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Gotowa bibliografia na temat „Lignin distribution”

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Data publikacji: 20 lipca 2024

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Artykuły w czasopismach na temat "Lignin distribution"

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Ház, Aleš, Michal Jablonský, Igor Šurina, František Kačík, Tatiana Bubeníková i Jaroslav Ďurkovič. "Chemical Composition and Thermal Behavior of Kraft Lignins". Forests 10, nr 6 (3.06.2019): 483. http://dx.doi.org/10.3390/f10060483.

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Lignin has great potential for utilization as a green raw material or as an additive in various industrial applications, such as energy, valuable chemicals, or cost-effective materials. In this study, we assessed a commercial form of lignin isolated using LignoBoost technology (LB lignin) as well as three other types of lignin (two samples of non-wood lignins and one hardwood kraft lignin) isolated from the waste liquors produced during the pulping process. Measurements were taken for elemental analysis, methoxyl and ash content, higher heating values, thermogravimetric analysis, and molecular weight determination. We found that the elemental composition of the isolated lignins affected their thermal stability, activation energies, and higher heating values. The lignin samples examined showed varying amounts of functional groups, inorganic component compositions, and molecular weight distributions. Mean activation energies ranged from 93 to 281 kJ/mol. Lignins with bimodal molecular weight distribution were thermally decomposed in two stages, whereas the LB lignin showing a unimodal molecular weight distribution was decomposed in a single thermal stage. Based on its thermal properties, the LB lignin may find direct applications in biocomposites where a higher thermal resistance is required.
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Huang, Yang, Chenhuan Lai, Shaolong Sun, Qiang Yong, Brian K. Via i Maobing Tu. "Organosolv lignin properties and their effects on enzymatic hydrolysis". BioResources 15, nr 4 (12.10.2020): 8909–24. http://dx.doi.org/10.15376/biores.15.4.8909-8924.

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Lignin plays a crucial role in enzymatic hydrolysis of lignocellulosic biomass. To evaluate the correlation between lignin properties and its effects on enzymatic hydrolysis, five organosolv lignins (OLs) were isolated from woody biomass, and their physico-chemical properties and structural features were characterized. The effects of OL addition on enzymatic hydrolysis of microcrystalline cellulose (pure cellulose) were assessed first, which showed their disparate effects. The addition of three OLs increased the 72 h hydrolysis yield by 7.4% to 10.1%, while the addition of other two OLs reduced the 72 h hydrolysis yield by 3.2% to 20.4%. A strong correlation between the enzyme distribution coefficient on lignins and the 72 h hydrolysis yields indicated that the enzyme-lignin interaction played a significant role in determining the lignin effects. More importantly, a correlation between lignin properties (hydrophobicity, zeta potential, and particle size) and the enzyme distribution coefficient was established. Identifying the key lignin properties will give insights to reduce the lignin inhibition by altering the lignin properties, thereby promoting enzymatic hydrolysis of lignocellulose.
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Damayanti, Damayanti, Yeni Ria Wulandari i Ho-Shing Wu. "Product Distribution of Chemical Product Using Catalytic Depolymerization of Lignin". Bulletin of Chemical Reaction Engineering & Catalysis 15, nr 2 (22.05.2020): 432–53. http://dx.doi.org/10.9767/bcrec.15.2.7249.432-453.

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Lignin depolymerization is a very promising process which can generate value-added products from lignin raw materials. The main objective of lignin depolymerization is to convert the complex molecules of lignin into small molecules. Nevertheless, lignin is natural polymer which the molecules of lignin are extremely complicated due to their natural variability, and it will be a big challenge to depolymerize lignin, particularly high water yield. The various technology and methods are developed to depolymerize lignin into biofuels or bio chemical products including acid/base/metallic catalyzed lignin depolymerization, pyrolysis of lignin, hydroprocessing, and gasification. The distribution and yield of chemical products depend on the reaction operation condition, type of lignin and kind of catalyst. The reactor type, product distributions and specific chemicals (benzene, toluene, xylene, terephthalic acid) production of lignin depolymerization are intensive discussed in this review. Copyright © 2020 BCREC Group. All rights reserved
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Thring, Ronald W., Esteban Chornet i Ralph P. Overend. "Fractionation of woodmeal by prehydrolysis and thermal organosolv. Alkaline depolymerization, chemical functionality, and molecular weight distribution of recovered lignins and their fractions". Canadian Journal of Chemistry 71, nr 6 (1.06.1993): 779–89. http://dx.doi.org/10.1139/v93-103.

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Thermal organosolv glycol lignins and their fractions have been characterized by means of elemental composition, molecular weight distribution, and 1H and 13C NMR spectroscopy. Fractionation of each lignin by sequential solvent extraction produced fractions of increasing molecular weight and polydispersity. Structures in the highest molecular weight fractions were found to be linked by a high proportion of β-O-4 type bonds, whilst the lowest molecular weight fractions consisted of a high content of saturated aliphatic side-chain structures. A noticeable difference in the content of carbohydrate contaminants in both starting lignins indicated the formation of relatively stable lignin–carbohydrate complexes, especially in the lignin recovered from pretreated wood. In addition, depolymerization of the lignins and their fractions to monomeric compounds was explored using alkaline hydrolytic and nitrobenzene oxidative routes. The highest molecular weight fractions from each lignin were identified as the best candidates for production of useful monomeric phenolic compounds.
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El Mansouri, Nour-Eddine, Qiaolong Yuan i Farong Huang. "Characterization of alkaline lignins for use in phenol-formaldehyde and epoxy resins". BioResources 6, nr 3 (19.05.2011): 2647–62. http://dx.doi.org/10.15376/biores.6.3.2647-2662.

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Besides polyurethanes and polyesters, phenolic and epoxy resins are the most prominent applications for technical lignins in thermosetting materials. To evaluate the potential application of lignin raw materials in phenol formaldehyde and epoxy resins, three types of alkaline lignins were characterized in terms of their structures and thermal properties. The lignin samples analyzed were kraft lignin (LIG-1), soda–rice straw lignin (LIG-2), and soda-wheat straw lignin (LIG-3). FTIR and 1H-NMR methods were used to determine their structure. Gel permeation chromatography (GPC) was used to determine the molecular weight distribution (MWD). Differential scanning calorimetry (DSC) was used to measure the glass transition temperature (Tg), and thermogravimetric analysis (TGA) to determine the thermal stability of lignin samples. Results showed that kraft lignin (LIG-1) has moderate hydroxyl-group content, is rich in G-type units, and has good thermal stability. These properties make it more suitable for direct use in phenol formaldehyde resins, and it is therefore a good raw material for this purpose. The alkaline soda-rice straw lignin (LIG-2) with a high hydroxyl-group content and excellent thermal stability is most suited to preparing lignin-based epoxy resins.
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Koda, Keiichi, Keiichi Koda, Armindo R. Gaspar, Liu Yu, Liu Yu, Liu Yu i Dimitris S. Argyropoulos. "Molecular weight-functional group relations in softwood residual kraft lignins". Holzforschung 59, nr 6 (1.11.2005): 612–19. http://dx.doi.org/10.1515/hf.2005.099.

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Abstract An integrated picture of the distribution of functional groups should be provided as a function of molecular size within residual kraft lignins. With this goal we developed a reliable and reproducible method for determination of the molecular weight and molecular weight distribution of residual kraft lignins (RKLs) over the whole delignification range. In general, our data indicate that for reliable measurement of the molecular weight and its distribution of residual lignin in pulps, the lignin-carbohydrate bonds have to be cleaved prior to size exclusion chromatography. The recently developed method for isolating residual lignins, which involves cellulolytic treatment followed by a mild acid hydrolysis step, was found to be the most suitable approach to achieve this. The molecular weight and polydispersity of all RKLs decreased as a function of delignification. As anticipated, the observed decrease in molecular weight was clearly reflected in the concomitantly decreasing amount of β-O-4 structural linkages present. Similarly, the total phenolic hydroxyl content increased as the molecular weight of the RKLs decreased during kraft pulping. Despite the smaller size of the lignin remaining on the kraft fiber at the end of delignification, the preponderance of condensed phenolic structures within these lignins offers an explanation for delignification problems during bleaching.
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Duarte, A. P., D. Robert i D. Lachenal. "Eucalyptus globulus Kraft Pulp Residual Lignin. Part 2. Modification of Residual Lignin Structure in Oxygen Bleaching". Holzforschung 55, nr 6 (6.11.2001): 645–51. http://dx.doi.org/10.1515/hf.2001.105.

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Summary Residual lignins were isolated from unbleached and oxygen-bleached Eucalyptus kraft pulps by acid hydrolysis. The structural changes and degradation of residual lignin occurring during kraft pulping and oxygen bleaching were followed and identified by elemental analysis, residual carbohydrate analysis, molecular mass distribution, as well as qualitative and quantitative solution 13C NMR. The dissolved lignins in the kraft cooked and oxygen bleached liquors were also studied and compared with the corresponding residual lignins. Milled wood lignin treated under acid hydrolysis conditions served as a reference for the structural comparison. The results show that etherified syringyl structures were quite resistant towards degradation in the oxygen bleaching, causing little depolymerisation in residual lignin and a small increase in carboxylic acid content, but producing appreciable amounts of saturated aliphatic methylene groups.
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Thring, R. W., i S. L. Griffin. "The heterogeneity of two Canadian kraft lignins". Canadian Journal of Chemistry 73, nr 5 (1.05.1995): 629–34. http://dx.doi.org/10.1139/v95-081.

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Two kraft lignins, one precipitated with carbon dioxide and the other with sulphuric acid, have been fractionated into three distinct fractions by sequential extraction using organic solvents of increasing hydrogen-bonding capacity. The lignins and fractions were comparatively characterized in terms of yield, methoxyl group content, molecular weight distribution, and 13C NMR spectroscopy. For a given lignin, the fractions showed differences in yield, composition, and chemical structure. A significant portion (21%) of the carbon dioxide precipitated kraft lignin is composed of ethyl acetate soluble material of low molecular weight. This fraction, which is richer in guaiacyl moieties than the other fractions, is virtually absent in the sulphuric acid precipitated kraft lignin. The occurrence of "tails" in the high molecular weight fraction, especially from the carbon dioxide precipitated kraft lignin, suggests the presence of material of very high molecular weight. Data from 13C NMR spectroscopy does little to elucidate the nature or origin of the material causing these tails. Keywords: kraft lignins, heterogeneity, fractionation, characterization.
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Bergamasco, Sara, Florian Zikeli, Vittorio Vinciguerra, Anatoly Petrovich Sobolev, Luca Scarnati, Giorgio Tofani, Giuseppe Scarascia Mugnozza i Manuela Romagnoli. "Extraction and Characterization of Acidolysis Lignin from Turkey Oak (Quercus cerris L.) and Eucalypt (Eucalyptus camaldulensis Dehnh.) Wood from Population Stands in Italy". Polymers 15, nr 17 (29.08.2023): 3591. http://dx.doi.org/10.3390/polym15173591.

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Acidolysis lignins from the species Quercus cerris L. and Eucalyptus camaldulensis Dehnh. were isolated and characterized using high pressure size exclusion chromatography (HP-SEC), Fourier-transform (FTIR) infrared spectroscopy, analytical pyrolysis–gas chromatography–mass spectrometry (Py-GCMS), and two-dimensional heteronuclear single quantum coherence (2D HSQC) NMR spectroscopy. The acidolysis lignins from the two different species varied in chemical composition and structural characteristics, with Q. cerris L. lignin having a higher S/G ratio and higher molar mass averages with a bimodal molar mass distribution. The different analytical techniques FTIR spectroscopy, Py-GCMS, and 2D NMR spectroscopy provided consistent results regarding the S/G ratio of the lignins from the two wood species. Based on the determined high S/G ratio of both oak and eucalypt lignin, the two wood sources could be promoted as substrates for efficient lignin isolation in modern forest biorefineries in order to develop innovative lignin-based value-added biorefinery products.
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Vallejos, María E., Fernando E. Felissia, Aprigio A. S. Curvelo, Marcia D. Zambon, Luis Ramos i María C. Area. "Chemical and physico-chemical characterization of lignins obtained from ethanol-water fractionation of bagasse". BioResources 6, nr 2 (21.02.2011): 1158–71. http://dx.doi.org/10.15376/biores.6.2.1158-1171.

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Organosolv lignins can replace petroleum chemicals such as phenol either partially or totally in various applications. Eight lignins, seven of which corresponded to the ethanol-water fractionation of bagasse and the other to a reference lignin (Alcell®) were analyzed with the aim to evaluate their chemical and physicochemical characteristics. The purity of the lignin fractions was determined by high pressure liquid chromatography (HPLC) and by ash content. Fourier Transform-Infrared Spectroscopy (FTIR) techniques and differential UV spectroscopy were applied to identify the chemical groups in the lignin samples. The molecular weight distribution was determined by size exclusion chromatography (HPSEC). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques were used to determine the mass loss due to the high temperature treatment. The lignins studied showed the presence of p-hydroxyphenyl (H unit) and a greater proportion of guaiacyl (G unit) moieties, lower purity, similar or greater amount of phenolic hydroxyl groups, and higher degradation temperatures, than the Alcell® lignin.
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Rozprawy doktorskie na temat "Lignin distribution"

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Reeves, Alison Dawn. "The distribution and behaviour of lignin in the estuarine environment". Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.237510.

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寶詠恩 i Vivienne Valerie Claire Bucher. "Distribution of lignin-modifying enzymes among aquatic fungi and theirability to degrade lignocellulose substrates". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31243988.

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Atadana, Frederick Williams. "Catalytic Pyrolysis of Cellulose, Hemicellulose and Lignin Model Compounds". Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31251.

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The effect of HZSM-5 catalyst and NaOH pretreatment on the product distribution and bio oil properties from pyrolysis of cellulose, hemicellulose and lignin model compounds was investigated at 450 °C. NaOH pretreated and untreated cellulose was pyrolyzed on sand and the HZSM-5 catalysts; VPISU001 HZSM-5, BASF HZSM-5, and Sud-Chemie HZSM-5. The pyrolysis of cellulose on BASF and Sud-Chemie HZSM-5 catalysts increased the yields of the organic liquid fraction, total liquid and char while decreasing the gas yields. However the catalyst decreased the organic and char yields while increasing the water yields but there was no change in gas yields. The NaOH treatment caused a decrease in the organic and total oil yields relative to the control but the char yield increased. The change in gas yields was not significant. The characterization of the oils using FTIR and 13Câ nmr showed that, the VPISU001 HZSM-5 with and without NaOH pretreatment caused elimination of the levoglucosan fraction while increasing the aromatic fraction. The NaOH pretreated cellulose pyrolyzed on sand reduced the levoglucosan groups while increasing the aromatic fraction of the bio oil. In the hemicellulose studies, birchwood xylan and NaOH treated xylan samples were pyrolyzed on sand and VPISU001 HZSM-5 catalyst. The organic liquid yields were very low and ranged from 3.3 wt% to 7.2 wt%, the water yields ranged from 17.8-25.7 wt%, the char yield were 17.8-25 wt% and gas yield were 40.9-49.6 wt%. The HZSM-5 catalysts increased the water and gas yields and produced the lowest char yield. NaOH pretreatment produced the lowest water yield while the char yield was the highest. The combined effect of NaOH pretreatment and HZSM-5 produced the lowest organic yield and highest char yield. The FTIR and 13C-nmr analyses of the organic liquids showed that the HZSM-5 catalyst promoted the formation of aromatic products, while the NaOH pretreatment promoted the formation of aliphatic hydrocarbons. The combined effect of NaOH pretreatment and HZSM-5 catalyst seem to promote the formation of anhydrosugars. The main gases evolved were CO, CO2 and low molecular weight hydrocarbons. The HZSM-5 catalyst promoted CO formation while NaOH pretreatment promoted CO2. The HZSM-5 catalyst produced the highest yield of low molecular weight hydrocarbon gases. The lignin and model compounds studies involved using low molecular weight kraft lignin, guaiacol, and syringol which were pyrolyzed on sand and VPISU001 HZSM-5 catalyst at 450 °C. The kraft lignin pyrolysis produced low liquid and gas yields and high char yields. The HZSM-5 catalysts increased the water yield and decreased the organic liquid yield. NaOH pretreatment increased the char yield and decreased the liquid products. NaOH and the HZSM-5 catalyst together decreased the char and increased the gas yields. The 13C-nmr and FTIR analysis showed that NaOH pretreatment promoted the formation of mainly guaiacol while the HZSM-5 catalyst formed different aromatic components. NaOH pretreatment promoted the formation of more CO2 than CO whilst HZSM-5 catalyst promoted the formation of more CO than CO2. Methane formation was enhanced by NaOH pretreatment. Other hydrocarbon gases were however enhanced by the HZSM-5 catalysts. Pyrolysis of the model compounds on the HSZM-5 catalyst showed an increase in pyrolytic water. The HZSM-5 catalyst promoted demethylation in syringol pyrolysis as compared to guaiacol.


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Morel, Oriane. "Characterization of the spatial distribution of lignins in plant cell walls using chemical reporters and Raman". Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILS118.

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La lignine est un polymère polyphénolique de la paroi cellulaire qui intervient dans de nombreux aspects de la croissance et du développement des plantes supérieures. En tant que composant majeur de la biomasse lignocellulosique, elle présente également un intérêt économique. Bien que la biosynthèse du polymère de la lignine soit relativement bien comprise, nous avons besoin d'en savoir plus sur la façon dont les changements (quantité/structure) des autres polymères de la paroi cellulaire (par exemple, la cellulose, les hémicelluloses, les pectines) affectent la production de lignine. Afin de fournir plus d'informations sur cette question, nous avons mis en œuvre une approche en deux phases basée sur l'utilisation de l'imagerie biologique. La première phase a consisté à développer/améliorer différentes techniques d'imagerie complémentaires à haute résolution. Nous avons tout d'abord développé une nouvelle approche ratiométrique quantitative (REPRISAL) basée sur la segmentation paramétrique/intelligence artificielle d'images de microscopie confocale obtenues par la chimie bio-orthogonale des rapporteurs chimiques de la lignine (click chemistry). Cette méthodologie nous a permis de cartographier précisément la capacité de lignification des différentes couches de la paroi cellulaire (coin cellulaire, lamelle moyenne composée et paroi cellulaire secondaire) chez les plantes Arabidopsis WT et le mutant prx64. Dans un deuxième temps, nous avons modifié l'algorithme de segmentation REPRISAL afin de pouvoir l'utiliser pour cartographier les niveaux relatifs de lignine de la paroi cellulaire déterminés par la technique de fluorescence ratiométrique de la safranine-O. Enfin, nous avons utilisé l'imagerie Raman pour comparer la capacité de trois méthodes analytiques multivariées différentes (non-mixage, analyse en grappes et correspondance orthogonale) à fournir des informations spatiales détaillées sur la distribution des différents polymères dans les parois cellulaires des plantes. Dans la deuxième phase, nous avons utilisé les techniques d'imagerie développées/améliorées pour analyser si les modifications des hémicelluloses de la paroi cellulaire affectent la lignification chez le mutant irx9 d'Arabidopsis. Nos résultats ont démontré que les changements dans la distribution des hémicelluloses de la paroi cellulaire modifient effectivement le processus de lignification, en particulier dans les parties les plus jeunes de la tige florale de la plante. La transcriptomique ciblée de certains gènes de la paroi cellulaire suggère que les changements observés pourraient être liés à l'induction d'une réponse de défense. Globalement, les techniques développées dans le cadre de cette thèse devraient s'avérer précieuses pour les études futures de la dynamique des parois cellulaires. Les résultats obtenus sur le mutant irx9 donnent un nouvel aperçu des relations dynamiques qui existent entre les différents polymères de la paroi cellulaire des plantes
Lignin is a polyphenolic polymer of the cell wall involved in many aspects of growth and development in higher plants. As a major component of lignocellulosic biomass, it is also of economic interest. Although the biosynthesis of the lignin polymer is relatively well understood, we need to know more about how changes (quantity/structure) to other cell wall polymers (e.g., cellulose, hemicelluloses, pectins) affect lignin production. To provide more information on this question we implemented a two-phase approach based on the use of biological imaging. The first phase involved the development/improvement of different high-resolution complementary imaging techniques. We firstly developed a novel quantitative ratiometric approach (REPRISAL) based on the parametric/artificial intelligence segmentation of confocal microscopy images obtained by lignin chemical reporter bio-orthogonal chemistry. This methodology allowed us to precisely map the lignification capacity of different cell wall layers (cell corner, compound middle lamella and secondary cell wall) in Arabidopsis WT plants and the prx64 mutant. In a second development, we modified the REPRISAL segmentation algorithim thereby enabling it to be used to map relative cell wall lignin levels determined by the ratiometric safranin-O fluorescence technique. Finally, we used Raman imaging to compare the ability of three different multivariate analytical methods (unmixing, cluster analysis and orthogonal matching) to provide detailed spatial information about the distribution of different polymers in plant cell walls. In the second phase we used the developed/improved imaging techniques to analyse whether changes to cell wall hemicelluloses affect lignification in the Arabidopsis irx9 mutant. Our results demonstrated that changes in the distribution of cell wall hemicelluloses do indeed modify the lignification process, particularly in the younger parts of the plant floral stem. Targeted transcriptomics of selected cell wall genes suggested that the observed changes could be related to the induction of a defence response. Overall, the techniques developed within the framework of this thesis should prove valuable for future studies of cell wall dynamics. The results obtained on the irx9 mutant provide a novel insight into the dynamic relationships that exist between different polymers of the plant cell wall
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Chedid, Fadia. "Determination of absolute molecular mass distribution and other structural properties of kraft lignin samples : Investigation using SEC in combination with MALDI-TOF-MS and Py-GC/MS". Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-105449.

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Lignin is an aromatic macromolecule present in wood and also a by-product in the process of making paper. For a long time, this by-product has been of no interest except for combustion in the recovery boilers for production of energy. Nowadays, however, there is a great interest of finding an alternative use of lignin, not the least the type obtained from the paper industry black liquor with the process called LignoBoost. Although there is some interesting research concerning the salvaging of lignin, for example as a source for new materials, the chemical constitution and properties are still not fully investigated. The purpose of this work was therefore to develop a method for a better determination of the molecular mass distribution (MMD) of both hardwood and softwood kraft lignins from the biorefinery. The method of choice is a combination of size-exclusion-chromatography (SEC), where the lignin is fractionated, followed by an analysis of the fractions on a matrix-assisted laser desorption ionization time-of-flight mass spectroscopy instrument (MALDI-TOF-MS). Furthermore, the chemical composition of high and low molecular fractions of LignoBoost lignin was determined with pyrolysis gas chromatography mass spectrometry (Py-GC/MS). It was shown that the MMD determination method of lignin used until now is sometimes insufficient. Therefore, two separate calibration methods were developed for softwood and hardwood kraft lignins. Included in the method development was also an investigation of the necessity of acetylation when analyzing lignin on SEC using tetrahydrofuran (THF) as the mobile phase. It was found that for softwood lignin from the LignoBoost process, this procedure is necessary while the corresponding hardwood lignin does not require an acetylation. The chemical composition, determined with Py-GC/MS, of hardwood and softwood lignin did not present any significant differences between the structures of high and low molecular lignin. However, differences were found concerning extractives content in lignin preparations from softwood. This thesis was performed at Innventia AB.
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Dria, Karl Jay. "Carbon and nitrogen distribution and processes in forest and agricultural ecosystems a study involving solid- and liquid-state NMR and pyrolysis GC/MS /". Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1085700625.

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Thesis (Ph. D.)--Ohio State University, 2004.
Title from first page of PDF file. Document formatted into pages; contains xv, 214 p.; also includes graphics (some col.). Includes bibliographical references (p. 194-206). Available online via OhioLINK's ETD Center
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Sjöberg, John. "Characterization of chemical pulp fiber surfaces with an emphasis on the hemicelluloses". Doctoral thesis, KTH, Fibre and Polymer Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3462.

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Main, Oscar. "Optimising forage maize's digestible yield under contrasted environments". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASB019.

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Le maïs occupe une place centrale dans le système fourrager français, son rendement et sa valeur énergétique étant deux critères clés pour l'inscription des variétés hybrides de maïs au catalogue officiel français. Des recherches antérieures ont montré une corrélation directe entre la valeur énergétique et la digestibilité de la matière sèche (MS), influencée par la digestibilité de la paroi, elle-même affectée par le déficit hydrique. Des études sur des lignées de maïs ont montré que le déficit hydrique sévère augmente la digestibilité de la MS et de la paroi, liées à une diminution de la teneur en lignine et à des changements dans sa distribution tissulaire. Cependant, comme la teneur en lignine a déjà été fixée dans les variétés hybrides, elle semble avoir peu de potentiel pour améliorer davantage la digestibilité de la paroi. Pour explorer d'autres cibles et l'impact du déficit hydrique sur ces caractères, ce travail de thèse a été mené dans le cadre du projet Carnot Plant2Pro INRAE-ARVALIS MAMMA MIA. Des variétés de maïs hybrides modernes, représentatifs du marché français actuel (maïs S0-S1 très précoces à précoces), ont été cultivés pendant deux ans dans seize conditions environnementales contrastées, dont six en conditions d'irrigation contrôlée. Tout d'abord, un indice de stress (SID) simple mais robuste a été établi, tenant compte du déficit hydrique du sol et de la température de l'air. Ce SID s'est révélé être un outil crucial en classant les différents environnements, mettant en évidence l'impact d'un stress sévère dû à des températures élevées sur la digestibilité de la MS par rapport à des conditions de stress modéré. Pour être en mesure d'étudier une large gamme de conditions environnementales, plusieurs équations de prédiction par spectroscopie proche infrarouge (NIRS) ont également été développées, capables de prédire de manière robuste et précise des caractères de la paroi et leurs relations, similaires à celles mesurées en biochimie au laboratoire. Bien que ces équations se révèlent suffisamment robustes pour être utilisées dans les programmes de sélection, une vigilance s'impose quant à l'exactitude des prédictions en conditions de stress, en particulier dans le cas des variétés hybrides où la gamme de variation des caractères est souvent limitée. L'ensemble des données obtenues a ensuite permis une analyse multi-échelle, intégrant des caractères agroclimatiques, agronomiques, biochimiques et histologiques, ainsi que des données expérimentales in sacco obtenues sur des vaches fistulées. Des cibles biochimiques et histologiques ont pu être proposées pour améliorer la qualité du maïs fourrager en fonction de l'intensité du stress. Nous avons montré qu'en condition de stress sévère, bien que la production d'épis diminue significativement, la digestibilité de la MS peut être maintenue grâce à une augmentation de la digestibilité de la paroi, due à une réduction de la teneur en acides p-hydroxycinnamique, alors que la teneur en lignine reste stable comme attendu. Nous avons également montré qu'en condition de stress modéré les caractères histologiques jouent un rôle aussi important que les caractères biochimiques, mais qu'une fois qu'un seuil est atteint, seuls les caractères biochimiques modulent les variations de la digestibilité de la paroi. Une fenêtre environnementale a donc pu être mise en évidence où le rôle accru de la distribution de la lignine aux côtés des caractères biochimiques permet une augmentation du rendement digestible. Ainsi, les agriculteurs pourraient exploiter cette fenêtre pour augmenter la productivité, en régulant l'irrigation en condition de sécheresse modérée et en intégrant le SID dans un outil de gestion de l'irrigation
Maize stands as a pillar of the French forage system, with its yield and silage feeding value serving as key criteria for the registration of maize hybrid varieties in the official French catalogue. Previous research on this topic has revealed a direct correlation between silage feeding value and dry matter (DM) digestibility, which is, in turn, constrained by cell wall (CW) digestibility and significantly affected by water deficit. Studies on maize inbred lines have shown that under severe water deficit conditions, both DM and CW digestibilities increase. This increase correlates with a decrease in lignin content and changes in lignin distribution. However, it is noteworthy that breeding efforts have already fixed lignin content in hybrid varieties. Therefore, lignin content is unlikely to be a source of future digestibility improvement. To explore other CW targets and the impact of water deficit on these traits, this PhD study was conducted as part of the Carnot Plant2Pro INRAE-ARVALIS MAMMA MIA project. We grew a range of modern forage maize hybrids representative of the current S0-S1 (very-early to early flowering earliness) French market for two years under sixteen contrasted environmental conditions, including six in controlled irrigation conditions. First, we established a simple but robust stress index (SID) that considers the water deficit in the soil and the air temperature. This SID provided a key environmental ranking tool, highlighting severe stress due to high temperature that significantly impacted DM digestibility compared to moderate stress conditions. Secondly, to encompass a wide range of environmental conditions in biochemical quantifications, we developed several predictive near-infrared spectroscopy (NIRS) equations capable of robustly and accurately predicting fine cell wall traits and relationships, mirroring levels observed in laboratory experiments. While these equations prove sufficiently robust for use in selection programs, we emphasize the need for vigilance in accurately estimating prediction accuracy under stress conditions, particularly in equations applied to hybrid material where trait variation ranges are often limited. The core dataset of this work enabled a multiscale analysis, integrating agroclimatic, agronomic, biochemical, and histological traits, along with in sacco experimental data on cows. We proposed biochemical and histological traits to improve the quality of forage maize depending on stress intensity. We demonstrated that under severe stress, ear production decreases significantly, but DM digestibility can be maintained by increasing CW digestibility. This boost in CW digestibility was due to a reduction in p-hydroxycinnamic acid content, while lignin content remained stable, as anticipated. The significance of lignin distribution increased with the severity of stress, reaching an extreme threshold where biochemical parameters solely account for digestibility variations. This two-threshold model presents a window of opportunity located at the first threshold between non-stressed and moderately stressed environments, where the increased role of lignin distribution alongside biochemical traits enabled an increase in digestible yield. By controlling irrigation doses in the field under moderate drought conditions and integrating the SID into an irrigation management tool, farmers could exploit this window to increase productivity
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Burlat, Vincent. "Étude immunocytochimique de la distribution ultrastructurale des lignines dans la paille de blé et de son influence sur le mode d'action des champignons ligninolytiques : application aux pâtes à papier". Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10100.

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Les champignons basidiomycetes filamenteux sont parmi les plus performants pour la degradation de la lignine. Ils doivent leur activite a un complexe enzymatique au sein duquel trois enzymes jouent un role fondamental dans les mecanismes d'oxydation de la lignine. Il s'agit des lignines peroxydases (lip), des manganese peroxydases (mnp) et des laccases (lac). Trois souches fongiques, phlebia radiata (lip, mnp, lac), ceriporiopsis subvermispora (mnp, lac) et pleurotus eryngii (mnp, lac), ont ete selectionnees pour leur aptitude a degrader la paille de ble, dans le but d'utiliser les enzymes les plus efficaces pour la delignification de pates papetieres de paille. L'etude a ete realisee en microscopie electronique a transmission dans le but de montrer comment la nature du substrat et l'equipement enzymatique influencaient la degradation. L'organisation ultrastructurale des tissus lignifies constituant la paille de ble a tout d'abord ete etudiee. Pour cela nous avons mis en uvre de nouveaux marqueurs immunologiques des lignines. La caracterisation des differents types de lignine a mis en evidence des specificites liees a la nature des monolignols constitutifs et aussi a la nature des liaisons inter-unites de type condense et non-condense. L'application de ces marqueurs immunocytochimiques a revele l'heterogeneite de la distribution qualitative des lignines dans les differents tissus et au sein d'un meme type cellulaire. Dans une seconde partie du travail, l'aptitude des champignons a liberer leur enzymes lorsqu'ils se developpent dans la paille a ete etudiee. A l'aide d'anticorps diriges respectivement contre les mnp et les lac nous avons pu suivre la production, par les champignons, de leur enzymes extracellulaires. Ces enzymes sont excretees de facon concomitante au voisinage du site de degradation. Elles n'apparaissent pas dans les hyphes au contact des tissus sains. A des stades de degradation plus avances, l'excretion des mnp et lac a pu etre reliee a la nature de la lignine localement exposee a la degradation. Il a pu etre etabli que l'excretion etait plus forte au contact d'une lignine condensee. L'observation in situ a souligne le role du polysaccharide extracellulaire a l'interface entre paroi lignocellulosique et paroi de l'hyphe, dans le support de certaines enzymes excretees. Les marqueurs de lignines ont en outre revele la presence de fragments de degradation transitant a travers la paroi des hyphes. L'intensite des marquages avec les differents anticorps suggere que les fragments syringiques ont subi une demethylation avant d'etre metabolises dans la paroi de l'hyphe. La delignification des pates chimiomecaniques par des preparations de mnp et de lac purifiees ont montre que ces deux enzymes realisaient des defibrillations locales tres efficaces.
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Siochi, Emilie J. "Dilute solution studies of molecular weight distributions of nitrocellulose, modified lignins and PMMA graft polymers". Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54423.

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Dilute solution properties of three difficult-to-analyze macromolecular systems were investigated and clarified. Two were notorious for having highly time-in-solution dependent properties, nitrocellulose and lignin, while the third was an ideal model branched methacrylate polymer with which to examine unanswered questions in polymer hydrodynamic behavior. Gel permeation chromatography with a differential viscosity detector (GPC/DV) was employed to study the dilute solution properties of various polymers, specifically their absolute molecular weight distributions and hydrodynamic behavior. The study was divided into three parts. The first part focused on the time dependent change in molecular weight of nitrocellulose. Samples having 12.58% and 13.5% levels of nitration were investigated in THF and EtOAc. GPC/DV, LALLS, FT-IR and intrinsic viscosity experiments revealed that the materials existed as associated molecules in solution which decreased in molecular weight upon storage to extents dependent on the solvent. The second part was an examination of the hydrodynamic behavior of hydroxypropylated lignins using GPC/LALLS/DV and VPO. These materials were found to increase in molecular weight upon storage in solution due to association. Special precautions had to be taken in running experiments to obtain the correct molecular weights and molecular weight distributions. The last part involved a fundamental study of PMMA-g-PMMA's having similar molecular weights but containing different levels of branching. Variable temperature GPC/LALLS/DV was employed to obtain molecular weight distributions, branching parameters, average chain dimensions and information on the hydrodynamic behavior of these branched systems. Samples containing up to 40% of long chain branching were found to obey the universal calibration analytic scheme of GPC.
Ph. D.
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Książki na temat "Lignin distribution"

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Hydro-Québec. Division terminologie et documentation. Vocabulaire illustré des lignes souterraines de transport et de distribution d'électricité. [Montréal]: Hydro-Québec [Information, Édition et production], 1986.

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Pansini, Anthony J. Electrical distribution engineering. Wyd. 2. Lilburn, GA: Fairmont Press, 1992.

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Pansini, Anthony J. Electrical distribution engineering. Wyd. 3. Boca Raton, FL: CRC Press/Taylor & Francis, 2006.

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Directorate, Canada Drugs. Guidelines for the secure distribution of narcotic and controlled drugs in hospitals =: Lignes directrices sur la distribution sécuritaire des stupéfiants et des drogues contrôlées dans les hôpitaux. Ottawa, Ont: Health and Welfare Canada = Santé et bien-être social Canada, 1990.

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Québec (Province). Bureau d'audiences publiques sur l'environnement. Projet de ligne à 315 kV Grand-Brûlé - Vignan par Hydro-Québec. Québec]: Bureau d'audiences publiques sur l'environnement, 2001.

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Slavin, Lawrence M. Overhead Distribution Lines: Design and Applications. Wiley & Sons, Limited, John, 2020.

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Slavin, Lawrence M. Overhead Distribution Lines: Design and Applications. Wiley & Sons, Incorporated, John, 2020.

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Slavin, Lawrence M. Overhead Distribution Lines: Design and Applications. Wiley & Sons, Limited, John, 2021.

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Slavin, Lawrence M. Overhead Distribution Lines: Design and Applications. Wiley & Sons, Incorporated, John, 2020.

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Pansini, Anthony J. Electrical Distribution Engineering. Wyd. 3. Fairmont Press, 2006.

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Części książek na temat "Lignin distribution"

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Johnson, D. K., Helena Li Chum i John A. Hyatt. "Molecular Weight Distribution Studies Using Lignin Model Compounds". W ACS Symposium Series, 109–23. Washington, DC: American Chemical Society, 1989. http://dx.doi.org/10.1021/bk-1989-0397.ch008.

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Decou, Raphaël, Henrik Serk, Delphine Ménard i Edouard Pesquet. "Analysis of Lignin Composition and Distribution Using Fluorescence Laser Confocal Microspectroscopy". W Methods in Molecular Biology, 233–47. New York, NY: Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-6722-3_17.

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Froment, P., i F. Pla. "Determinations of Average Molecular Weights and Molecular Weight Distributions of Lignin". W ACS Symposium Series, 134–43. Washington, DC: American Chemical Society, 1989. http://dx.doi.org/10.1021/bk-1989-0397.ch010.

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Himmel, M. E., K. Tatsumoto, K. K. Oh, K. Grohmann, D. K. Johnson i Helena Li Chum. "Molecular Weight Distribution of Aspen Lignins Estimated by Universal Calibration". W ACS Symposium Series, 82–99. Washington, DC: American Chemical Society, 1989. http://dx.doi.org/10.1021/bk-1989-0397.ch006.

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Forss, Kaj, Raimo Kokkonen i Pehr-Erik Sågfors. "Determination of the Molar Mass Distribution of Lignins by Gel Permeation Chromatography". W ACS Symposium Series, 124–33. Washington, DC: American Chemical Society, 1989. http://dx.doi.org/10.1021/bk-1989-0397.ch009.

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Radotić, Ksenija, Dragica Spasojević i Danica Zmejkoski. "Lignin-based Materials for Biomedical Applications: Basic Requirements and Properties". W Lignin-based Materials, 85–105. The Royal Society of Chemistry, 2023. http://dx.doi.org/10.1039/bk9781839167843-00085.

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The material selected for biomedical application must be biocompatible, stable against physiological media, non-toxic, non-carcinogenic, corrosion-resistant, bio-inert, and stimuli-responsive, and have a low wear rate. Lignin is the most abundant aromatic polymer on Earth with a complex, recalcitrant structure. A lot of knowledge is acquired on its pre-treatments and processing for biomedical uses in the forms of hydrogels, films, composite materials, nanoparticles, and aerogels. To avoid the potential toxicity and to control the cytotoxicity of lignin-based materials, it is necessary to increase the purity of the starting source materials and understand their reactivity. The poor water solubility, broad molecular weight (MW) distribution, and highly complex structure of lignin restrict its wider clinical applications. These limitations may be effectively improved by chemical modifications or by using lignin fractions with a narrow MW range. Antioxidant and antimicrobial properties allow lignin to be used in pharmaceuticals, drug delivery, and wound healing. It is also reported as a good candidate for composite materials intended for bone regeneration scaffolds in tissue engineering. Future challenges for lignin-based materials for biomedical applications include achieving a better understanding of the structure, isolation, and batch properties of lignin, as well as structure–function relationships in its applications.
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Higuchi, Takayoshi. "Lignin Structure and Morphological Distribution in Plant Cell Walls". W Lignin Biodegradation: Microbiology, Chemistry, and Potential Applications, 2–19. CRC Press, 2018. http://dx.doi.org/10.1201/9781351074063-1.

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Vara, Saritha. "Mycoremediation of Lignocelluloses". W Biotechnology, 1086–108. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-8903-7.ch042.

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The most abundant aromatic biopolymer on earth Lignin is extremely recalcitrant to degradation. It creates a barrier to solutions or enzymes by linking to both hemicellulose and cellulose preventing the penetration of lignocellulolytic enzymes into the interior lignocellulosic structure. Global attention has been gained by fungi owing to the potential use of their versatile enzymes for agriculture, medicines, industries and bioremediation. The combination of extracellular ligninolytic enzymes, mediators, organic acids and accessory enzymes make some of the basidiomycete white-rot fungi to be able to degrade lignin efficiently. This review describes remediation of lignocelluloses by fungi, properties of fungi, their spatial distribution and the mechanisms of action which render them attractive candidates in biotechnological applications like biopulping, animal feed, genetic engineering and space exploration.
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Vara, Saritha. "Mycoremediation of Lignocelluloses". W Handbook of Research on Inventive Bioremediation Techniques, 264–86. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-2325-3.ch011.

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The most abundant aromatic biopolymer on earth Lignin is extremely recalcitrant to degradation. It creates a barrier to solutions or enzymes by linking to both hemicellulose and cellulose preventing the penetration of lignocellulolytic enzymes into the interior lignocellulosic structure. Global attention has been gained by fungi owing to the potential use of their versatile enzymes for agriculture, medicines, industries and bioremediation. The combination of extracellular ligninolytic enzymes, mediators, organic acids and accessory enzymes make some of the basidiomycete white-rot fungi to be able to degrade lignin efficiently. This review describes remediation of lignocelluloses by fungi, properties of fungi, their spatial distribution and the mechanisms of action which render them attractive candidates in biotechnological applications like biopulping, animal feed, genetic engineering and space exploration.
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Gurrala, Lakshmiprasad, M. Midhun Kumar i R. Vinu. "Catalytic hydrogenolysis of lignin to phenols: Effect of operating conditions on product distribution". W Biomass, Biofuels, Biochemicals, 83–107. Elsevier, 2021. http://dx.doi.org/10.1016/b978-0-12-820294-4.00001-6.

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Streszczenia konferencji na temat "Lignin distribution"

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Kovalev, I. V., i N. O. Kovaleva. "Lignin phenols content and distribution in gran-size fractions of soils". W Fifth International Conference of CIS IHSS on Humic Innovative Technologies «Humic substances and living systems». CLUB PRINT ltd., 2019. http://dx.doi.org/10.36291/hit.2019.kovalev.034.

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Maramokhin, E. V., M. V. Sirotina i A. S. Dyukova. "THE ROLE OF SUBSTRATE FACTOR IN DISTRIBUTION OF CERTAIN XYLOTROPHIC BASIDIOMYCETES IN BIRCH AND ASPEN FORESTS OF KOSTROMA REGION". W SAKHAROV READINGS 2021: ENVIRONMENTAL PROBLEMS OF THE XXI CENTURY. International Sakharov Environmental Institute, 2021. http://dx.doi.org/10.46646/sakh-2021-1-290-294.

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The distribution of xylotrophic basidiomycetes, as any other species, depends on ecological elasticity in relation to abiotic, biotic and anthropogenic environmental factors. A special role among biotic factors for these organisms is assigned to substrate specialization. The high significance of the substrate factor is distinctive for the destructor fungi, which is reflected in the special enzymatic apparatus of these organisms capable of destroying lignin and cellulose. This article comprehensively examines the impact of the substrate factor on the distribution of the studied phytopathogens in small-leaved forests of Kostroma region.This will make it possible to better understand the biology and ecology of xylotrophic basidiomycetes.
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Maramokhin, E. V., M. V. Sirotina i A. S. Dyukova. "THE ROLE OF SUBSTRATE FACTOR IN DISTRIBUTION OF CERTAIN XYLOTROPHIC BASIDIOMYCETES IN BIRCH AND ASPEN FORESTS OF KOSTROMA REGION". W SAKHAROV READINGS 2021: ENVIRONMENTAL PROBLEMS OF THE XXI CENTURY. International Sakharov Environmental Institute, 2021. http://dx.doi.org/10.46646/sakh-2021-1-290-294.

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The distribution of xylotrophic basidiomycetes, as any other species, depends on ecological elasticity in relation to abiotic, biotic and anthropogenic environmental factors. A special role among biotic factors for these organisms is assigned to substrate specialization. The high significance of the substrate factor is distinctive for the destructor fungi, which is reflected in the special enzymatic apparatus of these organisms capable of destroying lignin and cellulose. This article comprehensively examines the impact of the substrate factor on the distribution of the studied phytopathogens in small-leaved forests of Kostroma region.This will make it possible to better understand the biology and ecology of xylotrophic basidiomycetes.
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Kimura, Minoru, Satoshi Kimura, Zi-Dong Qi, Shigenori Kuga i Akira Isogai. "Porous Structure of Never-Dried Pulp Fibers Analyzed by Nitrogen Adsorption Method". W Advances in Pulp and Paper Research, Cambridge 2013, redaktor S. J. I’ Anson. Fundamental Research Committee (FRC), Manchester, 2013. http://dx.doi.org/10.15376/frc.2013.2.821.

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Porous structures of never- dried pulp fibers were investigated by nitrogen adsorption method. A distinct bent-point in the desorption isotherms was observed at a 45% relative vapor pressure for both softwood and hardwood never- dried pulp fibers. The singular reduction in nitrogen adsorption volume was likely attributed to the presence of mesopores formed via lignin removal in wood cell walls during pulping, which was indicated from the results of nitrogen adsorption/desorption isotherms for partially delignified wood powders. The specific surface area of a sufficiently delignified softwood powder was ~150 m2/g, slightly lower than 200 m2/g. These results indicate that 4×4=16 individual cellulose microfibrils (each of which is 3–4 nm wide) form one unit of cellulose fibril bundle and each bundle is surrounded by lignin thin layer in softwood cell walls. On the contrary, partially delignified hardwood powders had extremely small specific surface areas, whereas a hardwood pulp fiber showed a fairly large surface area. The specific surface areas of delignified hardwood powders were drastically increased after extraction with alkali to remove xylan. Thus, not only lignin but also xylan plays a significant role in the formation of pore structures for the hardwood pulp fiber and the delignified wood powders. The results of pore size distribution analysis using BJH and NLDFT techniques showed that the sizes of principal mesopores present in unbeaten pulp fibers were 3.2–3.7 nm and were increased by disintegration process.
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"Assessment of Formula-Based Structural Annotation of Humic Substances by Mild Chemical Derivatization and Mass Spectrometry". W Sixth International Conference on Humic Innovative Technologies "Humic Substances and Eco-Adaptive Technologies ”(HIT – 2021). Non-Commercial Partnership "Center for Biogenic Resources "Humus Sapiens" (NP CBR "Humus Sapiens"), 2021. http://dx.doi.org/10.36291/hit.2021.mikhnevich.002.

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Natural organic matter (NOM) plays an important role in the environment and its chemical properties and molecular composition reflect balance between mineralization and sequestration of organic carbon. Ultrahigh resolution mass spectrometry (e.g., FTICR MS) provides essential molecular information about NOM. However, NOM molecular heterogeneity prevents application of tandem MS experiments and direct structural information is ultimately missing leaving opportunities to only ambiguous formula-based annotation. The main aim of this work was to develop a chemical workflow to reliably examine the accuracy of several FTICR MS-derived structural indices with the focus on aromaticity and O-functional groups, which greatly impact compound properties. Four NOM samples of different origin (coal, oxidized lignin, river, and permafrost thaw) were brominated by NBS in acetonitrile for 24 hrs at RT. Carboxylic groups in all samples were determined by selective deuteromethylation using CD 3OD/SOCl2 reaction and by HATU amidation with 15N labeled glycine. Carbonyl groups were reduced by NaBD4. All parent and labeled mixtures were analyzed by ESI FTCR MS. Custom python scripts were developed to treat spectra and enumerate specific structural moieties in individual components. Obtained data was used to assess reliability of exact aromaticity indices (AI)1 and aromaticity equivalents (Xc) 2. Lignin- and coal-derived samples turned out to be the most sensitive to bromination which corroborated with the model phenolic structures. On contrary, permafrost thaw, which is enriched with labile species, was mostly resistant to bromination - 22% of molecular ions were brominated. Moreover, unlike oxidized riverine sample, coal NOM included polybrominated species, which implies that reaction efficiency depends on reactivity (i.e. substituents) of aromatic fragments. Samples were characterized by drastically different bromine distributions on van Krevelen diagrams, which correlated with the distribution of non-carboxylic oxygen atoms. Further, we compared AI and Xc aromaticity indices in terms of the proportion of correctly assigned aromatics. The data on brominated molecules were in good agreement with the AI values; however, apparently AI tends to overestimate the number of non-aromatics in the sample since it describe averaged aromaticity rather than the factual presence of aromatic ring. On the other hand, Xc perfectly recognized non-aromatics. In general, a higher proportion of correctly attributed aromatics was observed for the aromaticity equivalent Xc (up to 68%), which tends to find aromatic moieties in non-aromatic molecules assigned by AI. Still, we observed a number of aromatic- and condensed aromatic-assigned compounds, which were resistant to bromination or included lesser Br-atoms than the evaluated number of aromatic rings. Reaction with NaBD4 and enumeration of labeling series revealed the presence of carbonyl groups in these species, which in case of multiple reducing could be reliably assigned to quinone – condensed non-aromatic compounds. The approach may be of great importance in biogeochemical and medicinal studies of NOM. Acknowledgements. This work was supported by the Russian Science Foundation gran No 21-47-04405. References 1. Zherebker, A., Lechtenfeld, O. J., Sarycheva, A., Kostyukevich, Y., Kharybin, O., Fedoros, E. I. and Nikolaev, E. N. Anal. Chem., 2020, 92 (13), 9032-9038; 2. Yassine, M.M., Harir, M., Dabek-Zlotorzynska, E. and Schmitt-Kopplin, P. Rapid Commun. Mass Spectrom., 2014, 28, 2445-2454.
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Lindström, Tom, Lars Wågberg i Tomas Larsson. "Review: On the Nature of Joint Strength in Paper – A Review of Dry and Wet Strength Resins Used in Paper Manufacturing". W Advances in Paper Science and Technology, redaktor S. J. I’Anson. Fundamental Research Committee (FRC), Manchester, 2005. http://dx.doi.org/10.15376/frc.2005.1.457.

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The properties of paper are largely dependent on the bonds between the fibres. This is, of course, primarily true of those strength properties that are directly related to the number of bonds in the paper. Other properties are also dependent on such bonds, properties such as the opacity of the paper, its smoothness, porosity, dimensional stability, pore size distribution, linting propensity, density, stiffness, formation, and compressibility to mention a few. The normal way of affecting the number of bonds in a paper is through the choice of fibre material and through a correct beating of the pulp. It is true that properties of paper may be manipulated through the choice of beater type, its specific edge load etc to expand the property or process space in paper manufacture. There are still many limitations as to what can be achieved by beating and other process tools, so the practical paper-maker is continuously looking for ways to expand property and process space to be able to manufacture new products or boost paper machine productivity. In this review the terms “bonding” and “joint strength” will be used interchangeably. “Joint strength” includes both the adhesion zone (2D zone of bonding) and the cohesion zone (3D zone of bonding). Despite massive efforts over the years, our understanding of the molecular mechanisms of bonding is still in its infancy. There is still the fundamental argument as to the relative contribution of hydrogen bonds, ionic bonds, dipolar interactions, induced polar interactions, long-range van der Waals forces, and covalent forces (for wet strength resins) in various situations. Taken to the extreme, it was once believed that lignin contributed little to bonding in lignin-rich pulps, because they were assumed to be poor hydrogen bonding agents. Not anymore, as it has been realised that strong bonding can be created between mechanically liberated pulp fibres. Though critical experiments still need to be formulated to examine such matters, this review will not focus on them. It is acknowledged, that hydrogen bond theories have been formulated by Corte and Shashek (1955), Nissan and Sternstein (1964) and others, but it has not been possible to further expand our knowledge from the initial formulations. This review will instead focus on the use of various dry and wet strength additives to improve bond strength. The authors have made efforts to relate the discussion to the historical and current context of dry and wet strength resins, and to discuss more recent developments in understanding adhesive and cohesive failure. Hence, after some general considerations and introduction to the concepts of process and property space in paper manufacture, a brief discussion of current paper strength theories will be made. A more detailed account of adhesive and cohesive failure mechanisms will follow, after which dry and wet strength resins will be reviewed. As far as wet strength agents are concerned, traditional wet strengthening will be given less emphasis; the focus of this later part will instead be on potential chemistries to alleviate tensile creep and compression creep under moist conditions.
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Batista, Gabriel F., i Paulo Brito. "RESIDUAL BIOMASS CHARACTERIZATION AND EVALUATION OF ITS INFLUENCE ON PYROLYSIS PROCESSES". W 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022v/4.2/s17.72.

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Biomass is extensively accepted as one of the main potential sources for sustainable and renewable generation of fuels, chemicals and other carbon-based materials. Many advantages are reported using biomass as an energy source, such as being a non-polluting alternative and its carbon neutrality. Numerous processes can be used to convert biomass, and namely the pyrolysis process is a renewable, economical, and efficient way to produce chemicals and/or energy. Therefore, pyrolysis is an available technology for biomass conversion into energy. It consists of a thermal decomposition process with the absence of oxygen, converting biomass into 3 fractions: biochar (solid fraction), bio-oil (liquid fraction) and gases. Hence, pyrolysis is a recognized industrial process for biomass energy and chemical conversion. The bio-oil and biochar can be used as a fuel and as fertilizer respectively, and the gases can be recycled back into the process. Biomass samples were characterized by proximate analysis, determining fixed carbon, moisture, volatiles and ashes composition, and by ultimate analyses, determining the content of C, H, N, S and O. The content of hemicellulose, lignin and cellulose was also determined. The methodologies are described elsewhere and all characterizations were performed on a dry basis. Pyrolysis tests were performed in a fixed-bed vertical pyrolysis oven, with a maximum temperature of 500 to 700 ?C, variable heating rate up to 50 ?C/min, retention time of 0.5 h, and N2 flow of 20 mL/min. The bio-oil and biochar were qualitatively characterized using FTIR and the products distribution was analyzed in relation to the biomass samples previous characterization.
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Zhang, Chunhui, Xuwen He, Shuquan Zhu, Xiaochan Wang i Honglei Zhuang. "Distribution, Character and Utilization of Lignite in China". W 2011 Asia-Pacific Power and Energy Engineering Conference (APPEEC). IEEE, 2011. http://dx.doi.org/10.1109/appeec.2011.5748423.

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Fu, Bi An, Meiqian Chen i Q. H. Li. "LNT microwave-multiphase transport model for the microwave drying of lignite thin layer". W 21st International Drying Symposium. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/ids2018.2018.7683.

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The LNT microwave-multiphase transport model has been applied to the microwave drying of lignite thin layer. Microwave energy, temperature and moisture distribution were obtained to gain a comprehensive understanding on the heat and mass transfer mechanism of the drying process. The required drying time of experiments decreased by 50, 63, 67, and 83%, respectively, with the power level rising from 119 to 700 W, while that decreased by 60, 72, 76 and 86%, respectively, for simulation results. The temperature values of the corner and edge of the lignite thin layer were higher than that of the center region, which corresponded to the microwave energy distribution. The moisture ratio profiles, temperature profiles and temperature distribution indicated good agreement between the experimental and simulation results, providing confidence in the modeling approach, which made it possible to obtain the moisture distribution successfully via simulation method.Keywords: microwave; lignite; thin layer.
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Konstantinova, D. A., V. P. Gorbatenko i T. V. Ershova. "Spatial distribution of ligtning discharges density on Western Siberia". W 2010 30th International Conference on Lightning Protection (ICLP). IEEE, 2010. http://dx.doi.org/10.1109/iclp.2010.7845826.

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Raporty organizacyjne na temat "Lignin distribution"

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Ardakani, O. H. Organic petrography and thermal maturity of the Paskapoo Formation in the Fox Creek area, west-central Alberta. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/330296.

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The Paskapoo Formation, which ranges in age from middle to upper Paleocene, is the major shallow aquifer in Alberta. This study is part of a larger GSC-led study on the potential environmental impact of hydrocarbon development in the Fox Creek area (west-central Alberta) on shallow aquifers. Fox Creek is located near the northern limit of the Paskapoo Formation. In addition to the underlying organic-rich source rocks in the study area, including the Duvernay Formation that is currently exploited for hydrocarbon resources, the Paskapoo Formation contains organic-rich intervals and coal seams. In order to investigate any potential internal hydrocarbon sources within the Paskapoo Formation, ninety-seven (97) cutting samples from the formation obtained from eight shallow monitoring wells (50-90 m) in the study area were studied for total organic carbon (TOC) content, organic matter composition and thermal maturity of coal seams using programmed pyrolysis analysis and organic petrography. The TOC content of all samples ranges from 0.2 to 8.8 wt. %, with a mean value of 0.95 ± 1.6 wt. % (n=97). The Tmax values of studied samples range from 347 to 463 °C, with a mean value of 434 ± 20 °C that suggest a range of thermal maturity from immature to peak oil window. The random reflectance (Rr) measurement and fluorescence microscopy on eighteen (18) selected samples with TOC content > ~1 wt. % shows a mean Rr value of 0.27% and 0.42% for the overlying till deposits and the underlying shallow depth sandstone, siltstone, shale and coal seams respectively, indicating a low rank coal ranging from lignite to sub-bituminous coal. Blue to green and yellow fluorescing liptinite macerals further confirmed the low maturity of studied samples. The low S2 yield of a large part of the samples (65%) resulted in unreliable Tmax values that overestimated the thermal maturity. Although the organic matter in the studied intervals are immature, exsudatinite, as secondary liptinite maceral, was observed in samples from the lower parts of the studied monitoring wells. Exsudatinite generally derives from the transformation of sporinite, alginite, resinite and varieties of vitrinite, which is a resinous or asphalt like material. Considering the thickness and distribution of coal seams in the studied samples, it is unlikely the exsudatinite will be a major source for aquifer hydrocarbon contamination in the study area. Additional stratigraphic studies and molecular geochemical analysis could provide an estimate of the total volume of possible organic compounds contribution to the aquifer in the study area. Due to the presence of coal seams in the studied intervals of the Paskapoo Formation, it is important to investigate the possibility of biogenic methane formation in Paskapoo shallow aquifers.
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