Permanent URI for this collection
Browse
Recent Submissions
Publication Ultra-sensitive label free imaging below the resolution limit(SPIE (Society of Photo-optical Instrumentation Engineers) Digital Library, 2019-02-02) Alexandrov, Sergey; McGrath, James; Sheppard, Colin J. R.; Boccafoschi, Francesca; Giannini, Cinzia; Sibillano, Teresa; Subhash, Hrebesh; Hogan, Josh; Leahy, James J.; Horizon 2020Almost all known nanoscopy methods rely upon the contrast created by fluorescent labels attached to the object of interest. This causes limitations on their applicability to in vivo imaging. A new label-free spectral encoding of spatial frequency (SESF) approach to nanoscale probing of three-dimensional structures has been developed. It was demonstrated that spatial frequencies, encoded with optical wavelengths, can be passed though the optical system independently of the resolution of the imaging system. As a result information about small size structures can be detected even using a low resolution imaging system. Different versions of the SESF imaging have been published [1-7], including a novel contrast mechanism for high resolution imaging [1], real time nano-sensitive imaging [2], reconstruction the axial (along depth) spatial frequency profiles for each point with nano-sensitivity to structural changes [3], and the adaptation of the SESF approach to depth resolved imaging [4,5]. Recently the SESF approach has been applied to overcome the diffraction limit and dramatically improve resolution [6,7]. Here we present further development of the SESF approach including correlation mapping SESF imaging. Both results of numerical simulation and preliminary experimental results, including biological samples, will be presented. [1] Alexandrov, et.al., Opt. Lett. 36 3323 (2011). [2] Alexandrov, et.al., Opt. Express 20 (8) 9203 (2012). [3] Alexandrov, et.al., Appl. Phys. Let., 101 033702 (2012). [4] Uttam, et.al., Opt. Express, 21, 7488 (2013). [5] Alexandrov, et.al., Nanoscale, 6, 3545 (2014). [6] Alexandrov, et.al., Sci. Rep., 5, doi: 10.1038/srep13274 (2015). [7] Alexandrov, et.al., J. Biophotonics, https://doi.org/10.1002/jbio.201700385 (2018).Publication Label free ultra-sensitive imaging with sub-diffraction spatial resolution(IEEE, 2019-07-09) Alexandrov, Sergey; Das, Nandan; McGrath, James; Owens, Peter; Sheppard, Colin J. R.; Boccafoschi, Francesca; Giannini, Cinzia; Sibillano, Teresa; Subhash, Hrebesh; Leahy, Martin; Horizon 2020; Galway University Foundation; Irish Research CouncilIn this paper, we show a new way to break the resolution limit and dramatically improve sensitivity to structural changes. To realize it we developed a novel label free contrast mechanism, based on the spectral encoding of spatial frequency (SESF) approach. The super-resolution SESF (srSESF) microscopy is based on reconstruction of the axial spatial frequency (period) profiles for each image point and comparison of these profiles to form super-resolution image. As a result, the information content of images is dramatically improved in comparison with conventional microscopy. Numerical simulation and experiments demonstrate significant improvement in sensitivity and resolution.Publication Experimental assessment of MRI-induced temperature change and SAR distributions in phantoms(NUI Galway, 2017-11-14) Blackwell, J.; Van der Putten, Wil; Tuohy, Brendan; Colgan, NiallDuring an MR procedure, most of the transmitted RF power is transformed into heat within the patients’ tissue resulting from resistive losses, referred to as the specific energy absorption rate(SAR) (2). The EU standardisation has mandated that all scanners must measure SAR in patients and develop system safeguards to ensure that the limits(IEC60602-3-33) are not exceeded. Accurate estimation of SAR is critical in safeguarding patients who may be unconscious/sedated, have implants or are pregnant. Modern MRI systems can easily exceed safe SAR levels (1) requiring the independent verification of manufacturers SAR estimations.Publication Entertaining physics education: using an astronomy board game to enhance student learning and motivation(GIREP-MPTL 2018, 2018-07-09) Cardinot, Adriana; Fairfield, Jessamyn A.; CAPES-Brazil; Institute of Physics, IrelandThis study examines the effects of a novel Astronomy Board Game on students science performance, their attitudes towards learning Science through games and their perception of scientists. Post-primary students in Ireland and the UK of various ages (n=119) took part in the pilot trial. Data were collected via pre- and post-test, feedback questionnaire and focus groups. The results indicated significant improvements in student s learning of astronomy topics, suggesting the inclusion of games in the classroom affects student learning and perception of scientists.Publication Asteroid Day: a vehicle for raising public awareness of astronomy and space exploration among primary students in Ireland(NUI Galway, 2018-03-24) Cardinot, Adriana; Shearer, Andy; Fairfield, Jessamyn A.; CAPES-Brazil; Centre for Astronomy, School of Physics, NUI Galway; Marketing and Communications Office, NUI GalwayAsteroid Day is a global awareness campaign which takes place annually to learn about asteroids, their impact and to increase awareness on how we can protect the Earth from future asteroid impacts. At the event students tested their own hypothesis and carried out investigations to discover new concepts in Astronomy. The activities encouraged learning and promoted positive attitudes towards Astronomy.Publication Indoor air quality and thermal comfort in Irish retrofitted energy efficient homes(School of Physics, NUI Galway, 2017-03-14) Coggins, Marie; Broderick, Aine; Byrne, Miriam; Environmental Protection AgencyResults from an Irish study comparing the concentrations of 10 indoor air pollutants and occupant comfort in 15 naturally ventilated three bed semi-detached two storey homes before and after the implementation of energy efficient retrofit will be presented. As part of the energy retrofit homes received new windows and doors, an upgraded heating system, attic insulation, and wall vents along with pumped beaded wall insulation into the wall cavity. The energy upgrades resulted in building air tightness levels increasing from 9.26 m3/h.m2 to values of between 5.53 m3/h.m2 and 8.61 m3/h.m2. Temperature and relative humidity (RH), along with concentrations of benzene, toluene, ethylbenzene, xylene, TVOCs, PM2.5, CO2, and CO were measured over a 24-hour period in the main living area and main bedroom of each home. Concentrations of NO2 and formaldehyde were measured in the living room only. Contextual information regarding the household and occupant activities such as when the heating system was used during the monitoring period was collected using occupant diaries and questionnaires.Publication Experimental and numerical assessment of MRI-induced temperature change and SAR distributions in phantoms(Springer Verlag, 2017-06) Colgan, Niall; Van der Putten, Wil; Tuohy, Brendan; Eskola, H., Väisänen, O., Viik, J., Hyttinen, J.; |~|During an MR procedure, most of the transmitted RF power is transformed into heat within the patient’s tissue and implants as a result of resistive losses which is referred to as the specific energy absorption rate (SAR) (1). The European committee for electrotechnical standardisation (CENELEC) has mandated that all scanners must measure the specific absorption rate of radiofrequency in patients and develop system safeguards to ensure that the limits set out IEC 60602-3-33 are not exceeded. Accurate estimation of SAR is critical to safeguard in unconscious/sedated patients, patients with compromised thermoregulation, implant patients, pregnant patients and neonates who require an MRI procedure. The increased static field strength and RF duty cycle capabilities in modern MRI scanners means that systems can easily exceed safe SAR levels for patients (2). Advisory protocols routine used to establish QA protocols do not have advise on the testing of SAR levels in MRI and this is not routinely measured in annual medical physics QA. There is increasing need to verify the manufacturers SAR estimations.