Search

The hot subdwarf O/B stars (sdO/Bs) are known as extreme horizontal branch stars, which is of great importance in stellar evolution theory. The sdO/Bs are generally thought to have a helium-burning core and a thin hydrogen envelope $(M_{\rm env }<0.02M_\odot)$. In the canonical binary evolution scenario, sdO/Bs are considered to be the stripped cores of red giants. However, such a scenario cannot explain the recently discovered sdO/B binary, SMSS J1920, where the strong Ca H$\&$K lines in the spectrum are found. It suggests that this binary is likely originated from the recent ejection of common envelope (CE). In this {work}, we proposed a new formation channel of massive sdO/Bs, namely sdO/Bs produced from a CE ejection process with an asymptotic giant branch (AGB) star (hereafter AGB CE channel). We constructed the evolutionary model of sdO/Bs and successfully explained most of the important observed parameters of the sdO/B star in SMSS J1920, including the evolutionary age, sdO/B mass, effective temperature, surface gravity and surface helium abundance. The minimum sdO/B mass produced from the AGB CE channel is about $0.48M_\odot$. The evolutionary tracks in $\log T_{\rm eff}-\log g$ plane {may explain a fraction of the observational samples} with high-$\log T_{\rm eff}$ and low-$\log g$. Considering wind mass-loss of sdO/Bs, the model could produce helium-rich hot subdwarfs with $\log (n_{\rm He}/n_{\rm H})\gtrsim-1$., Comment: 9 pages, 5 figures, accepted for publication in ApJ

This letter investigates the challenge of channel estimation in a multiuser millimeter-wave (mmWave) time-division duplexing (TDD) system. In this system, the base station (BS) uses a multi-antenna uniform linear array (ULA), while each mobile user has a fluid antenna system (FAS). Accurate channel state information (CSI) plays a crucial role in the precise placement of antennas in FAS. To tackle this issue, we propose a low-sample-size sparse channel reconstruction (L3SCR) method, capitalizing on the sparse propagation paths of mmWave channels. Simulation results show that our method obtains precise CSI with minimal hardware switching and pilot overhead. As a result, the system sum-rate approaches the upper bound with perfect CSI. IEEE

This letter investigates the performance of content caching in a heterogeneous cellular network (HetNet) consisting of fluid antenna system (FAS)-equipped mobile users (MUs) and millimeter-wave (mm-wave) single-antenna small base stations (SBSs), distributed according to the independent homogeneous Poisson point processes (HPPP). In particular, it is assumed that the most popular contents are cached in the SBSs to serve the FAS-equipped MUs requests. To assess the system performance, we derive compact expressions for the successful content delivery probability (SCDP) and the content delivery delay (CDD) using the Gauss-Laguerre quadrature technique. Our numerical results show that the performance of cache-enabled mm-wave HetNets can be greatly improved, when the FAS is utilized at the MUs instead of traditional fixed-antenna system deployment.

This letter studies the performance of reconfigurable intelligent surface (RIS)-aided communications for a fluid antenna system (FAS) enabled receiver. Specifically, a fixed singleantenna base station (BS) transmits information through a RIS to a mobile user (MU) which is equipped with a planar fluid antenna in the absence of a direct link.We first analyze the spatial correlation structures among the positions (or ports) in the planar FAS, and then derive the joint distribution of the equivalent channel gain at the user by exploiting the central limit theorem. Furthermore, we obtain compact analytical expressions for the outage probability (OP) and delay outage rate (DOR). Numerical results illustrate that using FAS with only one activated port into the RIS-aided communication network can greatly enhance the performance, when compared to traditional antenna systems (TAS).

In contrast to conventional reconfigurable intelligent surface (RIS), simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) has been proposed recently to enlarge the serving area from 180o to 360o coverage. This work considers the performance of a STAR-RIS aided full-duplex (FD) non-orthogonal multiple access (NOMA) communication systems. The STAR-RIS is implemented at the cell-edge to assist the cell-edge users, while the cell-center users can communicate directly with a FD base station (BS). We first introduce new user clustering schemes for the downlink and uplink transmissions. Then, based on the proposed transmission schemes closed-form expressions of the ergodic rates in the downlink and uplink modes are derived taking into account the system impairments caused by the self interference at the FD-BS and the imperfect successive interference cancellation (SIC). Moreover, an optimization problem to maximize the total sum-rate is formulated and solved by optimizing the amplitudes and the phase-shifts of the STAR-RIS elements and allocating the transmit power efficiently. The performance of the proposed user clustering schemes and the optimal STAR-RIS design are investigated through numerical results, Comment: arXiv admin note: text overlap with arXiv:2309.15037

This letter investigates the challenge of channel estimation in a multiuser millimeter-wave (mmWave) time-division duplexing (TDD) system. In this system, the base station (BS) employs a multi-antenna uniform linear array (ULA), while each mobile user is equipped with a fluid antenna system (FAS). Accurate channel state information (CSI) plays a crucial role in the precise placement of antennas in FAS. Traditional channel estimation methods designed for fixed-antenna systems are inadequate due to the high dimensionality of FAS. To address this issue, we propose a low-sample-size sparse channel reconstruction (L3SCR) method, capitalizing on the sparse propagation paths characteristic of mmWave channels. In this approach, each fluid antenna only needs to switch and measure the channel at a few specific locations. By observing this reduced-dimensional data, we can effectively extract angular and gain information related to the sparse channel, enabling us to reconstruct the full CSI. Simulation results demonstrate that our proposed method allows us to obtain precise CSI with minimal hardware switching and pilot overhead. As a result, the system sum-rate approaches the upper bound achievable with perfect CSI., Comment: 6 pages, 4 figures

Different from conventional reconfigurable intelligent surfaces (RIS), a recent innovation called simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) has emerged, aimed at achieving complete 360-degree coverage in communication networks. Additionally, fullduplex (FD) technology is recognized as a potent approach for enhancing spectral efficiency by enabling simultaneous transmission and reception within the same time and frequency resources. In this study, we investigate the performance of a STAR-RIS-assisted FD communication system. The STAR-RIS is strategically placed at the cell-edge to facilitate communication for users located in this challenging region, while cell-center users can communicate directly with the FD base station (BS). We employ a non-orthogonal multiple access (NOMA) pairing scheme and account for system impairments, such as self-interference at the BS and imperfect successive interference cancellation (SIC). We derive closed-form expressions for the ergodic rates in both the up-link and down-link communications and extend our analysis to bidirectional communication between cell-center and cell-edge users. Furthermore, we formulate an optimization problem aimed at maximizing the ergodic sum-rate. This optimization involves adjusting the amplitudes and phase-shifts of the STAR-RIS elements and allocating total transmit power efficiently. To gain deeper insights into the achievable rates of STAR-RIS-aided FD systems, we explore the impact of various system parameters through numerical results.

This letter investigates the application of the emerging fluid antenna (FA) technology in multiuser communication systems when side information (SI) is available at the transmitters. In particular, we consider a K-user dirty multiple access channel (DMAC) with non-causally known SI at the transmitters, where K users send independent messages to a common receiver with a FA capable of changing its location depending on the channel condition. By connecting Jakes' model to copula theory through Spearman's {\rho} rank correlation coefficient, we accurately describe the spatial correlation between the FA channels, and derive a closed-form expression for the outage probability (OP) under Fisher-Snedecor F fading. Numerical results illustrate how considering FA can improve the performance of multiuser communication systems in terms of the OP and also support a large number of users using only one FA at the common receiver in a few wavelengths of space.

This paper investigates the performance of a singleuser fluid antenna system (FAS), by exploiting a class of elliptical copulas to describe the structure of dependency amongst the fluid antenna ports. By expressing Jakes' model in terms of the Gaussian copula, we consider two cases: (i) the general case, i.e., any arbitrary correlated fading distribution; and (ii) the specific case, i.e., correlated Nakagami-m fading. For both scenarios, we first derive analytical expressions for the cumulative distribution function (CDF) and probability density function (PDF) of the equivalent channel in terms of multivariate normal distribution. Then, we obtain the outage probability (OP) and the delay outage rate (DOR) to analyze the performance of the FAS. By employing the popular rank correlation coefficients such as Spearman's \{rho} and Kendall's {\tau}, we measure the degree of dependency in correlated arbitrary fading channels and illustrate how the Gaussian copula can be accurately connected to Jakes' model in FAS without complicated mathematical analysis. Numerical results show that increasing the fluid antenna size provides lower OP and DOR, but the system performance saturates as the number of antenna ports increases. In addition, our results indicate that FAS provides better performance compared to conventional single-fixed antenna systems even when the size of fluid antenna is small.

Driving scene understanding is to obtain comprehensive scene information through the sensor data and provide a basis for downstream tasks, which is indispensable for the safety of self-driving vehicles. Specific perception tasks, such as object detection and scene graph generation, are commonly used. However, the results of these tasks are only equivalent to the characterization of sampling from high-dimensional scene features, which are not sufficient to represent the scenario. In addition, the goal of perception tasks is inconsistent with human driving that just focuses on what may affect the ego-trajectory. Therefore, we propose an end-to-end Interpretable Implicit Driving Scene Understanding (II-DSU) model to extract implicit high-dimensional scene features as scene understanding results guided by a planning module and to validate the plausibility of scene understanding using auxiliary perception tasks for visualization. Experimental results on CARLA benchmarks show that our approach achieves the new state-of-the-art and is able to obtain scene features that embody richer scene information relevant to driving, enabling superior performance of the downstream planning., Comment: Accepted by 26th IEEE International Conference on Intelligent Transportation Systems (ITSC 2023)

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes, with several underlying pathophysiological mechanisms, some of which are still uncertain. The cornea is an avascular tissue and sensitive to hyperglycemia, resulting in several diabetic corneal complications including delayed epithelial wound healing, recurrent erosions, neuropathy, loss of sensitivity, and tear film changes. The manifestation of DPN in the cornea is referred to as diabetic neurotrophic keratopathy (DNK). Recent studies have revealed that disturbed epithelial-neural-immune cell interactions are a major cause of DNK. The epithelium is supplied by a dense network of sensory nerve endings and dendritic cell processes, and it secretes growth/neurotrophic factors and cytokines to nourish these neighboring cells. In turn, sensory nerve endings release neuropeptides to suppress inflammation and promote epithelial wound healing, while resident immune cells provide neurotrophic and growth factors to support neuronal and epithelial cells, respectively. Diabetes greatly perturbs these interdependencies, resulting in suppressed epithelial proliferation, sensory neuropathy, and a decreased density of dendritic cells. Clinically, this results in a markedly delayed wound healing and impaired sensory nerve regeneration in response to insult and injury. Current treatments for DPN and DNK largely focus on managing the severe complications of the disease. Cell-based therapies hold promise for providing more effective treatment for diabetic keratopathy and corneal ulcers.

Ying Yang,1,2 Lingling Li,1,2 Yangyang Zhang,1,2 Hong Yang,1,2 Jia Bai,1,2 Haihong Lv,1,2 Songbo Fu1,2 1Department of Endocrinology, The First Hospital of Lanzhou University, Lanzhou, Gansu, 730000, People’s Republic of China; 2The First Clinical Medical College of Lanzhou University, Lanzhou, Gansu, 730000, People’s Republic of ChinaCorrespondence: Haihong Lv; Songbo Fu, Department of Endocrinology, The First Hospital of Lanzhou University, No. 1Donggang West Road, Lanzhou, Gansu, 730000, People’s Republic of China, Tel +86 13893324091 ; +86 13993122257, Email haihonglv@126.com; 1041685970@qq.comPurpose: The relationship between coronary artery calcification and bone mineral density (BMD) in T2DM is still unclear. The aim of this study is to analyze the association between coronary artery calcium score (CACs) and BMD in T2DM with different visceral fat area (VFA), and further to explore the clinical significance of CACs in predicting osteoporosis in T2DM patients.Patients and Methods: A total of 479 T2DM patients aged ≥ 50 years were included. Agatston was applied to calculate CACs to evaluate the degree of coronary artery calcification. Dual-energy X-ray absorptiometry (DXA) was used to measure BMD. According to VFA, all subjects were divided into VFA < 100cm2 and VFA ≥ 100cm2 group. Adjusted regression analysis was performed to analyze the association between CACs and BMD. ROC curve was used to analyze the optimal cut-off value of CACs for screening osteoporosis.Results: The baseline showed that in VFA ≥ 100cm2 group, CACs increased significantly than that in VFA < 100cm2 group (212.1± 195.9 vs 139.3± 141.8, p< 0.001) and total hip BMD decreased obviously (0.968± 0.19 vs 1.021± 0.184, p=0.01). After multivariable adjustment, CACs was not significantly associated with BMD in all patients (p> 0.05). However, CACs was negatively associated with BMD of total hip and lumbar spine in patients with VFA ≥ 100cm2 (total hip β=− 0.087 p=0.0

Lingling Li,1,2 Ying Yang,1,2 Jia Bai,1,2 Yangyang Zhang,1,2 Hong Yang,1,2 Yuqi Zhang,1,2 Haihong Lv1 1Department of Endocrinology, The First Hospital of Lanzhou University, Lanzhou, Gansu, 730000, People’s Republic of China; 2The First Clinical Medical College of Lanzhou University, Lanzhou, Gansu, 730000, People’s Republic of ChinaCorrespondence: Haihong Lv, Email haihonglv@126.comPurpose: It is believed that vascular endothelial dysfunction is involved in the occurrence of cardiovascular disease (CVD), and diabetic peripheral neuropathy (DPN) is associated with flow-mediated dilation (FMD), however, the correlation is still unclear. Aims of the present study is to explore the relationship between DPN parameters and FMD, providing a new approach for the prevention of CVD.Patients and Methods: A total of 272 patients with T2DM from the Department of Endocrinology of The First Hospital of Lanzhou University according to the grading criteria were selected. FMD was measured by a new vascular ultrasound system and patients were divided into FMD> 7%, 4%≤FMD≤ 7%, and FMD< 4% groups. The Toronto Clinical Scoring System (TCSS) was used to assess the severity of DPN. The nerve conduction studies (NCS) assessed large fibre neuropathy by nerve conduction velocity (CV), compound muscle action potential (CMAP) amplitude (Amp), and distal motor latency (DML). SPSS 25.0 was used for statistical analysis.Results: TCSS evaluation revealed that the percentage of patients with severe nerve injury was significantly higher in FMD< 4% (70%) compared to FMD> 7% (2%). Among the TCSS indicators of all subjects, the proportion of temperature disturbance was the most (73%), and joint position disturbance was the least (0). TCSS scores were negatively correlated with FMD (r=− 0.756, p< 0.001). More interesting, in FMD< 4% group, CV and Amp were positively correlated with FMD, while DML was negatively correlated (p< 0.05). Linear regression analysis model showed

Thin-film nanofabrication is a crucial process in modern integrated circuit technologies. The surface and interfaces introduced as a consequence of the thin film integration often lead to stress effects, morphological alterations, unusual electronic performance, etc. Thus, a thorough understanding of interfacial phenomena for such thin-film materials at the nano-, or even the atomic- scale, is indispensable. In this regard, the transmission electron microscope (TEM) has emerged as one of the most powerful tools for the morphological, structural and crystallographic analysis of interfaces in functional nanomaterials. Since the direct characterization of the interface in thin films plays a pivotal role in understanding the relationship between form and function, the motivation of this thesis is to utilize various TEM techniques to observe the interfacial phenomena of functional – in particular ferroelectric – films. Combining atomic-scale aberration corrected imaging with in-situ stimulus methods, real-time domain switching behaviors induced by specific boundary conditions are investigated. The thesis focuses on two main thin-film ferroelectric systems: Pb(Zr, Ti)O3 (PZT) and BiFeO3 (BFO). First, the motion of ferroelastic domain walls in a tetragonal (T) PZT/rhombohedral (R) PZT epitaxial bilayer has been studied to understand the origins of previously-reported enhanced electromechanical response in such thin-film systems. This is followed by a detailed probing of the thickness dependence in such PZT bilayer series (grown on silicon), where we find a strong correlation between film thickness and the resultant fine domain structures. In the second part of the thesis, an investigation of the effects of the electrode and the substrate on domain switching in epitaxial BFO thin-film system was carried out. A further aspect, i.e., the role of antiphase boundaries on deterministic domain switching behaviors in the BFO thin films, was also investigated. These experiments rev

Most subdwarf B (sdB) + Helium white dwarf (He WD) binaries are believed to be formed from a particular channel. In this channel, the He WDs are produced first from red giants (RGs) with degenerate cores via stable mass transfer and sdB stars are produced from RGs with degenerate cores via common envelope (CE) ejection. They are important for the studies of CE evolution, binary evolution, and binary population synthesis. However, the relation between WD mass and orbital period of sdB + He WD binaries has not been specifically studied. In this paper, we first use a semi-analytic method to follow their formation and find a WD mass and orbital period relation. Then we use a detailed stellar evolution code to model their formation from main-sequence binaries. We find a similar relation between the WD mass and orbital period, which is in broad agreement with observations. For most sdB + He WD systems, if the WD mass (orbital period) can be determined, the orbital period (WD mass) can be inferred with this relation and then the inclination angle can be constrained with the binary mass function. In addition, we can also use this relation to constrain the CE ejection efficiency and find that a relative large CE ejection efficiency is favoured. If both the WD and sdB star masses can be determined, the critical mass ratios of dynamically unstable mass transfer for RG binaries can also be constrained., Comment: 6 pages, 5 figures, accepted for publication in MNRAS

Fei Gao,1,&ast; Lingtong Shan,2,&ast; Chong Wang,3,&ast; Xiaoqi Meng,4 Jiapeng Chen,5 Lixiang Han,6 Yangyang Zhang,3 Zhi Li6 1Cardiovascular Department, Huaiyin Hospital of Huai’an City, Huai’an, Jiangsu, People’s Republic of China; 2Department of Thoracic Surgery, Sheyang County People’s Hospital, Yancheng, Jiangsu, People’s Republic of China; 3Department of Cardiovascular Surgery, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, People’s Republic of China; 4The Second Clinical Medical College of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China; 5Xinglin College, Nantong University, Nantong, Jiangsu, People’s Republic of China; 6Department of Cardiovascular Surgery, Jiangsu Province Hospital, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Zhi LiDepartment of Cardiovascular Surgery, Jiangsu Province Hospital, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, 210029, People’s Republic of ChinaTel +86 13770606815Email zhili_cths@163.comYangyang ZhangDepartment of Cardiac Surgery, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 Huaihai West Road, Shanghai, 200120, People’s Republic of ChinaTel +86 13818132320Email zhangyangyang_wy@vip.sina.comObjective: To evaluate the powers of European Heart Surgery Risk Assessment System II (EuroSCORE II) and the Society of Thoracic Surgeons (STS) score in predicting in-hospital and medium-term mortality of patients undergoing coronary artery bypass grafting (CABG).Methods: Totally 1628 Chinese patients were included between January 2000 and January 2018. Their perioperative clinical data were collected and the patients were closely followed up. According to the length of follow-up time, the total cohort was divided into 1-year, 2-year, 3-year, 4-year and 5-year groups. The in-hosp

Yuying Gu,1,* Lingtong Shan,2,* Ban Liu,3,* Mengwei Lv,4 Xi Chen,4 Tao Yan,5 Yu Shi,4 Jiapeng Chen,6 Zhi Li,7 Yangyang Zhang4 1Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, People’s Republic of China; 2Department of Thoracic Surgery, Sheyang County People’s Hospital, Yancheng, Jiangsu, People’s Republic of China; 3Department of Cardiology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, People’s Republic of China; 4Department of Cardiovascular Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, People’s Republic of China; 5Department of Cardiovascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, People’s Republic of China; 6Xinglin College, Nantong University, Nantong, Jiangsu, People’s Republic of China; 7Department of Cardiovascular Surgery, Jiangsu Province Hospital, The First Affiliated Hospital with Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yangyang ZhangDepartment of Cardiovascular Surgery, Shanghai East Hospital, Tongji University School of Medicine, 150 Jimo Road, Shanghai, 200120, People’s Republic of ChinaTel +86 13818132320Email zhangyangyang_wy@vip.sina.comZhi LiDepartment of Cardiovascular Surgery, Jiangsu Province Hospital, The First Affiliated Hospital with Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of ChinaTel +86 13770606815Email zhili_cths@163.comBackground: Cardiac troponin T (cTnT) is currently one of the important indicators for clinical diagnosis of myocardial injury, which is inevitable in cardiac surgery, especially coronary artery bypass grafting (CABG). Describing the release profile of cTnT and finding out the risk factors of postoperative myocardial injury (PMI) are of great significance. The p

Fluid antenna represents a concept where a mechanically flexible antenna can switch its location freely within a given space. Recently, it has been reported that even with a tiny space, a single-antenna fluid antenna system (FAS) can outperform an L-antenna maximum ratio combining (MRC) system in terms of outage probability if the number of locations (or ports) the fluid antenna can be switched to, is large enough. This letter aims to study if extraordinary capacity can also be achieved by FAS with a small space. We do this by deriving the ergodic capacity, and a capacity lower bound. This letter also derives the level crossing rate (LCR) and average fade duration (AFD) for the FAS., Comment: 4 pages, 5 figures

Complementary to traditional approaches that focus on transceiver design for bringing the best out of unstable, lossy fading channels, one radical development in wireless communications that has recently emerged is to pursue a smart radio environment by using software-defined materials or programmable metasurfaces for establishing favourable propagation conditions. This article portraits a vision of communication superhighways enabled by surface wave (SW) propagation on "smart surfaces" for future smart radio environments. The concept differs from the mainstream efforts of using passive elements on a large surface for bouncing off radio waves intelligently towards intended user terminals. In this vision, energy efficiency will be ultra-high, due to much less pathloss compared to free space propagation, and the fact that SW is inherently confined to the smart surface not only greatly simplifies the task of interference management, but also makes possible exceptionally localized high-speed interference-free data access. We shall outline the opportunities and associated challenges arisen from the SW paradigm. We shall also attempt to shed light on several key enabling technologies that make this realizable. One important technology which will be discussed is a software-controlled fluidic waveguiding architecture that permits dynamic creation of high-throughput data highways., Comment: 7 pages, 6 figures

Over the past decades, multiple antenna technologies have appeared in many different forms, most notably as multiple-input multiple-output (MIMO), to transform wireless communications for extraordinary diversity and multiplexing gains. The variety of technologies has been based on placing a number of antennas at fixed locations which dictates the fundamental limit on the achievable performance. By contrast, this paper envisages the scenario where the physical position of an antenna can be switched freely to one of the N positions over a fixed-length line space to pick up the strongest signal in the manner of traditional selection combining. We refer to this system as a fluid antenna system (FAS) for tremendous flexibility in its possible shape and position. The aim of this paper is to study the achievable performance of a single-antenna FAS system with a fixed length and N in arbitrarily correlated Rayleigh fading channels. Our contributions include exact and approximate closed-form expressions for the outage probability of FAS. We also derive an upper bound for the outage probability, from which it is shown that a single-antenna FAS given any arbitrarily small space can outperform an L-antenna maximum ratio combining (MRC) system if N is large enough. Our analysis also reveals the minimum required size of the FAS, and how large N is considered enough for the FAS to surpass MRC., Comment: 26 pages, 5 figures

Zhi Li,1,* Wen Ge,2,* Chunyan Han,3,* Mengwei Lv,4,5,* Yanzhong He,5 Juntao Su,6 Ban Liu,3 Yangyang Zhang5 1Department of Cardiovascular Surgery, Jiangsu Province Hospital, The First Affiliated Hospital of Nanjing Medical University, Nanjing, People’s Republic of China; 2Department of Thoracic and Cardiovascular Surgery, Shuguang Hospital, Shanghai University of TCM, Shanghai, People’s Republic of China; 3Department of Cardiology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, People’s Republic of China; 4Shanghai East Hospital of Clinical Medicine College, Nanjing Medical University, Shanghai, People’s Republic of China; 5Department of Cardiovascular Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, People’s Republic of China; 6Tongji University School of Medicine, Shanghai, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yangyang Zhang; Ban Liu Email zhangyangyang_wy@tongji.edu.cn; 2013liuban@tongji.edu.cnBackground: Renal dysfunction is independently associated with both short-term and long-term mortality after coronary artery bypass grafting (CABG). The estimated glomerular filtration rate (eGFR) is a convenient and effective indicator of renal function. However, the ability of eGFR calculated by various equations to predict the outcomes of patients undergoing off-pump CABG (OPCABG) is still unclear. This study was aimed to compare the predictive ability of in-hospital and long-term mortality in three equations of estimating renal functions after OPCABG.Methods: Totally, 1362 patients undergoing OPCABG were retrospectively reviewed. Preoperative and postoperative serum creatinine (Scr) levels were detected. The renal function was evaluated by the Cockcroft-Gault (CG) equation, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, and the full-age spectrum (FAS) equatio

Stringent emission controls during the Asia Pacific Economic Cooperation Summit (APEC; November 5–11, 2014) provide a valuable opportunity to examine the impact of such measures on the chemical properties of PM2.5 and other air pollutants. Here, we measured the water-soluble inorganic ions (WSII) and carbonaceous species in PM2.5, NH3 and NO2 at multiple sites in Beijing between September and November 2014. Relative to the pre-APEC period (September and October 2014), significant reductions in the average concentrations of WSII (69% for NO3−, 68% for SO42−, 78% for NH4+, and 29–71% for other species), elemental carbon (EC, 43%) and organic carbon (OC, 45%) in PM2.5 were found during the APEC period. The contributions of secondary inorganic ions (SIA, including SO42−, NO3−, and NH4+) to PM2.5 were significantly lower during the APEC period (9–44%), indicating a combination of lower gaseous precursor emissions and a relative weak secondary aerosol formation. Ion-balance calculations indicated that the PM2.5 sample in the pre-APEC period was alkaline but was acidic during the APEC period. Relatively lower mean concentrations of EC (1.5 μg m−3), OC (10.5 μg m−3), secondary organic carbon (SOC, 3.3 μg m−3), secondary organic aerosol (SOA, 5.9 μg m−3) and primary organic aerosol (POA, 10.0 μg m−3) appeared during the APEC period. The average concentrations of NH3 and NO2 at all road sites were significantly reduced by 48 and 60% during the APEC period, which is consistent with clear reductions in satellite NH3 columns over Beijing city in the same period. This finding suggests that reducing traffic emissions could be a feasible method to control urban NH3 pollution. During the APEC period, concentrations of PM2.5, PM10, NO2, SO2 and CO from the Beijing city monitoring network showed significant reductions at urban (20–60%) and rural (18–57%) sites, whereas O3 concentrations increased significantly (by 93% and 53%, respectively). The control measures taken in the APEC peri

Yangyang Zhang,1,2 Qiaoli Niu,2 Wenguo Fan,1 Fang Huang,1 Hongwen He11Guanghua School of Stomatology, Institute of Stomatological Research, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, People’s Republic of China; 2The Oral Medicine Clinical Center, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang Uygur Autonomous Region, People’s Republic of ChinaAbstract: The microbiota inhabiting the oral cavity is a complex ecosystem and responsible for resisting pathogens, maintaining homeostasis, and modulating the immune system. Some components of the oral microbiota contribute to the etiology of some oral diseases. Accumulating evidence suggests that the human oral microbiota is implicated in the development and progression of gastrointestinal cancer. In this review, we described the current understanding of possible roles and mechanisms of oral microbiota in the gastrointestinal cancers studied to date. The perspectives for oral microbiota as the biomarkers for early detection and new therapeutic targets were also discussed.Keywords: oral microbiota, gastrointestinal cancer, etiology

Non-orthogonal multiple access (NOMA) has recently received much attention as a candidate technique for the fifth generation networks. In this paper, considering both the direct and relay-aid paths, we investigate the performance of a downlink NOMA-based cooperative system and further analyze two different user ordering schemes. The outage probability, diversity gain, and ergodic rate are studied as three benchmarks to evaluate the system performance. For different user ordering schemes, the exact outage probabilities of users are first solved in the closed form. Then, the outage behavior in the high signal-to-noise ratio (SNR) region is discussed to obtain the diversity gain. In addition, the closed-form expression of ergodic rate for the strongest user and upper bounds for the rest users at high SNR is provided. Finally, numerical results verify the accuracy of our analysis and demonstrate that sorting users based on the relay-aided path can provide a larger ergodic sum rate in some cases. By contrast, sorting users based on the direct path can provide a better diversity gain, and the corresponding performance is less sensitive to relay's location.

In this paper, we investigate a simultaneous wireless information and power transfer (SWIPT) based two-way decode-and-forward (DF) relay network, where time switching (TS) is employed for SWIPT and time division broadcast (TDBC) is employed for two-way relaying. We focus on the design of a combining scheme that decides how the relay combines the signals received from two terminals through a power allocation ratio at the relay. We formulate an optimization problem to minimize the system outage probability and obtain the optimal power allocation ratio in closed form. For the proposed optimal combining scheme, we derive the expressions for the system outage probability and capacity. Simulation results verify our derived expressions and show that the proposed scheme achieves a higher system outage capacity than the existing schemes., Comment: This paper has been accepted by IEEE Wireless Communications Letters

In this paper, we study the coexistence and synergy between edge and central cloud computing in a heterogeneous cellular network (HetNet), which contains a multi-antenna macro base station (MBS), multiple multi-antenna small base stations (SBSs) and multiple single-antenna user equipment (UEs). The SBSs are empowered by edge clouds offering limited computing services for UEs, whereas the MBS provides high-performance central cloud computing services to UEs via a restricted multiple-input multiple-output (MIMO) backhaul to their associated SBSs. With processing latency constraints at the central and edge networks, we aim to minimize the system energy consumption used for task offloading and computation. The problem is formulated by jointly optimizing the cloud selection, the UEs' transmit powers, the SBSs' receive beamformers, and the SBSs' transmit covariance matrices, which is {a mixed-integer and non-convex optimization problem}. Based on methods such as decomposition approach and successive pseudoconvex approach, a tractable solution is proposed via an iterative algorithm. The simulation results show that our proposed solution can achieve great performance gain over conventional schemes using edge or central cloud alone. Also, with large-scale antennas at the MBS, the massive MIMO backhaul can significantly reduce the complexity of the proposed algorithm and obtain even better performance., Comment: Accepted in IEEE Transactions on Wireless Communications

This dissertation is dedicated to the study of three dimensional transport in toroidal magnetic configurations induced by the presence of the magnetic islands, which break the nested flux surfaces and make the magnetic field intrinsically three dimensional. The methodology applied is based on defining a certain symmetry so that the transport study could be performed in the approximation of 1.5 dimensions. The work has been carried out on both RFX-mod Reversed Field Pinch (RFP) and the TJ-II stellarator. RFX-mod is the largest RFP in the world. The RFP configuration is sustained by the so-called dynamo mechanism, which is related to the non-linear interactions among many resonating MHD tearing modes. The transport study on RFX-mod has been performed on the three sub-states identified in the Quasi-Single Helicity regime, that features one single mode (dominant mode) dominating the mode spectrum, while the rest of the modes (secondary modes) remain at low amplitudes. In this regime proper flux coordinates can be identified considering an equilibrium built on the underlying axi-symmetric magnetic field plus the contribution from the dominant mode. In this way, a 1.5 dimensional approximation transport study is possible by averaging different physical quantities over the flux surfaces. The transport study is focused on the bean-shaped region where nearly conserved flux surfaces have been identified, on which the formation of steep thermal gradients is observed, interpreted as electron Internal Transport Barrier (eITB). Starting from experimental measurements, both the thermal gradients and the thermal diffusivity have been calculated and their behaviors have been discussed within the framework of stochastic transport. Finally, the energy confinement time has also been evaluated, adopting an improved method with respect to past studies, and the results show a significant improvement. The transport study on TJ-II stellarator focuses on the calculation of the enhanced non-a

The implementation of strict emission control measures in Beijing and surrounding regions during the 2015 China Victory Day Parade provided a valuable opportunity to investigate related air quality improvements in a megacity. We measured NH3, NO2 and PM2.5 at multiple sites in and outside Beijing and summarized concentrations of PM2.5, PM10, NO2, SO2 and CO in 291 cities across China from a national urban air quality monitoring network between August and September 2015. Consistently significant reductions of 12–35 % for NH3 and 33–59 % for NO2 in different areas of Beijing during the emission control period (referred to as the Parade Blue period) were observed compared with measurements in the pre- and post-Parade Blue periods without emission controls. Average NH3 and NO2 concentrations at sites near traffic were strongly correlated and showed positive and significant responses to traffic reduction measures, suggesting that traffic is an important source of both NH3 and NOx in urban Beijing. Daily concentrations of PM2.5 and secondary inorganic aerosol (sulfate, ammonium and nitrate) at the urban and rural sites both decreased during the Parade Blue period. During (after) the emission control period, concentrations of PM2.5, PM10, NO2, SO2 and CO from the national city-monitoring network showed the largest decrease (increase) of 34–72 % (50–214 %) in Beijing, a smaller decrease (a moderate increase) of 1–32 % (16–44 %) in emission control regions outside Beijing and an increase (decrease) of 6–16 % (−2–7 %) in non-emission-control regions of China. Integrated analysis of modelling and monitoring results demonstrated that emission control measures made a major contribution to air quality improvement in Beijing compared with a minor contribution from favourable meteorological conditions during the Parade Blue period. These results show that controls of secondary aerosol precursors (NH3, SO2 and NOx) locally and regionally are key to curbing air pollution in Beijing a

This paper investigates a multiuser multiple-input single-output (MISO) full-duplex (FD) system for simultaneous wireless information and power transfer (SWIPT), in which a multi-antenna base station (BS) simultaneously sends wirelessly information and power to a set of single-antenna mobile stations (MSs) using power splitters (PSs) in the downlink and receives information in the uplink in FD mode. In particular, we address the joint design of the receive PS ratio and the transmit power at the MSs, and the beamforming matrix at the BS under signal-to-interference-plus-noise ratio (SINR) and the harvested power constraints. Using semidefinite relaxation (SDR), we obtain the solution to the problem with imperfect channel state information (CSI) of the self-interfering channels. Furthermore, we propose another suboptimal zero-forcing (ZF) based solution by separating the optimization of the transmit beamforming vector and the PS ratio. Simulation results are provided to evaluate the performance of the proposed beamforming designs.

This letter studies bi-directional secure information exchange in a simultaneous wireless information and power transfer (SWIPT) system enabled by a full-duplex (FD) multiple-input multiple-output (MIMO) amplify-and-forward (AF) relay. The AF relay injects artificial noise (AN) in order to confuse the eavesdropper. Specifically, we assume a zeroforcing (ZF) solution constraint to eliminate the residual self-interference (RSI). As a consequence, we address the optimal joint design of the ZF matrix and the AN covariance matrix at the relay node as well as the transmit power at the sources. We propose an alternating algorithm utilizing semi-definite programming (SDP) technique and one-dimensional searching to achieve the optimal solution. Simulation results are provided to demonstrate the effectiveness of the proposed algorithm., Comment: Submitted to IEEE Wireless Communications Letters

Le contrôle de la pollution environnementale provoquée par les humains et ses influences sur les activités économiques est un sujet de plus en plus populaire depuis les années 80. Beaucoup de chercheurs s’y intéressent afin de trouver les effets de la politique environnementale sur les activités économiques. Ce mémoire a donc pour but d’étudier et d’analyser le Programme canadien de lutte contre les pluies acides (PCLCPA), né en 1985 pour contrôler les pluies acides dans les provinces de l’Est du Canada, qui est l’endroit le plus endommagé par les pluies acides. L’Effet de havre de pollution est la théorie sur laquelle nous nous sommes appuyés dans notre recherche. Nous avons supposé au préalable que le PCLCPA crée un effet positif sur les importations interprovinciales dans les provinces de l’Est du Canada, dans les secteurs industriels qui sont les plus polluants et qui sont classés selon quatre indicateurs d’intensité. Pour vérifier la robustesse des résultats, les importations internationales ainsi que les exportations interprovinciales et internationales sont retenues. En employant la méthode de triple-différence, nos résultats montrent que le PCLCPA n’a pas un effet significatif sur les flux commerciaux canadiens. Les raisons principales pour expliquer un tel résultat portent sur, premièrement, la qualité insuffisante des bases de données; deuxièmement, la structure régionale de l’économie canadienne, qui est la cause majeure de l’échange interprovincial et international canadien, et non le PCLCPA; troisièmement, l’Accord de Libre-Échange entre le Canada et les États-Unis (ALE) a un impact possible sur le commerce international du Canada (avec des conséquences pour le commerce interprovincial également).

NAH method in non-free sound field reconstruction of the sound source will lead to considerable error. This paper proposes a method to reconstruct the sound source in a closed space. In the closed space, the total sound pressure is the sum of the source radiation pressure and the reflected sound pressure from medium interface. Reflections from medium interface is a convolution noise, rather than additive noise. In order to reconstruct a sound source in the closed space, in this paper we first adopt the complex cepstrum method to separate and radiation pressure and the reflected sound pressure, then filter them to reduction of reflected sound pressure, and then reconstruct the sound source. The simulation results show the correctness and effectiveness of the method.

According to longitudinal vibration differential equations of ship propulsion shafting, deduced transfer matrix of propeller, uniform shaft segment and thrust bearing which composed propulsion shafting. Given longitudinal vibration natural frequency of propulsion shafting using the transfer matrix solver, and compared with finite element simulation results to verify the accuracy of the finite element model. Then analysis the effect of elastic coupling axial stiffness on modal frequencies of shafting longitudinal vibration and vibration isolation performance through simulation. Results show that: elastic coupling can effectively isolate the propulsion shafting vibration transmitted to the propulsion motor; when the axial stiffness ratio of thrust bearing and elastic coupling is greater than 50, the impact of elastic coupling axial stiffness on longitudinal vibration natural frequency of propulsion shafting and acceleration level and axial displacement of thrust bearing is very small; when the stiffness ratio is greater than 100, the elastic coupling can achieve better vibration isolation effect.

The acoustic field reconstruction using the statistical optimal near-field acoustic holography can avoid the winding error, but the finite aperture error cannot be avoided. In order to reduce the finite aperture error, the data extrapolation technique is used before the separation of the sound field. Numerical simulation shows that the method can effectively reduce the reconstruction error.

As common structure of underwater vehicle, the accurate prediction of underwater vibration and acoustic radiation of double cylindrical shell is always a difficult problem in the research of vibration and noise. Establish finite element model of double cylindrical shell in Abaqus software. Based on the three-dimensional sono-elasticity theory of ships, analysis vibration and acoustic radiation characteristics of underwater double cylindrical shell by the use of Thafts-acoustic software, and compared with experimental result. Results show that error of prediction result and experiment result at single frequency point is about 10 %~20 %, and error of total level of acceleration and sound pressure is less than 5 dB. It is accurate to predict the underwater vibration and acoustic radiation characteristics of double cylindrical shell with three-dimensional sono-elasticity theory of ships, which can provide new effective guidance for the engineering application.

This paper considers simultaneous wireless information and power transfer (SWIPT) in a multiple-input single-output (MISO) downlink system consisting of one multi-antenna transmitter, one single-antenna information receiver (IR), multiple multi-antenna eavesdroppers (Eves) and multiple single-antenna energy-harvesting receivers (ERs). The main objective is to keep the probability of the legitimate user's achievable secrecy rate outage as well as the ERs' harvested energy outage caused by channel state information (CSI) uncertainties below some prescribed thresholds. As is well known, the secrecy rate outage constraints present a significant analytical and computational challenge. Incorporating the energy harvesting (EH) outage constraints only intensifies that challenge. In this paper, we address this challenging issue using convex restriction approaches which are then proved to yield rank-one optimal beamforming solutions. Numerical results reveal the effectiveness of the proposed schemes., Comment: This is an open access article accepted for publication as a regular paper in the IEEE Transactions on Information Forensics & Security. Copyright (c) 2016 IEEE. Personal use of this material is permitted. However, permission to use this material for any other purposes must be obtained from the IEEE by sending a request to pubs-permissions@ieee.org

We present a novel parametric message representation for belief propagation (BP) that provides a novel grid-based way to address the cooperative localization problem in wireless networks. The proposed Grid-BP approach allows faster calculations than non-parametric representations and works well with existing grid-based coordinate systems, e.g., NATO's military grid reference system (MGRS). This overcomes the hidden challenge inherent in all distributed localization algorithms that require a universally known global reference system (GCS), even though every node localizes using arbitrary local coordinate systems (LCSs) for a reference. Simulation results demonstrate that Grid-BP achieves similar accuracy at much reduced complexity when compared to common techniques that assume ideal reference

In this letter, we propose a novel receive antenna selection algorithm based on cross entropy optimization to maximize the capacity over spatially correlated channels in multiple-input multiple-output (MIMO) wireless systems. The performance of the proposed algorithm is investigated and compared with the existing schemes. Simulation results show that our low complexity algorithm can achieve near-optimal results that converge to within 99% of the optimal results obtained by exhaustive search. In addition, the proposed algorithm achieves near-optimal results irrespective of the mutual relationship between the number of transmit and receive antennas, the statistical properties of the channel and the operating signal-to-noise ratio., Engineering and Physical Sciences Research Council (Grant GR/T21769/01)

In this paper, a novel low-complexity antenna-selection algorithm based on a constrained adaptive Markov chain Monte Carlo (CAMCMC) optimization method is proposed to approach the maximum capacity or minimum bit error rate (BER) of receive-antenna-selection multiple-input multiple-output (MIMO)-orthogonal frequency division multiplexing (OFDM) systems. We analyze the performance of the proposed system as the control parameters are varied and show that both the channel capacity and the system BER achieved by the proposed CAMCMC selection algorithm are close to the optimal results obtained by the exhaustive search (ES) method. We further demonstrate that this performance can be achieved with less than 1% of the computational complexity of the ES rule and is independent of the antenna-selection criteria, outage rate requirements, antenna array configuration, and channel frequency selectivity. Similar to the existing antenna-selection algorithms, both channel capacity and system BER improvements achieved by the proposed CAMCMC method are reduced as the channel frequency selectivity increases. Therefore, we conclude that, whether it is designed to maximize the channel capacity or minimize the system BER, the CAMCMC-optimization-method-based antenna-selection technique is appropriate for a MIMO-OFDM system with low frequency selectivity.