637 research outputs found

    Fatigue crack growth and low cycle fatigue of two nickel base superalloys

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    The fatigue crack growth and low cycle fatigue behavior of two P/M superalloys, Rene 95 and Astroloy, in the hot isostatically pressed (HIP) condition, was determined. Test variables included frequency, temperature, environment, and hold times at peak tensile loads (or strains). Crack initiation sites were identified in both alloys. Crack growth rates were shown to increase in argon with decreasing frequency or with the imposition of hold times. This behavior was attributed to the effect of oxygen in the argon. Auger analyses were performed on oxide films formed in argon. Low cycle fatigue lives also were degraded by tensile hold, contrary to previous reports in the literature. The role of environment in low cycle fatigue behavior is discussed

    MutSα Binds to and Promotes Synapsis of Transcriptionally Activated Immunoglobulin Switch Regions

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    AbstractImmunoglobulin class switch recombination joins a new constant (C) region to the rearranged and expressed heavy chain variable (VDJ) region in antigen-activated B cells (Figure 1A) (reviewed in [1, 2]). Switch recombination is activated by transcription of intronic, G-rich and repetitive switch (S) regions and produces junctions that are heterogeneous in sequence and position in the S regions. Switch recombination depends upon the B cell-specific cytidine deaminase, AID, and conserved DNA repair factors, including the mismatch repair heterodimer, MutSα (MSH2/MSH6). In mice, ablation of Msh2 or Msh6, but not Msh3, decreases levels of switch recombination and diminishes heterogeneity of switch junctions [3–7]. Here, we demonstrate that MSH2 associates with transcribed S regions in primary murine B cells activated for switch recombination. Electron microscopic imaging reveals that MutSα binds in vitro to DNA structures formed within transcribed S regions and mediates their synapsis. MutSα binds with high affinity to G4 DNA formed upon transcription of the S regions and also binds to U·G mismatches, initial products of DNA deamination by AID. These results suggest that MutSα interacts with the S regions in switching B cells to promote DNA synapsis and recombination

    Using a state cancer registry to recruit young breast cancer survivors and high-risk relatives: protocol of a randomized trial testing the efficacy of a targeted versus a tailored intervention to increase breast cancer screening

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    Abstract Background The Michigan Prevention Research Center, the University of Michigan Schools of Nursing, Public Health, and Medicine, and the Michigan Department of Community Health propose a multidisciplinary academic-clinical practice three-year project to increase breast cancer screening among young breast cancer survivors and their cancer-free female relatives at greatest risk for breast cancer. Methods/design The study has three specific aims: 1) Identify and survey 3,000 young breast cancer survivors (diagnosed at 20–45 years old) regarding their breast cancer screening utilization. 2) Identify and survey survivors’ high-risk relatives regarding their breast cancer screening utilization. 3) Test two versions (Targeted vs. Enhanced Tailored) of an intervention to increase breast cancer screening among survivors and relatives. Following approval by human subjects review boards, 3,000 young breast cancer survivors will be identified through the Michigan Cancer Registry and mailed an invitation letter and a baseline survey. The baseline survey will obtain information on the survivors’: a) current breast cancer screening status and use of genetic counseling; b) perceived barriers and facilitators to screening; c) family health history. Based on the family history information provided by survivors, we will identify up to two high-risk relatives per survivor. Young breast cancer survivors will be mailed consent forms and baseline surveys to distribute to their selected high-risk relatives. Relatives’ baseline survey will obtain information on their: a) current breast cancer screening status and use of genetic counseling; and b) perceived barriers and facilitators to screening. Young breast cancer survivors and high-risk relatives will be randomized as a family unit to receive two versions of an intervention aiming to increase breast cancer screening and use of cancer genetic services. A follow-up survey will be mailed 9 months after the intervention to survivors and high-risk relatives to evaluate the efficacy of each intervention version on: a) use of breast cancer screening and genetic counseling; b) perceived barriers and facilitators to screening; c) self-efficacy in utilizing cancer genetic and screening services; d) family support related to screening; e) knowledge of breast cancer genetics; and f) satisfaction with the intervention. Discussion The study will enhance efforts of the state of Michigan surrounding cancer prevention, control, and public health genomics. Trial registration NCT01612338http://deepblue.lib.umich.edu/bitstream/2027.42/112835/1/12885_2012_Article_3739.pd

    Evaluation of a robot-assisted therapy for children with autism and intellectual disability

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    It is well established that robots can be suitable assistants in the care and treatment of children with Autism Spectrum Disorder (ASD). However, the majority of the research focuses on stand-alone interventions, high-functioning individuals and the success is evaluated via qualitative analysis of videos recorded during the interaction. In this paper, we present a preliminary evaluation of our on-going research on integrating robot-assisted therapy in the treatment of children with ASD and Intellectual Disability (ID), which is the most common case. The experiment described here integrates a robot-assisted imitation training in the standard treat‐ ment of six hospitalised children with various level of ID, who were engaged by a robot on imitative tasks and their progress assessed via a quantitative psycho- diagnostic tool. Results show success in the training and encourage the use of a robotic assistant in the care of children with ASD and ID with the exception of those with profound ID, who may need a different approach

    “I think there has to be a mutual respect for there to be value”: Evaluating patient engagement in a national clinical trial on de-implementation of low value care

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    Abstract Background The evaluation of patient engagement in research is understudied and under-reported, making it difficult to know what engagement strategies work best and when. We provide the results of an evaluation of patient engagement in a large Canadian research program focused on the de-implementation of low-value care. We aimed to evaluate the experience and impact of patient engagement in the study. Methods An online cross-sectional survey was administered using Microsoft Forms to (1) researchers and study staff and (2) patient partners. The survey was developed following iterative reviews by the project’s patient partnership council and evaluation committee. Survey content areas included opinions on patient engagement to date, including challenges to engagement and suggestions for improvement. Patient partners also evaluated the partnership council. Descriptive statistics including counts and percentages described Likert scale survey items, while open comments were analyzed using descriptive content analysis. Results The survey response rate was 46% (17/37). There were positive attitudes about the value of patient engagement in this project. There was also a high degree of willingness to be involved with patient engagement in future projects, whether as a patient partner or as a researcher including patients on the research team. Most patient partners felt their contributions to the project were valued by researchers and study research staff. Open comments revealed that a co-design approach and full inclusion on the research team were integral to demonstrating the value of patient partner input. Areas for improvement included more frequent and ongoing communication among all team members, as well as earlier training about patient engagement, particularly addressing role expectations and role clarity. Conclusions Our data revealed that despite some challenges, team members recognized the value of patient engagement in research and agreed project decisions had been impacted by patient partner input. Ongoing communication was highlighted as an area for improvement, as well as earlier training and ongoing support for all team members, but particularly researchers and study staff. In response to evaluation data, the team has reinstated a quarterly newsletter and plans to use specific patient engagement planning templates across study sites for all project activities. These tools should help make expectations clear for all team members and contribute to a positive patient engagement experience. Findings can inform patient engagement planning and evaluation for other health research projects.Plain English Summary Evaluating patient engagement in research is often not done or not reported, making it hard to know what engagement strategies work best and when. Here, we provide the results of an evaluation of patient engagement in a Canadian Institutes for Health Research (CIHR) Strategy for Patient Oriented Research (SPOR) Innovative Clinical Trial Multi-Year Grant. The project focuses on strategies to reduce two low-value care practices (pre-operative testing in low-risk day surgery and imaging for low back pain). An online survey was sent to project researchers, study staff and patient partners to get their opinions on the patient engagement in the project. Generally, there were positive attitudes about the value of patient engagement in the project. Both patient partners and research study staff were very willing to be involved with patient engagement in future projects. Most patient partners felt their contributions to the project were valued by researchers and study research staff. An important part of showing the value of patient partners was working together to design the project and making sure that the patient partners were considered full members of the research team. Areas for improvement included better communication among all team members and earlier training about patient engagement with a focus on patient roles and expectations. The results from this survey will be used to improve the patient engagement in this project but will also help patient engagement planning and evaluation for other health research projects

    Aberrant Splicing of the Senataxin Gene in a Patient with Ataxia with Oculomotor Apraxia Type 2

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    Ataxia with oculomotor apraxia type 2 (AOA2) is caused by a diversity of mutations within the coding region of the senataxin gene. Recently, rare noncoding senataxin mutations affecting RNA processing have been identified in AOA2. Here, we report the case of an 18-year-old woman, with classic clinical features of AOA2, who was found to harbor a mutation within senataxin intron 16. This mutation disrupts the local 5′ splice site architecture via a novel intronic frameshift mechanism, causing skipping of exon 16 with predicted disruption of the conserved DNA/RNA helicase domain. RNA processing mutations expand the growing complexity of pathogenic senataxin mutations

    Influence of N- methylation and conformation on almiramide anti-leishmanial activity

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    The almiramide N-methylated lipopeptides exhibit promising activity against trypanosomatid parasites. A structure–activity relationship study has been performed to examine the influences of N-methylation and conformation on activity against various strains of leishmaniasis protozoan and on cytotoxicity. The synthesis and biological analysis of twenty-five analogs demonstrated that derivatives with a single methyl group on either the first or fifth residue amide nitrogen exhibited greater activity than the permethylated peptides and relatively high potency against resistant strains. Replacement of amino amide residues in the peptide, by turn inducing α‑amino γ‑lactam (Agl) and N-aminoimidazalone (Nai) counterparts, reduced typically anti-parasitic activity; however, peptide amides possessing Agl residues at the second residue retained significant potency in the unmethylated and permethylated series. Systematic study of the effects of methylation and turn geometry on anti-parasitic activity indicated the relevance of an extended conformer about the central residues, and conformational mobility by tertiary amide isomerization and turn geometry at the extremities of the active peptides

    Molecular subtype analysis determines the association of advanced breast cancer in Egypt with favorable biology

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    <p>Abstract</p> <p>Background</p> <p>Prognostic markers and molecular breast cancer subtypes reflect underlying biological tumor behavior and are important for patient management. Compared to Western countries, women in North Africa are less likely to be prognosticated and treated based on well-characterized markers such as the estrogen receptor (ER), progesterone receptor (PR) and Her2. We conducted this study to determine the prevalence of breast cancer molecular subtypes in the North African country of Egypt as a measure of underlying biological characteristics driving tumor manifestations.</p> <p>Methods</p> <p>To determine molecular subtypes we characterized over 200 tumor specimens obtained from Egypt by performing ER, PR, Her2, CK5/6, EGFR and Ki67 immunohistochemistry.</p> <p>Results</p> <p>Our study demonstrated that the Luminal A subtype, associated with favorable prognosis, was found in nearly 45% of cases examined. However, the basal-like subtype, associated with poor prognosis, was found in 11% of cases. These findings are in sharp contrast to other parts of Africa in which the basal-like subtype is over-represented.</p> <p>Conclusions</p> <p>Egyptians appear to have favorable underlying biology, albeit having advanced disease at diagnosis. These data suggest that Egyptians would largely profit from early detection of their disease. Intervention at the public health level, including education on the benefits of early detection is necessary and would likely have tremendous impact on breast cancer outcome in Egypt.</p

    Negative Supercoiling Creates Single-Stranded Patches of DNA That Are Substrates for AID–Mediated Mutagenesis

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    Antibody diversification necessitates targeted mutation of regions within the immunoglobulin locus by activation-induced cytidine deaminase (AID). While AID is known to act on single-stranded DNA (ssDNA), the source, structure, and distribution of these substrates in vivo remain unclear. Using the technique of in situ bisulfite treatment, we characterized these substrates—which we found to be unique to actively transcribed genes—as short ssDNA regions, that are equally distributed on both DNA strands. We found that the frequencies of these ssDNA patches act as accurate predictors of AID activity at reporter genes in hypermutating and class switching B cells as well as in Escherichia coli. Importantly, these ssDNA patches rely on transcription, and we report that transcription-induced negative supercoiling enhances both ssDNA tract formation and AID mutagenesis. In addition, RNaseH1 expression does not impact the formation of these ssDNA tracts indicating that these structures are distinct from R-loops. These data emphasize the notion that these transcription-generated ssDNA tracts are one of many in vivo substrates for AID
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