While endoscopic retrograde cholangiopancreatography(ERCP)remains the primary treatment modality for common bile duct stones(CBDS)or choledocho-lithiasis due to advancements in instruments,surgical intervention,known ...While endoscopic retrograde cholangiopancreatography(ERCP)remains the primary treatment modality for common bile duct stones(CBDS)or choledocho-lithiasis due to advancements in instruments,surgical intervention,known as common bile duct exploration(CBDE),is still necessary in cases of difficult CBDS,failed endoscopic treatment,or altered anatomy.Recent evidence also supports CBDE in patients requesting single-step cholecystectomy and bile duct stone removal with comparable outcomes.This review elucidates relevant clinical anatomy,selection indications,and outcomes to enhance surgical understanding.The selection between trans-cystic(TC)vs trans-choledochal(TD)approaches is described,along with stone removal techniques and ductal closure.Detailed surgical techniques and strategies for both the TC and TD approaches,including instrument selection,is also provided.Additionally,this review comprehensively addresses operation-specific complications such as bile leakage,stricture,and entrapment,and focuses on preventive measures and treatment strategies.This review aims to optimize the management of CBDS through laparoscopic CBDE,with the goal of improving patient outcomes and minimizing risks.展开更多
In this paper,we present a distal-scanning common path probe for optical coherence tomography(OCT)equipped with a hollow ultrasonic motor and a simple and specially designed beam-splitter.This novel probe proves to be...In this paper,we present a distal-scanning common path probe for optical coherence tomography(OCT)equipped with a hollow ultrasonic motor and a simple and specially designed beam-splitter.This novel probe proves to be able to effectively circumvent polarization and dispersion mismatch caused by fiber motion and is more robust to a variety of interfering factors during the imaging process,experimentally compared to a conventional noncommon path probe.Furthermore,our design counteracts the attenuation of backscattering with depth and the fall-off of the signal,resulting in a more balanced signal range and greater imaging depth.Spectral-domain OCT imaging of phantom and biological tissue is also demonstrated with a sensitivity of∼100dB and a lateral resolution of∼3μm.This low-cost probe offers simplified system configuration and excellent robustness,and is therefore particularly suitable for clinical diagnosis as one-off medical apparatus.展开更多
Introduction: In Cameroon, surgery remains the only approach in malignant obstructions of the common bile duct (MOCBD) even in palliative situations. The aim of this work was to describe the modalities of surgical tre...Introduction: In Cameroon, surgery remains the only approach in malignant obstructions of the common bile duct (MOCBD) even in palliative situations. The aim of this work was to describe the modalities of surgical treatment of MOCBD, evaluate the results and detect the factors associated with postoperative morbidity and mortality. Patients and Methods: We conducted an analytical observational study, with retrospective data collection from the files of patients operated upon for MOCBD. This was done in four referral hospitals in the city of Yaoundé for a 42-month period spanning from January 1, 2020 to June 30, 2023. Demographic data, clinical presentation, surgical data, and 30-day postoperative outcomes were collected. Results: We collected 71 files. The sex ratio was 1.4 and the mean age was 56 ± 11 years. Fifty-three (53) patients (74.6%) were overweight or obese and 10 patients (14.1%) were hypertensive. A clinical cholestasis syndrome was present in 69 patients (97.2%). Fifty-five (55) patients (77.5%) had a cancer of the head of the pancreas, 8 patients (11.3%) had an extra-hepatic cholangiocarcinoma and 8 patients (11.3%) had an ampullary adenocarcinoma. Eight (8) resections (11.3%) with curative intent had been carried out and in 63 cases (88.7%), surgery was palliative. Postoperative morbidity was 55.7%, influenced by advanced WHO stage (p = 0.02). Postoperative mortality was 25.7%, associated with a high ASA score (p = 0.01). Conclusion: Pancreatic head cancer is the main etiology of malignant obstructions of the common bile duct in Cameroon. Surgical treatment is most often palliative. Postoperative morbidity and mortality are high, influenced by high WHO and ASA scores.展开更多
Here,a nonhydrostatic alternative scheme(NAS)is proposed for the grey zone where the nonhydrostatic impact on the atmosphere is evident but not large enough to justify the necessity to include an implicit nonhydrostat...Here,a nonhydrostatic alternative scheme(NAS)is proposed for the grey zone where the nonhydrostatic impact on the atmosphere is evident but not large enough to justify the necessity to include an implicit nonhydrostatic solver in an atmospheric dynamical core.The NAS is designed to replace this solver,which can be incorporated into any hydrostatic models so that existing well-developed hydrostatic models can effectively serve for a longer time.Recent advances in machine learning(ML)provide a potential tool for capturing the main complicated nonlinear-nonhydrostatic relationship.In this study,an ML approach called a neural network(NN)was adopted to select leading input features and develop the NAS.The NNs were trained and evaluated with 12-day simulation results of dry baroclinic-wave tests by the Weather Research and Forecasting(WRF)model.The forward time difference of the nonhydrostatic tendency was used as the target variable,and the five selected features were the nonhydrostatic tendency at the last time step,and four hydrostatic variables at the current step including geopotential height,pressure in two different forms,and potential temperature,respectively.Finally,a practical NAS was developed with these features and trained layer by layer at a 20-km horizontal resolution,which can accurately reproduce the temporal variation and vertical distribution of the nonhydrostatic tendency.Corrected by the NN-based NAS,the improved hydrostatic solver at different horizontal resolutions can run stably for at least one month and effectively reduce most of the nonhydrostatic errors in terms of system bias,anomaly root-mean-square error,and the error of the wave spatial pattern,which proves the feasibility and superiority of this scheme.展开更多
Many networks exhibit the core/periphery structure.Core/periphery structure is a type of meso-scale structure that consists of densely connected core nodes and sparsely connected peripheral nodes.Core nodes tend to be...Many networks exhibit the core/periphery structure.Core/periphery structure is a type of meso-scale structure that consists of densely connected core nodes and sparsely connected peripheral nodes.Core nodes tend to be well-connected,both among themselves and to peripheral nodes,which tend not to be well-connected to other nodes.In this brief report,we propose a new method to detect the core of a network by the centrality of each node.It is discovered that such nodes with non-negative centralities often consist in the core of the networks.The simulation is carried out on different real networks.The results are checked by the objective function.The checked results may show the effectiveness of the simulation results by the centralities of the nodes on the real networks.Furthermore,we discuss the characters of networks with the single core/periphery structure and point out the scope of the application of our method at the end of this paper.展开更多
Manganese-based perovskite is popular for research on ferromagnetic materials,and its spectroscopic studies are essential for understanding its electronic structure,dielectric,electrical,and magnetic properties.In thi...Manganese-based perovskite is popular for research on ferromagnetic materials,and its spectroscopic studies are essential for understanding its electronic structure,dielectric,electrical,and magnetic properties.In this paper,the M-edge spectra of La ions and the M-edge,L-edge,and K-edge spectra of Mn ions in LaMnO3 are calculated by considering both the free-ion multiplet calculation and the crystal field effects.We analyze spectral shapes,identify peak origins,and estimate the oxidation states of La and Mn ions in LaMnO3 theoretically.It is concluded that La ions in LaMnO3 predominantly exist in the trivalent state,while Mn ions exist primarily in the trivalent state with a minor presence of tetravalent ions.Furthermore,the calculated spectra are in better conformity with the experimental spectra when the proportion of Mn3+is 90%and Mn4+is 10%.This article enhances our comprehension of the oxidation states of La and Mn within the crystal and also provides a valuable guidance for spectroscopic investigations of other manganates.展开更多
Under the historical background of promoting agricultural and rural modernization in an all-round way,this paper deeply analyzes the practical significance of digital construction in rural China,and explores the probl...Under the historical background of promoting agricultural and rural modernization in an all-round way,this paper deeply analyzes the practical significance of digital construction in rural China,and explores the problems in the digitalization level of rural infrastructure,farmers digitalization awareness and accomplishment,and agricultural digital system.Countermeasures and suggestions are put forward from four aspects:digital village construction policy system,rural digital infrastructure construction,rural digital talent cultivation system,and agricultural digital system,and the rural digital construction of Huzhou City is taken as an example,in order to further realize the goal of empowering rural farmers with digital technology for common prosperity.展开更多
Curcumin is a natural polyphenol that is used in various traditional medicines.However,its inherent properties,such as its rapid degradation and metabolism,low bioavailability,and short half-life,are serious problems ...Curcumin is a natural polyphenol that is used in various traditional medicines.However,its inherent properties,such as its rapid degradation and metabolism,low bioavailability,and short half-life,are serious problems that must be resolved.To this end,a drug carrier incorporating natural magnetic cores in a zeolite framework was developed and applied to the loading of curcumin in ethanol solutions.In this system,curcumin is encapsulated in a zeolite Na(ZNA)magnetic core–shell structure(Fe@Si/ZNA),which can be easily synthesized using an in situ method.Synthesis of Fe_(3)O_(4) nanoparticles was carried out from natural materials using a co-precipitation method.Analysis of the prepared magnetic core–shell structures and composites was carried out using vibrating-sample magnetometery,Fourier transform infrared spectroscopy,transmission electron microscopy,and x-ray diffraction.The cumulative loading of curcumin in the ZNA composite with 9%nanoparticles was found to reach 90.70%with a relatively long half-life of 32.49 min.Stability tests of curcumin loading in the composite showed that adding magnetic particles to the zeolite framework also increased the stability of the composite structure.Adsorption kinetics and isotherm studies also found that the system follows the pseudo-second-order and Langmuir isotherm models.展开更多
The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around...The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around the rotation axis of the spinning Earth during the growth of the core the rotation should have been accelerated. Controversially the tidal dissipation by the Moon, which is mainly dependent on the availability of open shallow seas and the kind of Moon escape from a nearby position, acts towards a deceleration of the rotating Earth. Measurements of LOD for Phanerozoic and Precambrian times open ways to solve questions concerning the geodynamical history of the Earth. These measurements encompass investigations of growth patterns in fossils and depositional patterns in sediments (Cyclostratigraphy, Tidalites, Stromatolites, Rhythmites). These patterns contain information on the LOD and on the changing distance between Earth and Moon and can be used as well for a discussion about the growth of the Earth’s core. By updating an older paper with its simple approach as well as incorporating newly published results provided by the geoscientific community, a moderate to fast growth of the core in a hot early Earth will be favored controversially to the assumption of a delayed development of the core in an originally cold Earth. Core development with acceleration of Earth’s rotation and the contemporaneous slowing down due to tidal dissipation during the filling of the ocean may significantly interrelate.展开更多
The Earth’s Free Core Nutation(FCN) causes Earth tides and forced nutation with frequencies close to the FCN that exhibit resonance effects.High-precision superconducting gravimeter(SG) and very long baseline interfe...The Earth’s Free Core Nutation(FCN) causes Earth tides and forced nutation with frequencies close to the FCN that exhibit resonance effects.High-precision superconducting gravimeter(SG) and very long baseline interferometry(VLBI) provide good observation techniques for detecting the FCN parameters.However,some choices in data processing and solution procedures increase the uncertainty of the FCN parameters.In this study,we analyzed the differences and the effectiveness of weight function and ocean tide corrections in the FCN parameter detection using synthetic data,SG data from thirty-one stations,and the 10 celestial pole offset(CPO) series.The results show that significant discrepancies are caused by different computing options for a single SG station.The stacking method,which results in a variation of0.24-5 sidereal days(SDs) in the FCN period(T) and 10^(3)-10^(4) in the quality factor(Q) due to the selection of the weighting function and the ocean tide model(OTM),can effectively suppress this influence.The statistical analysis results of synthetic data shows that although different weight choices,while adjusting the proportion of diurnal tidal waves involved,do not significantly improve the accuracy of fitted FCN parameters from gravity observations.The study evaluated a series of OTMs using the loading correction efficiency.The fitting of FCN parameters can be improved by selecting the mean of appropriate OTMs based on the evaluation results.Through the estimation of the FCN parameters based on the forced nutation,it was found that the weight function P_(1) is more suitable than others,and different CPO series(after 2009) resulted in a difference of 0.4 SDs in the T and of 103 in the Q.We estimated the FCN parameters for SG(T=430.4±1.5 SDs and Q=1.52×10^(4)±2.5×10^(3)) and for VLBI(T=429.8±0.7 SDs,Q=1.88×10^(4)±2.1×10^(3)).展开更多
BACKGROUND Undifferentiated pleomorphic sarcoma(UPS)is a rare malignant mesenchymal tumor with a poor prognosis.It mainly occurs in the extremities,trunk,head and neck,and retroperitoneum regions.Owing to the lack of ...BACKGROUND Undifferentiated pleomorphic sarcoma(UPS)is a rare malignant mesenchymal tumor with a poor prognosis.It mainly occurs in the extremities,trunk,head and neck,and retroperitoneum regions.Owing to the lack of specific clinical manifestations and imaging features,UPS diagnosis mainly depends on pathological and immunohistochemical examinations for exclusive diagnosis.Here we report an extremely rare case of high-grade UPS in the common bile duct(CBD).There are limited available data on such cases.CASE SUMMARY A 70-year-old woman was admitted to our department with yellow eyes and urine accompanied by upper abdominal distending pain for 2 wk.Her laboratory data suggested significantly elevated hepatorenal function levels.The imaging data revealed calculous cholecystitis,intrahepatic and extrahepatic bile duct dilation with extrahepatic bile duct calculi,and a space-occupying lesion at the distal CBD.After endoscopic biliary stenting and symptomatic support therapy,CBD exploration and biopsy were performed.The frozen section indicated malignant spindle cell tumor of the CBD mass,and further radical pancreaticoduodenectomy was performed.Finally,the neoplasm was diagnosed as a high-grade UPS combined with the light-microscopic morphology and immunohistochemical results.CONCLUSION This extremely rare case highlighted the need for increasing physicians'vigilance,reducing the odds of misdiagnosis,and providing appropriate treatment strategies.展开更多
Large Language Models (LLMs) have revolutionized Generative Artificial Intelligence (GenAI) tasks, becoming an integral part of various applications in society, including text generation, translation, summarization, a...Large Language Models (LLMs) have revolutionized Generative Artificial Intelligence (GenAI) tasks, becoming an integral part of various applications in society, including text generation, translation, summarization, and more. However, their widespread usage emphasizes the critical need to enhance their security posture to ensure the integrity and reliability of their outputs and minimize harmful effects. Prompt injections and training data poisoning attacks are two of the most prominent vulnerabilities in LLMs, which could potentially lead to unpredictable and undesirable behaviors, such as biased outputs, misinformation propagation, and even malicious content generation. The Common Vulnerability Scoring System (CVSS) framework provides a standardized approach to capturing the principal characteristics of vulnerabilities, facilitating a deeper understanding of their severity within the security and AI communities. By extending the current CVSS framework, we generate scores for these vulnerabilities such that organizations can prioritize mitigation efforts, allocate resources effectively, and implement targeted security measures to defend against potential risks.展开更多
This study aims to thoroughly investigate the axial power peaking factors (PPF) within the low-enriched uranium (LEU) core of the Ghana Research Reactor-1 (GHARR-1). This study uses advanced simulation tools, like the...This study aims to thoroughly investigate the axial power peaking factors (PPF) within the low-enriched uranium (LEU) core of the Ghana Research Reactor-1 (GHARR-1). This study uses advanced simulation tools, like the MCNPX code for analysing neutron behavior and the PARET/ANL code for understanding power variations, to get a clearer picture of the reactor’s performance. The analysis covers the initial six years of GHARR-1’s operation and includes projections for its whole 60-year lifespan. We closely observed the patterns of both the highest and average PPFs at 21 axial nodes, with measurements taken every ten years. The findings of this study reveal important patterns in power distribution within the core, which are essential for improving the safety regulations and fuel management techniques of the reactor. We provide a meticulous approach, extensive data, and an analysis of the findings, highlighting the significance of continuous monitoring and analysis for proactive management of nuclear reactors. The findings of this study not only enhance our comprehension of nuclear reactor safety but also carry significant ramifications for sustainable energy progress in Ghana and the wider global context. Nuclear engineering is essential in tackling global concerns, such as the demand for clean and dependable energy sources. Research on optimising nuclear reactors, particularly in terms of safety and efficiency, is crucial for the ongoing advancement and acceptance of nuclear energy.展开更多
BACKGROUND The overlap of imaging manifestations among distinct splenic lesions gives rise to a diagnostic dilemma.Consequently,a definitive diagnosis primarily relies on his-tological results.The ultrasound(US)-guide...BACKGROUND The overlap of imaging manifestations among distinct splenic lesions gives rise to a diagnostic dilemma.Consequently,a definitive diagnosis primarily relies on his-tological results.The ultrasound(US)-guided coaxial core needle biopsy(CNB)not only procures sufficient tissue to help clarify the diagnosis,but reduces the incidence of puncture-related complications.CASE SUMMARY A 41-year-old female,with a history of pulmonary tuberculosis,was admitted to our hospital with multiple indeterminate splenic lesions.Gray-scale ultrasono-graphy demonstrated splenomegaly with numerous well-defined hypoechoic ma-sses.Abdominal contrast-enhanced computed tomography(CT)showed an en-larged spleen with multiple irregular-shaped,peripherally enhancing,hypodense lesions.Positron emission CT revealed numerous abnormal hyperglycemia foci.These imaging findings strongly indicated the possibility of infectious disease as the primary concern,with neoplastic lesions requiring exclusion.To obtain the precise pathological diagnosis,the US-guided coaxial CNB of the spleen was ca-rried out.The patient did not express any discomfort during the procedure.CONCLUSION Percutaneous US-guided coaxial CNB is an excellent and safe option for obtaining precise splenic tissue samples,as it significantly enhances sample yield for exact pathological analysis with minimum trauma to the spleen parenchyma and sur-rounding tissue.展开更多
BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP)is an accurate diagnostic method for choledocholithiasis and treatment option for stone removal.Additionally,ursodeoxycholic acid(UDCA)can dissolve choles...BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP)is an accurate diagnostic method for choledocholithiasis and treatment option for stone removal.Additionally,ursodeoxycholic acid(UDCA)can dissolve cholesterol stones and prevent their development and reappearance by lowering the cholesterol concen-tration in bile.Despite these treatment options,there are still patients who experience stone recurrence.The clinical data of 100 patients with choledochal stones who were hospitalized at the Yixing People’s Hospital and underwent ERCP for successful stone extraction between June 2020 and December 2022 were retrospectively collected.According to the post-ERCP treatment plan,100 patients were classified into UDCA(n=47)and control(n=53)groups.We aimed to assess the clinical efficacy and rate of relapse in the two patient populations.We then collected information(basic demographic data,clinical characteristics,and serum biochemical indicators)and determined the factors contributing to relapse using logistic regression analysis.Our secondary goal was to determine the effects of UDCA on liver function after ERCP.Compared to the control group,the UDCA group demonstrated a higher clinical effectiveness rate of 92.45%vs 78.72%(P<0.05).No significant differences were observed in liver function indices,including total bilirubin,direct bilirubin,gamma-glutamyl transpeptidase,alanine aminotransferase,alkaline phosphatase,and aspartate aminotransferase,between the two groups before treatment.After treatment,all liver function indices were significantly reduced.Comparing the control vs UDCA groups,the UDCA group exhibited significantly lower levels of all indices(55.39±6.53 vs 77.31±8.52,32.10±4.62 vs 45.39±5.69,142.32±14.21 vs 189.63±16.87,112.52±14.25 vs 149.36±15.36,122.61±16.00 vs 171.33±22.09,96.98±10.44 vs 121.35±11.57,respectively,all P<0.05).The stone recurrence rate was lower in the UDCA group(13.21%)in contrast with the control group(44.68%).Periampullary diverticula(OR:6.00,95%CI:1.69-21.30),maximum stone diameter(OR:1.69,95%CI:1.01-2.85),stone quantity>3(OR:4.23,95%CI:1.17-15.26),and positive bile culture(OR:7.61,95%CI:2.07-27.91)were independent factors that influenced the relapse of common bile duct stones after ERCP(P<0.05).Furthermore,postoperative UDCA was identified as a preventive factor(OR:0.07;95%CI:0.08-0.09).CONCLUSION The intervention effect of UDCA after ERCP for common bile duct stones is adequate,providing new research directions and references for the prevention and treatment of stone recurrence.展开更多
The deep cement mixing(DCM)is used to improve the capacity and reduce the settlement of the soft ground by forming cemented clay columns.The investigation on the mechanical behaviour of the DCM samples is limited to e...The deep cement mixing(DCM)is used to improve the capacity and reduce the settlement of the soft ground by forming cemented clay columns.The investigation on the mechanical behaviour of the DCM samples is limited to either laboratory-prepared samples or in-situ samples under unconfined compression.In this study,a series of drained and undrained triaxial shearing tests was performed on the in-situ cored DCM samples with high cement content to assess their mechanical behaviours.It is found that the drainage condition affects significantly the stiffness,peak and residual strengths of the DCM samples,which is mainly due to the state of excess pore water pressure at different strain levels,i.e.being positive before the peak deviatoric stress and negative after the peak deviatoric stress,in the undrained tests.The slope of the failure envelope changes obviously with the confining pressures,being steeper at lower stress levels and flatter at higher stress levels.The strength parameters,effective cohesion and friction angle obtained from lower stress levels(c′0 andφ′0)are 400 kPa and 58°,respectively,which are deemed to be true for design in most DCM applications where the in-situ stress levels are normally at lower values of 50-200 kPa.Additionally,the computed tomography(CT)scanning system was adopted to visualize the internal structures of DCM samples.It is found that the clay pockets existing inside the DCM samples due to uneven mixing affect markedly their stress-strain behaviour,which is one of the main reasons for the high variability of the DCM samples.展开更多
The core competencies of college students can influence their further learning,employment,and personal development.This paper explores college English teaching from the three aspects of core competencies:cultural foun...The core competencies of college students can influence their further learning,employment,and personal development.This paper explores college English teaching from the three aspects of core competencies:cultural foundation,self-development,and social participation.Adapting to the challenges posed by the new era for the cultivation of foreign language talents,the paper aims to improve students’cultural literacy,independent learning,the ability of problem discovery and problem solving,and critical cultural thinking,so as to make them more competitive in employment and entrepreneurship.展开更多
文摘While endoscopic retrograde cholangiopancreatography(ERCP)remains the primary treatment modality for common bile duct stones(CBDS)or choledocho-lithiasis due to advancements in instruments,surgical intervention,known as common bile duct exploration(CBDE),is still necessary in cases of difficult CBDS,failed endoscopic treatment,or altered anatomy.Recent evidence also supports CBDE in patients requesting single-step cholecystectomy and bile duct stone removal with comparable outcomes.This review elucidates relevant clinical anatomy,selection indications,and outcomes to enhance surgical understanding.The selection between trans-cystic(TC)vs trans-choledochal(TD)approaches is described,along with stone removal techniques and ductal closure.Detailed surgical techniques and strategies for both the TC and TD approaches,including instrument selection,is also provided.Additionally,this review comprehensively addresses operation-specific complications such as bile leakage,stricture,and entrapment,and focuses on preventive measures and treatment strategies.This review aims to optimize the management of CBDS through laparoscopic CBDE,with the goal of improving patient outcomes and minimizing risks.
基金supported in part by the National Natural Science Foundation of China under Grants 61975091,61905015,61575108,and 61505034by the Tsinghua Precision Medicine Foundation and“Bio-Brain+X”Advanced Imaging Instrument Development Seed Grant.
文摘In this paper,we present a distal-scanning common path probe for optical coherence tomography(OCT)equipped with a hollow ultrasonic motor and a simple and specially designed beam-splitter.This novel probe proves to be able to effectively circumvent polarization and dispersion mismatch caused by fiber motion and is more robust to a variety of interfering factors during the imaging process,experimentally compared to a conventional noncommon path probe.Furthermore,our design counteracts the attenuation of backscattering with depth and the fall-off of the signal,resulting in a more balanced signal range and greater imaging depth.Spectral-domain OCT imaging of phantom and biological tissue is also demonstrated with a sensitivity of∼100dB and a lateral resolution of∼3μm.This low-cost probe offers simplified system configuration and excellent robustness,and is therefore particularly suitable for clinical diagnosis as one-off medical apparatus.
文摘Introduction: In Cameroon, surgery remains the only approach in malignant obstructions of the common bile duct (MOCBD) even in palliative situations. The aim of this work was to describe the modalities of surgical treatment of MOCBD, evaluate the results and detect the factors associated with postoperative morbidity and mortality. Patients and Methods: We conducted an analytical observational study, with retrospective data collection from the files of patients operated upon for MOCBD. This was done in four referral hospitals in the city of Yaoundé for a 42-month period spanning from January 1, 2020 to June 30, 2023. Demographic data, clinical presentation, surgical data, and 30-day postoperative outcomes were collected. Results: We collected 71 files. The sex ratio was 1.4 and the mean age was 56 ± 11 years. Fifty-three (53) patients (74.6%) were overweight or obese and 10 patients (14.1%) were hypertensive. A clinical cholestasis syndrome was present in 69 patients (97.2%). Fifty-five (55) patients (77.5%) had a cancer of the head of the pancreas, 8 patients (11.3%) had an extra-hepatic cholangiocarcinoma and 8 patients (11.3%) had an ampullary adenocarcinoma. Eight (8) resections (11.3%) with curative intent had been carried out and in 63 cases (88.7%), surgery was palliative. Postoperative morbidity was 55.7%, influenced by advanced WHO stage (p = 0.02). Postoperative mortality was 25.7%, associated with a high ASA score (p = 0.01). Conclusion: Pancreatic head cancer is the main etiology of malignant obstructions of the common bile duct in Cameroon. Surgical treatment is most often palliative. Postoperative morbidity and mortality are high, influenced by high WHO and ASA scores.
基金supported by the National Science Foundation of China(Grant No.42230606)。
文摘Here,a nonhydrostatic alternative scheme(NAS)is proposed for the grey zone where the nonhydrostatic impact on the atmosphere is evident but not large enough to justify the necessity to include an implicit nonhydrostatic solver in an atmospheric dynamical core.The NAS is designed to replace this solver,which can be incorporated into any hydrostatic models so that existing well-developed hydrostatic models can effectively serve for a longer time.Recent advances in machine learning(ML)provide a potential tool for capturing the main complicated nonlinear-nonhydrostatic relationship.In this study,an ML approach called a neural network(NN)was adopted to select leading input features and develop the NAS.The NNs were trained and evaluated with 12-day simulation results of dry baroclinic-wave tests by the Weather Research and Forecasting(WRF)model.The forward time difference of the nonhydrostatic tendency was used as the target variable,and the five selected features were the nonhydrostatic tendency at the last time step,and four hydrostatic variables at the current step including geopotential height,pressure in two different forms,and potential temperature,respectively.Finally,a practical NAS was developed with these features and trained layer by layer at a 20-km horizontal resolution,which can accurately reproduce the temporal variation and vertical distribution of the nonhydrostatic tendency.Corrected by the NN-based NAS,the improved hydrostatic solver at different horizontal resolutions can run stably for at least one month and effectively reduce most of the nonhydrostatic errors in terms of system bias,anomaly root-mean-square error,and the error of the wave spatial pattern,which proves the feasibility and superiority of this scheme.
基金Project supported by the National Natural Science Foundation of China (Gant No.11872323)。
文摘Many networks exhibit the core/periphery structure.Core/periphery structure is a type of meso-scale structure that consists of densely connected core nodes and sparsely connected peripheral nodes.Core nodes tend to be well-connected,both among themselves and to peripheral nodes,which tend not to be well-connected to other nodes.In this brief report,we propose a new method to detect the core of a network by the centrality of each node.It is discovered that such nodes with non-negative centralities often consist in the core of the networks.The simulation is carried out on different real networks.The results are checked by the objective function.The checked results may show the effectiveness of the simulation results by the centralities of the nodes on the real networks.Furthermore,we discuss the characters of networks with the single core/periphery structure and point out the scope of the application of our method at the end of this paper.
基金Project supported by the National Natural Science Foundation of China(Grant No.11974253).
文摘Manganese-based perovskite is popular for research on ferromagnetic materials,and its spectroscopic studies are essential for understanding its electronic structure,dielectric,electrical,and magnetic properties.In this paper,the M-edge spectra of La ions and the M-edge,L-edge,and K-edge spectra of Mn ions in LaMnO3 are calculated by considering both the free-ion multiplet calculation and the crystal field effects.We analyze spectral shapes,identify peak origins,and estimate the oxidation states of La and Mn ions in LaMnO3 theoretically.It is concluded that La ions in LaMnO3 predominantly exist in the trivalent state,while Mn ions exist primarily in the trivalent state with a minor presence of tetravalent ions.Furthermore,the calculated spectra are in better conformity with the experimental spectra when the proportion of Mn3+is 90%and Mn4+is 10%.This article enhances our comprehension of the oxidation states of La and Mn within the crystal and also provides a valuable guidance for spectroscopic investigations of other manganates.
基金Supported by Social Science Funds for United Front Work Special Project of Fujian Provincial Department of Education(KJYT2204A).
文摘Under the historical background of promoting agricultural and rural modernization in an all-round way,this paper deeply analyzes the practical significance of digital construction in rural China,and explores the problems in the digitalization level of rural infrastructure,farmers digitalization awareness and accomplishment,and agricultural digital system.Countermeasures and suggestions are put forward from four aspects:digital village construction policy system,rural digital infrastructure construction,rural digital talent cultivation system,and agricultural digital system,and the rural digital construction of Huzhou City is taken as an example,in order to further realize the goal of empowering rural farmers with digital technology for common prosperity.
基金funding from the Ministry of Education,Culture,Research,and Technology,Indonesia,through the PDKN Research Grant with Contract No.041/E5/PG.02.00.PL/2023.
文摘Curcumin is a natural polyphenol that is used in various traditional medicines.However,its inherent properties,such as its rapid degradation and metabolism,low bioavailability,and short half-life,are serious problems that must be resolved.To this end,a drug carrier incorporating natural magnetic cores in a zeolite framework was developed and applied to the loading of curcumin in ethanol solutions.In this system,curcumin is encapsulated in a zeolite Na(ZNA)magnetic core–shell structure(Fe@Si/ZNA),which can be easily synthesized using an in situ method.Synthesis of Fe_(3)O_(4) nanoparticles was carried out from natural materials using a co-precipitation method.Analysis of the prepared magnetic core–shell structures and composites was carried out using vibrating-sample magnetometery,Fourier transform infrared spectroscopy,transmission electron microscopy,and x-ray diffraction.The cumulative loading of curcumin in the ZNA composite with 9%nanoparticles was found to reach 90.70%with a relatively long half-life of 32.49 min.Stability tests of curcumin loading in the composite showed that adding magnetic particles to the zeolite framework also increased the stability of the composite structure.Adsorption kinetics and isotherm studies also found that the system follows the pseudo-second-order and Langmuir isotherm models.
文摘The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around the rotation axis of the spinning Earth during the growth of the core the rotation should have been accelerated. Controversially the tidal dissipation by the Moon, which is mainly dependent on the availability of open shallow seas and the kind of Moon escape from a nearby position, acts towards a deceleration of the rotating Earth. Measurements of LOD for Phanerozoic and Precambrian times open ways to solve questions concerning the geodynamical history of the Earth. These measurements encompass investigations of growth patterns in fossils and depositional patterns in sediments (Cyclostratigraphy, Tidalites, Stromatolites, Rhythmites). These patterns contain information on the LOD and on the changing distance between Earth and Moon and can be used as well for a discussion about the growth of the Earth’s core. By updating an older paper with its simple approach as well as incorporating newly published results provided by the geoscientific community, a moderate to fast growth of the core in a hot early Earth will be favored controversially to the assumption of a delayed development of the core in an originally cold Earth. Core development with acceleration of Earth’s rotation and the contemporaneous slowing down due to tidal dissipation during the filling of the ocean may significantly interrelate.
基金supported by the Open Fund of Hubei Luojia Laboratory (No. 220100033)the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB41000000)+1 种基金National Natural Science Foundation of China (Grant Nos. 42174108, 41874094, 42192535 and 42242015)the Young Top-notch Talent Cultivation Program of Hubei Province。
文摘The Earth’s Free Core Nutation(FCN) causes Earth tides and forced nutation with frequencies close to the FCN that exhibit resonance effects.High-precision superconducting gravimeter(SG) and very long baseline interferometry(VLBI) provide good observation techniques for detecting the FCN parameters.However,some choices in data processing and solution procedures increase the uncertainty of the FCN parameters.In this study,we analyzed the differences and the effectiveness of weight function and ocean tide corrections in the FCN parameter detection using synthetic data,SG data from thirty-one stations,and the 10 celestial pole offset(CPO) series.The results show that significant discrepancies are caused by different computing options for a single SG station.The stacking method,which results in a variation of0.24-5 sidereal days(SDs) in the FCN period(T) and 10^(3)-10^(4) in the quality factor(Q) due to the selection of the weighting function and the ocean tide model(OTM),can effectively suppress this influence.The statistical analysis results of synthetic data shows that although different weight choices,while adjusting the proportion of diurnal tidal waves involved,do not significantly improve the accuracy of fitted FCN parameters from gravity observations.The study evaluated a series of OTMs using the loading correction efficiency.The fitting of FCN parameters can be improved by selecting the mean of appropriate OTMs based on the evaluation results.Through the estimation of the FCN parameters based on the forced nutation,it was found that the weight function P_(1) is more suitable than others,and different CPO series(after 2009) resulted in a difference of 0.4 SDs in the T and of 103 in the Q.We estimated the FCN parameters for SG(T=430.4±1.5 SDs and Q=1.52×10^(4)±2.5×10^(3)) and for VLBI(T=429.8±0.7 SDs,Q=1.88×10^(4)±2.1×10^(3)).
基金Supported by the People’s Livelihood Science and Technology Innovation Project of the Bureau of Science and Technology of Jiaxing City,No.2021AD30091.
文摘BACKGROUND Undifferentiated pleomorphic sarcoma(UPS)is a rare malignant mesenchymal tumor with a poor prognosis.It mainly occurs in the extremities,trunk,head and neck,and retroperitoneum regions.Owing to the lack of specific clinical manifestations and imaging features,UPS diagnosis mainly depends on pathological and immunohistochemical examinations for exclusive diagnosis.Here we report an extremely rare case of high-grade UPS in the common bile duct(CBD).There are limited available data on such cases.CASE SUMMARY A 70-year-old woman was admitted to our department with yellow eyes and urine accompanied by upper abdominal distending pain for 2 wk.Her laboratory data suggested significantly elevated hepatorenal function levels.The imaging data revealed calculous cholecystitis,intrahepatic and extrahepatic bile duct dilation with extrahepatic bile duct calculi,and a space-occupying lesion at the distal CBD.After endoscopic biliary stenting and symptomatic support therapy,CBD exploration and biopsy were performed.The frozen section indicated malignant spindle cell tumor of the CBD mass,and further radical pancreaticoduodenectomy was performed.Finally,the neoplasm was diagnosed as a high-grade UPS combined with the light-microscopic morphology and immunohistochemical results.CONCLUSION This extremely rare case highlighted the need for increasing physicians'vigilance,reducing the odds of misdiagnosis,and providing appropriate treatment strategies.
文摘Large Language Models (LLMs) have revolutionized Generative Artificial Intelligence (GenAI) tasks, becoming an integral part of various applications in society, including text generation, translation, summarization, and more. However, their widespread usage emphasizes the critical need to enhance their security posture to ensure the integrity and reliability of their outputs and minimize harmful effects. Prompt injections and training data poisoning attacks are two of the most prominent vulnerabilities in LLMs, which could potentially lead to unpredictable and undesirable behaviors, such as biased outputs, misinformation propagation, and even malicious content generation. The Common Vulnerability Scoring System (CVSS) framework provides a standardized approach to capturing the principal characteristics of vulnerabilities, facilitating a deeper understanding of their severity within the security and AI communities. By extending the current CVSS framework, we generate scores for these vulnerabilities such that organizations can prioritize mitigation efforts, allocate resources effectively, and implement targeted security measures to defend against potential risks.
文摘This study aims to thoroughly investigate the axial power peaking factors (PPF) within the low-enriched uranium (LEU) core of the Ghana Research Reactor-1 (GHARR-1). This study uses advanced simulation tools, like the MCNPX code for analysing neutron behavior and the PARET/ANL code for understanding power variations, to get a clearer picture of the reactor’s performance. The analysis covers the initial six years of GHARR-1’s operation and includes projections for its whole 60-year lifespan. We closely observed the patterns of both the highest and average PPFs at 21 axial nodes, with measurements taken every ten years. The findings of this study reveal important patterns in power distribution within the core, which are essential for improving the safety regulations and fuel management techniques of the reactor. We provide a meticulous approach, extensive data, and an analysis of the findings, highlighting the significance of continuous monitoring and analysis for proactive management of nuclear reactors. The findings of this study not only enhance our comprehension of nuclear reactor safety but also carry significant ramifications for sustainable energy progress in Ghana and the wider global context. Nuclear engineering is essential in tackling global concerns, such as the demand for clean and dependable energy sources. Research on optimising nuclear reactors, particularly in terms of safety and efficiency, is crucial for the ongoing advancement and acceptance of nuclear energy.
文摘BACKGROUND The overlap of imaging manifestations among distinct splenic lesions gives rise to a diagnostic dilemma.Consequently,a definitive diagnosis primarily relies on his-tological results.The ultrasound(US)-guided coaxial core needle biopsy(CNB)not only procures sufficient tissue to help clarify the diagnosis,but reduces the incidence of puncture-related complications.CASE SUMMARY A 41-year-old female,with a history of pulmonary tuberculosis,was admitted to our hospital with multiple indeterminate splenic lesions.Gray-scale ultrasono-graphy demonstrated splenomegaly with numerous well-defined hypoechoic ma-sses.Abdominal contrast-enhanced computed tomography(CT)showed an en-larged spleen with multiple irregular-shaped,peripherally enhancing,hypodense lesions.Positron emission CT revealed numerous abnormal hyperglycemia foci.These imaging findings strongly indicated the possibility of infectious disease as the primary concern,with neoplastic lesions requiring exclusion.To obtain the precise pathological diagnosis,the US-guided coaxial CNB of the spleen was ca-rried out.The patient did not express any discomfort during the procedure.CONCLUSION Percutaneous US-guided coaxial CNB is an excellent and safe option for obtaining precise splenic tissue samples,as it significantly enhances sample yield for exact pathological analysis with minimum trauma to the spleen parenchyma and sur-rounding tissue.
文摘BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP)is an accurate diagnostic method for choledocholithiasis and treatment option for stone removal.Additionally,ursodeoxycholic acid(UDCA)can dissolve cholesterol stones and prevent their development and reappearance by lowering the cholesterol concen-tration in bile.Despite these treatment options,there are still patients who experience stone recurrence.The clinical data of 100 patients with choledochal stones who were hospitalized at the Yixing People’s Hospital and underwent ERCP for successful stone extraction between June 2020 and December 2022 were retrospectively collected.According to the post-ERCP treatment plan,100 patients were classified into UDCA(n=47)and control(n=53)groups.We aimed to assess the clinical efficacy and rate of relapse in the two patient populations.We then collected information(basic demographic data,clinical characteristics,and serum biochemical indicators)and determined the factors contributing to relapse using logistic regression analysis.Our secondary goal was to determine the effects of UDCA on liver function after ERCP.Compared to the control group,the UDCA group demonstrated a higher clinical effectiveness rate of 92.45%vs 78.72%(P<0.05).No significant differences were observed in liver function indices,including total bilirubin,direct bilirubin,gamma-glutamyl transpeptidase,alanine aminotransferase,alkaline phosphatase,and aspartate aminotransferase,between the two groups before treatment.After treatment,all liver function indices were significantly reduced.Comparing the control vs UDCA groups,the UDCA group exhibited significantly lower levels of all indices(55.39±6.53 vs 77.31±8.52,32.10±4.62 vs 45.39±5.69,142.32±14.21 vs 189.63±16.87,112.52±14.25 vs 149.36±15.36,122.61±16.00 vs 171.33±22.09,96.98±10.44 vs 121.35±11.57,respectively,all P<0.05).The stone recurrence rate was lower in the UDCA group(13.21%)in contrast with the control group(44.68%).Periampullary diverticula(OR:6.00,95%CI:1.69-21.30),maximum stone diameter(OR:1.69,95%CI:1.01-2.85),stone quantity>3(OR:4.23,95%CI:1.17-15.26),and positive bile culture(OR:7.61,95%CI:2.07-27.91)were independent factors that influenced the relapse of common bile duct stones after ERCP(P<0.05).Furthermore,postoperative UDCA was identified as a preventive factor(OR:0.07;95%CI:0.08-0.09).CONCLUSION The intervention effect of UDCA after ERCP for common bile duct stones is adequate,providing new research directions and references for the prevention and treatment of stone recurrence.
基金funded by the Environment and Conservation Fund(Grant Nos.2020-170 and 2021-156)the National Natural Science Foundation of China(Grant No.42102327).
文摘The deep cement mixing(DCM)is used to improve the capacity and reduce the settlement of the soft ground by forming cemented clay columns.The investigation on the mechanical behaviour of the DCM samples is limited to either laboratory-prepared samples or in-situ samples under unconfined compression.In this study,a series of drained and undrained triaxial shearing tests was performed on the in-situ cored DCM samples with high cement content to assess their mechanical behaviours.It is found that the drainage condition affects significantly the stiffness,peak and residual strengths of the DCM samples,which is mainly due to the state of excess pore water pressure at different strain levels,i.e.being positive before the peak deviatoric stress and negative after the peak deviatoric stress,in the undrained tests.The slope of the failure envelope changes obviously with the confining pressures,being steeper at lower stress levels and flatter at higher stress levels.The strength parameters,effective cohesion and friction angle obtained from lower stress levels(c′0 andφ′0)are 400 kPa and 58°,respectively,which are deemed to be true for design in most DCM applications where the in-situ stress levels are normally at lower values of 50-200 kPa.Additionally,the computed tomography(CT)scanning system was adopted to visualize the internal structures of DCM samples.It is found that the clay pockets existing inside the DCM samples due to uneven mixing affect markedly their stress-strain behaviour,which is one of the main reasons for the high variability of the DCM samples.
基金supported by Educational Science Research Project of Beijing Union University“A Study on the Cultivation Path of Core Competencies of English Talents in Universities Under the Background of New Liberal Arts”(JK202209).
文摘The core competencies of college students can influence their further learning,employment,and personal development.This paper explores college English teaching from the three aspects of core competencies:cultural foundation,self-development,and social participation.Adapting to the challenges posed by the new era for the cultivation of foreign language talents,the paper aims to improve students’cultural literacy,independent learning,the ability of problem discovery and problem solving,and critical cultural thinking,so as to make them more competitive in employment and entrepreneurship.