Connection between slow and fast dynamics of molecular liquids around the glass transition

The mean-square displacement (MSD) was measured by neutron scattering at various temperatures and pressures for a number of molecular glass-forming liquids. The MSD is invariant along the glass-transition line at the pressure studied, thus establishing an ``intrinsic'' Lindemann criterion for any given liquid. A one-to-one connection between the MSD's temperature dependence and the liquid's fragility is found when the MSD is evaluated on a time scale of approximately 4 nanoseconds, but does not hold when the MSD is evaluated at shorter times. The findings are discussed in terms of the elastic model and the role of relaxations, and the correlations between slow and fast dynamics are addressed.Comment: accepted by Phys Rev E (2010

Dried chicory root (Cichorium intybus L.) as a natural fructan source in rabbit diet: effects on growth performance, digestion and caecal and carcass traits

[EN] Three experimental diets were formulated including (per kg) 100 g oats (control diet), 50 g chicory root (Chicory 5 diet) or 100 g chicory root (Chicory 10 diet) at the expense of oats. The diets differed with respect to starch and fructan contents. In the performance trial, 120 Hyplus rabbits were randomly allocated to three groups (two rabbits per cage) and fed one of the three experimental diets between 31 and 73 days of age. At the end of the trial period, 20 rabbits per treatment were slaughtered and used for evaluation of carcass traits. In addition, the coefficients of total tract apparent digestibility (CTTAD) of the diets and caecal traits were determined from 45 to 49 days of age in 10 rabbits per treatment. The diets did not differ significantly in terms of weight gain, feed intake, feed conversion ratio, health status or carcass traits of rabbits. The CTTADs of crude protein (P=0.041) and ether extract (P=0.006) were lower in rabbits fed the Chicory 10 diet than in rabbits fed the control diet. The CTTAD of starch (P<0.001) was lower, whereas that of fructans (P<0.001) higher, in rabbits fed the diets based on chicory root. The caecum weight (P=0.037), the weight of its contents (P=0.025) and the lactic acid (P=0.028) concentration were higher in rabbits fed the Chicory 10 diet than in control rabbits. On the contrary, rabbits fed with the chicory diets showed lower caecal pH (P=0.048) than rabbits fed the control diet. There was a tendency towards a lower caecal dry matter content and higher total VFA concentration in rabbits fed the chicory diets. It may be concluded that chicory root can serve as a natural source of inulin-type fructans in rabbit feed. Diet supplementation with 10% dried chicory root beneficially affected the caecal fermentative activity in the rabbits, without significant reductions in the nutritive value of the diet, growth performance or carcass quality.Financial support for this study was provided by the institutional research project MZE 0002701404Volek, Z.; Marounek, M. (2011). Dried chicory root (Cichorium intybus L.) as a natural fructan source in rabbit diet: effects on growth performance, digestion and caecal and carcass traits. World Rabbit Science. 19(3):143-150. https://doi.org/10.4995/wrs.2011.850SWORD14315019

The origin of the hot metal-poor gas in NGC1291: Testing the hypothesis of gas dynamics as the cause of the gas heating

In this paper we test the idea that the low-metallicity hot gas in the centre of NGC 1291 is heated via a dynamical process. In this scenario, the gas from the outer gas-rich ring loses energy through bar-driven shocks and falls to the centre. Heating of the gas to X-ray temperatures comes from the high velocity that it reaches ($\approx$ 700 \kms) as it falls to the bottom of the potential well. This would explain why the stellar metallicity in the bulge region is around solar while the hot gas metallicity is around 0.1 solar. We carried out an observational test to check this hypothesis by measuring the metallicity of HII regions in the outer ring to check whether they matched the hot gas metallicity. For this purpose we obtained medium resolution long slit spectroscopy with FORS1 on the ESO VLT at Paranal and obtained the metallicities using emission line ratio diagnostics. The obtained metallicities are compatible with the bulge stellar metallicities but very different from the hot-gas metallicity. However, when comparing the different time-scales, the gas in the ring had time enough to get enriched through stellar processes, therefore we cannot rule out the dynamical mechanism as the heating process of the gas. However, the blue colours of the outer ring and the dust structures in the bar region could suggest that the origin of the X-ray hot gas is due to the infall of material from further out.Comment: 6 pages, 6 figures. A&A accepte

On the correlation between fragility and stretching in glassforming liquids

We study the pressure and temperature dependences of the dielectric relaxation of two molecular glassforming liquids, dibutyl phtalate and m-toluidine. We focus on two characteristics of the slowing down of relaxation, the fragility associated with the temperature dependence and the stretching characterizing the relaxation function. We combine our data with data from the literature to revisit the proposed correlation between these two quantities. We do this in light of constraints that we suggest to put on the search for empirical correlations among properties of glassformers. In particular, argue that a meaningful correlation is to be looked for between stretching and isochoric fragility, as both seem to be constant under isochronic conditions and thereby reflect the intrinsic effect of temperature

Pharmacologic Therapies to Prevent Relapse of Acute Myeloid Leukemia After Allogeneic Hematopoietic Stem Cell Transplantation

Relapse is the main cause of mortality in patients with acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Adverse cytogenetic or molecular risk factors, as well as refractory disease or persistent measurable residual disease (MRD) at the time of transplantation are associated with an increased risk of recurrence. Salvage therapy for AML relapse after allo-HSCT is often limited to chemotherapy, donor lymphocyte infusions and/or second transplants and is rarely successful. Effective post-transplant preventive intervention in high risk AML may be crucial. The most frequent and promising approach is the use of post-transplant maintenance with hypomethylating agents or with FLT3 tyrosine kinase inhibitors when the target is present. Moreover, IDH1/IDH2 inhibitors and BCL-2 inhibitors in combination with other strategies are promising approaches in the maintenance setting. Here we summarize the current knowledge about the preemptive and prophylactic use of pharmacologic agents after allo-HSCT to prevent relapse of AML

Selective photocatalytic CO2_2 reduction in water through anchoring of a molecular Ni catalyst on CdS nanocrystals

Photocatalytic conversion of CO$_2$ into carbonaceous feedstock chemicals is a promising strategy to mitigate greenhouse gas emissions and simultaneously store solar energy in chemical form. Photocatalysts for this transformation are typically based on precious metals and operate in nonaqueous solvents to suppress competing H$_2$ generation. In this work, we demonstrate selective visible-light-driven CO$_2$ reduction in water using a synthetic photocatalyst system that is entirely free of precious metals. We present a series of self-assembled nickel terpyridine complexes as electrocatalysts for the reduction of CO$_2$ to CO in organic media. Immobilization on CdS quantum dots allows these catalysts to be active in purely aqueous solution and photocatalytically reduce CO$_2$ with >90% selectivity under UV-filtered simulated solar light irradiation (AM 1.5G, 100 mW cm$^{–2}$, λ > 400 nm, pH 6.7, 25 °C). Correlation between catalyst immobilization efficiency and product selectivity shows that anchoring the molecular catalyst on the semiconductor surface is key in controlling the selectivity for CO$_2$ reduction over H$_2$ evolution in aqueous solution.Christian Doppler Research Association, OMV group, Isaac Newton Trust, the German Research Foundation, the World Premier International Research Center Initiative, MEXT, Japa