1,905 research outputs found

    Transcultural adaptation of the who oral health questionnaire and its validation in chilean children

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    Indexación: Scopus.Introduction: The last edition of the WHO "Oral Health Questionnaire for Children" was published in 2013. This is an only-English version, and as such it requires linguistic adaptation and validation to be applied in the Chilean population. Objectives: To translate and adapt the WHO Oral Health Questionnaire for Children to Spanish and validate it in a Chilean population. Methods: A translation and back translation of the original instrument from English to Spanish was carried out by four translators. The questionnaire was self-reported as a pilot test in ten individuals. A sample was subsequently selected for convenience taking into account the population distribution, resulting in a final sample of 103 individuals. The internal consistency was calculated with Cronbach's alpha, criterion validity with Pearson's correlation coefficient and construct validity with Exploratory Factor Analysis. Results: A conceptual and semantic equivalence of the instrument was obtained. Women and men accounted for 43.69% and 56.31% of the sample, respectively. Cronbach's alpha coefficient was 0.62, while criterion validity was slightly positive between the total dimensions and the DMFT (r=0.13, p-value= 0.20). The Exploratory Factor Analysis yielded a total of 11 factors that explain 70% of the variability in the data. Conclusions: The oral health questionnaire has been appropriately adapted to Spanish, having conceptual as well as semantic equivalence to the original version, being reliable and valid to be used in a population of 12-year-old Chilean children. © 2018, Universidad de Concepcion. All rights reserved.http://joralres.com/index.php/JOR/article/view/432/43

    Plantinga-Vegter algorithm takes average polynomial time

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    We exhibit a condition-based analysis of the adaptive subdivision algorithm due to Plantinga and Vegter. The first complexity analysis of the PV Algorithm is due to Burr, Gao and Tsigaridas who proved a O(2τd4log⁡d)O\big(2^{\tau d^{4}\log d}\big) worst-case cost bound for degree dd plane curves with maximum coefficient bit-size τ\tau. This exponential bound, it was observed, is in stark contrast with the good performance of the algorithm in practice. More in line with this performance, we show that, with respect to a broad family of measures, the expected time complexity of the PV Algorithm is bounded by O(d7)O(d^7) for real, degree dd, plane curves. We also exhibit a smoothed analysis of the PV Algorithm that yields similar complexity estimates. To obtain these results we combine robust probabilistic techniques coming from geometric functional analysis with condition numbers and the continuous amortization paradigm introduced by Burr, Krahmer and Yap. We hope this will motivate a fruitful exchange of ideas between the different approaches to numerical computation.Comment: 8 pages, correction of typo

    Genetic and Molecular Factors in Drug-Induced Liver Injury: A Review

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    The diagnosis of drug-induced liver injury (DILI) is challenging and based on complex diagnostic criteria. DILI falls into two main categories i) intrinsic 'dose-dependent' Type A reactions ii) 'idiosyncratic' or Type B reactions (which are usually not predictable). Idiosyncratic reactions can be immunoallergic (hypersensitivity), or metabolic, although overlap between categories can occur. The aim of this review is to summarise the general view of underlying mechanisms in DILI and to highlight individual risk factors for developing hepatotoxicity. Polymorphisms of bioactivation/ toxification pathways through CYP450 enzymes (Phase I), detoxification reactions (Phase II) and excretion/transport (Phase III) are explored together with immunological factors that might determine DILI. The importance of establishing a multidisciplinary and multi-centric network to promote the understanding and research in hepatotoxicity is underlined. Challenges such as genetic analyses for association studies and whole genome studies, pharmacogenetic testing and future approaches to study DILI are considered. Knowledge regarding these operational mechanisms could provide further insight for the prospective identification of susceptible patients at risk of developing drug-induced hepatotoxicity.

    Effect of Hysteresis on Measurements of Thin-Film Cell Performance

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    Transient or hysteresis effects in polycrystalline thin film CdS/CdTe cells are a function of pre-measurement voltage bias and whether Cu is introduced as an intentional dopant during back contact fabrication. When Cu is added, the current-density (J) vs. voltage (V) measurements performed in a reverse-to-forward voltage direction will yield higher open-circuit voltage (Voc), up to 10 mV, and smaller short-circuit current density (Jsc), by up to 2 mA/cm2, relative to scanning voltage in a forward-to-reverse direction. The variation at the maximum power point, Pmax, is however small. The resulting variation in FF can be as large as 3%. When Cu is not added, hysteresis in both Voc and Jsc is negligible however Pmax hysteresis is considerably greater. This behavior corroborates observed changes in depletion width, Wd, derived from capacitance (C) vs. voltage (V) scans. Measured values of Wd are always smaller in reverse-to-forward voltage scans, and conversely, larger in the forward-to-reverse voltage direction. Transient ion drift (TID) measurements performed on Cu-containing cells do not show ionic behavior suggesting that capacitance transients are more likely due to electronic capture-emission processes. J-V curve simulation using Pspice shows that increased transient capacitance during light-soak stress at 100 ºC correlates with increased space-charge recombination. Voltage-dependent collection however was not observed to increase with stress in these cells
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