Objective: To examine factors to predict the optimal stent pusher position when inserting ureteral stents under fluoroscopy.Methods: We retrospectively reviewed 327 patients who underwent ureteral stent insertion. We ...Objective: To examine factors to predict the optimal stent pusher position when inserting ureteral stents under fluoroscopy.Methods: We retrospectively reviewed 327 patients who underwent ureteral stent insertion. We considered the pubic bone as a useful anatomical landmark to insert ureteral stents under fluoroscopic guidance. Thus, we categorized patients into three groups (proximal, middle, and distal groups) according to the position of the radiopaque tip of the push catheter when inserting the ureteral stent. Success was defined as a completely curled ureteral stent tail. We compared stent insertion success rates among the three groups. A multivariate analysis was performed to identify the factors affecting stent insertion success.Results: In men, 36 (63.2%) cases were deemed successful in the proximal group compared with 40 (80.0%) cases in the middle group and 12 (20.7%) cases in the distal group (p<0.001). In women, 26 (45.6%) cases were deemed successful in the proximal group compared with 54 (98.2%) cases in the middle group and 38 (76.0%) cases in the distal group (p<0.001). With the multivariate analysis, the stent pusher position was the most significant factor influencing successful stent insertion (men: odds ratio 6.00, 95% confidence interval 2.66-13.51, p<0.001;women: odds ratio 37.80, 95% confidence interval 4.94-289.22, p<0.001).Conclusion: The position of the stent pusher affects stent insertion success. The middle of the pubic symphysis is the optimal position for the radiopaque tip of the pusher when inserting ureteral stents under fluoroscopic guidance.展开更多
Purpose – Straightness measurement of rail weld joint is of essential importance to railway maintenance. Dueto the lack of efficient measurement equipment, there has been limited in-depth research on rail weld joint ...Purpose – Straightness measurement of rail weld joint is of essential importance to railway maintenance. Dueto the lack of efficient measurement equipment, there has been limited in-depth research on rail weld joint with a5-m wavelength range, leaving a significant knowledge gap in this field.Design/methodology/approach – In this study, the authors used the well-established inertial referencemethod (IR-method), and the state-of-the-art multi-point chord reference method (MCR-method). Two methodshave been applied in different types of rail straightness measurement trollies, respectively. These instrumentswere tested in a high-speed rail section within a certain region of China. The test results were ultimatelyvalidated through using traditional straightedge and feeler gauge methods as reference data to evaluate the railweld joint straightness within the 5-m wavelength range.Findings – The research reveals that IR-method and MCR-method produce reasonably similar measurementresults for wavelengths below 1 m. However, MCR-method outperforms IR-method in terms of accuracy forwavelengths exceeding 3 m. Furthermore, it was observed that IR-method, while operating at a slower speed,carries the risk of derailing and is incapable of detecting rail weld joints and low joints within the track.Originality/value – The research compare two methods’ measurement effects in a longer wavelength rangeand demonstrate the superiority of MCR-method.展开更多
Corona discharge, as a common means to obtain non-equilibrium plasma, can generally obtain high-concentration plasma by increasing discharge points to meet production needs. However,the existing numerical simulation m...Corona discharge, as a common means to obtain non-equilibrium plasma, can generally obtain high-concentration plasma by increasing discharge points to meet production needs. However,the existing numerical simulation models used to study multi-point corona discharge are all calculations of small-scale space models, which cannot obtain the distribution characteristics of plasma in large space. Based on our previous research, this paper proposes a hybrid model for studying the distribution of multi-point discharge plasma in large-scale spaces, which divides the computational domain and computes separately with the hydrodynamic model and the ion mobility model. The simulation results are verified by a needle–ball electrode device. Firstly, the electric field distribution and plasma distribution of the needle electrodes with single tip and double tips are compared and discussed. Secondly, the plasma distribution of the needle electrode with the double tip at different voltages is investigated. Both computational and experimental results indicate that the charged particle concentration and current of the needle electrode with double tips are both twice as high as those of the needle electrode with a single tip. This model can extend the computational area of the multi-point corona discharge finite element model to the sub-meter(25 cm) or meter level, which provides an effective means to study the plasma distribution generated by multiple discharge points in large-scale space.展开更多
Laser tracers are a three-dimensional coordinate measurement system that are widely used in industrial measurement.We propose a geometric error identification method based on multi-station synchronization laser tracer...Laser tracers are a three-dimensional coordinate measurement system that are widely used in industrial measurement.We propose a geometric error identification method based on multi-station synchronization laser tracers to enable the rapid and high-precision measurement of geometric errors for gantry-type computer numerical control(CNC)machine tools.This method also improves on the existing measurement efficiency issues in the single-base station measurement method and multi-base station time-sharing measurement method.We consider a three-axis gantry-type CNC machine tool,and the geometric error mathematical model is derived and established based on the combination of screw theory and a topological analysis of the machine kinematic chain.The four-station laser tracers position and measurement points are realized based on the multi-point positioning principle.A self-calibration algorithm is proposed for the coordinate calibration process of a laser tracer using the Levenberg-Marquardt nonlinear least squares method,and the geometric error is solved using Taylor’s first-order linearization iteration.The experimental results show that the geometric error calculated based on this modeling method is comparable to the results from the Etalon laser tracer.For a volume of 800 mm×1000 mm×350 mm,the maximum differences of the linear,angular,and spatial position errors were 2.0μm,2.7μrad,and 12.0μm,respectively,which verifies the accuracy of the proposed algorithm.This research proposes a modeling method for the precise measurement of errors in machine tools,and the applied nature of this study also makes it relevant both to researchers and those in the industrial sector.展开更多
BACKGROUND According to the World Health Organization analgesic ladder,cancer-related pain generally begins with pharmacotherapy in a stepwise approach.Nevertheless,some patients continue to experience poorly controll...BACKGROUND According to the World Health Organization analgesic ladder,cancer-related pain generally begins with pharmacotherapy in a stepwise approach.Nevertheless,some patients continue to experience poorly controlled pain despite medications,particularly when considering adverse effects and self-care quality.Percutaneous cervical cordotomy is an alternative interventional procedure for unremitting unilateral intractable cancer-related pain.CASE SUMMARY The patient was diagnosed with lung cancer with destruction of the brachial plexus and ribs.For 2 mo,the patient experienced progressive severe weakness and pain in the right upper extremity.Notably,the pain intensity reached an extreme level,particularly when lying supine,even under heavy sedation.This heightened pain response posed a significant challenge;as a result,the patient was unable to undergo further evaluation through magnetic resonance imaging.Ultimately,he underwent percutaneous cervical cordotomy for symptom relief,resulting in complete resolution of right arm pain.After a 3-mo follow-up,the pain did not recur,and only a flurbiprofen local patch was required for mild scapular tightness.CONCLUSION Cordotomy,under careful patient selection,appears to enhance the quality of life of patients with unilateral cancerrelated pain.展开更多
BACKGROUND Prostatic artery embolization(PAE)is a promising but also technically demanding interventional radiologic treatment for symptomatic benign prostatic hyperplasia.Many technical challenges in PAE are associat...BACKGROUND Prostatic artery embolization(PAE)is a promising but also technically demanding interventional radiologic treatment for symptomatic benign prostatic hyperplasia.Many technical challenges in PAE are associated with the complex anatomy of prostatic arteries(PAs)and with the systematic attempts to catheterize the PAs of both pelvic sides.Long procedure times and high radiation doses are often the result of these attempts and are considered significant disadvantages of PAE.The authors hypothesized that,in selected patients,these disadvantages could be mitigated by intentionally embolizing PAs of only one pelvic side.AIM To describe the authors’approach for intentionally unilateral PAE(IU-PAE)and its potential benefits.METHODS This was a single-center retrospective study of patients treated with IU-PAE during a period of 2 years.IU-PAE was applied in patients with opacification of more than half of the contralateral prostatic lobe after angiography of the ipsilateral PA(subgroup A),or with markedly asymmetric prostatic enlargement,with the dominant prostatic lobe occupying at least two thirds of the entire gland(subgroup B).All patients treated with IU-PAE also fulfilled at least one of the following criteria:Severe tortuosity or severe atheromatosis of the pelvic arteries,non-visualization,or visualization of a tiny(<1 mm)contralateral PA on preprocedural computed tomographic angiography.Intraprocedural contrast-enhanced ultrasonography(iCEUS)was applied to monitor prostatic infarction.IU-PAE patients were compared to a control group treated with bilateral PAE.RESULTS IU-PAE was performed in a total 13 patients(subgroup A,n=7;subgroup B,n=6).Dose-area product,fluoroscopy time and operation time in the IU-PAE group(9767.8μGy∙m^(2),30.3 minutes,64.0 minutes,respectively)were significantly shorter(45.4%,35.9%,45.8%respectively,P<0.01)compared to the control group.Clinical and imaging outcomes did not differ significantly between the IU-PAE group and the control group.In the 2 clinical failures of IU-PAE(both in subgroup A),the extent of prostatic infarction(demonstrated by iCEUS)was significantly smaller compared to the rest of the IU-PAE group.CONCLUSION In selected patients,IU-PAE is associated with comparable outcomes,but with lower radiation exposure and a shorter procedure compared to bilateral PAE.iCEUS could facilitate patient selection for IU-PAE.展开更多
文摘Objective: To examine factors to predict the optimal stent pusher position when inserting ureteral stents under fluoroscopy.Methods: We retrospectively reviewed 327 patients who underwent ureteral stent insertion. We considered the pubic bone as a useful anatomical landmark to insert ureteral stents under fluoroscopic guidance. Thus, we categorized patients into three groups (proximal, middle, and distal groups) according to the position of the radiopaque tip of the push catheter when inserting the ureteral stent. Success was defined as a completely curled ureteral stent tail. We compared stent insertion success rates among the three groups. A multivariate analysis was performed to identify the factors affecting stent insertion success.Results: In men, 36 (63.2%) cases were deemed successful in the proximal group compared with 40 (80.0%) cases in the middle group and 12 (20.7%) cases in the distal group (p<0.001). In women, 26 (45.6%) cases were deemed successful in the proximal group compared with 54 (98.2%) cases in the middle group and 38 (76.0%) cases in the distal group (p<0.001). With the multivariate analysis, the stent pusher position was the most significant factor influencing successful stent insertion (men: odds ratio 6.00, 95% confidence interval 2.66-13.51, p<0.001;women: odds ratio 37.80, 95% confidence interval 4.94-289.22, p<0.001).Conclusion: The position of the stent pusher affects stent insertion success. The middle of the pubic symphysis is the optimal position for the radiopaque tip of the pusher when inserting ureteral stents under fluoroscopic guidance.
文摘Purpose – Straightness measurement of rail weld joint is of essential importance to railway maintenance. Dueto the lack of efficient measurement equipment, there has been limited in-depth research on rail weld joint with a5-m wavelength range, leaving a significant knowledge gap in this field.Design/methodology/approach – In this study, the authors used the well-established inertial referencemethod (IR-method), and the state-of-the-art multi-point chord reference method (MCR-method). Two methodshave been applied in different types of rail straightness measurement trollies, respectively. These instrumentswere tested in a high-speed rail section within a certain region of China. The test results were ultimatelyvalidated through using traditional straightedge and feeler gauge methods as reference data to evaluate the railweld joint straightness within the 5-m wavelength range.Findings – The research reveals that IR-method and MCR-method produce reasonably similar measurementresults for wavelengths below 1 m. However, MCR-method outperforms IR-method in terms of accuracy forwavelengths exceeding 3 m. Furthermore, it was observed that IR-method, while operating at a slower speed,carries the risk of derailing and is incapable of detecting rail weld joints and low joints within the track.Originality/value – The research compare two methods’ measurement effects in a longer wavelength rangeand demonstrate the superiority of MCR-method.
基金supported by National Natural Science Foundation of China (Nos.52207158 and 51821005)the Fundamental Research Funds for the Central Universities (HUST: No.2022JYCXJJ012)the National Key Research and Development Program of China (Nos.2016YFC0401002 and 2016YFC0401006)。
文摘Corona discharge, as a common means to obtain non-equilibrium plasma, can generally obtain high-concentration plasma by increasing discharge points to meet production needs. However,the existing numerical simulation models used to study multi-point corona discharge are all calculations of small-scale space models, which cannot obtain the distribution characteristics of plasma in large space. Based on our previous research, this paper proposes a hybrid model for studying the distribution of multi-point discharge plasma in large-scale spaces, which divides the computational domain and computes separately with the hydrodynamic model and the ion mobility model. The simulation results are verified by a needle–ball electrode device. Firstly, the electric field distribution and plasma distribution of the needle electrodes with single tip and double tips are compared and discussed. Secondly, the plasma distribution of the needle electrode with the double tip at different voltages is investigated. Both computational and experimental results indicate that the charged particle concentration and current of the needle electrode with double tips are both twice as high as those of the needle electrode with a single tip. This model can extend the computational area of the multi-point corona discharge finite element model to the sub-meter(25 cm) or meter level, which provides an effective means to study the plasma distribution generated by multiple discharge points in large-scale space.
基金Supported by Natural Science Foundation of Shaanxi Province of China(Grant No.2021JM010)Suzhou Municipal Natural Science Foundation of China(Grant Nos.SYG202018,SYG202134).
文摘Laser tracers are a three-dimensional coordinate measurement system that are widely used in industrial measurement.We propose a geometric error identification method based on multi-station synchronization laser tracers to enable the rapid and high-precision measurement of geometric errors for gantry-type computer numerical control(CNC)machine tools.This method also improves on the existing measurement efficiency issues in the single-base station measurement method and multi-base station time-sharing measurement method.We consider a three-axis gantry-type CNC machine tool,and the geometric error mathematical model is derived and established based on the combination of screw theory and a topological analysis of the machine kinematic chain.The four-station laser tracers position and measurement points are realized based on the multi-point positioning principle.A self-calibration algorithm is proposed for the coordinate calibration process of a laser tracer using the Levenberg-Marquardt nonlinear least squares method,and the geometric error is solved using Taylor’s first-order linearization iteration.The experimental results show that the geometric error calculated based on this modeling method is comparable to the results from the Etalon laser tracer.For a volume of 800 mm×1000 mm×350 mm,the maximum differences of the linear,angular,and spatial position errors were 2.0μm,2.7μrad,and 12.0μm,respectively,which verifies the accuracy of the proposed algorithm.This research proposes a modeling method for the precise measurement of errors in machine tools,and the applied nature of this study also makes it relevant both to researchers and those in the industrial sector.
文摘BACKGROUND According to the World Health Organization analgesic ladder,cancer-related pain generally begins with pharmacotherapy in a stepwise approach.Nevertheless,some patients continue to experience poorly controlled pain despite medications,particularly when considering adverse effects and self-care quality.Percutaneous cervical cordotomy is an alternative interventional procedure for unremitting unilateral intractable cancer-related pain.CASE SUMMARY The patient was diagnosed with lung cancer with destruction of the brachial plexus and ribs.For 2 mo,the patient experienced progressive severe weakness and pain in the right upper extremity.Notably,the pain intensity reached an extreme level,particularly when lying supine,even under heavy sedation.This heightened pain response posed a significant challenge;as a result,the patient was unable to undergo further evaluation through magnetic resonance imaging.Ultimately,he underwent percutaneous cervical cordotomy for symptom relief,resulting in complete resolution of right arm pain.After a 3-mo follow-up,the pain did not recur,and only a flurbiprofen local patch was required for mild scapular tightness.CONCLUSION Cordotomy,under careful patient selection,appears to enhance the quality of life of patients with unilateral cancerrelated pain.
基金the General Hospital“Tzanio”Institutional Review Board(Approval No.15/9-3-2024).
文摘BACKGROUND Prostatic artery embolization(PAE)is a promising but also technically demanding interventional radiologic treatment for symptomatic benign prostatic hyperplasia.Many technical challenges in PAE are associated with the complex anatomy of prostatic arteries(PAs)and with the systematic attempts to catheterize the PAs of both pelvic sides.Long procedure times and high radiation doses are often the result of these attempts and are considered significant disadvantages of PAE.The authors hypothesized that,in selected patients,these disadvantages could be mitigated by intentionally embolizing PAs of only one pelvic side.AIM To describe the authors’approach for intentionally unilateral PAE(IU-PAE)and its potential benefits.METHODS This was a single-center retrospective study of patients treated with IU-PAE during a period of 2 years.IU-PAE was applied in patients with opacification of more than half of the contralateral prostatic lobe after angiography of the ipsilateral PA(subgroup A),or with markedly asymmetric prostatic enlargement,with the dominant prostatic lobe occupying at least two thirds of the entire gland(subgroup B).All patients treated with IU-PAE also fulfilled at least one of the following criteria:Severe tortuosity or severe atheromatosis of the pelvic arteries,non-visualization,or visualization of a tiny(<1 mm)contralateral PA on preprocedural computed tomographic angiography.Intraprocedural contrast-enhanced ultrasonography(iCEUS)was applied to monitor prostatic infarction.IU-PAE patients were compared to a control group treated with bilateral PAE.RESULTS IU-PAE was performed in a total 13 patients(subgroup A,n=7;subgroup B,n=6).Dose-area product,fluoroscopy time and operation time in the IU-PAE group(9767.8μGy∙m^(2),30.3 minutes,64.0 minutes,respectively)were significantly shorter(45.4%,35.9%,45.8%respectively,P<0.01)compared to the control group.Clinical and imaging outcomes did not differ significantly between the IU-PAE group and the control group.In the 2 clinical failures of IU-PAE(both in subgroup A),the extent of prostatic infarction(demonstrated by iCEUS)was significantly smaller compared to the rest of the IU-PAE group.CONCLUSION In selected patients,IU-PAE is associated with comparable outcomes,but with lower radiation exposure and a shorter procedure compared to bilateral PAE.iCEUS could facilitate patient selection for IU-PAE.
