36 research outputs found

    Multi-energy X-ray linear-array detector enabled by the side-illuminated metal halide scintillator

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    Conventional scintillator-based X-ray imaging typically captures the full spectral of X-ray photons without distinguishing their energy. However, the absence of X-ray spectral information often results in insufficient image contrast, particularly for substances possessing similar atomic numbers and densities. In this study, we present an innovative multi-energy X-ray linear-array detector that leverages side-illuminated X-ray scintillation using emerging metal halide Cs3Cu2I5. The negligible self-absorption characteristic not only improves the scintillation output but is also beneficial for improving the energy resolution for the side-illuminated scintillation scenarios. By exploiting Beer's law, which governs the absorption of X-ray photons with different energies, the incident X-ray spectral can be reconstructed by analyzing the distribution of scintillation intensity when the scintillator is illuminated from the side. The relative error between the reconstructed and measured X-ray spectral was less than 5.63 %. Our method offers an additional energy-resolving capability for X-ray linear-array detectors commonly used in computed tomography (CT) imaging setups, surpassing the capabilities of conventional energy-integration approaches, all without requiring extra hardware components. A proof-of-concept multi-energy CT imaging system featuring eight energy channels was successfully implemented. This study presents a simple and efficient strategy for achieving multi-energy X-ray detection and CT imaging based on emerging metal halides

    Robust Kernel-Based Tracking with Multiple Subtemplates in Vision Guidance System

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    The mean shift algorithm has achieved considerable success in target tracking due to its simplicity and robustness. However, the lack of spatial information may result in its failure to get high tracking precision. This might be even worse when the target is scale variant and the sequences are gray-levels. This paper presents a novel multiple subtemplates based tracking algorithm for the terminal guidance application. By applying a separate tracker to each subtemplate, it can handle more complicated situations such as rotation, scaling, and partial coverage of the target. The innovations include: (1) an optimal subtemplates selection algorithm is designed, which ensures that the selected subtemplates maximally represent the information of the entire template while having the least mutual redundancy; (2) based on the serial tracking results and the spatial constraint prior to those subtemplates, a Gaussian weighted voting method is proposed to locate the target center; (3) the optimal scale factor is determined by maximizing the voting results among the scale searching layers, which avoids the complicated threshold setting problem. Experiments on some videos with static scenes show that the proposed method greatly improves the tracking accuracy compared to the original mean shift algorithm

    Clinicopathological characteristics of synchronous multiple primary early esophageal cancer and risk factors for multiple lesions

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    BackgroundWith the development of endoscopic technology, the detection rate of synchronous multiple primary early esophageal cancer (SMPEEC) is increasing; however, the risk factors remain unclear. We aimed to assess the clinicopathological characteristics of patients with SMPEEC and investigate the risk factors contributing to the development of multiple lesions.MethodsA retrospective cohort study was conducted on 911 consecutive patients who underwent Endoscopic submucosal dissection (ESD) for primary esophageal neoplasms from January 2013 to June 2021. The patients were divided into the SMPEEC group and the solitary early esophageal cancer (SEEC) group. We compared the differences in clinicopathological characteristics between the two groups and investigated the risk factors linked to multiple lesions. Additionally, we investigated the relationship between the main and accessory lesions.ResultsA total of 87 SMPEEC patients were included in this study, and the frequency of synchronous multiple lesions was 9.55% in patients with early esophageal cancer. The lesions in the SMPEEC group were mainly located in the lower segment of the esophagus (46[52.9%]), whereas those in the SEEC group were in the middle segment (412[50.0%]). The pathology type, tumor location, and circumferential rate of lesions were independent risk factors(P<0.05) for SMPEEC by logistic regression analysis. Significant positive correlations were observed between the main and accessory lesions in terms of morphologic type (r=0.632, P=0.000), tumor location(r=0.325, P=0.037), pathologic type (r=0.299, P=0.003), and depth of invasion (r=0.562, P=0.000).ConclusionPathology type, tumor location, and circumferential rate of lesions were identified as independent risk factors for SMEPPC. Understanding these risk factors and the correlation between the main and accessory lesions could significantly improve the detection rate of SMPEEC

    Growth Inhibition and Apoptosis Induced by Osthole, A Natural Coumarin, in Hepatocellular Carcinoma

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    BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most commonly diagnosed tumors worldwide and is known to be resistant to conventional chemotherapy. New therapeutic strategies are urgently needed for treating HCC. Osthole, a natural coumarin derivative, has been shown to have anti-tumor activity. However, the effects of osthole on HCC have not yet been reported. METHODS AND FINDINGS: HCC cell lines were treated with osthole at various concentrations for 24, 48 and 72 hours. The proliferations of the HCC cells were measured by MTT assays. Cell cycle distribution and apoptosis were determined by flow cytometry. HCC tumor models were established in mice by subcutaneously injection of SMMC-7721 or Hepa1-6 cells and the effect of osthole on tumor growths in vivo and the drug toxicity were studied. NF-κB activity after osthole treatment was determined by electrophoretic mobility shift assays and the expression of caspase-3 was measured by western blotting. The expression levels of other apoptosis-related genes were also determined by real-time PCR (PCR array) assays. Osthole displayed a dose- and time-dependent inhibition of the HCC cell proliferations in vitro. It also induced apoptosis and caused cell accumulation in G2 phase. Osthole could significantly suppress HCC tumor growth in vivo with no toxicity at the dose we used. NF-κB activity was significantly suppressed by osthole at the dose- and time-dependent manner. The cleaved caspase-3 was also increased by osthole treatment. The expression levels of some apoptosis-related genes that belong to TNF ligand family, TNF receptor family, Bcl-2 family, caspase family, TRAF family, death domain family, CIDE domain and death effector domain family and CARD family were all increased with osthole treatment. CONCLUSION: Osthole could significantly inhibit HCC growth in vitro and in vivo through cell cycle arrest and inducing apoptosis by suppressing NF-κB activity and promoting the expressions of apoptosis-related genes

    Numerical research on hydrodynamic characteristics of propeller boss cap fins

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    [Objectives] With the increasing popularity of the concept of green ships, marine hydrodynamic energy-saving technology has drawn more attention from researchers. This paper studies the way to reduce energy consumption of ships at sea.[Methods] naoe-FOAM-SJTU solver independently developed by Prof. Wan Decheng's research team in Shanghai Jiao Tong University is used to numerically investigate the hydrodynamic characteristics of Propeller Boss Cap Fins (PBCF). In order to better investigate the interaction between PBCF and propeller,the influences of PBCF on blades,hubs and hub caps are studied respectively.[Results] It is found that the hubs and hub caps are less affected by PBCF, and despite sharp reduction of the propeller torque,the influence of PBCF on the overall thrust is limited. Further it is found that the Reynolds number has great influence on the energy-saving characteristic of PBCF and has a critical value below which the increasing Reynolds number will give rise to greatly improved energy-saving effect,and above which,the energy-saving effect is basically unchanged. This shows that PBCF may have better energy-saving characteristics in the full scale which has the critical Reynolds number.[Conclusions] The findings are satisfactory and shows that the naoe-FOAM-SJTU solver is feasible for the direct simulation of hydrodynamic characteristics of PBCF,and this research method can be applied to other energy-saving devices

    How Guidance Signage Design Influences Passengers’ Wayfinding Performance in Metro Stations: Case Study of a Virtual Reality Experiment

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    Well-designed guidance signage plays a significant role in the metro environment, ensuring that passengers can reach their destination quickly without anxiety and stress. At present, most metro stations in China use vertical guidance signage (hanging on the walls), which can easily cause misunderstandings in conveying information. Horizontal guidance signage (horizontally attached to the ground) with visual continuity has not yet been used. To explore the influence of different signage designs (vertical, horizontal, and mixed) on passengers’ wayfinding performance, this research utilized virtual reality (VR) technology to develop a VR environment based on a metro station in Nanjing, China. Thirty-six volunteers were randomly divided into six groups based on two variables (guidance signage design and density of passengers), and participated in the wayfinding experiment. During the experiment, three types of wayfinding performance measurements were collected and analyzed (subjective: the difference in the pressure of the wayfinding environment on the participants; objective: participants’ average speed, number of pauses, and the selection of infrastructure; systematic: ratings of affordance indicators). The results revealed that the mixed (vertical + horizontal) signage performed best, and different guidance signage designs affect passengers’ perception of environmental pressure, decision-making on the use of public infrastructures (stairs), and the number of pauses

    Equilibrium Strategy Based Recycling Facility Site Selection towards Mitigating Coal Gangue Contamination

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    Environmental pollution caused by coal gangue has been a significant challenge for sustainable development; thus, many coal gangue reduction approaches have been proposed in recent years. In particular, coal gangue facility (CGF) construction has been considered as an efficient method for the control and recycling of coal gangue. Meanwhile, the identification and selection of suitable CGF sites is a fundamental task for the government. Therefore, based on the equilibrium strategy, a site selection approach under a fuzzy environment is developed to mitigate coal gangue contamination, which integrates a geographical information system (GIS) technique and a bi-level model to identify candidate CGF sites and to select the most suitable one. In this situation, the GIS technique used to identify potential feasible sites is able to integrate a great deal of geographical data tofitwithpracticalcircumstances;thebi-levelmodelusedtoscreentheappropriatesitecanreasonably dealwiththeconflictsbetweenthelocalauthorityandthecolliery. Moreover,aKarush–Kuhn–Tucker (KKT) condition-based approach is used to find an optimal solution, and a case study is given to demonstrate the effectiveness of the proposed method. The results across different scenarios show that appropriate site selection can achieve coal gangue reduction targets and that a suitable excess stack level can realize an environmental-economic equilibrium. Finally, some propositions and management recommendations are given

    Virus Propagation in Wireless Sensor Networks with Media Access Control Mechanism

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    In wireless sensor networks, network security against virus propagation is one of the challenges with the applications. In severe cases, the network system may become paralyzed. In order to study the process of virus propagation in wireless sensor networks with the media access control mechanism, this paper uses the susceptible-infectious-removed (SIR) model to analyze the spreading process. It provides a theoretical basis for the development of virus immune mechanisms to solve network virus attack hidden dangers. The research shows that the media access control (MAC) mechanism in the wireless sensor network can inhibit the process of virus propagation, reduce the network virus propagating speed, and decrease the scale of infected nodes. The listen/sleep duty cycle of this mechanism will affect the suppression effect of virus propagation. The smaller the listen/sleep duty cycle, the stronger the suppression effect. Energy consumption has a peak value under specific infection probability. Meanwhile, it is also found that the spreading scale of the virus in wireless sensor networks can be effectively inhibited by the MAC mechanism
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