Abnormally high pressure or temperature can significantly reduce the lifetime of atomic nuclei including stable. A hypothesis on stable nuclei decays caused by mechanical collision of macro-objects containing these nuclei is put forward. Mechanisms of such decays are presented. At the same time the distance between interacting nuclei can be significantly higher than the range of nuclear interaction (as manifestations of strong interaction). In decays initiated by external impact, the mean lifetime with respect to particular decay can change depending on these factors. The hypothesis is verified experimentally. When a bismuth bullet collides with a steel flat target, we see different types of stable bismuth isotope decay including cluster one, which is not found in nature (if there is no external impacts). This new class of physical processes can be related to the collective radioactive decay of atomic nuclei initiated by an external mechanical impact.
{"title":"The Collective Radioactive Decay of Atomic Nuclei Initiated by an External Mechanical Impact: Science Fiction or a New Class of Physical Processes","authors":"M. K. Marakhtanov, V. Okunev","doi":"10.5539/JMSR.V7N2P34","DOIUrl":"https://doi.org/10.5539/JMSR.V7N2P34","url":null,"abstract":"Abnormally high pressure or temperature can significantly reduce the lifetime of atomic nuclei including stable. A hypothesis on stable nuclei decays caused by mechanical collision of macro-objects containing these nuclei is put forward. Mechanisms of such decays are presented. At the same time the distance between interacting nuclei can be significantly higher than the range of nuclear interaction (as manifestations of strong interaction). In decays initiated by external impact, the mean lifetime with respect to particular decay can change depending on these factors. The hypothesis is verified experimentally. When a bismuth bullet collides with a steel flat target, we see different types of stable bismuth isotope decay including cluster one, which is not found in nature (if there is no external impacts). This new class of physical processes can be related to the collective radioactive decay of atomic nuclei initiated by an external mechanical impact.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"1 1","pages":"34"},"PeriodicalIF":0.0,"publicationDate":"2018-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87903634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chitosan nanocomposite thin films were fabricated using two types of chitosan natural polymer (cross-linked chitosan (CLCS) and non-cross-linked chitosan (NCLCS)), with three different weight percentages nano-fillers (Graphene (G) and fullerene (F)). Nanoindentation tests were performed to investigate the local mechanical properties of the produced nanocomposite in comparison to the unreinforced chitosan thin films. Nano hardness values (H) and indentation modulus (E) were measured using 5 and 10 µm spherical indenters. The addition of nano fillers enhanced the hardness of both types of films with the amount of hardening being directly proportional to the fraction of nano filler added(p<0.001). Crosslinking has also significantly increased the hardness (p< 0.001). The larger indentation returned a lower hardness. The use of different radii nano indenters underlined the indenter size effect due to the differing strain fields. The promising mechanical properties resulting from this research will allow using the fabricated nanocomposites for tissue engineering, biomedicine, drug delivery, electronics, energy, surface coatings and packaging applications.
{"title":"Nanoindentation Investigation on Chitosan Thin Films with Different Types of Nano Fillers","authors":"I. Fahim, N. Aboulkhair, N. Everitt","doi":"10.5539/JMSR.V7N2P11","DOIUrl":"https://doi.org/10.5539/JMSR.V7N2P11","url":null,"abstract":"Chitosan nanocomposite thin films were fabricated using two types of chitosan natural polymer (cross-linked chitosan (CLCS) and non-cross-linked chitosan (NCLCS)), with three different weight percentages nano-fillers (Graphene (G) and fullerene (F)). Nanoindentation tests were performed to investigate the local mechanical properties of the produced nanocomposite in comparison to the unreinforced chitosan thin films. Nano hardness values (H) and indentation modulus (E) were measured using 5 and 10 µm spherical indenters. The addition of nano fillers enhanced the hardness of both types of films with the amount of hardening being directly proportional to the fraction of nano filler added(p<0.001). Crosslinking has also significantly increased the hardness (p< 0.001). The larger indentation returned a lower hardness. The use of different radii nano indenters underlined the indenter size effect due to the differing strain fields. The promising mechanical properties resulting from this research will allow using the fabricated nanocomposites for tissue engineering, biomedicine, drug delivery, electronics, energy, surface coatings and packaging applications.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"6 1","pages":"11"},"PeriodicalIF":0.0,"publicationDate":"2018-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88678998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents the results of experimental investigation on concrete cylinders confined with two different types of fiber reinforced polymer (FRP) sheets, they are: synthetic high strength CFRP composites and composites using natural fiber like Jute. These two FRPs are very much distinct with respect to their strength and recycle properties. Conventional FRPs like CFRP possess superior mechanical strength than natural FRPs, but have got some serious drawbacks such as high density, high cost and poor recycling and non-biodegradable properties. On the other hand, the durability of the natural fibers can be enhanced by mummification of the fibers within the epoxy resin. An experimental study was conducted, where twenty six small scale cylindrical concrete specimens (100 × 200 mm) were subjected to uniaxial compression up o failure and the corresponding stress-strain behaviors were observed. The ultimate failure load and the deformation at peak load were the two important observations. The results demonstrate that a significant increase in the compressive strength can be achieved by confining the concrete with CFRP but both strength and ductility are compromised when concrete is wrapped with JUTE-FRP. However, JUTE-FRP shows reasonably good ductile behavior for the case of low strength concrete and can safely be used for brick masonry column. For low cost strengthening work, JUTE-FRP can be an alternative for low strength concrete and masonry works.
{"title":"Experimental Behavior of FRP Confined Concrete Cylinder Wrapped by Two Different FRPs","authors":"Ataur Rahman, Madhobi Mallick, Shantanu Ghosh","doi":"10.5539/JMSR.V7N2P18","DOIUrl":"https://doi.org/10.5539/JMSR.V7N2P18","url":null,"abstract":"This paper presents the results of experimental investigation on concrete cylinders confined with two different types of fiber reinforced polymer (FRP) sheets, they are: synthetic high strength CFRP composites and composites using natural fiber like Jute. These two FRPs are very much distinct with respect to their strength and recycle properties. Conventional FRPs like CFRP possess superior mechanical strength than natural FRPs, but have got some serious drawbacks such as high density, high cost and poor recycling and non-biodegradable properties. On the other hand, the durability of the natural fibers can be enhanced by mummification of the fibers within the epoxy resin. An experimental study was conducted, where twenty six small scale cylindrical concrete specimens (100 × 200 mm) were subjected to uniaxial compression up o failure and the corresponding stress-strain behaviors were observed. The ultimate failure load and the deformation at peak load were the two important observations. The results demonstrate that a significant increase in the compressive strength can be achieved by confining the concrete with CFRP but both strength and ductility are compromised when concrete is wrapped with JUTE-FRP. However, JUTE-FRP shows reasonably good ductile behavior for the case of low strength concrete and can safely be used for brick masonry column. For low cost strengthening work, JUTE-FRP can be an alternative for low strength concrete and masonry works.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"38 1","pages":"18"},"PeriodicalIF":0.0,"publicationDate":"2018-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82679994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of this study is to eliminate the limitation of existing shear design equations and to establish a complete set of rational as well as computationally efficient shear design equations. On this goal, a macro physical model, based on 2D nonlinear FEM analysis, for both open and full sandwich beams are developed which can clearly demostrate the contributions of different parts of the sandwich beam in resisting shear force. The proposed model also shows a satisfactory correlation between the experimental and the analytical results. A series of analytical specimens in connection with experimental one are analyzed by engaging a 2D-FEM program and a complete set of shear strength equations are derived with the help of that proposed shear resisting model. The equations for full sandwich beam show a good agreement with experimental and analytical results, whereas equations for open sandwich beam require further investigation to increase their level of accuracy and are not presented here.
{"title":"Shear Resisting Mechanism and Shear Strength Equation for Sandwich Beams","authors":"Ataur Rahman, T. Ueda","doi":"10.5539/JMSR.V7N2P1","DOIUrl":"https://doi.org/10.5539/JMSR.V7N2P1","url":null,"abstract":"The aim of this study is to eliminate the limitation of existing shear design equations and to establish a complete set of rational as well as computationally efficient shear design equations. On this goal, a macro physical model, based on 2D nonlinear FEM analysis, for both open and full sandwich beams are developed which can clearly demostrate the contributions of different parts of the sandwich beam in resisting shear force. The proposed model also shows a satisfactory correlation between the experimental and the analytical results. A series of analytical specimens in connection with experimental one are analyzed by engaging a 2D-FEM program and a complete set of shear strength equations are derived with the help of that proposed shear resisting model. The equations for full sandwich beam show a good agreement with experimental and analytical results, whereas equations for open sandwich beam require further investigation to increase their level of accuracy and are not presented here.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"15 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2018-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81367195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhongqi He, H. N. Cheng, O. M. Olanya, J. Uknalis, Xiaodong Zhang, B. Koplitz, Jibao He
The utilization of cottonseed meal products as valuable industrial materials needs to be exploited. We have recently produced water-washed cottonseed meal, total cottonseed protein, sequentially extracted water- and alkali-soluble proteins, and two residues after the total and sequential protein extractions at a pilot scale. In this work, the surface characteristics of the six cottonseed meal products were examined by scanning electron microscopy (SEM), scanning electron microscopy- energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results showed that the surface properties of the six products differed from those of a commercial soy protein flour examined comparatively in this work. The compact morphology and relative-high N composition were observed in all three protein products, with greater similarity between the total protein and alkali-soluble protein. The surfaces of the two residue products were more porous with polysaccharide features. Washed cottonseed meal possessed the surface features similar to those of the residues. In the meantime, the N-associated functional groups were under-represented in the surfaces of all samples, compared to their bulk composition. Information derived from this work increased the understanding of the surface functional properties of cottonseed meal products, which would benefit their practical utilization.
{"title":"Surface Characterization of Cottonseed Meal Products by SEM, SEM-EDS, XRD and XPS Analysis","authors":"Zhongqi He, H. N. Cheng, O. M. Olanya, J. Uknalis, Xiaodong Zhang, B. Koplitz, Jibao He","doi":"10.5539/JMSR.V7N1P28","DOIUrl":"https://doi.org/10.5539/JMSR.V7N1P28","url":null,"abstract":"The utilization of cottonseed meal products as valuable industrial materials needs to be exploited. We have recently produced water-washed cottonseed meal, total cottonseed protein, sequentially extracted water- and alkali-soluble proteins, and two residues after the total and sequential protein extractions at a pilot scale. In this work, the surface characteristics of the six cottonseed meal products were examined by scanning electron microscopy (SEM), scanning electron microscopy- energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results showed that the surface properties of the six products differed from those of a commercial soy protein flour examined comparatively in this work. The compact morphology and relative-high N composition were observed in all three protein products, with greater similarity between the total protein and alkali-soluble protein. The surfaces of the two residue products were more porous with polysaccharide features. Washed cottonseed meal possessed the surface features similar to those of the residues. In the meantime, the N-associated functional groups were under-represented in the surfaces of all samples, compared to their bulk composition. Information derived from this work increased the understanding of the surface functional properties of cottonseed meal products, which would benefit their practical utilization.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"13 1","pages":"28"},"PeriodicalIF":0.0,"publicationDate":"2017-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84342901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fe-aluminide and alumina reinforced in-situ aluminium based metal matrix composite was prepared by spark plasma sintering (SPS) of aluminium and nanosized Fe2O3 powder mixture. In-situ reinforcements were formed during SPS by exothermal reaction between aluminium and nano-size Fe2O3 particle. The thermal characteristics of the in-situ reaction were studied by differential scanning calorimetry (DSC). Field Emission Scanning Electron Microscopy (FESEM) along with the Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD) techniques were used to study the microstructural architecture of the composites as a function of SPS temperature and the volume fraction of reinforcement. Microhardness measurement of the composite shows significant increase in hardness with increase in SPS temperature and volume fraction of secondary phase.
{"title":"Synthesis and Characterization of Aluminium Base in situ Metal Matrix Composites by Spark Plasma Sintering","authors":"B. Mallik, K. Sikdar, D. Roy","doi":"10.5539/JMSR.V7N1P14","DOIUrl":"https://doi.org/10.5539/JMSR.V7N1P14","url":null,"abstract":"Fe-aluminide and alumina reinforced in-situ aluminium based metal matrix composite was prepared by spark plasma sintering (SPS) of aluminium and nanosized Fe2O3 powder mixture. In-situ reinforcements were formed during SPS by exothermal reaction between aluminium and nano-size Fe2O3 particle. The thermal characteristics of the in-situ reaction were studied by differential scanning calorimetry (DSC). Field Emission Scanning Electron Microscopy (FESEM) along with the Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD) techniques were used to study the microstructural architecture of the composites as a function of SPS temperature and the volume fraction of reinforcement. Microhardness measurement of the composite shows significant increase in hardness with increase in SPS temperature and volume fraction of secondary phase.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"103 1","pages":"14"},"PeriodicalIF":0.0,"publicationDate":"2017-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83746780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effect of ionizing radiations (Alpha, Beta, Gamma) in CdS/p-Si heterojunction solar cells are discussed in this paper. The short-circuit current density parameters before Gamma irradiation conditions have been improved up to 35 mA/cm2 and after Gamma irradiation was 30 mA/cm2. The open circuit voltage before Gamma irradiation was 0.59 and 0.565 V after Gamma irradiation. The limitations of these devices were discussed by investigating the dependence of electrical and efficiency parameters in function of radiation time. The efficiency of the cell before radiation was equal to (11.2%) whenever, after the impact of both Alpha, Beta, and Gamma was follows, 4.7, 4.9, and 5.1% respectively. The fill factor before and after Gamma irradiation was 54.5 and 53 %. Studying and analyzing the cells using the I-V, with the change of time rate of Gamma radiation played a critical role in reducing the efficiency of solar cells. The campaign was carried out with different doses of a series of solar cells by exposing them to different time. The deterioration parameters of CdS/p-Si solar cells by Gamma radiation led to strongly supports the results of minority carrier lifetime, which clearly showed diminishing minority carrier lifetime with increasing radiation dose.
{"title":"Ionizing Radiations (Alpha, Beta, Gamma) Effects on CdS / P-Si Heterojunction Solar Cell for Electrical and Optical Properties","authors":"A. El-Amin, M. H. Saad","doi":"10.5539/JMSR.V7N1P20","DOIUrl":"https://doi.org/10.5539/JMSR.V7N1P20","url":null,"abstract":"The effect of ionizing radiations (Alpha, Beta, Gamma) in CdS/p-Si heterojunction solar cells are discussed in this paper. The short-circuit current density parameters before Gamma irradiation conditions have been improved up to 35 mA/cm2 and after Gamma irradiation was 30 mA/cm2. The open circuit voltage before Gamma irradiation was 0.59 and 0.565 V after Gamma irradiation. The limitations of these devices were discussed by investigating the dependence of electrical and efficiency parameters in function of radiation time. The efficiency of the cell before radiation was equal to (11.2%) whenever, after the impact of both Alpha, Beta, and Gamma was follows, 4.7, 4.9, and 5.1% respectively. The fill factor before and after Gamma irradiation was 54.5 and 53 %. Studying and analyzing the cells using the I-V, with the change of time rate of Gamma radiation played a critical role in reducing the efficiency of solar cells. The campaign was carried out with different doses of a series of solar cells by exposing them to different time. The deterioration parameters of CdS/p-Si solar cells by Gamma radiation led to strongly supports the results of minority carrier lifetime, which clearly showed diminishing minority carrier lifetime with increasing radiation dose.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"45 1","pages":"20"},"PeriodicalIF":0.0,"publicationDate":"2017-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87278208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nickel oxide (NiO)-based composite films with various Cobalt/Nickel (Co/Ni) ratios were fabricated, and the photochromic properties of the resulting films were evaluated. The NiO particle sizes in the composite films with Co/Ni ratios of 0~0.02 were 40~70 nm. Increase in the Co addition ratio to the composite films caused a decrease in the initial transmittance of the films, and the films with Co/Ni ratio of 0.005 and 0.01 showed a larger transmittance modulation. Co addition caused an increase in the bleaching and coloring rates, which were the largest in the film with Co/Ni ratio of 0.005.
{"title":"Improvement in Photochromic Property of Nickel Oxide-Based Photochromic Composite Films by Cobalt Addition","authors":"H. Miyazaki, Narumi Eimori, T. Matsuura, T. Ota","doi":"10.5539/JMSR.V7N1P9","DOIUrl":"https://doi.org/10.5539/JMSR.V7N1P9","url":null,"abstract":"Nickel oxide (NiO)-based composite films with various Cobalt/Nickel (Co/Ni) ratios were fabricated, and the photochromic properties of the resulting films were evaluated. The NiO particle sizes in the composite films with Co/Ni ratios of 0~0.02 were 40~70 nm. Increase in the Co addition ratio to the composite films caused a decrease in the initial transmittance of the films, and the films with Co/Ni ratio of 0.005 and 0.01 showed a larger transmittance modulation. Co addition caused an increase in the bleaching and coloring rates, which were the largest in the film with Co/Ni ratio of 0.005.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"25 1","pages":"9"},"PeriodicalIF":0.0,"publicationDate":"2017-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75109491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
DNA origami technology provides a versatile approach for the chemical assembly of gold nanostructures. In this study the bottom-up approach of self-assembly using DNA in the origami process has been successfully applied to arrange five AuNPs asymmetrically. The DNA origami templates were modified to have binding sites that were extended with sticky ends to facilitate the attachment of the AuNPs. With the help of thiol chemistry, the AuNPs which were covered with DNA complementary to the sticky ends introduced on the DNA origami surfaces, we were able to attach the nanoparticles to the designed sites. It was realized that there were slight differences in the designed distances and the determined ones which were accounted for potentially by the deposition of the structures on the grids for imaging. The structures were characterized with gel electrophoresis and TEM. This asymmetric arrangement has the potential of exhibiting plasmonic behavior and circular dichroism when light is incident on the structure.
{"title":"DNA Origami as a Tool to Design Asymmetric Gold Nanostructures","authors":"G. Amoako, Zhou Ming, M. J. Eghan, S. S. Sackey","doi":"10.5539/JMSR.V7N1P1","DOIUrl":"https://doi.org/10.5539/JMSR.V7N1P1","url":null,"abstract":"DNA origami technology provides a versatile approach for the chemical assembly of gold nanostructures. In this study the bottom-up approach of self-assembly using DNA in the origami process has been successfully applied to arrange five AuNPs asymmetrically. The DNA origami templates were modified to have binding sites that were extended with sticky ends to facilitate the attachment of the AuNPs. With the help of thiol chemistry, the AuNPs which were covered with DNA complementary to the sticky ends introduced on the DNA origami surfaces, we were able to attach the nanoparticles to the designed sites. It was realized that there were slight differences in the designed distances and the determined ones which were accounted for potentially by the deposition of the structures on the grids for imaging. The structures were characterized with gel electrophoresis and TEM. This asymmetric arrangement has the potential of exhibiting plasmonic behavior and circular dichroism when light is incident on the structure.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"7 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2017-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81348687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Noritomi, Jumpei Nishigami, N. Endo, Satoru Kato, K. Uchiyama
We have found that the organic solvent-resistance of Alpha-chymotrypsin (Alpha-CT) is enhanced by adsorbing Alpha-CT onto bamboo charcoal powder (BCP), which is obtained by pyrolyzing bamboo waste under nitrogen atmosphere, and is markedly dependent on the thermodynamic water activity (aw) in organic solvents. When BCP-adsorbed Alpha-CT was immersed in acetonitrile at an appropriate water activity, it effectively enhanced the transesterification of N-acetyl-L-tyrosine ethyl ester (N-Ac-Tyr-OEt) with n-butanol (BuOH) to produce N-acetyl-L-tyrosine butyl ester (N-Ac-Tyr-OBu), compared to the hydrolysis of N-Ac-Tyr-OEt with water to give N-acetyl-L-tyrosine (N-Ac-Tyr-OH). When the water activity was 0.28, the initial rate of transesterification catalyzed by BCP-adsorbed Alpha-CT was about sixty times greater than that catalyzed by free Alpha-CT. Regarding the reaction selectivity which is defined as a ratio of the initial rate of transesterification to that of hydrolysis, BCP-adsorbed α-CT was much superior to free Alpha-CT. The catalytic activity of BCP-adsorbed Alpha-CT was markedly dependent on the reaction temperature. Furthermore, concerning the thermal stability at 50 oC, the half-life of BCP-adsorbed Alpha-CT exhibited 3.8-fold, compared to that of free Alpha-CT.
{"title":"Influence of Water Activity on Protease Adsorbed on Biochar in Organic Solvents","authors":"H. Noritomi, Jumpei Nishigami, N. Endo, Satoru Kato, K. Uchiyama","doi":"10.5539/JMSR.V6N4P96","DOIUrl":"https://doi.org/10.5539/JMSR.V6N4P96","url":null,"abstract":"We have found that the organic solvent-resistance of Alpha-chymotrypsin (Alpha-CT) is enhanced by adsorbing Alpha-CT onto bamboo charcoal powder (BCP), which is obtained by pyrolyzing bamboo waste under nitrogen atmosphere, and is markedly dependent on the thermodynamic water activity (aw) in organic solvents. When BCP-adsorbed Alpha-CT was immersed in acetonitrile at an appropriate water activity, it effectively enhanced the transesterification of N-acetyl-L-tyrosine ethyl ester (N-Ac-Tyr-OEt) with n-butanol (BuOH) to produce N-acetyl-L-tyrosine butyl ester (N-Ac-Tyr-OBu), compared to the hydrolysis of N-Ac-Tyr-OEt with water to give N-acetyl-L-tyrosine (N-Ac-Tyr-OH). When the water activity was 0.28, the initial rate of transesterification catalyzed by BCP-adsorbed Alpha-CT was about sixty times greater than that catalyzed by free Alpha-CT. Regarding the reaction selectivity which is defined as a ratio of the initial rate of transesterification to that of hydrolysis, BCP-adsorbed α-CT was much superior to free Alpha-CT. The catalytic activity of BCP-adsorbed Alpha-CT was markedly dependent on the reaction temperature. Furthermore, concerning the thermal stability at 50 oC, the half-life of BCP-adsorbed Alpha-CT exhibited 3.8-fold, compared to that of free Alpha-CT.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"17 1","pages":"96"},"PeriodicalIF":0.0,"publicationDate":"2017-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85990950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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