The purpose of the research was to analyse the injuries of primary school children in the framework of organised sports activities at school and in clubs or associations, and in leisure time without ...professional guidance.
We surveyed 631 participants, of which there were 282 boys and 349 girls from eight Slovenian primary schools. Frequencies were calculated and a Chi-square test was performed.
In physical education (PE) at school, 32% of the participants were injured in one school year, and there were no statistically significant differences in the number of injuries according to sex (p=0.18) and age (p=0.12). Most injuries were recorded in the lower extremities (50%), in the form of wounds. The participants were injured less often in PE at school than in a club or association, and more often than in their leisure time. The participants were absent from PE classes for longer after an injury in a club or association than in PE, while no significant differences in absences after injury were found. At school, the participants were most often injured in ball games, boys in football (43%) and girls in volleyball (19%). In activities in a club or association, we recorded the most injuries in boys in martial arts (18%) and dance for girls (19%). In their leisure time, boys suffered the most injuries from football (26%) and cycling, while girls suffered the most from running and rollerblading.
In the last ten years, the number of injuries in PE has increased in Slovenia. Based on the obtained results, we propose measures to reduce injuries and thus encourage more sports activities among children and adolescents, while ensuring their safety.
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•Laser ablation enables controlled biodegradability of Fe–Mn alloy.•Increased corrosion appears due to laser-induced high-temperature oxides.•XPS reveals mechanism for ...biodegradability via shift in surface Fe/Mn ratio to Mn.•Corrosion rate for laser-textured Fe–Mn is 10-times higher as for Fe.•Laser-triggered corrosion is self-driven leading to biodegradability of bulk.
In this study we report the influence of laser ablation on the controlled biodegradability of a Fe–Mn alloy developed for medical implants. After texturing by a nanosecond Nd:YAG laser, the surface expressed extreme super-hydrophilic wetting properties, since laser ablation led to micro-channels and chemical modification resulting in nanostructured metal oxides. The influence of functionalized surface properties on corrosion behavior was examined on molecular level by using X-ray photoelectron spectroscopy. Results reveal that the oxide layer after the laser texturing of Fe–Mn alloy consists mainly of Fe2O3 and FeO, with the content of Mn in the oxide layer being significantly higher than in the bulk. The results of the electrochemical measurements clearly demonstrate the superior biodegradability of the Fe–Mn alloy samples functionalized by laser ablation. Here, the laser-triggered corrosion is self-driven by further production of corrosion products that leads to biodegradability of the whole sample.
Laser-enhanced irrigation of complex root canals appears to be a very promising technique to improve the outcome of root canal treatment. This applies, in particular, if the technique can be ...effective at very low laser energies in irrigating not only the main canal but also the small lateral canals. This is important in order to avoid potential undesirable effects at higher laser energies such as temperature increase, dentin ablation, or extrusion of irrigating solution beyond the apical foramen. An improved understanding of the role of laser parameters, such as laser wavelength and pulse duration, in irrigation of lateral canals is therefore desired in order to optimize treatment efficacy. The influence of laser wavelength and pulse duration on cavitation phenomena was studied using shadow photography and a method of measuring fluid flow in lateral canals based on tracking of movements of small air bubbles naturally forming in liquid as a result of laser agitation. A simulated model of a root canal including a narrow lateral canal designed to represent typical root canal morphology was used for the water flow measurements. The following three laser wavelengths with relatively high absorption in water were studied: Er:YAG (2.94 μm), Er,Cr:YSGG (2.73 μm), and Nd:YAP (1.34 μm). Among the three wavelengths studied, the Er:YAG laser wavelength was found to be the most effective in formation of cavitation bubbles and in generating fluid motions within narrow lateral canals. A comparison between the shadow photography and fluid motion data indicates that it is the bubble's radius and not the bubble's volume that predominantly influences the fluid motion within lateral canals. Based on the results of our study, it appears that effective minimally invasive laser-assisted irrigation can be performed with low Er:YAG laser pulse energies below 10 mJ.
The irradiation of metallic surfaces by high-fluence laser pulses in an oxygen-containing atmosphere inevitably modifies the surface topography, chemistry, and wettability. These modifications ...significantly influence cell-surface interactions and, consequently, surface biocompatibility. We investigate how surface texturing by high-fluence nanosecond laser pulses from a Nd:YAG laser (wavelength of 1064 nm) influences cell adhesion and morphology with the aim of assessing its impact on initial cell behaviour. Quantitative and qualitative analysis of osteosarcoma cell adhesion, viability, and cell morphology were evaluated after 24-hour exposure to non-treated and laser-textured stainless-steel (AISI 316L) surfaces by fluorescent and scanning electron microscopy. The results reveal that this, initial interaction between the cells and the laser-textured surfaces leads to round shaped cells with a smaller footprint. Contrarily, on the non-processed stainless-steel and control-glass surfaces the polygonal, highly elongated, and flattened cells are observed. The cells on the laser-textured surfaces are less dendritic, with short tubular protrusions and an overexpression of extracellular vesicles, which are rarely found on non-treated and control samples. This likely happens due to the formation of nanostructured, high-temperature oxides that are induced by laser ablation. The analysis by X-ray photoelectron spectroscopy reveals that the laser-textured stainless-steel surfaces contain Cr hexavalent oxide, which is more toxic than the native oxide layer on the non-processed samples.
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•Laser texturing induces hierarchically micro- and nanostructured metal oxides.•Thick oxides and increased amount of cytotoxic Cr hexavalent oxide are identified.•Cells become round shaped with shorter tubular protrusions and abundant exosomes.•High-fluence laser texturing of SS in air decreases surface biocompatibility.•After 24 h of growth on textured surfaces, cell viability was not affected.
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