253 research outputs found
Voter model on a directed network: Role of bidirectional opinion exchanges
The voter model with the node update rule is numerically investigated on a
directed network. We start from a directed hierarchical tree, and split and
rewire each incoming arc at the probability . In order to discriminate the
better and worse opinions, we break the symmetry () by
giving a little more preference to the opinion . It is found that
as becomes larger, introducing more complicated pattern of information flow
channels, and as the network size becomes larger, the system eventually
evolves to the state in which more voters agree on the better opinion, even
though the voter at the top of the hierarchy keeps the worse opinion. We also
find that the pure hierarchical tree makes opinion agreement very fast, while
the final absorbing state can easily be influenced by voters at the higher
ranks. On the other hand, although the ordering occurs much slower, the
existence of complicated pattern of bidirectional information flow allows the
system to agree on the better opinion.Comment: 5 pages, 3 figures, Phys. Rev. E (in press
Double resonance in the infinite-range quantum Ising model
We study quantum resonance behavior of the infinite-range kinetic Ising model
at zero temperature. Numerical integration of the time-dependent Schr\"odinger
equation in the presence of an external magnetic field in the direction is
performed at various transverse field strengths . It is revealed that two
resonance peaks occur when the energy gap matches the external driving
frequency at two distinct values of , one below and the other above the
quantum phase transition. From the similar observations already made in
classical systems with phase transitions, we propose that the double resonance
peaks should be a generic feature of continuous transitions, for both quantum
and classical many-body systems.Comment: 4 pages, 5 figure
Reentrant phase transition in a predator-prey model
We numerically investigate the six-species predator-prey game in complex
networks as well as in -dimensional hypercubic lattices with .
The interaction topology of the six species contains two loops, each of which
is composed of cyclically predating three species. As the mutation rate is
lowered below the well-defined phase transition point, the symmetry
related with the interchange of the two loops is spontaneously broken, and it
has been known that the system develops the defensive alliance in which three
cyclically predating species defend each other against the invasion of other
species. In the small-world network structure characterized by the rewiring
probability , the phase diagram shows the reentrant behavior as
is varied, indicating a twofold role of the shortcuts. In
-dimensional regular hypercubic lattices, the system also exhibits the
reentrant phase transition as is increased. We identify universality class
of the phase transition and discuss the proper mean-field limit of the system.Comment: 8 pages, 7 figures, Phys. Rev. E (in press
Outcomes of endovascular treatment for aortic pseudoaneurysm in Behcet's disease
ObjectiveTo evaluate the effectiveness of endovascular stent grafting for surgical management of aortic pseudoaneurysm in patients with Behcet's disease (BD).MethodsWe present a single-institution retrospective cohort of patients with aortic pseudoaneurysm and BD treated with aortic stent grafting. Computed tomography imaging was obtained preoperatively in all patients and once within 2 weeks postoperatively, and then annually. Clinical follow-up and erythrocyte sedimentation rate were used to follow BD activity. Immunosuppressant therapy was instituted prior to endovascular treatment unless a contraindication existed.ResultsFrom 1998 to 2012, 10 patients (eight male, two female; median age, 39) with BD and aortic pseudoaneurysm were treated with endovascular stent grafting at this institution. Ninety percent of these patients received immunosuppressive therapy before and after surgical treatment. The median follow-up period was 57 months (interquartile range, 43-72). The locations of the 12 pseudoaneurysms treated in this cohort were infrarenal abdominal aorta (seven), descending thoracic aorta (four), and aortic arch (one). Median pseudoaneurysm size was 4.5 cm (interquartile range, 3.4-5.9). At long-term follow-up, complete resolution of the aortic pseudoaneurysm was noted in all patients. No endoleaks occurred. Newly developed pseudoaneurysm at the distal margin of the stent graft was noted in one patient 17 months after the stent graft procedure. One patient required a subsequent stent graft placement for an expanding pseudoaneurysm of the subclavian artery. No patient deaths occurred during the follow-up period.ConclusionsEndovascular treatment of aortic pseudoaneurysm with stent-grafting in patients with BD is safe and effective with long-term durability
Comparative Interactomes of VRK1 and VRK3 with Their Distinct Roles in the Cell Cycle of Liver Cancer
Vaccinia-related kinase 1 (VRK1) and VRK3 are members of the VRK family of serine/threonine kinases and are principally localized in the nucleus. Despite the crucial roles of VRK1/VRK3 in physiology and disease, the molecular and functional interactions of VRK1/VRK3 are poorly understood. Here, we identified over 200 unreported VRK1/VRK3-interacting candidate proteins by affinity purification and LC-MS/MS. The networks of VRK1 and VRK3 interactomes were found to be associated with important biological processes such as the cell cycle, DNA repair, chromatin assembly, and RNA processing. Interactions of interacting proteins with VRK1/VRK3 were confirmed by biochemical assays. We also found that phosphorylations of XRCC5 were regulated by both VRK1/VRK3, and that of CCNB1 was regulated by VRK3. In liver cancer cells and tissues, VRK1/VRK3 were highly upregulated and its depletion affected cell cycle progression in the different phases. VRK3 seemed to affect S phase progression and G2 or M phase entry and exit, whereas VRK1 affects G1/S transition in the liver cancer, which could be explained by different interacting candidate proteins. Thus, this study not only provides a resource for investigating the unidentified functions of VRK1/VRK3, but also an insight into the regulatory roles of VRK1/VRK3 in biological processes.11Ysciescopuskc
Gene silencing in HIV-1 latency by polycomb repressive group
<p>Abstract</p> <p>Background</p> <p>The persistence of latently Human immunodeficiency virus-1 (HIV-1) infected cellular reservoirs in resting CD4<sup>+ </sup>T cells is a major obstacle to HIV-1 eradication. The detailed mechanism of HIV-1 latency remains unclear. We investigated histones and their post-translational modification associated with HIV-1 latency in novel HIV-1 latently infected cell lines established previously, NCHA cells.</p> <p>Methods</p> <p>To examine histones and their modification linked with HIV-1 latency, the expression profiles for core histone proteins and histone deacetylases (HDACs) in NCHA cells were characterized by RT-PCR, ELISA, and western blot. The levels of histone acetylation and methylation at histone H3 Lys<sup>9 </sup>(H3K9) and Lys<sup>27 </sup>(H3K27) in HIV-1 latently infected cells were analyzed by western blot and chromatin immunoprecipitation-sequencing (ChIP-seq).</p> <p>Results</p> <p>The expression levels for four core histone proteins (H2A, H2B, H3 and H4) and HDACs (HDAC1-8) in NCHA cells were not significantly different from those in their parental cells. Histone H3K9 and H3K27 acetylations in NCHA cells showed no difference in parental and NCHA cells, whereas the levels of di- and tri-methylation were increased in NCHA cells. The expression of EED which is a component of polycomb repressive complex 2 (PRC2), and BMI1 and RING2 which are constituents of PRC1, were upregulated in NCHA cells. In addition, more ubiquitylation at histone H2A was detected in NCHA cells.</p> <p>Conclusions</p> <p>Our results suggest that tri-methylation of histone H3K27 and H2A ubiquitylation via polycomb group protein may play a crucial role in epigenetic silencing accounting for HIV-1 latency in NCHA cells.</p
Coxiella burnetii in Bulk Tank Milk Samples, United States
Dairy cattle are a primary reservoir of Coxiella burnetii, which causes Q fever. However, no recent nationwide studies have assessed the prevalence and risks of Q fever in dairy cattle. We report ≥94% prevalence in samples of bulk tank milk from U.S. dairy herds tested during the past 3 years
Migrated remnant bioresorbable scaffolds in a left main bifurcation lesion: Insights from optical coherence tomography
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