Ionic Polarization Research Articles

Impact of Graphene Nanofluid on Ionic Polarization in Reservoir Sandstone under Electric Double Layer

The improved oil recovery (IOR) is a way of enhancing the reservoir properties with the use of nanomaterials to detach the oil molecule from the trapped zone. The polarization effect on reservoir sandstone under an electric double layer is one of the major research interests. The nanoparticles agglomeration such as graphene nanofluid due to poor dispersion in reservoir zone can be a major challenge that can lead to low reservoir permeability are well elucidated. This study investigated the influence of graphene nanofluid on the ionic polarization under an electric double layer in reservoir sandstone. Saturated Berea sandstone was used to investigate the interaction of ionic species on reservoir sandstone with the aid of Field-emission microscopy (FESEM), Energy dispersive X-ray mapping (EDX), Fourier Transform Infrared Spectroscopy (FTIR), Raman spectral analysis, and Core flooding experiment. This research gives information on the adsorption of ions within an electric double layer and its polarization mechanisms. It was revealed from the experimental result that ionic polarization occurs at 9.97 GHz with a 5.8nm wavelength shift which improves the mobility of the reservoir and in turn increases oil recovery factors. Graphene nanoparticles show a positive effect on both reservoir oil viscosity and stabilization characteristics of drilling fluids, wettability alteration, interfacial tension, and improving the emulsion Keywords: Nanomaterials, Sandstone, Electric double layer, Graphene

Relationship between microwave dielectric properties and structure of Ca2+-substituted ZnZrTa2O8 ceramics

Herein, Zn1-xCaxZrTa2O8 (0 ≤ x ≤ 0.1) ceramics with wolframite structure were prepared via the solid-state reaction method. Zn0.94Ca0.06ZrTa2O8 exhibited the best dielectric properties with εr = 23.14, Q × f = 140,915 GHz (@7.79 GHz), and τf = −26.42 ppm/°C. εr increases gradually with the Ca2+ content. The change in εr is related to the Ca2+ ion polarizability and the redshift of Raman vibrational modes. Appropriate Ca2+ substitution makes the dominant Ta-O have higher lattice energy, resulting in a lower dielectric loss. In addition, the reduction of FWHM of Raman characteristic peaks also had a positive effect on reducing the dielectric loss. First-principles calculations illustrate that the trace substitution of Ca2+ leads to an increase in the electron cloud density of the [Zn/Ca/ZrO6] octahedra, resulting in lower dielectric losses. Suitable Ca2+ substitution resulted in higher bond energy and smaller [Zn/Ca/ZrO6] octahedral distortion, implying that τf is closer to 0 ppm/°C.

Spin Effect to Promote Reaction Kinetics and Overall Performance of Lithium-Sulfur Batteries under External Magnetic Field.

Lithium-sulfur batteries (LSBs) are still limited by the shuttle of lithium polysulfides (LiPS) and the slow Li-S reaction. Herein, we demonstrate that when using cobalt sulfide as a catalytic additive, an external magnetic field generated by a permanent magnet can significantly improve the LiPS adsorption ability and the Li-S reaction kinetics. More specifically, the results show both experimentally and theoretically how an electron spin polarization of Co ions reduces electron repulsion and enhances the degree of orbital hybridization, thus resulting in LSBs with unprecedented performance and stability. Under an external magnetic field, LSBs with 0.0084 % per cycle decay rate at 2 C during 8150 cycles are produced. Overall, this work not only demonstrates an effective strategy to promote LiPS adsorption and electrochemical conversion in LSBs at no additional energy cost but also enriches the application of the spin effect in the electrocatalysis fields.

Spin Effect to Promote Reaction Kinetics and Overall Performance of Lithium‐Sulfur Batteries under External Magnetic Field

AbstractLithium‐sulfur batteries (LSBs) are still limited by the shuttle of lithium polysulfides (LiPS) and the slow Li−S reaction. Herein, we demonstrate that when using cobalt sulfide as a catalytic additive, an external magnetic field generated by a permanent magnet can significantly improve the LiPS adsorption ability and the Li−S reaction kinetics. More specifically, the results show both experimentally and theoretically how an electron spin polarization of Co ions reduces electron repulsion and enhances the degree of orbital hybridization, thus resulting in LSBs with unprecedented performance and stability. Under an external magnetic field, LSBs with 0.0084 % per cycle decay rate at 2 C during 8150 cycles are produced. Overall, this work not only demonstrates an effective strategy to promote LiPS adsorption and electrochemical conversion in LSBs at no additional energy cost but also enriches the application of the spin effect in the electrocatalysis fields.

A Parametric Study of Oxygen Ion Cyclotron Harmonic Wave Excitation and Polarization by an Oxygen Ring Distribution

AbstractOxygen ion cyclotron harmonic (OCH) waves are electromagnetic emissions with frequencies near the harmonics of the oxygen ion cyclotron frequency. These waves can be excited by an energetic O+ ring distribution. Here, we perform a parametric study of OCH waves by an O+ ring distribution. We investigate the effects of ring concentration (ηho), velocity (vr), temperature (Tr), total O+ concentration (ηo), and wave normal angles (WNAs) on the wave growth rate and polarization. We find that four‐wave modes are related to OCH waves. The growth rates and frequency range increase with ηho and ηo and decrease with Tr. The peak growth rate roughly follows the first peak of (square of the Bessel function corresponding to the O+ ring) or cold plasma wave modes, which can be used to explain the vr and WNA dependences. OCH waves shift from the transverse mode to the compressional mode as vr increases.

Ultraductile Cementitious Structural Health Monitoring Coating: Waterborne Polymer Biomimetic Muscle and Polyhedral Oligomeric Silsesquioxane‐Assisted C‐S‐H Dispersion

AbstractCement‐based sensors (CBSs) have demonstrated potential in structural health monitoring (SHM) despite rare applications due to their poor flexibility and sensing accuracy/protection with robustness. Herein, a promising strategy is reported to design a waterborne epoxy resin (WEP)‐modified cement‐based composite coating sensorcapable of simultaneous stable SHM and durable protection. The interpenetrating network (IPN) formed by WEP within cement paste is bionic to the toughness and crack resistance of biological muscle tissue and balances the ion permeation performance and polarization of hydration products. The polymerization‐redispersion progress and mechanism of calcium silicate hydrate (C‐S‐H) gel modified with [3‐(2‐aminoethylamino)‐propyl]trimethoxysilane silsesquioxane (C‐POSS) are characterized and revealed. The results show that the muscle‐like IPN increases the cement‐based coatings’ maximum deflection angle to 30° and improves the monitoring accuracy of compressive, tensile, and fatigue microchanges of concrete structures to more than 95%. The POSS···Ca2+···C‐S‐H interaction in C‐POSS partially transferred the intra‐adhesive hydrogen bonds surrounding the nanoconducer into electrostatic bridging ones to maintain an excellent electromechanical conductive dispersion.

Effect of B2O3 and Li2O on vibrational, thermal and optical properties of 50Bi2O3-15PbO-(35-x)B2O3-xLi2O (0 ≤ x ≤ 25 mol%) glasses

Bi2O3 based glasses have been proven as promising optical materials with regard to their 6 s2 lone pair electrons. By melt quenching, the highly thermal stable glasses 50Bi2O3-15PbO-(35-x)B2O3-xLi2O (where 0 ≤ x ≤ 25 mol%) were prepared. The short range order of the glasses was verified with XRD and DSC measurements. DSC analysis showed that thermal parameters varied non-linearly with increase of Li2O. Density (ρ), molar volume (Vm), oxygen packing density (OPD) and oxygen molar volume (Vo) were calculated and their compositional dependency was discussed in detail. Energy dispersive X-Ray (EDX) spectrometry analysis validated the stoichiometry of sample composition. FTIR analysis illustrated that the glass network comprise of BiO3, BiO6, BO3 and BO4 structural units together with non-bridging oxygens. The computed optical properties like optical band gap (Eopt), refractive index (n), Urbach energy (∆E), molar refraction (RM), metallization criterion (M) and oxide ion polarizability (αO2-) were observed to be non-linearly varied with the addition of Li2O. The interplay between the structural roles of Li2O and Bi2O3 was instrumental for the observed variations in all the properties. BiPBL4 glass showed the highest thermal stability (175 °C) and the high kgl value among the glass series. The incorporation of Li2O in presence of low mol% of B2O3 with Bi2O3-PbO endowed these glasses to have the low phonon energy. The analysis carried out in this work showed that these glasses might useful for optoelectronic devices and optical fiber drawing applications.

Band gap engineering and microwave dielectric properties evolution of mixed (Sr, La, Ce) TiMgO3 titanate–aluminate system

A mixed perovskite titanate-aluminate [(1-x)(Sr0.6La0.2Ce0.2Ti0.8Mg0.2O3)-xNdAlO3 for x = 0.1 to 0.4] solid solution was successfully synthesized. X-ray diffraction patterns (XRD) and Rietveld refinement results indicated a stable perovskite phase with a cubic structure, in which Nd3+ occupies the A-site randomly while Al3+ occupies the B-site. No additional reflection spots (superlattice reflections) were detected in the HRTEM pattern (see SAED), confirming the cubic symmetry. All samples showed small Urbach tails, mainly due to compositional disorder. Microstructural analysis based on atomic force microscopy (AFM) showed no traces of impurity phases. For x = 0.4, excellent microwave dielectric properties (MWD) are obtained with a quality factor (Q × f) of 37,131 GHz at f = 5.2801 GHz, relative permittivity (εr) of 43, and temperature coefficient of resonant frequency (τf) of +1.3 ppm/°C. Variations in εr, Q × f values, and τf may be related to changes in relative density (ρrel), ion polarizability, optical band gap, and tolerance factor, respectively.

The effects of polarization on the rotational diffusion of ions in organic ionic plastic crystals.

Organic ionic plastic crystals (OIPCs), which consist of organic molecular ions, are considered excellent candidates for solid electrolytes due to their high ionic conductivity in solid phases. Molecular ions undergo either rotational or conformational relaxation at certain temperatures in OIPCs. There have been molecular simulations to understand the rotational motion. The polarizability of ions was, however, often ignored in simulations due to the high computational cost. Since the polarizability may affect the translational diffusion, the ionic conductivity, and the phase transition of ionic liquids, it should be of interest to investigate how the polarizability would affect the rotational diffusion of ions in solid phases. In this work, we perform extensive atomistic molecular dynamics simulations for two different kinds of OIPCs, 1-methyl-3-methylimidazolium hexafluorophosphate ([MMIM][PF6]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]). We employ various simulation models for ions by turning on and off the polarization in their interaction potentials. We find that the polarizability hardly affects the density, the crystalline structure, and the phase transition of both OIPCs. However, a certain rotational motion, especially the rotational diffusion of PF6 - in [MMIM][PF6] OIPCs, is enhanced by a factor of up to four when the polarizability is turned on. The PF6 - in [MMIM][PF6] OIPCs undergoes rotational hopping motions more significantly due to polarizability. We find that the rotational diffusion of a certain ion can be enhanced only when the polarization results in a significant change in the dipole moment of the neighboring ions around the ion.

Carbon-Binder Optimization for Lithium-Ion Battery Extreme Fast Charge

Battery performance is strongly correlated with electrode microstructure and weight loading of the electrode components. Among them are the carbon-black and binder additives that enhance effective conductivity and provide mechanical integrity. However, these both reduce effective ionic transport in the electrolyte phase and reduce energy density. Therefore, an optimal additive loading is required to maximize performance, especially for fast charging where ionic transport is essential. Such optimization analysis is however challenging due to the nanoscale imaging limitations that prevent characterizing this additive phase and thus quantifying its impact on performance.In this work [1], an additive-phase generation algorithm [2] has been developed to remedy this limitation and identify percolation threshold used to define a minimal additive loading (cf. figure, left). Impact of carbon-black binder (CBD) loading on electrochemical performance has been investigated through a wide array of numerical methods and experiments on NMC/graphite cells. These range from the representation, characterization, and homogenization of electrode microstructures, battery macroscale modeling, and impedance and rate capabilities measurements on various cell formats. The combined work provides information on connectivity/percolation of the solid network, effective solid conductivity and ionic diffusivity, interfacial area, cell capacity, lithium plating, impedance, and transport polarization at the beginning of life (BOL) [1]. Rate capability test demonstrates capacity improvement at fast charge at BOL (cf. figure, right), from 37% to 55%, respectively for high (10%wt) and low (4%wt) additive loading during 6C CC charging (and from 80% to 86% at the end of 10 min 6 CC-CV), in agreement with macroscale model. Improvements are attributed to a combination of lower cathode impedance, reduced electrode tortuosity and cathode thickness [1].[1] F. Usseglio-Viretta et. al., Carbon-binder Weight Loading Optimization for Improved Lithium-ion Battery Rate Capability, submitted to Journal of the Electrochemical Society [2] F. Usseglio-Viretta et. al., SoftwareX, 17, 100915 (2022), https://doi.org/10.1016/j.softx.2021.100915 Figure 1

Continuous Ion Separations Using Non-Faradaic Capacitive AC Ratcheting

Traditional electrochemical separations processes require Faradaic reactions for sustained currents. We discovered that this limitation can be overcome by oscillating the applied potential across an ion-permeable material that has an asymmetric electric potential profile. We demonstrated this phenomenon for the first time using a flashing ratchet consisting of a nanoporous anodized aluminum oxide membrane infiltrated with salt water and containing metallic contacts on either side. When a symmetric +/-300 mV square-wave potential was applied to the metallic contacts at a frequency of ~100 Hz, an open-circuit potential as large as ~50 mV was observed between Ag/AgCl electrodes immersed in the chloride-containing electrolyte and positioned across the membrane. While this open-circuit potential was determined to be a consequence of net ionic polarization, additional electrochemical data were also consistent with transport of neutral salt across the membrane via a proposed ambipolar transport mechanism. In comparison, application of a DC potential bias resulted in non-Faradaic charging, and a near-zero long-time open-circuit potential. Moreover, high ionic strengths and large pore sizes diminished ratcheting behavior, consistent will more complete screening of surface charges in the nanopores. Collectively, this work represents a new paradigm for direct ion pumping and salt separations that requires no Faradaic reactions or additional transport pathway for ions or electrons.

Empirical electronic polarizabilities for use in refractive index measurements at 589.3 nm: Hydroxyl polarizabilities

Abstract Refractive indices of minerals and inorganic compounds can be calculated from their chemical compositions using the additivity rule for electronic polarizabilities and converting the sum of polariz-abilities α using the Anderson-Eggleton relationship:αAE=(nD2-1)Vm4π+(4π3-2.26)(nD2-1) with the molar volume Vm solved for the mean refractive index nD at 589.3 nm. Whereas the polariz-ability of cations is a single parameter, the polarizability of anions is described by a two-parameter term α−=α−o10−No/Van1.20 with α– = anion polarizability, Van = anion molar volume, and the two least-squares parameters α−o (corresponding to free-ion polarizability) and No. For hydroxyls, Shannon and Fischer (2016) introduced different parameter sets for non-H-bonded hydroxyls (α−o = 1.79 Å3, No = 1.792 Å3.6) and moderately strong H-bonded hydroxyls (α−o = 1.73 Å3, No = 2.042 Å3.6). In an effort to understand the lower polarizability of the H-bonded hydroxyl ions, we have evaluated observed and calculated polarizabilities, O-H, H∙∙∙O, O∙∙∙O distances, and O-H∙∙∙O angles in 10 minerals with non-hydrogen-bonded hydroxyls (mean <O∙∙∙O> distance 3.143 Å, mean <H∙∙∙O> distance 2.352 Å), in seven minerals with H-bonded-hydroxyls (<O∙∙∙O> = 2.739 Å, <H∙∙∙O> = 1.856 Å), and in 10 minerals with very strongly H-bonded hydroxyls (<O∙∙∙O> = 2.531 Å, <H∙∙∙O> = 1.525 Å). On the basis of quantum chemical cluster calculations using atomic parameters of well determined crystal structures of hydroxyl containing compounds, we found that calculated intrinsic polariz-abilities of OH are correlated with the hydrogen bond lengths H∙∙∙O and O∙∙∙O between donor and acceptor of the H-bond. This is demonstrated for LiOH, brucite [Mg(OH)2], portlandite [Ca(OH)2], clinometaborite (β-HBO2), sassolite (H3BO3), archerite (KH2PO4), kalicinite (KHCO3), metaborite (γ-HBO2), and NaPO2(OH)2. Thus, we find that these summed intrinsic polarizabilities for OH-bonds which are involved in H-bonding are significantly lower than the corresponding summed intrinsic polarizabilities for OH-bonds not involved in H-bonding. We attribute the reduction in polarizability of hydroxyl ions in clinometaborite, sassolite, archerite, kalicinite and metaborite, and the compound NaPO2(OH)2 to the presence of H-bonds and a reduction of Hirshfeld atomic charge on the O atom.

Effect of A-site modification on structural and microwave dielectric properties of calcium titanate

This article presents studies on characteristics properties of CaTiO3, Ca0.8Sr0.2TiO3, and Ca0.6La0.8/3TiO3 ceramics. These ceramics were synthesized using the solid-state reaction process. Structural examination revealed that the grown ceramics have an orthorhombic structure with the Pbnm space group. The random distribution of particle size was shown through morphological investigation. Apparent density of developed ceramics was determined using the Archimedes technique and found to be ˂ 90%. The microwave dielectric properties of grown ceramics are compared on the basis of ionic polarizability. It is observed that partial replacement of Ca-ions by Sr-ions provides a high permittivity value (er = 168.93), higher quality factor Q × f = 9,330 GHz), and enhanced positive temperature coefficient of resonant frequency (tf = 908.17). However, the substitution of Ca-ions by La-ions offers a low permittivity value (113.35), higher quality factor (16,730 GHz), and decreased temperature coefficient of resonant frequency (229.49 ppm/°C). These materials can be used with the ceramics possessing a negative temperature coefficient of resonant frequency to balance its tf- value nearly to zero.

Ion Drift and Polarization in Thin SiO2 and HfO2 Layers Inserted in Silicon on Sapphire.

To reduce the built-in positive charge value at the silicon-on-sapphire (SOS) phase border obtained by bonding and a hydrogen transfer, thermal silicon oxide (SiO2) layers with a thickness of 50–310 nm and HfO2 layers with a thickness of 20 nm were inserted between silicon and sapphire by plasma-enhanced atomic layer deposition (PEALD). After high-temperature annealing at 1100 °C, these layers led to a hysteresis in the drain current–gate voltage curves and a field-induced switching of threshold voltage in the SOS pseudo-MOSFET. For the inserted SiO2 with a thickness of 310 nm, the transfer transistor characteristics measured in the temperature ranging from 25 to 300 °C demonstrated a triple increase in the hysteresis window with the increasing temperature. It was associated with the ion drift and the formation of electric dipoles at the silicon dioxide boundaries. A much slower increase in the window with temperature for the inserted HfO2 layer was explained by the dominant ferroelectric polarization switching in the inserted HfO2 layer. Thus, the experiments allowed for a separation of the effects of mobile ions and ferroelectric polarization on the observed transfer characteristics of hysteresis in structures of Si/HfO2/sapphire and Si/SiO2/sapphire.

Medium K and temperature-stable Co2+-substituted LiNb0.6Ti0.5O3 microwave dielectric ceramics for LTCC miniaturized applications

At present, 5 G communication is developing rapidly, devices are becoming miniaturized, which requires the continuous emergence of materials with high dielectric constant. In this work, choosing Co2+ to substitute Li1–2xCoxNb0.6Ti0.5O3 (LCNT, 0 ≤ x ≤ 0.1) + 0.4 wt% LBSCA ceramics successfully achieved high permittivity εr and temperature stable resonant temperature frequency coefficient τf sintered at 950 ℃, including εr∼62, Q×f∼6255 GHz, and τf∼0.97 ppm/℃ (x = 0.02), εr∼56.55, Q×f∼7090 GHz, and τf∼− 28.07 ppm/℃ (x = 0.06). Meanwhile, the influence of Co2+ on LNT ceramics for phase composition, micro-structure, microwave dielectric performance and Raman vibration had been studied in detail. All samples belonged to M phase. Rod-like or blocky grains were gradually refined, indicating that Co2+ had the effect of grain refinement. In microwave dielectric performance, ionic polarizability played a leading role in εr, Q×f value was positively correlated with the bulk density, τf directly depended on the average repeatable layer N. In Raman spectroscopy, three modes of Raman vibration had been identified as translation or rotation of Li+ ions, Nb/Ti bond vibration, [Nb/TiO6] octahedral vibration. To meet low temperature co-fired applications, the LCNT (x = 0.02) ceramic didn’t react with Ag, which suggested it was achieving candidates for the next generation of medium K LTCC materials.

Cu2+-Ion-Substitution-Driven Microstructure and Microwave Dielectric Properties of Mg1-xCuxAl2O4 Ceramics.

In this work, Cu-substituted MgAl2O4 ceramics were prepared via solid-state reaction. The crystal structure, cation distribution, and microwave dielectric properties of Mg1−xCuxAl2O4 ceramics were investigated. Cu2+ entered the MgAl2O4 lattice and formed a spinel structure. The substitution of Cu2+ ions for Mg2+ ions contributed to Al3+ ions preferential occupation of the octahedron and changed the degree of inversion. The quality factor (Qf) value, which is correlated with the degree of inversion, increased to a maximum value at x = 0.04 and then decreased. Ionic polarizability and relative density affected the dielectric constant (εr) value. The temperature coefficient of the resonant frequency (τf) value, which was dominated by the total bond energy, generally shifted to the positive direction. Satisfactory microwave dielectric properties were achieved in x = 0.04 and sintered at 1550 °C: εr = 8.28, Qf = 72,800 GHz, and τf = −59 ppm/°C. The Mg1−xCuxAl2O4 solid solution, possessing good performance, has potential for application in the field of modern telecommunication technology.

On closed-shell interactions between heavy main-group elements.

A series of di- and polymetal complexes involving closed-shell, heavy main-group atoms and ions shows a selection of special physical properties. These involve short metal-metal contacts, low entropies of formation and, most interestingly, strong Raman bands at low wavenumbers. These results together with the constitution of the coordination compounds, where the majority of electrons are assembled on the highly polarizable metal atoms and ions, experimental results have been interpreted in terms of direct, partial covalent metal-metal bonding. Previous theoretical studies have challenged this view and instead attributed the obvious attractive forces involved to secondary-type of interactions, such as dispersion. This study utilizes a multitude of theoretical tools, such as natural bond order (NBO) and natural energy decomposition analysis (NEDA), non-covalent interaction (NCI) analysis, electron localization functions (ELFs), and atoms-in-molecules (AIM) to characterize the interactions in models comprising closed-shell dimers, as well as experimentally studied ring and cage systems constituting the main reason for the hypotheses on metal-metal interactions. The results show that all experimental results can be attributed to the covalent interactions between the electron-rich, metal centers and the bridging anions in ring and cage coordination compounds of high symmetry, where the experimentally observed effects can be traced to the combination of covalent interactions between the metal centers and the anions along the edges of the ring and cage systems in combination with the cooperative effects generated by the high symmetry of these ring and cage systems.

Effect of Er3+ ions on the structural, optical and Judd-Ofelt (JO) intensity parameters of (Bi2O3-BaTiO3) glass system and their application as fiber-amplifier

Barium titanate-based bismuthate glasses doped with Er3+ ions have been fabricated by employing the conventional melt quench technique. Various characterization studies have been performed on the samples for their physical, structural and optical analysis such as the density and molar volume measurements, X-Ray diffraction (XRD), Fourier transform infrared (FTIR), Raman, and UV–Vis spectroscopies. The amorphous nature of the prepared glass samples has been confirmed by the broad humps observed in the X-Ray diffractograms. The FTIR spectra confirmed an increment in the non-bridging oxygen atoms (NBOs) and also the transformation of [BiO6] units to [BiO3] pyramidal units in the structural network of the glass matrix. Raman spectra in the high-frequency region have also been recorded which provided information related to the structural changes in the glass system upon the building of Er-O linkages. Absorption spectra of UV–Vis spectroscopy depicted six transition states such as 4F7/2, 2H11/2, 4S3/2, 4F9/2, 4I11/2, and 4I13/2. The spectroscopic and optical parameters such as energy band gap, optical conductivity, penetration depth, Judd-Ofelt (JO) parameters, refractive index, dielectric constant, Urbach energy, and transmission coefficient for the glasses have been determined, among others. The nephelauxetic ratio (β) and bonding parameters (δ) obtained from transitions of rare-earth ions have revealed the ionic character of the glasses. The calculated values of indirect and direct energy bandgap (Eg) of the prepared samples have been found to decrease from 2.04 to 1.93 and 2.67 to 2.45 resp. on increasing Er3+ ions. Judd-Ofelt (JO) parameters follow the order given by Ω2> Ω6> Ω4 and have been consistent with the literature. A decrement in the values of Ω2 from 3.761 to 2.699, confirmed the lowest asymmetry in the crystal field of rare-earth ions of glass system. The obtained values of refractive index, Urbach energy, dielectric constant, electronic & ionic polarizability and the metallization criterion suggest that the presently studied glass samples are amorphous semiconducting, optically non-linear and are suitable for the applications in erbium-doped fiber-amplifier (EDFA), lasers and optoelectronic devices.

Axon Initial Segments Are Required for Efficient Motor Neuron Axon Regeneration and Functional Recovery of Synapses.

The axon initial segment (AIS) generates action potentials and maintains neuronal polarity by regulating the differential trafficking and distribution of proteins, transport vesicles, and organelles. Injury and disease can disrupt the AIS, and the subsequent loss of clustered ion channels and polarity mechanisms may alter neuronal excitability and function. However, the impact of AIS disruption on axon regeneration after injury is unknown. We generated male and female mice with AIS-deficient multipolar motor neurons by deleting AnkyrinG, the master scaffolding protein required for AIS assembly and maintenance. We found that after nerve crush, neuromuscular junction reinnervation was significantly delayed in AIS-deficient motor neurons compared with control mice. In contrast, loss of AnkyrinG from pseudo-unipolar sensory neurons did not impair axon regeneration into the intraepidermal nerve fiber layer. Even after AIS-deficient motor neurons reinnervated the neuromuscular junction, they failed to functionally recover because of reduced synaptic vesicle protein 2 at presynaptic terminals. In addition, mRNA trafficking was disrupted in AIS-deficient axons. Our results show that, after nerve injury, an intact AIS is essential for efficient regeneration and functional recovery of axons in multipolar motor neurons. Our results also suggest that loss of polarity in AIS-deficient motor neurons impairs the delivery of axonal proteins, mRNAs, and other cargoes necessary for regeneration. Thus, therapeutic strategies for axon regeneration must consider preservation or reassembly of the AIS.SIGNIFICANCE STATEMENT Disruption of the axon initial segment is a common event after nervous system injury. For multipolar motor neurons, we show that axon initial segments are essential for axon regeneration and functional recovery after injury. Our results may help explain injuries where axon regeneration fails, and suggest strategies to promote more efficient axon regeneration.

Sparking Nano-Metals on a Surface of Polyethylene Terephthalate and Its Application: Anti-Coronavirus and Anti-Fogging Properties.

The nano-metal-treated PET films with anti-virus and anti-fogging ability were developed using sparking nano-metal particles of Ag, Zn, and Ti wires on polyethylene terephthalate (PET) films. Ag nanoparticles were detected on the PET surface, while a continuous aggregate morphology was observed with Zn and Ti sparking. The color of the Ag-PET films changed to brown with increasing repeat sparking times, but not with the Zn-PET and Ti-PET films. The water contact angle of the nano-metal-treated PET films decreased with increasing repeat sparking times. The RT-PCR anti-virus test confirmed the high anti-virus efficiency of the nano-metal-treated PET films due to the fine particle distribution, high polarity, and binding of the nano-metal ions to the coronavirus, which was destroyed by heat after UV irradiation. A highly transparent, anti-fogging, and anti-virus face shield was prepared using the Zn-PET film. Sparking was an effective technique to prepare the alternative anti-virus and anti-fogging films for medical biomaterial applications because of their low cost, convenience, and fast processing.