Keratoconus associated with CSNB1.
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Adult↗
Biomedical subjects
R P Hagan
Publications and source records attributed to R P Hagan.
Removal of eye movement artefacts from single channel recordings of retinal evoked potentials using synchronous dynamical embedding and independent component analysis.
A system is described for the removal of eye movement and blink artefacts from single channel pattern reversal electroretinogram recordings of very poor signal-to-noise ratios. Artefacts are detected and removed by using a blind source separation technique based on the jadeR independent component analysis algorithm. The single channel data are arranged as a series of overlapping time-delayed vectors forming a dynamical embedding matrix. The structure of this matrix is constrained to the phase of the stimulation epoch: the term synchronous dynamical embedding is coined. A novel method using a marker channel with a non-independent synchronous feature is employed to identify the single most relevant source estimation for reconstruction and signal recovery. This method is non-lossy, all underlying signal being recovered. In synthetic datasets of defined noise content and in standardised real data recordings, the performance of this technique is compared to conventional fixed-threshold hard-limit rejection. The most significant relative improvements are achieved when movement and blink artefacts are greatest: no improvement is demonstrable for the random noise only situation.
Artifacts↗
Cellular interactions during the development of autoimmunity in a fetal lamb model of self-antigen deprivation.
Anti-thyroid autoimmune responses have been examined in fetal lambs, the immune systems of which had matured in the absence of exposure to thyroid-specific antigens. The lymphocytic infiltrate in self-thyroid tissue reintroduced into autoimmune lambs showed well-differentiated B and T cell domains. However, T cells from these fetuses were not sensitized against ovine thyroglobulin nor did serum antibodies appear against ovine thyroglobulin or thyroid peroxidase. In the light of these observations, it is inferred that the primary abnormality in the immune systems of fetuses deprived of exposure to thyroid autoantigens is likely to be a failure of the development of a normal T cell subpopulation responsible for down-regulation of autoreactivity. It is also concluded that overt autoimmunity develops only when these fetuses are challenged with thyroid tissue and that B cells may undertake an antigen-presentation role in its induction.
Animals↗
The kinematics and kinetics of slipknots for arthroscopic Bankart repair.
An apparatus has been developed to enable the in vitro measurement of the kinematics and kinetics of a slipknot, both while the knot is being tightened and with the knot in place and the tension removed. During tightening, the apparatus provides a linearly increasing resistance, which may be considered analogous to the resistance experienced when the labrum is drawn toward and apposed to the edge of the glenoid cavity during a Bankart repair. The tension to close the knot is measured with a tensiometer, in tandem with the closure of the capsule model onto the bone anchor, which is measured with a datalogger. The tightening tension was limited to 25 N and intraoperator and interoperator comparisons were made for four knots tied by six participants. Failure of a knot was taken to be reverse slippage of 2 mm. A second criterion of ease of slide was used to assess each knot. We found wide interoperator variability with regard to slipknot tying. A methodology for quality control of slipknot tying is presented.
Arthroscopy↗