454 research outputs found

    Survey of Rehabilitation and Return-to-Work Practices Among U.S. Disability Carriers

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    [Excerpt] Disability insurance provides financial protection for workers who become disabled and are unable to perform their occupations. It is beneficial to both disabled employees and their employers to have their employees return to work as soon as they are able to do so. For disabled employees, benefits are typically 60% to 66 2/3% of their pre-disability income. For employers, an employee’s indefinite absence due to a disability involves the loss of productivity and the extra cost of training a new employee. In addition, the disabled employee often has on-the-job knowledge that may take a new employee many years to acquire. Many employees who receive disability benefits subsequently recover and return to work. Frequently, the cause of disablement is successfully treated with appropriate medical care, and the employees are able to return to their jobs with no additional assistance. However, for some claimants, the nature of their disability is severe enough to require extra support to facilitate their return

    Developing a growth-transition matrix for the stock assessment of the green sea urchin (Strongylocentrotus droebachiensis) off Maine

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    The green sea urchin (Strongylocentrotus droebachiensis) is important to the economy of Maine. It is the state’s fourth largest fishery by value. The fishery has experienced a continuous decline in landings since 1992 because of decreasing stock abundance. Because determining the age of sea urchins is often difficult, a formal stock assessment demands the development of a size-structured population dynamic model. One of the most important components in a size-structured model is a growth-transition matrix. We developed an approach for estimating the growth-transition matrix using von Bertalanffy growth parameters estimated in previous studies of the green sea urchin off Maine. This approach explicitly considers size-specific variations associated with yearly growth increments for these urchins. The proposed growth-transition matrix can be updated readily with new information on growth, which is important because changes in stock abundance and the ecosystem will likely result in changes in sea urchin key life history parameters including growth. This growth-transition matrix can be readily incorporated into the size-structured stock assessment model that has been developed for assessing the green sea urchin stock off Maine

    Investigating the role of Junctional Adhesion Molecule-C (JAM-C) in endothelial cell biology in vitro and in vivo using human and mouse models

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    PhDJunctional adhesion molecule C (JAM-C) is a component of endothelial cell (EC) tight junctions that has been implicated in a number of endothelial functions, such as angiogenesis and trafficking of leukocytes through the endothelium during inflammation. Work within our lab has identified that loss of JAM-C at EC junctions results in increased reverse transendothelial migration (rTEM) of neutrophils back into the circulation, a response that has been associated with the dissemination of inflammation to distant organs. Whilst the mechanism by which JAM-C is lost or redistributed away from EC junctions has begun to be elucidated, little is known about how loss of endothelial JAM-C impacts the functions of ECs. As such, this thesis aimed to investigate the effect of JAM-C deficiency on EC functions to unravel possible molecular and cellular mechanisms of mediating neutrophil rTEM. To address the effect of JAM-C deficiency on EC functions, an in vitro RNA interference (RNAi) approach was used to efficiently knock-down (KD) JAM-C in human umbilical vein ECs (HUVECs). Importantly, KD of JAM-C did not affect expression of other key EC junctional markers such as JAM-A and VE-Cadherin and cell proliferation and apoptosis were similarly unaffected. Gene expression profiling using microarrays revealed that JAM-C depleted HUVECs exhibited a pro-inflammatory phenotype under basal conditions that was characterised by increased expression of pro-inflammatory genes such as ICAM1 and IL8. Following IL-1β-induced inflammation, no difference in expression of pro-inflammatory genes was detected between control and JAM-C KD HUVECs. However, protein levels of secreted chemokines such as IL-8 were reduced in JAM-C KD HUVECs following stimulation with IL-1β. This was corroborated by in vivo studies demonstrating reduced levels of secreted chemokines in the plasma of mice where JAM-C was conditionally deleted from ECs. A novel finding of this work is the demonstration that JAM-C KD HUVECs exhibit increased autophagy under basal conditions. This might provide a potential mechanism for the reduced chemokine secretion that is observed in this system, whereby chemokines are preferentially trafficked for autophagosome-mediated degradation. Taken together, these findings indicate a multi-functional role for JAM-C in regulating EC homeostasis under basal conditions. JAM-C KD ECs respond aberrantly to inflammatory stimuli by secreting reduced chemokine levels, a consequence that could provide novel insights into the mechanisms of neutrophil rTEM under conditions of endothelial JAM-C loss.Wellcome Trus

    Paradoxical facilitation alongside interhemispheric inhibition

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    Neurophysiological experiments using transcranial magnetic stimulation (TMS) have sought to probe the function of the motor division of the corpus callosum. Primary motor cortex sends projections via the corpus callosum with a net inhibitory influence on the homologous region of the opposite hemisphere. Interhemispheric inhibition (IHI) experiments probe this inhibitory pathway. A test stimulus (TS) delivered to the motor cortex in one hemisphere elicits motor evoked potentials (MEPs) in a target muscle, while a conditioning stimulus (CS) applied to the homologous region of the opposite hemisphere modulates the effect of the TS. We predicted that large CS MEPs would be associated with increased IHI since they should be a reliable index of how effectively contralateral motor cortex was stimulated and therefore of the magnitude of interhemispheric inhibition. However, we observed a strong tendency for larger CS MEPs to be associated with reduced interhemispheric inhibition which in the extreme lead to a net effect of facilitation. This surprising effect was large, systematic, and observed in nearly all participants. We outline several hypotheses for mechanisms which may underlie this phenomenon to guide future research. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00221-021-06183-9

    Executable Architectures and their Application to a Geographically Distributed Air Operations Center

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    Integrated Architectures and Network Centric Warfare represent two central concepts in the Department of Defense\u27s (DoD) on-going transformation. The true power of integrated architectures is brought to bear when they are combined with simulation to move beyond a static representation and create an executable architecture. This architecture can then be used to experiment with system configurations and parameter values to guide employment decisions. The process of developing and utilizing an executable architecture will be employed to assess an Air Operations Center (AOC). This thesis applies and expands upon the methodology of Dr. Alexander Levis, former Chief Scientist of the Air Force, to the static architecture representing the Aerospace Operations Center (AOC). Using Colored Petri Nets and other simulation tools, an executable architecture for the AOC\u27s Air Tasking Order (ATO) production thread was developed. These models were then used to compare the performance of a current, forward-deployed AOC configuration to three other potential configurations that utilize a network centric environment to deploy a portion of the AOC and provide reach-back capabilities to the non-deployed units. Performance was measured by the amount of time required to execute the ATO cycle under each configuration. Communication requirements were analyzed for each configuration and stochastic delays were modeled for all transactions in which requirements could not be met due to the physical configuration of the AOC elements. All four configurations were found to exhibit statistically different behavior with regard to ATO cycle time

    Magnetic resonance spectroscopic imaging in gliomas: clinical diagnosis and radiotherapy planning

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    The reprogramming of cellular metabolism is a hallmark of cancer diagnosis and prognosis. Proton magnetic resonance spectroscopic imaging (MRSI) is a non-invasive diagnostic technique for investigating brain metabolism to establish cancer diagnosis and IDH gene mutation diagnosis as well as facilitate pre-operative planning and treatment response monitoring. By allowing tissue metabolism to be quantified, MRSI provides added value to conventional MRI. MRSI can generate metabolite maps from a single volume or multiple volume elements within the whole brain. Metabolites such as NAA, Cho and Cr, as well as their ratios Cho:NAA ratio and Cho:Cr ratio, have been used to provide tumor diagnosis and aid in radiation therapy planning as well as treatment assessment. In addition to these common metabolites, 2-hydroxygluterate (2HG) has also been quantified using MRSI following the recent discovery of IDH mutations in gliomas. This has opened up targeted drug development to inhibit the mutant IDH pathway. This review provides guidance on MRSI in brain gliomas, including its acquisition, analysis methods, and evolving clinical applications

    ARHGEF18/p114RhoGEF coordinates PKA/CREB signalling and actomyosin remodelling to promote trophoblast cell-cell fusion during placenta morphogenesis

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    Coordination of cell-cell adhesion, actomyosin dynamics and gene expression is crucial for morphogenetic processes underlying tissue and organ development. Rho GTPases are main regulators of the cytoskeleton and adhesion. They are activated by guanine nucleotide exchange factors in a spatially and temporally controlled manner. However, the roles of these Rho GTPase activators during complex developmental processes are still poorly understood. ARHGEF18/p114RhoGEF is a tight junction-associated RhoA activator that forms complexes with myosin II, and regulates actomyosin contractility. Here we show that p114RhoGEF/ARHGEF18 is required for mouse syncytiotrophoblast differentiation and placenta development. In vitro and in vivo experiments identify that p114RhoGEF controls expression of AKAP12, a protein regulating protein kinase A (PKA) signaling, and is required for PKA-induced actomyosin remodeling, cAMPresponsive element binding protein (CREB)-driven gene expression of proteins required for trophoblast differentiation, and, hence, trophoblast cell-cell fusion. Our data thus indicate that p114RhoGEF links actomyosin dynamics and cell-cell junctions to PKA/CREB signaling, gene expression and cell-cell fusion
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