Electric-Field-Tunable Edge Transport in Bernal-Stacked Trilayer Graphene

This Letter presents a nonlocal study on the electric-field-tunable edge transport in h-BN-encapsulated dual-gated Bernal-stacked (ABA) trilayer graphene across various displacement fields (D) and temperatures (T). Our measurements revealed that the nonlocal resistance (R_{NL}) surpassed the expected classical Ohmic contribution by a factor of at least 2 orders of magnitude. Through scaling analysis, we found that the nonlocal resistance scales linearly with the local resistance (R_{L}) only when the D exceeds a critical value of ∼0.2  V/nm. Additionally, we observed that the scaling exponent remains constant at unity for temperatures below the bulk-band gap energy threshold (T<25  K). Further, the value of R_{NL} decreases in a linear fashion as the channel length (L) increases. These experimental findings provide evidence for edge-mediated charge transport in ABA trilayer graphene under the influence of a finite displacement field. Furthermore, our theoretical calculations support these results by demonstrating the emergence of dispersive edge modes within the bulk-band gap energy range when a sufficient displacement field is applied.

One-dimensional spin-orbit coupled Dirac system with extendeds-wave superconductivity: Majorana modes and Josephson effects

Motivated by the spin-momentum locking of electrons at the boundaries of certain topological insulators, we study a one-dimensional system of spin-orbit coupled massless Dirac electrons withs-wave superconducting pairing. As a result of the spin-orbit coupling, our model has only two kinds of linearly dispersing modes, and we take these to be right-moving spin-up and left-moving spin-down. Both lattice and continuum models are studied. In the lattice model, we find that a single Majorana zero energy mode appears at each end of a finite system provided that thes-wave pairing has an extended form, with the nearest-neighbor pairing being larger than the on-site pairing. We confirm this both numerically and analytically by calculating the winding number. We find that the continuum model also has zero energy end modes. Next we study a lattice version of a model with both Schrödinger and Dirac-like terms and find that the model hosts a topological transition between topologically trivial and non-trivial phases depending on the relative strength of the Schrödinger and Dirac terms. We then study a continuum system consisting of twos-wave superconductors with different phases of the pairing, with aδ-function potential barrier lying at the junction of the two superconductors. Remarkably, we find that the system has asingleAndreev bound state (ABS) which is localized at the junction. When the pairing phase difference crosses a multiple of 2π, an ABS touches the top of the superconducting gap and disappears, and a different state appears from the bottom of the gap. We also study the AC Josephson effect in such a junction with a voltage bias that has both a constantV₀and a term which oscillates with a frequencyω. We find that, in contrast to standard Josephson junctions, Shapiro plateaus appear when the Josephson frequencyω_J= 2eV₀/ℏis a rational fraction ofω. We discuss experiments which can realize such junctions.

A comparative study of effects of omega-3 Fatty acids, alpha lipoic Acid and vitamin e in type 2 diabetes mellitus

BACKGROUND

Diabetes Mellitus is a metabolic disorder characterized by abnormal lipid and glucose metabolism. Various modes of adjuvant therapy have been advocated to ameliorate insulin resistance.

AIM

This study was intended to assess the effects of antioxidants; alpha lipoic acid (ALA), omega 3 fatty acid and vitamin E on parameters of insulin sensitivity (blood glucose and HbA1c) in patients of type 2 diabetes mellitus with documented insulin resistance.

SUBJECTS AND METHODS

It was a prospective, randomized, double blind, placebo controlled, single centered study. 104 patients with type 2 diabetes mellitus with insulin resistance were recruited. They were given ALA, omega 3 fatty acid, vitamin E or placebo. Fasting blood glucose and HbA1c were measured at first visit (V1) and after 90 days (V2). Statistical analysis was carried out by paired t-test by using SPSS software version 11 (SPSS, Chicago, USA).

RESULTS

Analysis of baseline (V1) vs. end of treatment period (V2) parameters, showed significant decrease in HbA1c in the three treatment group. We also observed decrease in fasting blood glucose in the three treatment group but it was not statistically significant (Gr. I = 0.51, Gr. II = 0.05, Gr. III = 0.22, Gr. IV = 0.88).

CONCLUSION

ALA, Omega 3 fatty acid and vitamin E can be used as add on therapy in patients with type 2 diabetes mellitus to improve insulin sensitivity and lipid metabolism.

Standardising analogue front end design for ultrasound imaging systems

The standardisation of analogue front end products is allowing the development of portable ultrasound devices that provide enhanced image quality while minimising power consumption. The design opportunities associated with the use of these products are described.