Fe-based Prussian blue(Fe-PB)cathode material shows great application potential in sodium(Na)-ion batteries due to its high theoretical capacity,long cycle life,low cost,and simple preparation process.However,the crys...Fe-based Prussian blue(Fe-PB)cathode material shows great application potential in sodium(Na)-ion batteries due to its high theoretical capacity,long cycle life,low cost,and simple preparation process.However,the crystalline water and vacancies of Fe-PB lattice,the low electrical conductivity,and the dissolution of metal ions lead to limited capacity and poor cycling stability.In this work,a perylene tetracarboxylic dianhydride amine(PTCDA)coating layer is successfully fabricated on the surface of Fe-PB by a liquid-phase method.The aminated PTCDA(PTCA)coating not only increases the specific surface area and electronic conductivity but also effectively reduces the crystalline water and vacancies,which avoids the erosion of Fe-PB by electrolyte.Consequently,the PTCA layer reduces the charge transfer resistance,enhances the Na-ion diffusion coefficient,and improves the structure stability.The PTCA-coated Fe-PB exhibits superior Na storage performance with a first discharge capacity of 145.2 mAh g^(−1) at 100 mA g^(−1).Long cycling tests exhibit minimal capacity decay of 0.027%per cycle over 1000 cycles at 1 A g^(−1).Therefore,this PTCA coating strategy has shown promising competence in enhancing the electrochemical performance of Fe-PB,which can potentially serve as a universal electrode coating strategy for Na-ion batteries.展开更多
A new aromatic dianhydride monomer containing pyridine moiety, 2,6-bis[4＇-（3＂,4＂- dicarboxyphenoxy）benzoyl]-pyridine dianhydride （Md）, was synthesized in four steps, starting from 2,6-pyridinedicarboxyl chlorid...A new aromatic dianhydride monomer containing pyridine moiety, 2,6-bis[4＇-（3＂,4＂- dicarboxyphenoxy）benzoyl]-pyridine dianhydride （Md）, was synthesized in four steps, starting from 2,6-pyridinedicarboxyl chloride. A novel pyridine-containing polyimide was prepared via polycondensation of Md with ODA by two-step method. The resulting polyimide exhibits excellent solubility, film-forming capability and high thermal resistance.展开更多
A kind of highly organsoluble polyimide and copolyimides were successfully synthesized from bicyclo（2.2.2）-oct- 7-ene-2,3,5,6-tetracarboxylic dianhydride （BCDA）, the commercial diamine 4,4＇-methylenedianiline （...A kind of highly organsoluble polyimide and copolyimides were successfully synthesized from bicyclo（2.2.2）-oct- 7-ene-2,3,5,6-tetracarboxylic dianhydride （BCDA）, the commercial diamine 4,4＇-methylenedianiline （MDA） and the designed diamine 4,4＇-methylenebis-（2-tert-butylaniline） （MBTBA）. The polyimide from BCDA and MBTBA is highly soluble in conventional low boiling point solvents （such as chloroform, tetrahydrofuran） at room temperature. But the solubility of the copolyimides in conventional solvents decreased with the molar ratio of MBTBA and MDA decreased. When the molar ratio of MBTBA and MDA was larger than 7/3, the copolyimides can be soluble in low boiling point solvents at room temperature to form a transparent, flexible, tough film by solution casting. When the molar ratio of MBTBA and MDA was between 7/3 and 1/9, they can only be soluble in hot dipolar aprotic solvents （such as DMF, NMP etc.） and form films too. The copolyimide was only soluble in m-cresol when the molar ratio of MBTBA and MDA was lower than 1/9. The number-average molecular weights of the soluble copolyimides were larger than 5.8 × 1064 g/mol by GPC and their polydispersity indices were higher than 1.4. Only one glass transition temperature of these copolyimides was detected around 400℃ by DMA. The copolyimides did not show appreciable decomposition up to 430℃ in N2.展开更多
A novel approach to the synthesis of 2,2＇,3,3＇-biphenyltetracarboxylic dianhydride is described. The target compound was prepared by a nickel-catalyzed couplirtg reaction of dimethy 3-chlorophthalate （3-DMCP） for ...A novel approach to the synthesis of 2,2＇,3,3＇-biphenyltetracarboxylic dianhydride is described. The target compound was prepared by a nickel-catalyzed couplirtg reaction of dimethy 3-chlorophthalate （3-DMCP） for 4 h at 70-80 ℃, followed by subsequent hydrolysis of tetra-ester in acid solution and dehydration of tetra-acid, with overall yield of 68%. The structures of the products were characterized by IR, 1H NMR and ^13C NMR respectively.展开更多
X-ray crystal structures of 2,2',3,3'-and 3, 3',4,4'-biphenyltetracarboxylic dianhydride (2,2',3,3'- and 3,3',4,4'-BPDA) were determined. The dianhydride isomers have different symmetr...X-ray crystal structures of 2,2',3,3'-and 3, 3',4,4'-biphenyltetracarboxylic dianhydride (2,2',3,3'- and 3,3',4,4'-BPDA) were determined. The dianhydride isomers have different symmetry caused by difference in two anhydride group positions and the dihedral angles between the two phenyl rings are 62.9°for 2,2',3,3',-BPDA and 0°for 3,3',4,4'-BPDA respectively. The polyimides from 2,2',3,3'-BPDA exhibit enhanced solubility, higher thermal stability, and higher glasstransition temperature (Tg) compared with those from 3,3',4,4'-BPDA.展开更多
To prepare an anode material for Li-ion batteries with high discharge capacity and good cycling stability, disordered carbon （DC） formed by calcinations of 3,4,9,10-perylenetetracarboxylic dianhydride was modified v...To prepare an anode material for Li-ion batteries with high discharge capacity and good cycling stability, disordered carbon （DC） formed by calcinations of 3,4,9,10-perylenetetracarboxylic dianhydride was modified via an acid treatment using a mixture of HNO3 and H2SO4. The modified disordered carbon （MDC） was characterized by Fourier-transform infrared （FTIR） spectroscopy, X-ray diffraction （XRD） analysis, Brtmaner-Emmett-Teller （BET） analysis, and scanning electron microscopy （SEM）. FTIR spectra confirm the successful introduction of carbonyl groups onto the DC surface. Some pores appear in the columnar structure of MDC, as observed in SEM micro- graphs. Li＋ ions intercalation/deintercalation is facilitated by the modified morphology. Electrochemical tests show that the MDC exhibits a significant improvement in discharge capacity and cycling stability. These results indicate that the MDC has strong potential for use as an anode material in Li-ion batteries.展开更多
A facile method for the synthesis of 2,3,3＇,4＇-biphenyltetracarboxylic dianhydride（a-BPDA） was reported,which comprises the steps of the dehalogenative coupling of dimethyl 4-chlorophthalate（4-DMCP） and dimethyl...A facile method for the synthesis of 2,3,3＇,4＇-biphenyltetracarboxylic dianhydride（a-BPDA） was reported,which comprises the steps of the dehalogenative coupling of dimethyl 4-chlorophthalate（4-DMCP） and dimethyl 3-chlorophthalate（3-DMCP） catalyzed by low-cost（Ph 3 P） 2 NiCl 2,the hydrolysis of tetra-ester and the dehydration of tetra-acid.In contrast to the conventional methods,this method has the advantage of low cost,convenient manipulation,available condition,high purity and good overall yield.Moreover,the single crystal structure of a-BPDA was analyzed by X-ray diffraction method.The X-ray data suggest that a-BPDA is a rigid,non-coplanar and non-linear structure.It contains three crystallographically independent molecules,in which the dihedral angles of the two linked phenyl rings are 44.75（4）°,46.37（3）° and 42.32（3）°,respectively.The title molecule is governed by a stronger intermolecular interaction in contrast to van der Waals interaction because of the special positions of anhydride groups.展开更多
Semi-empirical AMI method was used to study 1：1 and 1：2 hydrogen bond complexes formed with perylene dianhydride and pyridine derivatives. The weak interaction energy become bigger as the number of hydrogen bonds in...Semi-empirical AMI method was used to study 1：1 and 1：2 hydrogen bond complexes formed with perylene dianhydride and pyridine derivatives. The weak interaction energy become bigger as the number of hydrogen bonds increases. The donor groups on the host and electron-withdrawing groups on the guest molecules favor hydrogen bonding interactions, and the formation of hydrogen bonding leads to electron density flow from the host to the guest molecules. Electronic spectra of these complexes were computed using INDO/SCI method. Blue-shift of the clectronic absorption spectra for the complexes, comparing that of the host, takes place, and the first peaks for different complexes changed slightly. These are in agreement with the experimcntal results. The cause of blue-shift was discussed, and the electronic transitions were assigned based on theoretical calculations. The potential curve of double proton transfer in the complex was calculated, and the transition state and activated energy relative to the N H bond were obtained.展开更多
We report a facile and high-yielding procedure for preparing biphenyltetracarboxylic dianhydrides (BPDAs). This method relies on a nickel-catalyzed electroreductive coupling reaction of dimethyl 3-chorophthalate (3-DM...We report a facile and high-yielding procedure for preparing biphenyltetracarboxylic dianhydrides (BPDAs). This method relies on a nickel-catalyzed electroreductive coupling reaction of dimethyl 3-chorophthalate (3-DMCP) and/or dimethyl 4-chorophthalate (4-DMCP) with subsequent hydrolysis of tetra-ester and dehydration of tetra-acid.展开更多
Polyimides have been widely used in aerospace and mi- croelectronics due to their excellent mechanical properties and thermo oxidative stability^[1]. However, most of aromatic polyi- mides are severe difficult to proc...Polyimides have been widely used in aerospace and mi- croelectronics due to their excellent mechanical properties and thermo oxidative stability^[1]. However, most of aromatic polyi- mides are severe difficult to process because of their bad solu- bility in common solvents and intractable in their fully imidized forms, which restrict their applications and developments^[2,3]. Therefore, many investigations were focused on improving the dissolvability of polyimides and it was found that the excellent solubilizing units could be obtained from substituted biphenyls^[4-7]. Biphenyltetracarboxylic dianhydrides（BPDAs） are the most important monomers for the synthesis of these compounds. Among them, the synthesis of 2,3,3＇,4＇-/3,3＇,4,4＇- biphenyltetracarboxylic dianhydride has been widely investi- gated, but only a few literatures reported the synthesis of 2,2＇,3,3＇-biphenyltetracarboxylic dianhydride（i-BPDA）^[8-10].展开更多
Biphenyltetracarboxylic dianhydride (2,2',3,3' BPDA), C 16 H 6O 6, M r =294.21, monoclinic, P2 1/c, a=11.694(2), b=8.111(2), c=13 494(3) , β=103.47(3)°, V=1244.7(4) 3, Z=4, D c =1.57...Biphenyltetracarboxylic dianhydride (2,2',3,3' BPDA), C 16 H 6O 6, M r =294.21, monoclinic, P2 1/c, a=11.694(2), b=8.111(2), c=13 494(3) , β=103.47(3)°, V=1244.7(4) 3, Z=4, D c =1.570 g/cm 3 , F (000)=450, Mo Kα radiation( λ =0.71073), μ (Mo Kα )=0.092 mm -1 , R =0.0329 for 2180 observed reflections 〔 I>2σ(I) 〕. 3,3',4,4' Biphenyltetracarboxylic dianhydride (3,3',4,4' BPDA), C 16 H 6O 6, M r =294.21, monoclinic, P2 1/n, a=6.8720(14), b=5.1870(10), c=17.288(4), β=94.96(3)°, V= 613.9(2) 3, Z=2, D c =1 592 gcm -3 , F(000)=300 , μ (Mo Kα )=0.125mm -1 , R =0.0331 for 1079 observed reflections〔 I>2σ(I) 〕. The dianhydride isomers have different symmetry caused by alternating two anhydride group positions and the dihedral angle between the two phenyl rings are 62.9°for 2,2',3,3', BPDA and 0°for 3,3',4,4' BPDA respectively.展开更多
A correlation has been previously described between bifidobacteria counts before and after the use of a dietary additive in human studies. However, to our knowledge no information on this topic has yet been reported i...A correlation has been previously described between bifidobacteria counts before and after the use of a dietary additive in human studies. However, to our knowledge no information on this topic has yet been reported in animals, and no information exists either on similar possible correlations of bacterial groups other than bifidobacteria. The potential prebiotic effects of di-D-fructose dianhydride (DFA)-enriched caramels have been previously reported in laboratory animals, poultry and pigs. In the present work, twelve growing male castrated pigs (41.8 ± 1.9 kg mean BW) were fed in succession on a control (no additive) or DFA-enriched caramel (20 g/kg) containing diets. Another group of 10 pigs (38.0 ± 3.7 kg mean BW) fed on a control diet without any additive was used as negative control. Bacterial log10 number of copies of the 16S rRNA gene was determined in fecal samples by using qPCR. Increased (P10 number of copies were determined in fecal samples of pigs fed on the caramel containing diet compared with non-caramel controls. In addition, for all bacterial groups studied microbiological values co-variated with initial counts and, except for enterobacteria, variations in the fecal bacterial numbers after caramel supplementation correlated (P< 0.05) with the fecal numbers before supplementation. In conclusion, the supplementation of pig diets with DFA-enriched caramels induced significant increases in the fecal number of copies of bacterial groups regarded as beneficial, and variations in the fecal number of copies correlated with the initial fecal number of copies.展开更多
Difructose dianhydride Ⅳ(DFA-Ⅳ) is produced from levan, which is a natural polysaccharide that belongs to the fructan family, through the activity of levan fructotransferase(LF) derived from microorganisms. Recently...Difructose dianhydride Ⅳ(DFA-Ⅳ) is produced from levan, which is a natural polysaccharide that belongs to the fructan family, through the activity of levan fructotransferase(LF) derived from microorganisms. Recently, DFA-Ⅳ has been expected to have diverse applications in the food and medical industry. Here, we examined the potential application of DFA-Ⅳ for in vitro fertilization(ⅣF) in pigs. In the assessment of acrosomal integrity during incubation, intact acrosomal or viable spermatozoa were highly sustained in 0.1% or 0.25% DFA-Ⅳ(69.8%-70.8%,P<0.05). Reactive oxygen species(ROS) levels during sperm incubation decreased following the addition of DFA-Ⅳ, and 0.1 %-0.5% DFA-Ⅳ in particular significantly decreased ROS production relative to that seen with no addition or 0.75% DFA-Ⅳ. Total fertilization(mono + polyspermic oocyte) rate was significantly higher in the addition of0.1% DFA-Ⅳ(94.2%) than with other concentrations(71.8%-86.7%, P<0.05). When using reduced ⅣF times and lower sperm numbers, we found that addition of 0.1%-0.5% DFA-Ⅳ significantly increased the fertilization rate(P<0.05). Fertilized oocytes treated with 0.1% DFA-Ⅳ exhibited higher embryonic development and blastocyst formation than those treated with other concentrations(P<0.05). Consequently, the addition of DFA-Ⅳ during ⅣF improved fertilization and embryonic development, suggesting the possible use of novel sugars for enhancement of assisted reproductive technology(ART) in mammals.展开更多
基金National Key Research and Development Program of China,Grant/Award Number:2022YFB3807700Hubei Natural Science Foundation Innovation Group Project,Grant/Award Number:2022CFA020+2 种基金Joint Funds of the Hubei Natural Science Foundation Innovation and Development,Grant/Award Number:2022CFD034Major Technological Innovation Project of Hubei Science and Technology Department,Grant/Award Number:2019AAA164National Natural Science Foundation of China,Grant/Award Number:2022CFD034。
文摘Fe-based Prussian blue(Fe-PB)cathode material shows great application potential in sodium(Na)-ion batteries due to its high theoretical capacity,long cycle life,low cost,and simple preparation process.However,the crystalline water and vacancies of Fe-PB lattice,the low electrical conductivity,and the dissolution of metal ions lead to limited capacity and poor cycling stability.In this work,a perylene tetracarboxylic dianhydride amine(PTCDA)coating layer is successfully fabricated on the surface of Fe-PB by a liquid-phase method.The aminated PTCDA(PTCA)coating not only increases the specific surface area and electronic conductivity but also effectively reduces the crystalline water and vacancies,which avoids the erosion of Fe-PB by electrolyte.Consequently,the PTCA layer reduces the charge transfer resistance,enhances the Na-ion diffusion coefficient,and improves the structure stability.The PTCA-coated Fe-PB exhibits superior Na storage performance with a first discharge capacity of 145.2 mAh g^(−1) at 100 mA g^(−1).Long cycling tests exhibit minimal capacity decay of 0.027%per cycle over 1000 cycles at 1 A g^(−1).Therefore,this PTCA coating strategy has shown promising competence in enhancing the electrochemical performance of Fe-PB,which can potentially serve as a universal electrode coating strategy for Na-ion batteries.
文摘A new aromatic dianhydride monomer containing pyridine moiety, 2,6-bis[4＇-（3＂,4＂- dicarboxyphenoxy）benzoyl]-pyridine dianhydride （Md）, was synthesized in four steps, starting from 2,6-pyridinedicarboxyl chloride. A novel pyridine-containing polyimide was prepared via polycondensation of Md with ODA by two-step method. The resulting polyimide exhibits excellent solubility, film-forming capability and high thermal resistance.
基金This work was financially supported by the National Basic Research Program (No. 2007CB808000)the Foundation of Chinese Academy of Sciences (Nos. 50633010, 50503012)the Zhejiang Provincial Natural Science Foundation of China (Nos. Y405500, Y405411)
文摘A kind of highly organsoluble polyimide and copolyimides were successfully synthesized from bicyclo（2.2.2）-oct- 7-ene-2,3,5,6-tetracarboxylic dianhydride （BCDA）, the commercial diamine 4,4＇-methylenedianiline （MDA） and the designed diamine 4,4＇-methylenebis-（2-tert-butylaniline） （MBTBA）. The polyimide from BCDA and MBTBA is highly soluble in conventional low boiling point solvents （such as chloroform, tetrahydrofuran） at room temperature. But the solubility of the copolyimides in conventional solvents decreased with the molar ratio of MBTBA and MDA decreased. When the molar ratio of MBTBA and MDA was larger than 7/3, the copolyimides can be soluble in low boiling point solvents at room temperature to form a transparent, flexible, tough film by solution casting. When the molar ratio of MBTBA and MDA was between 7/3 and 1/9, they can only be soluble in hot dipolar aprotic solvents （such as DMF, NMP etc.） and form films too. The copolyimide was only soluble in m-cresol when the molar ratio of MBTBA and MDA was lower than 1/9. The number-average molecular weights of the soluble copolyimides were larger than 5.8 × 1064 g/mol by GPC and their polydispersity indices were higher than 1.4. Only one glass transition temperature of these copolyimides was detected around 400℃ by DMA. The copolyimides did not show appreciable decomposition up to 430℃ in N2.
基金the National Undergraduates' Innovative Experiment Project of Chinathe Undergraduates' Innovative Experiment Project of Sichuan University for financial support.
文摘A novel approach to the synthesis of 2,2＇,3,3＇-biphenyltetracarboxylic dianhydride is described. The target compound was prepared by a nickel-catalyzed couplirtg reaction of dimethy 3-chlorophthalate （3-DMCP） for 4 h at 70-80 ℃, followed by subsequent hydrolysis of tetra-ester in acid solution and dehydration of tetra-acid, with overall yield of 68%. The structures of the products were characterized by IR, 1H NMR and ^13C NMR respectively.
文摘X-ray crystal structures of 2,2',3,3'-and 3, 3',4,4'-biphenyltetracarboxylic dianhydride (2,2',3,3'- and 3,3',4,4'-BPDA) were determined. The dianhydride isomers have different symmetry caused by difference in two anhydride group positions and the dihedral angles between the two phenyl rings are 62.9°for 2,2',3,3',-BPDA and 0°for 3,3',4,4'-BPDA respectively. The polyimides from 2,2',3,3'-BPDA exhibit enhanced solubility, higher thermal stability, and higher glasstransition temperature (Tg) compared with those from 3,3',4,4'-BPDA.
基金financially supported by the National High-Tech Research and Development Program of China(No.2013AA050903)the Beijing Municipal Science and Technology Project(No.Z131100003413002)+1 种基金the Beijing Key Laboratory of Environmental Science and Engineering(No.20131039031)the Beijing Higher Institution Engineering Research Center for Power Battery and Chemical Energy Materials(No.2012039032)
文摘To prepare an anode material for Li-ion batteries with high discharge capacity and good cycling stability, disordered carbon （DC） formed by calcinations of 3,4,9,10-perylenetetracarboxylic dianhydride was modified via an acid treatment using a mixture of HNO3 and H2SO4. The modified disordered carbon （MDC） was characterized by Fourier-transform infrared （FTIR） spectroscopy, X-ray diffraction （XRD） analysis, Brtmaner-Emmett-Teller （BET） analysis, and scanning electron microscopy （SEM）. FTIR spectra confirm the successful introduction of carbonyl groups onto the DC surface. Some pores appear in the columnar structure of MDC, as observed in SEM micro- graphs. Li＋ ions intercalation/deintercalation is facilitated by the modified morphology. Electrochemical tests show that the MDC exhibits a significant improvement in discharge capacity and cycling stability. These results indicate that the MDC has strong potential for use as an anode material in Li-ion batteries.
基金Supported by the Ministry of Education Project Combining the Industry and Teaching with Research of Guangdong Province,China(No.2011B090400062)
文摘A facile method for the synthesis of 2,3,3＇,4＇-biphenyltetracarboxylic dianhydride（a-BPDA） was reported,which comprises the steps of the dehalogenative coupling of dimethyl 4-chlorophthalate（4-DMCP） and dimethyl 3-chlorophthalate（3-DMCP） catalyzed by low-cost（Ph 3 P） 2 NiCl 2,the hydrolysis of tetra-ester and the dehydration of tetra-acid.In contrast to the conventional methods,this method has the advantage of low cost,convenient manipulation,available condition,high purity and good overall yield.Moreover,the single crystal structure of a-BPDA was analyzed by X-ray diffraction method.The X-ray data suggest that a-BPDA is a rigid,non-coplanar and non-linear structure.It contains three crystallographically independent molecules,in which the dihedral angles of the two linked phenyl rings are 44.75（4）°,46.37（3）° and 42.32（3）°,respectively.The title molecule is governed by a stronger intermolecular interaction in contrast to van der Waals interaction because of the special positions of anhydride groups.
文摘Semi-empirical AMI method was used to study 1：1 and 1：2 hydrogen bond complexes formed with perylene dianhydride and pyridine derivatives. The weak interaction energy become bigger as the number of hydrogen bonds increases. The donor groups on the host and electron-withdrawing groups on the guest molecules favor hydrogen bonding interactions, and the formation of hydrogen bonding leads to electron density flow from the host to the guest molecules. Electronic spectra of these complexes were computed using INDO/SCI method. Blue-shift of the clectronic absorption spectra for the complexes, comparing that of the host, takes place, and the first peaks for different complexes changed slightly. These are in agreement with the experimcntal results. The cause of blue-shift was discussed, and the electronic transitions were assigned based on theoretical calculations. The potential curve of double proton transfer in the complex was calculated, and the transition state and activated energy relative to the N H bond were obtained.
文摘We report a facile and high-yielding procedure for preparing biphenyltetracarboxylic dianhydrides (BPDAs). This method relies on a nickel-catalyzed electroreductive coupling reaction of dimethyl 3-chorophthalate (3-DMCP) and/or dimethyl 4-chorophthalate (4-DMCP) with subsequent hydrolysis of tetra-ester and dehydration of tetra-acid.
基金Supported by the Project of Sichuan University of Science and Technology,China(No.11-26)the Ministry of Education Project Combining the Industry and Teaching with Research of Guangdong Province,China(No.2011B090400062)
文摘Polyimides have been widely used in aerospace and mi- croelectronics due to their excellent mechanical properties and thermo oxidative stability^[1]. However, most of aromatic polyi- mides are severe difficult to process because of their bad solu- bility in common solvents and intractable in their fully imidized forms, which restrict their applications and developments^[2,3]. Therefore, many investigations were focused on improving the dissolvability of polyimides and it was found that the excellent solubilizing units could be obtained from substituted biphenyls^[4-7]. Biphenyltetracarboxylic dianhydrides（BPDAs） are the most important monomers for the synthesis of these compounds. Among them, the synthesis of 2,3,3＇,4＇-/3,3＇,4,4＇- biphenyltetracarboxylic dianhydride has been widely investi- gated, but only a few literatures reported the synthesis of 2,2＇,3,3＇-biphenyltetracarboxylic dianhydride（i-BPDA）^[8-10].
文摘Biphenyltetracarboxylic dianhydride (2,2',3,3' BPDA), C 16 H 6O 6, M r =294.21, monoclinic, P2 1/c, a=11.694(2), b=8.111(2), c=13 494(3) , β=103.47(3)°, V=1244.7(4) 3, Z=4, D c =1.570 g/cm 3 , F (000)=450, Mo Kα radiation( λ =0.71073), μ (Mo Kα )=0.092 mm -1 , R =0.0329 for 2180 observed reflections 〔 I>2σ(I) 〕. 3,3',4,4' Biphenyltetracarboxylic dianhydride (3,3',4,4' BPDA), C 16 H 6O 6, M r =294.21, monoclinic, P2 1/n, a=6.8720(14), b=5.1870(10), c=17.288(4), β=94.96(3)°, V= 613.9(2) 3, Z=2, D c =1 592 gcm -3 , F(000)=300 , μ (Mo Kα )=0.125mm -1 , R =0.0331 for 1079 observed reflections〔 I>2σ(I) 〕. The dianhydride isomers have different symmetry caused by alternating two anhydride group positions and the dihedral angle between the two phenyl rings are 62.9°for 2,2',3,3', BPDA and 0°for 3,3',4,4' BPDA respectively.
文摘A correlation has been previously described between bifidobacteria counts before and after the use of a dietary additive in human studies. However, to our knowledge no information on this topic has yet been reported in animals, and no information exists either on similar possible correlations of bacterial groups other than bifidobacteria. The potential prebiotic effects of di-D-fructose dianhydride (DFA)-enriched caramels have been previously reported in laboratory animals, poultry and pigs. In the present work, twelve growing male castrated pigs (41.8 ± 1.9 kg mean BW) were fed in succession on a control (no additive) or DFA-enriched caramel (20 g/kg) containing diets. Another group of 10 pigs (38.0 ± 3.7 kg mean BW) fed on a control diet without any additive was used as negative control. Bacterial log10 number of copies of the 16S rRNA gene was determined in fecal samples by using qPCR. Increased (P10 number of copies were determined in fecal samples of pigs fed on the caramel containing diet compared with non-caramel controls. In addition, for all bacterial groups studied microbiological values co-variated with initial counts and, except for enterobacteria, variations in the fecal bacterial numbers after caramel supplementation correlated (P< 0.05) with the fecal numbers before supplementation. In conclusion, the supplementation of pig diets with DFA-enriched caramels induced significant increases in the fecal number of copies of bacterial groups regarded as beneficial, and variations in the fecal number of copies correlated with the initial fecal number of copies.
基金supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2013R1A6A3A04063769)
文摘Difructose dianhydride Ⅳ(DFA-Ⅳ) is produced from levan, which is a natural polysaccharide that belongs to the fructan family, through the activity of levan fructotransferase(LF) derived from microorganisms. Recently, DFA-Ⅳ has been expected to have diverse applications in the food and medical industry. Here, we examined the potential application of DFA-Ⅳ for in vitro fertilization(ⅣF) in pigs. In the assessment of acrosomal integrity during incubation, intact acrosomal or viable spermatozoa were highly sustained in 0.1% or 0.25% DFA-Ⅳ(69.8%-70.8%,P<0.05). Reactive oxygen species(ROS) levels during sperm incubation decreased following the addition of DFA-Ⅳ, and 0.1 %-0.5% DFA-Ⅳ in particular significantly decreased ROS production relative to that seen with no addition or 0.75% DFA-Ⅳ. Total fertilization(mono + polyspermic oocyte) rate was significantly higher in the addition of0.1% DFA-Ⅳ(94.2%) than with other concentrations(71.8%-86.7%, P<0.05). When using reduced ⅣF times and lower sperm numbers, we found that addition of 0.1%-0.5% DFA-Ⅳ significantly increased the fertilization rate(P<0.05). Fertilized oocytes treated with 0.1% DFA-Ⅳ exhibited higher embryonic development and blastocyst formation than those treated with other concentrations(P<0.05). Consequently, the addition of DFA-Ⅳ during ⅣF improved fertilization and embryonic development, suggesting the possible use of novel sugars for enhancement of assisted reproductive technology(ART) in mammals.
