Modeling the heat transfer by conduction of nanocellular polymers with bimodal cellular structures

Nanocellular polymers are a new generation of materials with the potential of being used as very efficient thermal insulators. It has been proved experimentally that these materials present the Knudsen effect, which strongly reduces the conductivity of the gas phase. There are theoretical equations to predict the thermal conductivity due to this Knudsen effect, but all the models consider an average cell size. In this work, we propose a model to predict the thermal conductivity due to the conduction mechanisms of nanocellular materials with bimodal cellular structures, that is, with two populations of cells, micro and nanocellular. The novelty of our work is to consider not only the average cell size, but the cell size distribution. The predictions of the model are compared with the experimental conductivity of two real bimodal systems based on poly(methyl methacrylate) (PMMA), and it is proved that this new model provides more accurate estimations of the conductivity than the models that do not consider the bimodality. Furthermore, this model could be applied to monomodal nanocellular polymers. In particular, for monomodal materials presenting a wide cell size distribution and at low densities, the model predicts important variations in comparison with the current models in the literature. This result indicates that the cell size distribution must be included in the estimations of the thermal conductivity of nanocellular polymer

Functionalised graphene sheets as effective high dielectric constant fillers

A new functionalised graphene sheet (FGS) filled poly(dimethyl)siloxane insulator nanocomposite has been developed with high dielectric constant, making it well suited for applications in flexible electronics. The dielectric permittivity increased tenfold at 10 Hz and 2 wt.% FGS, while preserving low dielectric losses and good mechanical properties. The presence of functional groups on the graphene sheet surface improved the compatibility nanofiller/polymer at the interface, reducing the polarisation process. This study demonstrates that functionalised graphene sheets are ideal nanofillers for the development of new polymer composites with high dielectric constant values

Hypothalamic Networks in Adolescents With Excess Weight: Stress-Related Connectivity and Associations With Emotional Eating

Objective: Adolescents with excess weight are particularly sensitive to stress, which may contribute to the presence of emotional eating behaviors. It is proposed that this may be due to alterations in the connectivity between hypothalamic networks and regions of the "emotional nervous system," involved in the regulation of energy balance and stress processing. However, this remains to be clarified in adolescents with excess weight. Method: We investigated whole-brain differences in the functional connectivity of the medial and lateral hypothalamus (MH and LH) between adolescents with excess weight (EW, n = 53; mean age = 14.64 years, SD = 1.78) and normal weight (NW, n = 51; mean age = 15.29 years, SD = 1.75) using seed-based resting-state analyses. Then, in a subset of 22 adolescents with EW (mean age = 15.75 years, SD = 1.70) and 32 with NW (mean age = 15.27, SD = 2.03), we explored for group interactions between the MH/LH networks and stress response in the Trier Social Stress Task (TSST) and emotional eating, assessed with the Dutch Eating Behavior Questionnaire (DEB-Q). Results: Compared to NW, EW showed higher functional connectivity in the LH-orbitofrontal cortex, ventral striatum, anterior insula, and in the MH-middle temporal cortex networks. EW also showed lower connectivity in the LH-cerebellum, and in the MH-middle prefrontal, pre-, and postcentral gyri networks. In EW, higher connectivity of the LH-nucleus accumbens and LH-midbrain networks were associated with stress response. Higher connectivity in the LH-midbrain was also associated with a greater presence of emotional eating behaviors in EW. Conclusion: Adolescents with EW showed functional connectivity alterations within both MH/LH networks. Alterations in the LH network were linked with higher levels of stress response and emotional-driven eating patterns

Dielectric behavior of porous PMMA: From the micrometer to the nanometer scale

Producción CientíficaIn recent years, there has been a significant interest of the scientific community on nanocellular polymeric foams as a possible next generation of materials with a low dielectric constant for microelectronics applications In this work, the dielectric behavior of microcellular and nanocellular poly (methyl methacrylate) (PMMA) based foams has been characterized, both as a function of frequency and temperature, in order to analyze the effect of reducing the cell size to the nanoscale on the dielectric properties. Experimental results have shown clear differences in the dielectric behavior of the samples with cell sizes in the nanoscale as well as a sharp reduction of the dielectric constant when the porosity increases.Financial support from FPI grant BES-2013-062852 (B. Notario) from MINECO and FEDER program (MAT 2012-34901) MINECO, FEDER, UE (MAT2015-69234-R) and the Junta de Castile and Leon (VA035U13) are gratefully acknowledged

El autoengaño como mecanismo de mantenimiento de la adicción a las drogas

Background: This study was aimed at: (i) examining levels of self-deception in substance dependent individuals following addiction treatment, and (ii) examining the association between participants’ levels of self-deception and (a) personality disorders, (b) addiction-related beliefs, (c) duration of abstinence, and (d) estimates of craving. Method: We administered self-report questionnaires of self-deception and mixtification, and core beliefs related to addiction and craving. The sample comprised 79 outpatients who were consecutively recruited at the Centro Provincial de Drogodependencias in Granada: 87.3% were males and the mean age was 37.68 years old. Thirty-four percent of participants were diagnosed with comorbid personality disorders. Results: Results showed that individuals with substance dependence exhibit elevated scores of self-deception, particularly in the domains of active denial, selective amnesia, projection, and confabulation. Individuals with comorbid personality disorders display greater levels of self-deception compared to individuals without dual diagnosis. Conclusions: Moreover, there is a significant association between levels of self-deception and addiction-related beliefs and craving. In addition, there is a negative association between levels of self-deception and duration of abstinenceAntecedentes: los objetivos de este estudio fueron: (i) conocer el nivel de autoengaño de drogodependientes en tratamiento por su adicción, y (ii) estudiar la relación del autoengaño con (a) los trastornos de personalidad, (b) las creencias, (c) la abstinencia y (d) el craving en estos pacientes. Método: se utilizaron los cuestionarios de autoengaño y mixtificación (IAM) y de creencias relacionadas con el consumo de drogas y craving. La muestra estaba compuesta por 79 pacientes atendidos de forma consecutiva en el Centro Provincial de Drogodependencias de Granada. El 34.5% de los pacientes presentaban un trastorno de la personalidad. Resultados: los resultados mostraron que los drogodependientes obtienen puntuaciones elevadas en autoengaño, especialmente en los factores negación, amnesia selectiva, proyección y pensamiento fantaseado. Además, los pacientes con trastornos de la personalidad presentan niveles de autoengaño más elevados en comparación a los que no presentan este tipo de psicopatología, observándose una relación significativa entre las creencias nucleares relacionadas con el consumo y con el craving con el nivel de autoengaño. Conclusiones: se constata igualmente que el nivel de autoengaño se relaciona de forma negativa con el tiempo de abstinencia, lo que convierte al autoengaño en una diana terapéutica para mejorar el pronósticoS

Highly Deformable Porous Electromagnetic Wave Absorber Based on Ethylene-Propylene-Diene Monomer/Multiwall Carbon Nanotube Nanocomposites

The need for electromagnetic interference (EMI) shields has risen over the years as the result of our digitally and highly connected lifestyle. This work reports on the development of one such shield based on vulcanized rubber foams. Nanocomposites of ethylene-propylene-diene monomer (EPDM) rubber and multiwall carbon nanotubes (MWCNTs) were prepared via hot compression molding using a chemical blowing agent as foaming agent. MWCNTs accelerated the cure and led to high shear-thinning behavior, indicative of the formation of a 3D interconnected physical network. Foamed nanocomposites exhibited lower electrical percolation threshold than their solid counterparts. Above percolation, foamed nanocomposites displayed EMI absorption values of 28-45 dB in the frequency range of the X-band. The total EMI shielding efficiency of the foams was insignificantly affected by repeated bending with high recovery behavior. Our results highlight the potential of cross-linked EPDM/MWCNT foams as a lightweight EM wave absorber with high flexibility and deformability

頭部外傷の治療(交通事故による脳障害,第48回千葉医学会学術大会,第17回千葉県医師会学術大会,第10回日医医学講座,連合大会)

BACKGROUND:The negative consequences of energy dense foods are well known, yet people increasingly make unhealthy food choices leading to obesity (i.e., risky decisions). The aims of this study were: [1] to compare performance in decision-making tasks under risk and under ambiguity between individuals with obesity, overweight and normal weight; [2] to examine the associations between body mass index (BMI) and decision-making, and the degree to which these associations are modulated by reward sensitivity. METHODS:Seventy-nine adults were recruited and classified in three groups according to their BMI: obesity, overweight and normal-weight. Groups were similar in terms of age, education and socio-economic status, and were screened for comorbid medical and mental health conditions. Decision-making under risk was measured via the Wheel of Fortune Task (WoFT) and decision-making under ambiguity via the Iowa Gambling Task (IGT). Reward sensitivity was indicated by the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ). RESULTS:Individuals with obesity made riskier choices in the WoFT, specifically in choices with an expected value close to zero and in the propensity to risk index. No differences were found in IGT performance or SPSRQ scores. BMI was associated with risk-taking (WoFT performance), independently of reward sensitivity. CONCLUSIONS:Obesity is linked to a propensity to make risky decisions in experimental conditions analogous to everyday food choices

Altered decision-making under risk in obesity

Background: The negative consequences of energy dense foods are well known, yet people increasingly make unhealthy food choices leading to obesity (i.e., risky decisions). The aims of this study were: [1] to compare performance in decision-making tasks under risk and under ambiguity between individuals with obesity, overweight and normal weight; [2] to examine the associations between body mass index (BMI) and decision-making, and the degree to which these associations are modulated by reward sensitivity. Methods: Seventy-nine adults were recruited and classified in three groups according to their BMI: obesity, overweight and normal-weight. Groups were similar in terms of age, education and socio-economic status, and were screened for comorbid medical and mental health conditions. Decision-making under risk was measured via the Wheel of Fortune Task (WoFT) and decision-making under ambiguity via the Iowa Gambling Task (IGT). Reward sensitivity was indicated by the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ). Results: Individuals with obesity made riskier choices in the WoFT, specifically in choices with an expected value close to zero and in the propensity to risk index. No differences were found in IGT performance or SPSRQ scores. BMI was associated with risk-taking (WoFT performance), independently of reward sensitivity. Conclusions: Obesity is linked to a propensity to make risky decisions in experimental conditions analogous to everyday food choices

Poly(methyl methacrylate) as Healing Agent for Carbon Fibre Reinforced Epoxy Composites

Self-healing materials offer a potential solution to the problem of damage to fibre-reinforced plastics (FRPs) by allowing for the in-service repair of composite materials at a lower cost, in less time, and with improved mechanical properties compared to traditional repair methods. This study investigates for the first time the use of poly(methyl methacrylate) (PMMA) as a self-healing agent in FRPs and evaluates its effectiveness both when blended with the matrix and when applied as a coating to carbon fibres. The self-healing properties of the material are evaluated using double cantilever beam (DCB) tests for up to three healing cycles. The blending strategy does not impart a healing capacity to the FRP due to its discrete and confined morphology; meanwhile, coating the fibres with the PMMA results in healing efficiencies of up to 53% in terms of fracture toughness recovery. This efficiency remains constant, with a slight decrease over three subsequent healing cycles. It has been demonstrated that spray coating is a simple and scalable method of incorporating a thermoplastic agent into an FRP. This study also compares the healing efficiency of specimens with and without a transesterification catalyst and finds that the catalyst does not increase the healing efficiency, but it does improve the interlaminar properties of the material.This research was funded by the State Research Agency of Spain (AEI), under grant number PID2019-107501RB-I00/AEI/10.13039/50110001103

Long-term effectiveness of group cognitive-behavioral therapy for alcoholism: Impact of dual diagnosis on treatment outcome

El objetivo de este estudio fue analizar el resultado del tratamiento cognitivo-conductual grupal llevado a cabo en un centro ambulatorio para el tratamiento de las adicciones. La muestra estuvo compuesta por 130 hombres con trastorno por dependencia al alcohol. Se evaluaron los casos que reinician tratamiento tras el alta terapéutica en un rango de tiempo desde los dos años como mínimo hasta los 18. El 56.2% de la muestra finalizó el tratamiento con alta terapéutica, de los cuales el 75.3% no volvieron a iniciar tratamiento tras el alta, aumentando a 77.7% cuando el paciente completaba el periodo de revisión tras el alta. El 58% de los pacientes con trastornos de la personalidad finalizaron el tratamiento con alta terapéutica. El tratamiento cognitivo-conductual, cuyos componentes esenciales se detallan en este trabajo, es efectivo para el tratamiento grupal de los trastornos por dependencia del alcohol con comorbilidad de trastornos de la personalidad.The aim of the present study was to analyze the results of a cognitive-behavioral group therapy applied in an outpatient unit to treat drug addiction. The sample consisted of 130 males with an alcohol dependence disorder. Around 56% of the sample completed treatment – they were given therapeutic discharge. From those, 75.3% never resumed treatment, increasing to 77.7% when patients completed the check-up period after discharge. Follow-up from therapeutic discharge varies from 2 to 18 years; 58% of patients with personality disorders completed treatment with therapeutic discharge. Cognitive-behavioral treatment, whose essential components are detailed in the present study, is effective for the group treatment of patients with alcohol dependence and a comorbid personality disorder.Este estudio ha sido financiado por la Red de Trastornos Adictivos (Convocatoria RETICS 2012, Instituto de Salud Carlos III), Grupo Universidad de Granada