Search Results (33)

In sub-Saharan Africa, land degradation and climate change continue to undermine agricultural productivity by reducing soil productivity and water availability. This review identifies soil and water conservation technologies successfully applied in climatically analogous regions of sub-Saharan Africa with the aim of informing effective technology transfer to Senegal, particularly Sédhiou and Tambacounda. Using K-means clustering on WorldClim bioclimatic variables, 35 comparable countries were identified, of which 17 met inclusion criteria based on data availability and ≥60% climatic similarity. Eighty-five technologies were documented and assessed for their compatibility across rainfall patterns, land gradients, and uses, with 12 emerging as consistently effective. Quantitative evidence shows that zai/tassa pits, stone bunds, and half-moons increase crop yields by 50–200%, while stone bunds and mulching reduce runoff by up to 80% and improve soil moisture retention. Terracing and tied-ridging were also linked to higher water-use efficiency, with tied-ridging increasing soil moisture by 13%. Burkina Faso, Kenya, and Malawi lead in adoption and diversity, whereas Senegal lags due to institutional gaps, limited funding, and weak extension systems. These technologies offer a readily available, evidence-based toolkit for building agricultural resilience in Senegal. However, their successful adoption requires stronger policy integration, stakeholder empowerment, cross-border learning, and private-sector engagement. Full article

Lianas are known for their distinctive vascular anatomy and remarkable hydraulic efficiency. Yet they exhibit considerable variation in hydraulic safety across and within forest types. This observation suggests different structure–functional strategies among lianas growing under contrasting levels of drought. Here, we compared xylem features at the cellular and intervessel pit levels and investigated their relationships with hydraulic safety and efficiency in five pairs of congeneric Bignonieae lianas from a seasonally dry forest (SDF) and a wet rainforest (RF). We hypothesize that rainforest lianas have xylem traits that maximize conductivity, while lianas from seasonally dry forests show greater woodiness and investment in storage tissues, and that xylem features at different levels drive the hydraulic safety and efficiency. The SDF liana species had a higher vessel density and grouping, and thinner fibers than rainforest lianas, but none of the features measured were related to hydraulic safety. Our results do not support that vessel or pit quantitative properties predict hydraulic safety in lianas. However, a higher hydraulic vessel diameter, total pit membrane area, and lower intervessel wall–lumen ratio were associated with high hydraulic efficiency, regardless of the forest type. These findings highlight the complexity of hydraulic structure–function relationships in lianas. While we found distinct xylem anatomical differences between species from contrasting forest types, only some traits were associated with hydraulic efficiency, and none predicted hydraulic safety, suggesting that other factors may be at play. Full article

Fast-growing hardwoods like poplar often lack natural durability in outdoor use and require homogeneous impregnation with protective agents, though achieving homogeneity remains a known challenge. Various anatomical structures influence fluid transport in wood. This study compares characteristics of pits in libriform fibres, between ray–vessel interfaces, and between vessel-to-vessel connections in normal wood and tension wood of a hybrid poplar genotype (Populus × canadensis, ‘Gelrica’), including both impregnated (with an aqueous, dye-containing solution) and non-impregnated regions, to identify anatomical barriers to impregnation. Light and scanning electron microscopy revealed significant differences in pit morphology and frequency in libriform fibres between normal wood and tension wood. In non-impregnated regions, pits were often encrusted. Vessel–ray pits did not differ between normal wood and tension wood but showed distinct differences between impregnated and non-impregnated regions: in the latter, pits were occluded by tylose-forming layers. Intervessel pits differed in border and aperture size between earlywood and latewood in both normal wood and tension wood. Hence, fluid transport is strongly impeded by occluded vessel–ray pits and, to a lesser extent, by encrusted fibre pits. Full article

The endemic Patagonian conifer, Austrocedrus chilensis, is threatened by the pathogen Phytophthora austrocedri. This study presents the first histological and histochemical analysis of A. chilensis affected by this pathogen. We examined the stem tissues of naturally infected adult trees (over 30 years old) and artificially inoculated saplings (8–12 years old) to identify the pathogen’s colonization strategies and the tree’s histological responses. Using light and scanning electronic microscopy along with several histochemical techniques (Lugol, toluidine blue, vanillin-HCl, Phloroglucinol, Calcofluor white, and aniline blue), we found that P. austrocedri can grow in all active tissues, leading to cambium and parenchyma necrosis. The pathogen spreads through sieve cells and tracheids, moving to the adjacent cells via sieve plates and bordered pits and colonizing nearby parenchyma cells. We observed loss of starch in necrotic tissues. In contrast, starch accumulation and an increase in the number of polyphenolic cells occur in the healthy areas adjacent to the margins of the lesion, indicating a tree’s induced defense mechanisms. The tree’s responses include cambium reprogramming, which leads to the formation of traumatic resin ducts, alterations in cell shape and size, and the deposition of phenolic compounds. We analyze the tree responses and discuss their potential relationship with a methyl jasmonate-induced defense and a hypersensitive-like response. Full article

Wood displays three-dimensional characteristics at both macroscopic and microscopic scales. Accurately reconstructing its 3D structure is vital for a deeper understanding of the relationship between its anatomical characteristics and its physical and mechanical properties. This study aims to apply X-ray micro-computed tomography (XμCT) for the high-resolution, non-destructive visualization and quantification of softwood anatomical features. Six typical softwood species—Picea asperata, Cupressus funebris, Pinus koraiensis, Pinus massoniana, Cedrus deodara, and Pseudotsuga menziesii—were selected to represent a range of structural characteristics. The results show that a scanning resolution of 1–2 μm is suitable for investigating the transition from earlywood to latewood and resin canals, while a resolution of 0.5 μm is required for finer structures such as bordered pits, ray tracheids, and cross-field pits. In Pinus koraiensis, a direct 3D connection between radial and axial resin canals was observed, forming an interconnected resin network. In contrast, wood rays were found to be distributed near the surface of axial resin canals but without forming interconnected structures. The three-dimensional reconstruction of bordered pit pairs in Pinus massoniana and Picea asperata clearly revealed interspecific differences in pit morphology, distribution, and volume. The average surface area and volume of bordered pit pairs in Pinus massoniana were 1151.60 μm² and 1715.35 μm³, respectively, compared to 290.43 μm² and 311.87 μm³ in Picea asperata. Furthermore, XμCT imaging effectively captured the morphology and spatial distribution of cross-field pits across species, demonstrating its advantage in comprehensive anatomical deconstruction. These findings highlight the potential of XμCT as a powerful tool for 3D analysis of wood anatomy, providing deeper insight into the structural complexity and interconnectivity of wood. Full article

Future automotive mobility is predominantly electric. Compared to existing systems, the requirements of subsystems change. Air flow for cooling components is needed predominantly when the car is in rest (i.e., charging) or at slow speeds. So far, actively driven fans consuming power and generating noise are used in this case. Here we propose a passive adaptive system allowing for convection-driven cooling. The developed system is a highly adaptive flat valve derived from the bordered pit. It was developed through an iterative design process including simulations, both structural and thermodynamic. In hardwoods and conifers, bordered pits enable the challenging transport of vertical fluids by locally limiting damage. Depending on the structure, these can close at sudden pressure changes and take the function of valves. The result of the biomimetic abstraction process is a system-integrative, low-profile valve that is cheap to produce, long-lasting, lightweight, maintenance-free, and noise-free. It allows for the passive switching of air flow generation at the heat exchanger of the cooling between natural convection or an active airstream without the need for complex sensing and control systems. The geometric and material design factors allow for the simple tuning of the valve to the desired switching conditions during the design process. Full article

The effects of periodic hot-press drying on drying behavior and mechanical damage to Chinese fir lumber were investigated by taking the heating platens’ temperature (T_P) and compression ratio (R_c) as experimental factors. The temperature and pressure inside lumber were analyzed during drying process. The results were as follows. The drying rate of lumber was significantly increased with increasing T_P and R_c. Scanning electron microscope (SEM) micrographs showed that bordered pit membranes, cross-field pits, middle lamella between adjacent cells, and tracheid walls were damaged after drying, and the damage became more severe with higher T_P and R_c. Detachments between ray parenchyma cells and tracheids were observed at 170 °C. Nitrogen-adsorption measurement results demonstrated that more cell wall pores in the 2.5~6.2 nm pore diameter range were generated at higher T_P, resulting in an enlarged specific surface area and pore volume of cell walls. These structural changes contributed to accelerating moisture migration and decreasing the drying time. Furthermore, fluctuating pressure inside lumber was the main driving force leading to moisture migration and cell tissue damage in lumber during drying. The influence of T_P on internal temperature (T_M) and pressure (P_M) was greater than R_c. With the increase in T_P from 130 to 170 °C at the R_c of 10%, the maximum T_M and P_M were increased by 30.90% and 39.84%, respectively. However, T_P should not be too high to prevent the formation of macro-cracks caused by high pressure, which may significantly affect wood’s mechanical properties. These results provide theoretical support for periodic hot-press drying processes’ improvement and high-value utilization of Chinese fir. Full article

The nonlinear pressure–flux relationship in the xylem of a conifer is attributed to the fluid–solid interaction within the bordered pits. However, the fluid–solid interactions between the torus–margo structure and the water flow within the pit lack comprehensive understanding. Herein, a fluid–solid interaction model was developed including the deformation of the torus–margo and the flow of water transportation. Nine pit samples were reconstructed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) pictures. Fluid–solid coupling models for pits in the stems of oriental arborvitae (Platycladus orientalis) were developed. The deflection of the torus was roughly proportional to the pressure difference between adjacent tracheids, while the pit resistance exhibited a considerable nonlinear increase. From 250 to 1750 Pa, the pit resistance increased from 4.1466 × 10¹⁶ Pa·s/m³ to 8.8344 × 10¹⁶ Pa·s/m³. The pit resistance decreased, and the pit’s ability to regulate water flow enhanced when the pit diameter increased. Both the pit resistance and the pit’s ability to regulate water decreased when the pit depth increased. The decrease in Young’s modulus for the margo promoted the nonlinear pressure–flux relationship in bordered pits. The findings provide theoretical evidence for the nonlinear relationship between pressure and flux in bordered pits, as well as for the prevention of gas bubble transit through a bordered pit during tracheid cavitation. The passive hydraulic regulation of bordered pits could increase flow resistance and reduce the water flow rate in the xylem, inhibiting tree transpiration. Full article

Bordered pits in conifers have been recognized as a significant evolutionary characteristic that served to impede the spread of embolisms between tracheids. Nevertheless, there was a lack of comprehensive understanding regarding the mechanical properties of the torus and the pit border in relation to the formation of contact seals in aspirated pits. A solid mechanics model was developed to study aspirated bordered pits, incorporating the elastic deformation of the torus–margo structure and the contact behavior between the torus and the pit border. Ten pit samples were reconstructed using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) pictures in order to develop mechanical models for pits in the stems of Platycladus orientalis. Due to the limited contact area on the torus surface, the contact pressure between the torus and the pit border exceeded the air pressure in aspirated bordered pits. The external force and the duration required to seal pits decreased when the pit diameter increased and the pit depth decreased. The augmentation of the torus and margo mass necessitated a lengthier duration for the closure of cavities. The findings presented in this study offered theoretical support for the capillary-seeding hypothesis. The aspiration in bordered pits mechanically depended on the structural and material characteristics of the torus and margo. Full article

Forests are vital ecosystems that are increasingly threatened by environmental stress; exploring the possible trade-off between hydraulic safety and efficiency in plant xylem is crucial to understanding their environmental adaptation strategies. However, to date, there is no consensus whether such trade-offs exist among and within species. To better comprehend the mechanism of xylem water transport, in this review, we summarized previously published work on xylem hydraulic safety and efficiency trade-off from the inter-species, intra-species, and intra-tree perspectives and its influencing factors. We gathered data on xylem hydraulic safety and efficiency and their related anatomical traits, i.e., conduit diameter and inter-conduit pit membrane thickness, from a total of 653 plant species analyzed in 80 published papers. At the inter-species level, we confirmed that there is a weak hydraulic safety and efficiency trade-off. For gymnosperms and herbaceous species, the observed trade-off is stronger. At the intra-species level, the hydraulic safety and efficiency trade-off was found in individuals of the same species investigated in the literature. At the intra-tree level, there is a trade-off between hydraulic safety and efficiency for leaves, stems, and roots, and we confirmed the vessel widening hypothesis, i.e., vessel diameter in the outer wood increases from the top to the bottom of the tree. Additionally, pit membrane thickness increases as the tree height decreases, thus increasing the xylem hydraulic efficiency and affecting the trade-off. Finally, we discussed the environmental factors affecting the trade-off between hydraulic safety and efficiency in the xylem, such as plant habitats, temperature, rainfall, altitude, and soil. Further investigations of the bordered pit membrane from the three-dimensional perspective would be useful to understand the hydraulic safety and efficiency trade-off at the nanoscale. Full article

A hybrid material of polystyrene (PS)–ZrO₂ was developed by the sol–gel technique and deposited by spin-coating on AM60 and AM60–AlN nanocomposite surfaces to enhance corrosion resistance in marine environments.${\text{PS–ZrO}}_2$ with an average thickness of ≈$305 \pm 20 \mathrm{nm}$ was dispersed homogeneously, presenting isolated micro–nano-structure defects with air trapped inside, which led to an increase in roughness (≈4 times). The wettability of the coated substrates was close to the hydrophobic border (${\mathsf{\theta }}_{\mathrm{CA}}=90°–94°).$ The coated samples were exposed for 30 days to SME solution, simulating the marine–coastal ambience. The initial pH = 7.94 of the SME shifted to more alkaline pH ≈ 8.54, suggesting the corrosion of the Mg matrix through the coating defects. In the meantime, the release of ${\mathrm{Mg}}^{2+}$ from the ${\text{PS–ZrO}}_2$-coated alloy surfaces was reduced by ≈90% compared to that of non-coated. Localized pitting attacks occurred in the vicinity of Al–Mn and β–Mg₁₇Al₁₂ cathodic particles characteristic of the Mg matrix. The depth of penetration (≈23 µm) was reduced by ≈85% compared to that of non-coated substrates. The protective effect against Cl ions, attributed to the hybrid PS–ZrO₂-coated AM60 and AM60–AlN surfaces, was confirmed by the increase in their polarization resistance (Rp) in 37% and 22%, respectively, calculated from EIS data. Full article

In the surface mining of mineral deposits, land resources suitable for agricultural purposes are inappropriately spent in large volumes. When mining deep open pits, overburden rocks are mainly transported to the surface. The optimal solution for reducing the area of disturbed lands is the placement of overburden rocks in internal dumps in the open pit. This is especially suitable when mining a mineral deposit with several open pits where at least one of them is depleted. Therefore, it is important to assess the feasibility of building an internal dump, based on the stability parameters of its slopes and the safe distance for placing mining equipment within its boundaries, which was the focus of this research. Numerical modeling with Slide 5.0 software was used to determine the stability of the dump slope inside the open pit and the safe distance from the upper slope edge for placing mining equipment. This reflected the geomechanical situation occurring within the boundaries of the dump formed in the open-pit field with a high degree of reliability. It was determined that the maximum standard safety factor values of the open-pit slopes are within the limits when the overburden rocks border on the hard bedrock (Ks.s.f ≥ 1.2). Under the condition where the dump slope bordered on sedimentations represented by clays, loams, and sands with a strength of 2–3 on the Mohs scale, the safety factor decreased by 22%. It was determined that the minimum safe distance from the outer contour of the dragline base to the upper edge of a single-tier dump was 15.5 m with a safety factor of 1.21. The maximum safe distance values in the range of 73.5–93 m were concentrated within the boundaries of sections 5–9, with a safety factor from 1.18 to 1.28. When the dragline was located within the boundaries of section 7, the dump construction works should be conducted only if the dump exist for up to 3 years. Based on the identified parameters, on the example of using the ESH-11/70 walking dragline, a technological scheme of its operation was developed with the allocation of safe boundaries for its placement when forming an internal dump. The results obtained are useful for the development of projects for the reclamation of depleted open pits. Full article

We previously demonstrated that mice with targeted deletion of the leucine repeat rich kinase 1 (Lrrk1) gene were osteopetrotic due to the failure of osteoclasts to resorb bone. To determine how LRRK1 regulates osteoclast activity, we examined the intracellular and extracellular acidification with an acidotropic probe, acridine orange, in live osteoclasts on bone slices. We examined lysosome distribution in osteoclasts by localization of LAMP-2, cathepsin K, and v-ATPase by immunofluorescent staining with specific antibodies. We found that both vertical and horizontal cross-sectional images of the wild-type (WT) osteoclasts showed orange-staining of the intracellular acidic vacuoles/lysosomes dispersed to the ruffled border. By contrast, the LRRK1 deficient osteoclasts exhibited fluorescent orange staining in the cytoplasm away from the extracellular lacunae because of an altered distribution of the acidic vacuoles/lysosomes. In addition, WT osteoclasts displayed a peripheral distribution of LAMP-2 positive lysosomes with a typical actin ring. The clustered F-actin constitutes a peripheral sealing zone and a ruffled border which was stretched out into a resorption pit. The LAMP-2 positive lysosomes were also distributed to the sealing zone, and the cell was associated with a resorption pit. By contrast, LRRK1-deficient osteoclasts showed diffused F-actin throughout the cytoplasm. The sealing zone was weak and not associated with a resorption pit. LAMP-2 positive lysosomes were also diffuse in the cytoplasm and were not distributed to the ruffled border. Although the LRRK1-deficient osteoclast expressed normal levels of cathepsin K and v-ATPase, the lysosomal-associated cathepsin K and v-ATPase were not accumulated at the ruffled border in Lrrk1 KO osteoclasts. Our data indicate that LRRK1 controls osteoclast activity by regulating lysosomal distribution, acid secretion, and protease exocytosis. Full article

Tingia Halle, a representative genus of the Cathaysia Flora, has been studied for nearly 100 years, being a small heterosporous tree based on the gross morphology of Tingia unita. However, the systematic affinity of Tingia is uncertain. Now, a number of well-preserved fossils of T. unita from the Taiyuan Formation of Lower Permian in Wuda Coalfield, Wuhai City, Inner Mongolia facilitates an examination of wood anatomy. The stem anatomy of T. unita shows parenchymatous pith, endarch primary xylem, pycnoxylic secondary xylem, and cortex, typically a type of gymnosperm wood, which taken together with pteridophytic reproduction, certainly evidences that Tingia Halle is a progymnosperm. In addition, Tingia together with Paratingia provide strong evidence to link the Noeggerathiales with progymnosperms. Full article

Mining regions in different parts of the world have been associated with the significant pollution of water, sediments, and soils by manganese and other chemical elements. This study assessed the degree of geochemical transformation caused by open-pit extraction and processing of mineral resources in the Kovdorsky District of Murmansk Oblast, 20 km from the Russia–Finland border. A second objective was to predict further changes co-driven by industrial pressure and high climatic instability in the polar region. The field study involved sampling water and sediments from virgin background streams and from the tailings storage facility, settling ponds, rivers, and lakes affected by ore mining and disintegration. Laboratory analyses included the study of elemental composition, redox potential, alkalinity and acidity, organic matter content, and other geochemical characteristics for a better understanding of pollutant migration patterns. We revealed elevated levels of potentially toxic elements in surface waters and bottom sediments which pose a risk to the human health via the household and drinking water supply. Pollution with manganese (Mn) was found to be the major environmental issue. Its natural presence in the river water was overridden a hundredfold by anthropogenic enrichment. This is problematic as Mn is easily bioaccumulated, which can lead to unwanted ecotoxicological effects, and—in the case of prolonged exposure to high doses of Mn and its compounds—to detrimental human health impacts. We believe that the changing climate may raise the water flow and thus expand the area of the hydrochemical anomaly. On the other hand, the activation of self-purification and dilution processes could lead to decreasing environmental Mn concentrations. Full article