In cerebrovascular interventional surgery,spatial position prediction navigation(SPPN)provides 3D spatial information of the vascular lumen,reducing the spatial dimension loss from digital subtraction angiography(DSA)...In cerebrovascular interventional surgery,spatial position prediction navigation(SPPN)provides 3D spatial information of the vascular lumen,reducing the spatial dimension loss from digital subtraction angiography(DSA)and improving surgical precision.However,it is limited in its adaptability to complex vascular environments and prone to error accumulation.To address these issues,we propose spatial position prediction-based multimodal navigation(SPPMN),integrating minimal intraoperative X-ray images to enhance SPPN accuracy.In the first phase,a feature-weighted dynamic time warping(FDTW)-based branch matching algorithm is introduced for 3D topological positioning under non-registered conditions,with a dynamic location repositioning module for real-time corrections.In the second phase,an occlusion correction module,based on the elastic potential energy of the instrument tip,dynamically adjusts the tip's angle to achieve low-projection occlusion control.Experimental validation using a high-precision electromagnetic tracking system(EMTS)on a 3D vascular model shows that the proposed method achieves an average 3D positioning accuracy of 9.36 mm in intracranial vascular regions,with a 78%reduction in radiation exposure,significantly enhancing both precision and safety in interventional surgeries.展开更多
Low cycle fatigue behavior of a quenched and tempered high-strength steel(Q960 E) was studied in the strain amplitude ranging from ± 0.5% to ± 1.2% at room temperature. As a result of fatigue loading, the di...Low cycle fatigue behavior of a quenched and tempered high-strength steel(Q960 E) was studied in the strain amplitude ranging from ± 0.5% to ± 1.2% at room temperature. As a result of fatigue loading, the dislocation structural evolution and fracture mechanism were examined and studied by transmission electron microscopy and scanning electron microscopy(SEM). The results showed that this Q960 E steel showed cyclic softening at different strain amplitudes, and the softening tendency was more apparent at strain amplitude of ±(0.6–1.2)% than that at ± 0.5%. The reduction in dislocation density with increasing strain amplitude is responsible for the softening tendency of cyclic stress with the strain amplitude. The material illustrates near-Masing behavior at strain amplitude ranging from ± 0.6% to ± 1.2%. The near-Masing behavior of Q960 E high-strength steel can be the result of stability of martensite lath at different strain amplitudes. Partial transformation from martensite laths to dislocation cells is responsible for the derivation from ideal Masing behavior. In the SEM examination of fracture surfaces, transgranular cracks initiate on the sample surface. Striations can be found during the crack propagation stage.展开更多
Balance solubility products and enthalpy of for- mation for NbC0.75, NbC0.85, NbC0.88, NbC and NbN in oriented silicon steels were calculated and compared quali- tatively. Meanwhile, the mixing enthalpies of these fiv...Balance solubility products and enthalpy of for- mation for NbC0.75, NbC0.85, NbC0.88, NbC and NbN in oriented silicon steels were calculated and compared quali- tatively. Meanwhile, the mixing enthalpies of these five Nb compounds were calculated based on Miedema Model. The results show that the solubility products of Nb compounds in ferrite and austenite meet the following relationship, NbC0.75 〉 NbC0.85 〉 NbC0.88 〉 NbC 〉 NbN and NbN has the minimum enthalpy of formation. It indicates that NbN easily precipitate out, but it is more difficult for NbC0.75.展开更多
AIM： To develop a pharmacodynamic model of porta hypertension from chronic hepatitis. METHODS： Pathological changes and collagen depositions were analyzed using morphometry to confirm CCI4-induced chronic hepatitis....AIM： To develop a pharmacodynamic model of porta hypertension from chronic hepatitis. METHODS： Pathological changes and collagen depositions were analyzed using morphometry to confirm CCI4-induced chronic hepatitis. At do, d28, ds6 and d84 of the process, the portal perfused velocities （μL/min） in isolated rat livers were exactly controlled with a quanti-fied pump. The pressure （mmHg） was monitored with a Physiological System. The geometric concentrations of phenylephrine or acetylcholine were added to a fixed volume （300 mL） of the circulating perfusate. The equation, the median effective concentration and its 95% confidence intervals of phenylephrine or acetyl- choline were regressed with Prism-4 software in non-linear fit and various slopes. In the isolated perfused rat livers with chronic hepatitis, both median effective concentrations were defined as the pharmacodynamic model of portal hypertension.CONCLUSION： A pharmacodynamic model of portal hypertension in isolated perfused rat livers with chronic hepatitis was defined as the median effective concen- trations of phenylephrine and acetylcholine.展开更多
基金supported in part by the National Key Research and Development Program of China(2024YFF1206902)in part by the National Natural Science Foundation of China(62303463)+1 种基金in part by the Beijing Natural Science Foundation,China(L232137,L246047)in part by the National High Level Hospital Clinical Research Funding(2022-PUMCH-B-125).
文摘In cerebrovascular interventional surgery,spatial position prediction navigation(SPPN)provides 3D spatial information of the vascular lumen,reducing the spatial dimension loss from digital subtraction angiography(DSA)and improving surgical precision.However,it is limited in its adaptability to complex vascular environments and prone to error accumulation.To address these issues,we propose spatial position prediction-based multimodal navigation(SPPMN),integrating minimal intraoperative X-ray images to enhance SPPN accuracy.In the first phase,a feature-weighted dynamic time warping(FDTW)-based branch matching algorithm is introduced for 3D topological positioning under non-registered conditions,with a dynamic location repositioning module for real-time corrections.In the second phase,an occlusion correction module,based on the elastic potential energy of the instrument tip,dynamically adjusts the tip's angle to achieve low-projection occlusion control.Experimental validation using a high-precision electromagnetic tracking system(EMTS)on a 3D vascular model shows that the proposed method achieves an average 3D positioning accuracy of 9.36 mm in intracranial vascular regions,with a 78%reduction in radiation exposure,significantly enhancing both precision and safety in interventional surgeries.
基金financial supports of the National Natural Science Foundation of China (No. 51674079)Anhui Provincial Natural Science Foundation (Nos. KJ2018A0062, KJ2017A128 and KJ2017A066)
文摘Low cycle fatigue behavior of a quenched and tempered high-strength steel(Q960 E) was studied in the strain amplitude ranging from ± 0.5% to ± 1.2% at room temperature. As a result of fatigue loading, the dislocation structural evolution and fracture mechanism were examined and studied by transmission electron microscopy and scanning electron microscopy(SEM). The results showed that this Q960 E steel showed cyclic softening at different strain amplitudes, and the softening tendency was more apparent at strain amplitude of ±(0.6–1.2)% than that at ± 0.5%. The reduction in dislocation density with increasing strain amplitude is responsible for the softening tendency of cyclic stress with the strain amplitude. The material illustrates near-Masing behavior at strain amplitude ranging from ± 0.6% to ± 1.2%. The near-Masing behavior of Q960 E high-strength steel can be the result of stability of martensite lath at different strain amplitudes. Partial transformation from martensite laths to dislocation cells is responsible for the derivation from ideal Masing behavior. In the SEM examination of fracture surfaces, transgranular cracks initiate on the sample surface. Striations can be found during the crack propagation stage.
基金financially supported by the National Natural Science Foundation of China (Nos. 51274083 and 51074062)
文摘Balance solubility products and enthalpy of for- mation for NbC0.75, NbC0.85, NbC0.88, NbC and NbN in oriented silicon steels were calculated and compared quali- tatively. Meanwhile, the mixing enthalpies of these five Nb compounds were calculated based on Miedema Model. The results show that the solubility products of Nb compounds in ferrite and austenite meet the following relationship, NbC0.75 〉 NbC0.85 〉 NbC0.88 〉 NbC 〉 NbN and NbN has the minimum enthalpy of formation. It indicates that NbN easily precipitate out, but it is more difficult for NbC0.75.
基金Supported by The Major State Creative New Drug Project,No.2009ZX09502-017Education Ministry Science Foundation ofChina,No. 108019
文摘AIM： To develop a pharmacodynamic model of porta hypertension from chronic hepatitis. METHODS： Pathological changes and collagen depositions were analyzed using morphometry to confirm CCI4-induced chronic hepatitis. At do, d28, ds6 and d84 of the process, the portal perfused velocities （μL/min） in isolated rat livers were exactly controlled with a quanti-fied pump. The pressure （mmHg） was monitored with a Physiological System. The geometric concentrations of phenylephrine or acetylcholine were added to a fixed volume （300 mL） of the circulating perfusate. The equation, the median effective concentration and its 95% confidence intervals of phenylephrine or acetyl- choline were regressed with Prism-4 software in non-linear fit and various slopes. In the isolated perfused rat livers with chronic hepatitis, both median effective concentrations were defined as the pharmacodynamic model of portal hypertension.CONCLUSION： A pharmacodynamic model of portal hypertension in isolated perfused rat livers with chronic hepatitis was defined as the median effective concen- trations of phenylephrine and acetylcholine.
