Analisi della potenza termica rilasciata da un incendio di materiale plastico attraverso l’utilizzo di modelli di fluidodinamica computazionale.

Il presente lavoro di tesi si focalizza sulla possibilità di modellare la curva di potenza termica rilasciata (HRR – Heat Release Rate) in un incendio reale attraverso la simulazione CFD (Computational Fluid Dynamics), in particolare utilizzando il software FDS (Fire Dynamics Simulator). Nello specifico è analizzato un incendio di merce di materiale plastico da depositare all’interno di un magazzino, in cui la curva HRR è stata ricavata dai dati sperimentali di un fire-test seguendo l'approccio proposto dalla normativa NFPA 921. Tale norma propone di stimare la curva HRR attraverso una relazione semplificata che non tiene conto di alcuni fenomeni chimici e fisici che governano lo sviluppo dell’incendio; quindi, l’obiettivo della presente tesi è di ottenere un approccio più avanzato per la determinazione della curva HRR, da poter proporre per le simulazioni di studio della Fire Safety Engineering. Per realizzare la simulazione sono analizzati i vari modelli disponibili per la riproduzione dei fenomeni all’interno del software, confrontandoli tramite le curve HRR. L’impiego di un software CFD per la determinazione della curva di potenza termica rilasciata è risultato essere un approccio possibile; tuttavia, non è stata raggiunta l’indipendenza dei risultati dalla griglia di calcolo per la mancanza di risorse computazionali; pertanto allo stato attuale questo approccio è difficilmente applicabile in maniera ingegneristica ma in un futuro, ipotizzando di avere disponibili risorse di calcolo con potenze sempre maggiori, potrà essere utilizzato

Amygdala connectivity and aggression

Neurobiological models propose that reactive aggression is predicated on impairments in amygdala-prefrontal connectivity that subserves moral decision-making and emotion regulation. The amygdala is a key component within this neural network that modulates reactive aggression. We provide a review of amygdala dysfunctional brain networks leading to reactive aggressive behavior. We elaborate on key concepts, focusing on moral decision-making and emotion regulation in a developmental context, and brain network connectivity factors relating to amygdala (dys)function-factors which we suggest predispose to reactive aggression. We additionally discuss insights into the latest treatment interventions, providing the utilization of the scientific findings for practice.</p

Borderline personality disorder classification based on brain network measures during emotion regulation

Borderline Personality Disorder (BPD) is characterized by an increased emotional sensitivity and dysfunctional capacity to regulate emotions. While amygdala and prefrontal cortex interactions are regarded as the critical neural mechanisms underlying these problems, the empirical evidence hereof is inconsistent. In the current study, we aimed to systematically test different properties of brain connectivity and evaluate the predictive power to detect borderline personality disorder. Patients with borderline personality disorder (n = 51), cluster C personality disorder (n = 26) and non-patient controls (n = 44), performed an fMRI emotion regulation task. Brain network analyses focused on two properties of task-related connectivity: phasic refers to task-event dependent changes in connectivity, while tonic was defined as task-stable background connectivity. Three different network measures were estimated (strength, local efficiency, and participation coefficient) and entered as separate models in a nested cross-validated linear support vector machine classification analysis. Borderline personality disorder vs. non-patient controls classification showed a balanced accuracy of 55%, which was not significant under a permutation null-model, p = 0.23. Exploratory analyses did indicate that the tonic strength model was the highest performing model (balanced accuracy 62%), and the amygdala was one of the most important features. Despite being one of the largest data-sets in the field of BPD fMRI research, the sample size may have been limited for this type of classification analysis. The results and analytic procedures do provide starting points for future research, focusing on network measures of tonic connectivity, and potentially focusing on subgroups of BP

Borderline Personality Disorder classification based on brain network centrality during emotion regulation

Background: Borderline Personality Disorder is characterized by an increased emotional sensitivity and dysfunctional capacity to regulate emotions. While amygdala and prefrontal cortex interactions are regarded as the key neural mechanisms underlying these problems, the empirical evidence hereof is inconsistent. In the current study we aimed to systematically test different properties of brain connectivity and evaluate the predictive power to detect borderline personality disorder. Methods: Patients with borderline personality disorder (n=51), cluster C personality disorder (n=26) and non-patient controls (n=44) performed an fMRI emotion regulation task. Brain network analyses focused on two properties of task related connectivity: phasic refers to task-event dependent changes in connectivity while tonic was defined as task-stable background connectivity. Three different network measures were estimated (strength, local efficiency and participation coefficient) and then entered as separate models in a nested cross-validated linear support vector machine classification analysis. Results: Borderline personality disorder vs. non-patient controls classification showed a balanced accuracy of 55%, which was not significant under a permutation null-model, p=0.23. Exploratory analysis did indicate that the tonic strength model was the highest performing model (balanced accuracy 62%), and the amygdala was one of the most important features. Conclusions: Despite being one of the largest data-sets in the field of BPD fMRI research, the sample size may have been limited for this type of classification analyses. The results and analytic procedures do provide starting points for future research, focusing on network measures of tonic connectivity, and potentially focusing on subgroups of BPD

Always on guard: emotion regulation in women with borderline personality disorder compared to nonpatient controls and patients with cluster-C personality disorder

BACKGROUND: Borderline personality disorder (BPD) is characterized by emotion dysregulation; however, it is unclear whether this is restricted to negative emotional stimuli or to what degree this is specific to BPD. We investigated neural correlates of hypothesized increased emotional sensitivity and impaired emotion regulation in patients with BPD. METHODS: During fMRI scanning, patients with BPD, nonpatient controls and patients with cluster-C personality disorder completed an emotion regulation task, including negative, positive and erotic social pictures. RESULTS: We included 55 patients with BPD, 42 nonpatient controls and 24 patients with cluster-C personality disorder in our analyses. Passive viewing of negative stimuli resulted in greater activity in the anterior insula, temporoparietal junction and dorsolateral prefrontal cortex in patients with BPD than in nonpatient controls. The increased activity in the anterior insula and temporoparietal junction was also present when patients with BPD viewed positive stimuli. During regulation of negative stimuli compared with passive viewing, nonpatient controls showed greater activity in the dorsal anterior cingulate cortex, dorsolateral prefrontal cortex, middle temporal gyrus and bilateral inferior parietal lobule. Patients with BPD did not show this increase in activity. LIMITATIONS: Findings cannot be generalized to men, and patients represented a heterogeneous group regarding comorbid diagnoses and medication. CONCLUSION: When looking at emotional stimuli, patients with BPD showed a unique pattern of activity, suggesting an increase in brain activity involved in emotion generation. In the case of negative stimuli this is accompanied by increased activity in regulation areas. In contrast, increase of regulation processes seems absent when patients with BPD are explicitly instructed to regulate. Results of diagnosis specificity support a dimensional rather than a dichotomous differentiation between BPD and cluster-C personality disorder regarding emotional sensitivity and emotional regulation of social stimuli

Always on guard: emotion regulation in women with borderline personality disorder compared to nonpatient controls and patients with cluster-C personality disorder

Background: Borderline personality disorder (BPD) is characterized by emotion dysregulation; however, it is unclear whether this is restricted to negative emotional stimuli or to what degree this is specific to BPD. We investigated neural correlates of hypothesized increased emotional sensitivity and impaired emotion regulation in patients with BPD. Methods: During functional MRI (fMRI) scanning, patients with BPD, nonpatient controls and patients with cluster-C personality disorder completed an emotion regulation task, including negative, positive and erotic social pictures. Results: We included 55 patients with BPD, 42 nonpatient controls and 24 patients with cluster-C personality disorder in our analyses. Passive viewing of negative stimuli resulted in greater activity in the anterior insula, temporoparietal junction and dorsolateral prefrontal cortex in patients with BPD than in nonpatient controls. The increased activity in the anterior insula and temporoparietal junction was also present when patients with BPD viewed positive stimuli. During regulation of negative stimuli compared with passive viewing, nonpatient controls showed greater activity in the dorsal anterior cingulate cortex, dorsolateral prefrontal cortex, middle temporal gyrus and bilateral inferior parietal lobule. Patients with BPD did not show this increase in activity. Limitations: Findings cannot be generalized to men, and patients represented a heterogeneous group regarding comorbid diagnoses and medication. Conclusion: When looking at emotional stimuli, patients with BPD showed a unique pattern of activity, suggesting an increase in brain activity involved in emotion generation. In the case of negative stimuli this is accompanied by increased activity in regulation areas. In contrast, increase of regulation processes seems absent when patients with BPD are explicitly instructed to regulate. Results of diagnosis specificity support a dimensional rather than a dichotomous differentiation between BPD and cluster-C personality disorder regarding emotional sensitivity and emotional regulation of social stimul

Looking at the bigger picture:Cortical volume, thickness and surface area characteristics in borderline personality disorder with and without posttraumatic stress disorder

Borderline personality disorder (BPD) is a severe psychiatric disorder accompanied by multiple comorbidities. Neuroimaging studies have identified structural abnormalities in BPD with most findings pointing to gray matter volume reductions in the fronto-limbic network, although results remain inconsistent. Similar alterations were found in posttraumatic stress disorder (PTSD), a common comorbidity of BPD. Only a small number of studies have investigated structural differences in BPD patients regarding comorbid PTSD specifically and studies conducting additional surface analyses are scarce. We investigated structural differences in women with BPD with and without PTSD and non-patient controls. Automated voxel-based and region-based volumetric analyses were applied. Additionally, four surface-based measures were analyzed: cortical thickness, gyrification index, fractal dimension, and sulcus depth. Analyses did not identify cortical volume alterations in the fronto-limbic network. Instead, hypergyrification was detected in the right superior parietal cortex in BPD patients compared to nonpatient controls. No distinction was revealed between BPD patients with and without PTSD. These findings underline the importance of a holistic investigation examining volumetric and surface measures as these might enhance the understanding of structural alterations in BPD

Biased Attention to Facial Expressions of Ambiguous Emotions in Borderline Personality Disorder:An Eye-Tracking Study

Preliminary evidence suggests that biased attention could be crucial in fostering the emotion recognition abnormalities in borderline personality disorder (BPD). We compared BPD patients to Cluster-C personality disorder (CC) patients and non-patients (NP) regarding emotion recognition in ambiguous faces and their visual attention allocation to the eyes. The role of comorbid posttraumatic stress disorder (PTSD) in BPD regarding emotion recognition and visual attention was explored. BPD patients fixated the eyes of angry/happy, sad/happy, and fearful/sad blends longer than non-patients. This visual attention pattern was mainly driven by BPD patients with PTSD. This subgroup also demonstrated longer fixations than CC patients and a trend towards longer fixations than BPD patients without PTSD for the angry/happy and fearful/sad blends. Emotion recognition was not altered in BPD. Biased visual attention towards the eyes of ambiguous facial expressions in BPD might be due to trauma-related attentional bias rather than to impairments in facial emotion recognition

Neural correlates of intimate picture stimuli in females

Jacob et al. (2011) previously reported on intimate picture stimuli for emotion research in females in Psychiatry Research. Difficulties to engage in intimate relations constitute problems of many mental disorders, and intimacy must be differentiated from pure sex drive. Functional neuroimaging is an important tool to understand the pathophysiology of psychiatric disorders. We now studied cerebral activation in response to intimate stimuli in 35 healthy women. Comparison stimuli were taken from the International Affective Picture System. Neuroimaging revealed increased activation in bilateral occipitotemporal, parietal and anterior cingulate cortices extending to the orbitofrontal area. These data reflect cognitive, emotional and motivational compounds congruent with previous neuroimaging data of attachment and long term romantic relationships. Lateral prefrontal, posterior insular regions and the fusiform face area were more active during control images. Our data present a solid basis for use in psychiatric samples