Temperature induced modulation of resonant Raman scattering in bilayer 2H-MoS2.

The temperature evolution of the resonant Raman scattering from high-quality bilayer 2H-MoS[Formula: see text] encapsulated in hexagonal BN flakes is presented. The observed resonant Raman scattering spectrum as initiated by the laser energy of 1.96 eV, close to the A excitonic resonance, shows rich and distinct vibrational features that are otherwise not observed in non-resonant scattering. The appearance of 1st and 2nd order phonon modes is unambiguously observed in a broad range of temperatures from 5 to 320 K. The spectrum includes the Raman-active modes, i.e. E[Formula: see text]([Formula: see text]) and A[Formula: see text]([Formula: see text]) along with their Davydov-split counterparts, i.e. E[Formula: see text]([Formula: see text]) and B[Formula: see text]([Formula: see text]). The temperature evolution of the Raman scattering spectrum brings forward key observations, as the integrated intensity profiles of different phonon modes show diverse trends. The Raman-active A[Formula: see text]([Formula: see text]) mode, which dominates the Raman scattering spectrum at T = 5 K quenches with increasing temperature. Surprisingly, at room temperature the B[Formula: see text]([Formula: see text]) mode, which is infrared-active in the bilayer, is substantially stronger than its nominally Raman-active A[Formula: see text]([Formula: see text]) counterpart.

Broadband and Tunable Light Harvesting in Nanorippled MoS2 Ultrathin Films.

Nanofabrication of flat optic silica gratings conformally layered with two-dimensional (2D) MoS2 is demonstrated over large area (cm2), achieving a strong amplification of the photon absorption in the active 2D layer. The anisotropic subwavelength silica gratings induce a highly ordered periodic modulation of the MoS2 layer, promoting the excitation of Guided Mode Anomalies (GMA) at the interfaces of the 2D layer. We show the capability to achieve a broadband tuning of these lattice modes from the visible (VIS) to the near-infrared (NIR) by simply tailoring the illumination conditions and/or the period of the lattice. Remarkably, we demonstrate the possibility to strongly confine resonant and nonresonant light into the 2D MoS2 layers via GMA excitation, leading to a strong absorption enhancement as high as 240% relative to a flat continuous MoS2 film. Due to their broadband and tunable photon harvesting capabilities, these large area 2D MoS2 metastructures represent an ideal scalable platform for new generation devices in nanophotonics, photo- detection and -conversion, and quantum technologies.

Ultra-broadband photon harvesting in large-area few-layer MoS2 nanostripe gratings.

Flat optics nanoarrays based on few-layer MoS2 are homogeneously fabricated over large-area (cm2) transparent templates, demonstrating effective tailoring of the photon absorption in two-dimensional (2D) transition-metal dichalcogenide (TMD) layers. The subwavelength subtractive re-shaping of the few-layer MoS2 film into a one-dimensional (1D) nanostripe array results in a pronounced photonic anomaly, tunable in a broadband spectral range by simply changing the illumination conditions (or the lattice periodicity). This scheme promotes efficient coupling of light to the 2D TMD layers via resonant interaction between the MoS2 excitons and the photonic lattice, with subsequent enhancement of absorption exceeding 400% relative to the flat layer. In parallel, an ultra-broadband absorption amplification in the whole visible spectrum is achieved, thanks to the non-resonant excitation of substrate guided modes promoted by MoS2 nanoarrays. These results highlight the potential of nanoscale re-shaped 2D TMD layers for large-area photon harvesting in layered nanophotonics, quantum technologies and new-generation photovoltaics.

Smartphone-based tele-electrocardiography support for primary care physicians reduces the pain-to-treatment time in acute coronary syndrome.

Background The Himachal Pradesh state acute coronary syndrome registry recorded a median delay of 13 h between the time of onset of pain to the time of making the diagnosis and giving treatment for acute coronary syndrome. We conducted a pilot study on providing 24-h tele-electrocardiography (Tele-ECG) services in the district Kangra of Himachal Pradesh, with the aim to reduce the time taken for diagnosis of acute coronary syndrome. Methods The intervention group for the study included eight rural community health centres, each with one to three primary care physicians, who were all unskilled in electrocardiogram interpretation. We provided them with 24-h Tele-ECG support. The primary care physicians used their smartphones to transmit the electrocardiogram image to the command centre, which was then read by the skilled specialist physicians in our medical college hospital and the report sent back within five minutes of having received the electrocardiogram. Antiplatelets were given by the primary care physician to patients diagnosed with acute coronary syndrome, who was then transported to the medical college hospital. The urban sub-divisional hospitals ( n = 6) formed the control group for the study. These hospitals had five to fifteen unskilled primary care physicians and one to two skilled specialist physicians; no intervention was done in this group. A pilot was run from February 2015-January 2016. Results We received 819 Tele-ECG consultations within the intervention group; 157 cases of acute coronary syndrome were confirmed and transferred to our medical college hospital facility. Similarly, we admitted 177 cases of acute coronary syndrome at the medical college hospital, who were first attended to by the primary care physician in the control group. Aspirin was administered to 91% and 58% of patients with acute coronary syndrome in the intervention and the control groups, respectively ( p < 0.0001). The median hospital-to-aspirin time (h) in the intervention and the control groups was 0.7 ± 1.45 h and 3.5 ± 10 h, respectively ( p < 0.0001). In the intervention group, 72% of the ST elevation myocardial infarction patients were diagnosed within 12 h by the primary care physician using Tele-ECG support. Interpretation and conclusions Smartphone-based Tele-ECG support for primary care physicians reduced the hospital-to-aspirin time in acute coronary syndrome significantly ( p < 0.0001). This is an effective low cost strategy and is easily replicable anywhere in the world.

Role of atom redeposition during rising ion flux in ion-induced nanodot self-assembly on GaSb surfaces.

In this study, a bottom-up approach of ion irradiation from hot cathode DC discharge plasma was used to investigate the role of energetic ion flux on the self-assembly of GaSb nanodots (NDs) at normal incidence. It was observed that, when increasing the flux in the range of 1014-1015 ions cm-2 s-1, the lateral dimension and root mean square (RMS) roughness of NDs is reduced even at constant temperature conditions in the ion energy range from 400-800 eV. The evolution of the surface morphology for different flux regimes is observed in a numerical integration simulation using the nonlinear isotropic damped Kuramoto-Sivashinsky (DKS) equation. By introducing a redeposition term, the DKS equation is found to be in good qualitative agreement with the experimental results. We have demonstrated the linear dependency of the redeposition coefficient on the ion flux and also reported the nonlinear dependency on the thermal diffusion coefficient, transition time, and characteristic length with the flux. In accordance with the nonlinearity, we have also discussed the effect of the variation of the ion flux on the RMS roughness and lateral dimension of NDs.

An unusual case of sustained ventricular tachycardia following a wasp bite.

Sustained ventricular tachycardia (VT) is a life-threatening condition which requires immediate intervention. We report a case of unusual etiology of sustained VT in a 42-year-old male after a wasp bite in the absence of anaphylaxis. The patient was treated with amiodarone and improved within 48 h. Thus, wasp stings can lead to serious tachyarrhythmias which can be life-threatening. Emergency care physicians should be aware of such arrhythmias in the setting of wasp bites which can be fatal.