Influence of Copolycondensation Conditions on the Synthesis and Properties of Aromatic Copolyesulphonketones

2021 ◽  
Vol 899 ◽  
pp. 532-539
Author(s):  
Aues A. Beev ◽  
Azamat A. Khashirov ◽  
Dzhul’etta A. Beeva ◽  
M.U. Shokumova ◽  
V.V. Khasanov
Keyword(s):  
Chemical Structure ◽  
Performance Characteristics ◽  
Chemical Structures ◽  
Reduced Viscosity

The paper investigates the dependence of the reduced viscosity and some properties of aromatic copolyethersulfone ketones on the chemical structure of diphenols and activated dihaloid compounds on the conditions of copolycondensation processes. It is shown that the course of copolycondensation processes and important performance characteristics of products are significantly influenced by the chemical structures of the starting monomers and the order of their introduction into the reaction.

Chemical structure of diamond-like carbon thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 710-711
Author(s):  
N.-H. Cho ◽  
K.M. Krishnan ◽  
D.B. Bogy
Keyword(s):  
Electrical Resistivity ◽  
Chemical Structure ◽  
Diamond Like Carbon ◽  
Chemical Structures ◽  
Sputtering Power ◽  
Data Aquisition ◽  
Equilibrium Phases ◽  
Electron Energy Loss ◽  
Power Densities ◽  
Preparation Techniques

Diamond-like carbon (DLC) films have attracted much attention due to their useful properties and applications. These properties are quite variable depending on film preparation techniques and conditions, DLC is a metastable state formed from highly non-equilibrium phases during the condensation of ionized particles. The nature of the films is therefore strongly dependent on their particular chemical structures. In this study, electron energy loss spectroscopy (EELS) was used to investigate how the chemical bonding configurations of DLC films vary as a function of sputtering power densities. The electrical resistivity of the films was determined, and related to their chemical structure.DLC films with a thickness of about 300Å were prepared at 0.1, 1.1, 2.1, and 10.0 watts/cm2, respectively, on NaCl substrates by d.c. magnetron sputtering. EEL spectra were obtained from diamond, graphite, and the films using a JEOL 200 CX electron microscope operating at 200 kV. A Gatan parallel EEL spectrometer and a Kevex data aquisition system were used to analyze the energy distribution of transmitted electrons. The electrical resistivity of the films was measured by the four point probe method.

scholarly journals A Further Comprehensive Review on the Phytoconstituents from the Genus Erythrina

2020 ◽  
Vol 23 (1) ◽  
pp. 65-77 ◽  
Author(s):  
Mohammad Musarraf Hussain
Keyword(s):  
Chemical Structure ◽  
Biological Activities ◽  
Chemical Constituents ◽  
Pharmaceutical Journal ◽  
Significant Source ◽  
Comprehensive Review ◽  
Chemical Structures ◽  
Previous Review

Erythrina is a significant source of phytoconstituents. The aim of this review is to solicitude of classification, synthesis, and phytochemicals with biological activities of Erythrina. In our previous review on this genus (Hussain et. al., 2016a) fifteen species (Erythrina addisoniae, E. caribeae, E. indica, E. lattisima, E. melanacantha, E. mildbraedii, E. poeppigiama, E. stricta, E. subumbrans, E. veriagata, E. vespertilio, E. velutina, E. zeberi, E. zeyheri and E. americana) have been studied and 155 molecules with chemical structures were reported. A further comprehensive review was done upon continuation on the same genus and thirteen species (E. abyssinica, E. arborescens, E. berteroana, E. burttii, E. caffra, E. coralloids, E. crista-galli, E. fusca, E. herbaceae, E. lysistemon, E. mulungu, E. speciosa and E. tahitensis) of Erythrina have been studied and 127 compounds are reported as phytoconstituents with their chemical structure in this review. Erythrina crista-galli and E. lysistemon consist of highest number of chemical constituents. Bangladesh Pharmaceutical Journal 23(1): 65-77, 2020

scholarly journals A Review of Bacteriochlorophyllides: Chemical Structures and Applications

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1293
Author(s):  
Chih-Hui Yang ◽  
Keng-Shiang Huang ◽  
Yi-Ting Wang ◽  
Jei-Fu Shaw
Keyword(s):  
Solar Cell ◽  
Energy Harvesting ◽  
Chemical Structure ◽  
The Other ◽  
Dye Sensitized Solar Cell ◽  
Synthetic Route ◽  
Chemical Structures ◽  
Dye Sensitized ◽  
Heme Synthesis ◽  
Potential Applications

Generally, bacteriochlorophyllides were responsible for the photosynthesis in bacteria. Seven types of bacteriochlorophyllides have been disclosed. Bacteriochlorophyllides a/b/g could be synthesized from divinyl chlorophyllide a. The other bacteriochlorophyllides c/d/e/f could be synthesized from chlorophyllide a. The chemical structure and synthetic route of bacteriochlorophyllides were summarized in this review. Furthermore, the potential applications of bacteriochlorophyllides in photosensitizers, immunosensors, influence on bacteriochlorophyll aggregation, dye-sensitized solar cell, heme synthesis and for light energy harvesting simulation were discussed.

scholarly journals Influence of the chemical structure of cation surfactants on the wetting process of rock-forming minerals

2019 ◽  
Vol 55 (2) ◽  
pp. 142-148
Author(s):  
O. N. Opanasenko ◽  
N. P. Krutko ◽  
O. L. Zhigalova ◽  
O. V. Luksha
Keyword(s):  
Cationic Surfactants ◽  
Chemical Structure ◽  
Polyhydric Alcohol ◽  
Amino Groups ◽  
Interfacial Interactions ◽  
Alkyl Chains ◽  
Chemical Structures ◽  
Adsorption Interaction ◽  
Wetting Process ◽  
Steric Hindrances

Interfacial interactions of cationic surfactants of various chemical structures at the solution / finely dispersed mineral material (quartz and dolomite) interface were studied. It is established that the modification of the surfaces of quartz and dolomite with cationic surfactants leads to a change in the structure and radius of the capillaries due to the formation of adsorption-solvate shells. The hydrophobic ability of cationic surfactants is determined by the structure of the hydrophilic part of their molecules – the balance of amino groups in the alkyl chains and the absence of steric hindrances during adsorption interaction with the surface of mineral materials. The mixture of surfactants containing six amino groups and a polyhydric alcohol glycerin has an effective hydrophobic ability from both aqueous and highly mineralized solutions.

scholarly journals Chemical Structure of Mangrove Species Rhizophora stylosa as Natural Dyes

METANA ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 33-38
Author(s):  
Paryanto Paryanto ◽  
Sunu Herwi Pranolo ◽  
Ari Diana Susanti ◽  
Kristina Ratna Dewi ◽  
Meydiana Rossari
Keyword(s):  
Chemical Structure ◽  
Liquid Extraction ◽  
Natural Dyes ◽  
Synthetic Dyes ◽  
Mangrove Species ◽  
Rhizophora Stylosa ◽  
Solid Mixture ◽  
Chemical Structures ◽  
Ft Ir ◽  
Solid Liquid

Textile dyes are divided into two types, natural dyes and synthetic dyes. Natural dyes commonly made from extraction. Extraction is a process in which one or more components are separated selectively from a liquid or solid mixture, the feed, by means of a liquid immiscible solvent. Extraction can be classified into two group, liquid extraction and solid-liquid extraction. Solvents that are usually used in the extraction of natural dyes are aquades and ethanol. The purpose of this research was to determine the chemical structure, especially tannin in natural dyes from mangrove species Rhizophora stylosa through several samples testing natural dyes. Rhizophora stylosa that have been extracted and evaporated will conducted several tests to obtain chemical structures in natural dyes and yield of tannin in natural dyes. Tests carried out include testing FT-IR, and HPLC. Based on FT-IR analysis, the extraction of Rhizophora stylosa containing tannin indicated by the presence of hydroxyl (O-H) in the area of 3385.36 cm-1, aromatic (C-H) in the area of 1365.53 cm-1, carbonyl (C=O) in the area 1646.36 cm-1, esters (C-O) in the area 1217.30 cm-1. While tannin content obtained from the analysis of HPLC were 6.087 ppm. 

Influence of the Chemical Structure of Functional Monomers on Their Adhesive Performance

2008 ◽  
Vol 87 (8) ◽  
pp. 757-761 ◽  
Author(s):  
K.L. Van Landuyt ◽  
Y. Yoshida ◽  
I. Hirata ◽  
J. Snauwaert ◽  
J. De Munck ◽  
...  
Keyword(s):  
Bond Strength ◽  
Dissolution Rate ◽  
Chemical Bonding ◽  
Chemical Structure ◽  
Calcium Salt ◽  
Atomic Absorption Spectrophotometry ◽  
Functional Monomer ◽  
Functional Monomers ◽  
Chemical Structures ◽  
Adhesive Performance

Functional monomers in adhesive systems can improve bonding by enhancing wetting and demineralization, and by chemical bonding to calcium. This study tested the hypothesis that small changes in the chemical structure of functional monomers may improve their bonding effectiveness. Three experimental phosphonate monomers (HAEPA, EAEPA, and MAEPA), with slightly different chemical structures, and 10-MDP (control) were evaluated. Adhesive performance was determined in terms of microtensile bond strength of 4 cements that differed only for the functional monomer. Based on the Adhesion-Decalcification concept, the chemical bonding potential was assessed by atomic absorption spectrophotometry of the dissolution rate of the calcium salt of the functional monomers. High bond strength of the adhesive cement corresponded to low dissolution rate of the calcium salt of the respective functional monomer. The latter is according to the Adhesion-Decalcification concept, suggestive of a high chemical bonding capacity. We conclude that the adhesive performance of an adhesive material depends on the chemical structure of the functional monomer.

The Chemical Structure Association Trust

2016 ◽  
Vol 38 (2) ◽  
Author(s):  
Bonnie Lawlor
Keyword(s):  
Chemical Structure ◽  
Scientific Discovery ◽  
Research Work ◽  
50Th Anniversary ◽  
The United States ◽  
Chemical Information ◽  
Structure Information ◽  
Chemical Structures ◽  
Grant Program ◽  
Structure Association

AbstractThe Chemical Structure Association Trust (CSA Trust) is an internationally-recognized, registered charity that promotes and supports the advancement of scientific discovery through the application of computer technologies in the management and analysis of chemical structure information. In support of its Charter, the Trust provides grants specifically to nurture young scientists, ages thirty-five or younger, who have demonstrated excellence in research related to the storage, retrieval, and analysis of chemical structures, reactions, and compounds. Since its inception in 1988, almost one hundred students and researchers worldwide have benefited from travel bursaries and the CSA Trust Grant Program to further their education and research work, but the organization has a rich history that predates the formalization of its charity status. Its roots were planted half a century ago in 1965, when the Chemical Notation Association (CNA) was formed in the United States. It has been an interesting journey from the CNA to the CSA Trust and I have been blessed to have been a part of it almost from the beginning, along with other members of the American Chemical Society’s Division of Chemical Information. In honor of the organization’s 50th Anniversary, I’d like to give a brief overview of its past and its present activities.

scholarly journals Chemical Structure, Biological Roles, Biosynthesis and Regulation of the Yellow Xanthomonadin Pigments in the Phytopathogenic Genus Xanthomonas

2020 ◽  
Vol 33 (5) ◽  
pp. 705-714 ◽  
Author(s):  
Ya-Wen He ◽  
Xue-Qiang Cao ◽  
Alan R. Poplawsky
Keyword(s):  
Chemical Structure ◽  
Xanthomonas Campestris ◽  
Bacterial Species ◽  
Regulatory Mechanisms ◽  
Chemical Structures ◽  
Considerable Research ◽  
Membrane Bound ◽  
Yellow Pigments ◽  
Epiphytic Survival ◽  
Xanthomonas Campestris Pv Campestris

Xanthomonadins are membrane-bound yellow pigments that are typically produced by phytopathogenic bacterial Xanthomonas spp., Xylella fastidiosa, and Pseudoxanthomonas spp. They are also produced by a diversity of environmental bacterial species. Considerable research has revealed that they are a unique group of halogenated, aryl-polyene, water-insoluble pigments. Xanthomonadins have been shown to play important roles in epiphytic survival and host-pathogen interactions in the phytopathogen Xanthomonas campestris pv. campestris, which is the causal agent of black rot in crucifers. Here, we review recent advances in the understanding of xanthomonadin chemical structures, physiological roles, biosynthetic pathways, regulatory mechanisms, and crosstalk with other signaling pathways. The aim of the present review is to provide clues for further in-depth research on xanthomonadins from Xanthomonas and other related bacterial species.

Deep-DRM: a computational method for identifying disease-related metabolites based on graph deep learning approaches

2020 ◽  
Author(s):  
Tianyi Zhao ◽  
Yang Hu ◽  
Liang Cheng
Keyword(s):  
Deep Learning ◽  
Chemical Structure ◽  
Computational Method ◽  
Learning Approaches ◽  
Convolutional Network ◽  
Functional Changes ◽  
Chemical Structures ◽  
Association Pattern ◽  
Semantic Associations ◽  
Components Analysis

Abstract Motivation: The functional changes of the genes, RNAs and proteins will eventually be reflected in the metabolic level. Increasing number of researchers have researched mechanism, biomarkers and targeted drugs by metabolites. However, compared with our knowledge about genes, RNAs, and proteins, we still know few about diseases-related metabolites. All the few existed methods for identifying diseases-related metabolites ignore the chemical structure of metabolites, fail to recognize the association pattern between metabolites and diseases, and fail to apply to isolated diseases and metabolites. Results: In this study, we present a graph deep learning based method, named Deep-DRM, for identifying diseases-related metabolites. First, chemical structures of metabolites were used to calculate similarities of metabolites. The similarities of diseases were obtained based on their functional gene network and semantic associations. Therefore, both metabolites and diseases network could be built. Next, Graph Convolutional Network (GCN) was applied to encode the features of metabolites and diseases, respectively. Then, the dimension of these features was reduced by Principal components analysis (PCA) with retainment 99% information. Finally, Deep neural network was built for identifying true metabolite-disease pairs (MDPs) based on these features. The 10-cross validations on three testing setups showed outstanding AUC (0.952) and AUPR (0.939) of Deep-DRM compared with previous methods and similar approaches. Ten of top 15 predicted associations between diseases and metabolites got support by other studies, which suggests that Deep-DRM is an efficient method to identify MDPs. Contact: [email protected]. Availability and implementation: https://github.com/zty2009/GPDNN-for-Identify-ing-Disease-related-Metabolites.

scholarly journals Tracing the cold and warm physico-chemical structure of deeply embedded protostars: IRAS 16293−2422 vs. VLA 1623−2417

2018 ◽  
Vol 617 ◽  
pp. A120 ◽  
Author(s):  
N. M. Murillo ◽  
E. F. van Dishoeck ◽  
M. H. D. van der Wiel ◽  
J. K. Jørgensen ◽  
M. N. Drozdovskaya ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Cavity Wall ◽  
Key Factors ◽  
Chemical Complexity ◽  
Chemical Structures ◽  
Chemical Models ◽  
Physico Chemical ◽  
Envelope Material ◽  
Low Mass ◽  
Dust Distribution

Context. Much attention has been placed on the dust distribution in protostellar envelopes, but there are still many unanswered questions regarding the physico-chemical structure of the gas. Aims. Our aim is to start identifying the factors that determine the chemical structure of protostellar regions, by studying and comparing low-mass embedded systems in key molecular tracers. Methods. The cold and warm chemical structures of two embedded Class 0 systems, IRAS 16293−2422 and VLA 1623−2417 were characterized through interferometric observations. DCO+, N2H+, and N2D+ were used to trace the spatial distribution and physics of the cold regions of the envelope, while c-C3H2 and C2H from models of the chemistry are expected to trace the warm (UV-irradiated) regions. Results. The two sources show a number of striking similarities and differences. DCO+ consistently traces the cold material at the disk-envelope interface, where gas and dust temperatures are lowered due to disk shadowing. N2H+ and N2D+, also tracing cold gas, show low abundances toward VLA 1623−2417, but for IRAS 16293−2422, the distribution of N2D+ is consistent with the same chemical models that reproduce DCO+. The two systems show different spatial distributions c-C3H2 and C2H. For IRAS 16293−2422, c-C3H2 traces the outflow cavity wall, while C2H is found in the envelope material but not the outflow cavity wall. In contrast, toward VLA 1623−2417 both molecules trace the outflow cavity wall. Finally, hot core molecules are abundantly observed toward IRAS 16293−2422 but not toward VLA 1623−2417. Conclusions. We identify temperature as one of the key factors in determining the chemical structure of protostars as seen in gaseous molecules. More luminous protostars, such as IRAS 16293−2422, will have chemical complexity out to larger distances than colder protostars, such as VLA 1623−2417. Additionally, disks in the embedded phase have a crucial role in controlling both the gas and dust temperature of the envelope, and consequently the chemical structure.

Sign in / Sign up

Export Citation Format

Share Document