Moscow Institute of Physics and Technology

About: Moscow Institute of Physics and Technology is a education organization based out in Dolgoprudnyy, Russia. It is known for research contribution in the topics: Laser & Plasma. The organization has 8594 authors who have published 16968 publications receiving 246551 citations. The organization is also known as: MIPT & Moscow Institute of Physics and Technology (State University).

Temperature dependence of shear viscosity of SU(3)-gluodynamics within lattice simulation

Abstract: In this paper we study the SU(3)-gluodynamics shear viscosity temperature dependence on the lattice. To do so, we measure the correlation functions of the energy-momentum tensor in the range of temperatures T /T c ∈ [0.9, 1.5]. To extract the shear viscosity we used two approaches. The first one is to fit the lattice data with a physically motivated ansatz for the spectral function with unknown parameters and then determine the shear viscosity. The second approach is to apply the Backus-Gilbert method allowing to extract the shear viscosity from the lattice data nonparametrically. The results obtained within both approaches agree with each other. Our results allow us to conclude that within the range T /T c ∈ [0.9, 1.5] the SU(3)-gluodynamics reveals the properties of a strongly interacting system, which cannot be described perturbatively, and has the ratio η/s close to the value 1/4π of the N = 4 Supersymmetric Yang-Mills theory.

PREDDIMER: a web server for prediction of transmembrane helical dimers

Abstract: Summary: Here we present PREDDIMER, a web tool for prediction of dimer structure of transmembrane (TM) helices. PREDDIMER allows (i) reconstruction of a number of dimer structures for given sequence(s) of TM protein fragments, (ii) ranking and filtering of predicted structures according to respective values of a scoring function, (iii) visualization of predicted 3D dimer structures and (iv) visualization of surface hydrophobicity of TM helices and their contacting (interface) regions represented as 2D maps. Results: We implemented online the original PREDDIMER algorithm and benchmarked the server on 11 TM sequences, whose 3D dimer conformations were obtained previously by nuclear magnetic resonance spectroscopy. In the most of tested cases backbone rootmean-square deviations of closest predicted conformations from the experimental reference are below 3 A ˚ . A randomization test displays good anticorrelation (0.82) between values of the scoring function and statistical significance of the prediction ‘by chance’. Going beyond a single dimer conformation, our web tool predicts an ensemble of possible conformations, which may be useful for explanation of a functioning of bitopic membrane proteins, e.g. receptor tyrosine kinases.

A mycobacterial ABC transporter mediates the uptake of hydrophilic compounds.

Abstract: Mycobacterium tuberculosis (Mtb) is an obligate human pathogen and the causative agent of tuberculosis1–3. Although Mtb can synthesize vitamin B12 (cobalamin) de novo, uptake of cobalamin has been linked to pathogenesis of tuberculosis2. Mtb does not encode any characterized cobalamin transporter4–6; however, the gene rv1819c was found to be essential for uptake of cobalamin1. This result is difficult to reconcile with the original annotation of Rv1819c as a protein implicated in the transport of antimicrobial peptides such as bleomycin7. In addition, uptake of cobalamin seems inconsistent with the amino acid sequence, which suggests that Rv1819c has a bacterial ATP-binding cassette (ABC)-exporter fold1. Here, we present structures of Rv1819c, which reveal that the protein indeed contains the ABC-exporter fold, as well as a large water-filled cavity of about 7,700 A3, which enables the protein to transport the unrelated hydrophilic compounds bleomycin and cobalamin. On the basis of these structures, we propose that Rv1819c is a multi-solute transporter for hydrophilic molecules, analogous to the multidrug exporters of the ABC transporter family, which pump out structurally diverse hydrophobic compounds from cells8–11. Analysis of cryo-electron microscopy structures of the Mycobacterium tuberculosis ABC transporter Rv1819c suggests that it is a multi-solute transporter for hydrophilic molecules.

Search for top quark decays t → qH with H → γγ using the ATLAS detector

Abstract: A search is performed for flavour-changing neutral currents in the decay of a top quark to an up-type (c, u) quark and a Higgs boson, where the Higgs boson decays to two photons. The proton-proton collision data set used corresponds to 4.7 fb-1 at √ = 7TeV and 20.3fb-1 at √ = 8TeV collected by the ATLAS experiment at the LHC. Top quark pair events are searched for in which one top quark decays to qH and the other decays to bW. Both the hadronic and the leptonic decay modes of the W boson are used. No significant signal is observed and an upper limit is set on the t → qH branching ratio of 0.79 at the 95% confidence level. The corresponding limit on the tqH coupling combination λtcH 2 + λtuH 2 is 0.17.