Coexistence of antiferrodistortive and ferroelectric distortions at the PbTiO3_3 (001) surface

The c(2$\times$2) reconstruction of (001) PbTiO$_3$ surfaces is studied by means of first principles calculations for paraelectric (non-polar) and ferroelectric ([001] polarized) films. Analysis of the atomic displacements in the near-surface region shows how the surface modifies the antiferrodistortive (AFD) instability and its interaction with ferroelectric (FE) distortions. The effect of the surface is found to be termination dependent. The AFD instability is suppressed at the TiO$_2$ termination while it is strongly enhanced, relative to the bulk, at the PbO termination resulting in a c(2x2) surface reconstruction which is in excellent agreement with experiments. We find that, in contrast to bulk PbTiO$_3$, in-plane ferroelectricity at the PbO termination does not suppress the AFD instability. The AFD and the in-plane FE distortions are instead concurrently enhanced at the PbO termination. This leads to a novel surface phase with coexisting FE and AFD distortions which is not found in PbTiO$_3$ bulk

The relationship between dose and serotonin transporter occupancy of antidepressants-a systematic review

Contains fulltext : 252198.pdf (Publisher’s version ) (Open Access)Brain imaging techniques enable the visualization of serotonin transporter (SERT) occupancy as a measure of the proportion of SERT blocked by an antidepressant at a given dose. We aimed to systematically review the evidence on the relationship between antidepressant dose and SERT occupancy. We searched PubMed and Embase (last search 20 May 2021) for human in vivo, within-subject PET, or SPECT studies measuring SERT occupancy at any dose of any antidepressant with highly selective radioligands ([(11)C]-DASB, [(123)I]-ADAM, and [(11)C]-MADAM). We summarized and visualized the dose-occupancy relationship for antidepressants across studies, overlaying the plots with a curve based on predicted values of a standard 2-parameter Michaelis-Menten model fitted using the observed data. We included seventeen studies of 10 different SSRIs, SNRIs, and serotonin modulators comprising a total of 294 participants, involving 309 unique occupancy measures. Overall, following the Michaelis-Menten equation, SERT occupancy increased with a higher dose in a hyperbolic relationship, with occupancy increasing rapidly at lower doses and reaching a plateau at approximately 80% at the usual minimum recommended dose. All the studies were small, only a few investigated the same antidepressant, dose, and brain region, and few reported information on factors that may influence SERT occupancy. The hyperbolic dose-occupancy relationship may provide mechanistic insight of relevance to the limited clinical benefit of dose-escalation in antidepressant treatment and the potential emergence of withdrawal symptoms. The evidence is limited by non-transparent reporting, lack of standardized methods, small sample sizes, and short treatment duration. Future studies should standardize the imaging and reporting procedures, measure occupancy at lower antidepressant doses, and investigate the moderators of the dose-occupancy relationship

Den danske dyrkningsjords tilstand og kvalitet - konsekvenser af trafik og jordbearbejdning

Et alsidigt sædskifte og/eller tilførsel af organisk stof til jorden giver en god jordkvalitet (her defineret som en gunstig jordstruktur). Ensidige driftsformer kan i sig selv give anledning til en dårlig jordkvalitet. Jordpakning via trafik på jorden kan eliminere de gode effekter af et godt sædskifte og tilførsel af organisk stof. Trafik på jorden og i endnu højere grad intensiv jordbearbejdning øger risikoen for, at jordens lermineraler dispergeres til vandfasen. Dette kan give tilslemning og skorpedannelse på jorden og indebærer endvidere en risiko for nedvaskning af de vigtige lermineraler fra dyrkningslaget. Der bør foretages undersøgelser af omfanget af denne proces med de i dag anvendte bearbejdningsteknikker. Komprimering af jorden under normal bearbejdningsdybde via pløjning med hjulet i furebunden og via kørsel med meget tunge maskiner er i dag en realitet for stort set hele den danske landbrugsjord. Det anbefales stærkt, at landbruget overgår til pløjesystemer med alle fire hjul ’på land’ (’on-land’ pløjning). Det anbefales ligeledes, at belastningen (vægten) ved kørsel på forårs- og efterårsvåd jord ikke overstiger 6 tons på enkelt-aksel og 8-10 tons på boogi-aksel. Anvendelse af bæltekøretøjer er muligvis en løsning på pakningsproblemet. Det forudsætter dog, at de anvendte maskiner giver anledning til reelt meget lave marktryk (<50 kPa) over hele trædefladen. Der bør gennemføres flere undersøgelser af, hvorvidt de i dag tilgængelige bæltekøretøjer opfylder disse kriterier ved alle arbejdsoperationer

Metabolic profile in patients with newly diagnosed bipolar disorder and their unaffected first-degree relatives

Abstract Objective The prevalence of metabolic syndrome and insulin resistance is twice as high in patients with bipolar disorder compared with the general population, and possibly associated with a disabling illness trajectory of bipolar disorder, an increased risk of cardiovascular disease and premature death. Despite these detrimental effects, the prevalence of metabolic syndrome and insulin resistance in patients newly diagnosed with bipolar disorder and their unaffected first-degree relatives is largely unknown. Methods In a cross-sectional study of 206 patients with newly diagnosed bipolar disorder, 50 of their unaffected first-degree relatives and 109 healthy age- and sex-matched individuals, we compared the prevalence of metabolic syndrome and insulin resistance (HOMA-IR). In patients with bipolar disorder, we further investigated illness and medication variables associated with the metabolic syndrome and insulin resistance. Results Higher rates of metabolic syndrome (odds ratio = 3.529, 95% CI 1.378–9.041, P = 0.009) and levels of insulin resistance (B = 1.203, 95% CI 1.059–1.367, P = 0.005) were found in patients newly diagnosed with bipolar disorder, but not in their unaffected first-degree relatives compared with matched healthy individuals (data adjusted for sex and age). Most patients with bipolar disorder (94.7%) were diagnosed within the preceding 2 years, and the average illness duration, defined as time from first mood episode, was 10 years. Conclusion Our findings of elevated prevalence of metabolic syndrome and insulin resistance in patients with newly diagnosed bipolar disorder highlight the importance of screening for these conditions at an early stage to employ adequate and early care reducing the risk of cardiovascular disease and premature death

The risks of adverse events with venlafaxine and mirtazapine versus 'active placebo', placebo, or no intervention for adults with major depressive disorder: a protocol for two separate systematic reviews with meta-analysis and Trial Sequential Analysis

BACKGROUND: Major depressive disorder causes a great burden on patients and societies. Venlafaxine and mirtazapine are commonly prescribed as second-line treatment for patients with major depressive disorder worldwide. Previous systematic reviews have concluded that venlafaxine and mirtazapine reduce depressive symptoms, but the effects seem small and may not be important to the average patient. Moreover, previous reviews have not systematically assessed the occurrence of adverse events. Therefore, we aim to investigate the risks of adverse events with venlafaxine or mirtazapine versus 'active placebo', placebo, or no intervention for adults with major depressive disorder in two separate systematic reviews. METHODS: This is a protocol for two systematic reviews with meta-analysis and Trial Sequential Analysis. The assessments of the effects of venlafaxine or mirtazapine will be reported in two separate reviews. The protocol is reported as recommended by Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols, risk of bias will be assessed with the Cochrane risk-of-bias tool version 2, clinical significance will be assessed using our eight-step procedure, and the certainty of the evidence will be assessed with the Grading of Recommendations Assessment, Development and Evaluation approach. We will search for published and unpublished trials in major medical databases and trial registers. Two review authors will independently screen the results from the literature searches, extract data, and assess risk of bias. We will include published or unpublished randomised clinical trial comparing venlafaxine or mirtazapine with 'active placebo', placebo, or no intervention for adults with major depressive disorder. The primary outcomes will be suicides or suicide attempts, serious adverse events, and non-serious adverse events. Exploratory outcomes will include depressive symptoms, quality of life, and individual adverse events. If feasible, we will assess the intervention effects using random-effects and fixed-effect meta-analyses. DISCUSSION: Venlafaxine and mirtazapine are frequently used as second-line treatment of major depressive disorder worldwide. There is a need for a thorough systematic review to provide the necessary background for weighing the benefits against the harms. This review will ultimately inform best practice in the treatment of major depressive disorder. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42022315395

Psychotic experiences are associated with health anxiety and functional somatic symptoms in preadolescence

Background: Health anxiety (HA) is an increasing public health problem related to increased health service costs, and associated with functional somatic symptoms (FSS) and considerable personal suffering. Abnormal bodily experiences which may resemble HA and FSS are common in psychotic disorders, but a potential link between HA and psychosis vulnerability in childhood is largely unexplored. The current study estimates the association between subclinical psychotic experiences (PE) and HA and FSS in a general population cohort of preadolescents. Methods: The study population consisted of 1,572 11–12-year-old children from the Copenhagen Child Cohort 2000. PE were comprehensibly assessed as either present or not present using the Kiddie Schedule of Affective Disorders and Schizophrenia psychosis section. HA and FSS were assessed by self-report on validated questionnaires. Additional variables on general psychopathology, puberty, and chronic somatic illness were also obtained. Results: Psychotic experiences were associated with the top 10% high scores of HA (Odds Ratio (OR) 3.2; 95% CI: 2.1–4.8) and FSS (OR 4.6; 95% CI: 3.1–6.9) in univariate analyses. After mutual adjustment, the association was reduced to (HA: OR 2.3; 95% CI: 1.5–3.5; FSS: OR 3.7; 95% CI: 2.4–4.7), suggesting interdependence. Further adjustment for potential confounders and general psychopathology only reduced the associations slightly: HA OR 2.2 (95% CI: 1.4–3.4); FSS OR 3.3 (95% CI: 2.1–5.2). Secondary analyses of subdimensions of HA showed that PE were associated with fears (OR 3.0; 95% CI: 2.0–4.6) and daily impact of HA symptoms (OR 5.0; 95% CI: 3.4–7.5), but not help seeking (OR 1.2; 95% CI: 0.7–2.1). Conclusions: This is the first study to investigate the associations between PE and HA and FSS, respectively. PE were significantly associated with HA and FSS over and above general psychopathology in preadolescence. Individuals with PE expressed high levels of health-related fears and daily impact, but no corresponding help-seeking behavior

Island dynamics and anisotropy during vapor phase epitaxy of m-plane GaN

Using in situ grazing-incidence x-ray scattering, we have measured the diffuse scattering from islands that form during layer-by-layer growth of GaN by metal-organic vapor phase epitaxy on the (101⎯⎯0)(101¯0)(101¯0) m-plane surface. The diffuse scattering is extended in the (0001)(0001)(0001) in-plane direction in reciprocal space, indicating a strong anisotropy with islands elongated along [12⎯⎯10][12¯10] [12¯10] and closely spaced along [0001][0001][0001]. This is confirmed by atomic force microscopy of a quenched sample. Islands were characterized as a function of growth rate F and temperature. The island spacing along [0001][0001][0001] observed during the growth of the first monolayer obeys a power-law dependence on growth rate F−nF−nF−n, with an exponent n=0.25±0.02n=0.25±0.02n=0.25±0.02. The results are in agreement with recent kinetic Monte Carlo simulations, indicating that elongated islands result from the dominant anisotropy in step edge energy and not from surface diffusion anisotropy. The observed power-law exponent can be explained using a simple steady-state model, which gives n = 1/4