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6 results on '"Gunma University. Graduate School of Engineering"'

1. Hydrogen storage in CO2-activated amorphous nanofibers and their monoliths

Author

Universidad de Alicante. Departamento de Química Inorgánica, Gunma University. Graduate School of Engineering, Kunowsky, Mirko, Marco Lozar, Juan Pablo, Oya, Asao, Linares-Solano, Angel, Universidad de Alicante. Departamento de Química Inorgánica, Gunma University. Graduate School of Engineering, Kunowsky, Mirko, Marco Lozar, Juan Pablo, Oya, Asao, and Linares-Solano, Angel

Abstract

Amorphous carbon nanofibers (CNFs), produced by the polymer blend technique, are activated by CO2 (ACNFs). Monoliths are synthesized from the precursor and from some ACNFs. Morphology and textural properties of these materials are studied. When compared with other activating agents (steam and alkaline hydroxides), CO2 activation renders suitable yields and, contrarily to most other precursors, turns out to be advantageous for developing and controlling their narrow microporosity (< 0.7 nm), VDR(CO2). The obtained ACNFs have a high compressibility and, consequently, a high packing density under mechanical pressure which can also be maintained upon monolith synthesis. H2 adsorption is measured at two different conditions (77 K / 0.11 MPa, and 298 K / 20 MPa) and compared with other activated carbons. Under both conditions, H2 uptake depends on the narrow microporosity of the prepared ACNFs. Interestingly, at room temperature these ACNFs perform better than other activated carbons, despite their lower porosity developments. At 298 K they reach a H2 adsorption capacity as high as 1.3 wt.%, and a remarkable value of 1 wt.% in its mechanically resistant monolith form.

Published
2011

2. Activation of polymer blend carbon nanofibres by alkaline hydroxides and their hydrogen storage performances

Author

Universidad de Alicante. Departamento de Química Inorgánica, Gun Ei Chemical Ind. Co., Gunma University. Graduate School of Engineering, Suárez García, Fabián, Vilaplana-Ortego, Eduardo, Kunowsky, Mirko, Kimura, M., Oya, Asao, Linares-Solano, Angel, Universidad de Alicante. Departamento de Química Inorgánica, Gun Ei Chemical Ind. Co., Gunma University. Graduate School of Engineering, Suárez García, Fabián, Vilaplana-Ortego, Eduardo, Kunowsky, Mirko, Kimura, M., Oya, Asao, and Linares-Solano, Angel

Abstract

In the present work we study the hydroxide activation (NaOH and KOH) of phenol-formaldehyde resin derived CNFs prepared by a polymer blend technique to prepare highly porous activated carbon nanofibres (ACNFs). Morphology and textural characteristics of these ACNFs were studied and their hydrogen storage capacities at 77 K (at 0.1 MPa and at high pressures up to 4 MPa) were assessed, and compared, with reported capacities of other porous carbon materials. Phenol-formaldehyde resin derived carbon fibres were successfully activated with these two alkaline hydroxides rendering highly microporous ACNFs with reasonable good activation process yields up to 47 wt.% compared to 7 wt.% yields from steam activation for similar surface areas of 1500 m2/g or higher. These nano-sized activated carbons present interesting H2 storage capacities at 77 K which are comparable, or even higher, to other high quality microporous carbon materials. This observation is due, in part, to their nano-sized diameters allowing to enhance their packing densities to 0.71 g/cm3 and hence their resulting hydrogen storage capacities.

Published
2009

3. Hydrogen storage in CO2-activated amorphous nanofibers and their monoliths

Author

Asao Oya, J.P. Marco-Lozar, A. Linares-Solano, Mirko Kunowsky, Universidad de Alicante. Departamento de Química Inorgánica, Gunma University. Graduate School of Engineering, and Materiales Carbonosos y Medio Ambiente

Subjects
Química Inorgánica, geography, Materials science, geography.geographical_feature_category, Ciencia de los Materiales e Ingeniería Metalúrgica, General Chemistry, Hydrogen storage, Hydrogen adsorption, Amorphous solid, Carbon dioxide, Nanofiber, Physical activation, Carbon nanofibre, General Materials Science, Monolith, Composite material, Tecnologías del Medio Ambiente
Abstract

Amorphous carbon nanofibers (CNFs), produced by the polymer blend technique, are activated by CO2 (ACNFs). Monoliths are synthesized from the precursor and from some ACNFs. Morphology and textural properties of these materials are studied. When compared with other activating agents (steam and alkaline hydroxides), CO2 activation renders suitable yields and, contrarily to most other precursors, turns out to be advantageous for developing and controlling their narrow microporosity (< 0.7 nm), VDR(CO2). The obtained ACNFs have a high compressibility and, consequently, a high packing density under mechanical pressure which can also be maintained upon monolith synthesis. H2 adsorption is measured at two different conditions (77 K / 0.11 MPa, and 298 K / 20 MPa) and compared with other activated carbons. Under both conditions, H2 uptake depends on the narrow microporosity of the prepared ACNFs. Interestingly, at room temperature these ACNFs perform better than other activated carbons, despite their lower porosity developments. At 298 K they reach a H2 adsorption capacity as high as 1.3 wt.%, and a remarkable value of 1 wt.% in its mechanically resistant monolith form. Spanish MICINN (Project MAT2009-07150) and Generalitat Valenciana and FEDER (Project PROMETEO/2009/047).

Published
2012
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4. Activation of polymer blend carbon nanofibres by alkaline hydroxides and their hydrogen storage performances

Author

M. Kimura, Mirko Kunowsky, Asao Oya, Angel Linares-Solano, Eduardo Vilaplana-Ortego, F. Suárez-García, Universidad de Alicante. Departamento de Química Inorgánica, Gun Ei Chemical Ind. Co., Gunma University. Graduate School of Engineering, and Materiales Carbonosos y Medio Ambiente

Subjects
Química Inorgánica, Materials science, Morphology (linguistics), Renewable Energy, Sustainability and the Environment, Carbon nanofiber, Packing density, Ciencia de los Materiales e Ingeniería Metalúrgica, Formaldehyde, Energy Engineering and Power Technology, Carbon nanofibres, Hydrogen storage, Condensed Matter Physics, Chemical activation, chemistry.chemical_compound, Fuel Technology, chemistry, Chemical engineering, Nanofiber, Polymer chemistry, medicine, Polymer blend, Water vapor, Activated carbon, medicine.drug
Abstract

In the present work we study the hydroxide activation (NaOH and KOH) of phenol-formaldehyde resin derived CNFs prepared by a polymer blend technique to prepare highly porous activated carbon nanofibres (ACNFs). Morphology and textural characteristics of these ACNFs were studied and their hydrogen storage capacities at 77 K (at 0.1 MPa and at high pressures up to 4 MPa) were assessed, and compared, with reported capacities of other porous carbon materials. Phenol-formaldehyde resin derived carbon fibres were successfully activated with these two alkaline hydroxides rendering highly microporous ACNFs with reasonable good activation process yields up to 47 wt.% compared to 7 wt.% yields from steam activation for similar surface areas of 1500 m2/g or higher. These nano-sized activated carbons present interesting H2 storage capacities at 77 K which are comparable, or even higher, to other high quality microporous carbon materials. This observation is due, in part, to their nano-sized diameters allowing to enhance their packing densities to 0.71 g/cm3 and hence their resulting hydrogen storage capacities. MEC (Acción complementaria; ENE2005-23824-E/CON), Generalitat Valenciana (Acción complementaria; ACOMP06/089), MICINN (Project CTQ2006-08958/PPQ).

Published
2009

5. An abdominal spacer that does not require surgical removal and allows drainage of abdominal fluids in patients undergoing carbon ion radiotherapy.

Author

Kubo N, Yokobori T, Takahashi R, Ogawa H, Gombodorj N, Ohta N, Ohno T, Saeki H, Shirabe K, and Asao T

Subjects
Abdomen physiopathology, Abdominal Neoplasms surgery, Animals, Drainage instrumentation, Swine, Abdominal Neoplasms radiotherapy, Catheters, Drainage methods, Heavy Ion Radiotherapy methods
Abstract

Abdominal spacers are useful for maintaining the distance between the target tumors and surrounding tissues, such as the gastrointestinal tract, in patients treated with carbon ion radiotherapy. Surgical intervention to remove the spacers is sometimes necessary because of abdominal infections triggered by long-term spacer placement or intestinal perforation. Therefore, spacers that do not require surgical removal and provide effective drainage against abdominal infections are urgently needed. This study aimed to develop a spacer that could be removed non-surgically and one that provides the therapeutic effect of drainage in patients who receive carbon ion radiotherapy for abdominal tumors. A novel fan-shaped spacer was constructed from a film drain that was folded along the trigger line. Simple withdrawal of the trigger line caused the film drain to fold and the holding lines to become free. We performed laparoscopy-assisted insertion with pneumoperitoneum and blind removal of the spacer fourteen times using a porcine model. Saline in the abdominal cavity was effectively aspirated using the spacer. Our novel fan-shaped spacer could be removed safely without surgery and was able to drain fluid effectively from the abdominal cavity., Competing Interests: The authors have declared that no competing interests exist.

Published
2020
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6. 5-Oxo-eicosatetraenoic acid-induced chemotaxis: identification of a responsible receptor hGPCR48 and negative regulation by G protein G(12/13).

Author

Koike D, Obinata H, Yamamoto A, Takeda S, Komori H, Nara F, Izumi T, and Haga T

Subjects
Animals, CHO Cells, Cells, Cultured, Cricetinae, Cricetulus, Down-Regulation physiology, Humans, Receptors, G-Protein-Coupled antagonists & inhibitors, Arachidonic Acids physiology, Chemotaxis physiology, GTP-Binding Proteins physiology, Receptors, G-Protein-Coupled physiology
Abstract

While screening genes encoding G protein-coupled receptors (GPCRs) in the human genome, we and other groups have identified a GPCR named hGPCR48 as a high affinity receptor for 5-oxo-6,8,11,14-eicosatetraenoic acid (5-oxo-ETE), which is arachidonic acid metabolite and an endogenous chemoattractant for granulocytes. Using Chinese hamster ovary (CHO) cells stably expressing hGPCR48, we show here that activation of the receptor causes the chemotaxis of the cells toward 5-oxo-ETE. We also show that the chemotaxis of human granulocytes toward 5-oxo-ETE is inhibited by pretreatment with anti-hGPCR48 antibodies, indicating that hGPCR48 is an endogenous receptor responsible for chemotaxis of granulocytes toward 5-oxo-ETE. In addition, we show that the chemotaxis of CHO cells expressing hGPCR48 is suppressed by pretreatment with pertussis toxin, and enhanced by overexpression of the carboxy terminal peptides of Galpha (12/13) subunits or a regulator of the G protein signaling domain of p115RhoGEF, both of which are known to suppress G(12/13)-dependent signaling pathways. These results indicate that hGPCR48 couples with G(i/o) and G(12/13) proteins, which then initiate or attenuate the chemotaxis of the cells toward 5-oxo-ETE, respectively.

Published
2006
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