Journal articles: 'Nanotubes de carbone individuels'

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Vaccarini, Laetitia, Christophe Goze, Raymond Aznar, Valérie Micholet, Catherine Journet, Patrick Bernier, Karine Metenier, François Beguin, Julie Gavillet, and Annick Loiseau. "Purification des nanotubes de carbone monofeuillets." Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Astronomy 327, no. 9 (September 1999): 925–31. http://dx.doi.org/10.1016/s1287-4620(99)80156-2.

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Bussy, C., L. Tabet, J. Boczkowski, and S. Lanone. "033 Toxicité respiratoire des nanotubes de carbone." Revue des Maladies Respiratoires 24, no. 9 (November 2007): 1205. http://dx.doi.org/10.1016/s0761-8425(07)74324-3.

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Sauvajol, J. L., S. Rols, J. Cambedouzou, and R. Almairac. "Systèmes hôtes nanométriques : les nanotubes de carbone." École thématique de la Société Française de la Neutronique 12 (2007): 161–77. http://dx.doi.org/10.1051/sfn:20070013.

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Gabriel, Jean-Christophe P. "Réseaux 2d aléatoires à nanotubes de carbone." Comptes Rendus Physique 11, no. 5-6 (June 2010): 362–74. http://dx.doi.org/10.1016/j.crhy.2010.07.016.

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-SCHNELL, Jean-Philippe. "Nanotubes de carbone : état de l'art et perspectives." Revue de l'Electricité et de l'Electronique -, no. 01 (2004): 24. http://dx.doi.org/10.3845/ree.2004.002.

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Meunier, V., and P. Lambin. "Propriétés structurales des jonctions de nanotubes de carbone." Canadian Journal of Physics 77, no. 9 (February 1, 2000): 667–75. http://dx.doi.org/10.1139/p99-004.

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The junction between two different nanotubes can be realized by the simple insertion of a pentagon-heptagon pair defect while preserving the triple coordination of each C atom. This insertion bends the structure to an angle depending on the distance between the pentagonand heptagon. The atomic structure of several of these junctions was optimized with the help of empirical potentials, the nanotubes on both sides of the junctions being considered as infinitely long. Local densities of σ + π electronic states were evaluated in the interfacial regions from a tight-binding Hamiltonian. From there, the electronic energy of these junctions was calculated and compared with that of the isolated nanotubes. It was established that the energy associated with the pentagon-heptagone pair in a graphitic tubule is of the order of 6 eV. An automatic generation algorithm for connecting any two tubules was developed. By restricting the Hamiltonian to the sole π orbitals, this algorithm made it feasible to study the energetics of the pentagon-heptagon defect in a systematical way.

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Meunier, V., and P. Lambin. "Propriétés structurales des jonctions de nanotubes de carbone." Canadian Journal of Physics 77, no. 9 (1999): 667–75. http://dx.doi.org/10.1139/cjp-77-9-667.

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Jaffiol, R., A. Débarre, D. Nutarelli, A. Richard, and P. Tchénio. "Imagerie Raman hyper-spectrale de nanotubes de carbone dopés." Journal de Physique IV (Proceedings) 12, no. 5 (June 2002): 285–86. http://dx.doi.org/10.1051/jp4:20020163.

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Bianco, Alberto. "Les nanotubes de carbone : un nouvel outil contre le cancer." médecine/sciences 25, no. 2 (February 2009): 125–27. http://dx.doi.org/10.1051/medsci/2009252125.

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Azrar, A., L. Azrar, and A. A. Aljinaidi. "Nonlinear free vibration of single walled Carbone NanoTubes conveying fluid." MATEC Web of Conferences 11 (2014): 02015. http://dx.doi.org/10.1051/matecconf/20141102015.

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Kim, Sung-Hyun, Dong Han Lee, Jin Hee Lee, Jun-Young Yang, Hyo-Sook Shin, JeongPyo Lee, Kikyung Jung, Jayoung Jeong, Jae-Ho Oh, and Jong Kwon Lee. "Evaluation of the Skin Sensitization Potential of Carbon Nanotubes Using Alternative In Vitro and In Vivo Assays." Toxics 8, no. 4 (December 16, 2020): 122. http://dx.doi.org/10.3390/toxics8040122.

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Carbon nanotubes (CNTs) are one of the major types of nanomaterials that have various industrial and biomedical applications. However, there is a risk of accidental exposure to CNTs in individuals involved in their large-scale production and in individuals who use products containing CNTs. This study aimed to evaluate the skin sensitization induced by CNTs using two alternative tests. We selected single-wall carbon nanotubes and multi-walled carbon nanotubes for this study. First, the physiochemical properties of the CNTs were measured, including the morphology, size, and zeta potential, under various conditions. Thereafter, we assessed the sensitization potential of the CNTs using the ARE-Nrf2 Luciferase KeratinoSens™ assay, an in vitro alternative test method. In addition, the CNTs were evaluated for their skin sensitization potential using the LLNA: BrdU-FCM in vivo alternative test method. In this study, we report for the first time the sensitization results of CNTs using the KeratinoSens™ and LLNA: BrdU-FCM test methods in this study. This study found that both CNTs do not induce skin sensitization. These results suggest that the KeratinoSens™ and LLNA: BrdU-FCM assay may be useful as alternative assays for evaluating the potential of some nanomaterials that can induce skin sensitization.

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Rouway, M., Z. Boulahia, N. Chakhchaoui, O. Cherkaoui, LH Omari, and F. Fraija. "Graphene and Carbone nanotubes reinforced ceramic nanocomposite TiO2-MgO: Experimental and numerical study." Materials Today: Proceedings 30 (2020): 809–15. http://dx.doi.org/10.1016/j.matpr.2020.04.177.

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Strasinger, Caroline L., Nicole N. Scheff, Ji Wu, Bruce J. Hinds, and Audra L. Stinchcomb. "Carbon Nanotube Membranes for use in the Transdermal Treatment of Nicotine Addiction and Opioid Withdrawal Symptoms." Substance Abuse: Research and Treatment 3 (January 2009): SART.S1050. http://dx.doi.org/10.4137/sart.s1050.

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Transdermal systems are attractive methods of drug administration specifically when treating patients for drug addiction. Current systems however are deficient in therapies that allow variable flux values of drug, such as nicotine for smoking cessation or complex dosing regimens using clonidine when treating opioid withdrawal symptoms. Through the use of functionalized carbon nanotube (CNT) membranes, drug delivery to the skin can be controlled by applying a small electrical bias to create a programmable drug delivery system. Clearly, a transdermal patch system that can be tailored to an individual's needs will increase patient compliance as well as provide much more efficient therapy. The purpose of this paper is to discuss the applicability of using carbon nanotube membranes in transdermal systems for treatment of drug abuse.

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Facca, Sybille, Debrupa Lahiri, Florence Fioretti, Philippe Liverneaux, Nadia Benkirane-Jessel, and Arvind Agarwal. "Amélioration de l’ostéointégration d’implants en titane recouverts d’hydroxyapatite et de nanotubes de carbone : étude in vivo." Revue de Chirurgie Orthopédique et Traumatologique 97, no. 7 (November 2011): S346—S347. http://dx.doi.org/10.1016/j.rcot.2011.08.265.

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Facca, S., D. Lahiri, F. Fioretti, P. Liverneaux, N. Jessel, and A. Agarwal. "Nanorenforcement de surface d’implants en titane recouverts d’hydroxyapatite et de nanotubes de carbone : étude in vivo." Revue de Chirurgie Orthopédique et Traumatologique 98, no. 5 (September 2012): 548–49. http://dx.doi.org/10.1016/j.rcot.2012.06.051.

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Troudi, M., A. Mahmoudi, N. Sghaier, and A. Soltani. "Theoretical Modeling of a Photodetector Based on Ballistic Carbone Nanotube with VHDL-AMS." International Letters of Chemistry, Physics and Astronomy 55 (July 2015): 112–18. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.55.112.

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In this paper we present a new VHDL-AMS model of carbone nanotube field effect transistor for photo-detection application: (photo-CNTFET). Contrary to classical photodetectors, the photo-CNTFET has the potential to work on a wide range of optical frequencies and high quantum efficiency and can be used as a highly sensitive and rapid response photodetector. Based on its excellent conductivity and very low capacitance, Carbon nanotubes provide highly mobile electrons and low noise in the system. The simulation results obtained in the present paper has shown its relevance as precise and fast tool to investigate the effects of photoexcitation on Ids-Vds characteristics of the photo-CNTFET. We have present results obtained after variation of power illumination and light beam wavelength.

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Mufida, Erika Marinda, Sri Wahyu Suciyati, Gurum Ahmad Pauzi, and Amir Supriyanto. "Kajian Simulasi Dinamika Molekul Adsorpsi Hidrogen pada Carbone Nanotube dengan Variasi Chirality dan Temperatur Menggunakan Kode LAMMPS." Journal of Energy, Material, and Instrumentation Technology 2, no. 2 (May 31, 2021): 40–50. http://dx.doi.org/10.23960/jemit.v2i2.58.

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Hydrogen adsorption has been simulated on carbon nanotubes for optimum hydrogen absorption. Parameters that affect the amount of hydrogen absorbed have been studied, such as the effect of chirality and temperature on hydrogen absorption in CNTs. The simulation method of hydrogen adsorption on carbone nanotubes uses molecular dynamics simulation code LAMMPS, applies Lennard-Jones interatomic potential and hydrogen atom movement using Van Der Waals force with Microcanonical Ensemble. Data analysis is the output of LAMPS in the form of data in XYZ format. The data contains information in the form of integration steps, number of atoms, temperature, pressure, potential energy, kinetic energy, volume, van der Waals energy, total simulation time and hydrogen absorption. The simulation results show that the optimum absorption occurs at run 10000 and a temperature of 100 K, for armchair chirality of 10 atoms, chirality of 12 atoms and zigzag chrality of 5 atoms. Formation of hydrogen coordinates with Avogadro software, formation of CNT coordinates with VMD software and visualization of hydrogen adsorption on CNTs using VMD software.

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Kolsi, Lioua, Hakan Oztop, Kaouther Ghachem, Mohammed Almeshaal, Hussein Mohammed, Houman Babazadeh, and Nidal Abu-Hamdeh. "Numerical Study of Periodic Magnetic Field Effect on 3D Natural Convection of MWCNT-Water/Nanofluid with Consideration of Aggregation." Processes 7, no. 12 (December 14, 2019): 957. http://dx.doi.org/10.3390/pr7120957.

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In this paper, a numerical study is performed to investigate the effect of a periodic magnetic field on three-dimensional free convection of MWCNT (Mutli-Walled Carbone Nanotubes)-water/nanofluid. Time-dependent governing equations are solved using the finite volume method under unsteady magnetic field oriented in the x-direction for various Hartmann numbers, oscillation periods, and nanoparticle volume fractions. The aggregation effect is considered in the evaluation of the MWCNT-water/nanofluid thermophysical properties. It is found that oscillation period, the magnitude of the magnetic field, and adding nanoparticles have an important effect on heat transfer, temperature field, and flow structure.

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Mahmoudi, Noureddine. "Amélioration des propriétés mécaniques et tribologiques d’un composite de base PEEK par l’addition de nanotubes de carbone." Annales de chimie Science des Matériaux 39, no. 1-2 (June 28, 2015): 1–10. http://dx.doi.org/10.3166/acsm.39.1-10.

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Abalymov, Anatolii, Louis Van der Meeren, Dmitry Volodkin, Bogdan Parakhonskiy, and Andre G. Skirtach. "Carbon Nanotubes Transform Soft Gellan Gum Hydrogels into Hybrid Organic–Inorganic Coatings with Excellent Cell Growth Capability." C 7, no. 1 (February 4, 2021): 18. http://dx.doi.org/10.3390/c7010018.

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Carbone nanotubes (CNTs) possess distinct properties, for example, hardness, which is very complementary to biologically relevant soft polymeric and protein materials. Combining CNTs with bio-interfaces leads to obtaining new materials with advanced properties. In this work, we have designed novel organic-inorganic hybrid coatings by combining CNTs with gellan gum (GG) hydrogels. The surface topography of the samples is investigated using scanning electron microscopy and atomic force microscopy. Mechanical properties of synthesized hybrid materials are both assessed at the macro-scale and mapped at the nanoscale. A clear correlation between the CNT concentration and the hardness of the coatings is revealed. Cell culture studies show that effective cell growth is achieved at the CNT concentration of 15 mg/mL. The presented materials can open new perspectives for hybrid bio-interfaces and can serve as a platform for advanced cell culture.

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Oksengorn, Boris. "Stockage de l’hydrogène dans les nanotubes de carbone à paroi unique : nouvelle méthode de préparation par excitation laser." Comptes Rendus Chimie 13, no. 10 (October 2010): 1313–18. http://dx.doi.org/10.1016/j.crci.2010.03.023.

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Martinelli, Natália Marassi, Maria Julia Galera, Miller De Almeida Marques, Ritchelli Ricci, Anderson De Oliveira Lobo, and Fernanda Roberta Marciano. "BIOCOMPATIBILIDADE EM FILMES DE HIDROXIAPATITA REFORÇADA COM NANOTUBOS DE CARBONO." Revista Univap 22, no. 40 (November 3, 2016): 90. http://dx.doi.org/10.18066/revistaunivap.v22i40.1556.

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As características químicas e estruturais individuais de nanotubos de carbono (NTC) e hidroxiapatita (HAp), principal constituinte da fase inorgânica do osso, possibilitam seu uso na área médica como materiais biocompatíveis em implantes e próteses. O objetivo deste trabalho é estudar a biocompatibilidade do compósito HAp/NTC eletrodepositadas comitantemente em aço 316. Para a produção dos compósitos os NTC foram dispersos na solução eletrolítica em concentrações de 1% e 3%. Os resultados obtidos in vitro, utilizando o ensaio da Lactato Desidrogenase (LDH), demostraram que nenhuma amostra causou citotoxicidade nas células osteoblásticas. Neste estudo, também foram avaliados genes relacionados à osteogênese, tais como: fosfatase alcalina (ALP), osteopontina (OPN), osteocalcina (OC) por RT-qPCR (Transcrição Reversa – Reação em Cadeia da Polimerase quantitativa), após 14 dias. Os osteoblastos em contato com a HAp/NTC apresentaram aumento da expressão de genes importantes no processo de mineralização e maturação óssea. Os resultados demonstraram um grande potencial de aplicação clínica deste compósito.

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Biloivan, O. A., N. S. Rogaleva, and Ya I. Korpan. "Optimization of bioselective membrane of amperometric enzyme sensor on basis of glucose oxidase using NH2-modified multi-wall carbone nanotubes." Biopolymers and Cell 26, no. 1 (January 20, 2010): 56–61. http://dx.doi.org/10.7124/bc.000145.

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Kakehi, Kazunori, Suguru Noda, Shigeo Maruyama, and Yukio Yamaguchi. "Individuals, grasses, and forests of single- and multi-walled carbon nanotubes grown by supported Co catalysts of different nominal thicknesses." Applied Surface Science 254, no. 21 (August 2008): 6710–14. http://dx.doi.org/10.1016/j.apsusc.2008.04.050.

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Abdolmohammadi, Shahrzad. "TiO2 NPs-Coated Carbone Nanotubes as a Green and Efficient Catalyst for the Synthesis of [1]Benzopyrano[b][1]benzopyranones and Xanthenols in Water." Combinatorial Chemistry & High Throughput Screening 21, no. 8 (December 17, 2018): 594–601. http://dx.doi.org/10.2174/1386207321666181018164739.

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Aim and Objective: Results of pharmacological studies have revealed that chromenes (2H-1-benzopyran derivatives) and xanthenes (dibenzopyrans) constitute major classes of heterocyclic compounds, due to their useful biological activities. Moreover, during the last decade, the use of metal oxide nanoparticles (NPs) as heterogeneous catalysts has been extensively studied due to their high physical and chemical abilities. The aim of the ongoing research was to prove the catalytic efficiency of the synthesized TiO2 NPs supported by carbon nanotubes (TiO2-CNTs) for the preparation of these heterocyclic scaffolds. Materials and Methods: The present work is focused on a green and efficient synthesis of [1]benzopyrano[b][1]benzopyran-6-ones and xanthenols via a pseudo three-component reaction of salicylaldehydes with active methylene compounds including 4-hydroxycoumarin (4-hydroxy-2H-1- benzopyran-2-one) or 3,4-methylenedioxyphenol, in a molar ratio of 1:2. The reaction was carried out in the presence of the synthesized TiO2-CNTs as a catalyst in aqueous media at room temperature. The synthesized catalyst was fully characterized by the scanning electron microscopy (SEM), the transmission electron microscopy (TEM), the powder X-ray diffraction (XRD), and the energy dispersive X-ray detector (EDX) techniques. All the synthesized compounds were characterized by IR, 1H and 13C NMR spectroscopy, as well as elemental analyses. Results: Sixteen target compounds containing [1]benzopyrano[b][1]benzopyran-6-ones and xanthenols were successfully synthesized in high yields (92-98%) within short reaction times (1.5-3 h). Conclusion: In this research, TiO2-CNTs were used as an efficient recyclable catalyst for the synthesis of [1]benzopyrano[b][1]benzopyran-6-ones and xanthenols by the pseudo three-component reaction of salicylaldehydes with active methylene compounds including 4-hydroxycoumarin (4- hydroxy-2H-1-benzopyran-2-one) or 3,4-methylenedioxyphenol. The introduced method is mild, environmentally benign and effective to give the products in high yields and in short reaction times.

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Borodkin, A. A., D. V. Khudyakov, and S. K. Vartapetov. "Investigation of hybrid modulator based on nonlinear optical loop mirror and single-walled carbone nanotubes for mode-locking in Yb-doped ultrafast fiber laser." Journal of Physics: Conference Series 941 (December 2017): 012001. http://dx.doi.org/10.1088/1742-6596/941/1/012001.

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Anisimova, Anna A., Olga N. Lukyanova, Vladimir V. Chaika, Alexandra A. Kalitnik, Svetlana A. Danilenko, Vladimir L. Kuznetsov, and Kirill S. Golokhvast. "Short-Time Effect of Multi-Walled Carbon Nanotubes on Some Histological and Biochemical Parameters in Marine Bivalves Crenomytilus grayanus (Dunker, 1853) and Swiftopecten swifti (Bernardi, 1858)." Nano Hybrids and Composites 13 (January 2017): 225–31. http://dx.doi.org/10.4028/www.scientific.net/nhc.13.225.

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The marine bivalves, mussels Crenomytilus grayanus (Dunker, 1853) and scallops Swiftopecten swifti (Bernardi, 1858), were in vivo exposed to 12-14 nm multi-walled carbon nanotubes (MWNTs) for up to 48 h. Microscopic analysis in combination with the RAMAN spectrophotometry revealed the MWNT aggregates on the gills surface and inside the gut of all exposed individuals. After 48 h exposure, there were no changes in the total cell count, the average cell size and granularity in the hemolymph of mussels, while in the scallops the total hemocyte count was significantly reduced, and the average hemocyte granularity increased. Biochemical markers of oxidative stress (activity of glutathione-S-transferase and catalase, concentration of reduced glutathione, and the degree of lipid peroxidation) did not change significantly in the digestive gland of both mussels and scallops. In hemolymph, catalase activity increased as compared to control in both mussels and scallops. Moreover, concentration of reduced glutathione increased in hemolymph of scallops on the second day of exposure to MWNTs. The data obtained indicate that MWNTs may affect different bivalve mollusks more or less strongly under the same exposure conditions.

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Mao, Chen-Chen, and Xiaoxiao Cai. "Nanomaterials and Aging." Current Stem Cell Research & Therapy 16, no. 1 (December 1, 2021): 57–65. http://dx.doi.org/10.2174/1574888x15666200422103916.

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As the proportion of the elderly population increases, more and more people suffer from aging-related diseases. Even if aging is inevitable, prolonging the time of healthy aging, delaying the progression of aging-related diseases, and the incidence of morbidity can greatly alleviate the pressure on individuals and society. Current research and exploration in the field of materials related to aging are expanding tremendously. Here, we present a summary of recent research in the field of nanomaterials relevant to aging. Some nanomaterials, such as silica nanomaterials (NMs) and carbon nanotubes, cause damage to the cells similar to aging processes. Other nanomaterials such as fullerenes and metalbased nanomaterials can protect the body from endogenous and exogenous harmful substances such as ROS by virtue of their excellent reducing properties. Another new type of nucleic acid nanomaterial, tetrahedral framework nucleic acids, works effectively against cell damage. This material selectively clears existing senescent cells in the tissue and thus prevents the development of the chronic inflammatory environment caused by senescent cells secreting senescence-associated secretory phenotype to the surroundings. We believe that nanomaterials have tremendous potential to advance the understanding and treatment of aging-related disorders, and today's research only represents the beginning stages.

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Jasani, Bharat, and Allen Gibbs. "Mesothelioma Not Associated With Asbestos Exposure." Archives of Pathology & Laboratory Medicine 136, no. 3 (March 1, 2012): 262–67. http://dx.doi.org/10.5858/arpa.2011-0039-ra.

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Context.—Despite asbestos being identified as the single most important cause of malignant mesothelioma, the tumor is known to occur in only 10% to 20% of heavily exposed individuals. In addition, about 20% of the patients have no history of asbestos exposure even after detailed assessment. Therefore, there has been speculation for some time that asbestos alone may not be sufficient to cause mesothelioma and that other factors may be involved either as cocarcinogens or as independent mechanisms of cancer causation. Objective.—To give a brief review of nonasbestos fiber erionite and therapeutic radiation as 2 established examples of asbestos-independent mechanisms, of the potential emerging role of man-made fibers such as carbon nanotubes, and of polyoma virus SV40 (simian virus 40) as a potential example of the cocarcinogenic mode of involvement. Data Sources.—Relevant recent literature has been surveyed to portray and provide the evidence in favor of the examples. Conclusions.—Erionite has emerged as the most important example of nonasbestos-mediated cause of mesothelioma in regions such as Turkey where exposure to this type of fiber is highly prevalent. Recently, the polyoma virus SV40 has been unexpectedly discovered as an effective cocarcinogen of asbestos in the causation of animal mesothelioma, though despite considerable research, its potential role in human mesothelioma remains unproven.

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Günter, Sven, Michael Weber, Bernd Stimm, and Reinhard Mosandl. "Lier la sylviculture tropicale à la gestion forestière durable." BOIS & FORETS DES TROPIQUES 314, no. 314 (December 1, 2012): 25. http://dx.doi.org/10.19182/bft2012.314.a20487.

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Depuis l'émergence du concept de la " gestion durable des ressources " dans les dernières décennies du XXe siècle, les aspects écologiques, technologiques et socio-économiques constituent les piliers de la gestion forestière durable. Alors que la production de bois et de produits forestiers non ligneux (PFNL) a longtemps été l'objectif premier de la gestion forestière, la demande de services forestiers écologiques s'accroît aujourd'hui en parallèle. Cependant, les systèmes de gestion forestière tropicale ont été conçus pour la plupart il y a fort longtemps, avec pour but principal la production de bois. Cet article présente une approche en six étapes pour passer de la sylviculture tropicale classique axée sur la production de bois à des approches plus globales visant à assurer une gestion réellement durable des ressources forestières. Cet objectif est particulièrement important sous les tropiques, où la production de bois est désormais menacée par un rythme de déforestation alarmant et par l'importance accrue des ressources forestières pour assurer la subsistance des populations locales. L'augmentation des superficies forestières concurrence fortement les autres objectifs d'utilisation des terres, et l'intensification permettant d'accroître la production à l'hectare est donc une approche prometteuse pour résoudre ce problème majeur, par exemple par la mise en oeuvre des techniques sylvicoles à rotations courtes, la domestication d'essences ou l'aménagement des sites. La diversification des structures et des services forestiers est une stratégie complémentaire importante visant à remédier à la dégradation éventuelle des forêts et aux pénuries d'autres biens ou services, et de ce fait à contribuer à la gestion durable à l'échelle d'un paysage. Les échelles de gestion, temporelles et spatiales, doivent donc être adaptées aux besoins des exploitants forestiers individuels (pour la production de bois, par exemple) mais aussi à ceux de la collectivité (eau, biodiversité, stockage du carbone...). La gestion forestière durable dépend fortement de son acceptation par l'ensemble des intéressés, et les approches participatives peuvent y contribuer de façon significative. Cet article présente des exemples montrant comment l'intégration de la sylviculture et de la gestion forestière permet, en englobant tous les aspects indiqués ci-dessus, de contrer la gestion de conception purement extractive pour aboutir à une approche sylvicole moderne en termes de gestion adaptive de l'écosystème. L'autonomie des acteurs sociaux et des mécanismes de marché opérationnels pour les produits et services autres que le bois sont des éléments incontournables de la planification sylvicole moderne, mais n'ont aucune utilité pour la gestion forestière durable tant qu'ils ne s'accompagnent pas d'une solide connaissance des fonctions et processus écologiques et d'une bonne compréhension des impacts des interventions humaines. La sylviculture tropicale et la gestion durable des forêts dépendent l'une comme l'autre de la connaissance des écosystèmes et de son application pratique sur le terrain.

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Crintea, Andreea, Alina Gabriela Dutu, Gabriel Samasca, Ioan Alexandru Florian, Iulia Lupan, and Alexandra Marioara Craciun. "The Nanosystems Involved in Treating Lung Cancer." Life 11, no. 7 (July 13, 2021): 682. http://dx.doi.org/10.3390/life11070682.

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Even though there are various types of cancer, this pathology as a whole is considered the principal cause of death worldwide. Lung cancer is known as a heterogeneous condition, and it is apparent that genome modification presents a significant role in the occurrence of this disorder. There are conventional procedures that can be utilized against diverse cancer types, such as chemotherapy or radiotherapy, but they are hampered by the numerous side effects. Owing to the many adverse events observed in these therapies, it is imperative to continuously develop new and improved strategies for managing individuals with cancer. Nanomedicine plays an important role in establishing new methods for detecting chromosomal rearrangements and mutations for targeted chemotherapeutics or the local delivery of drugs via different types of nano-particle carriers to the lungs or other organs or areas of interest. Because of the complex signaling pathways involved in developing different types of cancer, the need to discover new methods for prevention and detection is crucial in producing gene delivery materials that exhibit the desired roles. Scientists have confirmed that nanotechnology-based procedures are more effective than conventional chemotherapy or radiotherapy, with minor side effects. Several nanoparticles, nanomaterials, and nanosystems have been studied, including liposomes, dendrimers, polymers, micelles, inorganic nanoparticles, such as gold nanoparticles or carbon nanotubes, and even siRNA delivery systems. The cytotoxicity of such nanosystems is a debatable concern, and nanotechnology-based delivery systems must be improved to increase the bioavailability, biocompatibility, and safety profiles, since these nanosystems boast a remarkable potential in many biomedical applications, including anti-tumor activity or gene therapy. In this review, the nanosystems involved in treating lung cancer and its associated challenges are discussed.

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Johnson, A. T. Charlie, Christopher Kehayias, Erica L. Carpenter, Jody Piltz-Seymour, Janos Laszlo Tanyi, Cindy Otto, Young Eun Lee, Taylor A. Black, Stephanie S. Yee, and George Preti. "Nanoanalysis of plasma volatile organic compounds using novel DNA-decorated carbon nanotube vapor sensors to noninvasively distinguish ovarian and pancreatic cancer from benign and control samples." Journal of Clinical Oncology 39, no. 15_suppl (May 20, 2021): 5544. http://dx.doi.org/10.1200/jco.2021.39.15_suppl.5544.

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5544 Background: All cells release volatile organic compounds (VOCs) which emanate from body fluids. Our previous preliminary proof of concept study demonstrated that VOCs released from tissue and plasma from ovarian cancer patients are distinct from those released from samples of patients with benign tumors and controls. We seek to create a sensitive and specific, high-throughput screening test for cancer based on analysis of VOCs using novel nanosensors, first targeting cancers with limited clinical screening modalities. In this study we use these sensors to distinguish vapor characteristics in plasma samples from patients with ovarian and pancreatic cancer from benign specimens and controls. Methods: VOCs emanating from.5 mL of thawed, previously banked plasma samples from 93 total individuals were analyzed using a 10-channel nanoelectronic olfaction (“e-nose”) system based on single-stranded DNA-decorated single-walled carbon nanotube (DNA-NT) vapor sensors. Analysis was performed on samples from 20 patients with ovarian cancer, 20 with benign ovarian tumors and 20 age-matched women as well as 13 patients with pancreatic cancer, 10 patients with benign pancreatic disease, and 10 age- and sex-matched controls. All ovarian cancer patients and comparators were non-smokers, while 1 pancreatic patient and 1 corresponding control were current smokers. The sample set included cancer patients with both early- and late-stage disease. All cancer specimens were obtained proximal to initial diagnosis and prior to initiation of therapy. With a test time of approximately 20 minutes per sample, the array output for each individual sample creates a vector in a 10-dimensional sensor space. The ability of the nanosensor array to discriminate between malignant, benign, and healthy groups was investigated using linear discriminant analysis (LDA), support vector machine (SVM), k-nearest neighbors (KNN), and random forest classification algorithms. Each algorithm was trained and tested according to leave-one-out and repeated stratified k-fold cross-validation methods. Results: Compared to their corresponding benign and control specimens, the DNA-NT sensor array was able to discriminate the VOCs from ovarian cancer with 95% accuracy and pancreatic cancer with 90% accuracy. Plasma samples from patients with early-stage ovarian and pancreatic cancers were correctly identified by the algorithms. Conclusions: Nano-enabled DNA coated vapor sensors were able to distinguish the VOC pattern between cancer, benign and control samples in both ovarian and pancreatic cancer. We provide strong evidence that ovarian and pancreatic cancer alters the VOC pattern emanating from plasma. Our results provide optimism that a diagnostic approach based on vapor detection of ovarian and pancreatic cancer is achievable.

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Allami, Tyser, Ahmed Alamiery, Mohamed H. Nassir, and Amir H. Kadhum. "Investigating Physio-Thermo-Mechanical Properties of Polyurethane and Thermoplastics Nanocomposite in Various Applications." Polymers 13, no. 15 (July 27, 2021): 2467. http://dx.doi.org/10.3390/polym13152467.

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The effect of the soft and hard polyurethane (PU) segments caused by the hydrogen link in phase-separation kinetics was studied to investigate the morphological annealing of PU and thermoplastic polyurethane (TPU). The significance of the segmented PUs is to achieve enough stability for further applications in biomedical and environmental fields. In addition, other research focuses on widening the plastic features and adjusting the PU–polyimide ratio to create elastomer of the poly(urethane-imide). Regarding TPU- and PU-nanocomposite, numerous studies investigated the incorporation of inorganic nanofillers such as carbon or clay to incorporating TPU-nanocomposite in several applications. Additionally, the complete exfoliation was observed up to 5% and 3% of TPU–clay modified with 12 amino lauric acid and benzidine, respectively. PU-nanocomposite of 5 wt.% Cloisite®30B showed an increase in modulus and tensile strength by 110% and 160%, respectively. However, the nanocomposite PU-0.5 wt.% Carbone Nanotubes (CNTs) show an increase in the tensile modulus by 30% to 90% for blown and flat films, respectively. Coating PU influences stress-strain behavior because of the interaction between the soft segment and physical crosslinkers. The thermophysical properties of the TPU matrix have shown two glass transition temperatures (Tg’s) corresponding to the soft and the hard segment. Adding a small amount of tethered clay shifts Tg for both segments by 44 °C and 13 °C, respectively, while adding clay from 1 to 5 wt.% results in increasing the thermal stability of TPU composite from 12 to 34 °C, respectively. The differential scanning calorimetry (DSC) was used to investigate the phase structure of PU dispersion, showing an increase in thermal stability, solubility, and flexibility. Regarding the electrical properties, the maximum piezoresistivity (10 S/m) of 7.4 wt.% MWCNT was enhanced by 92.92%. The chemical structure of the PU–CNT composite has shown a degree of agglomeration under disruption of the sp2 carbon structure. However, with extended graphene loading to 5.7 wt.%, piezoresistivity could hit 10−1 S/m, less than 100 times that of PU. In addition to electrical properties, the acoustic behavior of MWCNT (0.35 wt.%)/SiO2 (0.2 wt.%)/PU has shown sound absorption of 80 dB compared to the PU foam sample. Other nanofillers, such as SiO2, TiO2, ZnO, Al2O3, were studied showing an improvement in the thermal stability of the polymer and enhancing scratch and abrasion resistance.

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Lakbita, Imane, and Khalil El-Hami. "Etude et élaboration prédictive d’un nanocondensateur à base des nanotubes de carbone." Incertitudes et fiabilité des systèmes multiphysiques 17, no. 2 (November 2017). http://dx.doi.org/10.21494/iste.op.2017.0184.

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Mammeri, Fayna, Andrea Ballarin, Marion Giraud, Lydie Vivet, Frederic Herbst, Carole Connan, Mohamed M. Chehimi, Giovanna Brusatin, and Souad Ammar. "Design of CdS Quantum Dots / Multi-Walled Carbon Nanotubes Hybrid Structures for Photovoltaic Applications." MRS Proceedings 1359 (2011). http://dx.doi.org/10.1557/opl.2011.1017.

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ABSTRACTThis paper presents the preparation of multi-walled carbone nanotubes (CNTs) and CdS nanoparticles based hybrid materials. We aim at comparing two kinds of CNTs’ functionalization by thiol groups in order to demonstrate that the surface chemistry done on the CNTs can direct the morphology of the nanohybrids. Indeed, strong oxidation of CNTs leads to shorter nanotubes opened at their ends, allowing the grafting of mercaptotriethoxysilane whereas the generation of diazonium salts in presence of pristine nanotubes should lead to the functionalization of the whole lateral surface of the nanotubes. CdS nanoparticles can then be anchored to thiol groups, leading to interesting hybrid precursors for photovoltaic applications.

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Journal articles on the topic 'Nanotubes de carbone individuels'

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