626 research outputs found

    Speech intelligibility and prosody production in children with cochlear implants

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    Objectives—The purpose of the current study was to examine the relation between speech intelligibility and prosody production in children who use cochlear implants. Methods—The Beginner\u27s Intelligibility Test (BIT) and Prosodic Utterance Production (PUP) task were administered to 15 children who use cochlear implants and 10 children with normal hearing. Adult listeners with normal hearing judged the intelligibility of the words in the BIT sentences, identified the PUP sentences as one of four grammatical or emotional moods (i.e., declarative, interrogative, happy, or sad), and rated the PUP sentences according to how well they thought the child conveyed the designated mood. Results—Percent correct scores were higher for intelligibility than for prosody and higher for children with normal hearing than for children with cochlear implants. Declarative sentences were most readily identified and received the highest ratings by adult listeners; interrogative sentences were least readily identified and received the lowest ratings. Correlations between intelligibility and all mood identification and rating scores except declarative were not significant. Discussion—The findings suggest that the development of speech intelligibility progresses ahead of prosody in both children with cochlear implants and children with normal hearing; however, children with normal hearing still perform better than children with cochlear implants on measures of intelligibility and prosody even after accounting for hearing age. Problems with interrogative intonation may be related to more general restrictions on rising intonation, and th

    Ab initio study of hot electrons in GaAs

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    Hot carrier dynamics critically impacts the performance of electronic, optoelectronic, photovoltaic, and plasmonic devices. Hot carriers lose energy over nanometer lengths and picosecond timescales and thus are challenging to study experimentally, whereas calculations of hot carrier dynamics are cumbersome and dominated by empirical approaches. In this work, we present ab initio calculations of hot electrons in gallium arsenide (GaAs) using density functional theory and many-body perturbation theory. Our computed electron–phonon relaxation times at the onset of the Γ, L, and X valleys are in excellent agreement with ultrafast optical experiments and show that the ultrafast (tens of femtoseconds) hot electron decay times observed experimentally arise from electron–phonon scattering. This result is an important advance to resolve a controversy on hot electron cooling in GaAs. We further find that, contrary to common notions, all optical and acoustic modes contribute substantially to electron–phonon scattering, with a dominant contribution from transverse acoustic modes. This work provides definitive microscopic insight into hot electrons in GaAs and enables accurate ab initio computation of hot carriers in advanced materials

    Hearing, Perception, and Language in Clinical and Typical Populations

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    poster abstractThe IUPUI Signature Center for Advanced Studies in Hearing, Perception, and Language is a multidisciplinary, multidepartmental, multischool center dedicated to the integration of knowledge and methodologies from different disciplines to study speech perception and production, music perception and production, language, and cognition in clinical populations across the lifespan. Examples of ongoing research include the assessment of adult cochlear implant users’ perception of pitch; pediatric cochlear implant users’ speech intelligibility, prosody, and vocal music production; infants’ perception of auditory labels for visual objects; and breast cancer survivors’ perception of musical patterns following chemotherapy. In one study, we documented differences in hearing and music cognition between breast cancer survivors who received adjuvant cancer treatment and healthy age- and educationmatched controls. Participants were 29 female breast cancer survivors and 29 healthy controls. All participants received an audiometric test to assess hearing and The Montreal Battery for Evaluation of Amusia, which assesses such perceptual areas as melodic organization, temporal organization, and melodic memory. Results showed a moderate negative correlation between hearing and melodic organization scores across all subjects. For music cognition variables, effect-size analyses of melodic organization tasks (contour, intervals, tonality) suggested that healthy controls scored better than breast cancer survivors, although not significantly. The Center for Advanced Studies in Hearing, Perception, and Language continues to apply both standard and innovative analysis methodology to address cognitive issues of relevance to both clinical and typical populations

    Seasonal Variations in Air Pollution Particle-Induced Inflammatory Mediator Release and Oxidative Stress

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    Health effects associated with particulate matter (PM) show seasonal variations. We hypothesized that these heterogeneous effects may be attributed partly to the differences in the elemental composition of PM. Normal human bronchial epithelial (NHBE) cells and alveolar macrophages (AMs) were exposed to equal mass of coarse [PM with aerodynamic diameter of 2.5–10 μm (PM(2.5–10))], fine (PM(2.5)), and ultrafine (PM (< 0.1)) ambient PM from Chapel Hill, North Carolina, during October 2001 (fall) and January (winter), April (spring), and July (summer) 2002. Production of interleukin (IL)-8, IL-6, and reactive oxygen species (ROS) was measured. Coarse PM was more potent in inducing cytokines, but not ROSs, than was fine or ultrafine PM. In AMs, the October coarse PM was the most potent stimulator for IL-6 release, whereas the July PM consistently stimulated the highest ROS production measured by dichlorofluorescein acetate and dihydrorhodamine 123 (DHR). In NHBE cells, the January and the October PM were consistently the strongest stimulators for IL-8 and ROS, respectively. The July PM increased only ROS measured by DHR. PM had minimal effects on chemiluminescence. Principal-component analysis on elemental constituents of PM of all size fractions identified two factors, Cr/Al/Si/Ti/Fe/Cu and Zn/As/V/Ni/Pb/Se, with only the first factor correlating with IL-6/IL-8 release. Among the elements in the first factor, Fe and Si correlated with IL-6 release, whereas Cr correlated with IL-8 release. These positive correlations were confirmed in additional experiments with PM from all 12 months. These results indicate that elemental constituents of PM may in part account for the seasonal variations in PM-induced adverse health effects related to lung inflammation

    Personalizing dental screening and prevention protocols in dentulous patients with oropharyngeal cancer undergoing radiotherapy:A retrospective cohort study

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    Objectives:Patients with head and neck cancer are routinely screened for dental foci prior to radiotherapy (RT) to prevent post- RT tooth extractions associated with an increased risk of osteoradionecrosis. We evaluated the risk factors for post-RT tooth extraction to personalise dental screening and prevention protocols prior to RT. Materials and methods: This retrospective cohort study included dentulous patients diagnosed with oropharyngeal cancer who had undergone radiation therapy at doses 60–70 Gy and achieved a disease-free survival of ≥ 1 year (N = 174). Risk factors were assessed using Cox regression models. Results: The cumulative incidence of post-RT tooth extraction was 30.7 % at 5 years. Main indications for extraction (n = 62) were radiation caries (n = 20) and periodontal disease (n = 27). Risk factors associated (p &lt; 0.05) with radiation caries-related extractions included active smoking, alcohol abuse, poor oral hygiene, parotid gland irradiation, and mandibular irradiation. A high-dose volume in the mandible was associated with periodontal disease events. Conclusion: Post-RT extractions due to radiation caries were influenced by lifestyle factors and RT dose in the mandible and parotid glands. Periodontal disease-related extractions were primarily associated with the mandibular dose. During dental screening these post-RT risk factors should be taken into account to prevent osteoradionecrosis.</p

    Do ceramic femoral heads reduce taper fretting corrosion in hip arthroplasty? A retrieval study.

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    BACKGROUND: Previous studies regarding modular head-neck taper corrosion were largely based on cobalt chrome (CoCr) alloy femoral heads. Less is known about head-neck taper corrosion with ceramic femoral heads. QUESTIONS/PURPOSES: We asked (1) whether ceramic heads resulted in less taper corrosion than CoCr heads; (2) what device and patient factors influence taper fretting corrosion; and (3) whether the mechanism of taper fretting corrosion in ceramic heads differs from that in CoCr heads. METHODS: One hundred femoral head-stem pairs were analyzed for evidence of fretting and corrosion using a visual scoring technique based on the severity and extent of fretting and corrosion damage observed at the taper. A matched cohort design was used in which 50 ceramic head-stem pairs were matched with 50 CoCr head-stem pairs based on implantation time, lateral offset, stem design, and flexural rigidity. RESULTS: Fretting and corrosion scores were lower for the stems in the ceramic head cohort (p=0.03). Stem alloy (p=0.004) and lower stem flexural rigidity (Spearman\u27s rho=-0.32, p=0.02) predicted stem fretting and corrosion damage in the ceramic head cohort but not in the metal head cohort. The mechanism of mechanically assisted crevice corrosion was similar in both cohorts although in the case of ceramic femoral heads, only one of the two surfaces (the male metal taper) engaged in the oxide abrasion and repassivation process. CONCLUSIONS: The results suggest that by using a ceramic femoral head, CoCr fretting and corrosion from the modular head-neck taper may be mitigated but not eliminated. CLINICAL RELEVANCE: The findings of this study support further study of the role of ceramic heads in potentially reducing femoral taper corrosion

    Somatic Mutations of PIK3R1 Promote Gliomagenesis

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    The phosphoinositide 3-kinase (PI3K) pathway is targeted for frequent alteration in glioblastoma (GBM) and is one of the core GBM pathways defined by The Cancer Genome Atlas. Somatic mutations of PIK3R1 are observed in multiple tumor types, but the tumorigenic activity of these mutations has not been demonstrated in GBM. We show here that somatic mutations in the iSH2 domain of PIK3R1 act as oncogenic driver events. Specifically, introduction of a subset of the mutations identified in human GBM, in the nSH2 and iSH2 domains, increases signaling through the PI3K pathway and promotes tumorigenesis of primary normal human astrocytes in an orthotopic xenograft model. Furthermore, we show that cells that are dependent on mutant P85α-mediated PI3K signaling exhibit increased sensitivity to a small molecule inhibitor of AKT. Together, these results suggest that GBM patients whose tumors carry mutant PIK3R1 alleles may benefit from treatment with inhibitors of AKT

    Patient-centric trials for therapeutic development in precision oncology

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    An enhanced understanding of the molecular pathology of disease gained from genomic studies is facilitating the development of treatments that target discrete molecular subclasses of tumours. Considerable associated challenges include how to advance and implement targeted drug-development strategies. Precision medicine centres on delivering the most appropriate therapy to a patient on the basis of clinical and molecular features of their disease. The development of therapeutic agents that target molecular mechanisms is driving innovation in clinical-trial strategies. Although progress has been made, modifications to existing core paradigms in oncology drug development will be required to realize fully the promise of precision medicine

    Novel Murine Glioblastoma Models That Reflect the Immunotherapy Resistance Profile of a Human Disease

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    BACKGROUND: The lack of murine glioblastoma models that mimic the immunobiology of human disease has impeded basic and translational immunology research. We, therefore, developed murine glioblastoma stem cell lines derived from Nestin-CreERT2QkL/L; Trp53L/L; PtenL/L (QPP) mice driven by clinically relevant genetic mutations common in human glioblastoma. This study aims to determine the immune sensitivities of these QPP lines in immunocompetent hosts and their underlying mechanisms. METHODS: The differential responsiveness of QPP lines was assessed in the brain and flank in untreated, anti-PD-1, or anti-CTLA-4 treated mice. The impact of genomic landscape on the responsiveness of each tumor was measured through whole exome sequencing. The immune microenvironments of sensitive (QPP7) versus resistant (QPP8) lines were compared in the brain using flow cytometry. Drivers of flank sensitivity versus brain resistance were also measured for QPP8. RESULTS: QPP lines are syngeneic to C57BL/6J mice and demonstrate varied sensitivities to T cell immune checkpoint blockade ranging from curative responses to complete resistance. Infiltrating tumor immune analysis of QPP8 reveals improved T cell fitness and augmented effector-to-suppressor ratios when implanted subcutaneously (sensitive), which are absent on implantation in the brain (resistant). Upregulation of PD-L1 across the myeloid stroma acts to establish this state of immune privilege in the brain. In contrast, QPP7 responds to checkpoint immunotherapy even in the brain likely resulting from its elevated neoantigen burden. CONCLUSIONS: These syngeneic QPP models of glioblastoma demonstrate clinically relevant profiles of immunotherapeutic sensitivity and potential utility for both mechanistic discovery and evaluation of immune therapies

    Ambient-aware continuous care through semantic context dissemination

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    Background: The ultimate ambient-intelligent care room contains numerous sensors and devices to monitor the patient, sense and adjust the environment and support the staff. This sensor-based approach results in a large amount of data, which can be processed by current and future applications, e. g., task management and alerting systems. Today, nurses are responsible for coordinating all these applications and supplied information, which reduces the added value and slows down the adoption rate. The aim of the presented research is the design of a pervasive and scalable framework that is able to optimize continuous care processes by intelligently reasoning on the large amount of heterogeneous care data. Methods: The developed Ontology-based Care Platform (OCarePlatform) consists of modular components that perform a specific reasoning task. Consequently, they can easily be replicated and distributed. Complex reasoning is achieved by combining the results of different components. To ensure that the components only receive information, which is of interest to them at that time, they are able to dynamically generate and register filter rules with a Semantic Communication Bus (SCB). This SCB semantically filters all the heterogeneous care data according to the registered rules by using a continuous care ontology. The SCB can be distributed and a cache can be employed to ensure scalability. Results: A prototype implementation is presented consisting of a new-generation nurse call system supported by a localization and a home automation component. The amount of data that is filtered and the performance of the SCB are evaluated by testing the prototype in a living lab. The delay introduced by processing the filter rules is negligible when 10 or fewer rules are registered. Conclusions: The OCarePlatform allows disseminating relevant care data for the different applications and additionally supports composing complex applications from a set of smaller independent components. This way, the platform significantly reduces the amount of information that needs to be processed by the nurses. The delay resulting from processing the filter rules is linear in the amount of rules. Distributed deployment of the SCB and using a cache allows further improvement of these performance results
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