Classical Mode Research Articles

Reduced-order modelling based on non-linear modes

This paper addresses a detailed literature review on non-linear modes of vibration and its role in obtaining more efficient reduced-order models, as compared to those obtained by Galerkin's method using classical linear modes. Examples that emphasise the superior quality of the former models are supplied. Regarding the review on non-linear modes, a chronological development is presented, stressing the main stages of definitions, properties, methods for evaluation and application of non-linear modes to engineering problems, from Poincaré to Liapunov, from Rosenberg and Vakakis to Shaw and Pierre, from past to present.

Extracellular vesicles originating from autophagy mediate an antibody-resistant spread of classical swine fever virus in cell culture

ABSTRACT Free spread is a classical mode for mammalian virus transmission. However, the efficiency of this transmission approach is generally low as there are structural barriers or immunological surveillances in the extracellular environment under physiological conditions. In this study, we systematically analyzed the spreading of classical swine fever virus (CSFV) using multiple viral replication analysis in combination with antibody neutralization, transwell assay, and electron microscopy, and identified an extracellular vesicle (EV)-mediated spreading of CSFV in cell cultures. In this approach, intact CSFV virions are enclosed within EVs and transferred into uninfected cells with the movement of EVs, leading to an antibody-resistant infection of the virus. Using fractionation assays, immunostaining, and electron microscopy, we characterized the CSFV-containing EVs and demonstrated that the EVs originated from macroautophagy/autophagy. Taken together, our results showed a new spreading mechanism for CSFV and demonstrated that the EVs in CSFV spreading are closely related to autophagy. These findings shed light on the immune evasion mechanisms of CSFV transmission, as well as new functions of cellular vesicles in virus lifecycles. Abbreviations: 3-MA: 3-methyladenine; CCK-8: Cell Counting Kit-8; CSF: classical swine fever; CQ: chloroquine; CSFV: classical swine fever virus; DAPI, 4-,6-diamidino-2-phenylindole; EVs: extracellular vesicles; hpi: h post infection; IEM: immunoelectron microscopy; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MOI: multiplicity of infection; MVs: microvesicles; ND50: half neutralizing dose; PCR: polymerase chain reaction; PBS: phosphate-buffered saline; SEC: size-exclusion chromatography; siRNA: small interfering RNA; TEM: transmission electron microscopy.

The Role of Ferroptosis in Cardiovascular Disease and Its Therapeutic Significance.

Cardiovascular diseases (CVDs) are the leading cause of deaths worldwide with regulated cell death playing an important role in cardiac pathophysiology. However, the classical mode of cell death cannot fully explain the occurrence and development of heart disease. In recent years, much research has been performed on ferroptosis, a new type of cell death that causes cell damage and contributes to the development of atherosclerosis, myocardial infarction, heart failure, and other diseases. In this review, we discuss the role of different organelles in ferroptosis and also focus on the relationship between autophagy and ferroptosis. Additionally, we describe the specific mechanism by which ferroptosis contributes to the development of CVD. Finally, we summarize the current research on ferroptosis-related pathway inhibitors and the applications of clinically beneficial cardiovascular drugs.

Multi-Agent Unmanned Swarm Combat Architecture Based on Ooda Loop

The demand for the modern war against unmanned swarm is imminent, aiming at the new combat method of unmanned swarm, analyzing the operational structure of OODA loop is proposed. The design of unmanned swarm operation architecture will fully consider the operational requirements. Based on the classic operational mode OODA loop, the architecture design scheme is proposed from two parts: unmanned swarm combat planning based on OODA loop and unmanned swarm combat application. The functions of the architecture are divided and described in detail, and finally a multi-agent unmanned swarm operation architecture based on OODA loop is constructed. The design and planning of the operation architecture will contribute to the development of unmanned swarm operation.

Magnetoelastic instabilities in soft laminates with ferromagnetic hyperelastic phases

We investigate the microscopic and macroscopic instabilities developing in magnetoactive elastomer (MAE) composites undergoing large deformations in the presence of an external magnetic field. In particular, we consider the MAEs with bi-phasic layered microstructure, with phases exhibiting ferromagnetic behavior. We derive an explicit expression for the magnetic field-induced deformation of MAEs with hyperelastic phases. To perform the magnetoelastic instability analysis, we employ the small-amplitude perturbations superimposed on finite deformations in the presence of the magnetic field. We examine the interplay between the macroscopic and microscopic instabilities. We find that the layered MAEs can develop microscopic instability with antisymmetric buckling modes, in addition to the classical symmetric mode. Notably, the antisymmetric microscopic instability mode does not appear in a purely mechanical scenario (when a magnetic field is absent). Furthermore, our analysis reveals that the wavelength of buckling patterns is highly tunable by the applied magnetic field, and by the properties and volume fractions of the phases. Our findings provide the information for designing materials with reconfigurable microstructures. This material ability can be used to actively tune the behavior of materials by a remotely applied magnetic field. The results can be utilized in designing tunable acoustic metamaterials, soft actuators, sensors, and shape morphing devices.

Pose-varied swing arm profilometer test for off-axis aspheric surfaces with strong asphericity.

The swing arm profilometer (SAP) has been widely used to test large aspheric optics by measuring the asphericity from its best-fitting sphere (BFS). To further improve the test accuracy, we propose a pose-varied test mode for the SAP with a shorter-range probe to measure off-axis aspheric surfaces with stronger asphericity. In contrast to the classical SAP mode in which the air-table is fixed in a stationary position during measurement, we adjust the pose of each scan arc to match the local BFS and the measurement range of the probe decreases to half that of the global asphericity. To verify the effectiveness, we conduct experiments on an off-axis asphere with a diameter of 3 and 2 m. Compared with a classical SAP mode, it achieved an improved performance of 50% higher repeatability and 32% higher accuracy.

Wind-resistant structural optimization of supertall buildings based on high-frequency force balance wind tunnel experiment

The high-frequency force balance (HFFB) wind tunnel test is one of the most widely used techniques to estimate wind effects on supertall buildings. This paper introduces a wind-resistant optimal design method of supertall buildings based on HFFB wind tunnel experiments. Based on the HFFB wind tunnel test and wind-induced vibration analysis, it provides a reliable and efficient method for structural optimization of supertall buildings with different types of structural members and multiple constraints. Taking advantage of the classic linear mode shape assumption of the HFFB technique, this paper also presents an alternative routine that transforms all different types of constraints into a uniform frequency constraint, which significantly reduces the computational intensity while still offers acceptable accuracy of optimization results. Moreover, the sensitivity of the optimization results to the adopted basic wind pressure value is discussed. The total material cost of the optimized structure increases exponentially with the increase of the basic wind pressure, indicating that the structural costs of supertall buildings are quite sensitive to the adopted basic wind pressure for structural design and its value should be precisely determined by the wind climate analysis of the construction site.

Investigating Wi-Fi, Bluetooth, and Bluetooth Low-Energy Signal Characteristics for Integration in Vehicle–Pedestrian Collision Warning Systems

The purpose of the study is to investigate the comparative field performance of Wi-Fi, Bluetooth Classic (Bluetooth) and Bluetooth Low Energy (BLE) signal modes for integration in vehicle–pedestrian collision warning systems. The study compares these wireless signal modes to find out which one is most appropriate to be utilized in these systems and provides better results in terms of accuracy and functionality. Five factors including received signal strength indicator (RSSI)-distance relationship, rainfall effects on the signals, motion effects, non-line of sight effects and signal transmission rates were selected for evaluation. These factors were selected considering the requirements of vehicle–pedestrian collision warning systems and compared with each other based on experimental outcomes. The results of the experiments indicated the overall superiority of BLE mode over Wi-Fi and Bluetooth modes to be utilized in these systems. Application of this mode may provide the possibility of fast collision warnings thanks to low signal transmission intervals and high probability of simultaneous signal detections by multiple signals scanners. Moreover, the capability of this mode to accurately estimate distance and position is higher than Wi-Fi mode and not significantly different from Bluetooth mode.

Mirror and Circular Symmetry of Autofocusing Beams

This article demonstrates the crucial importance of the symmetrization method for the formation of autofocusing beams. It is possible to impart autofocusing properties to rather arbitrary distributions, for example, truncated and inverted classical modes (such as Hermite–Gaussian, Laguerre–Gaussian, and Bessel modes) or shift the fundamental Gaussian beam by inserting mirror or circular symmetry. The most convenient for controlling autofocusing characteristics is the truncated sinus function with a power-law argument dependence. In this case, superlinear chirp beams (with power q > 2) exhibit sudden and more abrupt autofocusing than sublinear chirp beams (with power 1 < q < 2). Comparison of the different beams’ propagation is performed using fractional Fourier transform, which allows obtaining the field distribution in any paraxial region (both in the Fresnel and Fraunhofer diffraction regions). The obtained results expand the capabilities of structured beams in various applications in optics and photonics.

Frank-van der Merwe growth in bilayer graphene

Frank-van der Merwe growth in bilayer graphene

Controlled Anchoring of (Phenylureido)sulfonamide-Based Receptor Moieties: An Impact of Binding Site Multiplication on Complexation Properties.

The repetition of urea-based binding units within the receptor structure does not only lead to monomer properties multiplication. As confirmed by spectroscopic studies, UV-Vis and 1H-NMR in classical or competitive titration mode, the attachment to a carrier allocates the active moieties to mutual positions predetermining the function of the whole receptor molecule. Bivalent receptors form self-aggregates. Dendritic receptors with low dihydrogen phosphate loadings offer a cooperative complexation mode associated with a positive dendritic effect. In higher dihydrogen phosphate concentrations, the dendritic branches act independently and the binding mode changes to 1:1 anion: complexation site. Despite the anchoring, the dendritic receptors retain the superior efficiency and selectivity of a monomer, paving the way to recyclable receptors, desirable for economic and ecological reasons.

Dynamic Processes in a Superconducting Adiabatic Neuron with Non-Shunted Josephson Contacts

We investigated the dynamic processes in a superconducting neuron based on Josephson contacts without resistive shunting (SC-neuron). Such a cell is a key element of perceptron-type neural networks that operate in both classical and quantum modes. The analysis of the obtained results allowed us to find the mode when the transfer characteristic of the element implements the “sigmoid” activation function. The numerical approach to the analysis of the equations of motion and the Monte Carlo method revealed the influence of inertia (capacitances), dissipation, and temperature on the dynamic characteristics of the neuron.

Radius ratio dependency of the instability of fully compressible convection in rapidly rotating spherical shells

Based on the fully compressible Navier–Stokes equations, the linear stability of thermal convection in rapidly rotating spherical shells of various radius ratios $\eta$ is studied for a wide range of Taylor number $Ta$, Prandtl number $Pr$ and the number of density scale height $N_\rho$. Besides the classical inertial mode and columnar mode, which are widely studied by the Boussinesq approximation and anelastic approximation, the quasi-geostrophic compressible mode is also identified in a wide range of $N_\rho$ and $Pr$ for all $\eta$ considered, and this mode mainly occurs in the convection with relatively small $Pr$ and large $N_\rho$. The instability processes are classified into five categories. In general, for the specified wavenumber $m$, the parameter space ($Pr, N_\rho$) of the fifth category, in which the base state loses stability via the quasi-geostrophic compressible mode and remains unstable, shrinks as $\eta$ increases. The asymptotic scaling behaviours of the critical Rayleigh numbers $Ra_c$ and corresponding wavenumbers $m_c$ to $Ta$ are found at different $\eta$ for the same instability mode. As $\eta$ increases, the flow stability is strengthened. Furthermore, the linearized perturbation equations and Reynolds–Orr equation are employed to quantitatively analyse the mechanical mechanisms and flow instability mechanisms of different modes. In the quasi-geostrophic compressible mode, the time-derivative term of disturbance density in the continuity equation and the diffusion term of disturbance temperature in the energy equation are found to be critical, while in the columnar and inertial modes, they can generally be ignored. Because the time-derivative term of the disturbance density in the continuity equation cannot be ignored, the anelastic approximation fails to capture the instability mode in the small-$Pr$ and large-$N_\rho$ system, where convection onset is dominated by the quasi-geostrophic compressible mode. However, all the modes are primarily governed by the balance between the Coriolis force and the pressure gradient, based on the momentum equation. Physically, the most important difference between the quasi-geostrophic compressible mode and the columnar mode is the role played by the disturbance pressure. The disturbance pressure performs negative work for the former mode, which appears to stabilize the flow, while it destabilizes the flow for the latter mode. As $\eta$ increases, in the former mode the relative work performed by the disturbance pressure increases and in the latter mode decreases.

Triggering flow of jammed cohesive granular materials using modulated pulsed airflow

AbstractRealizing the stable high‐flux flow of cohesive granular materials is a complicated subject. We experimentally studied the dynamic characteristics of cohesive granular materials discharged from hopper under modulated pulsed airflow. Results show that pulsed airflow with a smaller duty cycle can effectively trigger the stable flow of jammed cohesive granular materials. Furthermore, under proper working conditions, the hopper flow will change from the classic arch breaking mode to a free flowing mode like liquid. The flow rate of the powder in the free flowing mode will decrease as powder bed height decreases, which overturns the consistent recognition. The oscillating shear provided by the pulsed airflow eliminates the Janssen effect and achieves a liquid‐like stress transmission, which supports the above findings. Through energy analysis, we gave the scaling relationship between the pressure gradient and the pulse parameters to cover the experimental data and revealed the internal mechanism.

Inositol serves as a natural inhibitor of mitochondrial fission by directly targeting AMPK

Mitochondrial dynamics regulated by mitochondrial fusion and fission maintain mitochondrial functions, whose alterations underline various human diseases. Here, we show that inositol is a critical metabolite directly restricting AMPK-dependent mitochondrial fission independently of its classical mode as a precursor for phosphoinositide generation. Inositol decline by IMPA1/2 deficiency elicits AMPK activation and mitochondrial fission without affecting ATP level, whereas inositol accumulation prevents AMPK-dependent mitochondrial fission. Metabolic stress or mitochondrial damage causes inositol decline in cells and mice to elicit AMPK-dependent mitochondrial fission. Inositol directly binds to AMPKγ and competes with AMP for AMPKγ binding, leading to restriction of AMPK activation and mitochondrial fission. Our study suggests that the AMP/inositol ratio is a critical determinant for AMPK activation and establishes a model in which AMPK activation requires inositol decline to release AMPKγ for AMP binding. Hence, AMPK is an inositol sensor, whose inactivation by inositol serves as a mechanism to restrict mitochondrial fission.

Functionalized Tumor‐Targeting Nanosheets Exhibiting Fe(II) Overloading and GSH Consumption for Ferroptosis Activation in Liver Tumor

Liver tumor is difficult to cure for its high degree of malignancy and rapid progression characteristics. Ferroptosis as a new model of inducing cell death is expected to break the treatment bottleneck of liver tumors. Here, a strategy to induce ferroptosis in HepG2 cells with acid-degradable tumor targeted nanosheets Cu-Hemin-PEG-Lactose acid (Cu-Hemin-PEG-LA) is proposed. After highly ingested by HepG2 cells, Cu-Hemin-PEG-LA nanosheets are degraded by weak acid and release Cu(II) and hemin, which consuming intracellular glutathione (GSH) content and increasing the expression of heme oxygenase 1 (HMOX1) protein, respectively. Furthermore, the expression of glutathione peroxidase 4 protein (GPX4) is down-regulated by consumption intracellular GSH content via converting GSH into glutathione oxidized (GSSG), which is named the classical mode. The intracellular Fe2+ content is overloaded by the significant up-regulation of HMOX1 expression, which is denoted as nonclassical mode. The synergistic effect of classical and nonclassical mode increased the intracellular lipid reactive oxide species, induced the occurrence of ferroptosis and up-regulated the expression of BH3 interacting domain death agonist (BID), apoptosis-inducing factor (AIF), and endonuclease G proteins (EndoG). The synergistic strategy demonstrate the excellent ferroptosis induction ability and antitumor efficacy in vivo, which provides great potential for the clinical transformation of ferroptosis.

Diets of erythritol, xylitol, and sucrose affect the digestive activity and gut bacterial community in adult house flies

AbstractPolyol sweeteners, including erythritol and xylitol, have been investigated for their potential in insect control against a number of pests including mosquitoes, fruit flies, ants, and filth flies. Several insecticidal modes of action for the polyols have been proposed in non‐biting flies and include: (1) dehydration from excessive regurgitation, (2) arrestment of physiological processes due to abnormally high hemolymph osmolality or osmotic diarrhea, and (3) alteration of the gut microbiome. Here, we explored the proposed modes of action in the house fly, Musca domestica L. (Diptera: Muscidae), a non‐biting fly of medical and veterinary importance. House flies fed erythritol or xylitol regurgitated at a significantly higher rate when compared to flies that ingested sucrose. Flies that ingested sucrose solutions had higher hemolymph osmolality than erythritol but not xylitol, and deposited significantly more fecal spots than flies fed polyol solutions. Cultivable bacteria were least abundant in flies fed solutions of either sucrose or xylitol and most abundant in control flies provided water only. Of the potential modes of action tested, physiological stress from excessive post‐feeding regurgitation seems the likeliest cause of death related to polyol consumption. However, we cannot rule out a classical toxicological or biochemical mode of action from these results. Although the efficacy of polyols as active ingredients is still under debate, their use as other components in fly control products may be beneficial. Due to widespread resistance to a limited number of insecticidal chemicals registered for house fly control, it is important that new control chemicals be thoroughly assessed for usefulness.

المعتقدات السودانية في الشعر السوداني

In any community, beliefs are formed according to ideological, historical, political, intellectual, social and environmental changes. Hence, the research aims at unmasking the role of these changes in forming beliefs in the Sudan and, thereof, showing the way they are reflected in Sudanese poetry. Accordingly, the problem of the research consists inherently in the following question: to what extent could the Sudanese poets highlight Suda- nese beliefs in their own poetry? In this context, a group of Sudanese poets have highlighted the images of those Sudanese beliefs which are distinguished from the beliefs of other countries. In this regard, the Sudanese poets are obviously strongly affected by the call of the late Sudanese critic, Hamza al-Malik Ṭambal (in early twentieth century), in which he called on the Sudanese poets to emancipate themselves from imitating the classic mode of old and contemporary Arab poetry. To Ṭambal, this style of the classic Arab verse has negatively impacted the Sudanese poem, the result of which is the lack of the distinctive character of the Sudanese poetry. Of the most important outcomes concluded by the researcher is that the Sudanese poets, in their portrayal of the Sudanese beliefs in their poetries, have been flagrantly been affected by the call of the Sudanese critic, Ṭambal. Therefore, the Sufi idiosyncrasy has predominantly prevailed over these images as a result of the overriding Sufi current over the Sudanese community. Likewise, before penetration of Islam into the Sudan, the indigenous Sudanese beliefs had had a clear role in forming those images, notwithstanding the incompatibility of the images to the Islamic faith. Moreover, the Sudanese social variation had its own obvious role in forming the images of those beliefs, particularly predilection for rapture and music rhythm. Also, of the ensuing outcomes, those icons came to be as closely resembling folkloric pictures

Toughening induced by the formation of facets in mode I+III brittle fracture: Experiments versus a two-scale Cohesive Zone model

When subjected to some anti-plane shear mode III loading, segmentation of the crack front frequently occurs during propagation: even if the crack is initially planar, propagation produces facets/segments rotated toward the shear free direction. Here, we examine, both experimentally and theoretically, the effect of this microstructure on the effective macroscale brittle fracture toughness. Experiments performed on PMMA beams reveal that the critical load leading to abrupt rupture increases with mode III to mode I ratio. This apparent macroscopic toughening is usually taken into account by invoking a specific mode III toughness in addition to the mode I one. By applying thoroughfully a micro/macroscale Cohesive Zone (CZ) model that we have recently developed, we demonstrate that an additional material constant is useless here since this toughness increase can be attributed mainly to the presence of the facets at the microscale, whose geometry can be anticipated to depend on the classical mode I material constants. More precisely, two related physical mechanisms are generated due to the formation of a disconnected crack front: (i) changes in fractured surface area in comparison to a straight propagation, and (ii) crack shielding caused by the facets that reduce the effective crack opening. While the first effect is obvious to quantify, we show that the second plays an essential role but is more complex to take into account: it depends on the solution of the three-dimensional elasticity problem in presence of the facets, that is considered in the CZ model. We illustrate on the experiments how to use this approach in practice to determine the critical fracture threshold.

A role for substance P and acid-sensing ion channel 1a in prolotherapy with dextrose-mediated analgesia in a mouse model of chronic muscle pain.

Prolotherapy is widely used in pain control and tissue repair in pain medicine. The classical mode is injection with hypertonic dextrose in muscle or perimysium. However, the analgesic mechanism is still not known. Here, we successfully established dextrose-mediated antinociception in a mouse model of fibromyalgia. The antinociceptive effects of dextrose injections were evaluated in a mouse model of fibromyalgia, in which bilateral chronic mechanical hyperalgesia was induced by unilateral intramuscular acid injection. The injectant (dextrose), dose (≥5%), and volume (>10 μL), but not osmolarity, were essential for the prolotherapy. Further studies showed that the activation of acid-sensing ion channel 1a (ASIC1a), neural activation, and the release of substance P from muscle afferents were required in the dextrose-induced reduction of mechanical hypersensitivity. Both pharmacological blockade and genetic deletion of ASIC1a or substance P as well as lidocaine abolished the dextrose-induced antinociception in mice with chronic hyperalgesia. Moreover, intramuscular dextrose injection induced phosphorylated extracellular signal-regulated kinase expression in dorsal root ganglion neurons expressing substance P; the phosphorylated extracellular signal-regulated kinase expression was inhibited by the ASIC1a antagonist PcTx1. The optimal settings for prolotherapy in fibromyalgia-like pain are dextrose dependent and volume dependent, and the peripheral antinociception involves ASIC1a and substance P signaling in muscle afferents. This study suggests a possible mechanism of action of dextrose prolotherapy in noninflammatory muscle pain such as fibromyalgia and provides insights into treating other types of chronic pain.