672 research outputs found
Interleukin-1 mediated cell-type specific signaling in hippocampal neurons and astrocytes
No full textInterleukin-1β (IL-1β) is a pro-inflammatory cytokine that is implicated in immune and inflammatory responses. In the central nervous system (CNS), IL-1β is synthesized and released during injury, infection, and many neurodegenerative diseases, but also under physiological conditions. Several IL-1-mediated signaling pathways and effects have been identified in hippocampal neurons and astrocytes, but their mechanisms have not been fully defined. IL-1 signaling requires the type one IL-1 receptor (IL-1RI) as well as IL-1 receptor accessory protein (IL-1RAcP) as a receptor partner. A novel isoform of the IL-1 receptor accessory protein, AcPb, has also been found in the CNS, but its role remains unclear. This thesis examined AcPb function in regulating IL-1β signaling. The results showed that IL-1β activated p38 MAPK but not NFκB in neurons. In astrocytes, IL-1β induced both p38 and NFκB pathways in regulating inflammatory responses. AcPb was not involved in mediating either p38 or NFκB in either cell type. In contrast, a physiological level of IL-1β treatment (0.01ng/ml) activated p-Src in neurons via AcPb in vitro. In addition, overexpression of AcPb in astrocytes was sufficient to induce p-Src mediated by IL-1β. Taken together, these results suggest that the restricted expression of AcPb in CNS neurons may mediate neuronal specific IL-1 pathways and outcomes, and that physiological and pathophysiological levels of IL-1β mediate particular neuronal functions via separate pathways.Ph. D.Includes abstractIncludes bibliographical referencesby Yangyang Huan
Molecular simulations of rheological, mechanical and transport properties of solid-fluid systems:
No full textIn this dissertation, two distinct but relevant systems are chosen as representatives of interesting solid-fluid systems. Molecular dynamics (MD) and Monte Carlo techniques are applied to investigate the rheological, mechanical and transport properties of these systems.
Firstly, polyethylene melt embedded with silica nanoparticles is examined to be of our interest. Since it is computationally impractical to model a complex system with a molecular description, a multiscale modeling approach, which combines both atomistic and mesoscale simulations, is employed to efficiently represent and study the polymer nanoparticle systems. Based on a coarse-grained force field for polyethylene, a novel method is developed for determining the solid-fluid interaction at the spherical interface. Our coarse grained model is designed to mimic 4 nm silica nanoparticles in polyethylene melt at 423K. A series of MD simulations are performed to investigate the factors that control the homogeneity of nanofillers inside polymer matrix, also in the presence of nonionic surfactants (short chain alcohols). The effects of nanoparticle filling fraction, polymer chain length, and relative sizes between nanoparticles and polymer chains on the particle dispersion are explored. In addition, a fundamental relationship is pursued between the microstructure and macroscopic properties (transport and rheological) of polymer nanoparticle composites.
In this work another method for determining the solid-fluid interaction parameter is presented: the experimental adsorption isotherms are used to validate the potential parameters. The rapid expansion of silica nanoparticle agglomerates in supercritical carbon dioxide (RESS process) is chosen to be the system of interest. The simulations show that the effective attraction between two identical nanoparticles is most prominent for densely hydroxylated particle surfaces that interact strongly with CO2 via hydrogen bonds, while it is significantly weaker for dehydroxylated particles. We also explore the shearing forces necessary to break an agglomerate in supercritical fluid. The agglomerate experiences deformation followed by elongation, and finally break-up. The calculated diffusion coefficient of CO2 is expected to be smaller than the experimental value, because the nanoparticle agglomerate hinders fluid movement. In the direction of shearing forces, the diffusion of CO2 shows a steep increase after the breakup, confirming the rupture of the agglomerate.Ph.D.Includes bibliographical references (p. 136-142)by Yangyang She
30m winter wheat distribution map of China for three years (2016-2018)
No full text*** 1. Introductory information ***Title: Distribution map of winter wheat in China with 30-m spatial resolution for three years (2016-2018)Format: TIFNaming convention: "winter wheat map-2016.tif" means winter wheat map of 2016.Authors: Jie Dong, Yangyang Fu, Jingjing Wang, Haifeng Tian, Shan Fu, Zheng Niu, Wei Han, Yi Zheng, Jianxi Huang, Wenping YuanState Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal UniversityCorresponding author: Wenping YuanContact Information: [email protected] (J.D.); [email protected] (W.Y.)*** 2. Methodological information ***Method description: A phenology-based method are used to produce the winter wheat distribution map in China by comparing the similarity of the seasonal changes of satellite-based vegetation index over all croplands with a standard seasonal change derived from known winter wheat fields.Software: Arcgis or ENVI are needed to read the dataset.*** 3. Data specific information ***The dataset contains winter wheat maps with 30m spatial resolution for three years (2016-2018) over eleven provinces, which produce more than 98% of the winter wheat in China.In the datasets, the values equal to one means winter wheat, and the values equal to zero means non-winter wheat
Towards robust malware detection
No full textThesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 45-48).A central challenge of malware detection using machine learning methods is the presence of adversarial variants, small changes to detectable malware that allow it to evade a model (i.e. be classified as benign). We take inspiration from adversarial variant generation methods in the continuous-valued image domain to introduce methods for malware in the binary domain. We incorporate these methods in the training of hardened models towards the goal of robustness against adversarial variants. Additionally, we provide visualization tools for analysis of hardened models. Our tools illustrate the difference in loss behavior between models trained with different methods, the effect of adversarial learning on the loss landscape of a model, and the effect of adversarial learning on the decision map of a model. The adversarial learning framework and the visualization tools in combination allow for the creation and understanding of robust models.by Alex Yangyang Huang.M. Eng
Lectures on Brill-Noether theory
No full textThese notes are the summary of lectures given by the author, in the framework of Joint Lectures of F. Flamini and E. Sernesi, at the Workshop
”Curves and Jacobians”, organized by the Korean Institute of Advanced Study (Seoul) and held on October 18-21, 2010, at Sol Beach Resort, Yangyang (Korea
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Market Analysis of Cross-Border E-commerce: A Business Model Comparison
No full textThis paper aims to explore the factors that shape the business models of cross-border e-commerce (CBEC) platforms and how these models can be optimized to enhance market performance and operational efficiency. This study would employ a comparative case study approach by using the Business Model Canvas (BMC), which consists of nine key elements (Customer Segments, Value Propositions, Channels, Customer Relationships, Revenue Streams, Key Resources, Key Activities, Key Partnerships, and Cost Structure), to analyze two major CBEC platforms: Alibaba Global and Shopify. A qualitative method would be adopted, combining a structured framework to evaluate platform performance and strategies. The findings of this research could theoretically contribute to the CBEC and business model by applying the BMC to analyze platform strategies, which could help to fill the gap of a lack of comparison of two different e-commerce platforms in the context of CBEC. Helping to contribute to giving a comprehensive understanding of CBEC platforms and giving some insights about how BMC shapes success. Additionally, this study could provide actionable insights into best practices for optimizing CBEC platforms in terms of practical implications. It could also offer some insights for startups about how to apply BMC
A novel chemoradiation targeting stem and nonstem pancreatic cancer cells by repurposing disulfiram
No full textPancreatic ductal adenocarcinoma (PDAC) has a 5-year relative survival rate of 8% and is projected to be the second leading cause of cancer death by 2030, underscoring the urgency to develop new strategies to improve current therapeutic modalities for PDAC. Targeting pancreatic cancer stem cells (PCSCs), which are resistant to radiation and chemotherapy, is a promising strategy. A novel approach which can be readily clinically translated is to repurpose disulfiram (DSF), a drug for treating alcoholism, to target PCSCs. Chemoradiation or the combination of chemotherapy agents FOLFIRINOX, currently standard care for PDAC, can increase stemness in some established or primary PDAC cell lines. However, DSF in the presence of exogenously or endogenously supplied copper (Cu), when combined with chemotherapy or chemoradiation, targets both PCSCs and nonstem PDAC cells. Previously, we demonstrated that DSF/Cu effectively targets breast cancer stem cells in the context of fractionated radiation (FIR) by inhibiting the NF-ÎoBâstemness gene pathway. Therefore, the hypothesis that PCSCs can be effectively targeted by incorporating DSF/Cu into the standard chemoradiation regimen consisting of 5-FU and FIR was investigated and found to be effective in vitro in targeting PCSCs, identified as either ALDHbrightor CD24+/CD44+/ESA+ or sphere-forming cells, as well as nonstem PDAC cells. In vivo, the combination of IR+5-FU+DSF/Cu was more effective (72.46%) than either IR+5-FU (30.32%) or IR+FOLFIRINOX therapy (43.04%) in inhibiting growth of the mouse Panc02 tumor. These encouraging results provide a solid foundation for clinical trials to improve the outcomes of the current standard chemoradiation therapy regimen for PDAC
Correction: Influenza vaccination in patients with acute heart failure (PANDA II): study protocol for a hospital-based, parallel-group, cluster randomized controlled trial in China
No full textFollowing the publication of the original article [1], we were notified of a few errors in the affiliation numbers assigned to the 4th and last author, as well as in the first and last corresponding email addresses (changes marked in bold). Originally assigned affiliations: Yiqun Zhang1, Rong Liu2, Yangyang Zhao1, Zhiyan Wang3,4, Chi Wang1, Qiang Li2, Dorothy Han1, Craig S. Anderson1,2,3*, Xin Du1,4* and Jianzeng Dong3,5* Correct affiliation assignment: Yiqun Zhang1, Rong Liu2, Yangyang Zhao1, Zhiyan Wang4, Chi Wang1, Qiang Li2, Dorothy Han1, Craig S. Anderson1,2,3*, Xin Du1,4* and Jianzeng Dong4,5* Originally published correspondence emails: [email protected], [email protected], [email protected] Corrected correspondence emails: [email protected], [email protected], [email protected] Originally assigned affiliations: Yiqun Zhang1, Rong Liu2, Yangyang Zhao1, Zhiyan Wang3,4, Chi Wang1, Qiang Li2, Dorothy Han1, Craig S. Anderson1,2,3*, Xin Du1,4* and Jianzeng Dong3,5* Correct affiliation assignment: Yiqun Zhang1, Rong Liu2, Yangyang Zhao1, Zhiyan Wang4, Chi Wang1, Qiang Li2, Dorothy Han1, Craig S. Anderson1,2,3*, Xin Du1,4* and Jianzeng Dong4,5* Originally published correspondence emails: [email protected], [email protected], [email protected] Corrected correspondence emails: [email protected], [email protected], [email protected] In addition, on page 2, in the Trials design {8} section, the sentence “Hospitals are centrally randomly allocated to be an intervention arm to provide a free POV influenza vaccination in wards devoted to the care of patients with HF.” needs to read “Hospitals are centrally randomly allocated to be an intervention arm to provide a free influenza vaccination in wards devoted to the care of patients with HF.” AND sentence “The control hospitals are to provide usual standard of care without routine POV but can make recommendations to patients to receive their influenza vaccination at community health care center.” should read “The control hospitals are to provide usual standard of care without routine Point of Vaccination (POV) but can make recommendations to patients to receive their influenza vaccination at community health care center.” (the word POV has been removed from both sentences). On page 8, under the Plans for communicating important protocol amendments to relevant parties (e.g., trial participants, ethical committees) {25} section, ClinicalTrials.gov. was changed into https://www.chictr.org.cn. The original article has been corrected
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