Wall Reinforcement Research Articles

High Mining Face Flexible Reinforcement to Prevent Coal Wall Spalling by Cuttable Aluminum–Plastic Pipe Pre-Grouting

A larger mining height leads to easy caving of the coal wall in the working face. The flexible reinforcement method during the mining period of the working face affects the normal mining of the working face, and the high strength of the traditional bolt/cable material affects the operation of the shearer drum, so it is necessary to seek a reinforcement material which does not affect the production and the drum coal cutting. This paper proposed a technical scheme of coal wall reinforcement by pre-grouting with a cuttable aluminum–plastic composite pipe which is easy to cut during mining in the working face, tested the mechanical properties of the “grouting + flexible pipe” specimen, and obtained the optimal support spacing by numerical simulation and carrying out an industrial test. The results show that the tensile strength of aluminum–plastic composite pipe is much higher than that of coal spalling and the elongation is much higher than that of the anchor rod. When double-row composite grouting holes are arranged 1.5 and 3.0 m away from the roof, the supporting effect is better. Underground grouting shows that pre-grouting before mining according to the advancing speed of the working face 10–14 days in advance can effectively fill the coal cracks and significantly improve the integrity of the coal wall.

Pre and post stage of infection of Magnaporthe oryzae Oryza in wheat leaves with different resistance levels.

Blast fungus (Magnaporthe oryzae B.C. Couch) is an imminent threat to global food security because it causes serious yield losses in rice (Oryza sativa L.) and wheat (Triticum aestivum L.). The investigation of infection processes in resistant and susceptible varieties, as well as the cellular responses involved in resistance, can help us to better understand the process of interaction of the M. oryzae-Poaceae pathosystems. Thus, the objectives of this study were to evaluate the processes of pre- and post-infection of M. oryzae in leaves of wheat varieties with different levels of resistance. The percentage of germinated conidia, appressorium formed, tissue penetration and colonization, and the reaction of leaf tissue to infection were evaluated. A decrease was observed in the percentage of germinated conidia, appressorium formation, tissue penetration and colonization, especially in the tissues of resistant varieties, in addition to an increase in the plant's response to infection, with cell wall reinforcement, cell death, and autofluorescent cytoplasm aggregation. Nevertheless, our data produced a different temporal perspective regarding the expression of the known types of resistance. We found that, for a single genotype, recognition can start as early as 6h after inoculation and continue to evolve until very late during the infection cycle, culminating in cell death. The combined and overlapping pre- and post-haustorial resistance mechanisms were sufficient to prevent disease symptoms, with a few punctual lesions observed in one of the resistant varieties (BR 18) and no visible symptoms in the other two (Ônix or BRS229) as opposed to susceptible variety.

Exploring leaf hydraulic traits to predict drought tolerance of Eucalyptus clones.

Ongoing changes in climate, and the consequent mortality of natural and cultivated forests across the globe, highlight the urgent need to understand the plant traits associated with greater tolerance to drought. Here, we aimed at assessing key foliar traits, with a focus on the hydraulic component, that could confer a differential ability to tolerate drought in three commercial hybrids of the most important Eucalyptus species utilized in tropical silviculture: E. urophyla, E. grandis and E. camaldulensis. All genotypes exhibited similar water potential when the 90% stomatal closure (Ψgs90) occurs with Ψgs90 always preceding the start of embolism events. The drought-tolerant hybrid showed a higher leaf resistance to embolism, but the leaf hydraulic efficiency was similar among all genotypes. Other traits presented by the drought-tolerant hybrid were a higher cell wall reinforcement, lower value of osmotic potential at full turgor and greater bulk modulus of elasticity. We also identified that the leaf capacitance after the turgor loss, the ratio between cell wall thickness (t) and lumen breadth (b) ratio (t/b)3, and the minimal conductance might be good proxies for screening drought-tolerant Eucalyptus genotypes. Our findings suggest that xylem resistance to embolism can be an important component of drought tolerance in Eucalyptus in addition to other traits aimed at delaying the development of high tensions in the xylem. Highlight Drought tolerance in tropical Eucalyptus hybrids encompasses a high leaf resistance to embolism and a suite of traits aimed at delaying the development of high tensions in the xylem.

Tropical Plant Species Living Under P Limitation Show Signs of Greater Resistance to Drought

AbstractTropical forests are fundamental in the global water and carbon cycles, yet they are under threat of drought induced mortality. Tropical forests typically grow in phosphorus (P) pool soils. Through compiling data from tropical forests around the world, we showed that multiple tropical species acclimated to P deficiency have a higher hydraulic safety margin, which means they are less vulnerable to hydraulic failure. Through detailed experiments in subtropical China, we further uncovered the underlying mechanism is that species acclimated to P deficiency would have higher the stem area: leaf area ratio and strengthening vessel wall reinforcement. Our finding highlights the importance of including P availability into models when forecast the mortality risk of tropical forest in response to climate changes.

Cell-wall structural carbohydrates reinforcements are part of the defence mechanisms of wheat against Russian wheat aphid (Diuraphis noxia) infestation

Russian wheat aphid (RWA) is one of the most challenging pests for wheat crops globally. In South Africa, RWA has breached the strategy of introducing resistant genes into wheat plants, and so far, five RWA biotypes with different virulence levels have been documented in the field. Our study investigated how the cell wall plays a defensive role in Tugela-Dn1 (susceptible) and-Dn5 (resistant) cultivars infested with South African RWA-biotype 2 (RWASA2). The activities of enzymes related to defense responses were measured. The cell wall's holo-cellulose content, soluble lignin and physicochemical changes were quantified in the infested susceptible and resistant cultivars. Lastly, in vitro RWASA2 saliva-associated CWDEs activity was determined on cell wall-related model substrates. The results show that apoplastic peroxidase and β-1,3-glucanase activities were significantly higher in Tugela-Dn5 relative to the control during the infestation periods. Peroxidase activity is associated with lignin cross-linking of the cell wall, which could deter RWASA2 feeding. The total phenolic and holo-cellulose contents were significantly induced in Tugela-Dn5 at 72 and 120 h post infestation (hpi). These findings were corroborated by the FTIR results, which showed that holocellulose and lignin regions of the resistant and susceptible wheat were affected by infestation at 72 hpi. However, Tugela-Dn5 reinforced cell wall content at 120 hpi. An increased crystallinity index in the resistant cultivar validated the cell wall reinforcement at 120 hpi, while Tugela-Dn1 delayed cell wall reinforcement. This study demonstrates that cell wall reinforcement's modification is part of defense responses against Russian wheat aphid infestation.

Genome-wide identification and characterization of Fusarium circinatum-responsive lncRNAs in Pinus radiata

BackgroundOne of the most promising strategies of Pine Pitch Canker (PPC) management is the use of reproductive plant material resistant to the disease. Understanding the complexity of plant transcriptome that underlies the defence to the causal agent Fusarium circinatum, would greatly facilitate the development of an accurate breeding program. Long non-coding RNAs (lncRNAs) are emerging as important transcriptional regulators under biotic stresses in plants. However, to date, characterization of lncRNAs in conifer trees has not been reported. In this study, transcriptomic identification of lncRNAs was carried out using strand-specific paired-end RNA sequencing, from Pinus radiata samples inoculated with F. circinatum at an early stage of infection.ResultsOverall, 13,312 lncRNAs were predicted through a bioinformatics approach, including long intergenic non-coding RNAs (92.3%), antisense lncRNAs (3.3%) and intronic lncRNAs (2.9%). Compared with protein-coding RNAs, pine lncRNAs are shorter, have lower expression, lower GC content and harbour fewer and shorter exons. A total of 164 differentially expressed (DE) lncRNAs were identified in response to F. circinatum infection in the inoculated versus mock-inoculated P. radiata seedlings. The predicted cis-regulated target genes of these pathogen-responsive lncRNAs were related to defence mechanisms such as kinase activity, phytohormone regulation, and cell wall reinforcement. Co-expression network analysis of DE lncRNAs, DE protein-coding RNAs and lncRNA target genes also indicated a potential network regulating pectinesterase activity and cell wall remodelling.ConclusionsThis study presents the first comprehensive genome-wide analysis of P. radiata lncRNAs and provides the basis for future functional characterizations of lncRNAs in relation to pine defence responses against F. circinatum.

Translocation of Foliar Absorbed Zn in Sunflower (Helianthus annuus) Leaves.

Foliar zinc (Zn) fertilization is an important approach for overcoming crop Zn deficiency, yet little is known regarding the subsequent translocation of this foliar-applied Zn. Using synchrotron-based X-ray fluorescence microscopy (XFM) and transcriptome analysis, the present study examined the translocation of foliar absorbed Zn in sunflower (Helianthus annuus) leaves. Although bulk analyses showed that there had been minimal translocation of the absorbed Zn out of the leaf within 7 days, in situ analyses showed that the distribution of Zn in the leaf had changed with time. Specifically, when Zn was applied to the leaf for 0.5 h and then removed, Zn primarily accumulated within the upper and lower epidermal layers (when examined after 3 h), but when examined after 24 h, the Zn had moved to the vascular tissues. Transcriptome analyses identified a range of genes involved in stress response, cell wall reinforcement, and binding that were initially upregulated following foliar Zn application, whereas they were downregulated after 24 h. These observations suggest that foliar Zn application caused rapid stress to the leaf, with the initial Zn accumulation in the epidermis as a detoxification strategy, but once this stress decreased, Zn was then moved to the vascular tissues. Overall, this study has shown that despite foliar Zn application causing rapid stress to the leaf and that most of the Zn stayed within the leaf over 7 days, the distribution of Zn in the leaf had changed, with Zn mostly located in the vascular tissues 24 h after the Zn had been applied. Not only do the data presented herein provide new insight for improving the efficiency of foliar Zn fertilizers, but our approach of combining XFM with a transcriptome methodological system provides a novel approach for the study of element translocation in plants.

Induced ligno‐suberin vascular coating and tyramine‐derived hydroxycinnamic acid amides restrict Ralstonia solanacearum colonization in resistant tomato

Tomato varieties resistant to the bacterial wilt pathogen Ralstonia solanacearum have the ability to restrict bacterial movement in the plant. Inducible vascular cell wall reinforcements seem to play a key role in confining R. solanacearum into the xylem vasculature of resistant tomato. However, the type of compounds involved in such vascular physico-chemical barriers remain understudied, while being a key component of resistance. Here we use a combination of histological and live-imaging techniques, together with spectroscopy and gene expression analysis to understand the nature of R. solanacearum-induced formation of vascular coatings in resistant tomato. We describe that resistant tomato specifically responds to infection by assembling a vascular structural barrier formed by a ligno-suberin coating and tyramine-derived hydroxycinnamic acid amides. Further, we show that overexpressing genes of the ligno-suberin pathway in a commercial susceptible variety of tomato restricts R. solanacearum movement inside the plant and slows disease progression, enhancing resistance to the pathogen. We propose that the induced barrier in resistant plants does not only restrict the movement of the pathogen, but may also prevent cell wall degradation by the pathogen and confer anti-microbial properties, effectively contributing to resistance.

Biochemical and Histological Insights into the Interaction Between the Canker Pathogen Neofusicoccum parvum and Prunus dulcis.

The number of reports associated with wood dieback caused by fungi in the Botryosphaeriaceae in numerous perennial crops worldwide has significantly increased in the past years. In this study, we investigated the interactions between the canker pathogen Neofusicoccum parvum and the almond tree host (Prunus dulcis), with an emphasis on varietal resistance and host response at the cell wall biochemical and histological levels. Plant bioassays in a shaded house showed that among the four commonly planted commercial almond cultivars ('Butte', 'Carmel', 'Monterey', and 'Nonpareil'), there was no significant varietal difference with respect to resistance to the pathogen. Gummosis was triggered only by fungal infection, not by wounding. A two-dimensional nuclear magnetic resonance and liquid chromatography determination of cell wall polymers showed that infected almond trees differed significantly in their glycosyl and lignin composition compared with healthy, noninfected trees. Response to fungal infection involved a significant increase in lignin, a decrease in glucans, and an overall enrichment in other carbohydrates with a profile similar to those observed in gums. Histological observations revealed the presence of guaiacyl-rich cell wall reinforcements. Confocal microscopy suggested that N. parvum colonized mainly the lumina of xylem vessels and parenchyma cells, and to a lesser extent the gum ducts. We discuss the relevance of these findings in the context of the compartmentalization of decay in trees model in almond and its potential involvement in the vulnerability of the host toward fungal wood canker diseases.

Wind-induced collapse mechanism and failure criteria of super-large cooling tower based on layered shell element model

Many wind-induced collapse events of super-large cooling tower have been taken place in history. Existing norms are limited within local excessive strength or buckling failure of the tower body, but ignore the follow-up phenomena after the general continuous collapse caused by local damages. Hence, they are difficult to disclose the wind-induced collapse mechanism and failure mechanism of super-large cooling tower. A case study on the world highest (228 m) cooling tower under construction in Northwest China was carried out. Variations of multi-scale wall thickness and reinforcement ratio at different positions of the tower body were considered by the layered shell element modeling method. The wind loads on the cooling tower surface were acquired through a wind tunnel test of pressure measurement on the rigid body. Displacement and internal force responses of the tower body under typical wind speeds were analyzed by combining the incremental dynamic analysis (IDA), thus determining the critical wind speed. Three redistribution of internal forces mechanisms during collapse of tower body were extracted based on the stress variation indexes before and after the node failure. Moreover, the development paths of three collapse mechanisms among units with different thicknesses of the tower body were discussed. Finally, the wind-induced failure criteria of super-large cooling tower structure were proposed based on throat deformation of the tower body. Research results demonstrated that the layered shell element model could simulate the full process of collapse of super-large cooling tower effectively and a central damage area from the throat of windward side to the center of tower body was formed. Subsequently, a crack network was formed after diffusion of the damage area along the circumferential and meridian until the complete collapse. Three redistribution mechanisms of internal forces during the collapse of the super-large cooling tower were proposed, including the sliding surface mechanism, rotating hinge mechanism and slipping surface mechanism. The super-large cooling tower structure developed wind-induced failure and collapse when the deformation failure index is δ ≥ 1.5%. It is of great significance to the design and construction of super-large cooling towers.

Numerical analysis of lightweight concrete wall panels having a variation of dimensions and openings that were subjected to static lateral loads

Wall panels are non-structural parts of buildings that are considered dead loads. The mass of wall panels must be reduced to minimize earthquake risk and enhance structural resistance to lighter dead loads. This study used wall panel models that consisted of lightweight foamed concrete materials containing expanded polystyrene. The wall panels used in this study also had a variety of dimensions and reinforcements. The effect of openings on wall panel model performance was also investigated. This study aimed to analyze the performance of lightweight concrete wall panel models under static lateral loads applied until the ultimate condition. It was found that the load-deformation relation performs varying values of stiffness, strength, and ductility depended on the wall panel dimensions, reinforcements, and openings. A wall panel model with a height of 1000 mm that had length of 1500 mm and thickness of 60 mm with wire mesh and without openings achieved the highest ultimate stiffness and strength. The highest ductility was achieved by a wall panel model with openings, without wire mesh, with height, length, and thickness of 1500 mm, 1500 mm, and 40 mm, respectively. Diagrams of the deformations in this paper reflect the compressed and tensioned areas. The lefthand parts of all wall panel models without wire mesh were tensioned and had concentrations of deformation in those areas. The existence of openings also caused increased deformation due to less stiffness in the wall panel models.

Out-of-Plane Strengthening of Unreinforced Masonry Walls by Glass Fiber-Reinforced Polyurea

Fiber-reinforced polymer reinforcement or polyurea reinforcement techniques are applied to strengthen unreinforced masonry walls (UMWs). The purpose of this experimental study is to verify the out-of-plane reinforcing effect of sprayed glass fiber-reinforced polyurea (GFRPU), which is a composite elastomer made of polyurea and milled glass fibers on UMW. The out-of-plane strengths and ductile behaviors based on various coating shapes are compared in this study. An empirical formula to describe the degree of reinforcement on the out-of-plane strength of the UMW is derived based on the experimental results. It is observed that the peak load-carrying capacity, ductility, and energy absorption capacity gradually improve with an increase in the strengthening degree or area. Compared with the existing masonry wall reinforcement method, the GFRPU technique is a construction method that can help improve the safety performance along with ease of construction and economic efficiency. Doi: 10.28991/CEJ-2022-08-01-011 Full Text: PDF

Dissecting the susceptibility/resistance mechanism of Vitis vinifera for the future control of downy mildew

The Eurasian grapevine (Vitis vinifera), a species cultivated worldwide for high-quality wine production, is extremely susceptible to the agent of downy mildew, Plasmopara viticola. Nevertheless, germplasm from Georgia (Southern Caucasus, the first grapevine domestication centre), characterized by a high genetic variability, showed resistance traits to P. viticola. The cultivar Mgaloblishvili exhibited the most promising phenotype in terms of resistance against P. viticola. Its defence response results in: i) low disease intensity; ii) low sporulation; iii) damaged mycelium; iv) production of antimicrobial compounds such as volatile organic compounds (VOCs), whose effectiveness on the pathogen was evaluated by leafdisc assays. At the transcriptomic level, its resistance mechanism is determined by the differential expression of both resistance and susceptible genes. The resistance genes are related to: i) pathogen recognition through PAMP, DAMP and effector receptors; ii) ethylene signalling pathway; iii) synthesis of antimicrobial compounds (VOCs) and fungal wall degrading enzymes; iv) development of structural barriers (cell wall reinforcement). The first putative susceptible gene was the transcription factor VviLBDIf7 gene, whose validation was carried out by dsRNA (double-stranded RNA) assay. In this work, these unique results on plant-pathogen interaction are reviewed with the aim of developing new strategies to control the disease.

Apexification and dentinal wall reinforcement using Biodentine and glass fiber post

A 21-year-old male patient reported with chief complaint of pain in the upper front teeth. Clinical examination revealed tooth fracture in teeth # 11, 21, and prior attempted endodontic treatment. The radiographic examination revealed periapical radiolucency in relation to upper central incisors with thinning of dentinal walls. The upper left central incisor had grossly diminished root canal dentin walls with immature apex, whereas the upper right central incisor had moderate loss of dentin from the root canal wall with an open apex. Hence, it was decided to extract the upper left central incisor, whereas apexification and root canal dentin wall reinforcement with Biodentine were carried out for the upper right central incisor. The patient was asymptomatic at 1-, 4-, and 6-month follow-up visits.

Tracheid and Pit Dimensions Hardly Vary in the Xylem of Pinus sylvestris Under Contrasting Growing Conditions.

Maintaining sufficient water transport via the xylem is crucial for tree survival under variable environmental conditions. Both efficiency and safety of the water transport are based on the anatomical structure of conduits and their connections, the pits. Yet, the plasticity of the xylem anatomy, particularly that of the pit structures, remains unclear. Also, trees adjust conduit dimensions to the water transport distance (i.e., tree size), but knowledge on respective adjustments in pit dimensions is scarce. We compared tracheid traits [mean tracheid diameter d, mean hydraulic diameter dh, cell wall reinforcement (t/b)2], pit dimensions (diameters of pit aperture Da, torus Dt, margo Dm, and pit border Dp), and pit functional properties (margo flexibility F, absolute overlap Oa, torus overlap O, and valve effect Vef) of two Scots pine (Pinus sylvestris L.) stands of similar tree heights but contrasting growth rates. Furthermore, we analyzed the trends of these xylem anatomical parameters across tree rings. Tracheid traits and pit dimensions were similar on both sites, whereas Oa, O, and F were higher at the site with a lower growth rate. On the lower growth rate site, dh and pit dimensions increased across tree rings from pith to bark, and in trees from both sites, dh scaled with pit dimensions. Adjusted pit functional properties indicate slightly higher hydraulic safety in trees with a lower growth rate, although a lack of major differences in measured traits indicated overall low plasticity of the tracheid and pit architecture. Mean hydraulic diameter and pit dimension are well coordinated to increase the hydraulic efficiency toward the outer tree rings and thus with increasing tree height. Our results contribute to a better understanding of tree hydraulics under variable environmental conditions.

An Experimental Study on the Seismic Performance of High-Strength Composite Shear Walls

In order to study the seismic performance of high-strength concrete composite shear walls with embedded steel strips, four tests for high-strength concrete composite shear walls with embedded steel strips (SPRCW-1 to SPRCW-4) were constructed and tested. Based on the test results, a discussion is provided in the present study on the hysteresis curve, backbone curves, and strain of steel plate and distributed reinforcement of high-strength concrete mid-rise and high-rise composite shear walls with embedded steel strips under different steel ratios and different steel strip positions. The test results reveal that in high-strength composite shear walls with embedded steel strips, the ductility of the test specimen can be effectively improved when the ratio of the steel strip reaches a certain level. In parallel, when the embedded steel strip is placed on both sides of the walls, the steel strip can function better. The ultimate displacement is better than when the steel strip is placed in the middle of the walls, and can effectively improve the seismic performance of the walls. The scheme with embedded steel strips is more convenient and economical for construction, which is suitable for popularization and application in middle-high buildings in highly seismic regions.

Experimental study on torsional behavior of thin- and thick-walled RC box-girders using BFRP bars and steel stirrups under combined torsion-shear-moment

Experiments on hollow FRP-RC members subjected to combined torsion are uncommon. Six specimens of identical size and length, five rectangular and one trapezoidal, were constructed and tested in this investigation. About 2.5 percent reinforcement is included in all of the specimens. The study variables were the effect of shape (rectangular vs trapezoidal), concrete wall thickness (thin vs thick), cover thickness, and reinforcement layout (single-layer vs double-layer). Strength and stiffness, deflection and angle of twist, cracking pattern, and modes of failure were all evaluated. It is discovered that a trapezoidal thin-walled box-girder can attain around 85% of the ultimate strength of its rectangular counterpart, with 9% less deflection and 11% more twist. Thin-walled box-girders have a 17 percent higher ultimate torsional capacity than thick-walled members with thick covers. Thin-walled box-girders have the least deflection and twist, but their ultimate torsional capacity is limited compared to thick-walled counterparts. In thick-walled members, utilizing a double layer of reinforcement instead of a single-layer, can result in just a 4% increase in ultimate strengths, while deflection and twist both drop by 23%; in addition, a double-layer reinforced box-girder with thicker webs than flanges can reach the largest ultimate strength with the least angle of twist at failure.

FERONIA and microtubules independently contribute to mechanical integrity in the Arabidopsis shoot.

To survive, cells must constantly resist mechanical stress. In plants, this involves the reinforcement of cell walls, notably through microtubule-dependent cellulose deposition. How wall sensing might contribute to this response is unknown. Here, we tested whether the microtubule response to stress acts downstream of known wall sensors. Using a multistep screen with 11 mutant lines, we identify FERONIA (FER) as the primary candidate for the cell’s response to stress in the shoot. However, this does not imply that FER acts upstream of the microtubule response to stress. In fact, when performing mechanical perturbations, we instead show that the expected microtubule response to stress does not require FER. We reveal that the feronia phenotype can be partially rescued by reducing tensile stress levels. Conversely, in the absence of both microtubules and FER, cells appear to swell and burst. Altogether, this shows that the microtubule response to stress acts as an independent pathway to resist stress, in parallel to FER. We propose that both pathways are required to maintain the mechanical integrity of plant cells.

Analysis on Key Process Control of Continuous Wall Reinforcement Cage Segmental Hoisting Construction under High-Speed Railway Station House

Analysis on Key Process Control of Continuous Wall Reinforcement Cage Segmental Hoisting Construction under High-Speed Railway Station House

Deciphering Molecular Host-Pathogen Interactions During Ramularia Collo-Cygni Infection on Barley.

Ramularia collo-cygni is the causal agent of Ramularia leaf spot disease (RLS) on barley and became, during the recent decades, an increasing threat for farmers across the world. Here, we analyze morphological, transcriptional, and metabolic responses of two barley cultivars having contrasting tolerance to RLS, when infected by an aggressive or mild R. collo-cygni isolate. We found that fungal biomass in leaves of the two cultivars does not correlate with their tolerance to RLS, and both cultivars displayed cell wall reinforcement at the point of contact with the fungal hyphae. Comparative transcriptome analysis identified that the largest transcriptional differences between cultivars are at the early stages of fungal colonization with differential expression of kinases, calmodulins, and defense proteins. Weighted gene co-expression network analysis identified modules of co-expressed genes, and hub genes important for cultivar responses to the two R. collo-cygni isolates. Metabolite analyses of the same leaves identified defense compounds such as p-CHDA and serotonin, correlating with responses observed at transcriptome and morphological level. Together these all-round responses of barley to R. collo-cygni provide molecular tools for further development of genetic and physiological markers that may be tested for improving tolerance of barley to this fungal pathogen.