Charge Region Research Articles

Achieving Dendrite‐Free Lithium Metal Batteries by Constructing a Dense Lithiophilic Cu1.8Se/CuO Heterojunction Tip

AbstractLithium (Li) metal batteries (LMBs) have garnered widespread attention due to their high specific capacity. However, the growth of lithium dendrite severely limits their practical applications. Herein, a novel strategy is proposed to regulate the overall potential strength and lithium ions (Li+) concentration on the surface of the current collector by utilizing densely distributed tip effects. This concept is exemplified through the construction of lithiophilic Cu1.8Se/CuO heterojunction needle array on the Cu foil, ultimately achieving dendrite‐free lithium deposition. Based on the simulation in COMSOL multiphysics and experimental research, this design is demonstrated to enrich Li+ on the current collector surface, delay the formation of space charge regions, and mitigate the growth of lithium dendrites. Additionally, a built‐in electric field (BIEF) triggered by the heterointerface between Cu1.8Se and CuO further alleviates the Li+ concentration gradient on the electrode surface, achieving uniform bottom‐up deposition of Li within the array structure. Consequently, the symmetrical cell exhibits an ultra‐long cycle life of 2400 h (1 mA cm−2, 1 mAh cm−2) with an extremely low overpotential of 13 mV. Furthermore, full batteries using LiFePO4 as the cathode exhibit superior cycle stability and rate performance. This study presents a promising approach for designing dendrite‐free current collectors in LMBs.

Exploring the orphan immune receptor TREM2 and its non-protein ligands: In silico characterization

The triggering receptor expressed on myeloid cells 2 (TREM2) is an immunoreceptor that interacts with a wide range of non-protein ligands, and it has been implicated in infectious and non-infectious diseases. However, there is a limited understanding on how this receptor interacts with non-protein ligands and the potential of such information to develop new therapeutic drugs. Therefore, our study aimed to elucidate the interactions between TREM2 and its non-protein ligands. First, we searched PubChem and Protein Data Bank (PDB) for TREM2 structures and their corresponding non-protein ligands. Subsequently, these structures were employed in molecular docking and MM/GBSA simulations with the Maestro software and molecular dynamics in GROMACS software. TREM2 was subsequently subjected to druggable site prediction using CavityPlus and receptor-based drug repositioning via the DrugRep server. TREM2 interacts with high affinity with its 12 non-protein ligands, with affinity values ranging from −33.01 kcal/mol for phosphatidylserine to −80.87 kcal/mol for cardiolipin (CLP). In molecular dynamics simulations, homodimeric TREM2 bound more stably to its lipid ligands, such as CLP and PSF, whereas it was unstable when unbound. The interactions between the receptor and its non-protein ligands were driven by the complementarity determining regions (CDR) 1 and 2, that are present in the hydrophobic and positively charged regions, highlighting that the Y38–R98 region is fundamental for drugs targeting TREM2. Our data underscore the significance of TREM2's CDRs in recognizing its ligands, suggesting they as promising targets for prospective drug design studies.

The prolyl isomerase FKBP11 is a secretory translocon accessory factor.

Eukaryotic cells encode thousands of secretory and membrane proteins, many of which are cotranslationally translocated into or across the endoplasmic reticulum (ER). Nascent polypeptides entering the ER encounter a network of molecular chaperones and enzymes that facilitate their folding. A rate-limiting step for some proteins is the trans-to-cis isomerization of the peptide bond between proline and the residue preceding it. The human ER contains six prolyl isomerases, but the function, organization and substrate range of these proteins is not clear. Here we show that the metazoan-specific, prolyl isomerase FKBP11 binds to ribosome-translocon complexes (RTCs) in the ER membrane, dependent on its single transmembrane domain (TMD) and a conserved, positively charged region at its cytosolic C-terminus. High throughput mRNA sequencing shows selective engagement with ribosomes synthesizing secretory and membrane proteins with long translocated segments, and functional analysis shows reduced stability of two such proteins, EpCAM and PTTG1IP, in cells depleted of FKBP11. We propose that FKBP11 is a translocon accessory factor that acts on a broad range of soluble secretory and transmembrane proteins during their synthesis at the ER.

Development of Semi-Empirical and Machine Learning Models for Photoelectrochemical Cells

We introduce a theoretical model for the photocurrent-voltage (I-V) characteristics designed to elucidate the interfacial phenomena in photoelectrochemical cells (PECs). This model investigates the sources of voltage losses and the distribution of photocurrent across the semiconductor–electrolyte interface (SEI). It calculates the whole exchange current parameter to derive cell polarization data at the SEI and visualizes the potential drop across n-type cells. The I-V model’s simulation outcomes are utilized to distinguish between the impacts of bulk recombination and space charge region (SCR) recombination within semiconductor cells. Furthermore, we develop an advanced deep neural network model to analyze the electron–hole transfer dynamics using the I-V characteristic curve. The model’s robustness is evaluated and validated with real-time experimental data, demonstrating a high degree of concordance with observed results.

Constructing Quasi-Single Ion Conductors by a β-Cyclodextrin Polymer to Stabilize Zn Anode.

Aqueous Zn-ion batteries (AZIBs) are promising for the next-generation large-scale energy storage. However, the Zn anode remains facing challenges. Here, we report a cyclodextrin polymer (P-CD) to construct quasi-single ion conductor for coating and protecting Zn anodes. The P-CD coating layer inhibited the corrosion of Zn anode and prevented the side reaction of metal anodes. More important is that the cyclodextrin units enabled the trapping of anions through host-guest interactions and hydrogen bonds, forming a quasi-single ion conductor that elevated the Zn ion transference number (from 0.31 to 0.68), suppressed the formation of space charge regions and hence stabilized the plating/striping of Zn ions. As a result, the Zn//Zn symmetric cells coated with P-CD achieved a 70.6 times improvement in cycle life at high current densities of 10 mA cm-2 with 10 mAh cm-2. Importantly, the Zn//K1.1V3O8 (KVO) full-cells with high mass loading of cathode materials and low N/P ratio of 1.46 reached the capacity retention of 94.5 % after 1000 cycles at 10 A g-1; while the cell without coating failed only after 230 cycles. These results provide novel perspective into the control of solid-electrolyte interfaces for stabilizing Zn anode and offer a practical strategy to improve AZIBs.

Constructing Quasi‐Single Ion Conductors by a β‐Cyclodextrin Polymer to Stabilize Zn Anode

AbstractAqueous Zn‐ion batteries (AZIBs) are promising for the next‐generation large‐scale energy storage. However, the Zn anode remains facing challenges. Here, we report a cyclodextrin polymer (P‐CD) to construct quasi‐single ion conductor for coating and protecting Zn anodes. The P‐CD coating layer inhibited the corrosion of Zn anode and prevented the side reaction of metal anodes. More important is that the cyclodextrin units enabled the trapping of anions through host–guest interactions and hydrogen bonds, forming a quasi‐single ion conductor that elevated the Zn ion transference number (from 0.31 to 0.68), suppressed the formation of space charge regions and hence stabilized the plating/striping of Zn ions. As a result, the Zn//Zn symmetric cells coated with P‐CD achieved a 70.6 times improvement in cycle life at high current densities of 10 mA cm−2 with 10 mAh cm−2. Importantly, the Zn//K1.1V3O8 (KVO) full‐cells with high mass loading of cathode materials and low N/P ratio of 1.46 reached the capacity retention of 94.5 % after 1000 cycles at 10 A g−1; while the cell without coating failed only after 230 cycles. These results provide novel perspective into the control of solid‐electrolyte interfaces for stabilizing Zn anode and offer a practical strategy to improve AZIBs.

Circuit Modeling of the Impact of Heavy Charged Particles on Transient Processes in Bipolar Analog Microcircuits

One of the factors causing the failure of spacecraft integrated circuits is exposure to heavy charged particles. The entry of heavy charged particles into electronic devices leads to the appearance of single event transients (short current pulses), which in analog microcircuits manifest themselves in distortion of the output signal shape, and in digital microcircuits can cause a single event upset. The article discusses a technique for circuit mode-ling of the effect of heavy charged particles on bipolar analog microcircuits, including the developed equivalent electrical circuit of a bipolar transistor for LTSpice and the procedure for modeling transient processes. Despite the simplifications adopted, namely: failure to take into account the dependence of the duration of the rise and fall of the current pulse generated by a charged particle on the parameters of the transistor structure, the assumption that the entire charge is generated in the active base and the space charge regions of the emitter and collector junctions, an equivalent circuit has been developed made it possible to determine that the shape of the collector current pulse for circuit with a common emitter when exposed to a heavy charged particle is determined by the speed of the transistor and its operating mode. Using the developed methodology, the “critical” transistors of the two studied analog microcircuits were determined, and the need to bypass the current-setting resistors with a small capacitor was justified.

Fabrication of heterostructure multilayer devices through the optimization of Bi-metal sulfides for high-performance quantum dot-sensitized solar cells.

In this work, a titanium dioxide and lead sulfide (TiO2/PbS) nano-size heterostructure with tin sulfide was fabricated and coated via a two-step direct deposition process. Its microstructure, morphology, elemental composition, optical absorption, and photochemical activity were investigated. Linear sweep voltammetry and cyclic voltammetry curves substantiated its catalytic activity, indicating quantum dot effects of a well-developed space charge domain on the surface of the hybrid structure. These give rise to electron-hole recombination suppression and a high charge mobility rate. Moreover, direct stabilization was identified in current density, corresponding to the hybrid structures limiting the diffusion current process. Higher J SC values observed were substantiated by the role of quantum dot-size effects and enhanced crystalline structures, leading to a reduction in series resistance and an improved conversion efficiency of 10.05%. Overall, theoretical analyses and empirical findings indicated that the seamless migration of photoexcited electrons across the interfaces of SnS and PbS is linked to quantum dot effect synergy. This is facilitated by the space charge region, which serves as a conduit for efficient electron transfer between the respective materials.

High‐Gain and Tunable Linear Photodetection in 2D Tunneling Heterostructures Through Potential Engineering

Abstract2D materials are extensively employed in the fabrication of high‐performance photodetectors owing to their exceptional physical properties. However, most 2D material photodetectors fail to sustain high gain under intense illumination due to the limited intrinsic trap states. Here, an n‐n type Bi2O2Se/SnSe2 van der Waals tunneling heterojunction photodetector with a detection range from visible to near‐infrared (VIS‐NIR) is presented. Under reverse bias, the heterojunction induces a significant electron barrier and hole potential well, ensuring low leakage current and ample hole defect states. Therefore, the photodetector demonstrated a responsivity of 1636.3 AW−1 and a detectivity of 1.39 × 1014 Jones under 660 nm illumination, maintaining a tunable linear dynamic range (LDR) of ≈74.7 dB. This performance is attributed to the hole potential well‐suppressing the recombination of photogenerated carriers, thereby enhancing the device's gain. Furthermore, the tunneling of photogenerated electrons within the heterojunction's space charge region under bias enables rapid response (75.1 and 15.6 µs). In summary, the study introduces a novel strategy to overcome the limited detection capabilities of 2D devices under intense illumination, characterized by outstanding linearity for rapid detection and high‐resolution imaging.

Increasing the Efficiency of Thermoelectric Conversion of Solar Energy

The article considers the latest achievements in the field of thermionic conversion of solar energy. The key aspects of thermionic emission, the problems of reducing the electrode work function and increasing the efficiency of devices are analyzed. It is shown that diamonds doped with phosphorus can be an attractive material for the purposes of thermionic emission. In this case, the presence of donor states can significantly narrow the space charge region, and at the same time reduce the potential barrier in the work function. The studies also found that the most successful and widely used method for overcoming the space charge effect is filling the interelectrode gap with cesium. The efficiency of thermionic conversion devices for solar energy increases by 1.6 times. Particular attention is paid to the use of new materials, such as nanostructures and carbon nanotubes, as well as promising technologies, such as photonic enhancement of thermionic processes. The analysis of the results showed that the photonic enhancement of the electron yield due to illumination is greater in p-type silicon, as predicted by theoretical models. The thermionic current increases by 1.7 times compared to silicon. The distance between the quasi-Fermi level and the Fermi level in n-type silicon is less than this distance in p-type silicon. As a consequence, the number of electrons in the conduction band is smaller. Methods for combating the space charge effect and optimizing the configuration of energy conversion systems are discussed.

Observation of Electrical Alignment Signatures in an Isolated Thunderstorm by Dual‐Polarized Phased Array Weather Radar and the Relationship With Intracloud Lightning Flash Rate

AbstractThe electrical alignment signatures of ice crystals in the middle and upper parts of a thunderstorm have a physical connection with the strong electric fields within the cloud. By taking advantage of the high spatio‐temporal resolution of an X‐band dual‐polarized multiparameter phased array radar, this paper employs negative KDP signatures to investigate the variation of electric fields in an isolated thunderstorm within its evolution, and the relationship between the negative KDP signatures and intracloud (IC) lightning activity. The results show that the radar‐inferred strong electric fields distributed in a region of about 8.5–10 km during the developing stage, then extended from about 10 km to the cloud top during the mature stage, with an increasing IC lightning flash rate before the end of the mature stage. Subsequently, the electric fields weakened associated with a large amount of IC lightning discharges. The qualitative analysis results indicate that the evolution of the radar‐inferred electric fields associated with the upper charge regions is consistent with the electrification process in the isolated thunderstorm, inferred by the IC lighting activity. In addition, there is a tendency for the increased IC lightning rate as the decrease in average composite KDP in the middle and upper layers of the thunderstorm, with a time lag of about 5.5 min between the minimum average composite KDP and the peak IC lightning rate, while a good correlation between the negative KDP volume and the IC lightning flash rate at a lag of approximately 9 min.

Targeted no-releasing L-arginine-induced hesperetin self-assembled nanoparticles for ulcerative colitis intervention

Overproduction of reactive oxygen species (ROS) plays a crucial role in initiating and advancing ulcerative colitis (UC), and the persistent cycle between ROS and inflammation accelerates disease development. Therefore, developing strategies that can effectively scavenge ROS and provide targeted intervention are crucial for the management of UC. In this study, we synthesized natural carrier-free nanoparticles (HST-Arg NPs) using the Mannich reaction and π-π stacking for the intervention of UC. HST-Arg NPs are an oral formulation that exhibit good antioxidant capabilities and gastrointestinal stability. Benefiting from the negatively charged characteristics, HST-Arg NPs can specifically accumulate in positively charged inflamed regions of the colon. Furthermore, in the oxidative microenvironment of colonic inflammation, HST-Arg NPs respond to ROS by releasing nitric oxide (NO). In mice model of UC induced by dextran sulfate sodium (DSS), HST-Arg NPs significantly mitigated colonic injury by modulating oxidative stress, lowering pro-inflammatory cytokines, and repairing intestinal barrier integrity. In summary, this convenient and targeted oral nanoparticle can effectively scavenge ROS at the site of inflammation and achieve gas intervention, offering robust theoretical support for the development of subsequent oral formulations in related inflammatory interventions. Statement of significanceNanotechnology has been extensively explored in the biomedical field, but the application of natural carrier-free nanotechnology in this area remains relatively rare. In this study, we developed a natural nanoparticle system based on hesperetin (HST), L-arginine (L-Arg), and vanillin (VA) to scavenge ROS and alleviate inflammation. In the context of ulcerative colitis (UC), the synthesized nanoparticles exhibited excellent intervention effects, effectively protecting the colon from damage. Consequently, these nanoparticles provide a promising and precise nutritional intervention strategy by addressing both oxidative stress and inflammatory pathways simultaneously, demonstrating significant potential for application.

E242-E261 region of MYC regulates liquid-liquid phase separation and tumor growth by providing negative charges

MYC is one of the most extensively studied oncogenic proteins and is closely associated with the occurrence and progression of many tumors. Previous studies have shown that MYC regulates cell fate through its liquid-liquid phase separation (LLPS) mechanism, which is dependent on two disordered domains within its N-terminal transcriptional activation regions. In this study, we revealed that the negatively charged conserved region (E242-E261) of the MYC protein controls its condensation formation and irreversible aggregation through multivalent electrostatic interactions (MEIs). Furthermore, deletion or mutation of the E242-E261 amino acids in the MYC protein enhances the transcriptional function of MYC by altering its aggregation capacity and subsequently promoting cancer cell proliferation. The discovery of the negatively charged region and its regulatory action on the phase separation of MYC provides a new understanding on the aggregation and function of MYC.

Structural features of carrot α-tubulin predetermining the natural resistance to dinitroaniline herbicides

Aim. To explain the natural resistance of Daucus carota L. to dinitroaniline herbicides. To clarify features of the carrot α-tubulin that may affect formation of the ligand-protein complex based on the structural and electrostatic analysis of the ligand-binding site. Methods. Reconstruction of the spatial structure of α-tubulin from D. carota and Toxoplasma gondii using profile (Swiss-Model) and de-novo (AlphaFold2) modeling. Molecular dynamics (MD) simulations of the built 3D-models in Gromacs. Analysis of the molecular electrostatics with PDB2PQR/APBS tools. Visualization and analysis of molecular structures in PyMOL. Results. It has been shown that along with the typical positive charge of the dinitroaniline-binding pocket, all isotypes of carrot α-tubulin demonstrate negatively charged regions that may cause conflicts with the nitro-groups of the ligands. Also, the MD-stable negatively charged "bridge" between Cys316 and the aryl-fragment of Phe255 was observed in all α-tubulin isotypes. In our opinion, it not only competes with the cyclic fragment of dinitroanilines, but overall prevent the opening of the site pocket in carrot α-tubulin. Conclusions. It was clarified that natural resistance of D. carota to dinitroaniline herbicides may be associated with steric and electrostatic conflicts observed in in all α-tubulin isotypes. In our opinion, it prevents interaction with dinitroaniline compounds at the stage of primary site recognition on the early stages of protein-ligand complex formation.

A niobium and tantalum co-doped perovskite electrolyte with high ionic conduction for low-temperature Ceramics Fuel cell

In recent studies, fast ionic conduction through surface doping and coating has been a favorite subject and has indicated a promising and stable strategy to optimize ions in the developed electrolytes for low-temperature ceramic fuel cells (LT-CFCs). We have designed co-doped perovskite (Nb/Ta-SrCoO3) to enhance further ionic properties using the Solid-state blending technique. The prepared SCNT (SrCoNb0.3Ta0.3O3) was used as an electrolyte sandwiched between symmetrical electrodes and delivered attractive fuel cell performance (650 mW/cm2) with better stability at the low operating temperature of 520 °C compared to other compositions of SCNT. The low grain boundary resistance manifests SCNT's high ionic conduction + microstructural properties, assisting with higher fuel cell performance. The co-doping enables the fermi-level to move towards the -ive side, establishing a space charge region constituting BIEF (built in electric field) and helping to enhance the ions' transportation through the surface and interface. This work thus points out a new type of electrolyte with a different working mechanism from previous studies. It indicates a feasible approach to developing high-performing and stable electrolytes for LT-CFCs.

Designing a hollow MoSe2/CuS nanospheres type-II heterojunction photocatalyst with superior UV-vis-NIR absorption for photocatalytic degradation of organic pollutants.

In this work, a hollow MoSe2/CuS type-II heterojunction was fabricated using hollow MoSe2 nanospheres as the basis for structural design. UV-Vis-NIR diffuse absorption tests show that MoSe2/CuS has a broad spectral absorption to extend the optical response range from UV-Vis to NIR. The light source utilization rate and interfacial area are increased by the hollow MoSe2/CuS core-shell structure. The broad absorption ability of MoSe2/CuS can facilitate the photocatalysis process. As the electrochemical impedance of MoSe2/CuS is lower than that of the MoSe2, MoSe2/CuS has a good photogenerated carrier separation efficiency. Benefiting from the synergistic facilitation effect of the multi-level 3D hollow nanosphere and the significant space charge region in type-II heterojunction, the RhB degradation efficiency of MoSe2/CuS reached 96.0% in 120.0minunder Xe (350W) broadband spectrum light irradiation. The photocatalysis mechanism of the hollow MoSe2/CuS core-shell structure was investigated. This work provides an insight into the application of broad spectrum semiconductor heterojunctions to solve environmental problems.

Prediction, identification, and analysis of major B-cell linear epitopes of bomb m 6 from silkworm pupa

Bomb m 6 is one of the most representative allergens in silkworm pupae. The aim of the present study was to investigate the B-cell linear epitopes of Bomb m 6. Sequence propensity– and machine learning–based strategies were first used to predict 12 and 8 candidate epitopes, respectively. Then, 46 overlapping peptides [P1–P46; length, 15 amino acids (AAs); offset, 5 AAs] spanning the Bomb m 6 sequence were synthesized and tested for IgE/IgG reactivity by dot blotting. Seven IgE-binding epitopes and six IgG-binding epitopes were identified. AA61–80, AA136–150, and AA146–150 were identified as the shared dominant IgE/IgG-binding epitopes. The epitopes contain mainly α-helix and β-sheet structures and high proportions of hydrophobic AAs, and are distributed in charged regions. The major peptides of the epitopes were poorly resistant to simulated gastrointestinal fluid digestion. These findings provide a reference for the prevention of and immunotherapy for silkworm pupa allergy.

Incorporating C3N5 and NiCo2S4 to Form a Novel Z-Scheme Heterojunction for Superior Photocatalytic Degradation of Norfloxacin

Due to a combination of increased urbanization, industrialization, and population growth, many pharmaceutical pollutants are currently being discharged into the environment. A possible strategy is critical for eliminating antibiotic pollutants from the environment, and photocatalysis has been generally recognized as an excellent method for successfully degrading antibiotics at a faster pace. In this work, we employed a hydrothermal synthesis approach to create a novel C3N5/NiCo2S4 Z-scheme-based heterojunction with better interfacial charge transfer and used it as a catalyst for the degradation of norfloxacin antibiotic. The optimized 1:1 C3N5/NiCo2S4 (50CN/NCS) shows the highest photocatalytic efficiency of 86.5% in 120 min towards the degradation of norfloxacin (NOR). Such an effective performance can be attributed to the high responsive nature of photocatalyst in the visible region and superior transfer of interfacial charges via Z-scheme transfer in heterojunction. The high charge transfer efficiency and reduced recombination of charge carriers in heterojunction was confirmed by EIS and PL results. The influence of some key factors such as pollutant concentration, catalyst dosage, pH, and coexisting ions on the photocatalytic activity is also investigated in this work. The optimized heterojunction 50CN/NCS also degraded 89.1%, 78.3%, and 93.2% removal of the other pollutants CIP, SDZ, and BPA, respectively.

Diffusiophoresis of ionic catalytic particles

A migration of charged particles relative to a solvent, caused by a gradient of salt concentration and termed a diffusiophoresis, is of much interest being exploited in many fields. Existing theories deal with diffusiophoresis of passive inert particles. In this paper, we extend prior models by focusing on a particle, which is both passive and catalytic, by postulating an uniform ion release over its surface. We derive an expression for a particle velocity depending on a dimensionless ion flux (Damköhler number Da) and show that a charged region is formed at distances of the order of the particle size, provided the diffusion coefficients of anions and cations are unequal. When Da becomes large enough, the contribution of this (outer) region to the particle velocity dominates. In this case, the speed of catalytic passive particles augments linearly with Da and is inversely proportional to the square of electrolyte concentration. As a result, they always migrate toward a high concentration region and, in dilute solutions, become much faster than inert (non-catalytic) ones.

Simulating the anti-aggregative effect of fasudil in early dimerisation process of α-synuclein

The aggregation of the protein α-synuclein into amyloid deposits is associated with multiple neurological disorders, including Parkinson's disease. Soluble amyloid oligomers are reported to exhibit higher toxicity than insoluble amyloid fibrils, with dimers being the smallest toxic oligomer. Small molecule drugs, such as fasudil, have shown potential in targeting α-synuclein aggregation and reducing its toxicity. In this study, we use atomistic molecular dynamics simulations to demonstrate how fasudil affects the earliest stage of aggregation, namely dimerization. Our results show that the presence of fasudil reduces the propensity for intermolecular contact formation between protein chains. Consistent with previous reports, our analysis confirms that fasudil predominantly interacts with the negatively charged C-terminal region of α-synuclein. However, we also observe transient interactions with residues in the charged N-terminal and hydrophobic NAC regions. Our simulations indicate that while fasudil prominently interacts with the C-terminal region, it is the transient interactions with residues in the N-terminal and NAC regions that effectively block the formation of intermolecular contacts between protein chains and prevent early dimerization of this disordered protein.