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A block zero-padding method based on DCFT for L1 parameter estimations in weak signal and high dynamic

Chao WU,Lu-ping XU,Hua ZHANG,Wen-bo ZHAO

《信息与电子工程前沿（英文）》 2015年第16卷第9期页码 796-804 doi: 10.1631/FITEE.1500058

摘要： Weak L1 signal acquisition in a high dynamic environment primarily faces a challenge: the integration peak is negatively influenced by the possible bit sign reversal every 20 ms and the frequency error. The block accumulating semi-coherent integration of correlations (BASIC) is a state-of-the-art method, but calculating the inter-block conjugate products restricts BASIC in a low signal-to-noise ratio (SNR) acquisition. We propose a block zero-padding method based on a discrete chirp-Fourier transform (DCFT) for parameter estimations in weak signal and high dynamic environments. Compared with the conventional receiver architecture that uses closed-loop acquisition and tracking, it is more suitable for open-loop acquisition. The proposed method combines DCFT and block zero-padding. In this way, the post-correlation signal is coherently post-integrated with the bit sequence stripped off, and the high dynamic parameters are precisely estimated using the threshold set based on a false alarm probability. In addition, the detection performance of the proposed method is analyzed. Simulation results show that compared with the BASIC method, the proposed method can precisely detect the high dynamic parameters in lower SNR when the length of the received signal is fixed.

关键词： Threshold detection Discrete chirp-Fourier transform Block zero-padding High dynamic Weak L1 signal acquisition

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Extended stochastic resonance (SR) and its applications in weak mechanical signal processing

Niaoqing HU, Min CHEN, Guojun QIN, Lurui XIA, Zhongyin PAN, Zhanhui FENG,

《机械工程前沿（英文）》 2009年第4卷第4期页码 450-461 doi: 10.1007/s11465-009-0072-3

摘要： To catch symptoms of machine failure as early as possible, one of the most important strategies is to apply more progressive techniques during signal processing. This paper presents a method based on stochastic resonance (SR) to detect weak fault signal. First, a discrete model of a bistable system that can demonstrate SR is researched, and the stability condition for controlling the selection of model parameters of the discrete model and guarantee the solving convergence are established. Then, the frequency range of the weak signals that the SR model can detect is extended through a type of normalized scale transformation. Finally, the method is applied to extract the weak characteristic component from heavy noise to indicate the little crack fault in a bearing outer circle.

关键词： extended stochastic resonance (SR) stability analysis of SR scale transform weak signal detection incipient fault detection envelope analysis

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PD-1/PD-L1 blockade in cervical cancer: current studies and perspectives

Yumeng Wang, Guiling Li

《医学前沿（英文）》 2019年第13卷第4期页码 438-450 doi: 10.1007/s11684-018-0674-4

摘要： Cervical cancer (CC) is the fourth most commonly diagnosed female malignancy and a leading cause of cancer-related mortality worldwide, especially in developing countries. Despite the use of advanced screening and preventive vaccines, more than half of all CC cases are diagnosed at advanced stages, when therapeutic options are extremely limited and side effects are severe. Given these circumstances, new and effective treatments are needed. In recent years, exciting progress has been made in immunotherapies, including the rapid development of immune checkpoint inhibitors. Checkpoint blockades targeting the PD-1/PD-L1 axis have achieved effective clinical responses with acceptable toxicity by suppressing tumor progression and improving survival in several tumor types. In this review, we summarize recent advances in our understanding of the PD-1/PD-L1 signaling pathway, including the expression patterns of PD-1/PD-L1 and potential PD-1/PD-L1-related therapeutic strategies for CC.

关键词： PD-1 PD-L1 immune checkpoint blockade antibody immunotherapy cervical cancer

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Metabolic interventions combined with CTLA-4 and PD-1/PD-L1 blockade for the treatment of tumors: mechanisms

《医学前沿（英文）》页码 805-822 doi: 10.1007/s11684-023-1025-7

摘要： Immunotherapies based on immune checkpoint blockade (ICB) have significantly improved patient outcomes and offered new approaches to cancer therapy over the past decade. To date, immune checkpoint inhibitors (ICIs) of CTLA-4 and PD-1/PD-L1 represent the main class of immunotherapy. Blockade of CTLA-4 and PD-1/PD-L1 has shown remarkable efficacy in several specific types of cancers, however, a large subset of refractory patients presents poor responsiveness to ICB therapy; and the underlying mechanism remains elusive. Recently, numerous studies have revealed that metabolic reprogramming of tumor cells restrains immune responses by remodeling the tumor microenvironment (TME) with various products of metabolism, and combination therapies involving metabolic inhibitors and ICIs provide new approaches to cancer therapy. Nevertheless, a systematic summary is lacking regarding the manner by which different targetable metabolic pathways regulate immune checkpoints to overcome ICI resistance. Here, we demonstrate the generalized mechanism of targeting cancer metabolism at three crucial immune checkpoints (CTLA-4, PD-1, and PD-L1) to influence ICB therapy and propose potential combined immunotherapeutic strategies co-targeting tumor metabolic pathways and immune checkpoints.

关键词： CTLA-4 PD-1 PD-L1 immune checkpoint blockade (ICB) metabolic reprogramming combined tumor therapeutic strategies

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紧凑型计算光谱信息采集系统综述 Review Articles

宋洪亚1,张文屹1,李海峰1,刘旭1,2,3,郝翔1

《信息与电子工程前沿（英文）》 2020年第21卷第8期页码 1119-1266 doi: 10.1631/FITEE.1900266

摘要：随着计算机科学的发展，越来越多硬件功能可通过软件编程实现，使得光学仪器更加紧凑、廉价，光学设计和加工也更加方便、快速。近年来，软件算法被引入光谱检测，发展出一些计算型的光谱仪、光谱成像设备等光谱信息采集系统。通过与传统非计算方法比较，本文突出了计算光谱采集的优势。重点关注紧凑性特征，回顾最具代表性的计算光谱信息采集系统，并作讨论和展望。

关键词：光谱成像；计算成像；光谱仪

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Activation of phagocytosis by immune checkpoint blockade

null

《医学前沿（英文）》 2018年第12卷第4期页码 473-480 doi: 10.1007/s11684-018-0657-5

摘要：

Inhibition of macrophage-mediated phagocytosis has emerged as an essential mechanism for tumor immune evasion. One mechanism inhibiting the innate response is the presence of the macrophage inhibitory molecule, signal regulatory protein-α (SIRPα), on tumor-associated macrophages (TAMs) and its cognate ligand cluster of differentiation 47 (CD47) on tumor cells in the tumor microenvironment. On the basis of a recently discovered programmed death protein 1 (PD-1) in TAMs, we discuss the potential inhibitory receptors that possess new functions beyond T cell exhaustion in this review. As more and more immune receptors are found to be expressed on TAMs, the corresponding therapies may also stimulate macrophages for phagocytosis and thereby provide extra anti-tumor benefits in cancer therapy. Therefore, identification of biomarkers and combinatorial therapeutic strategies, have the potential to improve the efficacy and safety profiles of current immunotherapies.

关键词： CD47 PD-1 PD-L1 immunotherapy TAM phagocytosis macrophage

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Influence and related mechanism of Retn gene expression on glucose uptake in 3T3-L1 cells

LI Yahui, DONG Shiyuan, YU Chao, JIANG Yu, LI Huaixing, SUN Shuhan

《医学前沿（英文）》 2007年第1卷第3期页码 269-273 doi: 10.1007/s11684-007-0051-1

摘要： The aim of this article was to investigate the influence and the related mechanism of the gene on glucose uptake and insulin resistance in 3T3-L1 cells. Radioimmunoassay was used to determine glucose uptake in 3T3-L1 cells with different gene expression levels, whether cells were stimulated by insulin or not. RT-PCR and real-time RT-PCR analysis were used to determine the mRNA levels of several glucose transport proteins in 3T3-L1 cells with different gene expression levels, including insulin receptor substrate-1(IRS-1), phosphatidylinositol 3-kinase (PI-3K), AKT-2, glucose transporter-4 (GLUT-4), p38 mitogen-activated protein kinase (p38MAPK) and glycogen synthase kinase-3b (GSK-3). The glucose uptake decreased with the increase in gene expression in 3T3-L1 cells, which was independent of whether the cells were stimulated by insulin or not. The mRNA expression of two signal proteins PI-3K and AKT-2 decreased and the other two signal proteins, GSK-3 and p38MAPK, increased with overexpression in 3T3-L1 cells. Resistin could induce insulin resistance in adipocytes, which might be related to the changes of some proteins in PI-3K and Ras pathways.

关键词： 3T3-L1 influence resistance receptor substrate-1 transport

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解决地下通信技术难题的方案及关键设备

司徒梦天

《中国工程科学》 2001年第3卷第7期页码 64-69

摘要：

文章叙述了在地下无线电通信中的两大技术难题——弱信号接收和抗雷电脉冲干扰，提出其解决途径，并介绍解决这些技术难题的关键设备——弱信号抗雷电电报终端机的设计方案，分析该机的性能和给出实验室测试和现场试验的结果。

关键词：地下无线电通信弱信号接收抗雷电脉冲干扰

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基于世界模型与图像表示的交通信号控制 Research Article

戴星原1,2,赵宸1,2,王晓3,吕宜生1,2,林懿伦4,王飞跃1,2

《信息与电子工程前沿（英文）》 2022年第23卷第12期页码 1795-1813 doi: 10.1631/FITEE.2200323

摘要：交通信号控制正从被动控制过渡到主动控制，以引导当前交通流按预期状态运行。一个有效的预测模型对主动交通信号控制至关重要；其中预测什么交通状态，如何高精度预测，以及如何利用预测优化控制策略是主动交通信号控制研究的关键问题。本文使用车辆位置图像描述路口交通状态，同时受基于模型的强化学习方法DreamerV2的启发，引入基于学习的交通世界模型。该世界模型以图像序列描述交通动态，并作为交通环境的抽象替代以生成多步预测样本用于控制策略优化。在执行阶段，优化后的交通信号控制器根据交通状态的抽象表示直接实时输出控制指令，同时世界模型能够预测不同控制行为对未来交通状态的影响。实验结果表明，基于交通世界模型优化的控制策略的性能优于一般基准，并且世界模型实现了基于图像的高精度预测；这些结果显示了世界模型在未来交通信号控制中的应用前景。

关键词：交通信号控制；交通预测；交通世界模型；强化学习

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Analysis and stabilization control of a voltage source controlled wind farm under weak grid conditions

《能源前沿（英文）》 2022年第16卷第6期页码 943-955 doi: 10.1007/s11708-021-0793-5

摘要： This paper investigates and discusses the interaction stability issues of a wind farm with weak grid connections, where the wind turbines (WTs) are controlled by a new type of converter control strategy referred to as the voltage source (VS) control. The primary intention of the VS control method is to achieve the high-quality inertial response capability of a single WT. However, when it is applied to multiple WTs within a wind farm, its weak-grid performance regarding the stability remains concealed and needs to be clarified. To this end, a frequency domain model of the wind farm under the VS control is first developed. Based on this model and the application of a stability margin quantification index, not only the interactions between the wind farm and the weak grid but also those among WTs will be systematically assessed in this paper. A crucial finding is that the inertial response of VS control has negative impacts on the stability margin of the system, and the dominant instability mode is more related to the interactions among the WTs rather than the typical grid-wind farm interaction. Based on this knowledge, a stabilization control strategy is then proposed, aiming for stability improvements of VS control while fulfilling the demand of inertial responses. Finally, all the results are verified by time-domain simulations in power systems computer aided design/electromagnetic transients including DC(PSCAD/EMTDC).

关键词： weak grids voltage source (VS) control wind turbine (WT) stabilization control wind farm inertial response

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适用于低轨微小卫星的大视场红外地球敏感器

王昊1,王志远1,王本冬1,金仲和1,John L. CRASSIDIS2

《信息与电子工程前沿（英文）》 2021年第22卷第2期页码 141-286 doi: 10.1631/FITEE.1900358

摘要：红外地球敏感器广泛应用于卫星姿态确定和控制系统中。静态红外地球敏感器的主要缺点是视场较小，其典型视场约为20°至30°，可能不适用于近地轨道的微型卫星。设计了一种新型的小型红外地球敏感器，其视场接近180°。该地球敏感器包括全景环形透镜（PAL）和红外CMOS传感器。PAL镜头用于增强视场，从而从近地轨道获得完整的地球红外图像，据此提出一种补偿PAL引起的畸变和计算地球矢量的算法。新型红外地球敏感器结构紧凑，功耗低，精度高。利用ZDPS-2微小卫星获得在轨红外图像和模拟图像，评估新型红外地球敏感器的性能，实验表明其精度约为0.032°。

关键词：红外地球敏感器；微小卫星；姿态确定系统

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Molecular classification and precision therapy of cancer: immune checkpoint inhibitors

null

《医学前沿（英文）》 2018年第12卷第2期页码 229-235 doi: 10.1007/s11684-017-0581-0

摘要：

On May 23, 2017, the US Food and Drug Administration (FDA) approved a treatment for cancer patients with positive microsatellite instability-high (MSI-H) markers or mismatch repair deficient (dMMR) markers. This approach is the first approved tumor treatment using a common biomarker rather than specified tumor locations in the body. FDA previously approved Keytruda for treatment of several types of malignancies, such as metastatic melanoma, metastatic non-small-cell lung cancer, recurrent or metastatic head and neck cancer, refractory Hodgkin lymphoma, and urothelial carcinoma, all of which carry positive programmed death-1/programmed death-ligand 1 biomarkers. Therefore, indications of Keytruda significantly expanded. Several types of malignancies are disclosed by MSI-H status due to dMMR and characterized by increased neoantigen load, which elicits intense host immune response in tumor microenvironment, including portions of colorectal and gastric carcinomas. Currently, biomarker-based patient selection remains a challenge. Pathologists play important roles in evaluating histology and biomarker results and establishing detection methods. Taking gastric cancer as an example, its molecular classification is built on genome abnormalities, but it lacks acceptable clinical characteristics. Pathologists are expected to act as “genetic interpreters” or “genetic translators” and build a link between molecular subtypes with tumor histological features. Subsequently, by using their findings, oncologists will carry out targeted therapy based on molecular classification.

关键词： molecular classification precision medicine pembrolizumab PD-1/PD-L1 MSI-H

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Enhancement of sludge gravitational thickening with weak ultrasound

Panyue ZHANG, Tian WAN, Guangming ZHANG

《环境科学与工程前沿（英文）》 2012年第6卷第5期页码 753-760 doi: 10.1007/s11783-011-0368-5

摘要： Gravitational thickening is the prevailing method to reduce sludge volume but the process is slow and usually requires addition of polyelectrolyte(s). This paper investigated the potential benefits of sonication on enhancing the sludge gravitational thickening with very low energy dose, so called “weak ultrasound”. Results showed that weak sonication significantly changed the sludge settlability and the main mechanism was release of the loosely bounded extracellular polymeric substances. The changes in sludge behaviors by sonication were strongly influenced by power density and sonication duration. Lower sound frequency was slightly better than higher frequency. Weak sonication (<680 kJ·kg DS) improved the sludge gravitational thickening while high ultrasonic energy deteriorated the process. Considering both the sludge thickening efficiency and energy consumption, the optimum conditions were 0.15 W·mL , 7 s, and 25 kHz. Under such conditions, the energy dose was only 155 kJ·kg DS, much lower than literature reports, and the sludge settling time was shortened from 24 h to 12?h. Weak sonication could substitute expensive polyelectrolyte coagulant for sludge thickening. Combination of weak sonication and polyelectrolyte could further reduce the settling time to 6 h. The final water content of the thickened sludge was not changed after sonication or polyelectrolyte addition.

关键词： activated sludge sonication settlability dry weight extracellular polymeric substances polyelectrolyte

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of the agglomeration of crystals in the reactive crystallization of 5-(difluoromethoxy)-2-mercapto-1

Yongli WANG, Shuyuan MA, Xiaodong Lü, Chuang XIE

《化学科学与工程前沿（英文）》 2012年第6卷第4期页码 423-431 doi: 10.1007/s11705-012-1211-7

摘要： 5-(Difluoromethoxy)-2-mercapto-1 -benzimidazole (DMB) was precipitated by adding acetic acid to the DMB sodium salt solution. The spherical agglomeration of DMB during the reactive crystallization in a batch crystallizer was monitored by real-time Particle Video Microscope (PVM). We found that the low feeding rate of acetic acid, high crystallization temperature, low agitation rate or adding seed crystal can facilitate the formation of spherical agglomerates. By using a simple model, the mean crystal agglomerate size of DMB thus predicted is generally in agreement with the experimental data. In addition, the crystallization process of DMB was optimized by a new control strategy of supersaturation to avoid disadvantages brought by agglomeration.

关键词： 5-(difluoromethoxy)-2-mercapto-1H-benzimidazole (DMB) reactive crystallization agglomeration feeding rate crystallization temperature agitation rate

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Modeling and analysis of magnetic dipoles in weak magnetic field

WANG Zhaoxia, ZHANG Weimin, LIU Hongguang

《机械工程前沿（英文）》 2008年第3卷第2期页码 222-225 doi: 10.1007/s11465-008-0028-z

摘要： The magnetic leakage field distribution resulting from linear defects of a tube sample in the geomagnetic field is modeled according to the magnetic dipole theory. The formula to compute the normal component of the weak magnetic field is deduced based on the spatial distribution of the magnetic dipole. The shape and characteristics of the zero line (an important criterion for magnetic memory testing) of the normal field is analyzed under different longitudinal magnetizations. Results show that the characteristics of the zero line should be considered when the metal magnetic memory testing method is used to find and locate the defect.

关键词： geomagnetic theory important criterion magnetic leakage normal component