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  • 1
    Language: English
    In: Plant physiology, August 2011, Vol.156(4), pp.1905-20
    Description: Despite the accumulation of data on the genetic and molecular understanding of heterosis, there is little information on the regulation of heterosis at the physiological level. In this study, we performed a quantitative analysis of endogenous gibberellin (GA) content and expression profiling of the GA metabolism and signaling genes to investigate the possible relationship between GA signaling and heterosis for seedling development in rice (Oryza sativa). The materials used were an incomplete diallele set of 3 × 3 crosses and the six parents. In the growing shoots of the seedlings at 20 d after sowing, significant positive correlations between the contents of some GA species and performance and heterosis based on shoot dry mass were detected. Expression analyses of GA-related genes by real-time reverse transcription-polymerase chain reaction revealed that 13 out of the 16 GA-related genes examined exhibited significant differential expression among the F1 hybrid and its parents, acting predominantly in the modes of overdominance and positive dominance. Expression levels of nine genes in the hybrids displayed significant positive correlations with the heterosis of shoot dry mass. These results imply that GAs play a positive role in the regulation of heterosis for rice seedling development. In shoots plus root axes of 4-d-old germinating seeds that had undergone the deetiolation, mimicking normal germination in soil, the axis dry mass was positively correlated with the content of GA₂₉ but negatively correlated with that of GA₁₉. Our findings provide supporting evidence for GAs playing an important regulatory role in heterosis for rice seedling development.
    Keywords: Gene Expression Regulation, Plant ; Gibberellins -- Metabolism ; Hybrid Vigor -- Genetics ; Oryza -- Genetics ; Seedlings -- Genetics ; Signal Transduction -- Genetics
    ISSN: 00320889
    E-ISSN: 1532-2548
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  • 2
    Language: English
    In: Polymer, 12 September 2011, Vol.52(20), pp.4562-4570
    Description: The nanoscale phase behavior of a semicrystalline polymer is important for mechanical, thermal, optical and other macroscopic properties and can be analyzed well by thermal methods. Using quasi-isothermal (QI) heat capacity measurements, we investigate the formation behavior of the crystalline, mobile amorphous, and rigid amorphous fractions in poly(trimethylene terephthalate), PTT. The crystal and rigid amorphous phases comprise the total solid fraction in PTT at temperatures above , the glass transition temperature of the mobile amorphous fraction. PTT was quasi-isothermally cooled step-wise from the melt which causes its crystalline fraction to be fixed below 451 K. Between the high temperature fulfillment of the step and 451 K, the temperature dependent rigid amorphous fraction (RAF) is completely determined. For PTT, most of the RAF vitrifies between 451 K and step by step during QI cooling after the crystals have formed. The constraints imposed by the crystal surfaces reduce the mobility of the highly entangled polymer chains. We suggest the vitrification of RAF proceeds outward away from the lamellar surfaces in a step by step manner during QI cooling. Upon reheating, devitrification of RAF occurs at a temperature above its previous vitrification temperature, due to the effects of densification brought by physical aging during the long period of quasi-isothermal treatment. Finally, we consider recent concepts related to jamming, which have been suggested to apply to filled polymer systems, and may also be applicable in describing constraints exerted by crystal lamellae upon the RAF.
    Keywords: Poly(Trimethylene Terephthalate) ; Quasi-Isothermal Calorimetry ; Constrained Amorphous Phase ; Engineering ; Chemistry
    ISSN: 0032-3861
    E-ISSN: 1873-2291
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  • 3
    Language: English
    In: Polymer, 26 April 2013, Vol.54(10), pp.2544-2554
    Description: We investigated the molecular orientation, crystallization mechanism, phase structure and transitions of aligned electrospun fibers, including the constrained amorphous phase and its relationship to the mesophase. Aligned poly(lactic acid) (PLA) fibers were successfully electrospun (ES) by adopting a high-speed rotating wheel as the counter electrode. Using thermal analysis and wide angle X-ray scattering (WAXS), we evaluated the confinement that exists in as-spun amorphous, and heat-treated semicrystalline, fibers. Differential scanning calorimetry confirmed the existence of a constrained amorphous phase in as-spun aligned fibers, without the presence of crystals or fillers to serve as fixed physical constraints. Then, using WAXS, for the first time the mesophase fraction, consisting of oriented non-crystalline PLA chains, was quantitatively characterized in PLA nanofibers. The formation of oriented crystals during subsequent heating, and the evolution of the phase fractions (crystal, mobile amorphous, and constrained amorphous) with temperature, were investigated as to their dependence upon the method of fixing the ends of the fibers. In ES nanofibers, the mesophase does not directly transition into the crystal phase of higher packing order. Instead, at temperatures above , the fiber undergoes residual stress relaxation, accompanied by the devitrification of the mesophase from a confined solid state to a mobile liquid state. The mesophase, which possesses some degree of medium-range order, behaves very similarly to the rigid amorphous phase, and a correlation between the two is established in fibers. On the other hand, for as-spun fibers, the mesophase forms a more ordered structure when heated. By fixing the fiber ends, relaxation of the mesophase above is partially disabled. The more ordered mesophase that survives above undergoes a mesophase-to-crystal phase transition upon further heating, making an additional contribution to the heat of fusion. A new phase structure model is proposed to describe aligned electrospun PLA nanofibers.
    Keywords: Electrospun Nanofiber ; Rigid Amorphous Phase ; Mesophase ; Engineering ; Chemistry
    ISSN: 0032-3861
    E-ISSN: 1873-2291
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  • 4
    Language: English
    In: Plant physiology, December 2012, Vol.160(4), pp.1968-84
    Description: The factors that mediate specific responses to the plant hormone ethylene are not fully defined. In particular, it is not known how signaling at the receptor complex can control distinct subsets of ethylene responses. Mutations at the Green-ripe (Gr) and reversion to ethylene sensitivity1 (rte1) loci, which encode homologous proteins of unknown function, influence ethylene responses in tomato (Solanum lycopersicum) and Arabidopsis (Arabidopsis thaliana), respectively. In Arabidopsis, AtRTE1 is required for function of the ETR1 ethylene receptor and acts predominantly through this receptor via direct protein-protein interaction. While most eudicot families including the Brassicaceae possess a single gene that is closely related to AtRTE1, we report that members of the Solanaceae family contain two phylogenetically distinct genes defined by GR and GREEN-RIPE LIKE1 (GRL1), creating the possibility of subfunctionalization. We also show that SlGR and SlGRL1 are differentially expressed in tomato tissues and encode proteins predominantly localized to the Golgi. A combination of overexpression in tomato and complementation of the rte1-3 mutant allele indicates that SlGR and SlGRL1 influence distinct but overlapping ethylene responses. Overexpression of SlGRL1 in the Gr mutant background provides evidence for the existence of different ethylene signaling modules in tomato that are influenced by GR, GRL1, or both. In addition, overexpression of AtRTE1 in tomato leads to reduced ethylene responsiveness in a subset of tissues but does not mimic the Gr mutant phenotype. Together, these data reveal species-specific heterogeneity in the control of ethylene responses mediated by members of the GR/RTE1 family.
    Keywords: Ethylenes -- Pharmacology ; Genes, Plant -- Genetics ; Lycopersicon Esculentum -- Genetics ; Plant Proteins -- Genetics ; Signal Transduction -- Drug Effects
    ISSN: 00320889
    E-ISSN: 1532-2548
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  • 5
    Language: English
    In: Journal of Crystal Growth, 15 September 2012, Vol.355(1), pp.73-77
    Description: The characteristics of heterogeneous nucleation on concave spherical surfaces were analysed using a novel analytical approach and compared with nucleation on both convex and planar surfaces. The complex expressions of ( : free energy change and : embryo radius) for nucleation on concave spherical surfaces can be reduced to the simple form for nucleation on planar surfaces by introducing an appropriate pseudo-contact angle, providing a new fundamental link. The advantages of heterogeneous nucleation on a concave spherical surface of radius R over a planar surface occur primarily when 2 〈10 ⁎ ( *: nucleus radius) and diminish rapidly when 2 〉10 *. This is similar to nucleation on convex spherical surfaces, where the disadvantages of nucleation over a planar surface occur primarily when 2 〈10 * and diminish rapidly when 2 〉10 *. The substrate size 10 * thus provides an approximate borderline that distinguishes between curved and planar surfaces for nucleation. The advantages or disadvantages of nucleation over a planar surface are most outstanding when the concave (advantageous) or convex (disadvantageous) surface shows a specific contact angle with the nucleus. The nanoscale nature of the threshold size 10 * presents a clear fundamental support to surface nanopatterning for directed nucleation. A minimum depth is required for a nanoscale crater to be a favourable nucleation site. ► We report a new fundamental link for nucleation on concave, convex and flat surfaces. ► The advantages of nucleation on concave surfaces of radius R occur primarily when 2 〈10 . ► The threshold 10 provides a clear fundamental support to surface nanopatterning. ► Craters with 2 〈10 and a minimum depth are most desired for nucleation.
    Keywords: A1. Nucleation ; A1. Surfaces ; A1. Surface Structure ; A1. Surface Processes ; A1. Roughening ; Engineering ; Chemistry
    ISSN: 0022-0248
    E-ISSN: 1873-5002
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  • 6
    Language: English
    In: Journal of the American College of Cardiology, 18 October 2016, Vol.68(16), pp.C49-C49
    Description: Nanoparticles can provide a variety of delivery systems which can increase drug concentrations in targeted tissues, improve the efficiency of drugs, decrease the required dosage, reduce the side-effects of oral administration.
    Keywords: Medicine
    ISSN: 0735-1097
    E-ISSN: 1558-3597
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  • 7
    In: RSC Advances, 2015, Vol.5(16), pp.12323-12328
    Description: Oxynitride phosphors Sr 6 Si 25.6 x Al 6.4+ x N 41.6 x O 4.4+ x :Eu 2+ are synthesized by gas pressure sintering of powder mixture of SrCO 3 , AlN, Si 3 N 4 and Eu 2 O 3 at 1800 C and 0.5 MPa of N 2 for 10 h, and their photoluminescence properties are investigated. Sr 6 Si 25.6 x Al 6.4+ x N 41.6 x O 4.4+ x :Eu 2+ can be efficiently excited over a broad spectral range between 300 and 500 nm, and exhibit an intense green emission centered at about 515 nm with a full width at half maximum of 65 nm due to the 4f 6 5d 1 4f 7 transition of Eu 2+ ions. The influence of the replacement of SiN by AlO on luminescence properties and crystal structure is reported in a series of Sr 6 Si 25.6 x Al 6.4+ x N 41.6 x O 4.4+ x :Eu 2+ phosphors. Different Sr sites are found in the crystal structure. The thermal quenching properties of the green phosphors are better than that of typical orthosilicate Ba 2 SiO 4 :Eu 2+ phosphor. Their interesting photoluminescence properties indicate that the Sr 6 Si 25.6 Al 6.4 N 41.6 O 4.4 phosphor is a promising green emitting candidate for white LEDs applications.
    Keywords: Algorithms – Analysis;
    ISSN: 2046-2069
    ISSN: 09345043
    E-ISSN: 2046-2069
    E-ISSN: 10974628
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  • 8
    Language: English
    In: Journal of the American College of Cardiology, 20 October 2015, Vol.66(16), pp.C104-C104
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jacc.2015.06.404 Byline: Changlong Li, Zhijian Wang, Chunxiao Wang, Qian Ma, Yingxin Zhao Author Affiliation: (1) Beijing Institute of Heart Lung and Blood Vessel Diseases (2) Department of Cardiology, Anzhen Hospital, Capital Medical University
    Keywords: Medicine
    ISSN: 0735-1097
    E-ISSN: 1558-3597
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  • 9
    Language: English
    In: Neurocomputing, June 10, 2014, Vol.133, p.399(5)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.neucom.2013.12.034 Byline: Qian Ma, Guoying Miao Abstract: This paper investigates the distributed containment control problem for linear multi-agent systems. Distributed dynamic output feedback controllers on the basis of the relative outputs of neighboring agents are proposed. Necessary and sufficient containment control conditions are presented which are less conservative than those in the literature. These conditions depend on the spectral properties of the topology matrix. Effective algorithms are proposed to obtain control gain matrices based on H.sub.[infinity] type Riccati design. Then, distributed static output feedback control method is also discussed. Simulation examples are provided finally to demonstrate the effectiveness of the proposed design methods. Author Affiliation: (a) School of Automation, Nanjing University of Science and Technology, Nanjing 210094, PR China (b) School of Information and Control, Nanjing University of Information Science and Technology, Nanjing 210044, PR China Article History: Received 24 July 2013; Revised 6 October 2013; Accepted 8 December 2013 Article Note: (miscellaneous) Communicated by Hongyi Li
    Keywords: Algorithms
    ISSN: 0925-2312
    Source: Cengage Learning, Inc.
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  • 10
    Language: English
    In: Applied Surface Science, 01 October 2012, Vol.258(24), pp.9711-9717
    Description: ► Cell membrane mimetic antifouling polymer brush was grown on polysulfone surface. ► Graft density and polymerization degree were calculated from XPS results. ► Water contact angle measurements showed an extremely hydrophilic surface. ► Platelet adhesion and protein adsorption results suggested excellent antifouling ability. Cell membrane mimetic antifouling polymer brush was grown on polysulfone (PSF) membrane by surface-induced reversible addition–fragmentation chain transfer (RAFT) polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC). The RAFT agent immobilized PSF substrate was prepared by successive chloromethylation, amination with ethylenediamine (EDA) and amidation of the amine group of grafted EDA with the carboxylic group of 4-cyanopentanoic acid dithiobenzoate (CPAD). The surface RAFT polymerization of MPC was initiated in aqueous solution by 4,4′-azobis-4-cyanopentanoic acid (ACPA). The formation of PMPC brush coating is evidenced by X-ray photoelectron spectroscopy and water contact angle measurements. The degree of polymerization of PMPC and the polymer grafting density were calculated from the high resolution XPS spectra. The platelet adhesion and protein adsorption results showed that the PMPC-grafted PSF surface has excellent antifouling ability to resist platelet adhesion completely and suppress protein adsorption significantly. This biomimetic and bio-friendly surface RAFT polymerization strategy could be promising for a variety of biomedical applications.
    Keywords: Surface Modification ; Phosphorylcholine ; Raft Polymerization ; Antifouling Surface ; Polysulfone ; Engineering
    ISSN: 0169-4332
    E-ISSN: 1873-5584
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