1,344 research outputs found
Differences in EMG burst patterns during grasping dexterity tests and activities of daily living
The aim of this study was to characterize the muscle activation patterns which underlie the performance of two commonly used grasping patterns and compare the characteristics of such patterns during dexterity tests and activities of daily living. EMG of flexor digitorum and extensor digitorum were monitored from 6 healthy participants as they performed three tasks related to activities of daily living (picking up a coin, drinking from a cup, feeding with a spoon) and three dexterity tests (Variable Dexterity Test-Precision, Variable Dexterity Test-Cylinder, Purdue Pegboard Test). A ten-camera motion capture system was used to simultaneously acquire kinematics of index and middle fingers. Spatiotemporal aspects of the EMG signals were analyzed and compared to metacarpophalangeal joint angle of index and middle fingers. The work has shown that a common rehabilitation test such as the Purdue Pegboard test is a poor representation of the muscle activation patterns for activities of daily living. EMG and joint angle patterns from the Variable Dexterity Tests which has been designed to more accurately reflect a range of ADl's were consistently comparable with tasks requiring precision and cylinder grip, reaffirming the importance of object size and shape when attempting to accurately assess hand function
Some Recent Developments in SHM Based on Nonstationary Time Series Analysis
Many of the algorithms used for structural health monitoring (SHM) are based on, or motivated by, time series analysis. Quite often, detection methods are variants of approaches developed within the statistical process control (SPC) community. Many of the algorithms used represent mature theory and have a rigorous probabilistic or mathematical basis. However, one of the main issues facing SHM practitioners is that the structures of interest rarely respect the assumptions inherent in deriving algorithms. In the case of time series data, SPC-based approaches usually require the data to be stationary and, unfortunately, SHM data are often nonstationary because of benign variations in the environment of the structure of interest, or because of deliberate operational changes in the use of the structure. This nonstationarity can manifest itself as slowly varying trends on the data or in abrupt switches between regimes. Recent work in nonstationary time series methods for SHM has made considerable progress in accommodating nonstationarity and some of that work is discussed within this paper: in terms of understanding slowly varying trends, the cointegration algorithm from econometrics is presented; for understanding abrupt switches, Bayesian mixtures of experts are presented. Another issue in time series analysis is indirectly related to the assumption of linear behavior of structures and the impact of this assumption is briefly considered in terms of its effects on detection thresholds in SPC-like methods; again, progress has been made recently. Some issues still remain, and these are discussed also
Suppression of planar cell polarity signaling and migration in glioblastoma by Nrdp1-mediated Dvl polyubiquitination.
The lethality of the aggressive brain tumor glioblastoma multiforme (GBM) results in part from its strong propensity to invade surrounding normal brain tissue. Although oncogenic drivers such as epidermal growth factor receptor activation and Phosphatase and Tensin homolog inactivation are thought to promote the motility and invasiveness of GBM cells via phosphatidylinostitol 3-kinase activation, other unexplored mechanisms may also contribute to malignancy. Here we demonstrate that several components of the planar cell polarity (PCP) arm of non-canonical Wnt signaling including VANGL1, VANGL2 and FZD7 are transcriptionally upregulated in glioma and correlate with poorer patient outcome. Knockdown of the core PCP pathway component VANGL1 suppresses the motility of GBM cell lines, pointing to an important mechanistic role for this pathway in glioblastoma malignancy. We further observe that restoration of Nrdp1, a RING finger type E3 ubiquitin ligase whose suppression in GBM also correlates with poor prognosis, reduces GBM cell migration and invasiveness by suppressing PCP signaling. Our observations indicate that Nrdp1 physically interacts with the Vangl1 and Vangl2 proteins to mediate the K63-linked polyubiquitination of the Dishevelled, Egl-10 and Pleckstrin (DEP) domain of the Wnt pathway protein Dishevelled (Dvl). Ubiquitination hinders Dvl binding to phosphatidic acid, an interaction necessary for efficient Dvl recruitment to the plasma membrane upon Wnt stimulation of Fzd receptor and for the propagation of downstream signals. We conclude that the PCP pathway contributes significantly to the motility and hence the invasiveness of GBM cells, and that Nrdp1 acts as a negative regulator of PCP signaling by inhibiting Dvl through a novel polyubiquitination mechanism. We propose that the upregulation of core PCP components, together with the loss of the key negative regulator Nrdp1, act coordinately to promote GBM invasiveness and malignancy
High Voltage in Noble Liquids for High Energy Physics
A workshop was held at Fermilab November 8-9, 2013 to discuss the challenges
of using high voltage in noble liquids. The participants spanned the fields of
neutrino, dark matter, and electric dipole moment physics. All presentations at
the workshop were made in plenary sessions. This document summarizes the
experiences and lessons learned from experiments in these fields at developing
high voltage systems in noble liquids.Comment: 64 pages, 41 figures, 2 table
Hydrogen penetration into titanium from environment in different states
In this paper, the accumulation of hydrogen in titanium from media of different aggregate states is considered, since the accumulation of hydrogen in structural and functional materials, which ultimately can lead to the destruction of structures, essentially depends on the environments in which these structures operate. Obtained: electrolytic and plasma saturation is characterized by hydrogen entrapment by low-temperature traps with weak binding energy (point defects and their complexes, vacancies and their complexes, etc. The method of Siwerst is characterized by capture of high-temperature traps (microcracks of microcracks, intergranular boundaries, etc.)
Neoplastic transformation of porcine mammary epithelial cells in vitro and tumor formation in vivo
BACKGROUND: The mammary glands of pigs share many functional and morphological similarities with the breasts of humans, raising the potential of their utility for research into the mechanisms underlying normal mammary function and breast carcinogenesis. Here we sought to establish a model for the efficient manipulation and transformation of porcine mammary epithelial cells (pMEC) in vitro and tumor growth in vivo. METHODS: We utilized a vector encoding the red florescent protein tdTomato to transduce populations of pMEC from Yorkshire –Hampshire crossbred female pigs in vitro and in vivo. Populations of primary pMEC were then separated by FACS using markers to distinguish epithelial cells (CD140a-) from stromal cells (CD140a+), with or without further enrichment for basal and luminal progenitor cells (CD49f+). These separated pMEC populations were transduced by lentivirus encoding murine polyomavirus T antigens (Tag) and tdTomato and engrafted to orthotopic or ectopic sites in immunodeficient NOD.Cg-Prkdc(scid) Il2rg(tm1Wjl)/SzJ (NSG) mice. RESULTS: We demonstrated that lentivirus effectively transduces pMEC in vitro and in vivo. We further established that lentivirus can be used for oncogenic-transformation of pMEC ex vivo for generating mammary tumors in vivo. Oncogenic transformation was confirmed in vitro by anchorage-independent growth, increased cell proliferation, and expression of CDKN2A, cyclin A2 and p53 alongside decreased phosphorylation of Rb. Moreover, Tag-transformed CD140a- and CD140a-CD49f + pMECs developed site-specific tumors of differing histopathologies in vivo. CONCLUSIONS: Herein we establish a model for the transduction and oncogenic transformation of pMEC. This is the first report describing a porcine model of mammary epithelial cell tumorigenesis that can be applied to the study of human breast cancers. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12885-015-1572-7) contains supplementary material, which is available to authorized users
Mobility of thorium ions in liquid xenon
We present a measurement of the Th ion mobility in LXe at 163.0 K and
0.9 bar. The result obtained, 0.2400.011 (stat) 0.011 (syst)
cm/(kV-s), is compared with a popular model of ion transport.Comment: 6.5 pages,
Observation of single collisionally cooled trapped ions in a buffer gas
Individual Ba ions are trapped in a gas-filled linear ion trap and observed
with a high signal-to-noise ratio by resonance fluorescence. Single-ion storage
times of ~5 min (~1 min) are achieved using He (Ar) as a buffer gas at
pressures in the range 8e-5 - 4e-3 torr. Trap dynamics in buffer gases are
experimentally studied in the simple case of single ions. In particular, the
cooling effects of light gases such as He and Ar and the destabilizing
properties of heavier gases such as Xe are studied. A simple model is offered
to explain the observed phenomenology.Comment: 5 pages, 4 figures, accepted for publication in Phys. Rev. A. Minor
text and figure change
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