Types Of Channels Research Articles

Rhythmic Contractions of Lymph Vessels and Lymph Flow Are Disrupted in Hypertensive Rats.

Hypertension increases the risk of lymphedema in patients with comorbidities, but whether hypertension directly compromises lymph vessel (LV) function and lymph flow is unclear. We compared the contractions of mesenteric LVs ex vivo and lymph flow in vivo between normotensive and Ang II (angiotensin II)-induced hypertensive rats and explored the ionic basis of contractile patterns. Key studies were recapitulated in spontaneously hypertensive rats and control Wistar-Kyoto rats. Video microscopy continuously recorded the diameters of cannulated rat mesenteric LVs, and high-speed optical imaging estimated mesenteric lymph flow in vivo. Jess capillary Western electrophoresis evaluated expression levels of ion channel proteins. Isolated LVs from Ang II-induced hypertensive rats exhibited dysrhythmic contractions, whereas LVs from both Ang II-induced hypertensive rats and spontaneously hypertensive rats exhibited reduced diastolic diameters and cross-sectional flow. Mesenteric lymph flow in vivo was 2.9-fold lower in Ang II-induced hypertensive rats compared with normotensive rats. Surprisingly, the LVs from Ang II-induced hypertensive rats expressed fewer intact L-type Ca2+ channel pore proteins and more modulatory cleaved C-terminal fragments. However, pharmacological block of voltage-gated K+ channels but not other K+ channel types in control LVs established the pattern of contractile dysfunction observed in hypertension. Jess capillary Western electrophoresis analysis confirmed a loss of Shaker-type KV1.2 channels in LVs from hypertensive rats. We provide initial evidence of lymphatic contractile dysfunction and compromised lymph flow in hypertensive rats, which may be caused by a loss of KV1.2 channels in the lymphatic muscle cells.

OFDM system based on parametric DFT transform

This study introduces a specific type of orthogonal frequency division multiplexing (OFDM) system that relies on the parametric discrete Fourier transform (DFT-alpha), where alpha is a parameter randomly selected within the range [-2pi, 0]. We investigate the performance of the proposed system across various channel types and modulation formats, including binary phase shift keying (BPSK), 16 quadratic amplitude modulation (QAM), analyzing aspects such as bit-error rate (BER), peak-to-average power ratio (PAPR), and computational complexity. This work considers the most interesting special case of the one-parameter DFT, which is the DFT-π/6 . The simulated results confirm the suggested OFDM system’s ability to minimize the computational complexity of the conventional OFDM system, standing as the primary contribution of the current study, while maintaining the performance identical. Therefore, the parametric DFT-OFDM system would be a good alternative to the classical DFT-OFDM. The findings suggest that parametric DFT based OFDM holds significant potential for high-speed optical wireless communication systems.

A Review on Network Covert Channel Construction and Attack Detection

ABSTRACTA covert network channel is a communication channel in which the message is secretly transmitted to the recipient. Sometimes, covert network channels are vulnerable to multiple attacks. Therefore, the message must be properly secure. In most cases, the covert channel is used to ensure data protection and allow users to freely access the Internet. In this paper, several recent studies are reviewed on covert network channels and examine the existing works from 2015 to 2024. This review article also discusses the undetectability and reliability of different types of covert network channels. Furthermore, a detailed description of the covert network channel's ability to hide in containers is provided. Existing research on covert network channels explains a few techniques for detecting attacks in secret data communication. However, several machine learning and deep learning techniques have been discussed in this article. Additionally, this article describes the accuracy of detection through an overview of current technologies. In addition, various countermeasures to prevent attacks in covert channels are also discussed in detail. However, in this case, the bandwidth limitations, data set limitations, and covert channel capacity are clearly defined, which will help future researchers build covert network channels and detect attacks. Finally, this work considers the challenges faced by covert network channels and the future scope of application.

Computational approaches for identifications of altered ion channels in keratoconus.

Keratoconus is an etiologically complex, degenerative corneal disease that eventually leads to loss of corneal integrity. Cells in corneal epithelium and endothelium express various types of ion channels that play important roles in ocular pathology. This emphasizes the need of understanding alterations of ion channels in keratoconus. Differential gene expression analysis was performed to identify deregulated ion channels in keratoconus patients using transcriptomic data. Thereafter correlation analysis of ion channel expression was performed to obtain the changed correlation between ion channels' expression in keratoconus patients versus control samples. Moreover, Protein-protein interaction networks and a pathway map was constructed to identify cellular processes altered due to the deregulation of ion channels. Furthermore, drugs interacting with deregulated ion channels were identified. Total 75 ion channels were found to be deregulated in keratoconus, of which 12 were upregulated and 63 were downregulated. Correlations between ion channel expressions found to be different in control and keratoconus samples. Thereafter, protein-protein interactions network was generated to identify hub ion channels in network. Furthermore, the pathway map was constructed to depict calcium signalling, MAPK signalling, synthesis and secretion of cortisol, and cAMP signalling. The 19 FDA- approved drugs that interact with the 6 deregulated ion channels were identified. Down-regulation of voltage-gated calcium channels can be attributed to reduced cell proliferation and differentiation. Additionally, deregulated ion channels in 3',5'- cyclic adenosine monophosphate signalling may be responsible for elevated cortisol level in progressive keratoconus patients.

On-Demand Delivery Platforms and Restaurant Sales

Restaurants are increasingly relying on on-demand delivery platforms (e.g., DoorDash, Grubhub, and Uber Eats) to reach customers and fulfill takeout orders. Although on-demand delivery is a valuable option for consumers, whether restaurants benefit from or are being hurt by partnering with these platforms remains unclear. This paper investigates whether and to what extent the platform delivery channel substitutes restaurants’ own takeout/dine-in channels and the net impact on restaurant revenue. Empirical analyses show that restaurants overall benefit from on-demand delivery platforms—these platforms increase restaurants’ total takeout sales while creating positive spillovers to customer dine-in visits. However, the platform effects are substantially heterogeneous, depending on the type of restaurants (independent versus chain) and the type of customer channels (takeout versus dine-in). The overall positive effect on fast-food chains is four times as large as that on independent restaurants. For takeout, delivery platforms substitute independent restaurants’ but complement chain restaurants’ own takeout sales. For dine-in, delivery platforms increase both independent and chain restaurants’ dine-in visits by a similar magnitude. Therefore, the value of delivery platforms to independent restaurants mostly comes from the increase in dine-in visits, whereas the value to chain restaurants primarily comes from the gain in takeout sales. Further, the platform delivery channel facilitates price competition and reduces the opportunity for independent restaurants to differentiate with premium services and dine-in experience, which may explain why independent restaurants do not benefit as much from on-demand delivery platforms. This paper was accepted by D. J. Wu, information systems. Funding: Z. Li is grateful to the National Science Foundation Division of Social and Economic Sciences for support provided through the CAREER award [Grant 2243736]. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2021.01010 .

ATP-gated P2x7 receptor is a major channel type at type II auditory nerves and required for hearing sensitivity efferent controlling and noise protection.

Hearing sensitivity and noise protection are mediated and determined by negative feedback of the cochlear efferent system. Type II auditory nerves (ANs) innervate outer hair cells (OHCs) in the cochlea and provide an input to this efferent control. However, little is known about underlying channel information. Here, we report that ATP-gated P2x7 receptor had a predominant expression at type II ANs and the synaptic areas under inner hair cells and OHCs with lateral and medial olivocochlear efferent nerves. Knockout (KO) of P2x7 increased hearing sensitivity with enhanced acoustic startle response (ASR), auditory brainstem response (ABR), and cochlear microphonics (CM) by increasing OHC electromotility, an active cochlear amplifier in mammals. P2x7 KO also increased susceptibility to noise. Middle level noise exposure could impair active cochlear mechanics resulting in permanent hearing loss in P2x7 KO mice. These data demonstrate that P2x7 receptors have a critical role in type II AN function and the cochlear efferent system to control hearing sensitivity; deficiency of P2x7 receptors can impair the cochlear efferent suppression leading to hearing oversensitivity and susceptibility to noise.

5G network performance using novel MIMO mixed FSO/MMW communication systems under pointing errors effect: test analysis using image transmission

Abstract Millimeter waves (MMW) enable high data rates over short distances; free-space optical (FSO) provides high-capacity optical wireless transmissions; and multiple-input multiple-output (MIMO) maximizes antenna utilization. These are the three leading technologies that work harmoniously to deliver 5G’s superior performance. This collaborative effort results in 5G’s ability to offer high connection capacities, low latency, and rapid speeds, creating new opportunities for industrial and internet of things applications. In this paper, the proposed system combines FSO links and MMW radio frequency (RF) links to enhance the performance of mixed FSO/RF systems. FSO experiences turbulence and pointing errors (PE), while MMW undergoes fading. Using both FSO and MMW provides diversity against channel fading. Furthermore, both the FSO and MMW links utilize MIMO technology to combat fading through spatial diversity. The FSO link is modeled with a Gamma-Gamma Turbulence model and PE. The MMW link is modeled with Rayleigh fading. By combining these two types of links with MIMO, the system can achieve improved performance compared to using either FSO or MMW alone. The dual nature of the system provides robustness against different types of channels fading effects. Overall, the goal is to enhance performance by capitalizing on the complementary channel characteristics of optical and RF links and exploiting MIMO’s spatial diversity benefits. In the present work, closed-form formulas accounting for the influence of PE are generated for the bit error rate (BER). This article also explores the MIMO mixed FSO/MMW system with multiple modulation techniques under various turbulence situations. The suggested system is ultimately verified by transmitting images with suitable fixed BER.

Distributary channel type and high‐quality reservoirs in tight sandstone—A case study on the outcrops and reservoirs of Xujiahe formation in Western Sichuan Basin

Distributary channel type and high‐quality reservoirs in tight sandstone—A case study on the outcrops and reservoirs of Xujiahe formation in Western Sichuan Basin

Pemetaan Banjir Kawasan Sungai Gadjah Putih dan Evaluasi Kinerja Saluran Drainase RW 14, Sumber, Banjarsari, Surakarta

Floods often occur due to river water overflowing to the surface. Flooding can also be caused by land development which increases surface runoff and impacts the drainage system. This can cause a decrease in the performance of the drainage channel. This research aims to map floods caused by runoff from the Gadjah Putih River, and the performance of existing drainage channels in RW 14 Sumber, Banjarsari, Surakarta. The rain data used is rain data from the Pabelan, Mojolaban, and Baki rain stations from 2000 to 2019. The Gumbel method is used to analyze rain return periods, runoff discharge analyzed by using Rational Method. Runoff discharge is explained at return periods of 2, 5, and 10 years, producing discharges of 8.15 m3/s respectively; 9.76 m3/day; and 10.61 m3/day. Floods are mapped using HEC-RAS by conducting steady flow analysis. The results of the flood mapping of the Gadjah Putih River showed that the area that experienced flooding at the return period of 2, 5 and 10 years respectively was 50,326.77 m2; 56,865.37 m2; 60,756.82 m2. Drainage performance analysis compares hydrology and hydraulic calculations. The analysis resulted drainage performance in RW 14 Sumber show that at the 2 year discharge period, 34 types of channels are safe, and 11 types of channels require repair; in the 5 year discharge period, 30 types of channels are safe, and 15 types of channels require repair; at the 10 year discharge period, 25 types of channels are safe, and 20 types of channels require repair.

Mathematical models of C-type and N-type inactivating heteromeric voltage gated potassium channels.

Voltage gated potassium channels can be composed of either four identical, or different, pore-forming protein subunits. While the voltage gated channels with identical subunits have been extensively studied both physiologically and mathematically, those with multiple subunit types, termed heteromeric channels, have not been. Here we construct, and explore the predictive outputs of, mechanistic models for heteromeric voltage gated potassium channels that possess either N-type or C-type inactivation kinetics. For both types of inactivation, we first build Markov models of four identical pore-forming inactivating subunits. Combining this with previous results regarding non-inactivating heteromeric channels, we are able to define models for heteromeric channels containing both non-inactivating and inactivating subunits of any ratio. We simulate each model through three unique voltage clamp protocols to identify steady state properties. In doing so, we generate predictions about the impact of adding additional inactivating subunits on a total channel's kinetics. We show that while N-type inactivating subunits appear to have a non-linear impact on the level of inactivation the channel experiences, the effect of C-type inactivating subunits is almost linear. Finally, to combat the computational issues of working with a large number of state variables we define model reductions for both types of heteromeric channels. For the N-type heteromers we derive a quasi-steady-state approximation and indicate where the approximation is appropriate. With the C-type heteromers we are able to write an explicit model reduction bringing models of greater than 10 dimensions down to 2.

Lubiprostone Improves Distal Segment-Specific Colonic Contractions through TRPC4 Activation Stimulated by EP3 Prostanoid Receptor

Background: Prokinetic agents are effective in increasing gastrointestinal (GI) contractility and alleviating constipation, often caused by slow intestinal motility. Lubiprostone (LUB), known for activating CLC-2 chloride channels, increases the chloride ion concentration in the GI tract, supporting water retention and stool movement. Despite its therapeutic efficacy, the exact mechanisms underlying its pharmacological action are poorly understood. Here, we investigated whether LUB activates the canonical transient receptor potential cation channel type 4 (TRPC4) through stimulation with E-type prostaglandin receptor (EP) type 3. Methods: Using isotonic tension recordings on mouse colon strips, we examined LUB-induced contractility in both proximal and distal colon segments. Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to determine mRNA levels of EP1-4 receptor subtypes in distal colonic muscular strips and isolated myocytes. The effects of a TRPC4 blocker and EP3 antagonist on LUB-stimulated contractions were also evaluated. Results: LUB showed significant contraction in the distal segment compared to the proximal segment. EP3 receptor mRNA levels were highly expressed in the distal colon tissue, which correlated with the observed enhanced contraction. Furthermore, LUB-induced spontaneous contractions in distal colon muscles were reduced by a TRPC4 blocker or EP3 antagonist, indicating that LUB-stimulated EP3 receptor activation may lead to TRPC4 activation and increased intracellular calcium in colonic smooth muscle. Conclusions: These findings suggest that LUB improves mass movement through indirect activation of the TRPC4 channel in the distal colon. The segment-specific action of prokinetic agents like LUB provides compelling evidence for a personalized approach to symptom management, supporting the defecation reflex.

Insights into Cheese Marketing in Bangladesh: Marketing Cost, Margin, and Efficiency

Cheese though not native to Bangladesh has seen an increased surge in popularity in recent years. Even though there have been several studies that focus on the economic aspects of cheese production, there is a dearth of studies tackling the marketing aspects of cheese in Bangladesh. This study is an attempt to examine the marketing channels, the cost associated, the marketing margin, and the marketing efficiency of cheese in Bangladesh. This study is mainly based on primary data, collected from purposively selected participants from the districts of Kishoreganj, Thakurgaon, and Manikganj. The respondents consisted of 50 cheese producers and 20 market intermediaries. Simple descriptive statistics were employed to analyze the data. Traditional and modern types of channels were associated with the marketing of cheese. Marketing cost analysis identified, transportation, facility rent, and outlet maintenance to be the primary cost components. The value additions of per kg cheese by wholesaler-cum-retailers, retailers, and supermarkets were calculated at BDT 232.40, BDT 97.12 and BDT 250, respectively. Significant net margins were observed across all the channels. Though producers mostly used Channel I, Channel III (Producers → Consumers) and Channel IV (Producers → Retailers → Consumers) were identified to be the most efficient among the different channels examined in the study. Channel II had the lowest price spread, on the contrary, Channel V had the highest one. Just after direct marketing, cheese producers received higher percentage of consumers price (74%) using Channel II. Given the current potential of the cheese industry, the government should focus on this sector to address and overcome existing challenges in cheese marketing.

Using the “Media as Mediator” Approach to Understand the Influence of Communication Channel Trust on COVID-19 Protective Behaviors: England, January 2022

In a secondary analysis, we examine how trust in pro-recommendation versus alternative communication channels mediated effects of demographic, personality, lifestyle, and political variables on COVID-19 protective behavior in England. In so doing, we adapt the media-as-mediator approach to the pandemic context. Respondents reported that family, close friends, primary care medical providers, and mainstream news media were relatively supportive of public health recommendations, and social media friend networks, faith/community groups, alternative news sites, and alternative health practitioners were relatively unsupportive. Parallel mediation analyses showed that effects of age, dutiful civic-mindedness, sensation-seeking, healthy lifestyle orientation, and more marginally, race on COVID-19 protective behavior were mediated by trust in these pro-recommendation and/or alternative communication channels. In some cases, trust in exemplars of both types of channels resulted in these channels influences largely canceling one another out.

Phase-cancellation of velocity oscillations in a flow duct using a slow-sound metamaterial

Self-sustained acoustic oscillations in industrial systems with mean flow can cause unwanted vibrations or noise pollution. Acoustic metamaterials can be engineered and integrated in such systems to prevent these limit cycles. In this study, an acoustic metamaterial is proposed for decreasing the acoustic admittance at the outlet of a contraction in a pipe. It can reduce velocity oscillations by more than 50%, without requiring an enlargement of the pipe or increasing the static resistance to the mean flow significantly. The acoustic metamaterial consists of an array of slow-sound and regular channels, which form a contraction in a pipe. The slow-sound effect shifts the resonances of the respective slow-sound channels. For the frequency of interest, the velocity oscillations of these two types of channels are out of phase, which reduces the spatially averaged velocity oscillations at the outlet of the contraction and therefore decreases its acoustic admittance. The effect is demonstrated experimentally, using impedance measurements and particle image velocimetry. A key achievement of this work is the demonstration of a device that is nearly lossless for the mean (steady) flow, i.e. having a low pressure drop, while being very stiff for the acoustic (oscillating) flow at its nominal working frequency, i.e. low admittance, which was so far a difficult challenge to address.

Olfactory cilia, regulation and control of olfaction.

The sense of smell is still considered a fuzzy sensation. Softly wafting aromas can stimulate the appetite and trigger memories; however, there are many unexplored aspects of its underlying mechanisms, and not all of these have been elucidated. Although the final sense of smell takes place in the brain, it is greatly affected during the preliminary stage, when odorants are converted into electrical signals. After signal conversion through ion channels in olfactory cilia, action potentials are generated through other types of ion channels located in the cell body. Spike trains through axons transmit this information as digital signals to the brain, however, before odorants are converted into digital electric signals, such as an action potential, modification of the transduction signal has already occurred. This review focuses on the early stages of olfactory signaling. Modification of signal transduction mechanisms and their effect on the human sense of smell through three characteristics (signal amplification, olfactory adaptation, and olfactory masking) produced by olfactory cilia, which is the site of signal transduction are being addressed in this review.

Mind the information gap: How sampling and clustering impact the predictability of reach‐scale channel types in California (USA)

AbstractClustering and machine learning‐based predictions are increasingly used for environmental data analysis and management. In fluvial geomorphology, examples include predicting channel types throughout a river network and segmenting river networks into a series of channel types, or groups of channel forms. However, when relevant information is unevenly distributed throughout a river network, the discrepancy between data‐rich and data‐poor locations creates an information gap. Combining clustering and predictions addresses this information gap, but challenges and limitations remain poorly documented. This is especially true when considering that predictions are often achieved with two approaches that are meaningfully different in terms of information processing: decision trees (e.g., RF: random forest) and deep learning (e.g., DNNs: deep neural networks). This presents challenges for downstream management decisions and when comparing clusters and predictions within or across study areas. To address this, we investigate the performance of RF and DNN with respect to the information gap between clustering data and prediction data. We use nine regional examples of clustering and predicting river channel types, stemming from a single clustering methodology applied in California, USA. Our results show that prediction performance decreases when the information gap between field‐measured data and geospatial predictors increases. Furthermore, RF outperforms DNN, and their difference in performance decreases when the information gap between field‐measured and geospatial data decreases. This suggests that mismatched scales between field‐derived channel types and geospatial predictors hinder sequential information processing in DNN. Finally, our results highlight a sampling trade‐off between uniformly capturing geomorphic variability and ensuring robust generalisation.

A novel advanced block assembly method with 3D printed channel systems

Modular construction offers economic and environmental advantages over conventional construction technologies. Although several researchers have introduced various modular construction systems, the methods for creating channel structures within block modules and injecting epoxy resin to connect blocks efficiently have not been fully explored. This study proposes a new assembly channel system for modular construction using 3D printing. Four different channel types are fabricated using 3D printing, and epoxy resin is injected for block connections. The relationships between channel geometries and structural resistance are thoroughly analyzed with the uniaxial tensile and three-point bending tests. Both experiments are also numerically simulated using the finite element method to validate the modeling methodology for assembly channel systems. The validated methodology is useful for evaluating assembly channel systems and enhancing the design of such systems. Overall, this study can foster the practical application of modularization across various industrial fields.

First copper (II) oxo-selenite-sulfate Cu4O(SeO3)(SO4)2 and the role of a lone electron pair in open framework crystal structure formation

New copper oxo-selenite-sulfate Cu4O(SeO3)(SO4)2 was prepared by the reaction of anhydrous CuSO4, CuO, and SeO2 in a sealed silica tube. The compound crystallizes in the triclinic P1‾ space group, with cell parameters a = 8.379(3)Å, b = 8.402(4) Å, c = 8.497(3) Å, α = 82.988(14) °, β = 61.006(9) °, γ = 62.105(14)°. The selenite-sulfate features open-framework crystal structure with two types of channels, where lone electron pairs of SeO32− groups are located. DFT calculations were made to support this statement and to investigate the nature of chemical bonding in the crystal structure and estimate the band gap (3.3 eV).The crystal structure of Cu4O(SeO3)(SO4)2 was compared to the related triclinic form of Cu4O(SeO3)3. The role of sulfate groups is also discussed.

Anchoring Catalytic Metal Nodes within a Single-Crystalline Pyrazolate Metal-Organic Framework for Efficient Heterogeneous Catalysis.

The synthesis of single-crystalline and robust pyrazolate metal-organic frameworks (Pz-MOFs) capable of facilitating challenging organic transformations is fundamentally significant in catalysis. Here we demonstrate a metal-node-based catalytic site anchoring strategy by synthesizing a single-crystalline and robust Pz-MOF (PCN-1004). PCN-1004 features one-dimensional (1D) copper-Pz chains interconnected by well-organized ligands, forming a porous three-dimensional (3D) network with two types of 1D open channels. Notably, PCN-1004 displays exceptional stability in aqueous solutions across a broad pH range (1 to 14), attributed to the robust copper-Pz coordination bonds. Significantly, PCN-1004 functions as an outstanding catalyst in cross dehydrogenative coupling reactions for constructing C-O/C-S bonds, even in the absence of directing groups, achieving yields of up to ~99%, with long cycle lives and high substrate compatibility. PCN-1004 outperforms all previously reported porphyrin-based homogeneous and heterogeneous catalysts. Control experiments and computations elucidate the pivotal catalytic role of the copper-Pz chains and reveal a free radical pathway for the reaction. This work not only demonstrates the successful implementation of a metal-node-based catalytic site anchoring strategy for the efficient catalysis of challenging organic transformations but also highlights the synergistic effect of a robust framework, 1D open channels, and active sites in enhancing catalytic efficiency within MOFs.

Anchoring Catalytic Metal Nodes within a Single‐Crystalline Pyrazolate Metal‐Organic Framework for Efficient Heterogeneous Catalysis

The synthesis of single‐crystalline and robust pyrazolate metal‐organic frameworks (Pz‐MOFs) capable of facilitating challenging organic transformations is fundamentally significant in catalysis. Here we demonstrate a metal‐node‐based catalytic site anchoring strategy by synthesizing a single‐crystalline and robust Pz‐MOF (PCN‐1004). PCN‐1004 features one‐dimensional (1D) copper‐Pz chains interconnected by well‐organized ligands, forming a porous three‐dimensional (3D) network with two types of 1D open channels. Notably, PCN‐1004 displays exceptional stability in aqueous solutions across a broad pH range (1 to 14), attributed to the robust copper‐Pz coordination bonds. Significantly, PCN‐1004 functions as an outstanding catalyst in cross dehydrogenative coupling reactions for constructing C‐O/C‐S bonds, even in the absence of directing groups, achieving yields of up to ~99%, with long cycle lives and high substrate compatibility. PCN‐1004 outperforms all previously reported porphyrin‐based homogeneous and heterogeneous catalysts. Control experiments and computations elucidate the pivotal catalytic role of the copper‐Pz chains and reveal a free radical pathway for the reaction. This work not only demonstrates the successful implementation of a metal‐node‐based catalytic site anchoring strategy for the efficient catalysis of challenging organic transformations but also highlights the synergistic effect of a robust framework, 1D open channels, and active sites in enhancing catalytic efficiency within MOFs.