223 research outputs found
The use of WEB 2.0 services for teacher
The article discusses the possibility of using web 2.0 services in the work of the teacher, on the examples of social networks, blog and designer to create testsВ статье рассматривается возможность использования сервисов веб 2.0 в работе преподавателя на примерах социальных сетей, блога и конструктора для создания тесто
Metal-insulator transition induced by 16O -18O oxygen isotope exchange in colossal negative magnetoresistance manganites
The effect of 16O-18O isotope exchange on the electric resistivity was
studied for (La(1-y)Pr(y))0.7Ca0.3MnO3 ceramic samples. Depending on y, this
mixed perovskite exhibited different types of low-temperature behavior ranging
from ferromagnetic metal (FM) to charge ordered (CO) antiferromagnetic
insulator. It was found that at y=0.75, the substitution of 16O by 18O results
in the reversible transition from a FM to a CO insulator at zero magnetic
field. The applied magnetic field (H >= 2 T) transformed the sample with 18O
again to the metallic state and caused the increase in the FM transition
temperature Tc of the 16O sample. As a result, the isotope shift of Tc at H = 2
T was as high as 63 K. Such unique sensitivity of the system to oxygen isotope
exchange, giving rise even to the metal-insulator transition, is discussed in
terms of the isotope dependence of the effective electron bandwidth which
shifts the balance between the CO and FM phases.Comment: 5 pages (RevTeX), 2 eps figures included, to appear in J. Appl. Phys.
83, (1998
PHYSICOCHEMICAL CHARACTERIZATION OF RIBAVIRIN WITH SPECTROSCOPY AND MOLECULAR MODELING
This work was supported by Mendeleev University of Chemical Technology of Russia. Project Number K-003-2018
MPTP-Treated Zebrafish Recapitulate ‘Late-Stage’ Parkinson’s-like Cognitive Decline
The zebrafish is a promising model species in biomedical research, including neurotoxicology and neuroactive drug screening. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) evokes degeneration of dopaminergic neurons and is commonly used to model Parkinson’s disease (PD) in laboratory animals, including zebrafish. However, cognitive phenotypes in MPTP-evoked experimental PD models remain poorly understood. Here, we established an LD50 (292 mg/kg) for intraperitoneal MPTP administration in adult zebrafish, and report impaired spatial working memory (poorer spontaneous alternation in the Y-maze) in a PD model utilizing fish treated with 200 µg of this agent. In addition to conventional behavioral analyses, we also employed artificial intelligence (AI)-based approaches to independently and without bias characterize MPTP effects on zebrafish behavior during the Y-maze test. These analyses yielded a distinct cluster for 200-µg MPTP (vs. other) groups, suggesting that high-dose MPTP produced distinct, computationally detectable patterns of zebrafish swimming. Collectively, these findings support MPTP treatment in adult zebrafish as a late-stage experimental PD model with overt cognitive phenotypes. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Funding: The experiments were implemented using the equipment and unique scientific installation “Biological collection–Genetic biomodels of neuropsychiatric disorders” (No. 493387) of the Federal State Budgetary Scientific Institution “Scientific Research Institute of Neurosciences and Medicine” theme no. AAAA-A21-121011990039-2 (2021–2025). The study partially used the facilities and equipment of the Resource Fund of Applied Genetics MIPT (support grant 075-15-2021-684)
Novel internal measurements of ion cyclotron frequency range fast-ion driven modes
Novel internal measurements and analysis of ion cyclotron frequency range fast-ion driven modes in DIII-D are presented. Observations, including internal density fluctuation (˜n) measurements obtained via Doppler backscattering, are presented for modes at low harmonics of the ion cyclotron frequency localized in the edge. The measurements indicate that these waves, identified as coherent ion cyclotron emission (ICE), have high wave number, k⊥ρfast1, consistent with the cyclotron harmonic wave branch of the magnetoacoustic cyclotron instability, or electrostatic instability mechanisms. Measurements show extended spatial structure (at least ∼1/6 the minor radius). These edge ICE modes undergo amplitude modulation correlated with edge localized modes (ELM) that is qualitatively consistent with expectations for ELM-induced fast-ion transport
THE PREVENTION, DIAGNOSIS, AND TREATMENT OF VITAMIN D AND CALCIUM DEFICIENCIES IN THE ADULT POPULATION OF RUSSIA AND IN PATIENTS WITH OSTEOPOROSIS (ACCORDING TO THE MATERIALS OF PREPARED CLINICAL RECOMMENDATIONS)
The paper presents data on the role of vitamin D and calcium in the function of many human organs and tissues. Lifestyle, dietary preferences, and insufficient physical activity contribute to the high prevalence of vitamin D and calcium deficiencies in the adult population of Russia, causing different diseases and abnormalities. The authors have worked out recommendations for the preventive use of vitamin D and calcium in healthy population, give consumption rates for these substances, and describe the clinical and laboratory signs of vitamin D deficiency and indications for screening. They also propose treatment regimens for vitamin D deficiency and depict the signs of intoxication inoverdose. Particular emphasis is laid on the place of vitamin D and calcium in the therapy of osteoporosis
A DNA Sequence Directed Mutual Transcription Regulation of HSF1 and NFIX Involves Novel Heat Sensitive Protein Interactions
BACKGROUND: Though the Nuclear factor 1 family member NFIX has been strongly implicated in PDGFB-induced glioblastoma, its molecular mechanisms of action remain unknown. HSF1, a heat shock-related transcription factor is also a powerful modifier of carcinogenesis by several factors, including PDGFB. How HSF1 transcription is controlled has remained largely elusive. METHODOLOGY/PRINCIPAL FINDINGS: By combining microarray expression profiling and a yeast-two-hybrid screen, we identified that NFIX and its interactions with CGGBP1 and HMGN1 regulate expression of HSF1. We found that CGGBP1 organizes a bifunctional transcriptional complex at small CGG repeats in the HSF1 promoter. Under chronic heat shock, NFIX uses CGGBP1 and HMGN1 to get recruited to this promoter and in turn affects their binding to DNA. Results show that the interactions of NFIX with CGGBP1 and HMGN1 in the soluble fraction are heat shock sensitive due to preferential localization of CGGBP1 to heterochromatin after heat shock. HSF1 in turn was found to bind to the NFIX promoter and repress its expression in a heat shock sensitive manner. CONCLUSIONS/SIGNIFICANCE: NFIX and HSF1 exert a mutual transcriptional repressive effect on each other which requires CGG repeat in HSF1 promoter and HSF1 binding site in NFIX promoter. We unravel a unique mechanism of heat shock sensitive DNA sequence-directed reciprocal transcriptional regulation between NFIX and HSF1. Our findings provide new insights into mechanisms of transcription regulation under stress
Heart Rate Variability Dynamics for the Prognosis of Cardiovascular Risk
Statistical, spectral, multi-resolution and non-linear methods were applied to heart rate variability (HRV) series linked with classification schemes for the prognosis of cardiovascular risk. A total of 90 HRV records were analyzed: 45 from healthy subjects and 45 from cardiovascular risk patients. A total of 52 features from all the analysis methods were evaluated using standard two-sample Kolmogorov-Smirnov test (KS-test). The results of the statistical procedure provided input to multi-layer perceptron (MLP) neural networks, radial basis function (RBF) neural networks and support vector machines (SVM) for data classification. These schemes showed high performances with both training and test sets and many combinations of features (with a maximum accuracy of 96.67%). Additionally, there was a strong consideration for breathing frequency as a relevant feature in the HRV analysis
Heart Rate Variability Dynamics for the Prognosis of Cardiovascular Risk
Statistical, spectral, multi-resolution and non-linear methods were applied to heart rate variability (HRV) series linked with classification schemes for the prognosis of cardiovascular risk. A total of 90 HRV records were analyzed: 45 from healthy subjects and 45 from cardiovascular risk patients. A total of 52 features from all the analysis methods were evaluated using standard two-sample Kolmogorov-Smirnov test (KS-test). The results of the statistical procedure provided input to multi-layer perceptron (MLP) neural networks, radial basis function (RBF) neural networks and support vector machines (SVM) for data classification. These schemes showed high performances with both training and test sets and many combinations of features (with a maximum accuracy of 96.67%). Additionally, there was a strong consideration for breathing frequency as a relevant feature in the HRV analysis
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