Collagen from tendon of Yezo sika deer was prepared by limited pepsin digestion. The yield of collagen was very high;35.7% on the basis of lyophilized dry weight. The secondary structure of this collagen was different...Collagen from tendon of Yezo sika deer was prepared by limited pepsin digestion. The yield of collagen was very high;35.7% on the basis of lyophilized dry weight. The secondary structure of this collagen was different from that of porcine skin by ATR-FTIR analysis, although it was the same characteristics, e.g. SDS-PAGE, subunit composition, ther-mal behavior, as porcine collagen. Since taking up a problem of bovine spongiform encephalopathy infection in land animals such as calf or bovine, collagen from aquatic materials has been used in various industries. However, the present study indicates that tendon of Yezo sika deer as by-product of meat industry will have potential as an important collagen source for use in the foods, cosmetics, and medical fields.展开更多
Here,we report a concise and divergent enantioselective total synthesis of marine sesquiterpene quinone meroterpenoids(+)-dysidavarones A–C(1–3)using predysidavarone 6 as a key common intermediate.The highly straine...Here,we report a concise and divergent enantioselective total synthesis of marine sesquiterpene quinone meroterpenoids(+)-dysidavarones A–C(1–3)using predysidavarone 6 as a key common intermediate.The highly strained and bridged eight-membered carbocycle of predysidavarone 6 was constructed by a one-pot intermolecular alkylation and intramolecular arylation of Wieland–Miescher ketone derivative 11 and benzyl bromide 12.The total synthesis of(+)-dysidavarones A–C(1–3)was achieved from predysidavarone 6 in a divergent manner by a late-stage introduction of the ethoxy group,which reveals the possible source of the ethoxy group within(+)-dysidavarones A–C(1–3)and provides a late-stage modifiable route for the synthesis of dysidavarone analogs for further anti-cancer activity evaluation.展开更多
Methanol to aromatics produces multiple products,resulting in a limited selectivity of xylene.Aromatics upgrading is an effective way to produce more valuable xylene product,and different feed ratios generate discrepa...Methanol to aromatics produces multiple products,resulting in a limited selectivity of xylene.Aromatics upgrading is an effective way to produce more valuable xylene product,and different feed ratios generate discrepant product distributions.This work integrates the aromatics separation with toluene disproportionation,transalkylation of toluene and trimethylbenzene,and isomerization of xylene and trimethylbenzene.Exergy and exergoeconomic analyses are conducted to give insights in the splitting ratios of benzene,toluene and heavy aromatics for aromatics upgrading.First,a detailed simulation model is developed in Aspen HYSYS.Then,300 splitting ratio sets of benzene and toluene for conversion are studied to investigate the process performances.The results indicate that there are different preferences for the splitting ratios of benzene and toluene in terms of exergy and exergoeconomic performances.The process generates lower total exergy destruction when the splitting ratio of toluene varies between 0.07 and 0.18,and that of benzene fluctuates between 0.55 and 0.6.Nevertheless,the process presents lower total product unit cost with the splitting ratio of toluene less than 0.18 and that of benzene fluctuating between 0.44 and 0.89.Besides,it is found that distillation is the biggest contributor to the total exergy destruction,accounting for 94.97%.展开更多
为了探究微波预处理对油茶籽毛油抗氧化性的影响,了解油茶籽毛油中抗氧物质的变化规律。以油茶籽仁为原料,研究微波预处理后油清除自由基能力及油中抗氧物质的含量及其抗氧能力变化。结果表明,微波预处理对油茶籽毛油抗氧化能力有显著...为了探究微波预处理对油茶籽毛油抗氧化性的影响,了解油茶籽毛油中抗氧物质的变化规律。以油茶籽仁为原料,研究微波预处理后油清除自由基能力及油中抗氧物质的含量及其抗氧能力变化。结果表明,微波预处理对油茶籽毛油抗氧化能力有显著影响。在700 W 20 min处油茶籽毛油DPPH含量有最大值,为(337.08±6.07)μg TE/g。微波预处理后总酚含量呈现上升趋势,含量最高为700 W 20 min处,为(193.04±9.38)μg GAE/g。其ABTS阳离子自由基清除能力小于FRAP还原能力。美拉德产物含量经微波预处理后变化显著,5-羟甲基糠醛(5-HMF)在560 W 20 min处有最大值,为(26.76±1.46)μg/g,丙酮醛(MGO)和3-脱氧葡萄糖醛酮(3-DG)在700 W 20 min处有最大值,分别为(13.60±2.18)、(75.46±3.79)μg/g。展开更多
It is proved that if G is a (+1)-colorable graph, so are the graphs G×Pn and C×Cn, where Pn and Cn are respectively the path and cycle with n vertices, and the maximum edge degree of the graph. The exact ch...It is proved that if G is a (+1)-colorable graph, so are the graphs G×Pn and C×Cn, where Pn and Cn are respectively the path and cycle with n vertices, and the maximum edge degree of the graph. The exact chromatic numbers of the product graphs and are also presented. Thus the total coloring conjecture is proved to be true for many other graphs.展开更多
Structure units containing all-carbon quaternary stereogenic center are found in many bioactive natural products. However, enantioselective construction of this type of structure units has been a formidable challenge ...Structure units containing all-carbon quaternary stereogenic center are found in many bioactive natural products. However, enantioselective construction of this type of structure units has been a formidable challenge for synthetic community due to the steric hindrance enforced by all-carbon quatemary stereocenters. In this review, we present the achievements made by Chinese scientists in the area of asymmetric synthesis of all-carbon quaternary stereocenters in natural products during the past two years.展开更多
Natural product mayamycin is the first example in the angucycline class featuring a C-glycoside linkage at the C5-position of the benz[a]anthracenone core with remarkable biological activities. We successfully synthes...Natural product mayamycin is the first example in the angucycline class featuring a C-glycoside linkage at the C5-position of the benz[a]anthracenone core with remarkable biological activities. We successfully synthesized the two retrosynthetic fragments, but found that the final C-glycosylation did not occur. Alternatively, an A-ring satu- rated aglycon was prepared, but the proposed C-glycosylation still did not proceed. Finally, a simplified substrate was used and the subsequent C-glycosylation went through smoothly, giving a two-ring less analogue of mayamy- cin.展开更多
A novel cyclic prenylated phenylpropanoid, pondaplin 1, was first synthesized in 26% overall yields through an expeditious route (7 steps) that employed highly regio- and stereoselective phenyltellurenylation to aryla...A novel cyclic prenylated phenylpropanoid, pondaplin 1, was first synthesized in 26% overall yields through an expeditious route (7 steps) that employed highly regio- and stereoselective phenyltellurenylation to arylacetylene and palladium (II) chloride-catalyzed carbonylation of hydroxy styryl phenyl telluride as key steps.展开更多
Asymmetric catalysis has continued to enable the preparation of optically active natural products over the past decade.This minireview summarizes progress in the catalytic enantioselective total synthesis of complex m...Asymmetric catalysis has continued to enable the preparation of optically active natural products over the past decade.This minireview summarizes progress in the catalytic enantioselective total synthesis of complex monoterpenoid indole alkaloids covering the reports from 2019 to June 2021.In particular,the generation of the key chiral stereogenic centers with metal catalysts and organocatalysts has been highlighted,showcasing the power of asymmetric catalysis protocols in accessing complex molecular architectures.展开更多
文摘Collagen from tendon of Yezo sika deer was prepared by limited pepsin digestion. The yield of collagen was very high;35.7% on the basis of lyophilized dry weight. The secondary structure of this collagen was different from that of porcine skin by ATR-FTIR analysis, although it was the same characteristics, e.g. SDS-PAGE, subunit composition, ther-mal behavior, as porcine collagen. Since taking up a problem of bovine spongiform encephalopathy infection in land animals such as calf or bovine, collagen from aquatic materials has been used in various industries. However, the present study indicates that tendon of Yezo sika deer as by-product of meat industry will have potential as an important collagen source for use in the foods, cosmetics, and medical fields.
基金financially supported by the National Natural Science Foundation of China(Nos.22171146,21971121,and 22188101 to ZL)the China Postdoctoral Science Foundation(No.2021M701775 to CC)。
文摘Here,we report a concise and divergent enantioselective total synthesis of marine sesquiterpene quinone meroterpenoids(+)-dysidavarones A–C(1–3)using predysidavarone 6 as a key common intermediate.The highly strained and bridged eight-membered carbocycle of predysidavarone 6 was constructed by a one-pot intermolecular alkylation and intramolecular arylation of Wieland–Miescher ketone derivative 11 and benzyl bromide 12.The total synthesis of(+)-dysidavarones A–C(1–3)was achieved from predysidavarone 6 in a divergent manner by a late-stage introduction of the ethoxy group,which reveals the possible source of the ethoxy group within(+)-dysidavarones A–C(1–3)and provides a late-stage modifiable route for the synthesis of dysidavarone analogs for further anti-cancer activity evaluation.
基金the National Natural Science Foundation of China(Grant No.21736008)the National Key Research and Development Program of China(Grant No.2018YFB0604803).
文摘Methanol to aromatics produces multiple products,resulting in a limited selectivity of xylene.Aromatics upgrading is an effective way to produce more valuable xylene product,and different feed ratios generate discrepant product distributions.This work integrates the aromatics separation with toluene disproportionation,transalkylation of toluene and trimethylbenzene,and isomerization of xylene and trimethylbenzene.Exergy and exergoeconomic analyses are conducted to give insights in the splitting ratios of benzene,toluene and heavy aromatics for aromatics upgrading.First,a detailed simulation model is developed in Aspen HYSYS.Then,300 splitting ratio sets of benzene and toluene for conversion are studied to investigate the process performances.The results indicate that there are different preferences for the splitting ratios of benzene and toluene in terms of exergy and exergoeconomic performances.The process generates lower total exergy destruction when the splitting ratio of toluene varies between 0.07 and 0.18,and that of benzene fluctuates between 0.55 and 0.6.Nevertheless,the process presents lower total product unit cost with the splitting ratio of toluene less than 0.18 and that of benzene fluctuating between 0.44 and 0.89.Besides,it is found that distillation is the biggest contributor to the total exergy destruction,accounting for 94.97%.
文摘为了探究微波预处理对油茶籽毛油抗氧化性的影响,了解油茶籽毛油中抗氧物质的变化规律。以油茶籽仁为原料,研究微波预处理后油清除自由基能力及油中抗氧物质的含量及其抗氧能力变化。结果表明,微波预处理对油茶籽毛油抗氧化能力有显著影响。在700 W 20 min处油茶籽毛油DPPH含量有最大值,为(337.08±6.07)μg TE/g。微波预处理后总酚含量呈现上升趋势,含量最高为700 W 20 min处,为(193.04±9.38)μg GAE/g。其ABTS阳离子自由基清除能力小于FRAP还原能力。美拉德产物含量经微波预处理后变化显著,5-羟甲基糠醛(5-HMF)在560 W 20 min处有最大值,为(26.76±1.46)μg/g,丙酮醛(MGO)和3-脱氧葡萄糖醛酮(3-DG)在700 W 20 min处有最大值,分别为(13.60±2.18)、(75.46±3.79)μg/g。
基金Project supported by National Natural Science Foundation(No. 69882002) and "973" project (No. G1999035805)
文摘It is proved that if G is a (+1)-colorable graph, so are the graphs G×Pn and C×Cn, where Pn and Cn are respectively the path and cycle with n vertices, and the maximum edge degree of the graph. The exact chromatic numbers of the product graphs and are also presented. Thus the total coloring conjecture is proved to be true for many other graphs.
基金supported by the Program for Changjiang Scholars and Innovative Research Team in University (IRT13095)Natural Science Foundation of China (20925205, 21332007)
文摘Structure units containing all-carbon quaternary stereogenic center are found in many bioactive natural products. However, enantioselective construction of this type of structure units has been a formidable challenge for synthetic community due to the steric hindrance enforced by all-carbon quatemary stereocenters. In this review, we present the achievements made by Chinese scientists in the area of asymmetric synthesis of all-carbon quaternary stereocenters in natural products during the past two years.
文摘Natural product mayamycin is the first example in the angucycline class featuring a C-glycoside linkage at the C5-position of the benz[a]anthracenone core with remarkable biological activities. We successfully synthesized the two retrosynthetic fragments, but found that the final C-glycosylation did not occur. Alternatively, an A-ring satu- rated aglycon was prepared, but the proposed C-glycosylation still did not proceed. Finally, a simplified substrate was used and the subsequent C-glycosylation went through smoothly, giving a two-ring less analogue of mayamy- cin.
文摘A novel cyclic prenylated phenylpropanoid, pondaplin 1, was first synthesized in 26% overall yields through an expeditious route (7 steps) that employed highly regio- and stereoselective phenyltellurenylation to arylacetylene and palladium (II) chloride-catalyzed carbonylation of hydroxy styryl phenyl telluride as key steps.
基金This work was supported by the National Natural Science Foundation of China(Nos.21732005,21991114,and 21871189)and 111 Project(No.B18035).
文摘Asymmetric catalysis has continued to enable the preparation of optically active natural products over the past decade.This minireview summarizes progress in the catalytic enantioselective total synthesis of complex monoterpenoid indole alkaloids covering the reports from 2019 to June 2021.In particular,the generation of the key chiral stereogenic centers with metal catalysts and organocatalysts has been highlighted,showcasing the power of asymmetric catalysis protocols in accessing complex molecular architectures.
