PURPOSE OF THE STUDY The aim of the study was to assess the accuracy of axis deformity correction achieved by high-tibial valgus osteotomy either without or with a computer-assisted kinematic navigation system, on the basis of comparing the planned and the achieved frontal axis of the leg. Comparisons of mechanical axis deviation were made using both pre- and post-operative measurements with the planning software and intra-operative measurements with the navigation system before and after osteotomy. In addition, the aim was to test the hypothesis that the use of 3D navigation, as compared with 2D navigation, would help reduce changes in the tibial plateau slope. MATERIAL AND METHODS In the period 2008-2011, high-tibial osteotomy was performed in 68 patients. Twenty-one patients (group 1) underwent osteotomy without the use of navigation and 47 patients (group 2) had osteotomy with a computer-assisted navigation system (32 with 2D navigation and 15 with 3D navigation). Using the planning software, the mechanical leg axis before and after surgery and the anatomical dorsal proximal tibial angle in the sagittal plane were assessed. Medial opening-wedge high-tibial valgus osteotomy was carried out in all patients. When using 2D navigation, the mechanical leg axis was measured intra-operatively before osteotomy and then after osteosynthesis which included a simulated axial load of the heel. When using 3D navigation, the procedure was identical and furthermore involved a measurement of the tibial plateau slope obtained with an additional probe in the proximal fragment. The results were characterised using descriptive statistics and their significance was evaluated using the Mann-Whitney U test and Wilcoxon's test, with the level of significance set at p < 0.05. RESULTS In group 1, osteotomy resulted in good correction of the mechanical axis in nine patients (43%), inadequate correction in nine (43%) and overcorrection and three (14%) patients. In group 2 with the use of navigation, accurate correction of the mechanical leg axis was achieved in 24 patients (51%), undercorrection was recorded in 21 (45%) and overcorrection in two (4%) patients. The difference in outcomes between the two groups was not statistically significant (p = 0.73). The average correction of the mechanical axis based on comparing measurements on pre- and post-operative radiographs was 9.1 degrees (range, 5-27 degrees); the average correction of the axis visualised intra-operatively was 8.7 degrees (range, 4-27 degrees). The difference was not significant (p = 0.1615) and confirmed our hypothesis that the accuracy of measuring the mechanical axis was not influenced by the method used. The average change in the dorsal slope of the tibial plateau following osteotomy without navigation was 0.9 degrees (range, -8.9 to 9.0 degrees) and that after osteotomy with intra-operative visualisation of the proximal tibial slope was 0.3 degrees (range, -4 to 4 degrees). This difference was not statistically significant (p = 0.813). DISCUSSION A good clinical outcome of high-tibial valgus osteotomy depends on achieving accurate correction of the mechanical leg axis with partial load transfer to the lateral compartment of the knee. CONCLUSIONS Although the number of cases with good correction was slightly higher in the patients undergoing osteotomy with navigation, the difference was not significant. Intra-operative visualisation of the mechanical axis proved sufficiently accurate on comparison with the pre-operative planning based on weight-bearing radiography of the leg. A simulated axial load of the heel included in the kinematic navigation system does not sufficiently correspond to normal weight-bearing and therefore an undercorrection of the deformity might occur. Using 3D navigation had no marked effect on a change in the slope of the tibial plateau.
- MeSH
- Surgery, Computer-Assisted * MeSH
- Adult MeSH
- Genu Valgum surgery MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Osteotomy * MeSH
- Aged MeSH
- Tibia surgery MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Aged MeSH
- Female MeSH
- Publication type
- English Abstract MeSH
- Journal Article MeSH
The human body involves a large number of systems subjected to contact stresses and thus experiencing wear and degradation. The limited efficacy of existing solutions constantly puts a significant financial burden on the healthcare system, more importantly, patients are suffering due to the complications following a partial or total system failure. More effective strategies are highly dependent on the availability of advanced functional materials demonstrating excellent tribological response and good biocompatibility. In this article, we review the recent progress in implementing two-dimensional (2D) materials into bio-applications involving tribological contacts. We further summarize the current challenges for future progress in the field.
- MeSH
- Humans MeSH
- Friction * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
In response to the growing need for development of modern biomaterials for applications in regenerative medicine strategies, the research presented here investigated the biological potential of two types of polymer nanocomposites. Graphene oxide (GO) and partially reduced graphene oxide (rGO) were incorporated into a poly(ε-caprolactone) (PCL) matrix, creating PCL/GO and PCL/rGO nanocomposites in the form of membranes. Proliferation of osteoblast-like cells (human U-2 OS cell line) on the surface of the studied materials confirmed their biological activity. Fluorescence microscopy was able to distinguish the different patterns of interaction between cells (depending on the type of material) after 15 days of the test run. Raman micro-spectroscopy and two-dimensional correlation spectroscopy (2D-COS) applied to Raman spectra distinguished the nature of cell-material interactions after only 8 days. Combination of these two techniques (Raman micro-spectroscopy and 2D-COS analysis) facilitated identification of a much more complex cellular response (especially from proteins) on the surface of PCL/GO. The presented approach can be regarded as a method for early study of the bioactivity of membrane materials.
- MeSH
- Graphite * pharmacology chemistry MeSH
- Humans MeSH
- Osteoblasts MeSH
- Polyesters chemistry MeSH
- Polymers MeSH
- Spectrum Analysis, Raman MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Cíl: Zjistit míru vzájemné zastupitelnosti 3 různých digitálních rentgenogramů pro určování polohy retinovaných horních špičáků – kefalometrického snímku, CBCT a kefalometrického snímku generovaného z CBCT pomocí určení opakovatelnosti a reprodukovatelnosti měření pozice retinovaného zubu. Materiál a metodika: Soubor tvořili pacienti ortodontického oddělení Kliniky zubního lékařství LF UP a FN Olomouc a Stomatologické kliniky UK a FN Hradec Králové. Z nich byli vybráni pacienti s retencí horního špičáku, kde byl před léčbou indikován kefalometrický a posléze i CBCT snímek, celkem 43 pacientů s 51 palatinálně retinovanými špičáky. Na kefalometrickém snímku, CBCT a kefalometrickém snímku generovaném z CBCT byla měřena vzdálenost hrotu špičáku a úhel dlouhé osy retinovaného špičáku k okluzní rovině. Ke zjištění spolehlivosti měření na digitálních rentgenových snímcích a ke zjištění míry vzájemné zastupitelnosti digitálních rentgenogramů zhotovených třemi různými způsoby byla hodnocena opakovatelnost a reprodukovatelnost měření. Výsledky: Byla prokázána dobrá míra opakovatelnosti určení polohy špičáků pro všechna tři rentgenová zobrazení. Reprodukovatelnost měření polohy retinovaných špičáků určením vertikální vzdálenosti hrotu vůči okluzní rovině byla dobrá, ale výsledky měření reprodukovatelnosti sklonu dlouhé osy špičáku k okluzní rovině se u jednotlivých rentgenových snímků lišily. Měření dále prokázala velkou soustavnou odchylku (bias) naměřených hodnot u úhlových měření mezi CBCT a digitálními kefalometrickými snímky nebo počítačově generovanými z CBCT snímků. Závěr: Měření sklonu dlouhé osy špičáku k okluzní rovině není možné volně zaměnit mezi CBCT a 2D kefalometrickými snímky. Vertikální vzdálenost hrotu špičáku od okluzní roviny je jediným parametrem, u kterého je možné měření na 2D a 3D rentgenech vzájemně zaměnit.
Aims: We wanted to establish the degree of mutual substitutability of 3 different digital radiograms in defining location of impacted upper canines – cephalogram, CBCT, and cephalogram generated from CBCT, with the help of repeatability and reproducibility of measurement of an impacted tooth location. Material and method: The sample included patients of orthodontic departments of the Institute of Dentistry and Oral Sciences, Faculty of Medicine and Dentistry, Palacky University and University Hospital Olomouc and the Clinic of Stomatology, Charles University and University Hospital Hradec Králové. We selected the patients with impacted upper canine with cephalogram and CBCT taken prior to treatment – 43 patients, 51 palatally impacted canines. The distance between canine cusp and occlusal plane, and angle of a long axis of impacted canine to occlusal plane were measured in cephalograms, CBCTs and in cephalograms generated from CBCT. To establish reliability of mesurement in digital radiographs and mutual substitutability of digital radiograms made by three different techniques repeatability and reproducibility of measurement was evaluated. Results: A good degree of repeatability of identification of canines location was proved in all three radiographic methods. Reproducibility of measurement of impacted canines location by defining vertical distance between canine cusp and occlusal plane was good, however, the results of reproducibility of canine long axis inclination to occlusal plane varied in different types of radiographs. Furthermore, measurements showed a big bias of values of angular measurements between CBCT and digital cephalograms or generated from CBCT scans. Conclusion: Measurement of canine long axis inclination to occlusal plane is different in CBCT and 2D cephalograms. Vertical distance between canine cusp and occlusal plane is the only parameter the measurements of which are substitutable (2D and 3D).
Due to their attractive band gap properties and van der Waals structure, 2D binary chalcogenide materials have been widely investigated in the last decade, finding applications in several fields such as catalysis, spintronics, and optoelectronics. Ternary 2D chalcogenide materials are a subject of growing interest in materials science due to their superior chemical tunability which endows tailored properties to the devices prepared thereof. In the family of AIIBIII2XVI4, ordered ZnIn2S4-like based photocatalytic systems have been studied meticulously. In contrast, reports on disordered phases appear to a minor extent. Herein, a photoelectrochemical (PEC) detector based on the pseudo-binary MnIn2Se4 system is presented. A combination of optical measurements and DFT calculations confirmed that the nature of the bandgap in MnIn2Se4 is indirect. Its performance outclasses that of parent compounds, reaching responsivity values of 8.41 mA W-1. The role of the non-centrosymmetric crystal structure is briefly discussed as a possible cause of improved charge separation of the photogenerated charge carriers.
- Publication type
- Journal Article MeSH
Carbon and its analogous nanomaterials are beneficial for toxic gas sensors since they are used to increase the electrochemically active surface region and improve the transmission of electrons. The present article addresses a detailed investigation on the potential of the monolayer PC3 compound as a possible sensor material for environmentally toxic nitrogen-containing gases (NCGs), namely NH3, NO, and NO2. The entire work is carried out under the frameworks of density functional theory, ab-initio molecular dynamics simulations, and non-equilibrium Green's function approaches. The monolayer-gas interactions are studied with the van der Waals dispersion correction. The stability of pristine monolayer PC3 is confirmed through dynamical, mechanical, and thermal analyses. The mobility and relaxation time of 2D PC3 sensor material with NCGs are obtained in the range of 101-104 cm2 V-1 s-1 and 101-103 fs for armchair and zigzag directions, respectively. Out of six possible adsorption sites for toxic gases on the PC3 surface, the most prominent site is identified with the highest adsorption energy for all the NCGs. Considering the most stable configuration site of the NCGs, we have obtained relevant electronic properties by utilizing the band unfolding technique. The considerable adsorption energies are obtained for NO and NO2 compared to NH3. Although physisorption is observed for all the NCGs on the PC3 surface, NO2 is found to convert into NO and O at 5.05 ps (at 300 K) under molecular dynamics simulation. The maximum charge transfer (0.31e) and work function (5.17 eV) are observed for the NO2 gas molecule in the series. Along with the considerable adsorption energies for NO and NO2 gas molecules, their shorter recovery time (0.071 s and 0.037 s, respectively) from the PC3 surface also identifies 2D PC3 as a promising sensor material for those environmentally toxic gases. The experimental viability and actual implications for PC3 monolayer as NCGs sensor material are also confirmed by examining the humidity effect and transport properties with modeled sensor devices. The transport properties (I-V characteristics) reflect the significant sensitivity of PC3 monolayer toward NO and NO2 molecules. These results certainly confirm PC3 monolayer as a promising sensor material for NO and NO2 NCG molecules.
- MeSH
- Adsorption MeSH
- Nitrogen MeSH
- Electrons MeSH
- Nanostructures * MeSH
- Gases * MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
BACKGROUND: Cardiovascular magnetic resonance (CMR) 2D feature tracking (FT) left ventricular (LV) myocardial strain has seen widespread use to characterize myocardial deformation. Yet, validation of CMR FT measurements remains scarce, particularly for regional strain. Therefore, we aimed to perform intervendor comparison of 3 different FT software against tagging. METHODS: In 61 subjects (18 healthy subjects, 18 patients with chronic myocardial infarction, 15 with dilated cardiomyopathy, and 10 with LV hypertrophy due to hypertrophic cardiomyopathy or aortic stenosis) were prospectively compared global (G) and regional transmural peak-systolic Lagrangian longitudinal (LS), circumferential (CS) and radial strains (RS) by 3 FT software (cvi42, Segment, and Tomtec) among each other and with tagging at 3T. We also evaluated the ability of regional LS, CS, and RS by different FT software vs tagging to identify late gadolinium enhancement (LGE) in the 18 infarct patients. RESULTS: GLS and GCS by all 3 software had an excellent agreement among each other (ICC = 0.94-0.98 for GLS and ICC = 0.96-0.98 for GCS respectively) and against tagging (ICC = 0.92-0.94 for GLS and ICC = 0.88-0.91 for GCS respectively), while GRS showed inconsistent agreement between vendors (ICC 0.10-0.81). For regional LS, the agreement was good (ICC = 0.68) between 2 vendors but less vs the 3rd (ICC 0.50-0.59) and moderate to poor (ICC 0.44-0.47) between all three FT software and tagging. Also, for regional CS agreement between 2 software was higher (ICC = 0.80) than against the 3rd (ICC = 0.58-0.60), and both better agreed with tagging (ICC = 0.70-0.72) than the 3rd (ICC = 0.57). Regional RS had more variation in the agreement between methods ranging from good (ICC = 0.75) to poor (ICC = 0.05). Finally, the accuracy of scar detection by regional strains differed among the 3 FT software. While the accuracy of regional LS was similar, CS by one software was less accurate (AUC 0.68) than tagging (AUC 0.80, p < 0.006) and RS less accurate (AUC 0.578) than the other two (AUC 0.76 and 0.73, p < 0.02) to discriminate segments with LGE. CONCLUSIONS: We confirm good agreement of CMR FT and little intervendor difference for GLS and GCS evaluation, with variable agreement for GRS. For regional strain evaluation, intervendor difference was larger, especially for RS, and the diagnostic performance varied more substantially among different vendors for regional strain analysis.
- MeSH
- Ventricular Function, Left MeSH
- Gadolinium MeSH
- Contrast Media * MeSH
- Humans MeSH
- Magnetic Resonance Imaging, Cine * MeSH
- Magnetic Resonance Spectroscopy MeSH
- Predictive Value of Tests MeSH
- Reproducibility of Results MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
OBJECTIVES: The second-to-fourth digit ratio (2D:4D ratio) can be assumed a valid indicator of sexual differentiation, provided that it is stable once it develops, or eventual changes remain uniform in a respective cohort throughout ontogenesis. The main goal of this study was to determine whether the metacarpal 2M:4M and the digit 2D:4D ratio change during the period of pubertal/adolescent growth. MATERIALS AND METHODS: The metacarpals and digits were measured on radiographs of left hands in the sample of 328 individuals (96 pairs of male and 68 pairs of female twins) from the Wrocław Longitudinal Study of Twins (1967-1983). Five consecutive annual measurements were done for each individual within a 4-year-interval somewhere between 7 and 18 years of age. Age-related changes in both ratios were studied using a set of mixed-effects linear models. Three types of correlation coefficients were used for assessment of stability between repeated measurements at different ages. RESULTS: An overall decrease in the average 2M:4M ratio was observed, attributable to a much larger extent to males than to females. On the contrary, a slight overall increase in the average 2D:4D ratio was observed, attributable to a much larger extent to females than to males. The rank order of the ratios remained highly stable within the monitored period (the correlation coefficient mostly ranged between 0.85 and 0.95). In spite of these findings, we recorded significant intraindividual changes in both ratios. In some individuals the 2D:4D ratio can undergo changes comparable to average sex differences and much higher than average age-related changes. DISCUSSION: Relatively slight overall changes in digit ratio in puberty and adolescence themselves are not inconsistent with the use of the 2D:4D ratio as an indirect marker of prenatal sexual differentiation. Nevertheless, individual changes in the ratios varied substantially in this study and differed from the average trends. Future studies should focus on the nature of interindividual developmental differences in the digit and metacarpal ratios.
- MeSH
- Anthropology, Physical MeSH
- Anthropometry MeSH
- Child MeSH
- Twins MeSH
- Humans MeSH
- Longitudinal Studies MeSH
- Adolescent MeSH
- Sex Characteristics MeSH
- Sexual Maturation MeSH
- Fingers anatomy & histology MeSH
- Puberty physiology MeSH
- Check Tag
- Child MeSH
- Humans MeSH
- Adolescent MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
