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A Case of Esophageal Perforation Presenting as Cavitary Pneumonia: Diagnostic and Therapeutic Challenges
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作者 Feruza Abraamyan Harpreet Singh +1 位作者 Vishal Raj Inder M. Singh 《Open Journal of Gastroenterology》 CAS 2024年第7期241-247,共7页
Esophageal perforation, a rare condition, can arise from iatrogenic, traumatic, or spontaneous origins. Even when therapy is initiated within the first 24 hours, it is associated with a mortality rate of up to 25%. Du... Esophageal perforation, a rare condition, can arise from iatrogenic, traumatic, or spontaneous origins. Even when therapy is initiated within the first 24 hours, it is associated with a mortality rate of up to 25%. Due to the varied initial presentation, treatment may be delayed, leading to poorer outcomes. Here, we present a unique case of a 27-year-old schizophrenic patient who initially presented with acute respiratory failure and septic shock and was ultimately diagnosed with cavitary pneumonia secondary to esophageal perforation. 展开更多
关键词 Esophageal perforation Foreign Body Esophageal Stent Cavitary Pneumonia Septic Shock Respiratory Failure
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Evolution and Application of Sealing Ability of Gypsum Caprocks under Temperature-Pressure Coupling:An Example of the ZS5 Well in the Tazhong Area of the Tarim Basin
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作者 LIU Hua ZHAO Shan +3 位作者 YANG Xianzhang ZHU Yongfeng WANG Shen ZHANG Ke 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第1期168-184,共17页
Gypsum caprocks'sealing ability is affected by temperature-pressure coupling.Due to the limitations of experimental conditions,there is still a lack of triaxial stress-strain experiments that simultaneously consid... Gypsum caprocks'sealing ability is affected by temperature-pressure coupling.Due to the limitations of experimental conditions,there is still a lack of triaxial stress-strain experiments that simultaneously consider changes in temperature and pressure conditions,which limits the accuracy of the comprehensive evaluation of the brittle plastic evolution and sealing ability of gypsum rocks using temperature pressure coupling.Triaxial stress-strain tests were utilized to investigate the differences in the evolution of the confinement capacity of gypsum rocks under coupled temperaturepressure action and isothermal-variable pressure action on the basis of sample feasibility analysis.According to research,the gypsum rock's peak and residual strengths decrease under simultaneous increases in temperature and pressure over isothermal pressurization experimental conditions,and it becomes more ductile.This reduces the amount of time it takes for the rock to transition from brittle to plastic.When temperature is taken into account,both the brittle–plastic transformation's depth limit and the lithological transformation of gypsum rocks become shallower,and the evolution of gypsum rocks under variable temperature and pressure conditions is more complicated than that under isothermal pressurization.The sealing ability under the temperature-pressure coupling is more in line with the actual geological context when the application results of the Well#ZS5 are compared.This provides a theoretical basis for precisely determining the process of hydrocarbon accumulation and explains why the early hydrocarbon were not well preserved. 展开更多
关键词 temperature-pressure coupling gypsum caprocks brittle-plastic evolution sealing capacity Tarim Basin
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The Evolutionary Profile of Patients Operated for Peptic Ulcer Perforation in Bujumbura
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作者 Jean Claude Mbonicura Prudence Bukuru +4 位作者 Stanislas Harakandi Frank Ijeneza Révérien Ndayirorere François Nduwimana Astère Mbonicura 《Surgical Science》 2024年第1期7-18,共12页
Background: The evolutionary profile of patients operated for peptic ulcer perforation in Bujumbura. Perforated peptic ulcer is a serious complication of peptic ulcer with potential risk of grave complications. Aim: T... Background: The evolutionary profile of patients operated for peptic ulcer perforation in Bujumbura. Perforated peptic ulcer is a serious complication of peptic ulcer with potential risk of grave complications. Aim: To study the early morbidity and mortality of surgery for peptic ulcer perforation in Bujumbura City Hall hospitals: Kamenge University Hospital Center (CHUK), Kamenge Military Hospital (HMK) and Prince Louis Rwagasore Clinic (CPLR). Patients and methods: This is a retrospective, descriptive and analytical study carried out in the three hospitals of Bujumbura over a period of three years from January 1, 2020 to December 31, 2022. It involved 57 cases (n = 57) of peptic ulcer perforation. Results: The frequency of surgery for peptic ulcer perforation was 2.7% with a mean age of 43.6 years +/- 15.3 years and a male predominance with a sex ratio of 3.7. Eight percent of patients presented with shock, 24.5% were smokers, and 67.9% had taken non steroidal anti-inflammatory drugs. The mean hospital stay was 15.2 days with a standard deviation of 12.1. The morbidity rate was 30.2%, 32% were classified in grade IIIb of the Clavien-Dindo Surgical Complications Scale. There were 9 deaths (17%). Seven patients who underwent surgery and received late consultations died. Conclusion: Surgery for peptic ulcer perforation remains an intervention associated with a high rate of morbidity and mortality in Bujumbura. Surgery for peptic ulcer perforation remains a procedure associated with a high morbidity and mortality rate in Bujumbura. The time before consultation was the only factor associated with early morbidity and mortality of Surgery for peptic ulcer’s perforations. 展开更多
关键词 PERITonITIS Peptic Ulcer perforation COMPLICATIonS
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Fracture sealing performance of granular lost circulation materials at elevated temperature:A theoretical and coupled CFD-DEM simulation study
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作者 Chong Lin Qi-Cong Xu +4 位作者 Lie-Xiang Han Gao Li Hai He Hong-Ling Zhou Ji-Ping She 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期567-581,共15页
Lost circulation is a common downhole problem of drilling in geothermal and high-temperature,high-pressure(HTHP)formations.Lost circulation material(LCM)is a regular preventive and remedial measure for lost circulatio... Lost circulation is a common downhole problem of drilling in geothermal and high-temperature,high-pressure(HTHP)formations.Lost circulation material(LCM)is a regular preventive and remedial measure for lost circulation.However,conventional LCMs seem ineffective in high-temperature formations.This may be due to the changes in the mechanical properties of LCMs and their sealing performance under high-temperature conditions.To understand how high temperature affects the fracture sealing performance of LCMs,we developed a coupled computational fluid dynamics-discrete element method(CFD-DEM)model to simulate the behavior of granular LCMs in fractures.We summarized the literature on the effects of high temperature on the mechanical properties of LCMs and the rheological properties of drilling fluid.We conducted sensitivity analyses to investigate how changing LCM slurry properties affected the fracture sealing efficiency at increasing temperatures.The results show that high temperature reduces the size,strength,and friction coefficient of LCMs as well as the drilling fluid viscosity.Smaller,softer,and less frictional LCM particles have lower bridging probability and slower bridging initiation.Smaller particles tend to form dual-particle bridges rather than single-particle bridges.These result in a deeper,tighter,but unstable sealing zone.Reduced drilling fluid viscosity leads to faster and shallower sealing zones. 展开更多
关键词 Geothermal well drilling HTHP formationLost circulation material CFD-DEM Fracture sealing
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Dynamic evaluation on sealing capacity of caprocks of the Meso-Neoproterozoic reservoirs in Ordos Basin,China
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作者 Yusong Yuan Yunqin Hao Rongqiang Zhang 《Energy Geoscience》 EI 2024年第1期99-107,共9页
The Meso-Neoproterozoic is a new play in the Ordos Basin.A deeper understanding about the dynamic relationship between the caprocks and the source rocks is needed.Based on the comprehensive analysis of hydrocarbon sou... The Meso-Neoproterozoic is a new play in the Ordos Basin.A deeper understanding about the dynamic relationship between the caprocks and the source rocks is needed.Based on the comprehensive analysis of hydrocarbon source development characteristics of the Meso-Neoproterozoic and its overlying strata,as well as the formation contact relationships,lithology characteristics and exploratory drilling data,it is recognized that the Meso-Neoproterozoic contains two types of petroleum accumulation assemblage,that is,the“self-sourced indigenous”and“upper source rock-lower reservoir”assemblages.The former is mainly controlled by the development and distribution of source rocks of the Changcheng System,with the Lower Cambrian shale sequence as its caprock.The later is controlled by the superposition between the Meso-Neoproterozoic and its overlying source rocks and this assemblage is mainly distributed in Hangjinqi and Pingliang areas with the Carboniferous-Permian shale sequence as its caprock.The dynamic evaluation on the displacement pressure serves to reconstruct the displacement pressure history of the caprock.The results show that the shale sequence of the Cambrian Maozhuang Formation in well XY 1 in the southern Ordos Basin has possibly acquired the ability of sealing natural gas since the early of Late Triassic.Its displacement pressure increased rapidly up to 20 MPa during the Late Triassic-Jurassic and keeps at 9.2 MPa at present,indicating fair sealing ability.The Carboniferous-Permian caprocks in Hangjinqi area could have acquired the ability to seal natural gas in the Late Jurassic-Early Cretaceous,and the present-day displacement pressure is 9e12 MPa,indicating good sealing ability.The upper Paleozoic caprock in Pingliang area has been able to seal natural gas since the Early Jurassic,with a maximum displacement pressure of 23 MPa during the Cretaceous period and a current value of 17 e20 MPa,indicative of strong ability to seal natural gas.The sealing ability of caprocks of both the“selfsourced indigenous”and“upper source rock-lower reservoir”assemblages has come into being earlier than or at least no later than the peak gas generation of the source rocks and therefore the caprocks are dynamically effective in geohistory.The Meso-Neoproterozoic reservoirs in the Ordos Basin are well preserved and probabally of better potential for exploration in terms of the caprock-source rock combination. 展开更多
关键词 Ordos Basin MESO-NEOPROTEROZOIC Caprock sealing ability Displacement pressure
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Clinical Epidemiology and Surgical Treatment of Spontaneous Perforations of the Terminal Ileum: A Multicentre Study in Cameroon
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作者 Eric Patrick Savom Richard II Mbele +5 位作者 Mahamat Yannick Ekani Boukar Abdal Deudeu Cédric Paterson Atangana Fred Dikongue Dikongue Guy Aristide Bang Marc Leroy Guifo 《Surgical Science》 2024年第5期311-320,共10页
Background: Perforations of the terminal ileum are a frequent clinical situation and a therapeutic challenge. Surgical treatment is controversial. Several surgical modalities have been proposed and postoperative morbi... Background: Perforations of the terminal ileum are a frequent clinical situation and a therapeutic challenge. Surgical treatment is controversial. Several surgical modalities have been proposed and postoperative morbidity and mortality remain high. The aim of this study was to review our experience in the surgical management of perforations of the terminal ileum. Patients and methods: This is a descriptive cross-sectional study with retrospective data collection from January 1, 2017 to December 31, 2021, in five hospitals in Cameroon. Patients’ demographic, clinical presentation, surgical findings and 30-days postoperative outcomes data were collected. Results: We collected 34 files. The sex ratio was 1.4 and the average age was 20.28 years. The average consultation time was 9.1 days. Abdominal pain was present in all our patients. Peritoneal irritation was present in 46 cases (88.5%). The mean time to treatment after admission was 17.5 hours. The perforation was unique in 40 cases (76.9%) and located between 6 and 10 cm from the ileocecal valve in 29 cases (55.8%). Typhoid was the most suspected etiology intraoperatively in 38 cases (73.1%). A simple suture was performed in 18 patients (34.6%), resection with anastomosis in 11 patients (21.2%) and an ileostomy in 5 patients (9.6%). The average length of hospitalization was 21.74 days. Postoperative morbidity and mortality were 32.7% and 17.3% respectively. Conclusion: Perforations of the terminal ileum are common and affect young people. Surgical procedures are varied. Reducing consultation and care times and respecting treatment principles could improve postoperative morbidity and mortality, which remain high. 展开更多
关键词 perforation of the Terminal Ileum Simple Suture RESECTIon MORBIDITY MORTALITY
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Efficacy of Cyanoacrylate Tissue Adhesive Application in the Management of Corneal Perforations at Preah Ang Duong Hospital in Cambodia
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作者 Guechlaing Chea Amarin Mar +3 位作者 Saly Saint Remy Tor Ponndara Ith Piseth Kong 《Open Journal of Ophthalmology》 2024年第1期44-54,共11页
Purpose: The study was to evaluate the efficacy of cyanoacrylate tissue adhesive (CTA) application in corneal perforations. Method: This was a prospective study on 20 patients of corneal perforations who received cyan... Purpose: The study was to evaluate the efficacy of cyanoacrylate tissue adhesive (CTA) application in corneal perforations. Method: This was a prospective study on 20 patients of corneal perforations who received cyanoacrylate tissue adhesive application as treatment between March 2021 and March 2022 at Preah Ang Duong Hospital. The primary outcome measure was success rate of CTA application, while the secondary outcome was to measure postoperative best-corrected visual acuity (BCVA) and ocular complications. Results: The mean age of patients was 44.15 ± 16.05 years old and 7 (35%) were female. Causes of perforation were microbial infection in 12 patients (60%), trauma in 5 patients (25%), and sterile melting in 3 patients (15%). The perforation of size smaller than 1.5 mm was in 8 patients (40%) while 12 patients (60%) had perforated size between 1.5 mm to 3 mm. The perforation was 60% (12 patients) central, 25% (5 patients) paracentral, and 15% (3 patients) peripherally. Out of 20 patients, 5 patients (25%) received CTA application more than 1 time. The mean glue retention was 57.60 ± 31.84 days. Success rate of glue application (defined as intact globe without surgical intervention regardless of number of CTA applications) was 85%. At the last visit, 7 patients (35%) had BCVA of 6/120 or better. Common complications were uveitis (45%), ocular hypertension (30%), cataract (25%) and neovascularization (20%). No serious complications were found. Conclusion: Cyanoacrylate tissue adhesive is an effective treatment option in sealing corneal perforations with no serious complications. . 展开更多
关键词 Cyanoacrylate Tissue Adhesive Corneal perforation Microbial Infection Sterile Melting
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Evaluation of the dynamic sealing performance of cap rocks of underground gas storage under multi-cycle alternating loads
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作者 Lidong Mi Yandong Guo +3 位作者 Yanfeng Li Daqian Zeng Chunhua Lu Guangquan Zhang 《Energy Geoscience》 EI 2024年第4期125-132,共8页
The static sealing of underground gas storage(UGS),including the integrity of cap rocks and the stability of faults,is analyzed from a macro perspective using a comprehensive geological evaluation method.Changes in po... The static sealing of underground gas storage(UGS),including the integrity of cap rocks and the stability of faults,is analyzed from a macro perspective using a comprehensive geological evaluation method.Changes in pore structure,permeability,and mechanical strength of cap rocks under cyclic loads may impact the rock sealing integrity during the injection and recovery phases of UGS.In this work,the mechanical deformation and failure tests of rocks,as well as rock damage tests under alternating loads,are conducted to analyze the changes in the strength and permeability of rocks under multiple-cycle intense injection and recovery of UGS.Additionally,this study proposes an evaluation method for the dynamic sealing performance of UGS cap rocks under multi-cycle alternating loads.The findings suggest that the failure strength(70%)can be used as the critical value for rock failure,thus providing theoretical support for determining the upper limit of operating pressure and the number of injection-recovery cycles for the safe operation of a UGS system. 展开更多
关键词 Alternating load Cap rock Dynamic sealing performance Underground gas storage
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How to preserve the native or reconstructed esophagus after perforations or postoperative leaks: A multidisciplinary 15-year experience
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作者 Dania Nachira Giuseppe Calabrese +21 位作者 Alessia Senatore Valerio Pontecorvi Khrystyna Kuzmych Claudia Belletatti Ivo Boskoski Elisa Meacci Alberto Biondi Federico Raveglia Vincenzo Bove Maria Teresa Congedo Maria Letizia Vita Gloria Santoro Leonardo Petracca Ciavarella Filippo Lococo Giovanni Punzo Angelo Trivisonno Francesco Petrella Federico Barbaro Cristiano Spada Domenico D'Ugo Ugo Cioffi Stefano Margaritora 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第11期3471-3483,共13页
BACKGROUND Esophageal perforation or postoperative leak after esophageal surgery remain a life-threatening condition.The optimal management strategy is still unclear.AIM To determine clinical outcomes and complication... BACKGROUND Esophageal perforation or postoperative leak after esophageal surgery remain a life-threatening condition.The optimal management strategy is still unclear.AIM To determine clinical outcomes and complications of our 15-year experience in the multidisciplinary management of esophageal perforations and anastomotic leaks.METHODS A retrospective single-center observational study was performed on 60 patients admitted at our department for esophageal perforations or treated for an anastomotic leak developed after esophageal surgery from January 2008 to December 2023.Clinical outcomes were analyzed,and complications were evaluated to investigate the efficacy and safety of our multidisciplinary management based on the preservation of the native or reconstructed esophagus,when feasible.RESULTS Among the whole series of 60 patients,an urgent surgery was required in 8 cases due to a septic state.Fifty-six patients were managed by endoscopic or hybrid treatments,obtaining the resolution of the esophageal leak/perforation without removal of the native or reconstructed esophagus.The mean time to resolution was 54.95±52.64 days,with a median of 35.5 days.No severe complications were recorded.Ten patients out of 56(17.9%)developed pneumonia that was treated by specific antibiotic therapy,and in 6 cases(10.7%)an atrial fibrillation was recorded.Seven patients(12.5%)developed a stricture within 12 months,requiring one or two endoscopic pneumatic dilations to solve the problem.Mortality was 1.7%.CONCLUSION A proper multidisciplinary approach with the choice of the most appropriate treatment can be the key for success in managing esophageal leaks or perforations and preserving the esophagus. 展开更多
关键词 Esophageal perforations Postoperative leak Endoscopic vacuum-assisted closure therapy Metal stent Endoscopic suture Lateral esophagostomy Autologous emulsified stromal vascular fraction
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Application of Choquet Integral-Importance-Performance Analysis and TOPSIS Methods in Approaching the Preference Factors of Calligraphy and Seal Engraving Imagery
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作者 Yu Hsuan Chang Jiann Sheng Jiang Min Min Lin 《Journal of Contemporary Educational Research》 2024年第5期276-288,共13页
Classical Chinese characters,presented through calligraphy,seal engraving,or painting,can exhibit different aesthetics and essences of Chinese characters,making them the most important asset of the Chinese people.Call... Classical Chinese characters,presented through calligraphy,seal engraving,or painting,can exhibit different aesthetics and essences of Chinese characters,making them the most important asset of the Chinese people.Calligraphy and seal engraving,as two closely related systems in traditional Chinese art,have developed through the ages.Due to changes in lifestyle and advancements in modern technology,their original functions of daily writing and verification have gradually diminished.Instead,they have increasingly played a significant role in commercial art.This study utilizes the Evaluation Grid Method(EGM)and the Analytic Hierarchy Process(AHP)to research the key preference factors in the application of calligraphy and seal engraving imagery.Different from the traditional 5-point equal interval semantic questionnaire,this study employs a non-equal interval semantic questionnaire with a golden ratio scale,distinguishing the importance ratio of adjacent semantic meanings and highlighting the weighted emphasis on visual aesthetics.Additionally,the study uses Importance-Performance Analysis(IPA)and Technique for Order Preference by Similarity to Ideal Solution(TOPSIS)to obtain the key preference sequence of calligraphy and seal engraving culture.Plus,the Choquet integral comprehensive evaluation is used as a reference for IPA comparison.It is hoped that this study can provide cultural imagery references and research methods,injecting further creativity into industrial design. 展开更多
关键词 Evaluation Grid Method Analytic Hierarchy Process CALLIGRAPHY seal engraving Importance-Performance Analysis Choquet integral TOPSIS
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Sealing capacity evaluation of underground gas storage under intricate geological conditions 被引量:1
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作者 Guangquan Zhang Sinan Zhu +4 位作者 Daqian Zeng Yuewei Jia Lidong Mi Xiaosong Yang Junfa Zhang 《Energy Geoscience》 EI 2024年第3期234-243,共10页
Evaluating underground gas storage(UGS)sealing capacity is essential for its safe construction and operational efficiency.This involves evaluating both the static sealing capacity of traps during hydrocarbon accumulat... Evaluating underground gas storage(UGS)sealing capacity is essential for its safe construction and operational efficiency.This involves evaluating both the static sealing capacity of traps during hydrocarbon accumulation and the dynamic sealing capacity of UGS under intensive gas injection and withdrawal,and alternating loads.This study detailed the methodology developed by Sinopec.The approach merges disciplines like geology,geomechanics,and hydrodynamics,employing both dynamic-static and qualitative-quantitative analyses.Sinopec's evaluation methods,grounded in the in situ stress analysis,include mechanistic studies,laboratory tests,geological surveys,stress analysis,and fluid-solid interactions.Through tests on the static and dynamic sealing capacity of UGS,alongside investigations into sealing mechanisms and the geological and geomechanical properties of cap rocks and faults,A geomechanics-rock damage-seepage mechanics dynamic coupling analysis method has been developed to predict in situ stress variations relative to pore pressure changes during UGS operations and evaluate fault sealing capacity and cap rock integrity,thereby setting the maximum operational pressures.Utilizing this evaluation technique,Sinopec has defined performance metrics and criteria for evaluating the sealing capacity of depleted gas reservoirs,enabling preliminary sealing capacity evaluations at UGS sites.These evaluations have significantly informed the design of UGS construction schemes and the evaluation of fault sealing capacity and cap rock integrity during UGS operations. 展开更多
关键词 Underground gas storage sealing capacity GEOMECHANICS Maximum operational pressure
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The Application of Bilayer Artificial Dermis Combined with VSD Technology in Chronic Wounds 被引量:1
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作者 Xianjin Dong Huasong Luo 《Journal of Biosciences and Medicines》 2024年第3期238-244,共7页
Background: Bilayer artificial dermis promotes wound healing and offers a treatment option for chronic wounds. Aim: Examine the clinical efficacy of bilayer artificial dermis combined with Vacuum Sealing Drainage (VSD... Background: Bilayer artificial dermis promotes wound healing and offers a treatment option for chronic wounds. Aim: Examine the clinical efficacy of bilayer artificial dermis combined with Vacuum Sealing Drainage (VSD) technology in the treatment of chronic wounds. Method: From June 2021 to December 2023, our hospital treated 24 patients with chronic skin tissue wounds on their limbs using a novel tissue engineering product, the bilayer artificial dermis, in combination with VSD technology to repair the wounds. The bilayer artificial dermis protects subcutaneous tissue, blood vessels, nerves, muscles, and tendons, and also promotes the growth of granulation tissue and blood vessels to aid in wound healing when used in conjunction with VSD technology for wound dressing changes in chronic wounds. Results: In this study, 24 cases of chronic wounds with exposed bone or tendon larger than 1.0 cm2 were treated with a bilayer artificial skin combined with VSD dressing after wound debridement. The wounds were not suitable for immediate skin grafting. At 2 - 3 weeks post-treatment, good granulation tissue growth was observed. Subsequent procedures included thick skin grafting or wound dressing changes until complete wound healing. Patients were followed up on average for 3 months (range: 1 - 12 months) post-surgery. Comparative analysis of the appearance, function, skin color, elasticity, and sensation of the healed chronic wounds revealed superior outcomes compared to traditional skin fl repairs, resulting in significantly higher satisfaction levels among patients and their families. Conclusion: The application of bilayer artificial dermis combined with VSD technology for the repair of chronic wounds proves to be a viable method, yielding satisfactory therapeutic effects compared to traditional skin flap procedures. 展开更多
关键词 Bilayer Artificial Dermis Vacuum sealing Drainage (VSD) Chronic Wounds Wound Healing APPLICATIon
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Interfacial friction effects on sealing performances of elastomer packer
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作者 Peng-Cheng Wang Ming-Hui Chen +2 位作者 Jim Jenkinson Yong-Xin Song Li Sun 《Petroleum Science》 SCIE EI CAS CSCD 2024年第3期2037-2047,共11页
Elastomer sealing performance is of critical importance for downhole tools application including the use of fracturing(Frac)plugs during multi-stage hydraulic fracking.In practice sealing performances of such plugs ar... Elastomer sealing performance is of critical importance for downhole tools application including the use of fracturing(Frac)plugs during multi-stage hydraulic fracking.In practice sealing performances of such plugs are normally evaluated through pressure tests,and in numerical simulation studies,maximum contact stress,average contact stress and contact length data are used to determine sealing quality between a packer and casing.In previous studies,the impact of friction forces on sealing performance is often overlooked.This work aims to fill this knowledge gap in determining the influence of friction forces on elastomer packer sealing performances.We first determined the most appropriate constitutive hyperelastic model for the elastomers used in frac plug.Then we compared analytical calculation results with Finite Element Analysis simulation using a simplified tubular geometry and showed the significant influences on interfacial friction on elastomer packer stress distribution,deformation,and contact stress after setting.With the demonstration of validity of FEA method,we conducted systematic numerical simulation studies to show how the interfacial friction coefficients can affect the maximum contact stress,average contact stress,contact stress distribution,and maximum mises stress for an actual packer used in plug products.In addition,we also demonstrated how the groove in a packer can affect packer deformation and evolvement during setting with the consideration of interfacial stress.This study underscores the critical role that friction forces play in Frac plug performance and provides a new dimension for optimizing packer design by controlling interfacial interactions at the packer contact surfaces. 展开更多
关键词 Elastomer seal FRICTIon sealing performance Contact stress
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Numerical Analysis of Perforation during Hydraulic Fracture Initiation Based on Continuous-Discontinuous Element Method
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作者 Rui Zhang Lixiang Wang +2 位作者 Jing Li Chun Feng Yiming Zhang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第8期2103-2129,共27页
Perforation is a pivotal technique employed to establish main flow channels within the reservoir formation at the outset of hydraulic fracturing operations.Optimizing perforation designs is critical for augmenting the... Perforation is a pivotal technique employed to establish main flow channels within the reservoir formation at the outset of hydraulic fracturing operations.Optimizing perforation designs is critical for augmenting the efficacy of hydraulic fracturing and boosting oil or gas production.In this study,we employ a hybrid finite-discrete element method,known as the continuous–discontinuous element method(CDEM),to simulate the initiation of post-perforation hydraulic fractures and to derive enhanced design parameters.The model incorporates the four most prevalent perforation geometries,as delineated in an engineering technical report.Real-world perforations deviate from the ideal cylindrical shape,exhibiting variable cross-sectional profiles that typically manifest as an initial constriction followed by an expansion,a feature consistent across all four perforation types.Our simulations take into account variations in perforation hole geometries,cross-sectional diameters,and perforation lengths.The findings show that perforations generated by the 39g DP3 HMX perforating bullet yield the lowest breakdown pressure,which inversely correlates with increases in sectional diameter and perforation length.Moreover,this study reveals the relationship between breakdown pressure and fracture degree,providing valuable insights for engineers and designers to refine perforation strategies. 展开更多
关键词 Hydraulic fracturing real perforation shape breakdown pressure perforation layout design CDEM
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The influences of perforating phase and bedding planes on the fracture deflection in laminated shale
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作者 Ming-Zhe Gu Mao Sheng +2 位作者 Xiao-Ying Zhuang Xin-Yi Li Gen-Sheng Li 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期1221-1230,共10页
The perforating phase leads to complex and diverse hydraulic fracture propagation behaviors in laminated shale formations. In this paper, a 2D high-speed imaging scheme which can capture the interaction between perfor... The perforating phase leads to complex and diverse hydraulic fracture propagation behaviors in laminated shale formations. In this paper, a 2D high-speed imaging scheme which can capture the interaction between perforating phase and natural shale bedding planes was proposed. The phase field method was used to simulate the same conditions as in the experiment for verification and hydraulic fracture propagation mechanism under the competition of perforating phase and bedding planes was discussed.The results indicate that the bedding planes appear to be no influence on fracture propagation while the perforating phase is perpendicular to the bedding planes, and the fracture propagates along the perforating phase without deflection. When the perforating phase algins with the bedding planes, the fracture initiation pressure reserves the lowest value, and no deflection occurs during fracture propagation. When the perforating phase is the angle 45°, 60°and 75°of bedding planes, the bedding planes begin to play a key role on the fracture deflection. The maximum deflection degree is reached at the perforating phase of75°. Numerical simulation provides evidence that the existence of shale bedding planes is not exactly equivalent to anisotropy for fracture propagation and the difference of mechanical properties between different shale layers is the fundamental reason for fracture deflection. The findings help to understand the intrinsic characteristics of shale and provide a theoretical basis for the optimization design of field perforation parameters. 展开更多
关键词 SHALE Propagation PERFORATING BEDDING Structure
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Conquer coronary artery perforation with magic hands
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作者 Yi-Lun ZOU Jian-Qiang LI +3 位作者 Ding-Yu WANG Yong-Tai GONG Li SHENG Yue LI 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2024年第4期379-386,共8页
Coronary artery perforation(CAP) poses a significant challenge for interventional cardiologists. Management of CAP depends on the location and severity of the perforation. The conventional method for addressing the pe... Coronary artery perforation(CAP) poses a significant challenge for interventional cardiologists. Management of CAP depends on the location and severity of the perforation. The conventional method for addressing the perforation of large vessels involves the placement of a covered stent, while the perforation of distal and collateral vessels is typically managed using coils, autologous skin, subcutaneous fat, microspheres, gelatin sponge, thrombin or other substances. However, the above techniques have certain limitations and are not applicable in all scenarios. Our team has developed a range of innovative strategies for effectively managing CAP. This article provides an insightful review of the various tips and tricks for the treatment of CAP. 展开更多
关键词 CORonARY SPonGE perforation
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Research on the Encapsulation Device for Lunar Samples
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作者 Yonggang Du Chunyong Wang +3 位作者 Haoling Li Ying Zhou Ming Ji Xuesong Wang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第3期104-117,共14页
The encapsulation of lunar samples is a core research area in the third phase of the Chinese Lunar Exploration Program.The seal assembly,opening and closing mechanism(OCM),and locking mechanism are the core components... The encapsulation of lunar samples is a core research area in the third phase of the Chinese Lunar Exploration Program.The seal assembly,opening and closing mechanism(OCM),and locking mechanism are the core components of the encapsulation device of the lunar samples,and the requirements of a tight seal,lightweight,and low power make the design of these core components difficult.In this study,a combined sealing assembly,OCM,and locking mechanism were investigated for the device.The sealing architecture consists of rubber and an Ag-In alloy,and a theory was built to analyze the seal.Experiments of the electroplate Au coating on the knife-edge revealed that the hermetic seal can be significantly improved.The driving principle for coaxial double-helical pairs was investigated and used to design the OCM.Moreover,a locking mechanism was created using an electric initiating explosive device with orifice damping.By optimizing the design,the output parameters were adjusted to meet the requirements of the lunar explorer.The experimental results showed that the helium leak rate of the test pieces were not more than 5×10^(-11) Pa·m^(3)·s^(-1),the minimum power of the OCM was 0.3 W,and the total weight of the principle prototype was 2.9 kg.The explosive driven locking mechanism has low impact.This investigation solved the difficulties in achieving tight seal,light weight,and low power for the lunar explorer,and the results can also be used to explore other extraterrestrial objects in the future. 展开更多
关键词 Lunar samples ENCAPSULATIon Vacuum seal MECHANISM
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Study on the effect of thermal deformation on the liquid seal of high-temperature molten salt pump in molten salt reactor 被引量:2
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作者 Xing‑Chao Shen Yuan Fu Jian‑Yu Zhang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第2期128-138,共11页
The high-temperature molten salt pump is the core equipment in a molten salt reactor that drives the flow of the molten salt coolant.Rotor stability is key to the continuous and reliable operation of the molten salt p... The high-temperature molten salt pump is the core equipment in a molten salt reactor that drives the flow of the molten salt coolant.Rotor stability is key to the continuous and reliable operation of the molten salt pump,and the liquid seal at the wear ring can affect the dynamic characteristics of the rotor system.When the molten salt pump is operated in the hightemperature molten salt medium,thermal deformation of the submerged parts inevitably occurs,changing clearance between the stator and rotor,affecting the leakage and dynamic characteristics of the seal.In this study,the seal leakage,seal dynamic characteristics,and rotor system dynamic characteristics are simulated and analyzed using finite element simulation software based on two cases of considering the effect of seal thermal deformation effect or not.The results show a significant difference in the leakage characteristics and dynamic characteristics of the seal obtained by considering the effect of seal thermal deformation and neglecting the effect of thermal deformation.The leakage flow rate decreases,and the first-order critical speed of the seal-bearing-rotor system decrease after considering the seal’s thermal deformation. 展开更多
关键词 High-temperature molten salt pump seal thermal deformation Leakage characteristics seal dynamic characteristics Critical speed
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Double-nylon purse-string suture technique: Another addition to the endoscopist's toolbox for full-thickness defect closure
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作者 Angad Walia Roberto Paolo Trasolini Neal Shahidi 《World Journal of Gastroenterology》 SCIE CAS 2024年第25期3152-3154,共3页
Iatrogenic perforation is the most feared adverse event in endoscopy.With the expansion of interventional endoscopy in favor of traditional surgery,it is now more crucial than ever to develop effective defect closure ... Iatrogenic perforation is the most feared adverse event in endoscopy.With the expansion of interventional endoscopy in favor of traditional surgery,it is now more crucial than ever to develop effective defect closure techniques.This has culminated in the dissemination of multiple novel closure technologies,including through-the-scope clips,over-the-scope clips,through-the-scope suturing and over-the-scope suturing devices.In this editorial,we comment on the recent publication by Wang and colleagues discussing the performance of the double-nylon purse-string suture technique in the closure of large(>3 cm)gastric full-thickness defects.This technique offers a promising,practical and cost-effective approach to closure of large full-thickness defects that can be readily imple-mented across diverse healthcare settings. 展开更多
关键词 Cancer Endoscopy Endoscopic full-thickness resection perforation
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Simple procedure for assessing diffuse subarachnoid hemorrhage successfully created using filament perforation method in mice
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作者 Tatsushi Mutoh Ryota Tochinai +3 位作者 Hiroaki Aono Masayoshi Kuwahara Yasuyuki Taki Tatsuya Ishikawa 《Animal Models and Experimental Medicine》 CAS CSCD 2024年第1期77-81,共5页
The murine model of subarachnoid hemorrhage(SAH)is a valuable experimental tool for investigating molecular and cellular mechanisms,and the endovascular filament perforation technique can be used to simulate prominent... The murine model of subarachnoid hemorrhage(SAH)is a valuable experimental tool for investigating molecular and cellular mechanisms,and the endovascular filament perforation technique can be used to simulate prominent pathophysiological features observed after human SAH;however,current validation methods for assessing an appropriate SAH model are limited.Here,we introduce a simple procedure for se-lecting a mouse model of diffuse SAH.SAH was induced in 24 mice using a standard filament perforation method.After confirming survival at 24 h,SAH was scored 0-1 based on T2*-weighted images on whole-brain magnetic resonance imaging(MRI)and visual surveillance of the cisterna magna(CM)through the dura mater.The CM-based SAH grading correlated well with a reference parameter defined by extracted brain(r^(2)=0.53,p<0.0001).The receiver operating characteristic curve revealed a sensi-tivity of 85%and a specificity of 91%for detecting diffuse SAH,with a similar area under the curve(0.89±0.06[standard error of the mean])as the MRI-based grading(0.72±0.10,p=0.12).Our data suggest that confirming an SAH clot in the CM is a valuable way to select a clinically relevant diffuse SAH model that can be used in future experimental studies. 展开更多
关键词 cisterna magna clot distribution filament perforation mouse model subarachnoid hemorrhage
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