B-stability and B-convergence theories of Runge-Kutta methods for nonlinear stiff Volterra func-tional differential equations (VFDEs) are established which provide unified theoretical foundation for the studyof Runge-...B-stability and B-convergence theories of Runge-Kutta methods for nonlinear stiff Volterra func-tional differential equations (VFDEs) are established which provide unified theoretical foundation for the studyof Runge-Kutta methods when applied to nonlinear stiff initial value problems (IVPs) in ordinary differentialequations (ODEs), delay differential equations (DDEs), integro-differential equations (IDEs) and VFDEs ofother type which appear in practice.展开更多
A series of stability, contractivity and asymptotic stability results of the solutions to nonlinear stiff Volterra functional differential equations (VFDEs) in Banach spaces is obtained, which provides the unified the...A series of stability, contractivity and asymptotic stability results of the solutions to nonlinear stiff Volterra functional differential equations (VFDEs) in Banach spaces is obtained, which provides the unified theoretical foundation for the stability analysis of solutions to nonlinear stiff problems in ordinary differential equations(ODEs), delay differential equations(DDEs), integro-differential equations(IDEs) and VFDEs of other type which appear in practice.展开更多
AIM To compare the results of arthroscopic capsular release with intra-articular steroid injections in patients of frozen shoulder.METHODS Fifty-six patients with frozen shoulder were randomised to one of two treatmen...AIM To compare the results of arthroscopic capsular release with intra-articular steroid injections in patients of frozen shoulder.METHODS Fifty-six patients with frozen shoulder were randomised to one of two treatment groups: Group 1, complete 360 degree arthroscopic capsular release and group 2, intra-articular corticosteroid injection(40 mg methyl prednisolone acetate). Both groups were put on active and passive range of motion exercises following the intervention. The outcome parameters were visual analogue scale(VAS) score for pain, range of motion and Constant score which were measured at baseline, 4, 8, 12, 16 and 20 wk after intervention.RESULTS All the parameters improved in both the groups. The mean VAS score improved significantly more in the group 1 as compared to group 2 at 8 wk. This greater improvement was maintained at 20 wk with P value of 0.007 at 8 wk, 0.006 at 12 wk, 0.006 at 16 wk and 0.019 at 20 wk. The Constant score showed a more significant improvement in group 1 compared to group 2 at 4 wk, which was again maintained at 20 wk with P value of 0.01 at 4, 8, 12 and 16 wk. The gain in abduction movement was statistically significantly more in arthroscopy group with P value of 0.001 at 4, 8, 12, 16 wk and 0.005 at 20 wk. The gain in external rotation was statistically significantly more in arthroscopy group with P value of 0.007 at 4 wk, 0.001 at 8, 12, and 16 wk and 0.003 at 20 wk. There was no statistically significant difference in extension and internal rotation between the two groups at any time. CONCLUSION Arthroscopic capsular release provides subjective and objective improvement earlier than intra-articular steroid injection.展开更多
A class of efficient parallel multivalue hybrid methods for stiff differential equations are presented,which are all extremely stable at infinity, A-stable for orders 1-3 and A(α)-stable for orders 4-8. Eachmethod of...A class of efficient parallel multivalue hybrid methods for stiff differential equations are presented,which are all extremely stable at infinity, A-stable for orders 1-3 and A(α)-stable for orders 4-8. Eachmethod of the class can be performed parallelly using two processors with each processor having almost thesame computational amount per integration step as a backward differentiation formula (BDF) of the same orderwith the same stepsize performed in serial, whereas the former has not only much better stability propertiesbut also a computational accuracy higher than the corresponding BDF. Theoretical analysis and numericalexperiments show that the methods constructed in this paper are superior in many respects not only to BDFsbut also to some other commonly used methods.展开更多
BACKGROUND The diagnostic specificity of conventional ultrasound for breast non-mass lesions(NMLs)is low at approximately 21%-43%.Shear wave elastography(SWE)can distinguish benign from malignant lesions by evaluating...BACKGROUND The diagnostic specificity of conventional ultrasound for breast non-mass lesions(NMLs)is low at approximately 21%-43%.Shear wave elastography(SWE)can distinguish benign from malignant lesions by evaluating the internal and peripheral stiffness.SWE has good reproducibility and high diagnostic efficacy.However,there are very few independent studies on the diagnostic value of SWE in breast NMLs.AIM To determine the value of SWE in the differential diagnosis of breast NMLs.METHODS This study enrolled a total of 118 patients with breast NMLs who underwent SWE examinations in the Beijing Shijitan Hospital Affiliated to Capital Medical University and The Second Hospital of Shandong University from January 2019 to January 2020.The internal elastic parameters of the lesions were recorded,including maximum(Emax),mean(Emean)and minimum elastic values and the standard deviation.The following peripheral parameters were noted:Presence of a“stiff rim”sign;Emax,and Emean elasticity values within 1 mm,1.5 mm,2 mm,2.5 mm and 3 mm from the edge of NMLs.The receiver operating characteristic curve of each parameter was drawn,and the areas under the curve were calculated.RESULTS Emax,Emean and elastic values,and the standard deviation of the internal elastic values in malignant NMLs were significantly higher than those in benign NMLs(P<0.05).The percentage with the“stiff rim”sign in malignant NMLs was significantly higher than that in the benign group(P<0.05),and Emax and Emean at the shell of 1 mm,1.5 mm,2 mm,2.5 mm and 3 mm in the malignant group were all higher than those in the benign group(P<0.05).Of the surrounding elasticity values,Emax of the shell at 2.5 mm in malignant NMLs had maximum areas under the curve of 0.900,and the corresponding sensitivity and specificity were 94.57%and 85.86%,respectively.CONCLUSION The“stiff rim”sign and multiple quantitative elastic values within and around the lesion had good diagnostic performance in the differential diagnosis of breast NMLs.Emax in peripheral tissue ha展开更多
One-dimensional(1D)aramid nanofiber(ANF)based nanocomposite films have drawn increasing attentions in various applications due to their excellent mechanical properties and impressive chemical and thermal stabilities.H...One-dimensional(1D)aramid nanofiber(ANF)based nanocomposite films have drawn increasing attentions in various applications due to their excellent mechanical properties and impressive chemical and thermal stabilities.However,the large-area fabrication of aramid nanocomposite films with ultrastrong mechanical properties under mild conditions remains a great challenge.Here we present a facile superspreading-assisted strategy to produce aramid nanofiber based oriented layered nanocomposites using phase inversion process that occurs at the fully swollen hydrogel surfaces.The nanocomposite films based on ANF,carboxylation carbon tube(CNT–COOH),poly(vinyl alcohol)(PVA),and MXene nanosheet exhibit a tensile strength of up to 870.8±85 MPa,a Young’s modulus of 21.8±2.2 GPa,and outstanding toughness(up to 43.2±4.6 MJ/m^(3)),which are much better than those conventional aramid nanofiber based materials.Electrical conductivity of our nanocomposite films reaches the maximum of about 1100 S/m.The fabulous mechanical properties combination and continuous production capability render our strategy representing a promising direction for the development of high-performance nanocomposites.展开更多
Cementations formed in geological timescale are observed in various stiff clays.A micromechanical stress strain model is developed for modeling the effect of cementation on the deformation behavior of stiff clay.The p...Cementations formed in geological timescale are observed in various stiff clays.A micromechanical stress strain model is developed for modeling the effect of cementation on the deformation behavior of stiff clay.The proposed approach considers explicitly cementations at intercluster contacts,which is different from conventional model.The concept of inter-cluster bonding is introduced to account for an additional cohesion in shear sliding and a higher yield stress in normal compression.A damage law for inter-cluster bonding is proposed at cluster contacts for the debonding process during mechanical loading.The model is used to simulate numerous stress-path tests on Vallericca stiff clay.The applicability of the present model is evaluated through comparisons between the predicted and the measured results.In order to explain the stress-induced anisotropy arising from externally applied load,the evolution of local stresses and local strains at inter-cluster planes are discussed.展开更多
Stiff Person Syndrome (SPS) is a rare autoimmune disease related to the lack of inhibition of excitatory neurons in the central nervous system leading to multiple motor dysfunction and symptoms due to uncontrolled mot...Stiff Person Syndrome (SPS) is a rare autoimmune disease related to the lack of inhibition of excitatory neurons in the central nervous system leading to multiple motor dysfunction and symptoms due to uncontrolled motor neuron firing. The pathophysiology of the disease is not completely understood;however, high titers of Glutamic acid decarboxylase antibodies (anti-GAD Ab) have been found in such patients, which leads to its high association with the disease. We present a case of a 52-year-old female with a 20-year history of ongoing gait and balance issues. She is diagnosed with multiple conditions, including stiff person syndrome (GAD+), spinocerebellar ataxia with epilepsy, systemic lupus erythematosus, type 1 diabetes mellitus, IgA deficiency, hypothyroidism, and pernicious anemia. She presented in our institution with a history of a recent fall from a wheelchair. We review the case presentation and association of anti-GAD antibodies with stiff person syndrome and its treatment.展开更多
Polymer composite fibers with superior properties such as excellent combined strength and toughness and biocompatibility can be used in high-tech applications of braided protective devices and smart wearable,however t...Polymer composite fibers with superior properties such as excellent combined strength and toughness and biocompatibility can be used in high-tech applications of braided protective devices and smart wearable,however the research of high-performance polymer composite fiber remains in the infant stage.Here we present a strategy to produce strong and tough anisotropic polymer nanocomposite fibers with orientedly aligned salt rods using mechanical stretching-assisted salting-out treatment.The prepared nanocomposite fibers have a tensile strength of up to 786±2.7 MPa and an elongation at break of 81%,and the anisotropic fibers exhibit good transmission of mechanical vibration in the longitudinal direction with high resolution.During the fabrication process,the salt builds up into oriented rods during the directional salting process,and the polymer is confined to the 150 nm domain between the rods after the solvent is completely evaporated,giving the nanocomposite fibers superior mechanical properties.The presented strategy can be applied to the continuous mass production of nanocomposite fibers and is also generalizable to other polymer nanocomposites,which could extend the applicability of nanocomposite fibers to conditions involving more demanding mechanical loading and mechanical vibration transmission.展开更多
文摘B-stability and B-convergence theories of Runge-Kutta methods for nonlinear stiff Volterra func-tional differential equations (VFDEs) are established which provide unified theoretical foundation for the studyof Runge-Kutta methods when applied to nonlinear stiff initial value problems (IVPs) in ordinary differentialequations (ODEs), delay differential equations (DDEs), integro-differential equations (IDEs) and VFDEs ofother type which appear in practice.
基金This work was supported by the National High-Tech ICF Committee in Chinathe National Natural Science Foundation of China(Grant No.10271100).
文摘A series of stability, contractivity and asymptotic stability results of the solutions to nonlinear stiff Volterra functional differential equations (VFDEs) in Banach spaces is obtained, which provides the unified theoretical foundation for the stability analysis of solutions to nonlinear stiff problems in ordinary differential equations(ODEs), delay differential equations(DDEs), integro-differential equations(IDEs) and VFDEs of other type which appear in practice.
文摘AIM To compare the results of arthroscopic capsular release with intra-articular steroid injections in patients of frozen shoulder.METHODS Fifty-six patients with frozen shoulder were randomised to one of two treatment groups: Group 1, complete 360 degree arthroscopic capsular release and group 2, intra-articular corticosteroid injection(40 mg methyl prednisolone acetate). Both groups were put on active and passive range of motion exercises following the intervention. The outcome parameters were visual analogue scale(VAS) score for pain, range of motion and Constant score which were measured at baseline, 4, 8, 12, 16 and 20 wk after intervention.RESULTS All the parameters improved in both the groups. The mean VAS score improved significantly more in the group 1 as compared to group 2 at 8 wk. This greater improvement was maintained at 20 wk with P value of 0.007 at 8 wk, 0.006 at 12 wk, 0.006 at 16 wk and 0.019 at 20 wk. The Constant score showed a more significant improvement in group 1 compared to group 2 at 4 wk, which was again maintained at 20 wk with P value of 0.01 at 4, 8, 12 and 16 wk. The gain in abduction movement was statistically significantly more in arthroscopy group with P value of 0.001 at 4, 8, 12, 16 wk and 0.005 at 20 wk. The gain in external rotation was statistically significantly more in arthroscopy group with P value of 0.007 at 4 wk, 0.001 at 8, 12, and 16 wk and 0.003 at 20 wk. There was no statistically significant difference in extension and internal rotation between the two groups at any time. CONCLUSION Arthroscopic capsular release provides subjective and objective improvement earlier than intra-articular steroid injection.
基金This work was supported by the National High-Tech ICF Committee in China and the National Natural Science Foundation of China (Grant No. 19871070).
文摘A class of efficient parallel multivalue hybrid methods for stiff differential equations are presented,which are all extremely stable at infinity, A-stable for orders 1-3 and A(α)-stable for orders 4-8. Eachmethod of the class can be performed parallelly using two processors with each processor having almost thesame computational amount per integration step as a backward differentiation formula (BDF) of the same orderwith the same stepsize performed in serial, whereas the former has not only much better stability propertiesbut also a computational accuracy higher than the corresponding BDF. Theoretical analysis and numericalexperiments show that the methods constructed in this paper are superior in many respects not only to BDFsbut also to some other commonly used methods.
文摘BACKGROUND The diagnostic specificity of conventional ultrasound for breast non-mass lesions(NMLs)is low at approximately 21%-43%.Shear wave elastography(SWE)can distinguish benign from malignant lesions by evaluating the internal and peripheral stiffness.SWE has good reproducibility and high diagnostic efficacy.However,there are very few independent studies on the diagnostic value of SWE in breast NMLs.AIM To determine the value of SWE in the differential diagnosis of breast NMLs.METHODS This study enrolled a total of 118 patients with breast NMLs who underwent SWE examinations in the Beijing Shijitan Hospital Affiliated to Capital Medical University and The Second Hospital of Shandong University from January 2019 to January 2020.The internal elastic parameters of the lesions were recorded,including maximum(Emax),mean(Emean)and minimum elastic values and the standard deviation.The following peripheral parameters were noted:Presence of a“stiff rim”sign;Emax,and Emean elasticity values within 1 mm,1.5 mm,2 mm,2.5 mm and 3 mm from the edge of NMLs.The receiver operating characteristic curve of each parameter was drawn,and the areas under the curve were calculated.RESULTS Emax,Emean and elastic values,and the standard deviation of the internal elastic values in malignant NMLs were significantly higher than those in benign NMLs(P<0.05).The percentage with the“stiff rim”sign in malignant NMLs was significantly higher than that in the benign group(P<0.05),and Emax and Emean at the shell of 1 mm,1.5 mm,2 mm,2.5 mm and 3 mm in the malignant group were all higher than those in the benign group(P<0.05).Of the surrounding elasticity values,Emax of the shell at 2.5 mm in malignant NMLs had maximum areas under the curve of 0.900,and the corresponding sensitivity and specificity were 94.57%and 85.86%,respectively.CONCLUSION The“stiff rim”sign and multiple quantitative elastic values within and around the lesion had good diagnostic performance in the differential diagnosis of breast NMLs.Emax in peripheral tissue ha
基金supported by the National Key Research and Development Program of China(No.2022YFA1503000)the National Natural Science Foundation of China(Nos.22161142021 and 22175010).
文摘One-dimensional(1D)aramid nanofiber(ANF)based nanocomposite films have drawn increasing attentions in various applications due to their excellent mechanical properties and impressive chemical and thermal stabilities.However,the large-area fabrication of aramid nanocomposite films with ultrastrong mechanical properties under mild conditions remains a great challenge.Here we present a facile superspreading-assisted strategy to produce aramid nanofiber based oriented layered nanocomposites using phase inversion process that occurs at the fully swollen hydrogel surfaces.The nanocomposite films based on ANF,carboxylation carbon tube(CNT–COOH),poly(vinyl alcohol)(PVA),and MXene nanosheet exhibit a tensile strength of up to 870.8±85 MPa,a Young’s modulus of 21.8±2.2 GPa,and outstanding toughness(up to 43.2±4.6 MJ/m^(3)),which are much better than those conventional aramid nanofiber based materials.Electrical conductivity of our nanocomposite films reaches the maximum of about 1100 S/m.The fabulous mechanical properties combination and continuous production capability render our strategy representing a promising direction for the development of high-performance nanocomposites.
基金supported by the Shanghai Pujiang Talent People Project(11PJ1405700)the National Science Funds for Distinguished Young Scholars(51025932)
文摘Cementations formed in geological timescale are observed in various stiff clays.A micromechanical stress strain model is developed for modeling the effect of cementation on the deformation behavior of stiff clay.The proposed approach considers explicitly cementations at intercluster contacts,which is different from conventional model.The concept of inter-cluster bonding is introduced to account for an additional cohesion in shear sliding and a higher yield stress in normal compression.A damage law for inter-cluster bonding is proposed at cluster contacts for the debonding process during mechanical loading.The model is used to simulate numerous stress-path tests on Vallericca stiff clay.The applicability of the present model is evaluated through comparisons between the predicted and the measured results.In order to explain the stress-induced anisotropy arising from externally applied load,the evolution of local stresses and local strains at inter-cluster planes are discussed.
文摘Stiff Person Syndrome (SPS) is a rare autoimmune disease related to the lack of inhibition of excitatory neurons in the central nervous system leading to multiple motor dysfunction and symptoms due to uncontrolled motor neuron firing. The pathophysiology of the disease is not completely understood;however, high titers of Glutamic acid decarboxylase antibodies (anti-GAD Ab) have been found in such patients, which leads to its high association with the disease. We present a case of a 52-year-old female with a 20-year history of ongoing gait and balance issues. She is diagnosed with multiple conditions, including stiff person syndrome (GAD+), spinocerebellar ataxia with epilepsy, systemic lupus erythematosus, type 1 diabetes mellitus, IgA deficiency, hypothyroidism, and pernicious anemia. She presented in our institution with a history of a recent fall from a wheelchair. We review the case presentation and association of anti-GAD antibodies with stiff person syndrome and its treatment.
基金supported by the National Key Research and Development Project(No.2022YFA1503000)the National Natural Science Foundation of China(Nos.22161142021 and 22175010).
文摘Polymer composite fibers with superior properties such as excellent combined strength and toughness and biocompatibility can be used in high-tech applications of braided protective devices and smart wearable,however the research of high-performance polymer composite fiber remains in the infant stage.Here we present a strategy to produce strong and tough anisotropic polymer nanocomposite fibers with orientedly aligned salt rods using mechanical stretching-assisted salting-out treatment.The prepared nanocomposite fibers have a tensile strength of up to 786±2.7 MPa and an elongation at break of 81%,and the anisotropic fibers exhibit good transmission of mechanical vibration in the longitudinal direction with high resolution.During the fabrication process,the salt builds up into oriented rods during the directional salting process,and the polymer is confined to the 150 nm domain between the rods after the solvent is completely evaporated,giving the nanocomposite fibers superior mechanical properties.The presented strategy can be applied to the continuous mass production of nanocomposite fibers and is also generalizable to other polymer nanocomposites,which could extend the applicability of nanocomposite fibers to conditions involving more demanding mechanical loading and mechanical vibration transmission.
