ◽  
Chemical Bonds ◽  
Local Cluster ◽  
Valence Electron Density ◽  
Effective Valence ◽  
Individual Bond ◽  
Atomic Coordination ◽  
Experimental Values ◽  
The Individual

The bonds structure, atomic coordination situation and local cluster structure in SrBi2Ta2O9 were analyzed by means of the Atomic Environment Calculation (AEC), and then the SrBi2Ta2O9 crystal was decomposed into 20 pseudo-binary crystals with the crystal decomposition method. The chemical bonds properties, such as effective valence electron density and iconicity of the individual bond were calculated by the dielectric chemical bonds theory. And the correlation between chemical bonds properties and spontaneous polarization of the bismuth layered ferroelectrics was established. Finally, the spontaneous polarization in ferroelectric SrBi2Ta2O9 and other relevant ferroelectrics were calculated, which are in good agreement with the experimental values and other theoretical calculated values.

ADSORPTION LIQUID CHROMATOGRAPHY OF ETHANOL ELUATE OF ETHANOL EXTRACT OF GREEN WALNUTS+LEAVES (LUGLANS REGIA L., NUT FAMILY - LUGLANDACEAC) (Message VI)

2021 ◽  
Vol 7 (2) ◽  
pp. 17-22
Author(s):  
V. Platonov ◽  
Aleksandr Hadarcev ◽  
G. Suhih ◽  
M. Volochaeva ◽  
I. Dunaeva
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Chemical Composition ◽  
Carboxylic Acids ◽  
Phthalic Acid ◽  
Ethanol Extract ◽  
X Ray ◽  
Chromatography Mass Spectrometry ◽  
Column Adsorption ◽  
Structural Formulas

The aim of the study was to perform column adsorption liquid chromatography in order to obtain ethanol eluate, after preliminary sequential elution of ethanol extract with solvents in the order of their polarity: n–hexane, toluene, chloroform, acetone; to study in detail the chemical composition of this eluate by chromatography-mass spectrometry and X-ray fluorescence spectroscopy, with the intensification of compounds determining the composition of eluate, obtaining their masses -spectra, structural formulas, determination of the nature of trace elements. Materials and methods of research. A detailed study of the chemical composition of acetone eluate of ethanol extract of walnuts+ leaves was carried out using column adsorption liquid chromatography, chromato-mass spectrometry and X-ray fluorescence analysis. The results and their discussion. The features of the chemical composition of ethanol eluate of the product of column adsorption liquid chromatography of ethanol extract were studied, the qualitative composition and quantitative content of compounds identified in the first one were established by chromatography-mass spectrometry. Mass spectra and structural formulas were obtained for 31 individual eluate compounds. Ethanol eluate is characterized by the following indicators of structural and group composition (mass. % of eluate): esters of phthalic acid - 52.14, silicon and sulfur-containing compounds, respectively - 20.19 and 6.43, hydrocarbons - 15.38, glycosides - 2.21, alcohols - 1.92, carboxylic acids - 1.07, sterols - 0.89. It is assumed that the pharmacological effect of ethanol eluate is mainly determined by a set of free carboxylic acids, as well as phthalic acid, formed as a result of biochemical and hydrological transesterification of its esters containing compounds, alcohols, glycosides and sterols. Organosilicon compounds during hydrolysis give silica in the size of nanoparticles, which play the role of carriers of the above compounds to various organs of a living organism, as well as drainage of blood vessels from the products of cell metabolism, for example, cholesterol, various fats, etc. A comparative characteristic of the chemical composition of all ethanol extract eluates was carried out, the effectiveness of column adsorption liquid chromatography was shown.

scholarly journals Structural and Electrical Studies for Birnessite-Type Materials Synthesized by Solid-State Reactions

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1156 ◽  
Author(s):  
Nayda P. Arias ◽  
María E. Becerra ◽  
Oscar Giraldo
Keyword(s):  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Nitrogen Adsorption ◽  
Synthesis Temperature ◽  
Thermal Reduction ◽  
Solid State Reactions ◽  
Low Frequencies ◽  
Structural Formulas ◽  
Interlayer Region ◽  
Adsorption Desorption

The focus of this paper is centered on the thermal reduction of KMnO4 at controlled temperatures of 400 and 800 °C. The materials under study were characterized by atomic absorption spectroscopy, thermogravimetric analysis, average oxidation state of manganese, nitrogen adsorption–desorption, and impedance spectroscopy. The structural formulas, found as a result of these analyses, were K 0.29 + ( M n 0.84 4 + M n 0.16 3 + ) O 2.07 · 0.61 H 2 O and K 0.48 + ( M n 0.64 4 + M n 0.36 3 + ) O 2.06 · 0.50 H 2 O . The N2 adsorption–desorption isotherms show the microporous and mesoporous nature of the structure. Structural analysis showed that synthesis temperature affects the crystal size and symmetry, varying their electrical properties. Impedance spectroscopy (IS) was used to measure the electrical properties of these materials. The measurements attained, as a result of IS, show that these materials have both electronic and ionic conductivity. The conductivity values obtained at 10 Hz were 4.1250 × 10−6 and 1.6870 × 10−4 Ω−1cm−1 for Mn4 at 298 and 423 K respectively. For Mn8, the conductivity values at this frequency were 3.7074 × 10−7 (298) and 3.9866 × 10−5 Ω−1cm−1 (423 K). The electrical behavior was associated with electron hopping at high frequencies, and protonic conduction and ionic movement of the K+ species, in the interlayer region at low frequencies.

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