748 research outputs found
Antioxidative Activities of Alfalfa and Timothy Varieties
The term functional foods is often used as a generic description for the beneficial effects of ingested foods that go beyond their traditional nutritive value (Bauman et al., 2001). Milk and dairy products are important dietary sources of nutrients, providing energy, high quality protein, and a variety of vitamins and minerals. Recent research has focused on altering the fat and protein content of milk and other dairy products in order to improve their nutrient content to more aptly reflect current dietary recommendations and trends. As a result, additional focus is being given to designing foods that have beneficial effects on human health. This study was carried out to investigate the antioxidative activities of forages grown in Korea
Yield and Nutritive Value of Heading and Headless Sorghum x Sudangrass Hybrids in Response to Cutting Frequency
Summer annual forages contribute greatly toward solving the problem of roughage supply for cattle in Korea. These forages support high levels of dairy and beef production during hot summer months when the quality and production of perennial herbage decreases due to unfavourable climatic conditions (Olson, 1971). This study investigated the effects of cutting frequency on dry matter (DM) yield and nutritive value of heading versus headless varieties of sorghum x sudangrass hybrid
Arabidopsis ABCG34 contributes to defense against necrotrophic pathogens by mediating the secretion of camalexin
Plant pathogens cause huge yield losses. Plant defense often depends on toxic secondary metabolites that inhibit pathogen growth. Because most secondary metabolites are also toxic to the plant, specific transporters are needed to deliver them to the pathogens. To identify the transporters that function in plant defense, we screened Arabidopsis thaliana mutants of full-size ABCG transporters for hypersensitivity to sclareol, an antifungal compound. We found that atabcg34 mutants were hypersensitive to sclareol and to the necrotrophic fungi Alternaria brassicicola and Botrytis cinerea. AtABCG34 expression was induced by A. brassicicola inoculation as well as by methyl-jasmonate, a defense-related phytohormone, and AtABCG34 was polarly localized at the external face of the plasma membrane of epidermal cells of leaves and roots. atabcg34 mutants secreted less camalexin, a major phytoalexin in A. thaliana, whereas plants overexpressing AtABCG34 secreted more camalexin to the leaf surface and were more resistant to the pathogen. When treated with exogenous camalexin, atabcg34 mutants exhibited hypersensitivity, whereas BY2 cells expressing AtABCG34 exhibited improved resistance. Analyses of natural Arabidopsis accessions revealed that AtABCG34 contributes to the disease resistance in naturally occurring genetic variants, albeit to a small extent. Together, our data suggest that AtABCG34 mediates camalexin secretion to the leaf surface and thereby prevents A. brassicicola infection.117Ysciescopu
THE TRANSFORMATIVE POTENTIAL OF CREATIVE ART PRACTICES IN THE CONTEXT OF INTERDISCIPLINARY RESEARCH
A growing body of literature addressing the need for educational innovations has also stressed the value of interdisciplinary approaches that incorporate art into teaching and learning. This paper aims to extend educators??? understanding of art???science interactions by presenting an empirical study that explores a unique art residency program created on the campus of a university that specializes in science and technology. The study reviews the art practices of three contemporary artists who participated in a program developed in conjunction with an interdisciplinary research project seeking ways to build an ecologically sustainable community and operated by a renewable energy resource-based economic system. Data that include observations, artist talks, and in-person interviews were collected from multiple sources during the residency to understand the distinguished processes involved in the development of individual art projects. A follow-up cross-case analysis revealed a few notable characteristics: connecting art with life through waste recycling, process-oriented practices highlighting resource circulation, and creating value using bricolage strategies. Regarding educational implications, discussions centered upon the potential transformational space identified from the creative art practices in the context of interdisciplinary research
Effect of the GaAsP shell on optical properties of self-catalyzed GaAs nanowires grown on silicon
We realize growth of self-catalyzed core-shell GaAs/GaAsP nanowires (NWs) on
Si substrates using molecular-beam epitaxy. Transmission electron microscopy
(TEM) of single GaAs/GaAsP NWs confirms their high crystal quality and shows
domination of the zinc-blende phase. This is further confirmed in optics of
single NWs, studied using cw and time-resolved photoluminescence (PL). A
detailed comparison with uncapped GaAs NWs emphasizes the effect of the GaAsP
capping in suppressing the non-radiative surface states: significant PL
enhancement in the core-shell structures exceeding 2000 times at 10K is
observed; in uncapped NWs PL is quenched at 60K whereas single core-shell
GaAs/GaAsP NWs exhibit bright emission even at room temperature. From analysis
of the PL temperature dependence in both types of NW we are able to determine
the main carrier escape mechanisms leading to the PL quench
The Rice SPOTTED LEAF4 (SPL4) Encodes a Plant Spastin That Inhibits ROS Accumulation in Leaf Development and Functions in Leaf Senescence
Lesion mimic mutants (LMMs) are usually controlled by single recessive mutations that cause the formation of necrotic lesions without pathogen invasion. These genetic defects are useful to reveal the regulatory mechanisms of defense-related programmed cell death in plants. Molecular evidence has been suggested that some of LMMs are closely associated with the regulation of leaf senescence in rice (Oryza sativa). Here, we characterized the mutation underlying spotted leaf4 (spl4), which results in lesion formation and also affects leaf senescence in rice. Map-based cloning revealed that the gamma ray-induced spl4-1 mutant has a single base substitution in the splicing site of the SPL4 locus, resulting in a 13-bp deletion within the encoded microtubule-interacting-and-transport (MIT) spastin protein containing an AAA-type ATPase domain. The T-DNA insertion spl4-2 mutant exhibited spontaneous lesions similar to those of the spl4-1 mutant, confirming that SPL4 is responsible for the LMM phenotype. In addition, both spl4 mutants exhibited delayed leaf yellowing during dark-induced or natural senescence. Western blot analysis of spl4 mutant leaves suggested possible roles for SPL4 in the degradation of photosynthetic proteins. Punctate signals of SPL4-fused fluorescent proteins were detected in the cytoplasm, similar to the cellular localization of animal spastin. Based on these findings, we propose that SPL4 is a plant spastin that is involved in multiple aspects of leaf development, including senescence
Deciphering the unusual stellar progenitor of GRB 210704A
GRB~210704A is a burst of intermediate duration (~s)
followed by a fading afterglow and an optical excess that peaked about 7 days
after the explosion. Its properties, and in particular those of the excess, do
not easily fit into the well established classification scheme of GRBs as being
long or short, leaving the nature of its progenitor uncertain. We present
multi-wavelength observations of the GRB and its counterpart, observed up to
160 days after the burst. In order to decipher the nature of the progenitor
system, we present a detailed analysis of the GRB high-energy properties
(duration, spectral lag, and Amati correlation), its environment, and late-time
optical excess. We discuss three possible scenarios: a neutron star merger, a
collapsing massive star, and an atypical explosion possibly hosted in a cluster
of galaxies. We find that traditional kilonova and supernova models do not
match well the properties of the optical excess, leaving us with the intriguing
suggestion that this event was an exotic high-energy merger.Comment: Revised version submitted to MNRAS after minor comments, 14 pages, 9
figure
The nuclear immune receptor RPS4 is required for RRS1SLH1-dependent constitutive defense activation in Arabidopsis thaliana
Plant nucleotide-binding leucine-rich repeat (NB-LRR) disease resistance (R) proteins recognize specific ‘‘avirulent’’ pathogen effectors and activate immune responses. NB-LRR proteins structurally and functionally resemble mammalian Nod-like receptors (NLRs). How NB-LRR and NLR proteins activate defense is poorly understood. The divergently transcribed Arabidopsis R genes, RPS4 (resistance to Pseudomonas syringae 4) and RRS1 (resistance to Ralstonia solanacearum 1), function together to confer recognition of Pseudomonas AvrRps4 and Ralstonia PopP2. RRS1 is the only known recessive NBLRR R gene and encodes a WRKY DNA binding domain, prompting suggestions that it acts downstream of RPS4 for transcriptional activation of defense genes. We define here the early RRS1-dependent transcriptional changes upon delivery of PopP2 via Pseudomonas type III secretion. The Arabidopsis slh1 (sensitive to low humidity 1) mutant encodes an RRS1 allele (RRS1SLH1) with a single amino acid (leucine) insertion in the WRKY DNA-binding domain. Its poor growth due to constitutive defense activation is rescued at higher temperature. Transcription profiling data indicate that RRS1SLH1-mediated defense activation overlaps substantially with AvrRps4- and PopP2-regulated responses. To better understand the genetic basis of RPS4/RRS1-dependent immunity, we performed a genetic screen to identify suppressor of slh1 immunity (sushi) mutants. We show that many sushi mutants carry mutations in RPS4, suggesting that RPS4 acts downstream or in a complex with RRS1. Interestingly, several mutations were identified in a domain C-terminal to the RPS4 LRR domain. Using an Agrobacterium-mediated transient assay system, we demonstrate that the P-loop motif of RPS4 but not of RRS1SLH1 is required for RRS1SLH1 function. We also recapitulate the dominant suppression of RRS1SLH1 defense activation by wild type RRS1 and show this suppression requires an intact RRS1 P-loop. These analyses of RRS1SLH1 shed new light on mechanisms by which NB-LRR protein pairs activate defense signaling, or are held inactive in the absence of a pathogen effector
A Two-dimensional Analytical Model for Prediction of the Radiation Heat Transfer in Open-cell Metal Foams
This is the accepted manuscript version of the following article: "Z. Jiang, et al., “A two-dimensional analytical model for prediction of the radiation heat transfer in open-cell metal foams”, Applied Thermal Engineering, Vol. 93: 1273-1281, October 2015." The final published version is available at: https://doi.org/10.1016/j.applthermaleng.2015.09.043 Copyright © 2015 Elsevier Ltd. All rights reserved. Article under Embargo until 23/10/17.In this article, a new two-dimensional (2D) explicit analytical model for the evaluation of the radiation heat transfer in highly porous open-cell metal foams is formulated and validated. A correction factor, C, is introduced to correct the deviation of the specific area in a simplified manner. Numerical results are compared with the published experimental data and three-dimensional (3D) model proposed in previous works. It reveals that the present two-dimensional model is proved to be relatively accurate in estimating the radiative conductivity for all the investigated structures. In the current work, the effects of the control parameters, such as the number of order in the iterative procedure, solid emissivity, the temperature difference, shape of solid particle and correction factor on the predictions of radiation characteristics are well discussed.Peer reviewe
Ni(OH)2 Nanoplates Grown on Graphene as Advanced Electrochemical Pseudocapacitor Materials
Ni(OH)2 nanocrystals grown on graphene sheets with various degrees of
oxidation are investigated as electrochemical pseudocapacitor materials for
potential energy storage applications. Single-crystalline Ni(OH)2 hexagonal
nanoplates directly grown on lightly-oxidized, electrically-conducting graphene
sheets (GS) exhibit a high specific capacitance of ~1335F/g at a charge and
discharge current density of 2.8A/g and ~953F/g at 45.7A/g with excellent
cycling ability. The high specific capacitance and remarkable rate capability
are promising for applications in supercapacitors with both high energy and
power densities. Simple physical mixture of pre-synthesized Ni(OH)2 nanoplates
and graphene sheets show lower specific capacitance, highlighting the
importance of direct growth of nanomaterials on graphene to impart intimate
interactions and efficient charge transport between the active nanomaterials
and the conducting graphene network. Single-crystalline Ni(OH)2 nanoplates
directly grown on graphene sheets also significantly outperform small Ni(OH)2
nanoparticles grown on heavily-oxidized, electrically-insulating graphite oxide
(GO), suggesting that the electrochemical performance of these composites are
dependent on the quality of graphene substrates and the morphology and
crystallinity of the nanomaterials grown on top. These results suggest the
importance of rational design and synthesis of graphene-based nanocomposite
materials for high-performance energy applications.Comment: Published in JAC
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