Accurate prediction of formation pore pressure is essential to predict fluid flow and manage hydrocarbon production in petroleum engineering.Recent deep learning technique has been receiving more interest due to the g...Accurate prediction of formation pore pressure is essential to predict fluid flow and manage hydrocarbon production in petroleum engineering.Recent deep learning technique has been receiving more interest due to the great potential to deal with pore pressure prediction.However,most of the traditional deep learning models are less efficient to address generalization problems.To fill this technical gap,in this work,we developed a new adaptive physics-informed deep learning model with high generalization capability to predict pore pressure values directly from seismic data.Specifically,the new model,named CGP-NN,consists of a novel parametric features extraction approach(1DCPP),a stacked multilayer gated recurrent model(multilayer GRU),and an adaptive physics-informed loss function.Through machine training,the developed model can automatically select the optimal physical model to constrain the results for each pore pressure prediction.The CGP-NN model has the best generalization when the physicsrelated metricλ=0.5.A hybrid approach combining Eaton and Bowers methods is also proposed to build machine-learnable labels for solving the problem of few labels.To validate the developed model and methodology,a case study on a complex reservoir in Tarim Basin was further performed to demonstrate the high accuracy on the pore pressure prediction of new wells along with the strong generalization ability.The adaptive physics-informed deep learning approach presented here has potential application in the prediction of pore pressures coupled with multiple genesis mechanisms using seismic data.展开更多
A method for in-situ stress measurement via fiber optics was proposed. The method utilizes the relationship between rock mass elastic parameters and in-situ stress. The approach offers the advantage of long-term stres...A method for in-situ stress measurement via fiber optics was proposed. The method utilizes the relationship between rock mass elastic parameters and in-situ stress. The approach offers the advantage of long-term stress measurements with high spatial resolution and frequency, significantly enhancing the ability to measure in-situ stress. The sensing casing, spirally wrapped with fiber optic, is cemented into the formation to establish a formation sensing nerve. Injecting fluid into the casing generates strain disturbance, establishing the relationship between rock mass properties and treatment pressure.Moreover, an optimization algorithm is established to invert the elastic parameters of formation via fiber optic strains. In the first part of this paper series, we established the theoretical basis for the inverse differential strain analysis method for in-situ stress measurement, which was subsequently verified using an analytical model. This paper is the fundamental basis for the inverse differential strain analysis method.展开更多
The efficient development and exploitation of shale oil depends on long-distance horizontal wells. As the degreeof cleaning of the wellbore plays a key role in these processes, in this study, this problem is investiga...The efficient development and exploitation of shale oil depends on long-distance horizontal wells. As the degreeof cleaning of the wellbore plays a key role in these processes, in this study, this problem is investigated experimentallyby focusing on the dimensionless cuttings bed height. A method is proposed to calculate the horizontalwellhydraulic extension taking into account the influence of the wellbore cleaning degree on the wellborepressure distribution and assess the effect of a variety of factors such as the bottom hole pressure, the circulatingpressure drop, the drilling pump performance and the formation properties. The analysis shows that the hydraulicextension of horizontal wells decreases with an increase in the cuttings bed height, and the higher the displacementof drilling fluid, the faster the hydraulic extension declines. The annular pressure drop of the horizontalsection increases with the increase of the cuttings bed height, resulting in a higher bottom-hole pressure. Severalarguments are provided to guide the safe drilling of shale oil horizontal wells and overcome the limits of currenttechnological approaches.展开更多
Shale reservoirs contain numerous bedding fractures,making the formation of complex fracture networks during fracturing a persistent technical challenge in evaluating shale fracture morphology.Distributed optical fibe...Shale reservoirs contain numerous bedding fractures,making the formation of complex fracture networks during fracturing a persistent technical challenge in evaluating shale fracture morphology.Distributed optical fiber sensing technology can effectively capture the process of fracture initiation and propagation,yet the evaluation method for the initiation and propagation of bedding fractures remains immature.This study integrates a distributed optical fiber sensing device based on optical frequency domain reflectometry(OFDR)with a large-scale true tri-axial fracturing physical simulation apparatus to conduct real-time monitoring experiments on shale samples from the Lianggaoshan Formation in the Sichuan Basin,where bedding is well-developed.The experimental results demonstrate that two bedding fractures in the shale sample initiated and propagated.The evolution characteristics of fiber-optic strain in a horizontal adjacent well,induced by the initiation and propagation of bedding fractures,are characterized by the appearance of a tensile strain convergence zone in the middle of the optical fiber,flanked by two compressive strain convergence zones.The initiation and propagation of the distal bedding fracture causes the fiber-optic strain in the horizontal adjacent well to superimpose,with the asymmetric propagation of the bedding fracture leading to an asymmetric tensile strain convergence zone in the optical fiber.Utilizing a finite element method coupled with a cohesive element approach,a forward model of fiber-optic strain in the horizontal adjacent well induced by the initiation and propagation of hydraulic fracturing bedding fractures was constructed.Numerical simulation analyses were conducted to evaluate the evolution of fiber-optic strain in the horizontal adjacent well,confirming the correctness of the observed evolution characteristics.The presence of a"wedge-shaped"tensile strain convergence zone in the fiber-optic strain waterfall plot,accompanied by two compressive strain convergence zones,indicates the initiation and propagation of bedding fractures during the fracturing process.These findings provide valuable insights for interpreting distributed fiber-optic data in shale fracturing field applications.展开更多
Exploiting the hierarchical dependence behind user behaviour is critical for click-through rate (CRT) prediction in recommender systems. Existing methods apply attention mechanisms to obtain the weights of items;howev...Exploiting the hierarchical dependence behind user behaviour is critical for click-through rate (CRT) prediction in recommender systems. Existing methods apply attention mechanisms to obtain the weights of items;however, the authors argue that deterministic attention mechanisms cannot capture the hierarchical dependence between user behaviours because they treat each user behaviour as an independent individual and cannot accurately express users' flexible and changeable interests. To tackle this issue, the authors introduce the Bayesian attention to the CTR prediction model, which treats attention weights as data-dependent local random variables and learns their distribution by approximating their posterior distribution. Specifically, the prior knowledge is constructed into the attention weight distribution, and then the posterior inference is utilised to capture the implicit and flexible user intentions. Extensive experiments on public datasets demonstrate that our algorithm outperforms state-of-the-art algorithms. Empirical evidence shows that random attention weights can predict user intentions better than deterministic ones.展开更多
Whether hydraulic fractures could connect multiple gas zones in the vertical plane is the key to fracturing treatment to jointly exploit coalbed methane and tight sandstone gas through integrative hydraulic fracturing...Whether hydraulic fractures could connect multiple gas zones in the vertical plane is the key to fracturing treatment to jointly exploit coalbed methane and tight sandstone gas through integrative hydraulic fracturing in tight sandstone–coal interbedded formations. Laboratory true triaxial hydraulic fracturing experiments were conducted on layered specimens with di erent combination types of natural sandstone and coal to simulate the propagation behavior of hydraulic fractures. The effects of the fracture initiation position, fracturing fluid viscosity and injection rate were discussed. The results showed that di erent fracture morphologies could be found. When initiating from coal seams, three patterns of fracture initiation and propagation were obtained:(1) The main hydraulic fracture initiated and propagated along the natural fractures and then diverged due to the effects of in situ stress and formed secondary fractures.(2) The hydraulic fracture initiated and propagated in the direction of the maximum horizontal stress.(3) Multiple fractures initiated and propagated at the same time. With the same fracturing fluid viscosity and injection rate, the hydraulic fractures initiating in sandstones had greater chances than those in coal seams to penetrate interfaces and enter neighboring layers. Excessively small or large fracturing fluid viscosity and injection rate would do harm to the vertical extension height of the induced fracture and improvement of the stimulated reservoir volume. Compared with operation parameters(fracturing fluid viscosity and injection rate), the natural weak planes in coals were considered to be the key factor that a ected the fracture propagation path. The experimental results would make some contributions to the development of tight sandstone–coal interbedded reservoirs.展开更多
Objective:To observe dynamic changes of levels of monocyte chemotactic protein-1(MCP-1),tumor necrosis factor-α(TNF-α) and interleukin-8(IL-8) in patients with acute pancreatitis and to investigate its evaluation va...Objective:To observe dynamic changes of levels of monocyte chemotactic protein-1(MCP-1),tumor necrosis factor-α(TNF-α) and interleukin-8(IL-8) in patients with acute pancreatitis and to investigate its evaluation value on the severity of acute pancreatitis.Methods:A total of 109 patients with acute pancreatitis admitted were divided into mild acute pancreatitis group(MAP group,42 cases),moderately severe acute pancreatitis(MSAP group,35 cases)and severe acute pancreatitis(SAP group,32 cases).ELISA was used to detect the serum levels of MCP-1,TNF-α and IL-8 of patients at day 1,day 4 and day 7 of admission to hospital.Results:The serum levels of MCP-1,TNF-α and IL-8 from MAP group,MSAP group and SAP group at day 1 of admission to hospital all significantly increased.There was a significant difference between MAP group and control group,MSAP group and MAP group,SAP group and MSAP group(P<0.05).The serum concentrations of IL-8 from MASP group and SAP group obviously increased at day 1,and there was significant difference between MASP group and MAP group,SAP group and MSAP group(P<0.05),while the difference between MAP group and control group was not obvious(P>0.05);The serum concentrations of MCP-1,TNF-α and IL-8 from MAP group all reached the highest level at day 4,which were significantly higher than the detection levels at day 1.In MSAP group and SAP group,the serum concentrations of MCP-1,TNF-α and IL-8 were the highest at day 1,which were significantly higher than the detection levels at day 4 and 7.At each detecting timing,the serum concentrations of MCP-1,TNF-α and IL-8 from MSAP group and SAP group were all higher than those of MAP group and MSAP group,respectively.Conclusions:The dynamic changes of serum levels of MCP-1,TNF-α and IL-8 in patients with acute pancreatitis have their rules,and the change rule of MAP group was different with that of MSAP and SAP group,which showed the reference value for the diagnosis and illness severity evaluation of acute pancreatitis.展开更多
Hydraulic fracture is important in unconventional oil and gas exploration.During the propagation of the hydraulic fracture,the crack tip is blunted due to the development of the process zone in the near-tip area.In th...Hydraulic fracture is important in unconventional oil and gas exploration.During the propagation of the hydraulic fracture,the crack tip is blunted due to the development of the process zone in the near-tip area.In this study,the blunting of the hydraulic fracture in polymethyl methacrylate specimens due to multi-timescale stress concentration is investigated.The ratio of the initiation toughness to the arrest toughness of the blunted hydraulic fracture is measured using both the dynamic and the static methods.Results show that a hydraulic fracture can be blunted with the time span of stress concentration from 1 ms to 600 s.It is also shown that the blunting of hydraulic fracture is a highly localized process.The morphology of the blunted crack depends on the stress distribution in the vicinity of the crack tip.展开更多
A multi-casing structure in drilling engineering can be considered as an inhomogeneous body consisting of many different materials. The mechanical behavior of the inhomogeneous body in an infinite domain is very com- ...A multi-casing structure in drilling engineering can be considered as an inhomogeneous body consisting of many different materials. The mechanical behavior of the inhomogeneous body in an infinite domain is very com- plicated. In this paper, a detailed expression about the fictitious stress method of the boundary element method （BEM） is demonstrated for the inhomogeneous body. Then the fictitious stress method is deployed to investigate the stresses for the multi-casing structure under non-uniform loading conditions and an irregular wellbore. Three examples of the multi-casing structure in the borehole imply the high effectiveness of BEM for complex geometries related to the borehole in an infinite formation. The effects of casing eccentricity and the interfacial gap on the stress field are discussed. The eccentric casing takes the potential yield when the eccentric orientation is along the direction of Sh. Under different eccentric orientations, the yon Mises stress in the casing increases with increasing degree of eccentricity. The radial stress in the multi-casing structure is always continuous along the radius, but the circumferential stress is discontinuous at the interface. The radial stress decreases and the circumferential stress increases with the increasing of the interfacial gap between the adjacent materials.展开更多
Acute and infected wounds resulting from accidents,battlefield trauma,or surgical interventions have become a global healthcare burden due to the complex bacterial infection environment.However,conventional gauze dres...Acute and infected wounds resulting from accidents,battlefield trauma,or surgical interventions have become a global healthcare burden due to the complex bacterial infection environment.However,conventional gauze dressings present insufficient contact with irregular wounds and lack antibacterial activity against multi-drug-resistant bacteria.In this study,we develop in situ nanofibrous dressings tailored tofit wounds of various shapes and sizes while providing nanoscale comfort and excellent antibacterial properties.Our approach involves the fabrication of these dressings using a handheld electrospinning device that allows for the direct depo-sition of nanofiber dressings onto specific irregular wound sites,resulting in perfect conformal wound closure without any mismatch in 2 min.The nanofibrous dressings are loaded with multi-armed antibiotics that exhibit outstanding antibacterial activ-ity against Staphylococcus aureus(S.aureus)and methicillin-resistant S.aureus.Compared to conventional vancomycin,this in situ nanofibrous dressing shows great antibacterial performance against up to 98%of multi-drug-resistant bacteria.In vitro and in vivo experiments demonstrate the ability of in situ nanofibrous dressings to prevent multi-drug-resistant bacterial infection,greatly alleviate inflammation,and promote wound healing.Ourfindings highlight the potential of these personalized nanofibrous dressings for clinical applications,including emergency,accident,and surgical healthcare treatment.展开更多
Fully bioresorbable vascular scaffolds(BVSs)aim to overcome the limitations of metallic drug-eluting stents(DESs).However,polymer-based BVSs,such as Abbott’s Absorb,the only US FDA-approved BVS,have had limited use d...Fully bioresorbable vascular scaffolds(BVSs)aim to overcome the limitations of metallic drug-eluting stents(DESs).However,polymer-based BVSs,such as Abbott’s Absorb,the only US FDA-approved BVS,have had limited use due to increased strut thickness(157μm for Absorb),exacerbated tissue inflammation,and increased risk of major cardiac events leading to inferior clinical performance when compared to metallic DESs.Herein we report the development of a drug-eluting BVS(DE-BVS)through the innovative use of a photopolymerizable,citrate-based biomaterial and a high-precision additive manufacturing process.BVS with a clinically relevant strut thickness of 62μm can be produced in a high-throughput manner,i.e.one BVS per minute,and controlled release of the anti-restenosis drug everolimus can be achieved by engineering the structure of polymer coatings to fabricate drug-eluting BVS.We achieved the successful deployment of BVSs and DE-BVSs in swine coronary arteries using a custom-built balloon catheter and BVS delivery system and confirmed BVS safety and efficacy regarding maintenance of vessel patency for 28 days,observing an inflammation profile for BVS and DE-BVS that was comparable to the commercial XIENCE^(TM)DES(Abbott Vascular).展开更多
Background:The oncological safety of transanal total mesorectal excision(taTME)remains uncertain,and its special surgical approach may contribute to tumor cell dissemination.Thus,we conducted a study to investigate th...Background:The oncological safety of transanal total mesorectal excision(taTME)remains uncertain,and its special surgical approach may contribute to tumor cell dissemination.Thus,we conducted a study to investigate the impact of surgical approach on circulating tumor cell(CTC)counts and phenotypes in rectal cancer.Methods:This is a prospective randomized controlled study(ClinicalTrials:NCT05109130).The patients were randomized to either the taTME(n?49)or laparoscopic TME(laTME)(n=48)groups.Blood samples were collected from the central vein to measure CTC counts and phenotypes at three time points:preoperative(t1),immediately post-tumor removal(t2),and one week post-surgery(t3).The effect of surgical procedure on CTCs at each time point was analyzed,with the primary endpoint being the change in CTC counts from t1 to t3 for each surgical approach.This study adheres to Consolidated Standards of Reporting Trials Guidelines.Results:The baseline clinicopathologic characteristics of the laTME and taTME groups were balanced.The change in CTC count from t1 to t3 was 1.81±5.66 in the laTME group and 2.18±5.53 in the taTME group.The taTME surgery was non-inferior to laTME in terms of changing CTC counts(mean difference[MD]:−0.371;95%confidence interval[CI]:−2.626 to 1.883,upper-sided 95%CI of 1.883<2,non-inferiority boundary value).Compared with that at t1,the CTC count at t2 did not change significantly.However,higher CTC counts were detected at t3 than at t2 in the taTME(P=0.032)and laTME(P?0.003)groups.From t1 to t3,CTC counts significantly in-creased in both the taTME(P=0.008)and laTME(P?0.031)groups.There were no significant differences in CTC phenotype changes between the two groups from t1 to t3.Conclusions:Compared with laTME,taTME did not affect CTC counts and phenotypes.Our findings indicate that taTME is not infe-rior to laTME in terms of CTC changes from an oncological perspective.展开更多
Biomaterial surfaces with satisfied antibacterial activity and appropriate cytocompatibility are a pressing clinical need for orthopedic and dental implants.Fluorinecontaining biomaterials have been demonstrated to ob...Biomaterial surfaces with satisfied antibacterial activity and appropriate cytocompatibility are a pressing clinical need for orthopedic and dental implants.Fluorinecontaining biomaterials have been demonstrated to obtain antibacterial activity and osteogenic property,while the effect of fluorine chemical compositions on antibacterial property and cytocompatibility is rarely studied.To this end,the coatings with different fluorine chemical compositions on titanium surface were prepared by plasma treatment to verify the antibacterial ability and cytocompatibility of fluorinated surfaces.Their antibacterial ability was evaluated by using Staphylococcus aureus,and the cell compatibility was investigated with MC3T3-E1 cells in vitro.The results show that both fluorocarbon coating and metal fluorides coating exhibited a hydrophilic and nano-scaled roughness.Rather than the fluorocarbon coating,the coating composed of metal fluorides presented satisfied bactericide effect and excellent cytocompatibility.The antibacterial mechanism is associated with the metal fluorides and released fluoride ion.This work would provide novel sight in optimizing the surface modification method of fluorinated biomaterials for biomedical applications.展开更多
In this paper,a silvered gradient nanostructured(GNS)layer was successfully fabricated on Ti6Al4V surface by means of surface ultrasonic rolling treatment(SURT)combined with silvering process.Surface characteristics,m...In this paper,a silvered gradient nanostructured(GNS)layer was successfully fabricated on Ti6Al4V surface by means of surface ultrasonic rolling treatment(SURT)combined with silvering process.Surface characteristics,mechanical properties,corrosion resistance,antibacterial ability and cytotoxicity of GNS Ag/Ti6Al4V were investigated in comparison with those of coarse-grained(CG)and GNS Ti6Al4V samples.Owing to the greatly enhanced diffusion kinetics of Ag in the GNS layer,surface silvering on GNS Ti6Al4V was achieved at a relatively low temperature(500℃),and the release rate of Ag^(+)was substantially accelerated,which endowed GNS Ag/Ti6Al4V with excellent antibacterial property.Moreover,improved wear and corrosion resistance of GNS Ag/Ti6Al4V can be achieved without cytotoxicity,indicating excellent bioadaptability.展开更多
基金funded by the National Natural Science Foundation of China(General Program:No.52074314,No.U19B6003-05)National Key Research and Development Program of China(2019YFA0708303-05)。
文摘Accurate prediction of formation pore pressure is essential to predict fluid flow and manage hydrocarbon production in petroleum engineering.Recent deep learning technique has been receiving more interest due to the great potential to deal with pore pressure prediction.However,most of the traditional deep learning models are less efficient to address generalization problems.To fill this technical gap,in this work,we developed a new adaptive physics-informed deep learning model with high generalization capability to predict pore pressure values directly from seismic data.Specifically,the new model,named CGP-NN,consists of a novel parametric features extraction approach(1DCPP),a stacked multilayer gated recurrent model(multilayer GRU),and an adaptive physics-informed loss function.Through machine training,the developed model can automatically select the optimal physical model to constrain the results for each pore pressure prediction.The CGP-NN model has the best generalization when the physicsrelated metricλ=0.5.A hybrid approach combining Eaton and Bowers methods is also proposed to build machine-learnable labels for solving the problem of few labels.To validate the developed model and methodology,a case study on a complex reservoir in Tarim Basin was further performed to demonstrate the high accuracy on the pore pressure prediction of new wells along with the strong generalization ability.The adaptive physics-informed deep learning approach presented here has potential application in the prediction of pore pressures coupled with multiple genesis mechanisms using seismic data.
基金the Project Support of NSFC(No.U19B6003-05 and No.52074314)。
文摘A method for in-situ stress measurement via fiber optics was proposed. The method utilizes the relationship between rock mass elastic parameters and in-situ stress. The approach offers the advantage of long-term stress measurements with high spatial resolution and frequency, significantly enhancing the ability to measure in-situ stress. The sensing casing, spirally wrapped with fiber optic, is cemented into the formation to establish a formation sensing nerve. Injecting fluid into the casing generates strain disturbance, establishing the relationship between rock mass properties and treatment pressure.Moreover, an optimization algorithm is established to invert the elastic parameters of formation via fiber optic strains. In the first part of this paper series, we established the theoretical basis for the inverse differential strain analysis method for in-situ stress measurement, which was subsequently verified using an analytical model. This paper is the fundamental basis for the inverse differential strain analysis method.
基金supported by CNPC Key Core Technology Research Projects (2022ZG06)project funded by China Postdoctoral Science Foundation (2021M693508)Basic research and strategic reserve technology research fund project of institutes directly under CNPC.
文摘The efficient development and exploitation of shale oil depends on long-distance horizontal wells. As the degreeof cleaning of the wellbore plays a key role in these processes, in this study, this problem is investigated experimentallyby focusing on the dimensionless cuttings bed height. A method is proposed to calculate the horizontalwellhydraulic extension taking into account the influence of the wellbore cleaning degree on the wellborepressure distribution and assess the effect of a variety of factors such as the bottom hole pressure, the circulatingpressure drop, the drilling pump performance and the formation properties. The analysis shows that the hydraulicextension of horizontal wells decreases with an increase in the cuttings bed height, and the higher the displacementof drilling fluid, the faster the hydraulic extension declines. The annular pressure drop of the horizontalsection increases with the increase of the cuttings bed height, resulting in a higher bottom-hole pressure. Severalarguments are provided to guide the safe drilling of shale oil horizontal wells and overcome the limits of currenttechnological approaches.
基金the financial support by National Natural Science Foundation of China(No.52334001)。
文摘Shale reservoirs contain numerous bedding fractures,making the formation of complex fracture networks during fracturing a persistent technical challenge in evaluating shale fracture morphology.Distributed optical fiber sensing technology can effectively capture the process of fracture initiation and propagation,yet the evaluation method for the initiation and propagation of bedding fractures remains immature.This study integrates a distributed optical fiber sensing device based on optical frequency domain reflectometry(OFDR)with a large-scale true tri-axial fracturing physical simulation apparatus to conduct real-time monitoring experiments on shale samples from the Lianggaoshan Formation in the Sichuan Basin,where bedding is well-developed.The experimental results demonstrate that two bedding fractures in the shale sample initiated and propagated.The evolution characteristics of fiber-optic strain in a horizontal adjacent well,induced by the initiation and propagation of bedding fractures,are characterized by the appearance of a tensile strain convergence zone in the middle of the optical fiber,flanked by two compressive strain convergence zones.The initiation and propagation of the distal bedding fracture causes the fiber-optic strain in the horizontal adjacent well to superimpose,with the asymmetric propagation of the bedding fracture leading to an asymmetric tensile strain convergence zone in the optical fiber.Utilizing a finite element method coupled with a cohesive element approach,a forward model of fiber-optic strain in the horizontal adjacent well induced by the initiation and propagation of hydraulic fracturing bedding fractures was constructed.Numerical simulation analyses were conducted to evaluate the evolution of fiber-optic strain in the horizontal adjacent well,confirming the correctness of the observed evolution characteristics.The presence of a"wedge-shaped"tensile strain convergence zone in the fiber-optic strain waterfall plot,accompanied by two compressive strain convergence zones,indicates the initiation and propagation of bedding fractures during the fracturing process.These findings provide valuable insights for interpreting distributed fiber-optic data in shale fracturing field applications.
基金Natural Science Foundation Project of Chongqing(No.CSTB2023NSCQ-MSX0343)Science and Technology Research Programme of Chongqing Municipal Education Commission(No.KJZD-K202101105)+2 种基金Humanities and Social Sciences Research Programme of Chongqing Municipal Education Commission(No.22SKGH302)Chongqing Municipal Entrepreneurship and Innovation Support Project for Returned Overseas(No.cx2021087)National Natural Science Foundation of China(No.61702063).
文摘Exploiting the hierarchical dependence behind user behaviour is critical for click-through rate (CRT) prediction in recommender systems. Existing methods apply attention mechanisms to obtain the weights of items;however, the authors argue that deterministic attention mechanisms cannot capture the hierarchical dependence between user behaviours because they treat each user behaviour as an independent individual and cannot accurately express users' flexible and changeable interests. To tackle this issue, the authors introduce the Bayesian attention to the CTR prediction model, which treats attention weights as data-dependent local random variables and learns their distribution by approximating their posterior distribution. Specifically, the prior knowledge is constructed into the attention weight distribution, and then the posterior inference is utilised to capture the implicit and flexible user intentions. Extensive experiments on public datasets demonstrate that our algorithm outperforms state-of-the-art algorithms. Empirical evidence shows that random attention weights can predict user intentions better than deterministic ones.
基金the support from the National Science and Technology Major Projects of China(Grant No.2016ZX05066)Major Program of National Natural Science Foundation of China(Grant No.51490650)PetroChina Innovation Foundation(No.2018D-5007-0307)
文摘Whether hydraulic fractures could connect multiple gas zones in the vertical plane is the key to fracturing treatment to jointly exploit coalbed methane and tight sandstone gas through integrative hydraulic fracturing in tight sandstone–coal interbedded formations. Laboratory true triaxial hydraulic fracturing experiments were conducted on layered specimens with di erent combination types of natural sandstone and coal to simulate the propagation behavior of hydraulic fractures. The effects of the fracture initiation position, fracturing fluid viscosity and injection rate were discussed. The results showed that di erent fracture morphologies could be found. When initiating from coal seams, three patterns of fracture initiation and propagation were obtained:(1) The main hydraulic fracture initiated and propagated along the natural fractures and then diverged due to the effects of in situ stress and formed secondary fractures.(2) The hydraulic fracture initiated and propagated in the direction of the maximum horizontal stress.(3) Multiple fractures initiated and propagated at the same time. With the same fracturing fluid viscosity and injection rate, the hydraulic fractures initiating in sandstones had greater chances than those in coal seams to penetrate interfaces and enter neighboring layers. Excessively small or large fracturing fluid viscosity and injection rate would do harm to the vertical extension height of the induced fracture and improvement of the stimulated reservoir volume. Compared with operation parameters(fracturing fluid viscosity and injection rate), the natural weak planes in coals were considered to be the key factor that a ected the fracture propagation path. The experimental results would make some contributions to the development of tight sandstone–coal interbedded reservoirs.
基金supported by Health and Family Planning Commission of Hainan Province,China,Scientific Research Project(Grant No.14A210207)
文摘Objective:To observe dynamic changes of levels of monocyte chemotactic protein-1(MCP-1),tumor necrosis factor-α(TNF-α) and interleukin-8(IL-8) in patients with acute pancreatitis and to investigate its evaluation value on the severity of acute pancreatitis.Methods:A total of 109 patients with acute pancreatitis admitted were divided into mild acute pancreatitis group(MAP group,42 cases),moderately severe acute pancreatitis(MSAP group,35 cases)and severe acute pancreatitis(SAP group,32 cases).ELISA was used to detect the serum levels of MCP-1,TNF-α and IL-8 of patients at day 1,day 4 and day 7 of admission to hospital.Results:The serum levels of MCP-1,TNF-α and IL-8 from MAP group,MSAP group and SAP group at day 1 of admission to hospital all significantly increased.There was a significant difference between MAP group and control group,MSAP group and MAP group,SAP group and MSAP group(P<0.05).The serum concentrations of IL-8 from MASP group and SAP group obviously increased at day 1,and there was significant difference between MASP group and MAP group,SAP group and MSAP group(P<0.05),while the difference between MAP group and control group was not obvious(P>0.05);The serum concentrations of MCP-1,TNF-α and IL-8 from MAP group all reached the highest level at day 4,which were significantly higher than the detection levels at day 1.In MSAP group and SAP group,the serum concentrations of MCP-1,TNF-α and IL-8 were the highest at day 1,which were significantly higher than the detection levels at day 4 and 7.At each detecting timing,the serum concentrations of MCP-1,TNF-α and IL-8 from MSAP group and SAP group were all higher than those of MAP group and MSAP group,respectively.Conclusions:The dynamic changes of serum levels of MCP-1,TNF-α and IL-8 in patients with acute pancreatitis have their rules,and the change rule of MAP group was different with that of MSAP and SAP group,which showed the reference value for the diagnosis and illness severity evaluation of acute pancreatitis.
基金the support from the China National Science and Technology Major Project"Changning-Weiyuan shale gas development demonstration project"(2016ZX05062)the support from the China National Petroleum Corporation:"Research on Influencing Factors of Gas Hydrate Sand Production and Experimental Design"(No.CPETQ201921)。
文摘Hydraulic fracture is important in unconventional oil and gas exploration.During the propagation of the hydraulic fracture,the crack tip is blunted due to the development of the process zone in the near-tip area.In this study,the blunting of the hydraulic fracture in polymethyl methacrylate specimens due to multi-timescale stress concentration is investigated.The ratio of the initiation toughness to the arrest toughness of the blunted hydraulic fracture is measured using both the dynamic and the static methods.Results show that a hydraulic fracture can be blunted with the time span of stress concentration from 1 ms to 600 s.It is also shown that the blunting of hydraulic fracture is a highly localized process.The morphology of the blunted crack depends on the stress distribution in the vicinity of the crack tip.
基金supported by the China National High Technology Research and Development Program 863 (Grant No. 2013AA064503)The China Scholarship Council
文摘A multi-casing structure in drilling engineering can be considered as an inhomogeneous body consisting of many different materials. The mechanical behavior of the inhomogeneous body in an infinite domain is very com- plicated. In this paper, a detailed expression about the fictitious stress method of the boundary element method （BEM） is demonstrated for the inhomogeneous body. Then the fictitious stress method is deployed to investigate the stresses for the multi-casing structure under non-uniform loading conditions and an irregular wellbore. Three examples of the multi-casing structure in the borehole imply the high effectiveness of BEM for complex geometries related to the borehole in an infinite formation. The effects of casing eccentricity and the interfacial gap on the stress field are discussed. The eccentric casing takes the potential yield when the eccentric orientation is along the direction of Sh. Under different eccentric orientations, the yon Mises stress in the casing increases with increasing degree of eccentricity. The radial stress in the multi-casing structure is always continuous along the radius, but the circumferential stress is discontinuous at the interface. The radial stress decreases and the circumferential stress increases with the increasing of the interfacial gap between the adjacent materials.
基金National Key R&D Program of China,Grant/Award Number:2022YFB3804700Guangdong Innovative and Entrepreneurial Research Team Program,Grant/Award Number:2019ZT08Y191+5 种基金Shenzhen Science and Technology Program,Grant/Award Numbers:KQTD20190929172743294,JCYJ20200109141231365National Key Research and Development Program of China,Grant/Award Number:2022YFB3804700Guangdong Major Talent Introduction Project,Grant/Award Number:2019CX01Y196Beijing Institute of Genomics,Chinese Academy of Sciences,Grant/Award Number:QYZDJ-SSW-SLH039Shenzhen Key Laboratory of Smart Healthcare Engineering,Grant/Award Number:ZDSYS20200811144003009National Natural Science Foundation of China,Grant/Award Numbers:21535001,21761142006,22234004,52203243,81730051。
文摘Acute and infected wounds resulting from accidents,battlefield trauma,or surgical interventions have become a global healthcare burden due to the complex bacterial infection environment.However,conventional gauze dressings present insufficient contact with irregular wounds and lack antibacterial activity against multi-drug-resistant bacteria.In this study,we develop in situ nanofibrous dressings tailored tofit wounds of various shapes and sizes while providing nanoscale comfort and excellent antibacterial properties.Our approach involves the fabrication of these dressings using a handheld electrospinning device that allows for the direct depo-sition of nanofiber dressings onto specific irregular wound sites,resulting in perfect conformal wound closure without any mismatch in 2 min.The nanofibrous dressings are loaded with multi-armed antibiotics that exhibit outstanding antibacterial activ-ity against Staphylococcus aureus(S.aureus)and methicillin-resistant S.aureus.Compared to conventional vancomycin,this in situ nanofibrous dressing shows great antibacterial performance against up to 98%of multi-drug-resistant bacteria.In vitro and in vivo experiments demonstrate the ability of in situ nanofibrous dressings to prevent multi-drug-resistant bacterial infection,greatly alleviate inflammation,and promote wound healing.Ourfindings highlight the potential of these personalized nanofibrous dressings for clinical applications,including emergency,accident,and surgical healthcare treatment.
基金supported by the National Institutes of Health,United States(Grant:R01HL141933)Y.Ding was supported in part by the Center for Advanced Regenerative Engineering and American Heart Association Career Development Award(AHA,Grant:852772).The authors gratefully acknowledge Connor Alexander Moore and Casey Tan for their technical support in schematic illustration and data analysis,respectively.
文摘Fully bioresorbable vascular scaffolds(BVSs)aim to overcome the limitations of metallic drug-eluting stents(DESs).However,polymer-based BVSs,such as Abbott’s Absorb,the only US FDA-approved BVS,have had limited use due to increased strut thickness(157μm for Absorb),exacerbated tissue inflammation,and increased risk of major cardiac events leading to inferior clinical performance when compared to metallic DESs.Herein we report the development of a drug-eluting BVS(DE-BVS)through the innovative use of a photopolymerizable,citrate-based biomaterial and a high-precision additive manufacturing process.BVS with a clinically relevant strut thickness of 62μm can be produced in a high-throughput manner,i.e.one BVS per minute,and controlled release of the anti-restenosis drug everolimus can be achieved by engineering the structure of polymer coatings to fabricate drug-eluting BVS.We achieved the successful deployment of BVSs and DE-BVSs in swine coronary arteries using a custom-built balloon catheter and BVS delivery system and confirmed BVS safety and efficacy regarding maintenance of vessel patency for 28 days,observing an inflammation profile for BVS and DE-BVS that was comparable to the commercial XIENCE^(TM)DES(Abbott Vascular).
基金supported by National Key Clinical Discipline,The Program of Guangdong Provincial Clinical Research Center for Digestive Diseases[2020B1111170004]Science and Technology Key Research and Development Plan Project of Guangzhou(China)[202103000072]+3 种基金Natural Science Foundation of Guangdong Province(China)[2018A030313621]Science and Technology Projects in Guangzhou[202206010062]Sun Yat-sen University Clinical Research 5010 Program[2016005]Shenzhen“San Ming Projects”Research[Grant No.lc202002].
文摘Background:The oncological safety of transanal total mesorectal excision(taTME)remains uncertain,and its special surgical approach may contribute to tumor cell dissemination.Thus,we conducted a study to investigate the impact of surgical approach on circulating tumor cell(CTC)counts and phenotypes in rectal cancer.Methods:This is a prospective randomized controlled study(ClinicalTrials:NCT05109130).The patients were randomized to either the taTME(n?49)or laparoscopic TME(laTME)(n=48)groups.Blood samples were collected from the central vein to measure CTC counts and phenotypes at three time points:preoperative(t1),immediately post-tumor removal(t2),and one week post-surgery(t3).The effect of surgical procedure on CTCs at each time point was analyzed,with the primary endpoint being the change in CTC counts from t1 to t3 for each surgical approach.This study adheres to Consolidated Standards of Reporting Trials Guidelines.Results:The baseline clinicopathologic characteristics of the laTME and taTME groups were balanced.The change in CTC count from t1 to t3 was 1.81±5.66 in the laTME group and 2.18±5.53 in the taTME group.The taTME surgery was non-inferior to laTME in terms of changing CTC counts(mean difference[MD]:−0.371;95%confidence interval[CI]:−2.626 to 1.883,upper-sided 95%CI of 1.883<2,non-inferiority boundary value).Compared with that at t1,the CTC count at t2 did not change significantly.However,higher CTC counts were detected at t3 than at t2 in the taTME(P=0.032)and laTME(P?0.003)groups.From t1 to t3,CTC counts significantly in-creased in both the taTME(P=0.008)and laTME(P?0.031)groups.There were no significant differences in CTC phenotype changes between the two groups from t1 to t3.Conclusions:Compared with laTME,taTME did not affect CTC counts and phenotypes.Our findings indicate that taTME is not infe-rior to laTME in terms of CTC changes from an oncological perspective.
基金This study was financially supported by the National Natural Science Foundation of China(No.52001122,51801064 and 51961012)Jiangxi Outstanding Young Talents Program(No.20192BCB23014),and Jiangxi Key Research and Development Program(No.20203BBE53050).
文摘Biomaterial surfaces with satisfied antibacterial activity and appropriate cytocompatibility are a pressing clinical need for orthopedic and dental implants.Fluorinecontaining biomaterials have been demonstrated to obtain antibacterial activity and osteogenic property,while the effect of fluorine chemical compositions on antibacterial property and cytocompatibility is rarely studied.To this end,the coatings with different fluorine chemical compositions on titanium surface were prepared by plasma treatment to verify the antibacterial ability and cytocompatibility of fluorinated surfaces.Their antibacterial ability was evaluated by using Staphylococcus aureus,and the cell compatibility was investigated with MC3T3-E1 cells in vitro.The results show that both fluorocarbon coating and metal fluorides coating exhibited a hydrophilic and nano-scaled roughness.Rather than the fluorocarbon coating,the coating composed of metal fluorides presented satisfied bactericide effect and excellent cytocompatibility.The antibacterial mechanism is associated with the metal fluorides and released fluoride ion.This work would provide novel sight in optimizing the surface modification method of fluorinated biomaterials for biomedical applications.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51801064,51961012 and 52001122)Jiangxi Outstanding Young Talents Program(No.20192BCB23014)Jiangxi Key Research and Development Program(No.20203BBE53050).
文摘In this paper,a silvered gradient nanostructured(GNS)layer was successfully fabricated on Ti6Al4V surface by means of surface ultrasonic rolling treatment(SURT)combined with silvering process.Surface characteristics,mechanical properties,corrosion resistance,antibacterial ability and cytotoxicity of GNS Ag/Ti6Al4V were investigated in comparison with those of coarse-grained(CG)and GNS Ti6Al4V samples.Owing to the greatly enhanced diffusion kinetics of Ag in the GNS layer,surface silvering on GNS Ti6Al4V was achieved at a relatively low temperature(500℃),and the release rate of Ag^(+)was substantially accelerated,which endowed GNS Ag/Ti6Al4V with excellent antibacterial property.Moreover,improved wear and corrosion resistance of GNS Ag/Ti6Al4V can be achieved without cytotoxicity,indicating excellent bioadaptability.
