How I treat brain metastases of melanoma.

Brain metastases are common in advanced melanoma and cause death in >50% of patients. Until recently, median survival was only ∼4 months. Improved systemic treatment including immune checkpoint inhibitors and combinations of BRAF/MEK inhibitors, however, has significantly improved intracranial tumor response and survival. In addition, advances in radiation therapy have also improved the intracranial outcomes for advanced melanoma patients with brain metastases (MBM). There has long been concern that systemic treatment of the central nervous metastases would be ineffective due to inability of active agents to cross an intact blood-brain barrier. Recent studies have shown, however, that highly active systemic therapy can have significant benefit in these patients. When determining a patient's treatment, the important factors in predicting the likelihood of benefit including the presence of neurologic symptoms, the number and size of brain metastases, performance status/status of extracranial disease, and BRAF mutation status should all be considered. In this review, we will discuss the challenges and treatment options for patients with advanced melanoma and brain metastases.

Quantum Network of Atom Clocks: A Possible Implementation with Neutral Atoms.

We propose a protocol for creating a fully entangled Greenberger-Horne-Zeilinger-type state of neutral atoms in spatially separated optical atomic clocks. In our scheme, local operations make use of the strong dipole-dipole interaction between Rydberg excitations, which give rise to fast and reliable quantum operations involving all atoms in the ensemble. The necessary entanglement between distant ensembles is mediated by single-photon quantum channels and collectively enhanced light-matter couplings. These techniques can be used to create the recently proposed quantum clock network based on neutral atom optical clocks. We specifically analyze a possible realization of this scheme using neutral Yb ensembles.