1,044 research outputs found

    Using agronomic biofortification to boost zinc, selenium, and iodine concentrations of food crops grown on the loess plateau in China

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    Micronutrient malnutrition among humans is typically caused by micronutrient deficiency in soils and then staple food crops grown on these soils. In this study, field trials were conducted to investigate the biofortification of micronutrients in the edible parts of winter wheat, maize, soybean, potato, canola, and cabbage. Fertilizers of Se, Zn and I were applied to soil independently or together, while Se and Zn were sprayed as solution on winter wheat in another part of the trials. Selenium, when applied to the soil in the form of sodium selenate, whether alone or combined with Zn andā„or I, was effective in increasing Se to around target levels in all of the tested crops. Selenium as sodium selenite was effective as a foliar application to winter wheat, increasing it from 25 to 312 Āµg kgā»Ā¹ in wheat grain with 60 g Se haā»Ā¹ . For Zn, soil-applied zinc sulphate was only found to be effective for increasing the Zn concentration in cabbage leaf and canola seed, with 35 and 61 mg kg ā»Ā¹, respectively, while foliar zinc sulphate application was effective in biofortifying winter wheat, increasing grain Zn from 20 to 30 mg kgā»Ā¹ . While for I, soil-applied potassium iodate was only effective in increasing I concentration in cabbage leaf, and biofortification of the other crops was not possible. The enhancements of Se, Zn, and I concentration resulting from either the single or combined application of microelement fertilizers were similar. Therefore, agronomic biofortification of edible parts of various food crops with Zn, Se, and I can be an effective way to increase micronutrient concentrations, and the effectiveness depends on crop species, fertilizer forms and application methods.H. Mao, J. Wang, Z. Wang, Y. Zan, G. Lyons, C. Zo

    LiSc(BH_4)_4 as a Hydrogen Storage Material: Multinuclear High-Resolution Solid-State NMR and First-Principles Density Functional Theory Studies

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    A lithium salt of anionic scandium tetraborohydride complex, LiSc(BH_4)_4, was studied both experimentally and theoretically as a potential hydrogen storage medium. Ball milling mixtures of LiBH_4 and ScCl_3 produced LiCl and a unique crystalline hydride, which has been unequivocally identified via multinuclear solid-state nuclear magnetic resonance (NMR) to be LiSc(BH_4)_4. Under the present reaction conditions, there was no evidence for the formation of binary Sc(BH_4)_3. These observations are in agreement with our first-principles calculations of the relative stabilities of these phases. A tetragonal structure in space group I (#82) is predicted to be the lowest energy state for LiSc(BH_4)_4, which does not correspond to structures obtained to date on the crystalline ternary borohydride phases made by ball milling. Perhaps reaction conditions are resulting in formation of other polymorphs, which should be investigated in future studies via neutron scattering on deuterides. Hydrogen desorption while heating these Liāˆ’Scāˆ’Bāˆ’H materials up to 400 Ā°C yielded only amorphous phases (besides the virtually unchanged LiCl) that were determined by NMR to be primarily ScB_2 and [B_(12)H_(12)]^(āˆ’2) anion containing (e.g., Li_2B_(12)H_(12)) along with residual LiBH_4. Reaction of a desorbed LiSc(BH_4)_4 + 4LiCl mixture (from 4LiBH_4/ScCl_3 sample) with hydrogen gas at 70 bar resulted only in an increase in the contents of Li_2B_(12)H_(12) and LiBH_4. Full reversibility to reform the LiSc(BH_4)_4 was not found. Overall, the Liāˆ’Scāˆ’Bāˆ’H system is not a favorable candidate for hydrogen storage applications

    Novel polymorphism of the bovine fat mass and obesity-associated (FTO) gene are related to backfat thickness and longissimus muscle area in five Chinese native cattle breeds

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    In this study, genetic variation of the fat mass and obesity-associated gene (FTO) was detected by PCRSSCP and DNA sequencing in 618 individuals from five Chinese indigenous cattle breeds, and their genetic effects on meat quality traits were evaluated. The results showed that a novel single nucleotide polymorphism C1071T was detected in exon 5 and the allelic frequencies for the C and T alleles of the five breeds were 0.666/0.334, 0.583/0.417, 0.631/0.369, 0.653/0.347 and 0.689/0.311, respectively. Animals with CT genotype had higher mean values for backfat thickness than those with CC or TT genotypes (P < 0.01). Individuals with CC or CT genotypes had higher longissimus muscle area than those with TT genotype (P < 0.05). The FTO gene may be a candidate gene for identifying differences in meat quality traits and therefore, could be applied to marker-assisted selection of native Chinese cattle breeds.Key words: Cattle, fat mass and obesity-associated (FTO) gene, single nucleotide polymorphism (SNP), meat quality traits

    An optimal rewiring strategy for cooperative multiagent social learning

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    Multiagent coordination is a key problem in cooperative multiagent systems (MASs). It has been widely studied in both fixed-agent repeated interaction setting and static social learning framework. However, two aspects of dynamics in real-world MASs are currently neglected. First, the network topologies can change during the course of interaction dynamically. Second, the interaction utilities can be different among each pair of agents and usually unknown before interaction. Both issues mentioned above increase the difficulty of coordination. In this paper, we consider the multiagent social learning in a dynamic environment in which agents can alter their connections and interact with randomly chosen neighbors with unknown utilities beforehand. We propose an optimal rewiring strategy to select most beneficial peers to maximize the accumulated payoffs in long-run interactions. We empirically demonstrate the effects of our approach in a variety of large-scale MASs

    Effect of sex on meat quality characteristics of Qinchuan cattle

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    A total of 18 Qinchuan cattle, six intact males (IM), six castrated males (CM) and six females (FM), were used to investigate the effect of sex on the physicochemical characteristics (PCC) and fatty acid (FA) composition of the Longissimus dorsi muscle (LDM). Obvious sex differences were found in the PCC of LDM: the IM group had higher shear value, pH, drip and cooking losses, and contents of ash and hydroxyproline (Hyp) than the CM and FM groups, as well as lower ether extract content and lightness. Both the IM and CM groups had lower water content and higher protein content than the FM group. Sex differences were also observed in contents of C14:0, C14:1, C18:1, saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and unsaturated fatty acids (UFA) between the IM and both the CM and FM groups but not between the CM and FM groups. The results indicated that sex is an importantsource of differences in meat quality of Qinchuan cattle because the castration and the meat characteristics of the CM group were more similar to the FM than the IM group

    Evaluation of temperature distribution for bone drilling considering aging factor

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    Bone drilling is a routine operation in surgeries, such as neurosurgery and orthopedics. However, the excessive drilling temperature may cause severe thermal damage to the bone tissue. Therefore, the drilling temperature determination of bone tissue can reduce the harm caused by thermal damage. A time-varying temperature field simulation model of bone drilling was set up by ABAQUS software in this paper, based on the Johnson-Cook model. Then it was validated with experiments by drilling cortical bone of fresh bovine shaft of the femur. The relative error between the experimental values and the theoretical values within 7.67% showed a good consistency. Furthermore, the aging factor is also considered to evaluate the temperature field of bone drilling. The results showed that the drilling temperature near the bone-drill area increased significantly. The drilling temperature of cortical bone decreases sharply with the radial distance and exhibits a hysteresis lag in the axial distribution. The aging factor mainly affects the peak of drilling temperature. The peak of drilling temperature tends to increase with age. The peak drilling temperature in the elderly (70y) was up to 6.8% higher than that in the young (20y), indicating that the elderly is more prone to excessive drilling temperature. Therefore, special attention should be paid to the temperature control of elderly bone tissue

    Solderability of Sn-0.7Cu/Si3N4 lead-free composite solder on Cu-substrate

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    AbstractReinforcing high performance ceramic particulates is an effective approach to improve solderability of lead-free Sn-0.7Cu solder. Various weight percentage compositions (0.5, 1.0, and 1.5) of Silicon Nitride (Si3N4) reinforced in Sn-0.7Cu solder were developed using powder metallurgy (PM) routes to investigate their solderability properties on copper (Cu) substrate. The solderability performances of the new composite solder will be determined and analyzed based on their contact angles on Cu substrate, including interface intermetallic compound (IMC) layer thickness and IMC phases formed for different Si3N4 ratios. Results also show an improvement in solderability of the Sn-0.7Cu/Si3N4 composite lead-free solder with optimum wettability achieved by 1.0wt.% Si3N4. The minimal average decrease in IMC layer thickness and the formation of the different shaped of scallops figuring the IMC layer were observed. X-ray diffraction (XRD) also revealed the decreasing peak intensity of Cu6Sn5 phases with Si3N4. Overall, the entire range of composition of Si3N4 into Sn-0.7Cu monolithic solder use in this study indicated an enhancement of solderability performances on Cu-substrates

    Graphene re-knits its holes

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    Nano-holes, etched under an electron beam at room temperature in singlelayer graphene sheets as a result of their interaction with metalimpurities, are shown to heal spontaneously by filling up with either non-hexagon, graphene-like, or perfect hexagon 2D structures. Scanning transmission electron microscopy was employed to capture the healing process and study atom-by-atom the re-grown structure. A combination of these nano-scale etching and re-knitting processes could lead to new graphene tailoring approaches.Comment: 11 pages, 4 figure

    Managing Change and Master Plans: Machu Picchu Between Conservation and Exploitation

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    Machu Picchu is among the world\u2019s most controversial heritage sites. It represents a case where raising money through ticket sales and other activities, rather than an opportunity to fund site preservation, in fact constitutes a major threat to the survival of the site through overexploitation. Unesco has been very critical in recent decades about the management of Machu Picchu. International pressure resulted in the establishment of two master plans, in 1998 and in 2005. In this paper we investigate in depth the contents and rhetoric of the two plans, comparing changes in the two different versions, and linking the change in planning attitude to actual changes taking place in the site. This is also an opportunity to open a discussion on the interdisciplinarity of master plans in heritage sites
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