背景:阿尔茨海默病病因多样且发病机制复杂,至今尚未完全阐明。近年来,非编码RNA被证实在调控β-淀粉样蛋白异常沉积、Tau蛋白过度磷酸化、神经炎症激活、线粒体功能障碍及突触损伤等过程中发挥关键作用,为阐释疾病机制和药物研发提供...背景:阿尔茨海默病病因多样且发病机制复杂,至今尚未完全阐明。近年来,非编码RNA被证实在调控β-淀粉样蛋白异常沉积、Tau蛋白过度磷酸化、神经炎症激活、线粒体功能障碍及突触损伤等过程中发挥关键作用,为阐释疾病机制和药物研发提供了新视角。同时,中医药通过调控非编码RNA网络展现了多通路干预优势。目的:综述近年来调节性非编码RNA和转运RNA在阿尔茨海默病病理机制中的相关研究,总结中药单体、复方及针灸调控不同非编码RNA发挥抗阿尔茨海默病的现状,以期为今后阿尔茨海默病临床治疗策略优化及新型药物研发提供理论依据与方向参考。方法:以“非编码RNA、微小RNA、长链非编码RNA、环状RNA、转运RNA、阿尔茨海默病、中医药”为中文检索词,以“ncRNA,miRNA,lncRNA,circRNA,tRNA,Alzheimer’s disease,traditional Chinese Medicine”为英文检索词,检索中国知网和PubMed数据库2015年1月至2025年7月发表的相关文献,根据纳入及排除标准最终纳入101篇文献进行综述分析。结果与结论:①阿尔茨海默病的发生与发展源于一个多因素相互关联的病理网络,主要包括β-淀粉样蛋白沉积、Tau蛋白过度磷酸化、神经炎症激活、线粒体功能障碍、氧化应激、突触结构与功能异常以及钙稳态失衡等关键机制,这些因素之间亦可彼此交织、协同促进疾病进程;②多种调节性非编码RNA如微小RNA、长链非编码RNA、环状RNA以及管家非编码RNA中的转运RNA可通过不同层面调控上述病理过程,进而影响疾病进展;③诸多中药单体活性成分如小檗碱、梓醇、三七总皂苷、人参皂苷Rg1、β-细辛醚、雷公藤内酯醇、丹参酮IIA;中药复方如安神定志方、调心方、补肾填髓方以及针刺和艾灸等中医疗法均能通过上调或下调特定非编码RNA的表达,干预阿尔茨海默病的多个病理环节,发挥神经保护作用,从而延缓疾病的发生与发展。展开更多
In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC compon...In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC component code. Firstly, the sub-channel capacities of MLCM systems is analyzed and discussed, based on which the optimal component code rate can be obtained. Secondly, an extrinsic information transfer chart based two-stage searching algorithm is proposed to find the good irregular QC-LDPC code ensembles with optimal component code rates for their corresponding sub-channels. Finally, by constructing the irregular QC-LDPC component codes from the designed ensembles with the aim of possibly enlarging the girth and reducing the number of the shortest cycles, the designed irregular QC-LDPC code based 16QAM and 64QAM MLCM systems can achieve 0.4 dB and 1.2 dB net coding gain, respectively, compared with the recently proposed regular QC-LDPC code based 16QAM and 64QAM MLCM systems.展开更多
Steam–gas pressurizers are self-pressurizing, and since steam and noncondensable gas are used to sustain their pressure, they experience very complicated thermal–hydraulic phenomena owing to the presence of the latt...Steam–gas pressurizers are self-pressurizing, and since steam and noncondensable gas are used to sustain their pressure, they experience very complicated thermal–hydraulic phenomena owing to the presence of the latter. A steam–gas pressurizer model was developed using Relap5 code to investigate such a pressurizer's thermal–hydraulic characteristics.The important thermal–hydraulic processes occurring in the pressurizer model include bulk flashing, rainout, wall condensation with noncondensable gas, and interfacial heat and mass transfer. The pressurizer model was verified using results from insurge experiments performed at the Massachusetts Institute of Technology. It was found that noncondensable gas was one of the important factors governing the pressure response, and the accuracy of the developed model would change with different mass fractions and types of noncondensable gas.展开更多
This paper investigates the simultaneous wireless information and powertransfer(SWIPT) for network-coded two-way relay network from an information-theoretic perspective, where two sources exchange information via an S...This paper investigates the simultaneous wireless information and powertransfer(SWIPT) for network-coded two-way relay network from an information-theoretic perspective, where two sources exchange information via an SWIPT-aware energy harvesting(EH) relay. We present a power splitting(PS)-based two-way relaying(PS-TWR) protocol by employing the PS receiver architecture. To explore the system sum rate limit with data rate fairness, an optimization problem under total power constraint is formulated. Then, some explicit solutions are derived for the problem. Numerical results show that due to the path loss effect on energy transfer, with the same total available power, PS-TWR losses some system performance compared with traditional non-EH two-way relaying, where at relatively low and relatively high signalto-noise ratio(SNR), the performance loss is relatively small. Another observation is that, in relatively high SNR regime, PS-TWR outperforms time switching-based two-way relaying(TS-TWR) while in relatively low SNR regime TS-TWR outperforms PS-TWR. It is also shown that with individual available power at the two sources, PS-TWR outperforms TS-TWR in both relatively low and high SNR regimes.展开更多
The Q-ary low-density parity-check（LDPC） coded high order partial response continuous phase modulation（PR-CPM） with double iterative loops is investigated. This scheme shows significant improvements in power and b...The Q-ary low-density parity-check（LDPC） coded high order partial response continuous phase modulation（PR-CPM） with double iterative loops is investigated. This scheme shows significant improvements in power and bandwidth efficiency, but at the expense of long iterative decoding delay and computational complexity induced by the improper match between the demodulator and the decoder. To address this issue, the convergence behavior of Q-ary LDPC coded CPM is investigated for the Q=2 and Q〉2 cases, and an optimized design method based on the extrinsic information transfer chart is proposed to improve the systematic iterative efficiency. Simulation results demonstrate that the proposed method can achieve a perfect tradeoff between iterative decoding delay and bit error rate performance to satisfy real-time applications.展开更多
In this paper, the Multiple Input Multiple Output (MIMO) doubly-iterative receiver which consists of the Probabilistic Data Association detector (PDA) and Low-Density Parity-Check Code (LDPC) decoder is developed. The...In this paper, the Multiple Input Multiple Output (MIMO) doubly-iterative receiver which consists of the Probabilistic Data Association detector (PDA) and Low-Density Parity-Check Code (LDPC) decoder is developed. The receiver performs two iterative decoding loops. In the outer loop, the soft information is exchanged between the PDA detector and the LDPC decoder. In the inner loop, it is exchanged between variable node and check node decoders inside the LDPC decoder. On the light of the Extrinsic Information Transfer (EXIT) chart technique, an LDPC code degree profile optimization algorithm is developed for the doubly-iterative receiver. Simulation results show the doubly-receiver with optimized irregular LDPC code can have a better performance than the one with the regular one.展开更多
文摘背景:阿尔茨海默病病因多样且发病机制复杂,至今尚未完全阐明。近年来,非编码RNA被证实在调控β-淀粉样蛋白异常沉积、Tau蛋白过度磷酸化、神经炎症激活、线粒体功能障碍及突触损伤等过程中发挥关键作用,为阐释疾病机制和药物研发提供了新视角。同时,中医药通过调控非编码RNA网络展现了多通路干预优势。目的:综述近年来调节性非编码RNA和转运RNA在阿尔茨海默病病理机制中的相关研究,总结中药单体、复方及针灸调控不同非编码RNA发挥抗阿尔茨海默病的现状,以期为今后阿尔茨海默病临床治疗策略优化及新型药物研发提供理论依据与方向参考。方法:以“非编码RNA、微小RNA、长链非编码RNA、环状RNA、转运RNA、阿尔茨海默病、中医药”为中文检索词,以“ncRNA,miRNA,lncRNA,circRNA,tRNA,Alzheimer’s disease,traditional Chinese Medicine”为英文检索词,检索中国知网和PubMed数据库2015年1月至2025年7月发表的相关文献,根据纳入及排除标准最终纳入101篇文献进行综述分析。结果与结论:①阿尔茨海默病的发生与发展源于一个多因素相互关联的病理网络,主要包括β-淀粉样蛋白沉积、Tau蛋白过度磷酸化、神经炎症激活、线粒体功能障碍、氧化应激、突触结构与功能异常以及钙稳态失衡等关键机制,这些因素之间亦可彼此交织、协同促进疾病进程;②多种调节性非编码RNA如微小RNA、长链非编码RNA、环状RNA以及管家非编码RNA中的转运RNA可通过不同层面调控上述病理过程,进而影响疾病进展;③诸多中药单体活性成分如小檗碱、梓醇、三七总皂苷、人参皂苷Rg1、β-细辛醚、雷公藤内酯醇、丹参酮IIA;中药复方如安神定志方、调心方、补肾填髓方以及针刺和艾灸等中医疗法均能通过上调或下调特定非编码RNA的表达,干预阿尔茨海默病的多个病理环节,发挥神经保护作用,从而延缓疾病的发生与发展。
基金supported by National Natural Science Foundation of China(No.61571061)
文摘In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC component code. Firstly, the sub-channel capacities of MLCM systems is analyzed and discussed, based on which the optimal component code rate can be obtained. Secondly, an extrinsic information transfer chart based two-stage searching algorithm is proposed to find the good irregular QC-LDPC code ensembles with optimal component code rates for their corresponding sub-channels. Finally, by constructing the irregular QC-LDPC component codes from the designed ensembles with the aim of possibly enlarging the girth and reducing the number of the shortest cycles, the designed irregular QC-LDPC code based 16QAM and 64QAM MLCM systems can achieve 0.4 dB and 1.2 dB net coding gain, respectively, compared with the recently proposed regular QC-LDPC code based 16QAM and 64QAM MLCM systems.
文摘Steam–gas pressurizers are self-pressurizing, and since steam and noncondensable gas are used to sustain their pressure, they experience very complicated thermal–hydraulic phenomena owing to the presence of the latter. A steam–gas pressurizer model was developed using Relap5 code to investigate such a pressurizer's thermal–hydraulic characteristics.The important thermal–hydraulic processes occurring in the pressurizer model include bulk flashing, rainout, wall condensation with noncondensable gas, and interfacial heat and mass transfer. The pressurizer model was verified using results from insurge experiments performed at the Massachusetts Institute of Technology. It was found that noncondensable gas was one of the important factors governing the pressure response, and the accuracy of the developed model would change with different mass fractions and types of noncondensable gas.
基金supported by the National Natural Science Foundation of China ( No . 61602034 )the Beijing Natural Science Foundation (No. 4162049)+2 种基金the Open Research Fund of National Mobile Communications Research Laboratory,Southeast University (No. 2014D03)the Fundamental Research Funds for the Central Universities Beijing Jiaotong University (No. 2016JBM015)the NationalHigh Technology Research and Development Program of China (863 Program) (No. 2015AA015702)
文摘This paper investigates the simultaneous wireless information and powertransfer(SWIPT) for network-coded two-way relay network from an information-theoretic perspective, where two sources exchange information via an SWIPT-aware energy harvesting(EH) relay. We present a power splitting(PS)-based two-way relaying(PS-TWR) protocol by employing the PS receiver architecture. To explore the system sum rate limit with data rate fairness, an optimization problem under total power constraint is formulated. Then, some explicit solutions are derived for the problem. Numerical results show that due to the path loss effect on energy transfer, with the same total available power, PS-TWR losses some system performance compared with traditional non-EH two-way relaying, where at relatively low and relatively high signalto-noise ratio(SNR), the performance loss is relatively small. Another observation is that, in relatively high SNR regime, PS-TWR outperforms time switching-based two-way relaying(TS-TWR) while in relatively low SNR regime TS-TWR outperforms PS-TWR. It is also shown that with individual available power at the two sources, PS-TWR outperforms TS-TWR in both relatively low and high SNR regimes.
基金supported by the National Natural Science Foundation of China(61403093)the Science Foundation of Heilongjiang Province of China for Returned Scholars(LC2013C22)the Assisted Project by Heilongjiang Province of China Postdoctoral Funds for Scientific Research Initiation(LBH-Q14048)
文摘The Q-ary low-density parity-check（LDPC） coded high order partial response continuous phase modulation（PR-CPM） with double iterative loops is investigated. This scheme shows significant improvements in power and bandwidth efficiency, but at the expense of long iterative decoding delay and computational complexity induced by the improper match between the demodulator and the decoder. To address this issue, the convergence behavior of Q-ary LDPC coded CPM is investigated for the Q=2 and Q〉2 cases, and an optimized design method based on the extrinsic information transfer chart is proposed to improve the systematic iterative efficiency. Simulation results demonstrate that the proposed method can achieve a perfect tradeoff between iterative decoding delay and bit error rate performance to satisfy real-time applications.
基金Supported by the National Natural Science Foundation of China (No. 60772061)Science Foundation of Nanjing University of Posts and Telecommunications (No. NY207132)
文摘In this paper, the Multiple Input Multiple Output (MIMO) doubly-iterative receiver which consists of the Probabilistic Data Association detector (PDA) and Low-Density Parity-Check Code (LDPC) decoder is developed. The receiver performs two iterative decoding loops. In the outer loop, the soft information is exchanged between the PDA detector and the LDPC decoder. In the inner loop, it is exchanged between variable node and check node decoders inside the LDPC decoder. On the light of the Extrinsic Information Transfer (EXIT) chart technique, an LDPC code degree profile optimization algorithm is developed for the doubly-iterative receiver. Simulation results show the doubly-receiver with optimized irregular LDPC code can have a better performance than the one with the regular one.
