Significance of the tethered maxillary frenulum: a questionnaire-based observational cohort study.

Background: The clinical significance of lip-tie, or a tethered maxillary frenulum, remains under debate. Clinicians and parents are often perplexed when deciding whether procedures available to relieve a seemingly tight or severe maxillary frenulum are needed.

Purpose: No previous studies have assessed the consequences of not subjecting a tethered maxillary frenulum in newborns to surgical intervention.

Calcium level during the first trimester of pregnancy as a predictor of preeclampsia.

Objective: To examine the association between calcium levels during the first trimester of pregnancy and preeclampsia.

Methods: The study population included registered births (n = 5233) in a tertiary medical center between 2001 and 2011. A comparison was performed between women with and without hypocalcemia during the first trimester of pregnancy.

Theory and modeling of electrically tunable metamaterial devices using inter-subband transitions in semiconductor quantum wells.

In this paper, we propose a new and versatile mechanism for electrical tuning of planar metamaterials: strong coupling of metamaterial resonances to engineered intersubband transitions that can be tuned through the application of an electrical bias. We present the general formalism that allows calculating the permittivity tensor for intersubband transitions in generic semiconductor heterostructures and we study numerically the specific case of coupling and tuning metamaterials in the thermal infrared through coupling to biased GaAs semiconductor quantum wells. This tuning mechanism can be scaled from the visible to the far infrared by the proper choice of metamaterials and semiconductor heterostructures.

Active tuning of mid-infrared metamaterials by electrical control of carrier densities.

We demonstrate electrically-controlled active tuning of mid-infrared metamaterial resonances using depletion-type devices. The depletion width in an n-doped GaAs epilayer changes with an electric bias, inducing a change of the permittivity of the substrate and leading to frequency tuning of the resonance. We first present our detailed theoretical analysis and then explain experimental data of bias-dependent metamaterial transmission spectra.

Fermi edge polaritons in a microcavity containing a high density two-dimensional electron gas.

Sharp, near band gap lines are observed in the reflection and photoluminescence spectra of GaAs/AlGaAs structures consisting of a modulation doped quantum well (MDQW) that contains a high density two-dimensional electron gas (2DEG) and is embedded in a microcavity (MC). The energy dependence of these lines on the MC-confined photon energy shows level anticrossings and Rabi splittings very similar to those observed in systems of undoped QW's embedded in a MC. The spectra are analyzed by calculating the optical susceptibility of the MDQW in the near band gap spectral range and using it within the transfer matrix method.

[Recommendations for optimising the treatment of multiple sclerosis in Latin America].

Introduction: Multiple sclerosis (MS) is the most common primary demyelinating disease affecting the central nervous system. In recent years the development of new drugs that have been shown to modify the natural history of MS have had a substantial impact on the treatment of the disease.

Aims: To harmonise and integrate the evidence available on optimising the treatment of patients with MS.