26 research outputs found
A "Play and Stay" tenisz utánpótlás program nemzetközi és hazai struktúrájának és működésének összehasonlítása
A „Play and Stay” program bevezetése az egész világon megváltoztatta a 12 éven aluli gyermekek teniszoktatását. A játékalapú és játékos központú
foglalkozások felváltották a korábban alkalmazott,
elsősorban az ütések technikai kivitelezését fejlesztő
oktatási módszereket. A program a gyermekek kompetitív tulajdonságaira épül, azaz a feladatokat versenyszerű környezetbe helyezi, melynek célja a
résztvevők belső motivációjának kialakítása, a tenisz
és a vetélkedés megszerettetése. Eszközrendszere a
gyermekek testméreteihez, életkori sajátosságaihoz
és tudásszintjeihez igazodik, melyek hatékonyságát
az elmúlt évek nemzetközi vizsgálatai támasztják alá.
A kampány indulása óta a legnagyobb tenisznemzetek szabályrendszerei között eltérő iránymutatásokat találunk, amely ismereteket összehasonlítottuk
a hazai „Play and Stay” program működésével. Ezek
alapján elmondható, hogy a magyarországi versenyprogram hosszú távú fenntartásához stratégiai fejlesztésre van szükség, ezzel elérve, hogy a gyermekek
sportági pályafutásának ne a végső állomását, hanem
csupán a kezdetét jelentse a „Play and Stay”. A tanulmány célja, hogy felhívja a figyelmet a sportág hazai
utánpótlás rendszerében aktuálisan megjelenő problémáira, és nemzetközi példák bemutatása alapján
megoldási lehetőségeket javasoljon a sportág képviselőinek számára
Attempted Diels-Alder Reactions on Vindoline Derivatives
The Diels-Alder reaction of vindoline and methyl vinyl ketone resulted in a Friedel-Crafts reaction product. In the reaction between the ortho-quinone derivative of vindoline and N-phenylmaleimide, two anomalous products were obtained, a vindoline dimer, and a condensed vindoline derivative
Visible Light-Generated Antiviral Effect on Plasmonic Ag-TiO2-Based Reactive Nanocomposite Thin Film
Binding of Ca2+ Ions to Alkylbenzene Sulfonates: Micelle Formation, Second Critical Concentration and Precipitation
Anionic surfactants, such as sodium linear alkylbenzene sulfonates (NaLAS), are utilized in various fields, including industry, household, and agriculture. The efficiency of their use in aqueous environments is significantly affected by the presence of cations, Ca2+ and Mg2+ in particular, as they can decrease the concentration of the surfactant due to precipitation. To understand cation–sulfonate interactions better, we study both NaLAS colloidal solutions in the presence of CaCl2 and precipitates forming at higher salt concentrations. Upon addition of CaCl2, we find the surface tension and critical micelle concentration of NaLAS to decrease significantly, in line with earlier findings for alkylbenzylsulfonates in the presence of divalent cations. Strikingly, an increase in the surface tension is discernible above 0.6 g L–1 NaLAS, accompanied by the decrease of apparent micelle sizes, which in turn gives rise to transparent systems. Thus, there appears to be a second critical concentration indicating another micellar equilibrium. Furthermore, the maximum salt tolerance of the surfactant is 0.1 g L–1 Ca2+, above which rapid precipitation occurs yielding sparingly soluble CaLAS2∙2H2O
Visible Light-Generated Antiviral Effect on Plasmonic Ag-TiO2-Based Reactive Nanocomposite Thin Film
The recent coronavirus pandemic pointed out the vulnerability of humanity to new emerging infectious diseases. Experts warn that future pandemics may emerge more frequently with greater devastating effects on population health and the world economy. Although viruses are unable to propagate on lifeless surfaces, they can retain their infectivity and spread further on contact with these surfaces. The objective of our study is to analyze photoreactive composite films that exert antiviral effects upon illumination. Reactive plasmonic titanium dioxide-based polymeric nanocomposite film was prepared with a thickness of 1–1.5 µm, which produces reactive oxygen species (ROS) under visible light irradiation (λ ≥ 435 nm). These species are suitable for photooxidation of adsorbed organic molecules (e.g., benzoic acid) on the nanocomposite surface. Moreover, high molecular weight proteins are also degraded or partially oxidized in this process on the composite surface. Since the Ag0-TiO2/polymer composite film used showed excellent reactivity in the formation of OH• radicals, the photocatalytic effect on high molecular weight (M = ∼66.000 Da) bovine serum albumin (BSA) protein was investigated. Given that changes in the structure of the protein were observed upon exposure to light, we assumed virucidal effect of the illuminated photoreactive composite film. We tested this hypothesis using an airborne-transmitted herpesvirus. As a result, we obtained a drastic decrease in infection capability of the virus on the photoreactive surface compared to the control surface
A versenyzési kedv vizsgálata hazai utánpótlás teniszezőknél 2011-2020 között = Examination of the competitive mood in Hungarian youth tennis players between 2011 and 2020
Microcystin-LR, a Cyanobacterial Toxin, Induces Changes in the Organization of Membrane Compartments in Arabidopsis
To evaluate the effects of the cyanobacterial toxin microcystin-LR (MCY-LR, a protein phosphatase inhibitor) and diquat (DQ, an oxidative stress inducer) on the organization of tonoplast, the effect of MCY-LR on plastid stromule formation and on mitochondria was investigated in wild-type Arabidopsis. Tonoplast was also studied in PP2A catalytic (c3c4) and regulatory subunit mutants (fass-5 and fass-15). These novel studies were performed by CLSM microscopy. MCY-LR is produced during cyanobacterial blooms. The organization of tonoplast of PP2A mutants of Arabidopsis is much more sensitive to MCY-LR and DQ treatments than that of wild type. In c3c4, fass-5 and fass-15, control and treated plants showed increased vacuole fragmentation that was the strongest when the fass-5 mutant was treated with MCY-LR. It is assumed that both PP2A/C and B” subunits play an important role in normal formation and function of the tonoplast. In wild-type plants, MCY-LR affects mitochondria. Under the influence of MCY-LR, small, round-shaped mitochondria appeared, while long/fused mitochondria were typical in control plants. Presumably, MCY-LR either inhibits the fusion of mitochondria or induces fission. Consequently, PP2A also plays an important role in the fusion of mitochondria. MCY-LR also increased the frequency of stromules appearing on chloroplasts after 1 h treatments. Along the stromules, signals can be transported between plastids and endoplasmic reticulum. It is probable that they promote a faster response to stress