Broad Channel Research Articles

Composite photonic lattice with a broad channel to sustain topological interface states.

In the field of topological photonics, one goal is to seek specialized structures with topological protection that can support the stable propagation of light. We have designed a topological configuration featuring a broad channel to sustain edge or interface states. The topological properties are elucidated by analyzing the energy spectrum, eigenstates, and winding numbers. Furthermore, the propagation characteristics of light within our structure are examined through the computation of intensities derived from the coupled mode equations. Our findings reveal that the structure is capable of confining light to the central region, facilitating stable and robust propagation for large-sized beams. Additionally, simulations conducted using commercial software have substantiated the theoretical analysis. Our finding may have significant implications for the modulation of structured light and the development of photonic devices with wide channel capabilities.

High entropy induced lattice expansion in layered oxide cathode towards fast sodium storage

Although O3-type layered oxides have become viable cathode materials for sodium-ion batteries (SIBs) due to their high energy densities, they still suffer from narrow ion channels and serious structure degradation, severely jeopardizing their electrochemical properties. Here, a stable O3-type layered oxide NaNi0.4Mn0.4M0.2O2 (M= Fe, Cu, Mg, Ti, Sn) (HE-NaNM) was synthesized by a high-entropy doping strategy. Owing to the introduction of the metal cations with ionic radiuses in a range of 0.61-0.73 Å into the layered structure, the lattice is expanded from 15.94 to 16.03 Å in c-axis, associated with a high distortion of TMO6 octahedrons, offering broad channels for sodium-ion transport in the lattices. Moreover, such expanded lattices and highly distorted TMO6 octahedrons enable to efficiently restrain the migration of TM ions and the severe sliding of TMO2 slabs, affording one-step reversible structure evolution between O3 and P3 phase during sodium extraction/insertion without formation of harmful interphases. As a result, a good rate capability of 77.9 mAh g-1 at 10 C and a long-term cycling stability up to 400 cycles at 5 C are achieved for sodium storage.

Optical momentum distributions in monochromatic, isotropic random vector fields

Abstract We investigate the decomposition of the electromagnetic Poynting momentum density in three-dimensional random monochromatic fields into orbital and spin parts, using analytical and numerical methods. In sharp contrast with the paraxial case, the orbital and spin momenta in isotropic random fields are found to be identically distributed in magnitude, increasing the discrepancy between the Poynting and orbital pictures of energy flow. Spatial correlation functions reveal differences in the generic organization of the optical momenta in complex natural light fields, with the orbital current typically forming broad channels of unidirectional flow, and the spin current manifesting larger vorticity and changing direction over subwavelength distances. These results are extended to random fields with pure helicity, in relation to the inclusion of electric-magnetic democracy in the definition of optical momenta.

Intrinsic microporous poly(phenyl-alkane)s with pendent piperazinium for high performance anion exchange membrane fuel cells

Exploring anion exchange membranes (AEMs) with high conductivity and satisfactory stability is very meaningful for the advancement of alkaline fuel cells. Herein, a novel class of intrinsic microporous AEMs with pendent piperazinium are systematically fabricated for alkaline fuel cell performance testing. Contorted and rigid spirobisindane backbone structure expands the free volume of AEMs, inducing broad and interconnected ion transport channels. This unique feature endows membranes a leading advantage for the efficient transmission of hydroxide ions. Consequently, the prepared membrane displays excellent normalized hydroxide conductivity of 78.99 mS g cm−1 mmol−1 at 80 °C. Meanwhile, the hydroxide conductivity degrades by only 8.3 % after treatment in 1 M NaOH for 1000 h at 80 °C. Moreover, the peak power density of H2/O2 single cell employing this membrane exhibits 1.06 W cm−2 at 80 °C and the cell can preserve 93.0 % of its initial voltage after operating for 18 h.

Ultra-stable aqueous nickel-ion storage achieved by iron-ion pre-introduction assisted hydrated vanadium oxide cathode

Aqueous Nickel-ion batteries (ANIBs) are attracting growing attention for next-generation energy storage devices, but their development is hindered by deficient satisfactory cathode materials and undefined reaction mechanisms. Herein, a novel layered vanadium oxide with Fe3+-ions pillars (Fe0.29V2O5·0.57H2O, FVO) is developed and innovatively used for effective Ni2+ ion storage. The large interlayer spacing and abundant oxide vacancies of FVO can provide broad ion migration channels and rich ion storage sites. The pre-intercalated Fe3+-ions can firmly support the integrity of the layered structure by Fe-O bonds to achieve excellent cycle stability. RGO is further introduced to construct the FVO@G composite can improve the conductivity and stability of the FVO electrode. As a result, the FVO@G electrode exhibits exceptional Ni2+ storage performance of 169.8 mAh g−1 at 0.5C and ultrahigh capacity retention of 91.9% after 320 cycles at 10C. The Ni2+ storage mechanism in FVO@G is clarified by in-situ XRD and ex-situ Raman, ex-situ XPS techniques, the results show that FVO@G undergoes a phase transition accompanied by an expansion of the interlayer spacing upon the first charging, and the electrodes display a high degree of structural reversibility and a negligible volume expansion during the subsequent cycles. Furthermore, density functional theory (DFT) calculations show that FVO provides efficient diffusion paths along the b-axis with ultrafast transport kinetics. This work is a significant step in ANIBs research and provides valuable insights for the design of high-performance ANIBs cathode material.

Occupancy Analysis of Water Molecules inside Channels within 25 Å Radius of the Oxygen-Evolving Center of Photosystem II in Molecular Dynamics Simulations.

At room temperature and neutral pH, the oxygen-evolving center (OEC) of photosystem II (PSII) catalyzes water oxidation. During this process, oxygen is released from the OEC, while substrate waters are delivered to the OEC and protons are passed from the OEC to the lumen through water channels known as the narrow or the O4 channel, broad or the Cl1 channel, and large or the O1 channel. Protein residues lining the surfaces of these channels play a critical role in stabilizing the hydrogen-bonding networks that assist in the process. We carried out an occupancy analysis to better understand the structural and possible substrate water dynamics in full PSII monomer molecular dynamics (MD) trajectories in both the S1 and S2 states. We find that the equilibrated positions of water molecules derived from MD-derived electron density maps largely match the experimentally observed positions in crystallography. Furthermore, the occupancy reduction in MD simulations of some water molecules inside the single-filed narrow channel also correlates well with the crystallographic data during a structural transition when the S1 state of the OEC advances to the S2 state. The overall reduced occupancies of water molecules are the source of their "vacancy-hopping" dynamic nature inside these channels, unlike water molecules inside an ice lattice where all water molecules have a fixed unit occupancy. We propose on the basis of findings in our structural and molecular dynamics analysis that the water molecule occupying a pocket formed by D1-D61, D1-S169, and O4 of the OEC could be the last steppingstone to enter into the OEC and that the broad channel may be favored for proton transfer.

Regulation of calcium entry by cyclic GMP signaling in Toxoplasma gondii

Ca2+ signaling impacts almost every aspect of cellular life. Ca2+ signals are generated through the opening of ion channels that permit the flow of Ca2+ down an electrochemical gradient. Cytosolic Ca2+ fluctuations can be generated through Ca2+ entry from the extracellular milieu or release from intracellular stores. In Toxoplasma gondii, Ca2+ ions play critical roles in several essential functions for the parasite, like invasion of host cells, motility, and egress. Plasma membrane Ca2+ entry in T.gondii was previously shown to be activated by cytosolic calcium and inhibited by the voltage-operated Ca2+ channel blocker nifedipine. However, Ca2+ entry in T.gondii did not show the classical characteristics of store regulation. In this work, we characterized the mechanism by which cytosolic Ca2+ regulates plasma membrane Ca2+ entry in extracellular T.gondii tachyzoites loaded with the Ca2+ indicator Fura-2. We compared the inhibition by nifedipine with the effect of the broad spectrum TRP channel inhibitor, anthranilic acid or ACA, and we find that both inhibitors act on different Ca2+ entry activities. We demonstrate, using pharmacological and genetic tools, that an intracellular signaling pathway engaging cyclic GMP, protein kinase G, Ca2+, and the phosphatidyl inositol phospholipase C affects Ca2+ entry and we present a model for crosstalk between cyclic GMP and cytosolic Ca2+ for the activation of T.gondii's lytic cycle traits.

In-situ sodium chloride template synthesis of γ-WO3 hollow cubes for high-sensing and dual-selective hydrazine/dibutylamine detection at different temperatures

The fabrication of a chemiresistive sensor with dual-selectivity to highly toxic and explosive N2H4/dibutylamine (DBA) remains challenging due to no report. To this aim, we synthesized uniform (NH4)0.33WO3 cuboid precursors through optimized solvothermal reaction and in-situ formed NaCl template. Subsequently, the precursors were calcined in air to transform into γ-WO3 hollow cubes (WO3-HC) assembled from near-spherical nanoparticles, and the effect of calcination temperature on microstructures and gas-sensing properties was investigated. Among, WO3-HC-5 obtained by calcining precursor at 500 °C has broad pore channels, large specific surface area and abundant oxygen vacancy defects. Under the catalytic synergy of surface W6+ Lewis acid with dangling bonds, WO3-HC-5 sensor realizes the bifunctional monitoring of N2H4 and DBA. It presents large response value (S = 606.6) to 100 ppm N2H4 at 50 °C and a good response (S = 76.7) to the same concentration of DBA at 217 °C, and has fast response rate, low practical detection limit, satisfactory stability and humidity resistance. WO3-HC-5 represents the first metal oxide-based sensor with dual-selectivity towards aforementioned harmful gases at different operating temperatures. Moreover, the bifunctional mechanism has been characterized and analyzed in detail.

Snap-through dynamics of a buckled flexible filament in a channel flow

The flow-induced snap-through dynamics of a buckled flexible filament in a channel flow was explored using the penalty immersed boundary method. Two edge condition distributions were considered for comparison. One edge condition was a simply supported leading edge and a clamped trailing edge (SC); the other condition was two clamped edges. The effects of channel height and bending rigidity on the energy harvesting performance were systematically examined. The presence of the channel wall compresses the activation space of the vortex, leading to the formation of a high shear flow near the wall, which, in turn, strongly influences the wake pattern. In the snap-through oscillation mode, a wake pattern of 2S + 2P is observed in both narrow and broad channels, whereas the mechanism of vortex shedding varies between the two cases. Both cases demonstrate greater critical rigidity and greater elastic energy compared with conditions under external flow, suggesting an enhancement of the energy harvesting performance. The greater energy harvesting ability of the SC case is derived from both the larger deflection and the higher strain energy in this system. The wall effect is inversely proportional to the channel height, becoming nearly negligible when the nondimensional channel height exceeds 2. These findings provide valuable insights into the dynamics of flexible filaments in the channel flow and their potential for energy harvesting applications.

From Sheep Track to Motorway: Supramolecular-Mediated 2D Nanofluidic Channels for Ultrafast Water Transport.

Atomic thick 2D materials hold great potential as building blocks to construct highly permeable membranes, yet the permeability of laminar 2D material membranes is still limited by their irregularity sheep track-like interlayer channels. Herein, a supramolecular-mediated strategy to induce the regular assembly of high-throughput 2D nanofluidic channels based on host-guest interactions is proposed. Inspired by the characteristics of motorways, supramolecular-mediated ultrathin 2D membranes with broad and continuous regular water transport channels are successfully constructed using graphene oxide (GO) as an example. The prepared membrane achieves an ultrahigh water permeability (369.94LMHbar-1) more than six times higher than that of the original membranes while maintaining dye rejection above 98.5%, which outperforms the reported 2D membranes. Characterization and simulation results show that the introduction of hyaluronate-grafted β-cyclodextrin not only expands the interlayer channels of GO membranes but also enables the membranes to operate stably under harsh conditions with the help of host-guest interactions. This universal supramolecular assembly strategy provides new opportunities for the preparation of 2D membranes with high separation performance and reliable and stable nanofluidic channels.

Effects of spectral smearing on speech understanding and masking release in simulated bilateral cochlear implants.

Differences in spectro-temporal degradation may explain some variability in cochlear implant users' speech outcomes. The present study employs vocoder simulations on listeners with typical hearing to evaluate how differences in degree of channel interaction across ears affects spatial speech recognition. Speech recognition thresholds and spatial release from masking were measured in 16 normal-hearing subjects listening to simulated bilateral cochlear implants. 16-channel sine-vocoded speech simulated limited, broad, or mixed channel interaction, in dichotic and diotic target-masker conditions, across ears. Thresholds were highest with broad channel interaction in both ears but improved when interaction decreased in one ear and again in both ears. Masking release was apparent across conditions. Results from this simulation study on listeners with typical hearing show that channel interaction may impact speech recognition more than masking release, and may have implications for the effects of channel interaction on cochlear implant users' speech recognition outcomes.

Vanadium dissolution restraint and conductive assistant in MnV12O31·10H2O to boost energy storage property for aqueous zinc-ion batteries

Hydrated vanadates have gained significant attentions as cathode ingredients for aqueous zinc-ion batteries (AZIBs) on account of their broad open channels in the structural framework together with the existence of crystal water for stabilizing the structure. Yet, the ambiguous zinc storage mechanism and sluggish electrochemical reaction dynamics are always challenging questions for the development of hydrated vanadate cathodes. Herein, a novel hydrated manganese vanadate MnV12O31·10H2O (MVOH) nanobelt assembled microparticle materials is synthesized and combined with carbon nanofibers (CNFs) to generate MVOH-CNFs composite through electrostatic attraction in the condition of hydrothermal environment. The zinc storage mechanism of the formed MVOH substance as a cathode for AZIBs is clarified by a combined in- and ex-situ characterizations. The advantages of the crystal structure of MVOH to restrain vanadium dissolution and the assistance of CNFs to meliorate reaction kinetics are clarified based on the density functional theory calculations. The MVOH-CNFs cathode with a CNF content of 10.1% exhibits a reversible capacity of 302 mAh g−1 at 2 A g−1 after 100 cycles and 105 mAh g−1 at 8 A g−1 after 5000 cycles with robust structural stability. It also delivers excellent areal and volumetric capacity especially at high current density. A quasi-solid MVOH-CNFs//Zn pouch battery based on a gel electrolyte exhibits stable electrochemical performance and could be curled into a circular shape on the wrist to power a smart watch. This work paves a way for the furtherance of hydrated manganese vanadate cathodes in the application of high performance AZIBs.

Translocation Dynamics of an Active Filament through a Long-Length Scale Channel.

Active filament translocation through a confined space is crucial for diverse biological processes. By using Langevin dynamics simulations, we investigate the translocation dynamics of an axially self-propelled chain through a channel. First, results show a suggestive reciprocal scaling of translocation time versus active force. Second, in the case of a long channel, we demonstrate a very intriguing nonmonotonic change of translocation time with increasing channel width. The driving force shows a similar trend, providing a consistent picture to understand the unexpected channel width effect. In particular, in a moderately broad channel, the disordered chain conformation results in a loss of driving force and thus inhibits translocation dynamics. Chain adsorption might occur in a wide channel, which accounts for a facilitated translocation. Lastly, we connect the translocation process to tension propagation (TP). A modified TP picture is proposed to interpret the waiting time distribution. Our work highlights the new phenomenology owing to the crucial interplay of activity and spacial confinement, which drives the translocation dynamics, going beyond the traditional entropic barrier scenario.

GluN2A mediates ketamine-induced rapid antidepressant-like responses.

Ketamine was thought to induce rapid antidepressant responses by inhibiting GluN2B-containing N-methyl-D-aspartic acid (NMDA) receptors (NMDARs), which presents a promising opportunity to develop better antidepressants. However, adverse side effects limit the broader application of ketamine and GluN2B inhibitors are yet to be approved for clinical use. It is unclear whether ketamine acts solely through GluN2B-dependent mechanisms. The present study reports that the loss of another major NMDAR subunit, GluN2A, in adult mouse brains elicits robust antidepressant-like responses with limited impact on the behaviors that mimic the psychomimetic effects of ketamine. The antidepressant-like behavioral effects of broad NMDAR channel blockers, such as ketamine and MK-801 (dizocilpine), were mediated by the suppression of GluN2A, but not by the inhibition of GluN2B. Moreover, treatment with ketamine or MK-801 rapidly increased the intrinsic excitability of hippocampal principal neurons through GluN2A, but not GluN2B. Together, these findings indicate that GluN2A mediates ketamine-triggered rapid antidepressant-like responses.

PEMANFAATAN MACHINE LEARNING UNTUK PRICE OPTIMATION DENGAN MENGGUNAKAN MODEL ARTIFICIAL NEURAL NETWORK

A company's marketing strategy is not just product development, broad distribution channels, and promotions, but also pricing that is attractive and affordable to consumers. PT Asia Garment, which is engaged in the garment accessories industry, determines the price by looking at the quality of the product, the efficient level of processing time, and the difficulty level of the process. Generally, errors in pricing cause production costs to not match the selling price, the selling prices are rarely reviewed even though the market is constantly changing, and selling prices are determined separately. The research purpose is to utilize machine learning to determine the optimum selling price using the Artificial Neural Network Model. As a result, the predictions can produce an output accuracy of 87%, which is satisfying accuracy.

Peran Media Massa Dalam Memoderasi Dialog Politik

The mass media plays an important role in moderating political dialogue in society. This study aims to examine the role of the mass media in facilitating political dialogue, observe its impact on public participation, and analyze the challenges and opportunities faced by the mass media in carrying out this role. This research approach is a literature study and media content analysis. The findings of this study provide important insights into the role of the mass media as a mediator in constructive political dialogue. Based on the analysis of the literature, this research finds that the mass media has a major role in facilitating political dialogue. The mass media provide a broad platform and communication channel for the exchange of ideas, views and political information. Through balanced reporting, in-depth analysis, and presenting diverse perspectives, the mass media can help moderate political dialogue with the aim of achieving shared understanding, increasing public participation, and forming informational public opinion.

Catalytic resilience of multicomponent aromatic ring-hydroxylating dioxygenases in Pseudomonas for degradation of polycyclic aromatic hydrocarbons

Hydrophobic organic compounds, either natural or introduced through anthropogenic activities, pose a serious threat to all spheres of life, including humankind. These hydrophobic compounds are recalcitrant and difficult to degrade by the microbial system; however, microbes have also evolved their metabolic and degradative potential. Pseudomonas species have been reported to have a multipotential role in the biodegradation of aromatic hydrocarbons through aromatic ring-hydroxylating dioxygenases (ARHDs). The structural complexity of different hydrophobic substrates and their chemically inert nature demands the explicit role of evolutionary conserved multicomponent enzyme ARHDs. These enzymes catalyze ring activation and subsequent oxidation by adding two molecular oxygen atoms onto the vicinal carbon of the aromatic nucleus. This critical metabolic step in the aerobic mode of degradation of polycyclic aromatic hydrocarbons (PAHs) catalyzed by ARHDs can also be explored through protein molecular docking studies. Protein data analysis enables an understanding of molecular processes and monitoring complex biodegradation reactions. This review summarizes the molecular characterization of five ARHDs from Pseudomonas species already reported for PAH degradation. Homology modeling for the amino acid sequences encoding the catalytic α-subunit of ARHDs and their docking analyses with PAHs suggested that the enzyme active sites show flexibility around the catalytic pocket for binding of low molecular weight (LMW) and high molecular weight (HMW) PAH substrates (naphthalene, phenanthrene, pyrene, benzo[α]pyrene). The alpha subunit harbours variable catalytic pockets and broader channels, allowing relaxed enzyme specificity toward PAHs. ARHD's ability to accommodate different LMW and HMW PAHs demonstrates its 'plasticity', meeting the catabolic demand of the PAH degraders.

Microporous framework polar silicate-germanates with a wide isomorphic substitution: (K2.9Cs0.1)(Sc0.7In0.3)[(Si2.95Ge0.05)O9]·H2O and (K2.16Cs0.84)Bi[(Si1.5Ge1.5)O9]·H2O

Abstract New silicate-germanates (K2.9Cs0.1)(Sc0.7In0.3)[(Si2.95Ge0.05)O9]·H2O and (K2.16Cs0.84)Bi[(Si0.5Ge0.5)3O9]·H2O have been synthesized in multi-component systems under mild hydrothermal conditions. The new compounds are classified as new representatives of close related K3ScSi3O9·H2O parent structure, sp. gr. Pmn21. Their structural and isomorphic peculiarities are compared with it as well as with earlier investigated K1.46Pb1.54Сa[(Ge0.23Si0.77)3O9](ОН)0.54·0.46Н2О. Together with other known compounds, silicate-germanates form the extensive family A3M[T3O9]·H2O, A = K, Cs, Ca, Pb; M = Ho, Sc, Lu, Tb, Er, Y, Bi, Pb, In; T = Si, Ge, with a mixed microporous framework combined of M-octahedra and T-tetrahedra. Large alkali metal or/and Ca, Pb cations fill broad framework channels with cross-section up to 7.3 Å. Because of wide isomorphic substitution in the channels, and in tetrahedra and octahedra, ion exchange properties in the family are expected. Due to polar symmetry, all the crystals possess second-order nonlinearity which was confirmed with positive SHG tests for four compositions. Powder SHG experiments demonstrated moderate second harmonic intensities of order of α-quartz standard signals.

Impact of dynamic factors on the exchange flow between two neighboring bays with contrasting topography during summer: A numerical study

A high-resolution, three-dimensional numerical ocean model was employed to understand the exchange flow through Noryang Channel, which connects Gwangyang Bay and Jinju Bay. These two bays exhibit contrasting topographies, with Gwangyang Bay connected to the open ocean through a broad and deep channel, whereas Jinju Bay is relatively isolated from the open ocean by a narrow and shallow channel. Numerical experiments were conducted to determine the contribution of river discharge, wind stress, surface heat flux, and tides to the exchange flow between the two bays during summer. The results suggested that river discharge was the dominant factor affecting the exchange flow along Noryang Channel. Particularly, a high river discharge during summer increased the sea level in Jinju Bay, creating a barotropic flow toward Gwangyang Bay. However, the dense water entering Gwangyang Bay through the wide and deep channel generated a baroclinic flow toward Jinju Bay along the lower layer of Noryang Channel. An analytical model supported the conclusion that river discharge is the main driver of the exchange flow in Noryang Channel.

Thermal magnetic analysis on iron ores and banded iron formations (BIFs) in the Hamersley Province: Implications of origins of magnetic minerals and iron ores

<abstract> <p>The genesis models of the iron-ores hosted in banded iron formations (BIFs) in the Hamersley Province of Western Australia have been debated since the iron-ore deposits were discovered in the 1960s. The existing models considered the few physicochemical conditions for the iron-ore enrichment from BIFs. This study incorporates the latest research outcomes in conversions among the major magnetic minerals under different physicochemical conditions with the thermal magnetic analysis for BIFs and iron-ores collected from the Hamersley Province to fill the gap in knowledge highlighted by existing studies of the iron ores and BIFs. The results indicate that the high-grade hematite ores might have been undergone a physicochemical process under hydrothermal conditions between 120 ℃ and 220 ℃ during the major stage of enrichment from the original BIFs in the Brockman Iron Formation. Such physicochemical conditions would require either that the BIF units were buried 4000–5000 m underground with tilted broad channels formed by large-scale deformation in the region that facilitates hydrothermal reactions and leaching by the fluids flowing down deep to 4000–5000 m, somehow similar to the deep-seated supergene model proposed in previous works, or that the BIF units were still buried but the hydrothermal fluids coming up from deeper sources spread widely over the broad channels to ensure the high-grade hematite ores are consistently uniform over the entire deposit. The large-scale martite-goethite deposits in the Marra Mamba Iron Formation might be derived from multiple supergene phases from hematite-martite ores below 100 ℃ in the natural process of oxidization near surface, somewhat similar to the existing model for the channel iron deposits. Magnetite contained within current BIFs and iron ores was least likely derived from primary hematite in BIFs.</p> </abstract>