17,797 research outputs found
Forced vibration analysis of rotating cyclic structures in NASTRAN
A new capability was added to the general purpose finite element program NASTRAN Level 17.7 to conduct forced vibration analysis of tuned cyclic structures rotating about their axis of symmetry. The effects of Coriolis and centripetal accelerations together with those due to linear acceleration of the axis of rotation were included. The theoretical, user's, programmer's and demonstration manuals for this new capability are presented
ADAR enzyme and miRNA story: A nucleotide that can make the difference
Adenosine deaminase acting on RNA (ADAR) enzymes convert adenosine (A) to inosine (I) in double-stranded (ds) RNAs. Since Inosine is read as Guanosine, the biological consequence of ADAR enzyme activity is an A/G conversion within RNA molecules. A-to-I editing events can occur on both coding and non-coding RNAs, including microRNAs (miRNAs), which are small regulatory RNAs of ~20-23 nucleotides that regulate several cell processes by annealing to target mRNAs and inhibiting their translation. Both miRNA precursors and mature miRNAs undergo A-to-I RNA editing, affecting the miRNA maturation process and activity. ADARs can also edit 3' UTR of mRNAs, further increasing the interplay between mRNA targets and miRNAs. In this review, we provide a general overview of the ADAR enzymes and their mechanisms of action as well as miRNA processing and function. We then review the more recent findings about the impact of ADAR-mediated activity on the miRNA pathway in terms of biogenesis, target recognition, and gene expression regulation
The rise of an ionized wind in the Narrow Line Seyfert 1 Galaxy Mrk 335 observed by XMM-Newton and HST
We present the discovery of an outflowing ionized wind in the Seyfert 1
Galaxy Mrk 335. Despite having been extensively observed by most of the largest
X-ray observatories in the last decade, this bright source was not known to
host warm absorber gas until recent XMM-Newton observations in combination with
a long-term Swift monitoring program have shown extreme flux and spectral
variability. High resolution spectra obtained by the XMM-Newton RGS detector
reveal that the wind consists of three distinct ionization components, all
outflowing at a velocity of 5000 km/s. This wind is clearly revealed when the
source is observed at an intermediate flux state (2-5e-12 ergs cm^-2 s^-1). The
analysis of multi-epoch RGS spectra allowed us to compare the absorber
properties at three very different flux states of the source. No correlation
between the warm absorber variability and the X-ray flux has been determined.
The two higher ionization components of the gas may be consistent with
photoionization equilibrium, but we can exclude this for the only ionization
component that is consistently present in all flux states (log(xi)~1.8). We
have included archival, non-simultaneous UV data from HST (FOS, STIS, COS) with
the aim of searching for any signature of absorption in this source that so far
was known for being absorption-free in the UV band. In the COS spectra obtained
a few months after the X-ray observations we found broad absorption in CIV
lines intrinsic to the AGN and blueshifted by a velocity roughly comparable to
the X-ray outflow. The global behavior of the gas in both bands can be
explained by variation of the covering factor and/or column density, possibly
due to transverse motion of absorbing clouds moving out of the line of sight at
Broad Line Region scale.Comment: 24 pages, 12 figures, ApJ accepte
A predictive and adaptive control strategy to optimize the management of integrated energy systems in buildings
The management of integrated energy systems in buildings is a challenging task that classical control approaches usually fail to address. The present paper analyzes the effect of the implementation of a reinforcement learning-based control strategy in an office building characterized by integrated energy systems with on-site electricity generation and storage technologies. The objective of the proposed controller is to minimize the operational cost to meet the cooling demand exploiting thermal energy storage and battery system considering a time-of-use electricity price schedule and local PV production. Two control solutions, a Soft-Actor-Critic agent coupled with a rule-based controller, and a fully rule-based control strategy, used as a baseline, are tested and compared considering various configurations of battery energy storage system capacities, and thermal energy storage sizes. Results show that the proposed control strategy leads to a reduction of operational energy costs respect to the fully rule-based control ranging from 39.5% and 84.3% among different configurations. Moreover the advanced control strategy improves the on-site PV utilization leading to an average increasing of self-sufficiency and self-consumption of 40% among different scenarios. The baseline control strategy results more sensitive to the size of storage whereas the proposed control achieves high savings also when smaller capacities of battery energy storage systems and sizes of thermal energy storage are implemented. The outcomes of the work prove the impact of implementation of advanced control as a way to optimize energy costs with a comprehensive view of the whole integrated energy system considering both thermal and electrical energy storage operation
Expansion of the energy of the ground state of the Gross-Pitaevskii equation in the Thomas-Fermi limit
From the asymptotic expansion of the ground state of the Gross-Pitaevskii
equation in the Thomas--Fermi limit given by Gallo and Pelinovsky in a previous
work, we infer an asymptotic expansion of the kinetic, potential and total
energy of the ground state. In particular, we give a rigorous proof of the
expansion of the kinetic energy calculated by Dalfovo, Pitaevskii and Stringari
in the case where the space dimension is 3. Moreover, we calculate one more
term in this expansion, and we generalize the result to space dimensions 1 and
2
Modulation of microRNA editing, expression and processing by ADAR2 deaminase in glioblastoma.
Background: ADAR enzymes convert adenosines to inosines within double-stranded RNAs, including microRNA
(miRNA) precursors, with important consequences on miRNA retargeting and expression. ADAR2 activity is impaired
in glioblastoma and its rescue has anti-tumoral effects. However, how ADAR2 activity may impact the miRNome
and the progression of glioblastoma is not known.
Results: By integrating deep-sequencing and array approaches with bioinformatics analyses and molecular studies,
we show that ADAR2 is essential to edit a small number of mature miRNAs and to significantly modulate the
expression of about 90 miRNAs in glioblastoma cells. Specifically, the rescue of ADAR2 activity in cancer cells recovers
the edited miRNA population lost in glioblastoma cell lines and tissues, and rebalances expression of onco-miRNAs and
tumor suppressor miRNAs to the levels observed in normal human brain. We report that the major effect of ADAR2 is
to reduce the expression of a large number of miRNAs, most of which act as onco-miRNAs. ADAR2 can edit miR-222/221
and miR-21 precursors and decrease the expression of the corresponding mature onco-miRNAs in vivo and in vitro, with
important effects on cell proliferation and migration.
Conclusions: Our findings disclose an additional layer of complexity in miRNome regulation and provide information
to better understand the impact of ADAR2 editing enzyme in glioblastoma. We propose that ADAR2 is a key factor for
maintaining edited-miRNA population and balancing the expression of several essential miRNAs involved in cancer
Beta-Lactamase Repressor BlaI Modulates Staphylococcus aureus Cathelicidin Antimicrobial Peptide Resistance and Virulence.
BlaI is a repressor of BlaZ, the beta-lactamase responsible for penicillin resistance in Staphylococcus aureus. Through screening a transposon library in S. aureus Newman for susceptibility to cathelicidin antimicrobial peptide, we discovered BlaI as a novel cathelicidin resistance factor. Additionally, through integrational mutagenesis in S. aureus Newman and MRSA Sanger 252 strains, we confirmed the role of BlaI in resistance to human and murine cathelidicin and showed that it contributes to virulence in human whole blood and murine infection models. We further demonstrated that BlaI could be a target for innate immune-based antimicrobial therapies; by removing BlaI through subinhibitory concentrations of 6-aminopenicillanic acid, we were able to sensitize S. aureus to LL-37 killing
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