In this article different types of ultradeformable liposomes were designed and the properties of transdermal delivery were studied with sodium salicylate as model drug. These results showed that liposomes with stron...In this article different types of ultradeformable liposomes were designed and the properties of transdermal delivery were studied with sodium salicylate as model drug. These results showed that liposomes with strong hydrophilic surfactant added is a new type of penetration enhancer.展开更多
Surface electromyogram (EMG) signals were identified by fractal dimension.Two patterns of surface EMG signals were acquired from 30 healthy volunteers' right forearm flexor respectively in the process of forearm su...Surface electromyogram (EMG) signals were identified by fractal dimension.Two patterns of surface EMG signals were acquired from 30 healthy volunteers' right forearm flexor respectively in the process of forearm supination (FS) and forearm pronation (FP).After the raw action surface EMG (ASEMG) signal was decomposed into several sub-signals with wavelet packet transform (WPT),five fractal dimensions were respectively calculated from the raw signal and four sub-signals by the method based on fuzzy self-similarity.The results show that calculated from the sub-signal in the band 0 to 125 Hz,the fractal dimensions of FS ASEMG signals and FP ASEMG signals distributed in two different regions,and its error rate based on Bayes decision was no more than 2.26%.Therefore,the fractal dimension is an appropriate feature by which an FS ASEMG signal is distinguished from an FP ASEMG signal.展开更多
Pure tungsten, oxide dispersion strengthened tungsten and carbide dispersion strengthened tungsten were fabricated by high-energy ball milling and spark plasma sintering process. In order to evaluate the properties of...Pure tungsten, oxide dispersion strengthened tungsten and carbide dispersion strengthened tungsten were fabricated by high-energy ball milling and spark plasma sintering process. In order to evaluate the properties of the tungsten alloys under transient high heat flues, four tungsten samples with different grain sizes were tested by high-intensity pulsed ion beam with a heat flux as high as 160 MW/(m^2·s^-1/2). Compared with the commercial tungsten, the surface modification of the oxide dispersion strengthened tungsten by high-intensity pulsed ion beam is completely different. The oxide dispersion strengthened tungsten shows inferior thermal shock response due to the low melting point second phase of Ti and Y2O3, which results in the surface melting, boiling bubbles and cracking. While the carbide dispersion strengthened tungsten shows better thermal shock response than the commercial tungsten.展开更多
Lectin and leghemoglobin in legumes play the important roles, respectively, in recognition of host plants to their rhizobial bacteria, and lowering the oxygen partial pressure around bacteroids and protecting nitrogen...Lectin and leghemoglobin in legumes play the important roles, respectively, in recognition of host plants to their rhizobial bacteria, and lowering the oxygen partial pressure around bacteroids and protecting nitrogenase from oxygen in symbiotic nitrogen-fixing nodules. In order to extend the host range of the rhizobial bacteria and to make them fix nitrogen in non-legumes, pea lectin gene (pl) and Parasponia hemoglobin gene ( phl,) have been constructed into a plant expression vector (pCBHUL) and the vector pCBHUL was introduced into rice calli from immature young embryos by particle bombardment. After the calli were regenerated into plantlets on the resistant-selecting media containing hygromycin, they were identified by PCR and Southern blot hybridization. It was indicated that the pi and phb genes were integrated into nucleic genome of the transformed rice plants. GUS activity and the product of the pi gene were determined by GUS staining, Western blot and in situ hybridization at translational level. Eighteen out of 40 plants resistant to hygromycin were positively identified by PCR analysis with the rate of 45%. The pi gene was expressed in 3 out of 18 plants with 17% and 7.5% in 40 plants. The results may provide a clue for exploring whether Rhizobium leguminosarum by. viceae could extend its host range and make the transgenic rice plants have the possibility of being symbiotic, or associative to nitrogen fixation.展开更多
This article, by using mathematical expressions, offers a scientific framework for understanding how the grading system of Qing′s structural carpentry determines the design and construction in the grand style timber...This article, by using mathematical expressions, offers a scientific framework for understanding how the grading system of Qing′s structural carpentry determines the design and construction in the grand style timber architecture.The Qing′s grand style timber structure, which is ready for prefabrication and assembly, is extremely hierarchical oriented and significantly standardized. The general procedure in designing a grand style timber structure is to start with the grade that defines the basic module (dou kou); next comes with the number of bracket set (cuan), the number of longitudinal bays and the number of purlins which affect its plan and cross section; thirdly choose a roof type that determines its longitudinal section and the facade as well. A series of formulae are conducted to help depict the layout, cross sectional roof curvature and special longitudinal treatments in 4 sloped and 9 spined roofs respectively.展开更多
Writing is one of the difficulties that Chinese students come across during their English study. The differences between Chinese and English on thinking patterns and expressions are the main causes. This article discu...Writing is one of the difficulties that Chinese students come across during their English study. The differences between Chinese and English on thinking patterns and expressions are the main causes. This article discusses some problems existing in Chinese students' English writing, identifies the importance of cross-cultural awareness and ends with some measures in improving English writing teaching.展开更多
In this paper, the group action of a local wild Bocs'rep. category is introduced. And, it computed the parametric numbers U(n) and P(n) of the rep. category mod n(A) and ind n(t) in case n=1,2 with geometric met...In this paper, the group action of a local wild Bocs'rep. category is introduced. And, it computed the parametric numbers U(n) and P(n) of the rep. category mod n(A) and ind n(t) in case n=1,2 with geometric method.展开更多
The Raphanus sativus L. antifungal protein 1 (Rs_AFP1) gene was isolated by polymerase chain reaction (PCR). The complete open reading frame and the fragment encoding the putative mature protein were inserted into the...The Raphanus sativus L. antifungal protein 1 (Rs_AFP1) gene was isolated by polymerase chain reaction (PCR). The complete open reading frame and the fragment encoding the putative mature protein were inserted into the prokaryotic expression vector pET_32b(+), respectively. Subsequent expression showed that the Rs_AFP1 was produced in E. coli as a 27 kD fusion protein only when the N_terminal signal peptide was removed. After treatment with thrombin to remove part of the N_terminal His.tag sequence, the bacterially expressed Rs_AFP1 was used for fungal growth inhibition assay which was conducted on Verticillium dahliae Kleb., a soil_born fungus causing the cotton wilt disease. Results showed that, in the liquid medium, the Rs_AFP1 fusion protein at a concentration of 0.3 g/L clearly inhibited the growth of V. dahliae and the germination of spores. Thus the bacterially expressed fusion protein had the antifungal activity against V. dahliae.展开更多
The Test for English Majors Band-4(TEM4) is annually taken for the second year students in China and it is based on the requirement of English teaching syllabus for English majors. This paper has collected some of s...The Test for English Majors Band-4(TEM4) is annually taken for the second year students in China and it is based on the requirement of English teaching syllabus for English majors. This paper has collected some of students' compositions of TEM-4, and according to the score evaluation of the syllabus as well as TEM-4, the paper aims to analyze students' errors and find out their reasons behind in order to improve students' writing capacity in TEM-4.展开更多
AIM: To investigate the effect of (-)-epigallocatechin-3-gallate (EGCG) on growth of gastric cancer and its possible mechanism. METHODS: Heterotopic tumors were induced by subcutaneously injection of SGC-7901 ce...AIM: To investigate the effect of (-)-epigallocatechin-3-gallate (EGCG) on growth of gastric cancer and its possible mechanism. METHODS: Heterotopic tumors were induced by subcutaneously injection of SGC-7901 cells in nude mice. Tumor growth was measured by calipers in two dimensions. Tumor angiogenesis was determined with tumor microvessel density (MVD) by immunohistology. Vascular endothelial growth factor (VEGF) protein level and activation of signal transducer and activator of transcription 3 (Star3) were examined by Western blotting. VEGF mRNA expression was determined by RT-PCR and VEGF release in tumor culture medium by ELISA. VEGF-induced cell proliferation was studied by MTT assay, cell migration by gelatin modified Boyden chamber (Transwell) and in vitro angiogenesis by endothelial tube formation in Matrigel. RESULTS: Intraperitoneal injection of EGCG inhibited the growth of gastric cancer by 60.4%. MVD in tumor tissues treated with EGCG was markedly reduced. EGCG treatment reduced VEGF protein level in vitro and in vivo. Secretion and mRNA expression of VEGF in tumor cells were also suppressed by EGCG in a dose-dependent manner. This inhibitory effect was associated with reduced activation of Star3, but EGCG treatment did not change the total Star3 expression. EGCG also inhibited VEGF-induced endothelial cell proliferation, migration and tube formation. CONCLUSION: EGCG inhibits the growth of gastric cancer by reducing VEGF production and angiogenesis, and is a promising candidate for anti-angiogenic treatment of gastric cancer.展开更多
While research on pedogenesis mainly focuses on long-term soil formation and most often neglects recent soil evolution in response to human practices or climate changes, this article reviews the impact of artificial s...While research on pedogenesis mainly focuses on long-term soil formation and most often neglects recent soil evolution in response to human practices or climate changes, this article reviews the impact of artificial subsurface drainage on soil evolution. Artificial drainage is considered as an example of the impact of recent changes in water fluxes on soil evolution over time scales of decades to a century. Results from various classical studies on artificial drainage including hydrological and environmental studies are reviewed and collated with rare studies dealing explicitly with soil morphology changes, in response to artificial drainage. We deduce that soil should react to the perturbations associated with subsurface drainage over time scales that do not exceeding a few decades. Subsurface drainage decreases the intensity of erosion and must i) increase the intensity of the lixiviation and eluviation processes, ii) affect iron and manganese dynamics, and iii) induce heterogeneities in soil evolution at the ten meter scale. Such recent soil evolutions can no longer be neglected as they are mostly irreversible and will probably have unknown, but expectable, feedbacks on crucial soil functions such as the sequestration of soil organic matter or the water available capacity.展开更多
This work examines the influence of preparation methods on the physicochemical properties and catalytic performance of MnOx‐CeO2 catalysts for selective catalytic reduction of NO by NH3 (NH3‐SCR) at low temperature....This work examines the influence of preparation methods on the physicochemical properties and catalytic performance of MnOx‐CeO2 catalysts for selective catalytic reduction of NO by NH3 (NH3‐SCR) at low temperature. Five different methods, namely, mechanical mixing, impregnation,hydrothermal treatment, co‐precipitation, and a sol‐gel technique, were used to synthesizeMnOx‐CeO2 catalysts. The catalysts were characterized in detail, and an NH3‐SCR model reaction waschosen to evaluate the catalytic performance. The results showed that the preparation methodsaffected the catalytic performance in the order: hydrothermal treatment > sol‐gel > co‐precipitation> impregnation > mechanical mixing. This order correlated with the surface Ce3+ and Mn4+ content,oxygen vacancies and surface adsorbed oxygen species concentration, and the amount of acidic sitesand acidic strength. This trend is related to redox interactions between MnOx and CeO2. The catalystformed by a hydrothermal treatment exhibited excellent physicochemical properties, optimal catalyticperformance, and good H2O resistance in NH3‐SCR reaction. This was attributed to incorporationof Mnn+ into the CeO2 lattice to form a uniform ceria‐based solid solution (containing Mn‐O‐Cestructures). Strengthening of the electronic interactions between MnOx and CeO2, driven by thehigh‐temperature and high‐pressure conditions during the hydrothermal treatment also improved the catalyst characteristics. Thus, the hydrothermal treatment method is an efficient and environment‐friendly route to synthesizing low‐temperature denitrification (deNOx) catalysts.展开更多
CCAAT/enhancer binding protein α (C/EBPα) is a transcriptional regulatory factor that inhibits cell proliferation, and alternative translational initiation produces two polypeptides, C/EBPαp30 and C/EBPαp42. By ...CCAAT/enhancer binding protein α (C/EBPα) is a transcriptional regulatory factor that inhibits cell proliferation, and alternative translational initiation produces two polypeptides, C/EBPαp30 and C/EBPαp42. By expression profiling, it was revealed that C/EBPap30 specifically inhibited a unique set of genes, including MPP 11, p84N5 and SMYD2, which were not affected by C/EBPαp42 in both QSG-7701 hepatocyte cell line and QGY-7703 hepatoma cells. Semiquantitative RT-PCR analysis independently confirmed these results. Chromatin immunoprecipitation assay showed that C/EBPαp30 bound to the promoters of these genes more strongly than C/EBPαp42. In clinical hepatoma samples in which C/EBPα was downregulated, all three genes specifically inhibited by C/EBPαp30 were upregulated. However, repression of MPP 11, p84N5 and SMYD2 genes might not be directly involved in C/EBPαp30-mediated growth inhibition. Our data suggest that C/EBPαp30 regulates a unique set of target genes and is more than a dominant-negative regulator of C/EBPαp42.展开更多
In the classical multiprocessor scheduling problems, it is assumed that the problems are considered in off\|line or on\|line environment. But in practice, problems are often not really off\|line or on\|line but someh...In the classical multiprocessor scheduling problems, it is assumed that the problems are considered in off\|line or on\|line environment. But in practice, problems are often not really off\|line or on\|line but somehow in between. This means that, with respect to the on\|line problem, some further information about the tasks is available, which allows the improvement of the performance of the best possible algorithms. Problems of this class are called semi on\|line ones. The authors studied two semi on\|line multiprocessor scheduling problems, in which, the total processing time of all tasks is known in advance, or all processing times lie in a given interval. They proposed approximation algorithms for minimizing the makespan and analyzed their performance guarantee. The algorithms improve the known results for 3 or more processor cases in the literature.展开更多
Three supported Ir/TiO_(2)catalysts,containing anatase TiO_(2)nanocrystals with predominantly exposed{101},{100},and{001}planes,were subjected to various pre-treatments(H2 reduction at different temperatures and O_(2)...Three supported Ir/TiO_(2)catalysts,containing anatase TiO_(2)nanocrystals with predominantly exposed{101},{100},and{001}planes,were subjected to various pre-treatments(H2 reduction at different temperatures and O_(2)re-oxidation)and then tested in the vapor phase selective hydrogenation of crotonaldehyde.The pre-treatments significantly altered the Ir-TiO_(x)interactions,including the morphologies and electronic properties of the Ir species and their surface acidity.These interactions were also closely related to the crystal planes of TiO_(2),which further supported the observed reaction behaviors of the various Ir/TiO_(2)catalysts.The best performance was obtained using the Ir/TiO_(2)-{101}catalyst pre-reduced at 300℃,owing to its higher Ir^(0)surface concentration and moderate surface acidity compared to the other catalysts.Moreover,these findings indicated the synergistic role of the Ir-TiO_(x)interface in the reaction,as the interfacial sites were responsible for the adsorption/activation of H_(2)and the C=O bond in the crotonaldehyde molecule.However,pre-reduction at 400℃resulted in partial encapsulation of the Ir particles by TiO_(x)via strong metal-support interactions,which is unfavorable for the catalytic reaction owing to the loss of Ir-TiO_(x)interfacial sites.展开更多
Empirical research was done interviewing face to face a sample of 2,447, 10-12 grade students in Culiacan, Sinaloa, Mexico, from the main public university high school in town. Education is seen as a tool to develop b...Empirical research was done interviewing face to face a sample of 2,447, 10-12 grade students in Culiacan, Sinaloa, Mexico, from the main public university high school in town. Education is seen as a tool to develop better citizens first, and better workers later. The objective of this research was to detect different perceptions related to values and education. Using a 13 items questionnaire, we measured: Students' perceptions about him/herself as part of their education role, responsibility that students show toward activities m school, perceptions about education as a tool to grow in the social ladder and as a way of social recognition, social perception about effort as an important value to self-improve and get social recognition, and to finish, perceptions about their teacher's performance.展开更多
The effect of reducing agents and surfactants on controlling the silver nanoplates was studied. Two reducing agents, trisodium citrate dehydrate (TSC) and potassium tartrate, were used to reduce the AgNO3 solution. In...The effect of reducing agents and surfactants on controlling the silver nanoplates was studied. Two reducing agents, trisodium citrate dehydrate (TSC) and potassium tartrate, were used to reduce the AgNO3 solution. In this redox system, polyvinylpyrrolidone (PVP), sodium dodecyl sulfate (SDS) and arabic gum were served as surfactants. The results showed that reducing agents and surfactants both act as the capping agent adhering to the certain facets of silver seeds to block this surface to grow. The relative intensity of reducing agents also takes an active part in influencing the growth rate and direction of silver seeds. It was also found that halides can accelerate the speed of Ostwald ripening by adding Cl?, Br? and I?into the aqueous and have some effects on the morphology of the nanoplates.展开更多
文摘In this article different types of ultradeformable liposomes were designed and the properties of transdermal delivery were studied with sodium salicylate as model drug. These results showed that liposomes with strong hydrophilic surfactant added is a new type of penetration enhancer.
基金The National Natural Science Foundation of China(No.60171006)the National Basic Research Programof China (973 Pro-gram) (No.2005CB724303).
文摘Surface electromyogram (EMG) signals were identified by fractal dimension.Two patterns of surface EMG signals were acquired from 30 healthy volunteers' right forearm flexor respectively in the process of forearm supination (FS) and forearm pronation (FP).After the raw action surface EMG (ASEMG) signal was decomposed into several sub-signals with wavelet packet transform (WPT),five fractal dimensions were respectively calculated from the raw signal and four sub-signals by the method based on fuzzy self-similarity.The results show that calculated from the sub-signal in the band 0 to 125 Hz,the fractal dimensions of FS ASEMG signals and FP ASEMG signals distributed in two different regions,and its error rate based on Bayes decision was no more than 2.26%.Therefore,the fractal dimension is an appropriate feature by which an FS ASEMG signal is distinguished from an FP ASEMG signal.
基金roject (50634060) supported by the National Natural Science Foundation of ChinaProject (2010GB109000) supported by the National Basic Research Program of China
文摘Pure tungsten, oxide dispersion strengthened tungsten and carbide dispersion strengthened tungsten were fabricated by high-energy ball milling and spark plasma sintering process. In order to evaluate the properties of the tungsten alloys under transient high heat flues, four tungsten samples with different grain sizes were tested by high-intensity pulsed ion beam with a heat flux as high as 160 MW/(m^2·s^-1/2). Compared with the commercial tungsten, the surface modification of the oxide dispersion strengthened tungsten by high-intensity pulsed ion beam is completely different. The oxide dispersion strengthened tungsten shows inferior thermal shock response due to the low melting point second phase of Ti and Y2O3, which results in the surface melting, boiling bubbles and cracking. While the carbide dispersion strengthened tungsten shows better thermal shock response than the commercial tungsten.
文摘Lectin and leghemoglobin in legumes play the important roles, respectively, in recognition of host plants to their rhizobial bacteria, and lowering the oxygen partial pressure around bacteroids and protecting nitrogenase from oxygen in symbiotic nitrogen-fixing nodules. In order to extend the host range of the rhizobial bacteria and to make them fix nitrogen in non-legumes, pea lectin gene (pl) and Parasponia hemoglobin gene ( phl,) have been constructed into a plant expression vector (pCBHUL) and the vector pCBHUL was introduced into rice calli from immature young embryos by particle bombardment. After the calli were regenerated into plantlets on the resistant-selecting media containing hygromycin, they were identified by PCR and Southern blot hybridization. It was indicated that the pi and phb genes were integrated into nucleic genome of the transformed rice plants. GUS activity and the product of the pi gene were determined by GUS staining, Western blot and in situ hybridization at translational level. Eighteen out of 40 plants resistant to hygromycin were positively identified by PCR analysis with the rate of 45%. The pi gene was expressed in 3 out of 18 plants with 17% and 7.5% in 40 plants. The results may provide a clue for exploring whether Rhizobium leguminosarum by. viceae could extend its host range and make the transgenic rice plants have the possibility of being symbiotic, or associative to nitrogen fixation.
文摘This article, by using mathematical expressions, offers a scientific framework for understanding how the grading system of Qing′s structural carpentry determines the design and construction in the grand style timber architecture.The Qing′s grand style timber structure, which is ready for prefabrication and assembly, is extremely hierarchical oriented and significantly standardized. The general procedure in designing a grand style timber structure is to start with the grade that defines the basic module (dou kou); next comes with the number of bracket set (cuan), the number of longitudinal bays and the number of purlins which affect its plan and cross section; thirdly choose a roof type that determines its longitudinal section and the facade as well. A series of formulae are conducted to help depict the layout, cross sectional roof curvature and special longitudinal treatments in 4 sloped and 9 spined roofs respectively.
文摘Writing is one of the difficulties that Chinese students come across during their English study. The differences between Chinese and English on thinking patterns and expressions are the main causes. This article discusses some problems existing in Chinese students' English writing, identifies the importance of cross-cultural awareness and ends with some measures in improving English writing teaching.
文摘In this paper, the group action of a local wild Bocs'rep. category is introduced. And, it computed the parametric numbers U(n) and P(n) of the rep. category mod n(A) and ind n(t) in case n=1,2 with geometric method.
文摘The Raphanus sativus L. antifungal protein 1 (Rs_AFP1) gene was isolated by polymerase chain reaction (PCR). The complete open reading frame and the fragment encoding the putative mature protein were inserted into the prokaryotic expression vector pET_32b(+), respectively. Subsequent expression showed that the Rs_AFP1 was produced in E. coli as a 27 kD fusion protein only when the N_terminal signal peptide was removed. After treatment with thrombin to remove part of the N_terminal His.tag sequence, the bacterially expressed Rs_AFP1 was used for fungal growth inhibition assay which was conducted on Verticillium dahliae Kleb., a soil_born fungus causing the cotton wilt disease. Results showed that, in the liquid medium, the Rs_AFP1 fusion protein at a concentration of 0.3 g/L clearly inhibited the growth of V. dahliae and the germination of spores. Thus the bacterially expressed fusion protein had the antifungal activity against V. dahliae.
文摘The Test for English Majors Band-4(TEM4) is annually taken for the second year students in China and it is based on the requirement of English teaching syllabus for English majors. This paper has collected some of students' compositions of TEM-4, and according to the score evaluation of the syllabus as well as TEM-4, the paper aims to analyze students' errors and find out their reasons behind in order to improve students' writing capacity in TEM-4.
基金Supported by the grants from the National Natural Science Foundation of China, No. 30571833the Natural Science Foundation of Guangdong Province, China, No. 05001785
文摘AIM: To investigate the effect of (-)-epigallocatechin-3-gallate (EGCG) on growth of gastric cancer and its possible mechanism. METHODS: Heterotopic tumors were induced by subcutaneously injection of SGC-7901 cells in nude mice. Tumor growth was measured by calipers in two dimensions. Tumor angiogenesis was determined with tumor microvessel density (MVD) by immunohistology. Vascular endothelial growth factor (VEGF) protein level and activation of signal transducer and activator of transcription 3 (Star3) were examined by Western blotting. VEGF mRNA expression was determined by RT-PCR and VEGF release in tumor culture medium by ELISA. VEGF-induced cell proliferation was studied by MTT assay, cell migration by gelatin modified Boyden chamber (Transwell) and in vitro angiogenesis by endothelial tube formation in Matrigel. RESULTS: Intraperitoneal injection of EGCG inhibited the growth of gastric cancer by 60.4%. MVD in tumor tissues treated with EGCG was markedly reduced. EGCG treatment reduced VEGF protein level in vitro and in vivo. Secretion and mRNA expression of VEGF in tumor cells were also suppressed by EGCG in a dose-dependent manner. This inhibitory effect was associated with reduced activation of Star3, but EGCG treatment did not change the total Star3 expression. EGCG also inhibited VEGF-induced endothelial cell proliferation, migration and tube formation. CONCLUSION: EGCG inhibits the growth of gastric cancer by reducing VEGF production and angiogenesis, and is a promising candidate for anti-angiogenic treatment of gastric cancer.
文摘While research on pedogenesis mainly focuses on long-term soil formation and most often neglects recent soil evolution in response to human practices or climate changes, this article reviews the impact of artificial subsurface drainage on soil evolution. Artificial drainage is considered as an example of the impact of recent changes in water fluxes on soil evolution over time scales of decades to a century. Results from various classical studies on artificial drainage including hydrological and environmental studies are reviewed and collated with rare studies dealing explicitly with soil morphology changes, in response to artificial drainage. We deduce that soil should react to the perturbations associated with subsurface drainage over time scales that do not exceeding a few decades. Subsurface drainage decreases the intensity of erosion and must i) increase the intensity of the lixiviation and eluviation processes, ii) affect iron and manganese dynamics, and iii) induce heterogeneities in soil evolution at the ten meter scale. Such recent soil evolutions can no longer be neglected as they are mostly irreversible and will probably have unknown, but expectable, feedbacks on crucial soil functions such as the sequestration of soil organic matter or the water available capacity.
基金supported by the National Natural Science Foundation of China (No. 21507130)the Open Project Program of Beijing National Laboratory for Molecular Sciences (No. 20140142)+3 种基金the Open Project Program of Chongqing Key Laboratory of Environmental Materials and Remediation Technology from Chongqing University of Arts and Sciences (No. CEK1405)the Open Project Program of Jiangsu Key Laboratory of Vehicle Emissions Control (No. OVEC001)the Open Project Program of Chongqing Key Laboratory of Catalysis and Functional Organic Molecules from Chongqing Technology and Business University (1456029)the Chongqing Science & Technology Commission (Nos. cstc2016jcyj A0070, cstc2014pt-gc20002, cstckjcxljrc13)~~
文摘This work examines the influence of preparation methods on the physicochemical properties and catalytic performance of MnOx‐CeO2 catalysts for selective catalytic reduction of NO by NH3 (NH3‐SCR) at low temperature. Five different methods, namely, mechanical mixing, impregnation,hydrothermal treatment, co‐precipitation, and a sol‐gel technique, were used to synthesizeMnOx‐CeO2 catalysts. The catalysts were characterized in detail, and an NH3‐SCR model reaction waschosen to evaluate the catalytic performance. The results showed that the preparation methodsaffected the catalytic performance in the order: hydrothermal treatment > sol‐gel > co‐precipitation> impregnation > mechanical mixing. This order correlated with the surface Ce3+ and Mn4+ content,oxygen vacancies and surface adsorbed oxygen species concentration, and the amount of acidic sitesand acidic strength. This trend is related to redox interactions between MnOx and CeO2. The catalystformed by a hydrothermal treatment exhibited excellent physicochemical properties, optimal catalyticperformance, and good H2O resistance in NH3‐SCR reaction. This was attributed to incorporationof Mnn+ into the CeO2 lattice to form a uniform ceria‐based solid solution (containing Mn‐O‐Cestructures). Strengthening of the electronic interactions between MnOx and CeO2, driven by thehigh‐temperature and high‐pressure conditions during the hydrothermal treatment also improved the catalyst characteristics. Thus, the hydrothermal treatment method is an efficient and environment‐friendly route to synthesizing low‐temperature denitrification (deNOx) catalysts.
文摘CCAAT/enhancer binding protein α (C/EBPα) is a transcriptional regulatory factor that inhibits cell proliferation, and alternative translational initiation produces two polypeptides, C/EBPαp30 and C/EBPαp42. By expression profiling, it was revealed that C/EBPap30 specifically inhibited a unique set of genes, including MPP 11, p84N5 and SMYD2, which were not affected by C/EBPαp42 in both QSG-7701 hepatocyte cell line and QGY-7703 hepatoma cells. Semiquantitative RT-PCR analysis independently confirmed these results. Chromatin immunoprecipitation assay showed that C/EBPαp30 bound to the promoters of these genes more strongly than C/EBPαp42. In clinical hepatoma samples in which C/EBPα was downregulated, all three genes specifically inhibited by C/EBPαp30 were upregulated. However, repression of MPP 11, p84N5 and SMYD2 genes might not be directly involved in C/EBPαp30-mediated growth inhibition. Our data suggest that C/EBPαp30 regulates a unique set of target genes and is more than a dominant-negative regulator of C/EBPαp42.
文摘In the classical multiprocessor scheduling problems, it is assumed that the problems are considered in off\|line or on\|line environment. But in practice, problems are often not really off\|line or on\|line but somehow in between. This means that, with respect to the on\|line problem, some further information about the tasks is available, which allows the improvement of the performance of the best possible algorithms. Problems of this class are called semi on\|line ones. The authors studied two semi on\|line multiprocessor scheduling problems, in which, the total processing time of all tasks is known in advance, or all processing times lie in a given interval. They proposed approximation algorithms for minimizing the makespan and analyzed their performance guarantee. The algorithms improve the known results for 3 or more processor cases in the literature.
文摘Three supported Ir/TiO_(2)catalysts,containing anatase TiO_(2)nanocrystals with predominantly exposed{101},{100},and{001}planes,were subjected to various pre-treatments(H2 reduction at different temperatures and O_(2)re-oxidation)and then tested in the vapor phase selective hydrogenation of crotonaldehyde.The pre-treatments significantly altered the Ir-TiO_(x)interactions,including the morphologies and electronic properties of the Ir species and their surface acidity.These interactions were also closely related to the crystal planes of TiO_(2),which further supported the observed reaction behaviors of the various Ir/TiO_(2)catalysts.The best performance was obtained using the Ir/TiO_(2)-{101}catalyst pre-reduced at 300℃,owing to its higher Ir^(0)surface concentration and moderate surface acidity compared to the other catalysts.Moreover,these findings indicated the synergistic role of the Ir-TiO_(x)interface in the reaction,as the interfacial sites were responsible for the adsorption/activation of H_(2)and the C=O bond in the crotonaldehyde molecule.However,pre-reduction at 400℃resulted in partial encapsulation of the Ir particles by TiO_(x)via strong metal-support interactions,which is unfavorable for the catalytic reaction owing to the loss of Ir-TiO_(x)interfacial sites.
文摘Empirical research was done interviewing face to face a sample of 2,447, 10-12 grade students in Culiacan, Sinaloa, Mexico, from the main public university high school in town. Education is seen as a tool to develop better citizens first, and better workers later. The objective of this research was to detect different perceptions related to values and education. Using a 13 items questionnaire, we measured: Students' perceptions about him/herself as part of their education role, responsibility that students show toward activities m school, perceptions about education as a tool to grow in the social ladder and as a way of social recognition, social perception about effort as an important value to self-improve and get social recognition, and to finish, perceptions about their teacher's performance.
基金Project(51373097)supported by The National Natural Science Foundation of China
文摘The effect of reducing agents and surfactants on controlling the silver nanoplates was studied. Two reducing agents, trisodium citrate dehydrate (TSC) and potassium tartrate, were used to reduce the AgNO3 solution. In this redox system, polyvinylpyrrolidone (PVP), sodium dodecyl sulfate (SDS) and arabic gum were served as surfactants. The results showed that reducing agents and surfactants both act as the capping agent adhering to the certain facets of silver seeds to block this surface to grow. The relative intensity of reducing agents also takes an active part in influencing the growth rate and direction of silver seeds. It was also found that halides can accelerate the speed of Ostwald ripening by adding Cl?, Br? and I?into the aqueous and have some effects on the morphology of the nanoplates.