Accurate mechanical modeling is essential for robotic belt grinding(RBG), a process characterized by compliant contact mechanisms that make force prediction particularly challenging. However, existing mechanical model...Accurate mechanical modeling is essential for robotic belt grinding(RBG), a process characterized by compliant contact mechanisms that make force prediction particularly challenging. However, existing mechanical models predominantly focus on macroscale compliance while neglecting grain-scale compliant motion. Moreover, abrasive grains are typically idealized as regular shapes, overlooking the inherent stochasticity of real grain geometries. This study proposes a shapeequivalence method for modeling stochastic abrasive grains and develops a multiscale compliant force model for RBG. Specifically, an individual grain is represented as a polygonal pyramid with stochastic edges that is mathematically equivalent to a cone;this method unifies the treatment of grain geometries and streamlines the modeling process. The mathematical equivalence relationship for random grain shapes is further derived based on a grain-compliant contact model. By integrating grain geometric characteristics and progressive grain wear, an analytical mechanical model that captures both the static contact force and dynamic grinding force is established, thereby describing the transition from grain-workpiece compliant interaction to belt-workpiece elastic contact. Grinding experiments were conducted using abrasive belts with different grain shape distributions to validate the model. The results demonstrated reliable predictions of the tangential grinding force and its component characteristics. Additional analyses were performed to reveal how the tangential grinding force varies with wear time and grinding parameters.展开更多
The capability of whole-body proprioception,e.g.,pose estimation,is important for the control and interaction of continuum robots.However,existing pose estimation methods are often simplified through geometric assumpt...The capability of whole-body proprioception,e.g.,pose estimation,is important for the control and interaction of continuum robots.However,existing pose estimation methods are often simplified through geometric assumptions,primarily due to constraints such as computational and sensor deployment costs.We propose an explicit posture estimation method through a neural network,and implement it using an embedded camera for vision-based proprioception.We design a continuous location encoding neural network(LENN)by encoding continuous locational information.The LENN can capture deformation from changes in internal texture observed by an integrated camera,and output pose information—both position and orientation—for any point along the robot backbone,rather than only discrete points.Compared with interpolation-based estimation using a reduced model,our method reduces single-point estimation error by 33.6%.Furthermore,a systematic evaluation of hardware configurations demonstrates that our prototype achieves sub-millimetre accuracy in shape estimation(0.383 mm)while maintaining real-time inference speeds below 12 ms per frame.By combining a learning-based approach with a simple mechanical design,our method leverages internal visual information to estimate the whole-body pose,providing an effective solution for accurate shape estimation in continuum robots.展开更多
Robotic belt grinding has emerged as a finishing process in recent years for machining components with high surface finish and flexibility.The surface machining consistency,however,is difficult to be guaranteed in suc...Robotic belt grinding has emerged as a finishing process in recent years for machining components with high surface finish and flexibility.The surface machining consistency,however,is difficult to be guaranteed in such a process.To overcome this problem,a method of hybrid force-position control combined with PI/PD control is proposed to be applied in robotic abrasive belt grinding of complex geometries.Voltage signals are firstly obtained and transformed to force information with signal conditioning methods.Secondly,zero drift and gravity compensation algorithms are presented to calibrate the F/T transducer which is installed on the robot end-effector.Next,a force control strategy combining hybrid force-position control with PI/PD control is introduced to be employed in robotic abrasive belt grinding operations where the force control law is applied to the Z direction of the tool frame and the positon control law is used in the X direction of the tool frame.Then,the accuracy of the F/T transducer and the robotic force control system is analyzed to ensure the stability and reliability of force control in the robotic grinding process.Finally,two typical cases on robotic belt grinding of a test workpiece and an aero-engine blade are conducted to validate the practicality and effectiveness of the force control technology proposed.展开更多
Dear Editor,Active magnetic bearings(AMBs)are of considerable interest and significance in smart manufacturing due to their zero-friction and adaptivity to noncontact rotor rotations.This paper proposes an active levi...Dear Editor,Active magnetic bearings(AMBs)are of considerable interest and significance in smart manufacturing due to their zero-friction and adaptivity to noncontact rotor rotations.This paper proposes an active levitation control algorithm based on adaptive sliding mode control(ASMC)equipped with linear extended state observer(LESO).Sufficient conditions are derived to guarantee the asymptotical stability of the associated closed-loop system.Experiments are conducted on a real AMB-rotor platform to demonstrate the effectiveness and superiority of the proposed algorithm.展开更多
BACKGROUND Ras-related protein Rab24,which belongs to the small GTPase family,plays a crucial role in regulating intracellular protein trafficking.Dysregulation of Rab24 has been recently identified in hepatocellular ...BACKGROUND Ras-related protein Rab24,which belongs to the small GTPase family,plays a crucial role in regulating intracellular protein trafficking.Dysregulation of Rab24 has been recently identified in hepatocellular carcinoma(HCC).However,its clinical significance and tumor related effects remain to be further clarified.AIM To explore the expression pattern of Rab24 and its role in HCC progression.METHODS The expression profile of Rab24 was tested in HCC tissues together with adjacent tissues from transcriptional,mRNA,and protein levels.The prognostic role of Rab24 in HCC was assessed by univariate and multivariate analyses.Clinical outcomes were evaluated by the Kaplan-Meier analysis and log-rank test.The effect of Rab24 on cell proliferation was tested through cellular experiments and xenograft experiments.RESULTS Rab24 expression was elevated in HCC tissues compared to adjacent liver tissues.High expression of Rab24 was significantly associated with larger tumor size and advanced tumor stage.Moreover,HCC patients with high Rab24 expression showed poorer overall survival,and Rab24 was identified as an independent prognosis factor according to multivariate analysis.By using overexpression and shRNA knockdown strategies in HCC cell lines,we found that Rab24 can promote HCC proliferation.Finally,we validated that silencing Rab24 significantly attenuated xenograft growth in vivo.CONCLUSION Our study demonstrated that high expression of Rab24 was significantly correlated with poorer prognosis of HCC patients,indicating the potential of Rab24 as a novel clinical biomarker and therapeutic target.展开更多
Bone marrow-derived mesenchymal stem cells differentiate into neurons under the induction of Schwann cells. However, key microRNAs and related pathways for differentiation remain unclear. This study screened and ident...Bone marrow-derived mesenchymal stem cells differentiate into neurons under the induction of Schwann cells. However, key microRNAs and related pathways for differentiation remain unclear. This study screened and identified differentially expressed microRNAs in bone marrow- derived mesenchymal stem cells induced by Schwann cell-conditioned medium, and explored targets and related pathways involved in their differentiation into neuronal-like cells. Primary bone marrow-derived mesenchymal stem cells were isolated from femoral and tibial bones, while primary Schwann cells were isolated from bilateral saphenous nerves. Bone marrow-derived mesenchymal stem cells were cultured in unconditioned (control group) and Schwann cell-conditioned medium (bone marrow-derived mesenchymal stem cell + Schwann cell group). Neuronal differentiation of bone marrow-derived mesenchymal stem cells induced by Schwann cell-conditioned medium was observed by time-lapse imaging. Upon induction, the morphology of bone marrow-derived mesencaymal stem cells changed into a neural shape with neurites. Results of quantitative reverse transcription-polymerase chain reaction revealed that nestin mRNA expression was upregulated from 1 to 3 days and downregulated from 3 to 7 days in the bone marrow-derived mesenchymal stem cell + Schwann cell group. Compared with the control group, microtubule-associated protein 2 mRNA expression gradually increased from 1 to 7 days in the bone marrow-derived mesenchymal stem cell + Schwann cell group. After 7 days of induction, microRNA analysis iden:ified 83 significantly differentially expressed microRNAs between the two groups. Gene Ontology analysis indicated enrichment of microRNA target genes for neuronal projection development, regulation of axonogenesis, and positive regulation of cell proliferation. Kyoto Encyclopedia of Genes and Genomes pathway analysis demonstrated that Hippo, Wnt, transforming growth factor-beta, and Hedgehog signaling pathv/ays were potentially associated with neural differentiation of bone marrow-derived mesenchymal stem cells. This study, which carried out successful microRNA analysis of neuronal-like cells differentiated from bone marrow-derived mesenchymal stem cells by Schwann cell induction, revealed key microRNAs and pathways involved in neural differentiation of bone marrow-derived mesenchymal stem cells. All protocols were approved by the Animal Ethics Committee of Institute of Radiation Medicine, Chinese Academy of Medical Sciences on March 12, 2017 (approval number: DWLI-20170311).展开更多
This study investigated the effects of superheated steam(SS)treatment at different temperatures(120℃,150℃,180℃)on the physicochemical properties of broken rice flour and the quality of broken rice cakes.SS treatmen...This study investigated the effects of superheated steam(SS)treatment at different temperatures(120℃,150℃,180℃)on the physicochemical properties of broken rice flour and the quality of broken rice cakes.SS treatment at 120℃ significantly enhanced the moisture content of broken rice flour(P<0.05).In contrast,treatments at 150℃ and 180℃ caused decrease of moisture content,amylose leaching,and reduction of damaged starch content.After SS treatment,the pasting properties of broken rice flour increased,along with the rising of storage modulus and loss modulus.The proportion of short chains(DP 6-12)in amylopectin increased from 29.42%to 34.80%(P<0.05),which could delay starch retrogradation.Compared with untreated ones,the SS-150 broken rice cakes showed a significantly higher specific volume(2.96 mL/g,P<0.05),more uniform cell structure,and lower hardness(1.66 N)and chewiness(10.22 mJ).After 7 days of storage,cakes from SS-treated rice flour(150℃ and 180℃)had significantly reduced hardness and chewiness.The study demonstrated that SS treatment could improve the properties of broken rice flour and enhance the quality of broken rice cakes,especially at 150℃ and 180℃.This study presents a method for improving the quality of broken rice flour and rice cakes using superheated steam treatment,addressing challenges related to poor flour characteristics and suboptimal cake quality.The findings offer technical and theoretical support for enhancing rice cake production,contributing to the comprehensive utilization of rice resources.展开更多
Aconitum(Ranunculaceae)has a long-standing history in traditional Chinese medicine(TCM),where it has been widely used to treat conditions such as rheumatoid arthritis(RA),myocardial infarction,and heart failure.Howeve...Aconitum(Ranunculaceae)has a long-standing history in traditional Chinese medicine(TCM),where it has been widely used to treat conditions such as rheumatoid arthritis(RA),myocardial infarction,and heart failure.However,the potency of Aconitum alkaloids,the primary active components of Aconitum,also confers substantial toxicity.Therefore,assessing the efficacy and toxicity of these Aconitum alkaloids is crucial for ensuring clinical effectiveness and safety.Metabolomics,a quantitative method for analyzing low-molecular-weight metabolites involved in metabolic pathways,provides a comprehensive view of the metabolic state across multiple systems in vivo.This approach has become a vital investigative tool for facilitating the evaluation of their efficacy and toxicity,identifying potential sensitive biomarkers,and offering a promising avenue for elucidating the pharmacological and toxicological mechanisms underlying TCM.This review focuses on the applications of metabolomics in pharmacological and toxicological studies of Aconitum alkaloids in recent years and highlights the significant role of metabolomics in exploring compatibility detoxification and the mechanisms of TCM processing,aiming to identify more viable methods for characterizing toxic medicinal plants.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.52505554,52575571)the Postdoctoral Fellowship Program of CPSF (Grant No.GZB20250348)。
文摘Accurate mechanical modeling is essential for robotic belt grinding(RBG), a process characterized by compliant contact mechanisms that make force prediction particularly challenging. However, existing mechanical models predominantly focus on macroscale compliance while neglecting grain-scale compliant motion. Moreover, abrasive grains are typically idealized as regular shapes, overlooking the inherent stochasticity of real grain geometries. This study proposes a shapeequivalence method for modeling stochastic abrasive grains and develops a multiscale compliant force model for RBG. Specifically, an individual grain is represented as a polygonal pyramid with stochastic edges that is mathematically equivalent to a cone;this method unifies the treatment of grain geometries and streamlines the modeling process. The mathematical equivalence relationship for random grain shapes is further derived based on a grain-compliant contact model. By integrating grain geometric characteristics and progressive grain wear, an analytical mechanical model that captures both the static contact force and dynamic grinding force is established, thereby describing the transition from grain-workpiece compliant interaction to belt-workpiece elastic contact. Grinding experiments were conducted using abrasive belts with different grain shape distributions to validate the model. The results demonstrated reliable predictions of the tangential grinding force and its component characteristics. Additional analyses were performed to reveal how the tangential grinding force varies with wear time and grinding parameters.
基金supported by the National Natural Science Foundation of China(Grant Nos.52188102,52505008)the National Key Research and Development Program of China(Grant No.2024YFB4707902)。
文摘The capability of whole-body proprioception,e.g.,pose estimation,is important for the control and interaction of continuum robots.However,existing pose estimation methods are often simplified through geometric assumptions,primarily due to constraints such as computational and sensor deployment costs.We propose an explicit posture estimation method through a neural network,and implement it using an embedded camera for vision-based proprioception.We design a continuous location encoding neural network(LENN)by encoding continuous locational information.The LENN can capture deformation from changes in internal texture observed by an integrated camera,and output pose information—both position and orientation—for any point along the robot backbone,rather than only discrete points.Compared with interpolation-based estimation using a reduced model,our method reduces single-point estimation error by 33.6%.Furthermore,a systematic evaluation of hardware configurations demonstrates that our prototype achieves sub-millimetre accuracy in shape estimation(0.383 mm)while maintaining real-time inference speeds below 12 ms per frame.By combining a learning-based approach with a simple mechanical design,our method leverages internal visual information to estimate the whole-body pose,providing an effective solution for accurate shape estimation in continuum robots.
基金National Nature Science Foundation of China(Nos.51675394and 51375196)National Key Research and Development Program of China(No.2017YFB1303404)+2 种基金State Key Laboratory of Digital Manufacturing Equipment and Technology of China(No.DMETKF2018018)Fundamental Research Funds for the Central Universities of China(No.2017II33GX)the Key R&D Program of Jiangsu Province(No.BE2015005)
文摘Robotic belt grinding has emerged as a finishing process in recent years for machining components with high surface finish and flexibility.The surface machining consistency,however,is difficult to be guaranteed in such a process.To overcome this problem,a method of hybrid force-position control combined with PI/PD control is proposed to be applied in robotic abrasive belt grinding of complex geometries.Voltage signals are firstly obtained and transformed to force information with signal conditioning methods.Secondly,zero drift and gravity compensation algorithms are presented to calibrate the F/T transducer which is installed on the robot end-effector.Next,a force control strategy combining hybrid force-position control with PI/PD control is introduced to be employed in robotic abrasive belt grinding operations where the force control law is applied to the Z direction of the tool frame and the positon control law is used in the X direction of the tool frame.Then,the accuracy of the F/T transducer and the robotic force control system is analyzed to ensure the stability and reliability of force control in the robotic grinding process.Finally,two typical cases on robotic belt grinding of a test workpiece and an aero-engine blade are conducted to validate the practicality and effectiveness of the force control technology proposed.
基金supported in part by the National Natural Science Foundation of China(62225306,U2141235,52188102).
文摘Dear Editor,Active magnetic bearings(AMBs)are of considerable interest and significance in smart manufacturing due to their zero-friction and adaptivity to noncontact rotor rotations.This paper proposes an active levitation control algorithm based on adaptive sliding mode control(ASMC)equipped with linear extended state observer(LESO).Sufficient conditions are derived to guarantee the asymptotical stability of the associated closed-loop system.Experiments are conducted on a real AMB-rotor platform to demonstrate the effectiveness and superiority of the proposed algorithm.
文摘BACKGROUND Ras-related protein Rab24,which belongs to the small GTPase family,plays a crucial role in regulating intracellular protein trafficking.Dysregulation of Rab24 has been recently identified in hepatocellular carcinoma(HCC).However,its clinical significance and tumor related effects remain to be further clarified.AIM To explore the expression pattern of Rab24 and its role in HCC progression.METHODS The expression profile of Rab24 was tested in HCC tissues together with adjacent tissues from transcriptional,mRNA,and protein levels.The prognostic role of Rab24 in HCC was assessed by univariate and multivariate analyses.Clinical outcomes were evaluated by the Kaplan-Meier analysis and log-rank test.The effect of Rab24 on cell proliferation was tested through cellular experiments and xenograft experiments.RESULTS Rab24 expression was elevated in HCC tissues compared to adjacent liver tissues.High expression of Rab24 was significantly associated with larger tumor size and advanced tumor stage.Moreover,HCC patients with high Rab24 expression showed poorer overall survival,and Rab24 was identified as an independent prognosis factor according to multivariate analysis.By using overexpression and shRNA knockdown strategies in HCC cell lines,we found that Rab24 can promote HCC proliferation.Finally,we validated that silencing Rab24 significantly attenuated xenograft growth in vivo.CONCLUSION Our study demonstrated that high expression of Rab24 was significantly correlated with poorer prognosis of HCC patients,indicating the potential of Rab24 as a novel clinical biomarker and therapeutic target.
基金supported by the National Natural Science Foundation of China,No.81330042,81620108018(both to SQF),and 81702147(to ZJW)
文摘Bone marrow-derived mesenchymal stem cells differentiate into neurons under the induction of Schwann cells. However, key microRNAs and related pathways for differentiation remain unclear. This study screened and identified differentially expressed microRNAs in bone marrow- derived mesenchymal stem cells induced by Schwann cell-conditioned medium, and explored targets and related pathways involved in their differentiation into neuronal-like cells. Primary bone marrow-derived mesenchymal stem cells were isolated from femoral and tibial bones, while primary Schwann cells were isolated from bilateral saphenous nerves. Bone marrow-derived mesenchymal stem cells were cultured in unconditioned (control group) and Schwann cell-conditioned medium (bone marrow-derived mesenchymal stem cell + Schwann cell group). Neuronal differentiation of bone marrow-derived mesenchymal stem cells induced by Schwann cell-conditioned medium was observed by time-lapse imaging. Upon induction, the morphology of bone marrow-derived mesencaymal stem cells changed into a neural shape with neurites. Results of quantitative reverse transcription-polymerase chain reaction revealed that nestin mRNA expression was upregulated from 1 to 3 days and downregulated from 3 to 7 days in the bone marrow-derived mesenchymal stem cell + Schwann cell group. Compared with the control group, microtubule-associated protein 2 mRNA expression gradually increased from 1 to 7 days in the bone marrow-derived mesenchymal stem cell + Schwann cell group. After 7 days of induction, microRNA analysis iden:ified 83 significantly differentially expressed microRNAs between the two groups. Gene Ontology analysis indicated enrichment of microRNA target genes for neuronal projection development, regulation of axonogenesis, and positive regulation of cell proliferation. Kyoto Encyclopedia of Genes and Genomes pathway analysis demonstrated that Hippo, Wnt, transforming growth factor-beta, and Hedgehog signaling pathv/ays were potentially associated with neural differentiation of bone marrow-derived mesenchymal stem cells. This study, which carried out successful microRNA analysis of neuronal-like cells differentiated from bone marrow-derived mesenchymal stem cells by Schwann cell induction, revealed key microRNAs and pathways involved in neural differentiation of bone marrow-derived mesenchymal stem cells. All protocols were approved by the Animal Ethics Committee of Institute of Radiation Medicine, Chinese Academy of Medical Sciences on March 12, 2017 (approval number: DWLI-20170311).
基金supported by the Postdoctoral Innovation Project of Shandong Province (SDCX-ZG-202303090).
文摘This study investigated the effects of superheated steam(SS)treatment at different temperatures(120℃,150℃,180℃)on the physicochemical properties of broken rice flour and the quality of broken rice cakes.SS treatment at 120℃ significantly enhanced the moisture content of broken rice flour(P<0.05).In contrast,treatments at 150℃ and 180℃ caused decrease of moisture content,amylose leaching,and reduction of damaged starch content.After SS treatment,the pasting properties of broken rice flour increased,along with the rising of storage modulus and loss modulus.The proportion of short chains(DP 6-12)in amylopectin increased from 29.42%to 34.80%(P<0.05),which could delay starch retrogradation.Compared with untreated ones,the SS-150 broken rice cakes showed a significantly higher specific volume(2.96 mL/g,P<0.05),more uniform cell structure,and lower hardness(1.66 N)and chewiness(10.22 mJ).After 7 days of storage,cakes from SS-treated rice flour(150℃ and 180℃)had significantly reduced hardness and chewiness.The study demonstrated that SS treatment could improve the properties of broken rice flour and enhance the quality of broken rice cakes,especially at 150℃ and 180℃.This study presents a method for improving the quality of broken rice flour and rice cakes using superheated steam treatment,addressing challenges related to poor flour characteristics and suboptimal cake quality.The findings offer technical and theoretical support for enhancing rice cake production,contributing to the comprehensive utilization of rice resources.
基金supported by the National Natural Science Foundation of China (No.82274223)。
文摘Aconitum(Ranunculaceae)has a long-standing history in traditional Chinese medicine(TCM),where it has been widely used to treat conditions such as rheumatoid arthritis(RA),myocardial infarction,and heart failure.However,the potency of Aconitum alkaloids,the primary active components of Aconitum,also confers substantial toxicity.Therefore,assessing the efficacy and toxicity of these Aconitum alkaloids is crucial for ensuring clinical effectiveness and safety.Metabolomics,a quantitative method for analyzing low-molecular-weight metabolites involved in metabolic pathways,provides a comprehensive view of the metabolic state across multiple systems in vivo.This approach has become a vital investigative tool for facilitating the evaluation of their efficacy and toxicity,identifying potential sensitive biomarkers,and offering a promising avenue for elucidating the pharmacological and toxicological mechanisms underlying TCM.This review focuses on the applications of metabolomics in pharmacological and toxicological studies of Aconitum alkaloids in recent years and highlights the significant role of metabolomics in exploring compatibility detoxification and the mechanisms of TCM processing,aiming to identify more viable methods for characterizing toxic medicinal plants.
