P300 (PZ) trends in the training and control groups.

<p>A is P300 changes between the pre- and post-test in the training group, and B is the results of the control group. Scalp topographies of the two groups on P300 are demonstrated on C.</p

Correlations of Increment in accuracy, reaction time and additive value in N160, P200, P300.

<p>Correlations of Increment in accuracy, reaction time and additive value in N160, P200, P300.</p

P200 (FZ) trends in the training and control groups.

<p>A is P200 changes between the pre- and post-test in the training group, and B is the results of the control group. Scalp topographies of the two groups on P200 are demonstrated on C.</p

N160 trends of training and control groups (P7, P8).

<p>A and C are the training group results of pre- and post-test, and B and D are the control group results. Scalp topographies of the two groups on N160 are demonstrated on E.</p

Understanding Fast and Robust Thermo-osmotic Flows through Carbon Nanotube Membranes: Thermodynamics Meets Hydrodynamics

Following our recent theoretical prediction of the giant thermo-osmotic response of the water–graphene interface, we explore the practical implementation of waste heat harvesting with carbon-based membranes, focusing on model membranes of carbon nanotubes (CNT). To that aim, we combine molecular dynamics simulations and an analytical model considering the details of hydrodynamics in the membrane and at the tube entrances. The analytical model and the simulation results match quantitatively, highlighting the need to take into account both thermodynamics and hydrodynamics to predict thermo-osmotic flows through membranes. We show that, despite viscous entrance effects and a thermal short-circuit mechanism, CNT membranes can generate very fast thermo-osmotic flows, which can overcome the osmotic pressure of seawater. We then show that in small tubes confinement has a complex effect on the flow and can even reverse the flow direction. Beyond CNT membranes, our analytical model can guide the search for other membranes to generate fast and robust thermo-osmotic flows

Accuracy (ACC; %) and Reaction Time (RT; ms) of pre and post training 2-back working memory task.

<p>Excluded data outside three standard deviations (STD) and wrong responses.</p

Demonstration of Location Working Memory Task.

<p>Demonstration of Location Working Memory Task.</p

Validation of Spectra and Phase in Sub‑1 cm^–1 Resolution Sum-Frequency Generation Vibrational Spectroscopy through Internal Heterodyne Phase-Resolved Measurement

Reliable determination of the spectral features and their phases in sum-frequency generation vibrational spectroscopy (SFG-VS) for surfaces with closely overlapping peaks has been a standing issue. Here we present two approaches toward resolving such issue. The first utilizes the high-resolution and accurate line shape from the recently developed subwavenumber high-resolution broadband SFG-VS (HR-BB-SFG-VS), from which the detail spectral parameters, including relative spectral phases, of overlapping peaks can be determined through reliable spectral fitting. These results are further validated by using the second method that utilizes the azimuthal angle phase dependence of the z-cut α-quartz crystal, a common phase standard, through the spectral interference between the SFG fields of the quartz surface, as the internal phase reference, and the adsorbed molecular layer. Even though this approach is limited to molecular layers that can be transferred or deposited onto the quartz surface, it is simple and straightforward, as it requires only an internal phase standard with a single measurement that is free of phase drifts. More importantly, it provides unambiguous SFG spectral phase information on such surfaces. Using this method, the absolute phase of the molecular susceptibility tensors of the CH₃, CH₂, and chiral C–H groups in different Langmuir–Blodgett (LB) molecular monolayers and drop-cast peptide films are determined. These two approaches are fully consistent with and complement to each other, making both easily applicable tools in SFG-VS studies. More importantly, because the HR-BB-SFG-VS technique can be easily applied to various surfaces and interfaces, such validation of the spectral and phase information from HR-BB-SFG-VS measurement demonstrates it as one of the most promising tools for interrogating the detailed structure and interactions of complex molecular interfaces

Chiral Sum Frequency Generation Spectroscopy for Characterizing Protein Secondary Structures at Interfaces

<i>In situ</i> and real-time characterization of protein secondary structures at interfaces is important in biological and bioengineering sciences, yet remains technically challenging. In this study, we used chiral sum frequency generation (SFG) spectroscopy to establish a set of vibrational optical markers for characterizing protein secondary structures at interfaces. We discovered that the N–H stretches along the peptide backbones of α-helices can be detected in chiral SFG spectra. We further observed that the chiral vibrational signatures of the N–H stretch together with the peptide amide I are unique to α-helix, β-sheet, and random coil at interfaces. Using these chiral vibrational signatures, we studied the aggregation of human islet amyloid polypeptide (hIAPP), which is implicated in type II diabetes. We observed <i>in situ</i> and in real time the misfolding of hIAPP from random coils to α-helices and then β-sheets upon interaction with a lipid–water interface. Our findings show that chiral SFG spectroscopy is a powerful tool to follow changes in protein conformations at interfaces and identify interfacial protein secondary structures that elude conventional techniques

C–H Stretch for Probing Kinetics of Self-Assembly into Macromolecular Chiral Structures at Interfaces by Chiral Sum Frequency Generation Spectroscopy

Self-assembly of molecules into chiral macromolecular and supramolecular structures at interfaces is important in various fields, such as biomedicine, polymer sciences, material sciences, and supramolecular chemistry. However, probing the kinetics at interfaces remains challenging because it requires a real-time method that has selectivity to both interface and chirality. Here, we introduce an <i>in situ</i> approach of using the C–H stretch as a vibrational probe detected by chiral sum frequency generation spectroscopy (cSFG). We showed that the C–H stretch cSFG signals of an amphiphilic peptide (LK₇β) can reveal the kinetics of its self-assembly into chiral β-sheet structures at the air–water interface. The cSFG experiments in conjunction with measurements of surface pressure allow us to propose a mechanism of the self-assembly process, which involves an immediate adsorption of disordered structures followed by a lag phase before the self-assembly into chiral antiparallel β-sheet structures. Our method of using the C–H stretch signals implies a general application of cSFG to study the self-assembly of bioactive, simple organic, and polymeric molecules into chiral macromolecular and supramolecular structures at interfaces, which will be useful in tackling problems, such as protein aggregation, rational design of functional materials, and fabrication of molecular devices