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  • 1
    Language: English
    In: Lasers in surgery and medicine, November 2014, Vol.46(9), pp.712-7
    Description: Moraxella catarrhalis is a significant cause of pediatric otitis media (OM), which is the most prevalent bacterial infection in children and primary reason for antibiotic administration in this population. Moreover, biofilm formation has been implicated as a primary mechanism of chronic or recurrent OM disease. As bacterial biofilms are inherently resistant to most antibiotics and these complex structures also present a significant challenge to the immune system, there is a clear need to identify novel antimicrobial approaches to treat OM infections. In this study, we evaluated the potential efficacy of antibacterial photodynamic therapy (aPDT) with porfimer sodium (Photofrin (PF)) against planktonic as well as biofilm-associated M. catarrhalis. The bactericidal activity of aPDT with PF was assessed against multiple recent clinical isolates of M. catarrhalis grown planktonically as well as in biofilms. The bactericidal activity of PF-aPDT was quantified by enumeration of colony forming units post-treatment. The effect of aPDT on M. catarrhalis biofilms was further investigated with scanning electron microscopy (SEM) imaging. aPDT with PF significantly reduced M. catarrhalis viability. Although PF-aPDT caused higher killing in planktonic grown organisms (5-6 log kill), biofilm grown bacteria also demonstrated a statistically significant reduction in viable organisms (3-4 log decrease in recoverable bacteria) following treatment as compared to saline only controls (P 〈 0.01). SEM studies indicated the PF-aPDT treated bacteria exhibited prominent morphological changes with visibly distorted cell membranes. aPDT with PF elicits significant bactericidal activity against both planktonic and biofilm-associated M. catarrhalis, suggesting this technology warrants further analysis as a potential novel antimicrobial treatment for acute or recurrent OM.
    Keywords: Antimicrobial Photodynamic Therapy ; Biofilm ; Gram-Negative Bacteria ; Otitis Media ; Photofrin ; Photochemotherapy ; Biofilms -- Drug Effects ; Dihematoporphyrin Ether -- Pharmacology ; Moraxella (Branhamella) Catarrhalis -- Drug Effects ; Photosensitizing Agents -- Pharmacology
    ISSN: 01968092
    E-ISSN: 1096-9101
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  • 2
    Language: English
    In: International Journal of Science Education, 03 May 2017, Vol.39(7), pp.814-839
    Description: One aim of school science instruction is to help students become adaptive problem solvers. Though successful at structuring novice problem solving, step-by-step problem-solving frameworks may also constrain students' thinking. This study utilises a paradigm established by Heckler [(2010). Some...
    Keywords: Problem Solving ; Epistemology ; Physics Education ; Education ; Sciences (General)
    ISSN: 0950-0693
    E-ISSN: 1464-5289
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  • 3
    Description: A central aim of physics education research is to understand the processes of learning and use that understanding to inform instruction. To this end, researchers often conduct studies to measure the effect of classroom interventions on student learning outcomes. Many of these intervention studies have provided an empirical foundation of reformed teaching techniques, such as active engagement. However, many times there is not sufficient evidence to conclude that the intervention had the intended effect, and these null results often end up in the file drawer. In this paper, we argue that null results can contribute significantly to physics education research, even if the results are not statistically significant. First, we review social sciences and biomedical research that has found widespread publication bias against null results, exploring why it occurs and how it can hurt the field. We then present three cases from physics education research to highlight how studies that yield null results can contribute to our understanding of teaching and learning. Finally, we distill from these studies some general principles for learning from null results, proposing that we should evaluate them not on whether they reject the null hypothesis, but according to their potential for generating new understanding. Comment: 14 pages, 3 figures, 1 table
    Keywords: Physics - Physics Education
    Source: Cornell University
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  • 4
    Language: English
    In: Nature (London), 01 November 2017, Vol.551
    Description: Our growing awareness of the importance and diversity of the microbial world contrasts starkly with our limited understanding of its fundamental structure. Despite remarkable advances in DNA sequence generation, a lack of standardized protocols and common analytical framework impede useful comparison between studies, hindering development of global inferences about microbial life on Earth. Here, we show that with coordinated protocols, exact microbial 16S rRNA gene sequences can be followed across scores of individual studies, revealing patterns of diversity, community structure, and life history strategy at a planetary scale. Using 27,751 crowdsourced environmental samples comprising more than 2.2 billion reads, we find sharp divides between host-associated and free-living communities. We show that the distribution of taxonomic and sequence diversity follows consistent trends across samples types and along gradients of environmental parameters, highlighting some of the global evolutionary patterns and ecological principles that underpin Earth’s microbiome. Here, this dataset provides the most complete environmental survey of our microbial world to date, and serves as a growing reference to provide immediate global context to future microbial surveys.
    Keywords: Environmental Sciences ; Microbiome ; Earth ; Global ; Basic Biological Sciences ; Sciences (General) ; Environmental Sciences ; Physics
    ISSN: 0028-0836
    E-ISSN: 1476-4687
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  • 5
    Language: English
    In: Physical Review Physics Education Research, 2019, Vol.15(2)
    Description: A central aim of physics education research is to understand the processes of learning and use that understanding to inform instruction. To this end, researchers often conduct studies to measure the effect of classroom interventions on student outcomes. Many of these intervention studies have...
    Keywords: Physics ; Outcomes of Education ; Probability ; Teaching Methods ; Intervention ; Case Studies ; Social Science Research ; Biomedicine ; Hypothesis Testing ; Educational Research ; Scientific Concepts ; Science Instruction ; Physics
    ISSN: 2469-9896
    E-ISSN: 2469-9896
    Source: ERIC (U.S. Dept. of Education)
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  • 6
    Language: English
    In: Advances in High Energy Physics, 01 June 2014, Vol.2014
    Description: The MAJORANA DEMONSTRATOR will search for the neutrinoless double-beta (ββ(0ν)) decay of the isotope 76Ge with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate that the neutrino is its own antiparticle, demonstrate that lepton number is not conserved, and provide information on the absolute mass scale of the neutrino. The DEMONSTRATOR is being assembled at the 4850-foot level of the Sanford Underground Research Facility in Lead, South Dakota. The array will be situated in a low-background environment and surrounded by passive and active shielding. Here we describe the science goals of the DEMONSTRATOR and the details of its design.
    Keywords: Neutrinos ; Colleges & Universities ; Laboratories ; Particle Accelerators ; Lawrence Berkeley National Laboratory;
    ISSN: 1687-7357
    E-ISSN: 16877365
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  • 7
    Language: English
    In: 24 March 2014
    Description: The Majorana Demonstrator will search for the neutrinoless double-beta decay (0*) of the 76Ge isotope with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate the neutrino is its own anti-particle, demonstrate that lepton number is not conserved, and provide information on the absolute mass-scale of the neutrino. The Demonstrator is being assembled at the 4850 foot level of the Sanford Underground Research Facility in Lead, South Dakota. The array will be contained in a lowbackground environment and surrounded by passive and active shielding. The goals for the Demonstrator are: demonstrating a background rate less than 3 counts tonne -1 year-1 in the 4 keV region of interest (ROI) surrounding the 2039 keV 76Ge endpoint energy; establishing the technology required to build a tonne-scale germanium based double-beta decay experiment; testing the recent claim of observation of 0; and performing a direct search for lightWIMPs (3-10 GeV/c2).
    Keywords: Physics;
    ISSN: 17426588
    E-ISSN: 17426596
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