905 research outputs found
Development of a tool to optimize the performance of a Maui Cluster Scheduler
The use of Linux cluster computing in a scientific and heterogeneous environment has been growing very fast in the past years. The often conflicting user’s requests of shared resources are quite difficult to satisfy for the administrators, and, usually, lower the overall system efficiency. In this scenario a new tool to study and
optimize the Maui Cluster Scheduler has been developed together with a new set of metrics to evaluate any given configuration. The main idea is to use the Maui internal simulator, fed by workloads produced either by a real cluster than by an ad hoc one, to test several scheduler configurations and then, using a genetic algorithm, to choose the best solution. In this work the architecture of the proposed tool is described together with the first results
Cell-clearing systems bridging repeat expansion proteotoxicity and neuromuscular junction alterations in ALS and SBMA
The coordinated activities of autophagy and the ubiquitin proteasome system (UPS) are key to preventing the aggregation and toxicity of misfold-prone proteins which manifest in a number of neurodegenerative disorders. These include proteins which are encoded by genes containing nucleotide repeat expansions. In the present review we focus on the overlapping role of autophagy and the UPS in repeat expansion proteotoxicity associated with chromosome 9 open reading frame 72 (C9ORF72) and androgen receptor (AR) genes, which are implicated in two motor neuron disorders, amyotrophic lateral sclerosis (ALS) and spinal-bulbar muscular atrophy (SBMA), respectively. At baseline, both C9ORF72 and AR regulate autophagy, while their aberrantly-expanded isoforms may lead to a failure in both autophagy and the UPS, further promoting protein aggregation and toxicity within motor neurons and skeletal muscles. Besides proteotoxicity, autophagy and UPS alterations are also implicated in neuromuscular junction (NMJ) alterations, which occur early in both ALS and SBMA. In fact, autophagy and the UPS intermingle with endocytic/secretory pathways to regulate axonal homeostasis and neurotransmission by interacting with key proteins which operate at the NMJ, such as agrin, acetylcholine receptors (AChRs), and adrenergic beta2 receptors (B2-ARs). Thus, alterations of autophagy and the UPS configure as a common hallmark in both ALS and SBMA disease progression. The findings here discussed may contribute to disclosing overlapping molecular mechanisms which are associated with a failure in cell-clearing systems in ALS and SBMA
Graph clustering and portable X-Ray Fluorescence: An application for in situ, fast and preliminary classification of transport amphoras
In the last decade, numerous papers have been delivered on the potential of portable X-Ray Fluorescence (XRF) in archaeological ceramics. Additionally, new chemometric methods have been proposed to manage chemical dataset and facilitate the use of geochemical discrimination for provenance classification of ancient ceramics. In this contribute, the potential of portable Energy Dispersive X-Ray Fluorescence (ED-XRF) analysis and chemical data processing by Graph Clustering is evaluated for provenance classification of archaeological potteries, discussing possible merits and limits of the employed routine. A ceramic assemblage represented by seventy-three transport amphorae classified by typological analysis have been used as testing materials; spectra have been collected on samples simulating in situ analysis conditions (e.g. on fresh cut surfaces without any preparation) and Graph Clustering method has been applied in chemical data processing; comparison with classical Cluster Analysis (CA) and Principal Component Analysis (PCA) is also evaluated. The obtained results favor the use of Graph Clustering for a preliminary classification of ceramics, which can be chemically analyzed in easy, fast and non-destructive way. With a 75.35% of correct attribution, the study shows the suitability of portable ED-XRF in rapid screening of a large number of ceramic samples usually recovered in the framework of archaeological excavation. Misclassifications have been mostly verified for samples exhibiting a coarse-grained clay paste, suggesting that the method is particularly suitable for fine-grained ceramic materials
Duration of remission after halving of the etanercept dose in patients with ankylosing spondylitis: a randomized, prospective, long-term, follow-up study
Fabrizio Cantini, Laura Niccoli, Emanuele Cassarà, Olga Kaloudi, Carlotta NanniniDivision of Rheumatology, Misericordia e Dolce Hospital, Prato, ItalyBackground: The aim of this study was to evaluate the proportion of patients with ankylosing spondylitis maintaining clinical remission after reduction of their subcutaneous etanercept dose to 50 mg every other week compared with that in patients receiving etanercept 50 mg weekly.Methods: In the first phase of this randomized, prospective, follow-up study, all biologic-naïve patients identified between January 2005 and December 2009 as satisfying the modified New York clinical criteria for ankylosing spondylitis treated with etanercept 50 mg weekly were evaluated for disease remission in January 2010. In the second phase, patients meeting the criteria for remission were randomized to receive subcutaneous etanercept as either 50 mg weekly or 50 mg every other week. The randomization allocation was 1:1. Remission was defined as Bath Ankylosing Spondylitis Disease Activity Index < 4, no extra-axial manifestations of peripheral arthritis, dactylitis, tenosynovitis, or iridocyclitis, and normal acute-phase reactants. The patients were assessed at baseline, at weeks 4 and 12, and every 12 weeks thereafter. The last visit constituted the end of the follow-up.Results: During the first phase, 78 patients with ankylosing spondylitis (57 males and 21 females, median age 38 years, median disease duration 12 years) were recruited. In January 2010, after a mean follow-up of 25 ± 11 months, 43 (55.1%) patients achieving clinical remission were randomized to one of the two treatment arms. Twenty-two patients received etanercept 50 mg every other week (group 1) and 21 received etanercept 50 mg weekly (group 2). At the end of follow-up, 19 of 22 (86.3%) subjects in group 1 and 19 of 21 (90.4%) in group 2 were still in remission, with no significant difference between the two groups. The mean follow-up duration in group 1 and group 2 was 22 ± 1 months and 21 ± 1.6 months, respectively.Conclusion: Remission of ankylosing spondylitis is possible in at least 50% of patients treated with etanercept 50 mg weekly. After halving of the etanercept dose, remission is maintained in a high percentage of patients during long-term follow-up, with important economic implications.Keywords: ankylosing spondylitis, anti-tumor necrosis factor, etanercept, remission, dose reductio
First test of a high voltage feedthrough for liquid Argon TPCs connected to a 300 kV power supply
Voltages above a hundred kilo-volt will be required to generate the drift
field of future very large liquid Argon Time Projection Chambers. The most
delicate component is the feedthrough whose role is to safely deliver the very
high voltage to the cathode through the thick insulating walls of the cryostat
without compromising the purity of the argon inside. This requires a
feedthrough that is typically meters long and carefully designed to be vacuum
tight and have small heat input. Furthermore, all materials should be carefully
chosen to allow operation in cryogenic conditions. In addition, electric fields
in liquid argon should be kept below a threshold to reduce risks of discharges.
The combination of all above requirements represents significant challenges
from the design and manufacturing perspective. In this paper, we report on the
successful operation of a feedthrough satisfying all the above requirements.
The details of the feedthrough design and its manufacturing steps are provided.
Very high voltages up to unprecedented voltages of -300 kV could be applied
during long periods repeatedly. A source of instability was observed, which was
specific to the setup configuration which was used for the test and not due to
the feedthrough itself.Comment: 13 pages, 9 figure
SARS-CoV-2 Mproinhibition by a zinc ion: structural features and hints for drug design
The first structure of the SARS-CoV-2 main protease in complex with an isolated zinc ion provides solid ground for the design of potent and selective metal-conjugated inhibitors
Algebraic Bethe Ansatz for the two species ASEP with different hopping rates
An ASEP with two species of particles and different hopping rates is
considered on a ring. Its integrability is proved and the Nested Algebraic
Bethe Ansatz is used to derive the Bethe Equations for states with arbitrary
numbers of particles of each type, generalizing the results of Derrida and
Evans. We present also formulas for the total velocity of particles of a given
type and their limit for large size of the system and finite densities of the
particles.Comment: 14 page
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