1,704 research outputs found

    Translating three states of knowledge--discovery, invention, and innovation

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    <p>Abstract</p> <p>Background</p> <p>Knowledge Translation (KT) has historically focused on the proper use of knowledge in healthcare delivery. A knowledge base has been created through empirical research and resides in scholarly literature. Some knowledge is amenable to direct application by stakeholders who are engaged during or after the research process, as shown by the Knowledge to Action (KTA) model. Other knowledge requires multiple transformations before achieving utility for end users. For example, conceptual knowledge generated through science or engineering may become embodied as a technology-based invention through development methods. The invention may then be integrated within an innovative device or service through production methods. To what extent is KT relevant to these transformations? How might the KTA model accommodate these additional development and production activities while preserving the KT concepts?</p> <p>Discussion</p> <p>Stakeholders adopt and use knowledge that has perceived utility, such as a solution to a problem. Achieving a technology-based solution involves three methods that generate knowledge in three states, analogous to the three classic states of matter. Research activity generates discoveries that are intangible and highly malleable like a gas; development activity transforms discoveries into inventions that are moderately tangible yet still malleable like a liquid; and production activity transforms inventions into innovations that are tangible and immutable like a solid. The paper demonstrates how the KTA model can accommodate all three types of activity and address all three states of knowledge. Linking the three activities in one model also illustrates the importance of engaging the relevant stakeholders prior to initiating any knowledge-related activities.</p> <p>Summary</p> <p>Science and engineering focused on technology-based devices or services change the state of knowledge through three successive activities. Achieving knowledge implementation requires methods that accommodate these three activities and knowledge states. Accomplishing beneficial societal impacts from technology-based knowledge involves the successful progression through all three activities, and the effective communication of each successive knowledge state to the relevant stakeholders. The KTA model appears suitable for structuring and linking these processes.</p

    Use of the Meganuclease I-SceI of Saccharomyces cerevisiae to select for gene deletions in actinomycetes

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    The search for new natural products is leading to the isolation of novel actinomycete species, many of which will ultimately require genetic analysis. Some of these isolates will likely exhibit low intrinsic frequencies of homologous recombination and fail to sporulate under laboratory conditions, exacerbating the construction of targeted gene deletions and replacements in genetically uncharacterised strains. To facilitate the genetic manipulation of such species, we have developed an efficient method to generate gene or gene cluster deletions in actinomycetes by homologous recombination that does not introduce any other changes to the targeted organism's genome. We have synthesised a codon optimised I-SceI gene for expression in actinomycetes that results in the production of the yeast I-SceI homing endonuclease which produces double strand breaks at a unique introduced 18 base pair recognition sequence. Only those genomes that undergo homologous recombination survive, providing a powerful selection for recombinants, approximately half of which possess the desired mutant genotype. To demonstrate the efficacy and efficiency of the system, we deleted part of the gene cluster for the red-pigmented undecylprodiginine complex of compounds in Streptomyces coelicolor M1141. We believe that the system we have developed will be broadly applicable across a wide range of actinomycetes

    Ab-Externo AAV-Mediated Gene Delivery to the Suprachoroidal Space Using a 250 Micron Flexible Microcatheter

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    The current method of delivering gene replacement to the posterior segment of the eye involves a three-port pars plana vitrectomy followed by injection of the agent through a 37-gauge cannula, which is potentially wrought with retinal complications. In this paper we investigate the safety and efficacy of delivering adeno-associated viral (AAV) vector to the suprachoroidal space using an ab externo approach that utilizes an illuminated microcatheter.6 New Zealand White rabbits and 2 Dutch Belted rabbits were used to evaluate the ab externo delivery method. sc-AAV5-smCBA-hGFP vector was delivered into the suprachoroidal space using an illuminated iTrackTM 250A microcatheter. Six weeks after surgery, the rabbits were sacrificed and their eyes evaluated for AAV transfection using immunofluorescent antibody staining of GFP.Immunostaining of sectioned and whole-mounted eyes demonstrated robust transfection in all treated eyes, with no fluorescence in untreated control eyes. Transfection occurred diffusely and involved both the choroid and the retina. No apparent adverse effects caused by either the viral vector or the procedure itself could be seen either clinically or histologically.The ab externo method of delivery using a microcatheter was successful in safely and effectively delivering a gene therapy agent to the suprachoroidal space. This method presents a less invasive alternative to the current method of virally vectored gene delivery

    A Measurement of Rb using a Double Tagging Method

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    The fraction of Z to bbbar events in hadronic Z decays has been measured by the OPAL experiment using the data collected at LEP between 1992 and 1995. The Z to bbbar decays were tagged using displaced secondary vertices, and high momentum electrons and muons. Systematic uncertainties were reduced by measuring the b-tagging efficiency using a double tagging technique. Efficiency correlations between opposite hemispheres of an event are small, and are well understood through comparisons between real and simulated data samples. A value of Rb = 0.2178 +- 0.0011 +- 0.0013 was obtained, where the first error is statistical and the second systematic. The uncertainty on Rc, the fraction of Z to ccbar events in hadronic Z decays, is not included in the errors. The dependence on Rc is Delta(Rb)/Rb = -0.056*Delta(Rc)/Rc where Delta(Rc) is the deviation of Rc from the value 0.172 predicted by the Standard Model. The result for Rb agrees with the value of 0.2155 +- 0.0003 predicted by the Standard Model.Comment: 42 pages, LaTeX, 14 eps figures included, submitted to European Physical Journal

    Measurement of the running of the QED coupling in small-angle Bhabha scattering at LEP

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    Using the OPAL detector at LEP, the running of the effective QED coupling alpha(t) is measured for space-like momentum transfer from the angular distribution of small-angle Bhabha scattering. In an almost ideal QED framework, with very favourable experimental conditions, we obtain: Delta alpha(-6.07GeV^2) - Delta alpha(-1.81GeV^2) = (440 pm 58 pm 43 pm 30) X 10^-5, where the first error is statistical, the second is the experimental systematic and the third is the theoretical uncertainty. This agrees with current evaluations of alpha(t).The null hypothesis that alpha remains constant within the above interval of -t is excluded with a significance above 5sigma. Similarly, our results are inconsistent at the level of 3sigma with the hypothesis that only leptonic loops contribute to the running. This is currently the most significant direct measurment where the running alpha(t) is probed differentially within the measured t range.Comment: 43 pages, 12 figures, Submitted to Euro. Phys. J.

    Measurement of the B+ and B-0 lifetimes and search for CP(T) violation using reconstructed secondary vertices

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    The lifetimes of the B+ and B-0 mesons, and their ratio, have been measured in the OPAL experiment using 2.4 million hadronic Z(0) decays recorded at LEP. Z(0) --> b (b) over bar decays were tagged using displaced secondary vertices and high momentum electrons and muons. The lifetimes were then measured using well-reconstructed charged and neutral secondary vertices selected in this tagged data sample. The results aretau(B+) = 1.643 +/- 0.037 +/- 0.025 pstau(Bo) = 1.523 +/- 0.057 +/- 0.053 pstau(B+)/tau(Bo) = 1.079 +/- 0.064 +/- 0.041,where in each case the first error is statistical and the second systematic.A larger data sample of 3.1 million hadronic Z(o) decays has been used to search for CP and CPT violating effects by comparison of inclusive b and (b) over bar hadron decays, No evidence fur such effects is seen. The CP violation parameter Re(epsilon(B)) is measured to be Re(epsilon(B)) = 0.001 +/- 0.014 +/- 0.003and the fractional difference between b and (b) over bar hadron lifetimes is measured to(Delta tau/tau)(b) = tau(b hadron) - tau((b) over bar hadron)/tau(average) = -0.001 +/- 0.012 +/- 0.008

    Modeling the Afferent Dynamics of the Baroreflex Control System

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    In this study we develop a modeling framework for predicting baroreceptor firing rate as a function of blood pressure. We test models within this framework both quantitatively and qualitatively using data from rats. The models describe three components: arterial wall deformation, stimulation of mechanoreceptors located in the BR nerve-endings, and modulation of the action potential frequency. The three sub-systems are modeled individually following well-established biological principles. The first submodel, predicting arterial wall deformation, uses blood pressure as an input and outputs circumferential strain. The mechanoreceptor stimulation model, uses circumferential strain as an input, predicting receptor deformation as an output. Finally, the neural model takes receptor deformation as an input predicting the BR firing rate as an output. Our results show that nonlinear dependence of firing rate on pressure can be accounted for by taking into account the nonlinear elastic properties of the artery wall. This was observed when testing the models using multiple experiments with a single set of parameters. We find that to model the response to a square pressure stimulus, giving rise to post-excitatory depression, it is necessary to include an integrate-and-fire model, which allows the firing rate to cease when the stimulus falls below a given threshold. We show that our modeling framework in combination with sensitivity analysis and parameter estimation can be used to test and compare models. Finally, we demonstrate that our preferred model can exhibit all known dynamics and that it is advantageous to combine qualitative and quantitative analysis methods

    Age of Child, More than HPV Type, Is Associated with Clinical Course in Recurrent Respiratory Papillomatosis

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    Background: RRP is a devastating disease in which papillomas in the airway cause hoarseness and breathing difficulty. The disease is caused by human papillomavirus (HPV), 6 or 11 and is very variable. Patients undergo multiple surgeries to maintain a patent airway and in order to communicate vocally. Several small studies have been published in which most have noted that HPV 11 is associated with a more aggressive course. Methodology/Principal Findings: Papilloma biopsies were taken from patients undergoing surgical treatment of RRP and were subjected to HPV typing. 118 patients with juvenile-onset RRP with a least 1 year of clinical data and infected with a single HPV type were analyzed. HPV 11 was encountered in 40% of the patients. By our definition, most of the patients in the sample (81%) had run an aggressive course. The odds of a patient with HPV 11 running an aggressive course were 3.9 times higher that that of patients with HPV 6 (Fisher's exact p=0.017). However, clinical course was more closely associated with age of the patient (at diagnosis and at the time of the current surgery) than with HPV type. Patients with HPV 11 were diagnosed at a younger age (2.4y) than were those with HPV 6 (3.4y) (p=0.014). Both by multiple linear regression and by multiple logistics regression HPV type was only weakly associated with metrics of disease course when simultaneously accounting for age. Conclusions/Significance Abstract: The course of RRP is variable and a quarter of the variability can be accounted for by the age of the patient. HPV 11 is more closely associated with a younger age at diagnosis than it is associated with an aggressive clinical course. These data suggest that there are factors other than HPV type and age of the patient that determine disease course. © 2008 Buchinsky et al

    A Novel Role of RASSF9 in Maintaining Epidermal Homeostasis

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    The physiological role of RASSF9, a member of the Ras-association domain family (RASSF), is currently unclear. Here, we report a mouse line in which an Epstein-Barr virus Latent Membrane Protein 1 (LMP1) transgene insertion has created a 7.2-kb chromosomal deletion, which abolished RASSF9 gene expression. The RASSF9-null mice exhibited interesting phenotypes that resembled human ageing, including growth retardation, short lifespan, less subcutaneous adipose layer and alopecia. In the wild-type mice, RASSF9 is predominantly expressed in the epidermal keratinocytes of skin, as determined by quantitative reverse-transcription PCR, immunofluorescence and in situ hybridization. In contrast, RASSF9−/− mice presented a dramatic change in epithelial organization of skin with increased proliferation and aberrant differentiation as detected by bromodeoxyuridine incorporation assays and immunofluorescence analyses. Furthermore, characteristic functions of RASSF9−/− versus wild type (WT) mouse primary keratinocytes showed significant proliferation linked to a reduction of p21Cip1 expression under growth or early differentiation conditions. Additionally, in RASSF9−/− keratinocytes there was a drastic down-modulation of terminal differentiation markers, which could be rescued by infection with a recombinant adenovirus, Adv/HA-RASSF9. Our results indicate a novel and significant role of RASSF9 in epidermal homeostasis

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
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