2,788 research outputs found

    Screening of external magnetic perturbation fields due to sheared plasma flow

    Get PDF
    Within the single fluid resistive magnetohydrodynamic model, systematic toroidal modelling efforts are devoted to investigate the plasma response induced screening of the applied external 3D magnetic field perturbations in the presence of sheared toroidal flow. One particular issue of interest is addressed, when the local flow speed approaches zero at the perturbation rational surface inside the plasma. Subtle screening physics, associated with the favourable averaged toroidal curvature effect (the GGJ effect (Glasser et al 1975 Phys. Fluids 7 875)), is found to play an essential role during slow flow near the rational surface by enhancing the screening at reduced flow. A strong cancellation effect between different terms of Ohm's law is discovered, leading to different screening physics in the GGJ regime, as compared to that of conventional screening of the typical resistive-inertial regime occurring at faster flow. These modelling results may be applicable to interpret certain mode locking experiments, as well as type-I edge localized mode suppression experiments, with resonant magnetic field perturbations being applied to tokamak plasmas at low input toroidal torque

    Application of GGBFS and Bentonite to Auto-Healing Cracks of Cement Paste

    Get PDF
    Cracks are caused by many factors. Shrinkage and external loading are the most common reason. It becomes a problem when the ingression of aggressive and harmful substance penetrates to the concrete gap. This problem reduces the durability of the structures. It is well known that self – healing of cracks significantly improves the durability of the concrete structure. This paper presents self-healing cracks of cement paste containing bentonite associated with ground granulated blast furnace slag. The self-healing properties were evaluated with four parameters: crack width on the surface, crack depth, tensile strength recovery, and flexural recovery. In combination with microscopic observation, a healing process over time is also performed. The results show that bentonite improves the healing properties, in terms of surface crack width and crack depth. On the other hand, GGBFS could also improve the healing process, in terms of crack depth, direst tensile recovery, and flexural stiffness recovery. Carbonation reaction is believed as the main mechanism, which contributes the self-healing process as well as the continuous hydration progress

    Therapeutic effect of Dongbai-Tonglin-Fang, a Chinese herbal formula, on urinary tract infection in rat model.

    Get PDF
    ETHNOPHARMACOLOGICAL RELEVANCE: Traditional Chinese Medicine (TCM) has many obvious advantages in the treatment of chronic conditions such as urinary tract infection (UTI). Dongbai-Tonglin-Fang (DBTL), a Chinese herbal formula, has been used for the treatment of UTI for more than 40 years with proven efficacy. However, its mechanism of action is still unknown. AIM OF THE STUDY: The purpose of this study is to evaluate the therapeutic efficacy of DBTL and its mechanism of action in a rat UTI model. MATERIALS AND METHODS: E. coli solution induced UTI rat model was used to evaluate the therapeutic effect of DBTL on UTI. Biochemical indicators related to UTI were measured. The kidney tissue was stained with hematoxylin-eosin (HE) to observe pathological changes whilst the ear swelling, feet swelling, hot plate and body torsion tests were used to estimate the anti-inflammatory and analgesic effects of DBTL. RESULTS: After treatment with different doses of DBTL (1, 2, 4 g/kg), a decrease in weight of the kidney in the UTI rat model was observed. The contents of white blood cell, nitrite, urinary albumin, ketone body, bilirubin and occult blood in the urine were also reduced whilst an increase in the pH of urine was observed. HE staining showed that the pathological changes in the kidney tissue were alleviated. At the same time, ear swelling assay showed that the weight and the degree of swelling of the ear of the mice in DBTL groups were decreased remarkably. DBTL also reduced the degree of feet swelling of the rats caused by the adjuvant. Furthermore, with the DBTL treatment, the latency period of foot licking induced by thermal stimulation was increased while the number of twists was lessened. CONCLUSION: These results show that DBTL has an excellent therapeutic effect on UTI rats accompanying with anti-inflammation and analgesia. The data presented here lays the foundations for further investigations in the treatment of UTI

    Imaging propagative exciton polaritons in atomically thin WSe2 waveguides

    Get PDF
    The exciton polariton (EP) is a half-light and half-matter quasiparticle that is promising for exploring both fundamental quantum phenomena as well as photonic applications. Van der Waals materials, such as transition-metal dichalcogenide (TMD), emerge as a promising nanophotonics platform due to its support of long propagative EPs even at room temperature. However, real-space studies have been limited to bulk crystal waveguides with a thickness no less than 60 nm. Here we report the nano-optical imaging of the transverse-electric EPs in WSe2 nanoflakes down to a few atomic layers, which can be turned on and off by tuning the polarization state of the excitation laser. Unlike previously studied transverse-magnetic modes that exist only in bulk TMD waveguides, we found that the transverse-electric EPs could reside in ultrathin WSe2 samples, owing to the alignment of the electric field with the in-plane dipole orientation of two-dimensional excitons. Furthermore, we show that the EP wavelength and propagation length can be largely controlled by varying laser energy and sample thickness. These findings open opportunities to realize near-infrared polaritonic devices and circuits truly at the atomically thin limit

    Galactic interstellar sulfur isotopes: A radial 32^{32}S//34^{34}S gradient?

    Full text link
    We present observations of 12^{12}C32^{32}S, 12^{12}C34^{34}S, 13^{13}C32^{32}S and 12^{12}C33^{33}S J=2-1 lines toward a large sample of massive star forming regions by using the Arizona Radio Observatory 12-m telescope and the IRAM\,30-m. Taking new measurements of the carbon 12^{12}C/13^{13}C ratio, the 32^{32}S//34^{34}S isotope ratio was determined from the integrated 13^{13}C32^{32}S/12^{12}C34^{34}S line intensity ratios for our sample. Our analysis shows a 32^{32}S//34^{34}S gradient from the inner Galaxy out to a galactocentric distance of 12\,kpc. An unweighted least-squares fit to our data yields 32^{32}S//34^{34}S = (1.56 ±\pm 0.17)DGC\rm D_{\rm GC} + (6.75 ±\pm 1.22) with a correlation coefficient of 0.77. Errors represent 1σ\sigma standard deviations. Testing this result by (a) excluding the Galactic center region, (b) excluding all sources with C34^{34}S opacities >> 0.25, (c) combining our data and old data from previous study, and (d) using different sets of carbon isotope ratios leads to the conclusion that the observed 32^{32}S//34^{34}S gradient is not an artefact but persists irrespective of the choice of the sample and carbon isotope data. A gradient with rising 32^{32}S//34^{34}S values as a function of galactocentric radius implies that the solar system ratio should be larger than that of the local interstellar medium. With the new carbon isotope ratios we obtain indeed a local 32^{32}S//34^{34}S isotope ratio about 10%\% below the solar system one, as expected in case of decreasing 32^{32}S//34^{34}S ratios with time and increased amounts of stellar processing. However, taking older carbon isotope ratios based on a lesser amount of data, such a decrease is not seen. No systematic variation of 34^{34}S//33^{33}S ratios along galactocentric distance was found.Comment: 28 pages, 11 figures, 5 tables. Accepted for publication in Ap

    Efectos de las técnicas de procesamiento sobre la estabilidad oxidativa del aceite de semilla de Prunus pedunculatus

    Get PDF
    This paper investigated the effects of Prunus pedunculatus (P. pedunculatus) seed pre-treatment, including microwaving (M), roasting (R), steaming (S) and roasting plus steaming (RS) on crude oil quality in terms of yield, color change, fatty acid composition, and oxidative stability. The results showed an increase in monounsaturated fatty acid content and oxidative stability of the oils obtained from different processing treatments compared to the oil obtained from raw seeds (RW) without processing. The oils, obtained from pretreated seeds, had higher conjugated diene (CD) and 2-thiobarbituric acid (2-TBA) values, compared to that obtained from RW when stored in a Schaal oven at 65 °C for 168 h. However, polyphenol and tocopherol contents decreased in all oil samples, processed or unprocessed. The effect of pre-treating the seeds was more prominent in the oil sample obtained through the RS technique, and showed higher oxidative stability than the other processed oils and the oil from RW.Se investigó los efectos del pretratamiento de las semillas de Prunus pedunculatus, incluyendo microondas (M), tostado (R), cocción al vapor (S) y torrefacción más vapor (RS), sobre la calidad del aceite crudo, el rendimiento, cambio de color, composición en ácidos grasos y estabilidad oxidativa. Los resultados mostraron un aumento en el contenido de ácidos grasos monoinsaturados y en la estabilidad oxidativa de los aceites obtenidos con diferentes tratamientos de procesamiento en comparación con el aceite obtenido a partir de semillas crudas (RW) sin procesamiento. Los aceites obtenidos a partir de semillas pretratadas presentaron mayores valores de dienos conjugados (CD) y de ácido 2-tiobarbitúrico (2-TBA), comparado con el obtenido de RW cuando se almacenaron en horno a 65 °C durante 168 h. Sin embargo, el contenido de polifenoles y tocoferoles disminuyó en todas las muestras de aceites, procesadas o no procesadas. El efecto del pretratamiento de las semillas fue más destacado en la muestra de aceite obtenida mediante la técnica RS, mostrando mayor estabilidad oxidativa que los otros aceites procesados y que el aceite de RW

    [Colored solutions of Yang-Baxter equation from representations of U_{q}gl(2)]

    Full text link
    We study the Hopf algebra structure and the highest weight representation of a multiparameter version of Uqgl(2)U_{q}gl(2). The commutation relations as well as other Hopf algebra maps are explicitly given. We show that the multiparameter universal R{\cal R} matrix can be constructed directly as a quantum double intertwiner, without using Reshetikhin's transformation. An interesting feature automatically appears in the representation theory: it can be divided into two types, one for generic qq, the other for qq being a root of unity. When applying the representation theory to the multiparameter universal R{\cal R} matrix, the so called standard and nonstandard colored solutions R(μ,ν;μ,ν)R(\mu,\nu; {\mu}', {\nu}') of the Yang-Baxter equation is obtained.Comment: [14]pages, latex, no figure

    Time series canopy phenotyping enables the identification of genetic variants controlling dynamic phenotypes in soybean

    Get PDF
    Advances in plant phenotyping technologies are dramatically reducing the marginal costs of collecting multiple phenotypic measurements across several time points. Yet, most current approaches and best statistical practices implemented to link genetic and phenotypic variation in plants have been developed in an era of single-time-point data. Here, we used time-series phenotypic data collected with an unmanned aircraft system for a large panel of soybean (Glycine max (L.) Merr.) varieties to identify previously uncharacterized loci. Specifically, we focused on the dissection of canopy coverage (CC) variation from this rich data set. We also inferred the speed of canopy closure, an additional dimension of CC, from the time-series data, as it may represent an important trait for weed control. Genome-wide association studies (GWASs) identified 35 loci exhibiting dynamic associations with CC across developmental stages. The time-series data enabled the identification of 10 known flowering time and plant height quantitative trait loci (QTLs) detected in previous studies of adult plants and the identification of novel QTLs influencing CC. These novel QTLs were disproportionately likely to act earlier in development, which may explain why they were missed in previous single-time-point studies. Moreover, this time-series data set contributed to the high accuracy of the GWASs, which we evaluated by permutation tests, as evidenced by the repeated identification of loci across multiple time points. Two novel loci showed evidence of adaptive selection during domestication, with different genotypes/haplotypes favored in different geographic regions. In summary, the time-series data, with soybean CC as an example, improved the accuracy and statistical power to dissect the genetic basis of traits and offered a promising opportunity for crop breeding with quantitative growth curves
    corecore