Scanning Electronic Microscopy Study of New Theophyline Compounds with Metallic Ions

2008 ◽  
Vol 59 (5) ◽  
Author(s):  
Eleonora Marian ◽  
Tunde Jurca ◽  
Florin Banica ◽  
Bogdan Tita ◽  
Dumitru Tita
Keyword(s):  
Chemical Properties ◽  
Microscopy Study ◽  
Complex Compounds ◽  
Metallic Ions ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Transitional Metals ◽  
Energy Capture ◽  
Elementary Analysis ◽  
Physico Chemical

Although they represent mere 3% of the human body, the metallic ions (especially those of the transitional metals from 3d series), under the form of some natural chelate compounds, they intervene in all the fundamental biologic processes, solar energy capture, photosynthesis, oxygen and nitrogen fixation and transportation, coordination of all metabolic reactions and controlled discharge of the energy in the biologic systems. Furthermore, the formation of complex compounds has implications in the explanation of some biological processes or pathological states and may constitute models for the study of the drugs� pharmaco-dynamic effects. In this study is presented the manner in which are prepared three theophyline compounds with transitional metal ions, their physico-chemical properties, the results of the elementary analysis, as well as the examination by scanning electronic microscopy of these compounds particles form.

scholarly journals Studies on Cyanex-272 Complexes of Mg (II), Ca (II) and Fe (III)

1970 ◽  
Vol 42 (4) ◽  
pp. 475-482 ◽  
Author(s):  
M Badrul Islam ◽  
M Zahurul Haque ◽  
N Shamsul Islam
Keyword(s):  
Key Words ◽  
Magnetic Measurements ◽  
Phosphinic Acid ◽  
Chemical Properties ◽  
Decomposition Temperature ◽  
Complex Compounds ◽  
The Other ◽  
Spectral Studies ◽  
Cyanex 272 ◽  
Physico Chemical

Certain complex compounds were synthesized by the interaction of Mg(II), Ca(II) and Fe(III) halides with the solvent extracting reagent, Cyanex-272 i.e. bis (2,4,4- trimethylpentyl) phosphinic acid as ligand. All the prepared complexes have been characterized on the basis of their molar masses, conductivity, magnetic measurements and infrared and electronic spectral studies. The other physico-chemical properties e.g. colour, decomposition temperature have also been ascertained. Key words: Chanex-272 Bangladesh J. Sci. Ind. Res. 42(4), 475-482, 2007

Characterization of Shivirtui Zeolite Modified with Aluminum Oxyhydroxide Nanofibers

2019 ◽  
Vol 942 ◽  
pp. 40-49
Author(s):  
Yulia Murashkina ◽  
Olga B. Nazarenko
Keyword(s):  
Chemical Properties ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
X Ray ◽  
Physical And Chemical ◽  
And Chemical Properties ◽  
Aluminum Oxyhydroxide

Natural zeolite of Shivirtui deposit (Russia) was modified with nanofibers of aluminum oxyhydroxide AlOOH. Aluminum oxyhydroxide nanofibers were produced at the heating and oxidation of aluminum powder with water. The properties of modified zeolite were investigated by means of X-ray diffraction, transmission electronic microscopy, scanning electronic microscopy, low-temperature nitrogen adsorption, thermal analysis, and Fourier transform infrared spectroscopy. It was found that water content in the modified sample of zeolite was about 15 %. Based on the study of the physical and chemical properties, shivirtui zeolite modified with nanofibers of aluminum oxyhydroxide can be proposed for use as a flame-retardant additive to polymers.

scholarly journals Foraminal Deformation after Foraminal Enlargement with Rotary and Reciprocating Kinematics: A Scanning Electronic Microscopy Study

2018 ◽  
Vol 44 (1) ◽  
pp. 145-148 ◽  
Author(s):  
Adriana Martins Silva Santos ◽  
Francisca Meire Soares de Freitas Portela ◽  
Marcelo Santos Coelho ◽  
Carlos Eduardo Fontana ◽  
Alexandre Sigrist De Martin
Keyword(s):  
Microscopy Study ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy

scholarly journals Profiling and analysis of chemical compounds using pointwise mutual information

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
I. Čmelo ◽  
M. Voršilák ◽  
D. Svozil
Keyword(s):  
Random Forest ◽  
Mutual Information ◽  
Structural Feature ◽  
Chemical Properties ◽  
Structural Features ◽  
Complex Compounds ◽  
Physico Chemical ◽  
Synthetic Accessibility ◽  
Measure Of Association ◽  
Pointwise Mutual Information

AbstractPointwise mutual information (PMI) is a measure of association used in information theory. In this paper, PMI is used to characterize several publicly available databases (DrugBank, ChEMBL, PubChem and ZINC) in terms of association strength between compound structural features resulting in database PMI interrelation profiles. As structural features, substructure fragments obtained by coding individual compounds as MACCS, PubChemKey and ECFP fingerprints are used. The analysis of publicly available databases reveals, in accord with other studies, unusual properties of DrugBank compounds which further confirms the validity of PMI profiling approach. Z-standardized relative feature tightness (ZRFT), a PMI-derived measure that quantifies how well the given compound’s feature combinations fit these in a particular compound set, is applied for the analysis of compound synthetic accessibility (SA), as well as for the classification of compounds as easy (ES) and hard (HS) to synthesize. ZRFT value distributions are compared with these of SYBA and SAScore. The analysis of ZRFT values of structurally complex compounds in the SAVI database reveals oligopeptide structures that are mispredicted by SAScore as HS, while correctly predicted by ZRFT and SYBA as ES. Compared to SAScore, SYBA and random forest, ZRFT predictions are less accurate, though by a narrow margin (AccZRFT = 94.5%, AccSYBA = 98.8%, AccSAScore = 99.0%, AccRF = 97.3%). However, ZRFT ability to distinguish between ES and HS compounds is surprisingly high considering that while SYBA, SAScore and random forest are dedicated SA models, ZRFT is a generic measurement that merely quantifies the strength of interrelations between structural feature pairs. The results presented in the current work indicate that structural feature co-occurrence, quantified by PMI or ZRFT, contains a significant amount of information relevant to physico-chemical properties of organic compounds.

Preparation and scanning electronic microscopy study of chitosan/polyvinyl (alcohol)-encapsulated crude urease extract

1997 ◽  
Vol 14 (5) ◽  
pp. 639-646 ◽  
Author(s):  
M. J. B. Miguezb ◽  
C. Rodrigues ◽  
M. De N. M. Sanchez ◽  
M. C. M. Lafunjeira
Keyword(s):  
Polyvinyl Alcohol ◽  
Microscopy Study ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy

scholarly journals Profiling and analysis of chemical compounds using pointwise mutual information

2020 ◽  
Author(s):  
Daniel Svozil ◽  
Ivan Čmelo ◽  
Milan Voršilák
Keyword(s):  
Random Forest ◽  
Mutual Information ◽  
Structural Feature ◽  
Chemical Properties ◽  
Structural Features ◽  
Complex Compounds ◽  
Physico Chemical ◽  
Synthetic Accessibility ◽  
Measure Of Association ◽  
Pointwise Mutual Information

Abstract Pointwise mutual information (PMI) is a measure of association used in information theory. In this paper, PMI is used to characterize several publicly available databases (DrugBank, ChEMBL, PubChem and ZINC) in terms of association strength between compound structural features resulting in database PMI interrelation profiles. As structural features, substructure fragments obtained by coding individual compounds as MACCS, PubChemKey and ECFP fingerprints are used. The analysis of publicly available databases reveals, in accord with other studies, unusual properties of DrugBank compounds which further confirms the validity of PMI profiling approach. Z-standardized relative feature tightness (ZRFT), a PMI-derived measure that quantifies how well the given compound’s feature combinations fit these in a particular compound set, is applied for the analysis of compound synthetic accessibility (SA), as well as for the classification of compounds as easy (ES) and hard (HS) to synthesize. ZRFT value distributions are compared with these of SYBA and SAScore. The analysis of ZRFT values of structurally complex compounds in the SAVI database reveals oligopeptide structures that are mispredicted by SAScore as HS, while correctly predicted by ZRFT and SYBA as ES. Compared to SAScore, SYBA and random forest, ZRFT predictions are less accurate, though by a narrow margin (AccZRFT = 94.5%, AccSYBA = 98.8%, AccSAScore = 99.0%, AccRF = 97.3%). However, ZRFT ability to distinguish between ES and HS compounds is surprisingly high considering that while SYBA, SAScore and random forest are dedicated SA models, ZRFT is a generic measurement that merely quantifies the strength of interrelations between structural feature pairs. The results presented in the current work indicate that structural feature co-occurrence, quantified by PMI or ZRFT, contains a significant amount of information relevant to physico-chemical properties of organic compounds.

Sintering of Y2O3-Stabilized ZrO2 Powders Obtained by Different Chemical Methods

2008 ◽  
Vol 591-593 ◽  
pp. 649-653 ◽  
Author(s):  
R.E.P. Salem ◽  
Adilson Luiz Chinelatto ◽  
Adriana Scoton Antonio Chinelatto
Keyword(s):  
Pechini Method ◽  
High Reactivity ◽  
Metallic Ions ◽  
X Ray Diffraction ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Chemical Methods ◽  
Chemical Homogeneity ◽  
X Ray ◽  
Average Size

The chemical methods allow obtaining powders with high reactivity and chemical homogeneity. This work studied the sintering of Y2O3-stabilized ZrO2 powders produced by polymerization routes. In the three methods used were obtained powders via formation of gels, which were characterized by spectroscopy in the infrared. After the gel calcinations, the powders obtained were characterized by X-ray diffraction and scanning electronic microscopy (SEM). Among the different chemical methods, there were differences in the coordination of the metallic ions, which caused differences in the thermal behavior, reactivity, size and form of the particles of the powders. The powders were pressed and sintered at 1400 and 1600°C for 2 hours. The bodies sintered were characterized by SEM, apparent density and dilatometry. The average size of the particles varied with the method, and the smallest particles were obtained by Pechini method. PCS method showed a strong reactivity of the powder and it was already partially sintered even in the step of elimination of organic substances. Similarly, the sintered compacts presented different properties with each other, and the compacts obtained by PEG/FA method had the best microstructure.

scholarly journals Titanium Oxide Modification With Oxides of Mixed Cobalt Valence for Photocatalysis

2019 ◽  
Vol 54 (3) ◽  
Author(s):  
Roberto Alanís-Oaxaca ◽  
Jaime Jiménez-Becerril
Keyword(s):  
Sol Gel ◽  
Chemical Properties ◽  
X Ray Diffraction ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
X Ray ◽  
Metallic Oxides ◽  
Degussa P25 ◽  
Physical And Chemical ◽  
And Chemical Properties

In the present work, heterogenous photocatalysis, a technique often used for organic compound degradation toxic in water, was used. The photocatalyst most often used in this technique is TiO2, which, due to its physical and chemical properties, can degrade a great number of organic compounds. In addition, in recent years it has been verified that the doping of semiconductors with metals or metallic oxides increases the photocatalytic activity of these semiconductors, which is why it was proposed for doping by the impregnating method using commercial TiO2 synthesized by the Degussa company (TiO2 Degussa P25) with an oxide of mixed cobalt valence (Co3O4) synthesized using the sol-gel method. The synthesized photocatalyst TiO2/Co3O4 was characterized by the techniques of X-ray diffraction (RXD), scanning electronic microscopy (SEM), Raman spectroscopy (RS), and, finally, photocatalytic tests by means of the degradation of methylene blue.  

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