Lateral Transmission Research Articles

Genetic algorithm-based shape optimization of rubber mount for tractor-cabin mounting system

Tractors are widely used for agricultural activities worldwide by farmers. The cabin mount of a tractor supports the weight of the cabin and isolates vibrations from the chassis. In this study, the cabin mount-shape parameters were optimized considering its design characteristics to reduce vibration and noise inside the cabin. Additionally, vibration and noise tests were conducted to evaluate the improvement in isolation performance owing to the optimization. The nonlinear material constants of the Mooney–Rivlin hyperelastic model were obtained through tensile tests on rubber materials. A finite element model of the cabin mount was developed, and an analysis model was constructed to derive the vertical and lateral stiffness and displacement transmissibility through static and dynamic analyses using the ABAQUS program. The shape parameters influencing vertical and lateral stiffness were determined, and an objective function to minimize displacement transmissibility was defined for optimization. The vertical and lateral displacement transmission rates of the mount were successfully decreased through the optimization. The noise and vibration test results indicate that the cabin noise decreased by approximately 1–2 dB, while vibrations in the frequency range below 100 Hz were reduced by more than 3 dB in all directions. The proposed technique can help engineers and manufacturers improve driver comfort and mitigate the adverse effects of excessive noise and vibrations on their mental and physical health.

Evaluation of different acoustic insulation methods in CLT structures

This study explores the efficacy of various structural noise insulation systems implemented in the construction of pilot houses made from Cross-Laminated Timber (CLT). Focusing on both vertical and lateral transmission, the research aims to evaluate the performance of different insulation methods in mitigating structural noise within these innovative wooden structures. The investigation involves a comprehensive testing regimen to assess the impact of insulation systems on noise reduction, considering both practical applications and theoretical considerations. The findings of this study contribute valuable insights into enhancing the acoustic performance of CLT pilot houses, thereby informing best practices for noise insulation in wooden construction systems.

The role of the extracellular matrix in the reduction of lateral force transmission in muscle bundles: A finite element analysis

Background and objectiveAging is associated with a reduction in muscle performance, but muscle weakness is characterized by a much greater loss of force loss compared to mass loss. The aim of this work is to assess the contribution of the extracellular matrix (ECM) to the lateral transmission of force in humans and the loss of transmitted force due to age-related modifications. MethodsFinite element models of muscle bundles are developed for young and elderly human subjects, by considering a few fibers connected through an ECM layer. Bundles of young and elderly subjects are assumed to differ in terms of ECM thickness, as observed experimentally. A three-element-based Hill model is adopted to describe the active behavior of muscle fibers, while the ECM is modeled assuming an isotropic hyperelastic neo-Hookean constitutive formulation. Numerical analyses are carried out by mimicking, at the scale of a bundle, two experimental protocols from the literature. ResultsWhen comparing numerical results obtained for bundles of young and elderly subjects, a greater reduction in the total transmitted force is observed in the latter. The loss of transmitted force is 22 % for the elderly subjects, while it is limited to 7.5 % for the young subjects. The result for the elderly subjects is in line with literature studies on animal models, showing a reduction in the range of 20–34 %. This can be explained by an alteration in the mechanism of lateral force transmission due to the lower shear stiffness of the ECM in elderly subjects, related to its higher thickness. ConclusionsComputational modeling allows to evaluate at the bundle level how the age-related increase of the ECM amount between fibers affects the lateral transmission of force. The results suggest that the observed increase in ECM thickness in aging alone can explain the reduction of the total transmitted force, due to the impaired lateral transmission of force of each fiber.

The Larynx is Protected from Secondary and Vertical Papillomavirus Infection in Immunocompetent Mice.

Mouse papillomavirus MmuPV1 causes both primary and secondary infections of the larynx in immunocompromised mice. Understanding lateral and vertical transmission of papillomavirus to the larynx would benefit patients with recurrent respiratory papillomatosis (RRP). To test the hypothesis that the larynx is uniquely vulnerable to papillomavirus infection, and to further develop a mouse model of RRP, we assessed whether immunocompetent mice were vulnerable to secondary or vertical laryngeal infection with MmuPV1. Larynges were collected from 405 immunocompetent adult mice that were infected with MmuPV1 in the oropharynx, oral cavity, or anus, and 31 mouse pups born to immunocompetent females infected in the cervicovaginal tract. Larynges were analyzed via polymerase chain reaction (PCR) of lavage fluid or whole tissues for viral DNA, histopathology, and/or in situ hybridization for MmuPV1 transcripts. Despite some positive laryngeal lavage PCR screens, all laryngeal tissue PCR and histopathology results were negative for MmuPV1 DNA, transcripts, and disease. There was no evidence for lateral spread of MmuPV1 to the larynges of immunocompetent mice that were infected in the oral cavity, oropharynx, or anus. Pups born to infected mothers were negative for laryngeal MmuPV1 infection from birth through weaning age. Secondary and vertical laryngeal MmuPV1 infections were not found in immunocompetent mice. Further work is necessary to explore immunologic control of laryngeal papillomavirus infection in a mouse model and to improve preclinical models of RRP. NA Laryngoscope, 134:2322-2330, 2024.

Re‑examining the mechanism of eccentric exercise‑induced skeletal muscle damage from the role of the third filament, titin (Review).

Intense and unaccustomed eccentric exercise has been extensively studied for its ability to induce muscle damage. However, the underlying mechanism of this phenomenon still requires further clarification. This knowledge gap arises from the need for explanation of the eccentric contraction through the sliding filament theory. The two-filament sarcomere model, which is consisted of thin and thick filaments, forms the basis of the sliding filament theory. The mechanisms of concentric and isometric contractions at the cellular and molecular levels are effectively described by this model. However, when relying solely on the cross-bridge swing, the sliding filament theory fails to account for specific observations, such as the stability of the descending limb of the force-length relationship curve. Recent evidence indicated that titin and the extracellular matrix (ECM) may play a protective role by interacting with the thick and thin filaments. During an eccentric contraction, titin serves as a third filament in the sarcomere, which helps regulate changes in passive force. The two-filament sarcomere model has limitations in explaining eccentric contraction, thus this compensates for those shortcomings. The present review explored the potential of replacing the two-filament sarcomere model with a three-filament sarcomere model, incorporating thin filaments, thick filaments and titin. This revised model offers a more comprehensive explanation of eccentric contraction phenomena. Furthermore, the sliding filament theory was investigated in the context of the three-filament sarcomere model. The double-layer protection mechanism, which involves increased titin stiffness and the ECM during eccentric contraction was explored. This mechanism may enhance lateral force transmission between muscle fibers and the ECM, resulting in sarcolemma and ECM shear deformation. These findings provided insight into the mechanism of eccentric exercise-induced skeletal muscle damage. Considering the three-filament sarcomere model and the double-layer protection mechanism, the present review offered a more logical and comprehensive understanding of the mechanism behind eccentric exercise-induced muscle damage.

Investigation on Lateral Vibration Transmission Control of a Shaft-hull System with a Piezoelectric Actuator Support

A piezoelectric actuator support (PAS) is proposed to suppress lateral vibration transmission from the shaft to the hull of underwater vehicles subjected to the excitation of propeller forces. The PAS consists of eight rhombic structures with embedded piezoelectric actuators and is arranged between the stern bearing housing and the hull. The dynamic model of the shaft-PAS-hull system is developed to analyze the characteristics of power flow through the PAS. The suppression performance of acoustic radiation of the hull is analyzed to verify the effectiveness of the PAS. Numerical results have shown that the PAS is able to suppress the transmission of lateral vibration induced by the propeller forces and accordingly reduce the hull vibration as well as sound radiation.

Influence of dimensional and connection characteristics of CLT building elements on predictive calculations

The ISO 12354-1 standard provides different calculation methods for evaluating lateral transmission depending on the vibroacoustic behavior of building structures; the standard classifies them into types A and B depending on whether the structural reverberation time of the considered element depends or not on the connecting elements. Although some construction elements are composed of the same material, they can belong to the first or second type, according to the technology of assembly or installation. CLT panels, generally belonging to type A, may sometimes behave as type B elements. This study deals with some of these cases through calculation examples based on experimental data collected on a real-scale building mockup.

Genetic modulation of CWD prion propagation in cervid PrP Drosophila.

Chronic wasting disease is a fatal prion condition of cervids such as deer, elk, moose and reindeer. Secretion and excretion of prion infectivity from North American cervids with this condition causes environmental contamination and subsequent efficient lateral transmission in free-ranging and farmed cervids. Variants of cervid PrP exist that affect host susceptibility to chronic wasting disease. Cervid breeding programmes aimed at increasing the frequency of PrP variants associated with resistance to chronic wasting disease may reduce the burden of this condition in animals and lower the risk of zoonotic disease. This strategy requires a relatively rapid and economically viable model system to characterise and support selection of prion disease-modifying cervid PrP variants. Here, we generated cervid PrP transgenic Drosophila to fulfil this purpose. We have generated Drosophila transgenic for S138 wild type cervid PrP, or the N138 variant associated with resistance to chronic wasting disease. We show that cervid PrP Drosophila accumulate bona fide prion infectivity after exposure to cervid prions. Furthermore, S138 and N138 PrP fly lines are susceptible to cervid prion isolates from either North America or Europe when assessed phenotypically by accelerated loss of locomotor ability or survival, or biochemically by accumulation of prion seeding activity. However, after exposure to European reindeer prions, N138 PrP Drosophila accumulated prion seeding activity with slower kinetics than the S138 fly line. These novel data show that prion susceptibility characteristics of cervid PrP variants are maintained when expressed in Drosophila, which highlights this novel invertebrate host in modelling chronic wasting disease.

Alignment, cross linking, and beyond: a collagen architect's guide to the skeletal muscle extracellular matrix.

The muscle extracellular matrix (ECM) forms a complex network of collagens, proteoglycans, and other proteins that produce a favorable environment for muscle regeneration, protect the sarcolemma from contraction-induced damage, and provide a pathway for the lateral transmission of contractile force. In each of these functions, the structure and organization of the muscle ECM play an important role. Many aspects of collagen architecture, including collagen alignment, cross linking, and packing density affect the regenerative capacity, passive mechanical properties, and contractile force transmission pathways of skeletal muscle. The balance between fortifying the muscle ECM and maintaining ECM turnover and compliance is highly dependent on the integrated organization, or architecture, of the muscle matrix, especially related to collagen. While muscle ECM remodeling patterns in response to exercise and disease are similar, in that collagen synthesis can increase in both cases, one outcome leads to a stronger muscle and the other leads to fibrosis. In this review, we provide a comprehensive analysis of the architectural features of each layer of muscle ECM: epimysium, perimysium, and endomysium. Further, we detail the importance of muscle ECM architecture to biomechanical function in the context of exercise or fibrosis, including disease, injury, and aging. We describe how collagen architecture is linked to active and passive muscle biomechanics and which architectural features are acutely dynamic and adapt over time. Future studies should investigate the significance of collagen architecture in muscle stiffness, ECM turnover, and lateral force transmission in the context of health and fibrosis.

Influence of Critical Zone Architecture and Snowpack on Streamflow Generation Processes: A Mountain‐Meadow Headwater System in a Mediterranean Climate

AbstractObservations from a granitic watershed within a Mediterranean climate reveal the hydrologic and critical zone functioning of a perennial stream headwater and its upslope contributing area within a meadow system in the Sierra Nevada, California. Chemical analysis (diagnostic tools of mixing models, end member mixing analysis, tritium, etc.) and physical data (stream stage, piezometers, soil water, snowpack, etc.) indicate there are two primary pathways of water input into a headwater stream sourced from a mountain meadow. One input is a shallower and younger subsurface pathway with water that resembles snowpack chemistry, and the other a deeper and older subsurface pathway with water that reflects the chemistry of the groundwater derived from the contributing hillslopes. Multi‐year observations reveal that regardless of snowpack amount, during the period of peak hillslope infiltration, shallow and deep pathways in the hillslope behave similarly to initiate headwater streams. However, during summer dry periods, similarities in active pathways within the meadow center are not maintained between high and low snowpack years. With less snow, perennial groundwater discharge within the meadow center is eliminated, becoming only a seasonal source at the meadow's outlet. At the meadow's edge, geophysically observed downslope thinning in saprolite thickness creates reduced lateral transmissivity and initiation points for headwater streams via enhanced groundwater discharge of upslope water. Combined, these findings suggest how loss of snowpack and critical zone structure can together mediate hydrologic function in a wet meadow system in a Mediterranean climate. Creating new understanding about the stability of hydraulic functioning in headwater wet‐meadow systems under a changing climate.

Buckling-Controlled Member for Improving the Ductile Behavior of Double-Layer Latticed Space Structures

In this paper, a new buckling-controlled member (BCM) is introduced for use in space structures. This member is composed of four components; namely: the encasing, joints, core, and adjustable nuts. The core is intended to act as a structural element to resist the axial loads by its yielding under compression loading. The steel encasing is supposed to confine the steel core. Adjustable steel nuts on the steel core act as lateral bracings and are responsible for lateral load transmission between the encasing and core. The joints at the two ends of the supports of the member. Six experimental tests have been performed under compression load to show the efficiency of the new member. The test results reveal that the proposed member can provide the needed ductility and can delay the brittle buckling of the members. Also, the BCM is capable of considering buckling modes and controlling the plastic range. The experimental and numerical results have also been compared. Additional numerical evaluations have been carried out using finite element models, in which the effects of different parameters of the member have been investigated. The obtained results showed that the arrangement of inner elements is the main factor affecting ductility and postponing the buckling of the members. In the end, the effects of the BCMs on the overall behavior of four double-layer space structures have been studied. The obtained results of analyses indicated that the BCMs can enhance the strength and ductility of space structures, thereby reducing the risk of collapse. Also, the seismic collapse of the space structure was postponed.

Emergence and History

Emergence and History

Coevolutionary analysis of the Philopteroides Mey, 2004 (Phthiraptera: Ischnocera) parasitizing bulbuls (Passeriformes: Pycnonotidae)

IntroductionAvian head lice comprise a diverse group of distantly related genera of lice that exhibit a strongly convergent morphology. Due to their lack of free-living stages, their strong morphological adaptations to living on the host’s head, and the limited opportunities for transfer between hosts during mating or nesting, the lateral transmission of head lice between non-conspecific hosts may be presumed to be restricted. Despite this, many species of head lice are ostensibly host generalists. We here examine lice of the head louse genus Philopteroides Mey, 2004, from bulbuls (Passeriformes: Pycnonotidae).MethodsWe use two different methods, ParaFit and Jane, to get insights on the co-evolutionary history of Philopteroides species and their bulbul hosts. Jane was run with a variation of event costs.ResultsOur phylogenetic analysis indicate that several morphologically cryptic species can be found in this group, most of which appear to be host specific. However, co-phylogenetic analyses indicate that host-switching has been common in the history of these lice, and co-speciation events have been rarer than expected. Moreover, lowest-cost co-evolutionary reconstructions under a variety of event costs are indistinguishable from random. An expanded dataset with more Philopterus-complex lice was found to be evenly balanced between host-switching and co-speciation events.DiscussionThe transfer of avian head lice between host species is poorly understood, but evidently fairly common. Several potential routes are discussed, but direct evidence is missing. Potentially, the presence of multiple bulbul species at fruiting trees may be an important factor in this transfer. However, such transfer routes also do not explain why Philopteroides lice on bulbuls appear to be distinct from those of other hosts. Moreover, as many of the species recovered in our analysis are morphologically indistinguishable, cryptic speciation appears to be common in this group.

The extracellular matrix of dystrophic mouse diaphragm accounts for the majority of its passive stiffness and is resistant to collagenase digestion

The healthy skeletal muscle extracellular matrix (ECM) has several functions including providing structural integrity to myofibers, enabling lateral force transmission, and contributing to overall passive mechanical properties. In diseases such as Duchenne Muscular dystrophy, there is accumulation of ECM materials, primarily collagen, which results in fibrosis. Previous studies have shown that fibrotic muscle is often stiffer than healthy muscle, in part due to the increased number and altered architecture of collagen fibers within the ECM. This would imply that the fibrotic matrix is stiffer than the healthy matrix. However, while previous studies have attempted to quantify the extracellular contribution to passive stiffness in muscle, the outcomes are dependent on the type of method used. Thus, the goals of this study were to compare the stiffness of healthy and fibrotic muscle ECM and to demonstrate the efficacy of two methods for quantifying extracellular-based stiffness in muscle, namely decellularization and collagenase digestion. These methods have been demonstrated to remove the muscle fibers or ablate collagen fiber integrity, respectively, while maintaining the contents of the extracellular matrix. Using these methods in conjunction with mechanical testing on wildtype and D2.mdx mice, we found that a majority of passive stiffness in the diaphragm is dependent on the ECM, and the D2.mdx diaphragm ECM is resistant to digestion by bacterial collagenase. We propose that this resistance is due to the increased collagen cross-links and collagen packing density in the ECM of the D2.mdx diaphragm. Taken altogether, while we did not find increased stiffness of the fibrotic ECM, we did observe that the D2.mdx diaphragm conveyed resistance against collagenase digestion. These findings demonstrate how different methods for measuring ECM-based stiffness each have their own limitations and can produce different results.

Opposing retrograde and astrocyte-dependent endocannabinoid signaling mechanisms regulate lateral habenula synaptic transmission

The lateral habenula (LHb) encodes aversive states, and its dysregulation is implicated in neuropsychiatric disorders, including depression. The endocannabinoid (eCB) system is a neuromodulatory signaling system that broadly serves to counteract the adverse effects of stress; however, CB1 receptor signaling within the LHb can paradoxically promote anxiogenic- and depressive-like effects. Current reports of synaptic actions of eCBs in the LHb are conflicting and lack systematic investigation of eCB regulation of excitatory and inhibitory transmission. Here, we report that eCBs differentially regulate glutamatergic and GABAergic transmission in the LHb, exhibiting canonical and circuit-specific inhibition of both systems and an opposing potentiation of synaptic glutamate release mediated via activation of CB1 receptors on astrocytes. Moreover, simultaneous depression of GABA and potentiation of glutamate release increases the net excitation-inhibition ratio onto LHb neurons, suggesting a potential cellular mechanism by which cannabinoids may promote LHb activity and subsequent anxious- and depressive-like aversive states.

Drug resistance analysis of three types of avian-origin carbapenem-resistant Enterobacteriaceae in Shandong Province, China

Animal-derived Enterobacteriaceae bacteria such as Escherichia coli (E. coli), Proteus mirabilis (P. mirabilis), and Klebsiella pneumoniae (K. pneumoniae) are important food-borne zoonotic bacilli that exist widely in the broiler-breeding industry. Although carbapenem antibiotics are considered to be the last line of defense against multidrug-resistant bacteria, carbapenem-resistant Enterobacteriaceae (CRE) break through them. In our study, we therefore, examined the prevalence of CRE and characteristics of antimicrobial resistance in 6 conventional broiler-fattening farms in Shandong Province, China. Our study revealed isolation rates of 3.57% (6/168) for carbapenem-resistant E. coli, 10% (5/50) for carbapenem-resistant P. mirabilis, and 3.03% (1/33) for carbapenem-resistant K. pneumoniae. All 12 CRE bacterial strains showed varying degrees of resistance to 27 antibiotics in 8 classes and were multidrug-resistant. The rate of the strains containing blaNDM genes, at 91.67% (11/12), was especially high. Among other results, the carrying rate of integrons in CRE bacteria was 91.67% (11/12), and 2 strains carried both class I and class II integrons, which accelerated the lateral transmission of resistant bacteria. Our first-ever finding of the 3 CRE bacteria E. coli, P. mirabilis, and K. pneumoniae on the same broiler farm suggests that poultry-derived CRE strains may pose a risk to humans. Moreover, our findings from surveillance can inform current understandings of the prevalence and characteristics of multidrug-resistant CRE in Shandong Province and, in turn, help to curb threats to food safety and public health and better prevent and control infectious zoonotic diseases.

Ocean-continent subduction cannot be initiated without preceding intra-oceanic subduction!

The formation of new subduction zones is a key element of plate tectonics and the Wilson cycle, and many different controlling mechanisms have been proposed to initiate subduction. Here, we provide a brief overview of the known scenarios of subduction initiation in intra-oceanic and ocean-continent tectonic settings. Intra-oceanic subduction is most commonly associated with mechanical heterogeneities within the oceanic lithosphere, such as pre-existing fracture zones, spreading ridges, and transform faults. Numerous and well-recognized examples of new active subduction zones formed in intra-oceanic environments during the Cenozoic, suggesting that the initiation of ocean-ocean subduction must be a routine process that occurs “easily and frequently” in the mode of plate tectonics currently operating on Earth. On the contrary, the most traditional mechanisms for the establishment of classic self-sustaining ocean-continent subduction—passive margin collapse and subduction transference—are surprisingly rare in observations and difficult to reproduce in numerical models. Two alternative scenarios—polarity reversal and lateral propagation-induced subduction initiation—are in contrast much better documented in nature and experimentally. However, switching of subduction polarity due to arc-continent collision and lateral transmission of subducting plate boundaries are both inextricably linked to pre-existing intra-oceanic convergence. We, therefore, conclude that the onset of classic ocean-continent subduction zones is possible only through the transition from a former intra-oceanic subduction system. This transition is likely facilitated by the ductile damage accumulation and stress concentration across the aging continental margin. From this perspective, the future closure of the Atlantic Ocean can be viewed as an archetypal example of the role of transitional process between intra-oceanic subduction (Lesser Antilles) and the development of a new subduction zone at a passive continental margin (eastern North America).

Lateral vibration analysis and active control of the propeller-shafting system using a scaled experimental model

The effective control of the transverse vibration is critical for the propeller-shaft coupling system, where excessive vibrations may cause reliability problems for working equipment and radiated noise of marine vessels. This paper is concerned with the active control method of reducing the lateral vibration transmission for the propeller-shafting system using a 1:10 scaled ratio experimental model. The lateral vibration characteristics of the propeller-shaft coupling system are investigated first by the experimental method, identifying the propeller mode and shafting modes that dominate the peak frequencies of system responses. The active vibration control system taking the electromagnetic actuator as the control power source and the raft vibration acceleration as the active control target is proposed for base-point control and cross-point control strategies. An adaptive feedforward controller based on the equivalent interference principle is developed by the improved LMS algorithm with parameter scale transformation. The designed adaptive algorithm accelerates the convergence rate of the controller parameters and tracks the unknown frequency fluctuations of the time-varying disturbance. Experimental implementation of the proposed active controller is carried out, demonstrating the applicability of the improved algorithm on the lateral vibration control of the propeller-shafting system.

Low-Cost Assessment Method for Existing Adjacent Beam Bridges

Damage in grouted joints is an unavoidable early disease in adjacent box beam bridges and hollow-core slab bridges. Joint damage will lead to degradation of the transverse load transmission capacity of the bridge, causing beams of the bridge superstructure to bear loads higher than the designed value, and eventually fail prematurely. Precise assessment of bearing--capacity degradation degree of adjacent box beam bridges and hollow-core slab bridges that are of great number is the keypoint to maintaining the serviceability of traffic network. The current specifications regard grouted joints as individual components and cannot correctly assess the degradation degree of bearing capacity caused by joint damage. In this paper, the traditional hinge connected beam method is improved by modifying deformation compatibility conditions at grouted joints. By using a modified hinge connected beam method, the relationship of joints at different locations with the lateral load distribution factor (LLDF) is analyzed. Based on analysis results, this paper proposes a new low-cost assessment method and a new assessment index that can utilize visual inspection results. Based on the concept of standard deviation, the proposed method assesses the degradation degree of the lateral load transmission performance of bridge superstructures by calculating the variation in LLDFs of beams, which is expressed by the lateral load distribution performance rating number LDN. The proposed method is applied to three real bridges. The accuracy of the calculation results is verified by comparing the ranking of LDNs of three bridges with the ranking of the variation degrees of lateral deflection influence lines of three bridges obtained from static-load test results.

Lateral impact noise I: Theory and application

Impact noise insulation has traditionally been thought of mostly in terms of vertical adjacencies. However, impact noise is transmitted in all directions though a building, and lateral and diagonally adjacent impact noise transmission can be significant. Lateral and diagonal impact transmission is a one-junction structural flanking path and is, therefore, amenable to statistical energy analysis-based calculation methods such as ISO 12354. In this paper, we review the relevant results from structural flanking path calculations and show how this provides a framework for understanding major features of lateral impact noise transmission such as the frequency dependence and effect of structure type. In turn, measurement of lateral impact noise provides a method of estimating the vibration reduction across junctions. These findings are illustrated with examples from field testing.