Absence of edge reconstruction for quantum Hall edge channels in graphene devices.

Quantum Hall (QH) edge channels propagating along the periphery of two-dimensional (2D) electron gases under perpendicular magnetic field are a major paradigm in physics. However, groundbreaking experiments that could use them in graphene are hampered by the conjecture that QH edge channels undergo a reconstruction with additional nontopological upstream modes. By performing scanning tunneling spectroscopy up to the edge of a graphene flake on hexagonal boron nitride, we show that QH edge channels are confined to a few magnetic lengths at the crystal edges.

Imaging tunable quantum Hall broken-symmetry orders in graphene.

When electrons populate a flat band their kinetic energy becomes negligible, forcing them to organize in exotic many-body states to minimize their Coulomb energy. The zeroth Landau level of graphene under a magnetic field is a particularly interesting strongly interacting flat band because interelectron interactions are predicted to induce a rich variety of broken-symmetry states with distinct topological and lattice-scale orders. Evidence for these states stems mostly from indirect transport experiments that suggest that broken-symmetry states are tunable by boosting the Zeeman energy or by dielectric screening of the Coulomb interaction.

Helical quantum Hall phase in graphene on SrTiO.

The ground state of charge-neutral graphene under perpendicular magnetic field was predicted to be a quantum Hall topological insulator with a ferromagnetic order and spin-filtered, helical edge channels. In most experiments, however, an insulating state is observed that is accounted for by lattice-scale interactions that promote a broken-symmetry state with gapped bulk and edge excitations. We tuned the ground state of the graphene zeroth Landau level to the topological phase through a suitable screening of the Coulomb interaction with the high dielectric constant of a strontium titanate (SrTiO) substrate.

Asymptomatic rectal and bladder endometriosis: a case for robotic-assisted surgery.

Objectives: To evaluate the feasibility and safety of robot-assisted laparoscopic partial cystectomy for the treatment of rectal and bladder endometriosis.

Materials And Methods: A 23 year-old female with history of infertility and pelvic pain was found to have a 4 cm bladder mass and rectal nodule on pelvic ultrasonography. Patient denied any other genitourinary symptoms.

Initial experience with successful totally robotic laparoscopic cystoprostatectomy and ileal conduit construction in tetraplegic patients: report of two cases.

Purpose: To evaluate the feasibility and safety of totally robotic laparoscopic cystoprostatectomy for neurogenic bladder, with intracorporeal ileal-conduit urinary diversion in tetraplegic patients with severe neurogenic bladder complications.

Patients And Methods: Two men, 41 and 38 years old, with complete post-traumatic C7-C8 quadriplegia and poor lower urinary-tract condition underwent totally transperitoneally performed cystoprostatectomy and ileal-conduit urinary diversion with robotic assistance (Da Vinci).

Results: The procedures were completed without open conversion.