4 research outputs found
Electrostatically-induced strain of graphene on GaN nanorods
Few-layer graphene deposited on semiconductor nanorods separated by undoped
spacers has been studied in perspective for the fabrication of stable
nanoresonators. We show that an applied bias between the graphene layer and the
nanorod substrate affects the graphene electrode in two ways: 1) by a change of
the carrier concentration in graphene and 2) by inducing strain, as
demonstrated by the Raman spectroscopy. The capacitance of the investigated
structures scales with the area of graphene in contact with the nanorods. Due
to the reduced contact surface, the efficiency of graphene gating is one order
of magnitude lower than for a comparable structure without nanorods. The shift
of graphene Raman modes observed under bias clearly shows the presence of
electrostatically-induced strain and only a weak modification of carrier
concentration, both independent of number of graphene layers. A higher impact
of bias on strain was observed for samples with a larger contact area between
the graphene and the nanorods which shows perspective for the construction of
sensors and nanoresonator devices
Neurological symptoms in hospitalised patients with COVID-19 and their association with in-hospital mortality
Objectives. To evaluate the spectrum of neurological symptoms in patients with COVID-19 during the first 14 days of hospitalisation and its association with in-hospital mortality. Material and methods. We included 200 patients with RT-PCR-confirmed COVID-19 admitted to University Hospital in Krakow, Poland. In 164 patients, a detailed questionnaire concerning neurological symptoms and signs was performed prospectively within 14 days of hospitalisation. In the remaining 36 patients, such questionnaires were completed retrospectively based on daily observations in the Department of Neurology. Results. During hospitalisation, 169 patients (84.5%) experienced neurological symptoms; the most common were: fatigue (62.5%), decreased mood (45.5%), myalgia (43.5%), and muscle weakness (42.5%). Patients who died during hospitalisation compared to the remainder were older (79 [70.5–88.5] vs. 63.5 [51–77] years, p = 0.001), and more often had decreased level of consciousness (50.0% vs. 9.3%, p < 0.001), delirium (33.3% vs. 4.4%, p < 0.001), arterial hypotension (50.0% vs. 19.6%, p = 0.005) or stroke during (18.8% vs. 3.3%, p = 0.026) or before hospitalisation (50.0% vs. 7.1, p < 0.001), whereas those who survived more often suffered from headache (42.1% vs. 0%, p = 0.012) or decreased mood (51.7% vs. 0%, p = 0.003).
Conclusions. Most hospitalised patients with COVID-19 experience neurological symptoms. Decreased level of consciousness, delirium, arterial hypotension, and stroke during or before hospitalisation increase the risk of in-hospital mortality