SKELETAL AGE ASSESSMENT IN PATIENTS WITH TRANSVERSE MAXILLARY DEFICIT UNDERGOING RAPID MAXILLARY EXPANSION

Aim: The study was governed by two main goals: 1) To assess the skeletal maturation of young patients who were undergoing orthodontic treatment with rapid maxillary expansion; 2) To compare their chronological age with their skeletal maturation stage. Material and methods: Lateral cephalometric radiographs of 74 patients were randomly selected and analyzed. The sample included 51 girls and 23 boys in late mixed and permanent dentition, with an average age of 13.2 (± 2.24) in the range from 9 to 17 years. The assessment of skeletal maturation followed the cervical vertebral maturation (CVM) methods of Baccetti et al. and Lamparski. Results: The results showed 53% consistency and 47% discrepancy between the chronological and skeletal age of the patients. In the age group 9-13.5 years, the discrepancies reached 73.5%. The difference in percentages was statistically significant, p <.001. The discrepancies tended towards higher skeletal age: 80% in the whole sample and 86.25% among patients aged 9 - 13.50 years. The difference between the patients classified in higher and lower stages of skeletal age was statistically significant, p <.001. Conclusion: Chronological age is an unreliable indicator of growth potential in adolescent patients before and after growth spurt. The discrepancy is particularly prominent in patients before growth spurt, where skeletal age suggests a higher level of maturation than predicted by the patients’ chronological age

COMPARISON OF SKELETAL MATURITY AND CHRONOLOGICAL AGE IN BULGARIAN FEMALE AND MALE PATIENTS WITH TRANSVERSE MAXILLARY DEFICIT

Aim: The aim of this study was to compare the skeletal and chronological age of adolescent Bulgarian female and male patients with а transverse maxillary deficit in order to establish the level of consistencies and discrepancies within and between the two sexes. Material and methods: The data included lateral cephalometric radiographs of 74 patients, among whom 51 girls and 23 boys. The patients’ ages ranged between 9 and 17 years, with an average age of 13.2 years (±2.24). The assessment of skeletal maturation followed the cervical vertebral maturation (CVM) methods of Baccetti et al. and Lamparski. Comparison of skeletal and chronological age was performed for patients before age spurt and after age spurt within the female and male groups. The two sexes were compared in view of consistencies and discrepancies between chronological and skeletal age. Results: The results showed a statistically lower percentage of consistencies and a higher percentage of discrepancies in patients before age spurt for both sexes. Vice versa, in patients after age spurt consistencies, constituted a statistically higher percentage for both sexes. As a whole, the female patients had a slightly higher percentage of consistency (54%) between chronological and skeletal age than the male patients (48%), but the difference of 6% was not statistically significant p = 0.73. The discrepancies towards a higher skeletal age constituted 83% of the total number of discrepancies among the female patients and 75% of the discrepancies among the male patients. The difference of 8% was not significant, p = 0.56. The mean chronological age of the female and male patients in each CVS stage was very similar. Conclusion: In patients with incomplete skeletal growth, skeletal age corresponds to a higher level of maturation than predicted by the patients’ chronological age in both female and male patients. The two sexes show similar trends of accelerated skeletal maturation without statistically significant differences. Our results differ from previous findings of the existence of sexual dimorphism in skeletal age maturation

Design of the Life Signature Detection Polarimeter LSDpol

Many biologically produced chiral molecules such as amino acids and sugars show a preference for left or right handedness (homochirality). Light reflected by biological materials such as algae and leaves therefore exhibits a small amount of circular polarization that strongly depends on wavelength. Our Life Signature Detection polarimeter (LSDpol) is optimized to measure these signatures of life. LSDpol is a compact spectropolarimeter concept with no moving parts that instantaneously measures linear and circular polarization averaged over the field of view with a sensitivity of better than 1e-4. We expect to launch the instrument into orbit after validating its performance on the ground and from aircraft. LSDpol is based on a spatially varying quarter-wave retarder that is implemented with a patterned liquid-crystal. It is the first optical element to maximize the polarimetric sensitivity. Since this pattern as well as the entrance slit of the spectrograph have to be imaged onto the detector, the slit serves as the aperture, and an internal field stop limits the field of view. The retarder's fast axis angle varies linearly along one spatial dimension. A fixed quarter-wave retarder combined with a polarization grating act as the disperser and the polarizing beam-splitter. Circular and linear polarization are thereby encoded at incompatible modulation frequencies across the spectrum, which minimizes the potential cross-talk from linear into circular polarization.Comment: 10 pages, 10 figures, SPIE Proceedings 11443-16

The ETNA mission concept: Assessing the habitability of an active ocean world

Enceladus is an icy world with potentially habitable conditions, as suggested by the coincident presence of a subsurface ocean, an active energy source due to water-rock interactions, and the basic chemical ingredients necessary for terrestrial life. Among all ocean worlds in our Solar System, Enceladus is the only active body that provides direct access to its ocean through the ongoing expulsion of subsurface material from erupting plumes. Here we present the Enceladus Touchdown aNalyzing Astrobiology (ETNA) mission, a concept designed during the 2019 Caltech Space Challenge. ETNA’s goals are to determine whether Enceladus provides habitable conditions and what (pre-) biotic signatures characterize Enceladus. ETNA would sample and analyze expelled plume materials at the South Polar Terrain (SPT) during plume fly-throughs and landed operations. An orbiter includes an ultraviolet imaging spectrometer, an optical camera, and radio science and a landed laboratory includes an ion microscope and mass spectrometer suite, temperature sensors, and an optical camera, plus three seismic geophones deployed during landing. The nominal mission timeline is 2 years in the Saturnian system and ∼1 year in Enceladus orbit with landed operations. The detailed exploration of Enceladus’ plumes and SPT would achieve broad and transformational Solar System science related to the building of habitable worlds and the presence of life elsewhere. The nature of such a mission is particularly timely and relevant given the recently released Origins, Worlds, and Life: A Decadal Strategy for Planetary Science and Astrobiology 2023–2032, which includes a priority recommendation for the dedicated exploration of Enceladus and its habitable potential

Integrated photonic-based coronagraphic systems for future space telescopes

The detection and characterization of Earth-like exoplanets around Sun-like stars is a primary science motivation for the Habitable Worlds Observatory. However, the current best technology is not yet advanced enough to reach the 10^-10 contrasts at close angular separations and at the same time remain insensitive to low-order aberrations, as would be required to achieve high-contrast imaging of exo-Earths. Photonic technologies could fill this gap, potentially doubling exo-Earth yield. We review current work on photonic coronagraphs and investigate the potential of hybridized designs which combine both classical coronagraph designs and photonic technologies into a single optical system. We present two possible systems. First, a hybrid solution which splits the field of view spatially such that the photonics handle light within the inner working angle and a conventional coronagraph that suppresses starlight outside it. Second, a hybrid solution where the conventional coronagraph and photonics operate in series, complementing each other and thereby loosening requirements on each subsystem. As photonic technologies continue to advance, a hybrid or fully photonic coronagraph holds great potential for future exoplanet imaging from space.Comment: Conference Proceedings of SPIE: Techniques and Instrumentation for Detection of Exoplanets XI, vol. 12680 (2023

Visible extreme adaptive optics on extremely large telescopes: Towards detecting oxygen in Proxima Centauri b and analogs

Looking to the future of exo-Earth imaging from the ground, core technology developments are required in visible extreme adaptive optics (ExAO) to enable the observation of atmospheric features such as oxygen on rocky planets in visible light. UNDERGROUND (Ultra-fast AO techNology Determination for Exoplanet imageRs from the GROUND), a collaboration built in Feb. 2023 at the Optimal Exoplanet Imagers Lorentz Workshop, aims to (1) motivate oxygen detection in Proxima Centauri b and analogs as an informative science case for high-contrast imaging and direct spectroscopy, (2) overview the state of the field with respect to visible exoplanet imagers, and (3) set the instrumental requirements to achieve this goal and identify what key technologies require further development.Comment: SPIE Proceeding: 2023 / 12680-6

Assessment of the effectiveness of two different orthodontic retention protocols

Introduction: The main goal of orthodontic retention is to keep the teeth in their corrected positions. Fixed or removable retainers are the most common types of retainers used during the retention phase. For the maxilla, various types of retainers have been described, including the vacuum-formed retainers and Hawley retainers. Fixed retainers are used for the lower jaw. Aim: The aim of the present study was to assess the retention characteristics of Hawley retainers, vacuum-formed retainers, and fixed retainers in preserving dental arch dimensions and tooth alignment. Materials and methods: Seventy subjects were examined and distributed into two retention groups. One of the groups received maxillary Hawley retainers and bonded retainers in the mandible. The other group received maxillary vacuum-formed retainers and bonded retainers in the mandible. The mean retention period was two years. Maxillary and mandibular casts were analyzed at pretreatment, debonding, and two years in retention. The assessed measurements were the arch length, intercanine width, interpremolar width, intermolar width and Little’s irregularity index. Results: Vacuum-formed retainers maintained maxillary anterior teeth alignment more effectively than Hawley retainers did. No differences in transversal dimensions were found between the two retention protocols. Hawley retainers showed superior retention characteristics in maxillary arch length preservation compared to vacuum-formed retainers. Even with bonded retainers, relapse could still happen. All measured variables showed a tendency to relapse to the pretreatment values in the two groups. Conclusions: Vacuum-formed retainer maintained maxillary incisor position more effectively than Hawley retainers did. No differences were observed in the transversal dimensions between the two groups. A greater decrease in the mandibular intermolar width was measured between T1 and T2 in both groups where bonded retainers were used

Design of the life signature detection polarimeter LSDpol

Many biologically produced chiral molecules such as amino acids and sugars show a preference for left or right handedness (homochirality). Light reflected by biological materials such as algae and leaves therefore exhibits a small amount of circular polarization that strongly depends on wavelength. Our Life Signature Detection polarimeter (LSDpol) is optimized to measure these signatures of life. LSDpol is a compact spectropolarimeter concept with no moving parts that instantaneously measures linear and circular polarization averaged over the field of view with a sensitivity of better than 10-4. We expect to launch the instrument into orbit after validating its performance on the ground and from aircraft. LSDpol is based on a spatially varying quarter-wave retarder that is implemented with a patterned liquid-crystal. It is the first optical element to maximize the polarimetric sensitivity. Since this pattern as well as the entrance slit of the spectrograph have to be imaged onto the detector, the slit serves as the aperture, and an internal field stop limits the field of view. The retarder's fast axis angle varies linearly along one spatial dimension. A fixed quarter-wave retarder combined with a polarization grating act as the disperser and the polarizing beam-splitter. Circular and linear polarization are thereby encoded at incompatible modulation frequencies across the spectrum, which minimizes the potential cross-talk from linear into circular polarization.</p

Design of the life signature detection polarimeter LSDpol

Many biologically produced chiral molecules such as amino acids and sugars show a preference for left or right handedness (homochirality). Light reflected by biological materials such as algae and leaves therefore exhibits a small amount of circular polarization that strongly depends on wavelength. Our Life Signature Detection polarimeter (LSDpol) is optimized to measure these signatures of life. LSDpol is a compact spectropolarimeter concept with no moving parts that instantaneously measures linear and circular polarization averaged over the field of view with a sensitivity of better than 10-4. We expect to launch the instrument into orbit after validating its performance on the ground and from aircraft. LSDpol is based on a spatially varying quarter-wave retarder that is implemented with a patterned liquid-crystal. It is the first optical element to maximize the polarimetric sensitivity. Since this pattern as well as the entrance slit of the spectrograph have to be imaged onto the detector, the slit serves as the aperture, and an internal field stop limits the field of view. The retarder's fast axis angle varies linearly along one spatial dimension. A fixed quarter-wave retarder combined with a polarization grating act as the disperser and the polarizing beam-splitter. Circular and linear polarization are thereby encoded at incompatible modulation frequencies across the spectrum, which minimizes the potential cross-talk from linear into circular polarization.Astrodynamics & Space Mission