Interfacial Charge Density and Its Connection to Adhesion and Frictional Forces

We derive a connection between the intrinsic tribological properties and the electronic properties of a solid interface. In particular, we show that the adhesion and frictional forces are dictated by the electronic charge redistribution occurring due to the relative displacements of the two surfaces in contact. We define a figure of merit to quantify such a charge redistribution and show that simple functional relations hold for a wide series of interactions including metallic, covalent, and physical bonds. This suggests unconventional ways of measuring friction by recording the evolution of the interfacial electronic charge during sliding. Finally, we explain that the key mechanism to reduce adhesive friction is to inhibit the charge flow at the interface and provide examples of this mechanism in common lubricant additives

Facets of clinicians' anxiety and the delivery of cognitive behavioral therapy.

Psychological therapists commonly fail to adhere to treatment protocols in everyday clinical practice. In part, this pattern of drift is attributable to anxious therapists being less likely to undertake some elements of evidence-based therapies - particularly the exposure-based elements. This study considers what facets of anxiety (cognitive, behavioral, physiological) are related to junior clinicians' reported use of cognitive-behavioral therapy techniques. Thirty-two clinicians (mean age = 28.9 years; mean length of CBT experience = 1.5 years; 23 female, nine male) who offered CBT were assessed for their cognitive, behavioral and physiological characteristics (Intolerance of Uncertainty scale; risk taking; skin conductance response and heart rate variability). While the three different facets of anxiety were relatively poorly associated with each other, as is usual in this literature, each facet was linked differently to the reported delivery of CBT techniques (P < .05). Overall, higher anxiety levels were associated with a poorer use of exposure methods or with a greater use of other behavioral or cognitive methods. Of the three facets of anxiety, only physiological reactivity showed an association with the clinicians' temporal characteristics, with more experienced therapists being more likely to have greater skin conductance responses to positive and negative outcomes. These findings suggest that clinicians who are more anxious are less likely to deliver the full evidence-based form of CBT and to focus instead on less challenging elements of the therapy. Potential ways of overcoming this limitation are discussed

Comparison of person-centred and cumulative risk approaches in explaining the relationship between adverse childhood experiences and behavioural and emotional problems

Adverse childhood experiences (ACEs) commonly co-occur, and researchers often estimate their impact using a cumulative risk approach. The person-centred approach offers another approach to operationalise the co-occurrence of ACEs. This study aims to estimate latent classes of ACEs in a sample of UK children, examine their relationship with emotional and behavioural problems, and compare the explanatory value of the latent classes to cumulative risk scores. Data were collected among a general population sample of British 10-year-old children extracted from the UK Household Longitudinal Study (N = 601). Seven items characterised ACEs, comprising parent-report physical discipline, emotional abuse, supervisory neglect, maternal psychological distress, and child-report parental educational disinterest, bullying victimisation, and adverse neighbourhood. Outcome measures were derived from the self-report Strengths and Difficulties Questionnaire including total difficulties, emotional symptoms, conduct problems, hyperactivity, peer problems, and prosocial behaviour. Latent class analysis resulted in a 3-class solution: low ACEs, household challenges, community challenges. Compared to the other classes, the community challenges class scored substantially worse on total difficulties, emotional symptoms, and peer subscales. The cumulative risk score was associated with all outcomes except prosocial behaviour. Cumulative risk models accounted for a larger proportion of variance compared with the latent class models, except for peer problems which the person-centred model explained better. This study confirms that ACEs are associated with impairment in child functioning, and that both person-centred and cumulative risk approaches can capture this relationship well. Specifically, the person-centred approach demonstrated how co-occurring risks factors in the community challenges class produced particularly poor internalising outcomes

Factors impacting resilience as a result of exposure to COVID-19 : the ecological resilience model

Despite the severe psychological impact of the COVID-19 pandemic, some individuals do not develop high levels of psychological distress and can be termed resilient. Using the ecological resilience model, we examined factors promoting or hindering resilience in the COVID-19 pandemic. Of the 1034 participants (49.9±16.2 years; females 51.2%) from Italian general population, 70% displayed resilient outcomes and 30% reported moderate-severe anxiety and/or depression. A binary regression model revealed that factors promoting resilience were mostly psychological (e.g., trait resilience, conscientiousness) together with social distancing. Conversely, factors hindering resilience included COVID-19-anxiety, COVID-19-related PTSD symptoms, intolerance of uncertainty, loneliness, living with children, higher education, and living in regions where the virus was starting to spread. In conclusion, the ecological resilience model in the COVID-19 pandemic explained 64% of the variance and identified factors promoting or hindering resilient outcomes. Critically, these findings can inform psychological interventions supporting individuals by strengthening factors associated with resilience

Rabbia, alessitimia, impulsività in pazienti affetti da schizofrenia e autori di reato: uno studio trasversale

Background: Anger, alexithymia, impulsivity are clinical variables underlying aggression/crimes, therefore their evaluation with specific instruments in psychiatric patients samples could give the clinician deeper knowledge and useful information aimed to the rehabilitative work and the prevention of recidivism. Materials and Methods: 53 people with Schizofrenia, sectioned at the Barcellona Pozzo di Gotto Forensic Hospital – before its dismissing -, have completed STAXI-2, TAS-20, BIS-11 questionnaires.Exclusion criteria: Intellectual Disability. Pearson linear correlations have been performed to test associations between the three variables of anger, alexithymia, impulsivity and between a single variable and crimes. Logistic regressions have been used to further investigate links between clinical variables and crimes. Results: Correlations between variables: a) 17 alexithymic patients (TAS&gt;60), mean score BIS-11: 58. Positive Pearson correlation between alexithymia and impulsivity; b) STAXI-2 RS/S, R/T, RT/T, RT/R, ER/IN are positively related to alexithymia; CR/IN e CR/OUT in a negative way; c) Impulsivity is related to STAXI-2 RT/T, ER/IN in a significant way. Correlations between variables and crimes: d) As TAS-20 scores increase, there is lower probability to commit a crime inside the family; e) As BIS-11 scores increase, there is lower probability to commit homicide; f) STAXI-2 RS/S is positively related to robbery. Discussion and conclusions: Our results about alexithymia and impulsivity, alexithymia and anger, and impulsivity and anger correlations go along with the literature about aggression/violence antecedents. Alexithymic subjects would commit crimes outside the family and murderers – in our sample – would have committed “low level of impulsivity” homicides, as far as the premeditation factor is concerned. Robbery is related to RS/S (feeling anger), to indicate how anger is manifested in such crimes.Background: Rabbia, alessitimia, impulsività sono variabili cliniche sottese ad agiti aggressivi/reati, pertanto il loro studio e rilevazione con strumenti testali in campioni di soggetti affetti da malattia mentale può consentire al clinico una conoscenza psicopatologica più approfondita e fornire informazioni utili per la riabilitazione e prevenzione delle recidive. Materiali e Metodi: 53 persone affette da Schizofrenia, internate presso l’Ospedale Psichiatrico Giudiziario di Barcellona Pozzo di Gotto prima dellasua chiusura hanno svolto i questionari STAXI-2, TAS-20, BIS-11. Criterio di esclusione: diagnosi di Disabilità Intellettiva. Sono state svolte correlazioni lineari di Pearson per testare possibili associazioni tra le variabili rabbia, alessitimia, impulsività e tra le singole variabili e le tipologie di reati commessi. Ulteriori approfondimenti per il legame tra stati emotivi e reati sono stati svolti con regressione logistica (reato commesso/non commesso). Risultati: Correlazioni tra variabili: a) 17 soggetti alessitimici (TAS&gt;60), punteggio medio BIS-11: 58. Correlazione di Pearson positiva e statisticamente significativa tra alessimia e impulsività; b) Le sottoscale STAXI-2 RS/S, R/T, RT/T, RT/R, ER/IN si correlano in modo statisticamente significativo all’alessitimia, CR/IN e CR/OUT in modo negativo; c) Impulsività si correla in modo statisticamente significativo alle sottoscale STAXI-2 RT/T, ER/IN. Correlazioni variabili-reati: d) All’aumento di punteggi di TAS-20, vi è una minore probabilità di commettere reati in famiglia; e) All’aumento di punteggi di BIS-11, vi è una minore probabilità di commettere omicidio; f) La sottoscala STAXI-2 RS/S è correlata positivamente con la rapina. Discussione e conclusioni: I risultati ottenuti in merito alle correlazioni tra alessitimia e impulsività, alessitimia e rabbia, impulsività e rabbia sono concordi con la letteratura esistente rispetto agli antecedenti di comportamenti aggressivi e violenti. Soggetti alessitimici tenderebbero a commettere reati al di fuori della famiglia e i soggetti autori di omicidio – nel campione in esame – avrebbero commesso omicidi “a basso livello di impulsività”, per componente di premeditazione. Il reato rapina si correla con la sottoscala “sentire rabbia” (RS/S), ad indicare come la componente rabbiosa si slatentizzi in questo tipo di reati.

Convergent Processing of Both Positive and Negative Motivational Signals by the VTA Dopamine Neuronal Populations

Dopamine neurons in the ventral tegmental area (VTA) have been traditionally studied for their roles in reward-related motivation or drug addiction. Here we study how the VTA dopamine neuron population may process fearful and negative experiences as well as reward information in freely behaving mice. Using multi-tetrode recording, we find that up to 89% of the putative dopamine neurons in the VTA exhibit significant activation in response to the conditioned tone that predict food reward, while the same dopamine neuron population also respond to the fearful experiences such as free fall and shake events. The majority of these VTA putative dopamine neurons exhibit suppression and offset-rebound excitation, whereas ∼25% of the recorded putative dopamine neurons show excitation by the fearful events. Importantly, VTA putative dopamine neurons exhibit parametric encoding properties: their firing change durations are proportional to the fearful event durations. In addition, we demonstrate that the contextual information is crucial for these neurons to respectively elicit positive or negative motivational responses by the same conditioned tone. Taken together, our findings suggest that VTA dopamine neurons may employ the convergent encoding strategy for processing both positive and negative experiences, intimately integrating with cues and environmental context

Contribution of limbic norepinephrine to cannabinoid-induced aversion

RATIONALE: The cannabinoid system has risen to the forefront in the development of novel treatments for a number of pathophysiological processes. However, significant side effects have been observed in clinical trials raising concerns regarding the potential clinical utility of cannabinoid-based agents. Understanding the neural circuits and neurochemical substrates impacted by cannabinoids will provide a better means of gaging their actions within the central nervous system that may contribute to the expression of unwanted side effects. OBJECTIVES: In the present study, we investigated whether norepinephrine (NE) in the limbic forebrain is a critical determinant of cannabinoid receptor agonist-induced aversion and anxiety in rats. METHODS: An immunotoxin lesion approach was combined with behavioral analysis using a place conditioning paradigm and the elevated zero maze. RESULTS: Our results show that the non-selective CB1/CB2 receptor agonist, WIN 55,212-2, produced a significant place aversion in rats. Further, NE in the nucleus accumbens was critical for WIN 55,212-2-induced aversion but did not affect anxiety-like behaviors. Depletion of NE from the bed nucleus of the stria terminalis was ineffective in altering WIN 55,212-2-induced aversion and anxiety. CONCLUSIONS: These results indicate that limbic, specifically accumbal, NE is required for cannabinoid-induced aversion but is not essential to cannabinoid-induced anxiety.This works was supported by PHS grant DA 020129. Ana Franky Carvalho was supported by the Portuguese Foundation for Science and Technology (SFRH/BD/33236/2007)

Attention Enhances the Retrieval and Stability of Visuospatial and Olfactory Representations in the Dorsal Hippocampus

Attention enhances the encoding and retrieval of olfactory and visuospatial representations by modulating place field stability, firing rate, and neuronal synchronization of pyramidal cells in the hippocampus

Microstructural Abnormalities in Subcortical Reward Circuitry of Subjects with Major Depressive Disorder

Previous studies of major depressive disorder (MDD) have focused on abnormalities in the prefrontal cortex and medial temporal regions. There has been little investigation in MDD of midbrain and subcortical regions central to reward/aversion function, such as the ventral tegmental area/substantia nigra (VTA/SN), and medial forebrain bundle (MFB).We investigated the microstructural integrity of this circuitry using diffusion tensor imaging (DTI) in 22 MDD subjects and compared them with 22 matched healthy control subjects. Fractional anisotropy (FA) values were increased in the right VT and reduced in dorsolateral prefrontal white matter in MDD subjects. Follow-up analysis suggested two distinct subgroups of MDD patients, which exhibited non-overlapping abnormalities in reward/aversion circuitry. The MDD subgroup with abnormal FA values in VT exhibited significantly greater trait anxiety than the subgroup with normal FA values in VT, but the subgroups did not differ in levels of anhedonia, sadness, or overall depression severity.These findings suggest that MDD may be associated with abnormal microstructure in brain reward/aversion regions, and that there may be at least two subtypes of microstructural abnormalities which each impact core symptoms of depression