BINA

We consider stochastic processes, piecewise constant in time, which can be viewed as a gapless sequences of statistically independent box functions of duration τ i and height v i. Lengths and heights of the boxes are deterministically coupled, whereas the areas τ i v i are iid random variables. These processes are closely related to the velocity process of space-time coupled Levy walks, but can more generally be viewed as a renewal processes, where the life times τ i are not simply drawn from one given distribution, but are determined via a deterministic law by the values v i of a relevant stochastic variable. Despite its simplicity, these processes can show anomalous diffusion, or, more general, anomalous behavior of its moments. The latter can be related either to invariant densities, which are non-normalizable, or, for other parameters, to certain scaling densities. We obtained exact results for these quantities …

SYNTHESIS OF ARGENTUM VANADATE'S OBTAINED BY ION-EXCHANGING WAY ON THE BASE OF SYNTHESIZED ELECTROCHEMICALLY V 2 O 5-X· YH 2 O, AND THEIR BEHAVIOR IN THE ELECTRODES FOR LITHIUM ACCUMULATOR

We propose an experimentally realizable method to demonstrate Lyapunov instability and to estimate ergodization time in chaotic many-particle systems by monitoring equilibrium noise of virtually any observable quantity before and after time reversal of dynamics (Loschmidt echo). In the quantum regime, the quantity of interest for the method is a counterpart of out-of-time-order correlators (OTOCs). The ergodization time is defined as the characteristic time required to extract the largest Lyapunov exponent from a system's dynamics. The proposal focuses specifically on a lattice of coupled Bose-Einstein condensates in the classical regime describable by the discrete Gross-Pitaevskii equation. We support our theoretical analysis by direct numerical simulations demonstrating that the largest Lyapunov exponent and the ergodization time can indeed be extracted from the Loschmidt echo routine.

Oil emulsion droplets in water have been observed to spontaneously deform into polyhedral shapes at temperatures where the surfactant interface freezes while the bulk oil and water remain liquid. The interface monolayer crystalizes into a hexagonal lattice, which is topologically constrained to accomodate a certain number of defects, namely disclinations. Additional defects, called dislocations, are also expected to be found in crystals with large number of particles. Dislocations are not only thermally induced but, more importantly, they are known to screen the large stresses around disclinations by forming chain-like structures at their vicinity. We address the problem of faceting droplets by studying the interplay between the interface geometry and the arragement of dislocations. We have found that the coupling between the distribution of crystal defects, surface curvature and entropy is key to understand the …

Adenosine to inosine (A-to-I) RNA editing is a co/post-transcriptional modification of double stranded RNA, catalysed by the adenosine deaminase acting on RNA (ADAR) family of enzymes, which results in recognition of inosine as guanosine by translational and splicing machinery causing potential recoding events in amino acid sequences. A-to-I editing is prominent within brain-specific transcripts and dysregulation of editing at several well-studied loci (e.g., Gria2, Htr2c) has been implicated in acute and chronic stress in rodents as well as neurological (e.g., Alzheimer’s) and psychopathological disorders such as schizophrenia and major depressive disorder. However, only a small fraction of recoding sites has been investigated within the brain following stress and our understanding of the role of RNA editing in transcriptome regulation following environmental stimuli remains poorly understood. Thus, we aimed …

Background: There are compelling evidence from animal models and retrospective clinical studies that early exposure to clinically relevant general anesthetic medications interferes with brain development and may lead to permanent cognitive impairments. 1 2 At least in immature rodents, exposure to either NMDA-type glutamate receptor antagonists or positive modulators of GABAA receptors can lead to increased apoptosis. Blockade of NMDA receptors by ketamine in the developing rodent brain causes excessive apoptosis. 2 Additionally, ketamine inhibits proliferation of neural stem cells and disturbs normal neurogenesis. 3 However, it is currently not clear whether similar exposures can similarly affect children and what are the mechanisms that mediate these effects. Neurosteroids such as allopregnanolone (ALLO) have anesthetic properties and have been shown to be neuroprotective. 4 Understanding their neuroprotective role in anesthetic induced injury may have major implications in decreasing anesthetic-induced brain damage or designing potentially less toxic anesthetic agents. 5Methods: In this project we studied the effects of ketamine on human neural stem cells, and neurons. We have generated immortalized human neural stem cells (NSCs), and neurons that maintain the phenotypes and functions of the original cells.Results: Using human neural cells in culture, we demonstrated that ketamine induced a dose-dependent decrease in the proliferation of NSCs and an increase in cell death of neurons (Figure). We also demonstrate that ALLO (1 μM) protected NSCs from the inhibitory effect of ketamine on cell proliferation. Moreover …

Although Pb Halide perovskites (HaPs) can be prepared as organic electronic materials, they resemble top-quality inorganic semiconductors, especially with respect to their low defect densities, as derived from optical and electronic transport studies. Among causes for such low defect densities were ‘defect-tolerance’ (proposed) and ‘self-healing’ (experimentally identified). We show that HaPs are likely an example of a class of materials that cannot support static bulk defect densities significantly above thermodynamically-dictated densities. The reasons are (a) the free energy to form HaPs (from binary halides) is less than the formation energies of (static) defects in them and (b) the small kinetic stabilization of such defects. We summarize the evidence for such a situation and conclude that higher defect densities in polycrystalline films likely result from the (expected) smaller defect formation energy at surfaces and …

We present a so-called “split-well direct-phonon” active region design for terahertz quantum cascade lasers (THz-QCLs). Lasers based on this scheme profit from both elimination of high-lying parasitic bound states and resonant-depopulation of the lower laser level. Negative differential resistance is observed at room temperature, which indicates that each module behaves as a clean 3-level system. We further use this design to investigate the impact of temperature on the dephasing time of GaAs/AlGaAs THz-QCLs.

Many catalyst materials have been tried to synthesize ultra-long carbon nanotubes (CNTs) by extending catalyst lifetime and delaying growth termination. We propose a time-controlled, variable composition iron–molybdenum catalyst system, where the diffusion of molybdenum (as a thin layer reservoir) is mediated by the alumina underlayer, to reach and to slowly alloy with the Fe catalyst on the surface during the thermal process. This technique enhanced both the catalytic activity and the catalytic lifetime to grow CNT carpets with heights up 5 mm, compared to a maximum of approximately 1.5 mm for a regular sample (without Mo reservoir). Moreover, the CNT height increased with the thickness of the Mo thin layer reservoir for thicknesses from 10 nm to 30 nm. We discuss this new growth mechanism using high resolution transmission microscopy (HRTEM) images of cross-section lamellas and Rutherford Back …

Nonfunctionalized carbon nanotubes featuring length over than 500 μm, were mixed with an amino-functionalized sol-gel precursor and a highly volatile solvent in order to obtain a well-dispersed solution. Finally, a thickener was added to the nanotubes dispersion thus obtaining a viscous paste, which was deposited on cotton fabrics through knife-over-roll technique thus achieving a surface coating with high electrical conductivity. The as-prepared conductive cotton fabrics were characterized by different chemical-physical techniques and showed a sheet resistance of about 9.5• 102 Ω/sq. Developed conductive fabrics can find applications as conductive material or wearable sensors.

The synthesis of chiral nanoporous carbons based on chiral ionic liquids (CILs) of amino acids as precursors is described. Such unique precursors for the carbonization of CILs yield chiral carbonaceous materials with high surface area (≈620 m2 g−1). The enantioselectivities of the porous carbons are examined by advanced techniques such as selective adsorption of enantiomers using cyclic voltammetry, isothermal titration calorimetry, and mass spectrometry. These techniques demonstrate the chiral nature and high enantioselectivity of the chiral carbon materials. Overall, we believe that the novel approach presented here can contribute significantly to the development of new chiral carbon materials that will find important applications in chiral chemistry, such as in chiral catalysis and separation and in chiral sensors. From a scientific point of view, the approach and results reported here can significantly deepen …

Optical trapping is a powerful optical manipulation technique for controlling various mesoscopic systems that allows formation of tailor-made polymeric micro-sized colloids by directed coalescence of nucleation sites. However, control over the size of a single colloid requires constant monitoring of the growth process and deactivation of the optical trap once it reaches the required dimensions. Moreover, producing more than one colloid requires moving the sample to a pristine location where the process must be repeated. Here, we present a novel method for continuous control over formation of polydimethylsiloxane colloids based on directed coalescence induced by optical traps under flow inside microfluidic channels. Once the drag force on a growing colloid exceeds the trapping force, it leaves the optical trap, and a new colloid starts to form at the same location. We demonstrate repeatability of the process and …

Micro-patterning of a metal organic framework (MOF) from a solution of precursors is achieved by local laser heating. Nano-sized MOFs are formed, followed by rapid assembly due to convective flows around a heat-induced micro-bubble. This laser-induced bottom-up technique is the first to suggest simultaneous synthesis and micro-patterning of MOFs, alleviating the need for pre-preparation and stabilization.

Li-rich nickel cobalt manganese (NCM) oxides are among the most promising cathode materials for lithium-ion batteries owing to their high specific charges and operating voltages. However, their crystal structures are unstable upon prolonged cycling, leading to a collapse of their electrochemical performance. In this study, we investigated Fe doping of Li-rich NCM materials and explored various Li/Fe ratios. Compared with the reference Li-rich NCM material, the Li1.16(Ni0.18Co0.10Mn0.52Fe0.02)O2 composition exhibited a higher specific charge, potential drop mitigation at fast cycling rates, and an enhanced rate capability. At a rate of 4C, this composition exhibited a specific charge of 150 mA h g−1, which was as much as 50% higher than that of the reference (100 mA h g−1). Neutron and X-ray diffraction data for compounds with different Fe doping concentrations indicated that the crystallographic structure was …