Photonic crystal-assisted sub-bandgap photocatalysis via triplet-triplet annihilation upconversion for the degradation of environmental organic pollutants.

This study explores novel approaches to enhance photocatalysis efficiency by introducing a photonic crystal (PC)-enhanced, multi-layered sub-bandgap photocatalytic reactor. The design aims to effectively utilize sub-bandgap photons that might otherwise go unused. The device consists of three types of layers: (1) two polymeric triplet-triplet annihilation upconversion (TTA-UC) layers converting low-energy green photons (λEx = 532 nm, 2.33 eV) to high-energy blue photons (λEm = 425 nm, 2.92 eV), (2) a platinum-decorated WO3 layer (Eg = 2.8 eV) serving as a visible-light photocatalyst, and (3) a PC layer optimizing both TTA-UC and photocatalysis. The integration of the PC layer resulted in a 1.9-fold increase in UC emission and a 7.9-fold enhancement in hydroxyl radical (•OH) generation, achieved under low-intensity sub-bandgap irradiation (17.6 mW cm-2). Consequently, the combined layered structure of TTA/Pt-WO3/TTA/PC achieved a remarkable 38.8-fold improvement in •OH production, leading to outstanding degradation capability for various organic pollutants (e.g., 4-chlorophenol, bisphenol A, and methylene blue). This multi-layered sub-bandgap photocatalytic structure, which uniquely combines TTA-UC and PC layers, offers valuable insights into designing efficient photocatalytic systems for future solar-driven environmental remediation.

Association of Body Image Distortion with Smartphone Dependency and Usage Time in Adolescents: A Cross-Sectional Korean Youth Study.

Background: Adolescent dependency on smartphones is the highest among all age groups. Adolescents can be influenced to evaluate their body image by popular ideals about beautiful bodies via smartphone content, which can cause body image distortion. This study aimed to examine the association between body image distortion and smartphone dependency and the duration of smartphone usage among Korean adolescents. Methods: This study used data from the 16th Korean Youth Risk Behavior Web-Based Survey (2020), and included 42,981 participants, who were grouped according to self-reported duration of smartphone usage and smartphone dependency, as measured by a questionnaire. Body image distortion is defined as an exaggerated subjective body image compared to the actual body image. Multivariable-adjusted logistic regression was used to determine the odds ratios (ORs) with 95% confidence intervals (CIs) of body image distortion on smartphone dependency and usage time after adjusting for various factors related to body image distortion. Results: Among the 42,981 participants, both moderate and high levels of smartphone dependency were associated with body image distortion in boys (moderate: adjusted OR [aOR], 1.11; 95% CI, 1.01-1.22; high: aOR, 1.18; 95% CI, 1.05-1.32) and girls (moderate: aOR, 1.14; 95% CI, 1.05-1.23; high: aOR, 1.30; 95% CI, 1.18-1.42) compared to the low-level dependency group. However, no significant association was found between smartphone usage duration and body image distortion. Conclusion: Our study demonstrated that moderate to high levels of smartphone dependency are associated with body image distortion in adolescents. Therefore, it is necessary to establish strategies for checking and managing adolescents' smartphone dependence.

Controllable SiOx Nanorod Memristive Neuron for Probabilistic Bayesian Inference.

Modern artificial neural network technology using a deterministic computing framework is faced with a critical challenge in dealing with massive data that are largely unstructured and ambiguous. This challenge demands the advances of an elementary physical device for tackling these uncertainties. Here, we designed and fabricated a SiOx nanorod memristive device by employing the glancing angle deposition (GLAD) technique, suggesting a controllable stochastic artificial neuron that can mimic the fundamental integrate-and-fire signaling and stochastic dynamics of a biological neuron. The nanorod structure provides the random distribution of multiple nanopores all across the active area, capable of forming a multitude of Si filaments at many SiOx nanorod edges after the electromigration process, leading to a stochastic switching event with very high dynamic range (≈5.15 × 1010 ) and low energy (≈4.06 pJ). Different probabilistic activation (ProbAct) functions in a sigmoid form are implemented, showing its controllability with low variation by manufacturing and electrical programming schemes. Furthermore, as an application prospect, based on the suggested memristive neuron, we demonstrated the self-resting neural operation with the local circuit configuration and revealed probabilistic Bayesian inferences for genetic regulatory networks with low normalized mean squared errors (≈2.41 × 10-2 ) and its robustness to the ProbAct variation.

Variations of electron flux and microbial community in air-cathode microbial fuel cells fed with different substrates.

Microbial fuel cells (MFCs) can convert chemical energy to electricity using microbes as catalysts and a variety of organic wastewaters as substrates. However, electron loss occurs when fermentable substrates are used because fermentation bacteria and methanogens are involved in electron flow from the substrates to electricity. In this study, MFCs using glucose (G-MFC), propionate (P-MFC), butyrate (B-MFC), acetate (A-MFC), and a mix (M-MFC, glucose:propionate:butyrate:acetate = 1:1:1:1) were operated in batch mode. The metabolites and microbial communities were analyzed. The current was the largest electron sink in M-, G-, B-, and A-MFCs; the initial chemical oxygen demands (COD(ini)) involved in current production were 60.1% for M-MFC, 52.7% for G-MFC, 56.1% for B-MFC, and 68.3% for A-MFC. Most of the glucose was converted to propionate (40.6% of COD(ini)) and acetate (21.4% of COD(ini)) through lactate (80.3% of COD(ini)) and butyrate (6.1% of COD(ini)). However, an unknown source (62.0% of COD(ini)) and the current (34.5% of COD(ini)) were the largest and second-largest electron sinks in P-MFC. Methane gas was only detected at levels of more than 10% in G- and M-MFCs, meaning that electrochemically active bacteria (EAB) could out-compete acetoclastic methanogens. The microbial communities were different for fermentable and non-fermentable substrate-fed MFCs. Probably, bacteria related to Lactococcus spp. found in G-MFCs with fermentable substrates would be involved in both fermentation and electricity generation. Acinetobacter-like species, and Rhodobacter-like species detected in all the MFCs would be involved in oxidation of organic compounds and electricity generation.

Comparison of exoelectrogenic bacteria detected using two different methods: U-tube microbial fuel cell and plating method.

In a microbial fuel cell (MFC), exoelectrogens, which transfer electrons to the electrode, have been regarded as a key factor for electricity generation. In this study, U-tube MFC and plating methods were used to isolate exoelectrogens from the anode of an MFC. Disparate microorganisms were identified depending on isolation methods, despite the use of an identical source. Denaturing gel gradient electrophoresis (DGGE) analysis showed that certain microorganisms became dominant in the U-tube MFC. The predominant bacterium was similar to Ochrobactrum sp., belonging to the Alphaproteobacteria, which was shown to be able to function as an exoelectrogen in a previous study. Three isolates, one affiliated with Bacillus sp. and two with Paenibacillus sp., were identified using the plating method, which belonged to the Gram-positive bacteria, the Firmicutes. The U-tube MFCs were inoculated with the three isolates using the plating method, operated in the batch mode and the current was monitored. All of the U-tube MFCs inoculated with each isolate after isolation from plates produced lower current (peak current density: 3.6-16.3 mA/m(2)) than those in U-tube MFCs with mixed culture (48.3-62.6 mA/m(2)). Although the isolates produced low currents, various bacterial groups were found to be involved in current production.