期刊文献+
共找到1,334篇文章
< 1 2 67 >
每页显示 20 50 100
Further study on the genesis of lamellar calcite veins in lacustrine black shale--A case study of Paleogene in Dongying Depression, China
1
作者 Guan-Min Wang Yun-Jiao Zhang +3 位作者 Zi-Yuan Yin Rui Zhu Zhi-Yao Hou Yu Bai 《Petroleum Science》 SCIE EI CAS CSCD 2024年第3期1508-1523,共16页
Lamellar calcite veins are prevalent in carbonate-rich,lacustrine dark shale.The formation mechanisms of these veins have been extensively debated,focusing on factors such as timing,depth,material source,and driving f... Lamellar calcite veins are prevalent in carbonate-rich,lacustrine dark shale.The formation mechanisms of these veins have been extensively debated,focusing on factors such as timing,depth,material source,and driving forces.This paper examines dark lacustrine shale lamellar calcite veins in the Paleogene strata of Dongying Depression,using various analytical techniques:petrography,isotope geochemistry,cathodoluminescence,inclusion thermometry,and electron probe micro-analysis.Two distinct types of calcite veins have been identified:granular calcite veins and sparry calcite veins.These two types differ significantly in color,grain structure,morphology,and inclusions.Through further investigation,it was observed that vein generation occurred from the shallow burial period to the maturation of organic matter,with a transition from granular calcite veins to sparry calcite veins.The granular calcite veins exhibit characteristics associated with the shallow burial period,including plastically deformed laminae and veins,the development of strawberry pyrite,the absence of oil and gas,weak fractionation in oxygen isotopes,and their contact relationship with sparry calcite veins.These granular calcite veins were likely influenced by the reduction of sulfate bacteria.On the other hand,sparry calcite veins with fibrous grains are antitaxial and closely linked to the evolution and maturation of organic matter.They contain oil and gas inclusions and show a distribution range of homogenization temperature between 90℃ and 120℃ and strong fractionation in oxygen isotopes,indicating formation during the hydrocarbon expulsion period.The carbon isotope analysis of the surrounding rocks and veins suggests that the material for vein formation originates from the shale itself,specifically authigenic micritic calcite modified by the action of methanogens.The opening of horizontal fractures and vein formation is likely driven by fluid overpressure resulting from undercompaction and hydrocarbon expulsion.Veins may form rapidly or through multi-stage composite processes.Early veins are predominantly formed in situ,while late veins are a result of continuous fluid migration and convergence.Furthermore,the veins continue to undergo modification even after formation.This study emphasizes that the formation of lamellar calcite veins in shale is a complex diagenetic process influenced by multiple factors:biology,organic matter,and inorganic processes,all operating at various stages throughout the shale's diagenetic history. 展开更多
关键词 Calcite veins Shale diagenesis Material source Formation period Formation mechanism
下载PDF
Sclerotherapy as the Only Treatment for Varicose Veins
2
作者 Moaath Al-Smady Qutaiba AbuQuba +4 位作者 Ahmad Al-Saraheen Basil Al-Azaideh Malik Allahham Zeenah Alsmady Amjad Bani Hani 《World Journal of Cardiovascular Surgery》 2024年第10期166-180,共15页
Background: Chronic venous insufficiency (CVI) is a widespread and underdiagnosed condition that affects more than 20% of the general population. The most prevalent manifestation of CVI is varicose veins (VVs), which ... Background: Chronic venous insufficiency (CVI) is a widespread and underdiagnosed condition that affects more than 20% of the general population. The most prevalent manifestation of CVI is varicose veins (VVs), which affect up to 25% of women and 15% of males. Sclerotherapy is a minimally invasive procedure used primarily in treating telangiectasias, reticular veins, and small varicose veins. Objectives: This study aims to evaluate the efficacy and safety of various sclerotherapy techniques in treating varicose veins-related complications. Methods: We conducted a cross-sectional observational interventional study at Jordan University Hospital (JUH) from September 2022 to January 2023. The study involved patients with lower limb varicose veins, assessing their clinical response and monitoring potential treatment complications. Statistical analyses were performed using SPSS software version 21.0. Results: Of 567 patients with diagnosed VVs, 544 were female (95.94%), and 23 were male (4.06%). The primary complaints were pain and cosmetic concerns. Treatments included Foam Aethoxysklerol® 3% (polidocanol) and Micro-foam Aethoxysklerol® 1%. Improvement in symptoms was reported by 538 patients (94.89%). The most common adverse event was hyperpigmentation, reported in 120 patients (21.16%), followed by post-procedural pain in 104 patients (18.34%). Notably, one patient (0.18%) experienced deep vein thrombosis (DVT), one (0.18%) reported telangiectatic matting, and there were two cases (0.36%) of visual disturbances and one allergic reaction. Conclusion: Sclerotherapy is effective and safe for treating VVs with minimal adverse events. It is a viable standalone treatment, reducing complications linked to other methods like radiofrequency ablation and surgery. 展开更多
关键词 Chronic Venous Insufficiency Foam Sclerotherapy Varicose veins Adverse Events
下载PDF
Geology and Geochemistry of K-feldspar Veins in Lamprophyre at the Zhenyuan Gold Deposit,Yunnan,Southwest China:Implications for Gold Mineralization
3
作者 ZHANG Huichao CHAI Peng +2 位作者 ZHANG Hongrui ZHOU Limin HOU Zengqian 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第1期104-116,共13页
Lamprophyres typically appear in hydrothermal gold deposits.The relationship between lamprophyres and gold deposits is investigated widely.Some researchers suggest that the emplacement of lamprophyres triggers gold mi... Lamprophyres typically appear in hydrothermal gold deposits.The relationship between lamprophyres and gold deposits is investigated widely.Some researchers suggest that the emplacement of lamprophyres triggers gold mineralization,whereas others hypothesize that the formation of lamprophyres increases the fertility of mantle sources and ore-forming fluids.K-feldspar veins,with ages between those of lamprophyres and gold deposits,appear in lamprophyres in Zhenyuan.Therefore,K-feldspar veins are ideal for investigating the relationship between lamprophyres and gold deposits.Phlogopite in K-feldspar veins has lower Mg#,Ni,and Cr contents and higher TiO2,Li,Ba,Sr,Sc,Zr,Nb,and Cs contents than phlogopite in lamprophyres.The in-situ Sr isotopic values of apatites(0.7063–0.7066)in K-feldspar veins are within the range for apatites(0.7064–0.7078)from lamprophyres.High large-ion lithophile element concentrations and low Nb and Ta concentrations in phlogopite from lamprophyres,in addition to high(87Sr/86Sr)i values of apatite(0.7064–0.7078),indicate that the magma parental to these phlogopite and apatite crystals is derived from an enriched mantle.Kfeldspar veins are genetically correlated with lamprophyres,whereas sulfide mineral assemblage and trace element compositions of pyrite in K-feldspar veins suggest that K-feldspar veins in lamprophyres are not directly related to gold mineralization of the Zhenyuan deposit. 展开更多
关键词 LAMPROPHYRE K-feldspar vein apatite Sr isotope gold Zhenyuan deposit YUNNAN
下载PDF
Benefit in physical function and quality of life to nonsurgical treatment of varicose veins: Pilot study
4
作者 Gwon-Min Kim BoKun Kim +5 位作者 Minwoo Jang Jong-Hwan Park Miju Bae Chung Won Lee Jong Won Kim Up Huh 《World Journal of Clinical Cases》 SCIE 2024年第3期517-524,共8页
BACKGROUND Studies on varicose veins have focused its effects on physical function;however,whether nonsurgical treatments alter muscle oxygenation or physical function remains unclear.Moreover,the differences in such ... BACKGROUND Studies on varicose veins have focused its effects on physical function;however,whether nonsurgical treatments alter muscle oxygenation or physical function remains unclear.Moreover,the differences in such functions between individuals with varicose veins and healthy individuals remain unclear.AIM To investigate changes in physical function and the quality of life(QOL)following nonsurgical treatment of patients with varicose veins and determine the changes in their muscle oxygenation during activity.METHODS We enrolled 37 participants(those with varicose veins,n=17;healthy individuals,n=20).We performed the following measurements pre-and post-nonsurgical treatment in the varicose vein patients and healthy individuals:Calf muscle oxygenation during the two-minute step test,open eyes one-leg stance,30 s sit-to-stand test,visual analog scale(VAS)for pain,Pittsburgh sleep quality index,physical activity assessment,and QOL assessment.RESULTS Varicose veins patients and healthy individuals differ in most variables(physical function,sleep quality,and QOL).Varicose veins patients showed significant differences between pre-and post-nonsurgical treatment—results in the 30 sit-to-stand test[14.41(2.45)to 16.35(4.11),P=0.018],two-minute step test[162.29(25.98)to 170.65(23.80),P=0.037],VAS for pain[5.35(1.90)to 3.88(1.73),P=0.004],and QOL[39.34(19.98)to 26.69(17.02),P=0.005];however,no significant difference was observed for muscle oxygenation.CONCLUSION Nonsurgical treatment improved lower extremity function and QOL in varicose veins patients,bringing their condition close to that of healthy individuals.Future studies should include patients with severe varicose veins requiring surgery to confirm our findings. 展开更多
关键词 Varicose vein Nonsurgical treatment Physical function Quality of life Near infrared spectroscopy
下载PDF
Multidetector computer tomography and magnetic resonance imaging of double superior mesenteric veins:A case report
5
作者 Wei Tang Song Peng 《World Journal of Clinical Cases》 SCIE 2024年第17期3265-3270,共6页
BACKGROUND This study aimed to describe the findings of double superior mesenteric veins(SMVs),a rare anatomical variation,on multidetector computer tomography(MDCT)and magnetic resonance imaging(MRI)images.CASE SUMMA... BACKGROUND This study aimed to describe the findings of double superior mesenteric veins(SMVs),a rare anatomical variation,on multidetector computer tomography(MDCT)and magnetic resonance imaging(MRI)images.CASE SUMMARY We describe the case of a 34-year-old male,who underwent both MDC and MRI examinations of the upper abdomen because of liver cirrhosis.MDCT and MRI angiography images of the upper abdomen revealed an anatomic variation of the superior mesenteric vein(SMV),the double SMVs.CONCLUSION The double SMVs are a congenital abnormality without potential clinical manifestation.Physicians need to be aware of this anatomical variation during abdominal surgery to avoid iatrogenic injury. 展开更多
关键词 Superior mesenteric vein Anatomic variation Magnetic resonance imaging Multidetector computer tomography Case report
下载PDF
Modeling Blood Flow in Veins of Uniform Properties (Giraffe Jugular Vein)
6
作者 Rogers Omboga Amenya Johanna Kibet Sigey +1 位作者 Geoffrey Moriaso Ole Maloiy David Mwangi Theuri 《Open Journal of Biophysics》 2024年第2期132-153,共22页
This paper models the giraffe’s jugular veins as a uniform collapsible tube from a rigid skull. The equations governing one-dimensional steady flow through such a tube for various conditions have been developed. The ... This paper models the giraffe’s jugular veins as a uniform collapsible tube from a rigid skull. The equations governing one-dimensional steady flow through such a tube for various conditions have been developed. The effects of inertial and inclination angles that have not been discussed previously have been included. It has been shown that different flows for a uniform tube (vein) are possible. However, this flow matches that of a jugular vein which is supercritical, and the steady solution has been given by the balance between the driving forces of gravity and the viscous resistance to the flow at the right atrium of the heart must be sub-critical for a fixed right-atrium pressure which means that an elastic jump is required to return the flow to sub-critical from the supercritical flow upstream this type of relationship gives rise to flow limitation at the same time given any right atrium fixed pressure there exists a maximum flow rate which when exceeded the boundary conditions of the flow do not hold boundary conditions at the right atrium are not satisfied hence making the steady flow impossible this mechanism of flow limitation is slightly different from the other one in that causes airways through forced expiration from the observation made it is clearly shown that there is an intravascular pressure difference with a change in height. 展开更多
关键词 Blood Flow Jugular Vein Cross-Sectional Area SUPERCRITICAL SUBCRITICAL JUMP
下载PDF
Automatic Detection and Characterization of Human Veins Using Infra-Red Image Processing
7
作者 Jean Ndoumbe Brice Ekobo Akoa +3 位作者 Gaelle Patricia Talotsing Frederic Franck Kounga Samuel Kaissassou Bertin Chouanmo Njo 《Journal of Computer and Communications》 2024年第9期141-159,共19页
The detection and characterization of human veins using infrared (IR) image processing have gained significant attention due to its potential applications in biometric identification, medical diagnostics, and vein-bas... The detection and characterization of human veins using infrared (IR) image processing have gained significant attention due to its potential applications in biometric identification, medical diagnostics, and vein-based authentication systems. This paper presents a low-cost approach for automatic detection and characterization of human veins from IR images. The proposed method uses image processing techniques including segmentation, feature extraction, and, pattern recognition algorithms. Initially, the IR images are preprocessed to enhance vein structures and reduce noise. Subsequently, a CLAHE algorithm is employed to extract vein regions based on their unique IR absorption properties. Features such as vein thickness, orientation, and branching patterns are extracted using mathematical morphology and directional filters. Finally, a classification framework is implemented to categorize veins and distinguish them from surrounding tissues or artifacts. A setup based on Raspberry Pi was used. Experimental results of IR images demonstrate the effectiveness and robustness of the proposed approach in accurately detecting and characterizing human. The developed system shows promising for integration into applications requiring reliable and secure identification based on vein patterns. Our work provides an effective and low-cost solution for nursing staff in low and middle-income countries to perform a safe and accurate venipuncture. 展开更多
关键词 Vein Detection Blood Radiation Infrared Image CLAHE Algorithm Raspberry Pi
下载PDF
In vivo quantification of human aqueous veins by enhanced depth imaging optical coherence tomography and optical coherence tomography angiography images 被引量:1
8
作者 Zhi-Qi Chen Wei Chen +3 位作者 Chao-Hua Deng Jing-Min Guo Hong Zhang Jun-Ming Wang 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2023年第9期1482-1488,共7页
AIM:To investigate the aqueous vein in vivo by using enhanced depth imaging optical coherence tomography(EDI-OCT)and optical coherence tomography angiography(OCTA).METHODS:In this cross-sectional comparative study,30 ... AIM:To investigate the aqueous vein in vivo by using enhanced depth imaging optical coherence tomography(EDI-OCT)and optical coherence tomography angiography(OCTA).METHODS:In this cross-sectional comparative study,30 healthy participants were enrolled.Images of the aqueous and conjunctival veins were captured by EDI-OCT and OCTA before and after water loading.The area,height,width,location depth and blood flow of the aqueous vein and conjunctival vein were measured by Image J software.RESULTS:In the static state,the area of the aqueous vein was 8166.7±3272.7μm^(2),which was smaller than that of the conjunctival vein(13690±7457μm^(2),P<0.001).The mean blood flow density of the aqueous vein was 35.3%±12.6%,which was significantly less than that of the conjunctival vein(51.5%±10.6%,P<0.001).After water loading,the area of the aqueous vein decreased significantly from 8725.8±779.4μm^(2)(baseline)to 7005.2±566.2μm^(2)at 45min but rose to 7863.0±703.2μm^(2)at 60min(P=0.032).The blood flow density of the aqueous vein decreased significantly from 41.2%±4.5%(baseline)to 35.4%±3.2%at 30min but returned to 45.6%±3.6%at 60min(P=0.021).CONCLUSION:The structure and blood flow density of the aqueous vein can be effectively evaluated by OCT and OCTA.These may become biological indicators to evaluate aqueous vein changes and aqueous outflow resistance under different interventions in glaucoma patients. 展开更多
关键词 aqueous vein optical coherence tomography optical coherence tomography angiography water drinking test
下载PDF
Phlebosclerosis: An overlooked complication of varicose veins that affects clinical outcome: A case report
9
作者 Shi-Yan Ren Song-Yi Qian Rong-Ding Gao 《World Journal of Clinical Cases》 SCIE 2023年第35期8404-8410,共7页
BACKGROUND Phlebosclerosis is a common age-related fibrotic degeneration of the venous wall.It is a disorder rather than a disease,which may cause venous dysfunction and even venous thrombosis.It is rarely reported in... BACKGROUND Phlebosclerosis is a common age-related fibrotic degeneration of the venous wall.It is a disorder rather than a disease,which may cause venous dysfunction and even venous thrombosis.It is rarely reported in patients with varicose veins.CASE SUMMARY The present report describes the case of a 70-year-old man with varicose veins,vitiligo,and phlebosclerosis.Venous angiography revealed blood reflux in the superficial and deep veins.The patient underwent surgery to remove the saphe-nous veins.During the operation,a calcified vein resembling a wooden stick was found,which was surprisingly extracted from the thickened venous wall.A cross-section of this wooden stick-like vein revealed venous fibrosis and calcification,obvious thickening of the venous wall,extensive collagen deposition on the venous wall,hyaline degeneration,and venous sclerosis causing closure of the venous lumen.CONCLUSION This is probably the first report of a wooden stick-like structure being found in the venous wall in patients with varicose veins and venous ulcers.Phlebosclerosis can be observed in the late stage of varicose veins complicated by frequent infections and worse clinical outcomes.Therefore,it is important to be aware of this condition and address it rather than overlook it. 展开更多
关键词 Phlebosclerosis Varicose vein Phlebothrombosis THROMBOPHLEBITIS CALCIFICATION Ossification of vein wall Chronic venous disease Case report
下载PDF
Enlightenment of calcite veins in deep Ordovician Wufeng-Silurian Longmaxi shales fractures to migration and enrichment of shale gas in southern Sichuan Basin, SW China
10
作者 CUI Yue LI Xizhe +5 位作者 GUO Wei LIN Wei HU Yong HAN Lingling QIAN Chao ZHAO Jianming 《Petroleum Exploration and Development》 SCIE 2023年第6期1374-1385,共12页
The relationship between fracture calcite veins and shale gas enrichment in the deep Ordovician Wufeng Formation-Silurian Longmaxi Formation (Wufeng-Longmaxi) shales in southern Sichuan Basin was investigated through ... The relationship between fracture calcite veins and shale gas enrichment in the deep Ordovician Wufeng Formation-Silurian Longmaxi Formation (Wufeng-Longmaxi) shales in southern Sichuan Basin was investigated through core and thin section observations, cathodoluminescence analysis, isotopic geochemistry analysis, fluid inclusion testing, and basin simulation. Tectonic fracture calcite veins mainly in the undulating part of the structure and non-tectonic fracture calcite veins are mainly formed in the gentle part of the structure. The latter, mainly induced by hydrocarbon generation, occurred at the stage of peak oil and gas generation, while the former turned up with the formation of Luzhou paleouplift during the Indosinian. Under the influence of hydrocarbon generation pressurization process, fractures were opened and closed frequently, and oil and gas episodic activities are recorded by veins. The formation pressure coefficient at the maximum paleodepth exceeds 2.0. The formation uplift stage after the Late Yanshanian is the key period for shale gas migration. Shale gas migrates along the bedding to the high part of the structure. The greater the structural fluctuation is, the more intense the shale gas migration activity is, and the loss is more. The gentler the formation is, the weaker the shale gas migration activity is, and the loss is less. The shale gas enrichment in the core of gentle anticlines and gentle synclines is relatively higher. 展开更多
关键词 Sichuan Basin deep formation in southern Sichuan Basin Ordovician Wufeng Formation Silurian Longmaxi Formation fracture calcite vein fluid inclusion shale gas enrichment model
下载PDF
基于Veins的交通路径优化算法研究
11
作者 刘琨 《信息技术》 2022年第5期118-122,127,共6页
智能交通系统是未来智慧城市中不可缺少的一部分,而交通路径优化是智能交通重要的组成部分。文中主要研究了在Veins平台中交通路径优化算法。通过VANET(车载自组网)每台车辆都在同一个局域网互连互通,当前车遇到拥堵时通过拥塞躲避机制... 智能交通系统是未来智慧城市中不可缺少的一部分,而交通路径优化是智能交通重要的组成部分。文中主要研究了在Veins平台中交通路径优化算法。通过VANET(车载自组网)每台车辆都在同一个局域网互连互通,当前车遇到拥堵时通过拥塞躲避机制不断通知后方车辆,后方车辆通过设计的路径规划算法进行路径变更,直至拥堵结束。通过分析车辆通过的情况和交通数据,不断优化算法,最终达到减缓拥堵和提高交通效率的目的。 展开更多
关键词 veins 路径规划 拥塞躲避 优化算法 交通优化
下载PDF
Construction of Anti-breaking Models of the Main Veins of Flue-cured Tobacco Leaves and Principal Component Analysis 被引量:4
12
作者 王宝玉 孙婷婷 +3 位作者 章国顺 张蜀香 阮龙 张云华 《Agricultural Science & Technology》 CAS 2011年第11期1615-1616,1656,共3页
[Objective] This study aimed to explore the related mechanisms of the breaking of flue-cured tobacco leaves. [Method] Anti-breaking models of the main veins of flue-cured tobacco leaves were constructed for principal ... [Objective] This study aimed to explore the related mechanisms of the breaking of flue-cured tobacco leaves. [Method] Anti-breaking models of the main veins of flue-cured tobacco leaves were constructed for principal component analysis on the anti-breaking index, leaf traits and cellulose contents. [Result] The results showed that the growth traits had certain relevance with the cellulose contents while the leaf weight assumed a significant negative correlation with the anti-breaking index, indicating that the heavier the leaf weight was, the weaker the anti-breaking capacity of flue-cured tobacco would be; the cross-sectional area of main veins and the cellulose contents had shown a positive correlation with the anti-breaking index, indicating that the thicker the main vein of flue-cured tobacco was, the higher the cellulose contents would be, and the stronger the anti-breaking capacity of flue-cured tobacco leaves would be. [Conclusion] This study provided theoretical basis and reference to improve tobacco production and enhance the quality of flue-cured tobacco. 展开更多
关键词 Flue-cured tobacco Main vein Anti-breaking index Principal component analysis
下载PDF
基于Veins平台的交通信号灯智能控制仿真研究 被引量:1
13
作者 王晓萌 刘松云 +1 位作者 李鑫 曹英晖 《信息通信》 2016年第10期61-62,共2页
智能交通系统是即将到来的物联网时代中"智慧城市"必不可少的一环。笔者研究了现今应用较广泛的交通灯控制算法,如固定配时控制算法、全感应式控制算法、半感应控制算法,并分析了它们的优缺点。在此基础上提出了感应式综合控... 智能交通系统是即将到来的物联网时代中"智慧城市"必不可少的一环。笔者研究了现今应用较广泛的交通灯控制算法,如固定配时控制算法、全感应式控制算法、半感应控制算法,并分析了它们的优缺点。在此基础上提出了感应式综合控制算法,并在Veins仿真环境下,把这四种控制算法做比较,发现感应式综合控制算法控制效果良好。这就为改善交通拥堵、道路堵塞、信号灯不可智能控制等问题提供一个相对可行的解决方案。仿真研究(智能交通系统),成本小,安全方便,已成为研究室中越来越受欢迎的研究手段。 展开更多
关键词 veins平台 交通信号灯智能控制 交通信号灯智能控制算法 仿真
下载PDF
Strategies and challenges in treatment of varicose veins and venous insufficiency 被引量:12
14
作者 Rong-Ding Gao Song-Yi Qian +2 位作者 Hai-Hong Wang Yong-Sheng Liu Shi-Yan Ren 《World Journal of Clinical Cases》 SCIE 2022年第18期5946-5956,共11页
Patients with varicose veins can be treated with conservative or surgical approaches based on the clinical conditions and patient preferences.In the recent decade,the recommendations for managing symptomatic varicose ... Patients with varicose veins can be treated with conservative or surgical approaches based on the clinical conditions and patient preferences.In the recent decade,the recommendations for managing symptomatic varicose veins have changed dramatically due to the rise of minimally invasive endovascular techniques.The literature was systematically searched on Medline without language restrictions.All papers on the treatment of varicose veins and venous insufficiency with different procedures were included and reviewed.Endovenous laser ablation(EVLA)and radiofrequency ablation(RFA)both are same safe and effective in terms of occlusion rate,and time to return to normal activity.In comparison with RFA or EVLT,Cure conservatrice et Hemodynamique de l’Insufficience Veineuse en Ambulatoire(CHIVA)may cause more bruising and make little or no difference to rates of limb infection,superficial vein thrombosis,nerve injury,or hematoma.In terms of recurrence of varicose veins,there is little or no difference between CHIVA and stripping,RFA,or EVLT.Great saphenous vein recanalization is highest in the ultrasound-guided foam sclerotherapy(FS)group(51%)during 1 year of follow-up.The 2013 National Institute for Health and Care Excellence clinical guidelines recommend surgery as a third-line therapeutic option after EVLA or RFA and sclerotherapy.Although the mechanochemical endovenous ablation(MOCA)is a non-thermal,non-tumescent option and appears to be of similar efficacy to stab avulsion with no potential risk of nerve damage,the overall success rate of MOCA is lower than those of other procedures such as EVLA,RFA,or high ligation and stripping.EVLA is the most cost-effective therapeutic option,with RFA being a close second for the treatment of patients with varicose veins.Endovenous thermal ablation(EVLA or RFA)is recommended as a first-line treatment for varicose veins and has substituted the high ligation of saphenofemoral junctional reflux and stripping of varicose veins.Ultrasound-guided FS is associated with a high recurrence rate and can be used in conjunction with other procedures.MOCA and cyanoacrylate embolization appear promising,but evidence of their effectiveness is required. 展开更多
关键词 Varicose veins Venous insufficiency High ligation and stripping Endovenous laser ablation Radiofrequency ablation Cure conservatrice et Hemodynamique de l’Insufficience Veineuse en Ambulatoire
下载PDF
Subduction channel fluid-rock interaction:Indications from rutile-quartz veins within eclogite from the Yuka terrane,North Qaidam orogen 被引量:4
15
作者 Xin Chen Youye Zheng +5 位作者 Rongke Xu Pingyang Gu Jiyuan Yu Jie Bai Pengjie Cai Xiaojia Jiang 《Geoscience Frontiers》 SCIE CAS CSCD 2020年第2期635-650,共16页
High-pressure(HP)or ultrahigh-pressure(UHP)rutile-quartz veins that form at mantle depths due to fluid-rock interaction can be used to trace the properties and behavior of natural fluids in subduction zones.To explore... High-pressure(HP)or ultrahigh-pressure(UHP)rutile-quartz veins that form at mantle depths due to fluid-rock interaction can be used to trace the properties and behavior of natural fluids in subduction zones.To explore the fluid flow and the associated element mobility during deep subduction and exhumation of the continental crust,we investigated the major and trace elements of Ti-rich minerals.Additionally,U–Pb dating,trace element contents,and Lu–Hf isotopic composition of zircon grains in the UHP eclogite and associated rutile-quartz veins were examined in the North Qaidam UHP metamorphic belt,Yuka terrane.The zircon grains in the rutile-quartz veins have unzoned or weak oscillatory zonings,and show low Th/U ratios,steep chondrite-normalized patterns of heavy rare earth elements(HREEs),and insignificant negative Eu anomalies,indicating their growth in metamorphic fluids.These zircon grains formed in 4313 Ma,which is consistent with the 4322 Ma age of the host eclogite.As for the zircons in the rutile-quartz veins,they showed steep HREE patterns on one hand,and were different from the zircons present in the host eclogite on the other.This demonstrates that their formation might have been related to the breakdown of the early stage of garnet,which corresponds to the abundance of fluids during the early exhumation stage.The core-rim profile analyses of rutile recorded a two-stage rutile growth across a large rutile grain;the rutile core has higher Nb,Ta,W,and Zr contents and lower Nb/Ta ratios than the rim,indicating that the rutile domains grew in different metamorphic fluids from the core towards the rim.The significant enrichment of high field strength elements(HFSEs)in the rutile core suggests that the peak fluids have high solubility and transportation capacity of these HFSEs.Furthermore,variations in the Nb vs.Cr trends in rutile indicate a connection of rutile to mafic protolith.The zircon grains from both the rutile-quartz veins and the host eclogite have similar Hf isotopic compositions,indicating that the vein-forming fluids are internally derived from the host eclogite.These fluids accumulated in the subduction channel and were triggered by local dehydration of the deeply subducted eclogite during the early exhumation conditions. 展开更多
关键词 Quartz-rutile veins ECLOGITE Fluid-rock interaction Fluid flow Yuka North Qaidam
下载PDF
Quantifying the carbon source of pedogenic calcite veins in weathered limestone: implications for the terrestrial carbon cycle 被引量:3
16
作者 Lin Zou Lin Dong +5 位作者 Meng Ning Kangjun Huang Yongbo Peng Shujian Qin Honglin Yuan Bing Shen 《Acta Geochimica》 EI CAS CSCD 2019年第4期481-496,共16页
The continent is the second largest carbon sink on Earth’s surface.With the diversification of vascular land plants in the late Paleozoic,terrestrial organic carbon burial is represented by massive coal formation,whi... The continent is the second largest carbon sink on Earth’s surface.With the diversification of vascular land plants in the late Paleozoic,terrestrial organic carbon burial is represented by massive coal formation,while the development of soil profiles would account for both organic and inorganic carbon burial.As compared with soil organic carbon,inorganic carbon burial,collectively known as the soil carbonate,would have a greater impact on the long-term carbon cycle.Soil carbonate would have multiple carbon sources,including dissolution of host calcareous rocks,dissolved inorganic carbon from freshwater,and oxidation of organic matter,but the host calcareous rock dissolution would not cause atmospheric CO2drawdown.Thus,to evaluate the potential effect of soil carbonate formation on the atmospheric p CO2level,different carbon sources of soil carbonate should be quantitatively differentiated.In this study,we analyzed the carbon and magnesium isotopes of pedogenic calcite veins developed in a heavily weathered outcrop,consisting of limestone of the early Paleogene Guanzhuang Group in North China.Based on the C and Mg isotope data,we developed a numerical model to quantify the carbon source of calcite veins.The modeling results indicate that4–37 wt%of carbon in these calcite veins was derived from atmospheric CO2.The low contribution from atmospheric CO2might be attributed to the host limestone that might have diluted the atmospheric CO2sink.Nevertheless,taking this value into consideration,it is estimated that soil carbonate formation would lower 1 ppm atmospheric CO2within 2000 years,i.e.,soil carbonate alone would sequester all atmospheric CO2within 1 million years.Finally,our study suggests the C–Mg isotope system might be a better tool in quantifying the carbon source of soil carbonate. 展开更多
关键词 Mg isotope CALCITE veins Pedogenic CARBONATE SILICATE WEATHERING CARBONATE WEATHERING
下载PDF
Application of the Trivex system in the treatment of primary severe superficial varicose veins of the lower extremity 被引量:6
17
作者 Wenshui Yu Jing Liu +4 位作者 Hongwei Yang Zuhui Wang Yongdi Xia Peijuan Liu Guoxian Zhu 《Journal of Interventional Medicine》 2019年第4期146-149,共4页
Purpose:The aim of this study was to evaluate the clinical effects of the Trivex system in the treatment of primary severe superficial varicose veins of the lower extremity and compare Trivex to the point-form-strippi... Purpose:The aim of this study was to evaluate the clinical effects of the Trivex system in the treatment of primary severe superficial varicose veins of the lower extremity and compare Trivex to the point-form-stripping combined with foam sclerotherapy(FS).Methods:A total of 64 patients(35 females,29 males;mean age,57?11 years[range,29–79 years])with primary severe superficial varicose veins of the lower extremity involving 64 legs were included between October 2015 and July 2019.The maximum diameter of the vein branches was>20 mm,which appeared to be cystic dilatation and forms large-scale in the crus or the thigh.All patients underwent high ligation and endovenous laser ablation or stripping of the trunk under general anesthesia.The surgical time,pain/phlebitis,number of incisions,amount of bleeding,recurrence of varicose vein,incidence of surgical site infections(SSIs),satisfaction score,and improvement in clinical symptoms were evaluated respectively with the patients in two groups:Group A,with patients who underwent treatment with the Trivex system,and Group B,patients who underwent treatment by point-form-stripping combined with FS.Results:All procedures were performed successfully.The average operative time in Group A was 56?11 min,whereas that of Group B was 90?33 min,which was a significant difference(p<0.05).Group A patients felt little pain after surgery,whereas in Group B the level of pain peaked on postoperative day 30,mostly due to thrombophlebitis after FS.There was no recurrence of varicose vein was observed in any patient,however,there were some residual effects in Group B,including the amount of bleeding volume,in-hospital stays,pain/phlebitis,and number of incisions(P<0.05).There were no significant differences with respect to SSIs,improvement in clinical symptoms,and satisfaction scores observed(p>0.05).Conclusions:This study shows that patients benefited from both treatment options.However,primary severe superficial varicose veins of the lower extremity treated with the Trivex system suffered less pain with fewer incisions than severe branches treated with the point-form-stripping combined with foam sclerotherapy(FS).In summary,the Trivex system is a suitable treatment prior to point-form-stripping combined with foam sclerotherapy(FS)for those who demand a high level of appearance,and especially for young patients,the Trivex system is recommended. 展开更多
关键词 VARICOSE veins TRIVEX SYSTEM Point-form-stripping Foam SCLEROTHERAPY
下载PDF
Understanding Contaminant Veins in Squeeze Casting and Semi-solid Metalworking Processes 被引量:3
18
作者 Edward J. Vinarcik, P.E. 《特种铸造及有色合金》 CAS CSCD 北大核心 2003年第z1期230-234,238,共6页
关键词 CONTAMINANT veins SQUEEZE CASTING SEMI-SOLID CASTING
下载PDF
OBV(obscure vein),a C_(2)H_(2)zinc finger transcription factor,positively regulates chloroplast development and bundle sheath extension formation in tomato(Solanum lycopersicum)leaf veins 被引量:2
19
作者 Jinghua Lu Chunyang Pan +13 位作者 Xin Li Zejun Huang Jinshuai Shu Xiaoxuan Wang Xiaoxiao Lu Feng Pan Junling Hu Hui Zhang Wenyue Su Min Zhang Yongchen Du Lei Liu Yanmei Guo Junming Li 《Horticulture Research》 SCIE 2021年第1期3228-3241,共14页
Leaf veins play an important role in plant growth and development,and the bundle sheath(BS)is believed to greatly improve the photosynthetic efficiency of C_(4) plants.The OBV mutation in tomato(Solanum lycopersicum)r... Leaf veins play an important role in plant growth and development,and the bundle sheath(BS)is believed to greatly improve the photosynthetic efficiency of C_(4) plants.The OBV mutation in tomato(Solanum lycopersicum)results in dark veins and has been used widely in processing tomato varieties.However,physiological performance has difficulty explaining fitness in production.In this study,we confirmed that this mutation was caused by both the increased chlorophyll content and the absence of bundle sheath extension(BSE)in the veins.Using genome-wide association analysis and map-based cloning,we revealed that OBV encoded a C_(2)H_(2) L domain class transcription factor.It was localized in the nucleus and presented cell type-specific gene expression in the leaf veins.Furthermore,we verified the gene function by generating CRISPR/Cas9 knockout and overexpression mutants of the tomato gene.RNA sequencing analysis revealed that OBV was involved in regulating chloroplast development and photosynthesis,which greatly supported the change in chlorophyll content by mutation.Taken together,these findings demonstrated that OBV affected the growth and development of tomato by regulating chloroplast development in leaf veins.This study also provides a solid foundation to further decipher the mechanism of BSEs and to understand the evolution of photosynthesis in land plants. 展开更多
关键词 EXTENSION (2) veins
下载PDF
Discovery of the pegmatite lithium veins with predicted super-large size resources in the Sizemuzu district of the Keeryin,China 被引量:2
20
作者 Xiang-yuan Yue Xiong Zhou +3 位作者 Yi Zhang Da-xing Gong Yu Zhou Li-ping Luo 《China Geology》 2018年第2期310-311,共2页
1.Objectives Keeryin rare metal ore district is located at the intersection of Markam,Jinchuan and Rangtang counties.More than 1000 pegmatite dykes are associated with the Keeryin granite pluton.These pegmafite dykes ... 1.Objectives Keeryin rare metal ore district is located at the intersection of Markam,Jinchuan and Rangtang counties.More than 1000 pegmatite dykes are associated with the Keeryin granite pluton.These pegmafite dykes are the major source of industrial spodumene ore bodies.Based on the previous studies,we chose Keeryin rare metal ore district as the key target area for geology survey.In this study,we discovered six pegmatite lithium veins in the Sizemuzu district of the Keeryin.Moreover,we study the distribution of regional ore deposits and metallogeny,delineate prospecting target and evaluate the mineralization potential of Lithium. 展开更多
关键词 DISCOVERY PEGMATITE LITHIUM veins Sizemuzu DISTRICT
下载PDF
上一页 1 2 67 下一页 到第
使用帮助 返回顶部