269 research outputs found

    Nanodiamond landmarks for subcellular multimodal optical and electron imaging.

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    There is a growing need for biolabels that can be used in both optical and electron microscopies, are non-cytotoxic, and do not photobleach. Such biolabels could enable targeted nanoscale imaging of sub-cellular structures, and help to establish correlations between conjugation-delivered biomolecules and function. Here we demonstrate a sub-cellular multi-modal imaging methodology that enables localization of inert particulate probes, consisting of nanodiamonds having fluorescent nitrogen-vacancy centers. These are functionalized to target specific structures, and are observable by both optical and electron microscopies. Nanodiamonds targeted to the nuclear pore complex are rapidly localized in electron-microscopy diffraction mode to enable "zooming-in" to regions of interest for detailed structural investigations. Optical microscopies reveal nanodiamonds for in-vitro tracking or uptake-confirmation. The approach is general, works down to the single nanodiamond level, and can leverage the unique capabilities of nanodiamonds, such as biocompatibility, sensitive magnetometry, and gene and drug delivery

    Iron charge state distributions as an indicator of hot ICMEs: Possible sources and temporal and spatial variations during solar maximum

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95224/1/jgra17034.pd

    Introduction to Old Javanese Language and Literature

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    The oldest and most extensive written language of Southeast Asia is Old Javanese, or Kawi. It is the oldest language in terms of written records, and the most extensive in the number and variety of its texts. Javanese literature has taken many forms. At various times, prose stories, sung poetry or other metrical types, chronicles, scientific, legal, and philosophical treatises, prayers, chants, songs, and folklore were all written down. Yet relatively few texts are available in English. The unstudied texts remaining are an unexplored record of Javanese culture as well as a language still alive as a literary medium in Bali. Introduction to Old Javanese Language and Literature represents a first step toward remedying the dearth of Old Javanese texts available to English-speaking students. The ideal teaching companion, this anthology offers transliterated original texts with facing-page English translations. Theanthology focuses on prose selections, since their straightforward style and syntax offer the beginning student the most rewarding experience. Four sections make up the collection. Part I offers several short readings as the most accessible entry point into Old Javanese. Part II contains two moralistic fables from an Old Javanese retelling of the Hindu Pañcatantra cycle. Part III takes up the epic, providing excerpts from one of the books of the Old Javanese retelling of the Mahabharata. Part IV offers excerpts from two chronicles, the generic conventions of which challenge received notions of history writing because of their supernaturalism and folkloric elements. Includes introduction, glossary, and notes

    Variations in solar wind fractionation as seen by ACE/SWICS over a solar cycle and the implications for Genesis Mission results

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    We use ACE/SWICS elemental composition data to compare the variations in solar wind fractionation as measured by SWICS during the last solar maximum (1999-2001), the solar minimum (2006-2009) and the period in which the Genesis spacecraft was collecting solar wind (late 2001 - early 2004). We differentiate our analysis in terms of solar wind regimes (i.e. originating from interstream or coronal hole flows, or coronal mass ejecta). Abundances are normalized to the low-FIP ion magnesium to uncover correlations that are not apparent when normalizing to high-FIP ions. We find that relative to magnesium, the other low-FIP elements are measurably fractionated, but the degree of fractionation does not vary significantly over the solar cycle. For the high-FIP ions, variation in fractionation over the solar cycle is significant: greatest for Ne/Mg and C/Mg, less so for O/Mg, and the least for He/Mg. When abundance ratios are examined as a function of solar wind speed, we find a strong correlation, with the remarkable observation that the degree of fractionation follows a mass-dependent trend. We discuss the implications for correcting the Genesis sample return results to photospheric abundances.Comment: Accepted for publication in Ap

    The new heliospheric magnetic field: Observational implications

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    A summary of the new model of the heliospheric magnetic field and its observational implications is presented. We first introduce a global model for the steady-state configuration in the low corona and discuss solar and heliospheric implications of the resulting field configuration. Finally, we compare the effects of this model with random transport of field-lines due to reconnection on the solar surface and to the dynamic turbulent transport of magnetic field-lines. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87723/2/87_1.pd

    Energy Harvesting from the Beating Heart by a Mass Imbalance Oscillation Generator

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    Energy-harvesting devices attract wide interest as power supplies of today's medical implants. Their long lifetime will spare patients from repeated surgical interventions. They also offer the opportunity to further miniaturize existing implants such as pacemakers, defibrillators or recorders of bio signals. A mass imbalance oscillation generator, which consists of a clockwork from a commercially available automatic wrist watch, was used as energy harvesting device to convert the kinetic energy from the cardiac wall motion to electrical energy. An MRI-based motion analysis of the left ventricle revealed basal regions to be energetically most favorable for the rotating unbalance of our harvester. A mathematical model was developed as a tool for optimizing the device's configuration. The model was validated by an in vitro experiment where an arm robot accelerated the harvesting device by reproducing the cardiac motion. Furthermore, in an in vivo experiment, the device was affixed onto a sheep heart for 1h. The generated power in both experiments—in vitro (30μW) and in vivo (16.7μW)—is sufficient to power modern pacemaker

    Numerical Simulations of Helicity Condensation in the Solar Corona

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    The helicity condensation model has been proposed by Antiochos (2013) to explain the observed smoothness of coronal loops and the observed buildup of magnetic shear at filament channels. The basic hypothesis of the model is that magnetic reconnection in the corona causes the magnetic stress injected by photospheric motions to collect only at those special locations where prominences form. In this work we present the first detailed quantitative MHD simulations of the reconnection evolution proposed by the helicity condensation model. We use the well-known ansatz of modeling the closed corona as an initially uniform field between two horizontal photospheric plates. The system is driven by applying photospheric rotational flows that inject magnetic helicity into the system. The flows are confined to a finite region on the photosphere so as to mimic the finite flux system of, for example, a bipolar active region. The calculations demonstrate that, contrary to common belief, coronal loops having opposite helicity do not reconnect, whereas loops having the same sense of helicity do reconnect. Furthermore, we find that for a given amount of helicity injected into the corona, the evolution of the magnetic shear is insensitive to whether the pattern of driving photospheric motions is fixed or quasi-random. In all cases, the shear propagates via reconnection to the boundary of the flow region while the total magnetic helicity is conserved, as predicted by the model. We discuss the implications of our results for solar observations and for future, more realistic simulations of the helicity condensation process
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