23 research outputs found
Recommended from our members
Experimental study of diurnal and seasonal variations in the atmospheric electric field
In order to separate global and local effects of atmospheric electricity, measurements of the fair-weather electric field were performed in Nizhny Novgorod in 2013-2018. As a result of processing 139 diurnal records from four observation points spaced 6–8 km apart, diurnal variations in the fair-weather atmospheric electric field for different seasons and weekdays (working days and weekends) were studied. The curve of the local diurnal variation is shown to always have two maxima. The evening maximum of the diurnal variation (19:00–20:00 UT) coincides in time with the maximum of the Carnegie curve, which is a characteristic of the global electrical circuit. The highest values of the field amplitude are reached in the winter period. The field-intensity maximum in the first half of the day (09:00–11:00 LT) is characteristic of the urban environment and shows that local effects associated with the presence of aerosol particles in the air significantly contribute to the formation of diurnal variation, especially in summer. According to the 2013–2018 measurements, the seasonal variation in the monthly-average values of the atmospheric electric field is revealed and analyzed compared with the results of measurements of seasonal variation in other regions of the globe. The obtained results allow one to reveal the role of local effects in the formation of diurnal variation in the mid-latitude areas with temperate continental climate and provide a basis for developing a theory which can explain the physical mechanisms of local effects and suggest appropriate parametrization for finding the surface electric field in the weather and climate models
Synaptic terminal density early in the course of schizophrenia: an in vivo UCB-J positron emission tomographic imaging study of synaptic vesicle glycoprotein 2A (SV2a).
BACKGROUND: The synaptic hypothesis is an influential theory of the pathoaetiology of schizophrenia. Supporting this, there is lower uptake of the synaptic terminal density marker UCB-J in patients with chronic schizophrenia compared to controls. However, it is unclear whether these differences are present early in the illness. To address this, we investigated [11C]UCB-J volume of distribution (VT) in antipsychotic-naïve/free patients with schizophrenia (SCZ) recruited from first-episode services compared to healthy volunteers (HV). METHODS: Forty-two volunteers (SCZ n = 21, HV n = 21) underwent [11C]UCB-J positron emission tomography to index [11C]UCB-J VT and distribution volume ratio (DVR) in the anterior cingulate, frontal, and dorsolateral prefrontal cortices, temporal, parietal and occipital lobes, hippocampus, thalamus and amygdala. Symptom severity was assessed in the SCZ group using the Positive and Negative Syndrome Scale (PANSS). RESULTS: We found no significant effects of group on [11C]UCB-J VT or DVR in most regions of interest (effect sizes from d=0.0 to 0.7, p>0.05), other than lower DVR in the temporal lobe (d=0.7, uncorrected p<0.05) and lower VT/fp in the anterior cingulate cortex in patients (d=0.7, uncorrected p<0.05). PANSS total score was negatively associated with [11C]UCB-J VT in the hippocampus in the SCZ group (r =-0.48, p=0.03). CONCLUSIONS: These findings indicate that large differences in synaptic terminal density are not present early in schizophrenia, although there may be more subtle effects. When taken with prior evidence of lower [11C]UCB-J VT in patients with chronic illness, this may indicate synaptic density changes during the course of schizophrenia
ASSOCIATIONS OF POLYMORPHISMS IN CYTOKINE GENES WITH THE INFECTIOUS GENESIS Of RECCURENT MISCARRIAGE
The associations of polymorphisms in cytokine genes with the infectious form recurrent miscarriage were investigated. Have established, that at the women a genotype AA of a gene TNFA (rs1800629) and combination of genotypes *1/*1 genes IL1RN and GG of a gene IL6 (rs1800795) are involved in pathogenesis recurrent miscarriage
An analysis-ready and quality controlled resource for pediatric brain white-matter research
We created a set of resources to enable research based on openly-available diffusion MRI (dMRI) data from the Healthy Brain Network (HBN) study. First, we curated the HBN dMRI data (N = 2747) into the Brain Imaging Data Structure and preprocessed it according to best-practices, including denoising and correcting for motion effects, susceptibility-related distortions, and eddy currents. Preprocessed, analysis-ready data was made openly available. Data quality plays a key role in the analysis of dMRI. To optimize QC and scale it to this large dataset, we trained a neural network through the combination of a small data subset scored by experts and a larger set scored by community scientists. The network performs QC highly concordant with that of experts on a held out set (ROC-AUC = 0.947). A further analysis of the neural network demonstrates that it relies on image features with relevance to QC. Altogether, this work both delivers resources to advance transdiagnostic research in brain connectivity and pediatric mental health, and establishes a novel paradigm for automated QC of large datasets
Neuroimaging in schizophrenia: an overview of findings and their implications for synaptic changes.
Over the last five decades, a large body of evidence has accrued for structural and metabolic brain alterations in schizophrenia. Here we provide an overview of these findings, focusing on measures that have traditionally been thought to reflect synaptic spine density or synaptic activity and that are relevant for understanding if there is lower synaptic density in the disorder. We conducted literature searches to identify meta-analyses or other relevant studies in patients with chronic or first-episode schizophrenia, or in people at high genetic or clinical risk for psychosis. We identified 18 meta-analyses including over 50,000 subjects in total, covering: structural MRI measures of gyrification index, grey matter volume, grey matter density and cortical thickness, neurite orientation dispersion and density imaging, PET imaging of regional glucose metabolism and magnetic resonance spectroscopy measures of N-acetylaspartate. We also review preclinical evidence on the relationship between ex vivo synaptic measures and structural MRI imaging, and PET imaging of synaptic protein 2A (SV2A). These studies show that schizophrenia is associated with lower grey matter volumes and cortical thickness, accelerated grey matter loss over time, abnormal gyrification patterns, and lower regional SV2A levels and metabolic markers in comparison to controls (effect sizes from ~ -0.11 to -1.0). Key regions affected include frontal, anterior cingulate and temporal cortices and the hippocampi. We identify several limitations for the interpretation of these findings in terms of understanding synaptic alterations. Nevertheless, taken with post-mortem findings, they suggest that schizophrenia is associated with lower synaptic density in some brain regions. However, there are several gaps in evidence, in particular whether SV2A findings generalise to other cohorts