217 research outputs found

    Delayed hearing loss following vestibular schwannoma surgery: Behavioural and electrophysiological responses in the early postoperative period

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    Some patients suffer hearing loss in the early postoperative period following vestibular schwannoma (VS) excision despite having intact hearing immediately after surgery. As this phenomenon has rarely been documented or described, the putative mechanism remains vague. The objective of the current study was to document the patterns of change in behavioural and electrophysiological responses in patients following VS surgery to better describe the phenomenon of delayed hearing loss. In particular, we aimed to determine whether the impairment that eventually leads to delayed hearing loss is neural or cochlear in origin. Auditory function was monitored in six adult patients who underwent surgery at Christchurch Public Hospital for excision of unilateral vestibular schwannoma through the retrosigmoid approach. Patients were assessed pre- and postoperatively by puretone audiometry, speech audiometry, tympanometry, distortion product otoacoustic emissions (DPOAEs), and auditory brainstem response (ABR). When measurable hearing was demonstrated postoperatively, pure-tone audiometry, speech audiometry and ABR were assessed at 24 hour intervals following surgery. Transtympanic electrocochleography (ECochG) was carried out if wave I of the ABR was lost during the postoperative period. Postoperative monitoring revealed that 4 patients suffered permanent anacusis and the remaining 2 patients had permanent hearing preservation. There were no patients who experienced delayed hearing loss in the early postoperative period. A phenomenon similar to delayed hearing loss was observed in case 2 who demonstrated loss of ABR wave I on the 7th postoperative day. Postoperative ECochG recorded in this case showed an enhanced negative SP on the operated side. The findings of this study are discussed in detail with particular reference to the underlying pathophysiology

    Surface Tethered Epidermal Growth Factor Protects Proliferating and Differentiating Multipotential Stromal Cells from FasL-Induced Apoptosis

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    Multipotential stromal cells or mesenchymal stem cells (MSCs) have been proposed as aids in regenerating bone and adipose tissues, as these cells form osteoblasts and adipocytes. A major obstacle to this use of MSC is the initial loss of cells postimplantation. This cell death in part is due to ubiquitous nonspecific inflammatory cytokines such as FasL generated in the implant site. Our group previously found that soluble epidermal growth factor (sEGF) promotes MSC expansion. Furthermore, tethering EGF (tEGF) onto a two-dimensional surface altered MSC responses, by restricting epidermal growth factor receptor (EGFR) to the cell surface, causing sustained activation of EGFR, and promoting survival from FasL-induced death. sEGF by causing internalization of EGFR does not support MSC survival. However, for tEGF to be useful in bone regeneration, it needs to allow for MSC differentiation into osteoblasts while also protecting emerging osteoblasts from apoptosis. tEGF did not block induced differentiation of MSCs into osteoblasts, or adipocytes, a common default MSC-differentiation pathway. MSC-derived preosteoblasts showed increased Fas levels and became more susceptible to FasL-induced death, which tEGF prevented. Differentiating adipocytes underwent a reduction in Fas expression and became resistant to FasL-induced death, with tEGF having no further survival effect. tEGF protected undifferentiated MSC from combined insults of FasL, serum deprivation, and physiologic hypoxia. Additionally, tEGF was dominant in the face of sEGF to protect MSC from FasL-induced death. Our results suggest that MSCs and differentiating osteoblasts need protective signals to survive in the inflammatory wound milieu and that tEGF can serve this function.National Institute of General Medical Sciences (U.S.) (GM069668)National Institute of Dental and Craniofacial Research (U.S.) (DE019523

    Evaluation of Small Form Factor Fiber Optic Interconnects for the NASA Electronics Parts and Packaging Program (NEPP)

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    The Diamond AVIM optical fiber connector has been used for over a decade in flight environments. AVIM which stands for Aviation Intermediate Maintenance is always referenced as a fiber optic connector type from the DIN (Deutsches Institut fur Normung) family of optical fiber connectors. The newly available Mini AVIM and DMI (Definition Multimedia Interface) connectors also by Diamond provide similar features as the high performance AVIM with the added benefits of being small form factor for board mount and internal box use where long connectors and strain relief can not be accommodated. Transceiver, fiber laser technology and receiver optic technology based on small sized constraints will benefit the most by the reduction in connector form factor. It is for this reason that the Mini AVIM is being evaluated for multimode and single mode optical fiber use in both fiber based and cable based packaging configurations. In a fiber based termination, there are no cable materials to bond to the connector. The only bonding that is conducted is the mounting of the fiber with epoxy to the connector ferrules (which are called DMI ferrules). In a cable configuration, the compatibility of the connector subcomponents along with the upjacketing materials of the cable around the fiber needs to be considered carefully for termination fabrication. Cabled terminations will show greater insertion loss and high probability of failures during thermal cycling testing. This is due to the stressing of the combination of materials that each have different Coefficients of Thermal Expansion (CTE's) and that are bonded together to the connector subcomponents. As the materials flex during thermal excursions, forces are applied to the termination and can make the system fail if the grouping of materials (per their CTE's) are not compatible and this includes cable materials, epoxies, ferrule and connector body components. For this evaluation, multimode 100 micron core step index fiber was used for the fiber terminated condition, and single mode SMF-28 upjacketed with W.L. Gore Flexlite was used for the cabled configuration. For background purposes, a comparison is presented here for information purposes between the high performance AVIM connector features and the Mini AVIM small form factor connectors. Basic connector features are described here

    IMPACT: The Journal of the Center for Interdisciplinary Teaching and Learning. Volume 8, Issue 2, Summer 2019

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    Many of us look for ways to help students forge concrete connections between their academic studies and the real world. Universities encourage professors to develop community-based learning, allowing students to contribute to the community beyond their campus in a way that enhances their academic studies and enables them to create these connections. Scholars have theorized the many benefits of community-based learning, but professors have many questions about how to implement community-based learning in practice. What does a successful community-based learning assignment look like? What are the different ways to assess students’ learning experiences in community-based learning assignments? How can one build effective partnerships with community organizations? In these pages, you will find practical advice, theoretical framework, and firsthand accounts of community-engaged teaching across disciplines. Learn from professors who have designed assignments allowing students to complete community projects with refugees, prisoners, veterans, elementary school children, science museums, nursing homes, public libraries, and ESL populations. Students in an Anthropology course, for instance, conduct oral history interviews with refugees, and provide written transcriptions of the interviews that the refugees can then use as a learning tool in ESL classes. In a Science Methods class, students collaborate with an aquarium to produce meaningful exhibits that educate the public. First-year writing students work with veterans to create autobiographical films and write papers related to the project

    The Fiber Optic System for the Advanced Topographic Laser Altimeter System (ATLAS) Instrument

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    The Advanced Topographic Laser Altimeter System (ATLAS) Instrument has been in integration and testing over the past 18 months in preparation for the Ice, Cloud and Land Elevation Satellite - 2 (ICESat-2) Mission, scheduled to launch in 2017. ICESat-2 is the follow on to ICESat which launched in 2003 and operated until 2009. ATLAS will measure the elevation of ice sheets, glaciers and sea ice or the "cryosphere" (as well as terrain) to provide data for assessing the earth's global climate changes. Where ICESat's instrument, the Geo-Science Laser Altimeter (GLAS) used a single beam measured with a 70 m spot on the ground and a distance between spots of 170 m, ATLAS will measure a spot size of 10 m with a spacing of 70 cm using six beams to measure terrain height changes as small as 4 mm. The ATLAS pulsed transmission system consists of two lasers operating at 532 nm with transmitter optics for beam steering, a diffractive optical element that splits the signal into 6 separate beams, receivers for start pulse detection and a wavelength tracking system. The optical receiver telescope system consists of optics that focus all six beams into optical fibers that feed a filter system that transmits the signal via fiber assemblies to the detectors. Also included on the instrument is a system that calibrates the alignment of the transmitted pulses to the receiver optics for precise signal capture. The larger electro optical subsystems for transmission, calibration, and signal receive, stay aligned and transmitting sufficiently due to the optical fiber system that links them together. The robust design of the fiber optic system, consisting of a variety of multi fiber arrays and simplex assemblies with multiple fiber core sizes and types, will enable the system to maintain consistent critical alignments for the entire life of the mission. Some of the development approaches used to meet the challenging optical system requirements for ATLAS are discussed here

    Efectividad de la terapia cognitiva basada en el mindfulness (MBCT) en el tratamiento de la depresión en adultos: revisión aplicada

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    La depresión es uno de los trastornos mentales más comunes afectando al 5% de la población adulta en el mundo. Por otro lado, la terapia cognitiva basada en mindfulness (MBCT) se muestra como una herramienta efectiva en el aumento de la flexibilidad cognitiva, mejoramiento de los déficits cognitivos, en la prevención de recaída y disminución de los síntomas depresivos, en personas con depresión crónica, recurrente o con resistencia al tratamiento. Por ese motivo, el objetivo principal de este reporte es investigar la efectividad de la MBCT en la disminución de los síntomas depresivos en adultos. Se realizó una búsqueda en las bases de datos de Web of Science, EBSCOhost, SCOPUS y Proquest, siguiendo los criterios PRISMA, donde se seleccionaron 10 artículos que investigaron la efectividad de la MBCT sobre la depresión; ya sea como terapia exclusiva o complementaria a otros tratamientos. En los resultados, se encontró que la MBCT tiene efectividad en la disminución de los síntomas depresivos; en personas con depresión mayor/crónica, recurrente, o resistentes al tratamiento. Como resultados secundarios, se encontró que la MBCT contribuye en mejores niveles de factores protectores como autocompasión y habilidades de mindfulness.Depression is one of the most common mental disorders affecting 5% of the adult population in the world. On the other hand, mindfulness-based cognitive therapy (MBCT) is shown to be an effective tool in increasing cognitive flexibility, improving cognitive deficits, in the prevention of relapse and reduction of depressive symptoms, in people with chronic, recurrent depression or with resistance to treatment. For this reason, the main objective of this report is to investigate the effectiveness of MBCT in reducing depressive symptoms. A search was carried out in the Web of Science, EBSCOhost, SCOPUS and ProQuest databases, following the PRISMA criteria, where 10 articles that investigated the effectiveness of MBCT on depression were selected; either as exclusive therapy or complementary to other treatments. In the results, it was found that MBCT is effective in reducing depressive symptoms, both major and recurrent depression, in people with chronic, recurrent depression or with resistance to treatment. As secondary results, MBCT contributes to better levels of protective factors such as self-compassion and mindfulness skills

    Interaction of Cannabis Use Disorder and Striatal Connectivity in Antipsychotic Treatment Response

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    Antipsychotic (AP) medications are the mainstay for the treatment of schizophrenia spectrum disorders (SSD), but their efficacy is unpredictable and widely variable. Substantial efforts have been made to identify prognostic biomarkers that can be used to guide optimal prescription strategies for individual patients. Striatal regions involved in salience and reward processing are disrupted as a result of both SSD and cannabis use, and research demonstrates that striatal circuitry may be integral to response to AP drugs. In the present study, we used functional magnetic resonance imaging (fMRI) to investigate the relationship between a history of cannabis use disorder (CUD) and a striatal connectivity index (SCI), a previously developed neural biomarker for AP treatment response in SSD. Patients were part of a 12-week randomized, double-blind controlled treatment study of AP drugs. A sample of 48 first-episode SSD patients with no more than 2 weeks of lifetime exposure to AP medications, underwent a resting-state fMRI scan pretreatment. Treatment response was defined a priori as a binary (response/nonresponse) variable, and a SCI was calculated in each patient. We examined whether there was an interaction between lifetime CUD history and the SCI in relation to treatment response. We found that CUD history moderated the relationship between SCI and treatment response, such that it had little predictive value in SSD patients with a CUD history. In sum, our findings highlight that biomarker development can be critically impacted by patient behaviors that influence neurobiology, such as a history of CUD

    Perceived barriers and facilitators of exercise and healthy dietary choices : a study of employees and managers within a large transport organisation

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    Objective. The objective of the research was to examine employees’ perceived barriers and facilitators of physical activity and healthy dietary choices, and managers’ perceptions of how to facilitate physical activity and healthy dietary choices among their team members. Design. A cross-sectional and qualitative design was used. Setting. Participants were employees from a large public sector organisation (N= 121), who were asked about the barriers to and facilitators of maintaining regular exercise and healthy dietary choices. Managers were additionally asked about methods for facilitating physical activity and healthy dietary choices among their team members. Methods. The research used both quantitative and qualitative methodology, with categorical and open ended survey questions. Results. Thematic analysis revealed similar themes for both physical activity and healthy dietary choices, with participants citing working patterns, commuting times, family commitments, job characteristics, and lack of motivation as barriers to exercise and healthy dietary choices. Both employees and managers identified similar facilitators of exercise and healthy dietary choices, such as improved information, facilities, and working routines. Conclusion. The results provide an insight into the perceived barriers and facilitators to adopting a healthy lifestyle among a sample of employees with differing shift patterns and job roles. The results are discussed in relation to suggested methods for promoting physical activity and healthy dietary choices at work
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