Rotational computed laminography(CL)has broad application potential in three-dimensional imaging of plate-like objects because it only requires X-rays to pass through the tested object in the thickness direction durin...Rotational computed laminography(CL)has broad application potential in three-dimensional imaging of plate-like objects because it only requires X-rays to pass through the tested object in the thickness direction during the imaging process.In this study,a rectangular cross-section field-of-view rotational CL(RC-CL)is proposed for circuit board imaging.Compared to other rotational CL systems,the field of view is the largest and most suitable for rectangular circuit boards.Meanwhile,as the imaging geometry of RC-CL is significantly different from that of cone-beam CT,the Feldkamp-Davis-Kress(FDK)reconstruction algorithm cannot be used directly.However,transferring the projection data to fit into the CBCT geometry using two-dimensional interpolation introduces interpolation errors.Therefore,an FDK-type analytical reconstruction algorithm applicable to RC-CL was developed.The effectiveness of the method was validated through numerical experiments,and the influence of the tilt angle on the reconstruction results was analyzed.Finally,the RC-CL technique was applied to real defect detection research on circuit boards.展开更多
Objective Chemoresistance represents a major obstacle in breast cancer(BC)treatment.Chelidonine could prevent various tumor cell types.However,the effect and mechanism of chelidonine against BC chemotherapy resistance...Objective Chemoresistance represents a major obstacle in breast cancer(BC)treatment.Chelidonine could prevent various tumor cell types.However,the effect and mechanism of chelidonine against BC chemotherapy resistance have not been elucidated.This paper aimed to explore the effect and mechanism of chelidonine on BC chemoresistance.Methods A CCK-8 assay,flow cytometry and fluorescence microscopy were applied to evaluate the resistance reversal effect of chelidonine on MCF-7/ADR cells.The signaling pathways by which chelidonine suppresses BC were predicted by network pharmacology and validated by Western blotting.The chemoresistant reversal mechanism of chelidonine was clarified using platelet-derived growth factor receptor-β(PDGFRβ)silencing with small interfering RNA(siRNA),platelet-derived growth factor-BB(PDGF-BB)stimulation,Western blotting and real-time quantitative polymerase chain reaction(RT-qPCR).Results Chelidonine remarkably reversed adriamycin(ADR)resistance by decreasing P-glycoprotein(P-gp)expression and the efflux of ADR in MCF-7/ADR cells.Additionally,PDGFRβexpression in MCF-7/ADR cells was markedly higher than that in MCF-7 cells(P<0.01),and PDGFRβknockdown prevented P-gp expression and intracellular ADR accumulation.Network pharmacology identified phosphatidylinositol 3-kinase/protein kinase B(PI3K/Akt)as a primary pathway of chelidonine-inhibiting BC,which was verified by the marked underexpression of phosphorylated kappa B inhibitor protein kinase(p-IKK),phosphorylated inhibitor of nuclear factor-κB(p-IKB),and nuclear factor-κB(NF-κB)and phosphatase and tensin homolog(PTEN)hyperexpression by chelidonine treatment(P<0.01).Notably,PDGFRβsilencing enhanced the inhibitory effect of chelidonine on the activation of the PI3K/Akt pathway.Moreover,chelidonine suppressed PDGF-BB stimulation of the PDGFRβ/PI3K/Akt axis.Conclusion These findings underscore the potential role of PDGFRβin regulating chemotherapy resistance in BC.Chelidonine could effectively overcome the resistance of MCF-7/ADR cells to ADR by targeting the PDGFRβ/PI3K/Akt axis.Meanwhile,these findings highlight the potential of chelidonine as a promising natural chemoresistant agent for BC treatment.展开更多
The mammalian brain has an extremely limited ability to regenerate lost neurons and to recover function following ischemic stroke.A biomaterial strategy of slowly-releasing various regeneration-promoting factors to ac...The mammalian brain has an extremely limited ability to regenerate lost neurons and to recover function following ischemic stroke.A biomaterial strategy of slowly-releasing various regeneration-promoting factors to activate endogenous neurogenesis represents a safe and practical neuronal replacement therapy.In this study,basic fibroblast growth factor(bFGF)-Chitosan gel is injected into the stroke cavity.This approach promotes the proliferation of vascular endothelial cell,the formation of functional vascular network,and the final restoration of cerebral blood flow.Additionally,bFGF-Chitosan gel activates neural progenitor cells(NPCs)in the subventricular zone(SVZ),promotes the NPCs’migration toward the stroke cavity and differentiation into mature neurons with diverse cell types(inhibitory gamma-aminobutyric acid neurons and excitatory glutamatergic neuron)and layer architecture(superficial cortex and deep cortex).These new-born neurons form functional synaptic connections with the host brain and reconstruct nascent neural networks.Furthermore,synaptogenesis in the stroke cavity and Nestin lineage cells respectively contribute to the improvement of sensorimotor function induced by bFGF-Chitosan gel after ischemic stroke.Lastly,bFGF-Chitosan gel inhibits microglia activation in the peri-infarct cortex.Our findings indicate that filling the stroke cavity with bFGF-Chitosan“brain glue”promotes angiogenesis,endogenous neurogenesis and synaptogenesis to restore function,offering innovative ideas and methods for the clinical treatment of ischemic stroke.展开更多
A fiber-optic Raman spectrum sensor system is used for the fast diagnosis of esophageal cancer during clinical endoscopic examination.The system contains a 785nm exciting laser,a Raman fiber-optic probe with 7 large c...A fiber-optic Raman spectrum sensor system is used for the fast diagnosis of esophageal cancer during clinical endoscopic examination.The system contains a 785nm exciting laser,a Raman fiber-optic probe with 7 large core fibers and a focus lens,and a highly sensitive spectrum meter.The Raman spectrum of the tissue could be obtained within 1 second by using such a system. A signal baseline removal and denoising technology is used to improve the signal quality.A novel signal feature extraction method for differentiating the normal and esophageal cancer tissues is proposed,based on the differences in half-height width(HHW)in 1200cm^-1 to 1400cm^-1 frequency band and the ratios of the spectral integral energy between 1600cm^-1-1700cm^-1 and 1500cm^-1- 1600cm^-1 band.It shows a high specificity and effectivity for the diagnosis of esophageal cancer.展开更多
Calcified coccolithophores, a diverse and widely distributed group of marine microalgae, produce biogenic calcite in the form ofcoccoliths located on the cell surface. Using batch incubations of the coccolithophorid P...Calcified coccolithophores, a diverse and widely distributed group of marine microalgae, produce biogenic calcite in the form ofcoccoliths located on the cell surface. Using batch incubations of the coccolithophorid Pleurochrysis carterae, we investigated the responses of this calcification process to iron concentrations by changing the iron supply in the initial culture media from a normal concentration to 1 ppm （parts per million）, 5 ppm, and 10 ppm. Time-dependent measurements of cell population, production of inorganic carbon （coccoliths）, and organic carbon （organic cellular components） showed that elevated iron supply in the growth medium of P. carterae stimulates carbon sequestration by increasing growth along enhanced photosynthetic activity and calcification. In addition, the acquired time-dependent UV-Vis and FT-IR spectra revealed that iron fertilization- enhanced coccolith calcification is accompanied by a crystalline phase transition from calcite to aragonite or amorphous phase. Our results suggest that iron concentration has a significant influence on the marine carbon cycle of coccolithophores.展开更多
When milling part surfaces with a ball-end tool in 5-axis CNC machining,maintaining a constant cutting speed by keeping a fixed inclination angle between the tool axis and surface normal is crucial to ensure safe oper...When milling part surfaces with a ball-end tool in 5-axis CNC machining,maintaining a constant cutting speed by keeping a fixed inclination angle between the tool axis and surface normal is crucial to ensure safe operation and achieve high quality of the machined surface.Under this constraint,the variation of tool orientation is expected to be“smoothest possible”to reduce the angular speed of the rotary axes for the efficient and robust machining.To address this issue,the spatial tractrix which is the extension of classic tractrix is presented to establish the geometry model of the tool orientation kinematics in the part coordinate system.The proposed model describes the relations between the tilt angle and the variation of ball-end tool orientation.Two spatial tractrix-based methods,synchronizing tractrix-based method and equilibrating tractrix-based method,are developed to minimize the variation of tool orientation by controlling the variation of tilt angle.These methods are used to plan the tool orientation on a part surface modeled by a bicubic spline surface.The performance evaluation carried by intense simulations demonstrates the equilibrating tractrix-based method provide the best results in most cases compared with the existing differential geometry-based methods such as the tractrix-based method and parallel transport method.The synchronizing tractrix-based method works well in some special cases.展开更多
Dear Editor,Ion gradients are characteristic features of a living cell that do not represent thermodynamic equilibrium.These unequilibrium status are maintained by various ion pumps such as Na-K-ATPase,which are known...Dear Editor,Ion gradients are characteristic features of a living cell that do not represent thermodynamic equilibrium.These unequilibrium status are maintained by various ion pumps such as Na-K-ATPase,which are known as the P-type ATPases.Working mechanism of Na-K-ATPase is described as Post-Albers cycle1(Fig.1a).However,the reaction scheme is non-Michaelis-Menten kinetics assembled from transient-state results,which can hardly be used to rebuild the real reaction cycle.展开更多
基金supported by the National Key Research and Development Program of China(No.2022YFF0607802)。
文摘Rotational computed laminography(CL)has broad application potential in three-dimensional imaging of plate-like objects because it only requires X-rays to pass through the tested object in the thickness direction during the imaging process.In this study,a rectangular cross-section field-of-view rotational CL(RC-CL)is proposed for circuit board imaging.Compared to other rotational CL systems,the field of view is the largest and most suitable for rectangular circuit boards.Meanwhile,as the imaging geometry of RC-CL is significantly different from that of cone-beam CT,the Feldkamp-Davis-Kress(FDK)reconstruction algorithm cannot be used directly.However,transferring the projection data to fit into the CBCT geometry using two-dimensional interpolation introduces interpolation errors.Therefore,an FDK-type analytical reconstruction algorithm applicable to RC-CL was developed.The effectiveness of the method was validated through numerical experiments,and the influence of the tilt angle on the reconstruction results was analyzed.Finally,the RC-CL technique was applied to real defect detection research on circuit boards.
基金supported by Heilongjiang Natural Science Foundation Joint Guidance Project(No.LH2022H001).
文摘Objective Chemoresistance represents a major obstacle in breast cancer(BC)treatment.Chelidonine could prevent various tumor cell types.However,the effect and mechanism of chelidonine against BC chemotherapy resistance have not been elucidated.This paper aimed to explore the effect and mechanism of chelidonine on BC chemoresistance.Methods A CCK-8 assay,flow cytometry and fluorescence microscopy were applied to evaluate the resistance reversal effect of chelidonine on MCF-7/ADR cells.The signaling pathways by which chelidonine suppresses BC were predicted by network pharmacology and validated by Western blotting.The chemoresistant reversal mechanism of chelidonine was clarified using platelet-derived growth factor receptor-β(PDGFRβ)silencing with small interfering RNA(siRNA),platelet-derived growth factor-BB(PDGF-BB)stimulation,Western blotting and real-time quantitative polymerase chain reaction(RT-qPCR).Results Chelidonine remarkably reversed adriamycin(ADR)resistance by decreasing P-glycoprotein(P-gp)expression and the efflux of ADR in MCF-7/ADR cells.Additionally,PDGFRβexpression in MCF-7/ADR cells was markedly higher than that in MCF-7 cells(P<0.01),and PDGFRβknockdown prevented P-gp expression and intracellular ADR accumulation.Network pharmacology identified phosphatidylinositol 3-kinase/protein kinase B(PI3K/Akt)as a primary pathway of chelidonine-inhibiting BC,which was verified by the marked underexpression of phosphorylated kappa B inhibitor protein kinase(p-IKK),phosphorylated inhibitor of nuclear factor-κB(p-IKB),and nuclear factor-κB(NF-κB)and phosphatase and tensin homolog(PTEN)hyperexpression by chelidonine treatment(P<0.01).Notably,PDGFRβsilencing enhanced the inhibitory effect of chelidonine on the activation of the PI3K/Akt pathway.Moreover,chelidonine suppressed PDGF-BB stimulation of the PDGFRβ/PI3K/Akt axis.Conclusion These findings underscore the potential role of PDGFRβin regulating chemotherapy resistance in BC.Chelidonine could effectively overcome the resistance of MCF-7/ADR cells to ADR by targeting the PDGFRβ/PI3K/Akt axis.Meanwhile,these findings highlight the potential of chelidonine as a promising natural chemoresistant agent for BC treatment.
基金supported by the National Natural Science Foundation of China,Nos.31730030(to XL),82272171(to ZY),82271403(to XL),81941011(to XL),31971279(to ZY),31771053(to HD),82472244(to XZ),82272116(to LC)the Natural Science Foundation of Beijing,No.7222004(to HD)Science and Technology Innovation Plan of Shanghai Science and Technology Commission,No.23Y31900300(to YM).the CAMS Initiative for Innovative Medicine,2021-1-I2M-019(to XB),National High Level Hospital Clinical Research Funding,2022-PUMCH-C-042(to XB).
文摘The mammalian brain has an extremely limited ability to regenerate lost neurons and to recover function following ischemic stroke.A biomaterial strategy of slowly-releasing various regeneration-promoting factors to activate endogenous neurogenesis represents a safe and practical neuronal replacement therapy.In this study,basic fibroblast growth factor(bFGF)-Chitosan gel is injected into the stroke cavity.This approach promotes the proliferation of vascular endothelial cell,the formation of functional vascular network,and the final restoration of cerebral blood flow.Additionally,bFGF-Chitosan gel activates neural progenitor cells(NPCs)in the subventricular zone(SVZ),promotes the NPCs’migration toward the stroke cavity and differentiation into mature neurons with diverse cell types(inhibitory gamma-aminobutyric acid neurons and excitatory glutamatergic neuron)and layer architecture(superficial cortex and deep cortex).These new-born neurons form functional synaptic connections with the host brain and reconstruct nascent neural networks.Furthermore,synaptogenesis in the stroke cavity and Nestin lineage cells respectively contribute to the improvement of sensorimotor function induced by bFGF-Chitosan gel after ischemic stroke.Lastly,bFGF-Chitosan gel inhibits microglia activation in the peri-infarct cortex.Our findings indicate that filling the stroke cavity with bFGF-Chitosan“brain glue”promotes angiogenesis,endogenous neurogenesis and synaptogenesis to restore function,offering innovative ideas and methods for the clinical treatment of ischemic stroke.
基金multicenter clinical study of endoscopic diagnosis of early esophageal cancer(Grant No.SWH2016ZDCX3007)the State 111 Project(Grant No.B14039)+3 种基金Application of endoscopic minimally invasive technique in diagnosis and treatment of digestive tract injury and disease(Grant No.SWH2016ZDCX2011)Study of effect on fibroblast transdifferentiation and prevention of postoperative esophagus stenosis through regulating the TRADD(Grant No. 81470907)the National Natural Science Foundation of China(NSFC)(Grant Nos.51627806and 51875091)Application of Raman imaging in the diagnosis of gastric cancer(Grant No. cstc2015shmszx 10017).
文摘A fiber-optic Raman spectrum sensor system is used for the fast diagnosis of esophageal cancer during clinical endoscopic examination.The system contains a 785nm exciting laser,a Raman fiber-optic probe with 7 large core fibers and a focus lens,and a highly sensitive spectrum meter.The Raman spectrum of the tissue could be obtained within 1 second by using such a system. A signal baseline removal and denoising technology is used to improve the signal quality.A novel signal feature extraction method for differentiating the normal and esophageal cancer tissues is proposed,based on the differences in half-height width(HHW)in 1200cm^-1 to 1400cm^-1 frequency band and the ratios of the spectral integral energy between 1600cm^-1-1700cm^-1 and 1500cm^-1- 1600cm^-1 band.It shows a high specificity and effectivity for the diagnosis of esophageal cancer.
文摘Calcified coccolithophores, a diverse and widely distributed group of marine microalgae, produce biogenic calcite in the form ofcoccoliths located on the cell surface. Using batch incubations of the coccolithophorid Pleurochrysis carterae, we investigated the responses of this calcification process to iron concentrations by changing the iron supply in the initial culture media from a normal concentration to 1 ppm （parts per million）, 5 ppm, and 10 ppm. Time-dependent measurements of cell population, production of inorganic carbon （coccoliths）, and organic carbon （organic cellular components） showed that elevated iron supply in the growth medium of P. carterae stimulates carbon sequestration by increasing growth along enhanced photosynthetic activity and calcification. In addition, the acquired time-dependent UV-Vis and FT-IR spectra revealed that iron fertilization- enhanced coccolith calcification is accompanied by a crystalline phase transition from calcite to aragonite or amorphous phase. Our results suggest that iron concentration has a significant influence on the marine carbon cycle of coccolithophores.
基金supported by National Natural Science Foundation of China(No.51975231)。
文摘When milling part surfaces with a ball-end tool in 5-axis CNC machining,maintaining a constant cutting speed by keeping a fixed inclination angle between the tool axis and surface normal is crucial to ensure safe operation and achieve high quality of the machined surface.Under this constraint,the variation of tool orientation is expected to be“smoothest possible”to reduce the angular speed of the rotary axes for the efficient and robust machining.To address this issue,the spatial tractrix which is the extension of classic tractrix is presented to establish the geometry model of the tool orientation kinematics in the part coordinate system.The proposed model describes the relations between the tilt angle and the variation of ball-end tool orientation.Two spatial tractrix-based methods,synchronizing tractrix-based method and equilibrating tractrix-based method,are developed to minimize the variation of tool orientation by controlling the variation of tilt angle.These methods are used to plan the tool orientation on a part surface modeled by a bicubic spline surface.The performance evaluation carried by intense simulations demonstrates the equilibrating tractrix-based method provide the best results in most cases compared with the existing differential geometry-based methods such as the tractrix-based method and parallel transport method.The synchronizing tractrix-based method works well in some special cases.
基金supported by National Natural Science Foundation of China (81970418,82272116)Shanghai Municipal Science and Technology Major Project (No.2018SHZDZX01)+3 种基金ZJLabScience and Technology Commission of Shanghai Municipality (Grant No.18JC1410403)MOE Frontiers Center for Brain ScienceShanghai Municipal Health Commission Key Research Centre (2022ZZ01006).
文摘Dear Editor,Ion gradients are characteristic features of a living cell that do not represent thermodynamic equilibrium.These unequilibrium status are maintained by various ion pumps such as Na-K-ATPase,which are known as the P-type ATPases.Working mechanism of Na-K-ATPase is described as Post-Albers cycle1(Fig.1a).However,the reaction scheme is non-Michaelis-Menten kinetics assembled from transient-state results,which can hardly be used to rebuild the real reaction cycle.
