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This study centers on the use of smart technology to improve the lifecycle management of underground facilities. It presents a comprehensive digital solution that addresses the challenges of underground facilities, particularly those related to the extensive use of underground space, as well as the requirements for safety, sustainability, and quality of services. The proposed solution emerged from discussions with experts, companies, and cities involved in the design, construction, and management of underground facilities. In this paper, we first discuss the major challenges of underground facilities, then, we present the development of a smart solution to address these challenges. This study demonstrates a promising perspective for the use of smart technology in the optimal management of underground facilities, and paves the way for its implementation.

In recent years, carbon films have attracted interest as electrode materials for electrochemical sensors due to their wide potential window and acceptable electrochemical activity. The films can be fabricated into electrodes of any shape and size. The electrochemical performance of the films depends on their structural features such as the ratio of the sp2 and sp3 bonds, and the surface functional groups. Here, we report the control of both structure and electrochemical properties based on carbon films fabricated by easily available direct current (DC) magnetron sputtering equipment. The sp3 concentration (sp3/sp3 + sp2) can be controlled from 0.22 to 0.29 by changing the substrate bias power, which can be characterized with X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The potential window became wider as the sp3 concentration increased, similar to the results we previously obtained with films formed by unbalanced magnetron (UBM) sputtering. The electrochemical properties of DC magnetron sputtered carbon films were examined with four species, namely Ru(NH3)62+/3+, Fe(CN)63−/4−, Fe2+/3+, and dopamine. The peak separation of these species depended on the content of the edge plane of the film for Fe(CN)63−/4− and surface functional groups containing oxygen for Fe2+/3+, and both edge plane and surface oxygen-containing groups for dopamine. These results indicate that our carbon films perform sufficiently well for use in electroanalysis and are not inferior to previously reported carbon film electrodes.

We examine whether Chinese firms with better voluntary corporate social responsibility (CSR) disclosure and CSR performance engage in earnings management in their financial reporting. Our results show that Chinese firms with better voluntary CSR disclosure are more likely to engage in earnings management through discretionary accruals and less likely to engage in earnings management through real activities manipulation, while Chinese firms with better CSR performance are more likely to engage in earnings management through real activities manipulation and are less likely to engage in earnings management through discretionary accruals. Our evidence shows that consistent with opportunistic theory, the Chinese firms’ engagement in CSR practices is based on opportunistic incentives, and voluntary CSR disclosure and CSR performance are being used by these firms as window-dressing tools for earnings management that infringes on the benefits of firm stakeholders.

PurposeEmbracing big data has been at the forefront of research for project management. Although there is a consensus that the adoption of big data has significantly positive impact on project performance, far less is known about how this innovative information technology becomes an effective driver of construction project quality improvement. This study aims to better understand the mechanism and conditions under which big data can effectively improve project quality performance.Design/methodology/approachAdopting Chinese construction enterprises as samples, the theoretical framework proposed in this paper is verified by the empirical results of the two-level hierarchical linear model. The moderated mediation analysis is also conducted to test the hypotheses. Finally, the empirical findings are validated by a comparative case study.FindingsThe results show that big data facilitates the development of technology capability, which further produces remarkable quality performance. That is, a project team's technology capability acts as a mediator in the relationship between organizational adaptability of big data and predictive analytics and project quality performance. It is also observed that two types of project team interdependence (goal and task interdependence) positively moderate the mediation effect.Research limitations/implicationsThe questionnaire study from China only represents the relationship within a short time interval in the current context. Future studies should apply longitudinal designs to properly test the causality and use multiple data sources to ensure the validity and robustness of the conclusions.Practical implicationsThe value of big data in terms of quality improvement could not be determined in a vacuum; it also depends on the internal capability development and elaborate design of project governance.Originality/valueThis study provides an extension of the existing big data studies and fuels the ongoing debate on its actual outcomes in project management. It not only clarifies the direct effect of big data on project quality improvement but also identifies the mechanism and conditions under which the adoption of big data can play an effective role.

Purpose To demonstrate a specific skin dose limiting technique in radiotherapy treatment planning for esophageal cancer and carry out a comparative analysis combining with clinical cases. Material and methods Thirty patients with cervical and upper thoracic esophageal carcinoma previously treated in our institution were selected. A treatment plan had been finished previously according to the planning parameters directives from physician and delivered for each patient. In this study, we copied the previously delivered plans in radiotherapy treatment planning system and converted a low dose level (usually 5Gy) to a skin dose limiting structure (SDLS), then we set the objective functions of the SDLS in the Pinnacle Inverse Planning module and re‐optimize the plans to reduce the skin doses. Finally, we compared the dose distribution and other parameters of target volume and organs at risk (OARs) between the old plans and the new plans. Results There was no significant difference in most of OARs sparing. However, for all plans, the maximum dose to the SDLS decreased from 6145.90 ± 416.96 cGy to 5562.09 ± 616.69 cGy with maximum difference of 1361.30 cGy (P

Block theory has been widely used in analyzing the stability of rock blocks during engineering activities in jointed rock masses due to its simplicity and computational efficiency. This paper extended the traditional block theory to tunnels constructed using tunnel boring machine (TBM) by incorporating the disc cutter-block interaction mechanism. The rock blocks were divided into front, corner and rear blocks according to their spatial positions with respect to the cutterhead. The interaction between different blocks and the disc cutters mounted on the cutterhead were examined by estimating the forces exerted by disc cutters on the blocks relative to the location of the blocks in the face, direction of movement of the discs, and the depth of penetration. The estimated forces were then used in a subsequent analysis to calculate factor of safety for individual blocks and probability of blocks dislodging from its location. Two new evaluation parameters, e A and e η , were proposed to account for the probability of block instability. e A is the ratio of exposed area of unstable blocks to the face area and quantifies the size of unstable blocks relative to the face, and e η is the ratio of cutterhead rotation angles making a block unstable to the total rotation angles in a revolution which reflects the possibility of encountering an unstable block during a single round of revolution. This paper discussed the implementation of the idea of using fundamental concepts of block theory to determine block stability at the face and related analysis for assessment of face stability. The proposed method was used in evaluation of the stability conditions for a water-conveyance tunnel in western China that is currently under construction using a hard rock TBM.

This paper investigated the three-dimensional effect through full-scale loading tests on both a single (isolated) full-ring structure and a staggered-fabricated three-ring structure for a water storage and sewage tunnel. Some observations common for both the single-ring and three-ring tests were identified: both the internal forces and deformation of the testing specimen increase as the burial depth increases; whereas, the axial force decreases but the deformation of the testing specimen increases with increasing inner water head. Comparing with the single-ring tests, the deformation of longitudinal joints and the convergence deformation of the testing specimen are significantly reduced in the three-ring tests. The reasons may be two-fold: firstly, the staggered fabrication causes the redistribution of bending moment in the longitudinal direction, which transfers a certain amount of bending moment from the longitudinal joints to the segment body of adjacent rings; secondly, the presence of thrust force leads to the closure of circumferential joints, which co-acting with the longitudinal bolts, enforces the joints to deform together with the segment body of adjacent rings and thus restricts the deformation of the longitudinal joints. It is also shown that the mechanism of bending moment transmission is not unique but depends on the loading conditions and joint locations.

The slurry infiltration process plays a crucial role in the slurry shield tunneling process, during which a filter cake is expected to form on the tunnel face to transmit the support pressure. This paper proposed a coupled computational fluid dynamics (CFD)-discrete element method (DEM) numerical approach to investigate the slurry infiltration and filter cake formation by modeling the slurry filtration column test, which incorporates the particles, fluid phase, and their interactions. The Simplified Johnson-Kendall-Roberts (SJKR) model was employed to consider the cohesion effect between slurry particles. The validity of the current approach was verified based on the Kozeny-Carman Equation modified by Ergun (1952) . The slurry filtration process was divided into four stages with different characteristics of filter cake porosity and pressure drop. Influences of some key model parameters including externally-applied pressure, friction coefficient and cohesion energy density on filter cake formation were investigated and the underlying mechanisms were explored. The law of pressure variation within the filter cake was proposed. A linear relationship between pressure drop ratio and porosity of filter cake was established, which will be useful for predicting the effectiveness of support pressure transmission due to slurry filtration.

A novel testing setup is developed for structural tests on segmental joints of shield tunnels. It lies on the ground and is a self-balanced system. The applied axial force and bending moment are coupled, and the combination of target axial force and bending moment at the joint can be achieved by adjusting the horizontally-applied forces. It is more economic and flexible than the traditional two-point bending testing setups. The effectiveness of internal force/moment transmission of the testing setup was verified by comparing the experimental data with theoretically-determined values and numerical simulation results. It was then applied to investigate the flexural behaviour of longitudinal joint of a deeply-buried tunnel subjected to both sagging and hogging moments. The rotational stiffnesses of the testing joint were determined. The influences of bending moment and axial force on joint deformation were unified through eccentricity. In both the sagging moment and hogging moment cases, the joint deformation varied with eccentricity following a bilinear trend composed of an axial-force-dominant stage and a bending-moment-dominant stage. The slopes of the relationships between eccentricity and joint rotation angle are steeper in the hogging moment case than in the sagging moment case due to the absence of bolts at the extrados.

Due to the presence of varying inner water head, the mechanical behavior of water storage and sewage tunnel is different from normal transportation tunnels. This paper investigated the three-dimensional response of a staggeredly fabricated water storage and sewage tunnel through sophisticated 3D finite element (FE) modeling, in which detailed configuration of the segmental joints and interactions between different connecting components were reproduced. The FE model and input parameters were validated against precedent full-scale loading testing data under both normal operational and cyclic loading paths considering the periodic variation of inner water head. The characteristics of internal force transmission between longitudinal joints and adjacent segments in the longitudinal direction was investigated, and its spatial variability and loading path dependency were discussed. It is found that this self-adaptive internal force transmission mechanism yields a more compatible loading bearing mode, which is beneficial for deformation control. The influences of some important factors on the three-dimensional response of the lining structure were investigated, including the largest inner water head in loading history, distributions of the longitudinal joints and magnitude of longitudinal thrust force, based on which recommendations for practical design and construction were provided.

Capturing the cracking process during prototype loading tests of segmental lining is crucial for the design of tunnel structures. This paper presents an application case history of 3D digital image...

The operation of cascaded reservoirs is a complex problem, and lots of algorithms have been developed for optimal cascaded reservoir operation. However, the existing algorithms usually have disadvantages such as the ‘curse of dimensionality’ and prematurity. This study proposes a grey discrete differential dynamic programming (GDDDP) algorithm for effectively optimizing the cascaded reservoir operation model, which is a combination of the grey forecasting model and discrete differential dynamic programming (DDDP). Additionally, a modification of the grey forecasting model is presented for better forecast accuracy. The proposed method is applied to optimize the Baishan-Fengman cascaded reservoir system in the northeast of China. The results show that GDDDP obtains more power generation than DDDP with less computing time in three cases, i.e., dry years, wet years and the whole series. Especially in the case of the whole series, the power generation of GDDDP is 2.13 MWH more than that of DDDP, while the computing time is decreased by 66,161 ms. Moreover, the power generation of GDDDP is comparable with that of dynamic programming but the computing time is much less. All these indicate GDDDP has high accuracy and efficiency, which implies that it is practicable for the operation of a cascaded reservoir system.

Integrated curriculum are essential to cultivate students' innovative spirit, social responsibility, core competencies, and global vision. However, its significant challenges are educational resource shortages and teacher inexperience. The rapid development of current technology has brought new solutions but existing educational platforms or communities are mainly test-oriented, and teaching resources are outdated and isolated. There is no specific solution to the problem of integrated curriculum mentioned above. This paper proposes design principles of the platform and resource sharing mechanism of the "discovery-design-share" cycle through a user behavior analysis of an informal WeChat community. Based on the resource sharing mechanism, this paper designs the platform architecture and specific functional modules, including the resource library, curriculum design tools, cloud workspace, and teacher community, and provides mobile access. Therefore, teachers can find sustainable, suitable and real-world resources on the platform, and improve their capabilities through designing and sharing integrated curriculum on the platform.

Aims Guidelines divide patients with heart failure (HF) into 3 distinct groups based on left ventricular ejection fraction (LVEF) We used the Minnesota Living with Heart Failure Questionnaire (MLHFQ) to quantify the health-related quality of life in patients with HF. Methods Patients were stratified into three cohorts: preserved LVEF (>50%), mid-range LVEF (40–49%) and reduced LVEF (

Constructing deeply-buried stormwater sewage and storage tunnels is an effective method to mitigate the waterlogging and sewer overflow problems in modern cities. Prior to construction of such tunnels, a structural loading test is essential for acquiring the mechanical responses under complex loading conditions, such as cyclic inner hydraulic head, during which capturing the full-ring deformation of the tunnel lining is significant for a comprehensive understanding of the tunnel&rsquo, s mechanical behaviors. This paper introduces the application of terrestrial laser scanning (TLS) technology in the full-scale structural loading tests of a large stormwater sewage and storage tunnel, which gives the full-ring deformation throughout the tests. A data processing methodology was developed to extract the key data points of the lining segments from the original data cloud by removing noise points and mitigating data jump, based on which the deformation of testing the lining segments at arbitrary locations can be calculated. Furthermore, a post-processing software was developed to visualize the full-ring deformation. The full-ring deformation at different loading conditions and its evolution under cyclic loading were captured. It is shown that the lining&rsquo, s convergence deformation is more sensitive to the inner hydraulic head than to the external soil-water pressure, and the deformation cannot fully recover in a water-inflow-and-drainage cycle due to the presence of joints.

The existing photoacoustic/ultrasound (PA/US) endoscopes with compromise in lateral resolution were difficult to realize superior anatomical imaging. To obtain comprehensive biological information of the colorectum in a noninvasive manner, a tens-of-micron-resolved PA/US endoscope with a 360° field of view was developed. A coaxial structure, which ensures optical and acoustic foci aligned, was employed, and a PVDF-based focused transducer with a high frequency was applied. The endoscopic system achieved lateral resolutions of 16 μm (PA) and 73 μm (US), and axial resolution of 65 μm. Phantom and ex vivo experiments were performed to estimate the performance of the dual-modality endoscope. In vivo three-dimensional imaging of rabbit colorectum exhibited the intact vascular network at different depths from the mucosa of the colorectal wall to the mesentery, and the structures beneath them. Therefore, in vivo anatomical imaging demonstrates that the tens-of-micron-resolved PA/US endoscope holds great potential in the clinical detection of colorectal diseases.

Currently, the reported endoscopic system cannot meet the necessary conditions for real-time and optical-resolution clinical application simultaneously. In this study, by utilizing a high-repetition-rate laser and optimizing the overall structure of the probe, a real-time optical-resolution photoacoustic endoscope was developed, which could image targets in real time while maintaining a relatively constant lateral resolution. The endoscopic system has a best-resolution of 19 μm and a real-time imaging speed of 25 Hz. Experimental results demonstrate that this approach will push the promotion and commercialization of photoacoustic endoscopic imaging in a variety of preclinical and clinical applications.

Circular tunnels are usually encountered when excavating in weak soil medium at shallow depth and using shield machines. However, special shaped tunnels such as squared tunnels and sub-rectangular tunnels are also recently used to improve the efficiency of underground space use. This paper focuses on improving the performance of the Hyperstatic Reaction Method (HRM), which is a numerical method, for the case of squared or sub-rectangular tunnels. Special attention is paid to the tunnel shape influence by using various tunnel wall radii. The numerical HRM model was validated based on a comparison with the finite element method (FEM). The results indicated that HRM can be effectively used to estimate the behavior of squared or sub-rectangular tunnels. Then a parametric study was conducted to highlight the influence of the earth pressure coefficient and of the soil Young’s modulus on the structural forces, and deformations induced by the excavation in the tunnel lining.

The morphological visualization method is improved by introducing the separating axes method to the element-block aggregation algorithm and the weighted quick-union method to the complex-block construction algorithm to enhance the computational efficiency of BLKLAB (Zhang and Lei, 2013a). The usage and effectiveness of the modified BLKLAB code are demonstrated through a case study of Xiang'an tunnel in Xiamen City of China. In this case study, the DifFUZZY method was employed to cluster the orientation data and probabilistic analysis was then performed to get a combination of geological and mechanical properties of discontinuities that is most detrimental to the stability of rock blocks and associated ground-supports. Based on these previous analyses, the fracture network was constructed. The stability of rock blocks around the tunnel was then evaluated, using the improved morphological visualization method in conjunction with the stereo-analytical method. A combination of shot concrete and bolts was proposed as the optimal support system, which agrees with the real situation.

A shell-spring finite element model of a special-shaped tunnel was established to investigate the distribution of internal forces and deformation mode of the lining at the designed buried depth. The numerical results were compared with prototype loading test results and uniform beam model, which showed that the shell-spring model can be an optimal model to calibrate the 3D distribution of the internal forces and deformations of the special-shaped tunnel. Finally, the internal forces in the design condition were given. Furthermore, the economy and mechanical property of a special-shaped tunnel were compared with circular and rectangular tunnels with the same dimension and joint parameters. Results showed that the proposed special-shaped tunnel was more suitable for shallow overburden ground.

When designing a shield tunnel, there is often a need to carry out mechanical tests on tunnel lining joints to obtain joint stiffness. As tunnel excavation goes deeper, the moment and axial force acting on the lining segments increase, which requires a more rigid backup frame and a stronger foundation for the traditional testing setup. A new testing setup, named as Compression Steel Butterfly (CSB), was developed. CSB is biaxially symmetric in geometry, consisting of two steel frames connected by horizontal tensile pulling rods passing through the mounting holes of hollow hydraulic ram jacks. Using CSB, different combinations of axial force and bending moment can be effectively and conveniently imposed on the testing segments by varying the magnitudes of pulling force of each pair of pulling rods. Since the jacking forces are self-balanced, there is no need for a strong backup frame. A series of finite element simulations were carried out to validate the loading capacity and correctness of load transmission for the new testing setup. It is shown that the axial force and moment obtained in numerical simulations agree well with the theoretical values.

Interaction between TBM and the surrounding rock masses is consist of the cutterhead-block interaction and shield-block interaction, leading to the stability consideration of TBM tunnels. The equilibrium equation of removable blocks is derived by taking into consideration of the interaction forces and the net sliding forces of moving modes is also deduced. For different types of blocks in terms of the new classification of blocks in TBM tunnels, sliding and falling will happen for rear blocks, while front blocks and corner blocks will only experience sliding motion.

A new block-classification method for tunnel construction using a tunnel-boring machine (TBM) to capture the geometrical and mechanical transformation of rock blocks in the course of TBM excavation is proposed in this paper. The machine–block interaction is interpreted by dividing the joint blocks into blocks influenced by TBM excavation and blocks uninfluenced by TBM excavation. The influenced blocks are categorized further as contacting or noncontacting blocks according to whether they are in contact with the TBM. The contacting blocks include the front block, the corner block, and the rear block, based on the spatial location of blocks with respect to the cutterhead. Different types of blocks have distinct kinematic and mechanical characteristics. The sizes and shapes evolve, and the categories may be changed for rock blocks during excavation. The identification algorithms for influenced blocks and three types of contacting blocks are presented. Finally, a simple example considering a double-shield TBM tunnel excavation is used to illustrate the effectiveness of the new block-classification approach to guide TBM tunneling. The new classification approach will be helpful in evaluating the block removability and the possibility of cutterhead clogging and to shield blockage during tunneling with a TBM.

The study investigates the disturbance to piles and pile groups caused by multiple nearby drives of a large diameter slurry shield-driven tunnelling machine in Shanghai. The minimum distance between the slurry shield tunnel (with diameter D = 15.43 m) and the adjacent pile groups of Metro Line 3 and Yixian Elevated Road is 1 m. The nonlinear finite element (FE) software program ABAQUS was used to analyse the movement of the pile groups caused by the process of shield tunnelling. A field investigation was conducted before the multiple crossings to study the impact (movement and excess pore water pressure) on the surrounding soil and piles caused by the tunnelling process. The field investigation is divided into two sections: (i) free-field tunnelling, and (ii) tunnelling close to trial piles pre-installed in the section. For the full-scale test, tunnelling variable, including slurry pressure and grouting pressure, are adjusted during construction to reduce the disturbance during tunnelling close to pile groups supporting two elevated bridges. The FE simulation of the multiple crossings includes two steps: (a) shield tunnelling along the south bound tunnel approaching the working shaft at the western bank of the Huangpu River, and passing separately between two adjacent pile groups of each bridge; (b) return tunnel passing again between the pile groups of the two bridges along the north bound tunnel. Three different FE models are generated: (1) free-field tunnelling process, (2) tunnelling close to trial piles, and (3) multiple tunnel passes adjacent to pile groups supporting the two elevated bridges. Most of the relevant factors in tunnelling are taken into consideration in the FE models including (a) slurry pressure, (b) grouting pressure, (c) grouting material hardening, and (d) soil-pile interaction.

A series of prototype structural loading tests were performed in this paper to explore the mechanical behavior of a large special-shaped shield tunnel lining towards failure. To replicate the real working conditions, the testing specimen was fabricated and tested in a ‘standing’ state. It was shown that, similar to circular tunnels, the internal forces and overall deformation of the special-shaped lining structure increased with increasing burial depth. However, the maximum negative bending moments of the special-shaped lining structure were present at the shoulder areas rather than at the waist areas. The two key design parameters, effective transverse rigidity ratio and rotational stiffness, were shown to evolve during loading. A unique relationship between the joint rotational stiffness and eccentricity was obtained, which could be divided into an axial force-dominating phase and a bending moment-dominating phase. Different cracks appeared at different loading stages and the crack width also evolved as loading proceeded. Empirical correlations between various structural properties and cracking characteristics were established, based on which the progressive failure process was elucidated. It was found that due to the transferring of bending moment, cracks were mostly concentrated on segmental bodies in the ring(s) adjacent to the longitudinal joints.

This paper presents an object-oriented computer model for three-dimensional multi-block systems based on the object-oriented programming (OOP) technique. The intricate structures of rock systems are deciphered by implementing an object-oriented analysis (OOA), and a universal class library is developed using an object-oriented design (OOD). The geometries of a multi-block system are created by cutting a computational domain into element-blocks and then combining the element-blocks into complex-blocks (convex or concave). The established multi-block system model would be available for various discontinuum-based methods. A computer program, BLKLAB, is developed based on the proposed method, and a case study is performed on a large-scale, underground, water-tight oil depot.

Objective: The aim of this study was to assess the relationship of blood pressure variability (BPV) and heart rate variability (HRV) to investigate the effect of baroreflex function on blood pressure variability. Methods: This study consisted of 111 subjects, including 32 normotensives and 79 hypertensives. All the subjects were given two concurrent tests: 24-hour Holter ECG and ambulatory blood pressure monitoring. According to standard deviation of normal-to-normal sinus RR intervals (SDNN) derived from the Holter ECG, the hypertensives were divided into two groups: an HRV normal group with SDNN > 100 ms and an HRV abnormal group with SDNN

Objective Cardiac rehabilitation (CR) improves patient outcomes in cardiovascular disease (CVD), but little is known about its current practice in China. Since China has a high CVD burden, the potential impact of CR is large. We surveyed large hospitals in China to assess the prevalence and characteristics of CR. Methods We carried out a cross-sectional survey of 454 large medical centres in China to ascertain the prevalence of CR, perceived barriers to CR and various other characteristics of centres with and without CR programmes. Results Responses were received from 124 (27%) of the 454 centres surveyed. Of these, only 30 (24%) reported having an operating CR programme. This was true, despite the near universal availability of advanced imaging, coronary stenting and other technologies. Overall, the estimated availability of CR programmes was about 2 programmes per 100 million inhabitants. Centres with CR were more likely than centres without CR to be university or government hospitals, have more inpatient cardiovascular beds and provide secondary CVD prevention services. Perceived barriers to CR included a lack of awareness, training and experience in CR, as well as limited resources for a CR programme. Respondents suggested that educational and training activities could help promote greater implementation of CR in China. Conclusions The availability of CR is low (24%) in the large medical centres in China we surveyed, highlighting the importance of efforts to raise awareness of the benefits of CR, to provide CR training to healthcare professionals and to improve CR availability throughout China.

This paper presents a smart monitoring system for risk management in the underground space. This space has a major role in cities, but it suffers from high vulnerability to hazards such as fire, flood and accidents. The paper provides analysis of the vulnerability of the underground space and shows how a smart monitoring system of human presence, indoor conditions, underground space access and equipment performances with advanced data analysis could help in improving the risk management in this space.

In this paper, a numerical simulation method for evaluating tunnelling-induced ground movement is presented. The method involves discrete element simulation of TBM slurry shield advancement and considers explicitly soil excavation from the face, effects of varying face support pressure, and the influence of tunnel cover depth. For the cases studied, it is found that for tunnel cover depths (C/D) between 0.7 and 2.1, ground deformations inducing by the tunnelling can be controlled within a certain extent and tunnel face stability can ensured, provided the support pressure ratio (N) lies between 0.8 and 1.5. The proposed method is reasonably benefited to modeling the face stability in shield-driven tunnels in soft soils.

This paper presents a new conception—ecological tunnel, which is contrived to meet increasingly tough challenges in the 21st century. Ecological tunnel refers to integrating ecological principles into tunnel design, construction and operation in order to create a balanced and sustainable tunnel-nature system. It consists of four elements: green tunneling, green lighting, green lining, and green recycling of excavated material. The conception, function and implementation of each part are elaborated in the paper. In addition, computer visualization technique is applied to simulate complicated internal conditions of an ecological tunnel.

Tunneling in highly permeable ground using a slurry shield machine can be challenging because it is difficult to form the so-called filter cake on the tunnel face to transport the support pressure. Consequently, destructive accidents might happen, such as face instability and water inrush. How to form an efficient filter cake in time is crucial during engineering practice, especially in ground with high permeability. Various theoretical and experimental analyses regarding the formation of filter cakes have been conducted. However, due to the complexity of this problem, which has to incorporate the mechanical and hydraulic behaviors of the fluid&ndash, solid mixture system, few numerical simulations are found in the literature. In this paper, with the aid of a newly developed numerical tool, a coupled CFD (computational fluid dynamics)&ndash, DEM (discrete element method) simulation is established to study the slurry infiltration and filter cake formation during slurry shield tunneling. The slurry infiltration process is simulated by modelling the scheme of the infiltration column test, in which sedimentation behaviors of slurry particles are captured and compared with experimental results. The results show that the sedimentation behaviors of the slurry particles and filter cake formation phenomenon are well captured by simulations and in accordance with the experiments, which indicates the robustness of the coupled CFD&ndash, DEM simulation used in present work.

This paper presents an analytical solution for the determination of internal forces of a jointed segmental precast DOT (Double-O-tube) lining. The unbalanced force transition method is combined with force method to establish an efficient analytical shortcut that simplifies tests and obtains the solution more effective than the existing methods to determine internal forces in the DOT tunnel lining. The in situ test on a DOT tunnel and a numerical simulation by FEM are conducted to verify the proposed analytical solution. The effects of shoulder ground pressure, soil resistance coefficient and open angle of DOT tunnel on the performance of tunnel lining are discussed as well.

No reports have been published to date on the impact of cardiac rehabilitation (CR) on mortality in patients undergoing combined heart valve and coronary artery bypass graft (CABG) surgery (V + CABG), a procedure that has increased significantly in frequency in recent years.We identified consecutive patients who underwent V + CABG surgery in the Olmsted County from 1996 to 2007. Propensity scores were developed using more than 40 clinical, operative, and post-operative characteristics. The impact of CR on long-term mortality was assessed via landmark analysis and using propensity score regression adjustment and stratification techniques.A total of 201 patients were included in our study, in whom 86 deaths occurred over a mean follow up of 6.8 years. Forty-seven per cent of patients participated in CR, with a significant trend towards increased participation in recent years (p = 0.04). Conditional on 6-month survival and controlling for propensity factors as well as mortality risk factors, CR participation was associated with a significant reduction in mortality (propensity score adjustment: HR 0.48, p = 0.009; propensity score stratification: HR 0.48, p = 0.016). The absolute risk reduction over 10 years was 14.5% (number needed to treat = 7). Results did not differ significantly based on age, gender, emergent status, or history of heart failure or arrhythmias, but CR participation was more beneficial for patients who underwent a mitral valve procedure (HR 0.24, 95% CI 0.08-0.77).This is the first study reporting a significant survival benefit with CR participation in patients who have undergone combined V + CABG surgery. These findings provide evidence in support of recommendations for CR participation after V + CABG surgery.

Background HIV-1 envelope glycoprotein gp120 (gp120) is considered as one of the major virulent proteins responsible for the involvement of the cardiovascular system. Autophagy as a form of self maintenance plays important roles in cell survival and death. HIV-1 gp120 is reported to induce autophagy in a variety of cells. However, the effect of gp120 on autophagy in cardiomyocytes has not been reported. This study aimed to test our hypothesis that gp120 could induce autophagy in cardiomyocytes. Methods Rat cardiomyocyte H9c2 cells were treated with gp120 (100 ng/ml) in vitro for 4 h, 1 day and 7 days. The autophagy related proteins were analyzed by Western blot and the autophagosomes were analyzed by confocal microscopy. Results The autophagic proteins and autophagosomes were markedly increased in the H9c2 cells after 4 h of gp120 treatment. Furthermore, gp120 induced autophagic proteins and autophagosomes were significantly inhibited by the N-methyl- d -aspartic acid (NMDA) receptor inhibitor MK801, c-Jun N-terminal kinase (JNK) inhibitor SP600125, and the class III phosphoinositide 3-kinase (PI3K) inhibitor 3-methyladenine (3-MA), while there was no change in the cells pretreated with the CXCR4 antagonist AMD3100. In addition, no apparent cell death was observed in the cardiomyocytes treated with gp120 for up to 7 days. Conclusions In summary, our research demonstrated for the first time that HIV-1 gp120 could induce autophagy of cardiomyocytes and the NMDA receptor, JNK and class III PI3K were involved in this process. This observation provides a new insight into the mechanisms of in the cardiovascular involvement during HIV-1 infection.

Percutaneous coronary intervention (PCI)-induced myocardial damage is associated with late cardiovascular events. Treatment with atorvastatin before PCI can reduce myocardial damage during the peri-PCI period.To compare the safety and myocardial effects of different atorvastatin loading doses and dosing frequency before PCI in non-ST segment elevation acute coronary syndrome (NSTE-ACS) patients.Eighty NSTE-ACS patients were randomly divided into four groups (20 patients per group). The control group was given 40 mg atorvastatin each night. The three loading dose groups were treated the same as in the control group, but were given 80 mg atorvastatin 12 h before PCI (lowload group) in combination with 40 mg atorvastatin 2 h to 4 h before PCI (mid-load group) or 60 mg atorvastatin 2 h to 4 h before PCI (high-load group). All patients underwent PCI within 48 h to 72 h of admission, and received 40 mg atorvastatin for at least one month after PCI. Changes in myocardial markers and highly sensitive C-reactive protein were analyzed. Patients were followed up for 30 days to monitor the incidence of major adverse cardiac events (MACE).No deaths or revascularizations were recorded. The incidences of MACE differed significantly between the four groups (40%, 25%, 10% and 0% for the control, low-load, mid-load and high-load groups, respectively; P0.05). The incidence of MACE and cardiac troponin I level above the normal range, and post-PCI increases in creatine kinase-MB and highly sensitive C-reactive protein were significantly higher in the control group than in the high-load group (all P0.007). The post-PCI alanine aminotransferase levels in all four groups were significantly higher than the pre-PCI levels, but were within normal ranges. No myalgia or myasthenia was observed.The results of the present study show that short-term atorvastatin loading before PCI was well tolerated and had beneficial myocardial effects in patients with NSTE-ACS.

Geogrids have been widely used as an effective reinforcement in constructions, such as slopes and pavement bases. The mechanism of reinforcement action of geogrids is mainly achieved through the interlocking actions between aggregates and the grids. Different geogrids products and aggregates combinations would significantly affect the effects of interlocking. Accordingly, it is necessary to evaluate the effects of different geogrids on aggregates commonly used in potential engineering projects. In this study, laboratory experimental and analytical investigations were conducted to evaluate the performance of pavement base materials with or without geogrids reinforcement by using cyclic loading system, Loaded Wheel Tester (LWT). Meanwhile, rut depth (vertical deformation) of pavement base was considered to evaluate the effect of improvement.

Deformable models are generally applied to simple images with smooth region boundaries. Segmentation of objects with high curvature shapes (corners) is limited by the models' finite node density and their intrinsic smoothness constraint. Previous solutions to segmentation of objects with corners are based on relating the smoothness constraint at the candidate corner nodes. While allowing a contour to bend at those nodes, these solutions do not provide a force to propel nodes into corners. In this paper, we propose a deformable model algorithm for segmenting objects containing high curvature shapes with subresolution accuracy, which provides a driving force for nodes to slide into corners along object boundaries. The algorithm can be applied to both 2D and 3D deformable models.

The problem of fitting a mesh to a surface, whether defined analytically or by image data, requires consideration of accuracy and attendant computational cost. The accuracy of the surface fit depends on the size of mesh elements. Distributing large mesh elements to surface parts with low curvature and small ones to those with high curvature enables efficient use of mesh elements. In this paper, we propose an algorithm which adapts mesh size to local surface smoothness. Changes in mesh size are accomplished by adaptively adjusting thresholds for division and merger of mesh elements. The primary motivation for developing this algorithm is image segmentation using deformable models and the algorithm was implemented in that context. Tests on a synthetic shape demonstrate the extent to which the local surface smoothness affects the mesh size.

In this paper, we propose fully 3D active surface models for image segmentation. Our models are capable of fitting a diverse range of region shapes. They have low sensitivity to initial shape and position. We design self-inflation/deflation forces, which cooperate naturally with gradient forces. They permit the active surface to travel a long distance without the aid of any external forces. They are easily controlled in both their direction and magnitude. The models produce accurate segmentation when tested with synthetic and real images. They manifest robustness to image noise and imperfect image data. Importantly, they are capable of converging to the correct boundary even if the initial estimate is not close.

A fully 3D active surface model is presented with self-inflation and self-deflation forces. The model makes full use of 3D image information, deforms locally and allowes strong deformation. The self-inflation and self-deflation forces enable the active surface to travel a long distance without the help from any external forces. We introduce a method of adapting model parameters, which enables our model to bypass some noise and irrelevant edge points. The model is tested with synthetic and real images. Accurate segmentation results are obtained in the presence of image noise and imperfect image data. Importantly, the model is capable of converging to the correct boundary even if the initial estimate is not close. Computational efficiency of segmentation with our model is addressed.

When photon scattering around a point source in a scatter medium is considered in isolation, the distribution of the scattering sites is radially symmetric and exponentially decreasing in frequency. Discontinuities in the scattering medium cause a disruption in this radial symmetry. However, when the limited intrinsic energy resolution of the gamma camera, the energy acceptance window and the collimator response are included in the consideration, the distribution of the scattering sites of photons accepted by the gamma camera is complex. Monte Carlo techniques (EGS4) have been used to determine the spatial distribution of the scatter sites. The results of the simulation demonstrate a prominent peak in scattering sites in front of the source with a rapid decrease in all other directions. The contribution of completely backscattered photons to a point spread function is virtually negligible. Also, a clear discontinuity in the scatter site distribution is observed at the boundary of two scatter media. The first order scatter spatial distribution has also been modelled using analytical techniques. The analytical results are in good agreement with the Monte Carlo simulation. Direct experimental verification of the results of the two simulation techniques is not possible, however, there is agreement between secondary results with experimental data, hence the analysis is valid by implication. The knowledge of the scattering site distribution is anticipated to assist in a more accurate method of image reconstruction in SPECT imaging.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.