Wall Structure Research Articles

Value of comprehensive evaluation of bladder structure and function in children by multi-modal ultrasound

To comprehensively evaluate the structure and function of the bladder wall in children using multi-modal ultrasound (MMU). A total of 110 children without urinary symptoms admitted to the First Affiliated Hospital of Zhengzhou University from January 2022 to June 2023 were included prospectively. MMU was performed and the vesical volume (VV), bladder wall thickness (BWT), shear wave velocity (SWV) of the anterior wall, resistance index (RI) and vascularization index (VI) were measured in the filled and emptied bladder respectively, and the ultrasound bladder compliance (UBC) was also calculated. The differences in MMU parameters in children among different bladder states, age groups and sexes and the correlation between age and different MMU parameters were analyzed. The age of 110 children was (6.4±3.5) years, of which 60 were boys (54.5%). The VV [127.00 (79.00, 219.50) vs 6.65 (5.10, 9.60) ml, P<0.001] and SWV [(2.25±0.36) vs (1.54±0.20) m/s, P<0.001] of filling condition were higher than that of emptying condition, while BWT [(2.52±0.25) vs (6.72±0.74) mm, P<0.001] and VI [(4.36±0.52)% vs (8.15±1.75) %, P<0.001] were lower than that of emptying condition. There were no significant differences in VV, BWT, SWV, RI, VI and UBC between boys and girls under either bladder emptying or filling conditions (all P>0.05). BWT in emptying condition, VV and BWT in filling condition all increased with age (r was 0.706, 0.891 and 0.298, respectively, and all P<0.05). MMU in children contributes to the comprehensive evaluation of bladder wall, and the influence of age and bladder filling state should be considered when evaluating MMU parameters.

Dynamic Analysis of Submarine-Buried Pipelines Considering Fluid–Structure Interaction

Buried pipes are widely used for submarine water transportation, but the complex operating conditions in the seabed pose challenges for the modeling of buried pipes. In order to more accurately capture the dynamic behavior of the buried pipes in the seabed, in this study, considering the pipeline and soil as a systematic structure is proposed, improving the fluid–structure interaction four-equation model to make it applicable for the calculation of buried pipe system modes. After verifying the practicality of the model, considering the external seawater as uniform pressure, the coupling at the joints, and the Poisson coupling of submarine pipelines during transient processes are discussed, revealing that structural vibrations under both forms of coupling will cause greater hydraulic oscillations. The impact of soil elastic modulus on the system’s response is further discussed, revealing that increasing the modulus from 0 to 1015 Pa raises the wave speed from 498 m/s to 1483 m/s, causing a 40% increase in the amplitude of pressure oscillations. Finally, the vibration modes of the combined structure of pipe wall and soil are discussed, revealing that the vibration modes are mainly dominated by water hammer pressure, with the superposition of pipeline stress waves and soil stress waves. In this study, the dynamic behavior of submarine pipelines is elucidated, providing a robust foundation for regulating and mitigating fatigue failures in such systems.

Recent Advances in Direct Synthesis of Functional Polymers of Intrinsic Microporosity Based on (Super)Acid Catalysis.

Polymers of intrinsic microporosity (PIMs) are an emerging class of amorphous organic porous materials with solution processability, which are widely used in a multitude of fields such as gas separation, ion conduction, nanofiltration, etc. PIMs have adjustable pore structure and functional pore wall, so it can achieve selective sieving for specific substances. In order to meet the functional requirements of PIMs, two principal methods are used to synthesize functional PIMs, namely, post-modification of PIMs precursors and functionalization of monomers. A number of post-modification routes have been reported, however, the direct synthesis of functional PIMs with diverse groups still remains a challenge. The synthesis of PIMs through the acid-catalyzed polyhydroxyalkylation has been demonstrated to be an effective solution, exhibiting the advantages of wider substrates range, milder reaction conditions, and higher molecular weight. Recently, a series of functional substrates for direct synthesis of PIMs have been proposed. This article presents a review and summary of recent advances in synthesizing PIMs via acid-catalyzed polyhydroxyalkylation, and the synthesis route and structure-activity relationship are emphasized, which provides a versatile platform for the direct synthesis of functional PIMs.

Engineering of CmpLs enhances L-glutamate production of Corynebacterium glutamicum

The efficient production of L-glutamate is dependent on the product's rapid efflux, hence researchers have recently concentrated on artificially modifying its transport system and cell membrane wall structure. Considering the unique composition and structure of the cell wall of Corynebacterium glutamicum, we investigated the effects of CmpLs on L-glutamate synthesis and transport in SCgGC7, a constitutive L-glutamate efflux strain. First, the knockout strains of CmpLs were constructed, and it was confirmed that the deletion of CmpL1 and CmpL4 significantly improved the performance of L-glutamate producers. Next, temperature-sensitive L-glutamate fermentation with the CmpL1 and CmpL4 knockout strains were carried out in 5 L bioreactors, where the knockout strains showcased temperature-sensitive characteristics and enhanced capacities for L-glutamate production under high temperatures. Notably, the CmpL1 knockout strain outperformed the control strain in terms of L-glutamate production, showing production and yield increases of 69.2% and 55.3%, respectively. Finally, the intracellular and extracellular metabolites collected at the end of the fermentation process were analyzed. The modification of CmpLs greatly improved the L-glutamate excretion and metabolic flux for both L-glutamate production and transport. Additionally, the CmpL1 knockout strain showed decreased accumulation of downstream metabolites of L-glutamate and intermediate metabolites of tricarboxylic acid (TCA) cycle, which were consistent with its high L-glutamate biosynthesis capacity. In addition to offering an ideal target for improving the stability and performance of the industrial strains for L-glutamate production, the functional complementarity and redundancy of CmpLs provide a novel target and method for improving the transport of other metabolites by modification of the cell membrane and cell wall structures in C. glutamicum.

Elucidating assembly and function of VirB8 cell wall subunits refines the DNA translocation model in Gram-positive T4SSs.

Bacterial type IV secretion systems (T4SSs) are widespread nanomachines specialized in the transport across the cell envelope of various types of molecules including mobile genetic elements during conjugation. Despite their prevalence in Gram-positive bacteria, including relevant pathogens, their assembly and functioning remain unknown. This study addresses these gaps by investigating VirB8 proteins, known to be central components of conjugative T4SSs in Gram-positive bacteria. However, the functional packing and precise role of VirB8 in T4SSs biology remain undefined. Our findings elucidate the nature of VirB8 proteins as cell wall components, where they multimerize and exhibit a conserved assembly pattern, distinct from VirB8 in Gram-negative bacteria. We also demonstrate that VirB8 proteins interact with other T4SS subunits and DNA, indicating their pivotal role in the building of the DNA translocation channel across the cell wall. We lastly propose a distinct architecture for conjugative T4SSs in Gram-positive bacteria compared to their Gram-negative counterparts, possibly attributed to the differences in the cell wall structure.

Single-cell sequencing of human Langerhans cells identifies altered gene expression profiles in patients with atopic dermatitis.

Atopic dermatitis (AD) is characterized by dysregulated T cell immunity and skin microbiome dysbiosis with predominance of Staphylococcus aureus, which is associated with exacerbating AD skin inflammation. Specific glycosylation patterns of S. aureus cell wall structures amplify skin inflammation through interaction with Langerhans cells (LCs). Nevertheless, the role of LCs in AD remains poorly characterized. Here, we performed single cell RNA sequencing of primary epidermal LCs and dermal T cells, isolated from skin biopsies of AD patients and healthy control subjects, alongside specific glycoanalysis of S. aureus strains isolated from the AD lesions. Our findings revealed 4 LC subpopulations ie, 2 steady-state clusters [LC1 and LC1H] and 2 proinflammatory/matured subsets [LC2 and migratory LCs]. The latter 2 subsets were enriched in AD skin. AD LCs showed enhanced expression of C-type lectin receptors, the high-affinity IgE receptor, and activation of prostaglandin and leukotriene biosynthesis pathways, upregulated transcriptional signatures related to T cell activation pathways, and increased expression of CCL17 compared with healthy LCs. Correspondingly, T helper 2 and T regulatory cell populations were increased in AD lesions. Complementary, we performed bulk RNA sequencing of primary LCs stimulated with the S. aureus strains isolated from the AD lesions, which showed upregulation of T helper 2-related pathways. Our study provides proof-of-concept for a role of LCs in connecting the S. aureus-T cell axis in the AD inflammatory cycle.

Cosmic voids and the kinetic analysis IV. Hubble tension and the cosmological constant

The formation of cosmic structures in the late Universe was considered using the Vlasov kinetic approach. The crucial point is the use of the gravitational potential with repulsive term of the cosmological constant, which provides a solution to the Hubble tension, that is, the Hubble parameter for the late Universe has to differ from its global cosmological value. This also provides a mechanism of formation of stationary semi-periodic gravitating structures of voids and walls, so that the cosmological constant has the role of the scaling. It can therefore be compared with the observational data for given regions. The considered mechanism of the structure formation in the late cosmological epoch then succeeds the epoch described by the evolution of primordial density fluctuations.

The Dynamics, Degradation, and Afterlives of Pectins: Influences on Cell Wall Assembly and Structure, Plant Development and Physiology, Agronomy, and Biotechnology.

Pectins underpin the assembly, molecular architecture, and physical properties of plant cell walls and through their effects on cell growth and adhesion influence many aspects of plant development. They are some of the most dynamic components of plant cell walls, and pectin remodeling and degradation by pectin-modifying enzymes can drive developmental programming via physical effects on the cell wall and the generation of oligosaccharides that can act as signaling ligands. Here, we introduce pectin structure and synthesis and discuss pectin functions in plants. We highlight recent advances in understanding the structure-function relationships of pectin-modifying enzymes and their products and how these advances point toward new approaches to bridging key knowledge gaps and manipulating pectin dynamics to control plant development. Finally, we discuss how a deeper understanding of pectin dynamics might enable innovations in agronomy and biotechnology, unlocking new benefits from these ubiquitous but complex polysaccharides.

Multidirectional Reorientation in the Ferroelastic van der Waals Semimetal Molybdenum Ditelluride

AbstractFerroelastic properties in two‐dimensional materials have garnered significant attention due to their potential to control structural anisotropy, thereby influencing optical and electrical characteristics under external stress. Despite these potential applications, there remains a scarcity of reports on ferroelastic behavior in two‐dimensional van der Waals materials. In this study, we investigate multidirectional ferroelastic reorientation in the two‐dimensional van der Waals semimetallic phase of Molybdenum ditelluride (1T′ MoTe2). Employing a polymer encapsulation method, ferroelastic switching in 1T′ MoTe2 is examined via real‐time polarized optical imaging under uniaxial strain. Polarized Raman spectroscopy confirms the orientation of Mo–Mo chains in original and reoriented domains, revealing 120° rotational switching in reconstructed domains. Analysis using selective area electron diffraction and scanning transmission electron microscopy elucidate the atomic arrangements of original and reconstructed domains, including domain wall structures. Additionally, it is demonstrated that external uniaxial strain can differentiate between the stabilities of three equivalent states in 1T′ MoTe2, enabling manipulation of the orientation of Mo–Mo chains based on the direction of the applied strain. The findings highlight the capability for multidirectional ferroelastic reorientation in the two‐dimensional semimetal MoTe2 through the application of uniaxial strain.

Runaway electron beam formation, vertical motion, termination and wall loads in EU-DEMO

Abstract Runaway electron loads onto material structures are a major concern for future large tokamaks due to the efficient avalanching at high plasma currents. &amp;#xD;Here, we perform predictive numerical studies using the JOREK code for a plausible plasma configuration in the European DEMO fusion power plant, focusing in this paper on the scenario where the highest multi-ampere runaway electron beam is formed.&amp;#xD;The work first comprises axisymmetric predictions of runaway electron beam formation in a mitigated scenario and of the simultaneous vertical motion of the beam due to loss of position control. The subsequent runaway electron beam termination triggered by a burst of MHD activity during the course of the vertical motion is then simulated in 3D with the runaway electron fluid self-consistently coupled to the MHD modes. Finally, the resulting deposition pattern of the runaway electrons onto wall structures is calculated with a relativistic test particle approach. This way, the suitability of a possible sacrificial limiter concept for the protection of first wall components is assessed.

Seismic Performance and Flexural Capacity Analysis of Embedded Steel Plate Composite Shear Wall Structure with Fiber-Reinforced Concrete in the Plastic Hinge Zone

Due to its high axial bearing capacity and good ductility, the embedded steel plate composite shear wall structure has become one of the most widely used lateral force-resisting structural members in building construction. However, bending failure is prone to occur during strong earthquakes, and the single energy dissipation mechanism of the plastic hinge zone at the bottom leads to the concentration of local wall damage. To improve the embedded steel plate composite shear wall structure, the plastic hinge zone of the composite shear wall is replaced by fiber-reinforced concrete (FRC) and analyzed by ABAQUS finite element simulation analysis. Firstly, the structural model of the embedded steel plate composite shear wall structure with FRC in the plastic hinge zone is established and the accuracy of the model is verified. Secondly, the effects of steel ratio, longitudinal reinforcement ratio, and FRC strength on the bearing capacity of composite shear walls are analyzed by numerical simulation. Finally, a method for calculating the embedded steel plate composite shear wall structure with FRC in the plastic hinge zone is proposed. It is shown that the displacement and load curves and failure modes of the model are basically consistent with the experimental results, and the model has high accuracy. The axial compression ratio and FRC strength have a great influence on the bearing capacity of composite shear walls. The calculation formula of the normal section bending capacity of the embedded steel plate composite shear wall structure with FRC in the plastic hinge zone is proposed. The calculated values of the bending capacity are in good agreement with the simulated values, which can provide a reference for its engineering application.

A simple and highly efficient protocol for 13C-labeling of plant cell wall for structural and quantitative analyses via solid-state nuclear magnetic resonance

BackgroundPlant cell walls are made of a complex network of interacting polymers that play a critical role in plant development and responses to environmental changes. Thus, improving plant biomass and fitness requires the elucidation of the structural organization of plant cell walls in their native environment. The 13C-based multi-dimensional solid-state nuclear magnetic resonance (ssNMR) has been instrumental in revealing the structural information of plant cell walls through 2D and 3D correlation spectral analyses. However, the requirement of enriching plants with 13C limits the applicability of this method. To our knowledge, there is only a very limited set of methods currently available that achieve high levels of 13C-labeling of plant materials using 13CO2, and most of them require large amounts of 13CO2 in larger growth chambers.ResultsIn this study, a simplified protocol for 13C-labeling of plant materials is introduced that allows ca 60% labeling of the cell walls, as quantified by comparison with commercially labeled samples. This level of 13C-enrichment is sufficient for all conventional 2D and 3D correlation ssNMR experiments for detailed analysis of plant cell wall structure. The protocol is based on a convenient and easy setup to supply both 13C-labeled glucose and 13CO2 using a vacuum-desiccator. The protocol does not require large amounts of 13CO2.ConclusionThis study shows that our 13C-labeling of plant materials can make the accessibility to ssNMR technique easy and affordable. The derived high-resolution 2D and 3D correlation spectra are used to extract structural information of plant cell walls. This helps to better understand the influence of polysaccharide-polysaccharide interaction on plant performance and allows for a more precise parametrization of plant cell wall models.

Understanding pectin cross-linking in plant cell walls

Pectin is a major component of plant cells walls. The extent to which pectin chains crosslink with one another determines crucial properties including cell wall strength, porosity, and the ability of small, biologically significant molecules to access the cell. Despite its importance, significant gaps remain in our comprehension, at the molecular level, of how pectin cross-links influence the mechanical and physical properties of cell walls. This study employs a multidisciplinary approach, combining molecular dynamics simulations, experimental investigations, and mathematical modelling, to elucidate the mechanism of pectin cross-linking and its effect on cell wall porosity. The computational aspects of this work challenge the prevailing egg-box model, favoring instead a zipper model for pectin cross-linking, whilst our experimental work highlights the significant impact of pectin cross-linking on cell wall porosity. This work advances our fundamental understanding of the biochemistry underpinning the structure and function of the plant cell wall. This knowledge has important implications for agricultural biotechnology, informing us about the chemical properties of plant pectins that are best suited for improving crop resilience and amenability to biofuel extraction by modifying the cell wall.

Scaling behavior and emergent conductance plateau with uniform conductance distribution in disordered topological insulators with a domain wall structure

Scaling behavior and emergent conductance plateau with uniform conductance distribution in disordered topological insulators with a domain wall structure

The influence of metro operation vibration on single-layer cable net glass curtain wall structure based on frequency method

The influence of metro operation vibration on single-layer cable net glass curtain wall structure based on frequency method

Comparative analysis of small-incision and traditional techniques in costal cartilage harvesting: Outcomes on thoracic deformities and scar appearance.

This study aims to compare the postoperative thoracic deformity and scar aesthetic outcomes of auricular reconstruction between the conventional large-incision technique and small-incision technique with perichondrium preservation for costal cartilage harvesting. A retrospective analysis was performed on 134 patients who underwent auricular reconstruction using tissue expanders and autologous costal cartilage harvested from the right chest wall between January 2021 and September 2023. Patients were divided into two groups according to the harvesting technique: the traditional large-incision group (n=64) and the small-incision group with perichondrium preservation (n=70). Preoperative and postoperative chest CT scans were reviewed for thoracic deformities by measurements of the modified Haller Index (mHI) and modified correction index (mCI). Thoracic scar dimensions were measured in postoperative follow-up. In the conventional group, significant difference were observed between the left and right hemithorax in anterior-posterior diameter, maximum transverse diameter, cross-sectional area, and mHI values (p<0.05), showing thoracic deformities. In contrast, within the small-incision group, there were no significant differences between hemithoraces. Additionally, postoperative thoracic scars were significantly smaller in the small-incision group, with shorter scar length (5.63±1.33 cm vs. 11.44±1.31cm) and width (1.41±0.55cm vs. 3.75±1.54cm; p<0.001). The small-incision technique with perichondrium preservation significantly reduces postoperative thoracic deformities and results in smaller, less conspicuous scars compared to the traditional large-incision method. This approach minimizes disruption to the chest wall structure and reduces donor-site morbidity, offering improved patient outcomes.

Preventive maintenance on highway roads

Dangerous geological processes such as landslides, mudflows, rockfalls, and bank erosion are observed in many regions of Russia. This paper aims to expand the classification of works on engineering protection of highway sections from hazardous geological processes to reduce the risk of emergencies. The issues of engineering protection of highways are considered, as well as the principles (conditions) formed in the process of their construction, which provide for timely organizational and constructive decisions at the stages of design and subsequent operation. According to the Decree of the Ministry of Transport of the Russian Federation No. 402 dated November 16, 2012, the following classification of works was approved: overhaul, repair of highways, maintenance works of highways. Not only designing new means of engineering protection of highways, but also maintaining the proper functioning of existing ones is relevant for specialists in the field of road construction. A list of recommended measures is designed to ensure reliable and fail-safe operation of retaining walls as well as to analyze the technical condition of landslide protection structures for subsequent measures to prevent emergencies. The present paper indicates a new type of work, i.e. preventive maintenance works, which may involve minor modifications to the retaining wall structure to strengthen it. When they are performed, overhaul of the site is not required.

Brassinosteroids Render Cell Walls Softer but Less Extensible in Growing Arabidopsis Hypocotyls.

Cell wall extensibility is a key biophysical characteristic that defines the rate of plant cell growth. It depends on the wall structure and is controlled by numerous proteins that cut and/or (re)form links between the wall constituents. Cell wall extensibility is currently estimated by different in vitro biomechanical tests. We used the creep method, in which isolated cell walls are extended under a constant load and their time-dependent deformation (creep) is recorded to reveal the biophysical basis of growth inhibition of Arabidopsis thaliana hypocotyls in the presence of 24-epibrassinolide (EBL), one of the most active natural brassinosteroids. We found that EBL rendered the walls of hypocotyl cells softer, i.e., more deformable under mechanical force, which was revealed using heat-inactivated cell walls to eliminate endogenous activities of cell-wall-loosening/tightening proteins. This effect was caused by the altered arrangement of cellulose microfibrils. At the same time, EBL made the walls less extensible, which was detected with native walls under conditions optimized for activities of endogenous cell-wall-loosening proteins. These apparently conflicting changes in the wall mechanics can be an adaptation by which EBL enables plant cells to grow under stress conditions.

Studies on Shielding and Activation Levels in a Concrete-Iron-Concrete Sandwich Structure Wall in the CMUH Proton Therapy Facility.

The shielding performance and activation susceptibility of a sandwich wall in the proton therapy facility of China Medical University Hospital were investigated in an integrated manner using FLUKA Monte Carlo simulations. The 2-m-thick partition wall between two adjoining treatment rooms had a three-layered structure, which comprised a 0.2-m-thick iron layer sandwiched between two layers of 0.9-m-thick concrete. In comparison with that of a concrete wall of the same thickness, the shielding performance of the concrete-iron-concrete wall was marginally better, further reducing the transmitted dose rate by approximately a factor of 2 against secondary neutrons generated through proton bombardment. This study also investigated radioactivity levels from long-lived radionuclides (3H, 22Na, 54Mn, 55Fe, 60Co, 134Cs, 152Eu, and 154Eu) that are primarily induced in concrete or iron by neutrons. The specific activities of 54Mn, 55Fe, and 60Co in the middle iron layer were considerably higher (by factors of 75, 25, and 5, respectively) than those in the neighboring concrete. However, as for clearance levels, the index value of the iron layer was lower than that of the neighboring concrete because of the presence of fewer types of long-lived radionuclides in iron. Under irradiation scenarios considered in this study, the residual activity levels of the sandwich wall do not exceed those of a full-concrete wall, and the indexes at various depths estimated at 5 years cooling following a 20-y operational period comply with clearance criteria.

The Genetic Determinants of Listeria monocytogenes Resistance to Bacteriocins Produced by Lactic Acid Bacteria.

Listeria monocytogenes is a Gram-positive bacterium responsible for listeriosis, a serious foodborne disease that can lead to serious health complications. Pregnant women, newborns, the elderly, and patients with weakened immune systems are particularly susceptible to infection. Due to the ability of L. monocytogenes to survive in extreme environmental conditions, such as low temperatures, high salinity, and acidity, this bacterium poses a serious threat to food production plants and is particularly difficult to eliminate from these plants. One of the promising solutions to reduce the presence of this bacterium in food products is bacteriocins as natural control agents. These are substances with antibacterial activity produced by other bacteria, mainly lactic acid bacteria (LAB), which can effectively inhibit the development of pathogens such as L. monocytogenes. The use of bacteriocins in the food industry is beneficial due to their natural origin, specificity of action, and consumer safety. However, the problem of resistance to these substances exists. This review focuses on the mechanisms of bacteriocin resistance, such as modifications of bacteriocin docking receptors, changes in the structure of the cell wall and membrane, and the occurrence of cross-resistance to different bacteriocins. Genetic factors determining these mechanisms and strategies to cope with the problem of resistance are also presented. Research on this issue is crucial for developing effective preventive methods that will enable the safe and long-term use of bacteriocins in food production.