30,766 research outputs found
Molecular mechanisms underlying anti-tumor promoting activities of heat-processed Panax ginseng C.A. Meyer.
Recently, there have been considerable efforts to search for naturally occurring substances that can inhibit, reverse, or retard the multi-stage carcinogenesis. A wide array of phenolic substances derived from edible and medicinal plants have been reported to possess anticarcinogenic and antimutagenic activities and in many cases, the chemopreventive activities of phytochemicals are associated with their anti-inflammatory and/or antioxidative properties. Panax ginseng C.A. Meyer cultivated in Korea has been widely used in traditional herbal medicine for the treatment of various diseases. Certain fractions or purified ingredients of ginseng have been shown to exert anticarcinogenic and antimutagenic activities. Our previous studies have revealed that the methanol extract of heat-processed Panax ginseng C.A. Meyer attenuates the lipid peroxidation in rat brain homogenates and is also capable of scavenging superoxide generated by xanthine- xanthine oxidase or by 12-O-tetradecanoylphorbol-13-acetate (TPA) in differentiated human promyelocytic leukemia (HL-60) cells. Topical application of the same extract onto shaven backs of female ICR mice also suppressed TPA-induced skin tumor promotion. Likewise, topical application of ginsenoside Rg3, one of the constituents of heat-treated ginseng, significantly inhibited TPA-induced mouse epidermal ornithine decarboxylase activity and skin tumor promotion. Expression of cyclooxygenase-2 (COX-2) in TPA-stimulated mouse skin was markedly suppressed by Rg3 pretreatment. In addition, Rg3 inhibited TPA-stimulated activation of NF-kappaB and extracellular-regulated protein kinase (ERK), one of the mitogen-activated protein (MAP) kinase in mouse skin and also in cultured human breast epithelial cells (MCF-10A)
Understanding Usage Patterns for Mobile Phone Excessive Dependence
The advancement of mobile technology has transformed a phone from a simple communication tool to a powerful device for entertainment, socialization and work. The proliferation of mobile apps further changed people’s way of living and working. However, more and more users experience excessive mobile phone dependence. The traditional method to identify dependence uses survey instruments and interview. However, this approach is labour intensive and hard to scale. To address the issue, this research-in-progress paper aims to identity users’ phone usage pattern and propose an unobtrusive way of diagnosing users’ mobile phone dependence. We have developed an app to track users’ phone usage and preliminary analysis was performed based on the data collected over more than 20 days. Users showed different usage patterns over weekends and weekdays, and social app usage is a more significant indicator for mobile phone excessive dependence than general phone usage. Planned future analysis and potential contributions are discussed
Visualizing the emergence of the pseudogap state and the evolution to superconductivity in a lightly hole-doped Mott insulator
Superconductivity emerges from the cuprate antiferromagnetic Mott state with
hole doping. The resulting electronic structure is not understood, although
changes in the state of oxygen atoms appear paramount. Hole doping first
destroys the Mott state yielding a weak insulator where electrons localize only
at low temperatures without a full energy gap. At higher doping, the
'pseudogap', a weakly conducting state with an anisotropic energy gap and
intra-unit-cell breaking of 90\degree-rotational (C4v) symmetry appears.
However, a direct visualization of the emergence of these phenomena with
increasing hole density has never been achieved. Here we report atomic-scale
imaging of electronic structure evolution from the weak-insulator through the
emergence of the pseudogap to the superconducting state in Ca2-xNaxCuO2Cl2. The
spectral signature of the pseudogap emerges at lowest doping from a weakly
insulating but C4v-symmetric matrix exhibiting a distinct spectral shape. At
slightly higher hole-density, nanoscale regions exhibiting pseudogap spectra
and 180\degree-rotational (C2v) symmetry form unidirectional clusters within
the C4v-symmetric matrix. Thus, hole-doping proceeds by the appearance of
nanoscale clusters of localized holes within which the broken-symmetry
pseudogap state is stabilized. A fundamentally two-component electronic
structure11 then exists in Ca2-xNaxCuO2Cl2 until the C2v-symmetric clusters
touch at higher doping, and the long-range superconductivity appears.Comment: See the Nature Physics website for the published version available at
http://dx.doi.org/10.1038/Nphys232
A Prediction of the B*_c mass in full lattice QCD
By using the Highly Improved Staggered Quark formalism to handle charm,
strange and light valence quarks in full lattice QCD, and NRQCD to handle
bottom valence quarks we are able to determine accurately ratios of the B meson
vector-pseudoscalar mass splittings, in particular,
(m(B*_c)-m(B_c))/(m(B*_s)-m(B_s)). We find this ratio to be 1.15(15), showing
the `light' quark mass dependence of this splitting to be very small. Hence we
predict m(B_c*) = 6.330(7)(2)(6) GeV where the first two errors are from the
lattice calculation and the third from existing experiment. This is the most
accurate prediction of a gold-plated hadron mass from lattice QCD to date.Comment: 4 pages, 2 figure
Large-scale Laboratory Observations of Turbulence and Shear Stresses in the Surf Zone
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive
Above-Room-Temperature Ferromagnetism in GaSb/Mn Digital Alloys
Digital alloys of GaSb/Mn have been fabricated by molecular beam epitaxy.
Transmission electron micrographs showed good crystal quality with individual
Mn-containing layers well resolved; no evidence of 3D MnSb precipitates was
seen in as-grown samples. All samples studied exhibited ferromagnetism with
temperature dependent hysteresis loops in the magnetization accompanied by
metallic p-type conductivity with a strong anomalous Hall effect (AHE) up to
400 K (limited by the experimental setup). The anomalous Hall effect shows
hysteresis loops at low temperatures and above room temperature very similar to
those seen in the magnetization. The strong AHE with hysteresis indicates that
the holes interact with the Mn spins above room temperature. All samples are
metallic, which is important for spintronics applications.
* To whom correspondence should be addressed. E-mail: [email protected]
Dynamics of a deformable self-propelled particle under external forcing
We investigate dynamics of a self-propelled deformable particle under
external field in two dimensions based on the model equations for the center of
mass and a tensor variable characterizing deformations. We consider two kinds
of external force. One is a gravitational-like force which enters additively in
the time-evolution equation for the center of mass. The other is an
electric-like force supposing that a dipole moment is induced in the particle.
This force is added to the equation for the deformation tensor. It is shown
that a rich variety of dynamics appears by changing the strength of the forces
and the migration velocity of self-propelled particle
Moho topography, ranges and folds of Tibet by analysis of global gravity models and GOCE data
The determination of the crustal structure is essential in geophysics, as it gives insight into the
geohistory, tectonic environment, geohazard mitigation, etc. Here we present the latest advance
on three-dimensional modeling representing the Tibetan Mohorovi\u10di\u107 discontinuity (topography and
ranges) and its deformation (fold), revealed by analyzing gravity data from GOCE mission. Our study
shows noticeable advances in estimated Tibetan Moho model which is superior to the results using
the earlier gravity models prior to GOCE. The higher quality gravity field of GOCE is reflected in the
Moho solution: we find that the Moho is deeper than 65 km, which is twice the normal continental
crust beneath most of the Qinghai-Tibetan plateau, while the deepest Moho, up to 82 km, is located
in western Tibet. The amplitude of the Moho fold is estimated to be ranging from 129 km to 9 km
with a standard deviation of ~2 km. The improved GOCE gravity derived Moho signals reveal a clear
directionality of the Moho ranges and Moho fold structure, orthogonal to deformation rates observed
by GPS. This geophysical feature, clearly more evident than the ones estimated using earlier gravity
models, reveals that it is the result of the large compressional tectonic process
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