Coronary artery restenosis treatment with plain balloon, drug-coated balloon, or drug-eluting stent: 10-year outcomes of the ISAR-DESIRE 3 trial.

AIMS: The best interventional strategy for the treatment of drug-eluting stent (DES) in-stent restenosis (ISR) is still unclear and no data from randomized trials beyond 3-year follow-up are available. We aimed to define 10-year comparative efficacy and safety of plain balloon (PB), paclitaxel-coated balloon (PCB), and paclitaxel-eluting stent (PES) for percutaneous coronary intervention (PCI) of DES-ISR. METHODS AND RESULTS: Clinical follow-up of patients randomly assigned to PB, PCB, and PES in the ISAR-DESIRE 3 trial was extended to 10 years and events were independently adjudicated. The primary endpoint was a composite of cardiac death, target vessel myocardial infarction, target lesion thrombosis, or target lesion revascularization. The major secondary safety endpoint was a composite of cardiac death, target vessel myocardial infarction, or target lesion thrombosis. The major secondary efficacy endpoint was target lesion revascularization. Incidences by the Kaplan-Meier method were compared by the log-rank test. Risk estimation was primarily performed by Cox proportional hazards regression and supplemented by weighted Cox regression accounting for non-proportional hazards and Royston-Parmar flexible parametric regression with a time-varying coefficient. Primary results were further assessed by landmark, lesion-level, per-protocol, and competing risk analyses. A total of 402 patients (500 lesions) with DES-ISR were randomly assigned to PB angioplasty (134 patients, 160 lesions), PCB angioplasty (137 patients, 172 lesions), and PES implantation (131 patients, 168 lesions). Clinical follow-up did not significantly differ among treatments [PB, 9.62 (4.50-10.02) years; PCB, 10.01 (5.72-10.02) years; PES, 9.08 (3.14-10.02) years; P = 0.300]. At 10 years, the primary composite endpoint occurred in 90 patients (72.0%) assigned to PB, 70 patients (55.9%) assigned to PCB, and 72 patients (62.4%) assigned to PES (P < 0.001). The pairwise comparison between PCB and PES resulted in a non-significant difference [multiplicity-adjusted P = 0.610; Grambsch-Therneau P = 0.004; weighted Cox: hazard ratio (HR) 1.10, 95% confidence interval (CI) 0.80-1.51; Cox: HR 1.10, 95% CI 0.79-1.52; Royston-Parmar: HR 1.08, 95% CI 0.72-1.60]. The major secondary safety endpoint occurred in 39 patients (34.1%) assigned to PB, 39 patients (34.0%) assigned to PCB, and 42 patients (40.0%) assigned to PES (P = 0.564). Target lesion revascularization occurred in 71 patients (58.0%) assigned to PB, 55 patients (43.9%) assigned to PCB, and 42 patients (38.6%) assigned to PES (P < 0.0001). The pairwise comparison between PES and PCB resulted in a non-significant difference (multiplicity-adjusted P = 0.282; Grambsch-Therneau P = 0.002; weighted Cox: HR 0.83, 95% CI 0.56-1.22; Cox: HR 0.81, 95% CI 0.54-1.21; Royston-Parmar: HR 0.75, 95% CI 0.47-1.20). Lesion-level and per-protocol analyses were consistent. At landmark analyses, an excess of death and cardiac death associated with PES compared with PCB was observed within 5 years after PCI, though 10-year differences did not formally reach the threshold of statistical significance after adjustment for multiplicity. Competing risk regression confirmed a non-significant difference in target lesion revascularization between PCB and PES and showed an increased risk of death associated with PES compared with PCB. CONCLUSION: Ten years after PCI for DES-ISR, the primary and major secondary endpoints between PCB and PES were not significantly different. However, an excess of death and cardiac death within 5 years associated with PES and the results of the competing risk analysis are challenging to interpret and warrant further analysis. PES and PCB significantly reduced target lesion revascularization compared with PB.

oREV: An item response theory-based open receptive vocabulary task for 3- to 8-year-old children.

Individual differences in early language abilities are an important predictor of later life outcomes. High-quality, easy-access measures of language abilities are rare, especially in the preschool and primary school years. The present study describes the construction of a new receptive vocabulary task for children between 3 and 8 years of age. The task was implemented as a browser-based web application, allowing for both in-person and remote data collection via the internet. Based on data from N = 581 German-speaking children, we estimated the psychometric properties of each item in a larger initial item pool via item response modeling. We then applied an automated item selection procedure to select an optimal subset of items based on item difficulty and discrimination. The so-constructed task has 22 items and shows excellent psychometric properties with respect to reliability, stability, and convergent and discriminant validity. The construction, implementation, and item selection process described here makes it easy to extend the task or adapt it to different languages. All materials and code are freely accessible to interested researchers. The task can be used via the following website: https://ccp-odc.eva.mpg.de/orev-demo .

A data management infrastructure for the integration of imaging and omics data in life sciences.

BACKGROUND: As technical developments in omics and biomedical imaging increase the throughput of data generation in life sciences, the need for information systems capable of managing heterogeneous digital assets is increasing. In particular, systems supporting the findability, accessibility, interoperability, and reusability (FAIR) principles of scientific data management. RESULTS: We propose a Service Oriented Architecture approach for integrated management and analysis of multi-omics and biomedical imaging data. Our architecture introduces an image management system into a FAIR-supporting, web-based platform for omics data management. Interoperable metadata models and middleware components implement the required data management operations. The resulting architecture allows for FAIR management of omics and imaging data, facilitating metadata queries from software applications. The applicability of the proposed architecture is demonstrated using two technical proofs of concept and a use case, aimed at molecular plant biology and clinical liver cancer research, which integrate various imaging and omics modalities. CONCLUSIONS: We describe a data management architecture for integrated, FAIR-supporting management of omics and biomedical imaging data, and exemplify its applicability for basic biology research and clinical studies. We anticipate that FAIR data management systems for multi-modal data repositories will play a pivotal role in data-driven research, including studies which leverage advanced machine learning methods, as the joint analysis of omics and imaging data, in conjunction with phenotypic metadata, becomes not only desirable but necessary to derive novel insights into biological processes.

Long-term clinical outcomes after drug eluting stent implantation with and without stent overlap.

OBJECTIVE: The aim of this study was to investigate the impact of drug eluting stent (DES) overlap on clinical outcomes after percutaneous coronary intervention (PCI). BACKGROUND: While the use of overlapping bare metal stent has been associated with an increased risk of adverse clinical events, the long-term impact of DES overlap on clinical outcomes is not certain at present. Similarly, the effect of different DES generations and polymer types on DES overlap associated clinical outcomes has not previously been comprehensively elucidated. METHODS: We analyzed the angiographic and clinical outcomes of 5605 patients treated with DES in the setting of the ISAR-TEST 4 and ISAR-TEST 5 randomized control trials according to the presence or absence of stent overlap. The clinical endpoints assessed in this study were all-cause death, myocardial infarction (MI), target lesion revascularization (TLR), and definite or probable stent thrombosis at 10-years. We also compared rates of binary angiographic restenosis (BAR) at 6-8 months. RESULTS: At 10 years, all-cause mortality (Hazard ratios [HR] = 1.05 [0.95-1.16]; p = 0.348) did not differ between the stent overlap and no stent overlap groups. MI (8.4% vs. 5.2%; HR = 1.67 [1.35-2.07], p < 0.001) and TLR (23.7% vs. 16.3%; HR = 1.54 [1.36-1.74], p < 0.001) occurred more frequently in the stent overlap group. For MI, landmark analysis demonstrated that this increase in risk was primarily in the first 30 days post PCI. BAR at 6-8 months was also more frequent in the stent overlap group (16.0% vs. 10.3%; HR = 1.65 [1.41-1.92], p < 0.001). CONCLUSION: DES overlap is associated with an increased risk of adverse clinical events post PCI.

Angiographic performance of everolimus-eluting stents for the treatment of coronary in-stent restenosis in daily practice.

OBJECTIVES: The present study aims to analyze the angiographic anti-restenotic performance of durable polymer everolimus-eluting stents (EES) for the treatment of in-stent restenosis (ISR) in daily practice. BACKGROUND: Randomized data is available supporting the use of drug-coated balloons and drug-eluting stents for the treatment of ISR; however, additional real-world data including angiographic follow-up is needed. METHODS: Patients who underwent EES-implantation for the treatment of drug-eluting stent ISR and attended for a 6-8 months angiographic surveillance were analyzed. Off-line assessment of the angiograms was conducted at a central quantitative coronary angiographic core laboratory. RESULTS: A total of 426 patients with ISR were treated with EES and had undergone angiographic follow-up. The mean age was 66.8 ± 9.9 years and 27.5% suffered from diabetes. A total of 459 lesions were treated. The diameter stenosis decreased from 64.3 ± 19.1% (preprocedural) to 12.0 ± 6.4% (postprocedural). At 6-8 months angiographic follow-up, the in-segment diameter stenosis was 38.3 ± 21.7% and the in-stent late luminal loss was 0.54 ± 0.74 mm in the treated area analysis. The rate of recurrent binary restenosis was 25.7%. CONCLUSIONS: In the setting of ISR, the angiographic anti-restenotic efficacy of stenting with EES is comparable to that observed in randomized clinical trials and less favorable than its performance in patients undergoing stenting for de novo disease.

Multiscale modelling of charge transport in P3HT:DIPBI bulk heterojunction organic solar cells.

Charge transport properties of a P3HT:DIPBI bulk heterojunction solar cell are modelled by kinetic Monte Carlo simulations based on a morphology obtained from coarse-grained molecular dynamics. Different methods for calculating the hopping integrals entering the charge transfer rates are compared and calibrated for hole transport in amorphous P3HT. The influence of intermolecular and intramolecular charge transfer on the total charge carrier mobility and hence the power conversion efficiency is investigated in detail. An analysis of the most probable pathways with low resistance for hole transport is performed, establishing a connection between charge mobility and morphology.

Efficacy of drug-coated balloon angioplasty in early versus late occurring drug-eluting stent restenosis: A pooled analysis from the randomized ISAR DESIRE 3 and DESIRE 4 trials.

BACKGROUND: Whether there exist differences concerning clinical outcomes between patients presenting with early versus late DES-ISR undergoing treatment with drug-coated balloons (DCB) remains a scientific knowledge gap. METHODS: This is a pooled analysis including patients with DES-ISR assigned to treatment with DCB in the setting of the ISAR DESIRE 3 and 4 trials. Clinical outcomes were evaluated according to time of occurrence of ISR after DES implantation, in patients presenting with early (≤12 months) versus late DES-ISR (>12 months) undergoing treatment with DCB. The primary endpoint of this analysis was major adverse cardiac event (MACE), defined as the combined incidence of death, myocardial infarction and target lesion revascularization (TLR) at 12 months after DCB treatment. Secondary endpoints included the incidence of death, myocardial infarction, TLR and target lesion thrombosis at 12 months after DCB treatment. RESULTS: This analysis included 352 patients, 199 patients presented with early-ISR, 153 patients with late-ISR. Concerning the primary endpoint, patients with early-DES-ISR as compared those with late-DES-ISR showed significant higher risk (25.9% vs. 17.0%; p = .04). In a multivariate analysis including diabetic status, clinical presentation, previous coronary bypass graft and diameter stenosis after DCB-treatment, the adjusted hazard ratio showed significant higher risk for MACE of early-DES-ISR as compared to late-DES-ISR (HRadj = 1.8, [95% CI = 1.1-3.0], p = .02). CONCLUSION: Clinical outcome at 12 months after treatment of DES-ISR with DCB, showed significant higher clinical event rates in patients presenting with early DES restenosis, as compared with patients presenting with late DES restenosis.

Nearest Neighbor Decoding and Pilot-Aided Channel Estimation for Fading Channels.

We study the information rates of noncoherent, stationary, Gaussian, and multiple-input multiple-output (MIMO) flat-fading channels that are achievable with nearest neighbor decoding and pilot-aided channel estimation. In particular, we investigate the behavior of these achievable rates in the limit as the signal-to-noise ratio (SNR) tends to infinity by analyzing the capacity pre-log, which is defined as the limiting ratio of the capacity to the logarithm of the SNR as the SNR tends to infinity. We demonstrate that a scheme estimating the channel using pilot symbols and detecting the message using nearest neighbor decoding (while assuming that the channel estimation is perfect) essentially achieves the capacity pre-log of noncoherent multiple-input single-output flat-fading channels, and it essentially achieves the best so far known lower bound on the capacity pre-log of noncoherent MIMO flat-fading channels. Extending the analysis to fading multiple-access channels reveals interesting relationships between the number of antennas and Doppler bandwidth in the comparative performance of joint transmission and time division multiple-access.

Nanographene Imides Featuring Dual-Core Sixfold [5]Helicenes.

A novel kind of nanographene imide, namely pentaperylene decaimides (PPD) featuring dual-core sixfold [5]helicenes and ten imide groups, was efficiently obtained. Among the possible 28 stereoisomers, which include 14 pairs of enantiomers, only one pair of enantiomers was obtained selectively which could be separated by chiral HPLC. Single-crystal X-ray diffraction analyses revealed that it exhibits a D2 -symmetric "four-bladed propeller" conformation composed of conjoined double "three-bladed propeller", which is very stable and could not convert into other conformations even when heated up to 200 °C. Meanwhile, enantiomerically pure PPD also exhibits an excellent resistance to thermally induced racemization, which makes it a promising candidate for various applications in chiral material science.

Hexacene Diimides.

Acene imides are expected to possess smaller band gaps than homologous acenes while maintaining good solubility and stability. However, the design and synthesis of large acene imides are still a big challenge. Herein, we report a one-pot synthesis of hexacene diimides (HDI) by double aromatic annulation between zirconabenzocyclopentene and tetrabrominated naphthalene diimides. HDIs with branched alkyl chains exhibit very good solubility, stability, and much smaller band gaps than hexacene. Organic field-effect transistors (OFETs) based on HDI microribbons exhibit excellent ambipolar transport behavior with the highest electron mobility of 2.17 cm2 V-1 s-1 and hole mobility of 0.30 cm2 V-1 s-1 under ambient conditions.

Selective release of overexpressed recombinant proteins from E. coli cells facilitates one-step chromatographic purification of peptide-tagged green fluorescent protein variants.

The need for fast and convenient protein purification is enormous, not only on the industrial scale for the production of therapeutics but also in life science research. Most protein purification strategies require multiple steps, which are time consuming, cost and resource intensive. Selective release of the intracellular target product can considerably facilitate downstream processing by minimizing the HCP concentration before subsequent purification processes. Here, we present a simple method to selectively release soluble overexpressed proteins from E. coli with minimal laboratory equipment requirements. This method is based on the creation of pores in the cell envelope by a single freeze-thaw cycle. Proteins of various sizes were released by several 50 mM Tris pH 9.5 buffer washes with high yields. Consequently, the need for detergents and other additives were circumvented. Green fluorescent protein (GFP), was tagged with peptides of various charges and polarity. Releasing these GFP variants with our method enabled the successful one-step chromatographic purification on a quaternary amine resin despite the different isoelectric points of the target proteins. Up to 90% of the target protein elution peak during anion exchange chromatography was of >95% purity. This optimized process is more productive compared to multi-step purification procedures currently available in literature.

Conformation-dependent phosphorescence emission of individual mononuclear ruthenium-(ii)-bis-terpyridine complexes.

The potential of supramolecular transition metal coordination complexes to form robust, long-living, radiative charge transfer states makes this class of triplet state emitters ideal candidates for application as photosensitizes or in photonic devices. Antenna-enhanced phosphorescence experiments on single Ru2+-bis-terpyridine complexes incorporated into a thin PMMA film show that phosphorescence emission spectra can exhibit shifts depending on the local environment [J. F. Herrmann, P. S. Popp, A. Winter, U. S. Schubert and C. Höppener, ACS Photonics, 2016, 3, 1897-1906]. Here, we demonstrate that the environmentally altered spectral properties of individual dual-luminescent Ru2+-bis-terpyridine complexes in PMMA and acetonitrile can be reproduced by DFT-based vibrationally resolved Franck-Condon spectra, if the phosphorescent emission of different molecular conformations is taken into account. Furthermore, we demonstrate that the triplet emission of these complexes occurs from a metal-to-ligand charge transfer (MLCT) state.

Robust Signaling for Bursty Interference.

This paper studies a bursty interference channel, where the presence/absence of interference is modeled by a block-i.i.d. Bernoulli process that stays constant for a duration of T symbols (referred to as coherence block) and then changes independently to a new state. We consider both a quasi-static setup, where the interference state remains constant during the whole transmission of the codeword, and an ergodic setup, where a codeword spans several coherence blocks. For the quasi-static setup, we study the largest rate of a coding strategy that provides reliable communication at a basic rate and allows an increased (opportunistic) rate when there is no interference. For the ergodic setup, we study the largest achievable rate. We study how non-causal knowledge of the interference state, referred to as channel-state information (CSI), affects the achievable rates. We derive converse and achievability bounds for (i) local CSI at the receiver side only; (ii) local CSI at the transmitter and receiver side; and (iii) global CSI at all nodes. Our bounds allow us to identify when interference burstiness is beneficial and in which scenarios global CSI outperforms local CSI. The joint treatment of the quasi-static and ergodic setup further allows for a thorough comparison of these two setups.

Electron Accepting Units of the Diheme Cytochrome c TsdA, a Bifunctional Thiosulfate Dehydrogenase/Tetrathionate Reductase.

The enzymes of the thiosulfate dehydrogenase (TsdA) family are wide-spread diheme c-type cytochromes. Here, redox carriers were studied mediating the flow of electrons arising from thiosulfate oxidation into respiratory or photosynthetic electron chains. In a number of organisms, including Thiomonas intermedia and Sideroxydans lithotrophicus, the tsdA gene is immediately preceded by tsdB encoding for another diheme cytochrome. Spectrophotometric experiments in combination with enzymatic assays in solution showed that TsdB acts as an effective electron acceptor of TsdA in vitro when TsdA and TsdB originate from the same source organism. Although TsdA covers a range from -300 to +150 mV, TsdB is redox active between -100 and +300 mV, thus enabling electron transfer between these hemoproteins. The three-dimensional structure of the TsdB-TsdA fusion protein from the purple sulfur bacterium Marichromatium purpuratum was solved by X-ray crystallography to 2.75 Å resolution providing insights into internal electron transfer. In the oxidized state, this tetraheme cytochrome c contains three hemes with axial His/Met ligation, whereas heme 3 exhibits the His/Cys coordination typical for TsdA active sites. Interestingly, thiosulfate is covalently bound to Cys330 on heme 3. In several bacteria, including Allochromatium vinosum, TsdB is not present, precluding a general and essential role for electron flow. Both AvTsdA and the MpTsdBA fusion react efficiently in vitro with high potential iron-sulfur protein from A. vinosum (Em +350 mV). High potential iron-sulfur protein not only acts as direct electron donor to the reaction center in anoxygenic phototrophs but can also be involved in aerobic respiratory chains.

A Comparison of ML, WLSMV, and Bayesian Methods for Multilevel Structural Equation Models in Small Samples: A Simulation Study.

Multilevel structural equation models are increasingly applied in psychological research. With increasing model complexity, estimation becomes computationally demanding, and small sample sizes pose further challenges on estimation methods relying on asymptotic theory. Recent developments of Bayesian estimation techniques may help to overcome the shortcomings of classical estimation techniques. The use of potentially inaccurate prior information may, however, have detrimental effects, especially in small samples. The present Monte Carlo simulation study compares the statistical performance of classical estimation techniques with Bayesian estimation using different prior specifications for a two-level SEM with either continuous or ordinal indicators. Using two software programs (Mplus and Stan), differential effects of between- and within-level sample sizes on estimation accuracy were investigated. Moreover, it was tested to which extent inaccurate priors may have detrimental effects on parameter estimates in categorical indicator models. For continuous indicators, Bayesian estimation did not show performance advantages over ML. For categorical indicators, Bayesian estimation outperformed WLSMV solely in case of strongly informative accurate priors. Weakly informative inaccurate priors did not deteriorate performance of the Bayesian approach, while strong informative inaccurate priors led to severely biased estimates even with large sample sizes. With diffuse priors, Stan yielded better results than Mplus in terms of parameter estimates.

A Cross-Classified CFA-MTMM Model for Structurally Different and Nonindependent Interchangeable Methods.

Multirater (multimethod, multisource) studies are increasingly applied in psychology. Eid and colleagues (2008) proposed a multilevel confirmatory factor model for multitrait-multimethod (MTMM) data combining structurally different and multiple independent interchangeable methods (raters). In many studies, however, different interchangeable raters (e.g., peers, subordinates) are asked to rate different targets (students, supervisors), leading to violations of the independence assumption and to cross-classified data structures. In the present work, we extend the ML-CFA-MTMM model by Eid and colleagues (2008) to cross-classified multirater designs. The new C4 model (Cross-Classified CTC[M-1] Combination of Methods) accounts for nonindependent interchangeable raters and enables researchers to explicitly model the interaction between targets and raters as a latent variable. Using a real data application, it is shown how credibility intervals of model parameters and different variance components can be obtained using Bayesian estimation techniques.

Thiosulfate transfer mediated by DsrE/TusA homologs from acidothermophilic sulfur-oxidizing archaeon Metallosphaera cuprina.

Conserved clusters of genes encoding DsrE and TusA homologs occur in many archaeal and bacterial sulfur oxidizers. TusA has a well documented function as a sulfurtransferase in tRNA modification and molybdenum cofactor biosynthesis in Escherichia coli, and DsrE is an active site subunit of the DsrEFH complex that is essential for sulfur trafficking in the phototrophic sulfur-oxidizing Allochromatium vinosum. In the acidothermophilic sulfur (S(0))- and tetrathionate (S4O6(2-))-oxidizing Metallosphaera cuprina Ar-4, a dsrE3A-dsrE2B-tusA arrangement is situated immediately between genes encoding dihydrolipoamide dehydrogenase and a heterodisulfide reductase-like complex. In this study, the biochemical features and sulfur transferring abilities of the DsrE2B, DsrE3A, and TusA proteins were investigated. DsrE3A and TusA proved to react with tetrathionate but not with NaSH, glutathione persulfide, polysulfide, thiosulfate, or sulfite. The products were identified as protein-Cys-S-thiosulfonates. DsrE3A was also able to cleave the thiosulfate group from TusA-Cys(18)-S-thiosulfonate. DsrE2B did not react with any of the sulfur compounds tested. DsrE3A and TusA interacted physically with each other and formed a heterocomplex. The cysteine residue (Cys(18)) of TusA is crucial for this interaction. The single cysteine mutants DsrE3A-C(93)S and DsrE3A-C(101)S retained the ability to transfer the thiosulfonate group to TusA. TusA-C(18)S neither reacted with tetrathionate nor was it loaded with thiosulfate with DsrE3A-Cys-S-thiosulfonate as the donor. The transfer of thiosulfate, mediated by a DsrE-like protein and TusA, is unprecedented not only in M. cuprina but also in other sulfur-oxidizing prokaryotes. The results of this study provide new knowledge on oxidative microbial sulfur metabolism.

Distinguishing state variability from trait change in longitudinal data: the role of measurement (non)invariance in latent state-trait analyses.

Researchers analyzing longitudinal data often want to find out whether the process they study is characterized by (1) short-term state variability, (2) long-term trait change, or (3) a combination of state variability and trait change. Classical latent state-trait (LST) models are designed to measure reversible state variability around a fixed set-point or trait, whereas latent growth curve (LGC) models focus on long-lasting and often irreversible trait changes. In the present article, we contrast LST and LGC models from the perspective of measurement invariance testing. We show that establishing a pure state-variability process requires (1) the inclusion of a mean structure and (2) establishing strong factorial invariance in LST analyses. Analytical derivations and simulations demonstrate that LST models with noninvariant parameters can mask the fact that a trait-change or hybrid process has generated the data. Furthermore, the inappropriate application of LST models to trait change or hybrid data can lead to bias in the estimates of consistency and occasion specificity, which are typically of key interest in LST analyses. Four tips for the proper application of LST models are provided.

Scanning-tunneling-spectroscopy-directed design of tailored deep-blue emitters.

Frontier molecular orbitals can be visualized and selectively set to achieve blue phosphorescent metal complexes. For this purpose, the HOMOs and LUMOs of tridentate Pt(II) complexes were measured using scanning tunneling microscopy and spectroscopy. The introduction of electron-accepting or -donating moieties enables independent tuning of the frontier orbital energies, and the measured HOMO-LUMO gaps are reproduced by DFT calculations. The energy gaps correlate with the measured and the calculated energies of the emissive triplet states and the experimental luminescence wavelengths. This synergetic interplay between synthesis, microscopy, and spectroscopy enabled the design and realization of a deep-blue triplet emitter. Finding and tuning the electronic "set screws" at molecular level constitutes a useful experimental method towards an in-depth understanding and rational design of optoelectronic materials with tailored excited state energies and defined frontier-orbital properties.

The Implicit Association Test and its difficulty(ies): Introducing the test difficulty concept to increase the true-score variance and, consequently, the predictive power of implicit association tests.

We introduce the test difficulty concept from classical test theory to tackle the issue of low predictive power of implicit association tests (IATs). Following classical test theory, we argue that IATs of moderate difficulty (defined as mean IAT scores of zero) have more predictive power than IATs of extreme difficulties (defined as mean IAT scores deviating strongly from zero). Furthermore, we assume this relationship to be mediated by the true-score variance in IAT scores, with moderate difficulty resulting in more true-score variance. To test our hypotheses, we used nonexperimental (Studies 1 and 2) and experimental designs (Study 3). In Studies 1 and 2, we compared IATs of different test difficulties with regard to their ability to predict direct attitude measures, drawing on the Attitudes, Identities, and Individual Differences study. In Study 1, a subset of 95 attitude IATs (n = 127,259) was analyzed using multilevel structural equation models. As expected, IAT test difficulty strongly moderated the predictive power of IATs, and this effect was mediated by IAT true-score variance. In Study 2, we replicated the results with the same analyses but a different subset of 95 identity IATs (n = 43,745). In Study 3, we experimentally manipulated the IAT test difficulty. In total, three IATs (n = 480) were analyzed using multigroup structural equation models. Again, the IAT closer to moderate difficulty had more true-score variance and predictive power than the IATs of extreme difficulty. Accordingly, for correlational research, we recommend developing moderately difficult IATs to maximize IAT true-score variance and provide suggestions on how to achieve that. (PsycInfo Database Record (c) 2024 APA, all rights reserved).