471 research outputs found
Development of the consistent second-order plate theory for transversely isotropic plates and its analytical assessment from the three-dimensional perspective
Financial support of this research by The Royal Society (UK) International Exchanges award (IE161021) and by the German Science Foundation (DFG) under Project-No. Ki 284/25-1 is gratefully acknowledgedPeer reviewedPostprin
Solar Wind Sputtering of Lunar Surface Materials: Role and Some Possible Implications of Potential Sputtering
Solar-wind induced sputtering of the lunar surface includes, in principle, both kinetic and potential sputtering. The role of the latter mechanism, however, in many focused studies has not been properly ascertained due partly to lack of data but can also be attributed to the assertion that the contribution of solar-wind heavy ions to the total sputtering is quite low due to their low number density compared to solar-wind protons. Limited laboratory measurements show marked enhancements in the sputter yields of slow-moving, highly-charged ions impacting oxides. Lunar surface sputtering yields are important as they affect, e.g., estimates of the compositional changes in the lunar surface, its erosion rate, as well as its contribution to the exosphere as well as estimates of hydrogen and water contents. Since the typical range of solar-wind ions at ~1 keV/amu is comparable to the thickness of the amorphous rim found on lunar soil grains, i.e. ~ few 10s nm, lunar simulant samples JSC-1A AGGL are specifically enhanced to have such rims in addition to the other known characteristics of the actual lunar soil particles. However, most, if not all laboratory studies of potential sputtering were carried out in single crystal targets, quite different from the rim s amorphous structure. The effect of this structural difference on the extent of potential sputtering has not, to our knowledge, been investigated to date
A Closer Look at Solar Wind Sputtering of Lunar Surface Materials
Solar-wind induced potential sputtering of the lunar surface may be a more efficient erosive mechanism than the "standard" kinetic (or physical) sputtering. This is partly based on new but limited laboratory measurements which show marked enhancements in the sputter yields of slow-moving, highly-charged ions impacting oxides. The enhancements seen in the laboratory can be orders of magnitude for some surfaces and highly charged incident ions, but seem to depend very sensitively on the properties of the impacted surface in addition to the fluence, energy and charge of the impacting ion. For oxides, potential sputtering yields are markedly enhanced and sputtered species, especially hydrogen and light ions, show marked dependence on both charge and dose
COSTEP: A comprehensive suprathermal and energetic particle analyzer for SOHO
The group of instruments involved in the COSTEP (comprehensive suprathermal and energetic particle analyzer) project are described. Three sensors, the LION (low energy ion and electron) instrument, the MEICA (medium energy ion composition analyzer) and the EPHIN (electron proton helium instrument) are described. They are designed to analyze particle emissions from the sun over a wide range of species (electrons through iron) and energies (60 KeV/particle to 500 MeV/nucleon). The data collected is used in studying solar and space plasma physics
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Loss of CCR7 Expression on NK Cells Is Associated with a NK Cell-Like Phenotype and Correlates with HIV Viral Load
NK cells are pivotal sentinels of the innate immune system and distinct subpopulations in peripheral blood have been described. A number of studies addressed HIV-induced alterations of NK cell phenotype and functionality mainly focusing on and NK cells. However, the impact of HIV-infection on NK cells is less well understood. Here we report a rise of NK cells in HIV-infected individuals, which lack CCR7-expression and strongly correlate with HIV viral load. NK cells were characterized by increased cytolytic potential, higher activation states and a more differentiated phenotype. These cells thus acquired a number of features of NK cells. Furthermore, NK cells from HIV patients exhibited higher degranulation levels compared to uninfected individuals. Thus, chronic HIV-infection is associated with a phenotypic and functional shift of NK cells, which provides a novel aspect of HIV-associated pathogenesis within the NK cell compartment
The Interplay of People and Technologies
Histories of innovation are prototypical success
stories. The advent of the wheel, of writing, printing,
the steam engine or computers: where would we be
without these path-breaking technological innovations
and their global consequences? At least retrospectively,
innovations appear as linear, straightforward processes.
However, this view is too simplistic. Innovations are not
self-evident new elements of life but meet social and
technological resistance. In accounts of past innovations,
we also often forget that their price is always an
irremediable loss of knowledge and practical skills.
This collection of essays shows that innovations, both
ancient and more recent ones, are located in a network
of pre-existing life-worlds. The authors elucidate the
wide and often unrecognized impacts of innovations
on social structures and cultural practices. Case studies
from ancient Mesopotamia, Egypt, central Europe
and the modern world highlight the preconditions
and off-ignored secondary effects of innovation.
They address the complex social negotiations and
the multitude of unforeseen and unplanned changes
which accompany the New, rather than focusing on
intended changes, which are usually understood as
improvements and ways to broaden possibilities for
action. Our ultimate goal is to investigate the complex
entangle ments of innovations in past and present
worlds and deepen our understanding of mechanisms
of cultural change
Quantum phase retrieval of a Rydberg wave packet using a half-cycle pulse
A terahertz half-cycle pulse was used to retrieve information stored as
quantum phase in an -state Rydberg atom data register. The register was
prepared as a wave packet with one state phase-reversed from the others (the
"marked bit"). A half-cycle pulse then drove a significant portion of the
electron probability into the flipped state via multimode interference.Comment: accepted by PR
Potentially inappropriate medication in older participants of the Berlin Aging Study II (BASE-II) - Sex differences and associations with morbidity and medication use
INTRODUCTION:
Multimorbidity in advanced age and the need for drug treatment may lead to polypharmacy, while pharmacokinetic and pharmacodynamic changes may increase the risk of adverse drug events (ADEs).
OBJECTIVE:
The aim of this study was to determine the proportion of subjects using potentially inappropriate medication (PIM) in a cohort of older and predominantly healthy adults in relation to polypharmacy and morbidity.
METHODS:
Cross-sectional data were available from 1,382 study participants (median age 69 years, IQR 67-71, 51.3% females) of the Berlin Aging Study II (BASE-II). PIM was classified according to the EU(7)-PIM and German PRISCUS (representing a subset of the former) list. Polypharmacy was defined as the concomitant use of at least five drugs. A morbidity index (MI) largely based on the Charlson Index was applied to evaluate the morbidity burden.
RESULTS:
Overall, 24.1% of the participants were affected by polypharmacy. On average, men used 2 (IQR 1-4) and women 3 drugs (IQR 1-5). According to PRISCUS and EU(7)-PIM, 5.9% and 22.6% of participants received at least one PIM, while use was significantly more prevalent in females (25.5%) compared to males (19.6%) considering EU(7)-PIM (p = 0.01). In addition, morbidity in males receiving PIM according to EU(7)-PIM was higher (median MI 1, IQR 1-3) compared to males without PIM use (median MI 1, IQR 0-2, p<0.001).
CONCLUSION:
PIM use occurred more frequently in women than in men, while it was associated with higher morbidity in males. As expected, EU(7)-PIM identifies more subjects as PIM users than the PRISCUS list but further studies are needed to investigate the differential impact of both lists on ADEs and outcome.
KEY POINTS:
We found PIM use to be associated with a higher number of regular medications and with increased morbidity. Additionally, we detected a higher prevalence of PIM use in females compared to males, suggesting that women and people needing intensive drug treatment are patient groups, who are particularly affected by PIM use
An Analysis by Synthesis Approach for Automatic Vertebral Shape Identification in Clinical QCT
Quantitative computed tomography (QCT) is a widely used tool for osteoporosis
diagnosis and monitoring. The assessment of cortical markers like cortical bone
mineral density (BMD) and thickness is a demanding task, mainly because of the
limited spatial resolution of QCT. We propose a direct model based method to
automatically identify the surface through the center of the cortex of human
vertebra. We develop a statistical bone model and analyze its probability
distribution after the imaging process. Using an as-rigid-as-possible
deformation we find the cortical surface that maximizes the likelihood of our
model given the input volume. Using the European Spine Phantom (ESP) and a high
resolution \mu CT scan of a cadaveric vertebra, we show that the proposed
method is able to accurately identify the real center of cortex ex-vivo. To
demonstrate the in-vivo applicability of our method we use manually obtained
surfaces for comparison.Comment: Presented on German Conference on Pattern Recognition (GCPR) 2018 in
Stuttgar
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