A multi-resolution rectangular shell element with membrane-bending based on the Kirchhoff-Love theory is proposed. The multi-resolution analysis （MRA） framework is formulated out of a mutually nesting displacement s...A multi-resolution rectangular shell element with membrane-bending based on the Kirchhoff-Love theory is proposed. The multi-resolution analysis （MRA） framework is formulated out of a mutually nesting displacement subspace sequence, whose basis functions are constructed of scaling and shifting on the element domain of basic node shape functions. The basic node shape functions are constructed from shifting to other three quadrants around a specific node of a basic element in one quadrant and joining the corresponding node shape functions of four elements at the specific node. The MRA endows the proposed element with the resolution level （RL） to adjust the element node number, thus modulating structural analysis accuracy accordingly. The node shape functions of Kronecker delta property make the treatment of element boundary condition quite convenient and enable the stiffness matrix and the loading column vectors of the proposed element to be automatically acquired through quadraturing around nodes in RL adjusting. As a result, the traditional 4-node rectangular shell element is a mono-resolution one and also a special case of the proposed element. The accuracy of a structural analysis is actually determined by the RL, not by the mesh. The simplicity and clarity of node shape function formulation with the Kronecker delta property, and the rational MRA enable the proposed element method to be implemented more rationally, easily and efficiently than the conventional mono-resolution rectangular shell element method or other corresponding MRA methods.展开更多
Objective:Diabetic retinopathy(DR) is the retinal consequence of chronic progressive diabetic microvascular leakage and occlusion.Non-proliferating diabetic retinopathy(NPDR) is the early stage of DR.It eventually occ...Objective:Diabetic retinopathy(DR) is the retinal consequence of chronic progressive diabetic microvascular leakage and occlusion.Non-proliferating diabetic retinopathy(NPDR) is the early stage of DR.It eventually occurs to some degree in all patients with diabetes mellitus.In recent years,many clinical trials have shown that Compound Danshen Dripping Pill(CDDP) may be associated with the improvement of NPDR symptoms.The aim of this study was to quantitatively summarize the association between CDDP and the therapeutic effects of NPDR.Methods:It was conducted that a systematic literature search of Pub Med,Web of Science,CNKI,VIP and Wanfang Data updated in June 2020 with the following search terms:"diabetic retinopathy° or"retinopathy° or "DR° or "NPDR°,in combination with "Compound Danshen Dripping Pill° or "Salvia miltiorrhiza° or "Danshen°.Risk ratio(RR) and weighted mean difference(WMD) with their 95% confidence interval(CI) was calculated between treatment and control groups.The sensitivity analyses were undertaken by removing each individual study when high heterogeneity appeared.Subgroup analysis,Metaregression,and publication bias analysis were also conducted.The strength of evidence was evaluated with the Grading of Recommendation,Assessment,Development,and Evaluation(GRADE) method.Results:Twenty-six RCTs involving 2047 subjects were included to conduct a Meta-analysis after screening the studies,extracting the data,and assessing the study quality.The Stata15.0 software was utilized for processing.Meta-analysis indicated that curative effects of treatment group with CDDP was significantly better than control [RR = 0.54,95% CI(0.40,0.73);moderate-quality evidence].In addition,the results showed that CDDP was significantly associated with improving retinal hemorrhages[WMD =-0.62,95% CI(-0.78,-0.46);low-quality evidence],the vision [WMD = 0.14,and 95% CI(0.09,0.19),low-quality evidence],fundus fluorescence angiography [RR = 0.37 and 95% CI(0.23,0.60);low-quality evidence],reduction of retinal microaneurysm [WMD =-3.74 and 95% CI(-4.38,-3.11);moderate-quality evidence],hemangioma volume [WMD =-3.15,95%CI(-3.45,-2.85);moderate-quality evidence],macular thickness [WMD =-5.52,95%CI =(-64.27,-48.78);low-quality evidence],mean defect [WMD =-1.65 and 95% CI(-1.95,-1.34);very low-quality evidence],fasting blooding glucose [WMD =-0.95,95% CI(-1.19,-0.70);low-quality evidence),hemoglobin A1c[WMD =-0.62,95% CI(-0.93,-0.30);low-quality evidence],high sensitive C reaction protein[WMD =-5.66,95% CI(-8.01,-3.31);low-quality evidence].Sensitivity,subgroup,and Metaregression analyses were also assessed.Conclusion:The study demonstrated that CDDP has beneficial clinical effects for treating NPDR and improve the vision.Moreover,it indicated that oral CDDP in NPDR patients led to significant regulation of serum level of fasting blooding glucose,hemoglobin A1c and high sensitive C reaction protein,which was associated with the pathogenesis of NPDR.However,high-quality and large randomized clinical trials will be needed to prove the consequence in future.展开更多
Based on the basic mechanical properties of geomaterials,it was proven that the Drucker Postulate and the classical theory of plasticity can not be applied to geomaterials.Moreover,several basic problems of plastic th...Based on the basic mechanical properties of geomaterials,it was proven that the Drucker Postulate and the classical theory of plasticity can not be applied to geomaterials.Moreover,several basic problems of plastic theory of geomaterials were discussed.Based on the strict theoretical analysis,the following have been proven:the single yield surface model based on the classical theory of plasticity is unsuitable for geomaterials whether the rule of associated flow is applied or not;the yield surface of geomaterials is not unique,and its number is the same as the freedoms of plastic strain increment;the yield surface is not convex;and the rule of associated flow is unsuitable for geomaterials.展开更多
基金financial support by the Open Foundation of Chongqing Key Laboratory of Geomechanics and Geoenvironment Protection(Logistical Engineering University)(No.GKLGGP 2013-02)
文摘A multi-resolution rectangular shell element with membrane-bending based on the Kirchhoff-Love theory is proposed. The multi-resolution analysis （MRA） framework is formulated out of a mutually nesting displacement subspace sequence, whose basis functions are constructed of scaling and shifting on the element domain of basic node shape functions. The basic node shape functions are constructed from shifting to other three quadrants around a specific node of a basic element in one quadrant and joining the corresponding node shape functions of four elements at the specific node. The MRA endows the proposed element with the resolution level （RL） to adjust the element node number, thus modulating structural analysis accuracy accordingly. The node shape functions of Kronecker delta property make the treatment of element boundary condition quite convenient and enable the stiffness matrix and the loading column vectors of the proposed element to be automatically acquired through quadraturing around nodes in RL adjusting. As a result, the traditional 4-node rectangular shell element is a mono-resolution one and also a special case of the proposed element. The accuracy of a structural analysis is actually determined by the RL, not by the mesh. The simplicity and clarity of node shape function formulation with the Kronecker delta property, and the rational MRA enable the proposed element method to be implemented more rationally, easily and efficiently than the conventional mono-resolution rectangular shell element method or other corresponding MRA methods.
基金supported by the National Science and Technology Major Project for Significant New Drugs Development(2017ZX09301005)
文摘Objective:Diabetic retinopathy(DR) is the retinal consequence of chronic progressive diabetic microvascular leakage and occlusion.Non-proliferating diabetic retinopathy(NPDR) is the early stage of DR.It eventually occurs to some degree in all patients with diabetes mellitus.In recent years,many clinical trials have shown that Compound Danshen Dripping Pill(CDDP) may be associated with the improvement of NPDR symptoms.The aim of this study was to quantitatively summarize the association between CDDP and the therapeutic effects of NPDR.Methods:It was conducted that a systematic literature search of Pub Med,Web of Science,CNKI,VIP and Wanfang Data updated in June 2020 with the following search terms:"diabetic retinopathy° or"retinopathy° or "DR° or "NPDR°,in combination with "Compound Danshen Dripping Pill° or "Salvia miltiorrhiza° or "Danshen°.Risk ratio(RR) and weighted mean difference(WMD) with their 95% confidence interval(CI) was calculated between treatment and control groups.The sensitivity analyses were undertaken by removing each individual study when high heterogeneity appeared.Subgroup analysis,Metaregression,and publication bias analysis were also conducted.The strength of evidence was evaluated with the Grading of Recommendation,Assessment,Development,and Evaluation(GRADE) method.Results:Twenty-six RCTs involving 2047 subjects were included to conduct a Meta-analysis after screening the studies,extracting the data,and assessing the study quality.The Stata15.0 software was utilized for processing.Meta-analysis indicated that curative effects of treatment group with CDDP was significantly better than control [RR = 0.54,95% CI(0.40,0.73);moderate-quality evidence].In addition,the results showed that CDDP was significantly associated with improving retinal hemorrhages[WMD =-0.62,95% CI(-0.78,-0.46);low-quality evidence],the vision [WMD = 0.14,and 95% CI(0.09,0.19),low-quality evidence],fundus fluorescence angiography [RR = 0.37 and 95% CI(0.23,0.60);low-quality evidence],reduction of retinal microaneurysm [WMD =-3.74 and 95% CI(-4.38,-3.11);moderate-quality evidence],hemangioma volume [WMD =-3.15,95%CI(-3.45,-2.85);moderate-quality evidence],macular thickness [WMD =-5.52,95%CI =(-64.27,-48.78);low-quality evidence],mean defect [WMD =-1.65 and 95% CI(-1.95,-1.34);very low-quality evidence],fasting blooding glucose [WMD =-0.95,95% CI(-1.19,-0.70);low-quality evidence),hemoglobin A1c[WMD =-0.62,95% CI(-0.93,-0.30);low-quality evidence],high sensitive C reaction protein[WMD =-5.66,95% CI(-8.01,-3.31);low-quality evidence].Sensitivity,subgroup,and Metaregression analyses were also assessed.Conclusion:The study demonstrated that CDDP has beneficial clinical effects for treating NPDR and improve the vision.Moreover,it indicated that oral CDDP in NPDR patients led to significant regulation of serum level of fasting blooding glucose,hemoglobin A1c and high sensitive C reaction protein,which was associated with the pathogenesis of NPDR.However,high-quality and large randomized clinical trials will be needed to prove the consequence in future.
文摘Based on the basic mechanical properties of geomaterials,it was proven that the Drucker Postulate and the classical theory of plasticity can not be applied to geomaterials.Moreover,several basic problems of plastic theory of geomaterials were discussed.Based on the strict theoretical analysis,the following have been proven:the single yield surface model based on the classical theory of plasticity is unsuitable for geomaterials whether the rule of associated flow is applied or not;the yield surface of geomaterials is not unique,and its number is the same as the freedoms of plastic strain increment;the yield surface is not convex;and the rule of associated flow is unsuitable for geomaterials.
