Regulatory feedback from nascent RNA to chromatin and transcription

Transcription and chromatin function are regulated by proteins that bind to DNA, nucleosomes or RNA polymerase II, with specific non-coding RNAs (ncRNAs) functioning to modulate their recruitment or activity. Unlike ncRNAs, nascent pre-mRNA was considered to be primarily a passive player in these processes. In this Opinion article, we describe recently identified interactions between nascent pre-mRNAs and regulatory proteins, highlight commonalities between the functions of nascent pre-mRNA and nascent ncRNA, and propose that both types of RNA have an active role in transcription and chromatin regulation

Microscopic glass-transition in Ni-based metallic glass-forming melts

Quasielastic neutron scattering (QENS) has been used to investigate microscopic dynamics in the glass-forming Ni80P20, Pd40Ni40P20 and Pd43Ni10Cu27P20 melts. These melts are characterized by a high-packing fraction that is similar at their liquidus temperatures. Increasing the number of components in these melts increases the viscosity at their liquidus temperature. However, the fragility of these melts did not show a composition dependence. Atomic dynamics in these liquids agree well with mode-coupling theory (MCT) predictions. From the MCT analysis of the QENS data the critical packing fractions for the microscopic glass-transition (ϕc) were obtained. The values obtained for ϕc are well within the MCT theoretical predictions for hard-sphere liquids

Diffusion and adsorption of methane confined in nano-porous carbon aerogel: A combined quasi-elastic and small-angle neutron scattering study

The diffusion of methane confined in nano-porous carbon aerogel with the average pore size 48 angstrom and porosity similar to 60% was investigated as a function of pressure at T = 298 K using quasi-elastic neutron scattering (QENS). The diffusivity of methane shows a clear effect of confinement: it is about two orders of magnitude lower than in bulk at the same thermodynamic conditions and is close to the diffusivity of liquid methane at 100 K (i.e. similar to 90 K below the liquid-gas critical temperature T-c approximate to 191 K). The diffusion coefficient (D) of methane initially increases with pressure by a factor of similar to 2.5 from 3.47 +/- 0.41 x 10(-10) m(2) s(-1) at 0.482 MPa to D = 8.55 +/- 0.33 x 10(-10) m(2) s(-1) at 2.75 MPa and starts to decrease at higher pressures. An explanation of the observed non-monotonic behavior of the diffusivity in the confined fluid is based on the results of small-angle neutron scattering experiments of the phase behavior of methane in a similar carbon aerogel sample. The initial increase of the diffusion coefficient with pressure is explained as due to progressive filling of bigger pores in which molecular mobility in the internal pore volume is less affected by the sluggish liquid-like molecular mobility in the adsorbed phase. Subsequent decrease of D, is associated with the effect of intermolecular collisions, which result in a lower total molecular mobility with pressure, as in the bulk state. The results are compared with the available QENS data on the methane diffusivity in zeolites, metal organic frameworks, and porous silica as well as with the molecular dynamics simulations of methane in nano-porous carbons and silica zeolites. (C) 2010 Elsevier Inc. All rights reserved

Situational and Personal Factors Influencing Hospitality Employee Engagement in Value Co-creation

This study explores the situational and personal factors affecting hospitality employees\u27 engagement in the co-creation of value. The concept of value co-creation emerged from the general co-creation literature, and little research has assessed how situational and personal factors enhance our understanding of value creation. To explore these underlying factors, a qualitative study involving in-depth and focus group interviews was conducted at three luxury hotels in Hong Kong and Macao. The research findings indicate five situational factors and five personal factors impact cocreated value for hotel guests in the luxury sector. Insights are provided into the potential use of these factors to better manage employee engagement and the customer experience to facilitate value co-creation. The implications of the study and directions for future research are discussed

Quasielastic neutron scattering study of water confined in carbon nanopores

Microscopic dynamics of water confined in nanometer and sub-nanometer pores of carbide-derived carbon (CDC) were investigated using quasielastic neutron scattering (QENS). The temperature dependence of the average relaxation time, ⟨τ⟩, exhibits super-Arrhenius behavior that could be described by Vogel-Fulcher-Tammann (VFT) law in the range from 250 K to 190 K; below this temperature, ⟨τ⟩ follows Arrhenius temperature dependence. The temperature of the dynamic crossover between the two regimes in water confined in the CDC pores is similar to that observed for water in hydrophobic confinement of the larger size, such as 14 Å ordered mesoporous carbon (CMK) and 16 Å double-wall carbon nanotubes. Thus, the dynamical behavior of water remains qualitatively unchanged even in the very small hydrophobic pores

Fast diffusion in a room temperature ionic liquid confined in mesoporous carbon

We report a quasielastic neutron scattering study in the temperature range of 290 to 350 K of a room temperature ionic liquid, [bmim+][Tf2N−], in the bulk form and confined in the 8.8±2.1 nm diameter pores of a mesoporous carbon matrix. In both bulk and confined liquids, our measurements, which are sensitive to the dynamics of the hydrogen-bearing cations, detect two distinct relaxation processes related to the diffusion of the cations. We have found that the cations that do not become immobilized near the pore walls exhibit an enhanced rather than suppressed diffusivity compared to the cation diffusivity in bulk liquid. Our results provide first experimental observation of molecular diffusion in a room temperature ionic liquid in confinement which is faster than diffusion in the bulk liquid

An unusual slowdown of fast diffusion in a room temperature ionic liquid confined in mesoporous carbon

Using quasielastic neutron scattering in the temperature range from 290 to 350 K, we show that the diffusive motions in a room temperature ionic liquid [H2NC(dma)2][BETI] become faster for a fraction of cations when the liquid is confined in a mesoporous carbon. This applies to both the localized and long-range translational diffusive motions of the highly mobile cations, although the former exhibit an unusual trend of slowing-down as the temperature is increased, until the localized diffusivity is reduced to the bulk ionic liquid value at a temperature of 350 K