Changes In Electrical Potential Research Articles

The effect of ions on liquid-solid interface investigated by charge sensitive direct current droplet-based electricity generator

The contact electrification (CE) between DI water and SiO2 or fluorinated polymer has been proven to be mainly due to electron transfer, which is significantly influenced by ions in solution. However, how these ions in water affect the charge transfer at the liquid-solid (L-S) interface is still unresolved, especially for the already charged friction layer. Here, a direct current droplet-based electricity generator (DC-DEG) which is sensitive to the change of charge transfer at the L-S interface is adopted to detect the effects of ions in the neutral salt solution on the charged PTFE surface. The distribution of ions on the charged L-S interface (the change of electric potential on the solid surface) and its effects on the output of DC-DEGs have been studied. The results indicate that the charge transfer of droplets and then the output of DC-DEGs are closely related to the concentrations of salt solutions. Anions can enhance the surface potential of PTFE due to their adsorptions on PFTE while cations can reduce it due to their screen effect. At low ionic concentrations, the surface potential enhancement caused by anion adsorption is larger than that surface potential reduction caused by screen effect from cations. At high ionic concentrations, the electrostatic screen effect of cations increases a lot to weaken the surface potential and reducing the charge separation of droplets induced by electrostatic induction (EI). This work explains the redistribution process of ions at the L-S interface and also provides a clever solution for improving the electrical output performance of DEGs.

A comprehensive study of a long-term creep thermo-mechanical fatigue behavior monitoring of BFRP composite pipeline using electrical capacitance sensors and deep learning algorithm

The composite pipeline is a relatively new and viable alternative pipeline to the more commonly used traditional one due to its good mechanical and fatigue properties and lower production cost. For this purpose, it is critical to assess the mechanical and fatigue performance of composite pipeline material under various working conditions, particularly for monitoring long-term creep thermo-mechanical fatigue behavior. In this paper, a long-term creep thermo-mechanical fatigue behavior in a basalt fiber reinforced polymer laminated composite pipeline is detected through an integrated expert system consisting of the electrical capacitance sensors and a deep learning algorithm. First, a multi-physics finite element model is established for the simulation of a long-term creep thermo-mechanical fatigue behavior in basalt fiber reinforced polymer composite pipelines subjected to long-term fatigue loading of internal pressure and thermal effect. Second, theoretical model results of long-term creep thermo-mechanical fatigue compliance (Sf(t)) over the time of creep are analyzed in pipeline material using the modulus degradation approach. Finally, an electrical potential change between electrical capacitance sensors electrodes corresponding to Sf(t) over the time of creep for some levels of long-term creep thermo-mechanical fatigue (Rf%) is recorded and then used in these datasets for training of the novel deep neural network based on one of the most widely used of the deep neural network families is the convolutional neural network, to predict Sf(t) in pipeline for various Rf% not included in the previous finite element model evaluation (i.e. electrical capacitance sensors technique). In this paper first is detected the long-term creep thermo-mechanical fatigue behavior for Rf%=25%,50%, and 75% from a finite element model and modulus degradation approach, and then is predicted the long-term creep thermo-mechanical fatigue behavior for Rf%=15%,35%,60%, and 85% respectively via deep neural network. The proposed method results are in good agreement with the experimental results available in the literature, thus verifying the accuracy and reliability of the proposed technique and its applicability to other different composite structures.

The Eleutherococcus senticosus fruits' intractum affects changes in the transepithelial electric potential in the distal section of the rabbit's large intestine and inhibits hyaluronidase

Ethnopharmacological relevanceEleutherococcus senticosus (Rupr. et Maxim.) Maxim. has been used in traditional Russian medicine due to its recognized immunostimulant and anti-inflammatory activities. Compounds present in the fruits have demonstrated the capability to modulate the activity of enzymes such as hyaluronidase, suggesting their potential value in the development of effective therapies for various conditions where anti-inflammatory properties are beneficial, such as gastrointestinal diseases and tumor growth. Aim of the studyIn order to support the use of the fruits in folk medicine, this study is aimed to evaluate, post-mortem, the impact of E. senticosus fruits intractum (40 % extract made from fresh fruits) on the transepithelial electrogenic transport of sodium ions in the colon. The objective of this study was also to examine the impact of the intractum on proinflammatory serum hyaluronidase in children diagnosed with acute leukemia. MethodsThe study employed the Ussing technique to examine electrophysiological characteristics of isolated epithelial tissue, using the distal colon wall isolated from 10 New Zealand white male rabbits. The effect of the intractum on the inhibition of human serum hyaluronidase was examined with turbidimetric screening methods, using the blood samples collected from patients diagnosed with acute leukemia. ResultsFor the first time, we discovered that the intractum used in the stimulation fluid, caused hyperpolarization reactions in colon tissue. Statistical analysis showed that these reactions were significantly different in relation to the control. The intractum significantly inhibited hyaluronidase activity with the mean value by group of 60 %, and 40 % for aescin used as a control. ConclusionThe results support the traditional use of the fruits in inflammatory-related diseases. The use of intractum of E. senticosus on the distal colon wall demonstrates its protective effect on the wall integrity and in a relation to hyaluronidase inhibition may additionally indicate its anti-inflammatory property. Thus, the results mean that the intractum may be used in colon-related diseases.

Response of photosynthesis and electrical reactions of wheat plants upon the action of magnetic fields in the Schumann resonance frequency band

ABSTRACT Alternating magnetic fields (MF) with Schumann resonance frequencies accompanied the development of living organisms throughout evolution, but today it remains unclear whether they can have a special biological effect in comparison with surrounding non-resonant frequencies. This work shows some stimulating effect of extremely low-frequency MFs on morphometric parameters and the activity of physiological processes in wheat (Triticum aestivum L.). It is shown that the MF effect is more pronounced for transient processes – photosynthesis reactions and changes in electrical potential caused by turning on light. For light-induced electrical reactions, the dependence of the severity of the effect on the frequency of the applied MF was demonstrated. It is shown that the most pronounced effect occurs in the 14.3 Hz field, which corresponds to the second harmonic of the Schumann resonance. The predominant sensitivity of signal-regulatory systems gives reason to assume the influence of MFs with Schumann resonance frequencies on the interaction of plants with environmental factors under conditions of a changed electromagnetic environment. Such conditions can occur, for example, with an increase in lightning activity caused by climate change, which serves as the basis for the generation of Schumann resonances, and with the development of artificial ecosystems outside the Earth’s atmosphere.

Investigation of guided wave propagation in nanoscale layered periodic piezoelectric plates based on Eringen's nonlocal and strain gradient theory

This paper investigates the dynamic propagation behavior of guided waves in nanoscale media composed of alternating layers of piezoelectric phases. The study employs Eringen's nonlocal and strain gradient theories to derive equations for symmetric wave propagation and the scattering relations of guided waves perpendicular to these structures. Dispersion curves are calculated and plotted to compare these theories, considering the influence of nanoscale size-effect, volume ratio of constituent layers, and material length scale. Using the strain gradient theory, the paper explores the impact of length scale parameters on the propagation behavior of horizontally polarized guided waves in an alternating layer structure of nanoscale piezoelectric material, specifically nanoscale piezoelectric laminates. The analysis involves calculating localization factors and dispersion curves to analyze the effects of size-effect and length scale parameters on wave propagation and band structures. Additionally, the study plots and analyzes changes in mechanical displacement and electrical potential, followed by an investigation and discussion of nanoscale size effects and the effects of the material's length scale parameter on dispersion curves and conversion modes within specific regions. The results highlight that the length scale effect parameter significantly impacts the mode conversion zones and band gap structures, more so than the NLPE continuum theory suggests. As the strain gradient parameter increases, these zones shift towards higher wavenumbers and to the right . Furthermore, introducing the length scale factor results in a substantial decrease in both the formation of conversion zones and the density of dispersion curves.

Albumin Protein Impact on Early-Stage In Vitro Biodegradation of Magnesium Alloy (WE43).

Mg and its alloys are promising biodegradable materials for orthopedic implants and cardiovascular stents. The first interactions of protein molecules with Mg alloy surfaces have a substantial impact on their biocompatibility and biodegradation. We investigate the early-stage electrochemical, chemical, morphological, and electrical surface potential changes of alloy WE43 in either 154 mM NaCl or Hanks' simulated physiological solutions in the absence or presence of bovine serum albumin (BSA) protein. WE43 had the lowest electrochemical current noise (ECN) fluctuations, the highest noise resistance (Zn = 1774 Ω·cm2), and the highest total impedance (|Z| = 332 Ω·cm2) when immersed for 30 min in Hanks' solution. The highest ECN, lowest Zn (1430 Ω·cm2), and |Z| (49 Ω·cm2) were observed in the NaCl solution. In the solutions containing BSA, a unique dual-mode biodegradation was observed. Adding BSA to a NaCl solution increased |Z| from 49 to 97 Ω·cm2 and decreased the ECN signal of the alloy, i.e., the BSA inhibited corrosion. On the other hand, the presence of BSA in Hanks' solution increased the rate of biodegradation by decreasing both Zn and |Z| while increasing ECN. Finally, using scanning Kelvin probe force microscopy (SKPFM), we observed an adsorbed nanolayer of BSA with aggregated and fibrillar morphology only in Hanks' solution, where the electrical surface potential was 52 mV lower than that of the Mg oxide layer.

Dodecanogram (DDG): Advancing EEG technology with a high- frequency brain activity measurement device

EEG measures electric potential changes in the scalp. Even though it has been associated with human thoughts, there has been no direct evidence. The problem with EEG is that it measures variations in current or electric potential in the millisecond time domain, where muscle movement strongly affects the readings. The millisecond time domain is equivalent to the kHz resonance signal generated by any dielectric resonator, and every single cell membrane resonates in this time range. So, the measurement of EEG could come simply from the skin and not from the brain. Therefore, we have advanced EEG technology with the dodecanogram (DDG), which reveals 12 frequency bands or 12 discrete time regions where brain activities are most significant. We measure brain activity using a stream of pulses and a logic analyzer that counts ultra-short pulses needed to emulate brain scalp potential changes. We have created another version of DDG where, using an array of RLC (resistor-inductor-capacitor) resonators, we sense the ultra-low-power electromagnetic radiation from different locations on the brain's surface. Since we measure signals from Hz to THz, covering 12 orders of time ranges as a property of dielectric resonance, unlike EEG, there is a high probability that the DDG signal may truly originate from the brain. We have monitored DDG on an artificial organic brain replica 24/7 for over a year and on multiple human subjects, before and after meditation and concluded that most cognitive, perceptive and emotional bursts occur around 200-700 nanoseconds, not milliseconds, as it was believed for 150 years of EEG era.

Oxidative stress and energy metabolic response of Isochrysis galbana induced by different types of pristine and aging microplastics and their leachates

The aging process and leachate composition of different types of MPs (PS, PS-NH2, PS-COOH and PMMA) with a particle size of 1.0 μm were characterized, and marine microalgae Isochrysis galbana OA3011(I. galbana) was used as test organism to investigate the 96 h toxic effects of MPs before and after aging as well as leachate exposure. Except for polymethyl methacrylate (PMMA), all other tested microplastics showed significant aggregation in seawater, which increased with the presence of surface amino and carboxyl groups, in addition, the increase in polymer dispersibility index (PDI) values after aging reflected more severe aggregation. Fourier transform infrared spectrometer (FTIR) showed that the surface amino groups were shed during the aging of PS-NH2, which can likewise be demonstrated by the change in surface electric potential from positive to negative before and after aging. PMMA, due to the addition of plasticizers (HEHP and DIBP detected in high concentration) and its own structure, has stronger resistance to aging than the other three microplastics, and no significant aging phenomenon occurs. As for I. galbana, growth inhibition, oxidative stress and energy metabolism were tested after exposure to different microplastics and their leachate. It was found that high concentrations of A-PS had a greater negative impact on I. galbana, while the toxic effects of PS-NH2 and PS-COOH on I. galbana behaved in a diametrically opposite way before and after aging compared to PS with the inhibitory effect decreasing after aging, which was caused by the shedding of surface groups. As for PMMA, the differences in the toxic effects on microalgae before and after aging were not significant. The inhibitory effect of low concentrations of PAEs (Phthalate acid esters) in the leachate of PS-COOH on I. galbana was not significant, and the stronger inhibitory effect of 4 d L-PS-NH2 was presumed to be the shedding of positively charged groups.

Generalized piezothermoelasticity of hollow spheres under thermal shock using Lord–Shulman theory

Present investigation deals with the response of a piezoelectric hollow sphere that is subjected to sudden thermal shock. Loading and boundary conditions are assumed to be symmetric so the response of the sphere is also considered to be symmetric. The governing equations of the vessel are obtained which are three in number. These equations include the equation of motion, the energy equation and the Maxwell equation. The energy equation is established in the framework of single relaxation time theory of Lord and Shulman. The established equations are written in terms of temperature change, radial displacement, and electric potential. These equations are provided in a dimensionless presentation for the sake of generality. After that with the aid of the generalized differential quadrature method, the established equations are discreted. Also Newmark time marching scheme is applied to trace the radial displacement, electric potential, and temperature change in time domain. Novel numerical results are then provided to explore the propagation and reflection of electrical, thermal and mechanical waves in a hollow sphere. It is shown that temperature wave propagates with finite speed within the framework of the Lord–Shulman theory.

Determination of cell membrane permeability coefficients: Comparison of models in the case of oocytes

Values of cell membranes permeability coefficients for water and molecules of cryoprotective agents (CPAs) are the necessary characteristics for developing physical-mathematical models describing mass transfer processes through cell membranes in order to predict optimal cell cooling rates. We carried out a comparative analysis of the permeability coefficients of mouse oocyte membranes for molecules of water, ethylene glycol (EG), propane-1,2-diol (1,2-PD) and dimethyl sulfoxide (Me2SO), determined by applying the classical Kedem-Katchalsky model, which considers only the penetration of non-electrolyte molecules (water and CPA) through the membrane, and the model developed by us, which takes into account the transmembrane transfer of ions and the associated changes in the transmembrane electric potential. We shown that calculations based on the developed modified model provide lower values of the permeability coefficients of the oocyte membrane for water and CPA molecules. What is important that the obtained by our modified model permeability coefficients for water molecules do not depend on the type of cryoprotectant, while the application of the classical model both in our studies and works of other authors always gave different values of these coefficients in solutions with different cryoprotectants. Our modified model also makes it possible to determine the dynamics of the transmembrane electric potential of the cell under the conditions of transmembrane mass transfer and the duration of the membrane being influenced by the changes in electric potential, that is a parameter that can directly affect the viability of cells.

Light induced spiking of proteinoids

Proteinoids, or thermal proteins, are produced by heating amino acids to their melting point and initiating polymerisation to produce polymeric chains. In aqueous solutions proteinoids swell into hollow microspheres. These microspheres produce endogenous burst of electrical potential spikes and change patterns of their electrical activity in response to illumination. We report results on a detailed investigation on the effects of white cold light on the spiking of proteinoids. We study how different types and intensities of light determine proteinoids’ spiking amplitude, period, and pattern. The results of this study will be utilised to evaluate proteinoids for their potential as optical sensors and their application in unconventional computing.

Free vibration and nonlinear dynamic response of sandwich plates with auxetic honeycomb core and piezoelectric face sheets

This article analyses the nonlinear dynamic behavior and the free vibration of a piezoelectric auxetic honeycomb sandwich plate resting on a Pasternak elastic substrate. The plate includes two face sheets of piezoelectric material and an auxetic honeycomb core with a negative Poisson ratio. The first-order shear deformation plate theory, together with the von Kármán type nonlinear strain-displacement relationship, is used to establish the nonlinear equations of motion. Linear electric potential change with piezoelectric layer thickness is assumed. Two types of boundary conditions, namely immovable and movable simply supported, are considered. The displacement-time and acceleration-displacement curves under dynamic loads are determined by using the Galerkin and Runge-Kutta fourth-order methods. Verification examples have been performed and confirmed the accuracy of the model. Finally, several novel investigations have been conducted to evaluate the effect of material, geometrical parameters, and elastic substrate coefficients on the frequency and nonlinear dynamic characteristics of piezoelectric auxetic honeycomb sandwich plates for both open-circuit and closed-circuit operation.

Modelling and Optimization of the Differential Surface Capacitance in Electrolyte-Gated Graphene Field-Effect Transistors

Graphene field-effect transistors (GFETs) are a promising avenue for the detection of biomarkers, allowing to envision improvements in diagnostic approaches for different types of cancer and other diseases. To enable such applications, the detection metrics of the devices must be optimized, including their sensitivity, selectivity, and stability. In particular, the capacitance of the device is one of the key determinants of the sensitivity of the electrical current of graphene to nearby changes in electrical potentials. In this presentation, we present our approach to optimize the surface capacitance of electrolyte-gated GFETs, by investigating theoretically and/or experimentally the effect of specific design parameters, including the graphene area, the removal of the backgate, and the passivation of electrodes. On the theoretical side, a mathematical representation of the device capacitance was established as an equivalent circuit of capacitors modelling for the quantum capacitance of graphene, the backgate capacitance, and the capacitance of electrical double layers in the electrolyte. On the experimental side, microchips of GFET arrays were assembled using microfabrication techniques on two types of substrates: a standard Si++/SiO2 wafer in which the doped silicon layer is used as a backgate, and a pure non-conducting borosilicate glass wafer in comparison. The capacitance of the devices was then measured using a custom parallel electrical prober by stepping the applied voltage in the solution and analyzing the resulting current response through a standard RC direct current model. We will present our analyses by comparing the relative impact of electrode passivation, backgate usage, and graphene area on the capacitance of devices. These results will enable a rational design of GFET devices with improved sensitivity for their use in applications such as biological, chemical, and gas sensing.

Time-Dependent Features of Mass Transfer and Transmembrane Potential in Erythrocytes During Equilibration in Cryoprotective Solutions

On the basis of the developed physical and mathematical model of mass transfer, which takes into account the transmembrane transfer of non-electrolytes, basic ions and the associated changes in the transmembrane potential, the redistribution of osmotically active substances during equilibration of erythrocytes in cryoprotective solutions was investigated. Time parameters of changes in concentrations of osmotically active substances inside and outside cells, as well as transmembrane electric potential, were calculated. It is shown that during the exposure of human erythrocytes to 1M solutions of glycerol, 1,2-propanediol (1,2-PD) and dimethylsulfoxide (DMSO), the sign of their transmembrane electric potential changes three times, and in solutions of ethylene glycol (EG) and of acetamide (AA) – once. The analysis of the obtained results showed that the most acceptable for further cryopreservation from the point of view of erythrocytes reaching a state close to equilibrium in a 1M solution of glycerol was their equilibration for 5.5 min, and in solutions of DMSO, AA, EG and 1,2-PD with the same concentration – 1 min. At the same time, the cells remain somewhat dehydrated (by 5.5–7.5%), and the concentrations of cryoprotectants inside erythrocytes change insignificantly during longer exposure. The indicated degree of dehydration does not affect cell viability, but reduces the likelihood of intracellular ice formation during subsequent freezing.

Diurnal Variations in Vegetation Activity affecting Shallow Groundwater Flow identified by Microthermal Measurements

Observations of summer microthermal temperature variations suggest, next to hydrological factors, a significant influence of plant activity on groundwater flow in fractured claystone materials. Variations in groundwater microtemperature were compared to variations in meteorological parameters and electrical potential of plants. With an increase in surface temperature, relative air humidity decreases and an increase in tree electrical potential, measured as the difference between the northern and the southern stem exposure (N–S), can be observed. This increase in electrical potential is concomitant with a change in groundwater temperature of approximately 2 mK. This relationship does not always occur. At high temperatures (+30°C) the decrease amounts to just 1 mK. This fact is related to the change in transpiration of plants, decreased or even suspended at high surface temperatures. A frequency analysis of all data showed a daily frequency of high magnitude in all parameters. Possibly changes in the macro weather situation events were observed in the results of atmospheric pressure, southern electric potential and groundwater temperature. The lag time between changes in electric potential and subsurface microtemperature changes amounts to 17 hours, possibly a result of the electrical potential difference between the northern and the southern exposure of the stem (N–S), and 5 hours, the result of the change in electrical potential difference between the southern and the northern stem exposure side (S–N). A comparison between potential changes and the computed change in gravity resulting from earth tidal effects showed that the correlation between the subsurface temperature variation with up to 2 mK and the change in surface temperature variation does not match directly. Other study shows that the impact of earth tides on subsurface microtemperature variation amounts to ca. 1mK. The effect of groundwater abstraction by mature vegetation is determined at the same range. Atmospheric tides can be correlated with the changes in north and south electric potentials.

Mouse Cardiac Arrest Model for Brain Imaging and Brain Physiology Monitoring During Ischemia and Resuscitation.

Most cardiac arrest (CA) survivors experience varying degrees of neurologic deficits. To understand the mechanisms that underpin CA-induced brain injury and, subsequently, develop effective treatments, experimental CA research is essential. To this end, a few mouse CA models have been established. In most of these models, the mice are placed in the supine position in order to perform chest compression for cardiopulmonary resuscitation (CPR). However, this resuscitation procedure makes the real-time imaging/monitoring of brain physiology during CA and resuscitation challenging. To obtain such critical knowledge, the present protocol presents a mouse asphyxia CA model that does not require the chest compression CPR step. This model allows for the study of dynamic changes in blood flow, vascular structure, electrical potentials, and brain tissue oxygen from the pre-CA baseline to early post-CA reperfusion. Importantly, this model applies to aged mice. Thus, this mouse CA model is expected to be a critical tool for deciphering the impact of CA on brain physiology.

Spatial electric potential distributions and damage mapping in 3D carbon fiber/epoxy angle-interlock woven composites with different current directions

Exploring electric potential distributions in carbon fiber reinforced polymer composites (CFRPs) is important in electrical-based structural health monitoring for in situ damage detection. Here we investigate influences of current injection angles, electrode locations, and current injection pairs on the electric potential distributions in 3D carbon fiber/epoxy angle-interlock woven (AIW) composites. We have conducted different types of electric potential measurements and established a linear anisotropic conductivity model to reveal the electric potential distributions. It was found that the curved warp yarns form many contacts and increase the conduction path, leading to lower electric conductivity and flatter potential field than those of the weft yarn with straight alignment. The orientation and value of surface electric potential field change depend on current flow direction caused by current injection mode (CIM) and conduction mechanism due to yarn arrangement. Oblique current directed at an angle of 45° is more sensitive in indicating interior damage than that of current parallel to the yarn direction. It is recommended that the oblique current injection should be used to provide effective damage sensing for CFRPs with complex structures.

Both network architecture and micro cracks effects on lacuno-canalicular liquid flow efficiency within the context of multiphysics approach for bone remodeling

When physical forces are applied to bone, its mechanical adaptive behaviors change according to the microarchitecture configuration. This leads to changes in biological and physical thresholds in the remodeling cell population, involving sensor cells (osteocytes) interacting with each other and changes in osteocyte shape due to variation in lacunar shape. The resulting alterations in fluid flow leads to changes in the membrane electrical potential and shear stress. Eventual creation of microcracks, may lead in turn to modify cell activity. In contrast, the redundancy in the lacuno canalicular network (LCN) interconnectivity maintains partial flow. Our goal was to investigate the role of fluid flow in LCN by proposing a model of electro-mechanical energy spread through inhomogeneous microarchitectures. We focused on mechano-sensitivity to changes in load-induced flow impacted by neighboring micro cracks and quantifying its critical role in changing, velocity, shear stress and orientation of liquid mass transportation from one cell to another. To enhance the concept of intricacy LCN micro-structure to fluid flow, we provide a new combined effects factor considered as osteocytes sensor efficiency. We customized an influence function for each osteocyte, coupling: in one hand, the spatial distribution within remodeling influence areas, conducting a significant fluid spread, leading hydro-dynamic behavior and impacted further by presence of micro cracks and; in other hand, the fluid electro kinetic behavior.As an attempt to fill the limitations stated by many of the recent studies, we reveal in numerical simulation, some results which cannot be measured in vitro/in vivo studies. Numerical calculations were performed in order to evaluate, among many others, how liquid flow conditions changes between lacunas, how the orientation and the magnitude of the governing flow in LCN can regulate osteocytes efficiency. In addition to be regulated by osteocytes, a direct effects of fluid flow are also acting on osteoblast activity. In summary, this new approach considers mechano-sensitivity in relation to liquid flow dynamic and suggests additional pathway for Osseo integration via osteoblast regulation. However, this novel modeling approach may help improve the mapping and design bone scaffolds and/or selection of scaffold implantation regions.

Understanding the evolution of lithium dendrites at Li6.25Al0.25La3Zr2O12 grain boundaries via operando microscopy techniques

The growth of lithium dendrites in inorganic solid electrolytes is an essential drawback that hinders the development of reliable all-solid-state lithium metal batteries. Generally, ex situ post mortem measurements of battery components show the presence of lithium dendrites at the grain boundaries of the solid electrolyte. However, the role of grain boundaries in the nucleation and dendritic growth of metallic lithium is not yet fully understood. Here, to shed light on these crucial aspects, we report the use of operando Kelvin probe force microscopy measurements to map locally time-dependent electric potential changes in the Li6.25Al0.25La3Zr2O12 garnet-type solid electrolyte. We find that the Galvani potential drops at grain boundaries near the lithium metal electrode during plating as a response to the preferential accumulation of electrons. Time-resolved electrostatic force microscopy measurements and quantitative analyses of lithium metal formed at the grain boundaries under electron beam irradiation support this finding. Based on these results, we propose a mechanistic model to explain the preferential growth of lithium dendrites at grain boundaries and their penetration in inorganic solid electrolytes.

The effects of acupuncture on clinical efficacy and steady-state visual evoked potentials in insomnia patients with emotional disorders: A randomized single-blind sham-controlled trial.

The aim of this study was to observe the clinical effects and brain electrical potential changes following acupuncture in the treatment of insomnia patients with mood disorders. Ninety patients with insomnia who met the inclusion criteria were randomly divided into the active acupuncture group (AA group, n = 44) and sham acupuncture group (SA group, n = 46) at a ratio of 1:1. The primary outcome was the total score of the Pittsburgh Sleep Quality Index (PSQI), and the secondary outcomes were the total effective rate, Self-Rating Anxiety Scale (SAS), Self-Rating Depression Scale (SDS) scores, and values of steady-state visual evoked potentials (SSVEP). The two groups received acupuncture or sham acupuncture 10 times (2 weeks). Finally, the total PSQI scores of the AA group and SA group were significantly different (p < 0.05) at 2 weeks (6.11 ± 2.33 vs. 10.37 ± 4.73), 6 weeks (6.27 ± 1.39 vs. 11.93 ± 3.07), 18 weeks (6.32 ± 2.84 vs. 11.78 ± 2.95) and 42 weeks (8.05 ± 3.14 vs. 12.54 ± 2.81). Further analysis found that AA group patients received acupuncture treatment at any age after the same effect (p > 0.05). The SAS and SDS scores of the AA group were also significantly different from those of the SA group at each assessment time point (p < 0.05). The total effective rate of the AA group was 81.82%, while that of the SA group was 30.43% (p < 0.05). There was no significant difference between the AA group and SA group only in the brain potential of the parietal lobe (F4), left temporal lobe (C3) and right temporal lobe (T8) (P > 0.05), but there was a significant difference between other brain regions (P < 0.05). In addition, correlation analysis showed that there was a certain positive correlation between the total PSQI score, SAS score, efficacy level, and SSVEP value in the AA group as follows: C4 and the total PSQI score (r = 0.595, P = 0.041), F3 and SAS score (r = 0.604, P = 0.037), FPz and efficiency level of the frontal lobe (r = 0.581, P = 0.048), and O2 and efficiency level of the occipital lobe (r = 0.704, P = 0.011). Therefore, acupuncture have a good clinical effect on patients with insomnia and emotional disorders and have a significant regulatory effect on abnormally excited brain potentials.