BACKGROUND Data on clinical characteristics,treatment outcomes,and prognosis of pancreatic primitive neuroectodermal tumors(PNETs)are limited.AIM To analyze the clinical data of 30 patients with pancreatic PNETs to id...BACKGROUND Data on clinical characteristics,treatment outcomes,and prognosis of pancreatic primitive neuroectodermal tumors(PNETs)are limited.AIM To analyze the clinical data of 30 patients with pancreatic PNETs to identify their clinical characteristics and factors associated with prognosis.METHODS We used the keywords"primary neuroectodermal tumor,""digestive tract,""pancreas,""pancreatic,"and"gastrointestinal,"individually or in combination,to collect data from a global database for all patients with pancreatic PNET to date.Univariate and Cox regression analyses were performed to identify prognostic factors for patient survival.RESULTS A total of 30 cases of pancreatic PNET were included in this study:15 males and 15 females with a mean age of 24 years.The main symptom was abdominal pain(73.3%),and the median tumor size was 7.85 cm.Twenty-four patients(80.0%)underwent surgery and nineteen patients received adjuvant therapy.Local metastasis was observed in 13 patients(43.3%),lymph node metastasis in 10 patients(33.3%),and distant metastasis in 6 patients(20.0%).Local recurrence was observed in 13 patients(43.3%).The median survival time of all patients was 29.4 months,and the overall estimated 1-year and 3-year survival rates were approximately 66.0%and 36.4%,respectively.Univariate analysis showed that chemotherapy(P=0.036),local metastasis(P=0.041),lymph node metastasis(P=0.003),distant metastasis(P=0.049),and surgical margins(P=0.048)were the prognostic factors affecting survival.Multivariate analysis revealed only lymph node metastasis(P=0.012)as a prognostic factor.CONCLUSION Pancreatic PNET is extremely rare,occurs in young adults,has no apparent sex predisposition,has a high rate of metastasis and early recurrence,and has a very poor prognosis.The diagnosis of pancreatic PNET requires a combination of clinical symptoms,pathologic features,immunohistochemistry,and cytogenetic analysis.Univariate analysis suggested that chemotherapy,metastasis,and surgical margins were prognostic factors affecting survival,and multivariate analysis suggested that lymph node metastasis is an important prognostic factor.Therefore,early diagnosis,early and extensive resection,and adjuvant chemoradiotherapy may help improve prognosis.展开更多
Path planning is crucial for autonomous flight of fixed-wing Unmanned Aerial Vehicles(UAVs).However,due to the high-speed flight and complex control of fixed-wing UAVs,ensuring the feasibility and safety of planned pa...Path planning is crucial for autonomous flight of fixed-wing Unmanned Aerial Vehicles(UAVs).However,due to the high-speed flight and complex control of fixed-wing UAVs,ensuring the feasibility and safety of planned paths in complex environments is challenging.This paper proposes a feasible path planning algorithm named Closed-loop Radial Ray A^(*)(CL-RaA^(*)).The core components of the CL-RaA^(*)include an adaptive variable-step-size path search and a just-in-time expansion primitive.The former enables fast path search in complex environments,while the latter ensures the feasibility of the generated paths.By integrating these two components and conducting safety checks on the trajectories to be expanded,the CL-RaA^(*)can rapidly generate safe and feasible paths that satisfy the differential constraints that comprehensively consider the dynamics and control characteristics of six-degree-of-freedom fixed-wing UAVs.The final performance tests and simulation validations demonstrate that the CL-RaA^(*)can generate safe and feasible paths in various environments.Compared to feasible path planning algorithms that use the rapidlyexploring random trees,the CL-RaA^(*)not only ensures deterministic planning results in the same scenarios but also generates smoother feasible paths for fixed-wing UAVs more efficiently.In environments with dense grid obstacles,the feasible paths generated by the CL-RaA^(*)are more conducive to UAV tracking compared to those planned using Dubins curves.展开更多
This paper investigates the ergodicity and weak convergence of transition probabilities for two-dimensional stochastic primitive equations driven by multiplicative noise.The existence of invariant measures is establis...This paper investigates the ergodicity and weak convergence of transition probabilities for two-dimensional stochastic primitive equations driven by multiplicative noise.The existence of invariant measures is established using the classical Krylov-Bogoliubov theory.The uniqueness of invariant measures and the weak convergence of transition probabilities are demonstrated through the application of the asymptotic coupling method and Foias-Prodi estimate.展开更多
Walking is the basic locomotion pattern for bipedal robots.The walking pattern is widely generated using the linear inverted pendulum model.The linear inverted pendulum motion of each support period can be designed as...Walking is the basic locomotion pattern for bipedal robots.The walking pattern is widely generated using the linear inverted pendulum model.The linear inverted pendulum motion of each support period can be designed as a walk primitive to be connected to form a walking trajectory.A novel method of integrating double support phase into the walk primitive was proposed in this article.The method describes the generation of walking patterns using walk primitives with double support,specifically for lateral plane including walking in place,walking for lateral,and walking initiation,and for sagittal plane including fixed step length walking,variable step length walking,and walking initiation.Compared to walk primitives without double support phase,those with double support phase reduce the maximum speed required by the robot and eliminate the need to adjust foothold for achieving continuous speed.The performance of the proposed method is validated by simulations and experiments on Neubot,a position-controlled biped robot.展开更多
The accelerating urbanization process leads to aggravated environmental problems, thus garden design which is a creative activity connecting human and nature has attracted much attention, and also garden designers hav...The accelerating urbanization process leads to aggravated environmental problems, thus garden design which is a creative activity connecting human and nature has attracted much attention, and also garden designers have had to rethink about environmental ethics and morals. This study, from the perspective of environmental ethics, duly proposed the brand-new concept of 'appropriate garden of primitive ecology', proceeded from the orientation, form, value, theoretical basis, realistic significance, culture and consumption psychology of 'garden of primitive ecology', fully developed outstanding ecological wisdoms and morals in traditional Chinese garden culture, boosted garden designs to the environmental ethics level of eco-justice, to seek for the approach to 'garden of primitive ecology' with indigenous Chinese environmental ethic characteristics.展开更多
This paper studies the problem of coordinated motion generation for a group of rigid bodies. Two classes of coordinated motion primitives, relative equilibria and ma- neuvers, are given as building blocks for generati...This paper studies the problem of coordinated motion generation for a group of rigid bodies. Two classes of coordinated motion primitives, relative equilibria and ma- neuvers, are given as building blocks for generating coordi- nated motions. In a motion-primitive based planning frame- work, a control method is proposed for the robust execution of a coordinated motion plan in the presence of perturba- tions. The control method combines the relative equilibria stabilization with maneuver design, and results in a close- loop motion planning framework. The performance of the control method has been illustrated through a numerical sim- ulation.展开更多
为了减小配电网带电作业的人身安全风险,降低电力系统的运维成本,文中设计了一种面向配电网作业的半人形智能机器人系统,包括硬件结构和控制系统设计。不同于绝缘杆作业法,该系统通过佩戴数据手套和腕部红外追踪器等多模态可穿戴设备来...为了减小配电网带电作业的人身安全风险,降低电力系统的运维成本,文中设计了一种面向配电网作业的半人形智能机器人系统,包括硬件结构和控制系统设计。不同于绝缘杆作业法,该系统通过佩戴数据手套和腕部红外追踪器等多模态可穿戴设备来捕捉人体动作和作业细节,并采用动态运动基元(dynamic movement primitives, DMP)将人体数据映射到半人形机器人的机械臂和末端灵巧手来进行配网作业。测试结果表明:所设计的半人形机器人系统能够稳定跟踪人体演示细节。在模拟配电网线路中可以完成多种作业功能,作业实验成功率可达88.9%。展开更多
This paper is devoted to considering the three-dimensional viscous primitive equations of the large-scale atmosphere. First, we prove the global well-posedness for the primitive equations with weaker initial data than...This paper is devoted to considering the three-dimensional viscous primitive equations of the large-scale atmosphere. First, we prove the global well-posedness for the primitive equations with weaker initial data than that in [11]. Second, we obtain the existence of smooth solutions to the equations. Moreover, we obtain the compact global attractor in V for the dynamical system generated by the primitive equations of large-scale atmosphere, which improves the result of [11].展开更多
Peripheral primitive neuroectodermal tumor(PNET) of the kidney is a rare, aggressive tumor known for its recurrence and metastatic potential. Despite the frequency of venous extension to the renal veins and inferior v...Peripheral primitive neuroectodermal tumor(PNET) of the kidney is a rare, aggressive tumor known for its recurrence and metastatic potential. Despite the frequency of venous extension to the renal veins and inferior vena cava, pulmonary tumor embolism at the initial presentation is not common. We report a case of 22-year-old female with PNET of the kidney who presented with tumor embolism in the inferior vena cava(IVC) and bilateral pulmonary artery. The patient underwent surgical resection and histopathological analysis confirmed the presence of tumor within the IVC and pulmonary arteries. The patient received adjuvant chemotherapy and is currently doing well on follow-up.展开更多
Non-acceleration theorem in a primitive equation system is developed to investigate the influences of waves on the mean flow variation against external forcing. Numerical results show that mechanical forcing overwhelm...Non-acceleration theorem in a primitive equation system is developed to investigate the influences of waves on the mean flow variation against external forcing. Numerical results show that mechanical forcing overwhelms thermal forcing in maintaining the mean flow in which the internal mechanical forcing associated with horizontal eddy flux of momentum plays the most important roles. Both internal forcing and external forcing are shown to be active and at the first place for the mean flow variations, whereas the forcing-induced mean meridional circulation is passive and secondary. It is also shown that the effects on mean flow of external mechanical forcing are concentrated in the lower troposphere, whereas those due to wave-mean flow interaction are more important in the upper troposphere. These act together and result in the vertically easterly shear in low latitudes and westerly shear in mid-latitudes. This vertical shear of mean flow is to some extent weakened by thermal forcing.展开更多
Extraskeletal Ewing's sarcoma/peripheral primitive neuroectodermal tumor(E-EWS/pP NET) is a rare aggressive malignant small round cell tumor. In this report, we present the case of a 15-year-old boy who suffered f...Extraskeletal Ewing's sarcoma/peripheral primitive neuroectodermal tumor(E-EWS/pP NET) is a rare aggressive malignant small round cell tumor. In this report, we present the case of a 15-year-old boy who suffered from acute abdominal pain accompanied by hematemesis and melena, and was eventually diagnosed with E-EWS/p PNET. To date, there have been only five reported cases of E-EWS/pP NET of the small bowel including the patient in this report. To the best of our knowledge, this is the first documentation of a pP NET of the small bowel mesentery at nonage. All these have made this report rare and significant.展开更多
Primitive neuroectodermal tumor (PNET) of the pancreas is an extremely rare tumor that usually occurs in children or young adults. We report a case of a 33-year-old male patient with an 18 cm × 18 cm × 16 cm...Primitive neuroectodermal tumor (PNET) of the pancreas is an extremely rare tumor that usually occurs in children or young adults. We report a case of a 33-year-old male patient with an 18 cm × 18 cm × 16 cm mass arising from the pancreatic body and tail with a one- day history of abdominal pain. Initial CT scan showed no signs of metastatic tumor spread. The tumor caused intrabdominal bleeding and the patient underwent primary tumor resection including partial gastrectomy, left pancreatic resection and splenectomy. Diagnosis of PNET was confi rmed by histology, immunohistochemistry and FISH analysis. All neoplastic cells were stained positive for MIC2-protein (CD99). Approximately one month after surgery, several liver metastases were observed and the patient underwent chemotherapy according to the Euro- Ewing protocol. Subsequent relaparotomy excluded any residual hepatic or extrahepatic abdominal metastases. Although PNET in the pancreas is an extremely rare entity, it should be considered in the diffential diagnosis of pancreatic masses, especially in young patients. This alarming case particularly illustrates that PNET in the pancreas although in an advanced stage can present with only a short history of mild symptoms.展开更多
The design of a total energy conserving semi-implicit scheme for the multiple-level baroclinic primitive equation has remained an unsolved problem for a long time. In this work, however, we follow an energy perfect co...The design of a total energy conserving semi-implicit scheme for the multiple-level baroclinic primitive equation has remained an unsolved problem for a long time. In this work, however, we follow an energy perfect conserving semi-implicit scheme of a European Centre for Medium-Range Weather Forecasts (ECMWF) type sigma-coordinate primitive equation which has recently successfully formulated. Some real-data contrast tests between the model of the new conserving scheme and that of the ECMWF-type of global spectral semi-implicit scheme show that the RMS error of the averaged forecast Height at 850 hPa can be clearly improved after the first integral week. The reduction also reaches 50 percent by the 30th day. Further contrast tests demonstrate that the RMS error of the monthly mean height in the middle and lower troposphere also be largely reduced, and some well-known systematical defects can be greatly improved. More detailed analysis reveals that part of the positive contributions comes from improvements of the extra-long wave components. This indicates that a remarkable improvement of the model climate drift level can be achieved by the actual realizing of a conserving time-difference scheme, which thereby eliminates a corresponding computational systematic error source/sink found in the currently-used traditional type of weather and climate system models in relation to the baroclinic primitive equations.展开更多
文摘BACKGROUND Data on clinical characteristics,treatment outcomes,and prognosis of pancreatic primitive neuroectodermal tumors(PNETs)are limited.AIM To analyze the clinical data of 30 patients with pancreatic PNETs to identify their clinical characteristics and factors associated with prognosis.METHODS We used the keywords"primary neuroectodermal tumor,""digestive tract,""pancreas,""pancreatic,"and"gastrointestinal,"individually or in combination,to collect data from a global database for all patients with pancreatic PNET to date.Univariate and Cox regression analyses were performed to identify prognostic factors for patient survival.RESULTS A total of 30 cases of pancreatic PNET were included in this study:15 males and 15 females with a mean age of 24 years.The main symptom was abdominal pain(73.3%),and the median tumor size was 7.85 cm.Twenty-four patients(80.0%)underwent surgery and nineteen patients received adjuvant therapy.Local metastasis was observed in 13 patients(43.3%),lymph node metastasis in 10 patients(33.3%),and distant metastasis in 6 patients(20.0%).Local recurrence was observed in 13 patients(43.3%).The median survival time of all patients was 29.4 months,and the overall estimated 1-year and 3-year survival rates were approximately 66.0%and 36.4%,respectively.Univariate analysis showed that chemotherapy(P=0.036),local metastasis(P=0.041),lymph node metastasis(P=0.003),distant metastasis(P=0.049),and surgical margins(P=0.048)were the prognostic factors affecting survival.Multivariate analysis revealed only lymph node metastasis(P=0.012)as a prognostic factor.CONCLUSION Pancreatic PNET is extremely rare,occurs in young adults,has no apparent sex predisposition,has a high rate of metastasis and early recurrence,and has a very poor prognosis.The diagnosis of pancreatic PNET requires a combination of clinical symptoms,pathologic features,immunohistochemistry,and cytogenetic analysis.Univariate analysis suggested that chemotherapy,metastasis,and surgical margins were prognostic factors affecting survival,and multivariate analysis suggested that lymph node metastasis is an important prognostic factor.Therefore,early diagnosis,early and extensive resection,and adjuvant chemoradiotherapy may help improve prognosis.
基金supported by the National Natural Science Foundation of China(No.52272382)the Fundamental Research Funds for the Central Universities,China。
文摘Path planning is crucial for autonomous flight of fixed-wing Unmanned Aerial Vehicles(UAVs).However,due to the high-speed flight and complex control of fixed-wing UAVs,ensuring the feasibility and safety of planned paths in complex environments is challenging.This paper proposes a feasible path planning algorithm named Closed-loop Radial Ray A^(*)(CL-RaA^(*)).The core components of the CL-RaA^(*)include an adaptive variable-step-size path search and a just-in-time expansion primitive.The former enables fast path search in complex environments,while the latter ensures the feasibility of the generated paths.By integrating these two components and conducting safety checks on the trajectories to be expanded,the CL-RaA^(*)can rapidly generate safe and feasible paths that satisfy the differential constraints that comprehensively consider the dynamics and control characteristics of six-degree-of-freedom fixed-wing UAVs.The final performance tests and simulation validations demonstrate that the CL-RaA^(*)can generate safe and feasible paths in various environments.Compared to feasible path planning algorithms that use the rapidlyexploring random trees,the CL-RaA^(*)not only ensures deterministic planning results in the same scenarios but also generates smoother feasible paths for fixed-wing UAVs more efficiently.In environments with dense grid obstacles,the feasible paths generated by the CL-RaA^(*)are more conducive to UAV tracking compared to those planned using Dubins curves.
基金supported in part by the NSFC(12171084,12326367)the Jiangsu Provincial Scientific Research Center of Applied Mathematics(BK20233002)the fundamental Research Funds for the Central Universities(RF1028623037)。
文摘This paper investigates the ergodicity and weak convergence of transition probabilities for two-dimensional stochastic primitive equations driven by multiplicative noise.The existence of invariant measures is established using the classical Krylov-Bogoliubov theory.The uniqueness of invariant measures and the weak convergence of transition probabilities are demonstrated through the application of the asymptotic coupling method and Foias-Prodi estimate.
基金supported in part by the National Key R&D Program under Grant 2018YFB1304504.
文摘Walking is the basic locomotion pattern for bipedal robots.The walking pattern is widely generated using the linear inverted pendulum model.The linear inverted pendulum motion of each support period can be designed as a walk primitive to be connected to form a walking trajectory.A novel method of integrating double support phase into the walk primitive was proposed in this article.The method describes the generation of walking patterns using walk primitives with double support,specifically for lateral plane including walking in place,walking for lateral,and walking initiation,and for sagittal plane including fixed step length walking,variable step length walking,and walking initiation.Compared to walk primitives without double support phase,those with double support phase reduce the maximum speed required by the robot and eliminate the need to adjust foothold for achieving continuous speed.The performance of the proposed method is validated by simulations and experiments on Neubot,a position-controlled biped robot.
文摘The accelerating urbanization process leads to aggravated environmental problems, thus garden design which is a creative activity connecting human and nature has attracted much attention, and also garden designers have had to rethink about environmental ethics and morals. This study, from the perspective of environmental ethics, duly proposed the brand-new concept of 'appropriate garden of primitive ecology', proceeded from the orientation, form, value, theoretical basis, realistic significance, culture and consumption psychology of 'garden of primitive ecology', fully developed outstanding ecological wisdoms and morals in traditional Chinese garden culture, boosted garden designs to the environmental ethics level of eco-justice, to seek for the approach to 'garden of primitive ecology' with indigenous Chinese environmental ethic characteristics.
基金supported by the National Natural Science Foundation of China (11072002,10832006)
文摘This paper studies the problem of coordinated motion generation for a group of rigid bodies. Two classes of coordinated motion primitives, relative equilibria and ma- neuvers, are given as building blocks for generating coordi- nated motions. In a motion-primitive based planning frame- work, a control method is proposed for the robust execution of a coordinated motion plan in the presence of perturba- tions. The control method combines the relative equilibria stabilization with maneuver design, and results in a close- loop motion planning framework. The performance of the control method has been illustrated through a numerical sim- ulation.
文摘为了减小配电网带电作业的人身安全风险,降低电力系统的运维成本,文中设计了一种面向配电网作业的半人形智能机器人系统,包括硬件结构和控制系统设计。不同于绝缘杆作业法,该系统通过佩戴数据手套和腕部红外追踪器等多模态可穿戴设备来捕捉人体动作和作业细节,并采用动态运动基元(dynamic movement primitives, DMP)将人体数据映射到半人形机器人的机械臂和末端灵巧手来进行配网作业。测试结果表明:所设计的半人形机器人系统能够稳定跟踪人体演示细节。在模拟配电网线路中可以完成多种作业功能,作业实验成功率可达88.9%。
基金supported in part by the NSF of China (90511009, 10801017)National Basic Research Program of China (973 Program, 2007CB814800)
文摘This paper is devoted to considering the three-dimensional viscous primitive equations of the large-scale atmosphere. First, we prove the global well-posedness for the primitive equations with weaker initial data than that in [11]. Second, we obtain the existence of smooth solutions to the equations. Moreover, we obtain the compact global attractor in V for the dynamical system generated by the primitive equations of large-scale atmosphere, which improves the result of [11].
文摘Peripheral primitive neuroectodermal tumor(PNET) of the kidney is a rare, aggressive tumor known for its recurrence and metastatic potential. Despite the frequency of venous extension to the renal veins and inferior vena cava, pulmonary tumor embolism at the initial presentation is not common. We report a case of 22-year-old female with PNET of the kidney who presented with tumor embolism in the inferior vena cava(IVC) and bilateral pulmonary artery. The patient underwent surgical resection and histopathological analysis confirmed the presence of tumor within the IVC and pulmonary arteries. The patient received adjuvant chemotherapy and is currently doing well on follow-up.
基金Research Project No.[75-09-01] on medium-range numerical weather forecasts.
文摘Non-acceleration theorem in a primitive equation system is developed to investigate the influences of waves on the mean flow variation against external forcing. Numerical results show that mechanical forcing overwhelms thermal forcing in maintaining the mean flow in which the internal mechanical forcing associated with horizontal eddy flux of momentum plays the most important roles. Both internal forcing and external forcing are shown to be active and at the first place for the mean flow variations, whereas the forcing-induced mean meridional circulation is passive and secondary. It is also shown that the effects on mean flow of external mechanical forcing are concentrated in the lower troposphere, whereas those due to wave-mean flow interaction are more important in the upper troposphere. These act together and result in the vertically easterly shear in low latitudes and westerly shear in mid-latitudes. This vertical shear of mean flow is to some extent weakened by thermal forcing.
文摘Extraskeletal Ewing's sarcoma/peripheral primitive neuroectodermal tumor(E-EWS/pP NET) is a rare aggressive malignant small round cell tumor. In this report, we present the case of a 15-year-old boy who suffered from acute abdominal pain accompanied by hematemesis and melena, and was eventually diagnosed with E-EWS/p PNET. To date, there have been only five reported cases of E-EWS/pP NET of the small bowel including the patient in this report. To the best of our knowledge, this is the first documentation of a pP NET of the small bowel mesentery at nonage. All these have made this report rare and significant.
文摘Primitive neuroectodermal tumor (PNET) of the pancreas is an extremely rare tumor that usually occurs in children or young adults. We report a case of a 33-year-old male patient with an 18 cm × 18 cm × 16 cm mass arising from the pancreatic body and tail with a one- day history of abdominal pain. Initial CT scan showed no signs of metastatic tumor spread. The tumor caused intrabdominal bleeding and the patient underwent primary tumor resection including partial gastrectomy, left pancreatic resection and splenectomy. Diagnosis of PNET was confi rmed by histology, immunohistochemistry and FISH analysis. All neoplastic cells were stained positive for MIC2-protein (CD99). Approximately one month after surgery, several liver metastases were observed and the patient underwent chemotherapy according to the Euro- Ewing protocol. Subsequent relaparotomy excluded any residual hepatic or extrahepatic abdominal metastases. Although PNET in the pancreas is an extremely rare entity, it should be considered in the diffential diagnosis of pancreatic masses, especially in young patients. This alarming case particularly illustrates that PNET in the pancreas although in an advanced stage can present with only a short history of mild symptoms.
基金This research was jointly supported by the National Key Programme for Developing Basic Sciences (G1998040911) and the National Natural Science Foundation of China under Grant Nos. 49675267, 49205058, and 49975020.
文摘The design of a total energy conserving semi-implicit scheme for the multiple-level baroclinic primitive equation has remained an unsolved problem for a long time. In this work, however, we follow an energy perfect conserving semi-implicit scheme of a European Centre for Medium-Range Weather Forecasts (ECMWF) type sigma-coordinate primitive equation which has recently successfully formulated. Some real-data contrast tests between the model of the new conserving scheme and that of the ECMWF-type of global spectral semi-implicit scheme show that the RMS error of the averaged forecast Height at 850 hPa can be clearly improved after the first integral week. The reduction also reaches 50 percent by the 30th day. Further contrast tests demonstrate that the RMS error of the monthly mean height in the middle and lower troposphere also be largely reduced, and some well-known systematical defects can be greatly improved. More detailed analysis reveals that part of the positive contributions comes from improvements of the extra-long wave components. This indicates that a remarkable improvement of the model climate drift level can be achieved by the actual realizing of a conserving time-difference scheme, which thereby eliminates a corresponding computational systematic error source/sink found in the currently-used traditional type of weather and climate system models in relation to the baroclinic primitive equations.
