Determinación de la higroscopicidad y comportamiento termodinámico de la madera juvenil y madura a través de sus isotermas de sorción

La respuesta higroscópica de la madera varía a lo largo de la dirección radial del árbol. El aumento de corta de ejemplares jóvenes y el uso de troncos de pequeños diámetros en la industria de los productos forestales, hacen preciso estudiar el comportamiento higroscópico tanto de la madera juvenil como de la madura. Su determinación proporciona información para comprender los mecanismos de sorción. Asimismo, la obtención de las propiedades termodinámicas de ambos tipos de madera facilita la modelización de procesos industriales como el secado o el encolado. En el presente trabajo, se ha comparado el comportamiento higroscópico y las propiedades termodinámicas de la madera juvenil y madura de Abies pinsapo Boissier, Abies alba Mill., Pinus canariensis C. Sm. ex DC., Pinus nigra Arnold, Pinus uncinata Mill. ex Mirb. y Pinus pinea L. Para este propósito se han utilizado las isotermas de sorción obtenidas mediante el método tradicional de sales saturadas descrito por COST Action E8 a 15, 35 y 50ºC en Abies pinsapo, Abies alba, Pinus nigra, Pinus uncinata y Pinus pinea, y a 35 y 50ºC en Pinus canariensis. Igualmente, se ha empleado el equipo dynamic vapor sorption (DVS) en la obtención de las isotermas de Pinus pinea a 35 y 50ºC. El ajuste de las curvas se ha realizado mediante el modelo Guggenheim, Anderson y de Boer-Dent (GAB), cumpliendo todas las muestras los criterios de aceptación establecidos. En el estudio de las isotermas se ha calculado el coeficiente y área de histéresis entre el proceso de adsorción y desorción para cada una de las muestras. Con el fin de comprender el comportamiento higroscópico experimentado por cada madera se ha determinado la composición química, espectros de infrarrojos (FTIR) y difractogramas de rayos X de cada una. Los parámetros termodinámicos - calor isostérico neto y total heat of wetting - se han obtenido a partir de las isotermas de sorción mediante el método de integración de la ecuación de Clausius-Clapeyron. Finalmente, se han comparado los datos obtenidos con el método tradicional de sales saturadas y con dynamic vapor sorption con el propósito de conocer la existencia de similitudes entre ambas metodologías. Los resultados mostraron que los puntos de equilibrio son, en la mayor parte de los casos, superiores en la madera madura frente a la juvenil, y por tanto las isotermas de la madera madura se encuentran siempre por encima de las de la juvenil, debido principalmente a la composición química. Respecto a las propiedades termodinámicas, se ha determinado que la energía involucrada en los procesos de sorción es superior en la madera madura que en la madera juvenil, siendo mayor en el proceso de desorción frente al de adsorción. En la comparación de las metodologías de sales saturadas y dynamic vapor sorption no se han detectado casi diferencias significativas en el proceso de adsorción, mientras que sí se han obtenido en el de desorción. ABSTRACT The hygroscopic response of wood varies throughout the radial direction of the tree. The longer cut of young trees and the use of small-diameter trunks in the forest product industry make it necessary to study the hygroscopic behaviour of both juvenile and mature wood. Determining this behaviour in both types of wood provides information for understanding the sorption mechanisms. Similarly, obtaining the thermodynamic properties of juvenile and mature wood facilitates modelling of industrial processes such as drying and bonding. In this study a comparison was made of the hygroscopic behaviour and thermodynamic properties of juvenile and mature wood of Abies pinsapo Boissier, Abies alba Mill., Pinus canariensis C. Sm. ex DC., Pinus nigra Arnold, Pinus uncinata Mill. ex Mirb. and Pinus pinea L. This was done by obtaining the sorption isotherms using the traditional saturated salt method described by COST Action E8 at 15, 35 and 50ºC in Abies pinsapo, Abies alba, Pinus nigra, Pinus uncinata and Pinus pinea, and at 35 and 50ºC in Pinus canariensis. In addition, dynamic vapour sorption (DVS) was used to obtain the isotherms of Pinus pinea at 35 and 50ºC. The curves were fitted using the Guggenheim, Anderson and de Boer- Dent (GAB) model and all samples met the established acceptance criteria. In the study of the isotherms, the hysteresis coefficient and area of the hysteresis loop between adsorption and desorption were calculated for each sample. To understand the hygroscopic behaviour of juvenile and mature wood, the chemical composition, infrared spectra (FTIR) and X-ray diffractograms of each type of wood were determined. The thermodynamic parameters - net isosteric heat and total heat of wetting - were obtained from the sorption isotherms by applying the integration method of the Clausius-Clapeyron equation. The data obtained using the traditional saturated salt method and with dynamic vapour sorption were compared to determine the similarities between the two methods. The results showed that the equilibrium points are greater in the mature wood than in the juvenile wood in most cases, and therefore the mature wood isotherms are always above the juvenile wood isotherms, mainly because of the chemical composition. As regards the thermodynamic properties, it was determined that the energy involved in the sorption processes is greater in the mature wood than in the juvenile wood, and is greater in the desorption process than in the adsorption process. On comparing the saturated salt and dynamic vapour sorption methods, almost no significant differences were detected in the adsorption process, but significant differences were obtained in the desorption process

Obtención del módulo de elasticidad estático de la madera de Pinus radiata D. Don. mediante la comparación de técnicas de regresión y una red neuronal artificial

El objetivo de este estudio ha sido comparar el método de regresión tradicional frente al diseño de una red neuronal artificial del tipo perceptrón multicapa para obtener el MOEestático de la madera de Pinus radiata D. Don. a partir del MOEdinámico obtenido por técnica de ultrasonidos en el primer caso y a partir de la velocidad de propagación de la onda de ultrasonidos en el segundo

Procesos reflexivos promovidos en las prácticas escolares de los alumnos de magisterio

The aim of that research fites the authors concern for the efficiency of practice period during student teaching experience. 195 student teaching participate in the investigation answering the questionnaire to determine their perception of the degree to which they were encouraged to use reflective thinking and teaching skills during their student teaching. Questions were clustered under 4 mayor categories of reflective teaching: 1) retrospective and predictive thought, 2) critical inquiry, 3) problem-solving skills, and 4) acceptance and use of feedback. The results show that student teachers perceived moderate encouragement for several items within the 4 clusters.El propósito de esta investigación responde a la preocupación de los autores por la eficacia del período de prácticas en las Escuelas de Magisterio. 195 estudiantes para profesor participan en la investigación respondiendo a un cuestionario para determinar sus percepciones acerca del grado en el que se han sentido estimulados a hacer uso de un pensamiento reflexivo durante su período de prácticas. Las cuestiones son agrupadas bajo 4 grandes categorías: 1) pensamiento retrospectivo y predictivo, 2) indagación crítica, 3) habilidades de resolución de problemas y 4) aceptación y uso del feed-back. Los resultados muestran que los estudiantes perciben que han recibido un estímulo moderado para la realización de los distintos ítems que corresponden a las 4 categorías

Constraints to virus infection in Nicotiana benthamiana plants transformed with a potyvirus amplicon

<p>Abstract</p> <p>Background</p> <p>Plant genomes have been transformed with full-length cDNA copies of viral genomes, giving rise to what has been called 'amplicon' systems, trying to combine the genetic stability of transgenic plants with the elevated replication rate of plant viruses. However, amplicons' performance has been very variable regardless of the virus on which they are based. This has boosted further interest in understanding the underlying mechanisms that cause this behavior differences, and in developing strategies to control amplicon expression.</p> <p>Results</p> <p><it>Nicotiana benthamiana </it>plants were transformed with an amplicon consisting of a full-length cDNA of the potyvirus <it>Plum pox virus </it>(PPV) genome modified to include a GFP reporter gene. Amplicon expression exhibited a great variability among different transgenic lines and even among different plants of the same line. Plants of the line 10.6 initially developed without signs of amplicon expression, but at different times some of them started to display sporadic infection foci in leaves approaching maturity. The infection progressed systemically, but at later times the infected plants recovered and returned to an amplicon-inactive state. The failure to detect virus-specific siRNAs in 10.6 plants before amplicon induction and after recovery suggested that a strong amplicon-specific RNA silencing is not established in these plants. However, the coexpression of extra viral silencing suppressors caused some amplicon activation, suggesting that a low level of RNA silencing could be contributing to maintain amplicon repression in the 10.6 plants. The resistance mechanisms that prevent amplicon-derived virus infection were also active against exogenous PPV introduced by mechanical inoculation or grafting, but did not affect other viruses. Amplicon-derived PPV was able to spread into wild type scions grafted in 10.6 rootstocks that did not display signs of amplicon expression, suggesting that resistance has little effect on virus movement.</p> <p>Conclusions</p> <p>Our results suggest that amplicon-derived virus infection is limited in this particular transgenic line by a combination of factors, including the presumed low efficiency of the conversion from the transgene transcript to replicable viral RNA, and also by the activation of RNA silencing and other defensive responses of the plant, which are not completely neutralized by viral suppressors.</p

Sponge-like molecular cage for purification of fullerenes

Since fullerenes are available in macroscopic quantities from fullerene soot, large efforts have been geared toward designing efficient strategies to obtain highly pure fullerenes, which can be subsequently applied in multiple research fields. Here we present a supramolecular nanocage synthesized by metal-directed self-assembly, which encapsulates fullerenes of different sizes. Direct experimental evidence is provided for the 1:1 encapsulation of C 60, C 70, C 76, C 78 and C 84, and solid state structures for the host-guest adducts with C 60 and C 70 have been obtained using X-ray synchrotron radiation. Furthermore, we design a washing-based strategy to exclusively extract pure C 60 from a solid sample of cage charged with a mixture of fullerenes. These results showcase an attractive methodology to selectively extract C 60 from fullerene mixtures, providing a platform to design tuned cages for selective extraction of higher fullerenes. The solid-phase fullerene encapsulation and liberation represent a twist in host-guest chemistry for molecular nanocage structures

Perfil de ingresos y urgencias pediátricas en período epidémico de rotavirus en Valladolid. Utilidad de un modelo predictivo

Producción CientíficaEste estudio pretende determinar las semanas de alta circulación de rotavirus en valladolid, y comparar las características de los ingresos y urgencias en período epidémico con respecto al período no epidémico. Se utilizaron las declaraciones al sistema de información microbiológica, el conjunto mínimo básico de datos y el registro de urgencias. Se calcularon los casos esperados para 2006 a partir de un modelo elaborado previamente. Si los casos observados superaban el umbral superior del 95% de los esperados, la semana se consideró epidémica. Se compararon las características de los ingresos y urgencias en ambos períodos. En 2006 se diagnosticaron un 42% menos de los casos esperados. La media de ingresos diarios fue superior en período epidémico (diferencia=1,49; p=0,01), y también fue mayor la duración media del ingreso. La actividad del servicio de pediatría se incrementó en período epidémico, por lo que es oportuna la implantación de actividades de vigilancia, programas de prevención y control frente a rotavirus en el ámbito hospitalario

Detection of mild cognitive impairment in people older than 65 years of age and its relationship to cardiovascular risk factors (DECRIVAM)

[ENG]Background: Studies centered on the detection of cognitive impairment and its relationship to cardiovascular risk factors in elderly people have gained special relevance in recent years. Knowledge of the cardiovascular risk factors that may be associated to cognitive impairment could be very useful for introducing treatments in early stagesthereby possibly contributing to improve patient quality of life. The present study explores cognitive performance in people over 65 years of age in Salamanca (Spain), with special emphasis on the identification of early symptoms of cognitive impairment, with the purpose of detecting mild cognitive impairment and of studying the relationships between this clinical situation and cardiovascular risk factors. Methods/Design: A longitudinal study is contemplated. The reference population will consist of 420 people over 65 years of age enrolled through randomized sampling stratified by healthcare area, and who previously participated in another study. Measurement: a) Sociodemographic variables; b) Cardiovascular risk factors; c) Comorbidity; d) Functional level for daily life activities; and e) Study of higher cognitive functions based on a neuropsychological battery especially adapted to the evaluation of elderly people. Discussion: We hope that this study will afford objective information on the representative prevalence of cognitive impairment in the population over 65 years of age in Salamanca. We also hope to obtain data on the relationship between cognitive impairment and cardiovascular risk factors in this specific population group. Based on the results obtained, we also will be able to establish the usefulness of some of the screening tests applied during the study, such as the Mini-Mental State Examination and the 7 Minute Screen test. Trial registration: ClinicalTrials.gov: NCT0132719

Supramolecular fullerene sponges as catalytic masks for regioselective functionalization of C60

Isomer-pure poly-functionalized fullerenes are required to boost the development of fullerene chemistry in all fields. On a general basis, multi-adduct mixtures with uncontrolled regioselectivity are obtained, and the use of chromatographic purification is prohibitively costly and time consuming, especially in the production of solar cells. Single-isomer poly-functionalized fullerenes are only accessible via stoichiometric, multistep paths entailing protecting-unprotecting sequences. Herein, a nanocapsule is used as a supramolecular tetragonal prismatic mask to exert full control on the reactivity and the equatorial regioselectivity of Bingel-Hirsch cyclopropanation reactions of a confined C guest. Thus, equatorial bis-, tris-, and tetrakis-C homo-adducts are exclusively obtained in a stepwise manner. Furthermore, isomer-pure equatorial hetero-tetrakis-adducts or hetero-Th-hexakis-adducts are synthesized at will in one-pot synthesis for the first time. This work provides a synthetically valuable path to produce a plethora of new pure-isomer poly-functionalized C-based compounds as candidates for testing in solar cell devices and biomedical applications

Combined use of smartphone and smartband technology in the improvement of lifestyles in the adult population over 65 years: study protocol for a randomized clinical trial (EVIDENT-Age study)

Background The increasing use of smartphones by older adults also increases their potential for improving different aspects of health in this population. Some studies have shown promising results in the improvement of cognitive performance through lifestyle modification. All this may have a broad impact on the quality of life and carrying out daily living activities. The objective of this study is to evaluate the effectiveness of combining the use of smartphone and smartband technology for 3 months with brief counseling on life habits, as opposed to providing counseling only, in increasing physical activity and improving adherence to the Mediterranean diet. Secondary objectives are to assess the effect of the intervention on body composition, quality of life, independence in daily living activities and cognitive performance. Methods This study is a two-arm cluster-randomized trial that will be carried out in urban health centers in Spain. We will recruit 160 people aged between 65 and 80 without cardiovascular disease or cognitive impairment (score in the Mini-mental State Examination ≥24). On a visit to their center, intervention group participants will be instructed to use a smartphone application for a period of 3 months. This application integrates information on physical activity received from a fitness bracelet and self-reported information on the patient’s daily nutritional composition. The primary outcome will be the change in the number of steps measured by accelerometer. Secondary variables will be adherence to the Mediterranean diet, sitting time, body composition, quality of life, independence in daily living activities and cognitive performance. All variables will be measured at baseline and on the assessment visit after 3 months. A telephone follow-up will be carried out at 6 months to collect self-reported data regarding physical activity and adherence to the Mediterranean diet. Discussion Preventive healthy aging programs should include health education with training in nutrition and lifestyles, while stressing the importance of and enhancing physical activity; the inclusion of new technologies can facilitate these goals. The EVIDENT-AGE study will incorporate a simple, accessible intervention with potential implementation in the care of older adults.This study was supported in part by grants funded by the Instituto de Salud Carlos III, Institute of Biomedical Research of Salamanca (IBSAL)-IBY17/00003, and the Spanish Research Network for Preventive Activities and Health Promotion in Primary Care (REDIAPP)-RD16/0007

Impact of subtrochanteric fractures in the geriatric population : better pre-fracture condition but poorer outcome than pertrochanteric fractures: evidence from the Spanish Hip Fracture Registry

Clinical management in orthogeriatric units and outcome indicators are similar for extracapsular fragility hip fractures, without discriminating between subtrochanteric and pertrochanteric fractures. Geriatric patients, 75 years or older, with subtrochanteric fractures have worse clinical and functional outcomes than those with pertrochanteric fractures. Retrospective observational study of data prospectively collected by the Spanish Hip Fracture Registry including patients 75 years or older, admitted for extracapsular hip fractures from January 2017 to June 2019. Demographic and baseline status, pre-operative, post-operative and 30-day follow-up data were included. A total of 13,939 patients with extracapsular hip fractures were registered: 12,199 (87.5%) pertrochanteric and 1740 (12.5%) subtrochanteric. At admission, patients with subtrochanteric fractures were younger (86.5 ± 5.8 versus 87.1 ± 5.6 years old), had better pre-fracture mobility (3.7 ± 2.7 versus 3.9 ± 2.8) (1-to-10 scale, 1 being independent) and were more likely to be living at home; those with pertrochanteric fractures had worse cognitive function (Pfeiffer 3.3 ± 3.3 versus 3.8 ± 3.5). The subtrochanteric fracture group showed worse post-fracture mobility (7.3 ± 2.7 versus 6.7 ± 2.7) and greater deterioration of mobility (3.7 ± 3.0 versus 2.9 ± 2.7). Among individuals living at home at baseline, those with subtrochanteric fractures were more likely to remain in an assisted facility at 30-day follow-up. In-hospital mortality during acute admission was higher for the subtrochanteric group (5.6% versus 4.5%) (p = 0.028). To our knowledge, this is the first paper highlighting the differences between these two fracture groups in the geriatric population. Subtrochanteric fractures in the older population are a different and worse entity, with greater morbimortality and functional decline than pertrochanteric fractures. Despite being younger and fitter at admission, older patients with subtrochanteric fractures have a higher risk of remaining non-weight bearing and undergoing re-operation and institutionalization. Orthogeriatric units should be aware of this and manage subtrochanteric fractures accordingly. Level of evidence: IV. The online version contains supplementary material available at 10.1186/s10195-022-00637-8