642 research outputs found
Effects of hadronic potentials on elliptic flows in relativistic heavy ion collisions
Within the framework of a multiphase transport (AMPT) model that includes
both initial partonic and final hadronic interactions, we show that including
mean-field potentials in the hadronic phase leads to a splitting of the
elliptic flows of particles and their antiparticles, providing thus a plausible
explanation of the different elliptic flows between and ,
and , and and observed in recent Beam Energy Scan (BES)
program at the Relativistic Heavy-Ion Collider (RHIC).Comment: 5 pages, 7 figure
Zeroth-Order Alternating Gradient Descent Ascent Algorithms for a Class of Nonconvex-Nonconcave Minimax Problems
In this paper, we consider a class of nonconvex-nonconcave minimax problems,
i.e., NC-PL minimax problems, whose objective functions satisfy the
Polyak-\Lojasiewicz (PL) condition with respect to the inner variable. We
propose a zeroth-order alternating gradient descent ascent (ZO-AGDA) algorithm
and a zeroth-order variance reduced alternating gradient descent ascent
(ZO-VRAGDA) algorithm for solving NC-PL minimax problem under the deterministic
and the stochastic setting, respectively. The number of iterations to obtain an
-stationary point of ZO-AGDA and ZO-VRAGDA algorithm for solving
NC-PL minimax problem is upper bounded by and
, respectively. To the best of our knowledge,
they are the first two zeroth-order algorithms with the iteration complexity
gurantee for solving NC-PL minimax problems
Information Filtering on Coupled Social Networks
In this paper, based on the coupled social networks (CSN), we propose a
hybrid algorithm to nonlinearly integrate both social and behavior information
of online users. Filtering algorithm based on the coupled social networks,
which considers the effects of both social influence and personalized
preference. Experimental results on two real datasets, \emph{Epinions} and
\emph{Friendfeed}, show that hybrid pattern can not only provide more accurate
recommendations, but also can enlarge the recommendation coverage while
adopting global metric. Further empirical analyses demonstrate that the mutual
reinforcement and rich-club phenomenon can also be found in coupled social
networks where the identical individuals occupy the core position of the online
system. This work may shed some light on the in-depth understanding structure
and function of coupled social networks
The Influence of Court Surfaces on Lower Limb Muscle Activation of Tennis Run-and-Stroke
This study aimed to examine the characteristics of lower extremity muscle activity between different tennis court surfaces. Six male right-handed elite tennis players were recruited, and their electromyography activity (EMG) during open stance running forehand were collected. Average activity level of rectus femoris (RF), biceps femoris (BF), gastrocnemius (GAS), tibialis anterior (TA) from the lead leg, which normalized by maximal voluntary isometric contractions (MVC) was recorded under different situation (hard court, grass court, clay court). Our study demonstrates that GAS was significantly different and the activation level was greater on a hard court than on clay (p = .005). Tennis players should enhance their gastrocnemius muscle performance when matching from clay to hard court to avoid a higher level of gastrocnemius activation when adapting to a different court, which could lead to an injury.
KEYWORDS: Grand Slam, training, EMG, performanc
Polarization-based cyclic weak value metrology for angular velocity measurement
Weak value has been proved to amplify the detecting changes of the meters at
the cost of power due to post-selection. Previous power-recycling schemes
enable the failed post-selection photons to be reselected repeatedly, thus
surpassing the upper noise limit and improving the precision of interferometric
systems. Here we introduce three cyclic methods to improve the sensitivity of
polarization-based weak-value-based angular velocity measurement: power-,
signal- and dual-recycling schemes. By inserting one or two partially
transmitting mirrors inside the system, both the power and precision of
detected signals are greatly enhanced, and the dual-recycling scheme has wider
optimal region than that of power- or signal-recycling schemes. Compared to
non-polarization schemes, polarization-based schemes enjoy lower optical loss
and unique cyclic directions. These reduce the crosstalk among different paths
of light and, theoretically, eliminate the walk-off effect, thus towering in
both theoretical performance and application.Comment: 7 pages, 3 figure
Study on Burr Formation at the Top Edge in Rectangular Groove Cutting
Previous research on burr formation in machining operations has usually been limited to the study of the rollover burr in the cutting direction. In this paper, a 3D finite element model to simulate rectangular groove cutting operation has been developed using commercial finite element software, employing experimentally determined mechanical properties at elevated strain rates and temperatures. The plastic deformation behavior and three-dimensional burr formation during rectangular groove cutting is investigated. The simulated burr profile and cutting force prove that the developed model can capture the thermo-mechanical mechanisms in rectangular groove cutting and can simulate burr development with considerable accuracy. The study concentrates on the influence of cutting parameters on burr formation which are also conducted. The results show that the feed rate and rake angle are the cutting parameters which have a major influence on burr size in the groove cutting operation. And the effect of cutting velocity and minor clearance angle in the traditional range on burr size are quite limited
Silencing METTL14 alleviates liver injury in non-alcoholic fatty liver disease by regulating mitochondrial homeostasis
Mitochondrial dysfunction is an important pathogenic factor in non-alcoholic fatty liver disease (NAFLD). Methyltransferase-like 14 (METTL14) has been implicated in mitochondrial fission processes. This research aimed to investigate the mechanism of METTL14 in the mitochondrial function of NAFLD. We first established NAFLD mouse models and cell models, recording body and liver weights and examining pathological changes in liver tissues. Subsequently, serum levels of liver function indices (aspartate aminotransferase [AST], alanine aminotransferase [ALT], total cholesterol [TC], and triglycerides [TG]), inflammatory markers (tumor necrosis factor-alpha [TNF-α], interleukin [IL]-6, and IL-1β), and mitochondrial dysfunction indicators (fission 1 protein [Fis1], dynamin-related protein 1 [Drp1], mitofusin 2 [Mfn2], SID1 transmembrane family member 2 [SIDT2], and mitochondrial membrane potential [MMP]) in the liver and cells were evaluated. The N6-methyladenosine (m6A) modification level of primary microRNA (pri-miRNA) and m6A enrichment on pri-miR-34a were quantified. Co-immunoprecipitation and dual-luciferase reporter gene assays were utilized to validate gene interactions. Our findings revealed highly elevated METTL14 expression in NAFLD mouse and cell models. Silencing METTL14 reduced weight gain and mitigated adverse liver function indices, inflammation, hepatic steatosis, and structural damage in NAFLD mice. It also led to a decrease in Fis1/Drp1 levels and an increase in MMP/Mfn2 in the liver and cells. Moreover, METTL14 increased the m6A level, promoting the binding of DiGeorge syndrome critical region 8 (DGCR8) to pri-miR-34a, which enhanced miR-34a-5p expression. Databases and dual-luciferase reporter gene assays indicated that miR-34a-5p could suppress SIDT2 expression. The overexpression of miR-34a-5p or inhibition of SIDT2 expression negated the alleviative effects of METTL14 silencing on mitochondrial homeostasis imbalance. In conclusion, METTL14, through m6A modification, modulates the miR-34a-5p/SIDT2 axis, impairing mitochondrial homeostasis in NAFLD
iPTF14hls in the circumstellar medium interaction model: A promising candidate for a pulsational pair-instability supernova
iPTF14hls is a luminous Type II supernova (SN) with a bumpy light curve that
remains debated for its origin. It maintains roughly a constant effective
temperature and luminosity since discovery for about 600 days, followed by a
slow decay. On \ days post discovery the light curve transitions to
a very steep decline. A spectrum taken during this steep decline phase shows
clear signatures of shock interaction with dense circumstellar medium (CSM).
Here we explore the possibility of iPTF14hls as an interaction-powered SN. The
light curve of iPTF14hls can be fitted with wind-like CSMs. Analytic modeling
indicates that iPTF14hls may have undertaken six episodes of mass loss during
the last . Assuming that the 1954 eruption triggered the
last mass-loss episode, the stellar-wind velocity is determined to be
, depending on different models. Mass loss
rates are in the range . The inferred
total mass of ejecta and CSMs () supports the idea that iPTF14hls may be a candidate for a
(pulsational) pair-instability SN. Discovery and observations of more similar
stellar explosions will help understand these peculiar SNe.Comment: 12 pages, 4 figures. Accepted for publication in Ap
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Pluripotency-associated genes in human nasopharyngeal carcinoma CNE-2 cells are reactivated by a unique epigenetic sub-microenvironment.
RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: There is increasing evidence that cancers contain their own stem-like cells, and particular attention has been paid to one subset of cancer-stem cells termed side population (SP). Stem cells under normal physical conditions are tightly controlled by their microenvironment, however, the regulatory role of the microenvironment surrounding cancer stem cells is not well characterized yet. In this study we found that the phenotype of SP can be "generated" by macrophage-like cells under conditioned culture. Furthermore the gene regulation pathway involved in cellular reprogramming process was investigated. METHODS: The selection and identification of SP in 50 CNE-2 single cell clones were performed by flow cytometry. The transwell assay and immunofluorescence staining were used to measure migration and cancer stem cell characters of non-SP single clone cells cultured with conditioned medium respectively. The subtraction suppression hybridization (SSH) technique and northern blotting analysis was applied to explore the pluripotency-associated genes under a unique epigenetic sub-microenvironment. RESULTS: Among 50 clones, only one did not possess SP subpopulation while others did. The non-SP cells induced by macrophage-like cells showed more aggressive characters, which increased cell migration compared with the control cells and showed some fraction of SP phenotype. These cells expressed distinguished level of pluripotency-associated genes such as ADP-ribosylation factor-like 6 interacting protein (ARMER), poly (rC) binding protein 1 (PCBP1) and pyruvate dehydrogenase E1-beta subunit (PDHB) when subjected to the environment. CONCLUSION: To our knowledge, this is the first study to demonstrate that non-SP single-clone cells can be induced to generate a SP phenotype when they are cultured with conditioned medium of macrophage-like cells, which is associated with the reactivation of pluripotency-associated genes.Peer Reviewe
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