Insertion Of Channels Research Articles

Compact Silicon-Arrayed Waveguide Gratings with Low Nonuniformity.

Array waveguide gratings (AWGs) have been widely used in multi-purpose and multi-functional integrated photonic devices for Microwave photonics (MWP) systems. In this paper, we compare the effect of output waveguide configurations on the performance of AWGs. The AWG with an output waveguide converging on the grating circle had larger crosstalk and lower nonuniformity. We also fabricated a 1 × 8 AWG with an output waveguide converging onto the SOI's grating circle, whose central operation wavelength was around 1550 nm. The fabricated AWG has a chip size of 500 μm × 450 μm. Experimental results show that the adjacent channel crosstalk is -12.68 dB. The center channel insertion loss, as well as 3 dB bandwidth, are 4.18 dB and 1.22 nm at 1550 nm, respectively. The nonuniformity is about 0.494 dB, and the free spectral range is 19.4 nm. The proposed AWG is expected to play an important role in future MWP systems given its good nonuniformity and insertion loss level.

Photonic-crystal-based hybrid wavelength-mode division multiplexer for SOI platforms

This paper presents a 12-channel hybrid wavelength-mode division multiplexer (WDM-MDM) based on 2D photonic crystals. The proposed device consists of microring resonators (MRRs) and asymmetric directional couplers (ADCs) to perform three-channel wavelength division multiplexing and four-channel mode division multiplexing operations, respectively. Each MRR can work bi-directionally, providing the same wavelength channels separately in two drop ports. The bus waveguides in the cascaded ADCs are optimized to convert the fundamental modes to the corresponding higher-order modes and are connected through taper regions for the smooth transition of modes. The designed device is simulated using the finite-difference time-domain solver, achieving a maximum channel spacing and insertion loss of 5.05 nm and 0.97 dB, respectively. The device size of the proposed WDM-MDM is 74.98µm×32.82µm. The fabrication tolerance study is performed for uniform over-etch and under-etch conditions. The temperature tolerance study on the resonant wavelength is performed, and the temperature coefficient shift of <0.0254nm/K is achieved. The proposed device can potentially increase the channel capacity for on-chip high-density optical interconnects.

Vortex characteristics inside profile reed channel of an air-jet loom based on large eddy simulation

In the process of jet weaving, airflow plays a primary role by carrying the weft yarns and interlacing them with the warp yarns to form the fabric. The vortex characteristics within the weft insertion channel of an air-jet loom directly affect the motion of the weft yarns, thus impacting the quality of the fabric. In this study, the large eddy simulation (LES) method was employed, and the Omega vortex identification criterion was used to analyze the vortex characteristics within the profile reed channel. The effects of different positions of relay nozzles, nozzle spacing, and reed gap ratio on the airflow characteristics were investigated. Additionally, the vortex volume ratio () and velocity fluctuation rate () were introduced as indicators to measure the proportion of vortices and the turbulence intensity of the airflow field. The numerical results indicated that the introduction of relay nozzles significantly reduced the intensity of airflow vortices and the proportion of vortices within the profile reed channel. When the inlet pressures of the main and relay nozzles were fixed, the minimum values of and were observed when the first relay nozzle was located at 105 mm, the nozzle spacing was 65 mm, and the gap ratio was 1:2. The findings of this study provide theoretical guidance for further improving the airflow characteristics within the profile reed channel of an air-jet looms.

Peptide Lv Promotes Trafficking and Membrane Insertion of KCa3.1 through the MEK1-ERK and PI3K-Akt Signaling Pathways.

Peptide Lv is a small endogenous secretory peptide that is proangiogenic through hyperpolarizing vascular endothelial cells (ECs) by enhancing the current densities of KCa3.1 channels. However, it is unclear how peptide Lv enhances these currents. One way to enhance the current densities of ion channels is to promote its trafficking and insertion into the plasma membrane. We hypothesized that peptide Lv-elicited KCa3.1 augmentation occurs through activating the mitogen-activated protein kinase kinase 1 (MEK1)-extracellular signal-regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K)-protein kinase B (Akt) signaling pathways, which are known to mediate ion channel trafficking and membrane insertion in neurons. To test this hypothesis, we employed patch-clamp electrophysiological recordings and cell-surface biotinylation assays on ECs treated with peptide Lv and pharmaceutical inhibitors of ERK and Akt. Blocking ERK or Akt activation diminished peptide Lv-elicited EC hyperpolarization and increase in KCa3.1 current densities. Blocking PI3K or Akt activation decreased the level of plasma membrane-bound, but not the total amount of KCa3.1 protein in ECs. Therefore, the peptide Lv-elicited EC hyperpolarization and KCa3.1 augmentation occurred in part through channel trafficking and insertion mediated by MEK1-ERK and PI3K-Akt activation. These results demonstrate the molecular mechanisms of how peptide Lv promotes EC-mediated angiogenesis.

The exocyst complex is required for the trafficking and delivery of KCa3.1 to the basolateral membrane of polarized epithelia.

Control of the movement of ions and water across epithelia is essential for homeostasis. Changing the number or activity of ion channels at the plasma membrane is a significant regulator of epithelial transport. In polarized epithelia, the intermediate-conductance calcium-activated potassium channel, KCa3.1 is delivered to the basolateral membrane where it generates and maintains the electrochemical gradients required for epithelial transport. The mechanisms that control the delivery of KCa3.1 to the basolateral membrane are still emerging. Herein, we investigated the role of the highly conserved tethering complex exocyst. In epithelia, exocyst is involved in the tethering of post-Golgi secretory vesicles with the basolateral membrane, which is required before membrane fusion. In our Fisher rat thyroid cell line that stably expresses KCa3.1, siRNA knockdown of either of the exocyst subunits Sec3, Sec6, or Sec8 significantly decreased KCa3.1-specific current. In addition, knockdown of exocyst complex subunits significantly reduced the basolateral membrane protein level of KCa3.1. Finally, co-immunoprecipitation experiments suggest associations between Sec6 and KCa3.1, but not between Sec8 and KCa3.1. Collectively, based on these data and our previous studies, we suggest that components of exocyst complex are crucially important in the tethering of KCa3.1 to the basolateral membrane. After which, Soluble N-ethylmaleimide-sensitive factor (SNF) Attachment Receptors (SNARE) proteins aid in the insertion of KCa3.1-containing vesicles into the basolateral membrane of polarized epithelia.NEW & NOTEWORTHY Our Ussing chamber and immunoblot experiments demonstrate that when subunits of the exocyst complex were transiently knocked down, this significantly reduced the basolateral population and functional expression of KCa3.1. These data suggest, combined with our protein association experiments, that the exocyst complex regulates the tethering of KCa3.1-containing vesicles to the basolateral membrane prior to the SNARE-dependent insertion of channels into the basolateral membrane of epithelial cells.

Focus on software, data acquisition, and instrumentation

Focus on software, data acquisition, and instrumentation

On the Size of Balls and Anticodes of Small Diameter Under the Fixed-Length Levenshtein Metric

The rapid development of DNA storage has brought the deletion and insertion channel to the front line of research. When the number of deletions is equal to the number of insertions, the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Fixed Length Levenshtein</i> (FLL) metric is the right measure for the distance between two words of the same length. Similar to any other metric, the size of a ball is one of the most fundamental parameters. In this work, we consider the minimum, maximum, and average size of a ball with radius one, in the FLL metric. The related minimum and the maximum size of a maximal anticode with diameter one are also considered.

TRPC1 channel clustering during store-operated Ca2+ entry in keratinocytes.

Skin is the largest organ in the human body with ∼95% of its surface made up of keratinocytes. These cells maintain a healthy skin barrier through regulated differentiation driven by Ca2+-transcriptional coupling. Many important skin conditions arise from disruption of this process although not all stages are fully understood. We know that elevated extracellular Ca2+ at the skin surface is detected by keratinocyte Gαq-coupled receptors that signal to empty endoplasmic reticulum Ca2+ stores. Orai channel store-operated Ca2+ entry (SOCE) and Ca2+ influx via "canonical" transient receptor potential (TRPC)-composed channels then activates transcription factors that drive differentiation. While STIM-mediated activation of Orai channels following store depletion is well defined, how TRPC channels are activated is less clear. Multiple modes of TRPC channel activation have been proposed, including 1) independent TRPC activation by STIM, 2) formation of Orai-TRPC-STIM complexes, and 3) the insertion of constitutively-active TRPC channels into the membrane during SOCE. To help distinguish between these models, we used high-resolution microscopy of intact keratinocyte (HaCaT) cells and immunogold transmission electron microscopy (TEM) of HaCaT plasma membrane sheets. Our data shows no evidence of significant insertion of Orai1 or TRPC subunits into the membrane during SOCE. Analysis of transmission electron microscopy data shows that during store-depletion and SOCE, Orai1 and TRPC subunits form separate membrane-localized clusters that migrate towards each other. This clustering of TRPC channel subunits in keratinocytes may support the formation of TRPC-STIM interactions at ER-plasma membrane junctions that are distinct from Orai-STIM junctions.

Coarse-grained methods for heterogeneous vesicles with phase-separated domains: Elastic mechanics of shape fluctuations, plate compression, and channel insertion

We develop coarse-grained particle approaches for studying the elastic mechanics of vesicles with heterogeneous membranes having phase-separated domains. We perform simulations both of passive shape fluctuations and of active systems where vesicles are subjected to compression between two plates or subjected to insertion into narrow channels. Analysis methods are developed for mapping particle configurations to continuum fields with spherical harmonics representations. Heterogeneous vesicles are found to exhibit rich behaviors where the heterogeneity can amplify surface two-point correlations, reduce resistance during compression, and augment vesicle transport times in channels. The developed methods provide general approaches for characterizing the mechanics of coarse-grained heterogeneous systems taking into account the roles of thermal fluctuations, geometry, and phase separation.

An integrated device for electro-optic modulation and dense wavelength division multiplexing based on photonic crystals

We proposed an integrated device for electro-optic (EO) modulation and dense wavelength division multiplexing (DWDM) based on photonic crystals (PhCs). The transmittance performance of the designed structure was modelled and analyzed according to the time-domain coupled mode theory (CMT), using three-dimensional finite-difference time-domain (3D-FDTD) method to calculate the parameters of the proposed device for verification. The numerical results show that the proposed integrated device can realize the functions of “on”, “off” modulation and DWDM with a channel spacing of 0.8 nm at the operating wavelengths of 1555 nm and 1554.2 nm. The minimum insertion loss, channel crosstalk and modulation voltage are 0.7 dB, − 29.04 dB and 0.88 V, respectively. The maximum extinction ratio and modulation speed are 21.51 dB and 29.4 GHz. The designed integrated device has the advantages of low loss, compact size (41.28μm×11.18μm), narrow channel spacing, large extinction ratio, which can be easily expanded the number of channels and used in highly integrated large-capacity optical communication systems and data center.

Concatenated Codes for Multiple Reads of a DNA Sequence

Decoding sequences that stem from multiple transmissions of a codeword over an insertion, deletion, and substitution channel is a critical component of efficient deoxyribonucleic acid (DNA) data storage systems. In this paper, we consider a concatenated coding scheme with an outer nonbinary low-density parity-check code or a polar code and either an inner convolutional code or a time-varying block code. We propose two novel decoding algorithms for inference from multiple received sequences, both combining the inner code and channel to a joint hidden Markov model to infer symbolwise a posteriori probabilities (APPs). The first decoder computes the exact APPs by jointly decoding the received sequences, whereas the second decoder approximates the APPs by combining the results of separately decoded received sequences and has a complexity that is linear with the number of sequences. Using the proposed algorithms, we evaluate the performance of decoding multiple received sequences by means of achievable information rates and Monte-Carlo simulations. We show significant performance gains compared to a single received sequence. In addition, we succeed in improving the performance of the aforementioned coding scheme by optimizing both the inner and outer codes.

Combined electrical and fluorescence recordings of single molecules in bilayers formed on MECA-opto chips.

Molecular processes within lipid bilayers, such as ion channel insertion and gating, can be followed using electrophysiology techniques. With fluorescently labeled molecules, additional features such as protein aggregation and spatial distribution can also be followed. However, correlated electrical and optical measurements, especially at the single-molecule level, have been historically challenging. Factors such as bilayer stability, the timing of protein aggregation and insertion, and the photostability of fluorescent dyes, all work against successful collection of simultaneous electrical and fluorescence records. Here, we describe approaches for assessing lateral diffusion, single-molecule aggregation, and ion channel insertion in bilayers formed on commercially available micro-electrode cavity arrays (MECA-opto chips). These array chips have been specifically designed to enhance the collection of simultaneous electrical and optical records. We compare lipid and ion-channel diffusion results from both fluorescence correlation spectroscopy and wide-field single-molecule tracking experiments. We also use both approaches to assess protein aggregation, spatial distribution, and correlation with insertion currents in the bilayer.

Construction of phosphorus-doping with spontaneously developed selenium vacancies: Inducing superior ion-diffusion kinetics in hollow Cu2Se@C nanospheres for efficient sodium storage

Achieving high-efficiency sodium storage in metal selenides is still severely constrained in consideration of their inferior electronic conductivity and inadequate Na+ insertion pathways and active sites. Heteroatom doping accompanied by spontaneously developed lattice defects can effectively tune electronic structure of metal selenides, which give a strong effect to motivate fast charge transfer and Na+ accessibility. Herein, we finely designed and successfully constructed a fascinating phosphorus-doped Cu2Se@C hollow nanosphere with abundant vacancy defects (Cu2PxSe1−x@C) through a combination strategy of selenization of Cu2O nanosphere template, self-polymerization of dopamine, and subsequent phosphorization treatment. Such exquisite composite possesses enriched active sites, superior conductivity, and sufficient Na+ insertion channel, which enable much faster Na+ diffusion rates and more remarkable pseudocapacitive features. Satisfyingly, the Cu2PxSe1−x@C composites manifest the supernormal sodium-storage capabilities, that is, a reversible capacity of 403.7 mA h g−1 at 1.0 A g−1 over 100 cycles, and an ultrastable cyclic lifespan over 1000 cycles at 20.0 A g−1 with a high capacity-retention of about 249.7 mA h g−1. The phase transformation of the Cu2PxSe1−x@C involving the intercalation of Na+ into Cu2Se and the following conversion of NaCuSe to Cu and Na2Se were further demonstrated through a series of ex-situ characterization methods. DFT results demonstrate that the coexistence of phosphorus-doping and vacancy defects within Cu2Se results in the reduction of Na+ adsorption energy from −1.47 to −1.56 eV improving the conductivity of Cu2Se to further accelerate fast Na+ mobility.

Low-Loss Silicon Photonic 16 × 16 Cyclic AWGR Based on SOI Platform

We experimentally demonstrate a low-loss and low-crosstalk 16-channel 200 GHz-channel-spacing arrayed waveguide grating router (AWGR) with a size of 0.67 × 0.37 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , targeting for C-band wavelength division multiplexing (WDM) interconnect routing applications. As a result, the AWGR features a channel spacing of 200±10 GHz, a free spectral range of 25.62 nm and a 3 dB channel bandwidth of 0.9 nm. Based on comprehensive optimal design, the measured characterization revealed 5.55 dB maximum channel loss non-uniformity with 1.13 dB best-case channel insertion loss. Besides, the fabricated device exhibits good cyclic-frequency operation for all 16 × 16 port combinations with channel crosstalk of –15.11 dB.

A generalized approach to estimation of memoryless covert channel information leakage capacity

Estimating the amount of information that is leaked by covert channels is a necessity to comprehend and mitigate the severity of attacks exploiting these channels. Having such an estimation in design-state provides an opportunity for designers to adjust their systems to minimize information leakage. In this paper, we propose a methodology to estimate the worst-case information leakage (or capacity for the information leakage) through various memoryless covert channels – both analog and digital ones – exhibiting on–off keying structure. In that respect, we first model the communication channel as a deletion–insertion channel to account for the information losses due to software activities. Then, we derive the effective noise in covert channels as the combination of jitter noise caused by signaling time variation and Additive White Gaussian Noise (AWGN). Considering this effective noise, we propose a communication model which can be generalized for various covert channels and takes insertions, deletions, and asynchronous nature of covert channels into account. By leveraging the link between this communication model and information theory literature, we obtain the information leakage capacity that reveals the leakage limit for the worst-case scenarios. Finally, we provide experimental results to demonstrate that the proposed model is an effective and a generalized methodology to score the resilience of a given system to covert channel attacks.

Abstract 1071: Efficacy of targeted osmotic lysis using pulsed electric field stimulation compared to paclitaxel for treating murine, triple-negative breast carcinoma

Abstract Targeted osmotic lysis (TOL), the concurrent stimulation of voltage-gated sodium channels (VGSCs) and blockade of Na+ pumps, kills up to 100% of highly malignant, human and murine breast cancer cells in vitro and slows the growth of murine breast cancer homografts and increases survival of the hosts in vivo when compared to homografts treated with negative controls. In this study we compared the efficacy of TOL and paclitaxel, a current standard chemotherapeutic agent for treating advanced murine breast cancer, as a positive control. For this, BALB/c mice with 4T1 homografts were treated with TOL alone, paclitaxel alone or with a combination regimen of paclitaxel and TOL. For TOL, mice received 8 hourly doses (3 mg/kg) of digoxin on 2 successive days. Upon reaching steady-state levels (dose 5) the mice were exposed to 4 X 30 minutes of pulsed electric field stimulation (18 V/m, 10 ms pulses, 15 interstimulus intervals) hourly for a total of 2 hours of stimulation. Alternatively, mice received paclitaxel (20 mg/kg) by i.p. injection. Mice that were treated concurrently with TOL and paclitaxel received paclitaxel 2 days prior to treatment with TOL. Groups of mice that received digoxin alone, stimulation alone, paclitaxel + digoxin, paclitaxel + stimulation or vehicle alone served as negative controls. Initially, the homografts were measured daily and then every other day with a digital caliper until criteria for humane endpoint euthanasia were met. The mean time to meeting criteria for humane endpoint euthanasia in mice treated with paclitaxel alone (2 days) was identical to that observed in the negative controls. Mice treated with TOL alone, on average, met criteria at post-treatment day 5, whereas administration of paclitaxel two days before TOL reduced the effectiveness of TOL, decreasing mean survival to day 3 post-treatment. Immunohistochemical evidence indicated that paclitaxel’s effect on tubulin may impede the transport and insertion of channels into the cell membrane, thereby reducing the channel density and the effectiveness of TOL. By contrast, the administration of TOL either before or after treatment with paclitaxel improved host survival. Normal tissues were unaffected. These results are evidence that TOL is equal to or better than paclitaxel for increasing survival of murine hosts with advanced breast cancer when TOL is administered before or between paclitaxel dosing cycles. Sequential use of TOL may well improve survival, but simultaneous administration of paclitaxel and TOL will likely reduce TOL’s adjunctive benefit. Because of the conserved nature of the sodium channel/sodium pump mechanism, the comparable efficacy to TOL to a currently approved treatment and the favorable adverse effect profile, we submit that TOL warrants further study as a promising option for treating individuals with advanced neoplastic disease. Citation Format: Harry J. Gould, Kelly J. Sherman, Dennis Paul. Efficacy of targeted osmotic lysis using pulsed electric field stimulation compared to paclitaxel for treating murine, triple-negative breast carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1071.

Mn3O4-stabilized multiphase manganese oxides with micron cage structure for high-performance AZIBs

Aqueous zinc ion batteries (AZIBs) have become one of the most prospective energy storage devices due to their low cost, abundant resources, and hypotoxicity. However, AZIBs suffer from a bottleneck, that is, significant capacity fading during long cycle and bad performance at a high current density. In this work, we report a valuable cooperation strategy of multiphase Mn-based oxides (N-Mn3O4/MnO) via a two-step solvothermal method to obtain an attractive cathode for AZIBs. The high reversible specific capacity and superior rate capability of this cathode result from the facile charge transfer channel and ions (Zn2+/H+) insertion in the porous heterostructures featuring phase stability caused by the synergistic effects of N-doping, heterojunction and porous micron cage. Because the d-band centers of N-doped Mn3O4 are closer to the Fermi level, they are looked forward to overcoming the intrinsic activation barrier more effectively and promoting the reaction kinetics for electrochemical reactions. The N-Mn3O4/MnO cathode demonstrates a reversible specific capacity of 227.8 mAh g−1 over 1500 cycles at 5 A g−1. The capacity retention reaches up to 92.2% regarding the stable capacity of 247.2 mAh g−1 as the reference. The capacity retention rate of 77.2% and a loss of only 0.0091% per cycle are achieved at a high current density of 10 A g−1 for 2500 cycles. These results all prove the advantages of N-Mn3O4/MnO of the hybrid material. The meaning of this work is to put forward a compositional and structural design strategy for the Zn-Mn system for the cost-effective and high-performance rechargeable AZIBs. Besides, the application of a novel water-soluble binder (LA133) to AZIBs in this work is a solid step for the practical application of AZIBs.

Syndromes of Pseudo-Hyperaldosteronism.

Syndromes of Pseudo-Hyperaldosteronism.

Recurrent Neural Network Equalization for Wireline Communication Systems

Satisfying the demand for ever increasing data rates in wireline communication systems is challenging due to high frequency-dependent channel insertion loss causing significant inter-symbol interference (ISI). This motivates the use of ADC-based receiver architectures that allow for digital equalizer implementations. However, the large tap count feed-forward equalizers (FFEs) required at high data rates causes noise enhancement that can degrade signal-to-noise ratio (SNR) and high complexity is required to implement multi-tap decision feedback equalizers (DFEs). Moreover, analog front-end (AFE) nonlinearity can limit the performance of these traditional FFE-DFE architectures. This brief investigates an alternative approach with recurrent neural network (RNN) equalization based on long short-term memory (LSTM) and gate recurrent unit (GRU) cells. 64 Gb/s PAM4 modeling results show that the RNN topologies offer significant BER improvement over a wide SNR range for a channel with 30 dB loss at 16 GHz and enable operation over a channel with a large notch at 10 GHz that the traditional FFE-DFE topology cannot support. Synthesis results utilizing a 22 nm FinFET process yield only a 34% and 29% increase in receiver power consumption for the LSTM and GRU implementations, respectively, to enable this improved performance.

Transport mechanisms of SARS-CoV-E viroporin in calcium solutions: Lipid-dependent Anomalous Mole Fraction Effect and regulation of pore conductance

The envelope protein E of the SARS-CoV coronavirus is an archetype of viroporin. It is a small hydrophobic protein displaying ion channel activity that has proven highly relevant in virus-host interaction and virulence. Ion transport through E channel was shown to alter Ca2+ homeostasis in the cell and trigger inflammation processes. Here, we study transport properties of the E viroporin in mixed solutions of potassium and calcium chloride that contain a fixed total concentration (mole fraction experiments). The channel is reconstituted in planar membranes of different lipid compositions, including a lipid mixture that mimics the endoplasmic reticulum-Golgi intermediate compartment (ERGIC) membrane where the virus localizes within the cell. We find that the E ion conductance changes non-monotonically with the total ionic concentration displaying an Anomalous Mole Fraction Effect (AMFE) only when charged lipids are present in the membrane. We also observe that E channel insertion in ERGIC-mimic membranes – including lipid with intrinsic negative curvature – enhances ion permeation at physiological concentrations of pure CaCl2 or KCl solutions, with a preferential transport of Ca2+ in mixed KCl-CaCl2 solutions. Altogether, our findings demonstrate that the presence of calcium modulates the transport properties of the E channel by interacting preferentially with charged lipids through different mechanisms including direct Coulombic interactions and possibly inducing changes in membrane morphology.