The investigation of EPR paramagnetic probe line width and shape temperature dependence in high-temperature superconductors of Bi–Pb–Sr–Ca–Cu–O system

The work is related with the finding out of magnetic phases in strongly anisotropic high-temperature superconductor Bi1,7Pb0,3Sr2Ca2Cu3O10-δ in the temperature region where the superconductor is in the normal state. It was studied the temperature dependence of the paramagnetic probe EPR line width. In the normal state at T\u3eTc near 175 K it was revealed a pick in the temperature dependence of line width. In this region it was observed the time increase of the line width with the characteristic time ~ 17 min. This shows the possibility of magnetic phase formation in this material

Spectroscopic studies of defects in gamma- and neutron-irradiated magnesium aluminates spinel ceramics

The spectroscopic investigations of defects in optical spinel ceramics irradiated with gamma-rays from ⁶⁰Co source and mixed neutron-gamma field in WWR reactor to neutron fluences of 1·10¹³ and 5·10¹³ n/cm² were provided. The obtained data on the dose dependence of intensity of absorption bands in the visible range allow to identify the origin of optical centers formed under irradiation. Absorption in IR range indicates on the presence in ceramics carbon-related complexes that become active after irradiation. The registered EPR signal of g = (2.0174±0.0005) and width of (46.1±1.5) G which corresponds to HO₂⁻ or O₃⁻ radicals. The dependences of the investigated centers on annealing temperature of the irradiated spinel ceramics show unusual increase in intensity of absorption and steady-state radio-luminescence in the temperature range of 200…400 °C. The role of complexes of defects including anti-site defects in formation and healing of defects in different temperature ranges are analyzed taking into account different mobility of cations and anions and specific mechanism of radio-luminescence.Проведені спектроскопічні дослідження в оптичній кераміці шпінелі, опроміненій гамма-променями джерела ⁶⁰Co та змішаним гамма-нейтронним потоком у ВВР реакторі при потоках нейтронів 1·10¹³ та 5·10¹³ нейтр./см². Одержані дані із залежності інтенсивності смуг поглинання у видимій області дозволили ідентифікувати природу оптичних центрів, створених опромінюванням. Поглинання світла в інфрачервоній області вказує на присутність у кераміці комплексів, що містять вуглець та стають оптично активними після опромінення. Зареєстрований сигнал ЕПР з g = (2.0174 ±0.0005) і шириною (46.1±1.5) Гс, що відповідає HO₂⁻ - або O₃⁻ -радикалам. Залежність досліджених центрів від температури відпалу в опроміненій кераміці шпінелі демонструє незвичайне збільшення інтенсивності поглинання та стаціонарної люмінесценції в інтервалі температур 200…400 °C. Проаналізована роль комплексів дефектів, які включають дефекти антиструктури в створенні та відпалу дефектів у різних температурних областях з урахуванням різної рухливості катіонів та аніонів, а також специфіки механізму рентегнолюмінесценції.Проведены спектроскопические исследования оптической керамики шпинели, облученной гамма-квантами источника ⁶⁰Co и смешанным гамма-нейтронным потоком в реакторе ВВР при потоках нейтронов 1·10¹³ и 5·10¹³ нейтр./см². Полученные данные из зависимости интенсивности полос поглощения в видимой области позволили определить природу оптических центров, созданных облучением. Поглощение света в инфракрасной области указывает на присутствие в керамике углеродсодержащих комплексов, которые становятся оптически активными после облучения. Зарегистрированный сигнал ЭПР с g = (2.0174 ±0.0005) и шириной (46.1±1.5) Гс, соответствующий HO₂⁻ - или O₃⁻ -радикалам. Зависимость концентраций исследованных центров от температуры отжига в облученной керамике шпинели демонстрирует необычный рост интенсивности поглощения и стационарной люминесценции в интервале температур 200…400 °C. Проанализирована роль комплексов дефектов, которые включают дефекты антиструктуры в образовании и отжиге дефектов в различных температурных областях с учетом различной подвижности катионов и анионов, а также специфики механизма рентгенолюминесценции

A systematic review of neurological manifestations of SARS-CoV-2 infection: the devil is hidden in the details

BACKGROUND AND PURPOSE We systematically reviewed available evidence for reports of neurological signs and symptoms in patients with COVID-19 to identify cases with severe acute respiratory syndrome coronavirus (SARS-CoV)-2 infection or immune-mediated reaction in the nervous system. METHODS We followed PRISMA guidelines and used the MEDLINE, EMBASE, Google Scholar, MedRxiv and ChinaXiv databases to search for articles on COVID-19 and nervous system involvement that were published from 1 January to 24 April 2020. Data on design, sample size, neurological assessment and related work-up were extracted. Biases were assessed with the Newcastle-Ottawa scale. RESULTS We analysed 27 publications on potential neuroinvasive or parainfectious neurological complications of COVID-19. The reports focused on smell and taste (n = 5) and evaluation of neurological symptoms and signs in cohorts (n = 5). There were cases of Guillain-Barré syndrome/Miller-Fisher syndrome/cranial neuropathy (seven cases), meningitis/encephalitis (nine cases) and various other conditions (five cases). The number of patients with examination of cerebrospinal fluid and, in particular, SARS-CoV-2 polymerase chain reaction was negligible. Two had a positive SARS-CoV-2 polymerase chain reaction examination of cerebrospinal fluid specimen. Study of potential parenchymal involvement with magnetic resonance imaging was rare. Only four reports received a rating of the highest quality standards. CONCLUSIONS This systematic review failed to establish comprehensive insights into nervous system manifestations of COVID-19 beyond immune-mediated complications in the aftermath of respiratory symptoms. The authors therefore provide guidance for more careful clinical, diagnostic and epidemiological studies to characterize the manifestations and burden of neurological disease caused by SARS-CoV-2 on behalf of the Infectious Disease Panel of the European Academy of Neurology

"Комп'ютерне моделювання і керування в техніці та технологіях КМКТТ-2021", Дев’ята міжнародна науково-практична конференція

Nowadays we need the ability to receive information from different sources, use it and create it independently. Practical use of information and communication technologies provide new teaching opportunities, greatly facilitate the work of teachers, increase the effectiveness of teaching process, improve the quality of teaching.В современном мире нам нужна возможность получать информацию из разных источников, использовать ее и создавать самостоятельно. Практическое использование информационных и коммуникационных технологий открывает новые возможности обучения, значительно облегчает работу учителей, повышает эффективность учебного процесса, улучшает качество обучения

MRS changes in CADASIL: preliminary results

Objectives: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an autosomal dominant disorder characterized by ischemic episodes, cognitive impairment, and migraine, often with aura. Cerebral MRI reveals signal hyperintensities in the white matter, especially of the temporal lobes. We investigated CADASIL patients with 1H-magnetic resonance spectroscopy (MRS) for different cerebral metabolites, namely N-acetylaspartate (NAA), creatine, choline, myoinositole (MI), and lactate. Methods: To date, we studied 4 CADASIL patients and 4 healthy controls. CADASIL diagnosis was confirmed by skin biopsy and/or genetic analysis. MRS was performed on a 3T Philips MR system. 1H-MRS data were acquired using high resolution multi-spin echo spectroscopic imaging (TSI; TE=288ms, slice thickness =1.5cm, resolution 28x28, FOV=320mm) and conventional chemical shift imaging (CSI; TE=35 ms, resolution 16x16 and TE=288ms, resolution 12x12, slice thickness=2cm, FOV=320mm). Bandwidth was 2500 Hz and repetition time 1520 for all measurements. CSI measurements with TE=288 ms were repeated 6 times consecutively. The 1st and the last two measurements were performed in darkness, in the others visual stimulation with a stroboscope (8 Hz) was applied. Data were obtained from a transversal slice adjusted parallel to the calcarine fissure, including the visual cortex. In addition, we performed single voxel (SV) MRS of the temporal pole. Results: All CADASIL patients showed characteristic MRI findings including the temporal lobe. NAA/creatine ratios were decreased in all patients, most markedly in temporal lobes and periventricular areas. Choline/creatine ratios were unchanged and no myoinositole was detected. Voxels adjacent to the calcarine fissure showed elevated lactate peaks at baseline in 2 patients without change during visual stimulation. Conclusion: NAA/creatine ratios were diminished in all CADASIL patients in areas with visible lesions. Decreased NAA/creatine ratios might therefore be used as an additional, possibly more sensitive marker of neuronal damage in CADASIL. Specificity and sensitivity of NAA alterations as well as the significance of lactate changes will be further evaluted in our ongoing study

Lactate in the healthy brain

The development of 1H Magnetic Resonance Spectroscopy (MRS) techniques has made it possible to detect different brain metabolites, including elevated lactate concentrations in vivo in humans. It is generally assumed that increased brain lactate is pathological and reflects a dysbalance between glycolysis and oxidative respiration. However, there is an alternative opinion, suggesting that elevated lactate concentration in the brain represents a normal response to neuronal activity. Visual stimulation is one of the functional paradigms that can modify brain lactate levels. We performed 1H MRS (chemical shift imaging at TE of 35ms and 288 ms) with a Philips Achieva 3T MRI scanner in 19 healthy volunteers without any history of neurological or psychiatric disorders. MRS measurements have been performed before, during and after light stimulation. Using an optimized protocol, lactate was detected in three probands (15.8\%). In one case lactate emerged as a result of the stimulation, while two others showed lactate at baseline. One of the probands had a high lactate double peak in the absence of previous physical or psychological strain; this finding was not reproduced in two follow-up 1H-MRS measurements. Our findings demonstrate that detectable levels of lactate may be present in healthy brains, and show considerable variability without any known pathology or exercise prior to the measurement. Thus, the interpretation of elevated brain lactate levels in neurological and psychiatric disorders has to be done with caution

Neurological side effects and drug interactions of antiviral compounds against SARS-CoV-2.

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), rapidly spread across the globe. Tremendous efforts have been mobilized to create effective antiviral treatment options to reduce the burden of the disease. This article summarizes the available knowledge about the antiviral drugs against SARS-CoV-2 from a neurologist's perspective. We summarize neurological aspects of antiviral compounds against SARS-CoV-2 with full, conditional, or previous marketing authorization by the European Medicines Agency (EMA). Nirmatrelvir/ritonavir targets the SARS-CoV-2 3c-like protease using combinatorial chemistry. Nirmatrelvir/ritonavir levels are affected by medications metabolized by or inducing CYP3A4, including those used in neurological diseases. Dysgeusia with a bitter or metallic taste is a common side effect of nirmatrelvir/ritonavir. Molnupiravir is a nucleotide analog developed to inhibit the replication of viruses. No clinically significant interactions with other drugs have been identified, and no specific considerations for people with neurological comorbidity are required. In the meantime, inconsistent results from clinical trials regarding efficacy have led to the withdrawal of marketing authorization by the EMA. Remdesivir is a viral RNA polymerase inhibitor and interferes with the production of viral RNA. The most common side effect in patients with COVID-19 is nausea. Remdesivir is a substrate for CYP3A4. Neurological side effects and drug interactions must be considered for antiviral compounds against SARS-CoV-2. Further studies are required to better evaluate their efficacy and adverse events in patients with concomitant neurological diseases. Moreover, evidence from real-world studies will complement the current knowledge