Neonatal Herpes Simplex Virus: Cutaneous Recurrence Is Common on Stopping Prophylactic Suppression Therapy.

Neonatal herpes simplex virus (HSV) infection is a potentially devastating disease. Data on the recurrence of disease while on suppressive therapy are limited. We reviewed cases of neonatal HSV. Prematurity was associated with more recurrence. No systemic or CNS recurrence occurred, but there were frequent recurrences of skin lesions.

Linearly polarized photoluminescence of InGaN quantum disks embedded in GaN nanorods.

We have investigated the emission from InGaN/GaN quantum disks grown on the tip of GaN nanorods. The emission at 3.21 eV from the InGaN quantum disk doesn't show a Stark shift, and it is linearly polarized when excited perpendicular to the growth direction. The degree of linear polarization is about 39.3% due to the anisotropy of the nanostructures. In order to characterize a single nanostructure, the quantum disks were dispersed on a SiO2 substrate patterned with a metal reference grid. By rotating the excitation polarization angle from parallel to perpendicular relative to the nanorods, the variation of overall PL for the 3.21 eV peak was recorded and it clearly showed the degree of linear polarization (DLP) of 51.5%.

Lesson of the month 2: A rare presentation of stroke: diagnosis made on magnetic resonance imaging.

Bilateral thalamic infarcts are uncommon posterior circulation strokes. The artery of Percheron (AOP) is a rare anatomical variant involving a singular arterial supply to both thalami and occlusion leads to bilateral thalamic infarction.We report the case of a 71-year-old man who presented with decreased consciousness (fluctuating Glasgow Coma Scale score of 5-7). He had a background of atrial fibrillation and was anticoagulated with dabigatran, a novel oral anticoagulant. Computed tomography (CT) scan showed a mildly reduced attenuation in the region of the left thamalus.Subsequent diffusion-weighted magnetic resonance imaging (MRI) showed acute brainstem infarction, extending into the thalamus bilaterally, likely due to AOP occlusion. Bilateral thalamic infarcts due to AOP occlusion may not be recognised on initial CT scan and are more readily seen using diffusion-weighted MRI, which is the most beneficial imaging modality to aid in early diagnosis and treatment.

Photonic molecules defined by SU-8 photoresist strips on a photonic crystal waveguide.

We present experimental and numerical investigations of photonic molecules obtained from laser patterned SU-8 photoresist strips on photonic crystal waveguides. Properties of cavities defined by a single strip are investigated and we show that two adjacent strips on a waveguide form a pair of optically coupled cavities. Simulation results and micro-photoluminescence mapping measurements demonstrate that the coupling strength is tunable by controlling the separation between the strips. Confocal mapping with decoupled collection and excitation points is used to explicitly show coupling between two cavities of a photonic molecule.

Optical fabrication and characterisation of SU-8 disk photonic waveguide heterostructure cavities.

In order to demonstrate cavity quantum electrodynamics using photonic crystal (PhC) cavities fabricated around self-assembled quantum dots (QDs), reliable spectral and spatial overlap between the cavity mode and the quantum dot is required. We present a method for using photoresist to optically fabricate heterostructure cavities in a PhC waveguide with a combined photolithography and micro-photoluminescence spectroscopy system. The system can identify single QDs with a spatial precision of ±25 nm, and we confirm the creation of high quality factor cavity modes deterministically placed with the same spatial precision. This method offers a promising route towards bright, on-chip single photon sources for quantum information applications.

Carrier trapping and confinement in Ge nanocrystals surrounded by Ge3N4.

We investigated the optical properties of Ge nanocrystals surrounded by Ge3N4. The broad emission ranging from infrared to blue is due to the dependence on the crystal size and preparation methods. Here, we report high resolution Photoluminescence (PL) attributed to emission from individual Ge nanocrystals (nc-Ge) spatially resolved using micro-photoluminescence and detailed using temperature and power-dependent photoluminescence studies. The measured peaks are shown to behave with excitonic characteristics and we argue that the spread of the nc-Ge peaks in the PL spectrum is due to different confinement energies arising from the variation in size of the nanocrystals.