1,847 research outputs found
The linear stability of weakly charged and slowly rotating Kerr-Newman family of charged black holes
In this paper, we prove the linear stability of weakly charged and slowly
rotating Kerr-Newman black holes under coupled gravitational and
electromagnetic perturbations. We show that the solutions to the linearized
Einstein-Maxwell equations decay at an inverse polynomial rate to a linearized
Kerr-Newman solution plus a pure gauge term. This work builds on the framework
developed by H\"{a}fner-Hintz-Vasy for the study of the Einstein vacuum
equations. We work in the generalized wave map and Lorenz gauge. The proof
involves the analysis of the resolvent of the Fourier transformed linearized
Einstein-Maxwell operator on asymptotically flat spaces, which relies on recent
advances in microlocal analysis and non-elliptic Fredholm theory developed by
Vasy. The most delicate part of the proof is the description of the resolvent
at low frequencies.Comment: 180 pages, 11 figures; Typo corrected, referenced added, section 2,
3, 4 revised, results unchange
Application of surface enhanced Raman spectroscopy to food safety issues
Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 23, 2010).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Mengshi Lin.Vita.Ph. D. University of Missouri--Columbia 2009.In recent years, food safety issues caused by contamination of chemical substances or microbial species have raised a great deal of concern in the United States. Conventional chromatography-based methods for detection of chemical contaminants and microbial plating methods for detection of food-borne pathogens are time-consuming and labor-intensive. In this project, we explored the feasibility of using surface enhanced Raman spectroscopy (SERS) coupled with a variety of substrates (e.g. commercial gold substrates, fractal-like gold nanoaggregates, silver dendrites, and gold-coated zinc oxide nanonecklaces) for detection of various chemical and microbiological food contaminants, including melamine and its analogues, restricted antibiotics and prohibited dyes, and Bacillus spores. Our results demonstrate that SERS is capable of detecting, characterizing, and differentiating chemical and microbiological contaminants in foods quickly and accurately. The limit of detection of SERS could reach a single spore or parts per billion level for chemical samples. These results indicate a great potential of using SERS techniques for rapid detection, classification, and quantification of chemical and biochemical contaminants in food products.Includes bibliographical reference
Spatholobus suberectus extract suppresses proliferation and EMT, and promotes apoptosis in palmitic acid induced vascular endothelial cells by inhibiting LncRNA MALAT1 via VEGF signaling pathway
Purpose: In type 2 diabetes, palmitic acid could damage vessels and induce insulin resistance. This present in vitro study evaluates the possible role of Spatholobus suberectus (FSS) extract in diabetes.Methods: Human HUVECc cells were treated with palmitic acid, palmitic acid and Spatholobus suberectus extract. MALAT1 overexpression plasmid (pcDNA-MALAT1) and blank vector were transfected into the cells using lipofectamine 2000. RT-qPCR assay was used to evaluated the expression changes of lncRNA, VEGFR2 and VEGFA in the cells as well as Epithelial-Mesenchymal Transition (EMT) biomarkers and apoptosis. CCK-8 was used to detect cell viabilities of HUVECs. Expressions of proteins in VEGF signaling pathway were analyzed using Western Blot.Results: LncRNA MALAT1 had high expression in diabetes-like cells and suppressed proliferation and EMT but promoted apoptosis. The SS extract promoted proliferation and EMT and repressed apoptosis in diabetes-like HUVECs cells. The promotion of apoptosis by LncRNA MALAT1, inhibition of apoptosis and regulated functions of diabetes-like HUVECs cells by SS extract occurred via the VEGF signaling pathwayConclusion: SS extract might contribute to survival of cells by inhibiting MALAT1 via VEGF signaling pathway in vitro, suggesting FSF might be a potential therapeutic agent in the treatment of diabetes.
Keywords: flavone of Spatholobus suberectus, diabetes, vascular endothelial cell, LncRNA MALAT
La interacción entre identidad y emoción de los jóvenes profesores de IDAI (idiomas distintos al inglés) en los inicios de su carrera profesional: La teoría sociocultural
There is conflicting evidence regarding the relationship between teachers’ identities and emotions. The inconsistency may be explained by a one-way causal relationship or two-way support. However, from a sociocultural perspective, the two might dialectically influence each other. Furthermore, most studies on teacher identities have focused solely on teaching and research identities without considering their social service roles as well. Further, little is known about LOTE (Languages Other than English) teachers in higher education, and even less is known about younger novice teachers. To fill these gaps, this study included a survey of 843 young LOTE teachers and in-depth interviews with three respondents at universities to gain a deeper understanding of their identities and emotions. As a result, the interaction between the two variables in the teaching dimension was observed to have a more robust relationship. Teachers’ identities and emotions were inextricably linked in either a positive or negative manner. Specifically, a higher sense of identity and positive emotion correlated closely, whereas a lower sense of identity and negative emotion walked together. As a result of the weak sense of research identity, this relationship was evident in teaching and social service, de-emphasizing research. The present study provides additional evidence with respect to the dialectical relationship between teacher identity and teacher emotion.
FUNDING INFORMATION. The project has been primarily supported by Research Fund for Yunshan Outstanding Scholar, Guangdong University of Foreign Studies (No. 2023RC031), the MOE Project at Center for Linguistics and Applied Linguistics, Guangdong University of Foreign Studies, Shanghai International Studies University Peak Discipline (Linguistics) Construction Project (N0. 41004525/001), and Shanghai International Studies University Mentor Academic Leadership Program (N0. 2022113041).
The paper has also been supported by: An Empirical Study on the Impact of Public Sponsored Study Abroad on the Professional Development of University Teachers-Taking Guangdong as an Example (N0: GD22CJY10).La literatura existente es contradictoria sobre la relación entre las identidades y las emociones de los profesores. La inconsistencia puede explicarse mediante una relación causal unidireccional o un apoyo bidireccional. Sin embargo, desde una perspectiva sociocultural, ambas podrán influenciarse dialéctica. Además, la mayoría de los estudios sobre las identidades de los profesores ha habido centrado en las enseñanzas e investigadoras sin el servicio social. Por lo demás, se ha investigado poco sobre los profesores IDAI (idiomas distintos al inglés) y aún menos sobre los profesores jóvenes. Para colmar estas lagunas, el estudio incluyó encuestas a 843 jóvenes profesores y entrevistas con tres de los encuestados. Mostró que las dos interacciones destacaron en la enseñanza y el servicio social, mientras que se restaron importancia a la investigación debido al débil sentido de la identidad investigadora. Y las identidades y emociones se desarrollaron en un patrón inextricable en una tendencia positiva o negativa. Un mayor sentido de la identidad y la emoción positiva estuvieron estrechamente relacionados, mientras que la identidad de bajo sentido o de reconstrucción y la emoción negativa caminaron juntos. El presente estudio demuestra una evidencia adicional con respecto a la relación dialéctica entre las identidades y las emociones de los profesore
Bridge Design between AXI Lite and AHB Bus Protocol
Architecture of bridge model between AXI Lite and AHB for this paper were simulated using Synopsys VCS and DC in Verilog HDL. Bridge structure mainly comprises of arbitration techniques, control signals, multiplexing techniques for writing data signals and Decoder for reading data section. In this work, bridge model between AHB and AXI lite was simulated and characterized. The proposed model of bridge design provides efficient communication between on chip bus protocols like AXI and AHB on chip in the era of deep sub-micron technology where channel side is reduced as much as 5 nm
Numerical Simulation of the Ion Transport Behavior in Concrete under Coupled Axial Loading and Sulfate Attack
During a sulfate attack on concrete, ions, which are transported to the interior of concrete through pores, react with the concrete components. The transport characteristics are affected by various factors. A chemical-mechanical coupling method for accurately evaluating the transport behavior of sulfate ions in concrete under stress conditions was proposed in this study to investigate the transport characteristics of these ions. The diffusion-reaction equations of sulfate ions were obtained based on the diffusion-reaction approach in combination with the mechanism of volume expansion under a sulfate attack and the influence of load on the concrete voidage. The constitutive response and crack density of the matrix were calculated according to the volumetric strain caused by external load and ettringite growth. Then, the diffusion coefficient of the equation was dynamically corrected. T\u27his phenomenon was a strongly coupled moving boundary problem, and the equations were solved using numerical method. A case study was conducted to analyze the distribution law of ionic concentration and volumetric strain obtained using the proposed method. Results demonstrate that the crack damage due to volumetric strain plays a major role in the diffusion of sulfate ions. The load has minimal effect on the transport behavior under a low stress level, and the water-cement ratio is negatively correlated with ion transport capacity. The proposed method serves as a reference for evaluating the durability of an underground structure in a sulfate formation
Tunable atomic arrangements of platinum catalysts for the nucleation of single-wall carbon nanotubes
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