- Keywords
- FE Analýza,
- MeSH
- Models, Anatomic MeSH
- Biometry methods instrumentation MeSH
- Humans MeSH
- Joint Instability MeSH
- Movement MeSH
- Prospective Studies MeSH
- Joint Prosthesis MeSH
- Range of Motion, Articular MeSH
- Temporomandibular Joint * anatomy & histology physiology growth & development MeSH
- Check Tag
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
The optimal light dose, heat generation, consequent heat spread and an accurate thermal damage model, are key components of effective laser therapies. Recent advances in nanotechnology offer numerous possibilities on how to increase the efficacy of hyperthermia for tumour treatments. Gold nanoparticles are a promising candidate towards the achievement of this goal owing to their properties for efficiently converting light to heat. In this review, we summarise the numerical tools that are available for theoretical studies of gold-nanoparticle-mediated photo-thermal therapy. The processes that occur in the treatments based on light propagation inside biological tissues and the subsequent temperature distributions are considered first, followed by evaluation of the thermal damage. The fundamental ideas underlying the presented methods are described in addition to their applications in photo-thermal therapy and its effects. The descriptions of extensively used tools for the characterisation of nanoparticles across multiple research fields are also presented for estimating the electromagnetic properties of gold nanoparticles (e.g. discrete dipole approximations, finite-difference time-domain simulations), the Monte Carlo model of light propagation in biological tissues, and the Pennes' bio-heat equation. In addition, the Arrhenius damage evaluation and the cumulative effective minutes normalisation methods are described. Finally, recent in vivo and in vitro results from the rapidly growing field of nanomedicine are presented.
PURPOSE OF THE STUDY In developing new or modifying the existing surgical treatment methods of spine conditions an integral part of ex vivo experiments is the assessment of mechanical, kinematic and dynamic properties of created constructions. The aim of the study is to create an appropriately validated numerical model of canine cervical spine in order to obtain a tool for basic research to be applied in cervical spine surgeries. For this purpose, canine is a suitable model due to the occurrence of similar cervical spine conditions in some breeds of dogs and in humans. The obtained model can also be used in research and in clinical veterinary practice. MATERIAL AND METHODS In order to create a 3D spine model, the LightSpeed 16 (GE, Milwaukee, USA) multidetector computed tomography was used to scan the cervical spine of Doberman Pinscher. The data were transmitted to Mimics 12 software (Materialise HQ, Belgium), in which the individual vertebrae were segmented on CT scans by thresholding. The vertebral geometry was exported to Rhinoceros software (McNeel North America, USA) for modelling, and subsequently the specialised software Abaqus (Dassault Systemes, France) was used to analyse the response of the physiological spine model to external load by the finite element method (FEM). All the FEM based numerical simulations were considered as nonlinear contact statistic tasks. In FEM analyses, angles between individual spinal segments were monitored in dependence on ventroflexion/ /dorziflexion. The data were validated using the latero-lateral radiographs of cervical spine of large breed dogs with no evident clinical signs of cervical spine conditions. The radiographs within the cervical spine range of motion were taken at three different positions: in neutral position, in maximal ventroflexion and in maximal dorziflexion. On X-rays, vertebral inclination angles in monitored spine positions were measured and compared with the results obtain0ed from FEM analyses of the numerical model. RESULTS It is obvious from the results that the physiological spine model tested by the finite element method shows a very similar mechanical behaviour as the physiological canine spine. The biggest difference identified between the resulting values was reported in C6-C7 segment in dorsiflexion (Δφ = 5.95%), or in C4-C5 segment in ventroflexion (Δφ = -3.09%). CONCLUSIONS The comparisons between the mobility of cervical spine in ventroflexion/dorsiflexion on radiographs of the real models and the simulated numerical model by finite element method showed a high degree of results conformity with a minimal difference. Therefore, for future experiments the validated numerical model can be used as a tool of basic research on condition that the results of analyses carried out by finite element method will be affected only by an insignificant error. The computer model, on the other hand, is merely a simplified system and in comparison with the real situation cannot fully evaluate the dynamics of the action of forces in time, their variability, and also the individual effects of supportive skeletal tissues. Based on what has been said above, it is obvious that there is a need to exercise restraint in interpreting the obtained results. Key words: cervical spine, kinematics, numerical modelling, finite element method, canine.
- MeSH
- Cervical Vertebrae diagnostic imaging physiology MeSH
- Tomography, X-Ray Computed MeSH
- Computer Simulation * MeSH
- Dogs MeSH
- Range of Motion, Articular * physiology MeSH
- Imaging, Three-Dimensional MeSH
- Animals MeSH
- Check Tag
- Dogs MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Comparative Study MeSH
In sperms of infertile men is higher incidence of chromosome aneuploidy. Consequently for embryos developed from these sperms PGD is indicated. Material and methods: In our laboratory were made 331 PGD cycles. 25 of them were counted among group of indication, in which embryos were fertlized with sperm after TESA. PGD was performed on blastomeres from three-day old embryo in two hybridisation cycles. During this procedure we evaluated 8 chromosomes (13, 15, 16, 18, 21, 22, X, Y). Results: Total mean age of patients with spermatogenic failure was 32.24. This group contained 25 couples and 184 embryos were evaluated. From this amount 75 preimplantation embryos did not show numerical aberrations for detected chromosomes and 22 of them were transferred. 31.8 % patients were pregnant (this number related to embryotransferr). On the other side more than 59 % investigated blastomeres showed a numerical chromosomal abnormality. Monosomy chromosome 16 and aneuploidy of sex chromosomes were observed the most frequently. Conclusions: The incidence of aneuploidies in sperm after TESA should correlate with incidence of genetic abnormalities in embryo. Our results are similar to literature, where sex chromosomes aneuploidies the most frequently occur in sperms after TESA. In these studies the chromosome 16 was not analysed. The higher incidence of monosomy of this chromosome can be caused by low number of evaluated blastomeres.
Developments in environmental modelling ; vol. 20
2nd english ed. xv, 853 s.
Cíl: Při narození existuje komunikace mezi pravou a levou komorou, tato komunikace však po narození zmizí. V některých případech komunikace přetrvává a komory nemohou fungovat nezávisle na sobě. Tato abnormalita působí problémy, například hypertenzi, a komplikuje práci srdečních chlopní. Cílem této studie bylo analyzovat změny v napětí a deformaci stěny způsobené umístěním záplaty na junkci a zajištění optimalizované geometrie záplaty. Metody: Pro tento účel byly metodou konečných prvků (finite element, FE) vypracovány modely dvou typů kruhových a eliptických záplat se shodnými materiálovými vlastnostmi, následně byly vypočítány a srovnány výsledky těchto dvou různých geometrií. Výsledky: Při stejných hraničních a zátěžových podmínkách výsledky ukázaly, že eliptická záplata je spojena s menším napětím stěny a je bezpečná pro použití v komorách ve srovnání s kruhovou záplatou. Závěr: Výsledky této studie mají význam nejen pro stanovení míry napětí a deformace stěny po našití záplaty, ale i pro zajištění optimalizované geometrie spojené s nižší incidencí komplikací.
Purpose: At birth, there is a communication between the right and left ventricles, but this communication disappears after the birth. In some cases, the communication has been continued and ventricles cannot operate independently on each other. This abnormal communication causes problems, such as hypertension and heart valves complications. The purpose of this study was to analyse alterations in stress and strain caused by placement of a patch on junction and offering optimized geometry for it. Methods: For this purpose, finite element (FE) models of two types of circular and elliptical patches with the same material properties were established and the results of these two different geometries were calculated and compared. Results: Considering the same boundary and loading conditions, the results revealed that the elliptical patch triggers less stresses and is safe to use in ventricle compared to the circular one. Conclusion: The results of the concurrent study have implications not only for understanding of the magnitudes of the stress and strain because of a patch but also for providing an optimized geometry which brings about less complications.
Cílem studie je ukázat, že nově vyvinutá metoda automatické analýzy EEG dokáže rozpoznat abnormální fenomény novorozeneckého EEG a je schopna závažnost odchylky zhodnotit kvantitativně. Analyzovány byly digitální EEG záznamy 36 novorozenců, u nichž bylo EEG vyšetření indikováno z klinických důvodů. Pětiminutové vzorky EEG aktivity ze standardizovaného behaviorálního stavu byly za použití počítačem podporované čtyřstupňové analýzy popsány 312 číselnými položkami, informujícími o amplitudě, výkonu v pěti frekvenčních pásmech, o tvaru signálu a o jeho stálosti či proměnlivosti. Každá z těchto položek byla automaticky porovnána s normativním údajem, získaným vyšetřením 21 zdravých donosených novorozenců, a testována, liší-li se od normy o jednu či o dvě směrodatné odchylky. Počet pacientových položek lišících se od normy byl úměrný závažnosti jeho abnormality. Orientační porovnání výsledků automatické a vizuální analýzy pacientských elektroencefalogramů osvědčilo dobrou shodu. Metoda je příslibem pro klinickou praxi, neboť může významně přispět jak ke zrychlení, tak i k objektivizaci hodnocení novorozeneckého EEG.
The study aims to demonstrate that the newly developed method of automated EEG analysis can detect abnormal phenomena in the neonatal EEG and can quantify the severity of the deviation from the norm. EEG records from 36 neonates with clinically indicated EEG examination were analyzed. Five-minutes samples of EEG activity during a standardized behavioral state were processed using a computer-supported four-stage analysis and described with 312 numerical items, providing the information on amplitude, power in five frequency bands, on signal shape and its stability or variability. Each of these items was automatically compared to normative data acquired from the examination of 21 healthy, full term neonates and tested whether it differs by one or two standard deviations from the norm. The number of patient's items differing from the norm was proportional to the severity of their abnormality. A cursory comparison of the results of automatic and visual analyses of patienť EEG records showed good agreement. The method shows promise for the clinical practice, where it can significantly contribute to both acceleration and greater objectivity of neonatal EEG assessment.
Turing's diffusion-driven instability for the standard two species reaction-diffusion system is only achievable under well-known and rather restrictive conditions on both the diffusion rates and the kinetic parameters, which necessitates the pairing of a self-activator with a self-inhibitor. In this study we generalize the standard two-species model by considering the case where the reactants can bind to an immobile substrate, for instance extra-cellular matrix, and investigate the influence of this dynamics on Turing's diffusion-driven instability. Such systems have been previously studied on the grounds that binding of the self-activator to a substrate may effectively reduce its diffusion rate and thus induce a Turing instability for species with equal diffusion coefficients, as originally demonstrated by Lengyel and Epstein (1992) under the assumption that the bound state dynamics occurs on a fast timescale. We, however, analyse the full system without any separation of timescales and demonstrate that the full system also allows a relaxation of the standard constraints on the reaction kinetics for the Turing instability, increasing the type of interactions that could give rise to spatial patterning. In particular, we show that two self-activators can undertake a diffusively driven instability in the presence of a binding immobile substrate, highlighting that the interactions required of a putative biological Turing instability need not be associated with a self-activator-self-inhibitor morphogen pair.
The aim of this article is 3D analysis of the temporomandibular joint (TMJ) patient, who underwent surgery, during which the right TMJ was resected along with the ramus of mandible and consequently the joint was reconstructed with subtotal replacement. The main goal is to give a suitable formulation of mathematical model, which describes the changes of stresses in TMJ incurred after the surgery. The TMJ is a complex, sensitive and highly mobile joint which works bilaterally so each side influences the contralateral joint and because of this the distribution of the stresses is changed in the healthy joint as well. Detailed knowledge about function these are necessary for clinical application of temporomandibular joint prosthesis and also help us estimate the lifetime of the prosthesis a possibilities of alteration in the contra lateral joint components. The geometry for the 3D models is taken from the CT scan date and its numerical solution is based on the theory of semi-coercive unilateral contact problems in linear elasticity. This article provides medical part with case report, discretion of treatment, than the methods of mathematical modeling and his possibilities are described and finally results are reported.
- MeSH
- Finite Element Analysis MeSH
- Models, Anatomic MeSH
- Biomechanical Phenomena MeSH
- Jaw Cysts pathology radiography surgery MeSH
- Humans MeSH
- Mandibular Prosthesis MeSH
- Temporomandibular Joint Disorders pathology radiography surgery MeSH
- Tomography, X-Ray Computed statistics & numerical data MeSH
- Computer Simulation MeSH
- Aged MeSH
- Temporomandibular Joint physiology physiopathology surgery MeSH
- Imaging, Three-Dimensional methods MeSH
- Check Tag
- Humans MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Case Reports MeSH
- Research Support, Non-U.S. Gov't MeSH
Motivation: The NCBI database contains mitochondrial DNA (mtDNA) genomes from numerous species. We investigated the presence and locations of inverted repeat sequences (IRs) in these mtDNA sequences, which are known to be important for regulating nuclear genomes. Results: IRs were identified in mtDNA in all species. IR lengths and frequencies correlate with evolutionary age and the greatest variability was detected in subgroups of plants and fungi and the lowest variability in mammals. IR presence is non-random and evolutionary favoured. The frequency of IRs generally decreased with IR length, but not for IRs 24 or 30 bp long, which are 1.5 times more abundant. IRs are enriched in sequences from the replication origin, followed by D-loop, stem-loop and miscellaneous sequences, pointing to the importance of IRs in regulatory regions of mitochondrial DNA. Availability and implementation: Data were produced using Palindrome analyser, freely available on the web at http://bioinformatics.ibp.cz. Contact: vaclav@ibp.cz. Supplementary information: Supplementary data are available at Bioinformatics online.
