背景与目的:大隐静脉高位结扎剥脱术(HSL)是治疗下肢静脉曲张的经典术式,但存在创伤较大、恢复时间较长、切口瘢痕不美观等缺点。随着医疗技术的进步,以腔内热消融治疗为代表的微创治疗技术蓬勃发展。本研究旨在对比射频消融术(RFA)与传...背景与目的:大隐静脉高位结扎剥脱术(HSL)是治疗下肢静脉曲张的经典术式,但存在创伤较大、恢复时间较长、切口瘢痕不美观等缺点。随着医疗技术的进步,以腔内热消融治疗为代表的微创治疗技术蓬勃发展。本研究旨在对比射频消融术(RFA)与传统HSL治疗下肢静脉曲张的临床疗效。方法:回顾性分析2021年5月—2022年6月期间因原发性下肢静脉曲张于首都医科大学附属北京安贞医院血管外科行手术治疗的272例患者(298条肢体)的临床与随访资料,其中96例(100条肢体)行RFA治疗(RFA组),176例(198条肢体)行HSL治疗(HSL组)。比较两组患者的术前临床特征、手术情况、并发症情况、临床表现-病因学-解剖学-病理生理学(CEAP)分级、静脉临床严重程度评分(VCSS)和慢性静脉功能不全问卷-14问版(CIVIQ-14)评分的变化情况。结果:两组技术成功率均为100%,术后3 d复查超声提示大隐静脉主干缺如/闭合率为100%。共完成随访265例(290条肢体),平均随访时间(13.2±3.8)个月,随访期间超声提示大隐静脉主干缺如/闭合率为100%。两组患者的基本临床特征无明显差异(均P>0.05);与HSL组比较,RFA组术中出血量(21.3 mL vs. 46.8 mL)、术后第1天疼痛评分(3.1 vs. 3.3)、总并发症发生率(25.5%vs. 38.0%)及皮肤感觉异常发生率(5.1%vs. 24.0%)均明显降低(均P<0.05),RFA组的深静脉血栓形成发生率升高(5.1%vs. 0,P<0.05);术后所有患者CEAP分级均较术前降级,RFA组81.7%的患肢降级为C0~C1级,HSL组83.9%的患肢降级为C0~C1级;所有患者的VCSS和CIVIQ-14评分均较术前有所改善,且HSL组的VCSS评分改善程度大于RFA组(均P<0.05)。结论:RFA短期疗效与HSL相当,相对于HSL而言,创伤更小、疼痛感更轻、并发症发生率更低,是一种下肢静脉曲张的有效治疗方案。展开更多
This paper proposes a sampling based hierarchical approach for solving the computational demands of the spectral clustering methods when applied to the problem of image segmentation. The authors first define the dista...This paper proposes a sampling based hierarchical approach for solving the computational demands of the spectral clustering methods when applied to the problem of image segmentation. The authors first define the distance between a pixel and a cluster, and then derive a new theorem to estimate the number of samples needed for clustering. Finally, by introducing a scale parameter into the similarity function, a novel spectral clustering based image segmentation method has been developed. An important characteristic of the approach is that in the course of image segmentation one needs not only to tune the scale parameter to merge the small size clusters or split the large size clusters but also take samples from the data set at the different scales. The multiscale and stochastic nature makes it feasible to apply the method to very large grouping problem. In addition, it also makes the segmentation compute in time that is linear in the size of the image. The experimental results on various synthetic and real world images show the effectiveness of the approach.展开更多
Massive amounts of biogas slurry are produced due to the development of biogas plants.The pollution features and the risk of biogas slurry were fully evaluated in this work.Thirty-one biogas slurry samples were collec...Massive amounts of biogas slurry are produced due to the development of biogas plants.The pollution features and the risk of biogas slurry were fully evaluated in this work.Thirty-one biogas slurry samples were collected from sixteen different cities and five different raw materials biogas plants(e.g.cattle manure,swine manure,straw-manure mixture,kitchen waste and chicken manure).The chemical oxygen demand(COD),ammonia nitrogen(NH_(4)^(+)-N),anions(e.g.Cl^(-1),SO_(4)^(2-),NO_(3)^(-)and PO_(4)^(3-)),antibiotics(e.g.sulphonamides,quinolones,β2-receptor agonists,macrolides,tetracyclines and crystal violet)and heavy metals(e.g.Cu,Cd,As,Cr,Hg,Zn and Pb)contents from these biogas slurry samples were systematically investigated.On this basis,risk assessment of biogas slurry was also performed.The concentrations of COD,NH_(4)^(+)-N and PO_(4)^(3-) in biogas slurry samples with chicken manure as raw material were significantly higher than those of other raw materials.Therefore,the biogas slurry from chicken manure raw material demonstrated the most serious eutrophication threat.The antibiotic contents in biogas slurry samples from swine manure were the highest among five raw materials,mostly sulphonamides,quinolones and tetracyclines.Biogas slurry revealed particularly serious arsenic contamination and moderate potential ecological risk.The quadratic polynomial stepwise regression model can quantitatively describe the correlation among NH_(4)^(+)-N,PO_(4)^(3+) and heavy metals concentration of biogas slurry.This work demonstrated a universal potential threat from biogas slurry that can provide supporting data and theoretical basis for harmless treatment and reuse of biogas slurry.展开更多
Lithium sulfur(Li-S)batteries with high specific capacity and energy density can bring enormous opportunities for the nextgeneration energy storage systems.However,the severe dissolution and shuttle effect of lithium ...Lithium sulfur(Li-S)batteries with high specific capacity and energy density can bring enormous opportunities for the nextgeneration energy storage systems.However,the severe dissolution and shuttle effect of lithium polysulfides(LiPSs)is still the key issue that seriously impedes the development of practical Li-S batteries.Here,polar Co9S8 inlaid carbon nanoboxes(Co9S8@C NBs)have been investigated as cathode host for high-performance Li-S batteries.In this integrated structure,Co9S8 nanocrystals not only provide strong chemisorptive capability for polar LiPSs,but also act as a catalyst to accelerate polysulfide redox reactions;while carbon nanobox with large inner space can offer enough space to relieve the volume expansion and physically confine LiPSs’dissolution.As a result,the S/Co9S8@C NBs cathode exhibits high specific capacity at 1C and the capacity retention was^83%after 400 cycles,corresponding to an average decay rate of only^0.043%per cycle.展开更多
文摘背景与目的:大隐静脉高位结扎剥脱术(HSL)是治疗下肢静脉曲张的经典术式,但存在创伤较大、恢复时间较长、切口瘢痕不美观等缺点。随着医疗技术的进步,以腔内热消融治疗为代表的微创治疗技术蓬勃发展。本研究旨在对比射频消融术(RFA)与传统HSL治疗下肢静脉曲张的临床疗效。方法:回顾性分析2021年5月—2022年6月期间因原发性下肢静脉曲张于首都医科大学附属北京安贞医院血管外科行手术治疗的272例患者(298条肢体)的临床与随访资料,其中96例(100条肢体)行RFA治疗(RFA组),176例(198条肢体)行HSL治疗(HSL组)。比较两组患者的术前临床特征、手术情况、并发症情况、临床表现-病因学-解剖学-病理生理学(CEAP)分级、静脉临床严重程度评分(VCSS)和慢性静脉功能不全问卷-14问版(CIVIQ-14)评分的变化情况。结果:两组技术成功率均为100%,术后3 d复查超声提示大隐静脉主干缺如/闭合率为100%。共完成随访265例(290条肢体),平均随访时间(13.2±3.8)个月,随访期间超声提示大隐静脉主干缺如/闭合率为100%。两组患者的基本临床特征无明显差异(均P>0.05);与HSL组比较,RFA组术中出血量(21.3 mL vs. 46.8 mL)、术后第1天疼痛评分(3.1 vs. 3.3)、总并发症发生率(25.5%vs. 38.0%)及皮肤感觉异常发生率(5.1%vs. 24.0%)均明显降低(均P<0.05),RFA组的深静脉血栓形成发生率升高(5.1%vs. 0,P<0.05);术后所有患者CEAP分级均较术前降级,RFA组81.7%的患肢降级为C0~C1级,HSL组83.9%的患肢降级为C0~C1级;所有患者的VCSS和CIVIQ-14评分均较术前有所改善,且HSL组的VCSS评分改善程度大于RFA组(均P<0.05)。结论:RFA短期疗效与HSL相当,相对于HSL而言,创伤更小、疼痛感更轻、并发症发生率更低,是一种下肢静脉曲张的有效治疗方案。
基金National Natural Science Foundation of China (Grant No. 60375003)the Aeronautical Science Foundation of China (Grant No. 03I53059)
文摘This paper proposes a sampling based hierarchical approach for solving the computational demands of the spectral clustering methods when applied to the problem of image segmentation. The authors first define the distance between a pixel and a cluster, and then derive a new theorem to estimate the number of samples needed for clustering. Finally, by introducing a scale parameter into the similarity function, a novel spectral clustering based image segmentation method has been developed. An important characteristic of the approach is that in the course of image segmentation one needs not only to tune the scale parameter to merge the small size clusters or split the large size clusters but also take samples from the data set at the different scales. The multiscale and stochastic nature makes it feasible to apply the method to very large grouping problem. In addition, it also makes the segmentation compute in time that is linear in the size of the image. The experimental results on various synthetic and real world images show the effectiveness of the approach.
基金supported by the National Natural Science Foundation of China(22038012,42077030)the Science and Technology Program of Fujian Province,China(2020NZ012015,2020Y4002)the Fundamental Research Funds for the Central Universities of China(20720190001)。
文摘Massive amounts of biogas slurry are produced due to the development of biogas plants.The pollution features and the risk of biogas slurry were fully evaluated in this work.Thirty-one biogas slurry samples were collected from sixteen different cities and five different raw materials biogas plants(e.g.cattle manure,swine manure,straw-manure mixture,kitchen waste and chicken manure).The chemical oxygen demand(COD),ammonia nitrogen(NH_(4)^(+)-N),anions(e.g.Cl^(-1),SO_(4)^(2-),NO_(3)^(-)and PO_(4)^(3-)),antibiotics(e.g.sulphonamides,quinolones,β2-receptor agonists,macrolides,tetracyclines and crystal violet)and heavy metals(e.g.Cu,Cd,As,Cr,Hg,Zn and Pb)contents from these biogas slurry samples were systematically investigated.On this basis,risk assessment of biogas slurry was also performed.The concentrations of COD,NH_(4)^(+)-N and PO_(4)^(3-) in biogas slurry samples with chicken manure as raw material were significantly higher than those of other raw materials.Therefore,the biogas slurry from chicken manure raw material demonstrated the most serious eutrophication threat.The antibiotic contents in biogas slurry samples from swine manure were the highest among five raw materials,mostly sulphonamides,quinolones and tetracyclines.Biogas slurry revealed particularly serious arsenic contamination and moderate potential ecological risk.The quadratic polynomial stepwise regression model can quantitatively describe the correlation among NH_(4)^(+)-N,PO_(4)^(3+) and heavy metals concentration of biogas slurry.This work demonstrated a universal potential threat from biogas slurry that can provide supporting data and theoretical basis for harmless treatment and reuse of biogas slurry.
基金The authors acknowledge the financial support from the National Postdoctoral Program for Innovation Talents(No.BX201700103)China Postdoctoral Science Foundation funded project(No.2018M633664).
文摘Lithium sulfur(Li-S)batteries with high specific capacity and energy density can bring enormous opportunities for the nextgeneration energy storage systems.However,the severe dissolution and shuttle effect of lithium polysulfides(LiPSs)is still the key issue that seriously impedes the development of practical Li-S batteries.Here,polar Co9S8 inlaid carbon nanoboxes(Co9S8@C NBs)have been investigated as cathode host for high-performance Li-S batteries.In this integrated structure,Co9S8 nanocrystals not only provide strong chemisorptive capability for polar LiPSs,but also act as a catalyst to accelerate polysulfide redox reactions;while carbon nanobox with large inner space can offer enough space to relieve the volume expansion and physically confine LiPSs’dissolution.As a result,the S/Co9S8@C NBs cathode exhibits high specific capacity at 1C and the capacity retention was^83%after 400 cycles,corresponding to an average decay rate of only^0.043%per cycle.
