421 research outputs found

    Systematic review of the effectiveness and cost-effectiveness of HealOzoneÂŽ for the treatment of occlusal pit/fissure caries and root caries

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    Objectives: To assess the effectiveness and cost-effectiveness of HealOzone® (CurOzone USA Inc., Ontario, Canada) for the management of pit and fissure caries, and root caries. The complete HealOzone procedure involves the direct application of ozone gas to the caries lesion on the tooth surface, the use of a remineralising solution immediately after application of ozone and the supply of a ‘patient kit’, which consists of toothpaste, oral rinse and oral spray all containing fluoride. Data sources: Electronic databases up to May 2004 (except Conference Papers Index, which were searched up to May 2002). Review methods: A systematic review of the effectiveness of HealOzone for the management of tooth decay was carried out. A systematic review of existing economic evaluations of ozone for dental caries was also planned but no suitable studies were identified. The economic evaluation included in the industry submission was critically appraised and summarised. A Markov model was constructed to explore possible cost-effectiveness aspects of HealOzone in addition to current management of dental caries. Results: Five full-text reports and five studies published as abstracts met the inclusion criteria. The five full-text reports consisted of two randomised controlled trials (RCTs) assessing the use of HealOzone for the management of primary root caries and two doctoral theses of three unpublished randomised trials assessing the use of HealOzone for the management of occlusal caries. Of the abstracts, four assessed the effects of HealOzone for the management of occlusal caries and one the effects of HealOzone for the management of root caries. Overall, the quality of the studies was modest, with many important methodological aspects not reported (e.g. concealment of allocation, blinding procedures, compliance of patients with home treatment). In particular, there were some concerns about the choice of statistical analyses. In most of the full-text studies analyses were undertaken at lesion level, ignoring the clustering of lesions within patients. The nature of the methodological concerns was sufficient to raise doubts about the validity of the included studies’ findings. A quantitative synthesis of results was deemed inappropriate. On the whole, there is not enough evidence from published RCTs on which to judge the effectiveness of ozone for the management of both occlusal and root caries. The perspective adopted for the study was that of the NHS and Personal Social Services. The analysis, carried out over a 5-year period, indicated that treatment using current management plus HealOzone cost more than current management alone for non-cavitated pit and fissure caries (£40.49 versus £24.78), but cost less for non-cavitated root caries (£14.63 versus £21.45). Given the limitations of the calculations these figures should be regarded as illustrative, not definitive. It was not possible to measure health benefits in terms of quality-adjusted life-years, due to uncertainties around the evidence of clinical effectiveness, and to the fact that the adverse events avoided are transient (e.g. pain from injection of local anaesthetic, fear of the drill). One-way sensitivity analysis was applied to the model. However, owing to the limitations of the economic analysis, this should be regarded as merely speculative. For non-cavitated pit and fissure caries, the HealOzone option was always more expensive than current management when the probability of cure using the HealOzone option was 70% or lower. For non-cavitated root caries the costs of the HealOzone comparator were lower than those of current management only when cure rates from HealOzone were at least 80%. The costs of current management were higher than those of the HealOzone option when the cure rate for current management was 40% or lower. One-way sensitivity analysis was also performed using similar NHS Statement of Dental Remuneration codes to those that are used in the industry submission. This did not alter the results for non-cavitated pit fissure caries as the discounted net present value of current management remained lower than that of the HealOzone comparator (£22.65 versus £33.39). Conclusions: Any treatment that preserves teeth and avoids fillings is welcome. However, the current evidence base for HealOzone is insufficient to conclude that it is a cost-effective addition to the management and treatment of occlusal and root caries. To make a decision on whether HealOzone is a cost-effective alternative to current preventive methods for the management of dental caries, further research into its clinical effectiveness is required. Independent RCTs of the effectiveness and cost-effectiveness of HealOzone for the management of occlusal caries and root caries need to be properly conducted with adequate design, outcome measures and methods for statistical analyses

    IL-22 mediates goblet cell hyperplasia and worm expulsion in intestinal helminth infection.

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    Type 2 immune responses are essential in protection against intestinal helminth infections. In this study we show that IL-22, a cytokine important in defence against bacterial infections in the intestinal tract, is also a critical mediator of anti-helminth immunity. After infection with Nippostrongylus brasiliensis, a rodent hookworm, IL-22-deficient mice showed impaired worm expulsion despite normal levels of type 2 cytokine production. The impaired worm expulsion correlated with reduced goblet cell hyperplasia and reduced expression of goblet cell markers. We further confirmed our findings in a second nematode model, the murine whipworm Trichuris muris. T.muris infected IL-22-deficient mice had a similar phenotype to that seen in N.brasiliensis infection, with impaired worm expulsion and reduced goblet cell hyperplasia. Ex vivo and in vitro analysis demonstrated that IL-22 is able to directly induce the expression of several goblet cell markers, including mucins. Taken together, our findings reveal that IL-22 plays an important role in goblet cell activation, and thus, a key role in anti-helminth immunity

    Layer-by-layer deposition of open-pore mesoporous TiO 2- NafionÂŽ film electrodes

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    The formation of variable thickness TiO2 nanoparticle-Nafion® composite films with open pores is demonstrated via a layer-by-layer deposition process. Films of about 6 nm diameter TiO2 nanoparticles grow in the presence of Nafion® by “clustering” of nanoparticles into bigger aggregates, and the resulting hierarchical structure thickens with about 25 nm per deposition cycle. Film growth is characterized by electron microscopy, atomic force microscopy, and quartz crystal microbalance techniques. Simultaneous small-angle X-ray scattering and wide-angle X-ray scattering measurements for films before and after calcination demonstrate the effect of Nafion® binder causing aggregation. Electrochemical methods are employed to characterize the electrical conductivity and diffusivity of charge through the TiO2-Nafion® composite films. Characteristic electrochemical responses are observed for cationic redox systems (diheptylviologen2+/+, Ru(NH3)3+/2+6, and ferrocenylmethyl-trimethylammonium2+/+) immobilized into the TiO2-Nafion® nanocomposite material. Charge conduction is dependent on the type of redox system and is proposed to occur either via direct conduction through the TiO2 backbone (at sufficiently negative potentials) or via redox-center-based diffusion/electron hopping (at more positive potentials)

    Quantum state preparation and macroscopic entanglement in gravitational-wave detectors

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    Long-baseline laser-interferometer gravitational-wave detectors are operating at a factor of 10 (in amplitude) above the standard quantum limit (SQL) within a broad frequency band. Such a low classical noise budget has already allowed the creation of a controlled 2.7 kg macroscopic oscillator with an effective eigenfrequency of 150 Hz and an occupation number of 200. This result, along with the prospect for further improvements, heralds the new possibility of experimentally probing macroscopic quantum mechanics (MQM) - quantum mechanical behavior of objects in the realm of everyday experience - using gravitational-wave detectors. In this paper, we provide the mathematical foundation for the first step of a MQM experiment: the preparation of a macroscopic test mass into a nearly minimum-Heisenberg-limited Gaussian quantum state, which is possible if the interferometer's classical noise beats the SQL in a broad frequency band. Our formalism, based on Wiener filtering, allows a straightforward conversion from the classical noise budget of a laser interferometer, in terms of noise spectra, into the strategy for quantum state preparation, and the quality of the prepared state. Using this formalism, we consider how Gaussian entanglement can be built among two macroscopic test masses, and the performance of the planned Advanced LIGO interferometers in quantum-state preparation

    Searching for a Stochastic Background of Gravitational Waves with LIGO

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    The Laser Interferometer Gravitational-wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new limit is ΩGW<6.5×10−5\Omega_{\rm GW} < 6.5 \times 10^{-5}. This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background.Comment: 37 pages, 16 figure

    Joining the dots: Conditional pass and programmatic assessment enhances recognition of problems with professionalism and factors hampering student progress

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    <p>Abstract</p> <p>Background</p> <p>Programmatic assessment that looks across a whole year may contribute to better decisions compared with those made from isolated assessments alone. The aim of this study is to describe and evaluate a programmatic system to handle student assessment results that is aligned not only with learning and remediation, but also with defensibility. The key components are standards based assessments, use of "Conditional Pass", and regular progress meetings.</p> <p>Methods</p> <p>The new assessment system is described. The evaluation is based on years 4-6 of a 6-year medical course. The types of concerns staff had about students were clustered into themes alongside any interventions and outcomes for the students concerned. The likelihoods of passing the year according to type of problem were compared before and after phasing in of the new assessment system.</p> <p>Results</p> <p>The new system was phased in over four years. In the fourth year of implementation 701 students had 3539 assessment results, of which 4.1% were Conditional Pass. More in-depth analysis for 1516 results available from 447 students revealed the odds ratio (95% confidence intervals) for failure was highest for students with problems identified in more than one part of the course (18.8 (7.7-46.2) p < 0.0001) or with problems with professionalism (17.2 (9.1-33.3) p < 0.0001). The odds ratio for failure was lowest for problems with assignments (0.7 (0.1-5.2) NS). Compared with the previous system, more students failed the year under the new system on the basis of performance during the year (20 or 4.5% compared with four or 1.1% under the previous system (p < 0.01)).</p> <p>Conclusions</p> <p>The new system detects more students in difficulty and has resulted in less "failure to fail". The requirement to state conditions required to pass has contributed to a paper trail that should improve defensibility. Most importantly it has helped detect and act on some of the more difficult areas to assess such as professionalism.</p

    A new model for root growth in soil with macropores

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    Abstract: Background and aimsThe use of standard dynamic root architecture models to simulate root growth in soil containing macropores failed to reproduce experimentally observed root growth patterns. We thus developed a new, more mechanistic model approach for the simulation of root growth in structured soil. Methods: In our alternative modelling approach, we distinguish between, firstly, the driving force for root growth, which is determined by the orientation of the previous root segment and the influence of gravitropism and, secondly, soil mechanical resistance to root growth. The latter is expressed by its inverse, soil mechanical conductance, and treated similarly to hydraulic conductivity in Darcy’s law. At the presence of macropores, soil mechanical conductance is anisotropic, which leads to a difference between the direction of the driving force and the direction of the root tip movement. Results: The model was tested using data from the literature, at pot scale, at macropore scale, and in a series of simulations where sensitivity to gravity and macropore orientation was evaluated. Conclusions: Qualitative and quantitative comparisons between simulated and experimentally observed root systems showed good agreement, suggesting that the drawn analogy between soil water flow and root growth is a useful one
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