Charge doping and large lattice expansion in oxygen-deficient heteroepitaxial WO3

Tungsten trioxide is a versatile material with widespread applications ranging from electrochromic and optoelectronic devices to water splitting and catalysis of chemical reactions. For technological applications, thin films of WO3 are particularly appealing, taking advantage from high surface-to-volume ratio and tunable physical properties. However, the growth of stoichiometric, crystalline thin films is challenging because the deposition conditions are very sensitive to the formation of oxygen vacancies. In this work, we show how background oxygen pressure during pulsed laser deposition can be used to tune the structural and electronic properties of WO3 thin films. By performing X-ray diffraction and low-temperature transport measurements, we find changes in WO3 lattice volume up to 10%, concomitantly with an insulator-to-metal transition as a function of increased level of electron doping. We use advanced ab initio calculations to describe in detail the properties of the oxygen vacancy defect states, and their evolution in terms of excess charge concentration. Our results depict an intriguing scenario where structural, electronic, optical, and transport properties of WO3 single-crystal thin films can all be purposely tuned by a suited control of oxygen vacancies formation during growth

Superconducting quantum point contact with split gates in the two dimensional LaAlO3/SrTiO3 superfluid

One of the hallmark experiments of quantum transport is the observation of the quantized resistance in a point contact formed with split gates in GaAs/AlGaAs heterostructures. Being carried out on a single material, they represent in an ideal manner equilibrium reservoirs which are connected only through a few electron mode channel with certain transmission coefficients. It has been a long standing goal to achieve similar experimental conditions also in superconductors, only reached in atomic scale mechanically tunable break junctions of conventional superconducting metals, but here the Fermi wavelength is so short that it leads to a mixing of quantum transport with atomic orbital physics. Here we demonstrate for the first time the formation of a superconducting quantum point contact (SQPC) with split gate technology in a superconductor, utilizing the unique gate tunability of the two dimensional superfluid at the LaAlO3/SrTiO3 (LAO/STO) interface. When the constriction is tuned through the action of metallic split gates we identify three regimes of transport: (i) SQPC for which the supercurrent is carried only by a few quantum transport channels. (ii) Superconducting island strongly coupled to the equilibrium reservoirs. (iii) Charge island with a discrete spectrum weakly coupled to the reservoirs. Our experiments demonstrate the feasibility of a new generation of mesoscopic all-superconductor quantum transport devices.Comment: 18 page

On the comparison of oxygen and sulfur transfer reactivities in phosphine and phosphorene: the case of R3Sb(X) carriers (X = O or S).

A mediated approach for an efficient metal covalent functionalization of the phosphorene surface is presented through the selective insertion of chalcogen atoms. Electronic and steric requirements have been evaluated in details

Comparison of fatty acid profile in lamb meat and baby food based on lamb meat

The aim of this study was to compare the fatty acid (FA) profile of fresh lamb meat with those of baby foods based on lamb meat. For this purpose, samples of commercial homogenized (HO) and lyophilized (LIO) baby food based on lamb meat and fresh lamb meat (FM) were analyzed for their FA composition. All fatty acids, except for oleic acid and conjugated linoleic acid (CLA), differed among the three baby products tested. The sum of omega-6 FA and the ratio omega 6/omega 3 FA were lower in FM and LIO meat compared to HO samples. The content of total PUFA n-3 was the highest in FM, because of its highest content of C18:3 n3, EPA, DPA and DHA compared to LIO and HO baby food. The content of arachidonic acid was more than 6-fold higher in FM compared to LIO and HO. This study evidenced the possibility of enhancing the FA profile of commercial baby food based on lamb meat by using meat with healthier FA profile

Predicting carer health effects using patient data

Illnesses and interventions can affect the health status of family carers in addition to patients. However economic evaluation studies rarely incorporate data on health status of carers.We investigated whether changes in carer health status could be 'predicted' from the health data of those they provide care to (patients), as a means of incorporating carer outcomes in economic evaluation.We used a case study of the family impact of meningitis, with 497 carer-patient dyads surveyed at two points. We used regression models to analyse changes in carers' health status, to derive predictive algorithms based on variables relating to the patient. We evaluated the predictive accuracy of different models using standard model fit criteria.It was feasible to estimate models to predict changes in carers' health status. However, the predictions generated in an external testing sample were poorly correlated with the observed changes in individual carers' health status. When aggregated, predictions provided some indication of the observed health changes for groups of carers.At present, a 'one-size-fits-all' predictive model of carer outcomes does not appear possible and further research aimed to identify predictors of carer's health status from (readily available) patient data is recommended. In the meanwhile, it may be better to encourage the targeted collection of carer data in primary research to enable carer outcomes to be better reflected in economic evaluation

Translational approaches in neurorehabilitation: from Researcher’s bench to Patient’s bedside

Aim: To translate evidence-based methodologies of functional assessment and training from exercise and sports physiology to patients with neurological conditions. Methods: Dynamometric, neurophysiological and clinico-functional assessments were comprehensively performed within a multi-layered agenda consisting of different trials (3 randomized controlled trials, 5 cross-sectional studies, 4 single-group proof-of concept interventional trials) conducted on both healthy subjects and individuals presenting neurological conditions with a special focus on multiple sclerosis. These studies were aimed at addressing muscle weakness and its related disabilities, with a specific focus on multiple sclerosis. Results: Employing exercise and sports physiology techniques and methods with neurological patients, mostly multiple sclerosis, resulted into dynamometric and clinico-functional improvements which exceeded those commonly reported in clinical literature. In particular, the choice of strengthening exercise performed at maximal intensity proved well tolerated and effective in addressing muscle weakness due to neurological conditions. Moreover, assessment techniques borrowed from elite sports helped highlighting and characterizing the main differences between healthy and neurological individuals in terms of force production patterns and overall muscle capability. Conclusion: Translational approaches like those explored in the present PhD project are to be considered as promising and innovative tools in the management of motor disabilities caused by pathological conditions of the nervous system