Bottom-up Synthesis and Characterization of Porous 12-Atom-Wide Armchair Graphene Nanoribbons.

Although several porous carbon/graphene nanoribbons (GNRs) have been prepared, a direct comparison of the electronic properties between a nonporous GNR and its periodically perforated counterpart is still missing. Here, we report the synthesis of porous 12-atom-wide armchair-edged GNRs from a bromoarene precursor on a Au(111) surface via hierarchical Ullmann and dehydrogenative coupling. The selective formation of porous 12-GNRs was achieved through thermodynamic and kinetic reaction control combined with tailored precursor design. The structure and electronic properties of the porous 12-GNR were elucidated by scanning tunneling microscopy/spectroscopy and density functional theory calculations, revealing that the pores induce a 2.17 eV band gap increase compared to the nonporous 12-AGNR on the same surface.

Synthesis of Tridecacene by Multistep Single-Molecule Manipulation.

Acenes represent a unique class of polycyclic aromatic hydrocarbons that have fascinated chemists and physicists due to their exceptional potential for use in organic electronics. While recent advances in on-surface synthesis have resulted in higher acenes up to dodecacene, a comprehensive understanding of their fundamental properties necessitates their expansion toward even longer homologues. Here, we demonstrate the on-surface synthesis of tridecacene via atom-manipulation-induced conformational preparation and dissociation of a trietheno-bridged precursor on a Au(111) surface. The generated tridecacene has been investigated by scanning tunneling microscopy and spectroscopy (STM/STS), combined with first-principles calculations. We observe that the STS transport gap (1.09 eV) shrinks again following the gap reopening of dodecacene (1.4 eV). Spin-polarized density functional theory calculations confirm an antiferromagnetic open-shell ground-state electronic configuration for tridecacene in the gas phase. Interestingly, tridecacene's open-shell character is significantly reduced upon interaction with the Au(111) surface despite being only physisorbed. The interaction with the surface leads to a lowering of the magnetization of tridecacene, a reduced gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), compared to the gas phase, and a reduced relative energy to the nonmagnetic state, making it nearly isoenergetic. These observations show qualitatively that the influence of the Au(111) substrate on the properties of long acenes is significant, which is important for interpreting the measured STS transport gaps. Our work contributes to a fundamental understanding of the electronic properties of long acenes, confirming a nonmonotonous length-dependent HOMO-LUMO gap, and to the development of multistep tip-assisted synthesis of elusive compounds.

Ion-Selective Assembly of Supertetrahedral Selenido Germanate Clusters for Alkali Metal Ion Capture and Separation.

Supertetrahedral chalcogenido (semi)metalate cluster-based frameworks possess high selectivity for alkali metal cations, matching the specific charge density of their inner surfaces, which enables their use as ion-exchange materials. Aggregates of the supertetrahedral chalcogenido metalate cluster offer even new perspectives for metal ion capture and separation. Herein, we report on ionothermal preparation of two corresponding model compounds, (C2C1Im)7[Cs@GeII4(GeIV4Se10)4] (1) and (C2C1Im)10[Na5(CN)6@Cu6(Ge4Se10)4(Cu)] (2). Their formation is reliant on one specific cation type each, Cs+ for 1 and Na+ for 2, thus providing promising separation potential during crystallization. Compound 1 is based on the largest discrete binary selenido germanate cluster reported to date and the first mixed-valent chalcogenido germanate(II/IV) supertetrahedron. Moreover, it adds to the few examples of chalcogenides capable of capturing Cs+ ions. Its high selectivity for Cs+ compared to that of Li+, Na+, K+, and Rb+ was confirmed by single-crystal X-ray diffraction, energy-dispersive X-ray spectroscopy, and electrospray ionization mass spectrometry. Quantum chemical studies indicate that smaller ions, K+ and Rb+, could also be embedded in an isolated cluster assembly, but as the cluster aggregate slightly distorts for crystallization, the selectivity for Cs+ becomes exclusive in the salt. The anionic substructure of compound 2 is based on a two-dimensional network of supramolecular assemblies and exhibits an exclusive preference for Na+. This work thus provides the first comprehensive insight into the selective incorporation of specific alkali metal ions into supramolecular aggregates of supertetrahedral chalcogenide clusters, as a promising basis for new ion trapping techniques─especially for heavy alkali metal ions that pose environmental challenges.

Sensory features of mental images in the framework of human actions.

What determines the sensory impression of a self-generated motor image? Motor imagery is a process in which subjects imagine executing a body movement with a strong kinesthetic and/or visual component from a first-person perspective. Both sensory modalities can be combined flexibly to form a motor image. 90 participants of varying ages had to freely generate motor images from a large set of movements. They were asked to rate their kinesthetic as well as their visual impression, the perceived vividness, and their personal experience with the imagined movement. Data were subjected to correlational analyses, linear regressions, and representation similarity analyses. Results showed that both action characteristics and experience drove the sensory impression of motor images with a strong individual component. We conclude that imagining actions that impose varying demands can be considered as reexperiencing actions by using one's own sensorimotor representations that represent not only individual experience but also action demands.

Neural simulation of actions: effector- versus action-specific motor maps within the human premotor and posterior parietal area?

This study addresses the controversy over how motor maps are organized during action simulation by examining whether action simulation states, that is, motor imagery and action observation, run on either effector-specific and/or action-specific motor maps. Subjects had to observe or imagine three types of movements effected by the right hand or the right foot with different action goals. The functional magnetic resonance imaging results showed an action-specific organization within premotor and posterior parietal areas of both hemispheres during action simulation, especially during action observation. There were also less pronounced effector-specific activation sites during both simulation processes. It is concluded that the premotor and parietal areas contain multiple motor maps rather than a single, continuous map of the body. The forms of simulation (observation, imagery), the task contexts (movements related to an object, with usual/unusual effector), and the underlying reason for performing the simulation (rate your subjective success afterwards) lead to the specific use of different representational motor maps within both regions. In our experimental setting, action-specific maps are dominant especially, during action observation, whereas effector-specific maps are recruited to only a lesser degree.

How equivalent are the action execution, imagery, and observation of intransitive movements? Revisiting the concept of somatotopy during action simulation.

Jeannerod (2001) hypothesized that action execution, imagery, and observation are functionally equivalent. This led to the major prediction that these motor states are based on the same action-specific and even effector-specific motor representations. The present study examined whether hand and foot movements are represented in a somatotopic manner during action execution, imagery, and action observation. The experiment contained ten conditions: three execution conditions, three imagery conditions, three observation conditions, and one baseline condition. In the nine experimental conditions, participants had to execute, observe, or imagine right-hand extension/flexion movements or right-foot extension/flexion movements. The fMRI results showed a somatotopic organization within the contralateral premotor and primary motor cortex during motor imagery and motor execution. However, there was no clear somatotopic organization of action observation in the given regions of interest within the contralateral hemisphere, although observation of these movements activated these areas significantly.

Early Serum Biomarkers for Intensive Care Unit Treatment within the First 24 Hours in Patients with Intracerebral Hemorrhage.

BACKGROUND: The prognostic significance of serum biomarkers in patients with intracerebral hemorrhage (ICH) is not well investigated concerning inhospital mortality (IHM) and cardiopulmonary events within the first 24 hours of intensive care unit (ICU) treatment. The influence of troponin I (TNI) value and cortisol value (CV) on cardiopulmonary events within the first 24 hours of ICU treatment was reported in subarachnoid hemorrhage patients, but not in ICH patients up to now. The aim of this study was to investigate the role of early serum biomarkers on IHM and TNI value and CV on cardiopulmonary events within the first 24 hours of ICU treatment. PATIENTS AND METHODS: A total of 329 patients with spontaneous ICH were retrospectively analyzed. Blood samples were taken on admission to measure serum biomarkers. The TNI value and CV were defined as biomarkers for cardiopulmonary stress. Demographic data, cardiopulmonary parameters, including norepinephrine application rate (NAR) in microgram per kilogram per minute and inspiratory oxygen fraction (FiO2) within the first 24 hours, and treatment regime were analyzed concerning their impact on ICU treatment and in hospital outcome. Binary logistic analysis was used to identify independent prognostic factors for IHM. RESULTS: Patients with initially nonelevated CVs required higher NAR (p = 0.01) and FiO2 (p = 0.046) within the first 24 hours of ICU treatment. Lower cholinesterase level (p = 0.004), higher NAR (p = 0.002), advanced age (p < 0.0001), larger ICH volume (p < 0.0001), presence of intraventricular hemorrhage (p = 0.007) and hydrocephalus (p = 0.009), raised level of C-reactive protein (p = 0.024), serum lactate (p = 0.003), and blood glucose (p = 0.05) on admission were significantly associated with IHM. In a multivariate model, age (odds ratio [OR]: 1.055; 95% confidence interval [CI]: 1.026-1.085; p < 0.0001), ICH volume (OR: 1.016; CI: 1.008-1.025; p < 0.0001), and Glasgow Coma Scale (GCS) score (OR: 0.680; CI: 0.605-0.764; p < 0.0001) on admission as well as requiring NAR (OR: 1.171; CI: 1.026-1.337; p = 0.02) and FiO2 (OR: 0.951; CI: 0.921-0.983, p = 0.003) within the first 24 hours were independent predictors of IHM. CONCLUSION: Higher levels of C-reactive protein, serum lactate, blood glucose, and lower cholinesterase level on admission were significantly associated with IHM. Patients with initially nonelevated CVs required higher NAR and FiO2 within the first 24 hours of ICU treatment. Furthermore, requiring an NAR > 0.5 µg/kg/min or an FiO2 > 0.21 were identified as additional independent predictors for IHM. These results could be helpful to improve ICU treatment in ICH patients.

Kekulene: On-Surface Synthesis, Orbital Structure, and Aromatic Stabilization.

We revisit the question of kekulene's aromaticity by focusing on the electronic structure of its frontier orbitals as determined by angle-resolved photoemission spectroscopy. To this end, we have developed a specially designed precursor, 1,4,7(2,7)-triphenanthrenacyclononaphane-2,5,8-triene, which allows us to prepare sufficient quantities of kekulene of high purity directly on a Cu(111) surface, as confirmed by scanning tunneling microscopy. Supported by density functional calculations, we determine the orbital structure of kekulene's highest occupied molecular orbital by photoemission tomography. In agreement with a recent aromaticity assessment of kekulene based solely on C-C bond lengths, we conclude that the π-conjugation of kekulene is better described by the Clar model rather than a superaromatic model. Thus, by exploiting the capabilities of photoemission tomography, we shed light on the question which consequences aromaticity holds for the frontier electronic structure of a π-conjugated molecule.

No transfer between conditions in balance training regimes relying on tasks with different postural demands: Specificity effects of two different serious games.

Despite the increasing use of video games involving whole body movements to enhance postural control in health prevention and rehabilitation, there is no consistent proof that training effects actually transfer to other balance tasks. The present study aimed to determine whether training effects on two different video-game-based training devices were task-specific or could be transferred to either postural control in quiet stance or to performance on the other device. 37 young healthy adults were split into three groups: two intervention groups that trained for 30min on either the Nintendo(®) Wii Fit Balance Board or the MFT Challenge Disc(®) three times per week for 4 weeks and a control group that received no training. All games require participants to control virtual avatars by shifting the center of mass in different directions. Both devices differ in their physical properties. The Balance Board provides a stable surface, whereas the Challenge Disc can be tilted in all directions. Dependent variables were the game scores on both devices and the center of pressure (COP) displacements measured via force plate. At posttest, both intervention groups showed significant increases in performance on the trained games compared to controls. However, there were no relevant transfer effects to performance on the untrained device and no changes in COP path length in quiet stance. These results suggest that training effects on both devices are highly specific and do not transfer to tasks with different postural demands.

The influence of expertise on brain activation of the action observation network during anticipation of tennis and volleyball serves.

In many daily activities, and especially in sport, it is necessary to predict the effects of others' actions in order to initiate appropriate responses. Recently, researchers have suggested that the action-observation network (AON) including the cerebellum plays an essential role during such anticipation, particularly in sport expert performers. In the present study, we examined the influence of task-specific expertise on the AON by investigating differences between two expert groups trained in different sports while anticipating action effects. Altogether, 15 tennis and 16 volleyball experts anticipated the direction of observed tennis and volleyball serves while undergoing functional magnetic resonance imaging (fMRI). The expert group in each sport acted as novice controls in the other sport with which they had only little experience. When contrasting anticipation in both expertise conditions with the corresponding untrained sport, a stronger activation of AON areas (SPL, SMA), and particularly of cerebellar structures, was observed. Furthermore, the neural activation within the cerebellum and the SPL was linearly correlated with participant's anticipation performance, irrespective of the specific expertise. For the SPL, this relationship also holds when an expert performs a domain-specific anticipation task. Notably, the stronger activation of the cerebellum as well as of the SMA and the SPL in the expertise conditions suggests that experts rely on their more fine-tuned perceptual-motor representations that have improved during years of training when anticipating the effects of others' actions in their preferred sport. The association of activation within the SPL and the cerebellum with the task achievement suggests that these areas are the predominant brain sites involved in fast motor predictions. The SPL reflects the processing of domain-specific contextual information and the cerebellum the usage of a predictive internal model to solve the anticipation task.