scholarly journals Analytical Pyrolysis of the Fungal Melanins from Ochroconis spp. Isolated from Lascaux Cave, France

2021 ◽  
Vol 11 (3) ◽  
pp. 1198
Author(s):  
Cesareo Saiz-Jimenez ◽  
Pedro M. Martin-Sanchez ◽  
Jose A. Gonzalez-Perez ◽  
Bernardo Hermosin
Keyword(s):  
Chemical Structure ◽  
Complex Structure ◽  
Homogentisic Acid ◽  
Analytical Pyrolysis ◽  
Pure Grade ◽  
Secondary Reactions ◽  
Diversity Of Components ◽  
Lascaux Cave ◽  
Fungal Melanins

Analytical pyrolysis is a tool widely used for investigating the nature of macromolecules. This technique has been applied with success for solving the chemical structure of geo- and biopolymers. However, with complex macromolecules, such as fungal melanins, analytical pyrolysis presents some drawbacks due to the fact that they rarely can be obtained in a pure grade and contains a mixture of polysaccharides, chitin, proteins, nucleic acids, and lipids, among other materials. Analytical pyrolysis permits the characterization of the compounds co-extracted or linked to the melanin. Nevertheless, our data revealed that under the conditions usually employed in the pyrolysis of melanins, the technique presented serious limitations due to the complex structure and diversity of components that suffer extensive thermal degradation through secondary reactions with the production of considerable number of artifacts. To the light of pyrolysis data, the melanin of Ochroconis spp. is not based on 3,4-dihydroxyphenylalanine (DOPA) or 1,8-dihydroxynaphthalene (DHN), and it is suggested that it could be a type of pyomelanin, based on the polymerization of homogentisic acid and other phenolic compounds.

Structural characterization of milled wood lignins from different eucalypt species

Holzforschung ◽  
2008 ◽  
Vol 62 (5) ◽  
Author(s):  
Jorge Rencoret ◽  
Gisela Marques ◽  
Ana Gutiérrez ◽  
David Ibarra ◽  
Jiebing Li ◽  
...  
Keyword(s):  
Eucalyptus Globulus ◽  
Chemical Structure ◽  
2D Nmr ◽  
Analytical Pyrolysis ◽  
Additional Information ◽  
Diaryl Ether ◽  
Heteronuclear Single Quantum Correlation ◽  
Relative Abundances ◽  
Type 3

Abstract The chemical structure of milled-wood lignins from Eucalyptus globulus, E. nitens, E. maidenii, E. grandis, and E. dunnii was investigated. The lignins were characterized by analytical pyrolysis, thioacidolysis, and 2D-NMR that confirmed the predominance of syringyl over guaiacyl units and only showed traces of p-hydroxyphenyl units. E. globulus lignin had the highest syringyl content. The heteronuclear single quantum correlation (HSQC) NMR spectra yielded information about relative abundances of inter-unit linkages in the whole polymer. All the lignins showed a predominance of β-O-4′ ether linkages (66–72% of total side-chains), followed by β-β′ resinol-type linkages (16–19%) and lower amounts of β-5′ phenylcoumaran-type (3–7%) and β-1′ spirodienone-type linkages (1–4%). The analysis of desulfurated thioacidolysis dimers provided additional information on the relative abundances of the various carbon-carbon and diaryl ether bonds, and the type of units (syringyl or guaiacyl) involved in each of the above linkage types. Interestingly, 93–94% of the total β-β′ dimers included two syringyl units indicating that most of the β-β′ substructures identified in the HSQC spectra were of the syringaresinol type. Moreover, three isomers of a major trimeric compound were found which were tentatively identified as arising from a β-β′ syringaresinol substructure attached to a guaiacyl unit through a 4-O-5′ linkage.

Preparation and Characterization of Soybean Oil-based Flame Retardant Rigid Polyurethane Foams Containing Phosphaphenanthrene Groups

2020 ◽  
Vol 17 (10) ◽  
pp. 760-771
Author(s):  
Qirui Gong ◽  
Niangui Wang ◽  
Kaibo Zhang ◽  
Shizhao Huang ◽  
Yuhan Wang
Keyword(s):  
Soybean Oil ◽  
Flame Retardant ◽  
Chemical Structure ◽  
Cell Structure ◽  
Polyurethane Foams ◽  
Limiting Oxygen Index ◽  
Rigid Polyurethane Foams ◽  
Degradation Activation Energy ◽  
Ft Ir

A phosphaphenanthrene groups containing soybean oil based polyol (DSBP) was synthesized by epoxidized soybean oil (ESO) and 9,10-dihydro-oxa-10-phosphaphenanthrene-10-oxide (DOPO). Soybean oil based polyol (HSBP) was synthesized by ESO and H2O. The chemical structure of DSBP and HSBP were characterized with FT-IR and 1H NMR. The corresponding rigid polyurethane foams (RPUFs) were prepared by mixing DSBP with HSBP. The results revealed apparent density and compression strength of RPUFs decreased with increasing the DSBP content. The cell structure of RPUFs was examined by scanning electron microscope (SEM) which displayed the cells as spherical or polyhedral. The thermal degradation and flame retardancy of RPUFs were investigated by thermogravimetric analysis, limiting oxygen index (LOI), and UL 94 vertical burning test. The degradation activation energy (Ea) of first degradation stage reduced from 80.05 kJ/mol to 37.84 kJ/mol with 80 wt% DSBP. The RUPF with 80 wt% DSBP achieved UL94 V-0 rating and LOI 28.3. The results showed that the flame retardant effect was mainly in both gas phase and condensed phase.

scholarly journals Fungal Melanins and Applications in Healthcare, Bioremediation and Industry

2021 ◽  
Vol 7 (6) ◽  
pp. 488
Author(s):  
Ellie Rose Mattoon ◽  
Radames J. B. Cordero ◽  
Arturo Casadevall
Keyword(s):  
Chemical Structure ◽  
Industrial Processes ◽  
Metal Chelation ◽  
Biological Functions ◽  
Societal Benefit ◽  
Potential Applications ◽  
Fungal Melanin ◽  
Human Use ◽  
Fungal Melanins ◽  
Isolated Species

Melanin is a complex multifunctional pigment found in all kingdoms of life, including fungi. The complex chemical structure of fungal melanins, yet to be fully elucidated, lends them multiple unique functions ranging from radioprotection and antioxidant activity to heavy metal chelation and organic compound absorption. Given their many biological functions, fungal melanins present many possibilities as natural compounds that could be exploited for human use. This review summarizes the current discourse and attempts to apply fungal melanin to enhance human health, remove pollutants from ecosystems, and streamline industrial processes. While the potential applications of fungal melanins are often discussed in the scientific community, they are successfully executed less often. Some of the challenges in the applications of fungal melanin to technology include the knowledge gap about their detailed structure, difficulties in isolating melanotic fungi, challenges in extracting melanin from isolated species, and the pathogenicity concerns that accompany working with live melanotic fungi. With proper acknowledgment of these challenges, fungal melanin holds great potential for societal benefit in the coming years.

Optimization and characterization of flavonoids extracted from Cannabis sativa fibers

2021 ◽  
pp. 004051752110277
Author(s):  
Qilu Cui ◽  
Jiawei Li ◽  
Chongwen Yu
Keyword(s):  
Chemical Structure ◽  
Cannabis Sativa ◽  
Ethanol Concentration ◽  
Extraction Process ◽  
Test Results ◽  
Hemp Fiber ◽  
Hemp Fibers ◽  
Structure Surface ◽  
Degumming Process

In this paper, the extraction process of flavonoids from hemp fibers was studied. Response surface methodology (RSM) analysis of the extraction parameters indicated that optimized results would be ethanol concentration 76 vol.%, bath ratio 1:50, and reaction time 139 min; therefore, an optimal extraction rate of flavonoids of 0.2275% can be obtained. The chemical structure, surface morphology and element composition of flavonoid extracts were analyzed. The test results indicated that hemp extract contains flavonoids, which can be used to extract flavonoids from hemp fiber, so as to comprehensively develop hemp fiber and reduce the discharge of waste liquid in the traditional degumming process.

scholarly journals Isolation and chemical structure characterization of enzymatic lignin frompopulus deltoidswood

2013 ◽  
Vol 130 (1) ◽  
pp. 710-710
Author(s):  
Ali Abdulkhani ◽  
Alinaghi Karimi ◽  
Ahmad Mirshokraie ◽  
Yahya Hamzeh ◽  
Nathalie Marlin ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Structure Characterization

Characterization of Hydrocarbon Emissions from Green Sand Foundry Core Binders by Analytical Pyrolysis

2007 ◽  
Vol 41 (22) ◽  
pp. 7922-7927 ◽  
Author(s):  
Yujue Wang ◽  
Fred S. Cannon ◽  
Magda Salama ◽  
Jeff Goudzwaard ◽  
James C. Furness
Keyword(s):  
Hydrocarbon Emissions ◽  
Analytical Pyrolysis ◽  
Green Sand

Synthesis and Characterization of Alkeyl Imidazolium Ionic Liquids

2014 ◽  
Vol 1048 ◽  
pp. 452-455
Author(s):  
Qiang Wang ◽  
Shi Dong Wang ◽  
Ming Chen Qi ◽  
Shu Liang Zang
Keyword(s):  
Ionic Liquids ◽  
Chemical Structure ◽  
Direct Synthesis ◽  
Synthesis Method ◽  
Structure And Properties ◽  
Spectra Analysis ◽  
Infrared Spectrometer ◽  
Liquid Salts ◽  
Structure Of Matter

Two new imidazole ionic liquid salts, 1-allyl-3-methylimidazolium chloride ([AMIM]Cl) and 1-allyl-3-methy-imidazolium hydrogen sulfate ([EMIM]HSO4), were synthesized with direct synthesis and two-step synthesis method, using a viscosity meter, PH meter, conductivity meter, densitometer, infrared spectrometer determined its chemical structure and properties. The results show that two ionic liquids in the range is slightly different, the trend is roughly same. As the temperature increases, the viscosity decreases, PH gradually increased, the density decreases slightly, can be regarded as constant, the conductivity gradually increased. Ionic liquids of the two IR spectra analysis show its structure and synthetic route consistent with the structure of matter.

Further specificity characterization of von Willebrand factor inhibitors developed in two patients with severe von Willebrand disease

Blood ◽  
1988 ◽  
Vol 72 (1) ◽  
pp. 116-120 ◽  
Author(s):  
MF Lopez-Fernandez ◽  
R Martin ◽  
C Lopez-Berges ◽  
F Ramos ◽  
N Bosch ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Complex Structure ◽  
Relative Proportion ◽  
Von Willebrand Disease ◽  
Rabbit Antibody ◽  
Human Factor Viii ◽  
Rabbit Polyclonal Antibody ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Circulating inhibitors against von Willebrand factor (vWF) that show the properties of heterologous IgG antibodies have been described in a few patients with severe von Willebrand disease (vWD). The present study provides further characterization of inhibitors from two patients with severe vWD. Inhibitors in both, like polyclonal rabbit antibody, detected all sizes of multimers and the complex structure of each multimer from platelets and plasma of normal individuals as well as from plasma of patients with IIA, IIB, and IIC vWD. Both inhibitors and the rabbit antibody reacted mainly with the intact 225-Kd vWF subunit and the 189-H and 140-Kd fragments in contrast to monoclonal antibodies specific for vWF fragments that detected a higher relative proportion of 176-Kd fragment. Furthermore, all these antibodies recognized fragment III, although one inhibitor and rabbit polyclonal antibody reacted poorly and the other inhibitor did not react at all with reduced fragment II of vWF digested with Staphylococcus aureus V-8 protease. These data suggest that although human inhibitors from severe vWD patients may behave, to some extent, as polyclonal heterologous antibodies against native vWF, the former show striking differences in their target specificity as well as a much broader specificity than that described for human factor VIII inhibitors.

Synthesis and characterization of novel sulfonated polyimide with varying chemical structure for fuel cell applications

2018 ◽  
Vol 319 ◽  
pp. 141-147 ◽  
Author(s):  
Khurram Liaqat ◽  
Wajid Rehman ◽  
Shaukat Saeed ◽  
Muhammad Waseem ◽  
Srosh Fazil ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Chemical Structure ◽  
Synthesis And Characterization ◽  
Sulfonated Polyimide
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