Organic-Inorganic Hybrid Synaptic Transistors: Methyl-Silsesquioxanes-Based Electric Double Layer for Enhanced Synaptic Functionality and CMOS Compatibility.

Electrical double-layer (EDL) synaptic transistors based on organic materials exhibit low thermal and chemical stability and are thus incompatible with complementary metal oxide semiconductor (CMOS) processes involving high-temperature operations. This paper proposes organic-inorganic hybrid synaptic transistors using methyl silsesquioxane (MSQ) as the electrolyte. MSQ, derived from the combination of inorganic silsesquioxanes and the organic methyl (-CH3) group, exhibits exceptional thermal and chemical stability, thus ensuring compatibility with CMOS processes. We fabricated Al/MSQ electrolyte/Pt capacitors, exhibiting a substantial capacitance of 1.89 µF/cm2 at 10 Hz. MSQ-based EDL synaptic transistors demonstrated various synaptic behaviors, such as excitatory post-synaptic current, paired-pulse facilitation, signal pass filtering, and spike-number-dependent plasticity. Additionally, we validated synaptic functions such as information storage and synapse weight adjustment, simulating brain synaptic operations through potentiation and depression. Notably, these synaptic operations demonstrated stability over five continuous operation cycles. Lastly, we trained a multi-layer artificial deep neural network (DNN) using a handwritten Modified National Institute of Standards and Technology image dataset. The DNN achieved an impressive recognition rate of 92.28%. The prepared MSQ-based EDL synaptic transistors, with excellent thermal/chemical stability, synaptic functionality, and compatibility with CMOS processes, harbor tremendous potential as materials for next-generation artificial synapse components.

Synthesis and Characterization of Diketopyrrolopyrrole-Based Aggregation-Induced Emission Nanoparticles for Bioimaging.

Conventional fluorescent dyes have the property of decreasing fluorescence due to aggregation-caused quenching effects at high concentrations, whereas aggregation-induced emission dyes have the property of increasing fluorescence as they aggregate with each other. In this study, diketopyrrolopyrrole-based long-wavelength aggregation-induced emission dyes were used to prepare biocompatible nanoparticles suitable for bioimaging. Aggregation-induced emission nanoparticles with the best morphology and photoluminescence intensity were obtained through a fast, simple preparation method using an ultrasonicator. The optimally prepared nanoparticles from 3,6-bis(4-((E)-4-(bis(40-(1,2,2-triphenylvinyl)-[1,10-biphenyl]-4-yl)amino)styryl)phenyl)-2,5-dihexyl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (DP-R2) with two functional groups having aggregation-induced emission properties and additional donating groups at the end of the triphenylamine groups were considered to have the greatest potential as a fluorescent probe for bioimaging. Furthermore, it was found that the tendency for aggregation-induced emission, which was apparent for the dye itself, became much more marked after the dyes were incorporated within nanoparticles. While the photoluminescence intensities of the dyes were observed to decrease rapidly over time, the prepared nanoparticles encapsulated within the biocompatible polymers maintained their initial optical properties very well. Lastly, when the cell viability test was conducted, excellent biocompatibility was demonstrated for each of the prepared nanoparticles.

Multi-bandgap Solar Energy Conversion via Combination of Microalgal Photosynthesis and Spectrally Selective Photovoltaic Cell.

Microalgal photosynthesis is a promising solar energy conversion process to produce high concentration biomass, which can be utilized in the various fields including bioenergy, food resources, and medicine. In this research, we study the optical design rule for microalgal cultivation systems, to efficiently utilize the solar energy and improve the photosynthesis efficiency. First, an organic luminescent dye of 3,6-Bis(4'-(diphenylamino)-1,1'-biphenyl-4-yl)-2,5-dihexyl-2,5-dihydropyrrolo3,4-c pyrrole -1,4-dione (D1) was coated on a photobioreactor (PBR) for microalgal cultivation. Unlike previous reports, there was no enhancement in the biomass productivities under artificial solar illuminations of 0.2 and 0.6 sun. We analyze the limitations and future design principles of the PBRs using photoluminescence under strong illumination. Second, as a multiple-bandgaps-scheme to maximize the conversion efficiency of solar energy, we propose a dual-energy generator that combines microalgal cultivation with spectrally selective photovoltaic cells (PVs). In the proposed system, the blue and green photons, of which high energy is not efficiently utilized in photosynthesis, are absorbed by a large-bandgap PV, generating electricity with a high open-circuit voltage (Voc) in reward for narrowing the absorption spectrum. Then, the unabsorbed red photons are guided into PBR and utilized for photosynthesis with high efficiency. Under an illumination of 7.2 kWh m-2 d-1, we experimentally verified that our dual-energy generator with C60-based PV can simultaneously produce 20.3 g m-2 d-1 of biomass and 220 Wh m-2 d-1 of electricity by utilizing multiple bandgaps in a single system.

Aggregation induced emission of diketopyrrolopyrrole (DPP) derivatives for highly fluorescent red films.

A large number of diketopyrrolopyrrole (DPP) compounds showing aggregation induced emission (AIE) have been reported in the past few years. However, although DPP compounds exhibited AIE and excellent luminescence properties, their luminescence properties in solid or film states were not much focused on. Here we synthesized and characterized a series of DPP compounds with triphenylamine (TPA) moieties to investigate the AIE properties in the solid film state depending on the functional groups (TPA, BTPA, and MTPA) attached to the TPA moieties. T2 and D2 thin films showed excellent fluorescence quantum yields of 31% and 26%, respectively, compared to an M2 thin film (9%). The restriction of an intramolecular rotation process could inhibit the aggregation induced quenching process and play a key role in achieving highly fluorescent molecules in the solid state.

Simple modification of basic dyes with bulky &symmetric WCAs for improving their solubilities in organic solvents without color change.

A simple and easy solubility enhancement of basic dyes was performed with bulky and symmetric weakly coordinating anions (WCAs). The WCAs decreased the ionic character of the dyes by broadening the partial charge distribution and causing a screening effect on the ionic bonding. This new modification with WCAs has advantages in that it has no influence on the optical properties of the dyes. The solubilities of unmodified and modified dyes were tested in several organic solvents. X-ray powder diffraction patterns of the dyes were measured. Color films were prepared with the dyes and their color loci were analyzed to evaluate the optical properties. By the modification with WCAs, commercial basic dyes showed sufficient solubilities for be applied to various applications while preserving their superior optical properties.

Modification of electrophysiological activity pattern after anterior thalamic deep brain stimulation for intractable epilepsy: report of 3 cases.

OBJECTIVE Thalamic stimulation can provoke electroencephalography (EEG) synchronization or desynchronization, which can help to reduce the occurrence of seizures in intractable epilepsy, though the underlying mechanism is not fully understood. Therefore, the authors investigated changes in EEG electrical activity to better understand the seizure-reducing effects of deep brain stimulation (DBS) in patients with intractable epilepsy. METHODS Electrical activation patterns in the epileptogenic brains of 3 patients were analyzed using classical low-resolution electromagnetic tomography analysis recursively applied (CLARA). Electrical activity recorded during thalamic stimulation was compared with that recorded during the preoperative and postoperative off-stimulation states in patients who underwent anterior thalamic nucleus DBS for intractable epilepsy. RESULTS Interictal EEG was fully synchronized to the ß frequency in the postoperative on-stimulation period. The CLARA showed that electrical activity during preoperative and postoperative off-stimulation states was localized in cortical and subcortical areas, including the insular, middle frontal, mesial temporal, and precentral areas. No electrical activity was localized in deep nucleus structures. However, with CLARA, electrical activity in the postoperative on-stimulation period was localized in the anterior cingulate area, basal ganglia, and midbrain. CONCLUSIONS Anterior thalamic stimulation could spread electrical current to the underlying neuronal networks that connect with the thalamus, which functions as a cortical pacemaker. Consequently, the thalamus could modify electrical activity within these neuronal networks and influence cortical EEG activity by inducing neuronal synchronization between the thalamus and cortical structures.

Initial response to antiepileptic drugs in patients with newly diagnosed epilepsy.

This study aimed to identify factors predicting the response to antiepileptic drugs in patients with newly diagnosed epilepsy. We prospectively studied 176 patients with newly diagnosed epilepsy. Patients were included if they had a history of two or more clinically definite unprovoked seizures, or had a definite epileptic focus on MRI or epileptiform discharges on electroencephalography if they had suffered only one seizure. The primary endpoint was seizure freedom during the initial 6 months of antiepileptic drug treatment. The secondary endpoint was the time to the first seizure during the maintenance period of antiepileptic drug treatment. A total of 100 patients were included, and seizure freedom for 6 months was achieved in 73 patients. The response to antiepileptic drugs was significantly lower in patients with early age at seizure onset (⩽ 16 versus >16 years old, odds ratio=4; 95% confidence interval [CI] 1.5-12.9; relative risk=1.4; 95% CI 1.1-1.8). In addition, the time to the first seizure during the maintenance period was significantly earlier in patients with age at seizure onset ⩽ 16 years compared with those with age at seizure onset >16 years on the Kaplan-Meier survival analysis (p=0.011). Early age at seizure onset is an important factor influencing the response to antiepileptic drugs in patients with newly diagnosed epilepsy.

Benign childhood epilepsy with centrotemporal spikes: to treat or not to treat.

BACKGROUND AND PURPOSE: The aim of this study was to evaluate the benefits and risks of oxcarbazepine (OXC) monotherapy in children with newly diagnosed, benign partial epilepsy based on clinico-electrical and neuropsychological evaluation over time. METHODS: The study was open label, prospective, multicenter based. A total of 39 children with BRE were involved in the study. They were randomized into two groups (T; treatment with OXC, NT; No treatment) to compare the effectiveness of OXC treatment. All children underwent EEGs with quantification and a comprehensive battery of neuropsychological tests at the first visit and follow up visit at 6 months. RESULTS: The subjects made a slight progress in general intelligence measures over time in both groups (95.4±10.5 to 97.6±7.5 for T, 107.6±17.3 to 111.4±18.6 for NT). Memory and frontal executive functions did not change over time in both groups in terms of the memory quotient (MQ) (106.7±27.5 to 103.4± 19.3 for T, 105.8±13.2 to 104.9±17.2 for NT) and executive intelligence quotient (EIQ) (114.7±18.3 to 108.9±12.5 for T, 100.6±25.1 to 101.2±13.9 for NT). However, when sub-domain scores were compared between the two groups, the treatment group got significantly worse over time in the verbal fluency test (11.5±3.8 to 8.0±1.4 for T, 10.3±3.9 to 11.5±2.1 for NT; p<0.05) and level 1 of Stroop test (9.3±3.0 to 7.5±1.3 for T, 11.0±3.7 to 11.2±2.6 for NT; p<0.05). The subjects might have cognitive and behavioral difficulties in association with frontal lobe dysfunctions, but these difficulties did not seem to be dependent on the number of seizures, the abundance of subclinical epileptiform discharges, or the anti-epileptic treatment. CONCLUSIONS: We think that OXC monotherapy is effective for children with BRE, but is to be given to the selected patients such as patients with prolonged or frequent seizures. However, further studies are needed to have a better understanding in this matter.

Acoustic streaming in lithotripsy fields: preliminary observation using a particle image velocimetry method.

This study considers the acoustic streaming in water produced by a lithotripsy pulse. Particle image velocimetry (PIV) method was employed to visualize the acoustic streaming produced by an electromagnetic shock wave generator using video images of the light scattering particles suspended in water. Visualized streaming features including several local peaks and vortexes around or at the beam focus were easily seen with naked eyes over all settings of the lithotripter from 10 to 18 kV. Magnitudes of the peak streaming velocity measured vary in the range of 10-40 mm s(-1) with charging voltage settings. Since the streaming velocity was estimated on the basis of a series of the video images of particles averaged over 1/60s, the time resolution limited by the video frame rate which is 1-2 orders of magnitude larger than driving acoustic activities, measured velocities are expected to be underestimated and were shown a similar order of magnitude lower than those calculated from a simple theoretical consideration. Despite such an underestimation, it was shown that, as predicted by theory, the magnitude of the streaming velocity measured by the present PIV method was proportional to acoustic intensity. In particular it has almost a linear correlation with peak negative pressures (r=0.98683, p=0.0018).