Objective To explore the value of ultrafast pulse wave velocity(UFPWV)technique for evaluating changes of carotid artery elasticity in Hashimoto thyroiditis(HT)patients with euthyroidism.Methods Conventional ultrasoun...Objective To explore the value of ultrafast pulse wave velocity(UFPWV)technique for evaluating changes of carotid artery elasticity in Hashimoto thyroiditis(HT)patients with euthyroidism.Methods Conventional ultrasound and UFPWV for carotid artery were prospectively performed in 91 HT patients with euthyroidism(HT group)and 81 healthy subjects(control group).Clinical data and ultrasonic parameters were compared between groups.Spearman correlation analysis was performed to observe the correlations of carotid pulse wave velocity in end of systole(PWV-ES)with clinical indexes and other ultrasonic parameters in HT group.Multiple stepwise linear regression analysis was used to screen the independent impact factors of increased carotid PWV-ES in HT group.Results Significant differences of thyroid peroxidase antibody(TPOAb),thyroglobulin antibody(TgAb),total cholesterol(TC),low density lipoprotein and neutrophil-lymphocyte ratio(NLR)were found between groups(all P<0.05).The carotid PWV-ES in HT group was significantly higher than that in control group(P<0.05),while no significant difference of carotid artery intima-media thickness(CIMT)nor carotid pulse wave velocity in beginning of systole(PWV-BS)was found between groups(both P>0.05).Carotid PWV-ES in HT group was positively correlated with patients'age,body mass index,TPOAb,TC,triglyceride,NLR and CIMT(r=0.217—0.707,all P<0.05).Patients'age,TPOAb and NLR were all independent impact factors of increased carotid PWV-ES in HT patients with euthyroidism(all P<0.05).Conclusion UFPWV technique could be used to evaluate changes of carotid artery elasticity in HT patients with euthyroidism,among which PWV-ES was relatively sensitive.展开更多
Objective To explore prenatal ultrasonic characteristics of fetal Currarino syndrome(CS)and methods for prenatal diagnosis of CS.Methods Two fetuses with CS confirmed by genetic examination were retrospectively analyz...Objective To explore prenatal ultrasonic characteristics of fetal Currarino syndrome(CS)and methods for prenatal diagnosis of CS.Methods Two fetuses with CS confirmed by genetic examination were retrospectively analyzed,while 6 CS fetuses with complete prenatal ultrasonic data in literature were reviewed.Prenatal ultrasonic characteristics of CS fetuses and the method for prenatal diagnosis of CS were discussed.Results Among 8 CS fetuses diagnosed with prenatal ultrasound,4 were female singletons with a clear family history of CS,and MNX 1 gene mutation was found in 1 fetus.The other 4 fetuses were 2 pairs of male monochorionic twins,all with MNX 1 gene mutation.Among 8 CS fetuses,complete triad(sacral agenesis abnormalities,anorectal malformation and presacral mass)were displayed only in 2 fetuses,while all 8 had sacral agenesis abnormalities and 6(6/8,75.00%)were detected with prenatal ultrasound,6 had low location of conus medullaris and 2(2/6,33.33%)detected with prenatal ultrasound.Conclusion Prenatal ultrasound was the first choice for non-invasive diagnosis of fetal CS.When one of sacral agenesis abnormalities,anorectal malformation and presacral mass was found with prenatal ultrasound,the possibility of CS should be considered,and fetal MRI,genetic examination and prenatal genetic counselling should be recommended if necessary.展开更多
Objective To observe the values of changes of right heart modified myocardial performance index(Mod-MPI)and ductus venosus(DV)spectrum parameters in pre-eclampsia fetuses for predicting adverse pregnancy outcomes.Meth...Objective To observe the values of changes of right heart modified myocardial performance index(Mod-MPI)and ductus venosus(DV)spectrum parameters in pre-eclampsia fetuses for predicting adverse pregnancy outcomes.Methods Eighty-one pregnant women diagnosed as pre-eclampsia were prospectively enrolled and divided into severe pre-eclampsia(SPE)group(n=39)and mild pre-eclampsia(MPE)group(n=42),while 85 healthy pregnant women were taken as controls(control group).Fetal right heart function parameters,including right ventricular isovolumetric relaxation time(IRT),isovolumetric contraction time(ICT),ejection time(ET),total spent time(TST),Mod-MPI,tricuspid valve peak flow velocity ratio in early and late diastole(TV-E/A),as well as blood flow velocities in each waveform of DV spectrum(S,V,D,and A wave)were obtained,and the pulsatility index(PI)and the ratio of blood flow velocities in each waveform of the DV(S/V,S/D,S/A,V/D,V/A,D/A)were calculated.Intrauterine fetal distress,preterm delivery,neonatal asphyxia and newborn with low weight were considered as adverse pregnancy outcomes.The correlations of right heart Mod-MPI and TV-E/A with DV parameters in pre-eclampsia fetuses were assessed,and their predictive efficacies for adverse pregnancy outcomes were evaluated for right heart Mod-MPI and DV using the receiver operating characteristics(ROC)and the area under the curves(AUC).Results Compared with control group and MPE group,fetal right heart IRT,ICT and Mod-MPI increased and ET decreased in SPE group(all P<0.05).No significant differences of right heart TST and TV-E/A among 3 groups(both P>0.05).Fetal DV A-wave velocity and V/D values progressively decreased but PI progressively increased in control,MPE and SPE groups(all P<0.05).Fetal right heart Mod-MPI in pre-eclampsia was moderately positively correlated with DV PI(r=0.637,P=0.016),while TV-E/A was weakly negatively correlated with DV V/D(r=-0.355,P=0.043).Adverse pregnancy outcomes were noticed in 59 pre-eclampsia cases.The AUC of fetal right heart Mod-MPI and DV PI for predicting adverse pregnancy outcomes in pre-eclampsia cases was 0.897 and 0.848,respectively,without significant difference(Z=0.460,P=0.400).Conclusion Changes of right heart Mod-MPI and DV spectrum parameters in pre-eclampsia fetuses had high value for predicting adverse pregnancy outcomes.展开更多
In this study,the morphology and ultrastructure of the compound eye of L.lewisii were investigated using scanning electron microscopy(SEM),transmission electron microscopy(TEM),microcomputed tomography(μCT),and 3D re...In this study,the morphology and ultrastructure of the compound eye of L.lewisii were investigated using scanning electron microscopy(SEM),transmission electron microscopy(TEM),microcomputed tomography(μCT),and 3D reconstruction.The compound eye of L.lewisii was of the apposition type,with an average of 121.88±7.64 ommatidia in males and 119.00±4.71 ommatidia in females.Each ommatidium was composed of a biconvex cornea,an acone consisting of four cone cells,eight retinular cells along with the rhabdom,two primary pigment cells,and numerous secondary pigment cells.The open type of rhabdom in L.lewisii consists of six peripheral rhabdomeres contributed by the six peripheral retinular cells(R1~R6)and two vertically attached central rhabdomeres contributed by R7 and R8 respectively.The orientation of microvilli suggested a weak sensitivity to polarized light perception.展开更多
To keep the tunnel face stable is very important for tunnel construction.In this paper,the tunnel face stability under the advanced pipe was analyzed using the Winkler foundation model and rigid limit equilibrium.The ...To keep the tunnel face stable is very important for tunnel construction.In this paper,the tunnel face stability under the advanced pipe was analyzed using the Winkler foundation model and rigid limit equilibrium.The tunnel face deformation characteristics were also analyzed using the numerical simulation.The influence of parameters on the deflection of the pipe roof and the stability of the tunnel face were discussed.The results show that the tunnel face stability can be improved through increasing the pipe diameter,decreasing the initial displacement at the beginning of the pipe seat,and adopting the short round length and small excavation height.With the increase of tunnel burial depth,the safety factor of tunnel face stability first decreases,then increases,and then remains unchanged.The deformation at the center of the tunnel face is larger than the deformation at the surround sides and at the corner.The horizontal displacement varies little with the increasing of the pipe length.The horizontal displacement at the center of the tunnel face increases with the increase of the pipe ring spacing and the pipe longitudinal spacing.There is an optimum external angle.展开更多
Due to global energy depletion,solar energy technology has been widely used in the world.The output power of the solar energy systems is affected by solar radiation.Accurate short-term forecasting of solar radiation c...Due to global energy depletion,solar energy technology has been widely used in the world.The output power of the solar energy systems is affected by solar radiation.Accurate short-term forecasting of solar radiation can ensure the safety of photovoltaic grids and improve the utilization efficiency of the solar energy systems.In the study,a new decomposition-boosting model using artificial intelligence is proposed to realize the solar radiation multi-step prediction.The proposed model includes four parts:signal decomposition(EWT),neural network(NARX),Adaboost and ARIMA.Three real solar radiation datasets from Changde,China were used to validate the efficiency of the proposed model.To verify the robustness of the multi-step prediction model,this experiment compared nine models and made 1,3,and 5 steps ahead predictions for the time series.It is verified that the proposed model has the best performance among all models.展开更多
The Jianpudong No. 4 tunnel is a shallow tunnel, which belongs to Shaoshan County scenic highway in Hunan province, China and whose surrounding rock is weak. According to its characteristics, the field monitoring test...The Jianpudong No. 4 tunnel is a shallow tunnel, which belongs to Shaoshan County scenic highway in Hunan province, China and whose surrounding rock is weak. According to its characteristics, the field monitoring tests and numerical analysis were done. The mechanical characteristics of shallow tunnels under weak surrounding rock and the stress-strain rule of surrounding rock and support were analyzed. The numerical analysis results show that the settlement caused by upper bench excavating accounts for 44% of the total settlement, and the settlement caused by tunnel upper bench supporting accounts for 56% of the total settlement. The maximum axial force of shotcrete lining is 177.2 k N, which locates in hance under the secondary lining. The maximum moment of shotcrete lining is 5.08 k N·m, which locates in the arch foot. The stress curve of steel arch has three obvious stages during the tunnel construction. The maximum axial force of steel arch is 297.4 k N, which locates in tunnel vault. The axial forces of steel arch are respectively 23.5 k N and-21.8 k N, which is influenced by eccentric compression of shallow tunnel and locates in hance. The results show that there is larger earth pressure in tunnel vault which is most unfavorable position of steel arch. Therefore, the advance support should be strengthened in tunnel vault during construction process.展开更多
文摘Objective To explore the value of ultrafast pulse wave velocity(UFPWV)technique for evaluating changes of carotid artery elasticity in Hashimoto thyroiditis(HT)patients with euthyroidism.Methods Conventional ultrasound and UFPWV for carotid artery were prospectively performed in 91 HT patients with euthyroidism(HT group)and 81 healthy subjects(control group).Clinical data and ultrasonic parameters were compared between groups.Spearman correlation analysis was performed to observe the correlations of carotid pulse wave velocity in end of systole(PWV-ES)with clinical indexes and other ultrasonic parameters in HT group.Multiple stepwise linear regression analysis was used to screen the independent impact factors of increased carotid PWV-ES in HT group.Results Significant differences of thyroid peroxidase antibody(TPOAb),thyroglobulin antibody(TgAb),total cholesterol(TC),low density lipoprotein and neutrophil-lymphocyte ratio(NLR)were found between groups(all P<0.05).The carotid PWV-ES in HT group was significantly higher than that in control group(P<0.05),while no significant difference of carotid artery intima-media thickness(CIMT)nor carotid pulse wave velocity in beginning of systole(PWV-BS)was found between groups(both P>0.05).Carotid PWV-ES in HT group was positively correlated with patients'age,body mass index,TPOAb,TC,triglyceride,NLR and CIMT(r=0.217—0.707,all P<0.05).Patients'age,TPOAb and NLR were all independent impact factors of increased carotid PWV-ES in HT patients with euthyroidism(all P<0.05).Conclusion UFPWV technique could be used to evaluate changes of carotid artery elasticity in HT patients with euthyroidism,among which PWV-ES was relatively sensitive.
文摘Objective To explore prenatal ultrasonic characteristics of fetal Currarino syndrome(CS)and methods for prenatal diagnosis of CS.Methods Two fetuses with CS confirmed by genetic examination were retrospectively analyzed,while 6 CS fetuses with complete prenatal ultrasonic data in literature were reviewed.Prenatal ultrasonic characteristics of CS fetuses and the method for prenatal diagnosis of CS were discussed.Results Among 8 CS fetuses diagnosed with prenatal ultrasound,4 were female singletons with a clear family history of CS,and MNX 1 gene mutation was found in 1 fetus.The other 4 fetuses were 2 pairs of male monochorionic twins,all with MNX 1 gene mutation.Among 8 CS fetuses,complete triad(sacral agenesis abnormalities,anorectal malformation and presacral mass)were displayed only in 2 fetuses,while all 8 had sacral agenesis abnormalities and 6(6/8,75.00%)were detected with prenatal ultrasound,6 had low location of conus medullaris and 2(2/6,33.33%)detected with prenatal ultrasound.Conclusion Prenatal ultrasound was the first choice for non-invasive diagnosis of fetal CS.When one of sacral agenesis abnormalities,anorectal malformation and presacral mass was found with prenatal ultrasound,the possibility of CS should be considered,and fetal MRI,genetic examination and prenatal genetic counselling should be recommended if necessary.
文摘Objective To observe the values of changes of right heart modified myocardial performance index(Mod-MPI)and ductus venosus(DV)spectrum parameters in pre-eclampsia fetuses for predicting adverse pregnancy outcomes.Methods Eighty-one pregnant women diagnosed as pre-eclampsia were prospectively enrolled and divided into severe pre-eclampsia(SPE)group(n=39)and mild pre-eclampsia(MPE)group(n=42),while 85 healthy pregnant women were taken as controls(control group).Fetal right heart function parameters,including right ventricular isovolumetric relaxation time(IRT),isovolumetric contraction time(ICT),ejection time(ET),total spent time(TST),Mod-MPI,tricuspid valve peak flow velocity ratio in early and late diastole(TV-E/A),as well as blood flow velocities in each waveform of DV spectrum(S,V,D,and A wave)were obtained,and the pulsatility index(PI)and the ratio of blood flow velocities in each waveform of the DV(S/V,S/D,S/A,V/D,V/A,D/A)were calculated.Intrauterine fetal distress,preterm delivery,neonatal asphyxia and newborn with low weight were considered as adverse pregnancy outcomes.The correlations of right heart Mod-MPI and TV-E/A with DV parameters in pre-eclampsia fetuses were assessed,and their predictive efficacies for adverse pregnancy outcomes were evaluated for right heart Mod-MPI and DV using the receiver operating characteristics(ROC)and the area under the curves(AUC).Results Compared with control group and MPE group,fetal right heart IRT,ICT and Mod-MPI increased and ET decreased in SPE group(all P<0.05).No significant differences of right heart TST and TV-E/A among 3 groups(both P>0.05).Fetal DV A-wave velocity and V/D values progressively decreased but PI progressively increased in control,MPE and SPE groups(all P<0.05).Fetal right heart Mod-MPI in pre-eclampsia was moderately positively correlated with DV PI(r=0.637,P=0.016),while TV-E/A was weakly negatively correlated with DV V/D(r=-0.355,P=0.043).Adverse pregnancy outcomes were noticed in 59 pre-eclampsia cases.The AUC of fetal right heart Mod-MPI and DV PI for predicting adverse pregnancy outcomes in pre-eclampsia cases was 0.897 and 0.848,respectively,without significant difference(Z=0.460,P=0.400).Conclusion Changes of right heart Mod-MPI and DV spectrum parameters in pre-eclampsia fetuses had high value for predicting adverse pregnancy outcomes.
文摘In this study,the morphology and ultrastructure of the compound eye of L.lewisii were investigated using scanning electron microscopy(SEM),transmission electron microscopy(TEM),microcomputed tomography(μCT),and 3D reconstruction.The compound eye of L.lewisii was of the apposition type,with an average of 121.88±7.64 ommatidia in males and 119.00±4.71 ommatidia in females.Each ommatidium was composed of a biconvex cornea,an acone consisting of four cone cells,eight retinular cells along with the rhabdom,two primary pigment cells,and numerous secondary pigment cells.The open type of rhabdom in L.lewisii consists of six peripheral rhabdomeres contributed by the six peripheral retinular cells(R1~R6)and two vertically attached central rhabdomeres contributed by R7 and R8 respectively.The orientation of microvilli suggested a weak sensitivity to polarized light perception.
基金Project(20A187)supported by the Hunan Provincial Department of Education,ChinaProjects(51408216,51308209)supported by the National Natural Science Foundation of China。
文摘To keep the tunnel face stable is very important for tunnel construction.In this paper,the tunnel face stability under the advanced pipe was analyzed using the Winkler foundation model and rigid limit equilibrium.The tunnel face deformation characteristics were also analyzed using the numerical simulation.The influence of parameters on the deflection of the pipe roof and the stability of the tunnel face were discussed.The results show that the tunnel face stability can be improved through increasing the pipe diameter,decreasing the initial displacement at the beginning of the pipe seat,and adopting the short round length and small excavation height.With the increase of tunnel burial depth,the safety factor of tunnel face stability first decreases,then increases,and then remains unchanged.The deformation at the center of the tunnel face is larger than the deformation at the surround sides and at the corner.The horizontal displacement varies little with the increasing of the pipe length.The horizontal displacement at the center of the tunnel face increases with the increase of the pipe ring spacing and the pipe longitudinal spacing.There is an optimum external angle.
基金Project(2020TJ-Q06)supported by Hunan Provincial Science&Technology Talent Support,ChinaProject(KQ1707017)supported by the Changsha Science&Technology,ChinaProject(2019CX005)supported by the Innovation Driven Project of the Central South University,China。
文摘Due to global energy depletion,solar energy technology has been widely used in the world.The output power of the solar energy systems is affected by solar radiation.Accurate short-term forecasting of solar radiation can ensure the safety of photovoltaic grids and improve the utilization efficiency of the solar energy systems.In the study,a new decomposition-boosting model using artificial intelligence is proposed to realize the solar radiation multi-step prediction.The proposed model includes four parts:signal decomposition(EWT),neural network(NARX),Adaboost and ARIMA.Three real solar radiation datasets from Changde,China were used to validate the efficiency of the proposed model.To verify the robustness of the multi-step prediction model,this experiment compared nine models and made 1,3,and 5 steps ahead predictions for the time series.It is verified that the proposed model has the best performance among all models.
基金Projects(51408060,51208063)supported by the National Natural Science Foundation of China
文摘The Jianpudong No. 4 tunnel is a shallow tunnel, which belongs to Shaoshan County scenic highway in Hunan province, China and whose surrounding rock is weak. According to its characteristics, the field monitoring tests and numerical analysis were done. The mechanical characteristics of shallow tunnels under weak surrounding rock and the stress-strain rule of surrounding rock and support were analyzed. The numerical analysis results show that the settlement caused by upper bench excavating accounts for 44% of the total settlement, and the settlement caused by tunnel upper bench supporting accounts for 56% of the total settlement. The maximum axial force of shotcrete lining is 177.2 k N, which locates in hance under the secondary lining. The maximum moment of shotcrete lining is 5.08 k N·m, which locates in the arch foot. The stress curve of steel arch has three obvious stages during the tunnel construction. The maximum axial force of steel arch is 297.4 k N, which locates in tunnel vault. The axial forces of steel arch are respectively 23.5 k N and-21.8 k N, which is influenced by eccentric compression of shallow tunnel and locates in hance. The results show that there is larger earth pressure in tunnel vault which is most unfavorable position of steel arch. Therefore, the advance support should be strengthened in tunnel vault during construction process.
