As a payload support system deployed on satellites,the turntable system is often switched among different working modes during the on-orbit operation,which can experience great state changes.In each mode,the missions ...As a payload support system deployed on satellites,the turntable system is often switched among different working modes during the on-orbit operation,which can experience great state changes.In each mode,the missions to be completed are different,consecutive and non-over-lapping,from which the turntable system can be considered to be a phased-mission system(PMS).Reliability analysis for PMS has been widely studied.However,the system mode cycle characteristic has not been taken into account before.In this paper,reliability analysis method of the satellite turntable system is proposed considering its multiple operation modes and mode cycle characteristic.Firstly,the multi-valued decision diagrams(MDD)manipulation rules between two adjacent mission cycles are proposed.On this basis,MDD models for the turntable system in different states are established and the reliability is calculated using the continuous time Markov chains(CTMC)method.Finally,the comparative study is carried out to show the effectiveness of our proposed method.展开更多
The multistage face gears are the core component of the planetary gear train,which is symmetrically meshed by multiple single-stage face gear and multiple cylindrical gears.However,it is difficult to synchronize the c...The multistage face gears are the core component of the planetary gear train,which is symmetrically meshed by multiple single-stage face gear and multiple cylindrical gears.However,it is difficult to synchronize the contact between face gears and cylindrical gear due to the tooth number differences.Thus,the interference problems between two stages and big stress concentration are obvious.The crown surface configuration technology and structure design were introduced to optimize the meshing condition.To improve the double crown design feasibility and meshing stability,it is necessary to establish a reasonable multistage face gears pair simulation model to evaluate various influence factors on the contact condition and quasi-static characteristics of multistage face gears structure.The relevant scatter plots are fitted by comparing the contact results with different crown quantities and friction coefficients to intuitively obtain the variation regularity of maximum deformation,maximum strain,maximum stress and maximum strain energy.The natural frequency and mode coefficient are also determined by modal analysis under these two conditions.All the above mentioned studies verified the contact conjugate properties of double crown surface configuration were suitable.The results can provide a foundation for structure optimization and transmission reliability of multistage face gears.展开更多
Bone injury and implantation operation are often accompanied by microenvironment damage of bone tis-sue,which seriously affects the process of osseointegration of implants,especially for titanium(Ti)-based bioinert ma...Bone injury and implantation operation are often accompanied by microenvironment damage of bone tis-sue,which seriously affects the process of osseointegration of implants,especially for titanium(Ti)-based bioinert materials.Thus,repairing or improving the microenvironment of damaged bone tissue is of great significance for bone rescue,reconstruction,and regeneration,which is still a major medical challenge.Oxidative stress(OS)and oxygen(O_(2))deficiency are considered to be specific physiological signals of the bone-injury microenvironment.From the above background,a coating consisting of manganese dioxide(MnO_(2))nanoenzyme and strontium(Sr)ions was fabricated on the surface of the Ti implant via a one-step hydrothermal treatment.MnO_(2) nanoenzyme presented in the coating alleviated OS and O_(2) deficiency at the injury site by catalyzing the decomposition of abundant endogenous H_(2)O_(2) around the modified Ti implants into O_(2).In addition,Sr ions were released from the surface of the implant at a certain rate in a body-fluid environment,further promoting the adhesion,growth,and osteogenic differentiation of mesenchymal stem cells.More importantly,a Sprague Dawley rat femur model demonstrated that the modified Ti implant showed significant potential to accelerate bone tissue reconstruction in vivo.In sum-mary,the present system provides a new idea for the treatment of bone injury and the development of new orthopedic implants.展开更多
Objective GGC repeat expansions in the human-specific NOTCH2NLC gene have been reported as the cause of neuronal intranuclear inclusion disease(NIID).Given the clinical overlap of cognitive impairment in NIID and cere...Objective GGC repeat expansions in the human-specific NOTCH2NLC gene have been reported as the cause of neuronal intranuclear inclusion disease(NIID).Given the clinical overlap of cognitive impairment in NIID and cerebral small vessel disease(CSVD),both diseases have white matter hyperintensity on T2-fluid attenuated inversion recovery sequences of brain MRI,and white matter hyperintensity is a primary neuroimaging marker of CSVD on MRI.Therefore,we hypothesised that the GGC repeat expansions might also contribute to CSVD.To further investigate the relationship between NOTCH2NLC GGC repeat expansions and CSVD,we performed a genetic analysis of 814 patients with the disease.Methods We performed a comprehensive GGC repeat expansion screening in NOTCH2NLC from 814 patients with sporadic CSVD.Their Fazekas score was greater than or equal to 3 points.Repeat-primed PCR and fluorescence amplicon length analyses were performed to identify GGC repeat expansions,and whole-exome sequencing was used to detect any pathogenic mutation in previously reported genes associated with CSVD.Results We identified nine(1.11%)patients with pathogenic GGC repeat expansions ranging from 41 to 98 repeats.The minor allele frequency of expanded GGC repeats in NOTCH2NLC was 0.55%.Conclusion Our findings suggest that intermediate-length and longer-length GGC repeat expansions in NOTCH2NLC are associated with sporadic CSVD.This provides new thinking for studying the pathogenesis of CSVD.展开更多
Fluorescence correlation spectroscopy (FCS) is capable of probing dynamic processes in living biological systems. From photon fluctuation of fluorescing particles which diffuse through a small detection volume, FCS re...Fluorescence correlation spectroscopy (FCS) is capable of probing dynamic processes in living biological systems. From photon fluctuation of fluorescing particles which diffuse through a small detection volume, FCS reveals information on the concentration and the structure of the particles, as well as information on microscopic environment. In this note, we study the radiation forces experienced by Rayleigh particles in a laser field in details, and analyze the effects of gradient field on FCS measurements.展开更多
The diagnosis of osteoporosis is eventually converted to the measurement of bone mineral density(BMD)in clinical trials.Since our previous work had proved the ability of using photoacoustic spectral analysis(PASA)to e...The diagnosis of osteoporosis is eventually converted to the measurement of bone mineral density(BMD)in clinical trials.Since our previous work had proved the ability of using photoacoustic spectral analysis(PASA)to efficiently detect osteoporosis,in this contribution,we proposed a fully connected multi-layer deep neural network combined with PASA to semi-quantify BMD values corresponding to varying degrees of bone loss and to further evaluate the degree of osteoporosis.Experiments were carried out on swine femur heads,and the performance of our proposed method is satisfying for future clinical screening.展开更多
Status epilepticus(SE) is a life-threatening neurological emergency associated with a high mortality rate. The serotonin 1A(5-HT1A) receptor is a possible target for the treatment of SE, but its role in animal models ...Status epilepticus(SE) is a life-threatening neurological emergency associated with a high mortality rate. The serotonin 1A(5-HT1A) receptor is a possible target for the treatment of SE, but its role in animal models and the precise area of brain involved remain controversial. The hippocampus is a candidate site due to its key role in the development of SE and the existence of a high density of 5-HT1A receptors. Therefore, we investigated the effects of subcutaneous and intrahippocampal activation of 5-HT1A receptors in lithium-pilocarpine-induced SE, and tested whether the hippocampus is a true effector site. We developed SE in male Sprague-Dawley rats by giving lithium chloride(LiCl; 3 meq/kg, i.p.) 22–24 h prior to pilocarpine(25 mg/kg, i.p.), and found that 8-OH-DPAT, a 5-HT1A receptor agonist administered subcutaneously(s.c.) at 0.5 or 1.0 mg/kg 1 h before pilocarpine injection increased the latency to the first epileptiform spikes, the electrographic SE, and the behavioral generalized seizures(GS), while reducing the total EEG seizure time(P <0.01). The duration of GS was shortened only by 1.0 mg/kg 8-OH-DPAT s.c.(P <0.05). All these effects were inhibited by combined administration of WAY-100635(1.0 mg/kg, s.c.)(P <0.05), an antagonist of the 5-HT1A receptor, but WAY-100635 alone and low doses of 8-OHDPAT(0.01 and 0.1 mg/kg) did not alter seizure activity. Furthermore, intrahippocampal 8-OH-DPAT only shortened the GS duration(P <0.05). These findings imply that the 5-HT1A receptor is a promisingtherapeutic target against the generation and propagation of SE, and hippocampal receptors are involved in reducing the seizure severity.展开更多
A double acid corrosion and subsequent hydrothermal treatment were used to fabricate a micro–nano-structured Ti substrates(Ti–M–N).Afterward,the mesoporous polydopamine(MPDA)nanoparticles as photothermal agent were...A double acid corrosion and subsequent hydrothermal treatment were used to fabricate a micro–nano-structured Ti substrates(Ti–M–N).Afterward,the mesoporous polydopamine(MPDA)nanoparticles as photothermal agent were prepared and immobilized on the surface of Ti–M–N samples,in order to obtain Ti–M–NMPDA sample.Unique micro–nanostructure properties and the photothermal effect of the modified Ti implant caused physical stress on the bacteria and the bacterial membrane damage,and eventually led to bacteria death.More importantly,based on excellent bioactivity and cytocompatibility of mussel-inspired materials,MPDA promoted adhesion,proliferation and osteogenic differentiation of mesenchymal stem cells in vitro.Furthermore,animal experiments in vivo further confirmed that the modified Ti implants could enhance osseointegration.展开更多
Insufficient osseointegration and biofilm-associated bacterial infection are important challenges for clinical application of titanium(Ti)-based implants.Here,we constructed mesoporous polydopamine(MPDA)nanoparticles(...Insufficient osseointegration and biofilm-associated bacterial infection are important challenges for clinical application of titanium(Ti)-based implants.Here,we constructed mesoporous polydopamine(MPDA)nanoparticles(NPs)loaded with luteolin(LUT,a quorum sensing inhibitor),which were further coated with the shell of calcium phosphate(CaP)to construct MPDA-LUT@CaP nanosystem.Then,MPDA-LUT@CaP NPs were immobilized on the surface of Ti implants.Under acidic environment of bacterial biofilm-infection,the CaP shell of MPDA-LUT@CaP NPs was rapidly degraded and released LUT,Ca^(2+)and PO_(4)^(3-)from the surface of Ti implant.LUT could effectively inhibit and disperse biofilm.Furthermore,under near-infrared irradiation(NIR),the thermotherapy induced by the photothermal conversion effect of MPDA destroyed the integrity of the bacterial membrane,and synergistically led to protein leakage and a decrease in ATP levels.Combined with photothermal therapy(PTT)and quorum-sensing-inhibition strategy,the surface-functionalized Ti substrate had an antibacterial rate of over 95.59%against Staphylococcus aureus and the elimination rate of the formed biofilm was as high as 90.3%,so as to achieve low temperature and efficient treatment of bacterial biofilm infection.More importantly,the modified Ti implant accelerated the growth of cell and the healing process of bone tissue due to the released Ca^(2+)and PO_(4)^(3-).In summary,this work combined PTT with quorum-sensing-inhibition strategy provides a new idea for surface functionalization of implant for achieving effective antibacterial and osseointegration capabilities.展开更多
Light bullets(LBs)are localized nonlinear waves propagating in high spatial dimensions.Finding stable LBs and realizing their control are desirable due to the interesting physics and potential applications.Here,we sho...Light bullets(LBs)are localized nonlinear waves propagating in high spatial dimensions.Finding stable LBs and realizing their control are desirable due to the interesting physics and potential applications.Here,we show that nonlocal LBs generated in a cold Rydberg atomic gas via the balance among the dispersion,diffraction,and giant nonlocal Kerr nonlinearity contributed by long-range Rydberg-Rydberg interaction can be actively manipulated by using a weak gradient magnetic field.Nonlocal LBs are generated by a balance among dispersion,diffraction,and large nonlocal Kerr nonlinearities contributed by long-range Rydberg-Rydberg interactions.Here,we find that active manipulation can be achieved by weak gradient magnetic fields in cold Rydberg atomic gases.Especially,the LBs may undergo significant Stern-Gerlach deflections,and their motion trajectories can be controlled by adjusting the magnetic-field gradient.The results reported here are helpful not only for understanding unique properties of LBs in nonlocal optical media but also for finding ways for precision measurements of magnetic fields.展开更多
基金co-supported by the Natural Science Foundation of China(No.61833016)the Shaanxi Out-standing Youth Science Foundation(No.2020JC-34)+1 种基金the Shaanxi Science and Technology Innovation Team(No.2022TD-24)the Natural Science Foundation of Heilongjiang Province of China(No.LH2021F038).
文摘As a payload support system deployed on satellites,the turntable system is often switched among different working modes during the on-orbit operation,which can experience great state changes.In each mode,the missions to be completed are different,consecutive and non-over-lapping,from which the turntable system can be considered to be a phased-mission system(PMS).Reliability analysis for PMS has been widely studied.However,the system mode cycle characteristic has not been taken into account before.In this paper,reliability analysis method of the satellite turntable system is proposed considering its multiple operation modes and mode cycle characteristic.Firstly,the multi-valued decision diagrams(MDD)manipulation rules between two adjacent mission cycles are proposed.On this basis,MDD models for the turntable system in different states are established and the reliability is calculated using the continuous time Markov chains(CTMC)method.Finally,the comparative study is carried out to show the effectiveness of our proposed method.
基金supported by the National Key Basic Research Program of China(973 Program,2014CB239303)the National Natural Science Foundation of China(21872031,U1705251)the Award Program for Minjiang Scholar Professorship~~
基金This work was supported by the National Natural Science Foundation of China(grant number 51575191).
文摘The multistage face gears are the core component of the planetary gear train,which is symmetrically meshed by multiple single-stage face gear and multiple cylindrical gears.However,it is difficult to synchronize the contact between face gears and cylindrical gear due to the tooth number differences.Thus,the interference problems between two stages and big stress concentration are obvious.The crown surface configuration technology and structure design were introduced to optimize the meshing condition.To improve the double crown design feasibility and meshing stability,it is necessary to establish a reasonable multistage face gears pair simulation model to evaluate various influence factors on the contact condition and quasi-static characteristics of multistage face gears structure.The relevant scatter plots are fitted by comparing the contact results with different crown quantities and friction coefficients to intuitively obtain the variation regularity of maximum deformation,maximum strain,maximum stress and maximum strain energy.The natural frequency and mode coefficient are also determined by modal analysis under these two conditions.All the above mentioned studies verified the contact conjugate properties of double crown surface configuration were suitable.The results can provide a foundation for structure optimization and transmission reliability of multistage face gears.
基金financially supported by the National Natu-ral Science Foundation of China (Nos.32171327,21734002,and 51825302)the Natural Science Foundation of Chongqing (No.cstc2021jcyj-cxttX0002).
文摘Bone injury and implantation operation are often accompanied by microenvironment damage of bone tis-sue,which seriously affects the process of osseointegration of implants,especially for titanium(Ti)-based bioinert materials.Thus,repairing or improving the microenvironment of damaged bone tissue is of great significance for bone rescue,reconstruction,and regeneration,which is still a major medical challenge.Oxidative stress(OS)and oxygen(O_(2))deficiency are considered to be specific physiological signals of the bone-injury microenvironment.From the above background,a coating consisting of manganese dioxide(MnO_(2))nanoenzyme and strontium(Sr)ions was fabricated on the surface of the Ti implant via a one-step hydrothermal treatment.MnO_(2) nanoenzyme presented in the coating alleviated OS and O_(2) deficiency at the injury site by catalyzing the decomposition of abundant endogenous H_(2)O_(2) around the modified Ti implants into O_(2).In addition,Sr ions were released from the surface of the implant at a certain rate in a body-fluid environment,further promoting the adhesion,growth,and osteogenic differentiation of mesenchymal stem cells.More importantly,a Sprague Dawley rat femur model demonstrated that the modified Ti implant showed significant potential to accelerate bone tissue reconstruction in vivo.In sum-mary,the present system provides a new idea for the treatment of bone injury and the development of new orthopedic implants.
基金supported by the Non-profit Central Research Institute Fund of Chinese Academy of Medical Sciences[grant number 2020-PT310-01]the National Natural Science Foundation of China to Dr.Chang-he Shi[grant number 82171247,81974211]the National Natural Science Foundation of China to Dr.Yu-ming Xu[grant numbers U1904207].
文摘Objective GGC repeat expansions in the human-specific NOTCH2NLC gene have been reported as the cause of neuronal intranuclear inclusion disease(NIID).Given the clinical overlap of cognitive impairment in NIID and cerebral small vessel disease(CSVD),both diseases have white matter hyperintensity on T2-fluid attenuated inversion recovery sequences of brain MRI,and white matter hyperintensity is a primary neuroimaging marker of CSVD on MRI.Therefore,we hypothesised that the GGC repeat expansions might also contribute to CSVD.To further investigate the relationship between NOTCH2NLC GGC repeat expansions and CSVD,we performed a genetic analysis of 814 patients with the disease.Methods We performed a comprehensive GGC repeat expansion screening in NOTCH2NLC from 814 patients with sporadic CSVD.Their Fazekas score was greater than or equal to 3 points.Repeat-primed PCR and fluorescence amplicon length analyses were performed to identify GGC repeat expansions,and whole-exome sequencing was used to detect any pathogenic mutation in previously reported genes associated with CSVD.Results We identified nine(1.11%)patients with pathogenic GGC repeat expansions ranging from 41 to 98 repeats.The minor allele frequency of expanded GGC repeats in NOTCH2NLC was 0.55%.Conclusion Our findings suggest that intermediate-length and longer-length GGC repeat expansions in NOTCH2NLC are associated with sporadic CSVD.This provides new thinking for studying the pathogenesis of CSVD.
文摘Fluorescence correlation spectroscopy (FCS) is capable of probing dynamic processes in living biological systems. From photon fluctuation of fluorescing particles which diffuse through a small detection volume, FCS reveals information on the concentration and the structure of the particles, as well as information on microscopic environment. In this note, we study the radiation forces experienced by Rayleigh particles in a laser field in details, and analyze the effects of gradient field on FCS measurements.
基金supported by the National Key Research and Development Program of China(No.2017YFC0111402)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.19KJB510031)the Natural Science Foundation of Jiangsu Province(No.BK20181256)。
文摘The diagnosis of osteoporosis is eventually converted to the measurement of bone mineral density(BMD)in clinical trials.Since our previous work had proved the ability of using photoacoustic spectral analysis(PASA)to efficiently detect osteoporosis,in this contribution,we proposed a fully connected multi-layer deep neural network combined with PASA to semi-quantify BMD values corresponding to varying degrees of bone loss and to further evaluate the degree of osteoporosis.Experiments were carried out on swine femur heads,and the performance of our proposed method is satisfying for future clinical screening.
基金supported by grants from the National Natural Science Foundation of China (81000556, 81100968, 81171227)the Traditional Chinese Medicine Scientific Research Fund of Zhejiang Province, China (2010ZA069)
文摘Status epilepticus(SE) is a life-threatening neurological emergency associated with a high mortality rate. The serotonin 1A(5-HT1A) receptor is a possible target for the treatment of SE, but its role in animal models and the precise area of brain involved remain controversial. The hippocampus is a candidate site due to its key role in the development of SE and the existence of a high density of 5-HT1A receptors. Therefore, we investigated the effects of subcutaneous and intrahippocampal activation of 5-HT1A receptors in lithium-pilocarpine-induced SE, and tested whether the hippocampus is a true effector site. We developed SE in male Sprague-Dawley rats by giving lithium chloride(LiCl; 3 meq/kg, i.p.) 22–24 h prior to pilocarpine(25 mg/kg, i.p.), and found that 8-OH-DPAT, a 5-HT1A receptor agonist administered subcutaneously(s.c.) at 0.5 or 1.0 mg/kg 1 h before pilocarpine injection increased the latency to the first epileptiform spikes, the electrographic SE, and the behavioral generalized seizures(GS), while reducing the total EEG seizure time(P <0.01). The duration of GS was shortened only by 1.0 mg/kg 8-OH-DPAT s.c.(P <0.05). All these effects were inhibited by combined administration of WAY-100635(1.0 mg/kg, s.c.)(P <0.05), an antagonist of the 5-HT1A receptor, but WAY-100635 alone and low doses of 8-OHDPAT(0.01 and 0.1 mg/kg) did not alter seizure activity. Furthermore, intrahippocampal 8-OH-DPAT only shortened the GS duration(P <0.05). These findings imply that the 5-HT1A receptor is a promisingtherapeutic target against the generation and propagation of SE, and hippocampal receptors are involved in reducing the seizure severity.
基金This work was financially supported by the State Key Project of Research and Development(Nos.2016YFC1100300 and 2017YFB0702603)the National Natural Science Foundation of China(Nos.51825302,21734002 and 51673032).The Analytical and Testing Center of Chongqing University is greatly acknowledged for the help with the characterization of materials.
文摘A double acid corrosion and subsequent hydrothermal treatment were used to fabricate a micro–nano-structured Ti substrates(Ti–M–N).Afterward,the mesoporous polydopamine(MPDA)nanoparticles as photothermal agent were prepared and immobilized on the surface of Ti–M–N samples,in order to obtain Ti–M–NMPDA sample.Unique micro–nanostructure properties and the photothermal effect of the modified Ti implant caused physical stress on the bacteria and the bacterial membrane damage,and eventually led to bacteria death.More importantly,based on excellent bioactivity and cytocompatibility of mussel-inspired materials,MPDA promoted adhesion,proliferation and osteogenic differentiation of mesenchymal stem cells in vitro.Furthermore,animal experiments in vivo further confirmed that the modified Ti implants could enhance osseointegration.
基金National Natural Science Foundation of China(32171327,21734002 and 51825302)the Natural Science Foundation of Chongqing(cstc2021jcyj-cxttX0002).
文摘Insufficient osseointegration and biofilm-associated bacterial infection are important challenges for clinical application of titanium(Ti)-based implants.Here,we constructed mesoporous polydopamine(MPDA)nanoparticles(NPs)loaded with luteolin(LUT,a quorum sensing inhibitor),which were further coated with the shell of calcium phosphate(CaP)to construct MPDA-LUT@CaP nanosystem.Then,MPDA-LUT@CaP NPs were immobilized on the surface of Ti implants.Under acidic environment of bacterial biofilm-infection,the CaP shell of MPDA-LUT@CaP NPs was rapidly degraded and released LUT,Ca^(2+)and PO_(4)^(3-)from the surface of Ti implant.LUT could effectively inhibit and disperse biofilm.Furthermore,under near-infrared irradiation(NIR),the thermotherapy induced by the photothermal conversion effect of MPDA destroyed the integrity of the bacterial membrane,and synergistically led to protein leakage and a decrease in ATP levels.Combined with photothermal therapy(PTT)and quorum-sensing-inhibition strategy,the surface-functionalized Ti substrate had an antibacterial rate of over 95.59%against Staphylococcus aureus and the elimination rate of the formed biofilm was as high as 90.3%,so as to achieve low temperature and efficient treatment of bacterial biofilm infection.More importantly,the modified Ti implant accelerated the growth of cell and the healing process of bone tissue due to the released Ca^(2+)and PO_(4)^(3-).In summary,this work combined PTT with quorum-sensing-inhibition strategy provides a new idea for surface functionalization of implant for achieving effective antibacterial and osseointegration capabilities.
基金This work was supported by the National Natural Science Foundation of China(NSFC)(Nos.11975098,11174080,and 11904104)the Shanghai Pujiang Program(No.21PJ1402500).
文摘Light bullets(LBs)are localized nonlinear waves propagating in high spatial dimensions.Finding stable LBs and realizing their control are desirable due to the interesting physics and potential applications.Here,we show that nonlocal LBs generated in a cold Rydberg atomic gas via the balance among the dispersion,diffraction,and giant nonlocal Kerr nonlinearity contributed by long-range Rydberg-Rydberg interaction can be actively manipulated by using a weak gradient magnetic field.Nonlocal LBs are generated by a balance among dispersion,diffraction,and large nonlocal Kerr nonlinearities contributed by long-range Rydberg-Rydberg interactions.Here,we find that active manipulation can be achieved by weak gradient magnetic fields in cold Rydberg atomic gases.Especially,the LBs may undergo significant Stern-Gerlach deflections,and their motion trajectories can be controlled by adjusting the magnetic-field gradient.The results reported here are helpful not only for understanding unique properties of LBs in nonlocal optical media but also for finding ways for precision measurements of magnetic fields.
