3,473 research outputs found
Substituent position-induced color tunability in polymer light-emitting diodes
We report substituent position-induced color tunability in polymer light-emitting diodes fabricated with poly[2-{2- or 3- or 4-[(3,7-dimethyloctyl)oxy] phenyoxy}-1,4-phenylenevinylene] (DMOPPPV). When the position of the substituent in DMOP-PPV moves to the ortho, meta, and para sites, the corresponding photo- and electroluminescence spectra shift their peaks to a longer wavelength of about 540, 560, and 585 nm, respectively. We ascribe this to the different degree of steric effect in the backbone for each substituent position. As the substituent position is closer to the main chain, the planarity of the backbone is less conserved, thereby reducing the effective conjugated length of the main chain and broadening the pi-pi(*) energy gapopen6
Collider and Dark Matter Searches in Models with Mixed Modulus-Anomaly Mediated SUSY Breaking
We investigate the phenomenology of supersymmetric models where moduli fields
and the Weyl anomaly make comparable contributions to SUSY breaking effects in
the observable sector of fields. This mixed modulus-anomaly mediated
supersymmetry breaking (MM-AMSB) scenario is inspired by models of string
compactification with fluxes, which have been shown to yield a de Sitter vacuum
(as in the recent construction by Kachru {\it et al}). The phenomenology
depends on the so-called modular weights which, in turn, depend on the location
of various fields in the extra dimensions. We find that the model with zero
modular weights gives mass spectra characterized by very light top squarks
and/or tau sleptons, or where M_1\sim -M_2 so that the bino and wino are
approximately degenerate. The top squark mass can be in the range required by
successful electroweak baryogenesis. The measured relic density of cold dark
matter can be obtained via top squark co-annihilation at low \tan\beta, tau
slepton co-annihilation at large \tan\beta or via bino-wino coannihilation.
Then, we typically find low rates for direct and indirect detection of
neutralino dark matter. However, essentially all the WMAP-allowed parameter
space can be probed by experiments at the CERN LHC, while significant portions
may also be explored at an e^+e^- collider with \sqrt{s}=0.5--1 TeV. We also
investigate a case with non-zero modular weights. In this case,
co-annihilation, A-funnel annihilation and bulk annihilation of neutralinos are
all allowed. Results for future colliders are qualitatively similar, but
prospects for indirect dark matter searches via gamma rays and anti-particles
are somewhat better.Comment: 38 pages including 22 EPS figures; latest version posted to conform
with published versio
Holography For a De Sitter-Esque Geometry
Warped dS arises as a solution to topologically massive gravity (TMG)
with positive cosmological constant and Chern-Simons coefficient
in the region . It is given by a real line fibration
over two-dimensional de Sitter space and is equivalent to the rotating Nariai
geometry at fixed polar angle. We study the thermodynamic and asymptotic
structure of a family of geometries with warped dS asymptotics.
Interestingly, these solutions have both a cosmological horizon and an internal
one, and their entropy is unbounded from above unlike black holes in regular de
Sitter space. The asymptotic symmetry group resides at future infinity and is
given by a semi-direct product of a Virasoro algebra and a current algebra. The
right moving central charge vanishes when . We discuss the
possible holographic interpretation of these de Sitter-esque spacetimes.Comment: 22 pages, 1 figure; v2: typos corrected, to match with published
versio
Collider and Dark Matter Phenomenology of Models with Mirage Unification
We examine supersymmetric models with mixed modulus-anomaly mediated SUSY
breaking (MM-AMSB) soft terms which get comparable contributions to SUSY
breaking from moduli-mediation and anomaly-mediation. The apparent (mirage)
unification of soft SUSY breaking terms at Q=mu_mir not associated with any
physical threshold is the hallmark of this scenario. The MM-AMSB structure of
soft terms arises in models of string compactification with fluxes, where the
addition of an anti-brane leads to an uplifting potential and a de Sitter
universe, as first constructed by Kachru {\it et al.}. The phenomenology mainly
depends on the relative strength of moduli- and anomaly-mediated SUSY breaking
contributions, and on the Higgs and matter field modular weights, which are
determined by the location of these fields in the extra dimensions. We
delineate the allowed parameter space for a low and high value of tan(beta),
for a wide range of modular weight choices. We calculate the neutralino relic
density and display the WMAP-allowed regions. We show the reach of the CERN LHC
and of the International Linear Collider. We discuss aspects of MM-AMSB models
for Tevatron, LHC and ILC searches, muon g-2 and b->s \gamma branching
fraction. We also calculate direct and indirect dark matter detection rates,
and show that almost all WMAP-allowed models should be accessible to a
ton-scale noble gas detector. Finally, we comment on the potential of colliders
to measure the mirage unification scale and modular weights in the difficult
case where mu_mir>>M_GUT.Comment: 34 pages plus 42 EPS figures; version with high resolution figures is
at http://www.hep.fsu.edu/~bae
Enhancement of Wound Healing by Conditioned Medium of Adipose-Derived Stromal Cell with Photobiomodulation in Skin Wound
Background and Objectives: The objective of this study was to investigate whether conditioned medium from photobiomodulation (PBM) irradiated adipose-derived stromal cell (ASC) spheroids prior to implanting could stimulate angiogenesis and tissue regeneration to improve functional recovery of skin tissue in an animal skin wound model. Methods and Results: ASC were split and seeded on chitosan-coated 24 well plate at a density of 7.5×104 cells/cm2, and allowed to adhere at 37℃. Within 3 days of culture, ASC formed spheroids by PBM irradiation. Conditioned medium (CM) fractions were collected from the PBM-ASC to yield nor adipose-derived stromal cell spheroid (spheroid) and PBM-spheroid, respectively, centrifuged at 13,000 g at 4℃ for 10 min, and stored prior to use for ELISA, protein assay, or in vivo wound-healing assays. Phosphate-buffered saline, cultured CM from ASCs, PBM irradiation prior to implanting conditioned medium from ASC, cultured CM from ASC spheroid, and PBM–spheroid-CM (PSC) were transplanted into a wound bed in athymic mice to evaluate therapeutic effects of PSC in vivo. PSC enhanced wound closure in a skin injury model compared to PBS, CM, PBM–CM, and spheroid-CM. The density of vascular formations increased as a result of angiogenic factors released by the wound bed and enhanced tissue regeneration at the lesion site. Conclusions: These results indicate that implant of PSC can significantly improve functional recovery compared to PBS, CM, PBM–CM, or spheroid-CM treatment. Implant of PSC may be an effective form of paracrine mediated therapy for treating a wound bed
Anesthesia of Epinephelus marginatus with essential oil of Aloysia polystachya: an approach on blood parameters
This study investigated the anesthetic potential of the essential oil (EO) of Aloysia polystachya in juveniles of dusky grouper (Epinephelus marginatus). Fish were exposed to different concentrations of EO of A. polystachya to evaluate time of induction and recovery from anesthesia. In the second experiment, fish were divided into four groups: control, ethanol and 50 or 300 mu L L-1 EO of A. polystachya, and each group was submitted to induction for 3.5 min and recovery for 5 or 10 min. The blood gases and glucose levels showed alterations as a function of the recovery times, but Na+ and K+ levels did not show any alteration. In conclusion, the EO from leaves of A. polystachya is an effective anesthetic for dusky grouper, because anesthesia was reached within the recommended time at EO concentrations of 300 and 400 mu L L-1. However, most evaluated blood parameters showed compensatory responses due to EO exposure.Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul/Programa de Apoio a Nucleos de Excelencia (FAPERGS/PRONEX) [10/0016-8]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [470964/2009-0]; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior, Brazil (CAPES)info:eu-repo/semantics/publishedVersio
Galactic and Extragalactic Samples of Supernova Remnants: How They Are Identified and What They Tell Us
Supernova remnants (SNRs) arise from the interaction between the ejecta of a
supernova (SN) explosion and the surrounding circumstellar and interstellar
medium. Some SNRs, mostly nearby SNRs, can be studied in great detail. However,
to understand SNRs as a whole, large samples of SNRs must be assembled and
studied. Here, we describe the radio, optical, and X-ray techniques which have
been used to identify and characterize almost 300 Galactic SNRs and more than
1200 extragalactic SNRs. We then discuss which types of SNRs are being found
and which are not. We examine the degree to which the luminosity functions,
surface-brightness distributions and multi-wavelength comparisons of the
samples can be interpreted to determine the class properties of SNRs and
describe efforts to establish the type of SN explosion associated with a SNR.
We conclude that in order to better understand the class properties of SNRs, it
is more important to study (and obtain additional data on) the SNRs in galaxies
with extant samples at multiple wavelength bands than it is to obtain samples
of SNRs in other galaxiesComment: Final 2016 draft of a chapter in "Handbook of Supernovae" edited by
Athem W. Alsabti and Paul Murdin. Final version available at
https://doi.org/10.1007/978-3-319-20794-0_90-
Cysteine oxidation targets peroxiredoxins 1 and 2 for exosomal release through a novel mechanism of redox-dependent secretion
Non-classical protein secretion is of major importance as a number of cytokines and inflammatory mediators are secreted via this route. Current evidence indicates that there are several mechanistically distinct methods of non-classical secretion. We have recently shown that peroxiredoxin (Prdx) 1 and Prdx2 are released by various cells upon exposure to inflammatory stimuli such as LPS or TNF-α. The released Prdx then acts to induce production of inflammatory cytokines. However, Prdx1 and 2 do not have signal peptides and therefore must be secreted by alternative mechanisms as has been postulated for the inflammatory mediators IL-1β and HMGB1. We show here that circulating Prdx1 and 2 are present exclusively as disulphide-linked homodimers. Inflammatory stimuli also induce in vitro release of Prdx1 and 2 as disulfide-linked homodimers. Mutation of cysteines Cys51 or Cys172 (but not Cys70) in Prdx2, and Cys52 or Cys173 (but not Cys71 or Cys83) in Prdx1 prevented dimer formation and this was associated with inhibition of their TNF-α-induced release. Thus, the presence and oxidation of key cysteine residues in these proteins are a prerequisite for their secretion in response to TNF-α and this release can be induced with an oxidant. In contrast, the secretion of the nuclear-associated danger signal HMGB1 is independent of cysteine oxidation, as shown by experiments with a cysteine-free HMGB1 mutant. Release of Prdx1 and 2 is not prevented by inhibitors of the classical secretory pathway; instead, both Prdx1 and 2 are released in exosomes from both HEK cells and monocytic cells. Serum Prdx1 and 2 are also associated with the exosomes. These results describe a novel pathway of protein secretion mediated by cysteine oxidation that underlines the importance of redox-dependent signalling mechanisms in inflammation
Multicenter Prospective Study of Laparoscopic Nissen Fundoplication for Gastroesophageal Reflux Disease in Korea
BACKGROUND/AIMS: This multicenter study aims to evaluate the effect and feasibility of anti-reflux surgery compared with medical treatment for gastroesophageal reflux disease (GERD).
METHODS: Patients with GERD who were undergoing medical treatment with proton pump inhibitors for more than 8 weeks and those who were scheduled to undergo anti-reflux surgery were enrolled. Efficacy of pre-operative medical treatment was evaluated retrospectively and effect of anti-reflux surgery was prospectively evaluated at 1 week and 3 months after surgery. Quality of life (QOL) was also investigated before and after surgery.
RESULTS: Between February and October 2018, 51 patients underwent laparoscopic Nissen fundoplication for treating GERD at 5 hospitals in Korea. Thirty-four patients (66.7%) showed poor proton pump inhibitor response. At 3 months after surgery, heartburn was completely resolved in 87.9% patients and partially improved in 9.1%. Acid regurgitation was completely resolved in 82.9% and partially improved in 11.4%. Atypical extraesophageal symptoms were completely controlled in 45.5% and partially controlled in 36.4%. GERD-related QOL scores at 1 week after surgery significantly improved compared with pre-operative scores. There was no difference in GERD-related QOL scores between 1 week and 3 months after surgery. General QOL measured with European QOL-5 dimensions and health-related QOL instrument with 8 items significantly improved after anti-reflux surgery. Satisfaction with treatment was significantly higher after surgery than before surgery (72.5% vs 11.8%, P < 0.001).
CONCLUSION: Anti-reflux surgery improved GERD symptoms and QOL in patients. Anti-reflux surgery is an effective treatment option compared with medical treatment for GERD patients selected for surgical treatment
The Hubbard model within the equations of motion approach
The Hubbard model has a special role in Condensed Matter Theory as it is
considered as the simplest Hamiltonian model one can write in order to describe
anomalous physical properties of some class of real materials. Unfortunately,
this model is not exactly solved except for some limits and therefore one
should resort to analytical methods, like the Equations of Motion Approach, or
to numerical techniques in order to attain a description of its relevant
features in the whole range of physical parameters (interaction, filling and
temperature). In this manuscript, the Composite Operator Method, which exploits
the above mentioned analytical technique, is presented and systematically
applied in order to get information about the behavior of all relevant
properties of the model (local, thermodynamic, single- and two- particle ones)
in comparison with many other analytical techniques, the above cited known
limits and numerical simulations. Within this approach, the Hubbard model is
shown to be also capable to describe some anomalous behaviors of the cuprate
superconductors.Comment: 232 pages, more than 300 figures, more than 500 reference
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