Quantum simulation of a Fermi-Hubbard model using a semiconductor quantum dot array.

Interacting fermions on a lattice can develop strong quantum correlations, which are the cause of the classical intractability of many exotic phases of matter. Current efforts are directed towards the control of artificial quantum systems that can be made to emulate the underlying Fermi-Hubbard models. Electrostatically confined conduction-band electrons define interacting quantum coherent spin and charge degrees of freedom that allow all-electrical initialization of low-entropy states and readily adhere to the Fermi-Hubbard Hamiltonian.

A force calibration standard for magnetic tweezers.

To study the behavior of biological macromolecules and enzymatic reactions under force, advances in single-molecule force spectroscopy have proven instrumental. Magnetic tweezers form one of the most powerful of these techniques, due to their overall simplicity, non-invasive character, potential for high throughput measurements, and large force range. Drawbacks of magnetic tweezers, however, are that accurate determination of the applied forces can be challenging for short biomolecules at high forces and very time-consuming for long tethers at low forces below ∼1 piconewton.

Double-stranded RNA under force and torque: similarities to and striking differences from double-stranded DNA.

RNA plays myriad roles in the transmission and regulation of genetic information that are fundamentally constrained by its mechanical properties, including the elasticity and conformational transitions of the double-stranded (dsRNA) form. Although double-stranded DNA (dsDNA) mechanics have been dissected with exquisite precision, much less is known about dsRNA. Here we present a comprehensive characterization of dsRNA under external forces and torques using magnetic tweezers.

Psychiatric symptoms causing delay in diagnosing childhood cancer: two case reports and literature review.

Introduction: A somatic disorder may initially be overlooked when a child presents with psychiatric symptoms. We report two children with anorexia nervosa as initial diagnosis and in whom there was a delay in the final diagnosis of the underlying malignancy. A literature survey was performed including patients under 18 years of age with psychiatric symptoms in whom later on an oncological diagnosis became evident as an explanation.