Tumor Syndromes: Neurosurgical Evaluation and Management.

There are multiple syndromes associated with tumors of the central nervous system (CNS). The most common CNS tumor syndrome is neurofibromatosis-1, with well-defined major and minor criteria needed for diagnosis. Other syndromes with variable degree of CNS and extra-CNS involvement that the neurosurgeon should be aware of include neurofibromatosis-2; Turcot syndrome; Cowden syndrome; Gorlin syndrome; Li-Fraumeni syndrome; ataxia-telangiectasia; multiple endocrine neoplasia type 1; von Hippel-Lindau syndrome; and tuberous sclerosis complex. Although most CNS tumor syndromes follow an autosomal dominant pattern of inheritance, the genetic underpinnings of each disease are complex and increasingly better understood.

Quantum confinement in few layer SnS nanosheets.

Orthorhombic tin monosulfide (SnS) consists of layers of covalently bound Sn and S atoms held together by weak van der Waals forces and is a stable two-dimensional material with potentially useful properties in emerging applications such as valleytronics. Large-scale sustainable synthesis of few-layer (e.g., 1-10 layers) SnS is a challenge, which also slows progress in understanding their properties as a function of number of layers. Herein we describe solvothermal synthesis of SnS in water or ethylene glycol. The latter yields a flower-like morphology where the petals are SnS nanoplates and sonication and separation of these flowers via differential centrifugation yields 1-10 layer SnS nanoplates. The direct optical absorption edges of these SnS nanoplates blue-shift due to quantum confinement from 1.33 to 1.88 eV as the thickness (number of layers) is decreased from ∼5 nm (10 layers) to ∼2 nm (4 layers).