Microglial activation in the lateral amygdala promotes anxiety-like behaviors in mice with chronic moderate noise exposure.

BACKGROUND: Long-term non-traumatic noise exposure, such as heavy traffic noise, can elicit emotional disorders in humans. However, the underlying neural substrate is still poorly understood. METHODS: We exposed mice to moderate white noise for 28 days to induce anxiety-like behaviors, measured by open-field, elevated plus maze, and light-dark box tests. In vivo multi-electrode recordings in awake mice were used to examine neuronal activity. Chemogenetics were used to silence specific brain regions. Viral tracing, immunofluorescence, and confocal imaging were applied to define the neural circuit and characterize the morphology of microglia. RESULTS: Exposure to moderate noise for 28 days at an 85-dB sound pressure level resulted in anxiety-like behaviors in open-field, elevated plus maze, and light-dark box tests. Viral tracing revealed that fibers projecting from the auditory cortex and auditory thalamus terminate in the lateral amygdala (LA). A noise-induced increase in spontaneous firing rates of the LA and blockade of noise-evoked anxiety-like behaviors by chemogenetic inhibition of LA glutamatergic neurons together confirmed that the LA plays a critical role in noise-induced anxiety. Noise-exposed animals were more vulnerable to anxiety induced by acute noise stressors than control mice. In addition to these behavioral abnormalities, ionized calcium-binding adaptor molecule 1 (Iba-1)-positive microglia in the LA underwent corresponding morphological modifications, including reduced process length and branching and increased soma size following noise exposure. Treatment with minocycline to suppress microglia inhibited noise-associated changes in microglial morphology, neuronal electrophysiological activity, and behavioral changes. Furthermore, microglia-mediated synaptic phagocytosis favored inhibitory synapses, which can cause an imbalance between excitation and inhibition, leading to anxiety-like behaviors. CONCLUSIONS: Our study identifies LA microglial activation as a critical mediator of noise-induced anxiety-like behaviors, leading to neuronal and behavioral changes through selective synapse phagocytosis. Our results highlight the pivotal but previously unrecognized roles of LA microglia in chronic moderate noise-induced behavioral changes.

Transition metals anchored on nitrogen-doped graphdiyne for an efficient oxygen reduction reaction: a DFT study.

The search for highly active and low-cost single-atom catalysts for the oxygen reduction reaction (ORR) is essential for the widespread application of proton exchange membrane fuel cells. Transition metals anchored on nitrogen-doped graphdiyne (GDY) have attracted considerable interest as potentially excellent catalysts for the ORR. However, the relationship between the active site and nitrogen-doped GDY remains unclear. In this work, we conducted a systematic investigation of sp-hybridized N atoms anchoring single transition metal atoms of 3d and 4d on GDY (TMC2N2) as electrocatalysts for the ORR. Firstly, 18 kinds of TMC2N2 were determined to have good thermodynamic stability. Due to the extremely strong adsorption of *OH, TMC2N2 exhibits inferior ORR performance compared to traditional Pt(111). Considering that *OH adsorption hinders the catalytic activity of TMC2N2, we modified the OH ligand of TMC2N2 to develop the high-valent metal complex (TMC2N2-OH) aiming to enhance the electrocatalytic activity. The adsorption of intermediates on most TMC2N2-OH is weakened after the modification of the OH ligand, especially for the adsorption of *OH. Thus, by comparing the ORR overpotential of catalysts before and after ligand modification, we find that the catalytic activity of different TMC2N2-OHs improves to various degrees. MnC2N2-OH, TMC2N2-OH, and TcC2N2-OH exhibit relatively high ORR catalytic activity, with overpotentials of 0.93 V, 1.19 V, and 0.92 V, respectively. Furthermore, we investigated the cause of improved catalytic activity of TMC2N2-OH and found that the modified coordination environment of the catalyst led to adjusted adsorption of ORR intermediates. In summary, our work sheds light on the relationship between nitrogen-doped GDY and transition metal sites, thus contributing to the development of more efficient catalysts.

Characterization of Anxiety-Like Behaviors and Neural Circuitry following Chronic Moderate Noise Exposure in Mice.

BACKGROUND: Commonly encountered nontraumatic, moderate noise is increasingly implicated in anxiety; however, the neural substrates underlying this process remain unclear. OBJECTIVES: We investigated the neural circuit mechanism through which chronic exposure to moderate-level noise causes anxiety-like behaviors. METHODS: Mice were exposed to chronic, moderate white noise [85 decibel (dB) sound pressure level (SPL)], 4 h/d for 4 wk to induce anxiety-like behaviors, which were assessed by open field, elevated plus maze, light-dark box, and social interaction tests. Viral tracing, immunofluorescence confocal imaging, and brain slice patch-clamp recordings were used to characterize projections from auditory brain regions to the lateral amygdala. Neuronal activities were characterized by in vivo multielectrode and fiber photometry recordings in awake mice. Optogenetics and chemogenetics were used to manipulate specific neural circuitry. RESULTS: Mice chronically (4 wk) exposed to moderate noise (85 dB SPL, 4 h/d) demonstrated greater neuronal activity in the lateral amygdala (LA), and the LA played a critical role in noise-induced anxiety-like behavior in these model mice. Viral tracing showed that the LA received monosynaptic projections from the medial geniculate body (MG) and auditory cortex (ACx). Optogenetic excitation of the MG→LA or ACx→LA circuits acutely evoked anxiety-like behaviors, whereas their chemogenetic inactivation abolished noise-induced anxiety-like behavior. Moreover, mice chronically exposed to moderate noise were more susceptible to acute stress, with more neuronal firing in the LA, even after noise withdrawal. DISCUSSION: Mice exposed to 4 wk of moderate noise (85 dB SPL, 4 h/d) demonstrated behavioral and physiological differences compared to controls. The neural circuit mechanisms involved greater excitation from glutamatergic neurons of the MG and ACx to LA neurons under chronic, moderate noise exposure, which ultimately promoted anxiety-like behaviors. Our findings support the hypothesis that nontraumatic noise pollution is a potentially serious but unrecognized public health concern. https://doi.org/10.1289/EHP12532.

Unraveling the effect of CDI electrode characteristics on Cs removal from the perspective of ion transfer and energy composition.

Capacitive deionization (CDI) is surprisingly efficient to remove the aqueous Cs ion due to its small hydrated size and low hydration energy. But current experimental techniques fail in investigating deeply into the influence of some key electrode characteristics due to the difficulty in experimentally fabricating the electrodes as desired. This work presents a dynamic transport model of salt ions in a flow-by CDI cell. By using this model, the electrode thickness, macro- and micro-porosity are investigated to evaluate Cs ion removal efficiency and energy efficiency particularly from the aspect of ion transfer by the approach of decomposing energy contribution. The results indicate that the thick electrode coupled with the high current could greatly improve the effluent quality, but reduce the salt adsorption capacity (SAC). The increasement of the current density from 3 A/m2 to 6 A/m2 greatly decreases the SAC from 4.0 mg/g to 0.8 mg/g. Lower current could prolong the charging period, leading to more ions stored in the micropore. Not all the electrical energy is consumed for separating ions from the feed as desired, but some are used for driving ions diffusing in the electrodes. Consequently charging efficiency will be reduced especially when the electrodes are characterized with high porosity. It is highlighted that future work is required to further consider the complex details of porous structure and pore connectivity.

Diffusion Behavior of VOC Molecules in Polyvinyl Chloride Investigated by Molecular Dynamics Simulation.

Due to the threats posed by many volatile organic compounds (VOCs) to human health in indoor spaces via air, the mass transfer characteristics of VOCs are of critical importance to the study of their mechanism and control. As a significant part of the mass transfer process, diffusion widely exists in emissions from floors (e.g., PVC floors) and in sorption in porous materials. Molecular simulation studies by can provide unparalleled insights into the molecular mechanisms of VOCs. We construct the detailed atomistic structures of PVC blend membranes to investigate the diffusion behavior of VOC molecules (n-hexane) in PVC by molecular dynamics (MD). The variation in the diffusion coefficient of n-hexane in PVC with respect to temperature is in line with Arrhenius' law. The effect of temperature on the diffusion mechanism was investigated from the perspectives of free volume, cavity distribution and polymer chain mobility. It was found that the relationships between the diffusion coefficients of n-hexane in the polymer and the inverse fractional free volume are exponential and agree well with the free volume theory. Hopefully, this study will offer quantitative insights into the mass transport phenomena of VOCs within polymeric materials.

Non-Covalent Bond-Regulated Solar Evaporation Modulator: Facilitative Hydration Domains Originated via a Homogeneous Polymeric Network.

The solar-driven evaporation technology provides a green alternative for solving water scarcity. However, it remains challenging to improve the steam conversion efficiency due to the difficulties in simultaneously coordinating light absorbance, water regulation, and thermal management for broadband solar evaporators. Here, an unconventional solar evaporative modulator material─ultra-interfacial adherent dimethyl sulfoxide polyvinyl alcohol (DMSO-PVA) hydrogel (DPH) was presented. The material is based on the regulation of the PVA-PVA intra- and PVA-water interchain hydrogen bonds by DMSO, which established an adaptive high-cross-linking and homogeneous network. The consequent ultra-thin hydrogel exploited an insulating polymer backbone and intracavity hydration domain to simultaneously improve the light absorption and thermal localization and activate the water molecule. As a proof-of-concept, under 1 sun illumination (1 kW m-2), a DPH-based graphene fiber membrane [ultra-thin hydrogel membrane (UHM)] achieved 97% light absorption, 2.33 kg m-2 h-1 water evaporation, and high salt-resistant evaporation (1.48 kg m-2 h-1 under 25 wt % brine). Compared to the pure graphene membrane, UHM increased the vaporization by 64%, decreased the heat diffusion by over 14-folds, and reduced the environmental heat loss by 2.6-folds. DPH possesses scalability and versatility in bridging nanoscale photothermal materials and solar evaporator geometric architecture and will facilitate the possibility of advanced solar thermal applications.

Precise manipulation of the charge percolation networks of flow-electrode capacitive deionization using a pulsed magnetic field.

Magnetic field is a simple and powerful means that enables controlled the transport of electrode particles in flow electrode capacitive deionization (FCDI). However, the magnetic particles are easily stripped from hybrid suspension electrodes and the precise manipulation of the charge percolation network remains challenging. In this study, a programmable magnetic field was introduced into the FCDI system to enhance the desalination performance and operational stability of magnetic FCDI, with core-shell magnetic carbon (MC) used as an alternative electrode additive. The results showed that the pulsed magnetic field (PMF) was more effective in enhancing the average salt removal rate (ASRR) compared to the constant magnetic field (CMF), with 51.6% and 67.7% enhancement, respectively, compared to the magnetic field-free condition. The outstanding advantage of the PMF lies in the enhancement in the trapping and mediating effects in the switching magnetic field, which keeps the concentration of the electrode particles near the current collector at a high level and greatly facilitates electron transport. In long-term operation (20,000 cycles), the pulsed magnetic FCDI achieved a stable desalinating rate of 0.4-0.68 µmol min-1 cm-2 and a charge efficiency of >96%. In brief, our study introduces a new approach for the precise manipulation of charge percolation networks of the suspension electrodes and provides insight into the charging mechanism of the magnetic FCDI.

Enhancing Brackish Water Desalination using Magnetic Flow-electrode Capacitive Deionization.

Flow-electrode capacitive deionization (FCDI) is viewed as a potential alternative to the current state-of-the-art electrodriven technology for the desalination of brackish water. However, the key shortcoming of the FCDI is still the discontinuous nature of the electrode conductive network, resulting in low electron transport efficiency and ion adsorption capacity. Here, a novel magnetic field-assisted FCDI system (termed magnetic FCDI) is proposed to enhance brackish water desalination, simply by using magnetic activated carbon (MAC) as flow electrodes. The results show that the assistance from the magnetic field enables a 78.9% - 205% enhancement in the average salt removal rate (ASRR) compared with that in the absence of a magnetic field, which benefits from the artificial manipulation of the flow electrode transport behavior. In long-term tests, the stable desalination performance of magnetic FCDI was also demonstrated with a stable ASRR of 0.70 µmol cm-2 min-1 and energy-normalized removed salt (ENRS) of 8.77 µmol J-1. In addition, magnetic field also enables the regeneration of the electrode particles from the concentrated electrolyte. In summary, the findings indicate that the magnetic FCDI is an energy-efficient and operation convenient technology for brackish water desalination.

Membrane-Current Collector-Based Flow-Electrode Capacitive Deionization System: A Novel Stack Configuration for Scale-Up Desalination.

The stack configuration in flow-electrode capacitive deionization (FCDI) has been verified to be an attractive and feasible strategy for scaling up the desalination process. However, challenges still exist when attempting to simultaneously improve the desalination scale and the cell configuration. Here, we describe a novel stack FCDI configuration (termed a gradient FCDI system) based on a membrane-current collector assembly, in which the charge neutralization enables the in situ regeneration of the flow electrodes in the single cycle operation, thereby realizing a considerable increase in the desalinating performance. By evaluating standardized metrics such as the salt rejection, productivity (P), average salt removal rate (ASRR), energy-normalized removed salt (ENRS), and TEE, the results indicated that the gradient FCDI system could be a performance-stable and energy-efficient alternative for scale-up desalination. Under optimal operating conditions (carbon content = 10 wt %, feed salinity = 3000 mg L-1, cell voltage = 1.2 V, and productivity = 56.7 L m-2 h-1), the robust desalination performance (ASRR = 1.07 µmol cm-2 min-1) and energy consumption (ENRS = 7.8 µmol J-1) of the FCDI system with a desalination unit number of four were verified at long-term operation. In summary, the stacked gradient FCDI system and its operation mode described here may be an innovative and promising strategy capable of enlarging the scale of desalination while realizing performance improvement and device simplification.

Selective recovery of phosphorus and urea from fresh human urine using a liquid membrane chamber integrated flow-electrode electrochemical system.

Phosphorus (P) extraction from human urine is a potential strategy to address global resource shortage, but few approaches are able to obtain high-quality liquid P products. In this study, we introduced an innovative flow-electrode capacitive deionization (FCDI) system, also called ion-capture electrochemical system (ICES), for selectively extracting P and N (i.e., urea) from fresh human urine simply by integrating a liquid membrane chamber (LMC) using a pair of anion exchange membrane (AEM). In the charging process, negatively charged P ions (i.e., HPO42- and H2PO4-) can be captured by acidic extraction solutions (e.g., solutions of HCl, HNO3 and H2SO4) on their way to the anode chamber, leading to the conversion of P ions to uncharged H3PO4, while other undesired ions such as Cl- and SO42- are expelled. Simultaneously, uncharged urea molecules remain in the urine effluent with the removal of salt. Thus, high-purity phosphoric acid and urea solutions can be obtained in the LMC and spacer chambers, respectively. The purification of P in an acidic environment is ascribed largely to the competitive migration and protonation of ions. The latter contributes ~27% for the selective capture of P. Under the optimal operating conditions (i.e., ratio of the urine volume to the HCl volume = 7:3, initial pH of the extraction solution = 1.43, current density = 20 A/m2 and threshold pH ~ 2.0), satisfactory recovery performance (811 mg/L P with 73.85% purity and 8.3 g/L urea-N with 81.4% extraction efficiency) and desalination efficiency (91.1%) were obtained after 37.5 h of continuous operation. Our results reveal a promising strategy for improving in selective separation and continuous operation via adjustments to the cell configuration, initiating a new research dimension toward selective ion separation and high-quality P recovery.

Uncertainty Quantification Guided Parameter Selection in a Fully Coupled Molecular Dynamics-Finite Element Model of the Mechanical Behavior of Polymers.

The objective of investigating macroscopic polymer properties with a low computing cost and a high resolution has led to the development of efficient hybrid simulation tools. Systems generated from such simulation tools can fail in service if the effect of uncertainty of model inputs on its outputs is not accounted for. This work focuses on quantifying the effect of parametric uncertainty in our coarse-grained molecular dynamics-finite element coupling approach using uncertainty quantification. We consider uniaxial deformation simulations of a polystyrene sample at T = 100 K in our study. Parametric uncertainty is assumed to originate from parameters in the molecular dynamics model with a nonperiodic boundary (the force constant between polymer beads and anchor points, the number of anchor points, and the size of the surrounding dissipative particle dynamics domain) and a parameter to blend the energies of particles and continuum (weighting factor). Key issues that arise in uncertainty quantification are discussed on the basis of the quantities of interest including mass density, end-to-end distance, and radial distribution function. This work reveals the influence of key input parameters on the properties of polymer structure and facilitates the determination of those parameters in the application of this hybrid molecular dynamics-finite element approach.

Scale-up desalination: Membrane-current collector assembly in flow-electrode capacitive deionization system.

Salt removal from seawater/wastewater using flow-electrode capacitive deionization (FCDI) is of particular interest, but scale-up desalination is limited by low water production, high energy consumption and complex cell configuration. In this study, an innovative FCDI system is described that uses integrated desalination modules equipped with membrane-current collector (MCC) assembly, and thereby named as MCC-FCDI system. A single desalination module design provides an average salt removal rate (ASRR, 0.3 - 0.44 µmol/(cm2·min)) close to that of the classic FCDI system (with a graphite current collector design), but the design requires a much lower infrastructure investment, device size and energy cost. More importantly, our design enables simultaneous operation of multiple modules in the shared flow-electrode tank, easily realizing scale-up desalination. Evidence is provided by the results of the multi-module operation: multi-modules isolated closed-cycle (MICC) and multi-modules short-circuited closed-cycle (MSCC). For instance, the MICC configuration showing nearly twice the desalination performance over ~ 50 h of operation compared to that of the single ICC operation. The results indicated that in addition to making the device suitable for practical application, the Ti-mesh MCC with a woven network enables the flow electrode to achieve substantial ion adsorption capacity due to the efficient update of fresh carbon particles. In short, the results of this study showed that MCC-FCDI is a promising desalination system for scale-up applications, providing a new reference and guidance for device design.

Can flow-electrode capacitive deionization become a new in-situ soil remediation technology for heavy metal removal?

In this study, we present a novel soil electrochemical remediation technology (called S-FCDI), which is based on flow-electrode capacitive deionization (FCDI), for Cd removal from kaolin while under continuous operation mode. The results demonstrated that Cd can be effectively removed from kaolin with reasonable energy consumption and minimal macroelement loss. The carboxylic (OOH) functional groups on the surface of activated carbon (AC) facilitated the transfer of Cd from kaolin onto carbon surface. A stable acidic environment, which is advantageous for continuous Cd desorption, was achieved as a result of the balance between H+ generation and transmembrane migration. Once these net negative charges on the particle were eliminated or reversed, the adsorbed Cd could be released easily and driven in concentrated stream by electrostatic repulsion. Under the optimal operating conditions (i.e., carbon =50 g/L, j = 3.47 A/m2, pHi = 3.2, [NaCl]a =8.6 mmol/L), more than 80 % Cd was removed from (200 g) kaolin after continuous 19 h operation at a relatively low electricity consumption of 22.7 kW h/kg Cd and a limited Al loss of 0.06 wt‰. These results from this work demonstrated that S-FCDI could be an alternative soil electrochemical remediation technology for heavy metal removal with low soil damage.

Unraveling the Overlooked Involvement of High-Valent Cobalt-Oxo Species Generated from the Cobalt(II)-Activated Peroxymonosulfate Process.

Sulfate radical (SO4•-) is widely recognized as the predominant species generated from the cobalt(II)-activated peroxymonosulfate (PMS) process. However, in this study, it was surprisingly found that methyl phenyl sulfoxide (PMSO) was readily oxidized to the corresponding sulfone (PMSO2) with a transformation ratio of ∼100% under acidic conditions, which strongly implied the generation of high-valent cobalt-oxo species [Co(IV)] instead of SO4•- in the Co(II)/PMS process. Scavenging experiments using methanol (MeOH), tert-butyl alcohol, and dimethyl sulfoxide further suggested the negligible role of SO4•- and hydroxyl radical (•OH) but favored the generation of Co(IV). By employing 18O isotope-labeling technique, the formation of Co(IV) was conclusively verified and the oxygen atom exchange reaction between Co(IV) and H2O was revealed. Density functional theory calculation determined that the formation of Co(IV) was thermodynamically favorable than that of SO4•- and •OH in the Co(II)/PMS process. The generated Co(IV) species was indicated to be highly reactive due to the existence of oxo-wall and capable of oxidizing the organic pollutant that is rather recalcitrant to SO4•- attack, for example, nitrobenzene. Additionally, the degradation intermediates of sulfamethoxazole (SMX) in the Co(II)/PMS process under acidic conditions were identified to further understand the interaction between Co(IV) and the representative contaminant. The developed kinetic model successfully simulated PMSO loss, PMSO2 production, SMX degradation, and/or PMS decomposition under varying conditions, which further supported the proposed mechanism. This study might shed new light on the Co(II)/PMS process.

Activation of dissolved molecular oxygen by Cu(0) for bisphenol a degradation: Role of Cu(0) and formation of reactive oxygen species.

In this study, Cu(0) was synthesized with NaBH4 as a reducing agent for Cu(II) and used to activate dissolved molecular oxygen (O2) under acidic conditions. The Cu(0) synthesized had much higher activity than the purchased. The roles of Cu was clarified and the formation of reactive oxygen species was discussed through direct detection for the first time. By detecting the valence change of Cu in a CuO system, Bisphenol A (BPA) was found to accelerate the transformation of Cu(II) to Cu(I). Besides, the evidence from electron spin resonance (ESR) studies and scavenging tests revealed the new roles of Cu(0) that Cu(0) could not only convert O2 to produce ·O2-, but also catalyze H2O2 to ·OH. The results from this study offer evidence of new reaction pathways in Cu-activated O2 systems and deepen understanding of the reaction between Cu species and O2.

Evaluation of the effects of low-impact development practices under different rainy types: case of Fuxing Island Park, Shanghai, China.

The soil permeability and underground water level greatly affect the performance of low-impact development (LID) practices. Shanghai is located in the area of estuary and is characterized by its high groundwater level and low soil infiltration rate. The LID practices in Fuxing Island Park, Shanghai, including a bioretention cell, swales, a permeable pavement, and a combined LID practices were studied in the present paper. The performance of LID practices during the period of eight rainfall events was evaluated in terms of hydrology and water quality. Due to the detention of the LID practices, a significant delay between the peak rainfall and the peak surface runoff was observed. On-site tests show it is suitable for the applicability of LID in a rainy city with low soil infiltration rate and high groundwater level. Moreover, the Stormwater Management Model (SWMM) was also used to compare the hydrologic effects before and after these four LID practices application in the park. Results indicated the LID practices could effectively reduce the runoff volume and the peak flow in the park. Furthermore, the runoff water quality evaluation showed the pollutants were effectively removed by these four LID practices due to both runoff treatment and flow volume reduction. The bioretention system proved to be effective as a result of its larger facility area while the swales had the obvious reduction volume both per facility area and per catchment area.