First results on K/π, p/π and K/p fluctuations are obtained with the ALICE detector at the CERN LHC as a function of centrality in Pb--Pb collisions at sNN−−−√=2.76 TeV. The observable νdyn, which is ...defined in terms of the moments of particle multiplicity distributions, is used to quantify the magnitude of dynamical fluctuations of relative particle yields and also provides insight into the correlation between particle pairs. This study is based on a novel experimental technique, called the Identity Method, which allows one to measure the moments of multiplicity distributions in case of incomplete particle identification. The results for p/π show a change of sign in νdyn from positive to negative towards more peripheral collisions. For central collisions, the results follow the smooth trend of the data at lower energies and νdyn exhibits a change in sign for p/π and K/p.
The MBIR multipurpose, sodium-cooled, fast reactor designed by NIKIET is supposed to be started up in 2019 on the grounds of NIIAR. The reactor will be used to study and test new types of nuclear ...fuel, coolant, and building materials. This article reviews the subcriticality monitoring system of the MBIR reactor facility. The purpose, composition, and mathematical software of the subcriticality monitoring system are described.
Proteins exist as a dynamic ensemble of interconverting substates, which defines their conformational energy landscapes. Recent work has indicated that mutations that shift the balance between ...conformational substates (CSs) are one of the main mechanisms by which proteins evolve new functions. In the present study, we probe this assertion by examining phenotypic protein adaptation to extreme conditions, using the allosteric tetrameric lactate dehydrogenase (LDH) from the hyperthermophilic bacterium Thermus thermophilus (Tt) as a model enzyme. In the presence of fructose 1, 6 bis-phosphate (FBP), allosteric LDHs catalyze the conversion of pyruvate to lactate with concomitant oxidation of nicotinamide adenine dinucleotide, reduced form (NADH). The catalysis involves a structural transition between a low-affinity inactive "T-state" and a high-affinity active "R-state" with bound FBP. During this structural transition, two important residues undergo changes in their side chain conformations. These are R171 and H188, which are involved in substrate and FBP binding, respectively. We designed two mutants of Tt-LDH with one ("1-Mut") and five ("5-Mut") mutations distant from the active site and characterized their catalytic, dynamical, and structural properties. In 1-Mut Tt-LDH, without FBP, the K(m)(Pyr) is reduced compared with that of the wild type, which is consistent with a complete shifting of the CS equilibrium of H188 to that observed in the R-state. By contrast, the CS populations of R171, k(cat) and protein stability are little changed. In 5-Mut Tt-LDH, without FBP, K(m)(Pyr) approaches the values it has with FBP and becomes almost temperature independent, k(cat) increases substantially, and the CS populations of R171 shift toward those of the R-state. These changes are accompanied by a decrease in protein stability at higher temperature, which is consistent with an increased flexibility at lower temperature. Together, these results show that the thermal properties of an enzyme can be strongly modified by only a few or even a single mutation, which serve to alter the equilibrium and, hence, the relative populations of functionally important native-state CSs, without changing the nature of the CSs themselves. They also provide insights into the types of mutational pathways by which protein adaptation to temperature is achieved.
The production of the charm-strange baryon Ξc0 is measured for the first time at the LHC via its semileptonic decay into eΞ−+νe in pp collisions at s=7 TeV with the ALICE detector. The transverse ...momentum (pT) differential cross section multiplied by the branching ratio is presented in the interval 1<pT<8 GeV/c at mid-rapidity, |y|<0.5. The transverse momentum dependence of the Ξc0 baryon production relative to the D0 meson production is compared to predictions of event generators with various tunes of the hadronisation mechanism, which are found to underestimate the measured cross-section ratio.
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The formation of plasma on the surface of a current-carrying electrode of a high-current facility when a current flows through it with a linear density of up to 4 MA/cm and is coated with lead foil ...or ceramic is studied. The propagation velocity of a dense plasma from a stainless steel electrode is 2–10 km/s, and when the electrode is coated with lead, it is 1–6 km/s. In these experiments, there is no load typical for such facilities—a source of intense X-ray radiation. The plasma propagation from ceramic-coated electrodes starts 200 ns later than that for metal electrodes.
Three different precipitating agents (NaOH,
NH
4
(
H
)
CO
3
and
CO
(
NH
2
)
2
) have been applied for the hydrothermal synthesis of ZnO powder materials, aiming at obtaining various types of porosity ...and surface species on ZnO. The synthesis procedures were carried out in the presence and in the absence of tri-block copolymer Pluronic (P123, EO20PO70EO20). These materials were characterized by powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM)–energy-dispersive X-ray spectroscopy (EDX), BET method and TG–differential thermal analysis (DTA) method, and their photocatalytic activities were tested in the removal azo dye Reactive Black 5 (RB5). The urea precipitant yields spongy-like surface forms and the greatest share of mesopores. It has the highest specific surface area, highest degree of crystallinity of wurtzite ZnO phase and largest content of surface OH groups in comparison with the other two precipitants. The zinc hydroxycarbonate intermediate phase is missing in the case of NaOH as precipitating agent; therefore, it manifests poorer textural characteristics. The morphology of P123-modified sample is different and consists of needle-shaped particles. The urea-precipitated samples display superior performance in the photocatalytic oxidation reaction, compared with the other precipitated samples. The other two precipitating agents are inferior in regard to their photocatalytic activity due to greater share of micropores (not well-illuminated inner surface) and different surface morphologies.
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Two novel aromatic thiophene-containing annulated compounds, viz. 2-methoxybnaphtho2,1-dthiophene and 1,3-dimethoxybnaphtho2,1-dthiophene, were synthesized via the Mallory-type ...photocyclization. Their optical, redox and photophysical properties have been studied along with phosphorescence spectra and lifetimes at 77 K. The first compound exhibited much higher charge mobility in thin films than the second one suggesting the former being prospective for molecular electronics applications
The structure of a new mononuclear nickel(II) complex with bis-azomethine Ni(H
2
L)
+
· CH
3
COO
–
· H
2
O, resulting from condensation of 1,3-diaminopropan-2-ol with 2-amino-3-formylpyridine (H
3
...L), was studied by X-ray diffraction (CIF files CCDC nos. 1562927, 1562928). Apart from the mononuclear complex, the reaction gave a minor amount of the trinuclear metal chelate Ni
3
L'(H
2
O)
2
+
· (CH
3
COO)
–
· CH
3
OH · H
2
O, where L' is N
5
O
2
-donor ligand containing two 3-(((2-aminopyridin-2-yl)methylene)amino)-1-aminopropan-2-ol moieties linked by a 2-aminopyridine-3-methylene group.
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