分类： 物理学 >> 核物理学 提交时间： 2023-06-26
摘要：Neutron computed tomography (NCT) is widely used as a noninvasive measurement technique in nuclear engineering, thermal hydraulics, and cultural heritage. The neutron source intensity of NCT is usually low and the scan time is long, resulting in a projection image containing severe noise. To reduce the scanning time and increase the image reconstruction quality, an effective reconstruction algorithm must be selected. In CT image reconstruction, the reconstruction algorithms used can be divided into three categories: analytical algorithms, iterative algorithms, and deep learning. Because the analytical algorithm requires complete projection data, it is not suitable for reconstruction in harsh environments, such as strong radiation, high temperature, and high pressure. Deep learning requires large amounts of data and complex models, which cannot be easily deployed, as well as has a high computational complexity and poor interpretability. Therefore, this paper proposes the OS-SART-PDTV iterative algorithm, which uses the ordered subset simultaneous algebraic reconstruction technique (OS-SART) algorithm to reconstruct the image and the first-order primal-dual algorithm to solve the total variation (PDTV), for sparse-view NCT three-dimensional reconstruction. The novel algorithm was compared with other algorithms (FBP, OS-SART-TV, OS-SART-AwTV, and OS-SART-FGPTV) by simulating the experimental data and actual neutron projection experiments. The reconstruction results demonstrate that the proposed algorithm outperforms the FBP, OS-SART-TV, OS-SART-AwTV, and OS-SART-FGPTV algorithms in terms of preserving edge structure, denoising, and suppressing artifacts.
分类： 核科学技术 >> 核材料与工艺技术 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要：This study investigated the impact of simulated microgravity on acute injury induced by low doses of carbon ions in male reproductive organs of mice, and determined alterations in spermatogenic function and expression levels of apoptotic factors in mice following exposure to acute irradiation after 7 days of simulated microgravity. The results demonstrated that significant reductions in spermatozoa, primary spermatocytes and spermatogonia, and increased globular cells in seminiferous tubule and pro-apoptotic proteins were observed in the group exposed to over 0.4 Gy irradiation. Collectively, the data suggest that lesions inflicted by simulated microgravity are not markedly modified by lower doses of irradiation (0.2 Gy) in mouse testis compared to the control group. However, testicular impairments were markedly evident in the group exposed to higher doses of carbon ions plus simulated microgravity, which may be due at least in part to elevated apoptosis initiated by the mitochondrial apoptosis pathway in germ cells.
分类： 核科学技术 >> 核材料与工艺技术 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要：We evaluated the protective effect of N-acetylcysteine (NAC) on immunity system irradiated by 12C6+ ion beam. Kun-Ming mice were whole-body irradiated by 12C6+ ion at doses of 0, 0.5, 1, 1.5, 2, 2.5 and 3 Gy. The results showed that in saline group, the lymphocytes DNA double-strand breaks (DSBs), maleic dialdehyde, thymocytes number in G0/G1 and apoptosis percentage increased with dose increment, and the levels of interferon-γ, glutathione, superoxide radical (SOD) and natural killer cells activity decreased with dose increment. However, there were no significant changes in NAC-treated group. The data indicated that pre-treatment with NAC could significantly remove the ROS by counteracting the glutamate, decrease excessive lipid peroxidation reaction and SOD damages, and protect DNA, lymphocytes and cytokines against irradiation.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
Chao Mi
Ming Guan
Xun Zhang
Liu Yang
Sitong Wu
Zhichao Yang
Zhiyong Guo
Jiayan Liao
Jiajia Zhou
Dayong Jin
Xiaocong Yuan
摘要：Conventional biomedical imaging modalities, including endoscopy, X-rays, and magnetic resonance, are invasive and cannot provide sufficient spatial and temporal resolutions for regular imaging of gastrointestinal (GI) tract to guide prognosis and therapy of GI diseases. Here we report a non-invasive method for optical imaging of GI tract. It is based on a new type of lanthanide-doped nanocrystal with near-infrared (NIR) excitation at 980 nm and second NIR window (NIR-IIb) (1500~1700 nm) fluorescence emission at around 1530 nm. The rational design and controlled synthesis of nanocrystals with high brightness have led to an absolute quantum yield (QY) up to 48.6%. Further benefitting from the minimized scattering through the NIR-IIb window, we enhanced the spatial resolution by 3 times compared with the other NIR-IIa (1000~1500 nm) contract agents for GI tract imaging. The approach also led to a high temporal resolution of 8 frames per second, so that the moment of mice intestinal peristalsis happened in one minute can be captured. Furthermore, with a light-sheet imaging system, we demonstrated a three-dimensional (3D) imaging of the stereoscopic structure of the GI tract. Moreover, we successfully translate these advances to diagnose inflammatory bowel disease (IBD) in a pre-clinical model of mice colitis.
分类： 地球科学 >> 地理学 提交时间： 2021-04-30 合作期刊: 《干旱区科学》
摘要：Snow avalanches are a common natural hazard in many countries with seasonally snow-covered mountains. The avalanche hazard varies with snow avalanche type in different snow climate regions and at different times. The ability to understand the characteristics of avalanche activity and hazards of different snow avalanche types is a prerequisite for improving avalanche disaster management in the mid-altitude region of the Central Tianshan Mountains. In this study, we collected data related to avalanche, snowpack, and meteorology during four snow seasons (from 2015 to 2019), and analysed the characteristics and hazards of different types of avalanches. The snow climate of the mid-altitude region of the Central Tianshan Mountains was examined using a snow climate classification scheme, and the results showed that the mountain range has a continental snow climate. To quantify the hazards of different types of avalanches and describe their situation over time in the continental snow climate region, this study used the avalanche hazard degree to assess the hazards of four types of avalanches, i.e., full-depth dry snow avalanches, full-depth wet snow avalanches, surface-layer dry snow avalanches, and surface-layer wet snow avalanches. The results indicated that surface-layer dry snow avalanches were characterized by large sizes and high release frequencies, which made them having the highest avalanche hazard degree in the Central Tianshan Mountains with a continental snow climate. The overall avalanche hazard showed a single peak pattern over time during the snow season, and the greatest hazard occurred in the second half of February when the snowpack was deep and the temperature increased. This study can help the disaster and emergency management departments rationally arrange avalanche relief resources and develop avalanche prevention strategies.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-02
Liu, Y [Liu, Yang][ 1 ]
Qin, YP [Qin, Yinping][ 1 ]
Peng, Z [Peng, Zhe][ 1 ]
Zhou, JJ [Zhou, Jingjing][ 1 ]
Wan, CJ [Wan, Changjin][ 1 ]
Wang, DY [Wang, Deyu][ 1 ]
摘要：Hexamethylene diisocyanate can chemically react with the onium ion produced by the oxidation of propylene carbonate and in situ generate a novel interfacial layer that is stable at high potential. With an appropriate thickness of this film, LiNi1/3Co1/3Mn1/3O2 presents significantly improved rate and cycle performances when tested between 2.5 and 4.6 V (vs. Li/Li+).
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-02
Bi, YJ [Bi, Yujing][ 1 ]
Yang, WC [Yang, Wenchao][ 1 ]
Du, R [Du, Rui][ 1 ]
Zhou, JJ [Zhou, Jingjing][ 1 ]
Liu, M [Liu, Meng][ 1 ]
Liu, Y [Liu, Yang][ 1 ]
Wang, DY [Wang, Deyu][ 1 ]
摘要：In this work, we investigate the influence of oxygen non-stoichiometry on the characteristics of LiNi0.8Co0.1Mn0.1O2 cathode material. Among the investigated samples, the level of Ni/Li disorder in the bulk and the thickness of auto-generated layer on the surface share the same trend as the amount of oxygen loss in LiNi0.8Co0.1Mn0.1O2 materials. It indicates that the aforementioned key structural in- stabilities should be tightly related to the oxygen defects and the induced structural relaxation. As a consequence of structural entirety, the sample with the least defects presents the highest discharge capacity (192.9 mAhg 1 at 0.1C), the best rate capability (160.1 mAhg 1 at 5C), and the most stable cyclibility (89.9% at 200th). Our results demonstrate that oxygen deficiency plays a key role to determine the electrochemical performance of high-nickel cathode materials.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-02
Peng, Z [Peng, Zhe][ 1 ]
Wang, SW [Wang, Shuwei][ 1 ]
Zhou, JJ [Zhou, Jingjing][ 1 ]
Jin, Y [Jin, Yan][ 1 ]
Liu, Y [Liu, Yang][ 1 ]
Qin, YP [Qin, Yinping][ 1 ]
Shen, C [Shen, Cai][ 1 ]
Han, WQ [Han, Weiqiang][ 1 ]
Wang, DY [Wang, Deyu][ 1 ]
摘要：A surface protective structure to efficiently improve the cyclic stability and lifetime of the lithium metal electrode is investigated. By volu- metrically confining plated lithium metal in the inter-space of a ceramic porous layer and isolating the confined lithium via a rein- forced skin-layer from attack by electrolyte solvents, the coulombic efficiency of the protected lithium metal electrode reaches very high values of $97–99%.
提交时间： 2017-05-02
Wan, CJ [Wan, Chang Jin][ 1,2,3 ]
Zhu, LQ [Zhu, Li Qiang][ 3 ]
Liu, YH [Liu, Yang Hui][ 3 ]
Feng, P [Feng, Ping][ 1,2 ]
Liu, ZP [Liu, Zhao Ping][ 3 ]
Cao, HL [Cao, Hai Liang][ 3 ]
Xiao, P [Xiao, Peng][ 3 ]
Shi, Y [Shi, Yi][ 1,2 ]
Wan, Q [Wan, Qing][ 1,2,3 ]
摘要：Proton-conducting graphene oxide electrolyte films with very high electric-double-layer capacitance are used as the gate dielectrics for oxide-based neuron transistor fabrication. Paired-pulse facilitation, dendritic integration, and orientation tuning ar
分类： 生物学 >> 生物物理学 >> 细胞生物学 提交时间： 2016-05-11
Zhu, Lei
Yang, Jing-Yu
Dong, Ying-Xu
Liu, Yang
Miao, Feng-Rong
Xue, Hong
Wu, Chun-Fu
Xue, Hong
Xue, Xue
Wang, Yong-Feng
摘要：In Alzheimer's disease (AD), activated microglia invade and surround beta-amyloid plaques, possibly contributing to the aggregation of amyloid beta (A beta), which affect the survival of neurons and lead to memory loss. Phosphodiesterase-5 (PDE-5) inhibitors have recently been shown a potential therapeutic effect on AD. In this study, the effects of yonkenafil (yonk), a novel PDE-5 inhibitor, on cognitive behaviors as well as the pathological features in transgenic AD mice were investigated. Seven-month-old APP/PSI transgenic mice were treated with yonk (2, 6, or 18 mg/kg, intraperitoneal injection (i.p.)) or sildenafil (slid) (6 mg/kg, i.p.) daily for 3 months and then behavioral tests were performed. The results demonstrated that yonk improved nesting-building ability, ameliorated working memory deficits in the Y-maze tasks, and significantly improved learning and memory function in the Morris water maze (MWM) tasks. In addition, yonk reduced the area of A beta plaques, and inhibited over-activation of microglia and astrocytes. Furthermore, yonk increased neurogenesis in the dentate granule brain region of APP/PSI mice, indicated by increased BrdU(+)/NeuN(+) and BrdU(+)/DCX+ cells compared to vehicle-treated transgenic mice. These results suggest that yonk could rescue cognitive deficits by ameliorated amyloid burden through regulating APP processing, inhibited the over-activation of microglia and astrocytes as well as restored neurogenesis. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
分类： 生物学 >> 生物物理学 提交时间： 2016-05-11
Duan, Demin
Fan, Kelong
Zhang, Dexi
Zhang, Jianlin
Yan, Xiyun
Tan, Shuguang
Gao, George Fu
Liang, Mifang
Liu, Yang
Zhang, Panhe
Liu, Wei
Qiu, Xiangguo
Kobinger, Gary P.
Gao, George Fu
摘要：Ebola continues to rage in West Africa. In the absence of an approved vaccine or treatment, the priority in controlling this epidemic is to promptly identify and isolate infected individuals. To this end, a rapid, highly sensitive, and easy-to-use test for Ebola diagnosis is urgently needed. Here, by using Fe3O4 magnetic nanoparticle (MNP) as a nanozyme probe, we developed a MNP-based immunochromatographic strip (Nanozyme-strip), which detects the glycoprotein of Ebola virus (EBOV) as low as 1 ng/mL, which is 100-fold more sensitive than the standard strip method. The sensitivity of the Nanozyme-strip for EBOV detection and diagnostic accuracy for New Bunyavirus clinical samples is comparable with ELISA, but is much faster (within 30 min) and simpler (without need of specialist facilities). The results demonstrate that the Nanozyme-strip test can rapidly and sensitively detect EBOV, providing a valuable simple screening tool for diagnosis of infection in Ebola-stricken areas. (C) 2015 Elsevier B.V. All rights reserved.
分类： 生物学 >> 生物物理学 提交时间： 2016-05-11
Wang, Lizhong
Liu, Runhua
Ye, Peiying
Wong, Chunshu
Chen, Guo-Yun
Sakabe, Kaoru
Jube, Sandro
Zheng, Pan
Liu, Yang
Ye, Peiying
Wong, Chunshu
Chen, Guo-Yun
Sakabe, Kaoru
Jube, Sandro
Zheng, Pan
Liu, Yang
Ye, Peiying
Zhou, Penghui
Zheng, Xincheng
Wu, Wei
摘要：CD24 is overexpressed in nearly 70% human cancers, whereas TP53 is the most frequently mutated tumour-suppressor gene that functions in a context-dependent manner. Here we show that both targeted mutation and short hairpin RNA (shRNA) silencing of CD24 retard the growth, progression and metastasis of prostate cancer. CD24 competitively inhibits ARF binding to NPM, resulting in decreased ARF, increase MDM2 and decrease levels of p53 and the p53 target p21/CDKN1A. CD24 silencing prevents functional inactivation of p53 by both somatic mutation and viral oncogenes, including the SV40 large T antigen and human papilloma virus 16 E6-antigen. In support of the functional interaction between CD24 and p53, in silico analyses reveal that TP53 mutates at a higher rate among glioma and prostate cancer samples with higher CD24 mRNA levels. These data provide a general mechanism for functional inactivation of ARF and reveal an important cellular context for genetic and viral inactivation of TP53.
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