Based on the construction of high risk tunnels in Guiguang-Guangzhou high-speed railway, several new technologies were developed for high-risk tunnel con- struction. First, an integrated advanced geological predic- ti...Based on the construction of high risk tunnels in Guiguang-Guangzhou high-speed railway, several new technologies were developed for high-risk tunnel con- struction. First, an integrated advanced geological predic- tion was developed for tunneling in karst area. Then, a new system of ventilation by involving the dedusting technol- ogy was proposed and used in the field, which received a good air quality. Finally, a method to minimize the dis- tance between the working face and the invert installation was proposed by optimizing the invert installation and adopting the micro bench method. Applying the method to the project obtained an excellent result. The achievement obtained for this study would be able to provide a valuable reference to similar projects in the future.展开更多
Surrounding rock deterioration and large deformation have always been a significant difficulty in designing and constructing tunnels in soft rock.The key lies in real-time perception and quantitative assessment of the...Surrounding rock deterioration and large deformation have always been a significant difficulty in designing and constructing tunnels in soft rock.The key lies in real-time perception and quantitative assessment of the damaged area around the tunnel.An in situ microseismic(MS)monitoring system is established in the plateau soft tock tunnel.This technique facilitates spatiotemporal monitoring of the rock mass's fracturing expansion and squeezing deformation,which agree well with field convergence deformation results.The formation mechanisms of progressive failure evolution of soft rock tunnels were discussed and analyzed with MS data and numerical results.The results demonstrate that:(1)Localized stress concentration and layered rock result in significant asymmetry in micro-fractures propagation in the tunnel radial section.As excavation continues,the fracture extension area extends into the deep surrounding rockmass on the east side affected by the weak bedding;(2)Tunnel excavation and long-term deformation can induce tensile shear action on the rock mass,vertical tension fractures(account for 45%)exist in deep rockmass,which play a crucial role in controlling the macroscopic failure of surrounding rock;and(3)Based on the radiated MS energy,a three-dimensional model was created to visualize the damage zone of the tunnel surrounding rock.The model depicted varying degrees of damage,and three high damage zones were identified.Generally,the depth of high damage zone ranged from 4 m to 12 m.This study may be a valuable reference for the warning and controlling of large deformations in similar projects.展开更多
The construction of the new tunnel under the existing railway will break the original stress balance in the engineering area, resulting in the secondary redistribution of surrounding rock stress. The large amount of e...The construction of the new tunnel under the existing railway will break the original stress balance in the engineering area, resulting in the secondary redistribution of surrounding rock stress. The large amount of excavation unloading of the soil below is also easy to induce the uneven settlement deformation of the existing structure above, affecting the safety of driving. Based on the shield tunnel project between Caoqiao Station and Lize Business District Station of Beijing Metro, this paper restores the construction site by constructing the finite element numerical model of the project area, calculates and analyzes the deformation and stress of the existing railway structure before and after the construction of the tunnel, and determines the safety impact of the new structure on the existing railway. The results show that the shield tunnel undercrossing construction will cause the “concave” settlement of the railway subgrade above. Under the condition of grouting reinforcement, the “concave” settlement curve is slower and the distribution range is wider. With the advancement of the construction step, the settlement deformation of the subgrade gradually increases. When the tunnel approaches and passes directly below the subgrade, the settlement deformation curve of the subgrade changes from slow to steep. After the tunnel passes away, the curve changes from steep to slow, and the deformation of the subgrade reaches the maximum after the tunnel is connected. Under the grouting condition, the maximum settlement deformation of the subgrade is 2.08 mm, which is about 45% of the settlement deformation of the subgrade under the non-grouting condition. The ground grouting reinforcement can effectively control the subgrade settlement, and the field monitoring verifies the rationality of the calculation results. After the tunnel passes underneath, the most unfavorable section of the existing railway frame bridge is located at the top plate of the structure, and the maximum crack width is 0.178 mm. After grouting reinforcement, the stress environment of the structure is improved, the crack width generated by the structure is smaller, the reinforcement area required for calculation is less, and the structural safety meets the requirements.展开更多
Objective: Stroke is perceived as a serious illness although it is preventable, and lifestyle alterations can be made to reduce its risk. Improvement of stroke care should be achieved through awareness of public, espe...Objective: Stroke is perceived as a serious illness although it is preventable, and lifestyle alterations can be made to reduce its risk. Improvement of stroke care should be achieved through awareness of public, especially through high-risk group. Henceforth, the aim of this study was to evaluate the effect of nursing intervention on improving awareness of high-risk people about stroke prevention. Methods: A quasi-experimental design was used to carry out this study, where a purposive sample of 80 adult patients at high risk for stroke were enrolled while they were attending the out-patient clinics of Zagazig University Hospitals for follow-up treatment;they were divided into two groups: case (40 patients) and control (40 patients). An interview questionnaire was used to assess patients’ knowledge regarding warning signs, risk factors, and immediate treatment;attitude;and their practice for prevention for stroke at pretest and posttest. Results: The study revealed the poor level of knowledge, bad level of preventive behavior, and negative attitude regarding stroke prevention at pre-intervention. However, after intervention, the high-risk people had fair level of knowledge with moderate practice for stroke prevention and positive attitude, with statistically significant difference between pre-post intervention and between the case and control groups. Conclusions: The study revealed that the nursing intervention seemed to change the knowledge, practice, and attitude of subjects regarding stroke prevention. This, in turn, implies that awareness of prevention of stroke and high-risk factor control could be important to reduce the burden of stroke in Egypt. Thus, further research on a larger scale is required to improve population knowledge and behavior for stroke prevention and control.展开更多
Objective:To explore the perspectives of high-risk pregnant women regarding the home care program for high-risk pregnancies.Methods:This qualitative study was conducted in a university hospital and 5 comprehensive hea...Objective:To explore the perspectives of high-risk pregnant women regarding the home care program for high-risk pregnancies.Methods:This qualitative study was conducted in a university hospital and 5 comprehensive health centers in Ahvaz,Iran,from February 2023 to July 2023.The sampling method used was purposive sampling considering the maximum possible diversity,which continued until data saturation.11 in-depth and semistructured interviews were conducted with high-risk pregnant women.Data were simultaneously analysed using Graneheim and Lundman content analysis by MAXQDA version 20 software.Results:Data analysis extracted 3 themes,12 categories,and 26 subcategories.The themes and categories were“high-risk pregnancy and related issues(pursuing treatment and paying attention to the high-risk situation by pregnant women,psychological aspect of high-risk pregnancy on pregnant women and caregivers,emotional and physical aspects of high-risk pregnancy,the consequences of high-risk pregnancy on the people around them and empowerment of high-risk pregnant women)”,“support dimension(family and community support for high-risk pregnant women)”,and“framework of program(acculturalization,means and equipment,security,manpower and the necessary arrangements for the home care)”.Conclusions:High-risk pregnancy affects various aspects of the lives of high-risk pregnant women and their families.Creating the necessary conditions for providing care at home plays a vital role in supporting high-risk pregnant women and removing related obstacles to receiving prenatal care in person.It will be especially beneficial for high-risk pregnant women in low-income areas.展开更多
The deformation caused by tunnel excavation is quite important for safety,especially when it is adjacent to the existing tunnel.Nevertheless,the investigation of deformation characteristics in overlapped curved shield...The deformation caused by tunnel excavation is quite important for safety,especially when it is adjacent to the existing tunnel.Nevertheless,the investigation of deformation characteristics in overlapped curved shield tunneling remains inadequate.The analytical solution for calculating the deformation of the ground and existing tunnel induced by overlapped curved shield tunneling is derived by the Mirror theory,Mindlin solution and Euler-Bernoulli-Pasternak model,subsequently validated through both finite element simulation and field monitoring.It is determined that the overcutting plays a crucial role in the ground settlement resulting from curved shield tunneling compared to straight shield tunneling.The longitudinal settlement distribution can be categorized into five areas,with the area near the tunnel surface experiencing the most dramatic settlement changes.The deformation of the existing tunnel varies most significantly with turning radius compared to tunnel clearance and grouting pressure,especially when the turning radius is less than 30 times the tunnel diameter.The tunnel crown exhibits larger displacement than the tunnel bottom,resulting in a distinctive‘vertical egg'shape.Furthermore,an optimized overcutting mode is proposed,involving precise control of the extension speed and angular velocity of the overcutting cutter,which effectively mitigates ground deformation,ensuring the protection of the existing tunnel during the construction.展开更多
Monitoring of the mechanical behavior of underwater shield tunnels is vital for ensuring their long-term structural stability.Typically determined by empirical or semi-empirical methods,the limited number of monitorin...Monitoring of the mechanical behavior of underwater shield tunnels is vital for ensuring their long-term structural stability.Typically determined by empirical or semi-empirical methods,the limited number of monitoring points and coarse monitoring schemes pose huge challenges in terms of capturing the complete mechanical state of the entire structure.Therefore,with the aim of optimizing the monitoring scheme,this study introduces a spatial deduction model for the stress distribution of the overall structure using a machine learning algorithm.Initially,clustering experiments were performed on a numerical data set to determine the typical positions of structural mechanical responses.Subsequently,supervised learning methods were applied to derive the data information across the entire surface by using the data from these typical positions,which allows flexibility in the number and combinations of these points.According to the evaluation results of the model under various conditions,the optimized number of monitoring points and their locations are determined.Experimental findings suggest that an excessive number of monitoring points results in information redundancy,thus diminishing the deduction capability.The primary positions for monitoring points are determined as the spandrel and hance of the tunnel structure,with the arch crown and inch arch serving as additional positions to enhance the monitoring network.Compared with common methods,the proposed model shows significantly improved characterization abilities,establishing its reliability for optimizing the monitoring scheme.展开更多
BACKGROUND Effective health management for high-risk stroke populations is essential.The hospital-community-home(HCH)collaborative health management(CHM)model leverages resources from hospitals,communities,and familie...BACKGROUND Effective health management for high-risk stroke populations is essential.The hospital-community-home(HCH)collaborative health management(CHM)model leverages resources from hospitals,communities,and families.By integrating patient information across these three domains,it facilitates the delivery of tailored guidance,health risk assessments,and three-in-one health education.AIM To explore the effects of the HCH-CHM model on stroke risk reduction in highrisk populations.METHODS In total,110 high-risk stroke patients screened in the community from January 2019 to January 2023 were enrolled,with 52 patients in the control group receiving routine health education and 58 in the observation group receiving HCH-CHM model interventions based on routine health education.Stroke awareness scores,health behavior levels,medication adherence,blood pressure,serum biochemical markers(systolic/diastolic blood pressure,total cholesterol,and triglyceride),and psychological measures(self-rating anxiety/depression scale)were evaluated and compared between groups.RESULTS The observation group showed statistically significant improvements in stroke awareness scores and health behavior levels compared to the control group(P<0.05),with notable enhancements in lifestyle and dietary habits(P<0.05)and reductions in postintervention systolic blood pressure,diastolic blood pressure,total cholesterol,triglyceride,self-rating anxiety scale,and self-rating depression scale scores(P<0.05).CONCLUSION The HCH-CHM model had a significant positive effect on high-risk stroke populations,effectively increasing disease awareness,improving health behavior and medication adherence,and appropriately ameliorating blood pressure,serum biochemical marker levels,and negative psychological symptoms.展开更多
BACKGROUND Inadequately controlled hypertension often leads to an increased cardiovascular death rate in type 2 diabetes mellitus(T2DM).It remains unclear whether systolic blood pressure(SBP)status of hypertension is ...BACKGROUND Inadequately controlled hypertension often leads to an increased cardiovascular death rate in type 2 diabetes mellitus(T2DM).It remains unclear whether systolic blood pressure(SBP)status of hypertension is related to coronary inflammation and plaques in T2DM.AIM To evaluate whether SBP variability(SBPV)and levels of hypertension are related to coronary inflammation and plaques in T2DM patients using coronary computed tomography angiography(CCTA).METHODS This retrospective study involved 881 T2DM patients with CCTA images,including 668 hypertension and 213 normotension patients.Hypertension patients were subgroup based on SBP status:(1)SBPV:Low(<8.96 mmHg)and high(≥8.96 mmHg)groups;and(2)SBP levels:Controlled(<140 mmHg)and uncontrolled(≥140 mmHg)groups.Pericoronary adipose tissue(PCAT)attenuation,high-risk plaques(HRPs)and obstructive stenosis(OS)were evaluated by CCTA.Propensity score matching was utilized to compare these CCTA findings for these groups.The impact of SBPV and SBP levels of hypertension on these CCTA findings in T2DM patients were evaluated by multivariate logistic regression and multivariable linear regression.RESULTS PCAT attenuation of the left anterior descending artery(LAD),any low attenuation plaque(LAP),any spotty calcification(SC),any positive remodeling(PR),and OS had significant differences between the hypertension group and the normotension group,as well as between the high SBPV or uncontrolled SBP group and the low SBPV or controlled SBP group(all P<0.05).Hypertension was independently positively correlated with LADPCAT attenuation(β=1.815,P=0.010),LAP(OR=1.612,P=0.019),SC(OR=1.665,P=0.013),PR(OR=1.549,P=0.033),and OS(OR=1.928,P=0.036)in all T2DM patients.Additionally,high SBPV and uncontrolled SBP were independently positively correlated with LAD-PCAT attenuation(high SBPV:β=1.673,P=0.048;uncontrolled SBP:β=2.370,P=0.004)and PR(high SBPV:OR=1.903,P=0.048;uncontrolled SBP:OR=2.230,P=0.013)in T2DM patients with hypertension.CONCLUSION Inadequately controlled hypertension,including high SBPV and/or uncontrolled SBP levels,may be related to increased coronary artery inflammation,HRPs,and OS in T2DM,leading to increased cardiovascular risk.Achieving both low SBPV and controlled SBP levels simultaneously,especially in individuals with T2DM and hypertension,warrants clinical attention.展开更多
With recent technological advancements,tunnel boring machines(TBM)have developed and exhibited high performance in large diameters and weak ground conditions.Tunnels are crucial structures that significantly influence...With recent technological advancements,tunnel boring machines(TBM)have developed and exhibited high performance in large diameters and weak ground conditions.Tunnels are crucial structures that significantly influence the timelines of highway and railway projects.Therefore,the construction of tunnels with TBMs becomes a preferred option.In this study,a comparative analysis between TBM and the New Austrian Tunneling Method(NATM)for tunnel construction is performed in the construction of the T1 tunnel with a diameter of 13 m,which is the longest tunnel in the E?me-Salihli section of Ankara-izmir High-Speed Railway Project(Türkiye).The selection of TBM type,measures taken in problematic sections,and application issues of TBM are discussed.The impact of correct description of geological and geotechnical conditions on both selection and performance of TBM is presented.An earth pressure balanced type TBM is chosen for the construction of the T1 tunnel.Because of the additional engineering measures taken before excavation in problematic areas,the tunnel was completed with great success within the initially planned timeframe.From this point of view,this study is an important case and may contribute to worldwide tunneling literature.展开更多
The seepage of groundwater and the strain-softening of rock mass in a submarine tunnel expand the plastic region of rock,thereby affecting its overall stability.It is therefore essential to study the stress and strain...The seepage of groundwater and the strain-softening of rock mass in a submarine tunnel expand the plastic region of rock,thereby affecting its overall stability.It is therefore essential to study the stress and strain fields in the rocks surrounding the submarine tunnel by considering the coupled effect of strainsoftening and seepage.However,the evolution equation for the hydro-mechanical parameters in the existing fully coupled solution is a uniform equation that is unable to reproduce the characteristics of rock mass in practice.In this study,an updated numerical procedure for the submarine tunnel is derived by coupling strain-softening and seepage effect based on the experimental results.According to the hydro-mechanical coupling theory,the hydro-mechanical parameters such as elastic modulus,Poisson's ratio,Biot's coefficient and permeability coefficient of rocks are characterized by the fitting equations derived from the experimental data.Then,the updated numerical procedure is deduced with the governing equations,boundary conditions,seepage equations and fitting equations.The updated numerical procedure is verified accurately compared with the previous analytical solution.By utilizing the updated numerical procedure,the characteristics of stress field and the influences of initial pore water pressure,Biot's coefficient,and permeability coefficient on the stress,displacement and water-inflow of the surrounding rocks are discussed.Regardless of the variations in hydro-mechanical parameters,the stress distribution has a similar trend.The initial permeability coefficient exerts the most significant influence on the stress field.With the increases in initial pore water pressure and Biot's coefficient,the plastic region expands,and the water-inflow and displacement increase accordingly.Given the fact that the stability of the tunnel is more sensitive to the seepage force controlled by the hydraulic parameters,it is suggested to dewater the ground above the submarine tunnel to control the initial pore water pressure.展开更多
In biological neural systems,noise is ubiquitous but does not affect the correct decisions made in the complex cognitive tasks.Decision-making in biological neural system is typically achieved by accumulating input in...In biological neural systems,noise is ubiquitous but does not affect the correct decisions made in the complex cognitive tasks.Decision-making in biological neural system is typically achieved by accumulating input information over a period of time.Inspired by recent developments in neurosciences,we design a decision-making module based on spintronic devices,utilizing superparamagnetic tunnel junctions as artificial neurons.The feasibility of this decision-making module is verified through circuit simulations.Taking a multi-layer perceptron as an example,the module significantly improves the accuracy of the perceptron in the handwritten digit recognition task.Furthermore,the spintronic decision-making module offers advantages over the conventional pooling methods,such as adaptive decision time,high performance and the absence of analog-to-digital conversion.The decision-making module is flexible to be integrated into artificial neural networks and provides a general yet effective solution to enhance performance against device noise.展开更多
Shield tunnel,composed of several segments,is widely used in urban underground engineering.When the tunnel is under load,relative displacement occurs between adjacent segments.In the past,distributed optical fiber sen...Shield tunnel,composed of several segments,is widely used in urban underground engineering.When the tunnel is under load,relative displacement occurs between adjacent segments.In the past,distributed optical fiber sensing technology was used to perform strain monitoring,but there is an urgent need to determine how to transform strain into displacement.In this study,optical frequency domain reflectometry was applied in laboratory tests.Aiming at the shear process and center settlement process of shield tunnel segments,two kinds of quantitative calculation methods were put forward to carry out a quantitative analysis.Meanwhile,the laboratory test process was simulated numerically utilizing the discrete element numerical analysis method.Optical fiber,an atypical geotechnical material,was innovatively applied for discrete element modeling and numerical simulation.The results show that the measured displacement of the dial gauge,the calculated results of the numerical model,and the displacement quantitatively calculated from the optical fiber data agree with each other in general.The latter two methods can potentially be utilized in engineering application of deformation monitoring at shield tunnel joints,but need to be further calibrated and adjusted in detail.展开更多
Manipulating and braiding Majorana zero modes(MZM)are a critical step toward realizing topological quantum computing.The primary challenge is controlling the vortex,which hosts the MZM,within a superconducting film in...Manipulating and braiding Majorana zero modes(MZM)are a critical step toward realizing topological quantum computing.The primary challenge is controlling the vortex,which hosts the MZM,within a superconducting film in a spatially precise manner.To address this,we developed a magnetic force-based vortex control technology using the STM system with a self-designed four-electrode piezo-scanner tube and investigated vortex manipulation on the NbSe_(2) superconducting film.We employed ferromagnetic tips to control the movement of vortex array induced by the tip's remanent magnetism.A magnetic core solenoid device was integrated into the STM system and a strong magnetic tip demagnetization technique was developed,providing a viable technical solution for further enabling single vortex manipulation.展开更多
The stratum lithology and geological structure of the highway tunnel in the mountainous areas of western China are complex,and the engineering geological conditions are complicated.When the highway tunnel passes throu...The stratum lithology and geological structure of the highway tunnel in the mountainous areas of western China are complex,and the engineering geological conditions are complicated.When the highway tunnel passes through different lithological strata,its structural design and construction technology are completely diff erent.Therefore,in order to support the tunnel design and construction,the tunnel survey Among them,the identifi cation of the contact boundary between magmatic rock and metamorphic rock and the grade of surrounding rock is very important.Through magnetotelluric survey of the Mupi tunnel of Jiuzhaigou-Mianyang highway on G8513 line,2D forward numerical simulation,1D,2D,3D inversion,and engineering geological analysis,it is revealed that the electrical characteristics of each layer,focusing on the identifi cation of the contact boundary between magmatic rock and metamorphic rock.This study provides the electrical characteristics of the magmatic rock and metamorphic rock contact boundary of the Mupi Tunnel.It is speculated that the boundary is revealed by the tunnel construction excavation,which verifies the correctness of the geophysical inversion model and provides a more detailed design basis for the tunnel design.I believe that taking the Mupi Tunnel survey as an example,through this research,it can provide detailed geophysical evidence for highway tunnels to distinguish between magmatic rock and metamorphic rock.展开更多
The recent upsurge in metro construction emphasizes the necessity of understanding the mechanical performance of metro shield tunnel subjected to the influence of ground fissures.In this study,a largescale experiment,...The recent upsurge in metro construction emphasizes the necessity of understanding the mechanical performance of metro shield tunnel subjected to the influence of ground fissures.In this study,a largescale experiment,in combination with numerical simulation,was conducted to investigate the influence of ground fissures on a metro shield tunnel.The results indicate that the lining contact pressure at the vault increases in the hanging wall while decreases in the footwall,resulting in a two-dimensional stress state of vertical shear and axial tension-compression,and simultaneous vertical dislocation and axial tilt for the segments around the ground fissure.In addition,the damage to curved bolts includes tensile yield,flexural yield,and shear twist,leading to obvious concrete lining damage,particularly at the vault,arch bottom,and hance,indicating that the joints in these positions are weak areas.The shield tunnel orthogonal to the ground fissure ultimately experiences shear failure,suggesting that the maximum actual dislocation of ground fissure that the structure can withstand is approximately 20 cm,and five segment rings in the hanging wall and six segment rings in the footwall also need to be reinforced.This study could provide a reference for metro design in ground fissure sites.展开更多
Carbon nanotubes(CNTs)have garnered great attention in recent years due to their outstanding electrical,thermal,and mechanical properties.The incorporation of small amounts of CNTs in polymers can substantially improv...Carbon nanotubes(CNTs)have garnered great attention in recent years due to their outstanding electrical,thermal,and mechanical properties.The incorporation of small amounts of CNTs in polymers can substantially improve the sensitivity of the polymer's electrical conductivity.This paper presents a modified Maxwell model to evaluate the electrical conductivity of CNTs-filled polymer composites by introducing a transition zone to account for the tunneling effect.In this modified Maxwell model,the CNTs-filled polymer composite is modeled as a three-phase composite,consisting of a matrix(polymer),inclusions(CNTs),and a transition zone(tunneling zone).The effective electrical conductivity(EEC)of the composite is calculated based on the volume fractions and electrical conductivities of the matrix,inclusions,and transition zone.The model's validity is confirmed through the use of available test data,which demonstrates its capability to accurately capture the nonlinear conductivity behavior observed in CNTs-polymer composites.This study offers valuable insights into the design of high-performance conductive polymer nanocomposites,and enhances the understanding of electrical conduction mechanisms in CNT-dispersed polymer composites.展开更多
Objective:To evaluate the impact of subcutaneous tunneling on peripherally inserted central catheters(PICCs)dislodgement and malposition.Dislodged or malpositioned PICCs can lead to improper treatment.The subcutaneous...Objective:To evaluate the impact of subcutaneous tunneling on peripherally inserted central catheters(PICCs)dislodgement and malposition.Dislodged or malpositioned PICCs can lead to improper treatment.The subcutaneous tunneling strategy may be effective,but there is insufficient evidence,and proximal movement has not been explored.Methods:We randomized 630 patients who needed PICCs placement to either the tunneled PICCs(experimental group)or the non-tunneled PICCs(control group).Dislodgement and malposition of the catheter were the primary outcomes,and catheter-related infection(CRI)and catheter-related thrombosis(CRT)were the secondary outcomes.Results:Subcutaneous tunneling does not significantly reduce distal catheter movement,but it significantly reduces proximal catheter movement(4.3%vs.9.9%,P=0.007),which may explain the lower incidence of CRI(2.0%vs.5.3%,P=0.030)and CRT(3.6%vs.12.5%,P<0.001).Conclusions:Although subcutaneous tunneling does not significantly improve catheter prolapse,it should still be used clinically because proximal catheter movement can be a more serious problem associated with CRI and CRT.展开更多
Background:Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality. While liver transplantation (LT) provides the best long-term survival, it is constrained by organ scarcity and strict criteria....Background:Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality. While liver transplantation (LT) provides the best long-term survival, it is constrained by organ scarcity and strict criteria. Liver resection (LR) is often the initial treatment for patients with solitary tumors and preserved liver function. The high recurrence rates associated with LR has prompted the exploration of sequential living donor liver transplantation (seq LDLT) after LR as a strategy for HCC patients with high-risk of recurrence.Methods:We analyzed data from 27 adult patients who underwent seq LDLT after LR for HCC at Kaohsiung Chang Gung Memorial Hospital (KCGMH) between June 1994 and December 2023. Patients were selected based on high-risk histopathological features post-LR or as part of downstaging strategy. Outcomes measured included overall survival (OS) and disease-free survival (DFS).Results:Among 765 HCC patients who underwent LDLT, 204 received LR before LDLT, and 27 underwent seqL DLT. Five patients (19%) underwent living donor liver transplantation (LDLT) following LR as a downstaging strategy while the rest received seqL DLT as a preemptive strategy. The median age was 53.5 years with 85%males. Chronic hepatitis B was the predominant underlying disease (74%). The 1-, 3-, and 5-year OS and DFS rates were 100%, 96.0%, 96.0%and 100%, 96.2%, 96.2%, respectively, with two patients experiencing HCC recurrence. One patient died from HCC recurrence. High-risk histopathological features included microvascular invasion (52%), satellite nodules (15%), multiple tumors (26%), tumors> 5 cm(19%), and a total tumor diameter> 10 cm (7%).Conclusions:Seq LDLT offers a promising, tailored approach for managing HCC with adverse histopathologic features. Combining seq LDLT, downstaging strategies, and multidisciplinary treatments can achieve satisfactory OS and DFS in carefully selected patients, highlighting the need for refined criteria to identify the best candidates.展开更多
A fault is a geological structure characterized by significant displacement of rock masses along a fault plane within the Earth's crust.The Yunnan Tabaiyi Tunnel intersects multiple fault zones,making tunnel const...A fault is a geological structure characterized by significant displacement of rock masses along a fault plane within the Earth's crust.The Yunnan Tabaiyi Tunnel intersects multiple fault zones,making tunnel construction in fault-prone areas particularly vulnerable to the effects of fault activity due to the complexities of the surrounding geological environment.To investigate the dynamic response characteristics of tunnel structures under varying surrounding rock conditions,a three-dimensional large-scale shaking table physical model test was conducted.This study also aimed to explore the damage mechanisms associated with the Tabaiyi Tunnel under seismic loading.The results demonstrate that poor quality surrounding rock enhances the seismic response of the tunnel.This effect is primarily attributed to the distribution characteristics of acceleration,dynamic strain,and dynamic soil pressure.A comparison between unidirectional and multi-directional(including vertical)seismic motions reveals that vertical seismic motion has a more significant impact on specific tunnel locations.Specifically,the maximum tensile stress is observed at the arch shoulder,with values ranging from 60 to 100 k Pa.Moreover,NPR(Non-Prestressed Reinforced)anchor cables exhibit a substantial constant resistance effect under low-amplitude seismic waves.However,when the input earthquake amplitude reaches 0.8g,local sliding occurs at the arch shoulder region of the NPR anchor cable.These findings underscore the importance of focusing on seismic mitigation measures in fault zones and reinforcing critical areas,such as the arch shoulders,in practical engineering applications.展开更多
文摘Based on the construction of high risk tunnels in Guiguang-Guangzhou high-speed railway, several new technologies were developed for high-risk tunnel con- struction. First, an integrated advanced geological predic- tion was developed for tunneling in karst area. Then, a new system of ventilation by involving the dedusting technol- ogy was proposed and used in the field, which received a good air quality. Finally, a method to minimize the dis- tance between the working face and the invert installation was proposed by optimizing the invert installation and adopting the micro bench method. Applying the method to the project obtained an excellent result. The achievement obtained for this study would be able to provide a valuable reference to similar projects in the future.
基金the funding support from the National Natural Science Foundation of China(Grant Nos.U23A2060,42177143 and 42277461).
文摘Surrounding rock deterioration and large deformation have always been a significant difficulty in designing and constructing tunnels in soft rock.The key lies in real-time perception and quantitative assessment of the damaged area around the tunnel.An in situ microseismic(MS)monitoring system is established in the plateau soft tock tunnel.This technique facilitates spatiotemporal monitoring of the rock mass's fracturing expansion and squeezing deformation,which agree well with field convergence deformation results.The formation mechanisms of progressive failure evolution of soft rock tunnels were discussed and analyzed with MS data and numerical results.The results demonstrate that:(1)Localized stress concentration and layered rock result in significant asymmetry in micro-fractures propagation in the tunnel radial section.As excavation continues,the fracture extension area extends into the deep surrounding rockmass on the east side affected by the weak bedding;(2)Tunnel excavation and long-term deformation can induce tensile shear action on the rock mass,vertical tension fractures(account for 45%)exist in deep rockmass,which play a crucial role in controlling the macroscopic failure of surrounding rock;and(3)Based on the radiated MS energy,a three-dimensional model was created to visualize the damage zone of the tunnel surrounding rock.The model depicted varying degrees of damage,and three high damage zones were identified.Generally,the depth of high damage zone ranged from 4 m to 12 m.This study may be a valuable reference for the warning and controlling of large deformations in similar projects.
文摘The construction of the new tunnel under the existing railway will break the original stress balance in the engineering area, resulting in the secondary redistribution of surrounding rock stress. The large amount of excavation unloading of the soil below is also easy to induce the uneven settlement deformation of the existing structure above, affecting the safety of driving. Based on the shield tunnel project between Caoqiao Station and Lize Business District Station of Beijing Metro, this paper restores the construction site by constructing the finite element numerical model of the project area, calculates and analyzes the deformation and stress of the existing railway structure before and after the construction of the tunnel, and determines the safety impact of the new structure on the existing railway. The results show that the shield tunnel undercrossing construction will cause the “concave” settlement of the railway subgrade above. Under the condition of grouting reinforcement, the “concave” settlement curve is slower and the distribution range is wider. With the advancement of the construction step, the settlement deformation of the subgrade gradually increases. When the tunnel approaches and passes directly below the subgrade, the settlement deformation curve of the subgrade changes from slow to steep. After the tunnel passes away, the curve changes from steep to slow, and the deformation of the subgrade reaches the maximum after the tunnel is connected. Under the grouting condition, the maximum settlement deformation of the subgrade is 2.08 mm, which is about 45% of the settlement deformation of the subgrade under the non-grouting condition. The ground grouting reinforcement can effectively control the subgrade settlement, and the field monitoring verifies the rationality of the calculation results. After the tunnel passes underneath, the most unfavorable section of the existing railway frame bridge is located at the top plate of the structure, and the maximum crack width is 0.178 mm. After grouting reinforcement, the stress environment of the structure is improved, the crack width generated by the structure is smaller, the reinforcement area required for calculation is less, and the structural safety meets the requirements.
文摘Objective: Stroke is perceived as a serious illness although it is preventable, and lifestyle alterations can be made to reduce its risk. Improvement of stroke care should be achieved through awareness of public, especially through high-risk group. Henceforth, the aim of this study was to evaluate the effect of nursing intervention on improving awareness of high-risk people about stroke prevention. Methods: A quasi-experimental design was used to carry out this study, where a purposive sample of 80 adult patients at high risk for stroke were enrolled while they were attending the out-patient clinics of Zagazig University Hospitals for follow-up treatment;they were divided into two groups: case (40 patients) and control (40 patients). An interview questionnaire was used to assess patients’ knowledge regarding warning signs, risk factors, and immediate treatment;attitude;and their practice for prevention for stroke at pretest and posttest. Results: The study revealed the poor level of knowledge, bad level of preventive behavior, and negative attitude regarding stroke prevention at pre-intervention. However, after intervention, the high-risk people had fair level of knowledge with moderate practice for stroke prevention and positive attitude, with statistically significant difference between pre-post intervention and between the case and control groups. Conclusions: The study revealed that the nursing intervention seemed to change the knowledge, practice, and attitude of subjects regarding stroke prevention. This, in turn, implies that awareness of prevention of stroke and high-risk factor control could be important to reduce the burden of stroke in Egypt. Thus, further research on a larger scale is required to improve population knowledge and behavior for stroke prevention and control.
文摘Objective:To explore the perspectives of high-risk pregnant women regarding the home care program for high-risk pregnancies.Methods:This qualitative study was conducted in a university hospital and 5 comprehensive health centers in Ahvaz,Iran,from February 2023 to July 2023.The sampling method used was purposive sampling considering the maximum possible diversity,which continued until data saturation.11 in-depth and semistructured interviews were conducted with high-risk pregnant women.Data were simultaneously analysed using Graneheim and Lundman content analysis by MAXQDA version 20 software.Results:Data analysis extracted 3 themes,12 categories,and 26 subcategories.The themes and categories were“high-risk pregnancy and related issues(pursuing treatment and paying attention to the high-risk situation by pregnant women,psychological aspect of high-risk pregnancy on pregnant women and caregivers,emotional and physical aspects of high-risk pregnancy,the consequences of high-risk pregnancy on the people around them and empowerment of high-risk pregnant women)”,“support dimension(family and community support for high-risk pregnant women)”,and“framework of program(acculturalization,means and equipment,security,manpower and the necessary arrangements for the home care)”.Conclusions:High-risk pregnancy affects various aspects of the lives of high-risk pregnant women and their families.Creating the necessary conditions for providing care at home plays a vital role in supporting high-risk pregnant women and removing related obstacles to receiving prenatal care in person.It will be especially beneficial for high-risk pregnant women in low-income areas.
基金financially supported by the National Natural Science Foundation of China(Grant No.52078334)the National Key Research and Development Program of China(Grant No.2017YFC0805402)the Tianjin Research Innovation Project for Postgraduate Students(Grant No.2021YJSB141).
文摘The deformation caused by tunnel excavation is quite important for safety,especially when it is adjacent to the existing tunnel.Nevertheless,the investigation of deformation characteristics in overlapped curved shield tunneling remains inadequate.The analytical solution for calculating the deformation of the ground and existing tunnel induced by overlapped curved shield tunneling is derived by the Mirror theory,Mindlin solution and Euler-Bernoulli-Pasternak model,subsequently validated through both finite element simulation and field monitoring.It is determined that the overcutting plays a crucial role in the ground settlement resulting from curved shield tunneling compared to straight shield tunneling.The longitudinal settlement distribution can be categorized into five areas,with the area near the tunnel surface experiencing the most dramatic settlement changes.The deformation of the existing tunnel varies most significantly with turning radius compared to tunnel clearance and grouting pressure,especially when the turning radius is less than 30 times the tunnel diameter.The tunnel crown exhibits larger displacement than the tunnel bottom,resulting in a distinctive‘vertical egg'shape.Furthermore,an optimized overcutting mode is proposed,involving precise control of the extension speed and angular velocity of the overcutting cutter,which effectively mitigates ground deformation,ensuring the protection of the existing tunnel during the construction.
基金Key project in Hubei Province,Grant/Award Number:2023BCB048National Key R&D Program of China,Grant/Award Number:2021YFC3100805+1 种基金National Natural Science Foundation of China,Grant/Award Numbers:42293355,51991392Project for Research Assistant of Chinese Academy of Sciences。
文摘Monitoring of the mechanical behavior of underwater shield tunnels is vital for ensuring their long-term structural stability.Typically determined by empirical or semi-empirical methods,the limited number of monitoring points and coarse monitoring schemes pose huge challenges in terms of capturing the complete mechanical state of the entire structure.Therefore,with the aim of optimizing the monitoring scheme,this study introduces a spatial deduction model for the stress distribution of the overall structure using a machine learning algorithm.Initially,clustering experiments were performed on a numerical data set to determine the typical positions of structural mechanical responses.Subsequently,supervised learning methods were applied to derive the data information across the entire surface by using the data from these typical positions,which allows flexibility in the number and combinations of these points.According to the evaluation results of the model under various conditions,the optimized number of monitoring points and their locations are determined.Experimental findings suggest that an excessive number of monitoring points results in information redundancy,thus diminishing the deduction capability.The primary positions for monitoring points are determined as the spandrel and hance of the tunnel structure,with the arch crown and inch arch serving as additional positions to enhance the monitoring network.Compared with common methods,the proposed model shows significantly improved characterization abilities,establishing its reliability for optimizing the monitoring scheme.
基金Supported by Guiding Project of Hebei Provincial Health Commission,No.20201190 and 20180220.
文摘BACKGROUND Effective health management for high-risk stroke populations is essential.The hospital-community-home(HCH)collaborative health management(CHM)model leverages resources from hospitals,communities,and families.By integrating patient information across these three domains,it facilitates the delivery of tailored guidance,health risk assessments,and three-in-one health education.AIM To explore the effects of the HCH-CHM model on stroke risk reduction in highrisk populations.METHODS In total,110 high-risk stroke patients screened in the community from January 2019 to January 2023 were enrolled,with 52 patients in the control group receiving routine health education and 58 in the observation group receiving HCH-CHM model interventions based on routine health education.Stroke awareness scores,health behavior levels,medication adherence,blood pressure,serum biochemical markers(systolic/diastolic blood pressure,total cholesterol,and triglyceride),and psychological measures(self-rating anxiety/depression scale)were evaluated and compared between groups.RESULTS The observation group showed statistically significant improvements in stroke awareness scores and health behavior levels compared to the control group(P<0.05),with notable enhancements in lifestyle and dietary habits(P<0.05)and reductions in postintervention systolic blood pressure,diastolic blood pressure,total cholesterol,triglyceride,self-rating anxiety scale,and self-rating depression scale scores(P<0.05).CONCLUSION The HCH-CHM model had a significant positive effect on high-risk stroke populations,effectively increasing disease awareness,improving health behavior and medication adherence,and appropriately ameliorating blood pressure,serum biochemical marker levels,and negative psychological symptoms.
基金Supported by Natural Science Foundation of Hubei Province,No.2023AFB848.
文摘BACKGROUND Inadequately controlled hypertension often leads to an increased cardiovascular death rate in type 2 diabetes mellitus(T2DM).It remains unclear whether systolic blood pressure(SBP)status of hypertension is related to coronary inflammation and plaques in T2DM.AIM To evaluate whether SBP variability(SBPV)and levels of hypertension are related to coronary inflammation and plaques in T2DM patients using coronary computed tomography angiography(CCTA).METHODS This retrospective study involved 881 T2DM patients with CCTA images,including 668 hypertension and 213 normotension patients.Hypertension patients were subgroup based on SBP status:(1)SBPV:Low(<8.96 mmHg)and high(≥8.96 mmHg)groups;and(2)SBP levels:Controlled(<140 mmHg)and uncontrolled(≥140 mmHg)groups.Pericoronary adipose tissue(PCAT)attenuation,high-risk plaques(HRPs)and obstructive stenosis(OS)were evaluated by CCTA.Propensity score matching was utilized to compare these CCTA findings for these groups.The impact of SBPV and SBP levels of hypertension on these CCTA findings in T2DM patients were evaluated by multivariate logistic regression and multivariable linear regression.RESULTS PCAT attenuation of the left anterior descending artery(LAD),any low attenuation plaque(LAP),any spotty calcification(SC),any positive remodeling(PR),and OS had significant differences between the hypertension group and the normotension group,as well as between the high SBPV or uncontrolled SBP group and the low SBPV or controlled SBP group(all P<0.05).Hypertension was independently positively correlated with LADPCAT attenuation(β=1.815,P=0.010),LAP(OR=1.612,P=0.019),SC(OR=1.665,P=0.013),PR(OR=1.549,P=0.033),and OS(OR=1.928,P=0.036)in all T2DM patients.Additionally,high SBPV and uncontrolled SBP were independently positively correlated with LAD-PCAT attenuation(high SBPV:β=1.673,P=0.048;uncontrolled SBP:β=2.370,P=0.004)and PR(high SBPV:OR=1.903,P=0.048;uncontrolled SBP:OR=2.230,P=0.013)in T2DM patients with hypertension.CONCLUSION Inadequately controlled hypertension,including high SBPV and/or uncontrolled SBP levels,may be related to increased coronary artery inflammation,HRPs,and OS in T2DM,leading to increased cardiovascular risk.Achieving both low SBPV and controlled SBP levels simultaneously,especially in individuals with T2DM and hypertension,warrants clinical attention.
文摘With recent technological advancements,tunnel boring machines(TBM)have developed and exhibited high performance in large diameters and weak ground conditions.Tunnels are crucial structures that significantly influence the timelines of highway and railway projects.Therefore,the construction of tunnels with TBMs becomes a preferred option.In this study,a comparative analysis between TBM and the New Austrian Tunneling Method(NATM)for tunnel construction is performed in the construction of the T1 tunnel with a diameter of 13 m,which is the longest tunnel in the E?me-Salihli section of Ankara-izmir High-Speed Railway Project(Türkiye).The selection of TBM type,measures taken in problematic sections,and application issues of TBM are discussed.The impact of correct description of geological and geotechnical conditions on both selection and performance of TBM is presented.An earth pressure balanced type TBM is chosen for the construction of the T1 tunnel.Because of the additional engineering measures taken before excavation in problematic areas,the tunnel was completed with great success within the initially planned timeframe.From this point of view,this study is an important case and may contribute to worldwide tunneling literature.
基金supported by the National Natural Science Foundation of China(Grant Nos.52279118 and U21A20159)Sub-project of National Key Research and Development(Grant No.2023YFC3007403).
文摘The seepage of groundwater and the strain-softening of rock mass in a submarine tunnel expand the plastic region of rock,thereby affecting its overall stability.It is therefore essential to study the stress and strain fields in the rocks surrounding the submarine tunnel by considering the coupled effect of strainsoftening and seepage.However,the evolution equation for the hydro-mechanical parameters in the existing fully coupled solution is a uniform equation that is unable to reproduce the characteristics of rock mass in practice.In this study,an updated numerical procedure for the submarine tunnel is derived by coupling strain-softening and seepage effect based on the experimental results.According to the hydro-mechanical coupling theory,the hydro-mechanical parameters such as elastic modulus,Poisson's ratio,Biot's coefficient and permeability coefficient of rocks are characterized by the fitting equations derived from the experimental data.Then,the updated numerical procedure is deduced with the governing equations,boundary conditions,seepage equations and fitting equations.The updated numerical procedure is verified accurately compared with the previous analytical solution.By utilizing the updated numerical procedure,the characteristics of stress field and the influences of initial pore water pressure,Biot's coefficient,and permeability coefficient on the stress,displacement and water-inflow of the surrounding rocks are discussed.Regardless of the variations in hydro-mechanical parameters,the stress distribution has a similar trend.The initial permeability coefficient exerts the most significant influence on the stress field.With the increases in initial pore water pressure and Biot's coefficient,the plastic region expands,and the water-inflow and displacement increase accordingly.Given the fact that the stability of the tunnel is more sensitive to the seepage force controlled by the hydraulic parameters,it is suggested to dewater the ground above the submarine tunnel to control the initial pore water pressure.
基金supported by the National Natural Science Foundation of China(Grant No.12174028)。
文摘In biological neural systems,noise is ubiquitous but does not affect the correct decisions made in the complex cognitive tasks.Decision-making in biological neural system is typically achieved by accumulating input information over a period of time.Inspired by recent developments in neurosciences,we design a decision-making module based on spintronic devices,utilizing superparamagnetic tunnel junctions as artificial neurons.The feasibility of this decision-making module is verified through circuit simulations.Taking a multi-layer perceptron as an example,the module significantly improves the accuracy of the perceptron in the handwritten digit recognition task.Furthermore,the spintronic decision-making module offers advantages over the conventional pooling methods,such as adaptive decision time,high performance and the absence of analog-to-digital conversion.The decision-making module is flexible to be integrated into artificial neural networks and provides a general yet effective solution to enhance performance against device noise.
基金National Natural Science Foundation of China,Grant/Award Numbers:41977218,42222707State Key Laboratory for GeoMechanics and Deep Underground Engineering,Grant/Award Number:SKLGDUEK2117。
文摘Shield tunnel,composed of several segments,is widely used in urban underground engineering.When the tunnel is under load,relative displacement occurs between adjacent segments.In the past,distributed optical fiber sensing technology was used to perform strain monitoring,but there is an urgent need to determine how to transform strain into displacement.In this study,optical frequency domain reflectometry was applied in laboratory tests.Aiming at the shear process and center settlement process of shield tunnel segments,two kinds of quantitative calculation methods were put forward to carry out a quantitative analysis.Meanwhile,the laboratory test process was simulated numerically utilizing the discrete element numerical analysis method.Optical fiber,an atypical geotechnical material,was innovatively applied for discrete element modeling and numerical simulation.The results show that the measured displacement of the dial gauge,the calculated results of the numerical model,and the displacement quantitatively calculated from the optical fiber data agree with each other in general.The latter two methods can potentially be utilized in engineering application of deformation monitoring at shield tunnel joints,but need to be further calibrated and adjusted in detail.
基金Project supported by the National Key Research&Development Program of China(Grant Nos.2019YFA0308600 and 2020YFA0309000)the National Natural Science Foundation of China(Grant Nos.92365302,92065201,22325203,92265105,12074247,12174252,52102336)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)the Science and Technology Commission of Shanghai Municipality(Grant Nos.2019SHZDZX01,19JC1412701,20QA1405100,24LZ1401000,LZPY2024-04)financial support from the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302500)。
文摘Manipulating and braiding Majorana zero modes(MZM)are a critical step toward realizing topological quantum computing.The primary challenge is controlling the vortex,which hosts the MZM,within a superconducting film in a spatially precise manner.To address this,we developed a magnetic force-based vortex control technology using the STM system with a self-designed four-electrode piezo-scanner tube and investigated vortex manipulation on the NbSe_(2) superconducting film.We employed ferromagnetic tips to control the movement of vortex array induced by the tip's remanent magnetism.A magnetic core solenoid device was integrated into the STM system and a strong magnetic tip demagnetization technique was developed,providing a viable technical solution for further enabling single vortex manipulation.
基金National Natural Science Foundation of China(41630640)National Science Foundation of Innovation Research Group(41521002)+1 种基金National Natural Science Foundation of China(41790445)Construction S&T Project of Department of Transportation of Sichuan Province(Grant No.2020A01).
文摘The stratum lithology and geological structure of the highway tunnel in the mountainous areas of western China are complex,and the engineering geological conditions are complicated.When the highway tunnel passes through different lithological strata,its structural design and construction technology are completely diff erent.Therefore,in order to support the tunnel design and construction,the tunnel survey Among them,the identifi cation of the contact boundary between magmatic rock and metamorphic rock and the grade of surrounding rock is very important.Through magnetotelluric survey of the Mupi tunnel of Jiuzhaigou-Mianyang highway on G8513 line,2D forward numerical simulation,1D,2D,3D inversion,and engineering geological analysis,it is revealed that the electrical characteristics of each layer,focusing on the identifi cation of the contact boundary between magmatic rock and metamorphic rock.This study provides the electrical characteristics of the magmatic rock and metamorphic rock contact boundary of the Mupi Tunnel.It is speculated that the boundary is revealed by the tunnel construction excavation,which verifies the correctness of the geophysical inversion model and provides a more detailed design basis for the tunnel design.I believe that taking the Mupi Tunnel survey as an example,through this research,it can provide detailed geophysical evidence for highway tunnels to distinguish between magmatic rock and metamorphic rock.
基金supported by the National Key Research&Development Program of China(Grant No.2023YFC3008404)the Key Laboratory of Earth Fissures Geological Disaster,Ministry of Natural Resources,China(Grant Nos.EFGD20240609 and EFGD20240610).
文摘The recent upsurge in metro construction emphasizes the necessity of understanding the mechanical performance of metro shield tunnel subjected to the influence of ground fissures.In this study,a largescale experiment,in combination with numerical simulation,was conducted to investigate the influence of ground fissures on a metro shield tunnel.The results indicate that the lining contact pressure at the vault increases in the hanging wall while decreases in the footwall,resulting in a two-dimensional stress state of vertical shear and axial tension-compression,and simultaneous vertical dislocation and axial tilt for the segments around the ground fissure.In addition,the damage to curved bolts includes tensile yield,flexural yield,and shear twist,leading to obvious concrete lining damage,particularly at the vault,arch bottom,and hance,indicating that the joints in these positions are weak areas.The shield tunnel orthogonal to the ground fissure ultimately experiences shear failure,suggesting that the maximum actual dislocation of ground fissure that the structure can withstand is approximately 20 cm,and five segment rings in the hanging wall and six segment rings in the footwall also need to be reinforced.This study could provide a reference for metro design in ground fissure sites.
基金Project supported by the National Natural Science Foundation of China(Nos.11972203 and 11572162)the Science and Technology Innovation 2025 Major Project of Ningbo City of China(No.2022Z209)Ningbo Key Technology Breakthrough Plan Project of“Science and Technology Innovation Yongjiang 2035”(No.2024Z256)。
文摘Carbon nanotubes(CNTs)have garnered great attention in recent years due to their outstanding electrical,thermal,and mechanical properties.The incorporation of small amounts of CNTs in polymers can substantially improve the sensitivity of the polymer's electrical conductivity.This paper presents a modified Maxwell model to evaluate the electrical conductivity of CNTs-filled polymer composites by introducing a transition zone to account for the tunneling effect.In this modified Maxwell model,the CNTs-filled polymer composite is modeled as a three-phase composite,consisting of a matrix(polymer),inclusions(CNTs),and a transition zone(tunneling zone).The effective electrical conductivity(EEC)of the composite is calculated based on the volume fractions and electrical conductivities of the matrix,inclusions,and transition zone.The model's validity is confirmed through the use of available test data,which demonstrates its capability to accurately capture the nonlinear conductivity behavior observed in CNTs-polymer composites.This study offers valuable insights into the design of high-performance conductive polymer nanocomposites,and enhances the understanding of electrical conduction mechanisms in CNT-dispersed polymer composites.
文摘Objective:To evaluate the impact of subcutaneous tunneling on peripherally inserted central catheters(PICCs)dislodgement and malposition.Dislodged or malpositioned PICCs can lead to improper treatment.The subcutaneous tunneling strategy may be effective,but there is insufficient evidence,and proximal movement has not been explored.Methods:We randomized 630 patients who needed PICCs placement to either the tunneled PICCs(experimental group)or the non-tunneled PICCs(control group).Dislodgement and malposition of the catheter were the primary outcomes,and catheter-related infection(CRI)and catheter-related thrombosis(CRT)were the secondary outcomes.Results:Subcutaneous tunneling does not significantly reduce distal catheter movement,but it significantly reduces proximal catheter movement(4.3%vs.9.9%,P=0.007),which may explain the lower incidence of CRI(2.0%vs.5.3%,P=0.030)and CRT(3.6%vs.12.5%,P<0.001).Conclusions:Although subcutaneous tunneling does not significantly improve catheter prolapse,it should still be used clinically because proximal catheter movement can be a more serious problem associated with CRI and CRT.
文摘Background:Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality. While liver transplantation (LT) provides the best long-term survival, it is constrained by organ scarcity and strict criteria. Liver resection (LR) is often the initial treatment for patients with solitary tumors and preserved liver function. The high recurrence rates associated with LR has prompted the exploration of sequential living donor liver transplantation (seq LDLT) after LR as a strategy for HCC patients with high-risk of recurrence.Methods:We analyzed data from 27 adult patients who underwent seq LDLT after LR for HCC at Kaohsiung Chang Gung Memorial Hospital (KCGMH) between June 1994 and December 2023. Patients were selected based on high-risk histopathological features post-LR or as part of downstaging strategy. Outcomes measured included overall survival (OS) and disease-free survival (DFS).Results:Among 765 HCC patients who underwent LDLT, 204 received LR before LDLT, and 27 underwent seqL DLT. Five patients (19%) underwent living donor liver transplantation (LDLT) following LR as a downstaging strategy while the rest received seqL DLT as a preemptive strategy. The median age was 53.5 years with 85%males. Chronic hepatitis B was the predominant underlying disease (74%). The 1-, 3-, and 5-year OS and DFS rates were 100%, 96.0%, 96.0%and 100%, 96.2%, 96.2%, respectively, with two patients experiencing HCC recurrence. One patient died from HCC recurrence. High-risk histopathological features included microvascular invasion (52%), satellite nodules (15%), multiple tumors (26%), tumors> 5 cm(19%), and a total tumor diameter> 10 cm (7%).Conclusions:Seq LDLT offers a promising, tailored approach for managing HCC with adverse histopathologic features. Combining seq LDLT, downstaging strategies, and multidisciplinary treatments can achieve satisfactory OS and DFS in carefully selected patients, highlighting the need for refined criteria to identify the best candidates.
基金funded by the National Natural Science Foundation of China(Grant No.42377195)。
文摘A fault is a geological structure characterized by significant displacement of rock masses along a fault plane within the Earth's crust.The Yunnan Tabaiyi Tunnel intersects multiple fault zones,making tunnel construction in fault-prone areas particularly vulnerable to the effects of fault activity due to the complexities of the surrounding geological environment.To investigate the dynamic response characteristics of tunnel structures under varying surrounding rock conditions,a three-dimensional large-scale shaking table physical model test was conducted.This study also aimed to explore the damage mechanisms associated with the Tabaiyi Tunnel under seismic loading.The results demonstrate that poor quality surrounding rock enhances the seismic response of the tunnel.This effect is primarily attributed to the distribution characteristics of acceleration,dynamic strain,and dynamic soil pressure.A comparison between unidirectional and multi-directional(including vertical)seismic motions reveals that vertical seismic motion has a more significant impact on specific tunnel locations.Specifically,the maximum tensile stress is observed at the arch shoulder,with values ranging from 60 to 100 k Pa.Moreover,NPR(Non-Prestressed Reinforced)anchor cables exhibit a substantial constant resistance effect under low-amplitude seismic waves.However,when the input earthquake amplitude reaches 0.8g,local sliding occurs at the arch shoulder region of the NPR anchor cable.These findings underscore the importance of focusing on seismic mitigation measures in fault zones and reinforcing critical areas,such as the arch shoulders,in practical engineering applications.
