5,519 research outputs found
Nucleosynthesis in Advective Accretion Disks Around Galactic and Extra-Galactic Black Holes
We compute the nucleosynthesis of materials inside advective disks around
black holes. We show that composition of incoming matter can change
significantly depending on the accretion rate and accretion disks. These works
are improvements on the earlier works in thick accretion disks of Chakrabarti,
Jin & Arnett (1987) in presence of advection in the flow.Comment: Latex pages including figures. Kluwer Style files included. Appearing
in `Observational Evidence for Black Holes in the Universe', ed. Sandip K.
Chakrabarti, Kluwer Academic Publishers (DORDRECHT: Holland
Endoplasmic Reticulum and Mitochondria Contacts Correlate with the Presence and Severity of NASH in Humans
The interaction between the mitochondria and the endoplasmic reticulum (ER) is essential for hepatocyte function. An increase in ER-mitochondria contacts (ERMCs) is associated with various metabolic diseases. Non-alcoholic fatty liver disease (NAFLD) is associated with obesity and type 2 diabetes, and its progressive form non-alcoholic steatohepatitis (NASH) can lead to cirrhosis and hepatocellular carcinoma. However, the role of ERMCs in the progression of NAFL to NASH is still unclear. We assessed whether ERMCs could correlate with NAFLD severity. We used a proximity ligation assay to measure the abundance of ERMCs in liver biopsies from patients with biopsy-proven NAFLD (n = 48) and correlated the results with histological and metabolic syndrome (MetS) features. NAFLD patients were included according to inclusion and exclusion criteria, and then assigned to NAFL (n = 9) and NASH (n = 39) groups. ERMCs density could discriminate NASH from NAFL (sensitivity 61.5%, specificity 100%). ERMCs abundance correlated with hepatocellular ballooning. Moreover, the density of ERMCs increased with an increase in the number of MetS features. In conclusion, ERMCs increased from NAFL to NASH, in parallel with the number of MetS features, supporting a role for this interaction in the pathophysiology of NASH
Epigenetic inactivation of the miR-34a in hematological malignancies
miR-34a is a transcriptional target of p53 and implicated in carcinogenesis. We studied the role of miR-34a methylation in a panel of hematological malignancies including acute leukemia [acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL)], chronic leukemia [chronic lymphocytic leukemia (CLL) and chronic myeloid leukemia (CML)], multiple myeloma (MM) and non-Hodgkin's lymphoma (NHL). The methylation status of miR-34a promoter was studied in 12 cell lines and 188 diagnostic samples by methylation-specific polymerase chain reaction. miR-34a promoter was unmethylated in normal controls but methylated in 75% lymphoma and 37% myeloma cell lines. Hypomethylating treatment led to re-expression of pri-miR-34a transcript in lymphoma cells with homozygous miR-34a methylation. In primary samples at diagnosis, miR-34a methylation was detected in 4% CLL, 5.5% MM samples and 18.8% of NHL at diagnosis but none of ALL, AML and CML (P = 0.011). In MM patients with paired samples, miR-34a methylation status remained unchanged at progression. Amongst lymphoid malignancies, miR-34a was preferentially methylated in NHL (P = 0.018), in particular natural killer (NK)/T-cell lymphoma. In conclusion, amongst hematological malignancies, miR-34a methylation is preferentially hypermethylated in NHL, in particular NK/T-cell lymphoma, in a tumor-specific manner, therefore the role of miR-34a in lymphomagenesis warrants further study. © The Author 2010. Published by Oxford University Press. All rights reserved. For Permissions, please email: [email protected]
NF-κB Signaling Regulates Expression of Epstein-Barr Virus BART MicroRNAs and Long Noncoding RNAs in Nasopharyngeal Carcinoma
published_or_final_versio
Synthesis, structure, and magnetism in the ferromagnet La_{3}MnAs_{5}: Well-separated spin chains coupled via itinerant electrons
In this work, we systematically report the synthesis, structure, and magnetism of a compound of filled
anti-Mn3Si5 type La3MnAs5. It crystallizes in a hexagonal structure with the space group of P63/mcm (193).
The structure consists of face-sharing MnAs6 octahedral chains along the c axis, which are well separated by a
large distance of 8.9913 Å, demonstrating a strong one-dimensional (1D) structural character. Physical property
measurements indicate that La3MnAs5 is a ferromagnetic metal with TC ∼ 112 K. Due to the short-range
intrachain spin coupling, the susceptibility deviates from the Curie-Weiss behavior in a wide temperature
window and the magnetic entropy corresponding to the ferromagnetic transition is significantly lower than that
expected from the fully saturated state. The magnetic critical behavior studies show that La3MnAs5 can be
described by the three-dimensional Heisenberg model. The orbital hybridization between the 1D MnAs6 chain
and intermediate La atom near the Fermi level reveals that the itinerant electrons play a key role in transmitting
spin interaction among the MnAs6 spin chains. Our results indicate that La3MnAs5 is a rare ferromagnetic metal
with well-separated spin chains, which provides a good opportunity to study the mechanism of interchain spin
coupling via itinerant electrons
Resonances in and
A partial wave analysis is presented of and
from a sample of 58M events in the BES II detector. The
is observed clearly in both sets of data, and parameters of the
Flatt\' e formula are determined accurately: (stat)
(syst) MeV/c, MeV/c, . The data also exhibit a strong peak
centred at MeV/c. It may be fitted with and a
dominant signal made from interfering with a smaller
component. There is evidence that the signal is
resonant, from interference with . There is also a state in with MeV/c and
MeV/c; spin 0 is preferred over spin 2. This state, , is
distinct from . The data contain a strong peak due to
. A shoulder on its upper side may be fitted by interference
between and .Comment: 17 pages, 6 figures, 1 table. Submitted to Phys. Lett.
First Measurements of eta_c Decaying into K^+K^-2(pi^+pi^-) and 3(pi^+pi^-)
The decays of eta_c to K^+K^-2(pi^+pi^-) and 3(pi^+pi^-) are observed for the
first time using a sample of 5.8X10^7 J/\psi events collected by the BESII
detector. The product branching fractions are determined to be B(J/\psi-->gamma
eta_c)*B(eta_c-->K^+K^-pi^+pi^-pi^+pi^-)=(1.21+-0.32+-
0.23)X10^{-4}, and (J/\psi-->gamma eta_c)*
B(eta_c-->pi^+pi^-pi^+pi^-pi^+pi^-)= (2.59+-0.32+-0.48)X10^{-4}. The upper
limit for eta_c-->phi pi^+pi^-pi^+pi^- is also obtained as B(J/\psi-->gamma
eta_c)*B(eta_c--> phi pi^+pi^-pi^+pi^-)< 6.03 X10^{-5} at the 90% confidence
level.Comment: 11 pages, 4 figure
Mathematically Gifted Adolescents Have Deficiencies in Social Valuation and Mentalization
Many mathematically gifted adolescents are characterized as being indolent, underachieving and unsuccessful despite their high cognitive ability. This is often due to difficulties with social and emotional development. However, research on social and emotional interactions in gifted adolescents has been limited. The purpose of this study was to observe differences in complex social strategic behaviors between gifted and average adolescents of the same age using the repeated Ultimatum Game. Twenty-two gifted adolescents and 24 average adolescents participated in the Ultimatum Game. Two adolescents participate in the game, one as a proposer and the other as a responder. Because of its simplicity, the Ultimatum Game is an apt tool for investigating complex human emotional and cognitive decision-making in an empirical setting. We observed strategic but socially impaired offers from gifted proposers and lower acceptance rates from gifted responders, resulting in lower total earnings in the Ultimatum Game. Thus, our results indicate that mathematically gifted adolescents have deficiencies in social valuation and mentalization
Transmit Power Minimization for MIMO Systems of Exponential Average BER with Fixed Outage Probability
This document is the Accepted Manuscript version of the following article: Dian-Wu Yue, and Yichuang Sun, ‘Transmit Power Minimization for MIMO Systems of Exponential Average BER with Fixed Outage Probability’, Wireless Personal Communications, Vol. 90 (4): 1951-1970, first available online on 20 June 2016. Under embargo. Embargo end date: 20 June 2017. The final publication is available at Springer via https://link.springer.com/article/10.1007%2Fs11277-016-3432-4This paper is concerned with a wireless multiple-antenna system operating in multiple-input multiple-output (MIMO) fading channels with channel state information being known at both transmitter and receiver. By spatiotemporal subchannel selection and power control, it aims to minimize the average transmit power (ATP) of the MIMO system while achieving an exponential type of average bit error rate (BER) for each data stream. Under the constraints on each subchannel that individual outage probability and average BER are given, based on a traditional upper bound and a dynamic upper bound of Q function, two closed-form ATP expressions are derived, respectively, which can result in two different power allocation schemes. Numerical results are provided to validate the theoretical analysis, and show that the power allocation scheme with the dynamic upper bound can achieve more power savings than the one with the traditional upper bound.Peer reviewe
Nanostructured 3D Constructs Based on Chitosan and Chondroitin Sulphate Multilayers for Cartilage Tissue Engineering
Nanostructured three-dimensional constructs combining layer-by-layer technology (LbL) and template leaching were processed and evaluated as possible support structures for cartilage tissue engineering. Multilayered constructs were formed by depositing the polyelectrolytes chitosan (CHT) and chondroitin sulphate (CS) on either bidimensional glass surfaces or 3D packet of paraffin spheres. 2D CHT/CS multi-layered constructs proved to support the attachment and proliferation of bovine chondrocytes (BCH). The technology was transposed to 3D level and CHT/CS multi-layered hierarchical scaffolds were retrieved after paraffin leaching. The obtained nanostructured 3D constructs had a high porosity and water uptake capacity of about 300%. Dynamical mechanical analysis (DMA) showed the viscoelastic nature of the scaffolds. Cellular tests were performed with the culture of BCH and multipotent bone marrow derived stromal cells (hMSCs) up to 21 days in chondrogenic differentiation media. Together with scanning electronic microscopy analysis, viability tests and DNA quantification, our results clearly showed that cells attached, proliferated and were metabolically active over the entire scaffold. Cartilaginous extracellular matrix (ECM) formation was further assessed and results showed that GAG secretion occurred indicating the maintenance of the chondrogenic phenotype and the chondrogenic differentiation of hMSCs
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