Nano Ag-Deposited BaTiO₃ Hybrid Particles as Fillers for Polymeric Dielectric Composites: Toward High Dielectric Constant and Suppressed Loss

Nano Ag-deposited BaTiO₃ (BT-Ag) hybrid particles usable as fillers for flexible polymeric composites to obtain high dielectric constant, low conductivity, and low dielectric loss were developed. BT-Ag hybrid particles were synthesized via a seed-mediated growing process by a redox reaction between silver nitrate and ethylene glycol. Nano Ag particles with a size less than 20 nm were discretely grown on the surface of the 100 nm BaTiO₃. The similar lattice spacing of the (1 1 1) planes of BT and Ag led to the hetero-epitaxial growth of Ag on the BT surface. The thickness of the coherent interface was about 3 nm. The adhesion of Ag to BT efficiently prevented the continuous contact between Ag particles in the polyvinylidene fluoride (PVDF) matrix and suppressed the formation of the conducting path in the composite. As a result, with a filler loading of 43.4 vol %, the composite exhibited a dielectric constant (<i>D</i>_k) value of 94.3 and dielectric loss (tan δ) of 0.06 at 1 kHz. An even higher <i>D</i>_k value of 160 at 1 kHz (16 times larger than that of PVDF) was obtained when the content of BT-Ag was further increased, with low conductivity (σ < 10^–5 S m^–1) and low dielectric loss (tan δ = 0.11), demonstrating promising applications in the electronic devices

Performance of the hybrid systems in the random and ‘4Q’ cultures.

<p><b>A.</b> Trajectory of the robot in a successful search task. The blue dot represents the location of the object, the red arrows represent the direction of the head of the robot, and the deep red dots represent the robot’s location, in which every time the neural network makes the decision. <b>B.</b> The detailed data analysis of the search task in A. from top to bottom, the first figure shows the distance between the object and the robot; the second figure shows the relative location between the object and the robot; the third figure shows the correct times of command executed by the robot and the X label represents the number of total commands from the beginning until now; the fourth figure shows the direction determined by the neural network. At the 0s time point, the robot has no action because the power is off. <b>C.</b> Box-plot of the correct turning percentage of the robot before reaching the object in both kinds of cultures, the percentage of the ‘4Q’ cultures is statistically higher. <b>D.</b> Box-plot of the time spent on reaching the object in both kinds of cultures, the time of spending in the ‘4Q’ cultures is statistically less, with 10 reaching in 3 random cultures and 12 reaching in 4 ‘4Q’ cultures. The datasets used in figure D are the same with C. Box range: percentile 25–75; box whiskers: percentile 5–95; line: median. Two-sample Kolmogorov-Smirnov Z test for nonparametric test, significant differences are indicated by asterisks, and the significance level = *P < 0.05.</p

Framework of the neuro-robot system.

<p>Two parts are included in this hybrid system:(i) Main PC components, employed to run the developed software tools, comprising the stimulator, the MEA coupled to live neurons, the amplification, and the data acquisition card; (ii) Slave PC, hosting the robot control software to command the robot system. The main PC communicates with the slave PC by a mean of network port running the TCP/IP protocol.</p

Evolution of performance of the neuro-robot system.

<p><b>A.</b> Trajectories of the robot in three successful search tasks. The blue dot represents the location of the object, the yellow, red, and blue arrows represent the direction of the head of robot, and the yellow, light red, and deep red dots represent the robot’s location every time the neural network outputs the decision during three different time phases, respectively. <b>B.</b> Histogram of the time spent by the robot in reaching the object in both the cultures during the three time phases. Statistics of the time spent reaching the object during the three time phases are calculated (mean ± S.D). <b>C.</b> Histogram of the correct turning percentage of the robot in both types of culture. The statistics for the correct turning of the two directions during three time phases are calculated, respectively. Blue bar is left turning (mean ± S.D), and red bar is right turning (mean ± S.D). Two-sample Kolmogorov- Smirnov Z test, significant differences between two datasets are indicated by asterisks, and the significance level = *P < 0.05.</p

Home-made stimulator and the robot control software.

<p><b>A.</b> Implementation of the stimulator system including the pre-amplifier of the existing recording system. <b>B</b>. A graph user interface (GUI) employed to control the robot is written by MFC. The monitor in the left side of the GUI is able to display the position of the robot in real time; the buttons in the middle of the panel are employed to manually control the robot; and the right side of the panel can connect with the main PC and display the information from/to the main PC.</p

Flow chart showing the selection of the study sample from the continuous National Health and Nutrition Examination Survey (NHANES).

All analyses presented in this paper were based on 1182 surveyed participants, each with complete anthropometric, blood-based indicator, and covariable data.</p

Application of Hierarchical Dissociated Neural Network in Closed-Loop Hybrid System Integrating Biological and Mechanical Intelligence

<div><p>Neural networks are considered the origin of intelligence in organisms. In this paper, a new design of an intelligent system merging biological intelligence with artificial intelligence was created. It was based on a neural controller bidirectionally connected to an actual mobile robot to implement a novel vehicle. Two types of experimental preparations were utilized as the neural controller including ‘random’ and ‘4Q’ (cultured neurons artificially divided into four interconnected parts) neural network. Compared to the random cultures, the ‘4Q’ cultures presented absolutely different activities, and the robot controlled by the ‘4Q’ network presented better capabilities in search tasks. Our results showed that neural cultures could be successfully employed to control an artificial agent; the robot performed better and better with the stimulus because of the short-term plasticity. A new framework is provided to investigate the bidirectional biological-artificial interface and develop new strategies for a future intelligent system using these simplified model systems.</p></div

Manufacture of the ‘4Q’ cultures with the tailor-made PDMS.

<p><b>A.</b> Schematic of PDMS device fabrication. <b>B</b> Schematic of the PDMS device attached to 4Q MEA <b>C.</b> Physical map of the PDMS device attached to 4Q MEA.</p

Four-well neural network on the ‘4Q’ MEA.

<p><b>A.</b> Dissociated neurons coupled to MEA are cultured to ‘4Q’ shape with a PDMS. The white raised dots (marked by the arrow) are the cell bodies, and black dots are the electrodes. <b>B.</b> One of the four quadrants is zoomed in to illustrate more details of the culture. The light raised dots are the cell bodies. <b>C.</b> Raw electrode data of the ‘4Q’ culture are displayed. The 2 seconds of spontaneous activity in a total of 59 electrodes (electrode in row 5 column 1 is ground electrode) were acquired from a dissociated culture of 15 DIV. The augmented amplitudes recorded in these electrodes suggest occurrence of the firing spike. The dataset presented here is similar to Fig <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0127452#pone.0127452.g006" target="_blank">6C</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0127452#pone.0127452.g006" target="_blank">6D</a>.</p

Activities evoked by a different stimulus in the random and ‘4Q’ cultures.

<p><b>A. B.</b> Raw electrode data of the random culture are displayed. The 2 seconds of activities evoked by the electrodes in the column 1 row 6 (A) and column 7 row 4 (B) in a total of 59 electrodes(electrode in row 5 column 1 is ground electrode) were acquired from a dissociated culture of 16 DIV. <b>C.D.</b> Raw electrode data of the ‘4Q’ culture are displayed. 2 seconds of activities evoked by the electrodes in the column 8 row 2 (C) and column 1 row 7 (D) in a total of 59 electrodes were acquired from a dissociated culture of 15 DIV. The augmented amplitudes recorded in these electrodes suggested occurrence of the firing spike.</p