To assess the value of magnetic resonance elastography(MRE) in detecting advanced fibrosis/cirrhosis in autoimmune hepatitis(AIH).METHODS In this retrospective study, 36 patients(19 treated and 17 untreated) with hist...To assess the value of magnetic resonance elastography(MRE) in detecting advanced fibrosis/cirrhosis in autoimmune hepatitis(AIH).METHODS In this retrospective study, 36 patients(19 treated and 17 untreated) with histologically confirmed AIH and liver biopsy performed within 3 mo of MRE were identified at a tertiary care referral center. Liver stiffness(LS) with MRE was calculated by a radiologist, and inflammation grade and fibrosis stage in liver biopsy was assessed by a pathologist in a blinded fashion. Two radiologistsevaluated morphological features of cirrhosis on conventional magnetic resonance imaging(MRI). Accuracy of MRE was compared to laboratory markers and MRI for detection of advanced fibrosis/cirrhosis.RESULTS Liver fibrosis stages of 0, 1, 2, 3 and 4 were present in 4, 6, 7, 6 and 13 patients respectively. There were no significant differences in distribution of fibrosis stage and inflammation grade between treated and untreated patient groups. LS with MRE demonstrated stronger correlation with liver fibrosis stage in comparison to laboratory markers for chronic liver disease(r = 0.88 vs-0.48-0.70). A trend of decreased mean LS in treated patients compared to untreated patients was observed(3.7 k Pa vs 3.84 k Pa) but was not statistically significant. MRE had an accuracy/sensitivity/specificity/positive predictive value/negative predictive value of 0.97/90%/100%/100%/90% and 0.98/92.3%/96%/92.3%/96% for detection of advanced fibrosis and cirrhosis, respectively. The performance of MRE was significantly better than laboratory tests for detection of advanced fibrosis(0.97 vs 0.53-0.80, P < 0.01), and cirrhosis(0.98 vs 0.58-0.80, P < 0.01) and better than conventional MRI for diagnosis of cirrhosis(0.98 vs 0.78, P = 0.002).CONCLUSION MRE is a promising modality for detection of advanced fibrosis and cirrhosis in patients with AIH with superior diagnostic accuracy compared to laboratory assessment and MRI.展开更多
Hard carbon material is one of the most promising anode materials for potassium ion batteries(PIBs)due to its distinct disordered and non-expandable framework.However,the intrinsically disordered microarchitecture of ...Hard carbon material is one of the most promising anode materials for potassium ion batteries(PIBs)due to its distinct disordered and non-expandable framework.However,the intrinsically disordered microarchitecture of hard carbon results in low electric conductivity and poor rate capability.Herein,nitrogendoped and partially graphitized hard carbons(NGHCs)derived from commercial coordination compound precursor-ethylenediaminetetraacetic acid(EDTA)disodium cobalt salt hydrate are designed and prepared as high-performance PIBs anode materials.By means of a facile annealing method,nitrogen elements and graphitic domains can be controllably introduced to NGHCs.The resulting NGHCs show structural merits of mesoporous construction,nitrogen doping and homogeneous graphitic domains,which ensures fast kinetics and electron transportation.Applying in anode for PIBs,NGHCs exhibit robust rate capability with high reversible capacity of 298.8 m Ah g^-1 at 50 m A g^-1,and stable cycle stability of 137.6 mAh g^-1 at 500 m A g^-1 after 1000 cycles.Moreover,the ex situ Raman spectra reveal a mixture"adsorption-intercalation mechanism"for potassium storage of NGHCs.More importantly,full PIBs by pairing with perylenetetracarboxylic dianhydride(PTCDA)cathode demonstrate the promising potential of practical application.In terms of commercial precursor,facile synthesis and long cycle lifespan,NGHCs represent a brilliant prospect for practical large-scale applications.展开更多
The length of fexible manipulators with a telescopic arm alters during movement.The dynamic parameters of telescopic fexible manipulators exhibit signifcant time-varying characteristics owing to variations in length.W...The length of fexible manipulators with a telescopic arm alters during movement.The dynamic parameters of telescopic fexible manipulators exhibit signifcant time-varying characteristics owing to variations in length.With an increase in the manipulators’length,the nonlinear terms caused by fexibility in the manipulators’dynamic equations cannot be ignored.The time-varying characteristics and nonlinear terms of telescopic fexible manipulators cause fuctuations in rotation angles,which afect the operation accuracy of end-efectors.In this study,a control strategy based on a combination of fuzzy adjustment and an RBF neural network is utilized to improve the control accuracy of fexible telescopic manipulators.First,the dynamic equation of the manipulators is established using the assumed mode method and Lagrange’s principle,and the infuence of nonlinear terms is analyzed.Subsequently,a combined control strategy is proposed to suppress the fuctuation of the rotation angle in telescopic fexible manipulators.The variation ranges of the feedforward PD controller parameters are determined by the pole placement strategy and length of the manipulators.Fuzzy rules are utilized to adjust the controller parameters in real-time.The RBF neural network is utilized to identify and compensate the uncertain part of the dynamic model of the fexible manipulators.The uncertain part comprises time-varying parameters and nonlinear terms.Finally,numerical simulations and prototype experiments prove the efectiveness of the combined control strategy.The results prove that the proposed control strategy has a smaller standard deviation of errors.Therefore,the combined control strategy is more suitable for telescopic fexible manipulators,which can efectively improve the control accuracy of rotation angles.展开更多
Introduction: Hepatic magnetic resonance elastography (MRE) allows for noninvasive assessment of liver fibrosis. The purpose of this study was to evaluate the usefulness of MRE in detecting and quantifying liver fibro...Introduction: Hepatic magnetic resonance elastography (MRE) allows for noninvasive assessment of liver fibrosis. The purpose of this study was to evaluate the usefulness of MRE in detecting and quantifying liver fibrosis in patients with rheumatoid arthritis (RA) who have received methotrexate (MTX). Methods: The association between mean liver stiffness value as determined by MRE and variables of interest was determined. The decision for a liver biopsy in participants with an abnormal liver stiffness was made based on clinical judgment. Results: Sixty-five RA patients were enrolled. Mean liver stiffness value by MRE was abnormal in 7 patients, suggestive of hepatic injury. As a result of findings from the MRE, biopsies were performed in 5 patients and all correlated with elevated liver stiffness values. Elevated mean liver stiffness values were associated with body mass index (BMI) (OR = 1.18 per 1 kg/m2;95% CI: 1.03, 1.36;p = 0.017). Neither the total MTX dose nor the duration of MTX treatment was associated with mean liver stiffness value (p = 0.51 and P = 0.20, respectively). Conclusion: MRE provides a reliable, non-invasive assessment of liver fibrosis in patients with RA receiving MTX. Patients with RA receiving MTX who have an elevated BMI may be at increased risk for chronic hepatic injury, regardless of MTX cumulative dose or duration of treatment.展开更多
In space operation,flexible manipulators and gripper mechanisms have been widely used because of light weight and flexibility.However,the vibration caused by slender structures in manipulators and the parameter pertur...In space operation,flexible manipulators and gripper mechanisms have been widely used because of light weight and flexibility.However,the vibration caused by slender structures in manipulators and the parameter perturbation caused by the uncertainty derived from grasping mass variation cannot be ignored.The existence of vibration and parameter perturbation makes the rotation control of flexible manipulators difficult,which seriously affects the operation accuracy of manipulators.What’s more,the complex dynamic coupling brings great challenges to the dynamics modeling and vibration analysis.To solve this problem,this paper takes the space flexible manipulator with an underactuated hand(SFMUH)as the research object.The dynamics model considering flexibility,multiple nonlinear elements and disturbance torque is established by the assumed modal method(AMM)and Hamilton’s principle.A dynamic modeling simplification method is proposed by analyzing the nonlinear terms.What’s more,a sliding mode control(SMC)method combined with the radial basis function(RBF)neural network compensation is proposed.Besides,the control law is designed using a saturation function in the control method to weaken the chatter phenomenon.With the help of neural networks to identify the uncertainty composition in the SFMUH,the tracking accuracy is improved.The results of ground control experiments verify the advantages of the control method for vibration suppression of the SFMUH.展开更多
Pericardial barrier destruction,inflammatory cell infiltration,and fibrous tissue hyperplasia,trigger adhesions after cardiac surgery.There are few anti-adhesion materials that are both functional and sutureable for p...Pericardial barrier destruction,inflammatory cell infiltration,and fibrous tissue hyperplasia,trigger adhesions after cardiac surgery.There are few anti-adhesion materials that are both functional and sutureable for pericardial reconstruction.Besides,a few studies have reported on the mechanism of preventing pericardial adhesion.Herein,a functional barrier membrane with sutureability was developed via a modified electrospinning method.It was composed of poly(L-lactide-co-caprolactone)(PLCL)nanofibers,poly(vinyl alcohol)(PVA)aerogel,and melatonin,named PPMT.The PPMT had a special microstructure manifested as a staggered arrangement of nanofibers on the surface and a layered macroporous aerogel structure in a cross-section.Besides providing the porosity and hydrophilicity obtained from PVA,the structure also had suitable mechanical properties for stitching due to the addition of PLCL nanofibers.Furthermore,it inhibited the proliferation of fibroblasts by suppressing the activation of Fas and P53,and achieved anti-inflammatory effects by affecting the activity of inflammatory cells and reducing the release of pro-inflammatory factors,such as interleukin 8(IL-8)and tumor necrosis factorα(TNF-α).Finally,in vivo transplantation showed that it up-regulated the expression of matrix metalloproteinase-1(MMP1)and tissue inhibitor of metalloproteinase-1(TIMP1),and down-regulated the expression of Vinculin and transforming growth factorβ(TGF-β)in the myocardium,thereby reducing the formation of adhesions.Collectively,these results demonstrate a great potential of PPMT membrane for practical application to anti-adhesion.展开更多
Gelation kinetics is important in tailoring chemically crosslinked hydrogel-based injectable adhesives for different applications.However,the regulation of gelation rate is usually limited to varying the gel precursor...Gelation kinetics is important in tailoring chemically crosslinked hydrogel-based injectable adhesives for different applications.However,the regulation of gelation rate is usually limited to varying the gel precursor and/or crosslinker concentration,which cannot reach a fine level and inevitably alters the physical properties of hydrogels.Amidation reactions are widely used to synthesize hydrogel adhesives.In this work,we propose a traditional Chinese medicine(Borax)-input strategy to tune the gelation rate of amidation reaction triggered systems.Borax provides an initial basic buffer environment to promote the deprotonation process of amino groups and accelerate this reaction.By using a tissue adhesive model PEG-lysozyme(PEG-LZM),the gelation time can be modulated from seconds to minutes with varying Borax concentrations,while the physical properties remain constant.Moreover,the antibacterial ability can be improved due to the bioactivity of Borax.The hydrogel precursors can be regulated to solidify instantly to close the bleeding wound at emergency.Meanwhile,they can also be customized to match the flowing time in the catheter,thereby facilitating minimally invasive tissue sealing.Because this method is easily operated,we envision Borax adjusted amidation-type hydrogel has a promising prospect in clinical application.展开更多
基金Supported by National Institutes of Health,No.EB001981 to Ehman RL and No.EB017197 to Yin Mthe National Natural Science Foundation of China,No.81271562 to Wang J
文摘To assess the value of magnetic resonance elastography(MRE) in detecting advanced fibrosis/cirrhosis in autoimmune hepatitis(AIH).METHODS In this retrospective study, 36 patients(19 treated and 17 untreated) with histologically confirmed AIH and liver biopsy performed within 3 mo of MRE were identified at a tertiary care referral center. Liver stiffness(LS) with MRE was calculated by a radiologist, and inflammation grade and fibrosis stage in liver biopsy was assessed by a pathologist in a blinded fashion. Two radiologistsevaluated morphological features of cirrhosis on conventional magnetic resonance imaging(MRI). Accuracy of MRE was compared to laboratory markers and MRI for detection of advanced fibrosis/cirrhosis.RESULTS Liver fibrosis stages of 0, 1, 2, 3 and 4 were present in 4, 6, 7, 6 and 13 patients respectively. There were no significant differences in distribution of fibrosis stage and inflammation grade between treated and untreated patient groups. LS with MRE demonstrated stronger correlation with liver fibrosis stage in comparison to laboratory markers for chronic liver disease(r = 0.88 vs-0.48-0.70). A trend of decreased mean LS in treated patients compared to untreated patients was observed(3.7 k Pa vs 3.84 k Pa) but was not statistically significant. MRE had an accuracy/sensitivity/specificity/positive predictive value/negative predictive value of 0.97/90%/100%/100%/90% and 0.98/92.3%/96%/92.3%/96% for detection of advanced fibrosis and cirrhosis, respectively. The performance of MRE was significantly better than laboratory tests for detection of advanced fibrosis(0.97 vs 0.53-0.80, P < 0.01), and cirrhosis(0.98 vs 0.58-0.80, P < 0.01) and better than conventional MRI for diagnosis of cirrhosis(0.98 vs 0.78, P = 0.002).CONCLUSION MRE is a promising modality for detection of advanced fibrosis and cirrhosis in patients with AIH with superior diagnostic accuracy compared to laboratory assessment and MRI.
基金support of the Innovation Program of Central South University(No.2018zzts139)。
文摘Hard carbon material is one of the most promising anode materials for potassium ion batteries(PIBs)due to its distinct disordered and non-expandable framework.However,the intrinsically disordered microarchitecture of hard carbon results in low electric conductivity and poor rate capability.Herein,nitrogendoped and partially graphitized hard carbons(NGHCs)derived from commercial coordination compound precursor-ethylenediaminetetraacetic acid(EDTA)disodium cobalt salt hydrate are designed and prepared as high-performance PIBs anode materials.By means of a facile annealing method,nitrogen elements and graphitic domains can be controllably introduced to NGHCs.The resulting NGHCs show structural merits of mesoporous construction,nitrogen doping and homogeneous graphitic domains,which ensures fast kinetics and electron transportation.Applying in anode for PIBs,NGHCs exhibit robust rate capability with high reversible capacity of 298.8 m Ah g^-1 at 50 m A g^-1,and stable cycle stability of 137.6 mAh g^-1 at 500 m A g^-1 after 1000 cycles.Moreover,the ex situ Raman spectra reveal a mixture"adsorption-intercalation mechanism"for potassium storage of NGHCs.More importantly,full PIBs by pairing with perylenetetracarboxylic dianhydride(PTCDA)cathode demonstrate the promising potential of practical application.In terms of commercial precursor,facile synthesis and long cycle lifespan,NGHCs represent a brilliant prospect for practical large-scale applications.
基金Supported by National Natural Science Foundation of China(Grant No.51875092)National Key Research and Development Project of China(Grant No.2020YFB2007802)+1 种基金Natural Science Foundation of Ningxia Province(Grant No.2020AAC03279)Fundamental Research Funds for the Central Universities(Grant No.N2103025).
文摘The length of fexible manipulators with a telescopic arm alters during movement.The dynamic parameters of telescopic fexible manipulators exhibit signifcant time-varying characteristics owing to variations in length.With an increase in the manipulators’length,the nonlinear terms caused by fexibility in the manipulators’dynamic equations cannot be ignored.The time-varying characteristics and nonlinear terms of telescopic fexible manipulators cause fuctuations in rotation angles,which afect the operation accuracy of end-efectors.In this study,a control strategy based on a combination of fuzzy adjustment and an RBF neural network is utilized to improve the control accuracy of fexible telescopic manipulators.First,the dynamic equation of the manipulators is established using the assumed mode method and Lagrange’s principle,and the infuence of nonlinear terms is analyzed.Subsequently,a combined control strategy is proposed to suppress the fuctuation of the rotation angle in telescopic fexible manipulators.The variation ranges of the feedforward PD controller parameters are determined by the pole placement strategy and length of the manipulators.Fuzzy rules are utilized to adjust the controller parameters in real-time.The RBF neural network is utilized to identify and compensate the uncertain part of the dynamic model of the fexible manipulators.The uncertain part comprises time-varying parameters and nonlinear terms.Finally,numerical simulations and prototype experiments prove the efectiveness of the combined control strategy.The results prove that the proposed control strategy has a smaller standard deviation of errors.Therefore,the combined control strategy is more suitable for telescopic fexible manipulators,which can efectively improve the control accuracy of rotation angles.
文摘Introduction: Hepatic magnetic resonance elastography (MRE) allows for noninvasive assessment of liver fibrosis. The purpose of this study was to evaluate the usefulness of MRE in detecting and quantifying liver fibrosis in patients with rheumatoid arthritis (RA) who have received methotrexate (MTX). Methods: The association between mean liver stiffness value as determined by MRE and variables of interest was determined. The decision for a liver biopsy in participants with an abnormal liver stiffness was made based on clinical judgment. Results: Sixty-five RA patients were enrolled. Mean liver stiffness value by MRE was abnormal in 7 patients, suggestive of hepatic injury. As a result of findings from the MRE, biopsies were performed in 5 patients and all correlated with elevated liver stiffness values. Elevated mean liver stiffness values were associated with body mass index (BMI) (OR = 1.18 per 1 kg/m2;95% CI: 1.03, 1.36;p = 0.017). Neither the total MTX dose nor the duration of MTX treatment was associated with mean liver stiffness value (p = 0.51 and P = 0.20, respectively). Conclusion: MRE provides a reliable, non-invasive assessment of liver fibrosis in patients with RA receiving MTX. Patients with RA receiving MTX who have an elevated BMI may be at increased risk for chronic hepatic injury, regardless of MTX cumulative dose or duration of treatment.
基金supported by the National Natural Science Foundation of China(No.52275090)the Fundamental Research Funds for the Central Universities(No.N2103025)+1 种基金the National Key Research and Development Program of China(No.2020YFB2007802)the Applied Basic Research Program of Liaoning Province(No.2023JH2/101300159)。
文摘In space operation,flexible manipulators and gripper mechanisms have been widely used because of light weight and flexibility.However,the vibration caused by slender structures in manipulators and the parameter perturbation caused by the uncertainty derived from grasping mass variation cannot be ignored.The existence of vibration and parameter perturbation makes the rotation control of flexible manipulators difficult,which seriously affects the operation accuracy of manipulators.What’s more,the complex dynamic coupling brings great challenges to the dynamics modeling and vibration analysis.To solve this problem,this paper takes the space flexible manipulator with an underactuated hand(SFMUH)as the research object.The dynamics model considering flexibility,multiple nonlinear elements and disturbance torque is established by the assumed modal method(AMM)and Hamilton’s principle.A dynamic modeling simplification method is proposed by analyzing the nonlinear terms.What’s more,a sliding mode control(SMC)method combined with the radial basis function(RBF)neural network compensation is proposed.Besides,the control law is designed using a saturation function in the control method to weaken the chatter phenomenon.With the help of neural networks to identify the uncertainty composition in the SFMUH,the tracking accuracy is improved.The results of ground control experiments verify the advantages of the control method for vibration suppression of the SFMUH.
基金The National Natural Science Fund of China(81873923)Shanghai Science and Technology Development Fund(20Y11910600,18441901900)supported this study.
文摘Pericardial barrier destruction,inflammatory cell infiltration,and fibrous tissue hyperplasia,trigger adhesions after cardiac surgery.There are few anti-adhesion materials that are both functional and sutureable for pericardial reconstruction.Besides,a few studies have reported on the mechanism of preventing pericardial adhesion.Herein,a functional barrier membrane with sutureability was developed via a modified electrospinning method.It was composed of poly(L-lactide-co-caprolactone)(PLCL)nanofibers,poly(vinyl alcohol)(PVA)aerogel,and melatonin,named PPMT.The PPMT had a special microstructure manifested as a staggered arrangement of nanofibers on the surface and a layered macroporous aerogel structure in a cross-section.Besides providing the porosity and hydrophilicity obtained from PVA,the structure also had suitable mechanical properties for stitching due to the addition of PLCL nanofibers.Furthermore,it inhibited the proliferation of fibroblasts by suppressing the activation of Fas and P53,and achieved anti-inflammatory effects by affecting the activity of inflammatory cells and reducing the release of pro-inflammatory factors,such as interleukin 8(IL-8)and tumor necrosis factorα(TNF-α).Finally,in vivo transplantation showed that it up-regulated the expression of matrix metalloproteinase-1(MMP1)and tissue inhibitor of metalloproteinase-1(TIMP1),and down-regulated the expression of Vinculin and transforming growth factorβ(TGF-β)in the myocardium,thereby reducing the formation of adhesions.Collectively,these results demonstrate a great potential of PPMT membrane for practical application to anti-adhesion.
基金supported by National Natural Science Foundation of China(grant number:31922041,51621002,11932012 , 21875066)the science and technology innovation project of Shanghai Science and Technique Committee(18441908300)the Fundamental Research Funds for the Central Universities(SLD 00202006,JKVD12001032,JKVD12001002,50321041916015).
文摘Gelation kinetics is important in tailoring chemically crosslinked hydrogel-based injectable adhesives for different applications.However,the regulation of gelation rate is usually limited to varying the gel precursor and/or crosslinker concentration,which cannot reach a fine level and inevitably alters the physical properties of hydrogels.Amidation reactions are widely used to synthesize hydrogel adhesives.In this work,we propose a traditional Chinese medicine(Borax)-input strategy to tune the gelation rate of amidation reaction triggered systems.Borax provides an initial basic buffer environment to promote the deprotonation process of amino groups and accelerate this reaction.By using a tissue adhesive model PEG-lysozyme(PEG-LZM),the gelation time can be modulated from seconds to minutes with varying Borax concentrations,while the physical properties remain constant.Moreover,the antibacterial ability can be improved due to the bioactivity of Borax.The hydrogel precursors can be regulated to solidify instantly to close the bleeding wound at emergency.Meanwhile,they can also be customized to match the flowing time in the catheter,thereby facilitating minimally invasive tissue sealing.Because this method is easily operated,we envision Borax adjusted amidation-type hydrogel has a promising prospect in clinical application.
