Academic literature on the topic 'Destruction of cellulose'
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Journal articles on the topic "Destruction of cellulose"
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Kholodkova, E. M., A. V. Bludenko, V. N. Chulkov, and A. V. Ponomarev. "Cellulose destruction by electron-beam-induced heating." Russian Chemical Bulletin 59, no. 9 (September 2010): 1827–33. http://dx.doi.org/10.1007/s11172-010-0319-5.
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Vaniushenkova, Anna A., Elina E. Dosadina, Anna A. Hanafina, Sergey V. Kalenov, Nikolay S. Markvichev, and Alexey A. Belov. "Synthesis and study of the properties of composite materials based on cellulose and chitosan containing various therapeutic agents. Part 3. Hydrolytic destruction of dressings based on dialdehydecellulose." Butlerov Communications 59, no. 8 (August 31, 2019): 47–59. http://dx.doi.org/10.37952/roi-jbc-01/19-59-8-47.
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Creating systems for targeted delivery of drugs to the affected organ is one of the most promising areas for the development of systems with controlled release of the active substance. Polysaccharides are widely used as drug carriers. However, most of them are chemically inert and require preliminary functionalization in order to interact with physiologically active compounds (therapeutic agents-TA). A simple and effective method for introducing reactive groups is the periodic oxidation of the polysaccharide by the Malaprade reaction. While cellulose is insoluble in water and resistant to weak solutions of acids and alkalis, dialdehyde cellulose (DAC is the product of the periodic oxidation of cellulose) and its derivatives are destroyed in water and weakly acidic and slightly alkaline solutions. This process is called hydrolytic destruction. The kinetics of hydrolytic destruction is described by semi-logarithmic anamorphosis, which allows us to calculate the rate constants of hydrolytic destruction as the rate constant of first-order reactions. The products of hydrolytic degradation were studied by UV spectroscopy and using 3,5-dinitrosalicylic acid (DNSA). The degradation products of C and DAC were also studied by the phenol-sulfur method. From the data presented and cited earlier, it follows that when our composite material is placed in a liquid medium, the hydrolytic destruction of the drug immediately begins. What can be connected with the breakdown of both the carrier – TA bonds (DAC, C, Ct carriers) and the destruction of the carrier itself. Under the conditions of the organism, biological destruction can also join process. Biodestruction is the process of destruction (both carriers and immobilized TAs) under the action of the body's enzymes. Using IR spectroscopy, cellulose carriers were studied before and after exposure to 1/15M FB medium (pH 6.2 and 37 °C) for 48 hours. As can be seen from the data obtained, primarily for DAC samples, significant changes in the spectrum are visible in the 1800-1600 and 900 cm-1 fields. The results of experimental toxicological studies of samples of various cellulosic materials allow us to conclude that the samples studied do not have toxic, hemolytic, allergenic effects, as well as mutagenic activity.
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Gupta, Ashwani K. "Thermal Destruction of Cellulose and Surrogate Solid Wastes." Journal of Propulsion and Power 16, no. 4 (July 2000): 615–22. http://dx.doi.org/10.2514/2.5617.
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Dubyago, Marina N., Irina A. Poluyanovich, and Nikolay K. Poluyanovich. "Thermodynamic Approach for Identifying Oxidative Processes Insulation Breakdown." Applied Mechanics and Materials 752-753 (April 2015): 1153–57. http://dx.doi.org/10.4028/www.scientific.net/amm.752-753.1153.
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Problematic issues insulation of power cable systems (PCS) based on the design and development of non-destructive methods are considered in the paper. The basic components of the PCS, destroying the insulation, are determined. The analytical method for assessing the oxidation processes of cellulose with the definition of the most probable is proposed. The approach for identifying the main processes of destruction of the insulation allows more detail to present background to the development of partial discharges (PD) in insulation and to identify measures for minimizing processes that lead to the destruction of the insulation PCS.
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Doncea, Sanda Maria. "FTIR Analysis Both for Degradation and Treatment with Nanoparticles of Historical Paper." Proceedings 29, no. 1 (October 16, 2019): 88. http://dx.doi.org/10.3390/proceedings2019029088.
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Мамлеева (Mamleeva), Надежда (Nadezhda) Алексеевна (Alekseevna), Андрей (Andrey) Николаевич (Nikolaevich) Харланов (Kharlanov), Дмитрий (Dmitriy) Германович (Germanovich) Чухчин (Chukhchin), Наталья (Natal'ya) Григорьевна (Grigor'evna) Базарнова (Bazarnova), and Валерий (Valeriy) Васильевич (Vasil'evich) Лунин (Lunin). "DEGRADATION OF PINE WOOD STRUCTURE WHEN OZONOLYTIC DELIGNIFICATION." chemistry of plant raw material, no. 1 (March 6, 2019): 85–94. http://dx.doi.org/10.14258/jcprm.2019015143.
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The pine wood degradation under ozonation was studied. It was determined the contents of lignin (LG) and cellulose (CL) in cellulose-containing material (CM) obtained from the ozonized wood. The degree of polymerization (DP) of cellulose from CM was determined. Samples of CM were investigated using IR diffuse reflectance (DRIFT) spectra and XRD analysis. HPLC analysis of water-soluble LG ozonolysis products was conducted.
Ozonation results in 40–42% delignification degree of wood. Aromatics destruction is confirmed by DRIFT spectra. The intensity of stretching band at 1736 cm-1 of unconjugated C=O groups in LG or hemicelluloses markedly increases.
A stoichiometric ratio of absorbed ozone and an amount of destructed guaiacylpropane units as well as a composition of water-soluble products show that ozonolysis is a primary mechanism of aromatics degradation in wood.
The data on XRD analysis, the amounts of removed LG and the change of cellulose DP allow conclusion that the wood ozonation is accompanied by a destruction of hemicelluloses and amorphous cellulose in the wood.
It is shown that the specific ozone uptake £1.5 mmol O3/g matches the domination of the wood delignification with the lowest degradation of cellulose fibers and acceptable efficiency in terms of the ozonation process.
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Osovskaya, Iraida Ivanovna, and Veronika Sergeyevna Antonova. "THE INFLUENCE OF SURFACE DESTRUCTION ON THE HYDROPHILICITY AND ABILITY TO FORM CONNEC-TIONS OF THE CELLULOSE FIBERS." chemistry of plant raw material, no. 1 (March 5, 2020): 315–20. http://dx.doi.org/10.14258/jcprm.2020016269.
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When using cellulose fibers to produce paper, the main role is played by the state of the surface of the fiber and its ability to adhesive-cohesive interaction. The main indicators characterizing the surface of the fiber are development and roughness, chemical heterogeneity, depending on the presence of various functional groups, as well as structural heterogeneity of the surface layers, leading to the formation of a stronger bond between the fibers. The surface modification of the fiber was carried out by partial acid hydrolysis. The study is aimed at optimizing hydrolysis, choosing methods for its control, obtaining physicochemical and physicomechanical characteristics of partially hydrolyzed cellulose, and increasing the ability to bind cellulose fiber. A method has been developed for producing modified cellulose with improved adhesion-cohesive properties by surface destruction of wet cellulose fibers during hydrolysis. The patterns of activation of the surface properties of cellulose fibers are obtained. The effect of partial acid hydrolysis on the development of the surface of the fiber in the absence of "wet" grinding with water shortage is shown. The effect of short chains and reducing carbonyl groups of cellulose macromolecules on the binding capacity of modified cellulose has been established. The optimal content of short chains of cellulose macromolecules, which is 12%. Such a content of short chains of modified fibers by acid hydrolysis was detected at a temperature of 363 K and an exposure time of 40 s; under these optimal conditions, the strength of the experimental castings increases by 70%.
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Manucharova, N. A. "The microbial destruction of chitin, pectin, and cellulose in soils." Eurasian Soil Science 42, no. 13 (December 2009): 1526–32. http://dx.doi.org/10.1134/s1064229309130146.
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Badretdinova, I. V., Ye A. Vorontsova, V. V. Kasatkin, and A. B. Spiridonov. "BIOLOGICAL METHODS OF DESTRUCTION OF THE FLAX FIBER CELLULOSE COMPLEX." Bulletin of Izhevsk State Agricultural Academy, no. 1 (2021): 33–38. http://dx.doi.org/10.48012/1817-5457_2021_1_33.
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Stepina, Irina Vasilevna. "Change in Crystalline Structure of Cellulose Caused by Wood Preservation." Materials Science Forum 923 (May 2018): 51–55. http://dx.doi.org/10.4028/www.scientific.net/msf.923.51.
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Сhemical interaction of cellulose with reactive groups of four-coordinate boron-nitrogen compounds is an intercrystalline process proceeding without destruction of cellulose crystalline structure; probably, the modifier molecules react with easier accessible hydroxyl groups of the amorphous cellulose regions. The formation of B-O-C ether bonds between OH groups of modifiers and more reactive hydroxyl groups of amorphous parts of cellulose results in redistribution of hydrogen bonds and, as a consequence, to rectification of cellulose macromolecules. Thus, when cellulose is treated with compositions based on four-coordinate boron-nitrogen compounds, crystalline structure of cellulose is not disrupted, hence this process can be called a "mild" modification. Such modification does not lead to accelerated aging of cellulose materials, rapid loss of strength and increases durability of wooden structures.
Dissertations / Theses on the topic "Destruction of cellulose"
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Драпой, Дарина Ігорівна. "Одержання водню з целюлозовмісної сировини." Doctoral thesis, Київ, 2021. https://ela.kpi.ua/handle/123456789/43553.
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Дисертація присвячена науково-технічним основам технології ферментації сільськогосподарських відходів з отриманням водню.
В дисертаційній роботі було виділено ефективну асоціацію мікроорганізмів-деструкторів целюлози та продуцентів водню. За основу взято природну асоціацію мікроорганізмів з ґрунту, що зменшує вміст в асоціації консументів водню – сульфатредукуючих мікроорганізмів, в порівнянні з природними асоціаціями з мулу та проточних водойм.
В роботі експериментально визначено, що для знешкодження метаноутворюючих мікроорганізмів необхідно проводити температурну обробку інокуляту при t = 90ºС протягом 1 години. За даної обробки мікроорганізми родів Clostridium та Bacillus утворюють спори, що проростають вже за 2 дні за сприятливих умов.
Визначено, що додаткове збагачення асоціації мікроорганізмами родів Clostridiuт та Bacillus призводить до збільшення виходу водню в порівнянні з вихідною асоціацією. При чому вміст водню в біогазі залежить від кількості та співвідношення мікроорганізмів, що додаються. Встановлено, що збагачення асоціації культурами мікроорганізмів родів Clostridium та Bacillus у співвідношенні 1:2,5 дає можливість збільшити вихід водню в 2,3 рази.
Визначено раціональний метод попередньої обробки сировини (3 год, 20% NaOH) що дозволяє підвищити вихід водню у 3 рази. Луг ефективно видаляє лігнін з біомаси, покращує доступність целюлози та збільшує площу адсорбція субстрату для мікроорганізмів.
В дисертаційній роботі наведено математичний опис продукування біогазу залежно від значення рН та концентрації субстрату, що дозволяє моделювати довільний характер процесу і визначати оптимальні умови продукування водню в залежності від змінних параметрів процесу.
Визначено основні технологічні параметри процесу ферментації целюлозовмісної сировини з продукуванням водню: температура процесу – 35ºC, рН - 7 – 7,5, концентрація сировини - 50 ± 5 г/дм3, співвідношення інокуляту до субстрату 1:4, постійне відведення водню з зони ферментації, що дозволяє одержати біогаз з вмістом водню 87,5±4,2%.
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Thivolet, Charles. "Étude des marqueurs de la destruction autoimmunitaire des cellules béta pancréatiques : application au dépistage du diabète insulinodépendant." Lyon 1, 1989. http://www.theses.fr/1989LYO1H086.
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Schneider, Fabrice. "Remodelage de la paroi artérielle : étude des aspects de destruction et de reconstruction." Thesis, Paris Est, 2011. http://www.theses.fr/2011PEST0101/document.
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L’athérosclérose et la pathologie anévrysmale sont principalement caractérisées par un remodelage de laparoi artérielle au cours de leur évolution. Ce travail a examiné un aspect de la destruction de la paroiartérielle à travers l’étude de la métalloprotéase MMP-14 au cours de l’athérome et un aspect dereconstruction artérielle à travers l’étude d’une thérapie cellulaire d’un modèle d’Anévrysme de l’AorteAbdominale (AAA) par Cellules Souches Mésenchymateuses (CSMs).En utilisant un modèle de greffe de Moëlle Osseuse (MO) dans des souris Ldlr-/-, nous avons montré que ladélétion d’expression de MMP-14 dans les cellules issues de la MO provoquait une accumulation decollagène interstitiel dans la plaque athéromateuse sans modification de la composition cellulaire nivariation de taille. Une mesure de l’activité collagénolytique par substrat fluorescent a confirmé que ladélétion en MMP-14 chez les macrophages provoquait une baisse de l’activité collagénolytique. Cetteactivité est indépendante de l’activité MMP-2 et MMP-8 et pourrait être médiée partiellement parl’activation de MMP-13. Nous avons mis en évidence la présence de CSMs à la surface luminale de thrombus de AAA et nous avonsmontré une diminution significative des CSMs circulantes chez des patients porteurs de AAA. Nous avonspu stabiliser la croissance de AAA expérimentaux chez le rat à partir de xénogreffe artérielle par perfusionendoluminale de CSMs. La perfusion de CSMs provoquait une diminution de l’inflammation à court termeet favorisait la reconstruction artérielle par accumulation de collagène et d’élastine à moyen terme.En conclusion, l’activité collagénolytique de MMP-14 est un des mécanismes moléculaires possibles del’évolution de la plaque athéromateuse par rupture de plaque. Elle ouvre la perspective d’une nouvelleapproche thérapeutique et pourrait être une cible comme substrat pour une imagerie fonctionnelle de laplaque athéromateuse. L’évolution de la maladie anévrysmale pourrait être secondaire à une altération dessystèmes de réparation tissulaire dont les CSMs seraient des acteurs clé. La perfusion endoluminale desCSMs dans un modèle expérimental a permis la restauration de ces systèmes de réparation tissulaire etouvre la perspective d’un nouvel outil thérapeutique contre les AAAPas de résumé anglais
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Schneider, Fabrice, and Fabrice Schneider. "Remodelage de la paroi artérielle : étude des aspects de destruction et de reconstruction." Phd thesis, Université Paris-Est, 2011. http://tel.archives-ouvertes.fr/tel-00734365.
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L'athérosclérose et la pathologie anévrysmale sont principalement caractérisées par un remodelage de laparoi artérielle au cours de leur évolution. Ce travail a examiné un aspect de la destruction de la paroiartérielle à travers l'étude de la métalloprotéase MMP-14 au cours de l'athérome et un aspect dereconstruction artérielle à travers l'étude d'une thérapie cellulaire d'un modèle d'Anévrysme de l'AorteAbdominale (AAA) par Cellules Souches Mésenchymateuses (CSMs).En utilisant un modèle de greffe de Moëlle Osseuse (MO) dans des souris Ldlr-/-, nous avons montré que ladélétion d'expression de MMP-14 dans les cellules issues de la MO provoquait une accumulation decollagène interstitiel dans la plaque athéromateuse sans modification de la composition cellulaire nivariation de taille. Une mesure de l'activité collagénolytique par substrat fluorescent a confirmé que ladélétion en MMP-14 chez les macrophages provoquait une baisse de l'activité collagénolytique. Cetteactivité est indépendante de l'activité MMP-2 et MMP-8 et pourrait être médiée partiellement parl'activation de MMP-13. Nous avons mis en évidence la présence de CSMs à la surface luminale de thrombus de AAA et nous avonsmontré une diminution significative des CSMs circulantes chez des patients porteurs de AAA. Nous avonspu stabiliser la croissance de AAA expérimentaux chez le rat à partir de xénogreffe artérielle par perfusionendoluminale de CSMs. La perfusion de CSMs provoquait une diminution de l'inflammation à court termeet favorisait la reconstruction artérielle par accumulation de collagène et d'élastine à moyen terme.En conclusion, l'activité collagénolytique de MMP-14 est un des mécanismes moléculaires possibles del'évolution de la plaque athéromateuse par rupture de plaque. Elle ouvre la perspective d'une nouvelleapproche thérapeutique et pourrait être une cible comme substrat pour une imagerie fonctionnelle de laplaque athéromateuse. L'évolution de la maladie anévrysmale pourrait être secondaire à une altération dessystèmes de réparation tissulaire dont les CSMs seraient des acteurs clé. La perfusion endoluminale desCSMs dans un modèle expérimental a permis la restauration de ces systèmes de réparation tissulaire etouvre la perspective d'un nouvel outil thérapeutique contre les AAA
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Walter, Ulrich Josef. "On the molecular mechanisms of β cell destruction in autoimmune diabetes : a single cell approach." Paris 5, 2001. http://www.theses.fr/2001PA05N033.
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Saljén, Lisa. "Acoustic Characterization of the Frequency-Dependent Attenuation Profile of Cellulose Stabilized Perfluorocarbon Droplets." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-276836.
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The use of ultrasound contrast agents increases the information available for reconstruction during ultrasound imaging. Previously studied microbubbles, consisting of a gas core, are subject to limitations such as a short lifetime and a large size. Droplets with a liquid perfluorocarbon core that is stabilized by cellulose nanofibers eliminate these drawbacks, but require further investigation. By studying the frequency-dependent attenuation profile of the cellulose nanofiber coated perfluorocarbon droplets within an ultrasound field, information about the droplets as oscillators can be retrieved, enabling characterization of their physical properties. In this study, the frequency-dependent attenuation profile was experimentally acquired and compared between two concentrations, using flat transducers covering the frequency range of 1-15 MHz. The data collected in the time domain was processed and transformed into the frequency domain and the attenuation was calculated across the entire frequency range. Among the frequencies studied, the attenuation increases with frequency and covers the range of approximately 0.25-8.3 dB/cm and 0.01-3.3 dB/cm at the concentrations of 50 million droplets/ml and 10 million droplets/ml respectively. The attenuation reaches a minimum at 3 MHz within the highest concentration, compared to 4.43 MHz within the lowest. The increase of the attenuation with frequency is explained by the droplets not exhibiting large oscillations within the range covered. It is probable that the droplets do exhibit oscillations, due to a viscosity lower than that of water, but a resonance frequency is not found within the spectrum studied. This could be explained by a shell elasticity or a small droplet radius placing the resonance frequency outside of the spectrum studied, or high levels of damping broadening the resonance peak. Localizing the resonance frequency would enable characterization of these physical properties of the cellulose nanofiber shell as well as the perfluorocarbon liquid core of the droplets. The increase of the attenuation with frequency demonstrates that the droplets do not produce a maximized amount of scattering at a specific frequency within the range studied, which is observed among other oscillating particles implemented as ultrasound contrast agents. The attenuation is, however, larger than that of blood across all frequencies except for those among which the attenuation reaches its minimum. Potential errors that are affecting the results include droplet vaporization, the formation of flocs after the mechanical agitation has ceased, the experimental setup, the settings on the pulse generator, the sensitivity of the transducers and the processing code.
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Lindroth, Emma. "Acoustic Characterization of the Cellulose-coated Perfluorocarbon Droplets based on Phase Velocity Measurements." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-276837.
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Today, microbubbles are one of the most commonly used ultrasound contrast agents, since their high compressibility results in a strongly scattered signal. Despite this advantage, microbubbles experience limitations by the decreased stability and large diameter. The cellulose nanofiber (CNF) stabilized perfluoropentane (PFC5) droplets have the possibility of eliminating these drawbacks. In order to examine the droplet behavior and scattering ability when exposed to ultrasound, the acoustic response of the droplets is studied and compared with that of microbubbles (MBs). Therefore, this thesis aims to design an experimental set-up and a processing method to determine the phase velocity, bulk modulus and compressibility of the CNF-coated PFC5 droplets. The experimental study of the acoustic characterization uses pulse-echo spectroscopy with an aluminum reflector and seven flat transducers covering the frequency range 0.7 to 14.1 MHz. By using fast Fourier transform, while accounting for the 2πn ambiguity, the phase velocity profiles are obtained. The dispersions within this frequency spectrum are 1391-1487 m/s and 1387-1488 m/s for the concentrations 10 ∙ 106 and 50 ∙ 106 droplets/ml, respectively. These profiles display an increasing phase velocity with frequency and a slight increase in dispersion with concentration. These results agree with theory and studies examining the phase velocity of MBs. The bulk modulus presents values between 3-4 GPa, while the compressibility is 2.7 − 3.2 ∙ 10-10 𝑃𝑎-1 within the frequency range studied. Compared to water and certain MBs, both possessing a lower bulk modulus, the droplets are less compressible. To conclude, the droplets have similar phase velocity profiles with the same dependencies on frequency and concentration as MBs, resulting in similar behavior of these droplets when exposed to ultrasound. Hence, affecting the wave similarly to MBs in terms of spreading. The droplet are, however, not as compressible. This most likely affects their oscillation and they, hence, might not have equally beneficial scattering ability. This could reduce their utilization as contrast agents. Some of the potential error sources present during the laboratory work and the development of the post-processing code were not achieving perfect optimization of the transducer alignment, vaporization of the droplets resulting in reduced concentration, possible diffraction, not optimal processing of data and inadequate correction for 2πn ambiguity.
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Taylor, castillo An Young. "Nanoparticules à base de poly(L-glutamate de γ-benzyle) pour l’interception et la destruction des cellules tumorales circulantes dans la circulation sanguine." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS245.
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En dépit de progrès considérables, le cancer reste l'une des principales causes de morbidité et de mortalité dans le monde. Actuellement, 90% des décès liés au cancer sont causés par la propagation de cellules cancéreuses vers des organes distants. Une fois implantées et disséminées, les métastases sont beaucoup plus difficiles à détruire par les moyens de la chimiothérapie.A la suite d’un processus d’intravasation, certaines cellules tumorales s’échappent de la tumeur primaire et empruntent les systèmes circulatoires avant d’être ensuite extravasées, puis distribuées et finalement disséminées dans divers organes. Ainsi, dans l’environnement circulatoire, ces cellules tumorales circulantes (CTCs) se trouvent particulièrement accessibles aux agents thérapeutiques. Dans ce cadre, nous avons imaginé d’utiliser des nanoparticules à architecture contrôlée, afin d’intercepter de manière sélective ces cellules dans l’environnement sanguin.Dans cet objectif, nous avons synthétisé par ouverture de cycle de la lactone correspondante des copolymères amphiphiles di- et tri-blocs du poly(glutamate de benzyle). Leur auto-assemblage a permis d'obtenir des nanoparticules amphiphiles de taille inférieure à 100 nm et de potentiel ζ négatif, dont la géométrie contrôlable va de la forme sphérique (rapport d'aspect 1.3) à la forme ellipsoïdale (oblats) (rapport d'aspect 2,6) et qui présentant en surface des chaînes de PEG sous des conformations et des densités de surface contrôlées.En raison de leur capacité de circuler dans le compartiment sanguin, ces nanoparticules ont une probabilité d’interaction optimale avec les CTCs.L’impact de la modification de leur architecture a été établi en étudiant les capacités d’interactions des différentes nanoparticules préparées, d’une part avec les protéines plasmatiques et d’autre part, avec les différents types cellulaires rencontrés dans le compartiment sanguin.Les résultats les plus marquants montrent que l’élongation des nanoparticules (oblats) et l’anisotropie de leur surface, caractérisée par leur balance hydrophile/lipophile, gouvernent profondément leurs interactions. De manière fort intéressante, il apparaît que l’élongation des particules dont la surface est uniformément hydrophile diminue l’intensité de leur capture par les différents types cellulaires modèles étudiés (HUVECs modèle de cellules endothéliales), cellules RAW 276.7 (modèle de macrophages) et cellules PC3 (cancer de la prostate) et B16 (mélanome). En revanche, lorsque ces nanoparticules présentent une anisotropie de surface, leur capture par ces différents types cellulaires est augmentée avec l’élongation des particules (facteur d’élongation de 2,1).Dans un dernier volet expérimental, ces nanoparticules ont été modifiées par greffage de la protéine MART1 à leur surface. Ces immuno-nanoparticules ont montré une certaine capacité de reconnaissance des cellules B16 (modèle du mélanome). Leur efficacité après injection intraveineuse devra toutefois être précisée in vivoDespite the considerable progress, cancer remains one of the leading causes of morbidity and mortality worldwide. Currently, 90% of cancer deaths are caused by the spread of cancer cells to distant organs. Once implanted and disseminated, metastases are much more difficult to destroy by means of chemotherapy.Following a process of intravasation, some tumor cells escape from the primary tumor and migrate through the circulatory systems before being extravasated, then distributed and finally disseminated in various organs. Thus, in the circulatory environment, these circulating tumor cells (CTCs) are particularly accessible to therapeutic agents. In this context, we have imagined the use of nanoparticles with controlled architecture, in order to selectively intercept these cells in the blood environment.For this purpose, we have synthesized by ring opening of the corresponding lactone, amphiphilic di- and tri-block copolymers of poly (benzyl glutamate). Their self-assembly made it possible to obtain amphiphilic nanoparticles smaller than 100 nm in size and with a negative ζ potential, whose controllable geometry ranges from spherical (aspect ratio 1.3) to ellipsoidal (oblates) (aspect ratio 2, 6) and having PEG chains on the surface under controlled surface conformations and densities.Due to their ability to circulate in the blood compartment, these nanoparticles have an optimal probability of interaction with CTCs.The modification impact of their architecture has been established by studying the interaction capacities of the different nanoparticles prepared. On the one hand with the plasma proteins and on the other hand, with the different cell types encountered in the blood compartment.The most striking results show that the elongation of the nanoparticles (oblates) and the anisotropy of their surface, characterized by their hydrophilic / lipophilic balance, strongly govern their interactions. Interestingly, it appears that the elongation of particles whose surface is uniformly hydrophilic decreases the intensity of their capture by the different types of cell models studied (HUVEC model endothelial cells), RAW 276.7 cells (macrophage model) and cells PC3 (prostate cancer) and B16 (melanoma). Although, when these nanoparticles exhibit surface anisotropy, their capture by these different cell types is increased with the elongation of the particles (elongation factor of 2.1).In a final experimental part, these nanoparticles were modified by grafting the MART1 protein on their surface. These immuno-nanoparticles showed a certain recognition capacity of B16 cells (melanoma model). However, their efficacy after intravenous injection should be specified in vivo
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Leulmi-Pichot, Selma. "Destruction de cellules cancéreuses par vibrations magnéto-mécaniques de micro/nano particules magnétiques : Elaboration des particules par approche top-down, biofonctionnalisation et tests in-vitro." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENY063/document.
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Dans les prochaines années, les traitements des maladies graves (cancer, pathologies du cerveau, etc) pourraient fortement bénéficier des progrès en science des matériaux et des nanotechnologies. Du point de vue médical, il est bien connu que les cellules cancéreuses ont tendance à développer des résistances aux chimiothérapies dont les effets secondaires limitent considérablement l'efficacité des traitements. Pour ces raisons, la recherche de thérapies alternatives ciblant les cellules cancéreuses sans affecter les tissus sains est actuellement l'un des domaines les plus actifs de recherche sur le cancer. Dans ce contexte, les nanoparticules magnétiques reçoivent un intérêt croissant pour diverses applications biomédicales allant du diagnostic au traitement ciblé. En effet, grâce à leur possibilité d'actionnement contrôlé à distance par des champs magnétiques externes, les particules magnétiques ont la capacité d'exercer des forces ou couples localisés sur des espèces biologiques ciblées.Ce travail de thèse décrit une approche basée sur l'action mécanique de particules magnétiques bio-fonctionnalisées sur des cellules cancéreuses. Lorsque ces particules sont liées aux cellules cancéreuses, l'application d'un champ magnétique alternatif externe induit l'oscillation des particules, qui transmet alors une force mécanique aux cellules cancéreuses.Les particules magnétiques utilisées pour cette application ont fait l'objet d'un long développement. Contrairement aux particules magnétiques conventionnelles synthétisées par des voies chimiques (« bottom-up »), les particules étudiées dans cette thèse ont été spécialement conçues par des techniques développées pour la micro/nanoélectronique (« top-down »). Ainsi, deux types de particules magnétiques ont été comparés ; des particules antiferromagnétiques synthétiques (SAF) constituées d'empilements de couches magnétiques et des microparticules constituées d'une couche magnétique unique avec une configuration de vortex magnétique.Une fois ces particules mises en solution, les phénomènes d'auto-polarisation qui contribuent à l'agglomération / dispersion de ces particules par les interactions magnétostatiques ont été comparés, ainsi que les couples mécaniques que ces deux types de particules magnétiques peuvent générer sur les cellules cancéreuses lorsqu'elles sont soumises à un champ magnétique externe.Bien que les particules SAF génèrent de plus grands couples, remplacer les constituants de l'empilement magnétique par des matériaux biocompatibles reste délicat, ce qui n'est pas le cas de leurs homologues en vortex magnétique, facilement réalisables avec des oxydes de fer.En exploitant les propriétés des vortex magnétiques en NiFe, nous avons développé une approche pour la destruction ciblée des cellules cancéreuses du carcinome rénal humain. Les tests menés in-vitro montrent que ce stimulus magnéto-mécanique créé deux effets dramatiques : une diminution significative du taux de cellules cancéreuses vivantes, et l'initiation du processus d'apoptose (ou mort cellulaire programmée) et ce, en appliquant de faibles valeurs de champs (~100 Oe c'est-à-dire 10mT) à de très faibles fréquences (~ 20 Hz). Des études pour la quantification de la mort cellulaire par cytométrie en flux ont été menées. Les résultats déjà obtenus bien qu'au stade « preuve de concept » sont très encourageants pour le futur des nouvelles thérapies du cancerIn the coming years, the treatment of serious diseases (cancer, brain diseases, etc.) could benefit more intensely from advances in materials science and nanotechnology. From the medical point of view, it is well known that cancer cells tend to develop resistance to chemotherapy, and the side effects encountered seriously limit the effectiveness of treatments. For these reasons, the search for alternative therapies that target cancer cells without affecting healthy tissues is currently one of the most active areas of research on cancer. In this context, magnetic nanoparticles are receiving an increasing interest in a variety of applications ranging from biomedical diagnostic to targeted treatments. Indeed, due to their remote actuation by external magnetic fields, the magnetic particles have the ability to locally perform actuations on targeted biological species.This thesis describes an approach based on interfacing cancer cells with bio-functionalized magnetic particles. When these particles are bound to the cancer cells, applying an external alternating magnetic field induces the particles oscillations, which then transmits a mechanical stress to the cancer cells.For this application, specific magnetic particles were prepared. Unlike conventional magnetic particles made by chemical routes ("bottom-up"), the particles studied in this thesis have been specially designed by techniques used in micro / nanoelectronics ("top-down"). Thus, two types of magnetic particles were compared; synthetic antiferromagnetic particles (SAF) consisting of magnetic multilayer stacks and microparticles consisting of a single magnetic layer with a magnetic vortex configuration.Once these particles released in a solution, the self-polarization phenomenon that contributes to the agglomeration / dispersion of these particles by magnetostatic interactions were compared for both types of particles as well as the mechanical torques that they can exert on cancer cells when subjected to an external magnetic field.Although SAF particles generate higher torques, finding biocompatible materials that may replace the constituents of the magnetic stack remains difficult, while vortex-particles would be easier to make in magnetic iron oxides.By exploiting the properties of NiFe magnetic vortices, we have developed an approach for the targeted destruction of the human renal carcinoma cells. The tests launched in vitro show that the magneto-mechanical stimulus creates two dramatic effects: a significant decrease in the rate of alive cancer cells, and the initiation of the apoptosis (programmed cell death). These results were achieved by applying low field values (~ 100 Oe i.e.10mT) at low frequencies (~ 20 Hz). Studies for the quantification of cell death by flow cytometry were conducted. The results already obtained even at the stage of "proof of Concept" are very encouraging for new perspectives of cancer therapies
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Dupont, Bruno. "Contribution aux applications de l'interaction rayonnement matiere : métrologie sans contact par laser : modélisation de l'action sur les cellules d'un organisme vivant." Châtenay-Malabry, Ecole centrale de Paris, 1992. http://www.theses.fr/1992ECAP0239.
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L'étude est composée de trois parties : une première partie est consacrée à la description théorique classique et semi-classique des phénomènes mis en jeu lors de l'interaction entre un rayonnement (laser) et de la matière diélectrique ou conductrice. Une seconde partie traite de la transformation optique-thermique-acoustique dans laquelle l'énergie électromagnétique se transforme en chaleur, qui, du fait du fort gradient de température, crée une source de dilatation en surface engendrant des ultrasons dans le milieu. Les ultrasons, réfléchis sur les parois du milieu engendrent des phénomènes de résonance lies à la géométrie du milieu. L'analyse du signal recueilli par sonde interférométrique nous renseigne sur la géométrie et les défauts du milieu. Une dernière partie présente un modèle expliquant la génération d'ondes acoustiques par choc laser dans un milieu vivant, produisant une évolution ou même une destruction de ces cellules.
Books on the topic "Destruction of cellulose"
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De'Nadai, Alacir. Promises of jobs and destruction of work: The case of Aracruz Celulose in Brazil. Montevideo, Uruguay: World Rainforest Movement, 2005.
Find full textBook chapters on the topic "Destruction of cellulose"
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Dobele, G., T. Dizhbite, G. Rossinskaya, and G. Telysheva. "Thermocatalytic destruction of cellulose." In Cellulose and Cellulose Derivatives, 125–30. Elsevier, 1995. http://dx.doi.org/10.1533/9781845698539.2.125.
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Muneer, F. "Plastics Versus Bioplastics." In Degradation of Plastics, 193–237. m, 2021. http://dx.doi.org/10.21741/9781644901335-9.
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Plastics are polymers of long chain hydrocarbons based on petrochemicals. Due to their physiochemical properties these are almost non-degradable and their complete recycling is impossible. High production rate and less disposal capacities have made plastic environmental pollutant resulting in severe impacts on the health of organisms and destruction of habitats thus effecting the biosphere in different ways. Biodegradation, thermal and catalytic degradation of plastics is widely studied to ensure a sustainable disposal of plastic waste with limited results until the present however, a new field where ecofriendly polymers obtained from natural biomass are used to make materials is flourishing. Bioplastics are polymers derived from biomass such as cellulose, starch, chitin and microbial polyhydroxyalkanoates that have the ability to produce products of daily use that can replace their counter parts made from the synthetic plastics. Bioplastics degrade easily in natural environment and replace the petrochemical based plastic polymers, thus saving the natural environment from plastic pollution and ensuring a sustainable environment.
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Evans, Joyce A. "From Mutually Assured Destruction to Mutant Ninja Turtles." In Celluloid Mushroom Clouds, 169–76. Routledge, 2018. http://dx.doi.org/10.4324/9780429501791-11.
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Trang, Truong Thi Cam. "Study on the Use of Biomass Polymer Sheets in Water/Alcohol Pervaporation as a Sustainable Source of Alcohol Energy." In Applied Environmental Materials Science for Sustainability, 234–54. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-1971-3.ch011.
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This chapter presents an overview of the study of cellulose sheets used as a bio-membrane in water/alcohol pervaporation for a variety of purposes in order to offer an environmentally sustainable, renewable, low-energy use and economical alternative. Particular interest is the utilization of readily available biological materials such as cellulose and chitosan to create biomass polymer membranes for the environmentally responsible and sustainable process of reclaiming alcohol from alcohol/water mixtures through the use of cellulose in the pervaporation process. This process is a promising and innovative alternative to the more energy intensive, environmentally destructive methods and materials currently used.
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"Cellulite and non-surgical fat destruction." In Cosmetic Medicine and Surgery, 539–50. CRC Press, 2017. http://dx.doi.org/10.1201/9781315382364-56.
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"The degradation of cellulose acetate: Advanced analytical tools for non-destructive study of design objects." In Science and Technology for the Conservation of Cultural Heritage, 115–20. CRC Press, 2013. http://dx.doi.org/10.1201/b15577-27.
Full textConference papers on the topic "Destruction of cellulose"
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Rabadanov, G. A., Yu M. Sultanov, R. B. Appandiev, E. D. Maisarova, and Yu A. Abdulselimov. "THERMOCATALYTIC DESTRUCTION OF PINE WOOD CELLULOSE." In RENEWABLE ENERGY: CHALLENGES AND PROSPECTS. ALEF, 2020. http://dx.doi.org/10.33580/2313-5743-2020-8-1-425-429.
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Комплексная переработка возобновляемой биомассы является приоритетной задачей современной химической промышленности. Это важно как с энергетическоой, так и с эко-логической точки зрения. В работе рассмотрена термокаталитическая деструкция целлюлозы древесины сосны в присутствии катализатора - оксида алюминия. Каталитическая деструкция позволяет получать ценное сырье для нефтехимической промышленности.
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Missoum, A., A. K. Gupta, J. Chen, and Eugene L. Keating. "On the Thermal Decomposition of Solid Wastes." In ASME 1996 Design Engineering Technical Conferences and Computers in Engineering Conference. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-detc/cie-1353.
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Abstract Experimental and theoretical studies have been conducted on the thermal destruction behavior of 100% cellulose and mixture of 90% cellulose-10% polyethylene (C13H8O7) in a laboratory scale facility. A series of pyrolysis and oxidative pyrolysis (pyrolysis followed by air or oxygen addition) tests were performed. Temperature was varied from 600 to 1500K. Data provides the effect of temperature, air addition and chemical composition of the surrogate solid waste on the emissions of NOx, CO, CO2 and unburnt hydrocarbons (HC). Thermal destruction behavior of the surrogate waste is qualitatively observed to be enhanced with the progressive increase in temperature which also results in increased reduction of the material volume. Numerical calculations using equilibrium conditions are used to describe the experimentally observed trends for the thermal decomposition behavior of these materials. Analysis of the data reveals that composition of the waste as well as conditions under which the process of thermal destruction takes place (i.e., temperature, excess air or oxygen enrichment) and process type (combustion or pyrolysis) have significant influence on the product gas composition. The results also show significant effect of air enrichment on the distribution of species during pyrolysis and oxidative pyrolysis. These results reveal that controlled thermal destruction involving pyrolysis followed by combustion provides attractive benefits of high thermal destruction efficiency and low pollutants emission. This information can assist in developing strategies for the design and operation of thermal destruction facility.
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Gupta, A. K., E. Ilanchezhian, and E. L. Keating. "Influence of PVC on the Product Composition of Solid Waste During Thermal Destruction." In ASME 1994 International Computers in Engineering Conference and Exhibition and the ASME 1994 8th Annual Database Symposium collocated with the ASME 1994 Design Technical Conferences. American Society of Mechanical Engineers, 1994. http://dx.doi.org/10.1115/cie1994-0457.
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Abstract Equilibrium thermochemical calculations of a mixture of non-plastic and plastic surrogate solid waste are presented here under conditions of pyrolysis and combustion. The non-plastic waste is assumed to be cellulose while the plastic waste constituents contained the following different kinds of materials: polyethylene, polyvinyl chloride, polystyrene, polypropylene, polyethylene tetraphthalic, nylon, latex in the form of rubber, polyurethane, acetate and cellophane. The cellulose represents organic portion of the waste such as paper and cardboard. The mole fractions of different stable and unstable compounds formed during pyrolysis are significantly affected by the chemical properties of the waste. In general the amount of CO and H2O was found to remain very high at temperatures up to 2000K. while the CO2, H2O and CH4 decreased with the increase in temperature. The general trend with combustion at different mole fractions of oxygen was to achieve an increase of CO2, H2O, NO and NO2 while the concentrations of CH4, H2, CO and HCl showed a systematic decrease. The concentration and amount to different compounds formed were significantly affected with the amount of air and the chemical nature of the waste. The adiabatic flame temperature is significantly affected by the chemical composition of the plastic under conditions of combustion in air. Plastics yield significantly higher temperatures than the mixture of plastic and non-plastic waste. Experimental results showed good trend with the calculated results. Pyrolysis of waste at higher temperatures followed by combustion of resulting gases yield higher flame temperature and provides excess enthalpy of flames. The results show significant effect of controlled combustion on the amount and nature of chemical species formed as well as the subsequent flame temperature. This information can assist in developing strategies in the design and operation of facilities being used for the permanent disposal of wastes containing varying amounts of plastics.
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Missoum, A., A. K. Gupta, and E. L. Keating. "Pyrolysis of Polyethylene Terephthalate and Bisphenol-A-Polycarbonate in a Laboratory Scale Thermal Destruction Facility." In ASME 1995 15th International Computers in Engineering Conference and the ASME 1995 9th Annual Engineering Database Symposium collocated with the ASME 1995 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1995. http://dx.doi.org/10.1115/cie1995-0763.
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Abstract Results of pyrolysis tests are presented from a laboratory scale thermal destruction facility on samples containing varying composition of polyethylene terephthalate (PET) and bisphenol-A-polycarbonate (PC) mixed with non-plastic material (cellulose). Equilibrium thermochemical calculations were performed under conditions of pyrolysis. Temperature was varied from 600 to 1400K. Data provided the effect of temperature and the chemical composition of the surrogate solid waste on the emissions of NOx, CO, CO2, HC and O2. Increase in temperature enhances thermal destruction behavior of the surrogate waste which results in maximum volume reduction of the waste and an increase in the volume and heating value of the product gases. The numerical calculations using equilibrium conditions show similar trends to those obtained experimentally. Under pyrolysis conditions, the measured levels of CO, CO2 and HC were lower than the calculated ones in the temperature range of 700–1000K and higher in the 1100–1400K range. In all tests the measured O2 concentrations were higher than the calculated results. In general the level of CO was found to be very high while CO2 decreased with an increase in temperature. These results suggest that the composition of the waste as well as the conditions under which the thermal destruction process takes place, (i.e., temperature and rate of heating) affects thermal destruction. These results reveal significant effect of controlled pyrolysis on the amount and nature of species formed. This information can assist in developing strategies for the design and operation of thermal destruction facilities.
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Missoum, Azzedine, Ashwani K. Gupta, and Jianrong Chen. "Global Kinetics of the Thermal Decomposition of Materials." In ASME 1997 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/detc97/cie-4433.
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Abstract Results on the thermal destruction behavior during the decomposition of cellulose under controlled conditions are presented. Thermogravimetric (TGA) and Differential Scanning Calorimetry (DSC) tests have been carried out on the celluose samples under conditions of various heating rate and surrounding gas environment. Pyrolysis times were also measured for different size particles having different moisture contents in a controlled mixing history reactor (CMHR). The global decomposition kinetics were investigated and it was found that the decomposition process is shifts to higher temperatures at higher heating rates as a result of the competing effects of heat and mass transfer, product diffusion and the reactions kinetics. The Arrhenius parameters for pyrolysis were determined using a first order decomposition reaction of the type, dm = −km dt. It was found that the activation energy, heat of pyrolysis and char yield are a strong function of the heating rate. An increase in heating rate from 5 to 60°C/min resulted in a change of activation energy from 204.19 to 138.31 kJ/mole °C. This heating rate dependence of the kinetics is discussed. The overall decomposition process of the examined materials is generally endothermic. In general, heat transfer, mass diffusion, product evolution, heating rate, temperature and environment are the parameters that control the decomposition process. It was also shown that heat transfer and mass transport have the most effects on the decomposition process.
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Platonov, Aleksey, A. Popov, Svetlana Snegireva, and Ekaterina Kantieva. "CHANGE IN THE HYGROSCOPICITY OF PINE CORE WOOD IN A TREE TRUNK DAMAGED BY FIRE." In Modern machines, equipment and IT solutions for industrial complex: theory and practice. FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov, 2021. http://dx.doi.org/10.34220/mmeitsic2021_274-278.
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Fires have a significant impact on the structure and physical and mechanical properties of wood. The degree of this effect depends on the type of fire, its intensity and the duration of exposure to high temperature. The greatest impact on the wood occurs with a strong grassroots and general top fire. Gorenje fire is characterized by a high intensity of burning of forest floor and undergrowth, as well as the crown of trees. The effect of the high temperature of the fire on the tree trunk is different. As a result of the destruction of wood, there is a partial blocking of hydroxyl groups in the cellulose molecules and leads to a decrease in the hygroscopicity limit of wood. Of great practical interest is the change in the hygroscopicity of wood damaged by fire. The aim of this study is to determine the changes in the hygroscopicity of the core wood of Scots pine (Pinus sylvestris L.)after damage by a strong grassroots and general high-level fire. The studies were carried out on wood growing on the territory of the UOL in the Voronezh region, on samples of pine core wood cut from the clump, middle and apex parts of the trunk. It was experimentally established that the greatest decrease in the hygroscopicity of pine core wood occurred in the left part of the trunk, and the smallest in the middle part, after fire damage.
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Melnic, Maria, Dumitru Erhan, Stefan Rusu, and Olesea Gliga. "Impactul parazitar: nematoda Ditylenchus destructor–tuberculi de cartofi infestaţi în primele faze de ditilenhoză." In International symposium ”Functional ecology of animals” dedicated to the 70th anniversary from the birth of academician Ion Toderas. Institute of Zoology, Republic of Moldova, 2019. http://dx.doi.org/10.53937/9789975315975.48.
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There are presented data about morpho-physiological changes, as well as physiologico biochemicals, which appear in the tissue of potato tubers infested with Ditylenchus destructor (phases 2, 3 ditylenchose). The obtained data confirms that, D. destructor in the nutrition process eliminates in parallel celulosolitic and pectolytic enzymes, which cause complete maceration of the pectocellulosic membranes of the infected potato cell, as well as the parenchymal cortical tissue in which predominantly cellulose and pectic substances , dominating being cellulose. The results of the biochemical analyzes revealed that, at this stage in the parasite tissue there is a diminishing of the dry mass quantity, and the increase of the quantity of water. It is important to mention that in the plasmalemma mechanically traumatized by the nematode stiletto, the main intracellular inclusions of the potato tuber - the starch granules - were kept without change. Subsequently, when plasmalemma is destroyed, the granules diffuse into the nematode suspension.
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Zhang, Q., P. F. Zhang, X. X. Song, M. Zhang, Z. J. Pei, and T. Deines. "A Study on Amount of Biomass Pellets Used in Durability Testing." In ASME 2011 International Manufacturing Science and Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/msec2011-50025.
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Biofuels are an alternative to petroleum-based liquid transportation fuels. Cellulosic biomass can be used as feedstocks for befoul manufacturing. Low density of cellulosic feedstocks causes difficulties in handling them during transportation and storage, thus hindering large-scale and cost-effective manufacturing of cellulosic biofuels. Pelleting can increase the density of cellulosic feedstocks by compacting bulky biomass into pellets. Pellet durability, an important quality parameter, measures the ability of pellets to withstand impact and other destructive forces during transportation and handling. ASABE standard S269.4 specifies a procedure to determine pellet durability using 500 grams of pellets. However, it does not provide any justification of choosing this amount of pellets. This paper investigates the feasibility of using a smaller amount of pellets (50 grams) to determine pellet durability. Results show that 50 grams of pellets can generate comparable durability results as 500 grams of pellets.
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Kuzikova, Irina, Irina Kuzikova, Vera Safronova, Vera Safronova, Nadezda Medvedeva, and Nadezda Medvedeva. "IMPACT OF NONYLPHENOL ON THE PHYSIOLOGICAL ACTIVITY OF FUNGI FROM THE COASTAL AREA OF THE GULF OF FINLAND." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b431765a62a.
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Nonylphenol (NP) is the most abundant environmental estrogen listed as one of the priority hazardous substances in the Water Framework Directive (EC 2000) and the priority pollutant of Baltic Sea (HELCOM 2010). The present study aims to compare the effects of technical nonylphenol (tNP) on the cellulase, amylase and protease activity of the terrestrial fungal strains played a significant role in aquatic ecosystems due to their high adaptive capacity and a large range of functional activity. The study also attempts to understand the mechanisms behind the varying sensitivity of the terrestrial fungi to tNP. The fungal strains were isolated from the bottom sediments of the coastal area of the eastern part of the Gulf of Finland. The terrestrial fungi were identified based on their morphological characteristics and nucleotide sequence analysis of internal transcribed space region. One reason for significant differences in sensitivity to the toxicant studied among the fungi is the change in the fungal cell permeability, in particular in cell membrane permeability, induced by NP. Environmentally relevant concentrations of tNP cause significant changes in activity of hydrolytic enzymes in the terrestrial fungi Aspergillus tubingensis, Penicillium expansum, Penicillium glabrum, and Cadophora fastigiata involved in organic matter degradation in bottom sediments. There can be increasing or decreasing trend, depending on both the type of enzyme and the tNP concentration. The revealed changes may disrupt the destructive processes in bottom sediments, as well as succession and stability of microbial communities functioning in the aquatic environment. It was found that tNP contributes to the activation of proteolytic enzymes, considered as potential fungal virulence factors. This may lead to emergence fungal strains with enhanced virulence in aquatic microbiocenoses. The investigations of the physiological responses of terrestrial fungi under nonylphenol will be important for biochemical processes dynamics and their environmental consequences evaluation.
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Kuzikova, Irina, Irina Kuzikova, Vera Safronova, Vera Safronova, Nadezda Medvedeva, and Nadezda Medvedeva. "IMPACT OF NONYLPHENOL ON THE PHYSIOLOGICAL ACTIVITY OF FUNGI FROM THE COASTAL AREA OF THE GULF OF FINLAND." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b93c5890b52.86067390.
Full textAbstract:
Nonylphenol (NP) is the most abundant environmental estrogen listed as one of the priority hazardous substances in the Water Framework Directive (EC 2000) and the priority pollutant of Baltic Sea (HELCOM 2010). The present study aims to compare the effects of technical nonylphenol (tNP) on the cellulase, amylase and protease activity of the terrestrial fungal strains played a significant role in aquatic ecosystems due to their high adaptive capacity and a large range of functional activity. The study also attempts to understand the mechanisms behind the varying sensitivity of the terrestrial fungi to tNP. The fungal strains were isolated from the bottom sediments of the coastal area of the eastern part of the Gulf of Finland. The terrestrial fungi were identified based on their morphological characteristics and nucleotide sequence analysis of internal transcribed space region. One reason for significant differences in sensitivity to the toxicant studied among the fungi is the change in the fungal cell permeability, in particular in cell membrane permeability, induced by NP. Environmentally relevant concentrations of tNP cause significant changes in activity of hydrolytic enzymes in the terrestrial fungi Aspergillus tubingensis, Penicillium expansum, Penicillium glabrum, and Cadophora fastigiata involved in organic matter degradation in bottom sediments. There can be increasing or decreasing trend, depending on both the type of enzyme and the tNP concentration. The revealed changes may disrupt the destructive processes in bottom sediments, as well as succession and stability of microbial communities functioning in the aquatic environment. It was found that tNP contributes to the activation of proteolytic enzymes, considered as potential fungal virulence factors. This may lead to emergence fungal strains with enhanced virulence in aquatic microbiocenoses. The investigations of the physiological responses of terrestrial fungi under nonylphenol will be important for biochemical processes dynamics and their environmental consequences evaluation.
Reports on the topic "Destruction of cellulose"
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Manulis, Shulamit, Christine D. Smart, Isaac Barash, Guido Sessa, and Harvey C. Hoch. Molecular Interactions of Clavibacter michiganensis subsp. michiganensis with Tomato. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7697113.bard.
Full textAbstract:
Clavibacter michiganensis subsp. michiganensis (Cmm), the causal agent of bacterial wilt and canker of tomato, is the most destructive bacterial disease of tomato causing substantial economic losses in Israel, the U.S.A. and worldwide. The molecular strategies that allow Cmm, a Gram-positive bacterium, to develop a successful infection in tomato plants are largely unknown. The goal of the project was to elucidate the molecular interactions between Cmmand tomato. The first objective was to analyze gene expression profiles of susceptible tomato plants infected with pathogenic and endophytic Cmmstrains. Microarray analysis identified 122 genes that were differentially expressed during early stages of infection. Cmm activated typical basal defense responses in the host including induction of defense-related genes, production of scavenging of free oxygen radicals, enhanced protein turnover and hormone synthesis. Proteomic investigation of the Cmm-tomato interaction was performed with Multi-Dimensional Protein Identification Technology (MudPIT) and mass spectroscopy. A wide range of enzymes secreted by Cmm382, including cell-wall degrading enzymes and a large group of serine proteases from different families were identified in the xylem sap of infected tomato. Based on proteomic results, the expression pattern of selected bacterial virulence genes and plant defense genes were examined by qRT-PCR. Expression of the plasmid-borne cellulase (celA), serine protease (pat-1) and serine proteases residing on the chp/tomA pathogenicity island (chpCandppaA), were significantly induced within 96 hr after inoculation. Transcription of chromosomal genes involved in cell wall degradation (i.e., pelA1, celB, xysA and xysB) was also induced in early infection stages. The second objective was to identify by VIGS technology host genes affecting Cmm multiplication and appearance of disease symptoms in plant. VIGS screening showed that out of 160 tomato genes, which could be involved in defense-related signaling, suppression of 14 genes led to increase host susceptibility. Noteworthy are the genes Snakin-2 (inhibitor of Cmm growth) and extensin-like protein (ELP) involved in cell wall fortification. To further test the significance of Snakin -2 and ELP in resistance towards Cmm, transgenic tomato plants over-expressing the two genes were generated. These plants showed partial resistance to Cmm resulting in a significant delay of the wilt symptoms and reduction in size of canker lesion compared to control. Furthermore, colonization of the transgenic plants was significantly lower. The third objective was to assess the involvement of ethylene (ET), jasmonate (JA) and salicylic acid (SA) in Cmm infection. Microarray and proteomic studies showed the induction of enzymes involved in ET and JA biosynthesis. Cmm promoted ET production 8 days after inoculation and SIACO, a key enzyme of ET biosynthesis, was upregulated. Inoculation of the tomato mutants Never ripe (Nr) impaired in ET perception and transgenic plants with reduced ET synthesis significantly delayed wilt symptoms as compared to the wild-type plants. The retarded wilting in Nr plants was shown to be a specific effect of ET insensitivity and was not due to altered expression of defense related genes, reduced bacterial population or decrease in ethylene biosynthesis . In contrast, infection of various tomato mutants impaired in JA biosynthesis (e.g., def1, acx1) and JA insensitive mutant (jai1) yielded unequivocal results. The fourth objective was to determine the role of cell wall degrading enzymes produced by Cmm in xylem colonization and symptoms development. A significance increase (2 to 7 fold) in expression of cellulases (CelA, CelB), pectate lyases (PelA1, PelA2), polygalacturonase and xylanases (XylA, XylB) was detected by qRT-PCR and by proteomic analysis of the xylem sap. However, with the exception of CelA, whose inactivation led to reduced wilt symptoms, inactivation of any of the other cell wall degrading enzymes did not lead to reduced virulence. Results achieved emphasized the complexity involved in Cmm-tomato interactions. Nevertheless they provide the basis for additional research which will unravel the mechanism of Cmm pathogenicity and formulating disease control measures.