Objective:To investigate the characteristics of'Jin Shang',a specialized term in traditional Chinese medicine(TCM)theory,in young adults with chronic neck pain(CNP)and investigated the correlation of'Jin S...Objective:To investigate the characteristics of'Jin Shang',a specialized term in traditional Chinese medicine(TCM)theory,in young adults with chronic neck pain(CNP)and investigated the correlation of'Jin Shang'with pain intensity and living disabilities using cross-section study.Methods:The thickness of the bilateral splenius capitis and semispinalis capitis were measured by ultrasound imaging(USI)as the objective performance of'Jin Shang'.The visual analogue scale(VAS)and Northwick Park Questionnaire(NPQ)were used to assess pain intensity and living disability.The Student's t test was used to investigate the difference in neck extensor muscle(NEM)thickness between CNP patients and healthy controls.Pearson's correlation and multiple linear regression were applied to investigate the relationship between NEM thickness,pain intensity and disability.Results:Fifty-nine young adult CNP patients and 16 healthy controls were recruited in this study,in accordance with specific inclusion and exclusion criteria.The student's t test showed that in CNP patients,the thickness of the semispinalis capitis during isometric contraction was significantly thinner than that of healthy controls(P=.04).Pearson's correlation analysis also revealed significant relationships between NEM thickness,VAS,and NPQ,while multiple linear regression showed that the thickness of the NEM in CNP patients was a significant predictor of pain intensity and disability.Conclusion:There was a significant difference in the thickness of the NEM in young adults with CNP when compared to healthy controls.Alterations in the NEM thickness in both rest and contraction are moderately related to neck pain and living disabilities.Our results investigated the characteristics of'Jin Shang'using USI and revealed a correlation between'Jin Shang'and CNP symptoms,which demonstrates that NEM plays an important role in CNP.展开更多
Exploring metal cluster reactivity with alkyl halides enables to understand the related chemical mechanism of metal surfaces in terms of active sites.Here we report a study of Ag_(n)^(+)(n=1-27)clusters reacting with ...Exploring metal cluster reactivity with alkyl halides enables to understand the related chemical mechanism of metal surfaces in terms of active sites.Here we report a study of Ag_(n)^(+)(n=1-27)clusters reacting with iodomethane by a flow tube apparatus in tandem with a customized triple quadrupole mass spectrometer.Strong even/odd alternation of the Ag_(n)^(+)is observed in their reactions with CH_(3)I,where silver clusters with even-number,Ag_(2n)^(+),find favorable products of Ag_(2n)I_(1,3)^(+)series,while the Ag_(2n−1)^(+)clusters form Ag_(2n−1)I_(2,4)^(+)products.Interestingly,Ag_(9)^(+)shows up with prominent mass abundance but allows for the formation of Ag_(9)I_(2)^(+),which finds an echo with the formation of Ag_(10)I_(3)^(+).We illustrate the enhanced stability of Ag_(9)I_(2)^(+)and Ag_(10)I_(3)^(+)by showing their significantly enlarged highest occupied molecular orbital(HOMO)-lowest unoccupied molecular orbital(LUMO)gaps and balanced charge distribution compared with the bare metal clusters,respectively.Also elucidated,is the superatomic nature of these bare and iodinated silver clusters,especially Ag_(9)I_(2)^(+)which mimics the rare-gas compound XeF_(2).This study expands a vivid example of special and general superatoms,and enriches the general knowledge on how a ligand stabilizes a metal cluster.展开更多
ZnTi-layered double hydroxides(LDHs) with varying Zn/Ti ratio have been synthesized by coprecipitation of zinc and titanium salts from homogeneous solution.The obtained ZnTi-LDHs possess high crystallinity and hiera...ZnTi-layered double hydroxides(LDHs) with varying Zn/Ti ratio have been synthesized by coprecipitation of zinc and titanium salts from homogeneous solution.The obtained ZnTi-LDHs possess high crystallinity and hierarchical structure with improved UV-absorbance property.The UV-vis spectra show that the UV absorbing properties of ZnTi-LDHs is stronger and broader than both MgAl-LDH and ZnAl-LDH due to the existence of Ti.Moreover,the UV absorption property increased with the content of Ti,which can be ascribed to the decrease in the band gap energy,as clearly confirmed by density functional theory calculations.When irradiated by UV rays,the property of the samples with generated free radicals(OH^·and O2^·) was evaluated by means of electron spin resonance(EPR).ZnTi-LDHs generated a relatively lower active radicals in contrast with TiO2 and ZnO,which implied an increased safety used as sunscreens.Therefore,this work provides a detailed understanding of UV shielding properties of ZnTiLDHs which was unrevealed previously,and demonstrates the expansive application prospects of ZnTiLDHs in the field of sunscreens.展开更多
We have prepared well-resolved Nb^(+)_(n)(n=1-10)clusters and report here an in-depth study on the es-sentially different reactivity with N_(2)and O_(2),by utilizing a multiple-ion laminar flow tube reactor in tandem ...We have prepared well-resolved Nb^(+)_(n)(n=1-10)clusters and report here an in-depth study on the es-sentially different reactivity with N_(2)and O_(2),by utilizing a multiple-ion laminar flow tube reactor in tandem with a customized triple quadrupole mass spectrometer(MIFT-TQMS).As results,the Nb^(+)_(n)clus-ters are found to readily react with N_(2)and form adsorption products Nb_(n)N^(+)_(2m);in contrast,the reactions with O_(2)give rise to Nb_(n)O^(+)_(1−4)products,and the odd-oxygen products indicate O-O bond dissociation,as well as increased mass abundance of NbO^(+)pertaining to oxygen-etching reactions.We illustrate how N_(2) prefers a physical adsorption on Nb^(+)_(n)clusters with an end-on orientation for all the products,and allow for size-selective Nb^(+)_(n)clusters to act as electron donor or acceptor in forming Nb_(n)N^(+)_(2m).In contrast to these nitrides,the dioxides Nb_(n)O+2display much larger binding energies,with O_(2)always as an electron acceptor,corresponding to superoxide or peroxide states in the initial reactions.Density-of-states and orbital anal-yses show that the interactions between Nb^(+)_(n)and O_(2)are dominated by strongπ-backdonation indicative of incidental electron transfer;whereas weakπ-backdonation and simultaneousσdonation interactions exist in Nb_(n)N^(+)_(2).Further,reaction dynamics analysis illustrates the different interactions for N_(2)and O_(2) in approaching the Nb^(+)_(n)clusters,showing the energy diagrams for N_(2)adsorption and O-O bond dissoci-ation in producing odd-oxygen products.Fragment analyses with orbital correlation and donor-acceptor charge transfer are also performed,giving rise to full insights into the reactivities and interactions of such transition metal clusters with typical diatomic molecules.展开更多
文摘Objective:To investigate the characteristics of'Jin Shang',a specialized term in traditional Chinese medicine(TCM)theory,in young adults with chronic neck pain(CNP)and investigated the correlation of'Jin Shang'with pain intensity and living disabilities using cross-section study.Methods:The thickness of the bilateral splenius capitis and semispinalis capitis were measured by ultrasound imaging(USI)as the objective performance of'Jin Shang'.The visual analogue scale(VAS)and Northwick Park Questionnaire(NPQ)were used to assess pain intensity and living disability.The Student's t test was used to investigate the difference in neck extensor muscle(NEM)thickness between CNP patients and healthy controls.Pearson's correlation and multiple linear regression were applied to investigate the relationship between NEM thickness,pain intensity and disability.Results:Fifty-nine young adult CNP patients and 16 healthy controls were recruited in this study,in accordance with specific inclusion and exclusion criteria.The student's t test showed that in CNP patients,the thickness of the semispinalis capitis during isometric contraction was significantly thinner than that of healthy controls(P=.04).Pearson's correlation analysis also revealed significant relationships between NEM thickness,VAS,and NPQ,while multiple linear regression showed that the thickness of the NEM in CNP patients was a significant predictor of pain intensity and disability.Conclusion:There was a significant difference in the thickness of the NEM in young adults with CNP when compared to healthy controls.Alterations in the NEM thickness in both rest and contraction are moderately related to neck pain and living disabilities.Our results investigated the characteristics of'Jin Shang'using USI and revealed a correlation between'Jin Shang'and CNP symptoms,which demonstrates that NEM plays an important role in CNP.
基金supported by the Ministry of Science and Technology of China(2020YFA0714602)the National Natural Science Foundation of China(21722308,22003072)CAS Instrument Development Project(Y5294512C1)。
文摘Exploring metal cluster reactivity with alkyl halides enables to understand the related chemical mechanism of metal surfaces in terms of active sites.Here we report a study of Ag_(n)^(+)(n=1-27)clusters reacting with iodomethane by a flow tube apparatus in tandem with a customized triple quadrupole mass spectrometer.Strong even/odd alternation of the Ag_(n)^(+)is observed in their reactions with CH_(3)I,where silver clusters with even-number,Ag_(2n)^(+),find favorable products of Ag_(2n)I_(1,3)^(+)series,while the Ag_(2n−1)^(+)clusters form Ag_(2n−1)I_(2,4)^(+)products.Interestingly,Ag_(9)^(+)shows up with prominent mass abundance but allows for the formation of Ag_(9)I_(2)^(+),which finds an echo with the formation of Ag_(10)I_(3)^(+).We illustrate the enhanced stability of Ag_(9)I_(2)^(+)and Ag_(10)I_(3)^(+)by showing their significantly enlarged highest occupied molecular orbital(HOMO)-lowest unoccupied molecular orbital(LUMO)gaps and balanced charge distribution compared with the bare metal clusters,respectively.Also elucidated,is the superatomic nature of these bare and iodinated silver clusters,especially Ag_(9)I_(2)^(+)which mimics the rare-gas compound XeF_(2).This study expands a vivid example of special and general superatoms,and enriches the general knowledge on how a ligand stabilizes a metal cluster.
基金supported by the National Natural Science Foundation of China (No. 21301012)the Development of High-Caliber Talents Project of Beijing Municipal Institutions (No. CIT & TCD 201504009)+1 种基金China Cosmetic Collaborative Innovation Center, BTBUthe Open Research Fund Program of Beijing Key Lab of Plant Resource Research and Development, BTBU
文摘ZnTi-layered double hydroxides(LDHs) with varying Zn/Ti ratio have been synthesized by coprecipitation of zinc and titanium salts from homogeneous solution.The obtained ZnTi-LDHs possess high crystallinity and hierarchical structure with improved UV-absorbance property.The UV-vis spectra show that the UV absorbing properties of ZnTi-LDHs is stronger and broader than both MgAl-LDH and ZnAl-LDH due to the existence of Ti.Moreover,the UV absorption property increased with the content of Ti,which can be ascribed to the decrease in the band gap energy,as clearly confirmed by density functional theory calculations.When irradiated by UV rays,the property of the samples with generated free radicals(OH^·and O2^·) was evaluated by means of electron spin resonance(EPR).ZnTi-LDHs generated a relatively lower active radicals in contrast with TiO2 and ZnO,which implied an increased safety used as sunscreens.Therefore,this work provides a detailed understanding of UV shielding properties of ZnTiLDHs which was unrevealed previously,and demonstrates the expansive application prospects of ZnTiLDHs in the field of sunscreens.
基金financially supported by the CAS Instrument Development Project (No.Y5294512C1)the National Natural Science Foundation of China (No.21722308)Key Research Program of Frontier Sciences (CAS No.QYZDBSSWSLH024)。
文摘We have prepared well-resolved Nb^(+)_(n)(n=1-10)clusters and report here an in-depth study on the es-sentially different reactivity with N_(2)and O_(2),by utilizing a multiple-ion laminar flow tube reactor in tandem with a customized triple quadrupole mass spectrometer(MIFT-TQMS).As results,the Nb^(+)_(n)clus-ters are found to readily react with N_(2)and form adsorption products Nb_(n)N^(+)_(2m);in contrast,the reactions with O_(2)give rise to Nb_(n)O^(+)_(1−4)products,and the odd-oxygen products indicate O-O bond dissociation,as well as increased mass abundance of NbO^(+)pertaining to oxygen-etching reactions.We illustrate how N_(2) prefers a physical adsorption on Nb^(+)_(n)clusters with an end-on orientation for all the products,and allow for size-selective Nb^(+)_(n)clusters to act as electron donor or acceptor in forming Nb_(n)N^(+)_(2m).In contrast to these nitrides,the dioxides Nb_(n)O+2display much larger binding energies,with O_(2)always as an electron acceptor,corresponding to superoxide or peroxide states in the initial reactions.Density-of-states and orbital anal-yses show that the interactions between Nb^(+)_(n)and O_(2)are dominated by strongπ-backdonation indicative of incidental electron transfer;whereas weakπ-backdonation and simultaneousσdonation interactions exist in Nb_(n)N^(+)_(2).Further,reaction dynamics analysis illustrates the different interactions for N_(2)and O_(2) in approaching the Nb^(+)_(n)clusters,showing the energy diagrams for N_(2)adsorption and O-O bond dissoci-ation in producing odd-oxygen products.Fragment analyses with orbital correlation and donor-acceptor charge transfer are also performed,giving rise to full insights into the reactivities and interactions of such transition metal clusters with typical diatomic molecules.