1,126 research outputs found
Altered microRNA and target gene expression related to Tetralogy of Fallot
MicroRNAs (miRNAs) play an important role in guiding development and maintaining function of the human heart. Dysregulation of miRNAs has been linked to various congenital heart diseases including Tetralogy of Fallot (TOF), which represents the most common cyanotic heart malformation in humans. Several studies have identified dysregulated miRNAs in right ventricular (RV) tissues of TOF patients. In this study, we profiled genome-wide the whole transcriptome and analyzed the relationship of miRNAs and mRNAs of RV tissues of a homogeneous group of 22 non-syndromic TOF patients. Observed profiles were compared to profiles obtained from right and left ventricular tissue of normal hearts. To reduce the commonly observed large list of predicted target genes of dysregulated miRNAs, we applied a stringent target prediction pipeline integrating probabilities for miRNA-mRNA interaction. The final list of disease-related miRNA-mRNA pairs comprises novel as well as known miRNAs including miR-1 and miR-133, which are essential to cardiac development and function by regulating KCNJ2, FBN2, SLC38A3 and TNNI1. Overall, our study provides additional insights into post-transcriptional gene regulation of malformed hearts of TOF patients
Quantum critical dynamics of the two-dimensional Bose gas
The dilute, two-dimensional Bose gas exhibits a novel regime of relaxational
dynamics in the regime k_B T > |\mu| where T is the absolute temperature and
\mu is the chemical potential. This may also be interpreted as the quantum
criticality of the zero density quantum critical point at \mu=0. We present a
theory for this dynamics, to leading order in 1/\ln (\Lambda/ (k_B T)), where
\Lambda is a high energy cutoff. Although pairwise interactions between the
bosons are weak at low energy scales, the collective dynamics are strongly
coupled even when \ln (\Lambda/T) is large. We argue that the strong-coupling
effects can be isolated in an effective classical model, which is then solved
numerically. Applications to experiments on the gap-closing transition of spin
gap antiferromagnets in an applied field are presented.Comment: 9 pages, 10 figure
Relativistic Equilibrium Distribution by Relative Entropy Maximization
The equilibrium state of a relativistic gas has been calculated based on the
maximum entropy principle. Though the relativistic equilibrium state was long
believed to be the Juttner distribution, a number of papers have been published
in recent years proposing alternative equilibrium states. However, some of
these papers do not pay enough attention to the covariance of distribution
functions, resulting confusion in equilibrium states. Starting from a fully
covariant expression to avoid this confusion, it has been shown in the present
paper that the Juttner distribution is the maximum entropy state if we assume
the Lorentz symmetry.Comment: Six pages, no figure
SuperCYPsPred - a web server for the prediction of cytochrome activity
Cytochrome P450 enzymes (CYPs)-mediated drug metabolism influences drug pharmacokinetics and results in adverse outcomes in patients through drug-drug interactions (DDIs). Absorption, distribution, metabolism, excretion and toxicity (ADMET) issues are the leading causes for the failure of a drug in the clinical trials. As details on their metabolism are known for just half of the approved drugs, a tool for reliable prediction of CYPs specificity is needed. The SuperCYPsPred web server is currently focused on five major CYPs isoenzymes, which includes CYP1A2, CYP2C19, CYP2D6, CYP2C9 and CYP3A4 that are responsible for more than 80% of the metabolism of clinical drugs. The prediction models for classification of the CYPs inhibition are based on well-established machine learning methods. The models were validated both on cross-validation and external validation sets and achieved good performance. The web server takes a 2D chemical structure as input and reports the CYP inhibition profile of the chemical for 10 models using different molecular fingerprints, along with confidence scores, similar compounds, known CYPs information of drugs-published in literature, detailed interaction profile of individual cytochromes including a DDIs table and an overall CYPs prediction radar chart (http://insilico-cyp.charite.de/SuperCYPsPred/).The web server does not require log in or registration and is free to use
Derivatives of spin dynamics simulations
We report analytical equations for the derivatives of spin dynamics
simulations with respect to pulse sequence and spin system parameters. The
methods described are significantly faster, more accurate and more reliable
than the finite difference approximations typically employed. The resulting
derivatives may be used in fitting, optimization, performance evaluation and
stability analysis of spin dynamics simulations and experiments.
Keywords: NMR, EPR, simulation, analytical derivatives, optimal control, spin
chemistry, radical pair.Comment: Accepted by The Journal of Chemical Physic
Stationarity, soft ergodicity, and entropy in relativistic systems
Recent molecular dynamics simulations show that a dilute relativistic gas
equilibrates to a Juettner velocity distribution if ensemble velocities are
measured simultaneously in the observer frame. The analysis of relativistic
Brownian motion processes, on the other hand, implies that stationary
one-particle distributions can differ depending on the underlying
time-parameterizations. Using molecular dynamics simulations, we demonstrate
how this relativistic phenomenon can be understood within a deterministic model
system. We show that, depending on the time-parameterization, one can
distinguish different types of soft ergodicity on the level of the one-particle
distributions. Our analysis further reveals a close connection between time
parameters and entropy in special relativity. A combination of different
time-parameterizations can potentially be useful in simulations that combine
molecular dynamics algorithms with randomized particle creation, annihilation,
or decay processes.Comment: 4 page
The Simple Non-degenerate Relativistic Gas: Statistical Properties and Brownian Motion
This paper shows a novel calculation of the mean square displacement of a
classical Brownian particle in a relativistic thermal bath. The result is
compared with the expressions obtained by other authors. Also, the
thermodynamic properties of a non-degenerate simple relativistic gas are
reviewed in terms of a treatment performed in velocity space.Comment: 6 pages, 2 figure
Thermal equilibrium and statistical thermometers in special relativity
There is an intense debate in the recent literature about the correct
generalization of Maxwell's velocity distribution in special relativity. The
most frequently discussed candidate distributions include the Juettner function
as well as modifications thereof. Here, we report results from fully
relativistic one-dimensional (1D) molecular dynamics (MD) simulations that
resolve the ambiguity. The numerical evidence unequivocally favors the Juettner
distribution. Moreover, our simulations illustrate that the concept of 'thermal
equilibrium' extends naturally to special relativity only if a many-particle
system is spatially confined. They make evident that 'temperature' can be
statistically defined and measured in an observer frame independent way.Comment: version accepted for publication (5 pages), part of the introduction
modified, new figures, additional reference
mVOC: a database of microbial volatiles
Scents are well known to be emitted from flowers and animals. In nature, these volatiles are responsible for inter- and intra-organismic communication, e.g. attraction and defence. Consequently, they influence and improve the establishment of organisms and populations in ecological niches by acting as single compounds or in mixtures. Despite the known wealth of volatile organic compounds (VOCs) from species of the plant and animal kingdom, in the past, less attention has been focused on volatiles of microorganisms. Although fast and affordable sequencing methods facilitate the detection of microbial diseases, however, the analysis of signature or fingerprint volatiles will be faster and easier. Microbial VOCs (mVOCs) are presently used as marker to detect human diseases, food spoilage or moulds in houses. Furthermore, mVOCs exhibited antagonistic potential against pathogens in vitro, but their biological roles in the ecosystems remain to be investigated. Information on volatile emission from bacteria and fungi is presently scattered in the literature, and no public and up-to-date collection on mVOCs is available. To address this need, we have developed mVOC, a database available online at http://bioinformatics.charite.de/mvoc
Estimation of Mechanical Vibrations of the LHC Fast Magnetic Measurement System
Current installation of the Large Hadron Collider (LHC) particle accelerator at CERN has required the use of a harmonic coil magnetic measurement system to quantify the magnetic field harmonic quality of the superconducting, twin aperture LHC dipoles. Current and future needs for measuring fast changing magnetic fields necessitates the use of a rotating unit (RU) and associated electronics to drive this long shaft with increased speed and measurement bandwidth. Therefore, the Fast Magnetic Measurement Equipment (FAME) project has been launched to deliver such a system. A primary obstacle to achieving the goals of the FAME project is the possibility of amplifying mechanical vibrations due to increased speeds. This paper presents the methodology and results of an experimental investigation conducted to estimate mechanical vibrations of the long shaft within a cold-bore mounted anti-cryostat at various rotational speeds using magnetic measurements
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