910 research outputs found
A COMPLETE KINEMATIC, KINETIC, AND ELECTROMYOGRAPHICAL ANALYSIS OF THE FOOTBALL THROW IN COLLEGIATE QUARTERBACKS
The biomechanics of the overhead throw has been extensively studied in regards to baseball pitching. However, an understanding of the proper mechanics needed to successfully throw a football has not previously been investigated. Thus, the purpose of this study was to investigate the kinematics, kinetics, and electromyography of the football throws in elite quarterbacks. Three collegiate quarterbacks were evaluated using a multi-camera motion capture system and electromyography electrodes. The results of this study are able to give a breakdown in the types of mechanics needed in each of the phases of the throw. This study demonstrated that during the early cocking phase, most of the movement seen in the upper body occurs in the frontal plane to abduct the shoulder. During the late cocking phase, the shoulder holds a constant abduction angle and begins to externally rotate. The shoulder reaches a value of 117° of external rotation, much less than has previously been reported. During the acceleration phase, the shoulder rapidly internally rotates as well as horizontally adducts. Once the ball is released, the shoulder has to produce large forces and muscle activity to slow down the rotation. These results will be able to give coaches and players a tool for what to look for when evaluating the mechanics of an individual
Unfolded protein response pathways in skeletal muscle homeostasis.
Skeletal muscle mass, contractile properties, and metabolic function are regulated through the coordinated activation of multiple intracellular signaling pathways and genetic reprogramming. The endoplasmic reticulum (ER) plays a pivotal role in protein folding and calcium homeostasis in many cell types, including skeletal muscle. Disruption of calcium levels or accumulation of misfolded proteins in the ER lumen leads to stress, which results in the activation of a signaling network called the unfolded protein response (UPR). Further, recent studies have suggested that in certain conditions, UPR pathways can be activated independent of ER stress. However, the role of ER stress and the UPR in the regulation of skeletal muscle mass and function had not been previously investigated. This dissertation demonstrates that the markers of ER stress are increased in skeletal muscle of mouse models of cancer cachexia. Chronic administration of 4-phenylbutyrate (4-PBA), a molecular chaperon and an inhibitor of ER stress, leads to the loss of skeletal muscle mass and function in naïve conditions and in Lewis lung carcinoma (LLC) tumor-bearing mice. 4-PBA also causes atrophy in cultured primary myotubes. Further, our results demonstrate that the targeted deletion of X-box binding protein (XBP1), a downstream target of the inositol-requiring enzyme 1α (IRE1α) arm of the UPR, attenuates the loss of skeletal muscle mass in LLC tumor-bearing mice. Overexpression of a spliced form of XBP1 causes atrophy and induces the gene expression of several proinflammatory cytokines and the components of ubiquitin proteasome system and autophagy in cultured myotubes. Our results also demonstrate that toll-like receptors-mediated signaling is responsible, at least in part, for the activation of the UPR in skeletal muscle of LLC tumor-bearing mice. Finally, the role of the XBP1 in skeletal muscle growth and regeneration was also investigated. Results showed XBP1 mediates overload-induced myofiber hypertrophy and skeletal muscle regeneration potentially through augmenting the proliferation of satellite cells in a non-cell-autonomous manner. Altogether, this dissertation provides initial evidence that while basal levels of ER stress/UPR is essential for the maintenance of skeletal muscle mass and strength, supra-physiological activation of the UPR, especially the IRE1/XBP1 arm, causes skeletal muscle wasting
Impact of foot progression angle modification on plantar loading in individuals with diabetes mellitus and peripheral neuropathy
AIMS: To determine if participants can reduce foot progression angle (FPA), and if FPA reduction decreases regional plantar stresses and forces in individuals with diabetes. METHODS: DESIGN: Three-group cross-sectional design with repeated measures. SUBJECTS: twenty-eight participants either with diabetes mellitus (DM), diabetes and peripheral neuropathy with (DMPN+NPU) or without a prior history of ulceration (DMPNâNPU) were studied. INTERVENTION: Participants were first instructed to walk over a 3.6 m walkway at their preferred FPA, and then to walk with their foot aligned parallel with the line of gait progression at their self-selected speed. Dynamic plantar kinetics in six masked regions were collected using an EMED-st-P-2 pedobarograph. MAIN MEASURES: Primary outcome measures were FPA, peak plantar pressure (PPP), and force-time integral (FTI). A repeated measures ANOVA was conducted to determine group differences in FPA for both walking conditions. Regional differences in PPPs and FTIs between preferred and corrected walking conditions were analyzed using repeated measures ANCOVA. RESULTS: Participants showed a reduction in FPA magnitude on the âInvolvedâ foot between the preferred and corrected walking conditions (p<0.01). There were no differences in PPPs or FTIs in any mask between walking conditions (p>0.05). CONCLUSION: Results from this investigation offer important evidence that people with diabetes can modify their FPA with a simple intervention of visual and verbal cueing. Future research should examine if gait retraining strategies in regular footwear more effectively offload areas of elevated regional plantar stresses and forces in adults with diabetes mellitus and peripheral neuropathy
Attitude Determination from Single-Antenna Carrier-Phase Measurements
A model of carrier phase measurement (as carried out by a satellite
navigation receiver) is formulated based on electromagnetic theory. The model
shows that the phase of the open-circuit voltage induced in the receiver
antenna with respect to a local oscillator (in the receiver) depends on the
relative orientation of the receiving and transmitting antennas. The model
shows that using a {\it single} receiving antenna, and making carrier phase
measurements to seven satellites, the 3-axis attitude of a user platform (in
addition to its position and time) can be computed relative to an initial
point. This measurement model can also be used to create high-fidelity
satellite signal simulators that take into account the effect of platform
rotation as well as translation.Comment: 12 pages, and one figure. Published in J. Appl. Phys. vol. 91, No. 7,
April 1, 200
Formin-based control of the actin cytoskeleton during cytokinesis
Cytokinesis, the terminal event in the canonical cell cycle, physically separates daughter cells following mitosis. For cleavage to occur in many eukaryotes, a cytokinetic ring must assemble and constrict between divided genomes. Although dozens of different molecules localize to and participate within the cytokinetic ring, the core machinery comprises linear actin filaments. Accordingly, formins, which nucleate and elongate F-actin (filamentous actin) for the cytokinetic ring, are required for cytokinesis in diverse species. In the present article, we discuss specific modes of formin-based actin regulation during cell division and highlight emerging mechanisms and questions on this topic. © 2013 Biochemical Society
Substance use disorders and the risk of suicide mortality among men and women in the US Veterans Health Administration
Background and AimsLimited information is available regarding links between specific substance use disorders (SUDs) and suicide mortality; however, the preliminary evidence that is available suggests that suicide risk associated with SUDs may differ for men and women. This study aimed to estimate associations between SUDs and suicide for men and women receiving Veterans Health Administration (VHA) care.DesignA cohort study using national administrative health records.SettingNational VHA system, USA.ParticipantsAll VHA users in fiscal year (FY) 2005 who were alive at the beginning of FY 2006 (n = 4â863â086).MeasurementsThe primary outcome of suicide mortality was assessed via FY 2006â2011 National Death Index (NDI) records. Current SUD diagnoses were the primary predictors of interest, and were assessed via FY 2004â2005 VHA National Patient Care Database (NPCD) records.FindingsIn unadjusted analyses, a diagnosis of any current SUD and the specific current diagnoses of alcohol, cocaine, cannabis, opioid, amphetamine and sedative use disorders were all associated significantly with increased risk of suicide for both males and females [hazard ratios (HRs)] ranging from 1.35 for cocaine use disorder to 4.74 for sedative use disorder for men, and 3.89 for cannabis use disorder to 11.36 for sedative use disorder for women]. Further, the HR estimates for the relations between any SUD, alcohol, cocaine and opioid use disorders and suicide were significantly stronger for women than men (P < 0.05). After adjustment for other factors, most notably comorbid psychiatric diagnoses, associations linking SUDs with suicide were attenuated markedly and the greater suicide risk among females was observed for only any SUD and opioid use disorder (P < 0.05).ConclusionsCurrent substance use disorders (SUDs) signal increased suicide risk, especially among women, and may be important markers to consider including in suicide risk assessment strategies. None the less, other coâoccurring psychiatric disorders may partially explain associations between SUDs and suicide, as well as the observed excess suicide risk associated with SUDs among women.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137620/1/add13774.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137620/2/add13774_am.pd
Introducing mobile edge computing capabilities through distributed 5G Cloud Enabled Small Cells
Current trends in broadband mobile networks are addressed towards the placement of different capabilities at the edge of the mobile network in a centralised way. On one hand, the split of the eNB between baseband processing units and remote radio headers makes it possible to process some of the protocols in centralised premises, likely with virtualised resources. On the other hand, mobile edge computing makes use of processing and storage capabilities close to the air interface in order to deploy optimised services with minimum delay. The confluence of both trends is a hot topic in the definition of future 5G networks. The full centralisation of both technologies in cloud data centres imposes stringent requirements to the fronthaul connections in terms of throughput and latency. Therefore, all those cells with limited network access would not be able to offer these types of services. This paper proposes a solution for these cases, based on the placement of processing and storage capabilities close to the remote units, which is especially well suited for the deployment of clusters of small cells. The proposed cloud-enabled small cells include a highly efficient microserver with a limited set of virtualised resources offered to the cluster of small cells. As a result, a light data centre is created and commonly used for deploying centralised eNB and mobile edge computing functionalities. The paper covers the proposed architecture, with special focus on the integration of both aspects, and possible scenarios of application.Peer ReviewedPostprint (author's final draft
A novel germline mutation of PDGFR-ÎČ might be associated with clinical response of colorectal cancer to regorafenib
This is the first description of a germline mutation of the PDGFR-ÎČ gene, that correlates with response to regorafenib in a patient with metastatic colorectal cance
SIN-dependent phosphoinhibition of formin multimerization controls fission yeast cytokinesis
Many eukaryotes accomplish cell division by building and constricting a medial actomyosin-based cytokinetic ring (CR). In Schizosaccharomyces pombe, a Hippo-related signaling pathway termed the septation initiation network (SIN) controls CR formation, maintenance, and constriction. However, how the SIN regulates integral CR components was unknown. Here, we identify the essential cytokinetic formin Cdc12 as a key CR substrate of SIN kinase Sid2. Eliminating Sid2-mediated Cdc12 phosphorylation leads to persistent Cdc12 clustering, which prevents CR assembly in the absence of anillin-like Mid1 and causes CRs to collapse when cytokinesis is delayed. Molecularly, Sid2 phosphorylation of Cdc12 abrogates multimerization of a previously unrecognized Cdc12 domain that confers F-actin bundling activity. Taken together, our findings identify a SIN-triggered oligomeric switch that modulates cytokinetic formin function, revealing a novel mechanism of actin cytoskeleton regulation during cell division. © 2013 Bohnert et al
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