104 research outputs found
Robot assisted stapedotomy ex vivo with an active handheld instrument
Micron is a fully handheld active
micromanipulator that helps to improve position accuracy and
precision in microsurgery by cancelling hand tremor. This
work describes adaptation, tuning, and testing of the Micron
system for stapedotomy, a microsurgical procedure performed
in the middle ear to restore hearing that requires accurate
manipulation in narrow spaces. Two end-effectors, a handle,
and a brace (or rest) were designed and prototyped. The
control system was adapted for the new hardware. The system
was tested ex vivo in stapedotomy procedure comparing
manually-performed and Micron-assisted surgical tasks.
Tremor amplitude was found to be reduced significantly.
Further testing is needed in order to obtain statistically
significant results regarding other parameters dealing with
regularity of the fenestra shap
Genomics in neurodevelopmental disorders: an avenue to personalized medicine
Despite the remarkable number of scientific breakthroughs of the last 100 years, the treatment of neurodevelopmental
disorders (e.g., autism spectrum disorder, intellectual disability) remains a great challenge. Recent advancements in
genomics, such as whole-exome or whole-genome sequencing, have enabled scientists to identify numerous
mutations underlying neurodevelopmental disorders. Given the few hundred risk genes that have been discovered,
the etiological variability and the heterogeneous clinical presentation, the need for genotype — along with phenotype-
based diagnosis of individual patients has become a requisite. In this review we look at recent advancements in
genomic analysis and their translation into clinical practice
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
MAGIC and Fermi-LAT gamma-ray results on unassociated HAWC sources
The HAWC Collaboration released the 2HWC catalogue of TeV sources, in which 19 show no association with any known high-energy (HE; E greater than or similar to 10 GeV) or very-high-energy (VHE; E greater than or similar to 300 GeV) sources. This catalogue motivated follow-up studies by both the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) and Fermi-LAT (Large Area Telescope) observatories with the aim of investigating gamma-ray emission over a broad energy band. In this paper, we report the results from the first joint work between High Altitude Water Cherenkov (HAWC), MAGIC, and Fermi-LAT on three unassociated HAWC sources: 2HWC J2006+341, 2HWC J1907+084*, and 2HWC J1852+013*. Although no significant detection was found in the HE and VHE regimes, this investigation shows that a minimum 1 degrees extension (at 95 per cent confidence level) and harder spectrum in the GeV than the one extrapolated from HAWC results are required in the case of 2HWC J1852+013*, whilst a simply minimum extension of 0.16 degrees (at 95 per cent confidence level) can already explain the scenario proposed by HAWC for the remaining sources. Moreover, the hypothesis that these sources are pulsar wind nebulae is also investigated in detail
Fuzzy Calibration of Magnetometer in Presence of Surgical Microscope
Abstract—A method is presented for data-driven calibration of the magnetometer in an active handheld microsurgical instrument in the presence of a surgical microscope. The instrument is designed to provide tremor compensation during vitreoretinal microsurgery. An adaptive-network-based fuzzy inference system is used to generate a calibration based on data points collected at random locations throughout the workspace. Inputs to the model include the tilt angle and the twist angle about the long axis of the instrument, obtained from accelerometer readings, and the azimuth of the apparent magnetic north, obtained from the magnetometer readings. The model outputs the true azimuth angle of the instrument. Results from preliminary testing of the method are presented.
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