The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
M.h. Grant - One of the best experts on this subject based on the ideXlab platform.
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Investigation into the biological stability of collagen/chondroitin-6-sulphate gels and their contraction by fibroblasts and keratinocytes : The effect of crosslinking agents and diamines
Biomaterials, 1999Co-Authors: C. S Osborne, W. H Reid, M.h. GrantAbstract:Abstract Artificial skin substitutes based on autologous keratinocytes cultured on collagen-based substrata are being developed for grafting onto patients with severe burns. The properties of the substratum can be manipulated by crosslinking the collagen with the glysocaminoglycan, chondroitin-6-sulphate (Ch6SO 4 ), Carbodiimides and polyamines. Biological stability, assessed by resistance to collagenase, was increased by incorporation of Ch6SO 4 , but crosslinking with the Carbodiimides, 1-ethyl-3-(dimethylamino-propyl)Carbodiimide and 1,1-carbonyldiimidazole or the polyamines, putrescine or diaminohexane, had little further benefit. Contraction of the collagen gels occurred to a greater extent when seeded with fibroblasts than with keratinocytes. The extent of contraction by either cell type was not influenced by the presence of Ch6SO 4 in the gel, but the Carbodiimides, and to a lesser extent the polyamines, limited cell-mediated contraction, particularly that mediated by fibroblasts. Optimum substratum composition for artificial skin substitutes will involve a compromise between the desired attributes of biological stability, rate of contraction, mechanical strength, biocompatibility and promotion of cell growth.
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Investigation into cell growth on collagen/chondroitin-6-sulphate gels: the effect of crosslinking agents and diamines
Journal of Materials Science: Materials in Medicine, 1997Co-Authors: C. S Osborne, W. H Reid, M.h. GrantAbstract:Artificial skin substitutes based on cultured autologous keratinocytes need to have sufficient strength and ease of handling to be utilized successfully by surgeons in the clinic. This may be achieved by crosslinking the collagen substratum on which the cells are cultured, which in this case is a collagen gel. Increased strength must be attained without detrimental effect on cell growth. The influence of potential crosslinking agents including the glycosaminoglycan, chondroitin-6-sulphate (Ch6SO4), the water soluble Carbodiimide crosslinking agents 1-ethyl-3-(3-diaminopropyl) Carbodiimide (EDAC), and 1,1-carbonyldiimidazole (CDI), and the polyamines putrescine, spermine and diaminohexane, on cell growth rate has been investigated. Incorporation of 20% Ch6SO4 into collagen gels caused an approximately 16% increase in keratinocyte growth, but had no significant effect on that of dermal fibroblasts. Pre-formed collagen gels (+/− Ch6SO4) were treated with the Carbodiimides. This crosslinking treatment markedly inhibited fibroblast growth (EDAC 45% inhibition, CDI 70%), without affecting that of keratinocytes. Pre-formed collagen gels (+/−Ch6SO4 and Carbodiimide) were treated with 0.1 M, 0.5 M or 1.0 M polyamine. Spermine inhibited the growth rate of both cell types at all concentrations tested, whereas putrescine and diaminohexane had little effect. The mechanical strength of these crosslinked gels is currently being assessed to determine the optimum composition in terms of cell growth and biocompatibility, and strength.
Lorenzo Stievano - One of the best experts on this subject based on the ideXlab platform.
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Reversible High Capacity and Reaction Mechanism of Cr 2 (NCN) 3 Negative Electrodes for Li‐Ion Batteries
Energy Technology, 2020Co-Authors: Jeethu Jiju Arayamparambil, Moulay Tahar Sougrati, Richard Dronskowski, Jeethu Arayamparambil, Markus Mann, Kaixuan Chen, Antonella Iadecola, Xianji Qiao, Bernard Fraisse, Lorenzo StievanoAbstract:A detailed study of the electrochemical reaction mechanism between lithium and the trivalent transition-metal Carbodiimide Cr2(NCN)3, which shows excellent performance as a negative electrode material in Li-ion batteries, is conducted combining complementary operando analyses and state-of-the-art density functional theory (DFT) calculations. As predicted by DFT, and evidenced by operando X-ray diffraction and Cr K-edge absorption spectroscopy, a two-step reaction pathway involving two redox couples (Cr3þ/Cr2þ and Cr2þ/Cr0) and a concomitant formation of Cr metal nanoparticles is apparent, thus indicating that the conversion reaction of this Carbodiimide upon lithiation occurs only after a preliminary intercalation step involving two Li per unit formula. This mechanism, evidenced for the first time in transition-metal Carbodiimides, is likely behind its outstanding electrochemical performance as Cr2(NCN)3 can maintain more than 600 mAh g1 for 900 cycles at a high rate of 2 C.
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Electrochemical Evaluation of Pb, Ag, and Zn Cyanamides/Carbodiimides
ACS Omega, 2019Co-Authors: Jeethu Arayamparambil, Lorenzo Stievano, Richard Dronskowski, Markus Mann, Xiaohui Liu, Maria Alfredsson, Moulay Tahar SougratiAbstract:PbNCN, Ag 2 NCN, and ZnNCN were tested as negative electrode materials for Li-ion batteries. A thorough analysis of the electrochemical mechanism by X-ray diffraction and X-ray absorption spectroscopy showed that, unlike transition metal Carbodiimides, these compounds react with lithium via a two-step reaction, starting with conversion followed by alloying. The conversion reaction is highly irreversible for the three compounds, whereas the reversibility of the alloying reaction depends on the metal, that is, highly irreversible for PbNCN and Ag 2 NCN which contain the cyanamide group (NC−N 2−) and more reversible for ZnNCN containing Carbodiimide (− NCN −). In the case of the more covalent, cyanamide-type PbNCN and Ag 2 NCN, the conversion reaction occurs at a higher voltage compared to the more ionic, Carbodiimide-type ZnNCN, correlated with the nature of bonding in the NCN group and in the phases themselves. Compared to transition metal Carbodiimides, these materials show rather low performance, with no improvement in capacity as it would have been expected from the combination of conversion and alloying.
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METAL CarbodiimideS AND METAL CYANAMIDES AS ELECTRODE MATERIALS
2016Co-Authors: Moulay Tahar Sougrati, Raphaël Pierre Hermann, Markus Herlitschke, Mahmoud Abdelfattah, Laure Monconduit, Lorenzo Stievano, Richard DronskowskiAbstract:(EN)The invention relates to the use of a metal Carbodiimide or a metal cyanamide as a new active material for a negative electrode, a negative electrode comprising said metal Carbodiimide or metal cyanamide, its preparation method, a battery comprising said negative electrode, and a method for the preparation of a composite material. (FR)L'invention concerne l'utilisation d'un Carbodiimide métallique ou d'un cyanamide métallique en tant que nouveau matériau actif pour une électrode négative, une électrode négative comprenant ce Carbodiimide métallique ou ce cyanamide métallique, son procédé de préparation, une batterie comprenant l'électrode négative, et un procédé pour la préparation d'un matériau composite.
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transition metal Carbodiimides as molecular negative electrode materials for lithium and sodium ion batteries with excellent cycling properties
Angewandte Chemie, 2016Co-Authors: Moulay Tahar Sougrati, Raphaël Pierre Hermann, Ali Darwiche, Abdelfattah Mahmoud, Samuel Jouen, Laure Monconduit, Richard Dronskowski, Lorenzo StievanoAbstract:We report evidence for the electrochemical activity of transition-metal Carbodiimides versus lithium and sodium. In particular, iron Carbodiimide, FeNCN, can be efficiently used as negative electrode material for alkali-metal-ion batteries, similar to its oxide analogue FeO. Based on 57Fe Mossbauer and infrared spectroscopy (IR) data, the electrochemical reaction mechanism can be explained by the reversible transformation of the Fe−NCN into Li/Na−NCN bonds during discharge and charge. These new electrode materials exhibit higher capacity compared to well-established negative electrode references such as graphite or hard carbon. Contrary to its oxide analogue, iron Carbodiimide does not require heavy treatments (such as nanoscale tailoring, sophisticated textures, or coating) to obtain long cycle life with current density as high as 9 A g−1 for hundreds of charge–discharge cycles. Similar to the iron compound, several other transition-metal Carbodiimides Mx(NCN)y with M=Mn, Cr, Zn can cycle successfully versus lithium and sodium. Their electrochemical activity and performance open the way to the design of a novel family of anode materials.
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Transition‐Metal Carbodiimides as Molecular Negative Electrode Materials for Lithium‐ and Sodium‐Ion Batteries with Excellent Cycling Properties
Angewandte Chemie, 2016Co-Authors: Moulay Tahar Sougrati, Mahmoud Abdelfattah, Samuel Jouen, Laure Monconduit, Richard Dronskowski, Darwiche Ali, Xiaohiu Liu, Raphaël P. Hermann, Lorenzo StievanoAbstract:We report evidence for the electrochemical activity of transition‐metal Carbodiimides versus lithium and sodium. In particular, iron Carbodiimide, FeNCN, can be efficiently used as negative electrode material for alkali‐metal‐ion batteries, similar to its oxide analogue FeO. Based on 57Fe Mössbauer and infrared spectroscopy (IR) data, the electrochemical reaction mechanism can be explained by the reversible transformation of the Fe−NCN into Li/Na−NCN bonds during discharge and charge. These new electrode materials exhibit higher capacity compared to well‐established negative electrode references such as graphite or hard carbon. Contrary to its oxide analogue, iron Carbodiimide does not require heavy treatments (such as nanoscale tailoring, sophisticated textures, or coating) to obtain long cycle life with current density as high as 9 A g−1 for hundreds of charge–discharge cycles. Similar to the iron compound, several other transition‐metal Carbodiimides Mx(NCN)y with M=Mn, Cr, Zn can cycle successfully versus lithium and sodium. Their electrochemical activity and performance open the way to the design of a novel family of anode materials.
C. S Osborne - One of the best experts on this subject based on the ideXlab platform.
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Investigation into the biological stability of collagen/chondroitin-6-sulphate gels and their contraction by fibroblasts and keratinocytes : The effect of crosslinking agents and diamines
Biomaterials, 1999Co-Authors: C. S Osborne, W. H Reid, M.h. GrantAbstract:Abstract Artificial skin substitutes based on autologous keratinocytes cultured on collagen-based substrata are being developed for grafting onto patients with severe burns. The properties of the substratum can be manipulated by crosslinking the collagen with the glysocaminoglycan, chondroitin-6-sulphate (Ch6SO 4 ), Carbodiimides and polyamines. Biological stability, assessed by resistance to collagenase, was increased by incorporation of Ch6SO 4 , but crosslinking with the Carbodiimides, 1-ethyl-3-(dimethylamino-propyl)Carbodiimide and 1,1-carbonyldiimidazole or the polyamines, putrescine or diaminohexane, had little further benefit. Contraction of the collagen gels occurred to a greater extent when seeded with fibroblasts than with keratinocytes. The extent of contraction by either cell type was not influenced by the presence of Ch6SO 4 in the gel, but the Carbodiimides, and to a lesser extent the polyamines, limited cell-mediated contraction, particularly that mediated by fibroblasts. Optimum substratum composition for artificial skin substitutes will involve a compromise between the desired attributes of biological stability, rate of contraction, mechanical strength, biocompatibility and promotion of cell growth.
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Investigation into cell growth on collagen/chondroitin-6-sulphate gels: the effect of crosslinking agents and diamines
Journal of Materials Science: Materials in Medicine, 1997Co-Authors: C. S Osborne, W. H Reid, M.h. GrantAbstract:Artificial skin substitutes based on cultured autologous keratinocytes need to have sufficient strength and ease of handling to be utilized successfully by surgeons in the clinic. This may be achieved by crosslinking the collagen substratum on which the cells are cultured, which in this case is a collagen gel. Increased strength must be attained without detrimental effect on cell growth. The influence of potential crosslinking agents including the glycosaminoglycan, chondroitin-6-sulphate (Ch6SO4), the water soluble Carbodiimide crosslinking agents 1-ethyl-3-(3-diaminopropyl) Carbodiimide (EDAC), and 1,1-carbonyldiimidazole (CDI), and the polyamines putrescine, spermine and diaminohexane, on cell growth rate has been investigated. Incorporation of 20% Ch6SO4 into collagen gels caused an approximately 16% increase in keratinocyte growth, but had no significant effect on that of dermal fibroblasts. Pre-formed collagen gels (+/− Ch6SO4) were treated with the Carbodiimides. This crosslinking treatment markedly inhibited fibroblast growth (EDAC 45% inhibition, CDI 70%), without affecting that of keratinocytes. Pre-formed collagen gels (+/−Ch6SO4 and Carbodiimide) were treated with 0.1 M, 0.5 M or 1.0 M polyamine. Spermine inhibited the growth rate of both cell types at all concentrations tested, whereas putrescine and diaminohexane had little effect. The mechanical strength of these crosslinked gels is currently being assessed to determine the optimum composition in terms of cell growth and biocompatibility, and strength.
W. H Reid - One of the best experts on this subject based on the ideXlab platform.
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Investigation into the biological stability of collagen/chondroitin-6-sulphate gels and their contraction by fibroblasts and keratinocytes : The effect of crosslinking agents and diamines
Biomaterials, 1999Co-Authors: C. S Osborne, W. H Reid, M.h. GrantAbstract:Abstract Artificial skin substitutes based on autologous keratinocytes cultured on collagen-based substrata are being developed for grafting onto patients with severe burns. The properties of the substratum can be manipulated by crosslinking the collagen with the glysocaminoglycan, chondroitin-6-sulphate (Ch6SO 4 ), Carbodiimides and polyamines. Biological stability, assessed by resistance to collagenase, was increased by incorporation of Ch6SO 4 , but crosslinking with the Carbodiimides, 1-ethyl-3-(dimethylamino-propyl)Carbodiimide and 1,1-carbonyldiimidazole or the polyamines, putrescine or diaminohexane, had little further benefit. Contraction of the collagen gels occurred to a greater extent when seeded with fibroblasts than with keratinocytes. The extent of contraction by either cell type was not influenced by the presence of Ch6SO 4 in the gel, but the Carbodiimides, and to a lesser extent the polyamines, limited cell-mediated contraction, particularly that mediated by fibroblasts. Optimum substratum composition for artificial skin substitutes will involve a compromise between the desired attributes of biological stability, rate of contraction, mechanical strength, biocompatibility and promotion of cell growth.
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Investigation into cell growth on collagen/chondroitin-6-sulphate gels: the effect of crosslinking agents and diamines
Journal of Materials Science: Materials in Medicine, 1997Co-Authors: C. S Osborne, W. H Reid, M.h. GrantAbstract:Artificial skin substitutes based on cultured autologous keratinocytes need to have sufficient strength and ease of handling to be utilized successfully by surgeons in the clinic. This may be achieved by crosslinking the collagen substratum on which the cells are cultured, which in this case is a collagen gel. Increased strength must be attained without detrimental effect on cell growth. The influence of potential crosslinking agents including the glycosaminoglycan, chondroitin-6-sulphate (Ch6SO4), the water soluble Carbodiimide crosslinking agents 1-ethyl-3-(3-diaminopropyl) Carbodiimide (EDAC), and 1,1-carbonyldiimidazole (CDI), and the polyamines putrescine, spermine and diaminohexane, on cell growth rate has been investigated. Incorporation of 20% Ch6SO4 into collagen gels caused an approximately 16% increase in keratinocyte growth, but had no significant effect on that of dermal fibroblasts. Pre-formed collagen gels (+/− Ch6SO4) were treated with the Carbodiimides. This crosslinking treatment markedly inhibited fibroblast growth (EDAC 45% inhibition, CDI 70%), without affecting that of keratinocytes. Pre-formed collagen gels (+/−Ch6SO4 and Carbodiimide) were treated with 0.1 M, 0.5 M or 1.0 M polyamine. Spermine inhibited the growth rate of both cell types at all concentrations tested, whereas putrescine and diaminohexane had little effect. The mechanical strength of these crosslinked gels is currently being assessed to determine the optimum composition in terms of cell growth and biocompatibility, and strength.
Moulay Tahar Sougrati - One of the best experts on this subject based on the ideXlab platform.
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Reversible High Capacity and Reaction Mechanism of Cr 2 (NCN) 3 Negative Electrodes for Li‐Ion Batteries
Energy Technology, 2020Co-Authors: Jeethu Jiju Arayamparambil, Moulay Tahar Sougrati, Richard Dronskowski, Jeethu Arayamparambil, Markus Mann, Kaixuan Chen, Antonella Iadecola, Xianji Qiao, Bernard Fraisse, Lorenzo StievanoAbstract:A detailed study of the electrochemical reaction mechanism between lithium and the trivalent transition-metal Carbodiimide Cr2(NCN)3, which shows excellent performance as a negative electrode material in Li-ion batteries, is conducted combining complementary operando analyses and state-of-the-art density functional theory (DFT) calculations. As predicted by DFT, and evidenced by operando X-ray diffraction and Cr K-edge absorption spectroscopy, a two-step reaction pathway involving two redox couples (Cr3þ/Cr2þ and Cr2þ/Cr0) and a concomitant formation of Cr metal nanoparticles is apparent, thus indicating that the conversion reaction of this Carbodiimide upon lithiation occurs only after a preliminary intercalation step involving two Li per unit formula. This mechanism, evidenced for the first time in transition-metal Carbodiimides, is likely behind its outstanding electrochemical performance as Cr2(NCN)3 can maintain more than 600 mAh g1 for 900 cycles at a high rate of 2 C.
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Electrochemical Evaluation of Pb, Ag, and Zn Cyanamides/Carbodiimides
ACS Omega, 2019Co-Authors: Jeethu Arayamparambil, Lorenzo Stievano, Richard Dronskowski, Markus Mann, Xiaohui Liu, Maria Alfredsson, Moulay Tahar SougratiAbstract:PbNCN, Ag 2 NCN, and ZnNCN were tested as negative electrode materials for Li-ion batteries. A thorough analysis of the electrochemical mechanism by X-ray diffraction and X-ray absorption spectroscopy showed that, unlike transition metal Carbodiimides, these compounds react with lithium via a two-step reaction, starting with conversion followed by alloying. The conversion reaction is highly irreversible for the three compounds, whereas the reversibility of the alloying reaction depends on the metal, that is, highly irreversible for PbNCN and Ag 2 NCN which contain the cyanamide group (NC−N 2−) and more reversible for ZnNCN containing Carbodiimide (− NCN −). In the case of the more covalent, cyanamide-type PbNCN and Ag 2 NCN, the conversion reaction occurs at a higher voltage compared to the more ionic, Carbodiimide-type ZnNCN, correlated with the nature of bonding in the NCN group and in the phases themselves. Compared to transition metal Carbodiimides, these materials show rather low performance, with no improvement in capacity as it would have been expected from the combination of conversion and alloying.
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METAL CarbodiimideS AND METAL CYANAMIDES AS ELECTRODE MATERIALS
2016Co-Authors: Moulay Tahar Sougrati, Raphaël Pierre Hermann, Markus Herlitschke, Mahmoud Abdelfattah, Laure Monconduit, Lorenzo Stievano, Richard DronskowskiAbstract:(EN)The invention relates to the use of a metal Carbodiimide or a metal cyanamide as a new active material for a negative electrode, a negative electrode comprising said metal Carbodiimide or metal cyanamide, its preparation method, a battery comprising said negative electrode, and a method for the preparation of a composite material. (FR)L'invention concerne l'utilisation d'un Carbodiimide métallique ou d'un cyanamide métallique en tant que nouveau matériau actif pour une électrode négative, une électrode négative comprenant ce Carbodiimide métallique ou ce cyanamide métallique, son procédé de préparation, une batterie comprenant l'électrode négative, et un procédé pour la préparation d'un matériau composite.
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transition metal Carbodiimides as molecular negative electrode materials for lithium and sodium ion batteries with excellent cycling properties
Angewandte Chemie, 2016Co-Authors: Moulay Tahar Sougrati, Raphaël Pierre Hermann, Ali Darwiche, Abdelfattah Mahmoud, Samuel Jouen, Laure Monconduit, Richard Dronskowski, Lorenzo StievanoAbstract:We report evidence for the electrochemical activity of transition-metal Carbodiimides versus lithium and sodium. In particular, iron Carbodiimide, FeNCN, can be efficiently used as negative electrode material for alkali-metal-ion batteries, similar to its oxide analogue FeO. Based on 57Fe Mossbauer and infrared spectroscopy (IR) data, the electrochemical reaction mechanism can be explained by the reversible transformation of the Fe−NCN into Li/Na−NCN bonds during discharge and charge. These new electrode materials exhibit higher capacity compared to well-established negative electrode references such as graphite or hard carbon. Contrary to its oxide analogue, iron Carbodiimide does not require heavy treatments (such as nanoscale tailoring, sophisticated textures, or coating) to obtain long cycle life with current density as high as 9 A g−1 for hundreds of charge–discharge cycles. Similar to the iron compound, several other transition-metal Carbodiimides Mx(NCN)y with M=Mn, Cr, Zn can cycle successfully versus lithium and sodium. Their electrochemical activity and performance open the way to the design of a novel family of anode materials.
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Transition‐Metal Carbodiimides as Molecular Negative Electrode Materials for Lithium‐ and Sodium‐Ion Batteries with Excellent Cycling Properties
Angewandte Chemie, 2016Co-Authors: Moulay Tahar Sougrati, Mahmoud Abdelfattah, Samuel Jouen, Laure Monconduit, Richard Dronskowski, Darwiche Ali, Xiaohiu Liu, Raphaël P. Hermann, Lorenzo StievanoAbstract:We report evidence for the electrochemical activity of transition‐metal Carbodiimides versus lithium and sodium. In particular, iron Carbodiimide, FeNCN, can be efficiently used as negative electrode material for alkali‐metal‐ion batteries, similar to its oxide analogue FeO. Based on 57Fe Mössbauer and infrared spectroscopy (IR) data, the electrochemical reaction mechanism can be explained by the reversible transformation of the Fe−NCN into Li/Na−NCN bonds during discharge and charge. These new electrode materials exhibit higher capacity compared to well‐established negative electrode references such as graphite or hard carbon. Contrary to its oxide analogue, iron Carbodiimide does not require heavy treatments (such as nanoscale tailoring, sophisticated textures, or coating) to obtain long cycle life with current density as high as 9 A g−1 for hundreds of charge–discharge cycles. Similar to the iron compound, several other transition‐metal Carbodiimides Mx(NCN)y with M=Mn, Cr, Zn can cycle successfully versus lithium and sodium. Their electrochemical activity and performance open the way to the design of a novel family of anode materials.