1,892 research outputs found

    Content of radioactive elements of the small mammal biological material in the anthropogenic impact zones and background areas

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    В данной статье рассматриваются особенности содержания химических элементов урана (U), и тория (Th), изученные методом инструментального нейтронно-активационного анализа, в пробах эмбриона, плаценты и печени мелкого млекопитающего вида Полевка рыжая (Myodes glareolus), отобранных около крупного медеплавильного завода (г. Ревда, Свердловская область). As the title implies the article describes a specific of content of chemical elements uranium (U), and thorium (Th), studied with Instrumental neutron-activation analysis in samples of embryo, placenta and liver of small mammal species Vole red (Myodes glareolus), sampled near large copper-smelting plant (Revda, Sverdlovsk region)

    High-Resolution Optical Functional Mapping of the Human Somatosensory Cortex

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    Non-invasive optical imaging of brain function has been promoted in a number of fields in which functional magnetic resonance imaging (fMRI) is limited due to constraints induced by the scanning environment. Beyond physiological and psychological research, bedside monitoring and neurorehabilitation may be relevant clinical applications that are yet little explored. A major obstacle to advocate the tool in clinical research is insufficient spatial resolution. Based on a multi-distance high-density optical imaging setup, we here demonstrate a dramatic increase in sensitivity of the method. We show that optical imaging allows for the differentiation between activations of single finger representations in the primary somatosensory cortex (SI). Methodologically our findings confirm results in a pioneering study by Zeff et al. (2007) and extend them to the homuncular organization of SI. After performing a motor task, eight subjects underwent vibrotactile stimulation of the little finger and the thumb. We used a high-density diffuse-optical sensing array in conjunction with optical tomographic reconstruction. Optical imaging disclosed three discrete activation foci one for motor and two discrete foci for vibrotactile stimulation of the first and fifth finger, respectively. The results were co-registered to the individual anatomical brain anatomy (MRI) which confirmed the localization in the expected cortical gyri in four subjects. This advance in spatial resolution opens new perspectives to apply optical imaging in the research on plasticity notably in patients undergoing neurorehabilitation

    Analysis of charge and orbital order in Fe_{3}O_{4} by Fe L_{2,3} resonant x-ray diffraction

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    To elucidate charge and orbital order below the Verwey transition temperature TV∼125 K, a thin layer of magnetite partially detwined by growth on the stepped MgO(001) substrate has been studied by means of soft x-ray diffraction at the Fe L2,3 resonance. The azimuth angle, incident photon polarization, and energy dependence of the (0012)c and (001)c reflection intensities have been measured, and analyzed using a configuration-interaction FeO6 cluster model. The azimuth dependence of the (0012)c reflection intensities directly represents the space-group symmetry of the orbital order in the initial state rather than indirectly through the intermediate-state level shifts caused by the order-induced lattice distortions. From the analysis of the (0012)c reflection intensities, the orbital order in the t2g orbitals of B sites below TV is proved to have a large monoclinic deformation with the value of Re[Fxy]/Re[Fyz]∼2. This finding contradicts the majority of theories on the Verwey transition so far proposed. We show that the experimentally observed resonance spectra cannot be explained by orbital and charge orders obtained with recent LDA+U and GGA+U band structure calculations but by a complex- number orbital order with excellent agreement

    No ecological opportunity signal on a continental scale?:Diversification and life-history evolution of african true toads (Anura: Bufonidae)

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    The niche-filling process predicted by the “ecological opportunity” (EO) model is an often-invoked mechanism for generating exceptional diversity in island colonizers. Whether the same process governs lineage accumulation and trait disparity during continental colonization events is less clear. Here, we test this prediction by investigating the rate dynamics and trait evolution of one of Africa's most widespread amphibian colonizers, the true toads (Bufonidae). By reconstructing the most complete molecular phylogeny of African Bufonidae to date, we find that the diversification of lineages in Africa best conforms to a constant rate model throughout time and across subclades, with little support for EO. Evolutionary rates of life-history traits have similarly been constant over time. However, an analysis of generalists and specialists showed a shift toward higher speciation rates associated with habitat specialization. The overall lack of EO signal can be interpreted in a number of ways and we propose several explanations. Firstly, methodological issues might preclude the detection of EO. Secondly, colonizers might not experience true EO conditions and due to the size, ecological heterogeneity and age of landmasses, the diversification processes might be more complex. Thirdly, lower speciation rates of habitat generalists may have affected overall proliferation of lineages

    No Evidence of Persisting Unrepaired Nuclear DNA Single Strand Breaks in Distinct Types of Cells in the Brain, Kidney, and Liver of Adult Mice after Continuous Eight-Week 50 Hz Magnetic Field Exposure with Flux Density of 0.1 mT or 1.0 mT

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    BACKGROUND: It has been hypothesized in the literature that exposure to extremely low frequency electromagnetic fields (50 or 60 Hz) may lead to human health effects such as childhood leukemia or brain tumors. In a previous study investigating multiple types of cells from brain and kidney of the mouse (Acta Neuropathologica 2004; 107: 257-264), we found increased unrepaired nuclear DNA single strand breaks (nDNA SSB) only in epithelial cells of the choroid plexus in the brain using autoradiographic methods after a continuous eight-week 50 Hz magnetic field (MF) exposure of adult mice with flux density of 1.5 mT. METHODS: In the present study we tested the hypothesis that MF exposure with lower flux densities (0.1 mT, i.e., the actual exposure limit for the population in most European countries, and 1.0 mT) shows similar results to those in the previous study. Experiments and data analysis were carried out in a similar way as in our previous study. RESULTS: Continuous eight-week 50 Hz MF exposure with 0.1 mT or 1.0 mT did not result in increased persisting unrepaired nDNA SSB in distinct types of cells in the brain, kidney, and liver of adult mice. MF exposure with 1.0 mT led to reduced unscheduled DNA synthesis (UDS) in epithelial cells in the choroid plexus of the fourth ventricle in the brain (EC-CP) and epithelial cells of the cortical collecting duct in the kidney, as well as to reduced mtDNA synthesis in neurons of the caudate nucleus in the brain and in EC-CP. CONCLUSION: No evidence was found for increased persisting unrepaired nDNA SSB in distinct types of cells in the brain, kidney, and liver of adult mice after continuous eight-week 50 Hz magnetic field exposure with flux density of 0.1 mT or 1.0 mT

    Динамические тенденции в становлении предмета лингвоэкологии

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    Экологизация всех сфер общественной жизни и самого человека широко обсуждается во многих наука, а также и в области языка. Во многих работах лингвистов экология языка определяется как наука о взаимоотношениях между языком и его окружением, так как язык существует не только в сознании говорящих на нем и функционирует только при взаимоотношениях с другими коммуникантами и с их социальным и природным окружением. В этом контексте понятие «языковое сознание» представляет собой специфическую картину взаимосвязи культуры и общественной жизни социума, которая определяет его психологическое своеобразие и специфические черты данного языка

    Detection of Peptide-Based Nanoparticles in Blood Plasma by ELISA

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    Aims The aim of the current study was to develop a method to detect peptide-linked nanoparticles in blood plasma. Materials & Methods A convenient enzyme linked immunosorbent assay (ELISA) was developed for the detection of peptides functionalized with biotin and fluorescein groups. As a proof of principle, polymerized pentafluorophenyl methacrylate nanoparticles linked to biotin-carboxyfluorescein labeled peptides were intravenously injected in Wistar rats. Serial blood plasma samples were analyzed by ELISA and by liquid chromatography mass spectrometry (LC/MS) technology. Results The ELISA based method for the detection of FITC labeled peptides had a detection limit of 1 ng/mL. We were able to accurately measure peptides bound to pentafluorophenyl methacrylate nanoparticles in blood plasma of rats, and similar results were obtained by LC/MS. Conclusions We detected FITC-labeled peptides on pentafluorophenyl methacrylate nanoparticles after injection in vivo. This method can be extended to detect nanoparticles with different chemical compositions
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