1,115 research outputs found

    Ball Pressure Correlations with Peak Impact Force and the Potential for Cumulative mTBI when Heading a Soccer Ball

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    Soccer is a unique sport in which athletes use their heads as tools for gameplay, which may ultimately cause cumulative traumatic brain injuries. Due to rising popularity of soccer in the United States alongside the increased occurrence of CTE and mTBI in other contact sports, there is a growing concern over how to keep the repetitive forces caused by heading, as low as possible. Different variables that can affect the peak force felt when heading a soccer ball can be simulated and compared with in-game data, however, this has never been properly tested before. In the present study two size five and two size four balls were tested at three different gage pressures (8.5, 12 and 16.2 psi). These were kicked at different velocities towards a force plate, in order to simulate an in game kick, to collect data about the peak force and impulse exerted on a head. Data recollected allowed us to find an exisiting linaer relationship between velocity and the force exerted on the force platform. In addition, increasing the ball pressure, lead to higher forces, as observed through the difference of kicking a soccer ball inflated at 16.2 psi rather than 8.5 psi. The higher mass and diameter seen within distinct ball sizes affects the impact force, due to the related trajectory and drag force changes. The results found allow us to correlate with previous studies and confirm that by repeatedly heading a soccer ball you are prone to cumulative brain injuries. Additionally, stricter policies should be enforced, such as not allowing ball pressure to exceed 8.5 psi, thus keeping the game safer for all athletes involved

    Geomorphology of the southernmost Longitudinal Valley fault: Implications for evolution of the active suture of eastern Taiwan

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    In order to understand fully the deformational patterns of the Longitudinal Valley fault system, a major structure along the eastern suture of Taiwan, we mapped geomorphic features near the southern end of the Longitudinal Valley, where many well‐developed fluvial landforms record deformation along multiple strands of the fault. Our analysis shows that the Longitudinal Valley fault there comprises two major strands. The Luyeh strand, on the west, has predominantly reverse motion. The Peinan strand, on the east, has a significant left‐lateral component. Between the two strands, late Quaternary fluvial sediments and surfaces exhibit progressive deformation. The Luyeh strand dies out to the north, where it steps to the east and joins the Peinan strand to become the main strand of the reverse sinistral Longitudinal Valley fault. To the south, the Luyeh strand becomes an E‐W striking monocline. This suggests that the reverse motion on the Longitudinal Valley system decreases drastically at that point. The Longitudinal Valley fault system is therefore likely to terminate abruptly there and does not seem to connect to any existing structure further to the south. This abrupt structural change suggests that the development of the Longitudinal Valley suture occurs through discrete structural “jumps,” rather than by a continuous northward maturation

    High-resolution upper Pliocene to Pleistocene calcareous nannofossil biostratigraphy in Ocean Drilling Program Hole 1146A in the South China Sea

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    We established a high-resolution calcareous nannofossil biostratigraphy for the late Pliocene–Pleistocene by analyzing a 242 m-thick, continuous sedimentary succession from Ocean Drilling Program Site 1146, Hole A, in the South China Sea (SCS). A total of 14 calcareous nannofossil datums were detected in the SCS succession. They are, in descending order: first occurrence (FO) of Emiliania huxleyi, last occurrence (LO) of Pseudoemiliania lacunosa, LO of Reticulofenestra asanoi, FO of Gephyrocapsa parallela, FO of R. asanoi, LO of large Gephyrocapsa spp., FO of large G. spp., FO of Gephyrocapsa oceanica, FO of Gephyrocapsa caribbeanica, LO of Calcidiscus macintyrei, LO of Discoaster brouweri, LO of Discoaster pentaradiatus, LO of Discoaster surculus, and LO of Discoaster tamalis. The FO of E. huxleyi was not precisely detected due to poor preservation and dissolution of nannofossils in the underlying strata. We refined the previous calcareous nannofossil biostratigraphy in the SCS by identifying Gephyrocapsa species and four evolutionary extinction events of the genus Discoaster. The proposed calcareous nannofossil biostratigraphy correlates with those reported in other terrestrial and marine areas/sites and global benthic foraminiferal δ18O records. The age–depth curves based on nannofossil biostratigraphy indicate a significant increase in the sedimentation rates at the LO of R. asanoi (0.91–0.85 Ma). The timing of this increase corresponds to reef expansion in the Ryukyu Islands linked to a stepwise increase in Kuroshio Current intensity. This timing is broadly coeval with a sea surface temperature increase of ∼2°C in the northwestern Pacific due to expansion of the Western Pacific Warm Pool towards the north and south subtropical regions. This can be explained by increased weathering and erosion of terrestrial areas in glacial periods and increased rainfall causing higher sediment transport in interglacial periods, which were both linked to Middle Pleistocene Transition-related climatic changes

    Development of Standard Criteria to Evaluate the Effectiveness of Helmets at Decreasing the Risk of Concussions

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    In many sports, such as American football, accumulations of mild traumatic brain injuries have been suggested as a possible link to neurodegeneration and future mental disorders. With head impacts occurring at all levels of competition and in different sports, it is critical to develop an accurate method for quantifying the effects of head impacts and determining the efficacy of helmets. This study examines the derivation of different dimensionless numbers and ascertains the critical factors needed to predict the effects of head impacts, specifically the resulting accelerations from an impact. Given a known force of impact, parameters such as peak translation acceleration and impact duration were collected for a total of 200 impacts at 10 locations around the head. These parameters were used in conjunction with dimensionless numbers to compare various helmet designs across sports. Five input and four output criteria, or π variables, were derived using fundamental variables of total mass, width of neck, and the difference between muscle reaction time and the impact duration. By determining the coefficients of the governing equations for each output π variable, the impulse of impacts had a consistent effect on helmet efficacy, while the masses and radii of helmets contained confounding variables that made it difficult to predict the effectiveness of attenuating the head accelerations

    Nonstructural proteins nsp2TF and nsp2N of porcine reproductive and respiratory syndrome virus (PRRSV) play important roles in suppressing host innate immune responses.

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    Recently, we identified a unique -2/-1 ribosomal frameshift mechanism in PRRSV, which yields two truncated forms of nonstructural protein (nsp) 2 variants, nsp2TF and nsp2N. Here, in vitro expression of individual PRRSV nsp2TF and nsp2N demonstrated their ability to suppress cellular innate immune responses in transfected cells. Two recombinant viruses were further analyzed, in which either nsp2TF was C-terminally truncated (vKO1) or expression of both nsp2TF and nsp2N was knocked out (vKO2). Host cellular mRNA profiling showed that a panel of cellular immune genes, in particular those involved in innate immunity, was upregulated in cells infected with vKO1 and vKO2. Compared to the wild-type virus, vKO1 and vKO2 expedited the IFN-α response and increased NK cell cytotoxicity, and subsequently enhanced T cell immune responses in infected pigs. Our data strongly implicate nsp2TF/nsp2N in arteriviral immune evasion and demonstrate that nsp2TF/nsp2N-deficient PRRSV is less capable of counteracting host innate immune responses
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