365 research outputs found
Orbital size measurement based on computed tomography imaging for surgical safety
Determining the orbital size makes it possible to manoeuvre safely within theorbit during a surgical procedure. Based on the measurements performed ona multi-layer head computed tomography images, the length was determined of the medial, superior, inferior and lateral orbital walls. Also angles were determined between the superior and inferior walls, between the medial and lateral walls, between the inferior wall and Frankfurt plane and between the anterior and posterior segments of the orbital wall. With these measurements it was possible to establish that the safe space for surgical exploration of the orbit (that is the space between the orbital margin and optic canal) is approximately 40 mm. Moreover, it was determined that the medial wall is parallel to the vertical axis of the body and that the angle between the inferior wall and the Frankfurt plane is 19.7°. The angle between the posterior segment of the inferior wall (posterior to the inferior orbital fissure) and the anterior segment is 130.8°. These data will significantly increase the safety of orbital surgeries
Influence of husbandry procedures on mouse locomotor activity
The currently used raL models of obesity and diabetes are derived from either Zucker or from Koletsky rats. Recently, we identified a spontaneous obese rat from out Wistar colony which is maintained as an inbred stock for the past 75 years. Initially, one of the male progeny in a litter was observed to have abnormal body weight for its age. The parents of this ral were identified, the progeny selectively bred, and a colony has been developed. This is designated as WNIN-0b. The colony is maintained by mating heterozygous animals (+/ob), as the homozygous (ob/ob) were found to be infertile. The trait is carried as an autosomal recessive mutation and the colony is currenfly in F7 generation.Obesity is visible in these mutants around 35 days of age. They are hyperphagic and reach a body weight of 500â600 g by 105 days of age. âKinkyâ tail is characteristic of this mutant and this is visible around 50-60 days. Sexual maturity is delayed in female obese mutants, as judged by the day of vaginal opening. The animals are cuglyccmic and show hyperinsulinaemia, hypertriglyceridaemia, arid hypercholesterolemia. Another mutant showing hyperglycemia is also obtained fromthe obese colony. Unlike earlier models which are essentially derived from a randomAbred stock, this is the first report of a rat obese model, developed spontaneously from an inbred strain
An algorithm for preoperative differential diagnostics of parotid tumours on the basis of their dynamic and diffusion-weighted magnetic resonance images: a retrospective analysis of 158 cases
Background: To verify the usefulness of a new algorithm for preoperative differential diagnostics of parotid tumours on the basis of their dynamic and diffusion- -weighted magnetic resonance imaging (MRI).
Materials and methods: The retrospective analysis included 158 consecutive surgical patients with parotid tumours. Aside from ultrasound-guided fine needle biopsy, the protocol of preoperative evaluation included dynamic and diffusion-weighted MRI. According to the new diagnostic algorithm, the result of fine needle biopsy was considered only in the case of lesions with time to peak enhancement (Tpeak) > 60 s and washout rate (WR) †30% on dynamic MRI and apparent diffusion coefficient (ADC) †1.7 à 103 mm/s2 on diffusion-weighted MRI, or those presenting with concomitant lymphadenopathy. The accuracy of this algorithm was verified against final histopathological diagnoses.
Results: The new algorithm gave 10 true positive and 2 false positive results, as well as 132 and 14 true and false negative results, respectively. Its sensitivity and specificity (41.7% and 98.5%, respectively) were the same as in the case of fine needle biopsy alone. None of the 59 tumours that were qualified as benign solely on the basis of preoperative MRI turned out to be malignant on postoperative histopathological examination.
Conclusions: Interpreted together, dynamic and diffusion-weighted MRIs provide the same accuracy in preoperative differential diagnostics of parotid tumours as fine needle biopsy. This substantiates the use of diagnostic algorithms in which biopsy would serve mostly as a secondary test to verify selected ambiguous radiological diagnoses. (Folia Morphol 2018; 77, 1: 29â35)
Scintillator counters with WLS fiber/MPPC readout for the side muon range detector (SMRD)of the T2K experiment
The T2K neutrino experiment at J-PARC uses a set of near detectors to measure
the properties of an unoscillated neutrino beam and neutrino interaction
cross-sections. One of the sub-detectors of the near-detector complex, the side
muon range detector (SMRD), is described in the paper. The detector is designed
to help measure the neutrino energy spectrum, to identify background and to
calibrate the other detectors. The active elements of the SMRD consist of 0.7
cm thick extruded scintillator slabs inserted into air gaps of the UA1 magnet
yokes. The readout of each scintillator slab is provided through a single WLS
fiber embedded into a serpentine shaped groove. Two Hamamatsu multi-pixel
avalanche photodiodes (MPPC's) are coupled to both ends of the WLS fiber. This
design allows us to achieve a high MIP detection efficiency of greater than
99%. A light yield of 25-50 p.e./MIP, a time resolution of about 1 ns and a
spatial resolution along the slab better than 10 cm were obtained for the SMRD
counters.Comment: 7 pages, 4 figures; talk at TIPP09, March 12-17, Tsukuba, Japan; to
be published in the conference proceeding
Performance of a small size telescope (SST-1M) camera for gamma-ray astronomy with the Cherenkov Telescope Array
The foreseen implementations of the Small Size Telescopes (SST) in CTA will
provide unique insights into the highest energy gamma rays offering fundamental
means to discover and under- stand the sources populating the Galaxy and our
local neighborhood. Aiming at such a goal, the SST-1M is one of the three
different implementations that are being prototyped and tested for CTA. SST-1M
is a Davies-Cotton single mirror telescope equipped with a unique camera
technology based on SiPMs with demonstrated advantages over classical
photomultipliers in terms of duty-cycle. In this contribution, we describe the
telescope components, the camera, and the trigger and readout system. The
results of the commissioning of the camera using a dedicated test setup are
then presented. The performances of the camera first prototype in terms of
expected trigger rates and trigger efficiencies for different night-sky
background conditions are presented, and the camera response is compared to
end-to-end simulations.Comment: All CTA contributions at arXiv:1709.0348
Development of a strategy for calibrating the novel SiPM camera of the SST-1M telescope proposed for the Cherenkov Telescope Array
CTA will comprise a sub-array of up to 70 small size telescopes (SSTs) at the
southern array. The SST-1M project, a 4 m-diameter Davies Cotton telescope with
9 degrees FoV and a 1296 pixels SiPM camera, is designed to meet the
requirements of the next generation ground based gamma-ray observatory CTA in
the energy range above 3 TeV. Silicon photomultipliers (SiPM) cameras of
gamma-ray telescopes can achieve good performance even during high night sky
background conditions. Defining a fully automated calibration strategy of SiPM
cameras is of great importance for large scale production validation and online
calibration. The SST-1M sub-consortium developed a software compatible with CTA
pipeline software (CTApipe). The calibration of the SST-1M camera is based on
the Camera Test Setup (CTS), a set of LED boards mounted in front of the
camera. The CTS LEDs are operated in pulsed or continuous mode to emulate
signal and night sky background respectively. Continuous and pulsed light data
analysis allows us to extract single pixel calibration parameters to be used
during CTA operation.Comment: All CTA contributions at arXiv:1709.0348
Control Software for the SST-1M Small-Size Telescope prototype for the Cherenkov Telescope Array
The SST-1M is a 4-m Davies--Cotton atmospheric Cherenkov telescope optimized
to provide gamma-ray sensitivity above a few TeV. The SST-1M is proposed as
part of the Small-Size Telescope array for the Cherenkov Telescope Array (CTA),
the first prototype has already been deployed. The SST-1M control software of
all subsystems (active mirror control, drive system, safety system,
photo-detection plane, DigiCam, CCD cameras) and the whole telescope itself
(master controller) uses the standard software design proposed for all CTA
telescopes based on the ALMA Common Software (ACS) developed to control the
Atacama Large Millimeter Array (ALMA). Each subsystem is represented by a
separate ACS component, which handles the communication to and the operation of
the subsystem. Interfacing with the actual hardware is performed via the OPC UA
communication protocol, supported either natively by dedicated industrial
standard servers (PLCs) or separate service applications developed to wrap
lower level protocols (e.g. CAN bus, camera slow control) into OPC UA. Early
operations of the telescope without the camera were already carried out. The
camera is fully assembled and is capable to perform data acquisition using
artificial light source.Comment: In Proceedings of the 35th International Cosmic Ray Conference
(ICRC2017), Busan, Korea. All CTA contributions at arXiv:1709.0348
Software design for the control system for Small-Size Telescopes with single-mirror of the Cherenkov Telescope Array
The Small-Size Telescope with single-mirror (SST-1M) is a 4 m Davies-Cotton
telescope and is among the proposed telescope designs for the Cherenkov
Telescope Array (CTA). It is conceived to provide the high-energy ( few TeV)
coverage. The SST-1M contains proven technology for the telescope structure and
innovative electronics and photosensors for the camera. Its design is meant to
be simple, low-budget and easy-to-build industrially.
Each device subsystem of an SST-1M telescope is made visible to CTA through a
dedicated industrial standard server. The software is being developed in
collaboration with the CTA Medium-Size Telescopes to ensure compatibility and
uniformity of the array control. Early operations of the SST-1M prototype will
be performed with a subset of the CTA central array control system based on the
Alma Common Software (ACS). The triggered event data are time stamped,
formatted and finally transmitted to the CTA data acquisition.
The software system developed to control the devices of an SST-1M telescope
is described, as well as the interface between the telescope abstraction to the
CTA central control and the data acquisition system.Comment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
Prototype of the SST-1M Telescope Structure for the Cherenkov Telescope Array
A single-mirror small-size (SST-1M) Davies-Cotton telescope with a dish
diameter of 4 m has been built by a consortium of Polish and Swiss institutions
as a prototype for one of the proposed small-size telescopes for the southern
observatory of the Cherenkov Telescope Array (CTA). The design represents a
very simple, reliable, and cheap solution. The mechanical structure prototype
with its drive system is now being tested at the Institute of Nuclear Physics
PAS in Krakow. Here we present the design of the prototype and results of the
performance tests of the structure and the drive and control system.Comment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
DigiCam - Fully Digital Compact Read-out and Trigger Electronics for the SST-1M Telescope proposed for the Cherenkov Telescope Array
The SST-1M is one of three prototype small-sized telescope designs proposed
for the Cherenkov Telescope Array, and is built by a consortium of Polish and
Swiss institutions. The SST-1M will operate with DigiCam - an innovative,
compact camera with fully digital read-out and trigger electronics. A high
level of integration will be achieved by massively deploying state-of-the-art
multi-gigabit transmission channels, beginning from the ADC flash converters,
through the internal data and trigger signals transmission over backplanes and
cables, to the camera's server link. Such an approach makes it possible to
design the camera to fit the size and weight requirements of the SST-1M
exactly, and provide low power consumption, high reliability and long lifetime.
The structure of the digital electronics will be presented, along with main
physical building blocks and the internal architecture of FPGA functional
subsystems.Comment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
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