41 research outputs found

    Novelties of solid-liquid phase transfer catalyzed synthesis of benzyl diethyl phosphate from the sodium salt of diethyl phosphate

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    Solid-liquid phase transfer catalysis coupled with mixed solvents, which could be recycled, as a green chemistry procedure, was applied to the synthesis of phosphate from the sodium salt of diethyl phosphate. The benzyl diethyl phosphate was synthesized in good yield via one-pot method from the reaction of the industrial by-product sodium salt of diethyl phosphate with benzyl chloride in solid-liquid phase transfer catalysis and toluene-water mixed solvents. The effects of catalyst structure, the amounts of catalyst, the raw material molar ratio, water loading, and reaction temperature on the conversion of the reaction were investigated. The structure of the benzyl diethyl phosphate generated was confirmed by Elemental Analysis, IR, 1H NMR and GC/MS

    Optimal operation of interconnected energy hubs by using decomposed hybrid particle swarm and interior-point approach

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    The Energy Hub has become an important concept for formally optimizing multi-carrier energy infrastructure to increase system flexibility and efficiency. The existence of energy storage within energy hubs enables the dynamic coordination of energy supply and demand against varying energy tariffs and local renewable generation to save energy cost. The battery lifetime cost may be included in the optimization objective function to better utilize battery for long term use. However, the operational optimization of an interconnected energy hub system with battery lifetime considered presents a highly constrained, multi-period, non-convex problem. This paper proposes Particle Swarm Optimization (PSO) hybridised with a numerical method, referred to collectively as the decomposition technique. It decouples the complicated optimization problem into sub-problems, namely the scheduling of storage and other elements in the energy hub system, and separately solves these by PSO and the numerical method ā€˜interior-pointā€™. This approach thus overcomes the disadvantages of numerical methods and artificial intelligence algorithms that suffer from convergence only to a local minimum or prohibitive computation times, respectively. The new approach is applied to an example two-hub system and a three-hub system over a time horizon of 24 h. It is also applied to a large eleven-hub system to test the performance of the approach and discuss the potential applications. The results demonstrate that the method is capable of achieving very near the global minimum, verified by an analytical approach, and is fast enough to allow an online, receding time horizon implementation.</p

    Frodo Links Dishevelled to the p120-Catenin/Kaiso Pathway: Distinct Catenin Subfamilies Promote Wnt Signals

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    Summaryp120-catenin is an Arm repeat protein that interacts with varied components such as cadherin, small GĀ proteins, kinases, and the Kaiso transcriptional repressor. Despite recent advances in understanding the roles that p120-catenin and Kaiso play in downstream modulation of Wnt/Ī²-catenin signaling, the identity of the upstream regulators of the p120-catenin/Kaiso pathway have remained unclear. Here, we find that p120-catenin binds Frodo, which itself interacts with the Wnt pathway protein Dishevelled (Dsh). In Xenopus laevis, we demonstrate that Wnt signals result in Frodo-mediated stabilization of p120-catenin, which, in turn, promotes Kaiso sequestration or removal from the nucleus. Our results point to Dsh and Frodo as upstream regulators of the p120-catenin/Kaiso signaling pathway. Importantly, this suggests that Wnt signals acting through Dsh regulate the stability of p120-catenin in addition to that of Ī²-catenin, and that each catenin promotes its respective signal in parallel to regulate distinct, as well as shared, direct downstream gene targets

    Market Segmentation Based on Attributes for the Purchase of Fresh Ginseng

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    This study aims to subdivide consumers by attributes determined mainly by consumers of fresh ginseng. It is to compare and analyze the characteristics by cluster, and to deduce the implications on distribution and marketing. For this study, a survey was conducted targeting 250 consumers of fresh ginseng. The factors were deduced through performing the exploratory factor analysis on the results of the survey, and the consumers of fresh ginseng were classified through cluster analysis. As a result of the study, the attributes considered for the purchase of fresh ginseng were condensed to the three factors: physical characteristic factor, safety factor, and cultivation indication information factor. With these as the standard, the consumers of fresh ginseng were subdivided into the three clusters: safety-oriented consumption type, label-centered consumption type, and high involvement consumption type. It was found that there were differences in demographic characteristics and attributes considered for purchase of fresh ginseng by cluster analysis. This study suggests the implications for revitalization of the fresh ginseng industry by subdividing consumers of fresh ginseng and suggesting the characteristics by cluster.This research was financially supported by the Rural Development Administration (RDA) of Korea (Grant No.PJ008729).OAIID:oai:osos.snu.ac.kr:snu2012-01/102/0000011251/8SEQ:8PERF_CD:SNU2012-01EVAL_ITEM_CD:102USER_ID:0000011251ADJUST_YN:NEMP_ID:A078501DEPT_CD:520CITE_RATE:0FILENAME:ģ²Øė¶€ėœ ė‚“ģ—­ģ“ ģ—†ģŠµė‹ˆė‹¤.DEPT_NM:ė†ź²½ģ œģ‚¬ķšŒķ•™ė¶€EMAIL:[email protected]_YN:NCONFIRM:

    Sirt1 coordinates with ERĪ± to regulate autophagy and adiposity

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    Sex difference in adiposity has long been recognized but the mechanism remains incompletely understood. Previous studies suggested that adiposity was regulated by autophagy in response to energy status change. Here, we show that the energy sensor Sirt1 mediates sex difference in adiposity by regulating autophagy and adipogenesis in partnership with estrogen receptor Ī± (ERĪ±). Autophagy and adipogenesis were suppressed by Sirt1 activation or overexpression, which was associated with reduced sex difference in adiposity. Mechanistically, Sirt1 deacetylated and activated AKT and STAT3, resulting in suppression of autophagy and adipogenesis via mTOR-ULK1 and p55 cascades. ERĪ± induced Sirt1 expression and inhibited autophagy in adipocytes, while silencing Sirt1 reversed the effects of ERĪ± on autophagy and promoted adipogenesis. Moreover, Sirt1 deacetylated ERĪ±, which constituted a positive feedback loop in the regulation of autophagy and adiposity. Our results revealed a new mechanism of Sirt1 regulating autophagy in adipocytes and shed light on sex difference in adiposity

    Targeted Expression of Cre Recombinase Provokes Placental-Specific DNA Recombination in Transgenic Mice

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    Background: Inadequate placental development is associated with a high incidence of early embryonic lethality and serious pregnancy disorders in both humans and mice. However, the lack of well-defined trophoblast-specific gene regulatory elements has hampered investigations regarding the role of specific genes in placental development and fetal growth. Principal Findings: By random assembly of placental enhancers from two previously characterized genes, trophoblast specific protein a (Tpbpa) and adenosine deaminase (Ada), we identified a chimeric Tpbpa/Ada enhancer that when combined with the basal Ada promoter provided the highest luciferase activity in cultured human trophoblast cells, in comparison with non-trophoblast cell lines. We used this chimeric enhancer arrangement to drive the expression of a Cre recombinase transgene in the placentas of transgenic mice. Cre transgene expression occurred throughout the placenta but not in maternal organs examined or in the fetus. Significance: In conclusion, we have provided both in vitro and in vivo evidence for a novel genetic system to achieve placental transgene expression by the use of a chimeric Tpbpa/Ada enhancer driven transgene. The availability of thi

    DEVELOPMENTAL AND CELLULAR FUNCTIONS OF DELTA-CATENIN

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    Catenins have diverse and powerful roles in embryogenesis, homeostasis or disease progression, as best exemplified by the well-known beta-catenin. The less studied delta-catenin likewise contains a central Armadillo-domain. In common with other p120 sub-class members, it acts in a variety of intracellular compartments and modulates cadherin stability, small GTPase activities and gene transcription. In mammals, delta-catenin exhibits neural specific expression, with its knock-out in mice correspondingly producing cognitive defects and synaptic dysfunctions. My work instead employed the amphibian, Xenopus laevis, to explore delta-cateninā€™s physiological functions in a distinct vertebrate system. Initial isolation and characterization indicated delta-cateninā€™s expression in Xenopus. Unlike the pattern observed for mammals, delta-catenin was detected in most adult Xenopus tissues, although enriched in embryonic structures of neural fate as visualized using RNA in-situ hybridization. To determine delta-cateninā€™s requirement in amphibian development, I employed anti-sense morpholinos to knock-down gene products, finding that delta-catenin depletion results in developmental defects in gastrulation, neural crest migration and kidney tubulogenesis, phenotypes that were specific based upon rescue experiments. In biochemical and cellular assays, delta-catenin knock-down reduced cadherin levels and cell adhesion, and impaired activation of RhoA and Rac1, small GTPases that regulate actin dynamics and morphogenetic movements. Indeed, exogenous C-cadherin, or dominant-negative RhoA or dominant-active Rac1, significantly rescued delta-catenin depletion. Thus, my results indicate delta-cateninā€™s essential roles in Xenopus development, with contributing functional links to cadherins and Rho family small G proteins. In examining delta-cateninā€™s nuclear roles, I identified delta-catenin as an interacting partner and substrate of the caspase-3 protease, which plays critical roles in apoptotic as well as non-apoptotic processes. Delta-cateninā€™s interaction with and sensitivity to caspase-3 was confirmed using assays involving its cleavage in vitro, as well as within Xenopus apoptotic extracts or mammalian cell lines. The cleavage site, a highly conserved caspase consensus motif (DELD) within Armadillo-repeat 6 of delta-catenin, was identified through peptide sequencing. Cleavage thus generates an amino- (1-816) and carboxyl-terminal (817-1314) fragment each containing about half of the central Armadillo-domain. I found that cleavage of delta-catenin both abolishes its association with cadherins, and impairs its ability to modulate small GTPases. Interestingly, the carboxyl-terminal fragment (817-1314) possesses a conserved putative nuclear localization signal that I found is needed to facilitate delta-cateninā€™s nuclear targeting. To probe for novel nuclear roles of delta-catenin, I performed yeast two-hybrid screening of a mouse brain cDNA library, resolving and then validating its interaction with an uncharacterized KRAB family zinc finger protein I named ZIFCAT. My results indicate that ZIFCAT is nuclear, and suggest that it may associate with DNA as a transcriptional repressor. I further determined that other p120 sub-class catenins are similarly cleaved by caspase-3, and likewise bind ZIFCAT. These findings potentially reveal a simple yet novel signaling pathway based upon caspase-3 cleavage of p120 sub-family members, facilitating the coordinate modulation of cadherins, small GTPases and nuclear functions. Together, my work suggested delta-cateninā€™s essential roles in Xenopus development, and has revealed its novel contributions to cell junctions (via cadherins), cytoskeleton (via small G proteins), and nucleus (via ZIFCAT). Future questions include the larger role and gene targets of delta-catenin in nucleus, and identification of upstream signaling events controlling delta-cateninā€™s activities in development or disease progression

    Junctional Music that the Nucleus Hears: Cellā€“Cell Contact Signaling and the Modulation of Gene Activity

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    Cellā€“cell junctions continue to capture the interest of cell and developmental biologists, with an emerging area being the molecular means by which junctional signals relate to gene activity in the nucleus. Although complexities often arise in determining the direct versus indirect nature of such signal transduction, it is clear that such pathways are essential for the function of tissues and that alterations may contribute to many pathological outcomes. This review assesses a variety of cellā€“cell junction-to-nuclear signaling pathways, and outlines interesting areas for further study
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