1,721,125 research outputs found
Electrochemical polymerization of polyhydrocarbons by reductive dehalogenation of chlorinated methanes
No full textElectrochemistry is a useful technique for mild synthesis of polymers, but the mechanisms of electrochemical polymerization are challenging to fully understand. Here, we focus on understanding the reaction mechanisms during the electrochemical polymerization of polyhydrocarbons. The overall synthetic pathway for hyperbranched polyhydrocarbons is investigated using electrochemical methods combined with spectroscopy, namely nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR). The oxidation and reduction occurring on the anode and cathode are investigated by cyclic voltammetry and NMR analyses to distinguish the functions of each electrode at the reaction initiation. Real-time FT-IR measurements during electrochemical polymerization are used to decipher the propagation steps. The termination by various suppliers of hydrogen atoms (such as aqueous hydrochloric acid) is examined via NMR spectroscopy using deuterium-labeled acetonitrile and chloroform. The participation of chlorinated methanes and of the solvent acetonitrile in the electrochemical polymerization is interrogated. Overall, these findings advance understanding of the key steps in the polymerization reaction. © 2023 The Author(s)11Nsciescopu
Analysis of Privacy-Preserving Element Reduction of Multiset Jae Hong Seo
No full textAmong private set operations, the privacy preserving element reduction of a multiset can be an important tool for privacy enhancing technology as itself or in the combination with other private set operations. Recently, a protocol, over-threshold-set-union-protocol, for a privacy preserving element reduction method of a multiset was proposed by Kissner and Song in Crypto 2005. In this paper, we point out that there is a mathematical flaw in their polynomial representation of element reduction of a multiset and the resulting protocol error from the flaw in the polynomial representation of a multiset. We correct their polynomial representation of a multiset and propose an over-threshold-set-operation-protocol based on the corrected representation
Protocol for the electrochemical polymerization of polyhydrocarbons from chlorinated methanes and an analysis of its polymerization reaction pathway
No full textThe mass production of polyhydrocarbons (PHCs) is achieved through electrochemical polymerization and its synthetic pathway is investigated using a combination of electrochemical techniques, NMR, and Fourier transform infrared (FTIR) spectroscopy. Here, we present a protocol for the electrochemical polymerization of PHCs from chlorinated methanes and an analysis of its polymerization reaction pathway. We describe steps for large-scale synthesis and characterization of PHCs and studying electrochemical polymerization reactions using cyclic voltammetry and chronoamperometry techniques along with NMR and FTIR spectroscopy using isotope-labeled reactants. For complete details on the use and execution of this protocol, please refer to Seo et al.,1 Lee et al.,2 and Seo et al.3 © 2023 The Authors11Nscopu
An automated security analysis framework and implementation for MTD techniques on cloud
No full textCloud service providers offer their customers with on-demand and cost-effective services, scalable computing, and network infrastructures. Enterprises migrate their services to the cloud to utilize the benefit of cloud computing such as eliminating the capital expense of their computing need. There are security vulnerabilities and threats in the cloud. Many researches have been proposed to analyze the cloud security using Graphical Security Models (GSMs) and security metrics. In addition, it has been widely researched in finding appropriate defensive strategies for the security of the cloud. Moving Target Defense (MTD) techniques can utilize the cloud elasticity features to change the attack surface and confuse attackers. Most of the previous work incorporating MTDs into the GSMs are theoretical and the performance was evaluated based on the simulation. In this paper, we realized the previous framework and designed, implemented and tested a cloud security assessment tool in a real cloud platform named UniteCloud. Our security solution can (1) monitor cloud computing in real-time, (2) automate the security modeling and analysis and visualize the GSMs using a Graphical User Interface via a web application, and (3) deploy three MTD techniques including Diversity, Redundancy, and Shuffle on the real cloud infrastructure. We analyzed the automation process using the APIs and showed the practicality and feasibility of automation of deploying all the three MTD techniques on the UniteCloud
Topochemical Intercalation of Graphitic Carbon Nitride with Alkali Metals in Ethylenediamine
No full textWe studied the intercalation chemistry of graphitic carbon nitride (gCN), combining theory and experimental methods. A series of new alkali-ethylenediamine-gCN products were prepared using a one-pot topochemical synthesis method. Spectroscopic and thermal analyses showed that single-stage intercalated gCN compounds of Li-(ethylenediamine)(0.2) (C3N4.5H1.5)(1.0) and Na(ethylenediamine)(0.3)(C3N4.5H1.5)(0.9) with ordered layer structures were formed. X-ray diffractograms indicated a large gallery expansion of 0.349 and similar to 0.342 nm for Li- and Na-intercalated gCN. In the case of K-en-gCN, a nanocomposite was formed that underwent spontaneous in situ exfoliation followed by disordered restacking to form thin flakes. Molecular dynamics studies showed that ethylenediamine molecules were distributed at the center of the interlayer spaces, predominantly adopting a trans conformation. Different types of gallery sites were present for the intercalation of guest alkali metals, leading to a high degree of topochemical intercalation with organic entities under lower temperatures than previously reported in thermal intercalation experiments. Our new synthesis route enables facile intercalation to tune interlayer spacing in gCN
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Abstract 2121: Deguelin-derivative, L80 suppresses tumor growth and metastasis via inhibition of STAT3 activation in triple-negative breast cancer
No full textAbstract
Triple-negative breast cancer TNBC is associated with aggressive metastasis and poor clinical outcomes due to a lack of effective treatment options. Therefore, new drugs that effectively target both cancer cell proliferation and metastasis are needed to improve clinical outcomes. The 90-kDa molecular chaperone heat-shock protein, HSP90 has been implicated in cancer progression and metastasis by modulating the stabilization and maturation of many oncogenic proteins. Our objective was to investigate the mechanism of action of C-terminal HSP90 inhibitor, deguelin-derivative L80 on TNBC proliferation and metastasis in vitro and in vivo. L80 induced apoptosis and suppression of cell viability in TNBC cell lines via inhibition of Akt activation with concomitant nuclear accumulation of p27. L80 treatment also caused a marked suppression of cell migration and invasion. These responses were associated with inhibition of STAT3 phosphorylation (Tyr705) as evidenced by downregulation of STAT3 downstream target genes including cyclin D1 and survivin. The syngeneic orthotopic mouse model with 4T1 cells, L80 administration resulted in significant reduction in tumor growth together with decreased number of Ki-67-positive cells and downregulation of phospho-STAT3. Double-label immunofluorescence analysis showed that individuals receiving L80 exhibited a marked reduction in co-localization and expression of HIF-1α and HSP90 compared to their control groups in vivo. Finally, we observed that L80 administration significantly suppressed lung metastasis, as determined by in vivo bioluminescent imaging system. Our findings suggest that L80 may be potentially effective for the treatment for metastatic TNBC patients.
Note: This abstract was not presented at the meeting.
Citation Format: Tae-Min Cho, Eunhye Oh, Daeil Sung, Yoon-Jae Kim, Ji Young Kim, Jeewoo Lee, Jae Hong Seo. Deguelin-derivative, L80 suppresses tumor growth and metastasis via inhibition of STAT3 activation in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2121. doi:10.1158/1538-7445.AM2017-2121</jats:p
Abstract 5463: Disulfiram suppresses metastasis via induction of anoikis and calpain activation in triple-negative breast cancer
No full textAbstract
Triple-negative breast cancers (TNBC) exhibit aggressive phenotypes and are associated with poor clinical outcomes due to a lack of effective therapeutic strategies. Disulfiram (DSF) is a clinical therapeutic drug for the treatment of alcoholism, and has also been shown to exhibit antitumor activity in TNBC cells in a copper (Cu)-dependent manner, although how this occurs has not been clearly elucidated. We sought to investigate the mechanisms responsible for DSF/Cu-dependent induction of apoptosis and suppression of lung colonization by TNBC cells. DSF/Cu treatment significantly induced apoptosis, accompanied by an increase in the sub-G1 population, as well as caspase-3 activation. DSF/Cu strongly suppressed cell migration and invasion, while inducing suppression of focal adhesion kinase (FAK) phosphorylation and focal adhesions, concomitant with an observed reorganization of cytoskeletal F-actin and collapse of the plasma membrane. These effects were associated with calpain activation, coinciding with the breakdown of vimentin, FAK and talin, presumably allowing for cell detachment. In a xenograft tumor model, DSF suppressed tumor growth and lung colonization, which was also associated with calpain activation. Taken together, these findings warrant further investigation of disulfiram as a potential treatment for metastatic TNBC.
Citation Format: Eunhye Oh, Daeil Sung, Youngkwan Cho, Ji Young Kim, Nahyun Lee, Yoon-Jae Kim, Tae-Min Cho, Jae Hong Seo. Disulfiram suppresses metastasis via induction of anoikis and calpain activation in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5463. doi:10.1158/1538-7445.AM2017-5463</jats:p
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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