2,090 research outputs found

    Common DNA methylation dynamics in endometriod adenocarcinoma and glioblastoma suggest universal epigenomic alterations in tumorigenesis

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    Trends in altered DNA methylation have been defined across human cancers, revealing global loss of methylation (hypomethylation) and focal gain of methylation (hypermethylation) as frequent cancer hallmarks. Although many cancers share these trends, little is known about the specific differences in DNA methylation changes across cancer types, particularly outside of promoters. Here, we present a comprehensive comparison of DNA methylation changes between two distinct cancers, endometrioid adenocarcinoma (EAC) and glioblastoma multiforme (GBM), to elucidate common rules of methylation dysregulation and changes unique to cancers derived from specific cells. Both cancers exhibit significant changes in methylation over regulatory elements. Notably, hypermethylated enhancers within EAC samples contain several transcription factor binding site clusters with enriched disease ontology terms highlighting uterine function, while hypermethylated enhancers in GBM are found to overlap active enhancer marks in adult brain. These findings suggest that loss of original cellular identity may be a shared step in tumorigenesis

    Factors Affecting Speech Discrimination in Children with Cochlear Implants: Evidence from Early-Implanted Infants

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    Background To learn words and acquire language, children must be able to discriminate and correctly perceive phonemes. Although there has been much research on the general language outcomes of children with cochlear implants (CIs), little is known about the development of speech perception with regard to specific speech processes, such as speech discrimination. Purpose The purpose of this study was to investigate the development of speech discrimination in infants with CIs and identify factors that might correlate with speech discrimination skills. Research Design Using a Hybrid Visual Habituation procedure, we tested infants with CIs on their ability to discriminate the vowel contrast /i/-/u/. We also gathered demographic and audiological information about each infant. Study Sample Children who had received CIs before 2 yr of age served as participants. We tested the children at two post cochlear implantation intervals: 2–4 weeks post CI stimulation (N = 17) and 6–9 mo post CI stimulation (N = 10). Data Collection and Analysis The infants’ mean looking times during the novel versus old trials of the experiment were measured. A linear regression model was used to evaluate the relationship between the normalized looking time difference and the following variables: chronological age, age at CI stimulation, gender, communication mode, and best unaided pure-tone average. Results We found that the best unaided pure-tone average predicted speech discrimination at the early interval. In contrast to some previous speech perception studies that included children implanted before 3 yr of age, age at CI stimulation did not predict speech discrimination performance. Conclusions The results suggest that residual acoustic hearing before implantation might facilitate speech discrimination during the early period post cochlear implantation; with more hearing experience, communication mode might have a greater influence on the ability to discriminate speech. This and other studies on age at cochlear implantation suggest that earlier implantation might not have as large an effect on speech perception as it does on other language skills

    Examining How Middle School Science Teachers Implement a Multimedia-enriched Problem-based Learning Environment

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    This study examined how a group of ten middle school teachers implemented a technology enriched problem-based learning (PBL) environment. The goal was to understand their motivation, document their implementation techniques, and identify factors that teachers considered important in using technology-based PBL tools in their teaching. The analysis identified four factors that provided the impetus for teachers to consider the adoption of technology-based PBL instruction. These factors are (1) the PBL program addresses the teachers’ curricular needs and implementing it has campus administrative and technical support, (2) the method is aligned with teachers’ pedagogical beliefs, (3) the PBL program offers a new way of teaching and promotes the development of higher-order thinking skills, and (4) the PBL program challenges students in a captivating manner and supports the learning needs of all students. Teachers’ implementation techniques with over 1,000 sixth graders were documented in detail with regard to: 1) the teacher’s roles, 2) the student’s role, and 3) the classroom interactions during the implementation of the PBL program. In addition, a detailed description of contrasting narratives of two pairs of teachers is provided, illustrating the range of implementation techniques that can occur using the same PBL program to allow for individualized instruction to meet different students’ needs. The goal of providing detailed implementation practices is to address the lack of “how to” in PBL implementation in K-12 classrooms as indicated in the literature and offer insights and ideas to those interested in adopting and implementing PBL. Findings are discussed within the theoretical framework and implications are provided
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