154 research outputs found
Dynamics of pedogenic carbonate in the cropland of the North China Plain : Influences of intensive cropping and salinization
This research was supported by the National Natural Science Foundation of China (41877028). The input of Pete Smith contributes to the UK-China Virtual Joint Centre on Nitrogen, N-Circle (BB/N013484/1), funded under the Newton Fund, and the NERC-funded project Soils-R-GRREAT (NE/P019455/1). The authors have no conflict of interest to declare.Peer reviewedPostprin
Deep Dyna-Q: Integrating Planning for Task-Completion Dialogue Policy Learning
Training a task-completion dialogue agent via reinforcement learning (RL) is
costly because it requires many interactions with real users. One common
alternative is to use a user simulator. However, a user simulator usually lacks
the language complexity of human interlocutors and the biases in its design may
tend to degrade the agent. To address these issues, we present Deep Dyna-Q,
which to our knowledge is the first deep RL framework that integrates planning
for task-completion dialogue policy learning. We incorporate into the dialogue
agent a model of the environment, referred to as the world model, to mimic real
user response and generate simulated experience. During dialogue policy
learning, the world model is constantly updated with real user experience to
approach real user behavior, and in turn, the dialogue agent is optimized using
both real experience and simulated experience. The effectiveness of our
approach is demonstrated on a movie-ticket booking task in both simulated and
human-in-the-loop settings.Comment: 11 pages, 8 figures, Accepted in ACL 201
CircUBAP2 Promotes MMP9-Mediated Oncogenic Effect via Sponging miR-194-3p in Hepatocellular Carcinoma
BackgroundThe physiological regulatory functions of circRNAs have become a topic of intensive research in recent years. Increasing evidence supports a significant role of circRNAs during cancer initiation and progression, including hepatocellular carcinoma (HCC).Materials and MethodsA bioinformatics analysis from three independent Gene Expression Omnibus (GEO) databases was performed to profile and screen the dysregulated circRNAs in HCC. RT-qPCR was used to examine the expression level of circUBAP2 in HCC and adjacent non-tumor tissues. Then, proliferation assays (CCK8 and colony formation) and migration assays (transwell and wound healing) were performed to examine effect of circUBAP2 in vitro. Immunoprecipitation, RNA pulldown, FISH, and dual-luciferase reporter assay was conducted to explore the circUBAP2-related mechanism for regulating HCC progression. Moreover, a mouse xenograft model and a mouse lung metastasis model confirmed the effect of circUBAP2 in vivo.ResultsIn this study, we found a novel circRNA: circUBAP2, which was identified by bioinformatics analysis. Among 91 HCC patients, circUBAP2 was significantly upregulated in HCC tissues, and negatively correlated with aggressive clinical characteristics and prognosis. Functional assays demonstrated that circUBAP2 promoted cell proliferation, colony formation, migration, and invasion in vitro. Moreover, circUBAP2 enhanced tumor growth and pulmonary metastasis in vivo. Mechanistically, circUBAP2 acts as a competing endogenous RNA (ceRNA) for miR-194-3p, a tumor suppressor in HCC. We confirmed that MMP9 was direct target for miR-194-3p, which was regulated by circUBAP2.ConclusionCircUBAP2 plays a significant role in promoting HCC via the miR-194-3p/MMP9 pathway and could serve as a promising prognostic biomarker and novel therapeutic target for HCC patients
Sphingosine kinase 1āmediated inhibition of Fas death signaling in rheumatoid arthritis B lymphoblastoid cells
Objective It is becoming increasingly apparent that B cells play an important role in the pathogenesis of rheumatoid arthritis (RA). Due to the scarcity of B cells in RA, it has been technically difficult to functionally characterize B cell apoptosis in this disease. As a necessary first step to identify candidate aberrations, we investigated Fas-mediated signaling events in immortalized peripheral blood B lymphoblastoid cell lines (LCLs) from patients with RA and controls. Methods Cell death was determined by the MTS assay, and apoptosis was detected by the TUNEL assay and DNA laddering. Proteolytic activation of caspase 3 was determined by immunoblotting, and its enzymatic activity was determined by a fluorometric technique. Messenger RNA (mRNA) expression was quantified by real-time polymerase chain reaction (PCR) analysis. The functional role of sphingosine kinase (SPHK) was determined by measuring its enzymatic activity, by quantifying the levels of its product, sphingosine 1-phosphate (S1P), and by investigating the ability of the SPHK inhibitor N , N -dimethylsphingosine and isozyme-specific small interfering RNA (siRNA) oligonucleotides to reverse signaling aberrations. Results LCLs from patients with RA displayed disease-specific Fas-mediated signal transduction impairment with consequent resistance to cell death. RA LCLs displayed high constitutive SPHK activity and increased levels of S1P. Real-time PCR analysis showed higher SPHK-1 mRNA expression levels in RA patients compared with paired controls. Increased SPHK-1 (but not SPHK-2) mRNA levels were observed in synovial tissue from RA patients. Competitive inhibitors of SPHK reversed the resistance of RA LCLs to Fas-induced apoptosis. Additionally, resistance to Fas-mediated signaling was reversed by siRNA oligonucleotides specific for SPHK-1 but not by oligonucleotides specific for SPHK-2. Conclusion These findings demonstrate disease-specific resistance to Fas-mediated death signaling in patients with RA and implicate increased SPHK-1 activity as the cause of this aberration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49513/1/21635_ftp.pd
Regulation of Ferredoxin-NADP+ Oxidoreductase to Cyclic Electron Transport in High Salinity Stressed Pyropia yezoensis
Pyropia yezoensis can survive the severe water loss that occurs during low tide, making it an ideal species to investigate the acclimation mechanism of intertidal seaweed to special extreme environments. In this study, we determined the effects of high salinity on photosynthesis using increasing salinity around algal tissues. Both electron transport rates, ETR (I) and ETR (II), showed continuous decreases as the salinity increased. However, the difference between these factors remained relatively stable, similar to the control. Inhibitor experiments illustrated that there were at least three different cyclic electron transport pathways. Under conditions of severe salinity, NAD(P)H could be exploited as an endogenous electron donor to reduce the plastoquinone pool in Py. yezoensis. Based on these findings, we next examined how these different cyclic electron transport (CETs) pathways were coordinated by cloning the gene (HM370553) for ferredoxin-NADP+ oxidoreductase (FNR). A phylogenetic tree was constructed, and the evolutionary relationships among different FNRs were evaluated. The results indicated that the Py. yezoensis FNR showed a closer relationship with cyanobacterial FNR. The results of both real-time polymerase chain reaction and western blotting showed that the enzyme was upregulated under 90ā120ā° salinity. Due to the structure-function correlations in organism, Py. yezoensis FNR was proposed to be involved in NAD(P)H-dependent Fd+ reduction under severe salinity conditions. Thus, through the connection between different donors bridged by FNR, electrons were channeled toward distinct routes according to the different metabolic demands. This was expected to make the electron transfer in the chloroplasts become more flexible and to contribute greatly to acclimation of Py. yezoensis to the extreme variable environments in the intertidal zone
Regulatory Mechanisms of the Wnt/Ī²-Catenin Pathway in Diabetic Cutaneous Ulcers
Skin ulcers are a serious complication of diabetes. Diabetic patients suffer from vascular lesions and complications such as peripheral neuritis, peripheral vascular lesions, and collagen abnormalities, which result in skin wounds that are refractory and often develop into chronic ulcers. The healing of skin ulcers requires an inflammatory reaction, wound proliferation, remodeling regulation, and control of stem cells. Studies investigating diabetic cutaneous ulcers have focused on cellular and molecular levels. Diabetes can cause nerve and blood vessel damage, and persistent high blood sugar levels can cause systemic multisite nerve damage based on peripheral neuropathy. The long-term hyperglycemia state enables the polyol glucose metabolism pathway to be activated, increasing the accumulation of toxic substances in the vascular injured nerve tissue cells. Sustained hyperglycemia leads to dysfunction of epithelial cells, leading to a decrease in pro-angiogenic signaling and nitric oxide production. In addition, due to impaired leukocyte function in hyperglycemia, immune function is impaired and the immune response at relevant sites is insufficient, making diabetic foot more difficult to heal. The Wnt/Ī²-catenin pathway is a highly conserved signal transduction pathway involved in a variety of biological processes, such as cell proliferation, apoptosis, and differentiation. It is considered an important pathway involved in the healing of skin wounds. This article summarizes the mechanism of action of the Wnt/Ī²-catenin pathway involved in the inflammatory responses to diabetic ulcers, wound proliferation, wound remodeling, and stem cells. The interactions between the Wnt signal pathway and other metabolic pathways are also discussed
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