Superconductivity enhanced conductance fluctuations in few layer graphene nanoribbons

We investigate the mesoscopic disorder induced rms conductance variance $\delta G$ in a few layer graphene nanoribbon (FGNR) contacted by two superconducting (S) Ti/Al contacts. By sweeping the back-gate voltage, we observe pronounced conductance fluctuations superimposed on a linear background of the two terminal conductance G. The linear gate-voltage induced response can be modeled by a set of inter-layer and intra-layer capacitances. $\delta G$ depends on temperature T and source-drain voltage $V_{sd}$. $\delta G$ increases with decreasing T and $|V_{sd}|$. When lowering $|V_{sd}|$, a pronounced cross-over at a voltage corresponding to the superconducting energy gap $\Delta$ is observed. For |V_{sd}|\ltequiv \Delta the fluctuations are markedly enhanced. Expressed in the conductance variance $G_{GS}$ of one graphene-superconducutor (G-S) interface, values of 0.58 e^2/h are obtained at the base temperature of 230 mK. The conductance variance in the sub-gap region are larger by up to a factor of 1.4-1.8 compared to the normal state. The observed strong enhancement is due to phase coherent charge transfer caused by Andreev reflection at the nanoribbon-superconductor interface.Comment: 15 pages, 5 figure

Health lipid indices of dry fermented sausages made of pork meat

This research presents the results of a comparison assessment of the cholesterol content, fatty acid profile, and atherogenic (IA) and thrombogenic (IT) health lipid parameters of four dry fermented sausages produced from Mangalitsa and Swedish Landrace pork meat. The highest cholesterol level was found in Sremska sausage prepared from Landrace meat (64.92 mg/100g). Polyunsaturated fatty acid (PUFA) levels were considerably greater in Landrace meat sausages than in other kinds. The main cause of these variations was a higher overall n-6 PUFA concentration. The sausages made from Mangalitsa meat had the highest levels of monounsaturated fatty acid (MUFA) and unsaturated fatty acid (USFA). The highest saturated fatty acid (SFA) level was found in sausages prepared from Landrace meat. Fermented sausages made from Mangalitsa pork meat show better health lipid indices, atherogenic (IA), thrombogenic (IT), and PUFA/SFA ratios

Quantum Hall Effects in Graphene-Based Two-Dimensional Electron Systems

In this article we review the quantum Hall physics of graphene based two-dimensional electron systems, with a special focus on recent experimental and theoretical developments. We explain why graphene and bilayer graphene can be viewed respectively as J=1 and J=2 chiral two-dimensional electron gases (C2DEGs), and why this property frames their quantum Hall physics. The current status of experimental and theoretical work on the role of electron-electron interactions is reviewed at length with an emphasis on unresolved issues in the field, including assessing the role of disorder in current experimental results. Special attention is given to the interesting low magnetic field limit and to the relationship between quantum Hall effects and the spontaneous anomalous Hall effects that might occur in bilayer graphene systems in the absence of a magnetic field

A Major Determinant of Cyclophilin Dependence and Cyclosporine Susceptibility of Hepatitis C Virus Identified by a Genetic Approach

Since the advent of genome-wide small interfering RNA screening, large numbers of cellular cofactors important for viral infection have been discovered at a rapid pace, but the viral targets and the mechanism of action for many of these cofactors remain undefined. One such cofactor is cyclophilin A (CyPA), upon which hepatitis C virus (HCV) replication critically depends. Here we report a new genetic selection scheme that identified a major viral determinant of HCV's dependence on CyPA and susceptibility to cyclosporine A. We selected mutant viruses that were able to infect CyPA-knockdown cells which were refractory to infection by wild-type HCV produced in cell culture. Five independent selections revealed related mutations in a single dipeptide motif (D316 and Y317) located in a proline-rich region of NS5A domain II, which has been implicated in CyPA binding. Engineering the mutations into wild-type HCV fully recapitulated the CyPA-independent and CsA-resistant phenotype and four putative proline substrates of CyPA were mapped to the vicinity of the DY motif. Circular dichroism analysis of wild-type and mutant NS5A peptides indicated that the D316E/Y317N mutations (DEYN) induced a conformational change at a major CyPA-binding site. Furthermore, nuclear magnetic resonance experiments suggested that NS5A with DEYN mutations adopts a more extended, functional conformation in the putative CyPA substrate site in domain II. Finally, the importance of this major CsA-sensitivity determinant was confirmed in additional genotypes (GT) other than GT 2a. This study describes a new genetic approach to identifying viral targets of cellular cofactors and identifies a major regulator of HCV's susceptibility to CsA and its derivatives that are currently in clinical trials

An NMR strategy for fragment-based ligand screening utilizing a paramagnetic lanthanide probe

A nuclear magnetic resonance-based ligand screening strategy utilizing a paramagnetic lanthanide probe is presented. By fixing a paramagnetic lanthanide ion to a target protein, a pseudo-contact shift (PCS) and a paramagnetic relaxation enhancement (PRE) can be observed for both the target protein and its bound ligand. Based on PRE and PCS information, the bound ligand is then screened from the compound library and the structure of the ligand–protein complex is determined. PRE is an isotropic paramagnetic effect observed within 30 Å from the lanthanide ion, and is utilized for the ligand screening in the present study. PCS is an anisotropic paramagnetic effect providing long-range (~40 Å) distance and angular information on the observed nuclei relative to the paramagnetic lanthanide ion, and utilized for the structure determination of the ligand–protein complex. Since a two-point anchored lanthanide-binding peptide tag is utilized for fixing the lanthanide ion to the target protein, this screening method can be generally applied to non-metal-binding proteins. The usefulness of this strategy was demonstrated in the case of the growth factor receptor-bound protein 2 (Grb2) Src homology 2 (SH2) domain and its low- and high-affinity ligands

Fatty acid profile and cholesterol content of M. longissimus of free-range and conventionally reared Mangalitsa pigs

This study investigated the effects of different feeding systems (free-range versus conventional rearing) on carcass characteristics, chemical composition, fatty acid profile and cholesterol content of the musculus longissimus lumborum et thoracis (MLLT) of Mangalitsa pigs. Depending on the rearing system employed and live weight observed, we found statistically significant differences in the weight of the warm and cold Mangalitsa carcasses. Furthermore, we observed that conventionally reared Mangalitsa pigs weighed more. Measurements showed that the free-range-fed pigs had a lower total backfat thickness in comparison with the group reared in the conventional system, but that these differences were not significant. Outdoor rearing of the pigs led to higher protein, ash and water contents, and to a decrease in total fat content and pH values of the MLLT. The choice of rearing system did not significantly affect the cholesterol content. The fat of the free-range pigs had a higher concentration of n-3 and n-6 polyunsaturated fatty acids (PUFA), while the n-6/n-3 PUFA ratio was significantly lower than in conventionally reared pigs. The proportion of PUFA/SFA (saturated fatty acids) was not significantly different, whereas the proportion of monounsaturated fatty acids (MUFA/SFA) was significantly lower in the free-range group. It is concluded that the rearing system affects the carcass properties and chemical characteristics of Mangalitsa meat; it does so in particular by improving the fatty acid composition in free-range pigs.Keywords: Rearing system, pork quality, indigenous breed, health foo