89 research outputs found

    Melatonin enhances the anti-tumor effect of fisetin by inhibiting COX-2/iNOS and NF-κB/p300 signaling pathways.

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    Melatonin is a hormone identified in plants and pineal glands of mammals and possesses diverse physiological functions. Fisetin is a bio-flavonoid widely found in plants and exerts antitumor activity in several types of human cancers. However, the combinational effect of melatonin and fisetin on antitumor activity, especially in melanoma treatment, remains unclear. Here, we tested the hypothesis that melatonin could enhance the antitumor activity of fisetin in melanoma cells and identified the underlying molecular mechanisms. The combinational treatment of melanoma cells with fisetin and melatonin significantly enhanced the inhibitions of cell viability, cell migration and clone formation, and the induction of apoptosis when compared with the treatment of fisetin alone. Moreover, such enhancement of antitumor effect by melatonin was found to be mediated through the modulation of the multiply signaling pathways in melanoma cells. The combinational treatment of fisetin with melatonin increased the cleavage of PARP proteins, triggered more release of cytochrome-c from the mitochondrial inter-membrane, enhanced the inhibition of COX-2 and iNOS expression, repressed the nuclear localization of p300 and NF-κB proteins, and abrogated the binding of NF-κB on COX-2 promoter. Thus, these results demonstrated that melatonin potentiated the anti-tumor effect of fisetin in melanoma cells by activating cytochrome-c-dependent apoptotic pathway and inhibiting COX-2/iNOS and NF-κB/p300 signaling pathways, and our study suggests the potential of such a combinational treatment of natural products in melanoma therapy

    Design and research of intelligent QA system for flight crew operating manual

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    Aviation flight crews rely on a large number of complex standard documents and operation manuals when performing flight tasks. In order to relieve the pressure of manual retrieval of documents, intelligent question-answering technology based on reading comprehension is gradually applied. In this paper, the flight crew operation manual SQuAD dataset is studied and built, based on which the reader-retriever framework of text content-based reading question answering system (TCQA) is analyzed and established. Experiments are conducted to compare the relevant indexes of the QA system with different combinations of reader and retriever models under the open-source tool haystack. Based on the comparison of response speed and retrieval capability, the best model combination is obtained for the flight crew operation manual dataset, and suggestions are made for the model-related performance improvement

    Ku80 cooperates with CBP to promote COX-2 expression and tumor growth.

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    Cyclooxygenase-2 (COX-2) plays an important role in lung cancer development and progression. Using streptavidin-agarose pulldown and proteomics assay, we identified and validated Ku80, a dimer of Ku participating in the repair of broken DNA double strands, as a new binding protein of the COX-2 gene promoter. Overexpression of Ku80 up-regulated COX-2 promoter activation and COX-2 expression in lung cancer cells. Silencing of Ku80 by siRNA down-regulated COX-2 expression and inhibited tumor cell growth in vitro and in a xenograft mouse model. Ku80 knockdown suppressed phosphorylation of ERK, resulting in an inactivation of the MAPK pathway. Moreover, CBP, a transcription co-activator, interacted with and acetylated Ku80 to co-regulate the activation of COX-2 promoter. Overexpression of CBP increased Ku80 acetylation, thereby promoting COX-2 expression and cell growth. Suppression of CBP by a CBP-specific inhibitor or siRNA inhibited COX-2 expression as well as tumor cell growth. Tissue microarray immunohistochemical analysis of lung adenocarcinomas revealed a strong positive correlation between levels of Ku80 and COX-2 and clinicopathologic variables. Overexpression of Ku80 was associated with poor prognosis in patients with lung cancers. We conclude that Ku80 promotes COX-2 expression and tumor growth and is a potential therapeutic target in lung cancer

    Efficacy and safety of triazavirin therapy for coronavirus disease 2019 : A pilot randomized controlled trial

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    Acknowledgements: We are deeply grateful to the front-line clinicians who participated in the study while directly fighting the epidemic. This study was supported by the Chinese Academy of Engineering Projects for COVID-19 (2020-KYGG-01-04) and Heilongjiang Province Urgent Project-6 for COVID-19. Data and safety monitoring board members of this trial included Kang Li, Yong Zhang, Songjiang Liu, and Yaohui Shi.Peer reviewedPublisher PD

    Radiated tumor cell-derived microparticles effectively kill stem-like tumor cells by increasing reactive oxygen species

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    Stem-like tumor cells (SLTCs) are thought to be the cellular entity responsible for clinical recurrence and subsequent metastasis. Inhibiting or killing SLTCs can effectively reduce recurrence and metastasis, yet little has been done to clear SLTCs because they are usually resistant to chemotherapy, radiotherapy, and even immunotherapy. In this study, we established SLTCs by low-serum culture and confirmed that the low-serum-cultured tumor cells were in a quiescent state and resistant to chemotherapy, showing features of SLTCs, consistent with the reported data. We demonstrated that SLTCs had high levels of reactive oxygen species (ROS). Based on the finding that radiated tumor cell-derived microparticles (RT-MPs) contained ROS, we used RT-MPs to kill SLTCs. We found that RT-MPs could further increase ROS levels and kill SLTCs in vivo and in vitro partially by ROS carried by the RT-MPs themselves, providing a new method for eliminating SLTCs

    Novel Genetic Risk and Metabolic Signatures of Insulin Signaling and Androgenesis in the Anovulation of Polycystic Ovary Syndrome

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    Funding Information: The authors are grateful to all staff in the PCOSAct group for their effort in the collection of blood samples and clinical dataset which used in current study. Special thanks to Prof. Attila Toth from Institute of Physiological Chemistry, Dresden, Germany for the REC114 antibody. This study was supported by the National key Research and Development Program of China (2019YFC1709500); the National Collaboration Project of Critical Illness by Integrating Chinese Medicine and Western Medicine; the Project of Heilongjiang Province Innovation Team “TouYan;” the Yi-Xun Liu and Xiao-Ke Wu Academician Workstation; the Innovation Team of Reproductive Technique with Integrative Chinese Medicine and Western Medicine in Xuzhou City, China; Heilongjiang University of Chinese Medicine from the National Clinical Trial Base; Heilongjiang Provincial Clinical Research Center for Ovary Diseases; the Research Grant Council (T13-602/21-N, C5045-20EF, and 14122021); and Food and Health Bureau in Hong Kong, China (06171026). Ben Willem J. Mol is supported by a National Health and Medical Research Council (NHMRC) Investigator grant (GNT1176437). Ben Willem J. Mol reports consultancy for ObsEva and Merck and travel support from Merck. Xiaoke Wu, Yongyong Shi, and Chi Chiu Wang developed the research question and designed the study. Xiaoke Wu, Yongyong Shi, Yijuan Cao, and Chi Chiu Wang designed the analysis. Yongyong Shi and Zhiqiang Li contributed to the design of the experiment of whole-exome plus targeted SNP sequencing and the analysis, and interpreted the results. Jingshu Gao, Hui Chang, Duojia Zhang, Jing Cong, Yu Wang, Qi Wu, Xiaoxiao Han, Pui Wah Jacqueline Chung, Yiran Li, and Lin Zeng contributed to the experiment of metabolic profile and immunofluorescent staining and the analysis, and interpreted the results. Astrid Borchert and Hartmut Kuhn provided antibody support and advice. Xu Zheng and Lingxi Chen contributed to create the predictive model with deep machine learning. Jian Li, Qi Wu, Hongli Ma, Xu Zheng, and Lingxi Chen contributed to the analysis of the clinical characteristics and interpreted the results. Jian Li, Hongli Ma, Hui Chang, Jing Cong, and Chi Chiu Wang drafted the manuscript. All authors reviewed and revised the manuscript. Xiaoke Wu is the guarantor of this work and, as such, had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Xiaoke Wu, Chi Chiu Wang, Yijuan Cao, Jian Li, Zhiqiang Li, Hongli Ma, Jingshu Gao, Hui Chang, Duojia Zhang, Jing Cong, Yu Wang, Qi Wu, Xiaoxiao Han, Pui Wah Jacqueline Chung, Yiran Li, Xu Zheng, Lingxi Chen, Lin Zeng, Astrid Borchert, Hartmut Kuhn, Zijiang Chen, Ernest Hung Yu Ng, Elisabet Stener-Victorin, Heping Zhang, Richard S. Legro, Ben Willem J. Mol, and Yongyong Shi declare that they have no conflict of interest or financial conflicts to disclose. Funding Information: This study was supported by the National key Research and Development Program of China ( 2019YFC1709500 ); the National Collaboration Project of Critical Illness by Integrating Chinese Medicine and Western Medicine ; the Project of Heilongjiang Province Innovation Team “TouYan;” the Yi-Xun Liu and Xiao-Ke Wu Academician Workstation; the Innovation Team of Reproductive Technique with Integrative Chinese Medicine and Western Medicine in Xuzhou City , China; Heilongjiang University of Chinese Medicine from the National Clinical Trial Base ; Heilongjiang Provincial Clinical Research Center for Ovary Diseases ; the Research Grant Council ( T13-602/21-N , C5045-20EF , and 14122021 ); and Food and Health Bureau in Hong Kong, China ( 06171026 ). Publisher Copyright: © 2023Peer reviewedPublisher PD

    A Smart Gate Driver IC for GaN Power Transistors

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    With the growing demands for high frequency, high temperature, and high power density applications in power electronics industry, silicon is reaching its theoretical limits. Wide band gap materials, such as GaN and SiC, have become the most popular successor candidates to keep "More than Moore" alive, due to their superior properties and mature technological process. However, there are many design challenges for driving GaN power transistors, including tight restriction on the gate voltage, EMI and reliability issues due to the large dv/dt and di/dt slew rates, the precision timing control, etc. In this thesis, an integrated smart gate driver IC with segmented output stage topology, programmable sense-FET, current sensing circuits and an on-chip stacked-based CPU for flexible digital control is presented. This IC is fabricated using TSMC's 0.18 um BCD GEN2 technology process for driving a d-mode GaN power HEMT in cascode configuration. The embedded CPU can configure all the digital control bits on-the-fly, with only 6 I/O pins. By using segmentation technique, this IC can suppress gate voltage spike and achieve switching node slope control. Compared with conventional fixed ROUT driving scheme, the gate voltage overshoot during transition is reduced by 89% with a load current of 5 A. In an 8 V to 15 V, 7.5 W boost converter operating at 1 MHz, an average EMI reduction of 4.43 dB is achieved between 40 MHz to 200 MHz, by utilizing dynamic driving strategy. When fSW = 2 MHz, the overall power conversion efficiency is improved by 6% at the rated output power. The programmable sense-FET and current sensing circuit can provide peak-current detection with a response time of 26 ns. This IC has many other add-on functions, including the active driving mode, which can change the best driving pattern on-the-fly. Compared to conventional gate drivers, the proposed driver IC offers a fully integrated solution, which eliminates the need for external controller, addition passive components, and analog circuit building for close loop regulation. System volume is reduced, while the design exibility is greatly improved.Ph.D

    A Segmented Output Stage H-Bridge IC with Tunable Gate Driver

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    In this thesis, an integrated H-bridge is presented for continuously optimizing the power conversion efficiency over a wide range of output current. The proposed IC incorporates both segmented output transistors and segmented gate drivers. This fully segmentation approach allows to flexibly change the on-resistance of the output stage power transistors and the output resistance of the gate drivers. Dynamic adjustment of these parameters allows to investigate the best combination of output power transistor size and gate driver size for any given load current. The IC chip is fabricated using TSMC's 0.18 um BCD Gen-2 process technology. The presented design when operating as a buck converter with a load current between 0.02 A and 4 A achieves efficiency improvements of 32% and 8% at light and heavy load current, respectively. Furthermore, the dynamically adjustable gate driver output resistance allows for suppression of the peak CEMI by 5.5 dBm.M.A.S
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