Self-Consistent Density-Functional Embedding: a Novel Approach for Density-Functional Approximations

In the present work, we introduce a Self-Consistent Density-Functional Embedding technique, which leaves the realm of standard energy-functional approaches in Density Functional Theory and targets directly the density-to-potential mapping that lies at its heart. Inspired by the Density Matrix Embedding Theory, we project the full system onto a set of small interacting fragments that can be solved accurately. Based on the rigorous relation of density and potential in Density Functional Theory, we then invert the fragment densities to local potentials. Combining these results in a continuous manner provides an update for the Kohn-Sham potential of the full system, which is then used to update the projection. The scheme proposed here converges to an accurate approximation for the density and the Kohn-Sham potential of the full system. Convergence to exact results can be achieved by increasing the fragment size. We find, however, that already for small embedded fragments accurate results are obtained. We benchmark our approach for molecular bond stretching in one and two dimensions and demonstrate that it reproduces the known steps and peaks that are present in the exact exchange-correlation potential with remarkable accuracy.Comment: 14 pages, 13 figure

Full-length amelogenin influences the differentiation of human dental pulp stem cells

Background: Amelogenin is an extracellular matrix protein well known for its role in the organization and mineralization of enamel. Clinically, it is used for periodontal regeneration and, due to its finding also in predentin and intercellular spaces of dental pulp cells, it has recently been suggested for pulp capping procedures. The aim of this study was to analyse in vitro the effect of the recombinant human full-length amelogenin on the growth and differentiation of human dental pulp stem cells (hDPSCs). Methods: Human DPSCs were treated with a supplement of amelogenin at a concentration of 10 ng/ml, 100 ng/ml and 1000 ng/ml. The groups were compared to the unstimulated control in terms of cell morphology and proliferation, mineralization and gene expression for ALP (alkaline phosphatase), DMP1 (dentin matrix protein-1) and DSPP (dentin sialophosphoprotein). Results: Amelogenin affects hDPSCs differently than PDL (periodontal ligament) cells and other cell lines. The proliferation rate at two weeks is significantly reduced in presence of the highest concentration of amelogenin as compared to the unstimulated control. hDPSCs treated with low concentrations present a downregulation of DMP1 and DSPP, which is significant for DSPP (p = 0.011), but not for DMP1 (p = 0.395). Conclusions: These finding suggest that the role of full-length amelogenin is not restricted to participation in tooth structure. It influences the differentiation of hDPSC according to various concentrations and this might impair the clinical results of pulp capping

Reliability of the fMRI-based assessment of self-evaluation in individuals with internet gaming disorder

The self-concept—defined as the cognitive representation of beliefs about oneself—determines how individuals view themselves, others, and their actions. A negative self-concept can drive gaming use and internet gaming disorder (IGD). The assessment of the neural correlates of self-evaluation gained popularity to assess the self-concept in individuals with IGD. This attempt, however, seems to critically depend on the reliability of the investigated task-fMRI brain activation. As first study to date, we assessed test–retest reliability of an fMRI self-evaluation task. Test–retest reliability of neural brain activation between two separate fMRI sessions (approximately 12 months apart) was investigated in N = 29 healthy participants and N = 11 individuals with pathological internet gaming. We computed reliability estimates for the different task contrasts (self, a familiar, and an unknown person) and the contrast (self > familiar and unknown person). Data indicated good test–retest reliability of brain activation, captured by the “self”, “familiar person”, and “unknown person” contrasts, in a large network of brain regions in the whole sample (N = 40) and when considering both experimental groups separately. In contrast to that, only a small set of brain regions showed moderate to good reliability, when investigating the contrasts (“self > familiar and unknown person”). The lower reliability of the contrast can be attributed to the fact that the constituting contrast conditions were highly correlated. Future research on self-evaluation should be cautioned by the findings of substantial local reliability differences across the brain and employ methods to overcome these limitations

PREDICTING PARTICIPATION IN AND SUCCESS OF A CONCURRENT SMOKING CESSATION PROGRAM DURING INPATIENT TREATMENT FOR ALCOHOL DEPENDENCE

Background: Predicting participation in and success of smoking cessation programs in alcohol dependent patients has yielded heterogeneous results. Moreover, these findings have rarely been based on prospective studies from clinical routine settings. Identifying predictors in prospective studies could help to tailor interventions that increase participation and success rates of smoking cessation therapies for these patients at a high risk for alcohol- and smoking-related morbidities and mortalities. Subjects and methods: During inpatient alcohol dependence treatment, 99 nicotine dependent patients were recruited. 73 patients chose to participate in a voluntary smoking cessation program. Interviews and questionnaires were used at baseline and at discharge to assess a large set of variables covering smoking and alcohol related factors, general psychopathology, quality of life and personality traits. Multiple logistic regression models were calculated to predict participation in the smoking cessation program and smoking abstinence at follow-up three months after discharge. Results: Participation in the smoking cessation program was predicted by higher stage of change, higher confidence in abstaining from smoking and lower perceived stress. Successful smoking cessation at follow-up was predicted by higher expectations of negative physical feelings due to smoking and lower expectations of temptations to smoke at baseline, and by lower number of daily smoked cigarettes at discharge. Conclusion: Despite the small sample size, this prospective study gives a first indication of clinically relevant predictors of participation in and success of a smoking cessation program by exploring many previously reported predictors simultaneously. The findings and their implications for treatment allocation and optimization are discussed. Key words

Prevalence Estimates of ADHD in a Sample of Inpatients With Alcohol Dependence

Objective: ADHD is common in patients with alcohol dependence, but prevalence results are inconsistent. We investigated ADHD prevalence in a complex design to avoid over- or underdiagnosing. Method: Patients with alcohol dependence starting long-term residential treatment were included. A structured interview (Diagnostic Interview for ADHD in Adults [DIVA]) was conducted on all patients. DIVA results indicating childhood or adulthood ADHD were assessed in successive diagnostic interviews by two expert clinicians. Results: 415 of 488 patients had completed the entire diagnostic assessment. ADHD prevalence was 20.5%. DIVA results correlated moderately with experts’ diagnoses. In patients with ADHD, a higher comorbid illicit substance use was prevalent and alcohol dependence started earlier and was more severe. Conclusion: This study provides the largest sample on ADHD prevalence in alcohol dependent inpatients. Despite great efforts to avoid overestimation, we found every fifth patient to have ADHD. ADHD diagnosis should not be based solely on a structured interview but should be clinically confirmed. (J. of Att. Dis. 2020; 24(14) 2072–2083

Lab meets real life : a laboratory assessment of spontaneous thought and its ecological validity

People's minds frequently wander towards self-generated thoughts, which are unrelated to external stimuli or demands. These phenomena, referred to as "spontaneous thought" (ST) and "mind wandering" (MW), have previously been linked with both costs and benefits. Current assessments of ST and MW have predominantly been conducted in the laboratory, whereas studies on the ecological validity of such lab-related constructs and their interrelations are rare. The current study examined the stability of ST dimensions assessed in the lab and their predictive value with respect to MW, repetitive negative thought (uncontrollable rumination, RUM), and affect in daily life. Forty-three university students were assessed with the Amsterdam Resting State Questionnaire (2nd version) to assess ten ST dimensions during the resting state in two laboratory sessions, which were separated by five days of electronic ambulatory assessment (AA). During AA, individuals indicated the intensity of MW and RUM, as well as of positive and negative affect in daily life ten times a day. ST dimensions measured in the lab were moderately stable across one week. Five out of ten ST lab dimensions were predicted by mental health-related symptoms or by dispositional cognitive traits. Hierarchical linear models revealed that a number of ST lab dimensions predicted cognitive and affective states in daily life. Mediation analyses showed that RUM, but not MW per se, accounted for the relationship between specific ST lab dimensions and mood in daily life. By using a simple resting state task, we could demonstrate that a number of lab dimensions of spontaneous thought are moderately stable, are predicted by mental health symptoms and cognitive traits, and show plausible associations with categories of self-generated thought and mood in daily life