In this theoretical study,we investigate the generation of second harmonics(SH)during the interaction of a laser beam with a metallic nanoparticle(MNP)trimer.Utilizing a classical electrodynamics framework,we explore ...In this theoretical study,we investigate the generation of second harmonics(SH)during the interaction of a laser beam with a metallic nanoparticle(MNP)trimer.Utilizing a classical electrodynamics framework,we explore the nonlinear interactions between the laser beam fields and nanoparticles(NPs),accounting for dipole-dipole interactions among the particles.Analytical expressions are derived to quantify the impact of these interactions on SH radiation power for two distinct polarizations of the laser beam.Our findings indicate that when the laser electric field is aligned parallel to the trimer's symmetry axis,there is a significant enhancement in SH radiation power compared to a single non-interacting NP,accompanied by a red-shift in the plasmon resonance peak.Conversely,when the laser electric field is perpendicular to the trimer axis,the SH radiation power from each NP decreases,and the plasmon resonance peak experiences a blue-shift.Additionally,we examine the influence of particle size and interparticle separation on SH generation.These results provide valuable insights into the role of interparticle interactions in enhancing nonlinear optical processes in NP assemblies,with potential implications for the design of nanophotonic devices.展开更多
Propylene,a readily accessible and economically viable light olefin,has garnered substantial interest for its potential conversion into valuable higher olefins through oligomerization processes.The distribution of pro...Propylene,a readily accessible and economically viable light olefin,has garnered substantial interest for its potential conversion into valuable higher olefins through oligomerization processes.The distribution of products is profoundly influenced by the catalyst structure.In this study,Fe_(2)O_(3)-doped NiSO_(4)/Al_(2)O_(3) catalysts have been meticulously developed to facilitate the selective trimerization of propylene under mild conditions.Significantly,the 0.25Fe_(2)O_(3)-NiSO_(4)/Al_(2)O_(3) catalyst demonstrates an enhanced reaction rate(48.5 mmol_(C3)/(g_(cat).·h)),alongside a high yield of C9(~32.2%),significantly surpassing the performance of the NiSO_(4)/Al_(2)O_(3) catalyst(C9:~24.1%).The incorporation of Fe_(2)O_(3) modifies the migration process of sulfate ions,altering the Lewis acidity of the electron-deficient Ni and Fe sites on the catalyst and resulting a shift in product distribution from a Schulz-Flory distribution to a Poisson distribution.This shift is primarily ascribed to the heightened energy barrier for theβ-H elimination reaction in the C6 alkyl intermediates on the doped catalyst,further promoting polymerization to yield a greater quantity of Type II C9.Furthermore,the validation of the Cossee-Arlman mechanism within the reaction pathway has been confirmed.It is noteworthy that the 0.25Fe_(2)O_(3)-NiSO_(4)/Al_(2)O_(3) catalyst exhibits remarkable stability exceeding 80 h in the selective trimerization of propylene.These research findings significantly enhance our understanding of the mechanisms underlying olefin oligomerization reactions and provide invaluable insights for the development of more effective catalysts.展开更多
As an increasingly used alternative to perfluorooctanoic acid(PFOA),hexafluoropropylene oxide trimer acid(HFPO-TA)has been widely detected in global water environments.However,little is known regarding its toxic effec...As an increasingly used alternative to perfluorooctanoic acid(PFOA),hexafluoropropylene oxide trimer acid(HFPO-TA)has been widely detected in global water environments.However,little is known regarding its toxic effects on cardiovascular development.Here,zebrafish embryos were treated with egg water containing 0,60,120,or 240 mg/L HFPO-TA.Results showed that HFPO-TA treatment led to a significant reduction in both larval survival percentage and heart rate.Furthermore,HFPO-TA exposure caused severe pericardial edema and elongation of the sinus venous to bulbus arteriosus distance(SV-BA)in Tg(myl7:GFP)transgenic larvae,disrupting the expression of genes involved in heart development and thus causing abnormal heart looping.Obvious sprouting angiogenesis was observed in the 120 and 240 mg/L exposed Tg(fli:GFP)transgenic larvae.HFPO-TA treatment also impacted the mRNA levels of genes involved in the vascular endothelial growth factor(VEGF)pathway and embryonic vascular development.HFPO-TA exposure significantly decreased erythrocyte number in Tg(gata1:DsRed)transgenic embryos and influenced gene expression associated with the heme metabolism pathway.HFPO-TA also induced oxidative stress and altered the transcriptional levels of genes related to cell cycle and apoptosis,inhibiting cell proliferation while promoting apoptosis.Therefore,HFPO-TA exposure may induce abnormal development of the cardiovascular and hematopoietic systems in zebrafish embryos,suggesting it may not be a suitable or safe alternative for PFOA.展开更多
Citrinsorbicillin A(1),a novel homotrimeric sorbicillinoid,along with two new monomers citrinsor-bicillins B(2)and C(3),were isolated from the Coptis chinensis endophyte Trichoderma citrinoviride HT-9 by liquid chroma...Citrinsorbicillin A(1),a novel homotrimeric sorbicillinoid,along with two new monomers citrinsor-bicillins B(2)and C(3),were isolated from the Coptis chinensis endophyte Trichoderma citrinoviride HT-9 by liquid chromatograph mass spectrometer(LC-MS)-guided strategy.1 was the first trimeric-example from terrestrial fungi,which possessed a unique carbon skeleton with two bicyclo[2.2.2]octanedione ring connected through an enolated carbon forming by[4+2]cycloaddition.Their structures were elucidated by spectroscopic analysis and X-ray diffraction.1 exhibited moderate cytotoxicity against human colon cancer HT29 cells,and it induced significant cell cycle arrest by reducing the protein expression of cyclin D1.展开更多
Five novel(9,10-dihydro)phenanthrene and bibenzyl trimers,as well as two previously identified biphenanthrenes and bibenzyls,were isolated from the tubers of Bletilla striata.Their structures were elucidated through c...Five novel(9,10-dihydro)phenanthrene and bibenzyl trimers,as well as two previously identified biphenanthrenes and bibenzyls,were isolated from the tubers of Bletilla striata.Their structures were elucidated through comprehensive analyses of NMR and HRESIMS spectroscopic data.The absolute configurations of these compounds were determined by calculating rotational energy barriers and comparison of experimental and calculated ECD curves.Compounds 5b and 6 exhibited inhibitory effects on LPS-induced NO production in BV-2 cells,with IC_(50) values of 12.59±0.40 and 15.59±0.83μmol·L^(-1),respectively.A mechanistic study suggested that these compounds may attenuate neuroinflammation by reducing the activation of the AKT/IκB/NF-κB signaling pathway.Additionally,compounds 3a,6,and 7 demonstrated significant PTP1B inhibitory activities,with IC_(50) values of 1.52±0.34,1.39±0.11,and 1.78±0.01μmol·L^(-1),respectively.Further investigation revealed that compound 3a might inhibit LPS-induced PTP1B overexpression and NF-κB activation,thereby mitigating the neuroinflammatory response in BV-2 cells.展开更多
One new A - type proanthocyanidin trimer, lindetannin trimer, was isolated from the stems of Lindera aggregata (Sims) Kosterm.. Its structure was elucidated by spectral and chemical methods.
From an aqueous extract of“tian ma”(the steamed and dried rhizomes of Gastrodia elata),ten new compounds gastrodiben-zins A−D(1−4)and gastrotribenzins A−F(5−10),along with known analogues(11−20),having structure fea...From an aqueous extract of“tian ma”(the steamed and dried rhizomes of Gastrodia elata),ten new compounds gastrodiben-zins A−D(1−4)and gastrotribenzins A−F(5−10),along with known analogues(11−20),having structure features coupling between two and three p-hydroxybenzyl-derived units via carbon-and/or ether-bonds,were isolated and characterized by spectroscopic data analysis.Meanwhile,the new compounds 5a,6a,8a,22,and 23,as well as the known derivatives 13a,14a,15,17−21,24,25,and p-hydroxybenzyl aldehyde were isolated and identified from a refluxed aqueous solution of p-hydroxybenzyl alcohol.Methylation of 5a and 6a in methanol and ethylation of 6a,8a,13a,and 14a in ethanol produced 5 and 6 and 7,8,13,and 14,respectively.using ultra-performance liquid chromatography high-resolution electrospray ioniza-tion mass spectrometry(UPLC-HRESIMS)analysis of the refluxed solutions of p-hydroxybenzyl alcohol and the refluxed extracts of the fresh G.elata rhizome and“tian ma”extracts indicated consistent production and variation of the dimeric and trimeric derivatives of p-hydroxybenzyl alcohol upon extracting solvents and refluxing time.In various assays,the dimeric and trimeric derivatives showed more potent activities than p-hydroxybenzyl alcohol itself and gastrodin,which are the main known active constituents of“tian ma”.These results revealed for the first time that the more effective dimers and trimers can be produced through condensation of the co-occurring p-hydroxybenzyl alcohol during processing and decocting of the G.elata rhizomes,demonstrating insights into medicinal chemistry behind application protocols of traditional Chinese medicines.展开更多
A trimeric porous coordination framework [Ni_3(TPTC)(IN)_2(μ_2-H_2O)_2(CH_3OH)_2)]n· x(solvents)(1, TPTC = terphenyl-3,3?,5,5??-tetracarboxylic acid, IN = isonicotinic acid) was synthesized and characterized by ...A trimeric porous coordination framework [Ni_3(TPTC)(IN)_2(μ_2-H_2O)_2(CH_3OH)_2)]n· x(solvents)(1, TPTC = terphenyl-3,3?,5,5??-tetracarboxylic acid, IN = isonicotinic acid) was synthesized and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, single-crystal and powder X-ray diffraction. It crystallizes in monoclinic space group C2/c with a = 33739(12), b = 14.820(5), c = 13.568(5) ?, β = 97.388(6)o, V = 6728(4) ?3, Z = 4, Mr = 965.35, Dc = 0.953 g·cm^(-3), F(000) = 1955.5, μ = 0.881 mm^(–1), GOOF = 1.072, the final R = 0.0859 and w R = 0.2424 for 5284 observed reflections with I > 2σ(I). The structure of 1 is constructed from the linkage of trinuclear {Ni_3} second building units through TPTC and IN spacers, forming a 4,8-connected network of Schl?fli symbol {32.42.52}{34.46.58.68.72}. The CO2 uptake values for 1 are 97.9 m^2·g^(-1) at 273 K and 66.2 m^2·g^(-1) at 298 K, while its N_2 adsorption values are 8.5 m^2·g^(-1) at 273 K and 4.9 m^2·g^(-1) at 298 K, respectively. These results show that 1 has high CO_2/N_2 adsorption selectivity at ambient conditions.展开更多
文摘In this theoretical study,we investigate the generation of second harmonics(SH)during the interaction of a laser beam with a metallic nanoparticle(MNP)trimer.Utilizing a classical electrodynamics framework,we explore the nonlinear interactions between the laser beam fields and nanoparticles(NPs),accounting for dipole-dipole interactions among the particles.Analytical expressions are derived to quantify the impact of these interactions on SH radiation power for two distinct polarizations of the laser beam.Our findings indicate that when the laser electric field is aligned parallel to the trimer's symmetry axis,there is a significant enhancement in SH radiation power compared to a single non-interacting NP,accompanied by a red-shift in the plasmon resonance peak.Conversely,when the laser electric field is perpendicular to the trimer axis,the SH radiation power from each NP decreases,and the plasmon resonance peak experiences a blue-shift.Additionally,we examine the influence of particle size and interparticle separation on SH generation.These results provide valuable insights into the role of interparticle interactions in enhancing nonlinear optical processes in NP assemblies,with potential implications for the design of nanophotonic devices.
文摘Propylene,a readily accessible and economically viable light olefin,has garnered substantial interest for its potential conversion into valuable higher olefins through oligomerization processes.The distribution of products is profoundly influenced by the catalyst structure.In this study,Fe_(2)O_(3)-doped NiSO_(4)/Al_(2)O_(3) catalysts have been meticulously developed to facilitate the selective trimerization of propylene under mild conditions.Significantly,the 0.25Fe_(2)O_(3)-NiSO_(4)/Al_(2)O_(3) catalyst demonstrates an enhanced reaction rate(48.5 mmol_(C3)/(g_(cat).·h)),alongside a high yield of C9(~32.2%),significantly surpassing the performance of the NiSO_(4)/Al_(2)O_(3) catalyst(C9:~24.1%).The incorporation of Fe_(2)O_(3) modifies the migration process of sulfate ions,altering the Lewis acidity of the electron-deficient Ni and Fe sites on the catalyst and resulting a shift in product distribution from a Schulz-Flory distribution to a Poisson distribution.This shift is primarily ascribed to the heightened energy barrier for theβ-H elimination reaction in the C6 alkyl intermediates on the doped catalyst,further promoting polymerization to yield a greater quantity of Type II C9.Furthermore,the validation of the Cossee-Arlman mechanism within the reaction pathway has been confirmed.It is noteworthy that the 0.25Fe_(2)O_(3)-NiSO_(4)/Al_(2)O_(3) catalyst exhibits remarkable stability exceeding 80 h in the selective trimerization of propylene.These research findings significantly enhance our understanding of the mechanisms underlying olefin oligomerization reactions and provide invaluable insights for the development of more effective catalysts.
基金supported by the Ministry of Science and Technology of China(Nos.2021YFA1101300 and 2020YFA0112500)the National Key R&D Program of China(2018YFA0801000)the National Natural Science Foundation of China(No.32170853)。
文摘As an increasingly used alternative to perfluorooctanoic acid(PFOA),hexafluoropropylene oxide trimer acid(HFPO-TA)has been widely detected in global water environments.However,little is known regarding its toxic effects on cardiovascular development.Here,zebrafish embryos were treated with egg water containing 0,60,120,or 240 mg/L HFPO-TA.Results showed that HFPO-TA treatment led to a significant reduction in both larval survival percentage and heart rate.Furthermore,HFPO-TA exposure caused severe pericardial edema and elongation of the sinus venous to bulbus arteriosus distance(SV-BA)in Tg(myl7:GFP)transgenic larvae,disrupting the expression of genes involved in heart development and thus causing abnormal heart looping.Obvious sprouting angiogenesis was observed in the 120 and 240 mg/L exposed Tg(fli:GFP)transgenic larvae.HFPO-TA treatment also impacted the mRNA levels of genes involved in the vascular endothelial growth factor(VEGF)pathway and embryonic vascular development.HFPO-TA exposure significantly decreased erythrocyte number in Tg(gata1:DsRed)transgenic embryos and influenced gene expression associated with the heme metabolism pathway.HFPO-TA also induced oxidative stress and altered the transcriptional levels of genes related to cell cycle and apoptosis,inhibiting cell proliferation while promoting apoptosis.Therefore,HFPO-TA exposure may induce abnormal development of the cardiovascular and hematopoietic systems in zebrafish embryos,suggesting it may not be a suitable or safe alternative for PFOA.
基金supported by the National Natural Science Foundation of China(No.82003629)the Natural Science Foundation of Chongqing(No.cstc2021jcyj-msxmX0975)the Open Project of State Key Laboratory of Natural Medicines(No.SKLNMKF202304).
文摘Citrinsorbicillin A(1),a novel homotrimeric sorbicillinoid,along with two new monomers citrinsor-bicillins B(2)and C(3),were isolated from the Coptis chinensis endophyte Trichoderma citrinoviride HT-9 by liquid chromatograph mass spectrometer(LC-MS)-guided strategy.1 was the first trimeric-example from terrestrial fungi,which possessed a unique carbon skeleton with two bicyclo[2.2.2]octanedione ring connected through an enolated carbon forming by[4+2]cycloaddition.Their structures were elucidated by spectroscopic analysis and X-ray diffraction.1 exhibited moderate cytotoxicity against human colon cancer HT29 cells,and it induced significant cell cycle arrest by reducing the protein expression of cyclin D1.
基金This research was supported by the National Natural Science Foundation of China(No.81903488)the CAMS Innovation Fund for Medical Sciences(No.CIFMS-2021-I2M-1-026)。
文摘Five novel(9,10-dihydro)phenanthrene and bibenzyl trimers,as well as two previously identified biphenanthrenes and bibenzyls,were isolated from the tubers of Bletilla striata.Their structures were elucidated through comprehensive analyses of NMR and HRESIMS spectroscopic data.The absolute configurations of these compounds were determined by calculating rotational energy barriers and comparison of experimental and calculated ECD curves.Compounds 5b and 6 exhibited inhibitory effects on LPS-induced NO production in BV-2 cells,with IC_(50) values of 12.59±0.40 and 15.59±0.83μmol·L^(-1),respectively.A mechanistic study suggested that these compounds may attenuate neuroinflammation by reducing the activation of the AKT/IκB/NF-κB signaling pathway.Additionally,compounds 3a,6,and 7 demonstrated significant PTP1B inhibitory activities,with IC_(50) values of 1.52±0.34,1.39±0.11,and 1.78±0.01μmol·L^(-1),respectively.Further investigation revealed that compound 3a might inhibit LPS-induced PTP1B overexpression and NF-κB activation,thereby mitigating the neuroinflammatory response in BV-2 cells.
文摘One new A - type proanthocyanidin trimer, lindetannin trimer, was isolated from the stems of Lindera aggregata (Sims) Kosterm.. Its structure was elucidated by spectral and chemical methods.
基金support from the National Natural Sciences Foundation of China(NNSFCGrant Nos.81730093,81630094,and 81502942)+1 种基金CAMS Innovation Fund for Medical Science of China(2017-I2M-3-010 and 2016-I2M-1-004)the Drug Innovation Major Project(2018ZX09711001-001,China)is acknowledged is acknowledged.
文摘From an aqueous extract of“tian ma”(the steamed and dried rhizomes of Gastrodia elata),ten new compounds gastrodiben-zins A−D(1−4)and gastrotribenzins A−F(5−10),along with known analogues(11−20),having structure features coupling between two and three p-hydroxybenzyl-derived units via carbon-and/or ether-bonds,were isolated and characterized by spectroscopic data analysis.Meanwhile,the new compounds 5a,6a,8a,22,and 23,as well as the known derivatives 13a,14a,15,17−21,24,25,and p-hydroxybenzyl aldehyde were isolated and identified from a refluxed aqueous solution of p-hydroxybenzyl alcohol.Methylation of 5a and 6a in methanol and ethylation of 6a,8a,13a,and 14a in ethanol produced 5 and 6 and 7,8,13,and 14,respectively.using ultra-performance liquid chromatography high-resolution electrospray ioniza-tion mass spectrometry(UPLC-HRESIMS)analysis of the refluxed solutions of p-hydroxybenzyl alcohol and the refluxed extracts of the fresh G.elata rhizome and“tian ma”extracts indicated consistent production and variation of the dimeric and trimeric derivatives of p-hydroxybenzyl alcohol upon extracting solvents and refluxing time.In various assays,the dimeric and trimeric derivatives showed more potent activities than p-hydroxybenzyl alcohol itself and gastrodin,which are the main known active constituents of“tian ma”.These results revealed for the first time that the more effective dimers and trimers can be produced through condensation of the co-occurring p-hydroxybenzyl alcohol during processing and decocting of the G.elata rhizomes,demonstrating insights into medicinal chemistry behind application protocols of traditional Chinese medicines.
基金supported by the National Science Foundation of Fujian Province(No.2017J01039)
文摘A trimeric porous coordination framework [Ni_3(TPTC)(IN)_2(μ_2-H_2O)_2(CH_3OH)_2)]n· x(solvents)(1, TPTC = terphenyl-3,3?,5,5??-tetracarboxylic acid, IN = isonicotinic acid) was synthesized and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, single-crystal and powder X-ray diffraction. It crystallizes in monoclinic space group C2/c with a = 33739(12), b = 14.820(5), c = 13.568(5) ?, β = 97.388(6)o, V = 6728(4) ?3, Z = 4, Mr = 965.35, Dc = 0.953 g·cm^(-3), F(000) = 1955.5, μ = 0.881 mm^(–1), GOOF = 1.072, the final R = 0.0859 and w R = 0.2424 for 5284 observed reflections with I > 2σ(I). The structure of 1 is constructed from the linkage of trinuclear {Ni_3} second building units through TPTC and IN spacers, forming a 4,8-connected network of Schl?fli symbol {32.42.52}{34.46.58.68.72}. The CO2 uptake values for 1 are 97.9 m^2·g^(-1) at 273 K and 66.2 m^2·g^(-1) at 298 K, while its N_2 adsorption values are 8.5 m^2·g^(-1) at 273 K and 4.9 m^2·g^(-1) at 298 K, respectively. These results show that 1 has high CO_2/N_2 adsorption selectivity at ambient conditions.
