713 research outputs found
Monitoring techniques for the manufacture of tapered optical fibers
The use of a range of optical techniques to monitor the process of fabricating optical fiber tapers is investigated. Thermal imaging was used to optimize the alignment of the optical system; the transmission spectrum of the fiber was monitored to confirm that the tapers had the required optical properties and the strain induced in the fiber during tapering was monitored using in-line optical fiber Bragg gratings. Tapers were fabricated with diameters down to 5 Ī¼m and with waist lengths of 20 mm using single-mode SMF-28 fiber
GrameneMart: the BioMart data portal for the Gramene project
Gramene is a well-established resource for plant comparative genome analysis. Data are generated through automated and curated analyses and made available through web interfaces such as GrameneMart. The Gramene project was an early adopter of the BioMart software, which remains an integral and well-used component of the Gramene website. BioMart accessible data sets include plant gene annotations, plant variation catalogues, genetic markers, physical mapping entities, public DNA/mRNA sequences of various types and curated quantitative trait loci for various species. Database URL: http://www.gramene.org/biomart/martview
Postulated Role of Vasoactive Neuropeptide-Related Immunopathology of the Blood Brain Barrier and Virchow-Robin Spaces in the Aetiology of Neurological-Related Conditions
Vasoactive neuropeptides (VNs) such as pituitary
adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide
(VIP) have critical roles as neurotransmitters, vasodilators including perfusion
and hypoxia regulators, as well as immune and nociception modulators.
They have key roles in blood vessels in the central nervous system (CNS)
including maintaining functional integrity of the blood brain barrier (BBB)
and blood spinal barrier (BSB). VNs are potent activators of adenylate cyclase and thus
also have a key role in cyclic AMP production affecting regulatory T cell and
other immune functions. Virchow-Robin spaces (VRSs) are perivascular compartments
surrounding small vessels within the CNS and contain VNs.
Autoimmunity of VNs or VN receptors may affect BBB and VRS function and,
therefore, may contribute to the aetiology of neurological-related conditions
including multiple sclerosis, Parkinson's disease, and amyotrophic lateral sclerosis.
VN autoimmunity will likely affect CNS and immunological homeostasis.
Various pharmacological and immunological treatments including phosphodiesterase inhibitors
and plasmapheresis may be indicated
Vasoactive neuropeptides in clinical ophthalmology: An association with autoimmune retinopathy?
The mammalian eye is protected against pathogens and inflammation in a relatively immune-privileged environment. Stringent mechanisms are activated that regulate external injury, infection, and autoimmunity. The eye contains a variety of cells expressing vasoactive neuropeptides (VNs), and their receptors, located in the sclera, cornea, iris, ciliary body, ciliary process, and the retina. VNs are important activators of adenylate cyclase, deriving cyclic adenosine monophosphate (cAMP) from adenosine triphosphate (ATP). Impairment of VN function would arguably impede cAMP production and impede utilization of ATP. Thus VN autoimmunity may be an etiological factor in retinopathy involving perturbations of purinergic signaling. A sound blood supply is necessary for the existence and functional properties of the retina. This paper postulates that impairments in the endothelial barriers and the bloodāretinal barrier, as well as certain inflammatory responses, may arise from disruption to VN function. Phosphodiesterase inhibitors and purinergic modulators may have a role in the treatment of postulated VN autoimmune retinopathy
Development and application of optical fibre strain and pressure sensors for in-flight measurements
Fibre optic based sensors are becoming increasingly viable as replacements for traditional
flight test sensors. Here we present laboratory, wind tunnel and flight test results of fibre
Bragg gratings (FBG) used to measure surface strain and an extrinsic fibre
FabryāPerot
interferometric (EFFPI) sensor used to measure unsteady pressure. The calibrated full
scale resolution and bandwidth of the FBG and EFFPI sensors were shown to be 0.29% at
2.5 kHz up to 600 Ī¼Īµ and 0.15% at up to 10 kHz respectively up to 400 Pa. The wind tunnel
tests, completed on a 30% scale model, allowed the EFFPI sensor to be developed before
incorporation with the FBG system into a Bulldog aerobatic light aircraft. The aircraft was
modified and certified based on Certification Standards 23 (CS-23) and flight tested with
steady and dynamic manoeuvres. Aerobatic dynamic manoeuvres were performed in flight
including a spin over a g-range ā1g to +4g and demonstrated both the FBG and the EFFPI
instruments to have sufficient resolution to analyse the wing strain and fuselage unsteady
pressure characteristics. The steady manoeuvres from the EFFPI sensor matched the wind
tunnel data to within experimental error while comparisons of the flight test and wind tunnel
EFFPI results with a Kulite pressure sensor showed significant discrepancies between the two
sets of data, greater than experimental error. This issue is discussed further in the paper
Functional neuroimaging of conversion disorder: The role of ancillary activation
AbstractBackgroundPrevious functional neuroimaging studies investigating the neuroanatomy of conversion disorder have yielded inconsistent results that may be attributed to small sample sizes and disparate methodologies. The objective of this study was to better define the functional neuroanatomical correlates of conversion disorder.MethodsTen subjects meeting clinical criteria for unilateral sensory conversion disorder underwent fMRI during which a vibrotactile stimulus was applied to anesthetic and sensate areas. A block design was used with 4Ā s of stimulation followed by 26Ā s of rest, the pattern repeated 10 times. Event-related group averages of the BOLD response were compared between conditions.ResultsAll subjects were right-handed females, with a mean age of 41. Group analyses revealed 10 areas that had significantly greater activation (pĀ <Ā .05) when stimulation was applied to the anesthetic body part compared to the contralateral sensate mirror region. They included right paralimbic cortices (anterior cingulate cortex and insula), right temporoparietal junction (angular gyrus and inferior parietal lobule), bilateral dorsolateral prefrontal cortex (middle frontal gyri), right orbital frontal cortex (superior frontal gyrus), right caudate, right ventral-anterior thalamus and left angular gyrus. There was a trend for activation of the somatosensory cortex contralateral to the anesthetic region to be decreased relative to the sensate side.ConclusionsSensory conversion symptoms are associated with a pattern of abnormal cerebral activation comprising neural networks implicated in emotional processing and sensory integration. Further study of the roles and potential interplay of these networks may provide a basis for an underlying psychobiological mechanism of conversion disorder
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