Exceptionally high OER & HER performances were achieved by rationally designing the electrode structure of non-noble NiFe materials.

Background Obsessive-compulsive disorder (OCD) is associated with regional hyperactivity in cortico-striatal circuits. However, the large-scale patterns of abnormal neural connectivity remain uncharacterized. Resting-state functional connectivity (rs-fcMRI) studies have shown altered connectivity within the implicated circuitry, but they have used seed-driven approaches wherein a circuit of interest is defined a priori. This limits their ability to identify network abnormalities beyond the prevailing framework. This limitation is particularly problematic within the prefrontal cortex (PFC), which is large and heterogeneous and where a priori specification of seeds is therefore difficult. A hypothesis-neutral data-driven approach to the analysis of connectivity is vital. Method We analyzed rs-fcMRI data collected at 3T in 27 OCD patients and 66 matched controls using a recently developed data-driven global brain connectivity (GBC) method, both within the PFC and across the whole brain. Results We found clusters of decreased connectivity in the left lateral PFC in both whole-brain and PFC-restricted analyses. Increased GBC was found in the right putamen and left cerebellar cortex. Within ROIs in the basal ganglia and thalamus, we identified increased GBC in dorsal striatum and anterior thalamus, which was reduced in patients on medication. The ventral striatum/nucleus accumbens exhibited decreased global connectivity, but increased connectivity specifically with the ventral anterior cingulate cortex in subjects with OCD. Conclusion These findings identify previously uncharacterized PFC and basal ganglia dysconnectivity in OCD and reveal differentially altered GBC in dorsal and ventral striatum. Results highlight complex disturbances in PFC networks, which could contribute to disrupted cortical-striatal-cerebellar circuits in OCD.

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The slow kinetics of oxygen evolution reaction (OER) causes high power consumption for electrochemical water splitting. Various strategies have been attempted to accelerate the OER rate, but there are few studies on regulating the transport of reactants especially under large current densities when the mass transfer factor dominates the evolution reactions. Herein, NixFe1–x alloy nanocones arrays (with ≈2 nm surface NiO/NiFe(OH)2 layer) are adopted to boost the transport of reactants. Finite element analysis suggests that the high‐curvature tips can enhance the local electric field, which induces an order of magnitude higher concentration of hydroxide ions (OH−) at the active sites and promotes intrinsic OER activity by 67% at 1.5 V. Experimental results show that a fabricated NiFe nanocone array electrode, with optimized alloy composition, has a small overpotential of 190 mV at 10 mA cm−2 and 255 mV at 500 mA cm−2. When calibrated by electrochemical surface area, the nanocones electrode outperforms the state‐of‐the‐art OER electrocatalysts. The positive effect of the tip‐enhanced local electric field in promoting mass transfer is also confirmed by comparing samples with different tip curvature radii. It is suggested that this local field enhanced OER kinetics is a generic effect to other OER catalysts.

A hallmark of cognitive control is the ability to rein in impulsive responses. Previously, we used a Bayesian model to describe trial-by-trial likelihood of the stop signal or p(Stop) and related regional activations to p(Stop) to response slowing in a stop signal task. Here, we characterized the regional processes of conflict anticipation in association with intersubject variation in impulse control in 114 young adults. We computed the stop signal reaction time (SSRT) and a measure of motor urgency, indexed by the reaction time (RT) difference between go and stop error trials or "GoRT Ϫ SERT," where GoRT is the go trial RT and SERT is the stop error RT. Motor urgency and SSRT were positively correlated across subjects. A linear regression identified regional activations to p(Stop), each in correlation with SSRT and motor urgency. We hypothesized that shared neural activities mediate the correlation between motor urgency and SSRT in proactive control of impulsivity. Activation of the ventromedial prefrontal cortex, posterior cingulate cortex and right superior frontal gyrus (SFG) during conflict anticipation correlated negatively with the SSRT. Activation of the right SFG also correlated negatively with GoRT Ϫ SERT. Therefore, activation of the right SFG was associated with more efficient response inhibition and less motor urgency. A mediation analysis showed that right SFG activation to conflict anticipation mediates the correlation between SSRT and motor urgency bidirectionally. The current results highlight a specific role of the right SFG in translating conflict anticipation to the control of impulsive response, which is consistent with earlier studies suggesting its function in action restraint.

Deficits in cognitive control are implicated in cocaine dependence. Previously, combining functional magnetic resonance imaging and a stop signal task, we demonstrated altered cognitive control in cocaine-dependent individuals. However, the clinical implications of these cross-sectional findings and, in particular, whether the changes were associated with relapse to drug use, were not clear. In a prospective study, we recruited 97 treatment-seeking individuals with cocaine dependence to perform the stop signal task during functional magnetic resonance imaging and participate in follow-up assessments for 3 months, during which time cocaine use was evaluated with timeline follow back and ascertained by urine toxicology tests. Functional magnetic resonance imaging data were analysed using general linear models as implemented in Statistical Parametric Mapping 8, with the contrast 'stop error greater than stop success trials' to index error processing. Using voxelwise analysis with logistic and Cox regressions, we identified brain activations of error processing that predict relapse and time to relapse. In females, decreased error-related activations of the thalamus and dorsal anterior cingulate cortex predicted relapse and an earlier time to relapse. In males, decreased error-related activations of the dorsal anterior cingulate cortex and left insula predicted relapse and an earlier time to relapse. These regional activations were validated with data resampling and predicted relapse with an average area under the curve of 0.849 in receiver operating characteristic analyses. These findings provide direct evidence linking deficits in cognitive control to clinical outcome in a moderate-sized cohort of cocaine-dependent individuals. These results may provide a useful basis for future studies to examine how psychosocial factors interact with cognitive control to determine drug use and to evaluate the efficacy of pharmacological or behavioural treatment in remediating deficits of cognitive control in cocaine addicts.

The locus coeruleus (LC) provides the primary noradrenergic inputs to the cerebral cortex. Despite numerous animal studies documenting the functions of the LC, research in humans is hampered by the small volume of this midbrain nucleus. Here, we took advantage of a probabilistic template, explored the cerebral functional connectivity of the LC with resting-state fMRI data of 250 healthy adults, and verified the findings by accounting for physiological noise in another data set. In addition, we contrasted connectivities of the LC and the ventral tegmental area/substantia nigra pars compacta. The results highlighted both shared and distinct connectivity of these 2 midbrain structures, as well as an opposite pattern of connectivity to bilateral amygdala, pulvinar, and right anterior insula. Additionally, LC connectivity to the fronto-parietal cortex and the cerebellum increases with age and connectivity to the visual cortex decreases with age. These findings may facilitate studies of the role of the LC in arousal, saliency responses and cognitive motor control and in the behavioral and cognitive manifestations during healthy and disordered aging. Although the first to demonstrate whole-brain LC connectivity, these findings need to be confirmed with high-resolution imaging.

We report the observations of unexpected layer-dependent, strong, and anisotropic second harmonic generations (SHGs) in atomically thin ReS 2 . Appreciable (negligible ) SHGs are obtained from even (odd) numbers of ReS 2 layers, which is opposite to the layer-dependence of SHGs in group VI transition metal dichalcogenides, such as MoS 2 and WS 2 . The results are analyzed from ReS 2 's crystal structure, implying second harmonic polarizations generated from the interlayer coupling. Pumped by a telecomband laser, SHG from the bilayer ReS 2 is almost one order of magnitude larger than that from the monolayer WS 2 . The estimated second-order nonlinear susceptibility of 900 pm/V is remarkably high among those reported in two-dimensional materials. The laser polarization dependence of ReS 2 's SHG is strongly anisotropic and indicates its distorted lattice structure with more unequal and non-zero second-order susceptibility elements.keywords: second harmonic generation, transition metal dichalcogenides, rhenium disulfide, polarization, interlayer coupling, exciton resonance 1 arXiv:1808.03928v1 [physics.optics]