489 research outputs found

    Molecular characterization of a new isolate of Borrelia lusitaniae derived from Apodemus sylvaticus in Portugal

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    A total of 196 small mammals were collected in Portugal and tested for Borrelia burgdorferi sensu lato. Tissue samples were taken from each animal and cultured in Barbour-Stoenner-Kelly (BSK)-II medium. The single strain of spirochete isolated was confirmed as Borrelia lusitaniae by genetic analyses. This is the first report of B. lusitaniae isolated from Apodemus sylvaticus

    Machine safety issues with respect to the extension of ECRH systems at ASDEX Upgrade

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    The beam intensity of electron cyclotron resonance heating at ASDEX Upgrade has the potential to seriously damage in-vessel components, whenever not fully absorbed by the plasma. Operation is, therefore, interlocked with both plasma current and density above a given threshold. Microwave protection detectors installed in several ports on the low field side switch the heating system off, in case the stray radiation exceeds a given threshold. During regular inspections, however, damages were reported in the vicinity of the launchers and in particular around the tiles of the heat shield. On one hand, it was found that insulating material, which may not face the plasma, degraded due to millimetre wave absorption. The waves entered the free space behind the heat shield through gaps. On the other hand, local damage even of metallic components was observed on surfaces, which were directly exposed to the microwave beam. Polarisation errors, which led to a local shine through of significant beam power, were responsible. We note that this happened mainly on the high field side in a certain distance to the microwave protection detectors, which were not triggered by the events. In order to increase the level of protection, we identify three necessary measures: Firstly, polarisation control is to be automated such, that mode content and shine through can be monitored. Secondly, by installing additional detectors, the spatial coverage of stray radiation monitoring is enlarged. Thirdly, the heat shield tiles will be redesigned in order to increase the shielding against millimetre waves

    Self-Regulation in a Web-Based Course: A Case Study

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    Little is known about how successful students in Web-based courses self-regulate their learning. This descriptive case study used a social cognitive model of self-regulated learning (SRL) to investigate how six graduate students used and adapted traditional SRL strategies to complete tasks and cope with challenges in a Web-based technology course; it also explored motivational and environmental influences on strategy use. Primary data sources were three transcribed interviews with each of the students over the course of the semester, a transcribed interview with the course instructor, and the students’ reflective journals. Archived course documents, including transcripts of threaded discussions and student Web pages, were secondary data sources. Content analysis of the data indicated that these students used many traditional SRL strategies, but they also adapted planning, organization, environmental structuring, help seeking, monitoring, record keeping, and self-reflection strategies in ways that were unique to the Web-based learning environment. The data also suggested that important motivational influences on SRL strategy use—self-efficacy, goal orientation, interest, and attributions—were shaped largely by student successes in managing the technical and social environment of the course. Important environmental influences on SRL strategy use included instructor support, peer support, and course design. Implications for online course instructors and designers, and suggestions for future research are offered

    Association of acute myeloid leukemias most immature phenotype with risk groups and outcomes

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    The precise phenotype and biology of acute myeloid leukemia stem cells remain controversial, in part because the “gold standard” immunodeficient mouse engraftment assay fails in a significant fraction of patients and identifies multiple cell-types in others. We sought to analyze the clinical utility of a novel assay for putative leukemia stem cells in a large prospective cohort. The leukemic clone’s most primitive hematopoietic cellular phenotype was prospectively identified in 109 newly-diagnosed acute myeloid leukemia patients, and analyzed against clinical risk groups and outcomes. Most (80/109) patients harbored CD34+CD38− leukemia cells. The CD34+CD38− leukemia cells in 47 of the 80 patients displayed intermediate aldehyde dehydrogenase expression, while normal CD34+CD38− hematopoietic stem cells expressed high levels of aldehyde dehydrogenase. In the other 33/80 patients, the CD34+CD38− leukemia cells exhibited high aldehyde dehydrogenase activity, and most (28/33, 85%) harbored poor-risk cytogenetics or FMS-like tyrosine kinase 3 internal tandem translocations. No CD34+ leukemia cells could be detected in 28/109 patients, including 14/21 patients with nucleophosmin-1 mutations and 6/7 acute promyelocytic leukemia patients. The patients with CD34+CD38− leukemia cells with high aldehyde dehydrogenase activity manifested a significantly lower complete remission rate, as well as poorer event-free and overall survivals. The leukemic clone’s most immature phenotype was heterogeneous with respect to CD34, CD38, and ALDH expression, but correlated with acute myeloid leukemia risk groups and outcomes. The strong clinical correlations suggest that the most immature phenotype detectable in the leukemia might serve as a biomarker for “clinically-relevant” leukemia stem cells. ClinicalTrials.gov: {"type":"clinical-trial","attrs":{"text":"NCT01349972","term_id":"NCT01349972"}}NCT01349972

    The P-SSP7 Cyanophage Has a Linear Genome with Direct Terminal Repeats

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    P-SSP7 is a T7-like phage that infects the cyanobacterium Prochlorococcus MED4. MED4 is a member of the high-light-adapted Prochlorococcus ecotypes that are abundant in the surface oceans and contribute significantly to primary production. P-SSP7 has become a model system for the investigation of T7-like phages that infect Prochlorococcus. It was classified as T7-like based on genome content and organization. However, because its genome assembled as a circular molecule, it was thought to be circularly permuted and to lack the direct terminal repeats found in other T7-like phages. Here we sequenced the ends of the P-SSP7 genome and found that the genome map is linear and contains a 206 bp repeat at both genome ends. Furthermore, we found that a 728 bp region of the genome originally placed downstream of the last ORF is actually located upstream of the first ORF on the genome map. These findings suggest that P-SSP7 is likely to use the direct terminal repeats for genome replication and packaging in a similar manner to other T7-like phages. Moreover, these results highlight the importance of experimentally verifying the ends of phage genomes, and will facilitate the use of P-SSP7 as a model for the correct assembly and end determination of the many T7-like phages isolated from the marine environment that are currently being sequenced

    Borrelia Burgdorferi Induces a Type I Interferon Response During Early Stages of Disseminated Infection in Mice

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    BACKGROUND: Lyme borrelia genotypes differ in their capacity to cause disseminated disease. Gene array analysis was employed to profile the host transcriptome induced by Borrelia burgdorferi strains with different capacities for causing disseminated disease in the blood of C3H/HeJ mice during early infection. RESULTS: B. burgdorferi B515, a clinical isolate that causes disseminated infection in mice, differentially regulated 236 transcripts (P \u3c 0.05 by ANOVA, with fold change of at least 2). The 216 significantly induced transcripts included interferon (IFN)-responsive genes and genes involved in immunity and inflammation. In contrast, B. burgdorferi B331, a clinical isolate that causes transient skin infection but does not disseminate in C3H/HeJ mice, stimulated changes in only a few genes (1 induced, 4 repressed). Transcriptional regulation of type I IFN and IFN-related genes was measured by quantitative RT-PCR in mouse skin biopsies collected from the site of infection 24 h after inoculation with B. burgdorferi. The mean values for transcripts of Ifnb, Cxcl10, Gbp1, Ifit1, Ifit3, Irf7, Mx1, and Stat2 were found to be significantly increased in B. burgdorferi strain B515-infected mice relative to the control group. In contrast, transcription of these genes was not significantly changed in response to B. burgdorferi strain B331 or B31-4, a mutant that is unable to disseminate. CONCLUSIONS: These results establish a positive association between the disseminating capacity of B. burgdorferi and early type I IFN induction in a murine model of Lyme disease

    Genetic Variants of Ehrlichia phagocytophila1, Rhode Island and Connecticut

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    Primers were used to amplify a 561-bp region of the 16S rRNA gene of Ehrlichia phagocytophila from Ixodes scapularis ticks and small mammals collected in Rhode Island and Connecticut. DNA sequences for all 50 E. phagocytophila-positive samples collected from 1996 through 1998 in southwestern Connecticut were identical to the sequence reported for E. phagocytophila DNA from confirmed human cases. In contrast, the sequences from 92 of 123 E. phagocytophila-positive Rhode Island samples collected from 1996 through 1999 included several variants differing by 1-2 nucleotides from that in the agent infecting humans. While 11.9% of 67 E. phagocytophila-positive ticks collected during 1997 in Rhode Island harbored ehrlichiae with sequences identical to that of the human agent, 79.1% had a variant sequence not previously described. The low incidence of human ehrlichiosis in Rhode Island may in part result from interference by these variant ehrlichiae with maintenance and transmission of the true agent of human disease

    Randomized multicenter phase II study of flavopiridol (alvocidib), cytarabine, and mitoxantrone (FLAM) versus cytarabine/daunorubicin (7+3) in newly diagnosed acute myeloid leukemia

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    Serial studies have demonstrated that induction therapy with FLAM [flavopiridol (alvocidib) 50 mg/m2 days 1–3, cytarabine 667 mg/m2/day continuous infusion days 6–8, and mitoxantrone (FLAM) 40 mg/m2 day 9] yields complete remission rates of nearly 70% in newly diagnosed poor-risk acute myeloid leukemia. Between May 2011–July 2013, 165 newly diagnosed acute myeloid leukemia patients (age 18–70 years) with intermediate/adverse-risk cytogenetics were randomized 2:1 to receive FLAM or 7+3 (cytarabine 100 mg/m2/day continuous infusion days 1–7 and daunorubicin 90 mg/m2 days 1–3), across 10 institutions. Some patients on 7+3 with residual leukemia on day 14 received 5+2 (cytarabine 100 mg/m2/day continuous infusion days 1–5 and daunorubicin 45 mg/m2 days 1–2), whereas patients on FLAM were not re-treated based on day 14 bone marrow findings. The primary objective was to compare complete remission rates between one cycle of FLAM and one cycle of 7+3. Secondary end points included safety, overall survival and event-free survival. FLAM led to higher complete remission rates than 7+3 alone (70% vs. 46%; P=0.003) without an increase in toxicity, and this improvement persisted after 7+3+/−5+2 (70% vs. 57%; P=0.08). There were no significant differences in overall survival and event-free survival in both arms but post-induction strategies were not standardized. These results substantiate the efficacy of FLAM induction in newly diagnosed AML. A phase III study is currently in development. This study is registered with clinicaltrials.gov identifier: 01349972
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