84 research outputs found

    LANDING DEVELOPMENT: A FIRST LOOK AT YOUNG CHILDREN

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    The purpose of this study was to examine sagittal and frontal views of children (n=14) aged 4-9 landing from a maximal effort vertical jump to begin a description of landing development. Video records (collected at 30 frames/sec) of the jump and landing were viewed frame by frame with Windows Movie Maker and analyzed with a simple scoring system validated to detect improper movements during landing. Findings indicated that this stop-landing task challenged balance as most landings included a step, straddled foot position, and a wide stance. Mechanisms for force absorption (knee and hip flexion) tended to occur more often in landings of older children, but incidences of knee valgus also increased with age. Further investigation may establish developmental expectations for landing and help coaches and physical educators correct potentially harmful patterns as children age and pursue more competitive sport

    Immundefekte bei chronischer Rhinosinusitis : eine bedeutende und oft unterschätzte Ursache

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    Background Chronic rhinosinusitis (CRS) is one of the most frequent chronic diseases. Among these patients the prevalence of immune defects is higher than in the healthy general population. Methods A selective review of the literature was carried out in PubMed and Medline covering the period between 2008 and 2019. Additionally, recent German publications in journals not listed in the abovementioned databases were analyzed. Results The diagnostic workflow with respect to the immunodeficiency consists of a detailed anamnesis and physical examination, laboratory tests and the antibody reaction to polysaccharide vaccines and antigens. Beside antibiotic treatment, vaccinations and immunoglobulin replacement are available. Notwithstanding the above, functional endoscopic surgery of the paranasal sinuses should be performed according to guideline recommendations. Conclusion Patients with CRS who do not sufficiently respond to conservative and surgical treatment should be checked for underlying immunodeficiencies

    Photocleavable core cross-linked polymeric micelles of polypept(o)ides and ruthenium(II) complexes

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    Core cross-linking of polymeric micelles has been demonstrated to contribute to enhanced stability that can improve the therapeutic efficacy. Photochemistry has the potential to provide spatial resolution and on-demand drug release. In this study, light-sensitive polypyridyl-ruthenium(II) complexes were combined with polypept(o)ides for photocleavable core cross-linked polymeric micelles. Block copolymers of polysarcosine-block-poly(glutamic acid) were synthesized by ring-opening N-carboxyanhydride polymerization and modified with aromatic nitrile-groups on the glutamic acid side chain. The modified copolymers self-assembled into micelles and were cross-linked by cis-diaquabis(2,2'-bipyridine)-ruthenium(II) ([Ru(bpy)2(H2O)2]2+) or cis-diaquabis(2,2'-biquinoline)-ruthenium(II) ([Ru(biq)2(H2O)2]2+). Depending on the flexibility and hydrophobicity of the nitrile linker, either small spherical structures (Dh 45 nm, PDI 0.11) or worm-like micelles were obtained. The cross-linking reaction did not affect the overall size distribution but induced a change in the metal-to-ligand charge transfer peak from 482 to 420 nm and 592 to 548 nm. The cross-linked micelles displayed colloidal stability after incubation with human blood plasma and during gel permeation chromatography in hexafluoroisopropanol. Light-induced cleavage of [Ru(bpy)2(H2O)2]2+ was accomplished within 300 s, while [Ru(biq)2(H2O)2]2+ could not be completely released. Analysis in HuH-7 cells revealed increased cytotoxicity via micellar delivery of [Ru(bpy)2(H2O)2]2+ but mostly irradiation damage for [Ru(biq)2(H2O)2]2+. Further evaluation in ovo confirmed stable circulation pointing towards the future development of quick-release complexes.Drug Delivery Technolog

    Dominant Glint Based Prey Localization in Horseshoe Bats: A Possible Strategy for Noise Rejection

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    Rhinolophidae or Horseshoe bats emit long and narrowband calls. Fluttering insect prey generates echoes in which amplitude and frequency shifts are present, i.e. glints. These glints are reliable cues about the presence of prey and also encode certain properties of the prey. In this paper, we propose that these glints, i.e. the dominant glints, are also reliable signals upon which to base prey localization. In contrast to the spectral cues used by many other bats, the localization cues in Rhinolophidae are most likely provided by self-induced amplitude modulations generated by pinnae movement. Amplitude variations in the echo not introduced by the moving pinnae can be considered as noise interfering with the localization process. The amplitude of the dominant glints is very stable. Therefore, these parts of the echoes contain very little noise. However, using only the dominant glints potentially comes at a cost. Depending on the flutter rate of the insect, a limited number of dominant glints will be present in each echo giving the bat a limited number of sample points on which to base localization. We evaluate the feasibility of a strategy under which Rhinolophidae use only dominant glints. We use a computational model of the echolocation task faced by Rhinolophidae. Our model includes the spatial filtering of the echoes by the morphology of the sonar apparatus of Rhinolophus rouxii as well as the amplitude modulations introduced by pinnae movements. Using this model, we evaluate whether the dominant glints provide Rhinolophidae with enough information to perform localization. Our simulations show that Rhinolophidae can use dominant glints in the echoes as carriers for self-induced amplitude modulations serving as localization cues. In particular, it is shown that the reduction in noise achieved by using only the dominant glints outweighs the information loss that occurs by sampling the echo

    Lenkstellsysteme

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