Ústav mechaniky těles, mechatroniky a biomechaniky
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- ItemCustomized protective palatal obturator for intubation in newborns in cleft lip surgery: a randomized controlled trial(2025-09-22) Marcián, Petr; Borák, LiborBackgroundOrofacial clefts are common congenital malformations, affecting both facial aesthetics and function. Intubation in newborns with cleft lip and palate is challenging and carries a high risk of oral tissue damage. This study investigates the use of a customized protective palatal obturator (CPPO) to improve intubation safety and reduce tissue injury during cleft lip surgery.MethodsA single-center, randomized neonatal sub-study was conducted, including 55 newborns who underwent cleft lip surgery. Patients were randomized into an intervention group (CPPO use) and a control group (standard intubation without CPPO). The primary aim was to evaluate the degree of oral tissue injury during intubation, its severity, and location, in both groups, secondary aims included laryngoscopy image during intubation (modified Cormack-Lehane scoring system), intubation time, and attempts, number of intubations attempts and anesthesiologic complication during intubation. This study was registered on www.clinicaltrials.gov (ClinicalTrials.gov Identifier: NCT04422847 and NCT04422964).ResultsNo tissue damage occurred in the CPPO group, while the control group had a 21.4% incidence of tissue injury (p = .023). Secondary outcomes showed no statistically significant differences between groups for intubation time or the number of intubation attempts. Difficult intubation was less frequent in the CPPO group (40.7%) compared to the control group (50%), though this difference was not statistically significant.ConclusionThe CPPO significantly reduces the risk of tissue damage during intubation in newborns undergoing cleft lip surgery, without increasing intubation time or attempts. It is particularly beneficial for severe clefts, and its use may facilitate safer airway management in these high-risk patients.
- ItemFull-Range Optical Imaging of Planar Collagen Fiber Orientation Using Polarized Light Microscopy(Hindawi, 2021-11-28) Turčanová, Michaela; Hrtoň, Martin; Viewegh, Petr; Novák, Kamil; Hermanová, Markéta; Bednařík, Zdeněk; Polzer, Stanislav; Burša, JiříA novel method for semiautomated assessment of directions of collagen fibers in soft tissues using histological image analysis is presented. It is based on multiple rotated images obtained via polarized light microscopy without any additional components, i.e., with just two polarizers being either perpendicular or nonperpendicular (rotated). This arrangement breaks the limitation of 90° periodicity of polarized light intensity and evaluates the in-plane fiber orientation over the whole 180° range accurately and quickly. After having verified the method, we used histological specimens of porcine Achilles tendon and aorta to validate the proposed algorithm and to lower the number of rotated images needed for evaluation. Our algorithm is capable to analyze 5·105 pixels in one micrograph in a few seconds and is thus a powerful and cheap tool promising a broad application in detection of collagen fiber distribution in soft tissues.
- ItemPoint defects stabilise cubic Mo-N and Ta-N(IOP PUBLISHING LTD, 2016-08-22) Koutná, Nikola; Holec, David; Svoboda, Ondřej; Klimashin, Fedor; Mayrhofer, PaulWe employab initio calculations to investigate energetics of point defects in metastable rocksalt cubic Ta-N and Mo-N. Our results reveal a strong tendency to off-stoichiometry, i.e. defected structures are predicted to be more stable than perfect ones with 1:1 metal-to-nitrogen stoichiometry, in agreement with previous literature reports. While Ta-N significantly favours metal vacancies, Mo-N exhibits similar energies of formation regardless of the vacancy type (V Mo , V N ) as long as their concentration is below ?15at.\% . The overall lowest energy of formation were obtained for Ta 0.78 N and Mo 0.91 N , which are hence predicted to be the most stable compositions. To account for various experimental condition during synthesis, we further evaluated the phase stability as a function of chemical potential of individual species. The proposed phase diagrams reveal four stable compositions, Mo 0.84 N , Mo 0.91 N , MoN 0.69 and MoN 0.44 , in the case of Mo-N and nine stable compositions in the case of Ta-N indicating the crucial role of metal under-stoichiometry, since Ta 0.75 N and Ta 0.78 N significantly dominate the diagram. These results are important for understanding and designing experiments using non-equilibrium deposition techniques. Finally, we discuss a role of defects ordering and estimate a cubic lattice parameter as a function of a defect contents.
- ItemActive Elbow Orthosis(InTech Europe, 2014-09-08) Ripel, Tomáš; Krejsa, Jiří; Hrbáček, Jan; Čižmář, IgorThis paper presents a novel approach to the design of a motorized rehabilitation device – active elbow orthosis (AEO) – inspired by the principles of robotic exoskeletons. The device is currently designed for the elbow joint, but can be easily modified for other joints as well. AEO determines the motion activity of the patient using a strain gauge and utilizes this measurement to control the actuator that drives the forearm part of the orthosis. Patient activity level is related to a free arm measurement obtained via a calibration procedure prior to the exercise. A high-level control module offers several types of exercises mimicking the physiotherapist. The device was successfully verified by tests on a number of patients, resulting in extended range of elbow-joint motion.
- ItemInfluence of variable stress ratio during train operation on residual fatigue lifetime of railway axles(Elsevier, 2016-01-01) Pokorný, Pavel; Náhlík, Luboš; Hutař, PavelRailway axles are subjected to cyclic loading, which could lead to fatigue failure. Therefore, it is desired to know residual fatigue lifetime of railway axles to ensure safe operation of trains. Because of detection of relatively small fatigue cracks is not guaranteed an estimation of residual fatigue lifetime is based on damage tolerance approach. The acting stress ratio is variable due to variable amplitude loading and load caused by existence of press-fitted wheel in the vicinity of assumed crack. The contribution is focused on influence of variable stress ratio in EA4T steel on residual fatigue lifetime of railway axles. The influence of stress intensity factor on fatigue crack propagation rate was experimentally evaluated for three different stress ratios, which correspond to operation conditions. Two different expressions of fatigue crack propagation rate were used and mutually compared to show influence of the stress ratio on residual fatigue lifetime of structure made of EA4T steel. The first expression considers stress intensity factor range (respecting stress ratio R) and the second one uses maximal value of the stress intensity factor. The paper shows ability of both expressions to describe experimental data obtained under different stress ratios and their influence on estimated residual fatigue lifetime values. The results obtained contribute to the better estimation of residual fatigue lifetime of railway axles and generally to the safer rail transportation. Copyright (C) 2016 The Authors. Published by Elsevier B.V.