476 research outputs found
TRANSPORT PROCESSES IN THE PLASMA EDGE
Eight samples of different varieties of commercial ice-creams sold in Spain were analysed for their fatty acid composition, with relevance on their trans-fatty acid profile. Saturated fatty acids occurred in the largest proportions in all samples (mean=68,1%), followed by monounsaturated (mean=21,1%) and polyunsaturated fatty acids (mean=5,2%). Trans fatty acids were detected in all samples ranging from 0,5%-19%, mean value 5,7%. Statistical analysis (cluster analysis) based on their fatty acid profile (saturated, monounsaturated and polyunsaturated and trans fatty acids) showed three groups of samples, depending on the main source of fat employed.Ocho muestras de distintas variedades de helados comercializados en España han sido analizadas para determinar su contenido en ácidos grasos de cadena media y larga, con especial interés en el contenido en ácidos grasos trans. La fracción mayoritaria en todos los casos, está constituida por los ácidos grasos saturados, que presentan un valor medio del 68,1%, seguido de la fracción de monoinsaturados (media=21,1%) y poliinsaturados (media=5,1%). El contenido en ácidos grasos trans, detectado en todas las muestras, oscila entre 0,5%-19%, con un valor medio de 5,7%. El análisis estadístico (análisis cluster) realizado, basándonos en el contenido en ácidos grasos saturados, monoinsaturados, poliinsaturados y trans, ha permitido diferenciar tres grupos distintos de helados según la fuente de grasa mayoritaria empleada en su elaboración
Obesidad en la infancia y en la adolescencia
La obesidad se considera en la actualidad un problema
de salud pública mundial debido al constante aumento
de su prevalencia asociado a los cambios en los estilos
de vida de la población, que incluyen la inactividad
física y el incremento en el ingreso de calorías.
Además, existe una baja percepción del problema por
parte de las familias, sobre todo de aquellas que tienen
más riesgo. La prevalencia actual en nuestro país se
estima en un 14%. Determinados sujetos pueden
tener una mayor predisposición genética a aumentar
de peso, y los genes pueden no expresarse totalmente
hasta la etapa adulta. En este artículo, se abordarán: la
etiopatogenia y su clasifi cación, la elevada comorbilidad
asociada, así como el abordaje diagnóstico y
terapéutico. La base fundamental del tratamiento es
la instauración de un programa multidisciplinar a largo
plazo que asocie educación nutricional, aumento de la
actividad física, restricción dietética y modifi caciones
de la conducta de la población. Se debe iniciar la
prevención en edades precoces; ya que, los hábitos de
salud se establecen en la infancia y, posteriormente,
será muy difícil modifi carlos. El pediatra tiene un gran
protagonismo detectando los factores y poblaciones de
riesgo, ejerciendo una acción educadora a nivel de las
familias, sus hijos, la escuela y los ámbitos sociales y
políticos.Obesity is now considered a global public health
problem due to the constant increase in its prevalence
associated with changes in the population’s lifestyles,
including the reduction in physical inactivity and an
increase in caloric intake. There is also a low awareness
of the problem in families, especially those at higher
risk. The current prevalence in Spain is estimated at
14%. Certain individuals may have a greater genetic
predisposition to gain weight, and genes may not be
fully expressed until adulthood. This article addresses:
pathogenesis and its classifi cation, high comorbidity
associated with obesity and its diagnostic and
therapeutic approach. The basis of the treatment is to
establish a multidisciplinary program that combines a
long-term nutritional education, an increase in physical
activity, a dietary restriction and certain behavioral
modifi cations in the population. Prevention should
be initiated at earlier ages, since health habits are
established during childhood and are very complicated
to change afterwards. Pediatricians play a major role
in detecting factors and segments of the population
at risk, ensuring the education in families, their
children and in schools and other social and political
environments
Revisión de los niveles de acidos grasos trans encontrados en distintos tipos de alimentos
In this paper a comprehensive review of trans-fatty acid levels reported in different types of food products is offered. The lowest levels are found in some types of bread (0,1%) while the highest levels (up to 40%) are found in fried potatoes. Some foods like shortenings, cakes and pastries may have up to 30% of these fatty acids. In milk and dairy products the reported levels are between 1.50% and 5.20%, in meat and derived products between 0.20% and 21,30%; in chocolates from 0% to 15, 70%. The greatest variability is found in margarines, where a variety has been reported from “trans-free products” to products containing up to 34. 30%. In relation to the trans-fatty acid profile, 18:1t is the most abundant fatty acid found in the majority of foods, followed by C18:2t, C18:3t, C18:1t y C14:1t. Due to the negative health effects of these fatty acids, there is a trend to reduce their levels in food products and to include them in the nutritional label of food packaging.En este trabajo se realiza una exhaustiva revisión bibliográfica de los contenidos en grasos trans en alimentos de distinto origen. Los niveles más bajos se encuentran en algunos tipos de pan (0,10%), y los más elevados (hasta 40%), en algunas muestras de patatas fritas. Alimentos tales como shortenings, algunos tipos de galletas y bollería contienen hasta el 30% de dichos ácidos grasos. En las leches y derivados se encuentran cantidades entre 1,50% y 5,20%; en carnes y derivados entre 0,20% y 21,30%; en chocolates desde cantidades nulas hasta 15,70%. La mayor variabilidad se registra en margarinas, entre las que se encuentran desde las “libres de trans”, hasta algunas con 34,30% de estos ácidos grasos. En cuanto a los distintos isómeros, el mayoritario es el C18:1t seguido del C18:2t, C18:3t, C18:1t y C14:1t. Debido a los efectos desfavorables que presentan sobre la salud se observa en los últimos años una tendencia a reducir este tipo de ácidos grasos en algunos alimentos y a incluirlos en el etiquetado nutricional de los alimentos
Phenylboronic Acids Probing Molecular Recognition against Class A and Class C beta-Lactamases
Worldwide dissemination of pathogens resistant to almost all available antibiotics represent a real problem preventing efficient treatment of infectious diseases. Among antimicrobial used in therapy, \u392-lactam antibiotics represent 40% thus playing a crucial role in the management of infections treatment. We report a small series of phenylboronic acids derivatives (BAs) active against class A carbapenemases KPC-2 and GES-5, and class C cephalosporinases AmpC. The inhibitory profile of our BAs against class A and C was investigated by means of molecular docking, enzyme kinetics and X-ray crystallography. We were interested in the mechanism of recognition among class A and class C to direct the design of broad serine \u392-Lactamases (SBLs) inhibitors. Molecular modeling calculations vs GES-5 and crystallographic studies vs AmpC reasoned, respectively, the ortho derivative 2 and the meta derivative 3 binding affinity. The ability of our BAs to protect \u392-lactams from BLs hydrolysis was determined in biological assays conducted against clinical strains: Fractional inhibitory concentration index (FICI) tests confirmed their ability to be synergic with \u392-lactams thus restoring susceptibility to meropenem. Considering the obtained results and the lack of cytotoxicity, our derivatives represent validated probe for the design of SBLs inhibitors
MHz Unidirectional Rotation of Molecular Rotary Motors
A combination of cryogenic UV-vis and CD spectroscopy and transient absorption spectroscopy at ambient temperature is used to study a new class of unidirectional rotary molecular motors. Stabilization of unstable intermediates is achieved below 95 K in propane solution for the structure with the fastest rotation rate, and below this temperature measurements on the rate limiting step in the rotation cycle can be performed to obtain activation parameters. The results are compared to measurements at ambient temperature using transient absorption spectroscopy, which show that behavior of these motors is similar over the full temperature range investigated, thereby allowing a maximum rotation rate of 3 MHz at room temperature under suitable irradiation conditions
Field-driven femtosecond magnetization dynamics induced by ultrastrong coupling to THz transients
Controlling ultrafast magnetization dynamics by a femtosecond laser is
attracting interest both in fundamental science and industry because of the
potential to achieve magnetic domain switching at ever advanced speed. Here we
report experiments illustrating the ultrastrong and fully coherent light-matter
coupling of a high-field single-cycle THz transient to the magnetization vector
in a ferromagnetic thin film. We could visualize magnetization dynamics which
occur on a timescale of the THz laser cycle and two orders of magnitude faster
than the natural precession response of electrons to an external magnetic
field, given by the Larmor frequency. We show that for one particular
scattering geometry the strong coherent optical coupling can be described
within the framework of a renormalized Landau Lifshitz equation. In addition to
fundamentally new insights to ultrafast magnetization dynamics the coherent
interaction allows for retrieving the complex time-frequency magnetic
properties and points out new opportunities in data storage technology towards
significantly higher storage speed.Comment: 25 page
Tbr1 Misexpression Alters Neuronal Development in the Cerebral Cortex
Changes in the transcription factor (TF) expression are critical for brain development, and they may also underlie neurodevelopmental disorders. Indeed, T-box brain1 (Tbr1) is a TF crucial for the formation of neocortical layer VI, and mutations and microdeletions in that gene are associated with malformations in the human cerebral cortex, alterations that accompany autism spectrum disorder (ASD). Interestingly, Tbr1 upregulation has also been related to the occurrence of ASD-like symptoms, although limited studies have addressed the effect of increased Tbr1 levels during neocortical development. Here, we analysed the impact of Tbr1 misexpression in mouse neural progenitor cells (NPCs) at embryonic day 14.5 (E14.5), when they mainly generate neuronal layers II-IV. By E18.5, cells accumulated in the intermediate zone and in the deep cortical layers, whereas they became less abundant in the upper cortical layers. In accordance with this, the proportion of Sox5+ cells in layers V-VI increased, while that of Cux1+ cells in layers II-IV decreased. On postnatal day 7, fewer defects in migration were evident, although a higher proportion of Sox5+ cells were seen in the upper and deep layers. The abnormal neuronal migration could be partially due to the altered multipolar-bipolar neuron morphologies induced by Tbr1 misexpression, which also reduced dendrite growth and branching, and disrupted the corpus callosum. Our results indicate that Tbr1 misexpression in cortical NPCs delays or disrupts neuronal migration, neuronal specification, dendrite development and the formation of the callosal tract. Hence, genetic changes that provoke ectopic Tbr1 upregulation during development could provoke cortical brain malformations
Time Estimation Predicts Mathematical Intelligence
Background: Performing mental subtractions affects time (duration) estimates, and making time estimates disrupts mental subtractions. This interaction has been attributed to the concurrent involvement of time estimation and arithmetic with general intelligence and working memory. Given the extant evidence of a relationship between time and number, here we test the stronger hypothesis that time estimation correlates specifically with mathematical intelligence, and not with general intelligence or working-memory capacity.
Methodology/Principal Findings: Participants performed a (prospective) time estimation experiment, completed several subtests of the WAIS intelligence test, and self-rated their mathematical skill. For five different durations, we found that time estimation correlated with both arithmetic ability and self-rated mathematical skill. Controlling for non-mathematical intelligence (including working memory capacity) did not change the results. Conversely, correlations between time estimation and non-mathematical intelligence either were nonsignificant, or disappeared after controlling for mathematical intelligence.
Conclusions/Significance: We conclude that time estimation specifically predicts mathematical intelligence. On the basis of the relevant literature, we furthermore conclude that the relationship between time estimation and mathematical intelligence is likely due to a common reliance on spatial ability
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