845 research outputs found

    Influence of Intermetallic Particles on the Corrosion Properties of Extruded ZK60 Mg Alloy Containing Cu

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    The microstructure and corrosion behavior of the extruded ZK60 Mg alloys with different Cu content were comparatively investigated. The ZK60 alloy had a microstructure consisting of ??-Mg grains with intermetallic MgZn2 and Zn2Zr3 particles. The addition of 1 wt % Cu resulted in the additional presence of CuMgZn particles. In a 0.6 M NaCl solution at 25 ??C, the corrosion rate of the alloy with the added Cu appeared to be about 16% faster than that of the alloy without the addition of Cu. The factors affecting the degraded corrosion resistance of the Cu-added ZK60 alloy are discussed

    Unified Hierarchical Relationship Between Thermodynamic Tradeoff Relations

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    Recent years have witnessed a surge of discoveries in the studies of thermodynamic inequalities: the thermodynamic uncertainty relation (TUR) and the entropic bound (EB) provide a lower bound on the entropy production (EP) in terms of nonequilibrium currents; the classical speed limit (CSL) expresses the lower bound on the EP using the geometry of probability distributions; the power-efficiency (PE) tradeoff dictates the maximum power achievable for a heat engine given the level of its thermal efficiency. In this study, we show that there exists a unified hierarchical structure encompassing all of these bounds, with the fundamental inequality given by a novel extension of the TUR (XTUR) that incorporates the most general range of current-like and state-dependent observables. By selecting more specific observables, the TUR and the EB follow from the XTUR, and the CSL and the PE tradeoff follow from the EB. Our derivations cover both Langevin and Markov jump systems, with the first proof of the EB for the Markov jump systems and a more generalized form of the CSL. We also present concrete examples of the EB for the Markov jump systems and the generalized CSL.Comment: 19 pages, 4 figure

    VCGIDB: A database and web resource for the genomic islands from Vibrio cholerae

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    Vibrio cholerae is the causative agent of cholera, which is a severe, life-threatening diarrheal disease. The current seventh pandemic has not been eradicated and the outbreak is still ongoing around the world. The evolution of the pandemic-causing strain has been greatly influenced by lateral gene transfer, and the mechanisms of acquisition of pathogenicity in V. cholerae are mainly involved with genomic islands (GIs). Thus, detecting GIs and their comprehensive information is necessary to understand the continuing resurgence and newly emerging pathogenic V. cholerae strains. In this study, 798 V. cholerae strains were tested using the GI-Scanner algorithm, which was developed to detect candidate GIs and identify them in a comparative genomics approach. The algorithm predicted 435 highly possible genomic islands, and we built a database, called Vibrio cholerae Genomic Island Database (VCGIDB). This database shows advanced results that were acquired from a large genome set using phylogeny-based predictions. Moreover, VCGIDB is a highly expendable database that does not require intensive computation, which enables us to update it with a greater number of genomes using a novel genomic island prediction method. The VCGIDB website allows the user to browse the data and presents the results in a visual manner.

    Arctic-North Pacific Coupled Impacts on the Late Autumn Cold in North America

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    The Pacific Decadal Oscillation (PDO) is known to bring an anomalously cold (warm) period to southeastern (northwestern) North America during the cold season of its positive phase through a Rossby wave linkage. This study provides evidence that the remote connection between the North Pacific and the downstream temperature over central North America is strengthened by the warm arctic conditions over the Chukchi and East Siberian Sea, especially in the late autumn season. The modulation effect of the Arctic manifests itself as an altered Rossby wave response to a transient vorticity forcing that results from an equatorward storm track shift, which is induced collaboratively by the PDO and the warm Arctic. This observational finding is supported by two independent modeling experiments: 1) an idealized coupled GCM experiment being nudged toward the warm arctic surface condition and 2) a simple stationary wave model (SWM) experiment forced by transient eddy forcing

    Novel Natural Polymer/Medicinal Plant Extract Electrospun Nanofiber for Cosmeceutical Application

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    Zein produced from maize is a hydrophobic protein, which holds great potential for a number of industrial applications, for example, food packaging, pharmaceutical, cosmetic, and biomedical industry. Sorghum, known as important cereal crop worldwide, is a good source of various phytochemicals such as tannins, phenolic acids, anthocyanins, phytosterols, and policosanols, and these phytochemicals have great impact on human health. Poria cocos, a well‐known traditional East‐Asian medicinal plant, is found around the roots of pine trees in Korea and China. As a rapid and efficient process, electrospinning has drawn huge interest among scientists to produce nanostructured polymer materials with excellent properties. In this work, we studied the influence of co‐solvent ratio and concentration of zein/medicinal plant extract on the morphologies of nanostructured zein/medicinal plant extract nanomaterials prepared by electrospinning technique from ethanol/water solution. The zein/medicinal extract nanofibers were characterized by field‐emission scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and differential scanning calorimetric technique. And we were to incorporate medicinal plant resources into the electro‐spun zein nanofibers by electrospinning technique to investigate the effect of medicinal extract on the morphologies, antibacterial, antioxidant, and other properties. Zein/medicinal plant extract might have a practical use as a new preservative for cosmeceutical applications

    How Does the SST Variability over the Western North Atlantic Ocean Control Arctic Warming over the Barents-Kara Seas?

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    Arctic warming over the BarentsKara Seas and its impacts on the mid-latitude circulations have been widely discussed. However, the specific mechanism that brings the warming still remains unclear. In this study, a possible cause of the regional Arctic warming over the BarentsKara Seas during early winter (OctoberDecember) is suggested. We found that warmer sea surface temperature anomalies over the western North Atlantic Ocean (WNAO) modulate the transient eddies overlying the oceanic frontal region. The altered transient eddy vorticity flux acts as a source for the Rossby wave straddling the western North Atlantic and the BarentsKara Seas (Scandinavian pattern), and induces a significant warm advection, increasing surface and lower-level temperature over the Eurasian sector of the Arctic Ocean. The importance of the sea surface temperature anomalies over the WNAO and subsequent transient eddy forcing over the WNAO was also supported by both specially designed simple model experiments and general circulation model experiments

    Soy food intake behavior by socio-demographic characteristics of Korean housewives

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    In this study, the soy food intake behaviors including perception and intake frequency of soybean foods by sociodemographic variables were analyzed in housewives. The perception of housewives for soy foods showed that soybean paste, soybean curd, and Dambuk were high in the descending order for nutritional quality and health promotion effect, and soybean paste received the highest score in taste and flavor. Soybean sprouts received the highest evaluation score in the economic aspect. In the aspect of safe food, soybean paste received the highest evaluation score, as mush as a traditional food. The analysis of perception by sociodemographic variables showed that soybean curd, Dambuk, and soybean sprouts had higher perceptions as education level increased, and soy milk had higher perceptions in subjects with younger age and with employment. In the intake frequency, more than 50% of the subjects had soybean curd, soybean sprouts, and soybean paste more than once a week. The analysis for correlation between the intake frequency of soy foods and the degree of perception showed that taste and flavor had high correlation with the intake frequency of soy foods except soybean sprouts. The intake frequency of soybean paste, Dambuk, and soy milk had positive correlations to familiarity and that of soy milk had positive correlations to nutrition and health perception, and those of soybeam paste, soybean sprouts, and soy milk had positive correlations to safe food perception. From the above results, housewives in Korea had very high perceptions to nutritional quality and health promotion effect of soy foods and the degree of perception and accompanied intake frequency had significant differences by age, education level, and economic level among sociodemographic variables

    Photodynamic Therapy Combined with CO2 Laser Vaporization on Disseminated Superficial Actinic Porokeratosis: A Report of 2 Cases on the Face

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    Disseminated superficial actinic porokeratosis (DSAP) is a skin condition that usually shows a poor response to different modalities of treatment. Herein we describe 2 patients with DSAP on the face, each treated with 3 to 4 sessions of photodynamic therapy combined with laser vaporization

    Foraging Behavior and Diet of Northward Migrating Bar-Tailed Godwits (Limosa laponica) and Great Knots (Calidris tenuirostris) at a Key Stopover Site

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    After the completion of the Saemangeum reclamation, the Geum Estuary has emerged as a key feeding and rooting site (staging site) for shorebirds in South Korea. However, there has yet to be any study conducted on the behavior and diet of shorebirds in this region. In this study, we first compared behavior and diet of two representative shorebird species with different morphologies, Bar-tailed Godwits (Limosa laponica) and Great Knots (Calidris tenuirostris) that co-occur in the tidal flat of Yubu Island near the Geum Estuary. During the April to May of 2016, using a camera equipped with a telescope, we recorded 36 individuals during low tide. Behavior was significantly different between the two shorebird species (Chi-square test, P = 0.037), although feeding success rate was similar between the two species (ANOVA, P > 0.05); the Bar-tailed Godwit showed more probings and less peckings than the Great Knot. In addition, Bar-tailed Godwits walked less (ANOVA, P < 0.001) and were less alert (ANOVA, P < 0.005) than Great Knots. On the other hand, diet composition was significantly different between them (Chi-square test, P = 0.010); Both species fed mainly upon Mollusca but the Great Knot fed on noticeably more Annelida (lugworms) than the Bar-tailed Godwit. Among Mollusca, both species consumed more gastropods than bivalves (ANOVA, P < 0.001).Based on these results, it is thought that Bar-tailed Godwits may save energy through less pecking together with less walking and less being alert, since it fed on less food than Great Knots. These results on behavior and diet will be helpful for conservation of the two species in the Geum Estuary tidal flats, a key stopover site of many shorebirds in the East Asian-Australasian Flyway (EAAF)

    Dual Effect of Chrysanthemum indicum

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    The risk of bone-related diseases increases due to the imbalance between bone resorption and bone formation by osteoclasts and osteoblasts, respectively. The goal in the development of antiosteoporotic treatments is an agent that will improve bone through simultaneous osteoblast stimulation and osteoclast inhibition without undesirable side effects. To achieve this goal, numerous studies have been performed to identify novel approaches using natural oriental herbs to treat bone metabolic diseases. In the present study, we investigated the effect of Chrysanthemum indicum extract (CIE) on the differentiation of osteoclastic and osteoblastic cells. CIE inhibited the formation of TRAP-positive mature osteoclasts and of filamentous-actin rings and disrupted the bone-resorbing activity of mature osteoclasts in a dose-dependent manner. CIE strongly inhibited Akt, GSK3β, and IκB phosphorylation in RANKL-stimulated bone marrow macrophages and did not show any effects on MAP kinases, including p38, ERK, and JNK. Interestingly, CIE also enhanced primary osteoblast differentiation via upregulation of the expression of alkaline phosphatase and the level of extracellular calcium concentrations during the early and terminal stages of differentiation, respectively. Our results revealed that CIE could have a potential therapeutic role in bone-related disorders through its dual effects on osteoclast and osteoblast differentiation
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