BACKGROUND Idiopathic myointimal hyperplasia of the mesenteric veins(IMHMV)is a rare disease characterized by narrowing of the lumen caused by mesenteric vein intimal hyperplasia,resulting in chronic intestinal ischem...BACKGROUND Idiopathic myointimal hyperplasia of the mesenteric veins(IMHMV)is a rare disease characterized by narrowing of the lumen caused by mesenteric vein intimal hyperplasia,resulting in chronic intestinal ischemia.Although the colorectum is the primary site affected by this condition,involvement of the small intestine is even more rare.Recurrence of IMHMV after surgical resection of the affected bowel is uncommon.CASE SUMMARY In this case report,we present a unique instance of IMHMV exclusively occurring in the small intestine.The patient experienced small intestinal perforation,infarction,and obstruction before receiving a clear diagnosis,which was achieved only during the third operation.In this review,we analyzed 84 reported cases to summarize the etiology,clinical manifestations,and diagnostic challenges of IMHMV,with the aim of raising awareness regarding this rare condition among clinicians.CONCLUSION Notably,IMHMV can also affect the small intestine alone.When refractory enteritis with endoscopic findings of nonspecific ischemic changes is encountered,IMHMV should be considered for potential diagnosis.展开更多
[Objective]Traditional structural geology textbooks often provide outdated treatments of joints and veins,failing to reflect the significant advances made in the past three decades.This review seeks to address part of...[Objective]Traditional structural geology textbooks often provide outdated treatments of joints and veins,failing to reflect the significant advances made in the past three decades.This review seeks to address part of this gap by highlighting the significance of barren joints and veins in reconstructing both the directions and magnitudes of geological paleostresses.[Conclusion]Conjugate shear joints not only indicate the orientation of the three effective principal stresses but also imply differential stresses at least four times greater than the tensile strength of the brittle host rock.Exfoliation joints form under stress states ofσ_(1)≈σ_(2)>0>σ_(3),whereas polygonal columnar joints in sedimentary rocks reflectσ_(1)^(*)>>σ_(2)^(*)=σ_(3)^(*),allowing the tensile strength of rocks to be estimated.Tensile joints in brittle strong beds interlayered with ductile soft layers are primarily driven by tensile stresses transferred from interfacial shear stresses between the hard and soft layers,with joint saturation mainly controlled by tectonic strain.Under natural strain-rate conditions,the Weibull modulus and tensile strength of the strong layers,as well as the shear-flow strength of the ductile layers,can be inferred from the nonlinear relationship between joint spacing and bed thickness.Ladder-like orthogonal joints,which form under a stress state ofσ_(1)^(*)>>σ_(2)^(*)>σ_(3)^(*),divide strata into blocky units and,after weathering and erosion,give rise to characteristic castle-and tower-like landforms.Veins,as mineral-filled joints,provide spacing and thickness data that allow estimates of layer strain.Moreover,the nonlinear relationship between vein spacing and bed thickness permits quantification of the extent to which mineral precipitation restores the tensile strength of rock beds.The absence of ladder-like orthogonal veins is attributed to this strength recovery.[Significance]Collectively,these observations demonstrate the critical role of joints and veins in constraining both the magnitudes and orientations of geological paleostress fields.展开更多
Objective: To evaluate the efficacy of endovenous radiofrequency ablation (RFA) and laser ablation (EVLA) in the treatment of superficial varicose veins of the lower extremities. Methods: Seventy-eight patients with s...Objective: To evaluate the efficacy of endovenous radiofrequency ablation (RFA) and laser ablation (EVLA) in the treatment of superficial varicose veins of the lower extremities. Methods: Seventy-eight patients with superficial varicose veins treated at a hospital between April 2022 and May 2023 were selected and divided into a radiofrequency ablation group (RFA group;39 cases) and a laser ablation group (EVLA group;39 cases) based on the treatment method. Operation time, postoperative recovery duration, venous clinical severity score (VCSS) changes, complication rates, closure rates, and recurrence rates were compared between the groups at 1 month, 3 months, and 12 months postoperatively. The postoperative therapeutic outcomes were comprehensively evaluated. Results: No significant differences in age, gender, disease grade, or disease course were observed between the groups (P > 0.05). The superficial varicose vein closure rate was 100% in both groups at 1 and 3 months postoperatively. At 12 months, the closure rate was 94.87% in the RFA group and 97.43% in the EVLA group, with no statistically significant difference (P > 0.05). No significant differences were observed in VCSS changes or complication incidence between the groups (P > 0.05). Conclusion: Radiofrequency ablation and laser ablation demonstrate comparable efficacy and safety in the treatment of superficial varicose veins of the lower extremities.展开更多
Varicose veins of the lower limbs are a cosmopolitan condition, thought to be rare in Africa but widespread in Europe. The aim of this study is to analyze the indications and evaluate the results of surgical managemen...Varicose veins of the lower limbs are a cosmopolitan condition, thought to be rare in Africa but widespread in Europe. The aim of this study is to analyze the indications and evaluate the results of surgical management of varicose pathology of the IM in Dakar. We enrolled 280 patients, with a mean age of 36 and a sex ratio of 2. Factors favouring venous disease were dominated by prolonged orthostatism and multiparity. The average consultation time was 6 years. The reasons for consultation were functional manifestations, progressive complications and aesthetics. The venous trunks concerned were the great saphenous vein (GSV) in 58.9% of cases, the small saphenous vein (SSV) in 29% of cases, perforating veins and varicose veins were unsystematized in 28.5% of cases. Surgery was performed under spinal anaesthesia. Surgical procedures were dominated by stripping of the GSV, crossectomy of the SSV and staged ligations. One patient developed meningismus immediately after the operation. Average follow-up was 2 years. Mortality was null.展开更多
Objective:To investigate the clinical efficacy and safety of ultrasound-guided local anesthesia for endovenous laser combined with sclerotherapy in the treatment of varicose great saphenous veins.Methods:A total of 53...Objective:To investigate the clinical efficacy and safety of ultrasound-guided local anesthesia for endovenous laser combined with sclerotherapy in the treatment of varicose great saphenous veins.Methods:A total of 53 patients with varicose great saphenous veins admitted to our hospital from December 2023 to June 2025 were selected and divided into a traditional surgery group(18 cases)and a laser combined with sclerotherapy group(35 cases)according to the surgical method.The venous clinical severity score(VCSS),chronic venous insufficiency quality of life questionnaire(CIVIQ)score,visual analog scale(VAS)score for pain,complication rate,surgical time,treatment cost,recovery time,and patient satisfaction were compared between the two groups at 1 week,1 month,and 3 months postoperatively.Results:The VCSS scores of the laser group at each postoperative time point were lower than those of the traditional group,and the CIVIQ scores were higher than those of the traditional group(all p<0.05).The incidence of complications in the laser group(8.57%),the VAS score at 24 hours postoperatively,the duration of pain,and the utilization rate of analgesic medications were all significantly lower than those in the conventional group(all p<0.05).The laser group also demonstrated shorter operative and recovery times compared to the conventional group,along with higher patient satisfaction,albeit at a higher treatment cost(p<0.05).Conclusion:Endovenous laser combined with sclerotherapy under ultrasound guidance for the treatment of great saphenous vein varicosis offers advantages such as minimal trauma,rapid recovery,mild pain,and fewer complications,demonstrating significant clinical efficacy and good safety,thus possessing high clinical application value.展开更多
BACKGROUND Living donor liver transplantation(LDLT)is a crucial alternative to deceased donor transplantation,especially in regions with limited access to cadaveric organs.Right lobe graft implantation into the inferi...BACKGROUND Living donor liver transplantation(LDLT)is a crucial alternative to deceased donor transplantation,especially in regions with limited access to cadaveric organs.Right lobe graft implantation into the inferior vena cava(IVC)requires advanced surgical techniques to optimize outcomes and reduce complications.AIM To compare two venous anastomosis techniques—direct polytetrafluoroethylene(PTFE)grafting of V5-V8 veins to the IVC vs triangulation to the right hepatic vein(RHV)—in terms of graft viability and postoperative outcomes.METHODS A retrospective analysis was conducted on 96 patients who underwent LDLT with right lobe grafts between 2014 and 2023.Patients were divided into three groups:(1)No venous outflow reconstruction;(2)PTFE graft direct anastomosis to the IVC;and(3)PTFE graft anastomosis using triangulation to the RHV.Perioperative and postoperative outcomes,including bile duct complications,alanine aminotransferase/aspartate aminotransferase levels,and graft perfusion,were compared across groups.RESULTS Group 3(triangulation to RHV)showed significantly improved venous outflow,fewer complications,and faster normalization of liver function tests.Bile duct complications were highest in group 1(12.8%)and lowest in group 3(7%).Doppler ultrasonography revealed better graft perfusion in group 3 compared to groups 1 and 2.CONCLUSION Triangulation to the RHV improves graft viability,reduces biliary complications,and enhances early postoperative outcomes compared to direct PTFE grafting to the IVC.展开更多
BACKGROUND Wedged hepatic venous pressure(WHVP)is a crucial variable for accurately assessing the hepatic venous pressure gradient(HVPG)and is vital for the diagnosis and prognostic evaluation of patients with portal ...BACKGROUND Wedged hepatic venous pressure(WHVP)is a crucial variable for accurately assessing the hepatic venous pressure gradient(HVPG)and is vital for the diagnosis and prognostic evaluation of patients with portal hypertension(PH).AIM To investigate the anatomical characteristics of balloon-occluded hepatic venous angiography in patients with PH and analyze the relationship between the WHVP and portal venous pressure(PVP).METHODS This retrospective study included 877 patients with PH who met the inclusion criteria from January 2020 to June 2024.Routine and innovative hepatic venous angiography was performed during transjugular intrahepatic portosystemic shunt procedures to measure hepatic venous and PVPs.All patients'angiographic images were collected for analysis.The associations between WHVP and PVP in each group were analyzed via linear regression analysis,and a predictive model was established.RESULTS The 877 patients had a mean age of 52.6±13.0 years,with 582 males and 295 females.Patients were categorized into four groups on the basis of their anatomical structure.All groups showed strong correlations between WHVP and PVP.The regression coefficient between the WHVP and PVP in the hepatic right vein-portal venous angiography group was 0.884(P<0.05);in the hepatic right vein-accessory hepatic venous angiography group,it was 0.721(P<0.05);in the hepatic right vein-middle hepatic venous angiography group,it was 0.344(P<0.05);and in the hepatic right vein-nonangiography group,it was 0.293(P<0.05).CONCLUSION The presence and anatomical classification of hepatic venous collaterals are key factors influencing the relationship between WHVP with and PVP.Based on the different anatomical classifications of hepatic veins,WHVP can be used to estimate PVP,improving the accuracy of PVP prediction.展开更多
In a bid to identify features useful in discriminating barren from gold-bearing veins and thus assist in the training of locals on site suitability selection for shallow-depth gold exploitation from weathered veins,we...In a bid to identify features useful in discriminating barren from gold-bearing veins and thus assist in the training of locals on site suitability selection for shallow-depth gold exploitation from weathered veins,we investigated a major vein set in the Batouri gold district of eastern Cameroon hereafter referred to as the Mama vein system.The mineralized veins trend NE-SW and are foliated with sericitic,carbonate,sulphides and hematitic alterations.展开更多
[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
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
Serpentinization and calcite precipitation of mantle peridotites exhumed along detachment faults at the slow-to ultraslow-spreading centers can provide important clues to the hydrothermal alteration processes.The Tian...Serpentinization and calcite precipitation of mantle peridotites exhumed along detachment faults at the slow-to ultraslow-spreading centers can provide important clues to the hydrothermal alteration processes.The Tianxiu hydrothermal field is a new-found active and ultramafichosted hydrothermal vent site along the Carlsberg Ridge,Northwest Indian Ocean.Two types of calcite veins are recognized in serpentinized harzburgite samples collected from the seafloor at the water depth of 3 500 m(3.67°N/63.83°E) and 400 m north of Tianxiu hydrothermal field.Calcite veins Ⅰ occur in the fractures that cut through mesh texture in the highly serpentinized harzburgite,while calcite veins Ⅱ precipitate within the mesh texture in the relatively weaker serpentinized harzburgite.Both veins show similar δ13CPDB(+0.54‰ and +0.58‰) but different δ18OPDB(-16.67‰ and +4.46‰) values,suggesting that they were derived from the same carbon source but precipitated at different temperatures.Taking the deep seawater temperature of 2℃as the precipitation temperature of the calcite veins I,the equilibrium δ18OV-SMOW of calcite-precipitating fluid was calculated to be 1.78‰,which is close to the average δ18OV-SMOW value(1.74‰) of vent fluid samples from the ultramafic-hosted hydrothermal systems worldwide.The formation temperature of calcite veins Ⅱ is inferred to be approximately 134℃,based on the calculated δ18OV-SMOW above.The temperature differences of calcite precipitation probably resulted from the fluid cooling conductively and mixing with seawater along the presumed fractures during slow upflow.The low-temperature calcite postdates the mesh texture,while the high-temperature calcite may precipitate under relatively low water/rock ratios,alkaline and reduced conditions among the mesh texture,which is revealed by the geochemical models.Therefore,it is suggested that they both have been influenced by hydrothermal fluids and the sampling site is near the discharge zone of hydrothermal circulation.展开更多
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
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
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
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
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
Calcite veins in carbonate fracture have been investigated by petrographic, fluid inclusion, geochemical analyses and coupled with basin modeling techniques to provide useful insights into fluid activity and deformati...Calcite veins in carbonate fracture have been investigated by petrographic, fluid inclusion, geochemical analyses and coupled with basin modeling techniques to provide useful insights into fluid activity and deformation conditions of the Cambrian to Triassic Shizhu synclinorium from the western region of Mid-Yangtze, central China. The results of the fluid inclusion microthermometry show a wide range of homogenization temperatures（78.6–215.5 °C） and salinities（0.18–23.11 wt.% NaCl equivalent）, indicating the formation under diverse fluid conditions. All the calcite veins have negative Ce anomalies, which are the typical characteristic of marine carbonate sediments; it is therefore plausible that calcite veins were precipitated from the marine basin fluid. The stable carbon isotopic compositions of calcites（δ^（13）CV-PDB=-2.5‰–4.26‰） and host limestones（δ^（13）CV-PDB=-3.56‰–5.80‰） are very similar with a correlation coefficient of 0.86, however, four calcites from the Lower Permian and Lower Triassic show lower δ^（13）C values relative to the host limestones, and they are depleted in total REE concentrations（∑REE ratio varies from 0.74 to 2.06）, suggesting the derivation of dissolved carbon from marine carbonates hosting the calcite veins and, less commonly, from the degradation of organic matter. Calculated δ^（18）O of the fluids-precipitating calcites（δ^（18）OV-SMOW=-0.41‰–14.42‰）, ^（87）Sr/^（86）Sr ratios varying in the range of coeval seawater and the distinct REE pattern simultaneously suggest calcite-forming fluids in each stratigraphic unit could have formed from the involvement of fluids that originated from coeval seawater and evolved through different degrees of water rock interaction. However, the presence of more radiogenic ^（87）Sr/^（86）Sr ratios than coeval seawater and pronounced positive Eu anomalies in calcites of Lower to Middle Ordovician rocks indicate that terrestrial input from upper strata mudstone and siliciclastic rocks could be involved in the precipitation of the Ordovician calcite. Fluid-inclusion data combined with burial and thermal history modeling indicate there was large-scale flow of evolved basinal fluids through the carbonate formation fractures spanning a time frame from 135 to 50 Ma（Early Cretaceous–Eocene）. Therefore, the geochemical characteristics of calcite veins can provide the basis for deformation events in Late Yanshanian and Early Himalayan orogeny.展开更多
基金Supported by the National Natural Science Foundation of China,No.81970493 and No.82270590.
文摘BACKGROUND Idiopathic myointimal hyperplasia of the mesenteric veins(IMHMV)is a rare disease characterized by narrowing of the lumen caused by mesenteric vein intimal hyperplasia,resulting in chronic intestinal ischemia.Although the colorectum is the primary site affected by this condition,involvement of the small intestine is even more rare.Recurrence of IMHMV after surgical resection of the affected bowel is uncommon.CASE SUMMARY In this case report,we present a unique instance of IMHMV exclusively occurring in the small intestine.The patient experienced small intestinal perforation,infarction,and obstruction before receiving a clear diagnosis,which was achieved only during the third operation.In this review,we analyzed 84 reported cases to summarize the etiology,clinical manifestations,and diagnostic challenges of IMHMV,with the aim of raising awareness regarding this rare condition among clinicians.CONCLUSION Notably,IMHMV can also affect the small intestine alone.When refractory enteritis with endoscopic findings of nonspecific ischemic changes is encountered,IMHMV should be considered for potential diagnosis.
文摘[Objective]Traditional structural geology textbooks often provide outdated treatments of joints and veins,failing to reflect the significant advances made in the past three decades.This review seeks to address part of this gap by highlighting the significance of barren joints and veins in reconstructing both the directions and magnitudes of geological paleostresses.[Conclusion]Conjugate shear joints not only indicate the orientation of the three effective principal stresses but also imply differential stresses at least four times greater than the tensile strength of the brittle host rock.Exfoliation joints form under stress states ofσ_(1)≈σ_(2)>0>σ_(3),whereas polygonal columnar joints in sedimentary rocks reflectσ_(1)^(*)>>σ_(2)^(*)=σ_(3)^(*),allowing the tensile strength of rocks to be estimated.Tensile joints in brittle strong beds interlayered with ductile soft layers are primarily driven by tensile stresses transferred from interfacial shear stresses between the hard and soft layers,with joint saturation mainly controlled by tectonic strain.Under natural strain-rate conditions,the Weibull modulus and tensile strength of the strong layers,as well as the shear-flow strength of the ductile layers,can be inferred from the nonlinear relationship between joint spacing and bed thickness.Ladder-like orthogonal joints,which form under a stress state ofσ_(1)^(*)>>σ_(2)^(*)>σ_(3)^(*),divide strata into blocky units and,after weathering and erosion,give rise to characteristic castle-and tower-like landforms.Veins,as mineral-filled joints,provide spacing and thickness data that allow estimates of layer strain.Moreover,the nonlinear relationship between vein spacing and bed thickness permits quantification of the extent to which mineral precipitation restores the tensile strength of rock beds.The absence of ladder-like orthogonal veins is attributed to this strength recovery.[Significance]Collectively,these observations demonstrate the critical role of joints and veins in constraining both the magnitudes and orientations of geological paleostress fields.
基金supported by the 2024 University Scientific Research Project of Guangzhou Education Bureau(Project No.24312286Certificate No.gd20249983112).
文摘Objective: To evaluate the efficacy of endovenous radiofrequency ablation (RFA) and laser ablation (EVLA) in the treatment of superficial varicose veins of the lower extremities. Methods: Seventy-eight patients with superficial varicose veins treated at a hospital between April 2022 and May 2023 were selected and divided into a radiofrequency ablation group (RFA group;39 cases) and a laser ablation group (EVLA group;39 cases) based on the treatment method. Operation time, postoperative recovery duration, venous clinical severity score (VCSS) changes, complication rates, closure rates, and recurrence rates were compared between the groups at 1 month, 3 months, and 12 months postoperatively. The postoperative therapeutic outcomes were comprehensively evaluated. Results: No significant differences in age, gender, disease grade, or disease course were observed between the groups (P > 0.05). The superficial varicose vein closure rate was 100% in both groups at 1 and 3 months postoperatively. At 12 months, the closure rate was 94.87% in the RFA group and 97.43% in the EVLA group, with no statistically significant difference (P > 0.05). No significant differences were observed in VCSS changes or complication incidence between the groups (P > 0.05). Conclusion: Radiofrequency ablation and laser ablation demonstrate comparable efficacy and safety in the treatment of superficial varicose veins of the lower extremities.
文摘Varicose veins of the lower limbs are a cosmopolitan condition, thought to be rare in Africa but widespread in Europe. The aim of this study is to analyze the indications and evaluate the results of surgical management of varicose pathology of the IM in Dakar. We enrolled 280 patients, with a mean age of 36 and a sex ratio of 2. Factors favouring venous disease were dominated by prolonged orthostatism and multiparity. The average consultation time was 6 years. The reasons for consultation were functional manifestations, progressive complications and aesthetics. The venous trunks concerned were the great saphenous vein (GSV) in 58.9% of cases, the small saphenous vein (SSV) in 29% of cases, perforating veins and varicose veins were unsystematized in 28.5% of cases. Surgery was performed under spinal anaesthesia. Surgical procedures were dominated by stripping of the GSV, crossectomy of the SSV and staged ligations. One patient developed meningismus immediately after the operation. Average follow-up was 2 years. Mortality was null.
文摘Objective:To investigate the clinical efficacy and safety of ultrasound-guided local anesthesia for endovenous laser combined with sclerotherapy in the treatment of varicose great saphenous veins.Methods:A total of 53 patients with varicose great saphenous veins admitted to our hospital from December 2023 to June 2025 were selected and divided into a traditional surgery group(18 cases)and a laser combined with sclerotherapy group(35 cases)according to the surgical method.The venous clinical severity score(VCSS),chronic venous insufficiency quality of life questionnaire(CIVIQ)score,visual analog scale(VAS)score for pain,complication rate,surgical time,treatment cost,recovery time,and patient satisfaction were compared between the two groups at 1 week,1 month,and 3 months postoperatively.Results:The VCSS scores of the laser group at each postoperative time point were lower than those of the traditional group,and the CIVIQ scores were higher than those of the traditional group(all p<0.05).The incidence of complications in the laser group(8.57%),the VAS score at 24 hours postoperatively,the duration of pain,and the utilization rate of analgesic medications were all significantly lower than those in the conventional group(all p<0.05).The laser group also demonstrated shorter operative and recovery times compared to the conventional group,along with higher patient satisfaction,albeit at a higher treatment cost(p<0.05).Conclusion:Endovenous laser combined with sclerotherapy under ultrasound guidance for the treatment of great saphenous vein varicosis offers advantages such as minimal trauma,rapid recovery,mild pain,and fewer complications,demonstrating significant clinical efficacy and good safety,thus possessing high clinical application value.
文摘BACKGROUND Living donor liver transplantation(LDLT)is a crucial alternative to deceased donor transplantation,especially in regions with limited access to cadaveric organs.Right lobe graft implantation into the inferior vena cava(IVC)requires advanced surgical techniques to optimize outcomes and reduce complications.AIM To compare two venous anastomosis techniques—direct polytetrafluoroethylene(PTFE)grafting of V5-V8 veins to the IVC vs triangulation to the right hepatic vein(RHV)—in terms of graft viability and postoperative outcomes.METHODS A retrospective analysis was conducted on 96 patients who underwent LDLT with right lobe grafts between 2014 and 2023.Patients were divided into three groups:(1)No venous outflow reconstruction;(2)PTFE graft direct anastomosis to the IVC;and(3)PTFE graft anastomosis using triangulation to the RHV.Perioperative and postoperative outcomes,including bile duct complications,alanine aminotransferase/aspartate aminotransferase levels,and graft perfusion,were compared across groups.RESULTS Group 3(triangulation to RHV)showed significantly improved venous outflow,fewer complications,and faster normalization of liver function tests.Bile duct complications were highest in group 1(12.8%)and lowest in group 3(7%).Doppler ultrasonography revealed better graft perfusion in group 3 compared to groups 1 and 2.CONCLUSION Triangulation to the RHV improves graft viability,reduces biliary complications,and enhances early postoperative outcomes compared to direct PTFE grafting to the IVC.
基金Supported by Capital Medical University Affiliated Beijing Shijitan Hospital Talent Development Program during the 14th Five-Year Plan,No.2023 LJRCLFQ.
文摘BACKGROUND Wedged hepatic venous pressure(WHVP)is a crucial variable for accurately assessing the hepatic venous pressure gradient(HVPG)and is vital for the diagnosis and prognostic evaluation of patients with portal hypertension(PH).AIM To investigate the anatomical characteristics of balloon-occluded hepatic venous angiography in patients with PH and analyze the relationship between the WHVP and portal venous pressure(PVP).METHODS This retrospective study included 877 patients with PH who met the inclusion criteria from January 2020 to June 2024.Routine and innovative hepatic venous angiography was performed during transjugular intrahepatic portosystemic shunt procedures to measure hepatic venous and PVPs.All patients'angiographic images were collected for analysis.The associations between WHVP and PVP in each group were analyzed via linear regression analysis,and a predictive model was established.RESULTS The 877 patients had a mean age of 52.6±13.0 years,with 582 males and 295 females.Patients were categorized into four groups on the basis of their anatomical structure.All groups showed strong correlations between WHVP and PVP.The regression coefficient between the WHVP and PVP in the hepatic right vein-portal venous angiography group was 0.884(P<0.05);in the hepatic right vein-accessory hepatic venous angiography group,it was 0.721(P<0.05);in the hepatic right vein-middle hepatic venous angiography group,it was 0.344(P<0.05);and in the hepatic right vein-nonangiography group,it was 0.293(P<0.05).CONCLUSION The presence and anatomical classification of hepatic venous collaterals are key factors influencing the relationship between WHVP with and PVP.Based on the different anatomical classifications of hepatic veins,WHVP can be used to estimate PVP,improving the accuracy of PVP prediction.
基金funded by the International Union of Geological Science(IUGS)under its“Resourcing Future Generations”programme Coordinated at the University of Buea by CES。
文摘In a bid to identify features useful in discriminating barren from gold-bearing veins and thus assist in the training of locals on site suitability selection for shallow-depth gold exploitation from weathered veins,we investigated a major vein set in the Batouri gold district of eastern Cameroon hereafter referred to as the Mama vein system.The mineralized veins trend NE-SW and are foliated with sericitic,carbonate,sulphides and hematitic alterations.
基金Supported by the Fund of Anhui Provincial Tobacco Monopoly Bureau(AHKJ2008-03)Anhui Provincial University Key Project of Natural Science(KJ2010A114)Undergraduate Student Science and Technology Innovation Fund of Anhui Agricultural University(2010233)~~
文摘[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.
文摘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.
基金funded by the National Key Research and Development Program of China(No.2018YFC0309903)the Scientific Research Fund of the Second Institute of Oceanography,MNR(No.QNYC1701)+1 种基金the China Ocean Mineral Resources R&D Association Project(No.DY135-S2-1-02&05)the National Science Foundation of China(No.41976076)
文摘Serpentinization and calcite precipitation of mantle peridotites exhumed along detachment faults at the slow-to ultraslow-spreading centers can provide important clues to the hydrothermal alteration processes.The Tianxiu hydrothermal field is a new-found active and ultramafichosted hydrothermal vent site along the Carlsberg Ridge,Northwest Indian Ocean.Two types of calcite veins are recognized in serpentinized harzburgite samples collected from the seafloor at the water depth of 3 500 m(3.67°N/63.83°E) and 400 m north of Tianxiu hydrothermal field.Calcite veins Ⅰ occur in the fractures that cut through mesh texture in the highly serpentinized harzburgite,while calcite veins Ⅱ precipitate within the mesh texture in the relatively weaker serpentinized harzburgite.Both veins show similar δ13CPDB(+0.54‰ and +0.58‰) but different δ18OPDB(-16.67‰ and +4.46‰) values,suggesting that they were derived from the same carbon source but precipitated at different temperatures.Taking the deep seawater temperature of 2℃as the precipitation temperature of the calcite veins I,the equilibrium δ18OV-SMOW of calcite-precipitating fluid was calculated to be 1.78‰,which is close to the average δ18OV-SMOW value(1.74‰) of vent fluid samples from the ultramafic-hosted hydrothermal systems worldwide.The formation temperature of calcite veins Ⅱ is inferred to be approximately 134℃,based on the calculated δ18OV-SMOW above.The temperature differences of calcite precipitation probably resulted from the fluid cooling conductively and mixing with seawater along the presumed fractures during slow upflow.The low-temperature calcite postdates the mesh texture,while the high-temperature calcite may precipitate under relatively low water/rock ratios,alkaline and reduced conditions among the mesh texture,which is revealed by the geochemical models.Therefore,it is suggested that they both have been influenced by hydrothermal fluids and the sampling site is near the discharge zone of hydrothermal circulation.
基金funded by the Fundamental Research Funds for National Universities, China University of Geosciences (Wuhan) and China Geological Survey (Grant Nos. 12120113032800, 21201011000150004, DD20190069)
文摘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.
基金funded by the National Key Technology Program during the 13th Five-Year Plan Period (Grant No. 2016ZX05034001-007)National Natural Science Foundation of China (Grant No. 41772359)
文摘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.
基金supported by a grant from the“Famous doctors,Famous hospital,Famous clinic”project of the SHENZHEN municipal government[SZSM201512013].
文摘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.
基金This research was supported by The National Key Research and Development Program of China(Grant No.2019YFD1000301)the Fundamental Research Funds for Central Nonprofit Scientific Institution(Grant No.IVF-BRF2018006)+1 种基金the Key Laboratory of Biology and Genetic Improvement of Horticultural Crops,Ministry of Agriculture,Chinathe Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences(Grant No.CAAS-ASTIP-IVFCAAS).
文摘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.
文摘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.
基金supported by the National Natural Science Foundation of China(No.41672139)supported by Grant(No.2017ZX05005-001-008)from the National Key Scientific Special Project of Chinaprovided by the Programme of Introducing Talents of Discipline to Universities(No.B14031)
文摘Calcite veins in carbonate fracture have been investigated by petrographic, fluid inclusion, geochemical analyses and coupled with basin modeling techniques to provide useful insights into fluid activity and deformation conditions of the Cambrian to Triassic Shizhu synclinorium from the western region of Mid-Yangtze, central China. The results of the fluid inclusion microthermometry show a wide range of homogenization temperatures（78.6–215.5 °C） and salinities（0.18–23.11 wt.% NaCl equivalent）, indicating the formation under diverse fluid conditions. All the calcite veins have negative Ce anomalies, which are the typical characteristic of marine carbonate sediments; it is therefore plausible that calcite veins were precipitated from the marine basin fluid. The stable carbon isotopic compositions of calcites（δ^（13）CV-PDB=-2.5‰–4.26‰） and host limestones（δ^（13）CV-PDB=-3.56‰–5.80‰） are very similar with a correlation coefficient of 0.86, however, four calcites from the Lower Permian and Lower Triassic show lower δ^（13）C values relative to the host limestones, and they are depleted in total REE concentrations（∑REE ratio varies from 0.74 to 2.06）, suggesting the derivation of dissolved carbon from marine carbonates hosting the calcite veins and, less commonly, from the degradation of organic matter. Calculated δ^（18）O of the fluids-precipitating calcites（δ^（18）OV-SMOW=-0.41‰–14.42‰）, ^（87）Sr/^（86）Sr ratios varying in the range of coeval seawater and the distinct REE pattern simultaneously suggest calcite-forming fluids in each stratigraphic unit could have formed from the involvement of fluids that originated from coeval seawater and evolved through different degrees of water rock interaction. However, the presence of more radiogenic ^（87）Sr/^（86）Sr ratios than coeval seawater and pronounced positive Eu anomalies in calcites of Lower to Middle Ordovician rocks indicate that terrestrial input from upper strata mudstone and siliciclastic rocks could be involved in the precipitation of the Ordovician calcite. Fluid-inclusion data combined with burial and thermal history modeling indicate there was large-scale flow of evolved basinal fluids through the carbonate formation fractures spanning a time frame from 135 to 50 Ma（Early Cretaceous–Eocene）. Therefore, the geochemical characteristics of calcite veins can provide the basis for deformation events in Late Yanshanian and Early Himalayan orogeny.
