Aza-annulation of enaminones with crotonyl chloride - Formal reversal of regioselectivity.

The regiochemistry of aza-annulation of enaminones with alpha,beta-unsaturated acid chlorides bearing hydrogen atoms on the gamma-carbon is reversed when triethylamine is used as mediator. When the reaction was carried out at lower temperatures as 3-acyl beta,gamma-unsaturated compound could be isolated which cyclised to the desired product under thermal or basic conditions. The nature of this intermediate strongly suggests that a vinyl ketene is the active acylating agent. (C) 1997 Elsevier Science Ltd.

Using dispersive delay lines and time reversal for low contrast tumour detection

On the basis of the technique of time reversal (TR), through adding dispersive delay lines to each element of a TR mirror, a method for low contrast tumour detection is proposed. When compared with a conventional detection method, the proposed method improves refocusing onto a low dielectric contrast tumour. The method does not require an accurate estimate of the position of the tumour. The theoretical basis for the approach is given and numerical simulated results demonstrate the capability of the proposed method.

MRZ-99030 – a novel modulator of Aβ aggregation: II – reversal of Aβ oligomer-induced deficits in long-term potentiation (LTP) and cognitive performance in rats and mice.

β-amyloid1-42 (Aβ1-42) is a major endogenous pathogen underlying the aetiology of Alzheimer's disease (AD). Recent evidence indicates that soluble Aβ oligomers, rather than plaques, are the major cause of synaptic dysfunction and neurodegeneration. Small molecules that suppress Aβ aggregation, reduce oligomer stability or promote off-pathway non-toxic oligomerization represent a promising alternative strategy for neuroprotection in AD. MRZ-99030 was recently identified as a dipeptide that modulates Aβ1-42 aggregation by triggering a non-amyloidogenic aggregation pathway, thereby reducing the amount of intermediate toxic soluble oligomeric Aβ species. The present study evaluated the relevance of these promising results with MRZ-99030 under pathophysiological conditions i.e. against the synaptotoxic effects of Aβ oligomers on hippocampal long term potentiation (LTP) and two different memory tasks. Aβ1-42 interferes with the glutamatergic system and with neuronal Ca2+ signalling and abolishes the induction of LTP. Here we demonstrate that MRZ-99030 (100–500 nM) at a 10:1 stoichiometric excess to Aβ clearly reversed the synaptotoxic effects of Aβ1-42 oligomers on CA1-LTP in murine hippocampal slices. Co-application of MRZ-99030 also prevented the two-fold increase in resting Ca2+ levels in pyramidal neuron dendrites and spines triggered by Aβ1-42 oligomers. In anaesthetized rats, pre-administration of MRZ-99030 (50 mg/kg s.c.) protected against deficits in hippocampal LTP following i.c.v. injection of oligomeric Aβ1-42. Furthermore, similar treatment significantly ameliorated cognitive deficits in an object recognition task and under an alternating lever cyclic ratio schedule after the i.c.v. application of Aβ1-42 and 7PA2 conditioned medium, respectively. Altogether, these results demonstrate the potential therapeutic benefit of MRZ-99030 in AD.

Reversal in gender valuations of cataract surgery after the implementation of free screening and low-priced high-quality surgery in a rural population of southern China.

PURPOSE: To assess the impact of community outreach and the availability of low-cost surgeries [500 Renminbi (RMB) or 65 United States dollars (US$) per surgery] on the willingness to pay for cataract surgery among male and female rural-dwelling Chinese.METHODS: Cross-sectional willingness-to-pay surveys were conducted at the initiation of a cataract outreach programme in June 2001 and then again in July 2006. Respondents underwent visual acuity testing and provided socio-demographic data.RESULTS: In 2001 and 2006, 325 and 303 subjects, respectively, were interviewed. On average the 2006 sample subjects were of similar age, more likely to be female (p < 0.01), illiterate (p < 0.01), and less likely to come from a household with annual income of less than US$789 (62% vs. 87%, p < 0.01). Familiarity with cataract surgery increased from 21.2% to 44.4% over the 5 years for male subjects (p < 0.01) and 15.8%-44.4% among females (p < 0.01). The proportion of respondents willing to pay at least 500 RMB for surgery increased from 67% to 88% (p < 0.01) among male subjects and from 50% to 91% (p < 0.01) among females.CONCLUSIONS: Five years of access to free cataract testing and low-cost surgery programmes appears to have improved the familiarity with cataract surgery and increased the willingness to pay at least 500 RMB (US$65) for it in this rural population. Elderly women are now as likely as men to be willing to pay at least 500 RMB, reversing gender differences present 5 years ago.

An Empirical Evaluation of the Reversal Theory State Measure: Tracking Changes in the Experience of Video Commercials of Three Leading Running Brands

Abstract of paper delivered at the 17th International Reversal Theory Conference, Day 3, session 4, 01.07.15

An Empirical Evaluation of the Reversal Theory State Measure Using Three Running Brand Video Commercials

This paper reports on the first known empirical use of the Reversal Theory State Measure (RTSM) since its publication by Desselles et al. (2014). The RTSM was employed to track responses to three purposely-selected video commercials in a between-subjects design. Results of the study provide empirical support for the central conceptual premise of reversal theory, the experience of metamotivational reversals and the ability of the RTSM to capture them. The RTSM was also found to be psychometrically sound after adjustments were made to two of its three component subscales. Detailed account and rationale is provided for the analytical process of assessing the psychometric robustness of the RTSM, with a number of techniques and interpretations relating to component structure and reliability discussed. Agreeability and critique of the two available versions of the RTSM – the bundled and the branched – is also examined. Researchers are encouraged to assist development of the RTSM through further use, taking into account the analysis and recommendations presented.

Temperature-induced sex reversal is not responsible for sex-ratio distortions in grayling Thymallus thymallus or brown trout Salmo trutta.

On the basis of the experiments carried out over various years, it was concluded that (1) grayling Thymallus thymallus and brown trout Salmo trutta are resistant to temperature-induced sex reversal at ecologically relevant temperatures, (2) environmental sex reversal is unlikely to cause the persistent sex ratio distortion observed in at least one of the study populations and (3) sex-specific tolerance of temperature-related stress may be the cause of distorted sex ratios in populations of T. thymallus or S. trutta.

Thermal transport, photoconduction and electrical switching in selected chalcogenide glasses exhibiting carrier type reversal

Department of Instrumentation, Cochin University of Science and Technology

Pulsed-field studies of the magnetization reversal in molecular nanomagnets

We report experimental studies of crystals of Mn12 molecular magnetic clusters in pulsed magnetic fields with sweep rates up to 410^3 T/s . The steps in the magnetization curve are observed at fields that are shifted with respect to the resonant field values. The shift systematically increases as the rate of the field sweep goes up. These data are consistent with the theory of the collective dipolar relaxation in molecular magnets.

Generalization over contrast and mirror reversal, but not figure-ground reversal, in an "edge-based

Baylis & Driver (Nature Neuroscience, 2001) have recently presented data on the response of neurons in macaque inferotemporal cortex (IT) to various stimulus transformations. They report that neurons can generalize over contrast and mirror reversal, but not over figure-ground reversal. This finding is taken to demonstrate that ``the selectivity of IT neurons is not determined simply by the distinctive contours in a display, contrary to simple edge-based models of shape recognition'', citing our recently presented model of object recognition in cortex (Riesenhuber & Poggio, Nature Neuroscience, 1999). In this memo, I show that the main effects of the experiment can be obtained by performing the appropriate simulations in our simple feedforward model. This suggests for IT cell tuning that the possible contributions of explicit edge assignment processes postulated in (Baylis & Driver, 2001) might be smaller than expected.

Estudio sobre indicadores de validez del Reversal Test.

Comprobar la siguiente hipótesis: si ciertamente el Reversal es un test de madurez, sus resultados pueden constituir un índice predictivo del rendimiento en otras áreas. 740 alumnos de primero de EGB de centros de la región asturiana a través de un procedimiento aleatorio por conjuntos. La población se estratificó según: sexo, hábitat, régimen de enseñanza y asistencia o no de los alumnos a centros preescolares en el curso anterior. Para comprobar la hipótesis planteada, se relacionan los datos obtenidos en este test con los resultados de aquellos otros indicadores del rendimiento de los alumnos de primero de EGB: evaluación o exploración inicial de los alumnos efectuada por el docente al comenzar primero de EGB, los resultados del test de aptitudes cognoscitivas primaria I, y finalmente, la evaluación final al terminar el nivel de primero. Cuestionario 'ad hoc' con respuestas cerradas en escala y paramétrica, destinado a los docentes. Reversal y Test de aptitudes cognoscitivas primaria I. Calificación final en el área de Matemáticas, Lenguaje y global y calificaciones obtenidas por los alumnos en dos pruebas objetivas (Lenguaje y Matemáticas) expresamente preparadas con este fin. Análisis de las relaciones entre el reversal y las puntuaciones obtenidas en los demás indicadores. Cálculo de la validez de este test como instrumento predictivo a través de sus correlaciones con los demás indicadores utilizados.. Diferencias en función del nivel de maduración y el sexo: los alumnos clasificados con bajo nivel de maduración por el Reversal, obtienen las puntuaciones inferiores en todas las variables utilizadas; superioridad de las niñas respecto a los niños, aunque las diferencias no llegan a ser significativas. Interacción de variables en función del grado de madurez y el sexo: las correlaciones más elevadas se dan entre los índices de rendimiento y la madurez cognoscitiva evaluada por los docentes al comenzar el curso; se obtienen coeficientes diferentes con los diversos grupos entre rendimiento y test de aptitudes cognoscitivas, en los índices entre personalización y rendimiento se refleja claramente la influencia del nivel de maduración y el sexo. Relaciones entre el reversal y otros indicadores del rendimiento en función de la preescolarización: las correlaciones más altas se dan entre el Reversal y el Test de inteligencia primaria I; respecto al rendimiento de fin de curso los índices también son claramente representativos; los índices tienden a ser más bajos y desiguales en las relaciones entre el Reversal y la madurez cognoscitiva inicial evaluada por los docentes. Gran utilidad del Reversal como instrumento de diagnóstico y predicción. Se recomienda su utilización en los docentes por su facilidad de aplicación, valoración e interpretación. Este test permite obtener una información sobre el nivel de maduración del niño y 'pistas' de posibles anomalías o retrasos en las áreas perceptiva, espacial, etc..

El Reversal Test y la Ficha de Observaci??n de G. Yoakam en la determinaci??n de la madurez para la lectura

Resumen tomado de la publicaci??n

La madurez lectográfica y los tests ABC-Reversal, profilaxis de la dislexia.

Conocer el momento en el que el niño alcanza la madurez necesaria para comenzar el aprendizaje de la lectura, ya que parte de los fracasos y retrasos en el aprendizaje de la lectura vienen dados por la inadecuación de este aprendizaje y el momento madurativo del niño.. La muestra ha constado de 120 niños de Educación Preescolar de dos Colegios, uno nacional y el otro privado.. Experimental.. Para realizar este estudio se han empleado dos tipos de tests: El ABC y Reversal. . Experimental, en la que se ha llevado a cabo un estudio estadístico, hallando las puntuaciones típicas, puntuaciones directas, estudio de las medias y por último las correlaciones entre ambos tests. . Las conclusiones a las que se ha llegado con este estudio son las siguientes: Para afrontar el aprendizaje de la lectura se necesita una edad determinada, llamada de madurez lectora que es específica de cada niño ya que no existe una relación entre la edad de madurez lectora y la edad cronológica. Desde otro punto de vista, una inteligencia alta o normal unida al fracaso en el reversal Test y a algunas pruebas del test ABC, indica existencia de trastornos relacionados con la estructuración espacial y la capacidad perceptiva. A su vez, la madurez para la lectura puede favorecerse y adelantarse, incluso, mediante el desarrollo adecuado de los factores fisiológicos, psicológicos y socio-ambientales que están implicados en el aprendizaje de la lectoescritura. Los trastornos lectores llamados dislexias pueden prevenirse si se respetan los niveles de madurez de cada niño y si se desarrollan normalmente los factores que pueden originarlas..

Evidence for a reversal with age in the pattern of near-wall blood flow around aortic branches

The changes that occur with age in the distribution of atherosclerotic lesions around arterial branch points challenge accepted theories relating disease to haemodynamic stresses. We investigated whether flow near branch points changes with age in a way that can account for the different lesion distributions. Flow around 20 branches from immature and mature aortas was investigated by examining the length:width ratio and orientation of endothelial nuclei; these properties depend on the magnitude and direction of near-wall flows, respectively. There were significant changes in the pattern of nuclear shape with age, consistent with a reversal in the pattern of shear around branches. In control regions away from branches, there were no such changes. The role of haemodynamic stresses in atherogenesis may require re-evaluation in the light of these results. (C) 2003 Elsevier Ireland Ltd. All rights reserved.