Many studies have examined brain states in an effort to predict individual differences in capacity for learning, with overall moderate results. The present study investigated how measures of cortical network function acquired at rest using dense-array EEG (256 leads) predict subsequent acquisition of a new motor skill. Brain activity was recorded in 17 healthy young subjects during three minutes of wakeful rest prior to a single motor skill training session on a digital version of the pursuit rotor task. Practice was associated with significant gains in task performance (% time on target increased from 24% to 41%, p < 0.0001). Using a partial least squares regression (PLS) model, coherence with the region of the left primary motor area (M1) in resting EEG data was a strong predictor of motor skill acquisition (R2 = 0.81 in a leave-one-out cross-validation analysis), exceeding the information provided by baseline behavior and demographics. Within this PLS model, greater skill acquisition was predicted by higher connectivity between M1 and left parietal cortex, possibly reflecting greater capacity for visuomotor integration, and by lower connectivity between M1 and left frontal-premotor areas, possibly reflecting differences in motor planning strategies. EEG coherence, which reflects functional connectivity, predicts individual motor skill acquisition with a level of accuracy that is remarkably high compared to prior reports using EEG or fMRI measures.

The performance of the high-end optoelectronic devices is essentially influenced by the intrinsic relaxation mechanisms pursued by the hot carriers. Therefore, the key toward achieving progression in such fields lies in developing a complete understanding of the involved carrier cooling dynamics. In this work, an endeavor has been made to highlight the difference in the cooling mechanisms in 2D CsPbBr 3 nanosheets (NSs) and their 3D counterpart nanocrystals (NCs) with the aid of femtosecond broad-band pump− probe spectroscopy, varying the excitation energies. The exciton and biexciton dynamics in both systems are found to be retarded upon increasing the excitation energy. However, in contrast to 3D NCs, carrier cooling is found to be faster in the 2D system, regardless of the excitation energy used, attributing this to less efficient charge screening by Froḧlich interaction in low-dielectric medium. A similar trend is replicated in the biexciton formation rate since the formation is also found to be faster in NSs compared to NCs.

Albeit enormous achievement has already been made in photovoltaic and optoelectronic fields with perovskites, further advancement is needed to address key challenges encountered in these systems. Here, we synthesized polyhedral dodecahedron cesium lead bromide (dodecahedron-CsPbBr3) perovskite, which offers new polar facets exposed on the surface, longer carrier lifetime, and high photoluminescence (PL) quantum yield. PL investigation conducted at cryogenic temperature for dodecahedron-CsPbBr3 is clearly indicative of the absence of bound excitons originating from shallow traps, which otherwise are prevalent in conventional CsPbBr3 nanocubes (cube). The prolonged carrier cooling and 20–30% enhanced biexciton yield from transient absorption (TA) studies can be directly correlated with rapid polaron formation (0.25 ps) and defect-free nature of dodecahedron-CsPbBr3. Furthermore, temperature-dependent TA studies illustrate accelerated carrier cooling as the lattice temperature is lowered up to 5 K, which is related to the incapability of the lattice to support polarons. Terahertz (THz) spectroscopic measurements reflect lower carrier mobility in dodecahedron-CsPbBr3 than that in cube-CsPbBr3, validating the claim of slower carrier cooling as demonstrated by TA studies. These findings make dodecahedron-CsPbBr3 a potential contender for advanced next-generation efficient optoelectronic devices.

Background: Early diagnosis of stroke optimizes reperfusion therapies, but behavioral measures have incomplete accuracy. EEG has high sensitivity for immediately detecting brain ischemia. This pilot study aimed to evaluate feasibility and utility of EEG for identifying patients with a large acute ischemic stroke during Emergency Department evaluation, as these data might be useful in the pre-hospital setting. Methods: A 3-minute resting EEG was recorded using a dense-array (256-lead) system in patients with suspected acute stroke arriving at the Emergency Department of a US Comprehensive Stroke Center. Results: An EEG was recorded in 24 subjects, 14 with acute cerebral ischemia (including 5 with large acute ischemic stroke) and 10 without acute cerebral ischemia. Median time from stroke onset to EEG was 6.6 hours; and from Emergency Department arrival to EEG, 1.9 hours. Delta band power (p=0.004) and the alpha/delta frequency band ratio (p=0.0006) each significantly distinguished patients with large acute ischemic stroke (n=5) from all other patients with suspected stroke (n=19), with the best diagnostic utility coming from contralesional hemisphere signals. Larger infarct volume correlated with higher EEG power in the alpha/delta frequency band ratio within both the ipsilesional (r=−0.64, p=0.013) and the contralesional (r=−0.78, p=0.001) hemispheres. Conclusions: Within hours of stroke onset, EEG measures (1) identify patients with large acute ischemic stroke and (2) correlate with infarct volume. These results suggest that EEG measures of brain function may be useful to improve diagnosis of large acute ischemic stroke in the Emergency Department, findings that might be useful to pre-hospital applications.

Comprehensive understanding of charge carrier dynamics in the heterostructure based photocatalytic materials will strengthen their candidature as future solar energy harvesting resources. Here, in this work, the g-C3N4(CN)/ZnIn2S4 (ZIS) heterostructure was successfully synthesized and a direct spectroscopic correlation was established between excited-state charge carrier dynamics and enhanced photocatalytic activity using ultrafast transient absorption (TA) spectroscopy. TA analysis demonstrated the dominance of hot electron transfer over the band edge one. The photogenerated hot electrons migrated from the high-energy excitonic states of CN toward ZIS in the subpicosecond time scale. Broad-band (UV to NIR) ultrafast transient pump–probe spectroscopy revealed the collective effect of hot electron transfer as well as trap-state mediated electron delocalization in the enhanced photocatalytic H2 evolution. This work reveals the role of photogenerated carriers in the photocatalytic performance of the CN/ZIS heterostructure and would create a new avenue toward the advancement of CN based heterostructure in photocatalytic devices.