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We present a new benchmark set consisting of 16 large non-covalently bound systems (LNCI16) ranging from 380 up to 1988 atoms and featuring diverse interaction motives. Gas-phase interaction energies are calculated with various composite DFT, semi-empirical quantum mechanical (SQM), and force field (FF) methods and are evaluated using accurate DFT reference values. Of the employed QM methods, PBEh-3c proves to be the most robust for large systems with a relative mean absolute deviation (relMAD) of 8.5% with respect to the reference interaction energies. r2SCAN-3c yields an even smaller relMAD, at least for the subset of complexes for which the calculation could be converged, but is less robust for systems with smaller HOMO–LUMO gaps. The inclusion of Fock-exchange is therefore important for the description of very large non-covalent interaction (NCI) complexes in the gas phase. GFN2-xTB was found to be the best performer of the SQM methods with an excellent result of only 11.1% deviation. From the assessed force fields, GFN-FF and GAFF achieve the best accuracy. Considering their low computational costs, both can be recommended for routine calculations of very large NCI complexes, with GFN-FF being clearly superior in terms of general applicability. Hence, GFN-FF may be routinely applied in supramolecular synthesis planning.1 Introduction2 The LNCI16 Benchmark Set3 Computational Details4 Generation of Reference Values5 Results and Discussion6 Conclusions

We present the first benchmark set focusing on the conformational energies of highly flexible, long n-alkane chains, termed ACONFL. Unbranched alkanes are ubiquitous building blocks in nature, so the goal is to be able to calculate their properties most accurately to improve the modeling of, e.g, complex (biological) systems. Very accurate DLPNO-CCSD(T1)/CBS reference values are provided, which allow for a statistical meaningful evaluation of even the best available density functional methods. The performance of established and modern (dispersion corrected) density functionals is comprehensively assessed. The recently introduced r²SCAN-V functional shows excellent performance, similar to efficient composite DFT methods like B97-3c and r²SCAN-3c, which provide an even better cost-accuracy ratio, while almost reaching the accuracy of much more computationally demanding hybrid or double hybrid functionals with large QZ AO basis sets. In addition, we investigated the performance of common wavefunction methods, where MP2/CBS surprisingly performs worse compared to simple D4 dispersion corrected Hartree–Fock. Furthermore, we investigate the performance of several semiempirical and force field methods, which are commonly used for the generation of conformational ensembles in multilevel workflows or in large scale molecular dynamics studies. Outstanding performance is obtained by the recently introduced general force field, GFN-FF, while other commonly applied methods like the universal force field yield large errors. We recommend the ACONFL as a helpful benchmark set for parameterization of new semiempirical or force field methods and machine learning potentials as well as a meaningful validation set for newly developed DFT or dispersion methods.

An automated and broadly applicable workflow for the description of solvation effects in an explicit manner is introduced. This method, termed quantum cluster growth (QCG), is based on the semiempirical GFN2-xTB/GFN-FF methods, enabling efficient geometry optimizations and MD simulations. Fast structure generation is provided using the intermolecular force field xTB-IFF. Additionally, the approach uses an efficient implicit solvation model for the electrostatic embedding of the growing clusters. The novel QCG procedure presents a robust cluster generation tool for subsequent application of higher-level (e.g., DFT) methods to study solvation effects on molecular geometries explicitly or to average spectroscopic properties over cluster ensembles. Furthermore, the computation of the solvation free energy with a supermolecular approach can be carried out with QCG. The underlying growing process is physically motivated by computing the leading-order solute-solvent interactions first and can account for conformational and chemical changes due to solvation for low-energy barrier processes. The conformational space is explored with the NCI-MTD algorithm as implemented in the CREST program, using a combination of metadynamics and MD simulations. QCG with GFN2-xTB yields realistic solution geometries and reasonable solvation free energies for various systems without introducing many empirical parameters. Computed IR spectra of some solutes with QCG show a better match to the experimental data compared to well-established implicit solvation models.

Background: Hand eczema (HE) is a common skin disease characterized by itch, pain and visible skin changes such as fissures, erythema and vesicles. It is not yet clear which outcome domains are most important for patients. The Hand Eczema Core Outcome Set (HECOS) initiative is developing a consented set of core domains and suitable measurement instruments for the future application in all HE trials. This includes an online Delphi survey about core domains, which requires a ‘Long List’ of all domains that might be important to measure. Objectives: To compile a ‘Long List’ of candidate outcome domains for therapeutic HE trials with suggestions from patients and experts. Methods: First, 60 patients with chronic HE were interviewed at seven study sites in Croatia, Denmark, Germany, the Netherlands and Spain. Patients were asked about domains that were important from their perspectives. Second, 185 HE experts were invited by email to complete an online survey. With an open question, they were asked to suggest up to six domains. Results: Suggestions were provided by 58 patients and 82 experts. Most patients and experts suggested to measure the domains ‘signs’, ‘symptoms’ and ‘HE-related quality of life’. Specifically, >25% of patients said that less itch, pain or fissures indicated a successful treatment. Among experts, >25% suggested ‘itch’ and ‘ability to work’ as core sub-domains. Further outcomes from the domains ‘HE control over time’, ‘patient-reported treatment experience’ and ‘skin barrier function’ were mentioned. Conclusion: ‘Itch’ was rated high among patients with HE and professional HE experts. While patients emphasized fissures as important, experts underlined the ability to work. This investigation allowed us to define a ‘Long List’ of 7 candidate outcome domains with 58 sub-domains. From this list, a panel of stakeholders will select core domains during an online Delphi survey.

Zusammenfassung Hintergrund Berufsbedingte Hauterkrankungen treten in vielen Berufen auf. Häufig handelt es sich um irritative und/oder allergische Handekzeme. Zu den häufigsten betroffenen Berufsgruppen zählen z. B. Pflegekräfte und Metallarbeiter*innen. Hinsichtlich soziodemografischer Merkmale (Alter, Berufe, Geschlecht) ist das Patientenklientel insgesamt sehr heterogen. Individualpräventive ambulante und stationäre Maßnahmen zielen u. a. darauf ab, das Selbstmanagement mit der Erkrankung zu verbessern (z. B. Veränderung des Hautschutzverhaltens) und ein erkrankungsbedingtes Ausscheiden aus dem Beruf zu verhindern. Subjektive Krankheitstheorien spielen bei der Erreichung dieser Ziele eine wichtige Rolle, so dass es das Ziel der Studie war, diese subjektiven Theorien unter besonderer Beachtung soziodemografischer Merkmale zu erfassen und zu analysieren. Methode Es wurden 36 leitfadengestützte qualitative Interviews mit Patient*innen einer stationären Individualpräventionsmaßnahme geführt. Die Auswertung erfolgte mittels inhaltlich strukturierender qualitativer Inhaltsanalyse. Hauptkategorien wurden deduktiv anhand des theoretischen Rahmens (Common-Sense-Modell) gebildet, Subkategorien anhand des Materials (induktiv). Ergebnisse Interviewtranskripte von 35 Patient*innen wurden analysiert (Geschlecht: weiblich = 18, männlich = 17/Alter: minimal: 22 Jahre, maximal: 63 Jahre). Dabei ließen sich alle Dimensionen des Rahmenmodells mit verschiedenen Subkategorien abbilden. Die vermuteten bzw. wahrgenommenen Ursachen waren überwiegend komplex. Hinsichtlich der Altersgruppen und Berufe konnten teilweise Unterschiede festgestellt werden. So waren z. B. Aussagen, die auf eine höhere Selbstwirksamkeit in Bezug auf die Kontrollierbarkeit des Handekzems hindeuteten eher bei interviewten Pflegekräften zu finden, als bei den Befragten der Metallberufe. Schlussfolgerungen Die Wahrnehmung komplexer Ursachen spiegelt die oftmals multifaktorielle Krankheitsentstehung wider (z. B. irritative Handekzeme bei atopischer Disposition). Die z. T. vorgefundenen Unterschiede zwischen Berufs- und Altersgruppen verdeutlichen, dass involvierte Berufsgruppen (z. B. Ärzt*innen, Therapeut*innen) bei der Berücksichtigung der subjektiven Krankheitsvorstellungen auch ein Zusammenspiel mit soziodemografischen Aspekten erwägen sollten.

We introduce a set of 13 supramolecular complexes featuring diverse non-covalent interactions with heavy main group elements (Zn, As, Se, Te, Br, I), high charges (-2 up to +4), and large systems with up to 266 atoms (HS13L). The experimental Gibbs free energies of association cover the typical range (-1.9 to -9.2 kcal mol

A new composite density functional theory (DFT) method is presented. It is based on ωB97X-V as one of the best-performing density functionals for the GMTKN55 thermochemistry database and completes the family of “3c” methods toward range-separated hybrid DFT. This method is consistently available for all elements up to Rn (Z = 1–86). Its further key ingredients are a polarized valence double- ζ (vDZP) Gaussian basis set, which was fully optimized in molecular DFT calculations, in combination with large-core effective core potentials and a specially adapted D4 dispersion correction. Unlike most existing double- ζ atomic orbital sets, vDZP shows only small basis set superposition errors (BSSEs) and can compete with standard sets of triple- ζ quality. Small residual BSSE effects are efficiently absorbed by the D4 damping scheme, which overall eliminates the need for an explicit treatment or empirical corrections for BSSE. Thorough tests on a variety of thermochemistry benchmark sets show that the new composite method, dubbed ωB97X-3c, is on par with or even outperforms standard hybrid DFT methods in a quadruple-zeta basis set at a small fraction of the computational cost. Particular strengths of this method are the description of non-covalent interactions and barrier heights, for which it is among the best-performing density functionals overall.

—Collaborative robots (cobots) have seen widespread adoption in industrial applications over the last decade. Cobots can be placed outside protective cages and are generally regarded as much more intuitive and easy to program compared to larger classical industrial robots. However, despite the cobots’ widespread adoption, their collaborative potential and opportunity to aid flexible production processes seem hindered by a lack of training and understanding from shopfloor workers. Researchers have focused on technical solutions, which allow novice robot users to more easily train the collaborative robots. However, most of this work have yet to leave research labs. Therefore, training methods are needed with the goal of transferring skills and knowledge onto shop floor workers about how to program collaborative robots. We identify general basic knowledge and skills that a novice must master to program a collaborative robot. We present how to structure and facilitate cobot training based on cognitive apprenticeship and test the training framework on a total of 20 participants using a UR10e and UR3e robot. We considered two conditions: adaptive and self-regulated training. We find that the facilitation was effective in transferring knowledge and skills to novices, however, found no conclusive difference between the adaptive or self-regulated approach. Note to Practitioners— This paper was motivated by the fact that adoption of smaller, so-called collaborative robots is increasing within manufacturing but the potential for a single robot to be used flexibly in multiple places of a production seems unfulfilled. If more unskilled workers understood the collaborative robots and received structured training, they would be capable of programming the robots independently. This could change the current landscape of stationary collaborative robots towards more flexible robot use and thereby increase companies’ internal overall equipment efficiency and competences. To this end, we identify general skills and knowledge for programming a collaborative robot, which help increase transparency of what novices need to know. We show how such knowledge and skills may be facilitated in a structured training framework, which effectively transfers necessary programming knowledge and skills to novices. This framework may be applied to a wider scope of knowledge and skills as the learner progresses. The skills and knowledge that we identify are general across robot platforms, however, collaborative robot interfaces differ. Therefore, a practical limitation to the approach include the need for a knowledgeable person on the specific collaborative robot in question in order to create training material in areas specific to that model. Though, with our list of identified skills, it provides an easier starting point. We show that relatively few skills and knowledge areas can enhance a novice’s programming capability.

We present monometallic H2 production electrocatalysts containing electron-rich triamine-cyclopentadienyl (Cp) ligands coordinated to iron. After selective CO extrusion from the iron tricarbonyl precursors, electrocatalysis is observed via cyclic voltammetry in the presence of an exogenous acid. Contrary to the fact that amines in the secondary coordination sphere are often protonated during electrocatalysis, comprehensive quantum-chemical calculations indicate that the amines likely do not function as proton relays; instead, endo-Cp ring protonation is most favorable after 1e- reduction. This unusual mechanistic pathway emphasizes the need to consider a broad domain of H+/e- addition products by synergistically combining experimental and theoretical resources.

Due to the principle lack of systematic improvement possibilities of density functional theory, careful assessment of the performance of density functional approximations (DFAs) on well-designed benchmark sets, for example, for reaction energies and barrier heights, is crucial. While main-group chemistry is well covered by several available sets, benchmark data for transition metal chemistry is sparse. This is especially the case for larger, chemically relevant molecules. Addressing this issue, we recently introduced the MOR41 benchmark which covers chemically relevant reactions of closed-shell complexes. In this work, we extend these efforts to single-reference open-shell systems and introduce the "reactions of open-shell single-reference transition metal complexes" (ROST61) benchmark set. ROST61 includes accurate coupled-cluster reference values for 61 reaction energies with a mean reaction energy of -42.8 kcal mol-1. Complexes with 13-93 atoms covering 20 d-block elements are included, but due to the restriction to single-reference open-shell systems, important elements such as iron or platinum could not be taken into account, or only to a small extent. We assess the performance of 31 DFAs in combination with three London dispersion (LD) correction schemes. Further, DFT-based composite methods, MP2, and a few semiempirical quantum chemical methods are evaluated. Consistent with the results for the MOR41 closed-shell benchmark, we find that the ordering of DFAs according to Jacob's ladder is preserved and that adding an LD correction is crucial, clearly improving almost all tested methods. The recently introduced r2SCAN-3c composite method stands out with a remarkable mean absolute deviation (MAD) of only 2.9 kcal mol-1, which is surpassed only by hybrid DFAs with low amounts of Fock exchange (e.g., 2.3 kcal mol-1 for TPSS0-D4/def2-QZVPP) and double-hybrid (DH) DFAs but at a significantly higher computational cost. The lowest MAD of only 1.6 kcal mol-1 is obtained with the DH DFA PWPB95-D4 in the def2-QZVPP basis set approaching the estimated accuracy of the reference method. Overall, the ROST61 set adds important reference data to a sparsely sampled but practically relevant area of chemistry. At this point, it provides valuable orientation for the application and development of new DFAs and electronic structure methods in general.

The adiabatic energy gap between the lowest singlet and triplet excited states ΔEST is a central property of thermally activated delayed fluorescence (TADF) emitters. Since these states are dominated by a charge-transfer character, causing strong orbital-relaxation and environmental effects, an accurate prediction of ΔEST is very challenging, even with modern quantum-chemical excited-state methods. Addressing this major challenge, we present an approach that combines spin-unrestricted (UKS) and restricted open-shell Kohn-Sham (ROKS) self-consistent field calculations with a polarizable-continuum model and range-separated hybrid functionals. Tests on a new representative benchmark set of 27 TADF emitters with accurately known ΔEST values termed STGABS27 reveal a robust and unprecedented performance with a mean absolute deviation of only 0.025 eV (∼0.5 kcal/mol) and few deviations greater than 0.05 eV (∼1 kcal/mol), even in electronically challenging cases. Requiring only two geometry optimizations per molecule at the ROKS/UKS level in a compact double-ζ basis, the approach is computationally efficient and can routinely be applied to molecules with more than 100 atoms.

Fullerenes and diamondoids are at the core of nanoscience. Comparable monodisperse silicon analogues are scarce. Herein, we report the synthesis of the parent siladodecahedrane, which represents the largest Platonic solid. It shares its pattern of pentagonal faces with the smallest fullerene, C20, and its saturated, H-terminated skeleton with diamondoids. Similar to endofullerenes, the silicon cage encapsulates a chloride ion ([Cl@Si20H20]-); similar to diamondoids, its Si-H termini offer a wealth of opportunities for further functionalization. Mere treatment with chloromethanes leads to the perchlorinated cluster [Cl@Si20Cl20]-. Both compounds were characterized by mass spectrometry, X-ray crystallography, NMR spectroscopy, and quantum-chemical calculations. The experimentally determined 35Cl resonances of the endohedral chloride ions are particularly diagnostic to probe the Cl- → Si20 interaction strength as a function of the different surface substituents, as we have proven by high-level computational analyses.

Mitzel and co‐workers recently presented an intriguing molecule displaying a tellurium–nitrogen interaction. Structural data obtained in the solid and in gas phase indicated a large increase of the Te–N equilibrium distance r e from 2.64 to 2.92 Å, respectively. Although some DFT calculations appear to support the large r e in gas phase, we argue that the lions share of the increase is due to an incomplete description of finite‐temperature effects in the back‐corrected experimental data. This hypothesis is based on high‐level coupled‐cluster (CC) and periodic DFT calculations, which consistently point towards a much smaller r e in the isolated molecule. Further support comes through MD simulations with a tuned GFN2‐xTB Hamiltonian: Calibrated against a CC reference, these show a six‐times larger influence of temperature than with the originally used GFN1‐xTB. Taking this into account, the back‐corrected r e in gas phase becomes 2.67±0.08 Å, in good agreement with high‐level CC theory and most DFT methods., An intriguing molecule displaying a tellurium–nitrogen interaction has been recently presented. Structural data indicated a large increase of the Te−N equilibrium distance from 2.64 Å in the solid to 2.92 Å in gas phase. We show that the lions share of the increase is due to an incomplete description of finite‐temperature effects in the back‐corrected experimental data.

Studying the redox behavior of Earth-abundant metal complexes and understanding their reactivity under reducing conditions is of fundamental importance for activating small molecules. We present the electrochemical behavior and reactivity of amine-functionalized indenylmanganese(I) complexes that form the piano-stool complexes MnI(CO)3(IndR) (R = pyrrolidinyl, piperazinyl), which exhibit two cathodic redox waves via cyclic voltammetry (CV). Electrochemical, spectroscopic, and structural comparisons of these complexes with the undecorated indenyl species reveal that the pyrrolidine-substituted tricarbonylmanganese complex MnIndPyrr is the most electron rich due to favorable π donor effects from the amine into the ring system. These results are also strongly supported by DFT computations. Although CV studies show clean redox behavior, reaction outcomes in the presence of common chemical reductants are strongly dependent on the reagents used. Reduction of MnIndPyrr with KC8 in the presence of the encapsulating agent 2,2,2-Crypt forms a rare Mn(0) metalloradical, [K(2,2,2-Crypt)][MnIndPyrr] which was characterized by single crystal X-ray diffraction, EPR spectroscopy, IR spectroscopy, and DFT calculations. Attempts to isolate a doubly reduced Mn(-I) adduct in the presence of 18-crown-6 resulted in indenide anion loss to generate a mixed-valence Mn(-I)/Mn(I) adduct where the two metal centers bind to a single indenyl moiety. This study emphasizes the dramatic differences between observing redox-reversible behavior on the electroanalytical scale and performing preparative scale reduction reactions with alkali metals and encapsulating agent, as these reagents have a profound impact on the reaction outcome.

How do criminal groups organize, operate, and govern in Denmark? We argue that organized crime groups face governance challenges in the form of principal-agent problems and transaction costs. Based on interviews with law enforcement officers, former gang members, and prisoners, we provide evidence for how people involved in crime respond to these organizational dilemmas. We find that the more severe the principal-agent problem, the more gangs vet possible members during recruitment. We also find that as transaction costs rise, people who are engaged in illicit activities that are more complicated will rely more on internal structure and centralization. Our findings support existing rational choice theories of criminal organizations.

The noncovalent interactions between azides and oxygen‐containing moieties are investigated through a computational study based on experimental findings. The targeted synthesis of organic compounds with close intramolecular azide–oxygen contacts yielded six new representatives, for which X‐ray structures were determined. Two of those compounds were investigated with respect to their potential conformations in the gas phase and a possible significantly shorter azide–oxygen contact. Furthermore, a set of 44 high‐quality, gas‐phase computational model systems with intermolecular azide–pnictogen (N, P, As, Sb), –chalcogen (O, S, Se, Te), and –halogen (F, Cl, Br, I) contacts are compiled and investigated through semiempirical quantum mechanical methods, density functional approximations, and wave function theory. A local energy decomposition (LED) analysis is applied to study the nature of the noncovalent interaction. The special role of electrostatic and London dispersion interactions is discussed in detail. London dispersion is identified as a dominant factor of the azide–donor interaction with mean London dispersion energy‐interaction energy ratios of 1.3. Electrostatic contributions enhance the azide–donor coordination motif. The association energies range from −1.00 to −5.5 kcal mol−1., The interactions that bind: The noncovalent interactions between azides and oxygen‐containing moieties are investigated through a computational study based on experimental findings. A set of 44 high‐quality, gas‐phase computational model systems with intermolecular azide–pnictogen, –chalcogen, and –halogen contacts are compiled and investigated through semiempirical quantum mechanical methods, density functional approximations, and wave function theory.

The H• transfer rate constants for a series of group 6 molybdenum and tungsten pyrazolyl borate complexes are described. The rate constants for these complexes were found to span a range over 1 magnitude. Analysis of the H• transfer rate constants suggests that a combination of steric, electronic, and enthalpic factors are important in these reactions. Further analysis of the components suggests that the generated 17 e– radicals of these complexes are less electrophilic than the more commonly used CpCr(CO)3H complexes. General implications for H• transfer reactions are discussed.

Protective gloves are an elementary component of personal protective equipment in many occupations and are intended to protect the hands from various hazards (e.g., wetness, chemicals, mechanical forces, or thermal stress). This is particularly important when other occupational safety measures (e.g., technical-organizational measures) cannot be implemented or are insufficient. However, it is not uncommon for protective gloves themselves to become a problem, as some of their ingredients (e.g., rubber accelerators) can cause allergic reactions. Accelerators in rubber gloves include thiurams, dithiocarbamates, thiazoles, guanidines, and thioureas. If no alternative means of protection are available, this may even result in abandoning the profession. This article is about rubber accelerators, which are often contained in protective gloves made of different rubber materials (e.g., natural rubber (latex) and nitrile rubber) and may cause delayed-type allergies, as well as related challenges, problems, and solutions for occupational skin protection.

Kontaktallergien durch die Inhaltsstoffe von Epoxidharzsystemen sind seit über 20 Jahren in vielen Branchen eine der häufigsten berufsbedingten allergischen Hauterkrankungen. Der Arbeitskreis Epoxidharze hat daher seit seiner Gründung im Jahr 2007 als branchenübergreifende, europäische Initiative unterschiedliche Strategien entwickelt, um das Erkrankungsrisiko zu verringern. Sie zielen einerseits auf die Verbesserung der Ausbildung und Arbeitshygiene ab, andererseits auf die medizinische und toxikologische Forschung zur Identifizierung von allergisierenden Epoxidharzkomponenten sowie die Förderung von Alternativen mit geringerem sensibilisierenden Potenzial.

Conformational energies are an important chemical property for which a performance assessment of theoretical methods is mandatory. Existing benchmark sets are often limited to biochemical or main group element containing molecules, while organometallic systems are generally less studied. A key problem herein is to routinely generate conformers for these molecules due to their complexity and manifold of possible coordination patterns. In this study we used our recently published CREST protocol [Pracht et al., Phys. Chem. Chem. Phys., 2020, 22, 7169-7192] to generate conformer ensembles for a variety of 40 challenging transition metal containing molecules, which were then used to form a comprehensive conformational energy benchmark set termed TMCONF40. Several low-cost semiempirical, density functional theory (DFT) and force-field methods were compared to high level DLPNO-CCSD(T1) and double-hybrid DFT reference values. Close attention was paid to the energetic ordering of the conformers in the statistical evaluation. With respect to the double-hybrid references, both tested low-cost composite DFT methods produce high Pearson correlation coefficients of rp,mean,B97-3c//B97-3c = 0.922 and rp,mean,PBEh-3c//B97-3c = 0.890, with mean absolute deviations close to or below 1 kcal mol-1. This good performance also holds for a comparison to DLPNO-CCSD(T1) reference energies for a smaller subset termed TMCONF5. Based on DFT geometries, the GFNn-xTB methods yield reasonable Pearson correlation coefficients of rp,mean,GFN1-xTB//B97-3c = 0.617 (MADmean = 2.15 kcal mol-1) and rp,mean,GFN2-xTB//B97-3c = 0.567 (MADmean = 2.68 kcal mol-1), outperforming the widely used PMx methods on the TMCONF40 test set. Employing the low-cost composite DFT method B97-3c on GFN2-xTB geometries yields an slightly improved correlation of rp,mean,B97-3c//GFN2-xTB = 0.632. Furthermore, for 68% of the investigated complexes at least one low-energy conformer was found that is more stable than the respective crystal structure conformation, which signals the importance of conformational studies. General recommendations for the application of the CREST protocol and DFT methods for transition metal conformational energies are given.

Zusammenfassung Hintergrund Aufgrund ihrer technischen Eigenschaften werden Epoxidharze (Kunstharze) in vielen Berufen eingesetzt. Wegen ihres hohen Allergiepotenzials ist ein adäquates Hautschutzverhalten bei der Verarbeitung von hoher Bedeutung. Lehrkräfte an Berufsschulen können als Multiplikator*innen fungieren, damit Auszubildende bereits beim Erlernen eines Berufs die notwendigen Kenntnisse und Fertigkeiten erwerben und Hautschutz als selbstverständlichen Teil der Arbeitsroutinen internalisieren. Ziel der Arbeit Das konzeptionelle Projekt „EpoxSafe@School“ zielte darauf ab, Unterrichtsmaterialien zur Prävention epoxidharzbedingter Hauterkrankungen für die Berufsschule zu entwickeln, die auf dem wissenschaftlichen Erkenntnisstand basieren und an die Bedürfnisse von Lehrkräften angepasst sind. Material und Methoden Im Projektverlauf wurden die Anforderungen und Bedürfnisse von Lehrkräften an durch fremde Personen erstellte Unterrichtsmaterialien im Rahmen von zwei Fokusgruppendiskussionen erhoben. Die Ergebnisse wurden bei der didaktischen Konstruktion der Materialien berücksichtigt. Ferner erfolgten Recherchen (z. B. zur Evidenz, zum Setting Berufsschule) als Grundlage für die Entwicklung der Materialien. Ergebnisse und Diskussion Von den Lehrkräften wurden folgende Anforderungen an fremd erstellte Materialien formuliert: methodische Variabilität, Flexibilität und Veränderbarkeit, Exemplarität, Alltagsnähe, Berufsbezug sowie die Berücksichtigung des curricularen Rahmens. Die vor diesem Hintergrund entwickelten Materialien (z. B. Schüler‑/Lehrertexte, Arbeitsblätter, Experimente) sind seit Projektende frei verfügbar. Ausblickend sind Untersuchungen zur Bewertung der Materialien durch Lehrkräfte und Auszubildende sowie zum Praxiseinsatz und deren möglicher Effekte empfehlenswert.

Nowadays, many chemical investigations can be supported theoretically by routine molecular structure calculations, conformer ensembles, reaction energies, barrier heights, and predicted spectroscopic properties. Such standard computational chemistry applications are most often conducted with density functional theory (DFT) and atom-centered atomic orbital basis sets implemented in many standard quantum chemistry software packages. This work aims to provide general guidance on the various technical and methodological aspects of DFT calculations for molecular systems, and how to achieve an optimal balance between accuracy, robustness, and computational efficiency through multi-level approaches. The main points discussed are the density functional, the atomic orbital basis sets, and the computational protocol to describe and predict experimental behavior properly. This is done in three main parts: Firstly, in the form of a step-by-step decision tree to guide the overall computational approach depending on the problem; secondly, using a recommendation matrix that addresses the most critical aspects regarding the functional and basis set depending on the computational task at hand (structure optimization, reaction energy calculations, etc.); and thirdly, by applying all steps to some representative examples to illustrate the recommended protocols and effect of methodological choices.

The absolute molecular entropy is a fundamental quantity for the accurate description of thermodynamic properties. For non-rigid molecules, a substantial part of the entropy can be attributed to a conformational contribution. Systems and properties where this is relevant

The structural properties of μ

Existing semiempirical molecular orbital methods suffer from the usually minimal atomic-orbital (AO) basis set used to simplify the calculations. Here, a completely new and consistently parameterized tight-binding electronic structure Hamiltonian evaluated in a deeply contracted, properly polarized valence double-zeta basis set (vDZP) is described. The inner-shell electrons are accounted for by standard, large-core effective potentials and approximations to them. The primary target of this so-called density matrix tight-binding method is to reproduce the one-particle density matrix P of a molecular ωB97X-V range-separated hybrid density functional theory (DFT) calculation in exactly the same basis set. Additional properties considered are orbital energies, dipole polarizabilities and dipole moments, and dipole polarizability derivatives. The key features of the method are as follows: (a) it is non-self-consistent with an overall fixed number of only three required matrix diagonalizations; (b) only AO overlap integrals are needed to construct the effective Hamiltonian matrix; (c) new P-dependent terms emulating non-local exchange are included; and (d) only element-specific empirical parameters (about 50 per element) need to be determined. The method globally achieves a high accuracy for the target properties at a speedup compared to the ωB97X-V/vDZP reference of about 3–4 orders of magnitude. It performs robustly for difficult transition metal complexes, for highly charged or zwitterionic systems, and for chemically unusual bonding situations, indicating a generally robust approximation of the (self-consistent) Kohn–Sham potential. As an example application, the vibrational Raman spectrum of an entire protein with 327 atoms with respect to the DFT reference calculation is shown. This method may be used out-of-the-box to generate molecular/atomic features for machine learning applications or as the basis for accurate high-speed DFT methods.

We present monometallic H

Hydrogen atom (H•) donors generated from H2 facilitate the atom efficient reduction of small molecule substrates. However, generating H• donors with X–H bond dissociation free energies (BDFEs) belo...

Fullerenes and diamondoids are at the core of nanoscience. Comparable monodisperse silicon analogues are scarce. Herein, we report the synthesis of the parent siladodecahedrane, which represents the largest Platonic solid. It shares its pattern of pentagonal faces with the smallest fullerene, C

The strongly attractive noncovalent interactions of charged atoms or molecules with p-systems are important binding motifs in many chemical and biological systems. These so-called ion-pi interactions play a major role in enzymes, molecular recognition, and for the structure of proteins. In this work, a molecular test set termed IONPI19 is compiled for inter- and intramolecular ion-pi interactions, which is well balanced between anionic and cationic systems. The IONPI19 set includes interaction energies of significantly larger molecules (up to 133 atoms) than in other ion-pi test sets and covers a broad range of binding motifs. Accurate (local) coupled cluster values are provided as reference. Overall, 18 density functional approximations, including seven (meta-)GGAs, seven hybrid functionals, and four double hybrid functionals combined with three different London dispersion corrections, are benchmarked for interaction energies. DFT results are further compared to wave function based methods such as MP2 and dispersion corrected Hartree-Fock. Also the performanceof semiempirical QM methods such as the GFNn-xTB and PMx family of methods is tested. It is shown that dispersion-uncorrected DFT underestimates ion-pi interactions significantly, even though electrostatic interactions dominate the overall binding. Accordingly, the new charge dependent D4 dispersion model is found to be consistently better than the standard D3 correction. Furthermore, the functional performance trend along Jacob’s ladder is generally obeyed and the reduction of the self-interaction error leads to an improvement of (double) hybrid functionals over (meta-)GGAs, even though the effect of the SIE is smaller than expected. Overall, the double hybrids PWPB95-D4/QZ and revDSD-PBEP86-D4/QZ turned out to be the most reliable among all assessed methods in predicting ion-pi interactions, which opens up new perspectives for systems where coupled cluster calculations are no longer computationally feasible.

International audience; BACKGROUND: Patients who have had a stroke with unknown time of onset have been previously excluded from thrombolysis. We aimed to establish whether intravenous alteplase is safe and effective in such patients when salvageable tissue has been identified with imaging biomarkers. METHODS: We did a systematic review and meta-analysis of individual patient data for trials published before Sept 21, 2020. Randomised trials of intravenous alteplase versus standard of care or placebo in adults with stroke with unknown time of onset with perfusion-diffusion MRI, perfusion CT, or MRI with diffusion weighted imaging-fluid attenuated inversion recovery (DWI-FLAIR) mismatch were eligible. The primary outcome was favourable functional outcome (score of 0-1 on the modified Rankin Scale [mRS]) at 90 days indicating no disability using an unconditional mixed-effect logistic-regression model fitted to estimate the treatment effect. Secondary outcomes were mRS shift towards a better functional outcome and independent outcome (mRS 0-2) at 90 days. Safety outcomes included death, severe disability or death (mRS score 4-6), and symptomatic intracranial haemorrhage. This study is registered with PROSPERO, CRD42020166903. FINDINGS: Of 249 identified abstracts, four trials met our eligibility criteria for inclusion: WAKE-UP, EXTEND, THAWS, and ECASS-4. The four trials provided individual patient data for 843 individuals, of whom 429 (51%) were assigned to alteplase and 414 (49%) to placebo or standard care. A favourable outcome occurred in 199 (47%) of 420 patients with alteplase and in 160 (39%) of 409 patients among controls (adjusted odds ratio [OR] 1·49 [95% CI 1·10-2·03]; p=0·011), with low heterogeneity across studies (I(2)=27%). Alteplase was associated with a significant shift towards better functional outcome (adjusted common OR 1·38 [95% CI 1·05-1·80]; p=0·019), and a higher odds of independent outcome (adjusted OR 1·50 [1·06-2·12]; p=0·022). In the alteplase group, 90 (21%) patients were severely disabled or died (mRS score 4-6), compared with 102 (25%) patients in the control group (adjusted OR 0·76 [0·52-1·11]; p=0·15). 27 (6%) patients died in the alteplase group and 14 (3%) patients died among controls (adjusted OR 2·06 [1·03-4·09]; p=0·040). The prevalence of symptomatic intracranial haemorrhage was higher in the alteplase group than among controls (11 [3%] vs two [\textless1%], adjusted OR 5·58 [1·22-25·50]; p=0·024). INTERPRETATION: In patients who have had a stroke with unknown time of onset with a DWI-FLAIR or perfusion mismatch, intravenous alteplase resulted in better functional outcome at 90 days than placebo or standard care. A net benefit was observed for all functional outcomes despite an increased risk of symptomatic intracranial haemorrhage. Although there were more deaths with alteplase than placebo, there were fewer cases of severe disability or death. FUNDING: None.

The application of quantum chemical, automatic multilevel modeling workflows for the determination of thermodynamic (e.g., conformation equilibria, partition coefficients, pKa values) and spectroscopic properties of relatively large, nonrigid molecules in solution is described. Key points are the computation of rather complete structure (conformer) ensembles with extremely fast but still reasonable GFN2-xTB or GFN-FF semiempirical methods in the CREST searching approach and subsequent refinement at a recently developed, accurate r2SCAN-3c DFT composite level. Solvation effects are included in all steps by accurate continuum solvation models (ALPB, (D)COSMO-RS). Consistent inclusion of thermostatistical contributions in the framework of the modified rigid-rotor-harmonic-oscillator approximation (mRRHO) based on xTB/FF computed PES is also recommended.

The recently proposed r