Objective: To evaluate the accuracy of glomerular filtration rate formula by comparising the CKD-EPI 2009 formula and the modified Modified MDRD formula with the 99mTc-DTPA double-phase plasma method as "gold sta...Objective: To evaluate the accuracy of glomerular filtration rate formula by comparising the CKD-EPI 2009 formula and the modified Modified MDRD formula with the 99mTc-DTPA double-phase plasma method as "gold standard" respectively. Methods: Totally 166 patients diognosed as chronic kidney disease (CKD) were enrolled. The 99mTc-DTPA double-plasma method (rGFR) was used as the "gold standard". The CKD-EPI 2009 formula and the modified MDRD formula were used to calculate eGFR. Statistical software was used to analyze the correlation between the calculated values of the two formulas and the gold standard value and the bias. Then we evaluated the accuracy of the two GFR formulas. Results: Among the CKD stage 1 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (13.9911.45;20.1815.90);both formulas were weakly correlated with the gold standard (correlation coefficients were 0.216, 0.229, P<0.01, respectively);The probability that the bias of the calculated value of the CKD-EPI 2009 formula less than 15%, 30%, and 50% of the gold standard value is smaller. Among the CKD stage 2 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (12.748.45;15.6811.01);both formulas were moderately correlated with the gold standard (correlation coefficients were 0.568, 0.581, P<0.01, respectively);The probability that the bias of the calculated value of the CKD-EPI 2009 formula less than 15%, 30%, and 50% of the gold standard value is smaller. Among the CKD stage 3 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (12.6410.27;12.8810.97), and both formulas were strongly correlated with the gold standard (correlation coefficients were 0.664, 0.670, P<0.01, respectively);The probability that the bias of the calculated value of the Modified MDRD formula less than 15%, 30%, and 50% of the gold standard value is smaller. Among the CKD stage 4 to 5 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (5.585.36;5.945.20);The CKD-EPI 2009 formula and the Modified MDRD formula were strongly correlated with the gold standard (correlation coefficient r was 0.808. 0.802, P<0.01, respectively);The probability of the bias of the calculated value of the CKD-EPI 2009 formula less than 15%, 30%, and 50% of the gold standard value is smaller. In patients with decreased renal function with GFR <60 ml/min, the sensitivity and positive predictive value of the CKD-EPI 2009 formula for the diagnosis of "decreased renal function"were higher, and the specificity was comparable. Conclusion: 1. When the renal function is only slightly decreased, the accuracy of the two formulas is not good. In this condition, the CKD-EPI 2009 formula is more accurate and recommended. 2. It is necessary to further improve the current formulas especialy when it comes to value the slightly declined renal function;3. When we try to identify the stage of CKD patients, only based on eGFR may cause misclassification, it is recommended to combine the cause-GFR-albuminuria staging to assess the stage of CKD;4. The current formulas have limitations.in the case that requires a highly accurate assessment of GFR, the 99mTc-DTPA dual plasma method is recommended.展开更多
Objective To investigate the effect of modified Leweiyin Formula(MLF)on key glycolytic regulatory targets in the gastric mucosa of rats with chronic atrophic gastritis(CAG)based on the phosphatidylinositol 3-kinase(PI...Objective To investigate the effect of modified Leweiyin Formula(MLF)on key glycolytic regulatory targets in the gastric mucosa of rats with chronic atrophic gastritis(CAG)based on the phosphatidylinositol 3-kinase(PI3K)/protein kinase B(AKT)/mammalian target of rapamycin(mTOR)signalingpathway.Methods The CAG rat model was induced using a combination of free drinking of 1-methyl-3-nitro-1-nitrosoguanidine(MNNG),oral administration of sodium salicylate,and an irregular feeding schedule.After modeling,except for the blank group,the remaining rats were randomly divided into the model group,Vitacoenzyme group,Chinese medicine(CM)low-dose group(6.3 g/kg),and CM high-dose group(25.2 g/kg),with 6 rats in each group.Rats in the normal group and the model group were gavaged daily with sterilized water.Each group received daily interventions for 28 days.HE staining was used to observe pathological changes of gastric mucosa.Alisin Blue-Periodic Acid Schiff(ABPAS)stainingwas used to detect the intestinal metaplasia.The changes of gastric mucosal epithelial cells were observe by Scanning electron microscopy(SEM).The mRNA expressions of glucose transporter 1(Glutl),hexokinase 2(HK2),pyruvate kinase M2(PKM2),and lactate dehydrogenase A(LDHA)were detected using qRT-PCR.The protein expressions of Glutl,HK2,PKM2,LDHA,PI3K,AKT,and mTOR were detected using Western Blot.Results Compared with the blank group,the model group showed decreased body weight(P<0.01),reduced food intake,lethargy,and pathological changes in the gastric mucosa,including atrophy and intestinal metaplasia.mRNA and protein expressions of Glutl,HK2,PKM2,and LDHA increased(P<0.05,P<0.01),the protein expressions of PI3K,AKT,and mTOR increased in the model group(P<0.01).Compared with the model group,the body weight of rats in all intervention groups increased(P<0.01),and their food intake,body weight,and mental state were all improved;the Vitacoenzyme group and the CM low-dose group,as well as the CM high-dose group,all repaired the gastric mucosal damage in CAG model rats from a pathological perspective and alleviated intestinal metaplasia.Compared with the model group,the levels of Glutl,HK2,and PKM2 mRNA reduced in all intervention groups(P<0.01),and the level of LDHA mRNA decreased in the CM high-dose group(P<0.01).Additionally,the protein expressions of PKM2,LDHA,Glutl,HK2,PI3K,and mTOR reduced in the CM low-dose and high-dose groups(P<0.05,P<0.01),AKT protein expressions decreased in the CM high-dose group(P<0.01).Conclusion MLF may treat chronic atrophic gastritis by down-regulating key glycolytic targets(Glutl,HK2,PKM2,and LDHA)through inhibition of the PI3K/AKT/mTOR pathway.展开更多
An error analysis of the dynamic shear modulus of stiff specimens from tests performed by a new resonant column device developed by the Institute of Engineering Mechanics, China was conducted. A modified approach for ...An error analysis of the dynamic shear modulus of stiff specimens from tests performed by a new resonant column device developed by the Institute of Engineering Mechanics, China was conducted. A modified approach for calculating the dynamic shear modulus of the stiff specimens is presented. The error formula of the tests was deduced and parameters that impact the accuracy of the test were identified. Using six steel specimens with known standard stiffness as a base, a revised dynamic shear modulus calculation for stiff specimens was formulated by comparing three of the models. The maximum error between the test results and the calculated results shown by curves from both the free-vibration and the resonant-vibration tests is less than 6%. The free-vibration and resonant-vibration tests for three types of stiff samples with a known modulus indicate that the maximum deviation between the actual and the tested value using the modified approach were less than 10%. As a result, the modified approach presented here is shown to be reliable and the new device can be used for testing dynamic shear modulus of any stiff materials at low shear strain levels展开更多
The quarter-circular caisson breakwater （QCB） is a new type of breakwater, and it can be applied in deepwater. The stability of QCB under wave force action can be enhanced, and the rubble mound engineering can be le...The quarter-circular caisson breakwater （QCB） is a new type of breakwater, and it can be applied in deepwater. The stability of QCB under wave force action can be enhanced, and the rubble mound engineering can be less than that of semi-circular breakwaters in deepwater. In order to study the wave force distribution acting on the QCB, to find wave force formula for this type of breakwater, firstly in this paper, the distribution characteristics of the horizontal force, the downward vertical force and the uplift force on the breakwater were gotten based on physical model wave flume experiments and on the analysis of the wave pressure experimental data. Based on a series of physical model tests acted by irregular waves, a kind of calculation method, which was modified by Goda formula, was proposed to carry out the wave force on the QCB. Secondly, the reliability method with correlated variables was adopted to analyze the QCB, considering the high correlation between wave forces or moments. Utilizing the observed wave data in engineering field, the reliability index and failure probability of QCB were obtained. Finally, a factor Q=0.9 is given to modify the zero pressure height above SWL of QCB, and wave force partial coefficient 1.34 to the design expressions of QCB for anti-sliding, as well as 1.67 for anti-overturning, were presented.展开更多
Several researchers have dealt with the one-dimensional fractional heat conduction equation in the last decades,but as far as we know,no one has investigated such a problem from the perspective of developing suitable ...Several researchers have dealt with the one-dimensional fractional heat conduction equation in the last decades,but as far as we know,no one has investigated such a problem from the perspective of developing suitable fractional-order methods.This has actually motivated us to address this problem by the way of establishing a proper fractional approach that involves employing a combination of a novel fractional difference formula to approximate the Caputo differentiator of orderαcoupled with the modified three-point fractional formula to approximate the Caputo differentiator of order 2α,where 0<α≤1.As a result,the fractional heat conduction equation is then reexpressed numerically using the aforementioned formulas,and by dividing the considered mesh into multiple nodes,a system is generated and algebraically solved with the aid of MATLAB.This would allow us to obtain the desired approximate solution for the problem at hand.展开更多
Using the complex variable method,an elastic analytical solution of the ground displacement caused by a shallow circular tunneling is derived.Non-symmetric deformation relative to the horizontal center line of the tun...Using the complex variable method,an elastic analytical solution of the ground displacement caused by a shallow circular tunneling is derived.Non-symmetric deformation relative to the horizontal center line of the tunnel cross-section is used as a boundary condition.A comparison between the proposed analytical method and the Finite Element Method is carried out to validate the rationality of the obtained analytical solution.Two parameters in the Peck formula,namely the maximum settlement of the ground surface center and the width coefficient of settlement curve,are fitted and determined.We propose a modified Peck formula by considering three input parameters,namely the tunnel depth,tunnel radius,and the tunnel gap.The influence of these three parameters on the modified Peck formula is analyzed.The applicability of the modified Peck formula is further investigated by reference to six engineering projects.The ground surface displacement obtained by the explicit Peck formula is in good agreement with the field data,and the maximum error is only 1.3 cm.The proposed formula can quickly and reasonably predict the ground surface settlement caused by tunnelling.展开更多
With the increasing researches on geotechnical properties of the diesel contaminated soil( DCS),the water content measured is indispensable part during the early period. In this study,the relative error of water conte...With the increasing researches on geotechnical properties of the diesel contaminated soil( DCS),the water content measured is indispensable part during the early period. In this study,the relative error of water content measurement using the traditional method is as high as 20. 78%,which is no longer suitable for contaminated soil. Through a series of tests to measure the loss coefficient of diesel in the drying time,the authors finally proposed a modified calculation formula for test samples. The results show that the maximum relative error calculated by using the modified formula is 0. 96%,far lower than that of traditional formula,which can provide accurate data for further study of diesel contaminated soil.展开更多
文摘Objective: To evaluate the accuracy of glomerular filtration rate formula by comparising the CKD-EPI 2009 formula and the modified Modified MDRD formula with the 99mTc-DTPA double-phase plasma method as "gold standard" respectively. Methods: Totally 166 patients diognosed as chronic kidney disease (CKD) were enrolled. The 99mTc-DTPA double-plasma method (rGFR) was used as the "gold standard". The CKD-EPI 2009 formula and the modified MDRD formula were used to calculate eGFR. Statistical software was used to analyze the correlation between the calculated values of the two formulas and the gold standard value and the bias. Then we evaluated the accuracy of the two GFR formulas. Results: Among the CKD stage 1 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (13.9911.45;20.1815.90);both formulas were weakly correlated with the gold standard (correlation coefficients were 0.216, 0.229, P<0.01, respectively);The probability that the bias of the calculated value of the CKD-EPI 2009 formula less than 15%, 30%, and 50% of the gold standard value is smaller. Among the CKD stage 2 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (12.748.45;15.6811.01);both formulas were moderately correlated with the gold standard (correlation coefficients were 0.568, 0.581, P<0.01, respectively);The probability that the bias of the calculated value of the CKD-EPI 2009 formula less than 15%, 30%, and 50% of the gold standard value is smaller. Among the CKD stage 3 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (12.6410.27;12.8810.97), and both formulas were strongly correlated with the gold standard (correlation coefficients were 0.664, 0.670, P<0.01, respectively);The probability that the bias of the calculated value of the Modified MDRD formula less than 15%, 30%, and 50% of the gold standard value is smaller. Among the CKD stage 4 to 5 patients, the bias of the CKD-EPI 2009 formula was smaller than that of the Modified MDRD formula (5.585.36;5.945.20);The CKD-EPI 2009 formula and the Modified MDRD formula were strongly correlated with the gold standard (correlation coefficient r was 0.808. 0.802, P<0.01, respectively);The probability of the bias of the calculated value of the CKD-EPI 2009 formula less than 15%, 30%, and 50% of the gold standard value is smaller. In patients with decreased renal function with GFR <60 ml/min, the sensitivity and positive predictive value of the CKD-EPI 2009 formula for the diagnosis of "decreased renal function"were higher, and the specificity was comparable. Conclusion: 1. When the renal function is only slightly decreased, the accuracy of the two formulas is not good. In this condition, the CKD-EPI 2009 formula is more accurate and recommended. 2. It is necessary to further improve the current formulas especialy when it comes to value the slightly declined renal function;3. When we try to identify the stage of CKD patients, only based on eGFR may cause misclassification, it is recommended to combine the cause-GFR-albuminuria staging to assess the stage of CKD;4. The current formulas have limitations.in the case that requires a highly accurate assessment of GFR, the 99mTc-DTPA dual plasma method is recommended.
文摘Objective To investigate the effect of modified Leweiyin Formula(MLF)on key glycolytic regulatory targets in the gastric mucosa of rats with chronic atrophic gastritis(CAG)based on the phosphatidylinositol 3-kinase(PI3K)/protein kinase B(AKT)/mammalian target of rapamycin(mTOR)signalingpathway.Methods The CAG rat model was induced using a combination of free drinking of 1-methyl-3-nitro-1-nitrosoguanidine(MNNG),oral administration of sodium salicylate,and an irregular feeding schedule.After modeling,except for the blank group,the remaining rats were randomly divided into the model group,Vitacoenzyme group,Chinese medicine(CM)low-dose group(6.3 g/kg),and CM high-dose group(25.2 g/kg),with 6 rats in each group.Rats in the normal group and the model group were gavaged daily with sterilized water.Each group received daily interventions for 28 days.HE staining was used to observe pathological changes of gastric mucosa.Alisin Blue-Periodic Acid Schiff(ABPAS)stainingwas used to detect the intestinal metaplasia.The changes of gastric mucosal epithelial cells were observe by Scanning electron microscopy(SEM).The mRNA expressions of glucose transporter 1(Glutl),hexokinase 2(HK2),pyruvate kinase M2(PKM2),and lactate dehydrogenase A(LDHA)were detected using qRT-PCR.The protein expressions of Glutl,HK2,PKM2,LDHA,PI3K,AKT,and mTOR were detected using Western Blot.Results Compared with the blank group,the model group showed decreased body weight(P<0.01),reduced food intake,lethargy,and pathological changes in the gastric mucosa,including atrophy and intestinal metaplasia.mRNA and protein expressions of Glutl,HK2,PKM2,and LDHA increased(P<0.05,P<0.01),the protein expressions of PI3K,AKT,and mTOR increased in the model group(P<0.01).Compared with the model group,the body weight of rats in all intervention groups increased(P<0.01),and their food intake,body weight,and mental state were all improved;the Vitacoenzyme group and the CM low-dose group,as well as the CM high-dose group,all repaired the gastric mucosal damage in CAG model rats from a pathological perspective and alleviated intestinal metaplasia.Compared with the model group,the levels of Glutl,HK2,and PKM2 mRNA reduced in all intervention groups(P<0.01),and the level of LDHA mRNA decreased in the CM high-dose group(P<0.01).Additionally,the protein expressions of PKM2,LDHA,Glutl,HK2,PI3K,and mTOR reduced in the CM low-dose and high-dose groups(P<0.05,P<0.01),AKT protein expressions decreased in the CM high-dose group(P<0.01).Conclusion MLF may treat chronic atrophic gastritis by down-regulating key glycolytic targets(Glutl,HK2,PKM2,and LDHA)through inhibition of the PI3K/AKT/mTOR pathway.
基金Ministry of Science and Technology of Chinaand the Earthquake Science Foundation of China Under GrandNo.102033
文摘An error analysis of the dynamic shear modulus of stiff specimens from tests performed by a new resonant column device developed by the Institute of Engineering Mechanics, China was conducted. A modified approach for calculating the dynamic shear modulus of the stiff specimens is presented. The error formula of the tests was deduced and parameters that impact the accuracy of the test were identified. Using six steel specimens with known standard stiffness as a base, a revised dynamic shear modulus calculation for stiff specimens was formulated by comparing three of the models. The maximum error between the test results and the calculated results shown by curves from both the free-vibration and the resonant-vibration tests is less than 6%. The free-vibration and resonant-vibration tests for three types of stiff samples with a known modulus indicate that the maximum deviation between the actual and the tested value using the modified approach were less than 10%. As a result, the modified approach presented here is shown to be reliable and the new device can be used for testing dynamic shear modulus of any stiff materials at low shear strain levels
基金Supported by the Natural Science Foundation of Hebei Province （Grant No. E2012201057） the Scientific and Technological Projects of Hebei Province （Grant No. 2009056） the Natural Science Foundation of Tianjin （Grant No. 10JCYBJC03700）
文摘The quarter-circular caisson breakwater （QCB） is a new type of breakwater, and it can be applied in deepwater. The stability of QCB under wave force action can be enhanced, and the rubble mound engineering can be less than that of semi-circular breakwaters in deepwater. In order to study the wave force distribution acting on the QCB, to find wave force formula for this type of breakwater, firstly in this paper, the distribution characteristics of the horizontal force, the downward vertical force and the uplift force on the breakwater were gotten based on physical model wave flume experiments and on the analysis of the wave pressure experimental data. Based on a series of physical model tests acted by irregular waves, a kind of calculation method, which was modified by Goda formula, was proposed to carry out the wave force on the QCB. Secondly, the reliability method with correlated variables was adopted to analyze the QCB, considering the high correlation between wave forces or moments. Utilizing the observed wave data in engineering field, the reliability index and failure probability of QCB were obtained. Finally, a factor Q=0.9 is given to modify the zero pressure height above SWL of QCB, and wave force partial coefficient 1.34 to the design expressions of QCB for anti-sliding, as well as 1.67 for anti-overturning, were presented.
文摘Several researchers have dealt with the one-dimensional fractional heat conduction equation in the last decades,but as far as we know,no one has investigated such a problem from the perspective of developing suitable fractional-order methods.This has actually motivated us to address this problem by the way of establishing a proper fractional approach that involves employing a combination of a novel fractional difference formula to approximate the Caputo differentiator of orderαcoupled with the modified three-point fractional formula to approximate the Caputo differentiator of order 2α,where 0<α≤1.As a result,the fractional heat conduction equation is then reexpressed numerically using the aforementioned formulas,and by dividing the considered mesh into multiple nodes,a system is generated and algebraically solved with the aid of MATLAB.This would allow us to obtain the desired approximate solution for the problem at hand.
基金National Natural Science Foundation of China(Grant Nos.52025084 and 52208396)China Postdoctoral Science Foundation(No.2021M701934).
文摘Using the complex variable method,an elastic analytical solution of the ground displacement caused by a shallow circular tunneling is derived.Non-symmetric deformation relative to the horizontal center line of the tunnel cross-section is used as a boundary condition.A comparison between the proposed analytical method and the Finite Element Method is carried out to validate the rationality of the obtained analytical solution.Two parameters in the Peck formula,namely the maximum settlement of the ground surface center and the width coefficient of settlement curve,are fitted and determined.We propose a modified Peck formula by considering three input parameters,namely the tunnel depth,tunnel radius,and the tunnel gap.The influence of these three parameters on the modified Peck formula is analyzed.The applicability of the modified Peck formula is further investigated by reference to six engineering projects.The ground surface displacement obtained by the explicit Peck formula is in good agreement with the field data,and the maximum error is only 1.3 cm.The proposed formula can quickly and reasonably predict the ground surface settlement caused by tunnelling.
文摘With the increasing researches on geotechnical properties of the diesel contaminated soil( DCS),the water content measured is indispensable part during the early period. In this study,the relative error of water content measurement using the traditional method is as high as 20. 78%,which is no longer suitable for contaminated soil. Through a series of tests to measure the loss coefficient of diesel in the drying time,the authors finally proposed a modified calculation formula for test samples. The results show that the maximum relative error calculated by using the modified formula is 0. 96%,far lower than that of traditional formula,which can provide accurate data for further study of diesel contaminated soil.
