Subjects: Digital Publishing >> New Media submitted time 2023-10-08 Cooperative journals: 《中国传媒科技》
Abstract：音频媒体在中国共产党百年传播事业中意义非凡,梳理其进阶史是应有之义。文章尝试以科技为切入口,为其理出发展分期。20世纪20年代,广播电台问世,制作与传播技术几经变革,不变的是其始终扮演着党群联系的纽带、知识教化的载体、文化传播的桥梁等角色。20世纪末期,网络音频兴起,其社交属性贴合用户需求,跨终端传输提升效率,"视频化"延伸音频样态,AoIP技术改善广播模式,数字信号广播逐渐发展成数字多媒体广播,车载网络音频逐渐普及并成为收听主阵地。21世纪,智能音频凸显优势,机器基于深度学习赋能声音传播,车载音频系统日渐开放式与场景化,5G技术加速智能音频多领域传播。智能音频的易用是首要标准,内容是制胜之道,伴随是根本需要,分发是关键法宝。然而,智能音频可能造成的信息茧房、隐私泄露等问题仍需引起警觉。
Subjects: Psychology >> Social Psychology submitted time 2023-03-27 Cooperative journals: 《心理学报》
Abstract： Early life stress (ELS) has been used to describe a broad spectrum of adverse and stressful events, including childhood trauma occurring during neonatal life, early and late childhood, and adolescence. Childhood is a vulnerable time point for stressful events due to an immature brain, which increases the risk of psychopathology in later life. However, to date, studies have focused almost exclusively on adolescents and adults, and little is known about the relationship between ELS and the structural and functional brain changes in children. Here, we adopted a multimodal approach combining voxel-based morphometry (VBM) and functional connectivity (FC) to examine the neural substrates of ELS in children aged 9~12 years.A total of 139 children were recruited for this study. For each participant, the ELS level was assessed and an 8-minute rs-fMRI scan was performed using a 3T Trio scanner. Participants with unqualified data were excluded, resulting in a final sample of 78 participants (39 females; mean age = 10.18). For statistical analysis, we used the gray matter volume (GMV) and FC to explore the brain structural and functional correlates of children’s ELS and then used a machine learning method to investigate whether and how structural connectivity profiles in predefined brain networks can predict ELS levels. Additionally, exploratory analyses were performed to investigate potential sex differences and age characteristics in GMV and FC associated with children’s ELS. VBM analysis showed that greater ELS was associated with a larger GMV in the left medial orbitofrontal cortex, right insular cortex, left superior temporal gyrus, and left supplementary motor area. Subsequently, we used these clusters as seed regions to analyze the correlation between FC and stress in children. We found that greater ELS was associated with lower insular-inferior parietal lobule (IPL) connectivity. The results were not influenced by sex, age, total intracranial volume, or head motion. Furthermore, the predictive analysis of machine learning reported that the sensorimotor, frontoparietal, salience, visual, and cerebellar networks could marginally predict ELS scores. Finally, exploratory analyses showed that there were no significant sex differences in the GMV or FC associated with ELS and that significant correlations of ELS with the GMV of the inferior occipital gyrus were mainly manifested in 9-year-old children. Using VBM and FC analyses, we detected structural and functional brain alterations associated with ELS in children aged 9~12 years. Specifically, the VBM analysis mainly reflected that children with high ELS may have abnormal emotional and cognitive functions, such as hypersensitivity to emotional stimuli and over-monitoring of their own behavior. In addition, FC analysis indicated that aberrant interaction of internal and external information may contribute to high ELS in childhood. This study not only provides unique insights into the neural substrates of ELS but may also help identify children who are susceptible to ELS within the general population, which may be advantageous for early prevention strategies and interventions for children.
Subjects: Psychology >> Other Disciplines of Psychology submitted time 2022-09-08
Abstract：
Early life stress (ELS) has been used to describe a broad spectrum of adverse and stressful events, including childhood trauma occurring during neonatal life, early and late childhood, and adolescence. Childhood is a vulnerable time point for stressful events due to an immature brain, which increases the risk of psychopathology in later life. However, to date, studies have focused almost exclusively on adolescents and adults, and little is known about the relationship between ELS and the structural and functional brain changes in children. Here, we adopted a multimodal approach combining voxel-based morphometry (VBM) and functional connectivity (FC) to examine the neural substrates of ELS in children aged 9~12 years.
A total of 139 children were recruited for this study. For each participant, the ELS level was assessed and an 8-minute rs-fMRI scan was performed using a 3T Trio scanner. Participants with unqualified data were excluded, resulting in a final sample of 78 participants (39 females; mean age = 10.18). For statistical analysis, we used the gray matter volume (GMV) and FC to explore the brain structural and functional correlates of children’s ELS and then used a machine learning method to investigate whether and how structural connectivity profiles in predefined brain networks can predict ELS levels. Additionally, exploratory analyses were performed to investigate potential sex differences and age characteristics in GMV and FC associated with children’s ELS.
VBM analysis showed that greater ELS was associated with a larger GMV in the left medial orbitofrontal cortex, right insular cortex, left superior temporal gyrus, and left supplementary motor area. Subsequently, we used these clusters as seed regions to analyze the correlation between FC and stress in children. We found that greater ELS was associated with lower insular-inferior parietal lobule (IPL) connectivity. The results were not influenced by sex, age, total intracranial volume, or head motion. Furthermore, the predictive analysis of machine learning reported that the sensorimotor, frontoparietal, salience, visual, and cerebellar networks could marginally predict ELS scores. Finally, exploratory analyses showed that there were no significant sex differences in the GMV or FC associated with ELS and that significant correlations of ELS with the GMV of the inferior occipital gyrus were mainly manifested in 9-year-old children.
Using VBM and FC analyses, we detected structural and functional brain alterations associated with ELS in children aged 9~12 years. Specifically, the VBM analysis mainly reflected that children with high ELS may have abnormal emotional and cognitive functions, such as hypersensitivity to emotional stimuli and over-monitoring of their own behavior. In addition, FC analysis indicated that aberrant interaction of internal and external information may contribute to high ELS in childhood. This study not only provides unique insights into the neural substrates of ELS but may also help identify children who are susceptible to ELS within the general population, which may be advantageous for early prevention strategies and interventions for children.
Peer Review Status:
Awaiting Review
Subjects: Biology >> Botany >> Applied botany submitted time 2021-12-19 Cooperative journals: 《广西植物》
Abstract： To clarify the anti-melanoma active extract and material basis of Veronica didyma Tenore, CCK8 method was used to evaluate the inhibitory effects of four extracts (petroleum ether extract, ethyl acetate extract, n-butanol extract, water extract), ethanol extract and monomer compounds on the proliferation of melanoma cell lines (B16 and A375); The chemical constituents of the active fraction were systematically separated and purified by phytochemical techniques and methods. The results were as follows: (1) Ethyl acetate extract (PPNE) had better inhibitory effect on the proliferation of B16 and A375 cells than other samples, and IC50 = 0.177 mg·mL-1 (B16), IC50 = 2.826 mg·mL-1 (A375), respectively. Seven monomers were obtained from PPNE were p-hydroxybenzaldehyde (1), Picroside II (2), isoscutellarein 7 - O - (6''' - Oacetyl) - β - allopyranosyl (1'''→2'') - β - glucopyranoside (3), 3' - hydroxyl - 4' - O - methylisoscutellarein 7 - O - [6''' - O - acetyl - β - D - allopyranosyl - (1→2) - β - D - Glucopyranoside (4), 6 - O - veratroylcatalposide (5), Veronicoside (6), isoscutellarein 4' - methyl ether 7 - O - (6''' - O - acetyl) - ballopyranosyl (1'''→2'') - β - glucopyranoside (7). (2) Seven compounds were isolated from this plant for the first time, and HPLC showed that these seven compounds are the major components of PPNE. Except Compound 1, the other six monomers all have good inhibitory effect on the proliferation of melanoma cells, and the anti-melanoma activities of compounds 3, 4 and 7 are reported for the first time. Based on these results, PPNE of Veronica didyma Tenore is an anti melanoma active fraction, Iridoids (compounds 2, 5, 6) and flavonoids (compounds 3, 4, 7) may be the basis of anti melanoma activity of PPNE. The results of this study will lay scientific foundation for the rational use of Veronica didyma Tenore sresources.
Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2019-03-05 Cooperative journals: 《电气工程学报》
Abstract：为对建筑物防雷系统中分支导体在雷电流作用下的温升进行估算，提出了 两种计算导体温升的数学模型。该模型用于估算在假设电流密度均匀分布在导体横截 面内以及考虑到暂态趋肤效应下电流密度非均匀分布两种情况下圆柱导体的温升。根 据以上两种数学模型，分别估算出了分支导体 3 在不同雷电流幅值作用下的温升：幅 值为 100kA 时，其温升分别为 2.25℃和 2.75℃；当幅值为 150kA 时，其温升分别为 5.1℃和 6.18℃；当幅值为 200kA 时，其温升分别为 9.19℃和 11℃。本文还验证了该 数学模型的研究结果。分析表明：文献中给出的测量数据与该模型计算得出的数据基 本一致；防雷系统中各分支导体的温升确实会受到暂态趋肤效应的影响；该部分引起 的导体额外温度上升很小可以忽略不计。
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-05-24 Cooperative journals: 《工程热物理学报》
Abstract：本文对液氦温区Vuilleumier耦合脉冲管(VM-PT)制冷机进行了数值计算研究。为了减小来自室温的漏热，将气库置于一级冷头之上。采用SAGE软件建立了数值计算模型，以无负荷制冷温度为目标函数对制冷机运行参数进行了优化。为了进一步了解制冷机的工作原理，研究了脉冲管制冷机内焓流、声功、熵流、压力波、体积流率及温度的沿程分布，并对其相位关系和可用能损失进行了分析。计算结果表明，该制冷机可在平均压力0.9 MPa、压比1.61、运行频率0.8 Hz时得到3.69 K的无负荷制冷温度，在4.2 K时可提供16.24 mW制冷量。
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