This paper gives an error analysis of radial motion measurement of ultra-precision spindle including nonlinearity error of capacitive displacement probes, misalignment error of probes, eccentric error of artifact ball...This paper gives an error analysis of radial motion measurement of ultra-precision spindle including nonlinearity error of capacitive displacement probes, misalignment error of probes, eccentric error of artifact ball and error induced by different error separating methods. Firstly, nonlinearity of a capacitive displacement probe targeting a spherical surface is investigated through experiment and the phenomena of fake displacement induced by lateral offset of the probe relative to an artifact ball?are?discussed. It is shown that the error motion in radial and axial direction and eccentric rotation of artifact ball will both induce lateral offset which causes a fake output of probes. Moreover, measurement error induced by angular positioning error for three famous error separating methods is detailed.展开更多
In the machining of high-end optical components,the aerostatic spindle error of an ultra-precision machine tool has a significant impact on the surface quality of the machined surfaces.The surfaces of many high-end op...In the machining of high-end optical components,the aerostatic spindle error of an ultra-precision machine tool has a significant impact on the surface quality of the machined surfaces.The surfaces of many high-end optical components need to meet the extremely stringent requirements of the full-frequency band error,which poses significant challenge to the control of the aerostatic spindle error.In this research,we put forward an active control method for the frequency domain error of the aerostatic spindle based on acoustic levitation,in which the acousticmagnetism-fluid-solid multi-field coupling rotor dynamics modeling method of the aerostatic spindle was proposed and the corresponding multi-field coupling model was established.Through the numerical simulation and preliminary experiments,the influence law of acoustic levitation on the frequency domain error of the aerostatic spindle is obtained.The results showed that acoustic levitation can be used to control the frequency domain error of the aerostatic spindle to some extent,which verified the effectiveness of the proposed method.展开更多
BACKGROUND Hepatitis B virus(HBV)infection is a leading cause of global hepatocellular carcinoma(HCC).Conventional biomarkers such as alpha-fetoprotein(AFP)demonstrate suboptimal sensitivity and specificity.Emerging e...BACKGROUND Hepatitis B virus(HBV)infection is a leading cause of global hepatocellular carcinoma(HCC).Conventional biomarkers such as alpha-fetoprotein(AFP)demonstrate suboptimal sensitivity and specificity.Emerging evidence suggests that serum extra spindle pole bodies like 1(ESPL1)protein and p53 antibody may improve diagnostic accuracy.AIM To assess and compare the diagnostic performance of serum ESPL1 protein and p53 antibody in HBV-related HCC(HBV-HCC).METHODS This case-control study from the First Affiliated Hospital of Guangxi Medical University enrolled 30 patients with chronic hepatitis B(CHB),30 with HBV-related liver cirrhosis(HBV-LC),55 with HBV-HCC,and 30 healthy controls.Serum ESPL1 protein and p53 antibody levels were quantified via ELISA.Diagnostic performance was evaluated using receiver operating characteristic(ROC)curve analysis,including sensitivity,specificity,and correlation with AFP.RESULTS Serum ESPL1 protein levels progressively increased across disease stages(CHB:89.9 ng/L;HBV-LC:188.83 ng/L;HBV-HCC:317.63 ng/L),with a significantly higher area under the ROC curve(AUC=0.917)than either p53 antibody(AUC=0.725)or AFP(AUC=0.678).p53 antibody levels were significantly elevated only in the HBVHCC group.ESPL1 demonstrated superior sensitivity and concordance with histopathological findings.A significant correlation between ESPL1 and p53 antibody levels was observed exclusively in the HBV-HCC group(r=0.320,P=0.017),suggesting potential interplay in malignant transformation.CONCLUSION Serum ESPL1 protein,a promising biomarker for early HBV-HCC detection,outperforms p53 antibody in diagnostic reliability.Higher ESPL1 levels correlate with increased HCC risk in chronic HBV patients.展开更多
In order to minimize vibration and improve rotary precision of spindle, we apply active vibration control technique to ultra-precision turning machine based on the analysis of vibration characteristic of aerostatic be...In order to minimize vibration and improve rotary precision of spindle, we apply active vibration control technique to ultra-precision turning machine based on the analysis of vibration characteristic of aerostatic bearing spindle. Using aerostatic bearing itself as actuator, the vibration of spindle is controlled by adjusting admission pressure respectively and by changing pressure distribution in the bearing. The experiments and simulations prove that this method can minimize the vibration of spindle effectively.展开更多
BACKGROUND Metastatic cardiac tumors are known to occur more frequently than primary cardiac tumors,however,they often remain asymptomatic and are commonly dis-covered on autopsy.Malignant tumors with a relatively hig...BACKGROUND Metastatic cardiac tumors are known to occur more frequently than primary cardiac tumors,however,they often remain asymptomatic and are commonly dis-covered on autopsy.Malignant tumors with a relatively high frequency of cardiac metastasis include mesothelioma,melanoma,lung cancer,and breast cancer,whereas reports of esophageal cancer with cardiac metastasis are rare.CASE SUMMARY The case of a 60-year-old man who complained of dysphagia is presented.Upper gastrointestinal endoscopy showed a submucosal tumor-like elevated lesion in the esophagus causing stenosis.Contrast-enhanced computed tomography showed left atrial compression due to the esophageal tumor,multiple liver and lung metastases,and a left pleural effusion.Pathological examination of a biopsy speci-men from the esophageal tumor showed spindle-shaped cells,raising suspicion of esophageal sarcoma.The disease progressed rapidly,and systemic chemotherapy was deemed necessary,however,due to his poor general condition,adminis-tration of cytotoxic agents was considered difficult.Given his high Combined Positive Score,nivolumab was administered,however,the patient soon died from the disease.The autopsy confirmed spindle cell carcinoma(SCC)of the esophagus and cardiac metastasis with similar histological features.Cancer stem cell markers,ZEB1 and TWIST,were positive in both the primary tumor and the cardiac metastasis.CONCLUSION To the best of our knowledge,there have been no prior reports of cardiac metastasis of esophageal SCC.This case highlights our experience with a patient with esophageal SCC who progressed rapidly and died from the disease,with the autopsy examination showing cardiac metastasis.展开更多
CtBP-interacting protein(CtIP)is known for its multifaceted roles in DNA repair and genomic stability,directing the homologous recombination-mediated DNA double-stranded break repair pathway via DNA end resection,an e...CtBP-interacting protein(CtIP)is known for its multifaceted roles in DNA repair and genomic stability,directing the homologous recombination-mediated DNA double-stranded break repair pathway via DNA end resection,an essential error-free repair process vital for genome stability.Mammalian oocytes are highly prone to DNA damage accumulation due to prolonged G2/prophase arrest.Here,we explore the functions of CtIP in meiotic cell cycle regulation via a mouse oocyte model.Depletion of CtIP by siRNA injection results in delayed germinal vesicle breakdown and failed polar body extrusion.Mechanistically,CtIP deficiency increases DNA damage and decreases the expression and nuclear entry of CCNB1,resulting in marked impairment of meiotic resumption,which can be rescued by exogenous CCNB1 overexpression.Furthermore,depletion of CtIP disrupts microtubule-organizing centers coalescence at spindle poles as indicated by failed accumulation ofγ-tubulin,p-Aurora kinase A,Kif2A,and TPX2,leading to abnormal spindle assembly and prometaphase arrest.These results provide valuable insights into the important roles of CtIP in the G2/M checkpoint and spindle assembly in mouse oocyte meiotic cell cycle regulation.展开更多
This study presents the development of an ultrasonic transducer with a radius horn for an ultrasonic milling spindle(UMS)system.The ultrasonic transducer was intended to have a working frequency of approximately 30 kH...This study presents the development of an ultrasonic transducer with a radius horn for an ultrasonic milling spindle(UMS)system.The ultrasonic transducer was intended to have a working frequency of approximately 30 kHz.Two different materials were considered in the study:stainless steel(SS 316L)and titanium alloy(Ti-6Al-4V).Titanium alloy gave a higher resonance frequency(33 kHz)than stainless steel(30 kHz)under the same preload compression stress.An electromechanical impedance simulation was carried out to predict the impedance resonance frequency for both materials,and the effect of the overhanging toolbar was investigated.According to the electromechanical impedance simulation,the overhanging toolbar length affected the resonance frequency,and the error was less than 3%.Harmonic analysis confirmed that the damping ratio helps determine the resonance amplitude.Therefore,damping ratios of 0.015-0.020 and 0.005-0.020 were selected for stainless steel and titanium alloy,respectively,with an error of less than 1.5%.Experimental machining was also performed to assess the feasibility of ultrasonic-assisted milling;the result was a lesser cutting force and better surface topography of Al 6061.展开更多
Significant advancements in ultra-precision machining technology have forced a re-examination of the spindle perpendicularity errors'impact on the milled surface quality at the micro-nano scale.In this paper,a met...Significant advancements in ultra-precision machining technology have forced a re-examination of the spindle perpendicularity errors'impact on the milled surface quality at the micro-nano scale.In this paper,a method of spindle precision adjustment is proposed to enhance surface finish quality.Sensitive errors in the machining process are identified using multi-body kinematic theory,with the milling process serving as an example.A two-degree-of-freedom(2-DOF)rotation platform is designed,optimized,and fabricated.The platform's static model is established based on elastic beam theory and verified by finite element analysis.Structural parameters are optimized via the response surface method in combination with the Pareto front.Experimental results reveal the effects of spindle speed,voltage amplitude,vibration frequency,cutting depth,and feed rate on the platform's modulation performance.The static modulation experiment shows that the perpendicularity error between the spindle and the guideway can be reduced from 92.5μrad to 0.25μrad.Finally,milling experiments show that the surface quality can be improved by 37.6%after spindle modulation.展开更多
With the growing demand for the fabrication of microminiaturized components,a comprehensive understanding of material removal behavior during ultra-precision cutting has become increasingly significant.Single-crystal ...With the growing demand for the fabrication of microminiaturized components,a comprehensive understanding of material removal behavior during ultra-precision cutting has become increasingly significant.Single-crystal sapphire stands out as a promising material for microelectronic components,ultra-precision lenses,and semiconductor structures owing to its exceptional characteristics,such as high hardness,chemical stability,and optical properties.This paper focuses on understanding the mechanism responsible for generating anisotropic crack morphologies along various cutting orientations on four crystal planes(C-,R-,A-,and M-planes)of sapphire during ultra-precision orthogonal cutting.By employing a scanning electric microscope to examine the machined surfaces,the crack morphologies can be categorized into three distinct types on the basis of their distinctive features:layered,sculptured,and lateral.To understand the mechanism determining crack morphology,visualized parameters related to the plastic deformation and cleavage fracture parameters are utilized.These parameters provide insight into both the likelihood and direction of plastic deformation and fracture system activations.Analysis of the results shows that the formation of crack morphology is predominantly influenced by the directionality of crystallographic fracture system activation and by the interplay between fracture and plastic deformation system activations.展开更多
Due to the non-linearity behavior of the precision positioning system, an accurate mathematical control model is difficult to set up, a novel control method for ultra-precision alignment is presented. This method reli...Due to the non-linearity behavior of the precision positioning system, an accurate mathematical control model is difficult to set up, a novel control method for ultra-precision alignment is presented. This method relies on neural network and alignment marks that are in the form of 100μm pitch gratings. The 0-th order Moire signals＇ intensity and its intensity rate are chosen as input variables of the neural network. The characteristics of the neural network make it possible to perform self-training and self-adjusting so as to achieve automatic precision alignment. A neural network model for precision positioning is set up. The model is composed of three neural layers, i.e. input layer, hidden layer and output layer. Driving signal is obtained by mapping Moire signals＇ intensity and its intensity rate. The experimental results show that neural network control for precision positioning can effectively improve positioning speed with high accuracy. It has the advantages of fast, stable response and good robustness. The device based on neural network can achieve the positioning accuracy of ± 0. 5μm.展开更多
A novel method for automatic ultra-precision alignment is presented.This method relies on the modified Moiré technique,and alignment marks are used in the form of gratings.The modified Moiré technique can ef...A novel method for automatic ultra-precision alignment is presented.This method relies on the modified Moiré technique,and alignment marks are used in the form of gratings.The modified Moiré technique can effectively improve detecting sensitivity of signals and simplify the control system by using only one pair of laser-Moiré sensors.We present the mathematical model and simulation results of diffracting two gratings.The effect of various parameters on Moiré signals is studied theoretically and experimentally,and the results are found to be consistent.A computer controlled alignment device using one pair of Moiré sensors is designed.The device can achieve a fully automatic precision alignment by the modified Moiré signal.The experimental result shows that the alignment device can obtain the resolution of 5 nm and the positioning accuracy of ±0 5 μm.展开更多
An applicable method to control regenerative cutting chatter automatically based on the optimal regulation of spindle speed is introduced. The optimal value of the phase shift angle of the regenerative chatter signal ...An applicable method to control regenerative cutting chatter automatically based on the optimal regulation of spindle speed is introduced. The optimal value of the phase shift angle of the regenerative chatter signal between the two successive cuts is 270°. The cutting process can be adjusted from the unstable region to stable one whenever regenerative chatter occurs if the phase shift angle is kept 270° by the optimal regulation of spindle speed. The theoretical analysis and the experimental results prove that the optimal regulation of spindle speed can effectively control regenerative cutting chatter. In addition, a reliablelly optimal control system of reliable spindle speed is presented. There is no need for system identification of the machine tool, and it is easy to put this regenerative chatter control method into practice, so the method has excellent application prospect.展开更多
In this paper we address the dynamics of compensation cutting process from both Laplace s frequency domain and the time domain of the first time, using the two computer aided analyzing softwares: MATLAB and SIMULI...In this paper we address the dynamics of compensation cutting process from both Laplace s frequency domain and the time domain of the first time, using the two computer aided analyzing softwares: MATLAB and SIMULINK. Theoretical analysis and simulation experiments firstly show that not only the systematical stiffness of workpiece, spindle and tools, but also the regenerated coefficient affects the compensation displacement effect. The results show that the SREC is practicable in reality to decease the spindle induced errors in many engineering applications such as hard boring through simulation and the preliminary experiment results.展开更多
To date, the medium and long-term space flight is urgent in need and has become a major task of our manned space flight program. There is no doubt that medium and long-term space flight has serious damaging impact upo...To date, the medium and long-term space flight is urgent in need and has become a major task of our manned space flight program. There is no doubt that medium and long-term space flight has serious damaging impact upon human physiological systems. For instance, atrophy of the lower limb anti-gravity muscle can be induced during the space flight. Muscle atrophy significantly affects the flight of astronauts in space. Most importantly, it influences the precise manipulation of the astronauts and their response capacity to emergencies on returning to the atmosphere from space. Muscle atrophy caused by weightlessness may also seriously disrupt the normal life and ＇work of the astronauts during the re-adaptation period. Here we summarize the corresponding research concentrating on weightlessness-induced changes of muscular structure and function. By combining research on muscle pain, which is a common clinical pain disease, we further provide a hypothesis concerning a dynamic feedback model of ＂weightlessness condition → muscular atrophy ←→ muscle pain＂. This may be useful to explore the neural mechanisms underlying the occurrence and development of muscular atrophy and muscle pain, through the key study of muscle spindle, and furthermore provide more effective therapy for clinical treatment.展开更多
The compliance modeling is one of the most significant issues in the stage of preliminary design for parallel kinematic machine（PKM）. The gravity ignored in traditional compliance analysis has a significant effect o...The compliance modeling is one of the most significant issues in the stage of preliminary design for parallel kinematic machine（PKM）. The gravity ignored in traditional compliance analysis has a significant effect on pose accuracy of tool center point（TCP） when a PKM is horizontally placed. By taking gravity into account, this paper presents a semi-analytical approach for compliance analysis of a 3-DOF spindle head named the A3 head. The architecture behind the A3 head is a 3-RPS parallel mechanism having one translational and two rotational movement capabilities, which can be employed to form the main body of a 5-DOF hybrid kinematic machine especially designed for high-speed machining of large aircraft components. The force analysis is carried out by considering both the externally applied wrench imposed upon the platform as well as gravity of all moving components. Then, the deflection analysis is investigated to establish the relationship between the deflection twist and compliances of all joints and links using semi-analytical method. The merits of this approach lie in that platform deflection twist throughout the entire task workspace can be evaluated in a very efficient manner. The effectiveness of the proposed approach is verified by the FEA and experiment at different configurations and the results show that the discrepancy of the compliances is less than 0.04 μm/N^-1 and that of the deformations is less than 10μm. The computational and experimental results show that the deflection twist induced by gravity forces of the moving components has significant bearings on pose accuracy of the platform, providing an informative guidance for the improvement of the current design. The proposed approach can be easily applied to the compliance analysis of PKM by considering gravitational effects and to evaluate the deformation caused by gravity throughout the entire workspace.展开更多
The well-distribution spindle Li Fe PO4(LFP)nanoparticles as cathode of lithium secondary batteries were synthesized by a solvothermal reaction route at low temperature(180 °C) in which the ascorbic acid was used...The well-distribution spindle Li Fe PO4(LFP)nanoparticles as cathode of lithium secondary batteries were synthesized by a solvothermal reaction route at low temperature(180 °C) in which the ascorbic acid was used as reducing agent. In order to guarantee that the p H values of thermal systems were not affected too much and the reducibility of the system was enhanced at the same time,glucose was chosen as an auxiliary reductant in this reaction. The obtained powders were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM),and laser particle analyzer. The results show that the carbon-coated uniform spindle olivine Li Fe PO4/C-glucose particles(glucose as auxiliary reductant, LFP/C-G) are prepared with the size 500–600 nm and without any impurity phases. Their electrochemical properties were evaluated by electrochemical impedance spectroscopy,cyclic voltammetry, and galvanostatic charge/discharge tests. LFP/C-G has a higher conductivity and better reversible capability than carbon-coated LFP(LFP/C). The highest discharge capacity of LFP/C-G is 161.3 mAh·g-1at0.1C and 108.6 mAh·g-1at 5.0C, respectively. The results imply that the neat crystal nanostructure of LFP/C-G has excellent capacity retention and cycling stability.The adding of glucose is the key factor for the welldistribution and neat crystal structure of nanoparticles,thus the electrochemical performances of materials are improved.展开更多
Motor reinnervation after repair of tibial nerve defects using autologous vein grafts in rats has previously been reported, but sensory reinnervation after the same repair has not been fully investigated. In this stud...Motor reinnervation after repair of tibial nerve defects using autologous vein grafts in rats has previously been reported, but sensory reinnervation after the same repair has not been fully investigated. In this study, partial sensory reinnervation of muscle spindles was observed after repair of lO-mm left tibial nerve defects using autologous vein grafts with end-to-end anasto- mosis in rats, and functional recovery was confirmed by electrophysiological studies. There were no significant differences in the number, size, or electrophysiological function of reinnervated muscle spindles between the two experimental groups. These findings suggest that repair of short nerve defects with autologous vein grafts provides comparable results to immediate end-to-end anastomosis in terms of sensory reinnervation of muscle spindles.展开更多
Hydrostatic spindles are increasingly used in precision machine tools. Thermal error is the key factor affecting the machining accuracy of the spindle, and research has focused on spindle thermal errors through examin...Hydrostatic spindles are increasingly used in precision machine tools. Thermal error is the key factor affecting the machining accuracy of the spindle, and research has focused on spindle thermal errors through examination of the influence of the temperature distribution, thermal deformation and spindle mode. However, seldom has any research investigated the thermal effects of the associated Couette flow. To study the heat transfer mechanism in spindle systems, the criterion of the heat transfer direction according to the temperature distribution of the Couette flow at different temperatures is deduced. The method is able to deal accurately with the significant phenomena occurring at every place where thermal energy flowed in such a spindle system. The variation of the motion error induced by thermal effects on a machine work-table during machining is predicated by establishing the thermo-mechanical error model of the hydrostatic spindle for a high precision machine tool. The flow state and thermal behavior of a hydrostatic spindle is analyzed with the evaluated heat power and the coefficients of the convective heat transfer over outer surface of the spindle are calculated, and the thermal influence on the oil film stiffness is evaluated. Thermal drift of the spindle nose is measured with an inductance micrometer, the thermal deformation data 1.35 μm after running for 4 h is consistent with the value predicted by the finite element analysis’s simulated result 1.28 μm, and this demonstrates that the simulation method is feasible. The thermal effects on the processing accuracy from the flow characteristics of the fluid inside the spindle are analyzed for the first time.展开更多
Although the role of oxidative stress in maternal aging and infertility has been suggested, the underlying mechanisms are not fully understood. The present study is designed to determine the relationship between mitoc...Although the role of oxidative stress in maternal aging and infertility has been suggested, the underlying mechanisms are not fully understood. The present study is designed to determine the relationship between mitochondrial function and spindle stability in metaphase II (MII) oocytes under oxidative stress. MII mouse oocytes were treated with H2O2 in the presence or absence of permeability transition pores (PTPs) blockers cyclosporin A (CsA). In addition, antioxidant N-acetylcysteine (NAC), F0/F1 synthase inhibitor oligomycin A, the mitochondria uncoupler carbonyl cyanide 4-trifluoro- methoxyphenylhydrazone (FCCP) or thapsigargin plus 2.5 mM Ca^2+ (Th+2.5 mM Ca^2+) were used in mechanistic studies. Morphologic analyses of oocyte spindles and chromosomes were performed and mitochondrial membrane potential (AWm), cytoplasmic free calcium concentration ([Ca^2+]c) and cytoplasmic ATP content within oocytes were also assayed. In a time- and H202 dose-dependent manner, disruption of meiotic spindles was found after oocytes were treated with H202, which was prevented by pre-treatment with NAC. Administration of H2O2 led to a dissipation of AWm, an increase in [Ca^2+]c and a decrease in cytoplasmic ATP levels. These detrimental responses of oocytes to H2O2 treatment could be blocked by pre-incubation with CsA. Similar to H2O2, both oligomycin A and FCCP dissipated AWm, decreased cytoplasmic ATP contents and disassembled MII oocyte spindles, while high [Ca^2+]c alone had no effects on spindle morphology. In conclusion, the decrease in mitochondria-derived ATP during oxidative stress may cause a disassembly of mouse MII oocyte spindles, presumably due to the opening of the mitochondrial PTPs.展开更多
文摘This paper gives an error analysis of radial motion measurement of ultra-precision spindle including nonlinearity error of capacitive displacement probes, misalignment error of probes, eccentric error of artifact ball and error induced by different error separating methods. Firstly, nonlinearity of a capacitive displacement probe targeting a spherical surface is investigated through experiment and the phenomena of fake displacement induced by lateral offset of the probe relative to an artifact ball?are?discussed. It is shown that the error motion in radial and axial direction and eccentric rotation of artifact ball will both induce lateral offset which causes a fake output of probes. Moreover, measurement error induced by angular positioning error for three famous error separating methods is detailed.
基金Supported by National Natural Science Foundation of China(Grant No.52475494)Zhejiang Provincial Natural Science Foundation of China(Grant No.LY22E050003)Fundamental Research Funds for the Provincial Universities of Zhejiang(Grant No.RF-A2020005).
文摘In the machining of high-end optical components,the aerostatic spindle error of an ultra-precision machine tool has a significant impact on the surface quality of the machined surfaces.The surfaces of many high-end optical components need to meet the extremely stringent requirements of the full-frequency band error,which poses significant challenge to the control of the aerostatic spindle error.In this research,we put forward an active control method for the frequency domain error of the aerostatic spindle based on acoustic levitation,in which the acousticmagnetism-fluid-solid multi-field coupling rotor dynamics modeling method of the aerostatic spindle was proposed and the corresponding multi-field coupling model was established.Through the numerical simulation and preliminary experiments,the influence law of acoustic levitation on the frequency domain error of the aerostatic spindle is obtained.The results showed that acoustic levitation can be used to control the frequency domain error of the aerostatic spindle to some extent,which verified the effectiveness of the proposed method.
基金Supported by National Natural Science Foundation of China,No.81960115,No.82160123 and No.82260124Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor(Guangxi Medical University),Ministry of Education,No.GKEZZ202107+1 种基金Guangxi Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor,No.GKE-ZZ202218Guangxi Science and Technology Program,No.AD25069077.
文摘BACKGROUND Hepatitis B virus(HBV)infection is a leading cause of global hepatocellular carcinoma(HCC).Conventional biomarkers such as alpha-fetoprotein(AFP)demonstrate suboptimal sensitivity and specificity.Emerging evidence suggests that serum extra spindle pole bodies like 1(ESPL1)protein and p53 antibody may improve diagnostic accuracy.AIM To assess and compare the diagnostic performance of serum ESPL1 protein and p53 antibody in HBV-related HCC(HBV-HCC).METHODS This case-control study from the First Affiliated Hospital of Guangxi Medical University enrolled 30 patients with chronic hepatitis B(CHB),30 with HBV-related liver cirrhosis(HBV-LC),55 with HBV-HCC,and 30 healthy controls.Serum ESPL1 protein and p53 antibody levels were quantified via ELISA.Diagnostic performance was evaluated using receiver operating characteristic(ROC)curve analysis,including sensitivity,specificity,and correlation with AFP.RESULTS Serum ESPL1 protein levels progressively increased across disease stages(CHB:89.9 ng/L;HBV-LC:188.83 ng/L;HBV-HCC:317.63 ng/L),with a significantly higher area under the ROC curve(AUC=0.917)than either p53 antibody(AUC=0.725)or AFP(AUC=0.678).p53 antibody levels were significantly elevated only in the HBVHCC group.ESPL1 demonstrated superior sensitivity and concordance with histopathological findings.A significant correlation between ESPL1 and p53 antibody levels was observed exclusively in the HBV-HCC group(r=0.320,P=0.017),suggesting potential interplay in malignant transformation.CONCLUSION Serum ESPL1 protein,a promising biomarker for early HBV-HCC detection,outperforms p53 antibody in diagnostic reliability.Higher ESPL1 levels correlate with increased HCC risk in chronic HBV patients.
文摘In order to minimize vibration and improve rotary precision of spindle, we apply active vibration control technique to ultra-precision turning machine based on the analysis of vibration characteristic of aerostatic bearing spindle. Using aerostatic bearing itself as actuator, the vibration of spindle is controlled by adjusting admission pressure respectively and by changing pressure distribution in the bearing. The experiments and simulations prove that this method can minimize the vibration of spindle effectively.
文摘BACKGROUND Metastatic cardiac tumors are known to occur more frequently than primary cardiac tumors,however,they often remain asymptomatic and are commonly dis-covered on autopsy.Malignant tumors with a relatively high frequency of cardiac metastasis include mesothelioma,melanoma,lung cancer,and breast cancer,whereas reports of esophageal cancer with cardiac metastasis are rare.CASE SUMMARY The case of a 60-year-old man who complained of dysphagia is presented.Upper gastrointestinal endoscopy showed a submucosal tumor-like elevated lesion in the esophagus causing stenosis.Contrast-enhanced computed tomography showed left atrial compression due to the esophageal tumor,multiple liver and lung metastases,and a left pleural effusion.Pathological examination of a biopsy speci-men from the esophageal tumor showed spindle-shaped cells,raising suspicion of esophageal sarcoma.The disease progressed rapidly,and systemic chemotherapy was deemed necessary,however,due to his poor general condition,adminis-tration of cytotoxic agents was considered difficult.Given his high Combined Positive Score,nivolumab was administered,however,the patient soon died from the disease.The autopsy confirmed spindle cell carcinoma(SCC)of the esophagus and cardiac metastasis with similar histological features.Cancer stem cell markers,ZEB1 and TWIST,were positive in both the primary tumor and the cardiac metastasis.CONCLUSION To the best of our knowledge,there have been no prior reports of cardiac metastasis of esophageal SCC.This case highlights our experience with a patient with esophageal SCC who progressed rapidly and died from the disease,with the autopsy examination showing cardiac metastasis.
基金supported by National Natural Science Foundation of China(32570854)Science and Technology Program of Guangzhou,China(2023A03J0258)Guangdong Basic and Applied Basic Research Foundation,China(2023B1515120027)。
文摘CtBP-interacting protein(CtIP)is known for its multifaceted roles in DNA repair and genomic stability,directing the homologous recombination-mediated DNA double-stranded break repair pathway via DNA end resection,an essential error-free repair process vital for genome stability.Mammalian oocytes are highly prone to DNA damage accumulation due to prolonged G2/prophase arrest.Here,we explore the functions of CtIP in meiotic cell cycle regulation via a mouse oocyte model.Depletion of CtIP by siRNA injection results in delayed germinal vesicle breakdown and failed polar body extrusion.Mechanistically,CtIP deficiency increases DNA damage and decreases the expression and nuclear entry of CCNB1,resulting in marked impairment of meiotic resumption,which can be rescued by exogenous CCNB1 overexpression.Furthermore,depletion of CtIP disrupts microtubule-organizing centers coalescence at spindle poles as indicated by failed accumulation ofγ-tubulin,p-Aurora kinase A,Kif2A,and TPX2,leading to abnormal spindle assembly and prometaphase arrest.These results provide valuable insights into the important roles of CtIP in the G2/M checkpoint and spindle assembly in mouse oocyte meiotic cell cycle regulation.
基金supported by Korea Electrotechnology Research Institute(KERI)Primary Research Program through the National Research Council of Science&Technology(NST)funded by the Ministry of Science and ICT(MSIT)in 2023(No.23A01021)the National Research Foundation of Korea(NRF)grant funded by the Korean Government(MSIT)(No.RS-2023-00278890).
文摘This study presents the development of an ultrasonic transducer with a radius horn for an ultrasonic milling spindle(UMS)system.The ultrasonic transducer was intended to have a working frequency of approximately 30 kHz.Two different materials were considered in the study:stainless steel(SS 316L)and titanium alloy(Ti-6Al-4V).Titanium alloy gave a higher resonance frequency(33 kHz)than stainless steel(30 kHz)under the same preload compression stress.An electromechanical impedance simulation was carried out to predict the impedance resonance frequency for both materials,and the effect of the overhanging toolbar was investigated.According to the electromechanical impedance simulation,the overhanging toolbar length affected the resonance frequency,and the error was less than 3%.Harmonic analysis confirmed that the damping ratio helps determine the resonance amplitude.Therefore,damping ratios of 0.015-0.020 and 0.005-0.020 were selected for stainless steel and titanium alloy,respectively,with an error of less than 1.5%.Experimental machining was also performed to assess the feasibility of ultrasonic-assisted milling;the result was a lesser cutting force and better surface topography of Al 6061.
基金National Key Research and Development Program of China(No.2023YFB3711100)National Natural Science Foundation of China(Grant Nos.52275458,52275207)Natural Science Foundation of Tianjin(Grant No.22JCZDJC00050)。
文摘Significant advancements in ultra-precision machining technology have forced a re-examination of the spindle perpendicularity errors'impact on the milled surface quality at the micro-nano scale.In this paper,a method of spindle precision adjustment is proposed to enhance surface finish quality.Sensitive errors in the machining process are identified using multi-body kinematic theory,with the milling process serving as an example.A two-degree-of-freedom(2-DOF)rotation platform is designed,optimized,and fabricated.The platform's static model is established based on elastic beam theory and verified by finite element analysis.Structural parameters are optimized via the response surface method in combination with the Pareto front.Experimental results reveal the effects of spindle speed,voltage amplitude,vibration frequency,cutting depth,and feed rate on the platform's modulation performance.The static modulation experiment shows that the perpendicularity error between the spindle and the guideway can be reduced from 92.5μrad to 0.25μrad.Finally,milling experiments show that the surface quality can be improved by 37.6%after spindle modulation.
基金supported by the National Science Foundation under Grant No.CMMI-1844821supported by the NSF through the University of Wisconsin Materials Research Science Center(Grant No.DMR-1720415).
文摘With the growing demand for the fabrication of microminiaturized components,a comprehensive understanding of material removal behavior during ultra-precision cutting has become increasingly significant.Single-crystal sapphire stands out as a promising material for microelectronic components,ultra-precision lenses,and semiconductor structures owing to its exceptional characteristics,such as high hardness,chemical stability,and optical properties.This paper focuses on understanding the mechanism responsible for generating anisotropic crack morphologies along various cutting orientations on four crystal planes(C-,R-,A-,and M-planes)of sapphire during ultra-precision orthogonal cutting.By employing a scanning electric microscope to examine the machined surfaces,the crack morphologies can be categorized into three distinct types on the basis of their distinctive features:layered,sculptured,and lateral.To understand the mechanism determining crack morphology,visualized parameters related to the plastic deformation and cleavage fracture parameters are utilized.These parameters provide insight into both the likelihood and direction of plastic deformation and fracture system activations.Analysis of the results shows that the formation of crack morphology is predominantly influenced by the directionality of crystallographic fracture system activation and by the interplay between fracture and plastic deformation system activations.
基金The Natural Science Foundation of Higher EducationInstitutions of Jiangsu Province (No.04KJB510073).
文摘Due to the non-linearity behavior of the precision positioning system, an accurate mathematical control model is difficult to set up, a novel control method for ultra-precision alignment is presented. This method relies on neural network and alignment marks that are in the form of 100μm pitch gratings. The 0-th order Moire signals＇ intensity and its intensity rate are chosen as input variables of the neural network. The characteristics of the neural network make it possible to perform self-training and self-adjusting so as to achieve automatic precision alignment. A neural network model for precision positioning is set up. The model is composed of three neural layers, i.e. input layer, hidden layer and output layer. Driving signal is obtained by mapping Moire signals＇ intensity and its intensity rate. The experimental results show that neural network control for precision positioning can effectively improve positioning speed with high accuracy. It has the advantages of fast, stable response and good robustness. The device based on neural network can achieve the positioning accuracy of ± 0. 5μm.
文摘A novel method for automatic ultra-precision alignment is presented.This method relies on the modified Moiré technique,and alignment marks are used in the form of gratings.The modified Moiré technique can effectively improve detecting sensitivity of signals and simplify the control system by using only one pair of laser-Moiré sensors.We present the mathematical model and simulation results of diffracting two gratings.The effect of various parameters on Moiré signals is studied theoretically and experimentally,and the results are found to be consistent.A computer controlled alignment device using one pair of Moiré sensors is designed.The device can achieve a fully automatic precision alignment by the modified Moiré signal.The experimental result shows that the alignment device can obtain the resolution of 5 nm and the positioning accuracy of ±0 5 μm.
文摘An applicable method to control regenerative cutting chatter automatically based on the optimal regulation of spindle speed is introduced. The optimal value of the phase shift angle of the regenerative chatter signal between the two successive cuts is 270°. The cutting process can be adjusted from the unstable region to stable one whenever regenerative chatter occurs if the phase shift angle is kept 270° by the optimal regulation of spindle speed. The theoretical analysis and the experimental results prove that the optimal regulation of spindle speed can effectively control regenerative cutting chatter. In addition, a reliablelly optimal control system of reliable spindle speed is presented. There is no need for system identification of the machine tool, and it is easy to put this regenerative chatter control method into practice, so the method has excellent application prospect.
文摘In this paper we address the dynamics of compensation cutting process from both Laplace s frequency domain and the time domain of the first time, using the two computer aided analyzing softwares: MATLAB and SIMULINK. Theoretical analysis and simulation experiments firstly show that not only the systematical stiffness of workpiece, spindle and tools, but also the regenerated coefficient affects the compensation displacement effect. The results show that the SREC is practicable in reality to decease the spindle induced errors in many engineering applications such as hard boring through simulation and the preliminary experiment results.
基金supported by the National Natural Science Foundation of China (No. 30971424)
文摘To date, the medium and long-term space flight is urgent in need and has become a major task of our manned space flight program. There is no doubt that medium and long-term space flight has serious damaging impact upon human physiological systems. For instance, atrophy of the lower limb anti-gravity muscle can be induced during the space flight. Muscle atrophy significantly affects the flight of astronauts in space. Most importantly, it influences the precise manipulation of the astronauts and their response capacity to emergencies on returning to the atmosphere from space. Muscle atrophy caused by weightlessness may also seriously disrupt the normal life and ＇work of the astronauts during the re-adaptation period. Here we summarize the corresponding research concentrating on weightlessness-induced changes of muscular structure and function. By combining research on muscle pain, which is a common clinical pain disease, we further provide a hypothesis concerning a dynamic feedback model of ＂weightlessness condition → muscular atrophy ←→ muscle pain＂. This may be useful to explore the neural mechanisms underlying the occurrence and development of muscular atrophy and muscle pain, through the key study of muscle spindle, and furthermore provide more effective therapy for clinical treatment.
基金Supported by National Natural Science Foundation of China(Grant No.51135008)PhD Programs Foundation of Ministry of Education of China(Grant No.20110032130006)
文摘The compliance modeling is one of the most significant issues in the stage of preliminary design for parallel kinematic machine（PKM）. The gravity ignored in traditional compliance analysis has a significant effect on pose accuracy of tool center point（TCP） when a PKM is horizontally placed. By taking gravity into account, this paper presents a semi-analytical approach for compliance analysis of a 3-DOF spindle head named the A3 head. The architecture behind the A3 head is a 3-RPS parallel mechanism having one translational and two rotational movement capabilities, which can be employed to form the main body of a 5-DOF hybrid kinematic machine especially designed for high-speed machining of large aircraft components. The force analysis is carried out by considering both the externally applied wrench imposed upon the platform as well as gravity of all moving components. Then, the deflection analysis is investigated to establish the relationship between the deflection twist and compliances of all joints and links using semi-analytical method. The merits of this approach lie in that platform deflection twist throughout the entire task workspace can be evaluated in a very efficient manner. The effectiveness of the proposed approach is verified by the FEA and experiment at different configurations and the results show that the discrepancy of the compliances is less than 0.04 μm/N^-1 and that of the deformations is less than 10μm. The computational and experimental results show that the deflection twist induced by gravity forces of the moving components has significant bearings on pose accuracy of the platform, providing an informative guidance for the improvement of the current design. The proposed approach can be easily applied to the compliance analysis of PKM by considering gravitational effects and to evaluate the deformation caused by gravity throughout the entire workspace.
基金financially supported by the National Natural Science Foundation of China(No.51203041)the Higher School in Hebei Province Science and Technology Research Project(No.ZH201206)the Scientific Research Foundation of Ministry Education for Returned Overseas Students
文摘The well-distribution spindle Li Fe PO4(LFP)nanoparticles as cathode of lithium secondary batteries were synthesized by a solvothermal reaction route at low temperature(180 °C) in which the ascorbic acid was used as reducing agent. In order to guarantee that the p H values of thermal systems were not affected too much and the reducibility of the system was enhanced at the same time,glucose was chosen as an auxiliary reductant in this reaction. The obtained powders were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM),and laser particle analyzer. The results show that the carbon-coated uniform spindle olivine Li Fe PO4/C-glucose particles(glucose as auxiliary reductant, LFP/C-G) are prepared with the size 500–600 nm and without any impurity phases. Their electrochemical properties were evaluated by electrochemical impedance spectroscopy,cyclic voltammetry, and galvanostatic charge/discharge tests. LFP/C-G has a higher conductivity and better reversible capability than carbon-coated LFP(LFP/C). The highest discharge capacity of LFP/C-G is 161.3 mAh·g-1at0.1C and 108.6 mAh·g-1at 5.0C, respectively. The results imply that the neat crystal nanostructure of LFP/C-G has excellent capacity retention and cycling stability.The adding of glucose is the key factor for the welldistribution and neat crystal structure of nanoparticles,thus the electrochemical performances of materials are improved.
基金supported by the Medical Science and Technology Innovation Foundation of Nanjing Military Area Command of Chinese PLA in 2013,ZX22
文摘Motor reinnervation after repair of tibial nerve defects using autologous vein grafts in rats has previously been reported, but sensory reinnervation after the same repair has not been fully investigated. In this study, partial sensory reinnervation of muscle spindles was observed after repair of lO-mm left tibial nerve defects using autologous vein grafts with end-to-end anasto- mosis in rats, and functional recovery was confirmed by electrophysiological studies. There were no significant differences in the number, size, or electrophysiological function of reinnervated muscle spindles between the two experimental groups. These findings suggest that repair of short nerve defects with autologous vein grafts provides comparable results to immediate end-to-end anastomosis in terms of sensory reinnervation of muscle spindles.
基金supported by National Natural Science Foundation of China (Grant Nos. 51105005, 51275014)Ministry of Education of China (Grant No. 20111103120002)
文摘Hydrostatic spindles are increasingly used in precision machine tools. Thermal error is the key factor affecting the machining accuracy of the spindle, and research has focused on spindle thermal errors through examination of the influence of the temperature distribution, thermal deformation and spindle mode. However, seldom has any research investigated the thermal effects of the associated Couette flow. To study the heat transfer mechanism in spindle systems, the criterion of the heat transfer direction according to the temperature distribution of the Couette flow at different temperatures is deduced. The method is able to deal accurately with the significant phenomena occurring at every place where thermal energy flowed in such a spindle system. The variation of the motion error induced by thermal effects on a machine work-table during machining is predicated by establishing the thermo-mechanical error model of the hydrostatic spindle for a high precision machine tool. The flow state and thermal behavior of a hydrostatic spindle is analyzed with the evaluated heat power and the coefficients of the convective heat transfer over outer surface of the spindle are calculated, and the thermal influence on the oil film stiffness is evaluated. Thermal drift of the spindle nose is measured with an inductance micrometer, the thermal deformation data 1.35 μm after running for 4 h is consistent with the value predicted by the finite element analysis’s simulated result 1.28 μm, and this demonstrates that the simulation method is feasible. The thermal effects on the processing accuracy from the flow characteristics of the fluid inside the spindle are analyzed for the first time.
文摘Although the role of oxidative stress in maternal aging and infertility has been suggested, the underlying mechanisms are not fully understood. The present study is designed to determine the relationship between mitochondrial function and spindle stability in metaphase II (MII) oocytes under oxidative stress. MII mouse oocytes were treated with H2O2 in the presence or absence of permeability transition pores (PTPs) blockers cyclosporin A (CsA). In addition, antioxidant N-acetylcysteine (NAC), F0/F1 synthase inhibitor oligomycin A, the mitochondria uncoupler carbonyl cyanide 4-trifluoro- methoxyphenylhydrazone (FCCP) or thapsigargin plus 2.5 mM Ca^2+ (Th+2.5 mM Ca^2+) were used in mechanistic studies. Morphologic analyses of oocyte spindles and chromosomes were performed and mitochondrial membrane potential (AWm), cytoplasmic free calcium concentration ([Ca^2+]c) and cytoplasmic ATP content within oocytes were also assayed. In a time- and H202 dose-dependent manner, disruption of meiotic spindles was found after oocytes were treated with H202, which was prevented by pre-treatment with NAC. Administration of H2O2 led to a dissipation of AWm, an increase in [Ca^2+]c and a decrease in cytoplasmic ATP levels. These detrimental responses of oocytes to H2O2 treatment could be blocked by pre-incubation with CsA. Similar to H2O2, both oligomycin A and FCCP dissipated AWm, decreased cytoplasmic ATP contents and disassembled MII oocyte spindles, while high [Ca^2+]c alone had no effects on spindle morphology. In conclusion, the decrease in mitochondria-derived ATP during oxidative stress may cause a disassembly of mouse MII oocyte spindles, presumably due to the opening of the mitochondrial PTPs.
