BACKGROUND Combined spinal-epidural(CSE)anesthesia is the preferred anesthesia method for cesarean delivery.The use of an epidural catheter is essential for administering additional drugs intraoperatively and managing...BACKGROUND Combined spinal-epidural(CSE)anesthesia is the preferred anesthesia method for cesarean delivery.The use of an epidural catheter is essential for administering additional drugs intraoperatively and managing postoperative pain.However,the insertion of epidural catheters is associated with various complications,such as total spinal anesthesia,symptoms indicative of spinal nerve root irritation,and challenges in epidural catheter removal.CASE SUMMARY We present a case report of a challenging epidural catheter removal due to knotting.The lumbar computed tomography scan results revealed that the catheter formed a tight knot in the epidural space.We used a novel extubation method and successfully removed the catheter.CONCLUSION The operator can use opposite forces to"spiral"apart the spinal joints by positioning the patient's body in a specific position.The findings indicate that,when combined with imaging examination results,this method is effective for the removal of epidural catheters.展开更多
This paper gives the knotted picture of the unknown quantum state in the process of quantum teleportation and the surgical knotted operations of the unitary operators operated on the teleported quantum state.
Based on the previous work about the knotted pictures of quantum states, quantum logic gates and unitary transformations, this paper further gives the whole complete quantum measurement process of quantum teleportatio...Based on the previous work about the knotted pictures of quantum states, quantum logic gates and unitary transformations, this paper further gives the whole complete quantum measurement process of quantum teleportation from the viewpoint of knot theory.展开更多
By means of the method of torus knot theory, this paper gives the complete processes of obtaining the knotted pictures of four Bell b^es from the knotted pictures of four basic two qubit states.
This paper introduces the unified expression of four Bell bases and uses the composition operation in knot theory to obtain the knotted picture of unitary operators based on Pauli operators, and gives the knotted expr...This paper introduces the unified expression of four Bell bases and uses the composition operation in knot theory to obtain the knotted picture of unitary operators based on Pauli operators, and gives the knotted expressions of 12 inversion relations between the four Bell bases.展开更多
By means of the torus knot theory method, this paper presents the complete process of obtaining the knotted pictures of eight GHZ states on the surface of a trivial torus from the knotted pictures of eight basic three...By means of the torus knot theory method, this paper presents the complete process of obtaining the knotted pictures of eight GHZ states on the surface of a trivial torus from the knotted pictures of eight basic three-qubit states on the surface of a trivial torus. Thus, we obtain eight knotted pictures 121 linkage on the ordinary plane.展开更多
In this paper, a novel decomposition expression for the U（1） gauge field in liquid crystals （LCs） is derived. Using this decomposition expression and the b-mapping topological current theory, we investigate the to...In this paper, a novel decomposition expression for the U（1） gauge field in liquid crystals （LCs） is derived. Using this decomposition expression and the b-mapping topological current theory, we investigate the topological structure of the vortex lines in LCs in detail. A topological invariant, i.e., the Chern-Simons （CS） action for the knotted vortex lines is presented, and the CS action is shown to be the total sum of all the self-linking and linking numbers of the knot family. Moreover, it is pointed out that the CS action is preserved in the branch processes of the knotted vortex lines.展开更多
This paper briefly introduces the five types of the surgical operations in knot theory and obtains the expression of single qubit quantum logic gate in terms of these surgical operations.
In this paper,knotted objects (RS vortices) in the theory of topological phase singularity in electromagneticfield have been investigated in details.By using the Duan's topological current theory,we rewrite the to...In this paper,knotted objects (RS vortices) in the theory of topological phase singularity in electromagneticfield have been investigated in details.By using the Duan's topological current theory,we rewrite the topological currentform of RS vortices and use this topological current we reveal that the Hopf invariant of RS vortices is just the sum ofthe linking and self-linking numbers of the knotted RS vortices.Furthermore,the conservation of the Hopf invariant inthe splitting,the mergence and the intersection processes of knotted RS vortices is also discussed.展开更多
The composition and residue-residue interactions of knotted proteins, compared with those of other proteins, can provide considerable insight into the driver of the knots in proteins. In this paper, we calculate the p...The composition and residue-residue interactions of knotted proteins, compared with those of other proteins, can provide considerable insight into the driver of the knots in proteins. In this paper, we calculate the probabilities of 20 amino acids in 273 knotted entries from the Protein Data Bank （PDB）. The collection of 273 entries contains all knotted structures in the PDB, and it is not a subset. With an appropriate value of Re, the numbers of all residue residue contacts are counted in all 273 knotted structures. To make an accurate comparison, we count up to 9000 other entries from the PDB as well, and these entries spread over all sorts. In knotted structures, Leu occupies a maximal proportion of 9.62% among all 20 amino acids, and Leu, Phe, Trp, Gly, His, Gln, Asp, Lys and Pro may all play a more important role. Also, we analyse the effects of amino acid residues on the long-range contacts. We observe a larger average number of long-range contacts in the knotted structures than that in other ones, implying their important role in achieving the knots. Accordingly, the average number of short-range contacts becomes small when the structure becomes knotted because it depends mainly on the short-haul sequence of amino acids to form the short-range contact. In addition, the shape distribution of knotted proteins and the contrast with the other proteins are also presented. A comparison shows that the knots may make structures more globular because the average shape factor is 0.059 for the knotted proteins, which is only about 1/3 of the average shape factor for the other proteins.展开更多
The phase behaviour of polyethylene knotted ring chains is investigated by using molecular dynamics simulations. In this paper, we focus on the collapse of the polyethylene knotted ring chain, and also present the res...The phase behaviour of polyethylene knotted ring chains is investigated by using molecular dynamics simulations. In this paper, we focus on the collapse of the polyethylene knotted ring chain, and also present the results of linear and ring chains for comparison. At high temperatures, a fully extensive knot structure is observed. The mean-square radius of gyration per bond （S2）/（Nb2） and the shape factor （（δ＊） depend on not only the chain length but also the knot type. With temperature decreasing, chain collapse is observed, and the collapse temperature decreases with the chain length increasing. The actual collapse transition can be determined by the specific heat capacity Cv, and the knotted ring chain undergoes gas-liquid-solid-like transition directly. The phase transition of a knotted ring chain is only one-stage collapse, which is different from the polyethylene linear and ring chains. This investigation can provide some insights into the statistical properties of knotted polymer chains.展开更多
In this paper the influence of a knot on the structure of a polymethylene （PM） strand in the tensile process is investigated by using the steered molecular dynamics （SMD） method. The gradual increasing of end-to-e...In this paper the influence of a knot on the structure of a polymethylene （PM） strand in the tensile process is investigated by using the steered molecular dynamics （SMD） method. The gradual increasing of end-to-end distance, R, results in a tighter knot and a more stretched contour. That the break in a knotted rope almost invariably occurs at a point just outside the ＇entrance＇ to the knot, which has been shown in a good many experiments, is further theoretically verified in this paper through the calculation of some structural and thermodynamic parameters. Moreover, it is found that the analyses on bond length, torsion angle and strain energy can facilitate to the study of the localization and the size of a knot in the tensile process. The symmetries of torsion angles, bond lengths and bond angles in the knot result in the whole symmetry of the knot in microstructure, thereby adapting itself to the strain applied. Additionally, the statistical property of the force-dependent average knot size illuminates in detail the change in size of a knot with force f, and therefore the minimum size of the knot in the restriction of the potentials considered in this work for a PM chain is deduced. At the same time, the difference in response to uniaxial strain, between a knotted PM strand and an unknotted one is also investigated. The force-extension profile is easily obtained from the simulation. As expected, for a given f, the knotted chain has an R significantly smaller than that of an unknotted polymer. However, the scaled difference becomes less pronounced for larger values of N, and the results for longer chains approach those of the unknotted chains.展开更多
Optical vortices as topological objects exist ubiquitously in nature.In this paper,by making use of the Duan's topological current theory,we investigate the topology in the closed and knotted optical vortices.The ...Optical vortices as topological objects exist ubiquitously in nature.In this paper,by making use of the Duan's topological current theory,we investigate the topology in the closed and knotted optical vortices.The topological inner structure of the optical vortices are obtained,and the linking of the knotted optical vortices is also given.展开更多
In order to achieve an innovative strategy to renew the biomass of Phanerochaete chrysosporium in an immobilized growth system which can maintain white-rot fungi biomass, a novel knotted cotton-thread carrier was desi...In order to achieve an innovative strategy to renew the biomass of Phanerochaete chrysosporium in an immobilized growth system which can maintain white-rot fungi biomass, a novel knotted cotton-thread carrier was designed and made. By using a high-speed stirring apparatus under the conditions of 1400 r/min stirring speed for 6 min, mycelia immobilized on the knotted cotton-thread carriers were exfoliated completely and homogenized to a proper size. Furthermore, the homogenized mycelia from the immobilized mycelia can resume their growth on the knotted cotton-thread carriers in agitated flask cultures. The average regrowth biomass on the new carriers and the reused carriers was 0.0171 g/carrier and 0.0314 g/carrier, respectively. It proves that the knotted cotton-thread carrier performs perfectly in homogening the immobilized mycelia to achieve the biomass renewal of P. chrysosporium in an immobilized growth system.展开更多
This study evaluated the hydrodynamic forces produced by whole panels of hand-made(geometrically different)rope meshes typically found in midwater trawls.Experimental treatments included both knotted and knotless mesh...This study evaluated the hydrodynamic forces produced by whole panels of hand-made(geometrically different)rope meshes typically found in midwater trawls.Experimental treatments included both knotted and knotless meshes constructed of helix composite ropes,conventional braided nylon(PA)ropes,and twisted polyethylene(PE)ropes.Direct measurement of lift(L)and drag(D)forces were conducted using controlled flume tank experiments on panels oriented at 21°relative to the flow.For knotted netting,our results showed that the hydrodynamic forces(L and D)were statistically higher for helix ropes compared to conventional ropes of the same diameter.For knotless netting constructed of helix ropes,our primary finding is that the arrangement of helix ropes(S and Z lay)in individual meshes significantly affects the resulting D and Cd of whole netting panels.Arranging the mesh bars in the S-Z-S-Z lay pattern exhibited 29%and 32%lower drag(D)compared to S–S–S–S and S–S-Z-Z lay meshes,respectively.We also use computational fluid dynamics(CFD)to characterize the finescale flow-field around helix and conventional ropes.The resulting streamlines and pressure contours provide a functional explanation for the empirical measurements collected in the flume tank.These results can be useful in informing the design of midwater trawls.展开更多
[Objectives]To investigate the chemical composition,antioxidant property,and nematicidal activity of Cucumis metuliferus and establish a theoretical foundation for the development of botanical nematicides.[Methods]The...[Objectives]To investigate the chemical composition,antioxidant property,and nematicidal activity of Cucumis metuliferus and establish a theoretical foundation for the development of botanical nematicides.[Methods]The compounds were isolated and purified using silica gel,reversed-phase medium,low-pressure gel Sephadex LH-20 column chromatography,and preparative high-performance liquid chromatography.Their identification was based on physicochemical properties,various spectral analyses,and data reported in the literature.Subsequently,the nematicidal and antioxidant activities of the isolated compounds were evaluated.[Results]A total of four compounds were isolated from C.metuliferus,which were identified as isovitexin-2″-O-glucoside(compound 1),9E,11E-(13-oxo)tridecadienoic acid(compound 2),2E,4E-tridecadienedioic acid(compound 3),and 9E,11E-(13-hydroxy)tridecadienoic acid(compound 4).Compound 1 demonstrated a notable degree of antioxidant activity,achieving a DPPH scavenging rate of 49.40%at a mass concentration of 1 mg/mL.Additionally,compounds 1,3,and 4 exhibited varying levels of nematicidal activity.Specifically,compound 1 displayed strong nematicidal activity at a concentration of 2.0 mg/mL,resulting in a mortality rate of 90.5%against nematodes.Furthermore,compounds 3 and 4 achieved a mortality rate of 100%against nematodes at a concentration of 0.25 mg/mL.[Conclusions]This study reports the first isolation of four compounds:isovitexin-2″-O-glucoside,9E,11E-(13-oxo)tridecadienoic acid,2E,4E-tridecadienedioic acid,and 9E,11E-(13-hydroxy)tridecadienoic acid from C.metuliferus.Notably,2E,4E-tridecadienedioic acid and 9E,11E-(13-oxo)tridecadienoic acid are identified as novel natural products.Among these compounds,isovitexin-2″-O-glucoside,9E,11E-(13-oxo)tridecadienoic acid,and 9E,11E-(13-hydroxy)tridecadienoic acid exhibit nematicidal activity,whereas isovitexin-2″-O-glucoside demonstrates antioxidant properties.展开更多
In this work,Langevin dynamics simulations were carried out to thoroughly investigate the swapping process of composite knots under tension in a cuboid nanochannel.From our analysis,the free energy profiles of knot sw...In this work,Langevin dynamics simulations were carried out to thoroughly investigate the swapping process of composite knots under tension in a cuboid nanochannel.From our analysis,the free energy profiles of knot swapping under different conditions were extracted from the overall probability distribution of the relative distance between the centers of composite knots.In addition,the impact of the stretching force,confinement size,and bending stiffness on the free energy profiles was directly identified.Especially,the influence of topology structure is for the first time reported.The increasing stretching force in a fixed confinement or the confinement size under a constant stretching force does not alter their respective equilibrium populations at the separate state and the entangled state.In contrast,a bending stiffness larger than 15 enhanced the formation of the entangled state.The topology structure of the 51knot,which was different from the 52knot,resulted in forming a metastable state in the free energy profiles.The increasing stretching forces yielded an enhancement of the following free energy barrier.展开更多
文摘BACKGROUND Combined spinal-epidural(CSE)anesthesia is the preferred anesthesia method for cesarean delivery.The use of an epidural catheter is essential for administering additional drugs intraoperatively and managing postoperative pain.However,the insertion of epidural catheters is associated with various complications,such as total spinal anesthesia,symptoms indicative of spinal nerve root irritation,and challenges in epidural catheter removal.CASE SUMMARY We present a case report of a challenging epidural catheter removal due to knotting.The lumbar computed tomography scan results revealed that the catheter formed a tight knot in the epidural space.We used a novel extubation method and successfully removed the catheter.CONCLUSION The operator can use opposite forces to"spiral"apart the spinal joints by positioning the patient's body in a specific position.The findings indicate that,when combined with imaging examination results,this method is effective for the removal of epidural catheters.
文摘This paper gives the knotted picture of the unknown quantum state in the process of quantum teleportation and the surgical knotted operations of the unitary operators operated on the teleported quantum state.
文摘Based on the previous work about the knotted pictures of quantum states, quantum logic gates and unitary transformations, this paper further gives the whole complete quantum measurement process of quantum teleportation from the viewpoint of knot theory.
文摘By means of the method of torus knot theory, this paper gives the complete processes of obtaining the knotted pictures of four Bell b^es from the knotted pictures of four basic two qubit states.
文摘This paper introduces the unified expression of four Bell bases and uses the composition operation in knot theory to obtain the knotted picture of unitary operators based on Pauli operators, and gives the knotted expressions of 12 inversion relations between the four Bell bases.
文摘By means of the torus knot theory method, this paper presents the complete process of obtaining the knotted pictures of eight GHZ states on the surface of a trivial torus from the knotted pictures of eight basic three-qubit states on the surface of a trivial torus. Thus, we obtain eight knotted pictures 121 linkage on the ordinary plane.
基金The project supported by National Natural Science Foundation of China under Grant No. 10475034 and the Doctor Education Fund of the Educational Department of China.Acknowledgments It is a great pleasure to thank Dr. Y.X. Liu and Dr. Z.G. Huang for many useful discussions.
文摘In this paper, a novel decomposition expression for the U（1） gauge field in liquid crystals （LCs） is derived. Using this decomposition expression and the b-mapping topological current theory, we investigate the topological structure of the vortex lines in LCs in detail. A topological invariant, i.e., the Chern-Simons （CS） action for the knotted vortex lines is presented, and the CS action is shown to be the total sum of all the self-linking and linking numbers of the knot family. Moreover, it is pointed out that the CS action is preserved in the branch processes of the knotted vortex lines.
文摘This paper briefly introduces the five types of the surgical operations in knot theory and obtains the expression of single qubit quantum logic gate in terms of these surgical operations.
基金supported by National Natural Science Foundation of China and the Cuiying Programme of Lanzhou University
文摘In this paper,knotted objects (RS vortices) in the theory of topological phase singularity in electromagneticfield have been investigated in details.By using the Duan's topological current theory,we rewrite the topological currentform of RS vortices and use this topological current we reveal that the Hopf invariant of RS vortices is just the sum ofthe linking and self-linking numbers of the knotted RS vortices.Furthermore,the conservation of the Hopf invariant inthe splitting,the mergence and the intersection processes of knotted RS vortices is also discussed.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 20574052 and 20774066)the Program for New Century Excellent Talents in University, China (Grant No NCET-05-0538)the Natural Science Foundation of Zhejiang Province, China (Grant No R404047)
文摘The composition and residue-residue interactions of knotted proteins, compared with those of other proteins, can provide considerable insight into the driver of the knots in proteins. In this paper, we calculate the probabilities of 20 amino acids in 273 knotted entries from the Protein Data Bank （PDB）. The collection of 273 entries contains all knotted structures in the PDB, and it is not a subset. With an appropriate value of Re, the numbers of all residue residue contacts are counted in all 273 knotted structures. To make an accurate comparison, we count up to 9000 other entries from the PDB as well, and these entries spread over all sorts. In knotted structures, Leu occupies a maximal proportion of 9.62% among all 20 amino acids, and Leu, Phe, Trp, Gly, His, Gln, Asp, Lys and Pro may all play a more important role. Also, we analyse the effects of amino acid residues on the long-range contacts. We observe a larger average number of long-range contacts in the knotted structures than that in other ones, implying their important role in achieving the knots. Accordingly, the average number of short-range contacts becomes small when the structure becomes knotted because it depends mainly on the short-haul sequence of amino acids to form the short-range contact. In addition, the shape distribution of knotted proteins and the contrast with the other proteins are also presented. A comparison shows that the knots may make structures more globular because the average shape factor is 0.059 for the knotted proteins, which is only about 1/3 of the average shape factor for the other proteins.
基金supported by the National Natural Science Foundation of China (Grant Nos. 20574052,20774066,20974081,and 20934004)the Program for New Century Excellent Talents in University of the Ministry of Education of China (Grant No. NCET-05-0538)the Ph.D. Program Foundation of the Ministry of Education of China (Grant No. 20090101110002)
文摘The phase behaviour of polyethylene knotted ring chains is investigated by using molecular dynamics simulations. In this paper, we focus on the collapse of the polyethylene knotted ring chain, and also present the results of linear and ring chains for comparison. At high temperatures, a fully extensive knot structure is observed. The mean-square radius of gyration per bond （S2）/（Nb2） and the shape factor （（δ＊） depend on not only the chain length but also the knot type. With temperature decreasing, chain collapse is observed, and the collapse temperature decreases with the chain length increasing. The actual collapse transition can be determined by the specific heat capacity Cv, and the knotted ring chain undergoes gas-liquid-solid-like transition directly. The phase transition of a knotted ring chain is only one-stage collapse, which is different from the polyethylene linear and ring chains. This investigation can provide some insights into the statistical properties of knotted polymer chains.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 20274040,20574052 and 20774066)the Program for New Century Excellent Talents in University,China (Grant No NCET-05-0538)the Natural Science Foundation of Zhejiang Province,China (Grant No R404047)
文摘In this paper the influence of a knot on the structure of a polymethylene （PM） strand in the tensile process is investigated by using the steered molecular dynamics （SMD） method. The gradual increasing of end-to-end distance, R, results in a tighter knot and a more stretched contour. That the break in a knotted rope almost invariably occurs at a point just outside the ＇entrance＇ to the knot, which has been shown in a good many experiments, is further theoretically verified in this paper through the calculation of some structural and thermodynamic parameters. Moreover, it is found that the analyses on bond length, torsion angle and strain energy can facilitate to the study of the localization and the size of a knot in the tensile process. The symmetries of torsion angles, bond lengths and bond angles in the knot result in the whole symmetry of the knot in microstructure, thereby adapting itself to the strain applied. Additionally, the statistical property of the force-dependent average knot size illuminates in detail the change in size of a knot with force f, and therefore the minimum size of the knot in the restriction of the potentials considered in this work for a PM chain is deduced. At the same time, the difference in response to uniaxial strain, between a knotted PM strand and an unknotted one is also investigated. The force-extension profile is easily obtained from the simulation. As expected, for a given f, the knotted chain has an R significantly smaller than that of an unknotted polymer. However, the scaled difference becomes less pronounced for larger values of N, and the results for longer chains approach those of the unknotted chains.
基金supported by National Natural Science Foundation of China
文摘Optical vortices as topological objects exist ubiquitously in nature.In this paper,by making use of the Duan's topological current theory,we investigate the topology in the closed and knotted optical vortices.The topological inner structure of the optical vortices are obtained,and the linking of the knotted optical vortices is also given.
基金Supported by the National Natural Science Foundation of China (Grant No. 206770 33)
文摘In order to achieve an innovative strategy to renew the biomass of Phanerochaete chrysosporium in an immobilized growth system which can maintain white-rot fungi biomass, a novel knotted cotton-thread carrier was designed and made. By using a high-speed stirring apparatus under the conditions of 1400 r/min stirring speed for 6 min, mycelia immobilized on the knotted cotton-thread carriers were exfoliated completely and homogenized to a proper size. Furthermore, the homogenized mycelia from the immobilized mycelia can resume their growth on the knotted cotton-thread carriers in agitated flask cultures. The average regrowth biomass on the new carriers and the reused carriers was 0.0171 g/carrier and 0.0314 g/carrier, respectively. It proves that the knotted cotton-thread carrier performs perfectly in homogening the immobilized mycelia to achieve the biomass renewal of P. chrysosporium in an immobilized growth system.
基金This project was part of Module H of the Ocean Frontier Institute,funded by the Canada First Research Excellence Fund.
文摘This study evaluated the hydrodynamic forces produced by whole panels of hand-made(geometrically different)rope meshes typically found in midwater trawls.Experimental treatments included both knotted and knotless meshes constructed of helix composite ropes,conventional braided nylon(PA)ropes,and twisted polyethylene(PE)ropes.Direct measurement of lift(L)and drag(D)forces were conducted using controlled flume tank experiments on panels oriented at 21°relative to the flow.For knotted netting,our results showed that the hydrodynamic forces(L and D)were statistically higher for helix ropes compared to conventional ropes of the same diameter.For knotless netting constructed of helix ropes,our primary finding is that the arrangement of helix ropes(S and Z lay)in individual meshes significantly affects the resulting D and Cd of whole netting panels.Arranging the mesh bars in the S-Z-S-Z lay pattern exhibited 29%and 32%lower drag(D)compared to S–S–S–S and S–S-Z-Z lay meshes,respectively.We also use computational fluid dynamics(CFD)to characterize the finescale flow-field around helix and conventional ropes.The resulting streamlines and pressure contours provide a functional explanation for the empirical measurements collected in the flume tank.These results can be useful in informing the design of midwater trawls.
基金Supported by Natural Science Foundation Project of Xinjiang Uygur Autonomous Region(2021D01B59)Youth Science and Technology Backbone Project of Xinjiang Academy of Agricultural Sciences(XJNKQ-2021011)+2 种基金General Program of Hainan Natural Science Foundation(319MS109)Major Science and Technology Program of Hainan Province(ZDKJ2021005)Specific Research Fund of the Innovation Platform for Academicians of Hainan Province(YSPTZX202141).
文摘[Objectives]To investigate the chemical composition,antioxidant property,and nematicidal activity of Cucumis metuliferus and establish a theoretical foundation for the development of botanical nematicides.[Methods]The compounds were isolated and purified using silica gel,reversed-phase medium,low-pressure gel Sephadex LH-20 column chromatography,and preparative high-performance liquid chromatography.Their identification was based on physicochemical properties,various spectral analyses,and data reported in the literature.Subsequently,the nematicidal and antioxidant activities of the isolated compounds were evaluated.[Results]A total of four compounds were isolated from C.metuliferus,which were identified as isovitexin-2″-O-glucoside(compound 1),9E,11E-(13-oxo)tridecadienoic acid(compound 2),2E,4E-tridecadienedioic acid(compound 3),and 9E,11E-(13-hydroxy)tridecadienoic acid(compound 4).Compound 1 demonstrated a notable degree of antioxidant activity,achieving a DPPH scavenging rate of 49.40%at a mass concentration of 1 mg/mL.Additionally,compounds 1,3,and 4 exhibited varying levels of nematicidal activity.Specifically,compound 1 displayed strong nematicidal activity at a concentration of 2.0 mg/mL,resulting in a mortality rate of 90.5%against nematodes.Furthermore,compounds 3 and 4 achieved a mortality rate of 100%against nematodes at a concentration of 0.25 mg/mL.[Conclusions]This study reports the first isolation of four compounds:isovitexin-2″-O-glucoside,9E,11E-(13-oxo)tridecadienoic acid,2E,4E-tridecadienedioic acid,and 9E,11E-(13-hydroxy)tridecadienoic acid from C.metuliferus.Notably,2E,4E-tridecadienedioic acid and 9E,11E-(13-oxo)tridecadienoic acid are identified as novel natural products.Among these compounds,isovitexin-2″-O-glucoside,9E,11E-(13-oxo)tridecadienoic acid,and 9E,11E-(13-hydroxy)tridecadienoic acid exhibit nematicidal activity,whereas isovitexin-2″-O-glucoside demonstrates antioxidant properties.
基金The National Natural Science Foundation of China under Grant Nos.11864006,11874309,12164007,and 12204118。
文摘In this work,Langevin dynamics simulations were carried out to thoroughly investigate the swapping process of composite knots under tension in a cuboid nanochannel.From our analysis,the free energy profiles of knot swapping under different conditions were extracted from the overall probability distribution of the relative distance between the centers of composite knots.In addition,the impact of the stretching force,confinement size,and bending stiffness on the free energy profiles was directly identified.Especially,the influence of topology structure is for the first time reported.The increasing stretching force in a fixed confinement or the confinement size under a constant stretching force does not alter their respective equilibrium populations at the separate state and the entangled state.In contrast,a bending stiffness larger than 15 enhanced the formation of the entangled state.The topology structure of the 51knot,which was different from the 52knot,resulted in forming a metastable state in the free energy profiles.The increasing stretching forces yielded an enhancement of the following free energy barrier.
