4,870 research outputs found

    Effects of a Chinese Medicinal Plant Radix Astragali on the Ovariectomized Female Rats

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    Perimenopausal syndrome occurs during the transition to menopause. Complementary and alternative medicine, especially Chinese medicinal plants, has manifested significant effects in alleviating perimenopausal symptoms. However, little research has been focused on the effects of Chinese medicinal plant on the immune function of the perimenopausal women. The present study aimed to explore the effects of Radix Astragali (RA) on the sex hormone levels and the interleukins of the ovariectomized female rats. 24 female Sprague-Dawley (SD) rats were randomly divided into model control group (MOD group), sham-operation group (SHAM group), RA group and estrogen group (EST group). After all the treatment ended, the serum levels of estradiol (E2), follicle stimulating hormone (FSH), luteinizing hormone (LH), interleukin-2 (IL-2), and interleukin-8 (IL-8) were measured using enzyme-linked immune-sorbent assay (ELISA) and the uterus was removed and weighed after blood exsanguinations immediately. In the MOD group, the serum levels of E2 were significantly lower, and the serum levels of FSH and LH were markedly higher than those of the RA group, EST group and SHAM group (P<0.05). In the RA group, the serum levels of E2 were significantly lower, and the serum levels of FSH were markedly higher than those of the SHAM group and EST group, respectively. In the MOD group, the serum levels of IL-2 and IL-8 were significantly lower than those of the RA group, EST group and SHAM group (P<0.05), and no marked differences existed among RA group, EST group and SHAM group in the serum levels of IL-2 and IL-8 (P>0.05). The uterine weight of the rats in the RA group, EST group and SHAM group were significantly higher than those of the rats in MOD group (P<0.05). There were no marked differences among the rats from RA group, EST group and SHAM group on the uterine weight (P>0.05). It is concluded that RA can significantly improve the immune functions of the ovariectomized female rats, although it cannot change the sex hormones levels as significantly as estrogen

    Suppressing Impacts of the Amazonian Deforestation by the Global Circulation Change

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    Analyzing the Global Historical Climatology Network, outgoing longwave radiation, and NCEP–NCAR reanalysis data over the Amazon Basin, the authors find a clear interdecadal increasing trend over the past four decades in both rainfall and intensity of the hydrological cycle. These interdecadal variations are a result of the interdecadal change of the global divergent circulation. On the contrary, the impact of the Amazon deforestation as evaluated by all numerical studies has found a reduction of rainfall and evaporation, and an increase of temperature in the Amazon Basin extending its dry season. Evidently, the interdecadal trend of the basin\u27s hydrological cycle revealed from observations functions in a course opposite to the deforestation scenario. Results of this study suggest that future studies analyzing the impact of the basin–scale deforestation on the regional hydrological cycle and climate should be reassessed with multidecade numerical simulations including both schemes handling the land–surface processes and the mechanism generating proper interdecadal variation of the global divergent circulation

    GNSS Scintillations in the Cusp, and the Role of Precipitating Particle Energy Fluxes

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    Using a large data set of ground-based GNSS scintillation observations coupled with in situ particle detector data, we perform a statistical analysis of both the input energy flux from precipitating particles, and the observed occurrence of density irregularities in the northern hemisphere cusp. By examining trends in the two data sets relating to geomagnetic activity, we conclude that observations of irregularities in the cusp grows increasingly likely during storm-time, whereas the precipitating particle energy flux does not. We thus find a weak or nonexistent statistical link between geomagnetic activity and precipitating particle energy flux in the cusp. This is a result of a previously documented tendency for the cusp energy flux to maximize during northward IMF, when density irregularities tend not to be widespread, as we demonstrate. At any rate, even though ionization and subsequent density gradients directly caused by soft electron precipitation in the cusp are not to be ignored for the trigger of irregularities, our results point to the need to scrutinize additional physical processes for the creation of irregularities causing scintillations in and around the cusp. While numerous phenomena known to cause density irregularities have been identified and described, there is a need for a systematic evaluation of the conditions under which the various destabilizing mechanisms become important and how they sculpt the observed ionospheric “irregularity landscape.” As such, we call for a quantitative assessment of the role of particle precipitation in the cusp, given that other factors contribute to the production of irregularities in a major way

    Registration of ‘Matterhorn’ Hard White Waxy Winter Wheat

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    ‘Matterhorn’ (Reg. No. CV-1151, PI 687896) hard white winter waxy wheat (Triticum aestivum L.) was developed cooperatively by the USDA-ARS and the Nebraska Agricultural Experiment Station and released in 2018. Matterhorn, a sibling of the hard red waxy cultivar Mattern, has white grain color and waxy (amylose-free) endosperm starch. It was released primarily for its unique end-use quality attributes and for grain yield competitiveness with currently grown Nebraskaadapted cultivars. The waxy starch is conditioned by the presence of three naturally occurring mutations that eliminate production of the enzyme granule-bound starch synthase. Granule-bound starch synthase synthesizes amylose in typical wheats and other cereal crops. Matterhorn (tested as NX04Y2107W) was selected from the heterogeneous red/ white-seeded experimental line NX04Y2107 derived from the cross NW98S061/99Y1442

    Steepening Plasma Density Spectra in the Ionosphere: The Crucial Role Played by a Strong E-Region

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    Based on the Swarm 16 Hz Advanced Plasma Density data set, and using the Swarm A satellite, we apply automatic detection of spectral breaks in seven million sampled plasma density power spectra in the high-latitude F-region ionosphere. This way, we survey the presence of plasma irregularity dissipation due to an enhanced E-region conductance, caused both by solar photoionization and particle precipitation. We introduce a new quantity named the steepening slope index (SSI) which we use to estimate the occurrence rate of break-points in sampled plasma densities. We provide an interpretation of SSI in the context of solar photoionization-induced conductance enhancements of the E-region. We present a comprehensive climatology of the SSI occurrence rate, along with statistics documenting characteristic high-latitude plasma density spectra. In the absence of steepening, the typical spectral index is 2.1. When density spectra steepen, the index is typically 1.6 at large scales, and 2.7 at small scales. We discuss the impact of high-energy deeply penetrating electron precipitation in the diffuse aurora, and precipitating electrons in the aurora at large. Here, a key finding is that near the cusp, where the F-region conductance is enhanced, spectra tend not to steepen. We find that both the diffuse and discrete aurora are modulating F-region plasma irregularity dissipation through an enhancement of E-region conductance, highlighting the role played by factors other than solar zenith angle in high-latitude plasma dynamics. The influence of E-region conductance on spectral shapes indicates the need for a new discussion of how particle precipitation can structure the local winter high-latitude F-region ionosphere

    Spin chirality on a two-dimensional frustrated lattice

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    The collective behavior of interacting magnetic moments can be strongly influenced by the topology of the underlying lattice. In geometrically frustrated spin systems, interesting chiral correlations may develop that are related to the spin arrangement on triangular plaquettes. We report a study of the spin chirality on a two-dimensional geometrically frustrated lattice. Our new chemical synthesis methods allow us to produce large single crystal samples of KFe3(OH)6(SO4)2, an ideal Kagome lattice antiferromagnet. Combined thermodynamic and neutron scattering measurements reveal that the phase transition to the ordered ground-state is unusual. At low temperatures, application of a magnetic field induces a transition between states with different non-trivial spin-textures.Comment: 7 pages, 4 figure
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