Optically active form of α-cyano-3-phenoxybenzyl (CPB) alcohol, building block of pyrethroid insecticides, was synthesized as its acetate by the combination of anion-exchange resin (D301)-catalyzed transcyanation bet...Optically active form of α-cyano-3-phenoxybenzyl (CPB) alcohol, building block of pyrethroid insecticides, was synthesized as its acetate by the combination of anion-exchange resin (D301)-catalyzed transcyanation between m-phenoxybenzaldehyde (m-PBA) and acetone cyanohydrin (AC), and lipase (from Alcaligenes sp.)-catalyzed enantioselective transesterification of the resulting cyanohydrin with vinyl acetate. Through optimizing technological conditions, the catalyzing efficiency was improved considerably compared to methods previously reported. Concentrations of CPB acetate were determined by gas chromatograph. The enantio excess (e.e.) values of CPB acetate were measured by NMR (nuclear magnetic resonance) method. Effects of solvents and temperatures on this reaction were studied. Cyclohexane was shown to be the best solvent among the three tested solvents. 55 °C was the optimal temperature for higher degree of conversion. External diffusion limitation was excluded by raising the rotational speed to 220 r/min. However, internal diffusion could not be ignored, since the catalyst (lipase) was an immobilized enzyme and its particle dimension was not made small enough. The reaction rate was substantially accelerated when the reactant (m-PBA) concentration was as high as 249 mmol/L, but decreased when the initial concentration of m-PBA reached to 277 mmol/L. It was also found that the catalyzing capability of recovered lipase was high enough to use several batches. Study of the mole ratio of AC to m-PBA showed that 2:1 was the best choice. The strategy of adding base catalyst D301 was found to be an important factor in improving the degree of conversion of the reaction from 20% to 80%. The highest degree of conversion of the reaction has reached up to 80%.展开更多
A pot research has been conducted in Horticultural Department Nursery, Faculty of Agricultural and Forestry, Duhok University, during the period of May 15, 2012-Sep. 1, 2012. The study involved in testing the effects ...A pot research has been conducted in Horticultural Department Nursery, Faculty of Agricultural and Forestry, Duhok University, during the period of May 15, 2012-Sep. 1, 2012. The study involved in testing the effects of two amended organic media （loam ＋ sheep manure and loam ＋ peat moss （1：1）） and different concentrations of seaweed （sea force 2） extract including （0, 0.5, 1, 1.5 and 2 mL/L） on growth and flowering of Periwinkle （Vinca rosea） plant. The results showed that growing vinca plants in peat moss medium and spraying sea force 2 extract with low concentrations especially 0.5 mL/L resulted in positive significant difference in vegetative and flowering characteristics.展开更多
A novel spectrofluorimetric method for the determination of L ascorbic acid is proposed. It is based on the inhibition of L ascorbic acid on the formation of 2,3 diaminophenazine, which is an oxidation product of ...A novel spectrofluorimetric method for the determination of L ascorbic acid is proposed. It is based on the inhibition of L ascorbic acid on the formation of 2,3 diaminophenazine, which is an oxidation product of o phenylenediamine catalyzed by laccase .The fluorescence (at λ ex /λ em =464 nm /530 nnm) was enhanced strongly in the presence of organic media . The mechanism of o phenylenediamine oxidation reaction catalyzed by laccase in the presence of L ascorbic acid is discussed .L ascorbic acid is determined in the ethanol, 1,4 dioxane and acetone over the linear range of 4.0×10 -7 ～1.2×10 -4 mol/L, 4.0×10 -7 ～ 8.0×10 -5 mol/L and 4.0×10 -7 ～1.0×10 -4 mol/L with a detection limit of 1.20×10 -8 mol/L,1.19×10 -8 mol/L and 1.24×10 -8 mol/L, respectively. The method has been successfully applied to the simple and rapid determination of L ascorbic acid in pharmaceuticals and milk powder.展开更多
Decomposition of acetone cyanohydrin is the first-step reaction for preparing (S)-α-cyano-3-phenoxybenzyl alcohol (CPBA) by the one-pot method in organic media. Considering the compatibility of biocatalysts with...Decomposition of acetone cyanohydrin is the first-step reaction for preparing (S)-α-cyano-3-phenoxybenzyl alcohol (CPBA) by the one-pot method in organic media. Considering the compatibility of biocatalysts with chemical catalysts and the successive operation in the bioreactor, anion exchange resin (D301) was used as catalyst for this reaction. External diffusion limitation was excluded by raising rotational speed to higher than 190r·min^-1 in both solvents. Internal diffusion limitation was verified to be insignificant in this reaction system. The effect of acetone cyanohydrin concentration on the reaction was also investigated. An intrinsic kinetic model was proposed when the mass transfer limitation was excluded, and the average deviation of the model is 10.5%.展开更多
A well-organized system of internal communication is vital in any organization open to improvement and change, pursuing better management of its resources and caring forgood work atmosphere. Internal communication is ...A well-organized system of internal communication is vital in any organization open to improvement and change, pursuing better management of its resources and caring forgood work atmosphere. Internal communication is primarily to provide efficient, mutual flow of information between employees and management staff at all levels in each area of the organization. In order to present internal communication tools and evaluate their effectiveness a survey study was conducted among the employees of the listed media company Cyfrowy Polsat, one of the two leading private TV groups in Poland. The study involved 136 employees （17% of total employment）. The majority of respondents were male （85%）. All the respondents were 23 to 47 years of age. Almost half were below 24 years of age and 38% represented the age group 25-34 years of age. The majority of respondents declared higher education with master degree and working time exceeding three years. The survey showed that the dominant form of communication is message distribution via electronic channels which confirmed the research assumption that there was a dehumanization of contacts and indirect communication dominated over direct contact. Limited direct contact was also recognized as the major cause of conflicts and disputes. The study was based on the analysis of literature and source materials （reports, statistics, newsletters, and legal acts）. Additionally, the paper provides the presentation of Cyfrowy Polsat＇s position in the Polish media market as well as the strategies and objectives of the company.展开更多
Heavy-metal-free silver based I-III-VI semiconductor nanocrystals(NCs),including ternary silver indium sulfide(AgInS_(2))and derivative quaternary silver indium zinc sulfide(i.e.,AgInZn_(2)S_(4))NCs,possess advantages...Heavy-metal-free silver based I-III-VI semiconductor nanocrystals(NCs),including ternary silver indium sulfide(AgInS_(2))and derivative quaternary silver indium zinc sulfide(i.e.,AgInZn_(2)S_(4))NCs,possess advantages of low toxicity,and size-tunable band gaps approaching near-infrared spectral range,which make them candidates for use in optoelectronic and biological devices.Herein,we report syntheses of AgInS_(2) based NCs starting from In_(2)S_(3) template,which have been performed both in organic and aqueous phase through cation exchange.As a result,ternary silver indium sulfide and quaternary silver indium zinc sulfide NCs are obtained in both organic and aqueous media,and confirmed to be orthorhombic AgInS_(2) NCs and hexagonal AgInZn_(2)S_(4) NCs,respectively.Furthermore,the aqueous AgInZn_(2)S_(4) NCs with red emission and low cytotoxicity are explored for the cancer cell imaging.展开更多
This article reports pollutant removal performances of baffled subsurface flow, and integrated surface flow-floating treatment wetland units, when arranged in series for the treatment of municipal wastewater in Bangla...This article reports pollutant removal performances of baffled subsurface flow, and integrated surface flow-floating treatment wetland units, when arranged in series for the treatment of municipal wastewater in Bangladesh. The wetland units （of the hybrid system） included organic, inorganic media, and were planted with nineteen types of macrophytes. The wetland train was operated under hydraulic loading fluctuation and seasonal variation. The performance analyses （across the wetland units） illustrated simultaneous denitrification and organics removal rates in the first stage vertical flow wetland, due to organic carbon leaching from the employed organic media. Higher mean organics removal rates （656.0 g COD]（m2.day）） did not completely inhibit nitrification in the first stage vertical flow system; such pattern could be linked to effective utilization of the trapped oxygen, as the flow was directed throughout the media by the baffle walls. Second stage horizontal flow wetland showed enhanced biodegradable organics removal, which depleted organic carbon availability for denitrification. The final stage integrated wetland system allowed further nitrogen removal from wastewater, via nutrient uptake by plant roots （along with nitrification）, and generation of organic carbon （by the dead macrophytes） to support denitrification. The system achieved higher E. coli mortality through protozoa predation, E. coli oxidation, and destruction by UV radiation. In general, enhanced pollutant removal efflciencies as demonstrated by the structurally modified hybrid wetland system signify the necessity of such modification, when operated under adverse conditions such as： substantial input organics loading, hydraulic loading fluctuation, and seasonal variation.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 20336010) and the National Basic Research Program (973)of China (No. 2003CB716008)
文摘Optically active form of α-cyano-3-phenoxybenzyl (CPB) alcohol, building block of pyrethroid insecticides, was synthesized as its acetate by the combination of anion-exchange resin (D301)-catalyzed transcyanation between m-phenoxybenzaldehyde (m-PBA) and acetone cyanohydrin (AC), and lipase (from Alcaligenes sp.)-catalyzed enantioselective transesterification of the resulting cyanohydrin with vinyl acetate. Through optimizing technological conditions, the catalyzing efficiency was improved considerably compared to methods previously reported. Concentrations of CPB acetate were determined by gas chromatograph. The enantio excess (e.e.) values of CPB acetate were measured by NMR (nuclear magnetic resonance) method. Effects of solvents and temperatures on this reaction were studied. Cyclohexane was shown to be the best solvent among the three tested solvents. 55 °C was the optimal temperature for higher degree of conversion. External diffusion limitation was excluded by raising the rotational speed to 220 r/min. However, internal diffusion could not be ignored, since the catalyst (lipase) was an immobilized enzyme and its particle dimension was not made small enough. The reaction rate was substantially accelerated when the reactant (m-PBA) concentration was as high as 249 mmol/L, but decreased when the initial concentration of m-PBA reached to 277 mmol/L. It was also found that the catalyzing capability of recovered lipase was high enough to use several batches. Study of the mole ratio of AC to m-PBA showed that 2:1 was the best choice. The strategy of adding base catalyst D301 was found to be an important factor in improving the degree of conversion of the reaction from 20% to 80%. The highest degree of conversion of the reaction has reached up to 80%.
文摘A pot research has been conducted in Horticultural Department Nursery, Faculty of Agricultural and Forestry, Duhok University, during the period of May 15, 2012-Sep. 1, 2012. The study involved in testing the effects of two amended organic media （loam ＋ sheep manure and loam ＋ peat moss （1：1）） and different concentrations of seaweed （sea force 2） extract including （0, 0.5, 1, 1.5 and 2 mL/L） on growth and flowering of Periwinkle （Vinca rosea） plant. The results showed that growing vinca plants in peat moss medium and spraying sea force 2 extract with low concentrations especially 0.5 mL/L resulted in positive significant difference in vegetative and flowering characteristics.
文摘A novel spectrofluorimetric method for the determination of L ascorbic acid is proposed. It is based on the inhibition of L ascorbic acid on the formation of 2,3 diaminophenazine, which is an oxidation product of o phenylenediamine catalyzed by laccase .The fluorescence (at λ ex /λ em =464 nm /530 nnm) was enhanced strongly in the presence of organic media . The mechanism of o phenylenediamine oxidation reaction catalyzed by laccase in the presence of L ascorbic acid is discussed .L ascorbic acid is determined in the ethanol, 1,4 dioxane and acetone over the linear range of 4.0×10 -7 ～1.2×10 -4 mol/L, 4.0×10 -7 ～ 8.0×10 -5 mol/L and 4.0×10 -7 ～1.0×10 -4 mol/L with a detection limit of 1.20×10 -8 mol/L,1.19×10 -8 mol/L and 1.24×10 -8 mol/L, respectively. The method has been successfully applied to the simple and rapid determination of L ascorbic acid in pharmaceuticals and milk powder.
基金Supported by the National Natural Science Foundation of China(No.29876037)and the Natural Science Foundation ofZhejiang Province(No.296068)
文摘Decomposition of acetone cyanohydrin is the first-step reaction for preparing (S)-α-cyano-3-phenoxybenzyl alcohol (CPBA) by the one-pot method in organic media. Considering the compatibility of biocatalysts with chemical catalysts and the successive operation in the bioreactor, anion exchange resin (D301) was used as catalyst for this reaction. External diffusion limitation was excluded by raising rotational speed to higher than 190r·min^-1 in both solvents. Internal diffusion limitation was verified to be insignificant in this reaction system. The effect of acetone cyanohydrin concentration on the reaction was also investigated. An intrinsic kinetic model was proposed when the mass transfer limitation was excluded, and the average deviation of the model is 10.5%.
文摘A well-organized system of internal communication is vital in any organization open to improvement and change, pursuing better management of its resources and caring forgood work atmosphere. Internal communication is primarily to provide efficient, mutual flow of information between employees and management staff at all levels in each area of the organization. In order to present internal communication tools and evaluate their effectiveness a survey study was conducted among the employees of the listed media company Cyfrowy Polsat, one of the two leading private TV groups in Poland. The study involved 136 employees （17% of total employment）. The majority of respondents were male （85%）. All the respondents were 23 to 47 years of age. Almost half were below 24 years of age and 38% represented the age group 25-34 years of age. The majority of respondents declared higher education with master degree and working time exceeding three years. The survey showed that the dominant form of communication is message distribution via electronic channels which confirmed the research assumption that there was a dehumanization of contacts and indirect communication dominated over direct contact. Limited direct contact was also recognized as the major cause of conflicts and disputes. The study was based on the analysis of literature and source materials （reports, statistics, newsletters, and legal acts）. Additionally, the paper provides the presentation of Cyfrowy Polsat＇s position in the Polish media market as well as the strategies and objectives of the company.
基金This work was supported by the National Key R&D Program of China(No.2017YFB1002900)the Natural Science Foundation of Youth Fund Project of China(No.51602024)+2 种基金the National Natural Science Foundation of China(No.2157015)the Talent Introduction Plan of Overseas Top Ranking Professors by the State Administration of Foreign Expert Affairs(No.MSBJLG040)the Germany/Hong Kong Joint Research Scheme sponsored by the Research Grants Council of Hong Kong and the German Academic Exchange Service(No.G-CityU106/18).
文摘Heavy-metal-free silver based I-III-VI semiconductor nanocrystals(NCs),including ternary silver indium sulfide(AgInS_(2))and derivative quaternary silver indium zinc sulfide(i.e.,AgInZn_(2)S_(4))NCs,possess advantages of low toxicity,and size-tunable band gaps approaching near-infrared spectral range,which make them candidates for use in optoelectronic and biological devices.Herein,we report syntheses of AgInS_(2) based NCs starting from In_(2)S_(3) template,which have been performed both in organic and aqueous phase through cation exchange.As a result,ternary silver indium sulfide and quaternary silver indium zinc sulfide NCs are obtained in both organic and aqueous media,and confirmed to be orthorhombic AgInS_(2) NCs and hexagonal AgInZn_(2)S_(4) NCs,respectively.Furthermore,the aqueous AgInZn_(2)S_(4) NCs with red emission and low cytotoxicity are explored for the cancer cell imaging.
文摘This article reports pollutant removal performances of baffled subsurface flow, and integrated surface flow-floating treatment wetland units, when arranged in series for the treatment of municipal wastewater in Bangladesh. The wetland units （of the hybrid system） included organic, inorganic media, and were planted with nineteen types of macrophytes. The wetland train was operated under hydraulic loading fluctuation and seasonal variation. The performance analyses （across the wetland units） illustrated simultaneous denitrification and organics removal rates in the first stage vertical flow wetland, due to organic carbon leaching from the employed organic media. Higher mean organics removal rates （656.0 g COD]（m2.day）） did not completely inhibit nitrification in the first stage vertical flow system; such pattern could be linked to effective utilization of the trapped oxygen, as the flow was directed throughout the media by the baffle walls. Second stage horizontal flow wetland showed enhanced biodegradable organics removal, which depleted organic carbon availability for denitrification. The final stage integrated wetland system allowed further nitrogen removal from wastewater, via nutrient uptake by plant roots （along with nitrification）, and generation of organic carbon （by the dead macrophytes） to support denitrification. The system achieved higher E. coli mortality through protozoa predation, E. coli oxidation, and destruction by UV radiation. In general, enhanced pollutant removal efflciencies as demonstrated by the structurally modified hybrid wetland system signify the necessity of such modification, when operated under adverse conditions such as： substantial input organics loading, hydraulic loading fluctuation, and seasonal variation.
