Documents disponibles écrits par cet auteur

Assessment of the antifouling properties of polyzwitterions from free energy calculations by molecular dynamics simulations / Ryo Nagumo in Industrial & engineering chemistry research, Vol. 51 N° 11 (Mars 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 11 (Mars 2012) . - pp. 4458-4462 Titre : Assessment of the antifouling properties of polyzwitterions from free energy calculations by molecular dynamics simulations Type de document : texte imprimé Auteurs : Ryo Nagumo, Auteur ; Kazuki Akamatsu, Auteur ; Ryuji Miura, Auteur Année de publication : 2012 Article en page(s) : pp. 4458-4462 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermodynamic  properties  Modeling  Dynamic  model  Molecular  dynamics  method  Free  energy Résumé : Polyzwitterions (PZs), such as carboxybetaine and phosphobetaine polymers, show remarkable suppression of protein adsorption and have potentially widespread application as bioengineering materials. We show that free energy profiles, from molecular dynamics simulations in explicit water, for hydrophilic and hydrophobic amino acids approaching a PZ monomer, provide thermodynamic insights into protein adsorption. The predicted profiles for PZ have almost no energetically stable points, regardless of the type of residue. In contrast, the profiles for conventional polyester show some energetically remarkable minima, particularly for the hydrophobic residue. These results agree with recent experimental reports of differences in the amounts of protein adsorbed on these polymers, suggesting that free energy calculations for hydrophobic residue can play a sigitificant role in assessing antifouling properties. Our simple strategy, which investigates the affinities between residues and monomers, can become a convenient approach to predicting protein antifouling properties of polymeric materials. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25655655 [article] Assessment of the antifouling properties of polyzwitterions from free energy calculations by molecular dynamics simulations [texte imprimé] / Ryo Nagumo, Auteur ; Kazuki Akamatsu, Auteur ; Ryuji Miura, Auteur . - 2012 . - pp. 4458-4462. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 11 (Mars 2012) . - pp. 4458-4462 Mots-clés : Thermodynamic  properties  Modeling  Dynamic  model  Molecular  dynamics  method  Free  energy Résumé : Polyzwitterions (PZs), such as carboxybetaine and phosphobetaine polymers, show remarkable suppression of protein adsorption and have potentially widespread application as bioengineering materials. We show that free energy profiles, from molecular dynamics simulations in explicit water, for hydrophilic and hydrophobic amino acids approaching a PZ monomer, provide thermodynamic insights into protein adsorption. The predicted profiles for PZ have almost no energetically stable points, regardless of the type of residue. In contrast, the profiles for conventional polyester show some energetically remarkable minima, particularly for the hydrophobic residue. These results agree with recent experimental reports of differences in the amounts of protein adsorbed on these polymers, suggesting that free energy calculations for hydrophobic residue can play a sigitificant role in assessing antifouling properties. Our simple strategy, which investigates the affinities between residues and monomers, can become a convenient approach to predicting protein antifouling properties of polymeric materials. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25655655

Dehydrogenation of methylcyclohexane to produce high - purity hydrogen using membrane reactors with amorphous silica membranes / Kazunori Oda in Industrial & engineering chemistry research, Vol. 49 N° 22 (Novembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 22 (Novembre 2010) . - pp. 11287-11293 Titre : Dehydrogenation of methylcyclohexane to produce high - purity hydrogen using membrane reactors with amorphous silica membranes Type de document : texte imprimé Auteurs : Kazunori Oda, Auteur ; Kazuki Akamatsu, Auteur ; Takashi Sugawara, Auteur Année de publication : 2011 Article en page(s) : pp. 11287-11293 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Membrane  reactor  High  purity  Dehydrogenation Résumé : We developed a membrane reactor that can produce high-purity hydrogen in one step from methylcyclohexane. This membrane reactor combined a hydrogen-selective amorphous silica membrane prepared with dimethoxy-diphenylsilane and oxygen and employing counter-diffusion chemical vapor deposition, and Pt/Al2O3 catalyst. The silica membrane showed excellent hydrogen permeance at 573 K of the order of 10-5 mol m-2 s-1Pa-1 and high hydrogen/sulfur hexafluoride permselectivity of around 104. The membrane reactor exhibited equilibrium shifts as expected under reaction temperatures ranging from 473 to 553 K and reaction pressures ranging from 0.1 to 0.25 MPa, and these performances were successfully predicted using a simulation model, which was also developed in this study. Finally, we demonstrated that hydrogen with purity as high as 99.95% was produced from methylcyclohexane in the membrane reactor without using carrier gas or sweep gas. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101210x [article] Dehydrogenation of methylcyclohexane to produce high - purity hydrogen using membrane reactors with amorphous silica membranes [texte imprimé] / Kazunori Oda, Auteur ; Kazuki Akamatsu, Auteur ; Takashi Sugawara, Auteur . - 2011 . - pp. 11287-11293. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 22 (Novembre 2010) . - pp. 11287-11293 Mots-clés : Membrane  reactor  High  purity  Dehydrogenation Résumé : We developed a membrane reactor that can produce high-purity hydrogen in one step from methylcyclohexane. This membrane reactor combined a hydrogen-selective amorphous silica membrane prepared with dimethoxy-diphenylsilane and oxygen and employing counter-diffusion chemical vapor deposition, and Pt/Al2O3 catalyst. The silica membrane showed excellent hydrogen permeance at 573 K of the order of 10-5 mol m-2 s-1Pa-1 and high hydrogen/sulfur hexafluoride permselectivity of around 104. The membrane reactor exhibited equilibrium shifts as expected under reaction temperatures ranging from 473 to 553 K and reaction pressures ranging from 0.1 to 0.25 MPa, and these performances were successfully predicted using a simulation model, which was also developed in this study. Finally, we demonstrated that hydrogen with purity as high as 99.95% was produced from methylcyclohexane in the membrane reactor without using carrier gas or sweep gas. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101210x

Fouling - free membranes obtained by facile surface modification of commercially available membranes using the dynamic forming method / Kazuki Akamatsu in Industrial & engineering chemistry research, Vol. 50 N° 21 (Novembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 21 (Novembre 2011) . - pp. 12281-12284 Titre : Fouling - free membranes obtained by facile surface modification of commercially available membranes using the dynamic forming method Type de document : texte imprimé Auteurs : Kazuki Akamatsu, Auteur ; Keita Mitsumori, Auteur ; Fang Han, Auteur Année de publication : 2011 Article en page(s) : pp. 12281-12284 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fouling Résumé : The dynamic forming method was first employed for the preparation of fouling-free membranes. The copolymer of 1-carboxy-N,N-dimethyl-N-(2'-methacryloyloxyethyl) methanaminium inner salt and n-butyl methacrylate was selected for the surface modification polymer to realize the fouling-free property in this study, and its aqueous solution was filtered using a commercially available ultrafiltration membrane. The surface modification polymer was thus deposited on the ultrafiltration membrane in a facile manner over several minutes. Compared to the unmodified membrane, the dynamically formed membrane with the surface modification polymer layer proved to have excellent fouling resistance against 1000 ppm bovine serum albumin (BSA) solution. In particular, the dynamically formed membrane was hardly fouled and maintained its initial flux when the filtration flux was set below 6 × 10-6 m3 m-2 s-1. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24697548 [article] Fouling - free membranes obtained by facile surface modification of commercially available membranes using the dynamic forming method [texte imprimé] / Kazuki Akamatsu, Auteur ; Keita Mitsumori, Auteur ; Fang Han, Auteur . - 2011 . - pp. 12281-12284. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 21 (Novembre 2011) . - pp. 12281-12284 Mots-clés : Fouling Résumé : The dynamic forming method was first employed for the preparation of fouling-free membranes. The copolymer of 1-carboxy-N,N-dimethyl-N-(2'-methacryloyloxyethyl) methanaminium inner salt and n-butyl methacrylate was selected for the surface modification polymer to realize the fouling-free property in this study, and its aqueous solution was filtered using a commercially available ultrafiltration membrane. The surface modification polymer was thus deposited on the ultrafiltration membrane in a facile manner over several minutes. Compared to the unmodified membrane, the dynamically formed membrane with the surface modification polymer layer proved to have excellent fouling resistance against 1000 ppm bovine serum albumin (BSA) solution. In particular, the dynamically formed membrane was hardly fouled and maintained its initial flux when the filtration flux was set below 6 × 10-6 m3 m-2 s-1. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24697548

Three preparation methods for monodispersed chitosan microspheres using the shirasu porous glass membrane emulsification technique and mechanisms of microsphere formation / Kazuki Akamatsu in Industrial & engineering chemistry research, Vol. 49 N° 7 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3236–3241 Titre : Three preparation methods for monodispersed chitosan microspheres using the shirasu porous glass membrane emulsification technique and mechanisms of microsphere formation Type de document : texte imprimé Auteurs : Kazuki Akamatsu, Auteur ; Daisaku Kaneko, Auteur ; Takashi Sugawara, Auteur Année de publication : 2010 Article en page(s) : pp. 3236–3241 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Monodispersed  Chitosan  Microspheres  Shirasu  Porous  Glass  Membrane  Emulsification  Mechanisms  Microsphere Résumé : The Shirasu porous glass (SPG) membrane emulsification technique was employed for the preparation of monodispersed chitosan microspheres with the diameter controlled to be in the range from submicrometers to 10 μm. Three preparation methods were used in this study: (1) a cross-linking method with glutaraldehyde, (2) an interaction method with alginate, and (3) a drying-in-liquid method with aqueous sodium hydroxide medium. In every preparation method, various SPG membranes with different pore sizes were used for microsphere formation, and the fabrication mechanism for the microspheres was elucidated. It was successfully shown from these detailed investigations that the average diameters of the chitosan microspheres were controlled in the range of submicrometer to 10 μm by the pore sizes of the SPG membranes for preparing chitosan emulsions by method 1, alginate emulsions by method 2, or chitosan emulsions by method 3. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901821s [article] Three preparation methods for monodispersed chitosan microspheres using the shirasu porous glass membrane emulsification technique and mechanisms of microsphere formation [texte imprimé] / Kazuki Akamatsu, Auteur ; Daisaku Kaneko, Auteur ; Takashi Sugawara, Auteur . - 2010 . - pp. 3236–3241. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3236–3241 Mots-clés : Monodispersed  Chitosan  Microspheres  Shirasu  Porous  Glass  Membrane  Emulsification  Mechanisms  Microsphere Résumé : The Shirasu porous glass (SPG) membrane emulsification technique was employed for the preparation of monodispersed chitosan microspheres with the diameter controlled to be in the range from submicrometers to 10 μm. Three preparation methods were used in this study: (1) a cross-linking method with glutaraldehyde, (2) an interaction method with alginate, and (3) a drying-in-liquid method with aqueous sodium hydroxide medium. In every preparation method, various SPG membranes with different pore sizes were used for microsphere formation, and the fabrication mechanism for the microspheres was elucidated. It was successfully shown from these detailed investigations that the average diameters of the chitosan microspheres were controlled in the range of submicrometer to 10 μm by the pore sizes of the SPG membranes for preparing chitosan emulsions by method 1, alginate emulsions by method 2, or chitosan emulsions by method 3. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901821s