6,248 research outputs found
Swarm-Oscillators
Nonlinear coupling between inter- and intra-element dynamics appears as a
collective behaviour of elements. The elements in this paper denote symptoms
such as a bacterium having an internal network of genes and proteins, a
reactive droplet, a neuron in networks, etc. In order to elucidate the
capability of such systems, a simple and reasonable model is derived. This
model exhibits the rich patterns of systems such as cell membrane, cell fusion,
cell growing, cell division, firework, branch, and clustered clusters
(self-organized hierarchical structure, modular network). This model is
extremely simple yet powerful; therefore, it is expected to impact several
disciplines.Comment: 9 pages, 4 figure
Optical study of MgTiO: Evidence for an orbital-Peierls state
Dimension reduction due to the orbital ordering has recently been proposed to
explain the exotic charge, magnetic and structural transitions in some
three-dimensional (3D) transitional metal oxides. We present optical
measurement on a spinel compound MgTiO which undergoes a sharp
metal-insulator transition at 240 K, and show that the spectral change across
the transition can be well understood from the proposed picture of 1D Peierls
transition driven by the ordering of and orbitals. We further
elaborate that the orbital-driven instability picture applies also very well to
the optical data of another spinel CuIrS reported earlier.Comment: 5 pages, 6 figures, to be published in Phys. Rev.
One-Loop Effect of Null-Like Cosmology's Holographic Dual Super-Yang-Mills
We calculate the 1-loop effect in super-Yang-Mills which preserves
1/4-supersymmetries and is holographically dual to the null-like cosmology with
a big-bang singularity. Though the bosonic and fermionic spectra do not agree
precisely, we do obtain vanishing 1-loop vacuum energy for generic warped
plane-wave type backgrounds with a big-bang singularity. Moreover, we find that
the cosmological "constant" contributed either by bosons or fermions is
time-dependent. The issues about the particle production of some background and
about the UV structure are also commented. We argue that the effective higher
derivative interactions are suppressed as long as the Fourier transform of the
time-dependent coupling is UV-finite. Our result holds for scalar
configurations that are BPS but with arbitrary time-dependence. This suggests
the existence of non-renormalization theorem for such a new class of
time-dependent theories. Altogether, it implies that such a super-Yang-Mills is
scale-invariant, and that its dual bulk quantum gravity might behave regularly
near the big bang.Comment: 20 pages, v2 add comments and references, v3 clarify BPS condition &
add new discussion on particle production and UV structure, v4&v5 minor
changes, final to JHE
CRISPR Knockout of the HuR Gene Causes a Xenograft Lethal Phenotype.
Pancreatic ductal adenocarcinoma (PDA) is the third leading cause of cancer-related deaths in the United States, whereas colorectal cancer is the third most common cancer. The RNA-binding protein HuR (ELAVL1) supports a pro-oncogenic network in gastrointestinal (GI) cancer cells through enhanced HuR expression. Using a publically available database, HuR expression levels were determined to be increased in primary PDA and colorectal cancer tumor cohorts as compared with normal pancreas and colon tissues, respectively. CRISPR/Cas9 technology was successfully used to delete the HuR gene in both PDA (MIA PaCa-2 and Hs 766T) and colorectal cancer (HCT116) cell lines. HuR deficiency has a mild phenotype
Impermeability effects in three-dimensional vesicles
We analyse the effects that the impermeability constraint induces on the
equilibrium shapes of a three-dimensional vesicle hosting a rigid inclusion. A
given alteration of the inclusion and/or vesicle parameters leads to shape
modifications of different orders of magnitude, when applied to permeable or
impermeable vesicles. Moreover, the enclosed-volume constraint wrecks the
uniqueness of stationary equilibrium shapes, and gives rise to pear-shaped or
stomatocyte-like vesicles.Comment: 16 pages, 7 figure
Inhibition of miR-146a-5p and miR-8114 in Insulin- Secreting Cells Contributes to the Protection of Melatonin against Stearic Acid-Induced Cellular Senescence by Targeting Mafa.
Chronic exposure to elevated levels of saturated fatty acids results in pancreatic β-cell senescence. However, targets and effective agents for preventing stearic acid-induced β-cell senescence are still lacking. Although melatonin administration can protect β-cells against lipotoxicity through anti-senescence processes, the precise underlying mechanisms still need to be explored. Therefore, we investigated the anti-senescence effect of melatonin on stearic acid-treated mouse β-cells and elucidated the possible role of microRNAs in this process.
β-Cell senescence was identified by measuring the expression of senescence-related genes and senescence-associated β-galactosidase staining. Gain- and loss-of-function approaches were used to investigate the involvement of microRNAs in stearic acid-evoked β-cell senescence and dysfunction. Bioinformatics analyses and luciferase reporter activity assays were applied to predict the direct targets of microRNAs.
Long-term exposure to a high concentration of stearic acid-induced senescence and upregulated miR-146a-5p and miR- 8114 expression in both mouse islets and β-TC6 cell lines. Melatonin effectively suppressed this process and reduced the levels of these two miRNAs. A remarkable reversibility of stearic acid-induced β-cell senescence and dysfunction was observed after silencing miR-146a-5p and miR-8114. Moreover, V-maf musculoaponeurotic fibrosarcoma oncogene homolog A (Mafa) was verified as a direct target of miR-146a-5p and miR-8114. Melatonin also significantly ameliorated senescence and dysfunction in miR-146a-5pand miR-8114-transfected β-cells.
These data demonstrate that melatonin protects against stearic acid-induced β-cell senescence by inhibiting miR-146a- 5p and miR-8114 and upregulating Mafa expression. This not only provides novel targets for preventing stearic acid-induced β-cell dysfunction, but also points to melatonin as a promising drug to combat type 2 diabetes progression
Diagnostic de la contamination des eaux par les éléments traces métalliques dans la zone aurifère de Komabangou – Tillabéri, Niger
A Komabangou, dans la région de Tillabéri au Niger, l’or est exploité, durant des décennies, de manière artisanale avec l’utilisation des méthodes inadéquates et des substances peu respectueuses de l’environnement comme le mercure et le cyanure. La présente étude a pour objectif de déterminer les teneurs en éléments traces métalliques (ETM) des eaux de Komabangou afin de prévoir les risques environnementaux et sanitaires liés à leur utilisation. Ainsi, des prélèvements d’eau ont été effectués sur 8 sites d’extraction d’or, 4 forages et 3 mares, et leurs concentrations en métaux tels que As, Cd, Cu, Hg, Ni, Pb et Zn ont été analysées par spectrométrie de masse avec plasma à couplage inductif (ICP-MS). Les résultats obtenus révèlent une contamination importante de ces eaux et soulignent une variabilité significative des concentrations des ETM en fonction du métal analysé et du type d’eau. Dans la plupart des eaux, les valeurs limites réglementaires notamment celles de l’OMS ont été dépassées, cela pourrait poser des problèmes de toxicité pour les plantes, les animaux et la population locale. Par conséquent, la mise en place d’un programme de surveillance et de traitement des eaux contaminées de la zone de Komabangou serait nécessaire pour réduire les risques de contamination humaine.Mots clés : ETM, eaux, risque, site aurifère, Komabangou, Niger
The Narrow-Line Regions of LINERs as Resolved with the Hubble Space Telescope
LINERs exist in the nuclei of a large fraction of luminous galaxies, but
their connection with the AGN phenomenon has remained elusive. We present
Hubble Space Telescope narrowband [O III]5007 and H-alpha+[N II] emission-line
images of the central regions of 14 galaxies with LINER nuclei. The compact, ~1
arcsec-scale, unresolved emission that dominates the line flux in ground-based
observations is mostly resolved by HST. The bulk of this emission comes from
regions with sizes of tens to hundreds of parsecs that are resolved into knots,
filaments, and diffuse gas whose morphology differs from galaxy to galaxy. Most
of the galaxies do not show clear linear structures or ionization cones
analogous to those often seen in Seyfert galaxies. An exception is NGC 1052,
the prototypical LINER, in which we find a 3 arcsec-long (~ 250 pc) biconical
structure that is oriented on the sky along the galaxy's radio jet axis. Seven
of the galaxies have been shown in previously published HST images to have a
bright compact ultraviolet nuclear source, while the other seven do not have a
central UV source. Our images find evidence of dust in the nuclear regions of
all 14 galaxies, with clear indications of nuclear obscuration in most of the
"UV-dark" cases. The data suggest that the line-emitting gas in most LINERs is
photoionized by a central source (which may be stellar, nonstellar, or a
combination thereof) but that this source is often hidden from direct view. We
find no obvious morphological differences between LINERs with detected weak
broad H-alpha wings in their spectra and those with only narrow lines.
Likewise, there is no clear morphological distinction between objects whose UV
spectra are dominated by hot stars (e.g., NGC 4569) and those that are AGN-like
(e.g., NGC 4579).Comment: Accepted for publication in the ApJ. 25 pages, 3 tables, 9 JPEG
Figure
Network and Seiberg Duality
We define and study a new class of 4d N=1 superconformal quiver gauge
theories associated with a planar bipartite network. While UV description is
not unique due to Seiberg duality, we can classify the IR fixed points of the
theory by a permutation, or equivalently a cell of the totally non-negative
Grassmannian. The story is similar to a bipartite network on the torus
classified by a Newton polygon. We then generalize the network to a general
bordered Riemann surface and define IR SCFT from the geometric data of a
Riemann surface. We also comment on IR R-charges and superconformal indices of
our theories.Comment: 28 pages, 28 figures; v2: minor correction
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