11,874 research outputs found
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Composite guidance scaffolds for neural tissue engineering
No abstract available
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Inhibitory effects of soluble fibronectin fractions on cultured neurones
No abstract available
Increased GFAP immunoreactivity by astrocytes in response to contact with dorsal root ganglia cells in a 3D culture model
Failure of repair mechanisms in the injured CNS is widely
attributed to the inhibitory environment of the lesion site,
most notably the formation of the glial scar which forms a
physical and physiological barrier to axon regeneration. We developed an in vitro 3D cell culture model to investigate the
response of astrocytes to cells found at the inhibitory
interfaces formed following damage to the spinal cord.
CellTrackerTM labelled dissociated DRGs were seeded onto
astrocyte-populated collagen gels and maintained in culture
for 5 days. Astrocytes near the DRG interface showed marked
GFAP up-regulation and adopted a reactive morphology
which was observed up to 1mm away. Intensity of GFAP
fluorescence at this interface was 3 fold higher than that seen
away from the interface or in controls (astrocyte only gels).
Furthermore, the presence of DRG conditioned medium was
not capable alone of eliciting this response. In conclusion this
model may provide a useful tool for understanding reactive
astrogliosis in response to cells found at inhibitory interfaces
following spinal cord or dorsal root injury. The contact
between astrocytes and satellite cells may be enough to induce
astrocyte reactivity and formation of the gliotic scar, or this
contact may induce the secretion of a soluble factor which is not
released from DRG cultures under physiological conditions
Lifeguard: Local Health Awareness for More Accurate Failure Detection
SWIM is a peer-to-peer group membership protocol with attractive scaling and
robustness properties. However, slow message processing can cause SWIM to mark
healthy members as failed (so called false positive failure detection), despite
inclusion of a mechanism to avoid this.
We identify the properties of SWIM that lead to the problem, and propose
Lifeguard, a set of extensions to SWIM which consider that the local failure
detector module may be at fault, via the concept of local health. We evaluate
this approach in a precisely controlled environment and validate it in a
real-world scenario, showing that it drastically reduces the rate of false
positives. The false positive rate and detection time for true failures can be
reduced simultaneously, compared to the baseline levels of SWIM
Abnormal attentions towards the British Royal Family. Factors associated with approach and escalation
Abnormal approach and escalation from communication to physical intrusion are central concerns in managing risk to prominent people. This study was a retrospective analysis of police files of those who have shown abnormal attentions toward the British Royal Family. Approach (n = 222), compared with communication only (n = 53), was significantly associated with specific factors, most notably serious mental illness and grandiosity. In a sample of those who engaged in abnormal communication (n = 132), those who approached (n = 79) were significantly more likely to evidence mental illness and grandiosity, to use multiple communications, to employ multiple means of communication, and to be driven by motivations that concerned a personal entitlement to the prominent individual. Logistic regression produced a model comprising grandiosity, multiple communications, and multiple means of communication, for which receiver operating characteristic (ROC) analysis gave an area under the curve (AUC) of 0.82. The implications of these findings are discussed in relation to those for other target groups
Forward Exchange Market Unbiasedness: The Case of the Australian Dollar Since 1984
This paper implements a new statistical approach to robust regression with nonstationary time series. The methods are presently under theoretical development in other work, and are briefly exposited here. They allow us to perform regressions in levels with nonstationary time series data, they accommodate data distributions with heavy tails and they permit serial dependence and temporal heterogeneity of unknown form in the equation errors. With these features the methods are well suited to applications with frequently sampled exchange rate data, which generally display all of these empirical characteristics. Our application is to daily data on spot and forward exchange rates between the Australian and US dollars over the period 1984-1991 following the deregulation of the Australian foreign exchange market. We find big differences between the robust and the non-robust regression outcomes and in the associated statistical tests of the hypothesis that the forward rate is an unbiased predictor of the future spot rate. The robust regression tests reject the unbiasedness hypothesis but still give the forward rate an important role as a predictor of the future spot rate.
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Force transmission across a core-sheath interface in peripheral nerves [poster presentation]
No abstract - poster presentation
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Engineering of nano-microscale lamellae in a model collagen-based scaffold
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