High geostress,a typical attribute of tunnels located at significant depths,is crucial in causing stress-induced failure and influencing the stability of the tunnel crown.This study developed an analytical method for ...High geostress,a typical attribute of tunnels located at significant depths,is crucial in causing stress-induced failure and influencing the stability of the tunnel crown.This study developed an analytical method for the failure mechanism that occurs in deep-buried tunnel roofs,taking into account the influence of geostress.The limit analysis theory was utilized for deriving analytical solutions about the geometry of the collapsing surface and the limit supporting pressure.The collapsing surface obtained by the analytical solution was validated by the findings of the physical model test,which shows a high level of agreement with the actual one.An extensive investigation was done to explore the effects of the lateral pressure coefficients,the tunnel buried depth,the geological conditions of the surrounding rock,the long-short axis ratio,and the size of the tunnel profile.The findings indicate that an increase in the lateral pressure coefficient from 0.5 to 1.5 results in a reduction in the height of the collapsing zone by 2.08 m and the width of the collapsing zone by 1.15 m,while simultaneously increases the limit supporting pressure by 18.9%.The proposed upper bound method accurately determines the limit supporting pressure and the geometry of the collapsing surface,which aligns well with the results acquired through numerical modelling and on-site monitoring in actual engineering applications.The proposed analytical method can serve as a reference for similar crown failure issues of deep-buried tunnels.展开更多
Dissolution mechanism and favorable reservoir distribution prediction are the key problems restricting oil and gas exploration in deep-buried layers.In this paper,the Enping Formation and Zhuhai Formation in Baiyun Sa...Dissolution mechanism and favorable reservoir distribution prediction are the key problems restricting oil and gas exploration in deep-buried layers.In this paper,the Enping Formation and Zhuhai Formation in Baiyun Sag of South China Sea was taken as a target.Based on the thin section,scanning electron microscopy,X-ray diffraction,porosity/permeability measurement,and mercury injection,influencing factors of dissolution were examined,and a dissolution model was established.Further,high-quality reservoirs were predicted temporally and spatially.The results show that dissolved pores constituted the main space of the Paleogene sandstone reservoir.Dissolution primarily occurred in the coarse-and medium-grained sandstones in the subaerial and subaqueous distributary channels,while dissolution was limited in fine-grained sandstones and inequigranular sandstones.The main dissolved minerals were feldspar,tuffaceous matrix,and diagenetic cement.Kaolinization of feldspar and illitization of kaolinite are the main dissolution pathways,but they occur at various depths and temperatures with different geothermal gradients.Dissolution is controlled by four factors,in terms of depositional facies,source rock evolution,overpressure,and fault activities,which co-acted at the period of 23.8–13.8 Ma,and resulted into strong dissolution.Additionally,based on these factors,high-quality reservoirs of the Enping and Zhuhai formations are predicted in the northern slope,southwestern step zone,and Liuhua uplift in the Baiyun Sag.展开更多
Introduction: Fibroscan is a recent, non-invasive and non-irradiating diagnostic method. It is based on the principle of ultrasound, which enables liver tissue elasticity to be quantified using a probe, and fibrosis t...Introduction: Fibroscan is a recent, non-invasive and non-irradiating diagnostic method. It is based on the principle of ultrasound, which enables liver tissue elasticity to be quantified using a probe, and fibrosis to be assessed. Fibroscan measures both elasticity correlated with hepatic fibrosis and CAP correlated with steatosis. The aim of this study was to evaluate hepatic fibrosis and steatosis using pulse elastometry (Fibroscan/CAP). Methods: This was a descriptive and analytical cross-sectional study in which 170 patients were included. It was conducted from October 1 2021 to December 31 2023, i.e. 27 months, in an outpatient clinic in the hepato-gastroenterology department of the Donka national hospital of the CHU Conakry. Results: Of the 170 patients identified, 87 were male (51%) and 83 female (49%), giving a M/F sex ratio of 1.04. The average age of our patients was 40. The 30 - 50 age group was the most affected, with a frequency of 58.23% (n = 99), followed by the 50 age group with a frequency of 29.41% (n = 50). Hepatomegaly, steatotic liver on ultrasonography, transaminase elevation and obesity were the main indications, respectively: (21.76%), (17.65%), (14.71%), and (13.53%). The examinations were requested by hepatogastroenterologists (47.06%), diabetologists (35.88%) and general practitioners (29%). Of the 170 patients, 100 patients (58.82%) had no significant fibrosis F0F1, 39 (22.94%) had moderate fibrosis F2, 20 patients (11.76%) had severe fibrosis F3 and 11 patients (6.47%) had fibrosis F4. Hepatic steatosis: 62 patients (36.47%) had no S0 steatosis;29.41% had S1 steatosis, 20% had S2 steatosis and 24 patients (14.11%) had S3 steatosis. Abdominal ultrasound revealed a normal liver in 67.05% of patients, hepatic steatosis in 29.41% and non-decompensated cirrhosis in 6 cases. Thus, 108 patients had the parameters required to calculate the Fatty Liver Index (FLI), steatosis was present in 20% of our patients, while 29.41% had an undetermined status and 24 14.11% had a normal FLI. Conclusion: Identifying subjects at risk of metabolic steatopathy, diagnosing and managing these patients is a public health issue and one of the future challenges of hepato-gastroenterology. Fibroscan is an increasingly popular screening tool for hepatic fibrosis and steatosis. The fight against obesity must be a priority.展开更多
The Cap Pushing Response (CPR) is a free-flying technique used to study learning and memory in honey bees (Apis mellifera). The series of experiments outlined in this paper aimed to test whether honey bees exhibit the...The Cap Pushing Response (CPR) is a free-flying technique used to study learning and memory in honey bees (Apis mellifera). The series of experiments outlined in this paper aimed to test whether honey bees exhibit the cognitive concept of “expectancy” utilizing the CPR in a weight differentiation paradigm. Five previous experiments in our laboratory have explored whether the concept of expectancy can account for honey bee performance and have all failed to support the cognitive interpretation. The first experiment examined if bees could differentiate between the two caps in the amount of force they used to push the cap and the distance the cap was pushed when the caps were presented one at a time. The second experiment explored cap weight preference by presenting bees with a choice between the two caps. The third and fourth experiments tested the bee’s ability to expect reward or punishment based on cap weight. Results revealed that bees were found to have a strong preference for the light cap and therefore were not able to expect reward or punishment based on cap weight. These experiments contribute to the debate on whether bees have “cognitive” representations and continue to support the behaviorist interpretation.展开更多
Rock fall accidents in mountainous cliff areas have significant consequences for human life and transportation.This study aimed to evaluate the rockfall hazard in the Cap Aokas cliff region located along the northeast...Rock fall accidents in mountainous cliff areas have significant consequences for human life and transportation.This study aimed to evaluate the rockfall hazard in the Cap Aokas cliff region located along the northeast coast of Algeria by identifying the key factors contributing to rockfall occurrence.We employed a combination of kinematic analysis,Matterocking method,and 3D trajectory simulations to determine zones that are susceptible to rockfall mobilization.By using a probabilistic and structural approach in conjunction with photogrammetry,we identified the controlling factors.The kinematic analysis revealed the presence of five discontinuity families,which indicated both plane and wedge failure modes.The 3D trajectory simulations demonstrated that the falling blocks followed the stream direction.We then validated the susceptibility maps generated from the analysis using aerial photos and historical rockfall events.The findings of this study enhance our understanding of rockfall phenomena and provide valuable insights for the development of effective strategies to mitigate rockfall hazards.展开更多
BACKGROUND The stent embedded in the esophageal mucosa is one of the complications after stenting for esophageal stricture.We present a case of stent adjustment with the aid of a transparent cap after endoscopic injec...BACKGROUND The stent embedded in the esophageal mucosa is one of the complications after stenting for esophageal stricture.We present a case of stent adjustment with the aid of a transparent cap after endoscopic injection of an esophageal varices stent.CASE SUMMARY A 61-year-old male patient came to the hospital with discomfort of the chest after the stent implanted for the stenosis because of endoscopic injection of esophageal varices.The gastroscopy was performed,and the stent embedded into the esophageal mucosa.At first,we pulled the recycling line for shrinking the stent,however,the mucosa could not be removed from the stent.Then a forceps was performed to remove the mucosa in the stent,nevertheless,the bleeding form the mucosa was obvious.And then,we used a transparent cap to scrape the mucosa along the stent,and the mucosa were removed successfully without bleeding.CONCLUSION A transparent cap helps gastroscopy to remove the mucosa embedded in the stent after endoscopic injection of the esophageal varices stent.展开更多
基金supported partially by the National Natural Science Foundation of China(42277158,41972277,and U1934212)。
文摘High geostress,a typical attribute of tunnels located at significant depths,is crucial in causing stress-induced failure and influencing the stability of the tunnel crown.This study developed an analytical method for the failure mechanism that occurs in deep-buried tunnel roofs,taking into account the influence of geostress.The limit analysis theory was utilized for deriving analytical solutions about the geometry of the collapsing surface and the limit supporting pressure.The collapsing surface obtained by the analytical solution was validated by the findings of the physical model test,which shows a high level of agreement with the actual one.An extensive investigation was done to explore the effects of the lateral pressure coefficients,the tunnel buried depth,the geological conditions of the surrounding rock,the long-short axis ratio,and the size of the tunnel profile.The findings indicate that an increase in the lateral pressure coefficient from 0.5 to 1.5 results in a reduction in the height of the collapsing zone by 2.08 m and the width of the collapsing zone by 1.15 m,while simultaneously increases the limit supporting pressure by 18.9%.The proposed upper bound method accurately determines the limit supporting pressure and the geometry of the collapsing surface,which aligns well with the results acquired through numerical modelling and on-site monitoring in actual engineering applications.The proposed analytical method can serve as a reference for similar crown failure issues of deep-buried tunnels.
基金The National Natural Science Foundation of China under contract No.42202157the China National Offshore Oil Corporation Co.,Ltd.Major Production and Scientific Research Program under contract No.2019KT-SC-22。
文摘Dissolution mechanism and favorable reservoir distribution prediction are the key problems restricting oil and gas exploration in deep-buried layers.In this paper,the Enping Formation and Zhuhai Formation in Baiyun Sag of South China Sea was taken as a target.Based on the thin section,scanning electron microscopy,X-ray diffraction,porosity/permeability measurement,and mercury injection,influencing factors of dissolution were examined,and a dissolution model was established.Further,high-quality reservoirs were predicted temporally and spatially.The results show that dissolved pores constituted the main space of the Paleogene sandstone reservoir.Dissolution primarily occurred in the coarse-and medium-grained sandstones in the subaerial and subaqueous distributary channels,while dissolution was limited in fine-grained sandstones and inequigranular sandstones.The main dissolved minerals were feldspar,tuffaceous matrix,and diagenetic cement.Kaolinization of feldspar and illitization of kaolinite are the main dissolution pathways,but they occur at various depths and temperatures with different geothermal gradients.Dissolution is controlled by four factors,in terms of depositional facies,source rock evolution,overpressure,and fault activities,which co-acted at the period of 23.8–13.8 Ma,and resulted into strong dissolution.Additionally,based on these factors,high-quality reservoirs of the Enping and Zhuhai formations are predicted in the northern slope,southwestern step zone,and Liuhua uplift in the Baiyun Sag.
文摘Introduction: Fibroscan is a recent, non-invasive and non-irradiating diagnostic method. It is based on the principle of ultrasound, which enables liver tissue elasticity to be quantified using a probe, and fibrosis to be assessed. Fibroscan measures both elasticity correlated with hepatic fibrosis and CAP correlated with steatosis. The aim of this study was to evaluate hepatic fibrosis and steatosis using pulse elastometry (Fibroscan/CAP). Methods: This was a descriptive and analytical cross-sectional study in which 170 patients were included. It was conducted from October 1 2021 to December 31 2023, i.e. 27 months, in an outpatient clinic in the hepato-gastroenterology department of the Donka national hospital of the CHU Conakry. Results: Of the 170 patients identified, 87 were male (51%) and 83 female (49%), giving a M/F sex ratio of 1.04. The average age of our patients was 40. The 30 - 50 age group was the most affected, with a frequency of 58.23% (n = 99), followed by the 50 age group with a frequency of 29.41% (n = 50). Hepatomegaly, steatotic liver on ultrasonography, transaminase elevation and obesity were the main indications, respectively: (21.76%), (17.65%), (14.71%), and (13.53%). The examinations were requested by hepatogastroenterologists (47.06%), diabetologists (35.88%) and general practitioners (29%). Of the 170 patients, 100 patients (58.82%) had no significant fibrosis F0F1, 39 (22.94%) had moderate fibrosis F2, 20 patients (11.76%) had severe fibrosis F3 and 11 patients (6.47%) had fibrosis F4. Hepatic steatosis: 62 patients (36.47%) had no S0 steatosis;29.41% had S1 steatosis, 20% had S2 steatosis and 24 patients (14.11%) had S3 steatosis. Abdominal ultrasound revealed a normal liver in 67.05% of patients, hepatic steatosis in 29.41% and non-decompensated cirrhosis in 6 cases. Thus, 108 patients had the parameters required to calculate the Fatty Liver Index (FLI), steatosis was present in 20% of our patients, while 29.41% had an undetermined status and 24 14.11% had a normal FLI. Conclusion: Identifying subjects at risk of metabolic steatopathy, diagnosing and managing these patients is a public health issue and one of the future challenges of hepato-gastroenterology. Fibroscan is an increasingly popular screening tool for hepatic fibrosis and steatosis. The fight against obesity must be a priority.
文摘The Cap Pushing Response (CPR) is a free-flying technique used to study learning and memory in honey bees (Apis mellifera). The series of experiments outlined in this paper aimed to test whether honey bees exhibit the cognitive concept of “expectancy” utilizing the CPR in a weight differentiation paradigm. Five previous experiments in our laboratory have explored whether the concept of expectancy can account for honey bee performance and have all failed to support the cognitive interpretation. The first experiment examined if bees could differentiate between the two caps in the amount of force they used to push the cap and the distance the cap was pushed when the caps were presented one at a time. The second experiment explored cap weight preference by presenting bees with a choice between the two caps. The third and fourth experiments tested the bee’s ability to expect reward or punishment based on cap weight. Results revealed that bees were found to have a strong preference for the light cap and therefore were not able to expect reward or punishment based on cap weight. These experiments contribute to the debate on whether bees have “cognitive” representations and continue to support the behaviorist interpretation.
基金the support provided by the Laboratory of Applied Research in Engineering Geology, Geotechnics, Water Sciences, and Environment, Setif 1 University, Algeria
文摘Rock fall accidents in mountainous cliff areas have significant consequences for human life and transportation.This study aimed to evaluate the rockfall hazard in the Cap Aokas cliff region located along the northeast coast of Algeria by identifying the key factors contributing to rockfall occurrence.We employed a combination of kinematic analysis,Matterocking method,and 3D trajectory simulations to determine zones that are susceptible to rockfall mobilization.By using a probabilistic and structural approach in conjunction with photogrammetry,we identified the controlling factors.The kinematic analysis revealed the presence of five discontinuity families,which indicated both plane and wedge failure modes.The 3D trajectory simulations demonstrated that the falling blocks followed the stream direction.We then validated the susceptibility maps generated from the analysis using aerial photos and historical rockfall events.The findings of this study enhance our understanding of rockfall phenomena and provide valuable insights for the development of effective strategies to mitigate rockfall hazards.
基金Supported by Hangzhou Agricultural and Social Development Research Guidance Project,No.20220919Y037.
文摘BACKGROUND The stent embedded in the esophageal mucosa is one of the complications after stenting for esophageal stricture.We present a case of stent adjustment with the aid of a transparent cap after endoscopic injection of an esophageal varices stent.CASE SUMMARY A 61-year-old male patient came to the hospital with discomfort of the chest after the stent implanted for the stenosis because of endoscopic injection of esophageal varices.The gastroscopy was performed,and the stent embedded into the esophageal mucosa.At first,we pulled the recycling line for shrinking the stent,however,the mucosa could not be removed from the stent.Then a forceps was performed to remove the mucosa in the stent,nevertheless,the bleeding form the mucosa was obvious.And then,we used a transparent cap to scrape the mucosa along the stent,and the mucosa were removed successfully without bleeding.CONCLUSION A transparent cap helps gastroscopy to remove the mucosa embedded in the stent after endoscopic injection of the esophageal varices stent.