Convolutional sparse coding for high dynamic range imaging

Current HDR acquisition techniques are based on either (i) fusing multibracketed, low dynamic range (LDR) images, (ii) modifying existing hardware and capturing different exposures simultaneously with multiple sensors, or (iii) reconstructing a single image with spatially-varying pixel exposures. In this paper, we propose a novel algorithm to recover high-quality HDRI images from a single, coded exposure. The proposed reconstruction method builds on recently-introduced ideas of convolutional sparse coding (CSC); this paper demonstrates how to make CSC practical for HDR imaging. We demonstrate that the proposed algorithm achieves higher-quality reconstructions than alternative methods, we evaluate optical coding schemes, analyze algorithmic parameters, and build a prototype coded HDR camera that demonstrates the utility of convolutional sparse HDRI coding with a custom hardware platform

Thermal stress analysis of variable angle tow composite plates through high-order structural models

This work focuses on thermo-elastic analysis of Variable Angle Tow (VAT) composite plates. Emphasis is given to the through-the-thickness 3D stress component distributions as a consequence of constant temperature profiles. High-order structural models are used, in order to take into account the volumetric and the distortion contributions. The last contribute arise from boundary conditions or asymmetric staking sequences. Governing equations of the uncoupled thermo-elastic problem are derived in the domain of the Carrera Unified Formulation (CUF), which in turn is coupled with a classical finite element method to obtain opportune numerical solutions. The advantage of using CUF lies in the fact that different theories of structures can be implemented automatically and a critical study on the use of standard to high-order plate finite elements can be performed with ease. In this manner we classify models based on their efficiency and depending on the degree of accuracy needed, both in terms of displacements and stresses. Different numerical problems are considered and it is demonstrated that layerwise approximations are needed whenever shear stresses trends are of interest. Boundary Conditions influence more the choice of the adequate expansion theory otherwise

Long Exciton Dephasing Time and Coherent Phonon Coupling in CsPbBr2_{2}Cl Perovskite Nanocrystals

Fully-inorganic cesium lead halide perovskite nanocrystals (NCs) have shown to exhibit outstanding optical properties such as wide spectral tunability, high quantum yield, high oscillator strength as well as blinking-free single photon emission and low spectral diffusion. Here, we report measurements of the coherent and incoherent exciton dynamics on the 100 fs to 10 ns timescale, determining dephasing and density decay rates in these NCs. The experiments are performed on CsPbBr$_{2}$Cl NCs using transient resonant three-pulse four-wave mixing (FWM) in heterodyne detection at temperatures ranging from 5 K to 50 K. We found a low-temperature exciton dephasing time of 24.5$\pm$1.0 ps, inferred from the decay of the photon-echo amplitude at 5 K, corresponding to a homogeneous linewidth (FWHM) of 54$\pm$5 {\mu}eV. Furthermore, oscillations in the photon-echo signal on a picosecond timescale are observed and attributed to coherent coupling of the exciton to a quantized phonon mode with 3.45 meV energy

Chemically-specific dual/differential CARS micro-spectroscopy of saturated and unsaturated lipid droplets

We have investigated the ability of dual-frequency Coherent Antistokes Raman Scattering (D-CARS) micro-spectroscopy, based on femtosecond pulses (100 fs or 5 fs) spectrally focussed by glass dispersion, to distinguish the chemical composition of micron-sized lipid droplets consisting of different triglycerides types (poly-unsaturated glyceryl trilinolenate, mono-unsaturated glyceryl trioleate and saturated glyceryl tricaprylate and glyceryl tristearate) in a rapid and label-free way. A systematic comparison of Raman spectra with CARS and D-CARS spectra was used to identify D-CARS spectral signatures which distinguish the disordered poly-unsaturated lipids from the more ordered saturated ones both in the CH-stretch vibration region and in the fingerprint region, without the need for lengthy CARS multiplex acquisition and analysis. D-CARS images of the lipid droplets at few selected wavenumbers clearly resolved the lipid composition differences, and exemplify the potential of this technique for label-free chemically selective rapid imaging of cytosolic lipid droplets in living cell

ROBOT-MEDIATED AND CLINICAL SCALES EVALUATION AFTER UPPER LIMB BOTULINUM TOXIN TYPE A INJECTION IN CHILDREN WITH HEMIPLEGIA

Objective: The aim of this pilot study was to examine changes in different aspects of impairment, including spasticity in the upper limbs, of hemiplegic children following botulinum toxin type A intervention. Progress was assessed using standard clinical measurements and a robotic device. Design: Pre-post multiple baseline. Subjects: Six children with hemiplegia. Methods: Botulinium toxin type A injections were administered into the affected upper limb muscles. Outcomes were evaluated before and one month after the injection. Outcome assessments included: Melbourne Scale, Modified Ashworth Scale (MAS) and Passive Range of Motion. Furthermore, a robotic device was employed as an evaluation tool. Results: Patients treated with botulinum toxin type A had significantly greater reduction in spasticity (MAS, p < 0.01), which explains an improvement in upper limb function and quality movement measured with the Melbourne Scale (p < 0.01). These improvements are consistent with robot-based evaluation results that showed statistically significant changes (p < 0.01) following botulinum toxin type A injections. Conclusion: The upper limb performs a wide variety of movements. The multi-joint nature of the task during the robotmediated evaluation required active control of joint interaction forces. There was good correlation between clinical scales and robotic evaluation. Hence the robot-mediated assessment may be used as an additional tool to quantify the degree of motor improvement after botulinum toxin type A injections

Design, Computational Modelling and Experimental Characterization of Bistable Hybrid Soft Actuators for a Controllable-Compliance Joint of an Exoskeleton Rehabilitation Robot

This paper presents the mechatronic design of a biorobotic joint with controllable compliance, for innovative applications of “assist-as-needed” robotic rehabilitation mediated by a wearable and soft exoskeleton. The soft actuation of robotic exoskeletons can provide some relevant advantages in terms of controllable compliance, adaptivity and intrinsic safety of the control performance of the robot during the interaction with the patient. Pneumatic Artificial Muscles (PAMs), which belong to the class of soft actuators, can be arranged in antagonistic configuration in order to exploit the variability of their mechanical compliance for the optimal adaptation of the robot performance during therapy. The coupling of an antagonistic configuration of PAMs with a regulation mechanism can achieve, under a customized control strategy, the optimal tuning of the mechanical compliance of the exoskeleton joint over full ranges of actuation pressure and joint rotation. This work presents a novel mechanism, for the optimal regulation of the compliance of the biorobotic joint, which is characterized by a soft and hybrid actuation exploiting the storage/release of the elastic energy by bistable Von Mises elastic trusses. The contribution from elastic Von Mises structure can improve both the mechanical response of the soft pneumatic bellows actuating the regulation mechanism and the intrinsic safety of the whole mechanism. A comprehensive set of design steps is presented here, including the optimization of the geometry of the pneumatic bellows, the fabrication process through 3D printing of the mechanism and some experimental tests devoted to the characterization of the hybrid soft actuation. The experimental tests replicated the main operating conditions of the regulation mechanism; the advantages arising from the bistable hybrid soft actuation were evaluated in terms of static and dynamic performance, e.g., pressure and force transition thresholds of the bistable mechanism, linearity and hysteresis of the actuator response

Resonantly excited exciton dynamics in two-dimensional MoSe2 monolayers

We report on the exciton and trion density dynamics in a single layer of MoSe2, resonantly excited and probed using three-pulse four-wave mixing (FWM), at temperatures from 300 K to 77 K. A multiexponential third-order response function for amplitude and phase of the heterodyne-detected FWM signal including four decay processes is used to model the data. We provide a consistent interpretation within the intrinsic band structure, not requiring the inclusion of extrinsic effects. We find an exciton radiative lifetime in the subpicosecond range consistent to what has been recently reported by Jakubczyk et al. [Nano Lett. 16, 5333 (2016)]. After the dominating radiative decay, the remaining exciton density, which has been scattered from the initially excited direct spin-allowed radiative state into dark states of different nature by exciton-phonon scattering or disorder scattering, shows a slower dynamics, covering 10-ps to 10-ns time scales. This includes direct spin-allowed transitions with larger in-plane momentum, as well as indirect and spin-forbidden exciton states. We find that exciton-exciton annihilation is not relevant in the observed dynamics, in variance from previous finding under nonresonant excitation. The trion density at 77 K reveals a decay of the order of 1 ps, similar to what is observed for the exciton. After few tens of picoseconds, the trion dynamics resembles the one of the exciton, indicating that trion ionization occurs on this time scale

Cardiac troponin T release after football 7 in healthy children and adults

The objective of this study was to compare the release of cardiac troponin T (cTnT) after a football 7 match between two cohorts of children and adult players. Thirty-six male football players (children = 24, adult = 12) played a football 7 match, and cTnT was measured before, and 3 h after exercise. Concentrations of cTnT were compared between groups and time, and correlated with participants’ characteristics, as well as internal and external exercise load. Cardiac troponin T was elevated in all participants (p < 0.001), and exceeded the upper reference limit for myocardial infarction in 25 (~70%) of them. Baseline concentrations were higher in adults (p < 0.001), but the elevation of cTnT was comparable between the groups (p = 0.37). Age (p < 0.001), body mass (p = 0.001) and height (p < 0.001), and training experience (p = 0.001) were associated to baseline cTnT values, while distance (p < 0.001), mean speed (p < 0.001), and peak (p = 0.013) and mean (p = 0.016) heart rate were associated to the elevation of cTnT. The present study suggests that a football 7 match evoked elevations of cTnT during the subsequent hours in healthy players regardless of their age. However, adults might present higher resting values of cTnT than children. In addition, results suggest that the exercise-induced elevations of cTnT might be mediated by exercise load but not participant characteristics

Nutrition knowledge and care practices of home-based caregivers in Vhembe District, South Africa

Background: Home-based care is provided to clients in their homes to promote and maintain good health, hygiene and nutrition. Objective: This study assessed nutrition knowledge and care practices of home-based caregivers in Vhembe District, South Africa. Methods: The design was cross sectional, descriptive and exploratory using quantitative and qualitative approaches. Multistage sampling was used, with convenient selection of two municipalities from four, eight home-based care agencies randomly selected from 96 agencies, 128 caregivers conveniently selected for interviews, 92 caregivers selected for focus group discussions and 28 caregivers selected for observation during home visits. Demographic characteristics, nutrition knowledge and care practices were evaluated using questionnaires, interview guides and observational checklists. Data were analysed using SPSS 22 and thematic analysis for qualitative data. Results: caregivers (99.2%) were women, 68.7% had secondary education and all had received 59-day training and 64.1% had six to ten years of home-based care experience. Only 0.8% had adequate nutrition knowledge, 45.3% satisfactory knowledge and 53.9% limited to no knowledge. Most care practices reported during the focus group discussions were not observed during home visits. Conclusion: Nutrition knowledge and care practices of HBC in Vhembe District were found to be inadequate. The nutrition content in the training package should be improved