Because of the amalgamation of coal resourcesin Shanxi Province in 2009, coal production centermoved westward in China. The coal outputs of InnerMongolia and Shaanxi got higher. From January
A novel silicon-on-insulator （SOI） power metM-oxide-semiconductor field effect transistor with an interface-gate （IG SOI） structure is proposed, in which the trench polysificon gate extends into the buried oxide l...A novel silicon-on-insulator （SOI） power metM-oxide-semiconductor field effect transistor with an interface-gate （IG SOI） structure is proposed, in which the trench polysificon gate extends into the buried oxide layer （BOX） at the source side and an IG is formed. Firstly, the IG offers an extra accumulation channel for the carriers. Secondly, the subsidiary depletion effect of the IG results in a higher impurity doping for the drift region. A low specific on-resistance is therefore obtained under the condition of a slightly enhanced breakdown voltage for the IG SOI. The influences of structure parameters on the device performances are investigated. Compared with the conventional trench gate SOI and lateral planar gate SOI, the specific on-resistances of the IG SOI are reduced by 36.66% and 25.32% with the breakdown voltages enhanced by 2.28% and 10.83% at the same SOI layer of 3 μm, BOX of 1 μm, and half-cell pitch of 5.5 μm, respectively.展开更多
There is a constant search for biomaterials from natural products like plants for food and industrial applications.The work embodied in this report aimed at investigating the effects of microwave-assisted and soxhlet ...There is a constant search for biomaterials from natural products like plants for food and industrial applications.The work embodied in this report aimed at investigating the effects of microwave-assisted and soxhlet extraction(MAE and SE) techniques on the functional physicochemical quality characteristics of Moringa oleifera seed oil and proteins extracts. M. oleifera seeds were ground to fine powders and oil was extracted by microwave-assisted and soxhlet extraction techniques using petroleum ether. Quality attributes including yield percent, moisture content,iodine, saponification, specific gravity, viscosity, p H, thiobarbituric acid, acid and peroxide values were measured. Mineral and vitamin contents, chemical/functional groups, fatty acid(FA) composition, and reducing power of the oil were evaluated. Metabolomics of protein extracted from the defatted powders were analyzed by nuclear magnetic resonance(NMR). M. oleifera oil from MAE and SE methods had good yield(34.25 ± 0.0%,28.75 ± 0.0%), low moisture content(0.008 ± 0.0%, 0.011 ± 0.0%), non-drying and unsaturated, moderately saponified, less dense(0.91 ± 0.01, 0.92 ± 0.02 g m L^(-1)), had Newtonian flow, were weakly acidic, showed good content of FAs, recorded strong potential for long shelf-life, showed stability against oxidative rancidity and enzymatic hydrolysis, had very rich deposits of micro-and macro-nutrients as well as water-soluble and lipidsoluble vitamins, and functional groups in the oil were reflective of its content of long-and medium-chain triglycerides(LCT and MCT). Monounsaturated and saturated fatty acids(MUFA and SFA) were detected and the oil has excellent ferric ion reducing power. NMR metabolomic assay revealed the presence of nine essential amino acids(EAAs) in the protein extract. MAE technique is a feasible and acceptable alternative for high throughput extraction of M. oleifera oil with high yield and excellent quality attributes. The study revealed that MAE did not impart any remarkable advantage(s) on the physicochemical properties of M. oleifera seed oil and protein compared to SE technique.展开更多
China has published a stricter emission standard for thermal power plants in order to help reduce the power industry's sulfur dioxide emissions by over six
Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. ...Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. In addition, the antioxidant potency of cbitosan derivative-glucosamine sulfate was investigated in various established in vitro systems, such as superoxide （O2^-）/hydroxyl （·OH） radicals scavenging, reducing power, iron ion chelating. The following results are obtained： first, glucosamine sulfate had pronounced scavenging effect on superoxide radical. For example the O2 scavenging activity of glucosamine sulfate was 92.11% at 0.8 mg/mL. Second, the ·OH scavenging activity of glucosamine sulfate was also strong, and was about 50% at 3.2 mg/mL. Third, the reducing power of glucosamine sulfate was more pronounced. The reducing power of glucosamine sulfate was 0.643 at 0.75 mg/mL. However, its potency for ferrous ion chelating was weak. Furthermore, except for ferrous ion chelating potency, the scavenging rate of radical and reducing power of glucosamine sulfate were concentration-dependent and increased with their increasing concentrations, but its ferrous ion chelating potency decreased with the increasing concentration. The multiple antioxidant activities of glucosamine sulfate were evidents of reducing power and superoxide/hydroxyl radicals scavenging ability. These in vitro results suggest the possibility that glucosamine sulfate could be used effectively as an ingredient in health or functional food, to alleviate oxidative stress.展开更多
Unconventional vegetables, in general, are plants that have been largely consumed by the population at some point and, because of changes in eating behavior, now present reduced economic and social expression and have...Unconventional vegetables, in general, are plants that have been largely consumed by the population at some point and, because of changes in eating behavior, now present reduced economic and social expression and have lost ground to other vegetables. The objectives of this study were to perform phytochemical screening of the ethanol extracts of Rumex acetosa L., Tropaeolum majus L., Solanum muricatum, Stachys byzantina K. Koch and Solanum betaceum Cav. and evaluate their antioxidant potentials via the methods involving scavaging of the DPPH free radical and the ABTS radical, phosphomolybdenum and reducing power. In phytochemical screening, five species of unconventional vegetables tested positive for tannins;for sesquiterpene, lactones and other lactones. These tests were positive for Tropaeolum majus L. and Rumex acetosa L., Solanum betaceum Cav. and Solanum muricatum tested negative for steroids. Only Solanum betaceum Cav. gave positive tests for flavonoids. Among the five plant species studied, Stachys byzantina K. Koch presented the greatest antioxidant potential in all the methods evaluated.展开更多
The current study was carried out to determine the bioactivity of P. lentiscus leaf extracts as potential antibacterial and antioxidant properties. The plant extracts were examined for antibacterial activity against a...The current study was carried out to determine the bioactivity of P. lentiscus leaf extracts as potential antibacterial and antioxidant properties. The plant extracts were examined for antibacterial activity against antibiotic-resistant Staphylococcus aureus, Staphylococcus haemolyticus, Pseudomonas aeruginosa, and Proteus mirabilis using the agar well method (according to the guidelines of Clinical and Laboratory Standard Institute). The antioxidant potential of 3 plant leaf extracts was determined by their ability to convert Fe<sup>3+</sup> to Fe<sup>2+</sup> and scavenge the DPPH free radical. At all concentrations studied, the methanolic leaf extract had higher total phenolic and flavonoid content, as well as stronger antioxidant and antibacterial inhibitory activity compared to aqueous extract. Our findings with P. aeruginosa were especially interesting, because this bacterium was inhibited by methanol extract than that of the reference antibiotics. The results also demonstrated a link between DPPH radical scavenging ability, reducing power, and total phenolic and flavonoid content of plant extracts (r > 0.97, R<sup>2</sup> > 0.95, P = 0.01). As a result, the methanolic leaf extract of the chosen plant might be employed as an effective antioxidant and antibacterial agent for the treatment of a variety of morbidities.展开更多
Within the framework of continuum mechanics, the double power series ex- pansion technique is proposed, and a series of reduced one-dimensional （1D） equations for a piezoelectric semiconductor beam are obtained. The...Within the framework of continuum mechanics, the double power series ex- pansion technique is proposed, and a series of reduced one-dimensional （1D） equations for a piezoelectric semiconductor beam are obtained. These derived equations are universal, in which extension, flexure, and shear deformations are all included, and can be degen- erated to a number of special cases, e.g., extensional motion, coupled extensional and flexural motion with shear deformations, and elementary flexural motion without shear deformations. As a typical application, the extensional motion of a ZnO beam is analyzed sequentially. It is revealed that semi-conduction has a great effect on the performance of the piezoelectric semiconductor beam, including static deformations and dynamic be- haviors. A larger initial carrier density will evidently lead to a lower resonant frequency and a smaller displacement response, which is a little similar to the dissipative effect. Both the derived approximate equations and the corresponding qualitative analysis are general and widely applicable, which can clearly interpret the inner physical mechanism of the semiconductor in the piezoelectrics and provide theoretical guidance for further experimental design.展开更多
From (2,3-dihydro-1<i>H</i>-perimidin-2-yl)-phenyl, the substitution of OH group in <i>ortho</i> or <i>para</i> position on the phenyl ring, allows us to synthesize the studied comp...From (2,3-dihydro-1<i>H</i>-perimidin-2-yl)-phenyl, the substitution of OH group in <i>ortho</i> or <i>para</i> position on the phenyl ring, allows us to synthesize the studied compounds. These three compounds have been characterized by conventional spectroscopic methods (NMR and MS). The interest of this work is to review the antioxidant activity of our compounds. The antioxidant activity screening carried out according to FRAP and DPPH methods revealed significant anti-free radical properties for compounds 1 and 2 even at low concentrations. In contrast to the compound 2, compound 3 for which the OH group is substituted in <i>para</i> position has the lowest activity in both cases. Therefore the <i>para</i> position seems to be the least sensitive position to increase the antioxidant activity of this pharmacophore.展开更多
Properties of the active power/angle sub-matrix in the power flow Jacobian for power system analysis are studied. The sub-matrix is a dominant and irreducible matrix under very general conditions of power systems, so ...Properties of the active power/angle sub-matrix in the power flow Jacobian for power system analysis are studied. The sub-matrix is a dominant and irreducible matrix under very general conditions of power systems, so that it is invertible. Also the necessary conditions for its singularity are given. These theoretical results can be used to clarify the ambiguous understanding of the sub-matrix in current literature, and also provide the theoretical foundations for the applications based on reduced power flow Jaeobian. Numerical simulation on the IEEE 118-bus power system is used to illustrate our results.展开更多
Objective： To identify the free radical scavenging activity of ethanolic extract of Evolvulus alsinoides. Methods： The free radical scavenging activity was evaluated by in vitro methods like reducing power assay, to...Objective： To identify the free radical scavenging activity of ethanolic extract of Evolvulus alsinoides. Methods： The free radical scavenging activity was evaluated by in vitro methods like reducing power assay, total antioxidant activity, 2,2-diphenyl-l-picrylhydrazyl （DPPH） reduction, superoxide radical scavenging activity, 2,2＇-azinobis-（3-ethylbenzothiazoline-6-sulfonic acid） （ABTS＊） scavenging activity, hydroxyl radical scavenging assay, and nitric oxide radical scavenging assay, which were studied by using ascorbic acid as standard. Results： The extract showed significant activities in all antioxidant assays compared with the reference antioxidant ascorbic acid. The total antioxidant activity as well as the reducing power was also found to increase in a dose-dependent manner. Conclusion： Evolvulus alsinoides may act as a chemopreventive agent, providing antioxidant properties and offering effective protection from free radicals.展开更多
Response surface method （RSM）, based on Box-Behnken design, was used to optimize the enzymatic hydrolysis conditions of flatfish skin protein hydrolysates （FSPH）. Among the tested proteases, the combination of nut...Response surface method （RSM）, based on Box-Behnken design, was used to optimize the enzymatic hydrolysis conditions of flatfish skin protein hydrolysates （FSPH）. Among the tested proteases, the combination of nutrase and trypsin was selected. The optimal hydrolysis conditions were as follows： pH 7.3, temperature 51.8℃, and the enzyme/substrate （E/S） ratio 2.5; under these conditions, the maximum peptide yield （PY） was 69.41 =1：0.43%. The physiochemical analysis showed that the amino acids （His, Asp and Glu） of FSPH accounted for 18.15%, and FSPH was a mixture of polypeptides mostly distributed among 900-2000 Da. FSPH could exhibit a 93% chelating effect on ferrous ion at a concentration of 400 gg/mL, and also a notable reducing power. This study showed bioprocess for the production of FSPH for the first time, which had a good potential for valuable ingredients in the food, cosmetic and medicine industries.展开更多
文摘Because of the amalgamation of coal resourcesin Shanxi Province in 2009, coal production centermoved westward in China. The coal outputs of InnerMongolia and Shaanxi got higher. From January
基金Supported by the National Natural Science Foundation of China under Grant Nos 61404014 and 61405018the Fundamental Research Funds for the Central Universities under Grant Nos CDJZR12160003 and 106112014CDJZR168801
文摘A novel silicon-on-insulator （SOI） power metM-oxide-semiconductor field effect transistor with an interface-gate （IG SOI） structure is proposed, in which the trench polysificon gate extends into the buried oxide layer （BOX） at the source side and an IG is formed. Firstly, the IG offers an extra accumulation channel for the carriers. Secondly, the subsidiary depletion effect of the IG results in a higher impurity doping for the drift region. A low specific on-resistance is therefore obtained under the condition of a slightly enhanced breakdown voltage for the IG SOI. The influences of structure parameters on the device performances are investigated. Compared with the conventional trench gate SOI and lateral planar gate SOI, the specific on-resistances of the IG SOI are reduced by 36.66% and 25.32% with the breakdown voltages enhanced by 2.28% and 10.83% at the same SOI layer of 3 μm, BOX of 1 μm, and half-cell pitch of 5.5 μm, respectively.
基金funded by International Foundation for Science(IFS)and Organisation for the Prohibition of Chemical Weapons(OPCW)research grant awarded to Dr.Chukwuebuka Emmanuel Umeyor in 2019(Grant number:I-2-F-6448-1).
文摘There is a constant search for biomaterials from natural products like plants for food and industrial applications.The work embodied in this report aimed at investigating the effects of microwave-assisted and soxhlet extraction(MAE and SE) techniques on the functional physicochemical quality characteristics of Moringa oleifera seed oil and proteins extracts. M. oleifera seeds were ground to fine powders and oil was extracted by microwave-assisted and soxhlet extraction techniques using petroleum ether. Quality attributes including yield percent, moisture content,iodine, saponification, specific gravity, viscosity, p H, thiobarbituric acid, acid and peroxide values were measured. Mineral and vitamin contents, chemical/functional groups, fatty acid(FA) composition, and reducing power of the oil were evaluated. Metabolomics of protein extracted from the defatted powders were analyzed by nuclear magnetic resonance(NMR). M. oleifera oil from MAE and SE methods had good yield(34.25 ± 0.0%,28.75 ± 0.0%), low moisture content(0.008 ± 0.0%, 0.011 ± 0.0%), non-drying and unsaturated, moderately saponified, less dense(0.91 ± 0.01, 0.92 ± 0.02 g m L^(-1)), had Newtonian flow, were weakly acidic, showed good content of FAs, recorded strong potential for long shelf-life, showed stability against oxidative rancidity and enzymatic hydrolysis, had very rich deposits of micro-and macro-nutrients as well as water-soluble and lipidsoluble vitamins, and functional groups in the oil were reflective of its content of long-and medium-chain triglycerides(LCT and MCT). Monounsaturated and saturated fatty acids(MUFA and SFA) were detected and the oil has excellent ferric ion reducing power. NMR metabolomic assay revealed the presence of nine essential amino acids(EAAs) in the protein extract. MAE technique is a feasible and acceptable alternative for high throughput extraction of M. oleifera oil with high yield and excellent quality attributes. The study revealed that MAE did not impart any remarkable advantage(s) on the physicochemical properties of M. oleifera seed oil and protein compared to SE technique.
文摘China has published a stricter emission standard for thermal power plants in order to help reduce the power industry's sulfur dioxide emissions by over six
基金Supported by the Talent Program of Chinese Academy of Sciences (Dongbei Zhi Chun)Award Foundation of Scientific Research for Excellent Young and Middle-Age Scientist of Shandong Province (No. 2007BS07002)
文摘Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. In addition, the antioxidant potency of cbitosan derivative-glucosamine sulfate was investigated in various established in vitro systems, such as superoxide （O2^-）/hydroxyl （·OH） radicals scavenging, reducing power, iron ion chelating. The following results are obtained： first, glucosamine sulfate had pronounced scavenging effect on superoxide radical. For example the O2 scavenging activity of glucosamine sulfate was 92.11% at 0.8 mg/mL. Second, the ·OH scavenging activity of glucosamine sulfate was also strong, and was about 50% at 3.2 mg/mL. Third, the reducing power of glucosamine sulfate was more pronounced. The reducing power of glucosamine sulfate was 0.643 at 0.75 mg/mL. However, its potency for ferrous ion chelating was weak. Furthermore, except for ferrous ion chelating potency, the scavenging rate of radical and reducing power of glucosamine sulfate were concentration-dependent and increased with their increasing concentrations, but its ferrous ion chelating potency decreased with the increasing concentration. The multiple antioxidant activities of glucosamine sulfate were evidents of reducing power and superoxide/hydroxyl radicals scavenging ability. These in vitro results suggest the possibility that glucosamine sulfate could be used effectively as an ingredient in health or functional food, to alleviate oxidative stress.
基金The authors thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq)the Coordenacao de Aperfeiçoamento de Pessoal de Nível Superior(CAPES) the Fundacao de AmparoàPesquisa do Estado de Minas Gerais(FAPEMIG)for financial support,a scholarship and a PVNS fellowship(D.L.Nelson).
文摘Unconventional vegetables, in general, are plants that have been largely consumed by the population at some point and, because of changes in eating behavior, now present reduced economic and social expression and have lost ground to other vegetables. The objectives of this study were to perform phytochemical screening of the ethanol extracts of Rumex acetosa L., Tropaeolum majus L., Solanum muricatum, Stachys byzantina K. Koch and Solanum betaceum Cav. and evaluate their antioxidant potentials via the methods involving scavaging of the DPPH free radical and the ABTS radical, phosphomolybdenum and reducing power. In phytochemical screening, five species of unconventional vegetables tested positive for tannins;for sesquiterpene, lactones and other lactones. These tests were positive for Tropaeolum majus L. and Rumex acetosa L., Solanum betaceum Cav. and Solanum muricatum tested negative for steroids. Only Solanum betaceum Cav. gave positive tests for flavonoids. Among the five plant species studied, Stachys byzantina K. Koch presented the greatest antioxidant potential in all the methods evaluated.
文摘The current study was carried out to determine the bioactivity of P. lentiscus leaf extracts as potential antibacterial and antioxidant properties. The plant extracts were examined for antibacterial activity against antibiotic-resistant Staphylococcus aureus, Staphylococcus haemolyticus, Pseudomonas aeruginosa, and Proteus mirabilis using the agar well method (according to the guidelines of Clinical and Laboratory Standard Institute). The antioxidant potential of 3 plant leaf extracts was determined by their ability to convert Fe<sup>3+</sup> to Fe<sup>2+</sup> and scavenge the DPPH free radical. At all concentrations studied, the methanolic leaf extract had higher total phenolic and flavonoid content, as well as stronger antioxidant and antibacterial inhibitory activity compared to aqueous extract. Our findings with P. aeruginosa were especially interesting, because this bacterium was inhibited by methanol extract than that of the reference antibiotics. The results also demonstrated a link between DPPH radical scavenging ability, reducing power, and total phenolic and flavonoid content of plant extracts (r > 0.97, R<sup>2</sup> > 0.95, P = 0.01). As a result, the methanolic leaf extract of the chosen plant might be employed as an effective antioxidant and antibacterial agent for the treatment of a variety of morbidities.
基金Project supported by the National Natural Science Foundation of China(Nos.11672223,11402187,and 51178390)the China Postdoctoral Science Foundation(No.2014M560762)the Fundamental Research Funds for the Central Universities of China(No.xjj2015131)
文摘Within the framework of continuum mechanics, the double power series ex- pansion technique is proposed, and a series of reduced one-dimensional （1D） equations for a piezoelectric semiconductor beam are obtained. These derived equations are universal, in which extension, flexure, and shear deformations are all included, and can be degen- erated to a number of special cases, e.g., extensional motion, coupled extensional and flexural motion with shear deformations, and elementary flexural motion without shear deformations. As a typical application, the extensional motion of a ZnO beam is analyzed sequentially. It is revealed that semi-conduction has a great effect on the performance of the piezoelectric semiconductor beam, including static deformations and dynamic be- haviors. A larger initial carrier density will evidently lead to a lower resonant frequency and a smaller displacement response, which is a little similar to the dissipative effect. Both the derived approximate equations and the corresponding qualitative analysis are general and widely applicable, which can clearly interpret the inner physical mechanism of the semiconductor in the piezoelectrics and provide theoretical guidance for further experimental design.
文摘From (2,3-dihydro-1<i>H</i>-perimidin-2-yl)-phenyl, the substitution of OH group in <i>ortho</i> or <i>para</i> position on the phenyl ring, allows us to synthesize the studied compounds. These three compounds have been characterized by conventional spectroscopic methods (NMR and MS). The interest of this work is to review the antioxidant activity of our compounds. The antioxidant activity screening carried out according to FRAP and DPPH methods revealed significant anti-free radical properties for compounds 1 and 2 even at low concentrations. In contrast to the compound 2, compound 3 for which the OH group is substituted in <i>para</i> position has the lowest activity in both cases. Therefore the <i>para</i> position seems to be the least sensitive position to increase the antioxidant activity of this pharmacophore.
基金the National Natural Science Foundation of China (No. 50307007)
文摘Properties of the active power/angle sub-matrix in the power flow Jacobian for power system analysis are studied. The sub-matrix is a dominant and irreducible matrix under very general conditions of power systems, so that it is invertible. Also the necessary conditions for its singularity are given. These theoretical results can be used to clarify the ambiguous understanding of the sub-matrix in current literature, and also provide the theoretical foundations for the applications based on reduced power flow Jaeobian. Numerical simulation on the IEEE 118-bus power system is used to illustrate our results.
文摘Objective： To identify the free radical scavenging activity of ethanolic extract of Evolvulus alsinoides. Methods： The free radical scavenging activity was evaluated by in vitro methods like reducing power assay, total antioxidant activity, 2,2-diphenyl-l-picrylhydrazyl （DPPH） reduction, superoxide radical scavenging activity, 2,2＇-azinobis-（3-ethylbenzothiazoline-6-sulfonic acid） （ABTS＊） scavenging activity, hydroxyl radical scavenging assay, and nitric oxide radical scavenging assay, which were studied by using ascorbic acid as standard. Results： The extract showed significant activities in all antioxidant assays compared with the reference antioxidant ascorbic acid. The total antioxidant activity as well as the reducing power was also found to increase in a dose-dependent manner. Conclusion： Evolvulus alsinoides may act as a chemopreventive agent, providing antioxidant properties and offering effective protection from free radicals.
文摘Response surface method （RSM）, based on Box-Behnken design, was used to optimize the enzymatic hydrolysis conditions of flatfish skin protein hydrolysates （FSPH）. Among the tested proteases, the combination of nutrase and trypsin was selected. The optimal hydrolysis conditions were as follows： pH 7.3, temperature 51.8℃, and the enzyme/substrate （E/S） ratio 2.5; under these conditions, the maximum peptide yield （PY） was 69.41 =1：0.43%. The physiochemical analysis showed that the amino acids （His, Asp and Glu） of FSPH accounted for 18.15%, and FSPH was a mixture of polypeptides mostly distributed among 900-2000 Da. FSPH could exhibit a 93% chelating effect on ferrous ion at a concentration of 400 gg/mL, and also a notable reducing power. This study showed bioprocess for the production of FSPH for the first time, which had a good potential for valuable ingredients in the food, cosmetic and medicine industries.
