Transcultural adaptation and reliability of the spanish version of a questionnaire of oral hygiene advice given by dentists in Chile

Aim: To adapt and evaluate validity-reliability the spanish version of the questionnaire for oral hygiene advice given by dentist in Chile. Materials and methods: Validation study conducted according COSMIN recommendations. The original questionnaire in english was adapted to spanish by translation, back translation, expert review and pilot test sample of 56 dentists. The instrument consisted of 3 sections: recommendations for oral hygiene, relevance given to the delivery of oral hygiene instruction and training and experience in delivering oral hygiene recommendations. It was reapplied in 5 of them a week later. Reliability was measured by internal consistency (Cronbach's alpha), test-retest (Cohen's kappa and weighted kappa) and measurement error (limits of agreement, LdA). Content validity was evaluated by experts and construct validity through convergent validity (Pearson correlation). Results: A good level of internal consistency that applies to 5 items (Cronbach's alpha = 0.73) was obtained. For items of nominal scale the Cohen kappa coefficient was 0.80 (95% CI = 0.64 to 0.95) and for ordinal items weighted kappa coefficient (linear weighting) was 0.76 (95% CI = 0.65 to 0.88). The difference between the scores calculated for the measurements was 1 standard deviation 2.35. 95% of the differences were between -5.7 to 3.7 (+/- 4.7 LdA = 1) and the variance of the total score was 29 to 41. A good level of convergent validity (Pearson correlation = 0.63) was obtained. Conclusion: The final questionnaire obtained is valid and reliable for use in chilean dentists with a profile like those included in this study to identify and quantify the oral hygiene instruction they provide to patients. Future studies should assess the validity and reliability of this adaptation other spanish-speaking countries.publishersversionPeer reviewe

Topological Dirac states in asymmetric Pb1-xSnxTe quantum wells

The electronic structure of lead-salt (IV-VI semiconductor) topological quantum wells (T-QWs) is investigated with analytical solutions of the effective 4x4 Dimmock k & BULL; p model, which gives an accurate description of the bands around the fundamental energy gap. Specific results for three-layer Pb1-xSnxTe nanostructures with varying Sn composition are presented and the main differences between topological and normal (N) QWs highlighted. A series of new features are found in the spectrum of T-QWs, in particular in asymmetric QWs where large (Rashba spin-orbit) splittings are obtained for the topological Dirac states inside the gap

Electron g factor anisotropy in asymmetric III-V semiconductor quantum wells

The electron effective g factor tensor in asymmetric III-V semiconductor quantum wells (AQWs) and its tuning with the structure parameters and composition are investigated with envelope-function theory and the 8 x 8k . p Kane model. The spin-dependent terms in the electron effective Hamiltonian in the presence of an external magnetic field are treated as a perturbation and the g factors g(perpendicular to)* and g(parallel to)*, for the magnetic field in the QW plane and along the growth direction, are obtained analytically as a function of the well width L. The effects of the structure inversion asymmetry (SIA) on the electron g factor are analyzed. For the g-factor main anisotropy Delta g = g(perpendicular to)*-g(parallel to)*. in AQWs, a sign change is predicted in the narrow well limit due to SIA, which can explain recent measurements and be useful in spintronic applications. Specific results for narrow-gap AlSb/InAs/GaSb and AlxGa1-xAsGaAs/AlyGa1-yAs AQWs are presented and discussed with the available experimental data; in particular InAs QWs are shown to not only present much larger g factors but also a larger g-factor anisotropy, and with the opposite sign with respect to GaAs QWs

Expresión de ICAM-1 en el Endotelio de Arterias Humanas Mediante Inmunohistoquímica

Moore-Carrasco, R (reprint author), Univ Talca, Fac Ciencias Salud, Dept Bioquim Clin & Inmunohematol, Programa Invest Factores Riesgo Enfermedades Card, POB 747, Talca, Chile.Cardiovascular diseases (CVD) are the leading cause of death in the world. Among them the ischemic type are of great importance. where the development of atherosclerotic plaques is the central pathophysiological process. The study of atherosclerosis is critical to understand how this disease process begins and factors influencing its development. Various laboratory methods, including immunohistochemistry, allow the recognition of cells and molecules involved in the atheromatous process that are interacting according to the progression of the lesion. A marker of endothelial dysfunction is the increased expression of intercellular adhesion molecule ICAM-1. In this paper, an immunohistochemistry method was standardized for the adhesion molecule ICAM-1, and its expression was studied in healthy human arteries with atheromatous plaque. In samples of human arteries with atherosclerotic disease, the expression of ICAM-1 was observed lobe increased, but was hardly recognizable. This mainly because the tissue used as a control for standardization was a tonsil with an inflammatory process and hyperplasia, which significantly increases the expression of ICAM-1. The implementation of the immunohistochemistry method for ICAM-1 in human arteries will reveal endothelial dysfunction states that will enable a future design and implementation of methods of diagnosis in atherosclerotic processes in the early stages

Calibration of the mixing-length theory for structures of helium-dominated atmosphere white dwarfs

We perform a calibration of the mixing-length parameter at the bottom boundary of the convection zone for helium-dominated atmospheres of white dwarfs. This calibration is based on a grid of 3D DB (pure-helium) and DBA (helium-dominated with traces of hydrogen) model atmospheres computed with the co5bold radiation-hydrodynamics code, and a grid of 1D DB and DBA envelope structures. The 3D models span a parameter space of hydrogen-to-helium abundances in the range −10.0 ≤ log (H/He) ≤−2.0, surface gravities in the range 7.5 ≤ log g ≤ 9.0, and effective temperatures in the range 12 000 K ≲ Teff ≲ 34 000 K. The 1D envelopes cover a similar atmospheric parameter range, but are also calculated with different values of the mixing-length parameter, namely 0.4 ≤ ML2/α ≤ 1.4. The calibration is performed based on two definitions of the bottom boundary of the convection zone: the Schwarzschild and the zero convective flux boundaries. Thus, our calibration is relevant for applications involving the bulk properties of the convection zone including its total mass, which excludes the spectroscopic technique. Overall, the calibrated ML2/α is smaller than what is commonly used in evolutionary models and theoretical determinations of the blue edge of the instability strip for pulsating DB and DBA stars. With calibrated ML2/α we are able to deduce more accurate convection zone sizes needed for studies of planetary debris mixing and dredge-up of carbon from the core. We highlight this by calculating examples of metal-rich 3D DBAZ models and finding their convection zone masses. Mixing-length calibration represents the first step of in-depth investigations of convective overshoot in white dwarfs with helium-dominated atmospheres

Heavily n-doped Ge : low-temperature magnetoresistance properties on the metallic side of the metal–nonmetal transition

We report here an experimental and theoretical study on the magnetoresistance properties of heavily phosphorous doped germanium on the metallic side of the metal–nonmetal transition. An anomalous regime, formed by negative values of the magnetoresistance, was observed by performing low-temperature measurements and explained within the generalized Drude model, due to the many-body effects. It reveals a key mechanism behind the magnetoresistance properties at low temperatures and, therefore, constitutes a path to its manipulation in such materials of great interest in fundamental physics and technological applications

Aging in a Two-Dimensional Ising Model with Dipolar Interactions

Aging in a two-dimensional Ising spin model with both ferromagnetic exchange and antiferromagnetic dipolar interactions is established and investigated via Monte Carlo simulations. The behaviour of the autocorrelation function $C(t,t_w)$ is analyzed for different values of the temperature, the waiting time $t_w$ and the quotient $\delta=J_0/J_d$, $J_0$ and $J_d$ being the strength of exchange and dipolar interactions respectively. Different behaviours are encountered for $C(t,t_w)$ at low temperatures as $\delta$ is varied. Our results show that, depending on the value of $\delta$, the dynamics of this non-disordered model is consistent either with a slow domain dynamics characteristic of ferromagnets or with an activated scenario, like that proposed for spin glasses.Comment: 4 pages, RevTex, 5 postscript figures; acknowledgment added and some grammatical corrections in caption

Pre-concentration of rosuvastatin using solid-phase extraction in a molecularly imprinted polymer and analytical application in water supply

In this work, it is shown the development and validation of innovative analytical methodology based on solid-phase extraction (SPE) with molecularly imprinted polymers (MIP) as a sorbent associated to UV–Vis spectroscopy to isolate and quantify, respectively, rosuvastatin (RSV) in water samples. For this purpose, porogenic solvent in MIP synthesis and SPE extraction parameters for MIP and non-imprinted polymers (NIP) were evaluated univariately for comparison purposes. The sorptive capacity and characterization studies by infrared spectroscopy and atomic force microscopy showed difference between MIP and NIP. The selectivity study of the MIP–RSVagainst other statins (simvastatin and atorvastatin) showed that the synthesized MIP can also be applied as a solid phase for isolation and quantitative pre-concentration of RSVand atorvastatin. The conjugation of SPE and UV–Vis spectroscopy in the determination of RSV in aqueous matrices led to large factor of pre-concentration (125 times), limit of detection (LOD) of 3 μg L−1, limit of quantification (LOQ) of 10 μg L−1, precision of 2.87% (n = 10), and accuracy of 83.1% (n = 4)

PANDAS: un modelo autoinmune de trastorno cerebral

ResumenEn 1998, en el Instituto Nacional de Salud Mental de los Estados Unidos definió los criterios de diagnóstico para los trastornos neuropsiquiátricos asociados a infección por estreptococo beta hemolítico del grupo A (PANDA).[Cadena LP, Toloza CR, Rueda GE. PANDAS: un modelo autoinmune de trastorno cerebral. MedUNAB 2004;7:106-14].Palabras clave: PANDAS, estreptococo beta hemolítico del grupo A, trastorno obsesivo, trastorno de la tourette

Horizontal spreading of planetary debris accreted by white dwarfs

White dwarfs with metal-polluted atmospheres have been studied widely in the context of the accretion of rocky debris from evolved planetary systems. One open question is the geometry of accretion and how material arrives and mixes in the white dwarf surface layers. Using the three-dimensional (3D) radiation hydrodynamics code CO5BOLD, we present the first transport coefficients in degenerate star atmospheres that describe the advection–diffusion of a passive scalar across the surface plane. We couple newly derived horizontal diffusion coefficients with previously published vertical diffusion coefficients to provide theoretical constraints on surface spreading of metals in white dwarfs. Our grid of 3D simulations probes the vast majority of the parameter space of convective white dwarfs, with pure-hydrogen atmospheres in the effective temperature range of 6000–18 000 K and pure-helium atmospheres in the range of 12 000–34 000 K. Our results suggest that warm hydrogen-rich atmospheres (DA; ≳13000 K) and helium-rich atmospheres (DB and DBA; ≳30000 K) are unable to efficiently spread the accreted metals across their surface, regardless of the time dependence of accretion. This result may be at odds with the current non-detection of surface abundance variations in white dwarfs with debris discs. For cooler hydrogen- and helium-rich atmospheres, we predict a largely homogeneous distribution of metals across the surface within a vertical diffusion time-scale. This is typically less than 0.1 per cent of disc lifetime estimates, a quantity that is revisited in this paper using the overshoot results. These results have relevance for studies of the bulk composition of evolved planetary systems and models of accretion disc physics