The Mediterranean diet has long been recognized as one of the most effective ways to prevent and improve cardiovascular disease.Extra virgin olive oil(EVOO)is the typical sources of fat in the Mediterranean diet which...The Mediterranean diet has long been recognized as one of the most effective ways to prevent and improve cardiovascular disease.Extra virgin olive oil(EVOO)is the typical sources of fat in the Mediterranean diet which have been shown to have noteworthy nutritional value and positive impact on human health.It is worth noting that EVOO owes its superior nutritional value to its bioactive composition.The main component of EVOO is monounsaturated fatty acids(MUFAs)in the form of oleic acid.Oleic acid accounts for up to 70%-80%of EVOO.Secondly,EVOO contains approximately more than 30 phenolic compounds,of which HT is essential for the protection against cardiovascular diseases.In this review,we focused on the potential mechanisms of oleic acid and polyphenols combat cardiovascular diseases risk in terms of oxidative stress,inflammation,blood pressure,endothelial function and cholesterol.This review might provide a reference for the studies on cardiovascular protective effects of EVOO.展开更多
Background:Hodgkin lymphoma refers to a malignancy of the lymphatic tissue.Extra-nodal Hodgkin lymphoma(ENHL)is a rare variant consisting of Hodgkin lymphoma occurring outside the lymphatic system.Studies investigatin...Background:Hodgkin lymphoma refers to a malignancy of the lymphatic tissue.Extra-nodal Hodgkin lymphoma(ENHL)is a rare variant consisting of Hodgkin lymphoma occurring outside the lymphatic system.Studies investigating the epidemiology associated with ENHL are rare.Methods:618 ENHL cases were analyzed using the National Cancer Institute’s Surveillance,Epidemiology,and End Results(SEER)database(2000–2020).Demographics including sex,race/ethnicity,rural-urban continuum,age group(categorized as adolescent and young adult(AYA)if between years of 15 and 39,and adult if over the age of 40),and living status(alive/deceased)were examined,with survival status as the main outcome.Results:This study included 335 males(54.2%)and 283 females(45.8%).Of this total,47.9%were in the AYA group.In terms of ethnicity the distribution was 12.5%non-Hispanic Black,67.5%non-Hispanic White,5.2%non-Hispanic Asian/Pacific Islander,and 14.9%Hispanic.Bivariate analyses evidenced significant differences in survival by age group with 91.6%in AYA vs.72.4%in adults(P<0.001)alive by the end of the study period.Multivariable analyses identified age as a key predictor of survival,as the AYA patients had a lower odds ratio for death(odds ratio=0.25,P<0.001).In addition,survival outcomes were also impacted by race,with non-Hispanic Blacks showing higher survival probabilities.Regarding treatment,27.0%of patients underwent surgery,with 10.2%receiving post-surgery radiation,reducing odds of mortality(odds ratio=0.32,P=0.046).Conclusion:The background research as such,tends to affirm that these two factors–age and race are quite crucial in the prognosis as well as management of ENHL.Compared to adults,AYA patients had significantly lower odds of death,while non-Hispanic Black individuals exhibited reduced survival probabilities.It should be noted that 27.0%of patients underwent surgery with 10.2%receiving post-operative radiation which led to decrease in mortality rates.Thus,these results reiterate the necessity for tailor-made treatment methods according to demographic characteristics to boost patient outcomes effectively.For better ENHL care,future studies could shed light on these disparities and improve treatment regimens as needed.展开更多
Background: A number of meningeal neoplastic lesions may radiologically and clinically simulate meningioma, include hemangiopericytomas, solitary fibrous tumors, schwannomas, hematolymphoid lesions, metastases, and ot...Background: A number of meningeal neoplastic lesions may radiologically and clinically simulate meningioma, include hemangiopericytomas, solitary fibrous tumors, schwannomas, hematolymphoid lesions, metastases, and others very rarely, also may clinically mimic meningiomas. Case Description: We present the case of A 28-year-old male patient, with no notable medical history, who presented with worsening headaches for 3 months, imbalance, and visual deficits, An initial MRI revealed extra-axial lesion involving the right Parieto-occipital, The tumor was hypointense on T1-weighted MR images, hyperintense signals on T2-weightedMR images, and heterogeneously enhanced suggestive of a meningioma, total resection was achieved, and the histopathological analysis confirmed the diagnosis of an angioblastic meningioma. However, 15 months later, the patient presented with the same initial visual complaints. A subsequent MRI showed lesion recurrence, leading to a second surgical intervention. The histopathological analysis confirmed the diagnosis of an anaplastic xanthoastrocytoma. Conclusion: This represents an unusual location for an anaplastic pleomorphic xanthoastrocytoma, which should broaden the differential diagnosis of extra-axial lesions.展开更多
In order to clarify the danger of water breakout in the bottom plate of extra-thick coal seam mining, 2202 working face of a mine in the west is taken as the research object, and it is proposed to use the on-site moni...In order to clarify the danger of water breakout in the bottom plate of extra-thick coal seam mining, 2202 working face of a mine in the west is taken as the research object, and it is proposed to use the on-site monitoring means combining borehole peeping and microseismic monitoring, combined with the theoretical analysis to analyze the danger of water breakout in the bottom plate. The results show that: 1) the theoretically calculated maximum damage depth of the bottom plate is 27.5 m, and its layer is located above the Austrian ash aquifer, which has the danger of water breakout;2) the drill hole peeping at the bottom plate of the working face shows that the depth of the bottom plate fissure development reaches 26 m, and the integrity of the water barrier layer has been damaged, so there is the risk of water breakout;3) for the microseismic monitoring of the anomalous area, the bottom plate of the return air downstream channel occurs in the field with a one-week lag, which shows that microseismic monitoring events may reflect the water breakout of the underground. This shows that the microseismic monitoring events can reflect the changes of the underground flow field, which can provide a reference basis for the early warning of water breakout. The research results can provide reference for the prediction of sudden water hazard.展开更多
Based on the analysis of the basic characteristics of medium-and large-sized marine gas fields in Sichuan Basin, combined with the division of major reservoir forming geological units in the marine craton stage and th...Based on the analysis of the basic characteristics of medium-and large-sized marine gas fields in Sichuan Basin, combined with the division of major reservoir forming geological units in the marine craton stage and their control on key hydrocarbon accumulation factors, the distribution law of medium-and large-sized marine carbonate gas fields in the basin was examined and the exploration direction was pointed out. Through the analysis of the periodic stretching-uplifting background, it is concluded that five large scale paleo-rifts, three large scale paleo-uplifts, five large scale paleo erosion surfaces were formed in the marine craton stage of Sichuan Basin, and these geological units control the key reservoir forming factors of medium and large sized gas fields:(1) Large-scale paleo-rifts control the distribution of high-quality hydrocarbon generation centers.(2) The margin of large-scale paleo-rifts, high position of paleo-uplifts and paleo erosion surfaces control the distribution of high-quality reservoirs.(3) Large-scale paleo-rifts, paleo-uplifts, paleo erosion surfaces and present tectonic setting jointly control the formation of many types of large and medium-sized traps.(4) Natural gas accumulation is controlled by the inheritance evolution of traps in large geological units. Based on the comparative analysis of the distribution characteristics of medium-and large-sized gas fields and large geological units, it is proposed that the superimposition relationship between single or multiple geological units and the present structure controls the distribution of medium-and large-sized gas fields, and the "three paleo" superimposed area is the most advantageous. According to the above rules, the main exploration fields and directions of medium-and large-sized marine carbonate gas fields in Sichuan Basin include periphery of Deyang-Anyue paleo-rift, eastern margin of Longmenshan paleo-rift, margins of Kaijiang-Liangping oceanic trough and Chengkou-western Hubei oceanic trough, the high part of the subaqueous paleo-uplifts around Central Sichuan, paleo erosion surfaces of the top boundary of Maokou Formation in eastern and southern Sichuan Basin, paleo erosion surfaces of the top boundary of the Leikoupo Formation in central and western Sichuan Basin.展开更多
When heavy machines and large scaled receiver system of communication equipment are manufactured, it always needs to produce large-sized steel castings, aluminum castings and etc. Some defects of hot cracking by therm...When heavy machines and large scaled receiver system of communication equipment are manufactured, it always needs to produce large-sized steel castings, aluminum castings and etc. Some defects of hot cracking by thermal stress often appear during solidification process as these castings are produced, which results in failure of castings. Therefore predicting the effects of technological parameters for production of castings on the thermal stress during solidification process becomes an important means. In this paper, the mathematical models have been established and numerical calculation of temperature fields by using finite difference method (FDM) and then thermal stress fields by using finite element method (FEM) during solidification process of castings have been carried out. The technological parameters of production have been optimized by the results of calculation and the defects of hot cracking have been eliminated. Modeling and simulation of 3D thermal stress during solidification processes of large-sized castings provided a scientific basis, which promoted further development of advanced manufacturing technique.展开更多
Recently, research strives to apply Ultra High Performance Concrete (UHPC) to large-sized structures owing to its remarkable mechanical performance and durability compared to normal concrete. The Korea Institute of Co...Recently, research strives to apply Ultra High Performance Concrete (UHPC) to large-sized structures owing to its remarkable mechanical performance and durability compared to normal concrete. The Korea Institute of Construction Technology proposed SuperBridge800, an edge girder type UHPC cable stayed bridge with central span of 800 m, through its detailed design. The bridge is designed to be erected through the connection of precast UHPC segments. The precast UHPC segment is monolithically composed of one ribbed deck slab and edge girders at each side. The connection between the precast segments is achieved by steel bars at the edge girders and by UHPC cast-in-place wet joint at the slab. Despite of the outstanding mechanical performance of UHPC, the fabrication of large-sized members is a difficult task since UHPC hardens faster than normal concrete and requires a special curing process. Therefore, the constructability of large-sized UHPC segment should be secured to achieve SuperBridge800. Besides, the performance of the connection between segments should also be guaranteed, especially in terms of the fatigue performance of the UHPC cast-in-place joint, which constitutes a weak point. To that goal, two half-scaled UHPC segments are manufactured and the constructability is examined by fabricating a large-sized UHPC member connected with respect to the design conditions. This study conducts rolling fatigue test on the so-fabricated large-sized UHPC member. Rolling fatigue test is carried out up to 2 million cycles considering actual vehicle load at each center and quarter points of the member. The test results confirm that the service limit state is satisfied.展开更多
Large-sized aluminum tube has big section effect, aspect ratio and thin thickness, so that the extrusion technology is complex and the large specific pressure is generated in extrusion cavity. The temperature variatio...Large-sized aluminum tube has big section effect, aspect ratio and thin thickness, so that the extrusion technology is complex and the large specific pressure is generated in extrusion cavity. The temperature variation and velocity effect is difficult to control. The extrusion forming of large-sized aluminum tube was researched and simulated. Three-dimensional thermo-mechanical coupled finite element model was constructed and appropriate boundary conditions were given out. The results show that large-sized aluminum tube can be formed by isothermal extrusion through controlling the extrusion velocity and founding the relationship between extrusion velocity and extrusion temperature.展开更多
This study considered and predicted blast-induced ground vibration(PPV)in open-pit mines using bagging and sibling techniques under the rigorous combination of machine learning algorithms.Accordingly,four machine lear...This study considered and predicted blast-induced ground vibration(PPV)in open-pit mines using bagging and sibling techniques under the rigorous combination of machine learning algorithms.Accordingly,four machine learning algorithms,including support vector regression(SVR),extra trees(ExTree),K-nearest neighbors(KNN),and decision tree regression(DTR),were used as the base models for the purposes of combination and PPV initial prediction.The bagging regressor(BA)was then applied to combine these base models with the efforts of variance reduction,overfitting elimination,and generating more robust predictive models,abbreviated as BA-ExTree,BAKNN,BA-SVR,and BA-DTR.It is emphasized that the ExTree model has not been considered for predicting blastinduced ground vibration before,and the bagging of ExTree is an innovation aiming to improve the accuracy of the inherently ExTree model,as well.In addition,two empirical models(i.e.,USBM and Ambraseys)were also treated and compared with the bagging models to gain a comprehensive assessment.With this aim,we collected 300 blasting events with different parameters at the Sin Quyen copper mine(Vietnam),and the produced PPV values were also measured.They were then compiled as the dataset to develop the PPV predictive models.The results revealed that the bagging models provided better performance than the empirical models,except for the BA-DTR model.Of those,the BA-ExTree is the best model with the highest accuracy(i.e.,88.8%).Whereas,the empirical models only provided the accuracy from 73.6%–76%.The details of comparisons and assessments were also presented in this study.展开更多
Introduction: Primary extra-gastrointestinal stromal tumors (E-GIST) of the liver are rare. The clinical presentation can range from asymptomatic to bleeding or manifestations of mass effect. Cancer surgery followed b...Introduction: Primary extra-gastrointestinal stromal tumors (E-GIST) of the liver are rare. The clinical presentation can range from asymptomatic to bleeding or manifestations of mass effect. Cancer surgery followed by adjuvant treatment with imatinib is the standard of care. However, in special circumstances, a cytoreductive approach may represent a therapeutic option. We describe here the case of two patients who presented with a painful and protruding epigastric mass, the first case was a localized E-GIST candidate for neoadjuvant treatment with imatinib with complete resection surgery thereafter with very good evolution, and the second is that of an E-GIST of the liver at an advanced stage with an evolution very quick to death. Conclusion: Primary liver E-GIST is a rare condition. Treatment is based on systemic therapy and total resection surgery. However, cytoreductive surgery will be required when complete resection is not possible.展开更多
It is well-known that connectivity is closely related to diagnosability.If the relationships be-tween them can be established,many kinds of diagnosability will be determined directly.So far,some notable relationships ...It is well-known that connectivity is closely related to diagnosability.If the relationships be-tween them can be established,many kinds of diagnosability will be determined directly.So far,some notable relationships between connectivity and diagnosability had been revealed.This paper in-tends to find out the relationship between extra connectivity and t/k-diagnosability under the PMC(Preparata,Metze,and Chien)model.Then,applying this relationship,the t/k-diagnosability of bijective connection(BC)networks are determined conveniently.展开更多
BACKGROUND Veno-arterial extra corporeal membrane oxygenation(VA-ECMO)support is commonly complicated with left ventricle(LV)distension in patients with cardiogenic shock.We resolved this problem by transeptally conve...BACKGROUND Veno-arterial extra corporeal membrane oxygenation(VA-ECMO)support is commonly complicated with left ventricle(LV)distension in patients with cardiogenic shock.We resolved this problem by transeptally converting VAECMO to left atrium veno-arterial(LAVA)-ECMO that functioned as a temporary paracorporeal left ventricular assist device to resolve LV distension.In our case LAVA-ECMO was also functioning as a bridge-to-transplant device,a technique that has been scarcely reported in the literature.CASE SUMMARY A 65 year-old man suffered from acute myocardial injury that required percutaneous stents.Less than two weeks later,noncompliance to antiplatelet therapy led to stent thrombosis,cardiogenic shock,and cardiac arrest.Femorofemoral VA-ECMO support was started,and the patient underwent a second coronary angiography with re-stenting and intra-aortic balloon pump placement.The VA-ECMO support was complicated by left ventricular distension which we resolved via LAVA-ECMO.Unfortunately,episodes of bleeding and sepsis complicated the clinical picture and the patient passed away 27 d after initiating VA-ECMO.CONCLUSION This clinical case demonstrates that LAVA-ECMO is a viable strategy to unload the LV without another invasive percutaneous or surgical procedure.We also demonstrate that LAVA-ECMO can also be weaned to a left ventricular assist device system.A benefit of this technique is that the procedure is potentially reversible,should the patient require VA-ECMO support again.A transeptal LV venting approach like LAVA-ECMO may be indicated over ImpellaTM in cases where less LV unloading is required and where a restrictive myocardium could cause LV suctioning.Left ventricular over-distention is a well-known complication of peripheral VA-ECMO in cardiogenic shock and LAVA ECMO through transeptal cannulation offers a novel and safe approach for treating LV overloading,without the need of an additional percutaneous access.展开更多
The main goal of this paper is to determine the effect of an extra dimension on a traversable wormhole. Here an earlier study by the author [Phys. Rev. D 98, 064041 (2018)] is extended in several significant ways. To ...The main goal of this paper is to determine the effect of an extra dimension on a traversable wormhole. Here an earlier study by the author [Phys. Rev. D 98, 064041 (2018)] is extended in several significant ways. To begin with, the extra spatial dimension is assumed to be time dependent, while the redshift and shape functions, as well as the extra dimension, are functions of both r and l, the respective radial and extra coordinates;the last of these is therefore a function of r, l, and t. The main objective is to determine the conditions that allow the throat of the wormhole to be threaded with ordinary matter (by respecting the null energy condition) and that the same conditions lead to a violation of the null energy condition in the fifth dimension, which is therefore responsible for sustaining the wormhole. The dependence of the extra dimension on l and t is subject to additional conditions that are subsequently analyzed in this paper. Finally, the extra dimension may be extremely small or even curled up.展开更多
基金supported by the CACMS Innovation Fund(CI2021A00914)the Beijing Novaprogram(Z211100002121062)+1 种基金the Opening Project of the Key Laboratory of Integrative Chinese and Western Medicine for the Diagnosis and Treatment of Circulatory Diseases of Zhejiang Province(2C32001)the National Natural Science Foundation of China(82004193)。
文摘The Mediterranean diet has long been recognized as one of the most effective ways to prevent and improve cardiovascular disease.Extra virgin olive oil(EVOO)is the typical sources of fat in the Mediterranean diet which have been shown to have noteworthy nutritional value and positive impact on human health.It is worth noting that EVOO owes its superior nutritional value to its bioactive composition.The main component of EVOO is monounsaturated fatty acids(MUFAs)in the form of oleic acid.Oleic acid accounts for up to 70%-80%of EVOO.Secondly,EVOO contains approximately more than 30 phenolic compounds,of which HT is essential for the protection against cardiovascular diseases.In this review,we focused on the potential mechanisms of oleic acid and polyphenols combat cardiovascular diseases risk in terms of oxidative stress,inflammation,blood pressure,endothelial function and cholesterol.This review might provide a reference for the studies on cardiovascular protective effects of EVOO.
文摘Background:Hodgkin lymphoma refers to a malignancy of the lymphatic tissue.Extra-nodal Hodgkin lymphoma(ENHL)is a rare variant consisting of Hodgkin lymphoma occurring outside the lymphatic system.Studies investigating the epidemiology associated with ENHL are rare.Methods:618 ENHL cases were analyzed using the National Cancer Institute’s Surveillance,Epidemiology,and End Results(SEER)database(2000–2020).Demographics including sex,race/ethnicity,rural-urban continuum,age group(categorized as adolescent and young adult(AYA)if between years of 15 and 39,and adult if over the age of 40),and living status(alive/deceased)were examined,with survival status as the main outcome.Results:This study included 335 males(54.2%)and 283 females(45.8%).Of this total,47.9%were in the AYA group.In terms of ethnicity the distribution was 12.5%non-Hispanic Black,67.5%non-Hispanic White,5.2%non-Hispanic Asian/Pacific Islander,and 14.9%Hispanic.Bivariate analyses evidenced significant differences in survival by age group with 91.6%in AYA vs.72.4%in adults(P<0.001)alive by the end of the study period.Multivariable analyses identified age as a key predictor of survival,as the AYA patients had a lower odds ratio for death(odds ratio=0.25,P<0.001).In addition,survival outcomes were also impacted by race,with non-Hispanic Blacks showing higher survival probabilities.Regarding treatment,27.0%of patients underwent surgery,with 10.2%receiving post-surgery radiation,reducing odds of mortality(odds ratio=0.32,P=0.046).Conclusion:The background research as such,tends to affirm that these two factors–age and race are quite crucial in the prognosis as well as management of ENHL.Compared to adults,AYA patients had significantly lower odds of death,while non-Hispanic Black individuals exhibited reduced survival probabilities.It should be noted that 27.0%of patients underwent surgery with 10.2%receiving post-operative radiation which led to decrease in mortality rates.Thus,these results reiterate the necessity for tailor-made treatment methods according to demographic characteristics to boost patient outcomes effectively.For better ENHL care,future studies could shed light on these disparities and improve treatment regimens as needed.
文摘Background: A number of meningeal neoplastic lesions may radiologically and clinically simulate meningioma, include hemangiopericytomas, solitary fibrous tumors, schwannomas, hematolymphoid lesions, metastases, and others very rarely, also may clinically mimic meningiomas. Case Description: We present the case of A 28-year-old male patient, with no notable medical history, who presented with worsening headaches for 3 months, imbalance, and visual deficits, An initial MRI revealed extra-axial lesion involving the right Parieto-occipital, The tumor was hypointense on T1-weighted MR images, hyperintense signals on T2-weightedMR images, and heterogeneously enhanced suggestive of a meningioma, total resection was achieved, and the histopathological analysis confirmed the diagnosis of an angioblastic meningioma. However, 15 months later, the patient presented with the same initial visual complaints. A subsequent MRI showed lesion recurrence, leading to a second surgical intervention. The histopathological analysis confirmed the diagnosis of an anaplastic xanthoastrocytoma. Conclusion: This represents an unusual location for an anaplastic pleomorphic xanthoastrocytoma, which should broaden the differential diagnosis of extra-axial lesions.
文摘In order to clarify the danger of water breakout in the bottom plate of extra-thick coal seam mining, 2202 working face of a mine in the west is taken as the research object, and it is proposed to use the on-site monitoring means combining borehole peeping and microseismic monitoring, combined with the theoretical analysis to analyze the danger of water breakout in the bottom plate. The results show that: 1) the theoretically calculated maximum damage depth of the bottom plate is 27.5 m, and its layer is located above the Austrian ash aquifer, which has the danger of water breakout;2) the drill hole peeping at the bottom plate of the working face shows that the depth of the bottom plate fissure development reaches 26 m, and the integrity of the water barrier layer has been damaged, so there is the risk of water breakout;3) for the microseismic monitoring of the anomalous area, the bottom plate of the return air downstream channel occurs in the field with a one-week lag, which shows that microseismic monitoring events may reflect the water breakout of the underground. This shows that the microseismic monitoring events can reflect the changes of the underground flow field, which can provide a reference basis for the early warning of water breakout. The research results can provide reference for the prediction of sudden water hazard.
基金Supported by the China National Science and Technology Major Project(2016ZX05007004,2016ZX05004005)
文摘Based on the analysis of the basic characteristics of medium-and large-sized marine gas fields in Sichuan Basin, combined with the division of major reservoir forming geological units in the marine craton stage and their control on key hydrocarbon accumulation factors, the distribution law of medium-and large-sized marine carbonate gas fields in the basin was examined and the exploration direction was pointed out. Through the analysis of the periodic stretching-uplifting background, it is concluded that five large scale paleo-rifts, three large scale paleo-uplifts, five large scale paleo erosion surfaces were formed in the marine craton stage of Sichuan Basin, and these geological units control the key reservoir forming factors of medium and large sized gas fields:(1) Large-scale paleo-rifts control the distribution of high-quality hydrocarbon generation centers.(2) The margin of large-scale paleo-rifts, high position of paleo-uplifts and paleo erosion surfaces control the distribution of high-quality reservoirs.(3) Large-scale paleo-rifts, paleo-uplifts, paleo erosion surfaces and present tectonic setting jointly control the formation of many types of large and medium-sized traps.(4) Natural gas accumulation is controlled by the inheritance evolution of traps in large geological units. Based on the comparative analysis of the distribution characteristics of medium-and large-sized gas fields and large geological units, it is proposed that the superimposition relationship between single or multiple geological units and the present structure controls the distribution of medium-and large-sized gas fields, and the "three paleo" superimposed area is the most advantageous. According to the above rules, the main exploration fields and directions of medium-and large-sized marine carbonate gas fields in Sichuan Basin include periphery of Deyang-Anyue paleo-rift, eastern margin of Longmenshan paleo-rift, margins of Kaijiang-Liangping oceanic trough and Chengkou-western Hubei oceanic trough, the high part of the subaqueous paleo-uplifts around Central Sichuan, paleo erosion surfaces of the top boundary of Maokou Formation in eastern and southern Sichuan Basin, paleo erosion surfaces of the top boundary of the Leikoupo Formation in central and western Sichuan Basin.
文摘When heavy machines and large scaled receiver system of communication equipment are manufactured, it always needs to produce large-sized steel castings, aluminum castings and etc. Some defects of hot cracking by thermal stress often appear during solidification process as these castings are produced, which results in failure of castings. Therefore predicting the effects of technological parameters for production of castings on the thermal stress during solidification process becomes an important means. In this paper, the mathematical models have been established and numerical calculation of temperature fields by using finite difference method (FDM) and then thermal stress fields by using finite element method (FEM) during solidification process of castings have been carried out. The technological parameters of production have been optimized by the results of calculation and the defects of hot cracking have been eliminated. Modeling and simulation of 3D thermal stress during solidification processes of large-sized castings provided a scientific basis, which promoted further development of advanced manufacturing technique.
文摘Recently, research strives to apply Ultra High Performance Concrete (UHPC) to large-sized structures owing to its remarkable mechanical performance and durability compared to normal concrete. The Korea Institute of Construction Technology proposed SuperBridge800, an edge girder type UHPC cable stayed bridge with central span of 800 m, through its detailed design. The bridge is designed to be erected through the connection of precast UHPC segments. The precast UHPC segment is monolithically composed of one ribbed deck slab and edge girders at each side. The connection between the precast segments is achieved by steel bars at the edge girders and by UHPC cast-in-place wet joint at the slab. Despite of the outstanding mechanical performance of UHPC, the fabrication of large-sized members is a difficult task since UHPC hardens faster than normal concrete and requires a special curing process. Therefore, the constructability of large-sized UHPC segment should be secured to achieve SuperBridge800. Besides, the performance of the connection between segments should also be guaranteed, especially in terms of the fatigue performance of the UHPC cast-in-place joint, which constitutes a weak point. To that goal, two half-scaled UHPC segments are manufactured and the constructability is examined by fabricating a large-sized UHPC member connected with respect to the design conditions. This study conducts rolling fatigue test on the so-fabricated large-sized UHPC member. Rolling fatigue test is carried out up to 2 million cycles considering actual vehicle load at each center and quarter points of the member. The test results confirm that the service limit state is satisfied.
文摘Large-sized aluminum tube has big section effect, aspect ratio and thin thickness, so that the extrusion technology is complex and the large specific pressure is generated in extrusion cavity. The temperature variation and velocity effect is difficult to control. The extrusion forming of large-sized aluminum tube was researched and simulated. Three-dimensional thermo-mechanical coupled finite element model was constructed and appropriate boundary conditions were given out. The results show that large-sized aluminum tube can be formed by isothermal extrusion through controlling the extrusion velocity and founding the relationship between extrusion velocity and extrusion temperature.
基金funded by Vietnam National Foundation for Science and Tech-nology Development(NAFOSTED)under Grant No.105.99-2019.309.
文摘This study considered and predicted blast-induced ground vibration(PPV)in open-pit mines using bagging and sibling techniques under the rigorous combination of machine learning algorithms.Accordingly,four machine learning algorithms,including support vector regression(SVR),extra trees(ExTree),K-nearest neighbors(KNN),and decision tree regression(DTR),were used as the base models for the purposes of combination and PPV initial prediction.The bagging regressor(BA)was then applied to combine these base models with the efforts of variance reduction,overfitting elimination,and generating more robust predictive models,abbreviated as BA-ExTree,BAKNN,BA-SVR,and BA-DTR.It is emphasized that the ExTree model has not been considered for predicting blastinduced ground vibration before,and the bagging of ExTree is an innovation aiming to improve the accuracy of the inherently ExTree model,as well.In addition,two empirical models(i.e.,USBM and Ambraseys)were also treated and compared with the bagging models to gain a comprehensive assessment.With this aim,we collected 300 blasting events with different parameters at the Sin Quyen copper mine(Vietnam),and the produced PPV values were also measured.They were then compiled as the dataset to develop the PPV predictive models.The results revealed that the bagging models provided better performance than the empirical models,except for the BA-DTR model.Of those,the BA-ExTree is the best model with the highest accuracy(i.e.,88.8%).Whereas,the empirical models only provided the accuracy from 73.6%–76%.The details of comparisons and assessments were also presented in this study.
文摘Introduction: Primary extra-gastrointestinal stromal tumors (E-GIST) of the liver are rare. The clinical presentation can range from asymptomatic to bleeding or manifestations of mass effect. Cancer surgery followed by adjuvant treatment with imatinib is the standard of care. However, in special circumstances, a cytoreductive approach may represent a therapeutic option. We describe here the case of two patients who presented with a painful and protruding epigastric mass, the first case was a localized E-GIST candidate for neoadjuvant treatment with imatinib with complete resection surgery thereafter with very good evolution, and the second is that of an E-GIST of the liver at an advanced stage with an evolution very quick to death. Conclusion: Primary liver E-GIST is a rare condition. Treatment is based on systemic therapy and total resection surgery. However, cytoreductive surgery will be required when complete resection is not possible.
基金Supported by the National Natural Science Foundation of China(No.62262032,61862035,61562046)National Natural Science Foundation of Jiangxi Province(No.20202BABL202042)the Science and Technology Project of Jiangxi Provincial Education Department(No.GJJ2201604,GJJ201033,GJJ190560).
文摘It is well-known that connectivity is closely related to diagnosability.If the relationships be-tween them can be established,many kinds of diagnosability will be determined directly.So far,some notable relationships between connectivity and diagnosability had been revealed.This paper in-tends to find out the relationship between extra connectivity and t/k-diagnosability under the PMC(Preparata,Metze,and Chien)model.Then,applying this relationship,the t/k-diagnosability of bijective connection(BC)networks are determined conveniently.
基金Supported by EUROSETS srl Italy for the Open Access Fee.
文摘BACKGROUND Veno-arterial extra corporeal membrane oxygenation(VA-ECMO)support is commonly complicated with left ventricle(LV)distension in patients with cardiogenic shock.We resolved this problem by transeptally converting VAECMO to left atrium veno-arterial(LAVA)-ECMO that functioned as a temporary paracorporeal left ventricular assist device to resolve LV distension.In our case LAVA-ECMO was also functioning as a bridge-to-transplant device,a technique that has been scarcely reported in the literature.CASE SUMMARY A 65 year-old man suffered from acute myocardial injury that required percutaneous stents.Less than two weeks later,noncompliance to antiplatelet therapy led to stent thrombosis,cardiogenic shock,and cardiac arrest.Femorofemoral VA-ECMO support was started,and the patient underwent a second coronary angiography with re-stenting and intra-aortic balloon pump placement.The VA-ECMO support was complicated by left ventricular distension which we resolved via LAVA-ECMO.Unfortunately,episodes of bleeding and sepsis complicated the clinical picture and the patient passed away 27 d after initiating VA-ECMO.CONCLUSION This clinical case demonstrates that LAVA-ECMO is a viable strategy to unload the LV without another invasive percutaneous or surgical procedure.We also demonstrate that LAVA-ECMO can also be weaned to a left ventricular assist device system.A benefit of this technique is that the procedure is potentially reversible,should the patient require VA-ECMO support again.A transeptal LV venting approach like LAVA-ECMO may be indicated over ImpellaTM in cases where less LV unloading is required and where a restrictive myocardium could cause LV suctioning.Left ventricular over-distention is a well-known complication of peripheral VA-ECMO in cardiogenic shock and LAVA ECMO through transeptal cannulation offers a novel and safe approach for treating LV overloading,without the need of an additional percutaneous access.
基金supported by Youth Project of National Natural Science Foundation of China“The discrete isoperimetric problem of graphs and the study of weierstrass type functions with extremely related conditional connectivity”(12101528)。
文摘The main goal of this paper is to determine the effect of an extra dimension on a traversable wormhole. Here an earlier study by the author [Phys. Rev. D 98, 064041 (2018)] is extended in several significant ways. To begin with, the extra spatial dimension is assumed to be time dependent, while the redshift and shape functions, as well as the extra dimension, are functions of both r and l, the respective radial and extra coordinates;the last of these is therefore a function of r, l, and t. The main objective is to determine the conditions that allow the throat of the wormhole to be threaded with ordinary matter (by respecting the null energy condition) and that the same conditions lead to a violation of the null energy condition in the fifth dimension, which is therefore responsible for sustaining the wormhole. The dependence of the extra dimension on l and t is subject to additional conditions that are subsequently analyzed in this paper. Finally, the extra dimension may be extremely small or even curled up.