Comparative Study of Polyethylene Films Embedded with Oxide Nanoparticles of Granulated and Free-Standing Nature.

Nanocomposite polymer films are a very diverse research field due to their many applications. The search for low-cost, versatile methods, producing regulated properties of the final products, has thus become extremely relevant. We have previously reported a bulk-scale process, dispersing granulated metal oxide nanoparticles, of both unary and multi-component nature, in a low-density polyethylene (LDPE) polymer matrix, establishing a reference in the produced films' optical properties, due to the high degree of homogeneity and preservation of the primary particle size allowed by this method. In this work, unmodified, free-standing particles, namely zinc oxide (ZnO), titanium dioxide (TiO2), aluminum oxide (Al2O3), and silicon dioxide (SiO2) are blended directly with LDPE, and the optical properties of the fabricated films are compared to those of films made using the granulation process. The direct blending process evidently allows for control of the secondary particle size and ensures a homogeneous dispersion of the particles, albeit to a lesser extent than the granulation process. Despite the secondary particle size being comparatively larger than its granulated counterpart, the process still provides a regulated degree of deagglomeration of the free-standing oxide particles, so it can be used as a low-cost alternative. The regulation of the secondary particle size tunes the transmission and reflection spectra, in both unary and mixed oxide compositions. Finally, the direct blending process exhibits a clear ability to tune the energy band gap in mixed oxides.

Posttraumatic Stress Disorder is associated with altered reward mechanisms during the anticipation and the outcome of monetary incentive cues.

BACKGROUND: Recent studies suggest that Posttraumatic Stress Disorder (PTSD) might be associated with dysfunctional reward circuitry. However, further research is needed to understand the key role of the reward system in PTSD symptomatology. METHODS: Twenty participants with PTSD and 21 Trauma-Exposed matched Controls (TECs) completed the Monetary Incentive Delay (MID) task during an MRI session. Reaction times (RTs) and hit rates were recorded. Brain activity was investigated during the anticipation and the outcome of monetary gains and losses. RESULTS: During the anticipation of monetary loss, PTSD participants had higher RTs than TECs. However, the groups did not differ at the neurofunctional level. During successful avoidance of monetary loss, PTSD patients showed higher activation than TECs in the left caudate nucleus. During the anticipation of monetary gains, no differences in RTs were found between groups. PTSD patients had specific activations in the right amygdala, nucleus accumbens, putamen, and middle frontal gyrus (p < 0.05 family-wise error (FWE)-corrected), while TECs had specific activation in the anterior cingulate cortex. When obtaining monetary gains, PTSD patients had specific activation in the caudate nucleus, while TECs had specific activations in the right hypothalamus, subthalamic nucleus, and left inferior frontal gyrus. CONCLUSION: For the first time, functional brain activation during both the anticipation and the outcome of monetary rewards is reported altered in PTSD patients. These alterations might be associated with the complex symptomatology of PTSD.

Fear extinction learning improvement in PTSD after EMDR therapy: an fMRI study.

Objective: Neurobiological models of Posttraumatic Stress Disorder (PTSD) implicate fear processing impairments in the maintenance of the disorder. Eye Movement Desensitization and Reprocessing (EMDR) is one of the most efficient psychotherapies to treat PTSD. We aimed at exploring the brain mechanisms of the fear circuitry involved in PTSD patients' symptom remission after EMDR therapy. Method: Thirty-six PTSD participants were randomly assigned to either EMDR group receiving EMDR therapy or Wait-List (WL) group receiving supportive therapy. Participants underwent a behavioural fear conditioning and extinction paradigm during functional magnetic resonance (fMRI). In the EMDR group, patients were scanned at baseline, before EMDR and one week after remission. In the WL group, patients were scanned at baseline and within the same time interval as the EMDR group. Results: In the EMDR group after treatment, fear responses in the late extinction were significantly lower than before therapy. In parallel, significant functional activity and connectivity changes were found in the EMDR group versus the WL during the late extinction. These changes involve the fear circuit (amygdalae, left hippocampus), the right inferior frontal gyrus, the right frontal eye field and insula (pFWE < .05). Conclusion: These functional modifications underlie a significant improvement of fear extinction learning in PTSD patients after EMDR therapy.

Objetivo: Los modelos neurobiológicos del TEPT implican deficiencias en el procesamiento del miedo en el mantenimiento del trastorno. EMDR es una de las psicoterapias más eficaces para tratar el TEPT. Nuestro objetivo fue explorar los mecanismos cerebrales de los circuitos de miedo implicados en la remisión de los síntomas de los pacientes con el TEPT después de la terapia EMDR.Método: Treinta y seis participantes con el TEPT fueron asignados aleatoriamente a un grupo EMDR que recibió terapia EMDR o un grupo de Lista de Espera (LE) que recibió terapia de apoyo. Los participantes se sometieron a un paradigma de condicionamiento y extinción del miedo conductual durante la resonancia magnética funcional (fMRI). En el grupo EMDR, los pacientes fueron escaneados al inicio del estudio, antes de EMDR y una semana después de la remisión. En el grupo LE, los pacientes fueron escaneados al inicio y en el mismo intervalo de tiempo que el grupo EMDR.Resultados: En el grupo EMDR después del tratamiento, las respuestas de miedo en la extinción tardía fueron significativamente más bajas que antes de la terapia. En paralelo, se encontraron cambios significativos en la actividad funcional y en la conectividad en el grupo EMDR v/s el grupo LE durante la extinción tardía. Estos cambios involucran el circuito de miedo (amígdala, hipocampo izquierdo), el giro frontal inferior derecho, los campos del ojo frontal derecho y la ínsula (pFWE < .05).Conclusión: Estas modificaciones funcionales subyacen a una mejora significativa del aprendizaje de extinción del miedo en pacientes con el TEPT después de la terapia EMDR.

Grey matter density changes of structures involved in Posttraumatic Stress Disorder (PTSD) after recovery following Eye Movement Desensitization and Reprocessing (EMDR) therapy.

Recovery of stress-induced structural alterations in Posttraumatic Stress Disorder (PTSD) remains largely unexplored. This study aimed to determine whether symptoms improvement is associated with grey matter (GM) density changes of brain structures involved in PTSD. Two groups of PTSD patients were involved in this study. The first group was treated with Eye Movement Desensitization and Reprocessing (EMDR) therapy and recovered from their symptoms (recovery group) (n = 11); Patients were scanned prior to therapy (T1), one week (T2) and five months after the end of therapy (T3). The second group included patients which followed a supportive therapy and remained symptomatic (wait-list group) (n = 7). They were scanned at three time-steps mimicking the same inter-scan intervals. Voxel-based morphometry (VBM) was used to characterize GM density evolution. GM density values showed a significant group-by-time interaction effect between T1 and T3 in prefrontal cortex areas. These interaction effects were driven by a GM density increase in the recovery group with respect to the wait-list group. Symptoms removal goes hand-in-hand with GM density enhancement of structures involved in emotional regulation.