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Lower Bound of Distance Between Unitary Orbits of Normal Elements in C^(*)-algebras of Tracial Rank One
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作者 WANG Ruofei LUO Zheng 《数学进展》 北大核心 2026年第1期171-182,共12页
This paper studies certain estimates for the lower bound of distance between unitary orbits of normal elements.We show that the distance between unitary orbits of normal elements of simple C^(*)-algebras of tracial ra... This paper studies certain estimates for the lower bound of distance between unitary orbits of normal elements.We show that the distance between unitary orbits of normal elements of simple C^(*)-algebras of tracial rank no more than k has a lower bound.Furthermore,if k≤1 and normal elements are commuting,then the lower bound will be better.Another result establishes a connection involving the spectrum distance operator Dc between a C^(*)-algebra of stable rank one C^(*)-algebra and its hereditary C^(*)-subalgebra. 展开更多
关键词 unitary orbit hereditary C^(*)-subalgebra tracial rank one lower bound
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Classification Method of Lower Limbs Motor Imagery Based on Functional Connectivity and Graph Convolutional Network
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作者 Yang Liu Qi Lu +2 位作者 Junjie Wu Huaichang Yin Shiwei Cheng 《Computers, Materials & Continua》 2026年第3期1674-1689,共16页
The development of brain-computer interfaces(BCI)based on motor imagery(MI)has greatly improved patients’quality of life with movement disorders.The classification of upper limb MI has been widely studied and applied... The development of brain-computer interfaces(BCI)based on motor imagery(MI)has greatly improved patients’quality of life with movement disorders.The classification of upper limb MI has been widely studied and applied in many fields,including rehabilitation.However,the physiological representations of left and right lower limb movements are too close and activated deep in the cerebral cortex,making it difficult to distinguish their features.Therefore,classifying lower limbs motor imagery is more challenging.In this study,we propose a feature extraction method based on functional connectivity,which utilizes phase-locked values to construct a functional connectivity matrix as the features of the left and right legs,which can effectively avoid the problem of physiological representations of the left and right lower limbs being too close to each other during movement.In addition,considering the topology and the temporal characteristics of the electroencephalogram(EEG),we designed a temporal-spatial convolutional network(TSGCN)to capture the spatiotemporal information for classification.Experimental results show that the accuracy of the proposed method is higher than that of existing methods,achieving an average classification accuracy of 73.58%on the internal dataset.Finally,this study explains the network mechanism of left and right foot MI from the perspective of graph theoretic features and demonstrates the feasibility of decoding lower limb MI. 展开更多
关键词 Brain-computer interface lower limb motor imagery functional connectivity temporal-spatial convolutional network
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Effect of neurodynamic mobilization on lower limb function in patients with mild post-traumatic knee osteoarthritis
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作者 Jun-Rong Hu Meng-Xiao He +4 位作者 Shan-Shan Wei Han-Wen Ren Cheng-Hao Liu Xiao-Long Liu Zhen-Cheng Chen 《World Journal of Orthopedics》 2026年第1期106-118,共13页
BACKGROUND The therapeutic role of neurodynamic mobilization in improving lower limb function in patients with mild post-traumatic knee osteoarthritis remains poorly understood.AIM To further elucidate the role of neu... BACKGROUND The therapeutic role of neurodynamic mobilization in improving lower limb function in patients with mild post-traumatic knee osteoarthritis remains poorly understood.AIM To further elucidate the role of neurodynamic mobilization in facilitating knee joint functional recovery.METHODS Thirty-two patients with post-traumatic knee osteoarthritis treated at Chonghua Hospital of Traditional Chinese Medicine(Guilin)from March 2024 to August 2025 were randomly assigned to a control group(n=16)or an intervention group(n=16).Both groups received eight weeks of conventional treatment;and the intervention group additionally underwent neurodynamic mobilization.Outcomes including pain assessed by the visual analogue scale,active range of motion,Lysholm score,stork stand test,single hop test,and Y-balance test were assessed before and after the intervention.RESULTS There were no significant differences between the two groups in baseline characteristics,including gender,age,body mass index,or surgical side(P>0.05).Two-way repeated-measures analysis of variance demonstrated significant time×group interaction effects for the visual analogue scale score(F=13.364,P<0.05),Lysholm knee score(F=20.385,P<0.05),stork stand test(F=103.756,P<0.05),and Y-balance test score(F=8.089,P<0.05).CONCLUSION Neurodynamic mobilization effectively reduces pain,improves knee function,and enhances lower limb balance in patients with mild post-traumatic knee osteoarthritis. 展开更多
关键词 Mild post-traumatic knee osteoarthritis Neurodynamic mobilization lower limb function Randomized controlled trial REHABILITATION
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Feasibility of water vapor thermal therapy for treating lower urinary tract symptoms in men with localized prostate cancer on active surveillance:a case series
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作者 Mustufa Babar Farooz Babar +2 位作者 Noah Hawks-Ladds Justin Loloi Michael Ciatto 《The Canadian Journal of Urology》 2026年第1期193-199,共7页
Background:Prostate cancer is a common malignancy,with many men on active surveillance for localized,low-risk disease also experiencing lower urinary tract symptoms(LUTS)from benign prostatic hyperplasia(BPH).Water Va... Background:Prostate cancer is a common malignancy,with many men on active surveillance for localized,low-risk disease also experiencing lower urinary tract symptoms(LUTS)from benign prostatic hyperplasia(BPH).Water Vapor Thermal Therapy(WVTT)is a minimally invasive BPH treatment,but its safety and efficacy in this setting are unclear.Case Description:We report three men with localized PCa on active surveillance who underwent WVTT for LUTS.Conclusions:WVTT appears safe and potentially effective in treating LUTS,especially in those with lower-risk disease and smaller prostate volumes.Further research is needed to confirm safety,efficacy,and optimal patient selection. 展开更多
关键词 lower urinary tract symptoms benign prostatic hyperplasia prostatic neoplasms active surveillance case report
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Deep Learning in Electromyography Signal-based Lower Limb Angle Prediction and Activity Classification
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作者 Gundala Jhansi Rani Mohammad Farukh Hashmi 《Journal of Bionic Engineering》 2026年第1期274-290,共17页
This research presents a Human Lower Limb Activity Recognition(HLLAR)system that identifies specific activities and predicts the angles of the knees simultaneously,based on the EMG signals.The HLLAR systems streamline... This research presents a Human Lower Limb Activity Recognition(HLLAR)system that identifies specific activities and predicts the angles of the knees simultaneously,based on the EMG signals.The HLLAR systems streamlines the research on the lower limb activities.The HILLAR model includes Discrete Hermite Wavelets Transform-based Synchrosqueezing(DHWTS),Deep Two-Layer Multiscale Convolutional Neural Network(DTLMCNN),and Generalized Regression Neural Network(GRNN)as feature extraction,activity recognition,and knee angle prediction respectively.Electromyography signal-based automatic lower limb activity detection is crucial to rehabilitation and human movement analysis.Yet several of these methods face issues in feature extraction in complex data,overlapping signals,extraction of crucial parameters,and adaptation constraints.This research aims classify lower limb activities and predict knee joint angles from electromy-ography signals using HILLAR model.The model is validated on two datasets,comprising 26 subjects performing three classes of activities:walking,standing,and sitting.The proposed model obtained a classification accuracy of 99.95%,along with significant achievements in precision(99.93%),recall(99.91%),and F1-score(99.93%).The generalized regression neural network predicted angles of the knee joint with a root mean squared error of 1.25%.Robustness is demonstrated through consistent results in five-fold cross-validation and statistical significance testing(p-value=0.004,McNemar's test).Additionally,the proposed model showed superior performance over baseline methods by reducing error rates by 18%and decreasing processing time to 0.98 s. 展开更多
关键词 ELECTROMYOGRAPHY lower limb motion recognition Knee joint angle prediction Convolutional neural network Wavelet transform
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Equilibria of the Abstract Economy under Almost Lower Semi-continuous Assumption 被引量:1
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作者 张玉成 陈福川 《Northeastern Mathematical Journal》 CSCD 2003年第1期26-32,共7页
The purpose of this paper is to make a further study on the abstract economy. Here, for the constraint correspondences we assume that they are almost lower semi-continuous (n-lower semi-continuous), which is weaken th... The purpose of this paper is to make a further study on the abstract economy. Here, for the constraint correspondences we assume that they are almost lower semi-continuous (n-lower semi-continuous), which is weaken than that they are lower semi-continuous. Several equilibria existence theorems are proved. 展开更多
关键词 almost lower semi-continuity ε-approximate selection EQUILIBRIUM
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Fuzzy Semi-continuity of fuzzy number-valued function 被引量:3
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作者 Magassy OUS MANE 吴从炘 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2002年第2期139-141,共3页
In this paper we discuss the conecept and property of fuzzy semi continuous function.
关键词 FUZZY NUMBERS FUZZY number-valued FUNCTION FUZZY semi-continuOUS FUNCTION
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Sub-Differential Characterizations of Non-Smooth Lower Semi-Continuous Pseudo-Convex Functions on Real Banach Spaces
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作者 Akachukwu Offia Ugochukwu Osisiogu +4 位作者 Theresa Efor Friday Oyakhire Monday Ekhator Friday Nkume Sunday Aloke 《Open Journal of Optimization》 2023年第3期99-108,共10页
In this paper, we characterize lower semi-continuous pseudo-convex functions f : X → R ∪ {+ ∞} on convex subset of real Banach spaces K  ⊂ X with respect to the pseudo-monotonicity of its Clarke-Rockafellar Su... In this paper, we characterize lower semi-continuous pseudo-convex functions f : X → R ∪ {+ ∞} on convex subset of real Banach spaces K  ⊂ X with respect to the pseudo-monotonicity of its Clarke-Rockafellar Sub-differential. We extend the results on the characterizations of non-smooth convex functions f : X → R ∪ {+ ∞} on convex subset of real Banach spaces K  ⊂ X with respect to the monotonicity of its sub-differentials to the lower semi-continuous pseudo-convex functions on real Banach spaces. 展开更多
关键词 Real Banach Spaces Pseudo-Convex Functions Pseudo-Monotone Maps Sub-Differentials lower semi-continuous Functions and Approximate Mean Value Inequality
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Upper semi-continuity of attractors for multivalued semi-flow under random perturbation
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作者 李挺 刘曾荣 《Journal of Shanghai University(English Edition)》 CAS 2006年第4期288-292,共5页
In this paper the upper semi-continuity of global attractors for multivalued semi-flows under random perturbation was studied. First, the existence of random attractors for multivalued random semi-flows was considered... In this paper the upper semi-continuity of global attractors for multivalued semi-flows under random perturbation was studied. First, the existence of random attractors for multivalued random semi-flows was considered, then it was proved that the global attractors for multivalue semi-flows are the upper semi-continuity under random perturbation. This result can be used in the numerical approximation of multivalued semi-flows and non-autonomous perturbation of multivalued semi-flows. 展开更多
关键词 random attractor upper semi-continuity absorbing set.
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Existence and Upper Semi-Continuity of Random Attractors for Nonclassical Diffusion Equation with Multiplicative Noise on Rn
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作者 Fadlallah Mustafa Mosa Abdelmajid Ali Dafallah +2 位作者 Qiaozhen Ma Eshag Mohamed Ahmed Mohamed Y. A. Bakhet 《Journal of Applied Mathematics and Physics》 2022年第12期3898-3919,共22页
This paper is concerned with the existence and upper semi-continuity of random attractors for the nonclassical diffusion equation with arbitrary polynomial growth nonlinearity and multiplicative noise in H<sup>1... This paper is concerned with the existence and upper semi-continuity of random attractors for the nonclassical diffusion equation with arbitrary polynomial growth nonlinearity and multiplicative noise in H<sup>1</sup>(R<sup>n</sup>). First, we study the existence and uniqueness of solutions by a noise arising in a continuous random dynamical system and the asymptotic compactness is established by using uniform tail estimate technique, and then the existence of random attractors for the nonclassical diffusion equation with arbitrary polynomial growth nonlinearity. As a motivation of our results, we prove an existence and upper semi-continuity of random attractors with respect to the nonlinearity that enters the system together with the noise. 展开更多
关键词 Random Attractors Nonclassical Diffusion Equations Asymptotic Compactness Upper semi-continuity
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Forecast of the Burden of Lower Respiratory Infections in the Elderly Aged 70 and above in China from 1990 to 2050,GBD2021 被引量:1
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作者 Miaomiao Zhang Ruiyi Zhang +1 位作者 Yuchang Zhou Maigeng Zhou 《Biomedical and Environmental Sciences》 2025年第5期539-546,共8页
Objective This study aims to analyze the burden of lower respiratory infections in Chinese elderly people aged 70 and above.Methods This study utilized Global Burden of Disease(GBD)1990-2050 prediction data to analyze... Objective This study aims to analyze the burden of lower respiratory infections in Chinese elderly people aged 70 and above.Methods This study utilized Global Burden of Disease(GBD)1990-2050 prediction data to analyze changes in mortality rates and disability-adjusted life year(DALY)rates for lower respiratory infections in the elderly population(aged 70 and above)in China from 1990 to 2050.It also discusses future trends in the burden of lower respiratory infections(LRI)in China under different scenarios.Results According to GBD predictions,the burden of lower respiratory infections in the elderly aged 70 years and above in China is lower than the global average.The burden has been decreasing from 1990 to 2020,but is projected to increase from 2020 to 2050.Scenario-based predictions suggest that,under scenarios involving improvements in nutrition and vaccination,the burden of lower respiratory infections in the elderly in China is expected to be the lowest in 2050.Conclusion This study indicates that the burden of lower respiratory infections in elderly people aged 70 years and above in China remains a significant public health issue and may worsen.The government should consider strengthening the preventive measures and management strategies for respiratory infections in the elderly population. 展开更多
关键词 lower respiratory infections China Mortality rate Trends DALY
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Climate aridification and intensified human interference undermined water storage in the Lower Yellow River region 被引量:1
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作者 Xilin Wu Xiaoming Feng Bojie Fu 《Geography and Sustainability》 2025年第4期246-256,共11页
Understanding the relationships between human activities and hydrological processes is critical for sustainable water resources management, especially under the threat of increasing climate extremes. China's Lower... Understanding the relationships between human activities and hydrological processes is critical for sustainable water resources management, especially under the threat of increasing climate extremes. China's Lower Yellow River(LYR) region is one of the world's most water-scarce and human-impacted areas, yet comprehensive information on its water resources is lacking. This study adopted a water resources system(WRS) analytical framework to investigate the water crisis facing the region. The findings reveal that over the last decade, the system's resilience has been undermined by the combined impacts of climate aridification and intensified human interference. Specifically, a delicate balance between natural groundwater depletion and irrigation replenishment has been disrupted by a series of drought events since 2012. Increased groundwater extraction during droughts, coupled with an imbalanced allocation of surface water resources, has led to a persistent decline in water storage that has continued even after the droughts have ended. To mitigate future climate risks in the LYR,we recommend implementing more adaptive strategies, such as flexible water regulation policies and combined surface-groundwater management. Lessons from the LYR have important implications for other regions facing water resource challenges. 展开更多
关键词 Water resources system lower Yellow River GROUNDWATER Socio-hydrology Sustainable water management
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Peroral endoscopic myotomy for achalasia and patients with normal lower-esophageal-sphincter integrated relaxation pressure:A propensity-score-matched retrospective study 被引量:1
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作者 Xiao Li Xiao-Bin Zhang +9 位作者 Jia-Kang Shao Bo Zhang Long-Song Li Rui-Qing Zhu Jia-Le Zou Jia-Feng Wang Xin Zhao Qing-Zhen Wu Ning-Li Chai En-Qiang Linghu 《World Journal of Gastroenterology》 2025年第12期27-36,共10页
BACKGROUND Most patients who were included in previous studies on achalasia had increased lower esophageal sphincter(LES)pressure.Peroral endoscopic myotomy(POEM)has been confirmed to be effective at relieving the cli... BACKGROUND Most patients who were included in previous studies on achalasia had increased lower esophageal sphincter(LES)pressure.Peroral endoscopic myotomy(POEM)has been confirmed to be effective at relieving the clinical symptoms of achalasia associated with increased LES pressure.AIM To identify the safety and efficacy of POEM for patients with normal LES integrated relaxation pressure(LES-IRP).METHODS The clinical data of patients who underwent POEM successfully in The First Medical Center of Chinese PLA General Hospital were retrospectively analyzed.A total of 481 patients who underwent preoperative high-resolution manometry(HRM)at our hospital were ultimately included in this research.According to the HRM results,the patients were divided into two groups:71 patients were included in the normal LES-IRP group(LES-IRP<15 mmHg)and 410 patients were included in the increased LES-IRP group(LES-IRP≥15 mmHg).Clinical characteristics,procedure-related parameters,adverse events,and outcomes were compared between the two groups to evaluate the safety and efficacy of POEM for patients with normal LES-IRP.RESULTS Among the 481 patients included in our study,209 were males and 272 were females,with a mean age of 44.2 years.All patients underwent POEM without severe adverse events.The median pre-treatment Eckardt scores of the normal LES-IRP and increased LES-IRP groups were 7.0 and 7.0(P=0.132),respectively,decreasing to 1.0 and 1.0 post-treatment(P=0.572).The clinical success rate of the normal LES-IRP group was 87.3%(62/71),and that of the increased LES-IRP group was 91.2%(374/410)(P=0.298).Reflux symptoms were measured by the GerdQ questionnaire,and the percentages of patients with GerdQ scores≥9 in the normal LES-IRP and increased LES-IRP groups were 8.5%and 10.7%,respectively(P=0.711).After matching,the rates of clinical success and the rates of GerdQ score≥9 were not significantly different between the two groups.CONCLUSION Our results suggest that POEM is safe and effective for achalasia and patients with normal LES-IRP.In addition,in patients with normal LES-IRP,compared with those with increased LES-IRP,POEM was not associated with a greater incidence of reflux symptoms. 展开更多
关键词 Peroral endoscopic myotomy ACHALASIA lower esophageal sphincter integrated relaxation pressure Safety Efficacy
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Foreign Bodies in the Lower Airways: Patient Pathways and Management at the ENT Department of Donka National Hospital, Guinea
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作者 Ibrahima Diallo Mamadou Mouctar Ramata Diallo +13 位作者 Ismaël Dabo Sayon Kourouma Mamadou Aliou Diallo Alseny Camara Alseny Cissé Raphan Mady Kaba Keïta Aminata G. Diallo Mamadou Cellou Bah Youssouf Bapaté Barry Alpha Oumar Barry Abdoulaye Bayo Mohamed Casimir Kaman Abdoulaye Keita Alpha Oumar Diallo 《International Journal of Otolaryngology and Head & Neck Surgery》 2025年第1期39-46,共8页
Introduction: Foreign bodies (FB) in the lower airways (LAs) constitute a potentially life-threatening emergency requiring immediate management. The objective of our study was to describe the patient pathway and manag... Introduction: Foreign bodies (FB) in the lower airways (LAs) constitute a potentially life-threatening emergency requiring immediate management. The objective of our study was to describe the patient pathway and management of foreign bodies in the lower airways. Methodology: This was a descriptive study with retrospective data collection conducted over a 6-year period (January 1, 2014, to December 31, 2019) in the ENT and Head and Neck Surgery Department of Donka National Hospital. Results: We observed a prevalence of 1.79%. The average age was 5.71 years, with a sex ratio of 1.2. However, 82.61% of the cases originated from rural areas. We noted that 78.83% of patients were referred after visiting 1 to 2 healthcare facilities (75.36%). The consultation delay was 3 days. Penetration syndrome was present in 98.56% of cases. The foreign body incidents occurred during play in 54.84% and during meals in 29.09% of cases. Radiographs were performed in 93.9% of cases. Endoscopy was used for both diagnostic and therapeutic purposes in all patients. The foreign bodies were located in the trachea (37.68%), larynx (26.08%), and bronchi (21.73%). Non-organic foreign bodies were predominant (52.17%). Postoperative outcomes were uncomplicated in 95.98% of cases, and the lethality rate was 2.85%. Conclusion: The pathway of patients with foreign bodies in the airways remains unpredictable in our context due to parental hesitations. Early management reduces morbidity and mortality rates. 展开更多
关键词 PATHWAY Foreign Bodies lower Airways Treatment GUINEA
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Surgical Management of Varicose Veins of the Lower Limbs: Retrospective Study of 280 Patients
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作者 Papa Amath Diagne Abdoul Aziz Thiaw +14 位作者 Momar Sokhna Diop Ndeye Fatou Sow Abdoul Ahad Mbengue Papa Ousmane Ba Mory Camara Soda Mareme Mbaye Moussa Seck Diop Jean Claude Dione Abdoul Khoudoss Diallo Moussa Mareme Samba Ibrahima Wade Anta Mbaye Sall Magaye Gaye Papa Adama Dieng Amadou Gabriel Ciss 《Surgical Science》 2025年第2期110-114,共5页
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
关键词 Varicose Veins lower Limbs STRIPPING
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Open Lower Limb Trauma in Children
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作者 Abakar Djibrine Mahamat-Nour Olivier N’garinguem +3 位作者 Bembo Lamega Ali Haouane Nazira Kalki Djiannone Ouchemi Choua 《Open Journal of Orthopedics》 2025年第2期110-116,共7页
Purpose: To evaluate open lower limb trauma management in children. Me-thod: We conducted a twelve-month cross-sectional prospective study. Results: Open trauma of lower limb had 7.9% of hospital frequency. Mean age w... Purpose: To evaluate open lower limb trauma management in children. Me-thod: We conducted a twelve-month cross-sectional prospective study. Results: Open trauma of lower limb had 7.9% of hospital frequency. Mean age was 8 years with a sex ratio of 2.45. In 68.4% of cases, trauma occurred in road traffic accidents. Average consultation time was 2.4 hours. Trauma mainly affected the leg in 39.5% of cases, and the thigh in 34.2%. Soft tissue wounds occurred in 52.6% of cases, and open fractures in 47.4%. Average response time was one hour. Wound trimming and suturing were performed in 76.3% of cases and combined with bone nailing in 15.8%. The outcome was favorable in 92.1% of cases. Average hospital stay was 4.37 days. Conclusion: Open trauma to the lower limb is a frequent and occurs mainly in road traffic accidents. Management was early, with a favorable outcome for most patients and a short hospital stay. 展开更多
关键词 Open Trauma Open Fractures lower Limb CHILDREN CHUME CHAD
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Sarcopterygians from the Lochkovian(Lower Devonian)of Nanning,Guangxi,China
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作者 LI Mao-Kun CUI Xin-Dong +1 位作者 ZHU Min QIAO Tuo 《古脊椎动物学报(中英文)》 北大核心 2025年第1期1-19,共19页
Here we report a left cheek plate of Psarolepis,a postparietal shield of Youngolepis,a skull of Diabolepis,and a scale of Styloichthys from the Lianhuashan and Nahkaoling formations(Lochkovian,Lower Devonian)of Nannin... Here we report a left cheek plate of Psarolepis,a postparietal shield of Youngolepis,a skull of Diabolepis,and a scale of Styloichthys from the Lianhuashan and Nahkaoling formations(Lochkovian,Lower Devonian)of Nanning,Guangxi.This marks the first report of Diabolepis and Styloichthys beside Qujing,Yunnan,and the latest occurrence of Psarolepis to date.The fossil community displays significant similarities to the Xujiachong Assemblage,and provides new data for the Lower Devonian stratigraphic correlation between southwestern China and northern Vietnam.Given the latest dating constraint based on the conodont evidence,we regard that the Xujiachong Assemblage has a much longer range than previously supposed,extending from the latest Lochkovian to the end of Pragian.We propose that the transition of the Nahkaoling and Lianhuashan formations in Nanning might correspond to the Guijiatun Formation in Qujing.The relatively large size of fish individuals from Guangxi is probably attributed to the increase in the oxygen content of the ocean. 展开更多
关键词 Nanning Guangxi Lochkovian lower Devonian Xujiachong Assemblage Lianhuashan Formation Nahkaoling Formation Sarcopterygians
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Impact of TiC particles on microstructure and properties of Al-Cu-Mn alloys by semi-continuous casting
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作者 Gao-song Wang Sheng-xiao Zhou +4 位作者 Zhi-yu Gao Tao Zheng Da Xu Wen-tao Sun Zai-hong Wang 《China Foundry》 2025年第6期603-614,共12页
Al-based TiC particle-reinforced composites with varying TiC concentrations were fabricated through semi-continuous casting.The effects of TiC particles on the alloys’microstructure,grain boundary segregation,and mec... Al-based TiC particle-reinforced composites with varying TiC concentrations were fabricated through semi-continuous casting.The effects of TiC particles on the alloys’microstructure,grain boundary segregation,and mechanical properties were systematically analyzed.Moreover,the mechanisms by which TiC particles contribute to grain refinement,suppression of grain boundary segregation,and enhancement of hardness and wear resistance were discussed.The results demonstrate that TiC particles act as heterogeneous nucleation sites forα-Al within the Al-Cu-Mn alloys,leading to a refinement of grain size.As the TiC particle’s content increases,the grain size of the alloy drops at first and then elevates,transitioning from coarse dendritic crystals to fine equiaxed grains.At a TiC content of 1.3wt.%,the alloy exhibits the smallest grain size,reducing from 139±42μm without TiC to 90±38μm.Beyond this concentration,grain coarsening is observed.The incorporation of TiC particles effectively mitigates Cu segregation at grain boundaries,thereby enhancing the homogeneity of the Al-Cu-Mn matrix alloys.Additionally,the addition of TiC particles promotes hardness and wear resistance.Both hardness and wear resistance exhibit an initial increase followed by a decrease with increasing TiC content from 0 to 1.8wt.%. 展开更多
关键词 TiC particle Al-Cu-Mn-based composites grain refinement semi-continuous casting wear resistance
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Shale gas prospect of the Lower Permian in the South Yellow Sea Basin of the Lower Yangtze area: Insights from the whole-cored CSDP-2 borehole
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作者 Yu-mao Pang Zhao-meng Wei +3 位作者 Xing-wei Guo Chuan-sheng Yang Rui-shan Ma Xun-hua Zhang 《China Geology》 2025年第4期707-724,共18页
Shale gas is abundant in the Paleozoic of the Yangtze Platform,and several high-yield shale gas fields have been built in the Upper Yangtze Platform,China.The Permian of the South Yellow Sea Basin(SYSB)in the Lower Ya... Shale gas is abundant in the Paleozoic of the Yangtze Platform,and several high-yield shale gas fields have been built in the Upper Yangtze Platform,China.The Permian of the South Yellow Sea Basin(SYSB)in the Lower Yangtze area is considered a potential target for shale gas exploration;however,the fundamental geological conditions of shale gas have not been studied.Based on the first whole-cored scientific drilling borehole(CSDP-2)in the SYSB,detailed tests involving petrology,organic geochemistry,and reservoir physical properties were conducted to evaluate the shale gas potential of the Lower Permian.The Lower Permian is dominated by organic-rich siliceous,clay,and clay-mixed shales.The average total organic carbon content is 5.99%,and the organic matter is mainly type Ⅱ_(1)−Ⅱ_(2),which has entered the high-over mature evolution stage.The pore types of organic-rich shales mainly include organic pores,dissolution pores,and intergranular pores,of which the meso-/macropores are well developed.The average porosity is 3.04%,and the total specific surface area and pore volume are 3.47 m^(2)/g and 7.21×10^(−3) cm^(3)/g,respectively.The average Langmuir volume obtained from the methane adsorption isotherms is 2.70 cm^(3)/g,and methane is mainly adsorbed in the meso-/macropores.The lower Permian shales are rich in methane as indicated by gas logging results,with an average content of 7.3%,which can reach up to 65.9%.A comparison of the study area with typical shale gas fields shows that the Lower Permian is brittle and shallowly buried and has a high potential for shale gas exploration and low-cost development.The depression areas of the SYSB are overlain by thick Mesozoic-Cenozoic sediments,show higher organic matter maturity,and may have greater shale gas potential.The shale gas exploration breakthrough of the study area is of great significance to ensure the energy supply of economically developed areas on the east China. 展开更多
关键词 Shale gas Continental Shelf Drilling Program South Yellow Sea Basin lower Yangtze Platform lower Permian Shale reservoir evaluation Oil-gas exploration engineering
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Unmasking frailty in coronary artery disease:impact on outcomes after lower limb amputation
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作者 Abdul Rasheed Bahar Yasemin Bahar +7 位作者 Busra Cangut Paawanjot Kaur Vaishnavi Sirekulam Mohamad Hasan Jawadi Naveed Tarar Mohamed Saleh Alrayyashi Olayiwola Bolaji M.Chadi Alraies 《Journal of Geriatric Cardiology》 2025年第11期900-910,共11页
Background Frailty is a major determinant of outcomes in patients with coronary artery disease(CAD)undergoing lower limb amputation.This study evaluates the impact of frailty on in-hospital outcomes in these patients.... Background Frailty is a major determinant of outcomes in patients with coronary artery disease(CAD)undergoing lower limb amputation.This study evaluates the impact of frailty on in-hospital outcomes in these patients.Methods We performed a retrospective analysis of the National Inpatient Sample(2016–2021)to identify adult patients with CAD who underwent lower limb amputation.Frailty was defined using the Johns Hopkins Adjusted Clinical Groups(ACG)frailty indicator.Multivariable logistic regression was used to assess the independent association of frailty with in-hospital outcomes,and propensity score matching(PSM)was performed to further account for confounding factors.Results After PSM,9,990 patients were included in each cohort.Frail patients experienced higher rates of in-hospital mortality(3.9%vs.1.5%,P<0.001),acute limb ischemia(3.8%vs.3.1%,P=0.015),fasciotomy(2.1%vs.1.4%,P<0.001),stump infection(7.9%vs.6.6%,P<0.001),cardiogenic shock(0.9%vs.0.7%,P=0.032),sudden cardiac arrest(2.7%vs.2.1%,P=0.004),mechanical circulatory support(0.3%vs.0.2%,P=0.028),major adverse cardiac and cerebrovascular events(7.7%vs.5.4%,P<0.001),and sepsis(18.3%vs.13.8%,P<0.001).In multivariable logistic regression analysis,frailty remained an independent predictor of inhospital mortality and major complications.Conclusion Frailty is independently associated with increased in-hospital mortality and adverse events among CAD patients undergoing lower limb amputation.Incorporating frailty assessment into preoperative evaluation may improve risk stratification and guide clinical decision-making in this high-risk population. 展开更多
关键词 FRAILTY propensity score matching coronary artery disease hospital outcomes lower limb amputation coronary artery disease cad undergoing logistic regression lower limb amputationfrailty
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