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  • 1
    Language: English
    In: Journal of the American Chemical Society, 08 May 2013, Vol.135(18), pp.6806-9
    Description: The synthesis and characterization of atactic and isotactic linear poly(benzyl 1,2-glycerol carbonate)s are reported. The poly(benzyl 1,2-glycerol carbonate)s were obtained via the ring-opening copolymerization of rac-/(R)-benzyl glycidyl ether with CO2 using [SalcyCo(III)X] complexes with high carbonate linkage selectivity and polymer/cyclic carbonate selectivity (〉99%). Deprotection of the resultant polymers afforded poly(1,2-glycerol carbonate)s with a functionalizable pendant primary hydroxyl group. Poly(1,2-glycerol carbonate) showed a remarkable increase in degradation rate compared to poly(1,3-glycerol carbonate) with a t1/2 ≈ 2-3 days. These polymers fulfill an unmet need for a readily degradable biocompatible polycarbonate.
    Keywords: Biocompatible Materials -- Chemical Synthesis ; Pharmaceutical Preparations -- Chemical Synthesis ; Polyesters -- Chemical Synthesis
    ISSN: 00027863
    E-ISSN: 1520-5126
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  • 2
    In: Journal of Applied Polymer Science, 05 March 2014, Vol.131(5), pp.n/a-n/a
    Description: The terpolymerization of benzyl glycidyl ether (BGE), propylene oxide (PO), and CO using both a binary [‐SalcyCoDNP]/PPNDNP system and a bifunctional [‐SalcyCoDNP] catalyst bearing a quaternary ammonium salt is reported. Catalyst activities range from 149 to 563 h for the binary catalyst at the various monomer feeding ratios. The bifunctional catalyst shows increased activity up to 857 h at higher temperature with slightly compromised polymer selectivity. The percentage of BGE or PO incorporation in the polymer chain reflects the initial feeding ratio and remains constant during the course of the reaction. A Fineman‐Ross plot determined the monomer reactivity ratio to be 1.15 and 0.93 for BGE and PO, respectively. The glass transition temperature of the terpolymers is dependent on 1,2‐glycerol carbonate (GC) content and decreases from 37 to 8°C with increasing GC content. The decomposition temperature at 5% weight loss also shows a similar dependency, and varies from 233 to 269°C. The benzyl protecting group is removed using H and Pd/C to afford the poly(1,2‐glycerol‐‐propylene carbonate)s (PGC‐‐PC). The glass transition and decomposition temperatures as well as the mechanical properties are lower for the PGC‐‐PCs compared with the corresponding values for the poly(benzyl 1,2‐glycerol‐‐propylene carbonate)s. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., , , 39893.
    Keywords: Biopolymers And Renewable Polymers ; Biomaterials ; Polycarbonates
    ISSN: 0021-8995
    E-ISSN: 1097-4628
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  • 3
    Language: English
    In: Tourism Management, August 2012, Vol.33(4), pp.916-925
    Description: Ecotourism supports environmental conservation as well as generating economic opportunities. It additionally strongly emphasizes benefits to the local community and suggests that the involvement of the residents is important for the effective management of tourism. Accordingly, this study explores factors contributing to residents’ participation intention in ecotourism management and proposes a structural relationship between their participation intention, environmental knowledge, attitudes towards ecotourism and the appeal of tourist landscapes. Analysis indicates residents’ environmental knowledge positively affects attitudes towards ecotourism, which in turn directly and indirectly determine the intention to participate in ecotourism through their individual landscape affinity. Thus, residents’ involvement in ecotourism may be stimulated through a) appropriate management strategies aimed at increasing their environmental knowledge, b) encouraging positive ecotourism attitudes, and c) environmental planning that promotes residents’ affinity for local attractions. ► Environmental knowledge, through ecotourism attitudes, promotes participation intention. ► Landscape likeability mediates between ecotourism attitudes and participation intention. ► Landscape likeability contributes to local tourism management. ► Programs increasing environmental knowledge and landscape likeability inspire participation.
    Keywords: Participation Intention ; Ecotourism Attitudes ; Landscape Likeability ; Environmental Knowledge ; Geography ; Business
    ISSN: 0261-5177
    E-ISSN: 1879-3193
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  • 4
    Language: English
    In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, Jan 20, 2013, Vol.417, p.217(7)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.colsurfa.2012.10.066 Byline: Heng Zhang, Hua Wang, Guiying Xu, Shiling Yuan Abstract: Display Omitted Author Affiliation: Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan 250100, China Article History: Received 2 July 2012; Accepted 31 October 2012
    ISSN: 0927-7757
    Source: Cengage Learning, Inc.
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  • 5
    Language: English
    In: Plant physiology, May 2012, Vol.159(1), pp.418-32
    Description: In Arabidopsis (Arabidopsis thaliana), the ATP-dependent chromatin remodeler PICKLE (PKL) determines expression of genes associated with developmental identity. PKL promotes the epigenetic mark trimethylation of histone H3 lysine 27 (H3K27me3) that facilitates repression of tissue-specific genes in plants. It has previously been proposed that PKL acts indirectly to promote H3K27me3 by promoting expression of the POLYCOMB REPRESSIVE COMPLEX2 complex that generates H3K27me3. We undertook expression and chromatin immunoprecipitation analyses to further characterize the contribution of PKL to gene expression and developmental identity. Our expression data support a critical and specific role for PKL in expression of H3K27me3-enriched loci but do not support a role for PKL in expression of POLYCOMB REPRESSIVE COMPLEX2. Moreover, our chromatin immunoprecipitation data reveal that PKL protein is present at the promoter region of multiple H3K27me3-enriched loci, indicating that PKL directly acts on these loci. In particular, we find that PKL is present at LEAFY COTYLEDON1 and LEAFY COTYLEDON2 during germination, which is when PKL acts to repress these master regulators of embryonic identity. Surprisingly, we also find that PKL is present at the promoters of actively transcribed genes that are ubiquitously expressed such as ACTIN7 and POLYUBIQUITIN10 that do not exhibit PKL-dependent expression. Taken together, our data contravene the previous model of PKL action and instead support a direct role for PKL in determining levels of H3K27me3 at repressed loci. Our data also raise the possibility that PKL facilitates a common chromatin remodeling process that is not restricted to H3K27me3-enriched regions.
    Keywords: Arabidopsis -- Metabolism ; Arabidopsis Proteins -- Metabolism ; Histones -- Metabolism
    ISSN: 00320889
    E-ISSN: 1532-2548
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  • 6
    In: Chemical Communications, 2014, Vol.50(17), pp.2193-2195
    Description: Palladium-catalyzed arylation of (diisopropylphosphoryl)biphenyl skeleton derivatives by the P(O)R 2 directed CH functionalization was reported. The related products were obtained in high regioselectivity and good functional group tolerance was observed. This reaction provided a new and efficient pathway for the synthesis of polyaromatic monophosphorus ligands.
    Keywords: Derivatives ; Pathways ; Tolerances ; Synthesis ; Ligands ; Functional Groups ; Miscellaneous Sciences (So) ; Components and Materials (General) (Ea) ; Surveying, Theory, and Analysis (CE);
    ISSN: 1359-7345
    E-ISSN: 1364-548X
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  • 7
    Language: English
    In: Advanced Materials, 12 July 2013, Vol.25(26), pp.3543-3548
    Description: displays humidity‐induced phase transitions from a hexagonal columnar structure to a bicontinuous cubic phase. The mesophases can be frozen by photopolymerization of acrylic end‐groups resulting in free‐standing membranes with different topology of ionic nanochannels. The obtained membranes with a well‐ordered ionic channel structure hold promise for applications in separation and catalysis.
    Keywords: Ionic Channels ; Bicontinuous Cubic Phase ; Columnar Mesophase ; Self‐Assembly ; Ion‐Conducting Membranes
    ISSN: 0935-9648
    E-ISSN: 1521-4095
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  • 8
    In: Stroke, 2012, Vol.43(1), pp.e4-e4
    Description: To the Editor: I read with great interest the prospective study1 that argued that the diabetes mellitus (DM) independently predicted poor outcomes after acute ischemic stroke in Chinese people. Unfortunately, the conclusion of the study might be debatable due to the inappropriate definition of patients as having DM. The author classified patients as having DM when: “a self-reported physician diagnosis of DM, use of hypoglycemic medications (for example, insulin or sulfonylureas) during hospitalization, or hypoglycemic medication use at discharge.”1 Actually, the …
    Keywords: Medicine;
    ISSN: 0039-2499
    E-ISSN: 15244628
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  • 9
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 14 May 2013, Vol.110(20), pp.8290-5
    Description: DNA methylation is an important epigenetic mark in many eukaryotic organisms. De novo DNA methylation in plants can be achieved by the RNA-directed DNA methylation (RdDM) pathway, where the plant-specific DNA-dependent RNA polymerase IV (Pol IV) transcribes target sequences to initiate 24-nt siRNA production and action. The putative DNA binding protein DTF1/SHH1 of Arabidopsis has been shown to associate with Pol IV and is required for 24-nt siRNA accumulation and transcriptional silencing at several RdDM target loci. However, the extent and mechanism of DTF1 function in RdDM is unclear. We show here that DTF1 is necessary for the accumulation of the majority of Pol IV-dependent 24-nt siRNAs. It is also required for a large proportion of Pol IV-dependent de novo DNA methylation. Interestingly, there is a group of RdDM target loci where 24-nt siRNA accumulation but not DNA methylation is dependent on DTF1. DTF1 interacts directly with the chromatin remodeling protein CLASSY 1 (CLSY1), and both DTF1 and CLSY1 are associated in vivo with Pol IV but not Pol V, which functions downstream in the RdDM effector complex. DTF1 and DTF2 (a DTF1-like protein) contain a SAWADEE domain, which was found to bind specifically to histone H3 containing H3K9 methylation. Taken together, our results show that DTF1 is a core component of the RdDM pathway, and suggest that DTF1 interacts with CLSY1 to assist in the recruitment of Pol IV to RdDM target loci where H3K9 methylation may be an important feature. Our results also suggest the involvement of DTF1 in an important negative feedback mechanism for DNA methylation at some RdDM target loci.
    Keywords: Gene Silencing ; Histone Modifications ; Small RNA ; Transposon ; DNA Methylation ; Arabidopsis -- Genetics ; Arabidopsis Proteins -- Metabolism ; DNA Polymerase Beta -- Metabolism ; Homeodomain Proteins -- Metabolism ; RNA-Directed DNA Polymerase -- Metabolism
    ISSN: 00278424
    E-ISSN: 1091-6490
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  • 10
    Language: English
    In: Journal of the American Chemical Society, 01 December 2010, Vol.132(47), pp.16737-40
    Description: A striking breakthrough to the frame of traditional cross-couplings/C-H functionalizations using an organocatalyst remains unprecedented. We uncovered a conceptually different approach toward the biaryl syntheses by using DMEDA as the catalyst to promote the direct C-H arylation of unactivated benzene in the presence of potassium tert-butoxide. The arylation of unactivated benzene with aryl iodides, or aryl bromides and even chlorides under the assistance of an iodo-group, could simply take place at 80 °C. The new methodology presumably involves an aryl radical anion as an intermediate. This finding offers an option toward establishing a new horizon for direct C-H/cross-coupling reactions.
    Keywords: Benzene -- Chemistry ; Carbon -- Chemistry ; Ethylenediamines -- Chemistry ; Hydrogen -- Chemistry
    ISSN: 00027863
    E-ISSN: 1520-5126
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