[Objective] The paper was to evaluate effects of peracetic acid （PAA） combined with calcium treatments on storage quality of Ioquat fruits, so as to pro- vide practical techniques to solve the problems of postharves...[Objective] The paper was to evaluate effects of peracetic acid （PAA） combined with calcium treatments on storage quality of Ioquat fruits, so as to pro- vide practical techniques to solve the problems of postharvest rot and quality deteri- oration for Ioquat fruits. [Method] With Ioquat fruits of Qingzhong variety as materi- als, 0.2%, 0.4% and 0.8% PAA combined with 0.8% CaCI2 was used to soak Ioquat fruits for 4 min, 0.8% CaCl2 and water treatments were set as two controls; the fruits were dried and packaged by 0.02 mm PE bags, then stored under non-chilling low temperature of （7±1） ℃. The indicators related to storage quality of Ioquat fruits were randomly tested once every 3 d, and their variation situations were analyzed. [Result] Compared with two control treatments and 0.2% PAA, 0.8% PAA combined with calcium treatments, the treatment of 0.4% PAA combined with 0.8% CaCl2 could significantly inhibit rot index, weight loss rate, firmness and cell membrane permeability of Ioquat fruits during storage period, which could also effectively delay the reduction of titratable acid, vitamin C, soluble solid content and juice yield, and maintain respiration intensity of fruits at a low level; the appearance and flavor qual- ity of fruits were good after stored for 25 d. [Conclusion] 0.4% PAA combined with 0.8% CaCl2 treatment is an efficient, safe and economical practice technology in an- ti-corrosion and quality preservation for postharvest Ioquat fruits .展开更多
The influences of some factors on the yield of phenylacetic acid in thecarbonylation of benzyl chloride were studied in this paper. These factors included the variety andcontent of catalyst, and that of solvent, way o...The influences of some factors on the yield of phenylacetic acid in thecarbonylation of benzyl chloride were studied in this paper. These factors included the variety andcontent of catalyst, and that of solvent, way of material feeding, reaction temperature, sodiumhydrate concentration, triphenylphosphine content, presence of surfactant, the ratio of organicphase volume to aqueous phase volume etc. The optimum reaction conditions were found to be: with aone-time pour of 0.15 g Pd(PPh_3)_2Cl_2, 0.24 g PPh_3, 75 ml NaOH of 3.5 mol/L, 20 ml benzylchloride and 55 ml n-butyl alcohol, and the reaction was carried out at 50℃ for about 3 hours. Theas-obtained yield of phenylacetic acid was as high as 97.6%. In addition, the influences of thepresence of phenylacetic acid and air in the reaction system were also studied. The results showedthat the presence of air in the system and the entrainment of phenylacetic acid in the circulatingorganic phase had great influence on the reaction rate, the stability and performance of catalystand the yield of phenylacetic acid.展开更多
A new structure with the molecular formula [CdL]n was formed by CdSO4 with 4-carboxymethoxy phenylacetic acid （H2L） through the hydrothermal method. The complex was characterized by elemental analysis and infrared s...A new structure with the molecular formula [CdL]n was formed by CdSO4 with 4-carboxymethoxy phenylacetic acid （H2L） through the hydrothermal method. The complex was characterized by elemental analysis and infrared spectroscopy. The structure of the complex was determined by single-crystal X-ray diffraction, which is of monoclinic system, space group P21/c with a = 10.3887（2）, b = 7.10710（10）, c = 14.7212（2） , β = 120.6940（10）°, V = 934.65（3） 3, Dc = 2.278 g·cm-3, Z = 4, F（000） = 624, S = 1.022, the final R = 0.0187 and wR = 0.0487 for 2000 observer reflections （Ⅰ 〉 2σ（Ⅰ））. The center metal ion Cd（Ⅱ） in the complex is six-coordinated in a distorted octahedral geometry, and is connected with L ligands to form a 3D fishing net structure, which is a novel （3,6） network topology. The luminescence of the complex has been investigated, and the result reveals that it displays luminescent property in the voilet region.展开更多
Three new coordination polymers {[Ag2（2,4-DCPA）（4,4＂-bipy）2（NO3）].（H20）}, （1）, [Ag（2,4-DCPA）（bpp）], （2） and {[Ag（4-DCPA）（bpp）]＇（H20）}, （3）, were synthesized by evaporation methods using 2,4-d...Three new coordination polymers {[Ag2（2,4-DCPA）（4,4＂-bipy）2（NO3）].（H20）}, （1）, [Ag（2,4-DCPA）（bpp）], （2） and {[Ag（4-DCPA）（bpp）]＇（H20）}, （3）, were synthesized by evaporation methods using 2,4-dichlorophenylacetic acid （2,4-DCPA）, 4-chlorophenylacetic acid （4-DCPA）, 4,4＂-dipyridyl （4,4＂-bipy）, 1,3-bis（4-pyridyl）propane（bpp） and AgNO3. Compound 1 crystallizes in monoclinic, space group P21/c with a = 10.035（2）, b = 17.796（3）, c = 16.448（2） A, fl = 104.086（2）°, V= 2705.9（2） A3, Dc = 1.893 g/cm-3, C28H23C12NsO6Ag2, Mr = 812.15, F（000） = 1608,μ（MoKot） = 1.615 mm-1, Z = 4, R = 0.0310, wR = 0.0832 for 4357 observed reflections （I 〉 20（/））, and R = 0.0362, wR = 0.0873 for all data. Compound 2 crystallizes in monoclinic, space group P21/c with a = 9.840（2）, b = 24.971（5）, c = 9.3301（2）°, fl = 117.504（2）°, V= 2033.5（7） A3, Dc = 1.666 g/cm3, C2tH19C12N202Ag, Mr = 510.15, F（000） = 1024,/I（MoKa） = 1.273 mml, Z= 4, R = 0.0315 and wR = 0.0680 for 2853 observed reflections （1 〉 20（/）） and R = 0.0454, wR = 0.0736 for all data. Compound 3 crystallizes in monoclinic, space group P21/n with a = 15.472（4）, b = 9.000（2）, c = 16.262（4） A, fl = 112.049（4）°, V = 2099.0（8） A3, Dc = 1.562 g/cm-3, C2H22C1N203Ag, Mr = 493.73, F（000） = 1000, μ（MoKa） = 1.111 mm-1, Z = 4, R = 0.0296, wR = 0.0821 for 3059 observed reflections （I 〉 2δ-（I））, and R = 0.0398, wR = 0.0986 for all data. The complexes were characterized by elemental analysis, FT-IR, thermogravimetrie analysis （TGA） and X-ray single-crystal structure analysis. Fluorescence properties of complex 3 and PXRD of 1 and 2 have been studied. As a result, in complex 1, the Ag（I） ion is surrounded by two nitrogen atoms from two bipy ligands to form an infinite chain, and adjacent Ag-bipy chains produce ＂＇rungs＂ of a ladder by silver ions contact. And in complexes 2 and 3, the two-dimensional ,β-sheet like layers are obtained by Ag……Ag interactions.展开更多
The effect and mechanism of phenylacetic acid on the proliferation of pancreatic carcinoma cells were investigated in cultured pancreatic carcinoma BXPC-3 cells by means of 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenylt...The effect and mechanism of phenylacetic acid on the proliferation of pancreatic carcinoma cells were investigated in cultured pancreatic carcinoma BXPC-3 cells by means of 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide assay and flow cytometry assay.The results show that the treatment of pancreatic carcinoma cells with phenylacetic acid significantly inhibited the cell proliferation in time-dependent and dose-dependent manners.The proliferation of BXPC-3 cells was inhibited at the stage of S phase,the cells at the end stage of S phase were accumulated abundantly,and thus DNA synthesis could not be accomplished entirely.In addition,the expression of adenosine deaminases acting on RNA（ADARs） mRNA in BXPC-3 cells and pancreatic carcinoma specimen were detected by RT-PCR.Having been treated with phenylacetic acid,ADAR2 mRNA in BXPC-3 cells was significantly decreased,the differences were of statistical significance（P0.01）.Taken together,these results suggest that phenylacetic acid may likely regulate the proliferation of pancreatic carcinoma cells through the regulation of ADAR2 mRNA expression.展开更多
Several macroporous polymeric adsorbents (NDA-999, XAD-8, X-5 and XAD-2) were employed in the study to adsorb phenylacetic acid from aqueous solution. Effect of salt and ambient temperature on adsorption was studied u...Several macroporous polymeric adsorbents (NDA-999, XAD-8, X-5 and XAD-2) were employed in the study to adsorb phenylacetic acid from aqueous solution. Effect of salt and ambient temperature on adsorption was studied using NDA-999 adsorbent and the adsorption process conforms to Freundlich抯 model reasonably. Adsorption dynamics were conducted in batch experiments in order to make clear the mechanism of adsorption process. It is proved that the squared driving force mass transfer model can be adopted to elucidate the process. The treatment process of industrial wastewater containing high strength of phenylacetic acid was proposed for cleaner production of phenylacetic acid.展开更多
Bacteroides species are nearly half of the fecal flora community and some are host symbionts crucial to host nutrition and systemic immunity. Among Bacteroides species B. fragilis strains are considered to be the oppo...Bacteroides species are nearly half of the fecal flora community and some are host symbionts crucial to host nutrition and systemic immunity. Among Bacteroides species B. fragilis strains are considered to be the opportunistic ones, being the most isolated anaerobic bacteria in clinical samples. Cell-free supernatants of 65 B. fragilis strains were assayed and they were capable of inducing vacuolating phenotype on Vero cells lineage. The supernatant of the Bacteroides fragilis ATCC 23745 strain was elicited to have the strongest vacuolating effect on Vero cells monolayers and peritoneal macrophages. Some drastic cell alterations were observed, such as a general disorganization of cytoplasm and chromatin condensation, evidencing cell death. By transmission electron microscopy it was confirmed that the vacuoles observed were, in fact, swollen mitochondria. An immunocytochemical assay, TUNEL, was used to confirm this hypothesis and showed that Vero cells and peritoneal macrophages were dying by apoptotic process after exposition of B. fragilis cell-free supernatant. Physical analysis of the apoptotic factor has revealed properties similar to short-chain fatty acids. After gas chromatography and mass spectrometry analysis, phenylacetic acid (PA) was characterized as the major compound present in the most purified active fraction. We believe that the PA is responsible for the pro-apoptotic effect elicited by the supernatant of B. fragilis cultures.展开更多
Peracetic acid(PAA),known for its environmentally friendly properties as a oxidant and bactericide,is gaining prominence in decontamination and disinfection applications.The primary product of PAA oxidation is acetate...Peracetic acid(PAA),known for its environmentally friendly properties as a oxidant and bactericide,is gaining prominence in decontamination and disinfection applications.The primary product of PAA oxidation is acetate that can serve as an electron acceptor(EA)for the biosynthesis of medium-chain fatty acids(MCFAs)via chain elongation(CE)reactions.Hence,PAA-based pretreatment is supposed to be beneficial for MCFAs production from anaerobic sludge fermentation,as it could enhance organic matter availability,suppress competing microorganisms and furnish EA by providing acetate.However,such a hypothesis has rarely been proved.Here we reveal that PAA-based pretreatment leads to significant exfoliation of extracellular polymeric substances(EPS)from sludge flocs and disruption of proteinic secondary structures,through inducing highly active free radicals and singlet oxygen.The production of MCFAs increases substantially to 11,265.6 mg COD L^(-1),while the undesired byproducts,specifically long-chain alcohols(LCAs),decrease to 723.5 mg COD L^(-1).Microbial activity tests further demonstrate that PAA pretreatment stimulates the CE process,attributed to the up-regulation of functional genes involved in fatty acid biosynthesis pathway.These comprehensive findings provide insights into the effectiveness and mechanisms behind enhanced MCFAs production through PAA-based technology,advancing our understanding of sustainable resource recovery from sewage sludge.展开更多
采用乳液聚合方法将引发剂过硫酸铵(APS)和乳化剂十二烷基硫酸钠(SDS)制备出聚丙烯酸树脂乳液,再加入不同条件交联剂固化成聚丙烯酸(PAA)水凝胶,并探究使用紫外固化和热固化2种不同固化方式及不同固化时间对PAA水凝胶性能的影响。通过...采用乳液聚合方法将引发剂过硫酸铵(APS)和乳化剂十二烷基硫酸钠(SDS)制备出聚丙烯酸树脂乳液,再加入不同条件交联剂固化成聚丙烯酸(PAA)水凝胶,并探究使用紫外固化和热固化2种不同固化方式及不同固化时间对PAA水凝胶性能的影响。通过氮气等温吸脱附曲线测试(Brunauer-Emmet-Teller,BET)、扫描电子显微镜(scanning electron microscope,SEM)、热失重分析(thermogravimetric analysis,TGA)、溶胀度、力学测试等方法,对水凝胶的性能进行表征分析。结果表明,形成的PAA水凝胶主要为片状颗粒材料,在紫外固化20 min条件下,其孔径主要分布在2~4 nm;且在热固化条件下,当交联剂质量浓度为0.06、0.07 g/mL时PAA水凝胶溶胀度可达到667%,在交联剂质量浓度为0.09 g/mL时拉伸强度可达到60 k Pa。综上所述,对比紫外固化和热固化2种方法以及不同条件交联剂下制备的PAA水凝胶的差异,对理解和优化PAA水凝胶的制备具有一定的指导意义。展开更多
A new multifunctional mPEG-b-PAA-grafted chitosan copolymer possessing amino and carboxyl groups,mPEG-b-PAA-g-CHI(compound 6) ,was designed for a potential application in gene/drug delivery and synthesized by the meth...A new multifunctional mPEG-b-PAA-grafted chitosan copolymer possessing amino and carboxyl groups,mPEG-b-PAA-g-CHI(compound 6) ,was designed for a potential application in gene/drug delivery and synthesized by the methods of reversible addition-fragmentation chain transfer(RAFT) polymerization of acrylic acid(AA) and grafting reaction of a biodegradable chitosan(CHI) derivative.Completion of the reactions and characterization of the resulting compounds were demonstrated by 1 H NMR,FTIR and gel permeation chtomatography(GPC) studies.The results show that the molar ratio of amino groups to carboxyl groups in the copolymer(compound 6) is 0.41-0.59.展开更多
基金Supported by Special Fund for Agro-scientific Research in the Public Interest "Tec-hnology Research and Experimental Demonstration of Loquat Industry"(201003073)~~
文摘[Objective] The paper was to evaluate effects of peracetic acid （PAA） combined with calcium treatments on storage quality of Ioquat fruits, so as to pro- vide practical techniques to solve the problems of postharvest rot and quality deteri- oration for Ioquat fruits. [Method] With Ioquat fruits of Qingzhong variety as materi- als, 0.2%, 0.4% and 0.8% PAA combined with 0.8% CaCI2 was used to soak Ioquat fruits for 4 min, 0.8% CaCl2 and water treatments were set as two controls; the fruits were dried and packaged by 0.02 mm PE bags, then stored under non-chilling low temperature of （7±1） ℃. The indicators related to storage quality of Ioquat fruits were randomly tested once every 3 d, and their variation situations were analyzed. [Result] Compared with two control treatments and 0.2% PAA, 0.8% PAA combined with calcium treatments, the treatment of 0.4% PAA combined with 0.8% CaCl2 could significantly inhibit rot index, weight loss rate, firmness and cell membrane permeability of Ioquat fruits during storage period, which could also effectively delay the reduction of titratable acid, vitamin C, soluble solid content and juice yield, and maintain respiration intensity of fruits at a low level; the appearance and flavor qual- ity of fruits were good after stored for 25 d. [Conclusion] 0.4% PAA combined with 0.8% CaCl2 treatment is an efficient, safe and economical practice technology in an- ti-corrosion and quality preservation for postharvest Ioquat fruits .
基金Project supported by the foundation of Scientific and Technological from the Ministry of Education (03071), of Natural Science Foundation of Jiangxi Province (0320013) and of the Youth Foundation of Nanchang University.
文摘The influences of some factors on the yield of phenylacetic acid in thecarbonylation of benzyl chloride were studied in this paper. These factors included the variety andcontent of catalyst, and that of solvent, way of material feeding, reaction temperature, sodiumhydrate concentration, triphenylphosphine content, presence of surfactant, the ratio of organicphase volume to aqueous phase volume etc. The optimum reaction conditions were found to be: with aone-time pour of 0.15 g Pd(PPh_3)_2Cl_2, 0.24 g PPh_3, 75 ml NaOH of 3.5 mol/L, 20 ml benzylchloride and 55 ml n-butyl alcohol, and the reaction was carried out at 50℃ for about 3 hours. Theas-obtained yield of phenylacetic acid was as high as 97.6%. In addition, the influences of thepresence of phenylacetic acid and air in the reaction system were also studied. The results showedthat the presence of air in the system and the entrainment of phenylacetic acid in the circulatingorganic phase had great influence on the reaction rate, the stability and performance of catalystand the yield of phenylacetic acid.
基金Supported by the Natural Science Foundation of Zhejiang Province (Y12B010003)
文摘A new structure with the molecular formula [CdL]n was formed by CdSO4 with 4-carboxymethoxy phenylacetic acid （H2L） through the hydrothermal method. The complex was characterized by elemental analysis and infrared spectroscopy. The structure of the complex was determined by single-crystal X-ray diffraction, which is of monoclinic system, space group P21/c with a = 10.3887（2）, b = 7.10710（10）, c = 14.7212（2） , β = 120.6940（10）°, V = 934.65（3） 3, Dc = 2.278 g·cm-3, Z = 4, F（000） = 624, S = 1.022, the final R = 0.0187 and wR = 0.0487 for 2000 observer reflections （Ⅰ 〉 2σ（Ⅰ））. The center metal ion Cd（Ⅱ） in the complex is six-coordinated in a distorted octahedral geometry, and is connected with L ligands to form a 3D fishing net structure, which is a novel （3,6） network topology. The luminescence of the complex has been investigated, and the result reveals that it displays luminescent property in the voilet region.
基金supported by the Guangdong Science and Technology Department(No.S2012020011054 and 2011B090400415)the Zhanjiang Municipality(No.2011C3108001)projects
文摘Three new coordination polymers {[Ag2（2,4-DCPA）（4,4＂-bipy）2（NO3）].（H20）}, （1）, [Ag（2,4-DCPA）（bpp）], （2） and {[Ag（4-DCPA）（bpp）]＇（H20）}, （3）, were synthesized by evaporation methods using 2,4-dichlorophenylacetic acid （2,4-DCPA）, 4-chlorophenylacetic acid （4-DCPA）, 4,4＂-dipyridyl （4,4＂-bipy）, 1,3-bis（4-pyridyl）propane（bpp） and AgNO3. Compound 1 crystallizes in monoclinic, space group P21/c with a = 10.035（2）, b = 17.796（3）, c = 16.448（2） A, fl = 104.086（2）°, V= 2705.9（2） A3, Dc = 1.893 g/cm-3, C28H23C12NsO6Ag2, Mr = 812.15, F（000） = 1608,μ（MoKot） = 1.615 mm-1, Z = 4, R = 0.0310, wR = 0.0832 for 4357 observed reflections （I 〉 20（/））, and R = 0.0362, wR = 0.0873 for all data. Compound 2 crystallizes in monoclinic, space group P21/c with a = 9.840（2）, b = 24.971（5）, c = 9.3301（2）°, fl = 117.504（2）°, V= 2033.5（7） A3, Dc = 1.666 g/cm3, C2tH19C12N202Ag, Mr = 510.15, F（000） = 1024,/I（MoKa） = 1.273 mml, Z= 4, R = 0.0315 and wR = 0.0680 for 2853 observed reflections （1 〉 20（/）） and R = 0.0454, wR = 0.0736 for all data. Compound 3 crystallizes in monoclinic, space group P21/n with a = 15.472（4）, b = 9.000（2）, c = 16.262（4） A, fl = 112.049（4）°, V = 2099.0（8） A3, Dc = 1.562 g/cm-3, C2H22C1N203Ag, Mr = 493.73, F（000） = 1000, μ（MoKa） = 1.111 mm-1, Z = 4, R = 0.0296, wR = 0.0821 for 3059 observed reflections （I 〉 2δ-（I））, and R = 0.0398, wR = 0.0986 for all data. The complexes were characterized by elemental analysis, FT-IR, thermogravimetrie analysis （TGA） and X-ray single-crystal structure analysis. Fluorescence properties of complex 3 and PXRD of 1 and 2 have been studied. As a result, in complex 1, the Ag（I） ion is surrounded by two nitrogen atoms from two bipy ligands to form an infinite chain, and adjacent Ag-bipy chains produce ＂＇rungs＂ of a ladder by silver ions contact. And in complexes 2 and 3, the two-dimensional ,β-sheet like layers are obtained by Ag……Ag interactions.
基金Supported by the National Natural Science Foundation of China(Nos.30801354 and 30970791)the Jilin Provincial Science & Technology Department,China(No.20080154)
文摘The effect and mechanism of phenylacetic acid on the proliferation of pancreatic carcinoma cells were investigated in cultured pancreatic carcinoma BXPC-3 cells by means of 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide assay and flow cytometry assay.The results show that the treatment of pancreatic carcinoma cells with phenylacetic acid significantly inhibited the cell proliferation in time-dependent and dose-dependent manners.The proliferation of BXPC-3 cells was inhibited at the stage of S phase,the cells at the end stage of S phase were accumulated abundantly,and thus DNA synthesis could not be accomplished entirely.In addition,the expression of adenosine deaminases acting on RNA（ADARs） mRNA in BXPC-3 cells and pancreatic carcinoma specimen were detected by RT-PCR.Having been treated with phenylacetic acid,ADAR2 mRNA in BXPC-3 cells was significantly decreased,the differences were of statistical significance（P0.01）.Taken together,these results suggest that phenylacetic acid may likely regulate the proliferation of pancreatic carcinoma cells through the regulation of ADAR2 mRNA expression.
文摘Several macroporous polymeric adsorbents (NDA-999, XAD-8, X-5 and XAD-2) were employed in the study to adsorb phenylacetic acid from aqueous solution. Effect of salt and ambient temperature on adsorption was studied using NDA-999 adsorbent and the adsorption process conforms to Freundlich抯 model reasonably. Adsorption dynamics were conducted in batch experiments in order to make clear the mechanism of adsorption process. It is proved that the squared driving force mass transfer model can be adopted to elucidate the process. The treatment process of industrial wastewater containing high strength of phenylacetic acid was proposed for cleaner production of phenylacetic acid.
基金supported by grants from the following institutions:CAPES,CNPq,Faperj,Pronex and MCT-CNPq.
文摘Bacteroides species are nearly half of the fecal flora community and some are host symbionts crucial to host nutrition and systemic immunity. Among Bacteroides species B. fragilis strains are considered to be the opportunistic ones, being the most isolated anaerobic bacteria in clinical samples. Cell-free supernatants of 65 B. fragilis strains were assayed and they were capable of inducing vacuolating phenotype on Vero cells lineage. The supernatant of the Bacteroides fragilis ATCC 23745 strain was elicited to have the strongest vacuolating effect on Vero cells monolayers and peritoneal macrophages. Some drastic cell alterations were observed, such as a general disorganization of cytoplasm and chromatin condensation, evidencing cell death. By transmission electron microscopy it was confirmed that the vacuoles observed were, in fact, swollen mitochondria. An immunocytochemical assay, TUNEL, was used to confirm this hypothesis and showed that Vero cells and peritoneal macrophages were dying by apoptotic process after exposition of B. fragilis cell-free supernatant. Physical analysis of the apoptotic factor has revealed properties similar to short-chain fatty acids. After gas chromatography and mass spectrometry analysis, phenylacetic acid (PA) was characterized as the major compound present in the most purified active fraction. We believe that the PA is responsible for the pro-apoptotic effect elicited by the supernatant of B. fragilis cultures.
基金funded by the National Natural Science Foundation of China through project 52000135The first author is funded by the Shanghai Tongji Gao Tingyao Environmental Science&Technology Development Foundation.
文摘Peracetic acid(PAA),known for its environmentally friendly properties as a oxidant and bactericide,is gaining prominence in decontamination and disinfection applications.The primary product of PAA oxidation is acetate that can serve as an electron acceptor(EA)for the biosynthesis of medium-chain fatty acids(MCFAs)via chain elongation(CE)reactions.Hence,PAA-based pretreatment is supposed to be beneficial for MCFAs production from anaerobic sludge fermentation,as it could enhance organic matter availability,suppress competing microorganisms and furnish EA by providing acetate.However,such a hypothesis has rarely been proved.Here we reveal that PAA-based pretreatment leads to significant exfoliation of extracellular polymeric substances(EPS)from sludge flocs and disruption of proteinic secondary structures,through inducing highly active free radicals and singlet oxygen.The production of MCFAs increases substantially to 11,265.6 mg COD L^(-1),while the undesired byproducts,specifically long-chain alcohols(LCAs),decrease to 723.5 mg COD L^(-1).Microbial activity tests further demonstrate that PAA pretreatment stimulates the CE process,attributed to the up-regulation of functional genes involved in fatty acid biosynthesis pathway.These comprehensive findings provide insights into the effectiveness and mechanisms behind enhanced MCFAs production through PAA-based technology,advancing our understanding of sustainable resource recovery from sewage sludge.
文摘采用乳液聚合方法将引发剂过硫酸铵(APS)和乳化剂十二烷基硫酸钠(SDS)制备出聚丙烯酸树脂乳液,再加入不同条件交联剂固化成聚丙烯酸(PAA)水凝胶,并探究使用紫外固化和热固化2种不同固化方式及不同固化时间对PAA水凝胶性能的影响。通过氮气等温吸脱附曲线测试(Brunauer-Emmet-Teller,BET)、扫描电子显微镜(scanning electron microscope,SEM)、热失重分析(thermogravimetric analysis,TGA)、溶胀度、力学测试等方法,对水凝胶的性能进行表征分析。结果表明,形成的PAA水凝胶主要为片状颗粒材料,在紫外固化20 min条件下,其孔径主要分布在2~4 nm;且在热固化条件下,当交联剂质量浓度为0.06、0.07 g/mL时PAA水凝胶溶胀度可达到667%,在交联剂质量浓度为0.09 g/mL时拉伸强度可达到60 k Pa。综上所述,对比紫外固化和热固化2种方法以及不同条件交联剂下制备的PAA水凝胶的差异,对理解和优化PAA水凝胶的制备具有一定的指导意义。
基金Project(20704011) supported by the National Natural Science Foundation of ChinaProject(09JJ3027) supported by the Natural Science Foundation of Hunan Province,ChinaProject(50725825) supported by the National Science Foundation for Distinguished Young Scholars
文摘A new multifunctional mPEG-b-PAA-grafted chitosan copolymer possessing amino and carboxyl groups,mPEG-b-PAA-g-CHI(compound 6) ,was designed for a potential application in gene/drug delivery and synthesized by the methods of reversible addition-fragmentation chain transfer(RAFT) polymerization of acrylic acid(AA) and grafting reaction of a biodegradable chitosan(CHI) derivative.Completion of the reactions and characterization of the resulting compounds were demonstrated by 1 H NMR,FTIR and gel permeation chtomatography(GPC) studies.The results show that the molar ratio of amino groups to carboxyl groups in the copolymer(compound 6) is 0.41-0.59.
