Weak coupling of neurons enables very high-frequency and ultra-fast oscillations through the interplay of synchronized phase-shifts

Recently, in the past decade, high-frequency oscillations (HFOs), very high-frequency oscillations (VHFOs), and ultra-fast oscillations (UFOs) were reported in epileptic patients with drug-resistant epilepsy. However, to this day, the physiological origin of these events has yet to be understood. Our study establishes a mathematical framework based on bifurcation theory for investigating the occurrence of VHFOs and UFOs in depth EEG signals of patients with focal epilepsy, focusing on the potential role of reduced connection strength between neurons in an epileptic focus. We demonstrate that synchronization of a weakly coupled network can generate very and ultra high-frequency signals detectable by nearby microelectrodes. In particular, we show that a bistability region enables the persistence of phase-shift synchronized clusters of neurons. This phenomenon is observed for different hippocampal neuron models, including Morris-Lecar, Destexhe-Paré, and an interneuron model. The mechanism seems to be robust for small coupling, and it also persists with random noise affecting the external current. Our findings suggest that weakened neuronal connections could contribute to the production of oscillations with frequencies above 1000Hz, which could advance our understanding of epilepsy pathology and potentially improve treatment strategies. However, further exploration of various coupling types and complex network models is needed

Neuroloogilise seisundi varajase halvenemise sagedus pärast trombolüüsi ja seda mõjutavad tegurid: SITS registri andmed

Eesti Arst 2021; 100(4):241 &nbsp

Association of Baseline Hyperglycaemia with Outcomes of Diabetic and Non-diabetic Acute Ischaemic Stroke Patients treated with Intravenous Thrombolysis : a Propensity Score Matched Analysis from the SITS-ISTR registry

© 2019 by the American Diabetes Association.Peer reviewedPostprin

The incidence and associated factors of early neurological deterioration after thrombolysis: Results from SITS Registry

Background and purpose: Early neurological deterioration (END) after stroke onset may predict severe outcomes. Estimated rates of END after intravenous thrombolysis among small patient samples have been reported up to 29.8%. We studied the incidence and factors associated with END among patients following intravenous thrombolysis. Methods: We analyzed SITS-International Stroke Thrombolysis registry patients with known outcomes enrolled in 2010 to 2017. END was defined as an increase in National Institutes of Health Stroke Scale score ≥4 or death within 24 hours from baseline National Institutes of Health Stroke Scale. We determined the incidence of END and used logistic regression models to inspect its associated factors. We adjusted for variables found significant in univariate analyses (P<0.05). Main outcomes were incidence of END, associated predictors of END, ordinal day-90 mRS, and day-90 mortality. Results: We excluded 53 539 patients and included 50 726 patients. The incidence of END was 3415/50 726 (6.7% [95% CI, 6.5%–7.0%]). Factors independently associated with END on multivariate analysis were intracerebral hemorrhage (OR, 3.23 [95% CI, 2.96–3.54], P<0.001), large vessel disease (LVD) with carotid stenosis (OR, 2.97 [95% CI, 2.45–3.61], P<0.001), other LVD (OR, 2.41 [95% CI, 2.03–2.88], P<0.001), and ischemic stroke versus transient ischemic attack (TIA)/stroke mimics (OR, 16.14 [95% CI, 3.99–65.3], P<0.001). END was associated with worse outcome on ordinal mRS: adjusted OR 2.48 (95% CI, 2.39–2.57, P<0.001) by day-90 compared with no END. The adjusted OR for day-90 mortality was 9.70 (95% CI, 8.36–11.26, P<0.001). Conclusions: The routinely observed rate of END reflected by real-world data is low, but END greatly increases risk of disability and mortality. Readily identifiable factors predict END and may help with understanding causal mechanisms to assist prevention of END

Association of statin pre-treatment with baseline stroke severity and outcome in patients with acute ischemic stroke and received reperfusion treatment: An observational study

[Backgroun] Statins have an important role in stroke prevention, especially in high-risk populations and may also affect the initial stroke severity and outcomes in patients taking them before an ischemic stroke.[Aims] Our aim was to evaluate the association of statin pre-treatment with the severity in acute ischemic stroke (AIS).[Methods] We analyzed AIS patients received intravenous thrombolysis (IVT) and/or endovascular thrombectomy (EVT) and recorded in the SITS International Thrombolysis and Thrombectomy Registry from 2011 to 2017. We identified patients with statin information at baseline. The primary outcome was baseline National Institutes of Health Stroke Scale (NIHSS) score. Secondary outcomes were NIHSS score at 24 h, symptomatic intracerebral hemorrhage (SICH) and functional outcome at 90 days after acute intervention. Multivariable linear and logistic regression and propensity score matching (PSM) was used to quantify the effect of statin pre-treatment.[Results] Of 93,849 patients, 23,651 (25.2%) were treated with statins prior the AIS. Statin pre-treatment group was older and had higher comorbidity. Median NIHSS at baseline was similar between groups. In the adjusted and PSM analysis, statin pre-treatment was inversely associated with baseline NIHSS (odds ratio (OR) = 0.77, 95% confidence interval (CI) = 0.6–0.99 and OR for PSM 0.73, 95% CI = 0.54–0.99, p = 0.004) and independently associated with mild stroke defined as NIHSS ⩽8 in adjusted and PSM analysis (OR = 1.21, 95% CI = 1.1–1.34, p < 0.001 and OR for PSM 1.17, 95% CI = 1.05–1.31, p = 0.007). Regarding secondary outcomes, there were no differences in functional outcomes, death nor SICH rates between groups.[Conclusion] Prior treatment with statins was associated with lower NIHSS at baseline. However, this association did not translate into any difference regarding functional outcome at 90 days. No association was found regarding SICH. These findings indicate the need of further studies to assess the effect on statin pre-treatment on initial stroke severity.Peer reviewe

Supplemental material for Association of statin pre-treatment with baseline stroke severity and outcome in patients with acute ischemic stroke and received reperfusion treatment: An observational study

Supplemental material, sj-docx-1-wso-10.1177_17474930221095965 for Association of statin pre-treatment with baseline stroke severity and outcome in patients with acute ischemic stroke and received reperfusion treatment: An observational study by Irene Escudero-Martínez, Marius Matusevicius, Ana Pavia-Nunes, Petr Sevcik, Miroslava Nevsimalova, Viiu-Marika Rand, Janika Kõrv, Manuel Cappellari, Robert Mikulik, Danilo Toni and Niaz Ahmed in International Journal of Stroke.Boehringer Ingelheim.Peer reviewe

Development of an anti-flood board to protect the interiors and exteriors of the infrastructure

This article deals with the development of an anti-flood board to protect the interior and exterior of various infrastructures, such a houses, cottages or industrial buildings. It was designed prototypes and assembled numerical simulations. In Central Europe and in particular in the Czech Republic, floods are an integral part of the natural water cycle and cause great loss of life and great property damage. The development of new types of mobile anti-flood boards is very important as the design solution is developed for flood protection with regard to minimizing weight, cost of production, easy manipulation, simplicity and speed of installation

Development of an anti-flood board to protect the interiors and exteriors of the infrastructure

This article deals with the development of an anti-flood board to protect the interior and exterior of various infrastructures, such a houses, cottages or industrial buildings. It was designed prototypes and assembled numerical simulations. In Central Europe and in particular in the Czech Republic, floods are an integral part of the natural water cycle and cause great loss of life and great property damage. The development of new types of mobile anti-flood boards is very important as the design solution is developed for flood protection with regard to minimizing weight, cost of production, easy manipulation, simplicity and speed of installation

Characterization of vaterite synthesized at various temperatures and stirring velocities without use of additives

Conditions for the synthesis of vaterite without additives have been investigated (T = 30 – 90°C, stirring velocity=200–600rpm). The obtained different CaCO3 polymorphs were characterized with Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM). Quantitative phase analysis (QPA) was performed by the Rietveld method. To describe vaterite diffraction patterns, two structural models were employed. Their relative abundance was found to change with the temperature of synthesis. The optimal synthesis conditions for preparing pure vaterite (≥99 wt.%) were found at 60°C and 600 rpm. This is the first time pure vaterite is obtained at such high temperature without additives. The conditions under which the different polymorphs formed, and their microstructural features, are discussed. In addition, nanoindentation measurements on synthesized vaterite and calcite are firstly reported. The vaterite elastic modulus is higher than that of calcite (E = 16–48 GPa and E = 9–35 GPa, respectively), whereas the range in hardness was found to be the same for both polymorphs (H=0.4–2.8).Depto. de Pintura y Conservación-RestauraciónFac. de Bellas ArtesTRUEpu

Determination of optimal burning temperature ranges for production of natural hydraulic limes

There has been an increasing interest in the reproduction of natural hydraulic limes, as they are considered an appropriate material for conservation and restoration of historic buildings. This study assessed the influence of different calcination temperatures (850–1200 C) on the mineralogical composition and the reactivity of quicklime, as well as the setting time and the mechanical performance of mortar specimens. The limestone was acquired from a single quarry and contained 8.7% SiO2, 45% CaO. The results of XRPD and slaking reactivity of the produced quicklime confirmed a clear dependency on the calcination temperature. The performance properties of mortars made with the produced lime did not demonstrate a clear relation to the calcination temperature. The experiment confirmed that calcination temperatures from 850 to 1200 C can be used to produce natural hydraulic lime from the selected limestone. The optimal calcination temperature range from 1000 to 1100 C is recommended.Depto. de Pintura y Conservación-RestauraciónFac. de Bellas ArtesTRUEpu