1,353 research outputs found
Signatures of afterglows from light dark matter boosted by supernova neutrinos in current and future large underground detectors
Supernova neutrino boosted dark matter (SN BDM) and its afterglow effect
have been shown to be a promising signature for beyond Standard Model (bSM)
physics. The time-evolution feature of SN BDM allows for possibly direct
inference of DM mass , and results in significant background
suppression with improving sensitivity. This paper extends the earlier study
and provides a general framework for computing the SN BDM fluxes for a
supernova that occurs at any location in our galaxy. A bSM
model with its gauge boson coupling to both DM and the
second and third generation of leptons is considered, which allows for both
DM- and DM- interactions. Detailed analysis of the temporal profile,
angular distribution, and energy spectrum of the SN BDM are performed.
Unique signatures in SN BDM allowing extraction of and detail
features that contain information of the underlying interaction type are
discussed. Expected sensitivities on the above new physics model from
Super-Kamiokande, Hyper-Kamiokande, and DUNE detections of BDM events induced
by the next galactic SN are derived and compared with the existing bounds.Comment: 17 pages, 15 figures, 1 table, 5 appendice
Effect of Post Heated TiN Coating on Pitting Corrosion of Austenitic Stainless Steel
This study used cathodic arc deposition technique to coat TiN film on 316L austenitic stainless steel, and then the coated specimens were heat-treated at the different temperatures. Observation of coating morphology and corrosion tests were conducted for exploring the effect of post-heating temperature on composition, microstructure, and corrosion behavior of the coatings. The results showed when the heating temperature was up to the range of 500-600 oC, a Ti-N-O mixed film consisting of the two TiO2 and TiN phases was formed on the outer layer. Particular, the film heated at 500 oC had a dense structure as well as homogeneous chemical composition. Such the result could effectively inhibit pitting corrosion of 316L stainless steel in 3.5 wt% NaCl and 10 vol% HCl solutions
Alleviating Interference through Cognitive Radio for LTE-Advanced Network
In the LTE-Advanced network, some femtocells are deployed within a macroecell for improving throughput of indoor user equipments (UEs), which are referred to as femtocell UEs (FUEs). Cross-tier interference is an important issue in this deployment, which may significantly impact signal quality between Macrocell Base Stations (MBSs) and Macrocell User Equipments (MUEs), especially for MUEs near the femtocell. To relieve this problem, the Third Generation Partnership Project Long Term Evolution-Advanced (3GPP LTE-Advanced) de fined the cognitive radio enhanced femtocell to coordinate interference for LTE-Advanced Network. Cognitive radio femtocells have the ability to sense radio environment to obtain radio parameters. In this paper, we investigated the performance of existing schemes based on fractional frequency reuse. Therefore, we proposed a scheme with cognitive radio technology to improve the performance of fractional fre-quency reuse scheme. Simulation results showed that our scheme can effectively enhance average downlink throughput of FUEs as well as the total downlink throughput in LTE-Advanced Networks
Compact Dark Objects in Neutron Star Mergers
We estimate the long-lasting gravitational wave (GW) emission of compact dark
objects following a binary neutron-star (NS) merger. We consider compact dark
objects, which initially reside in the centers of NSs and which may consist of
self-interacting dark matter (DM). By approximating the compact dark objects as
test particles, we model the merging of NS binaries hosting DM components with
three-dimensional relativistic simulations. Our simulation results suggest that
the DM components remain gravitationally bound and orbit inside the merger
remnant with orbital separations of typically a few km. The subsequent orbital
motion of the DM components generates a GW signal with frequencies in the range
of a few kHz. When considering a range of different binary masses and
high-density equations of state (EoS), we find that the GW frequency of the
orbiting DM components scales with the compactness of NSs. Similarly, we find
relations between the DM GW frequency and the dominant postmerger GW frequency
of the stellar fluid or the tidal deformability, which quantifies EoS effects
during the binary inspiral. Hence, a measurement of these quantities can be
used to specify the frequency range of the GW emission by DM. Under the
assumption that GW back reaction is the only relevant dissipative process, the
GW signal may last between seconds and years depending on the mass of the DM
component. We estimate the detectability of the GW signals and find that DM
components in NS mergers may only be detectable with existing and projected GW
instruments if the dark objects are as massive as about 0.01 to 0.1 M_sun. We
emphasize that the GW emission is limited by the lifetime of the remnant. A
forming black hole will immediately swallow the DM objects because their orbits
are smaller than the innermost stable circular orbit of the black hole.Comment: 15 pages, 15 figures, submitted to Phys. Rev.
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High thymidylate synthase gene expression predicts poor outcome after resection of hepatocellular carcinoma.
IntroductionPrognosis after resection of hepatocellular carcinoma (HCC) is highly variable. Compared to clinicopathologic factors, the use of molecular markers to predict outcome has not been well studied. We investigated the prognostic importance of thymidylate synthase (TS) gene expression and polymorphisms in patients after resection of HCC.MethodsPatients who underwent complete resection of HCC for whom tissue was available were identified. TS gene expression level and polymorphisms were determined in HCC specimens. Prognostic factors were evaluated using Kaplan-Meier curves and Cox proportional hazard models.ResultsThe study included 67 patients. In univariate analysis, variables that negatively influenced survival included TNM stage, microvascular invasion, and high TS expression. For the high TS expression group, median survival was 54 months and 5-year actuarial survival was 47%. For the low TS expression group, median survival was not reached and the 5-year actuarial survival was 91%. In multivariate analysis, only high TS expression remained an independent predictor of poor survival (HR = 10.77, 95% CI 1.36-84.91; P = 0.02). TS gene polymorphisms were not associated with TS expression or overall survival.ConclusionsHigh TS expression predicts poor outcome after resection of HCC. Molecular markers might be robust predictors of patient outcome after resection of HCC
The antagonism between MCT-1 and p53 affects the tumorigenic outcomes
<p>Abstract</p> <p>Background</p> <p>MCT-1 oncoprotein accelerates p53 protein degradation via a proteosome pathway. Synergistic promotion of the xenograft tumorigenicity has been demonstrated in circumstance of p53 loss alongside MCT-1 overexpression. However, the molecular regulation between MCT-1 and p53 in tumor development remains ambiguous. We speculate that MCT-1 may counteract p53 through the diverse mechanisms that determine the tumorigenic outcomes.</p> <p>Results</p> <p>MCT-1 has now identified as a novel target gene of p53 transcriptional regulation. MCT-1 promoter region contains the response elements reactive with wild-type p53 but not mutant p53. Functional p53 suppresses MCT-1 promoter activity and MCT-1 mRNA stability. In a negative feedback regulation, constitutively expressed MCT-1 decreases p53 promoter function and p53 mRNA stability. The apoptotic events are also significantly prevented by oncogenic MCT-1 in a p53-dependent or a p53-independent fashion, according to the genotoxic mechanism. Moreover, oncogenic MCT-1 promotes the tumorigenicity in mice xenografts of p53-null and p53-positive lung cancer cells. In support of the tumor growth are irrepressible by p53 reactivation <it>in vivo</it>, the inhibitors of p53 (MDM2, Pirh2, and Cop1) are constantly stimulated by MCT-1 oncoprotein.</p> <p>Conclusions</p> <p>The oppositions between MCT-1 and p53 are firstly confirmed at multistage processes that include transcription control, mRNA metabolism, and protein expression. MCT-1 oncogenicity can overcome p53 function that persistently advances the tumor development.</p
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