Search Results (6)

Airborne particulate matter (PM) is one of the most urgent urban environment problems in the world today. The urban ecosystem has been identified as a potentially promising solution to reduce the airborne PM based on the ability of plants to retain PM. Numerous studies have been conducted to explore the process and mechanism of atmospheric PM retention by plant leaves in the past. In this study, in order to better summarize previous research, particularly the impact of leaf traits on PM retention, and to provide guidance for the selection of tree species for nature-based urban PM solutions, a systematic review was carried out using the method recommended in the PRISMA, and a total of 49 articles were selected. It was found that: 1. Asian countries contribute the majority of the proportion (32, 65%). Following behind are European countries (13, 26.5%). The American countries contribute two cases. 2. Among all the tree species, Ginkgo biloba (16), Euonymus japonicus (11), Magnolia denudate (9), Styphnolobium japonicum (9), Magnolia grandiflora (8), and Prunus cerasifera (8) emerged as hot species in research. 3. Leaf area and shape emerged as the two most frequently discussed macro-indicators, while roughness, hairiness, and stomatal characteristics were the top three micro-indicators explored. 4. Roughness and stomata, respectively, play crucial roles in capturing larger PM particles and retaining fine and ultrafine PM through their recessed structures. Trichomes decrease the likelihood of particle resuspension and boosts the efficiency of PM retention. 5. Leaves with high rigidity and complex multi-faceted leaf shapes are typically presumed to exhibit higher PM retention efficiency for higher edge effects and increased interleaf turbulence. Furthermore, with rigidity and edge effects ensured, a larger leaf area is beneficial for retaining PM. Full article

Lyophilized plant-origin extracts are rich in highly potent antioxidant polyphenols. In order to incorporate them into food products, it is necessary to protect these phytochemicals from atmospheric factors such as heat, light, moisture, or pH, and to enhance their bioavailability due to their low solubility. To address these challenges, recent studies have focused on the development of encapsulation techniques for antioxidant compounds within polymeric structures. In this study, lyophilized olive leaf extracts were microencapsulated with the aim of overcoming the aforementioned challenges. The method used for the preparation of the studied microparticles involves external ionic gelation carried out within a water–oil (W/O) emulsion at room temperature. HPLC analysis demonstrates a high content of polyphenols, with 90% of the bioactive compounds encapsulated. Meanwhile, quantification by inductively coupled plasma optical emission spectroscopy (ICP-OES) reveals that the dried leaves, lyophilized extract, and microencapsulated form contain satisfactory levels of macro- and micro-minerals (calcium, potassium, sodium). The microencapsulation technique could be a novel strategy to harness the polyphenols and minerals of olive leaves, thus enriching food products and leveraging the antioxidant properties of the polyphenolic compounds found in the lyophilized extract. Full article

Inspired by the macro- and microstructures of the lotus leaf, a series of biomimetic hierarchical thin-walled structures (BHTSs) was proposed and fabricated, exhibiting improved mechanical properties. The comprehensive mechanical properties of the BHTSs were evaluated using finite element (FE) models constructed in ANSYS, which were validated by the experimental results. Light-weight numbers (LWNs) were used as an index to assess these properties. The simulation results were compared with the experimental data to validate the findings. The compression results indicated that the maximum load carried by each BHTS was very similar, with the highest bearing load being 32,571 N and the lowest being 30,183 N, resulting in only a 7.9% difference between them. In terms of the LWN-C values, the BHTS-1 exhibited the highest value at 318.51 N/g, while the BHTS-6 had the lowest value at 295.16 N/g. For the torsion and bending results, these findings suggested that increasing the bifurcation structure at the end side of the thin tube branch significantly improved the torsional resistance properties of the thin tube. For the impact characteristics of the proposed BHTSs, enhancing the bifurcation structure at the end of the thin tube branch significantly increased the energy absorption capacity and improved the energy absorption (EA) and the specific energy absorption (SEA) values of the thin tube. The BHTS-6 had the best structural design in terms of both the EA and SEA among all the BHTSs, but its CLE value was slightly lower than that of the BHTS-7, indicating slightly lower structural efficiency. This study provides a new idea and method for developing new lightweight and high-strength materials as well as designing more effective energy absorption structures. At the same time, this study has important scientific value in understanding how biological structures in nature exhibit their unique mechanical properties. Full article

Dynamic particulate matter (PM) behavior on leaves depends on rainfall events, leaf structural and physical properties, and individual tree crowns in urban forests. To address this dependency, we compared the observed relationships between PM wash-off ability and leaf traits on inner and outer crown-positioned leaves during rainfall events. Data showed significant differences in the PM wash-off ability between inner and outer crown-positioned leaves relative to rainfall events due to leaf macro- and micro-structure and geometric properties among tree species. Our results showed that PM wash-off effects on leaf surfaces were negatively associated with trichome density and size of leaf micro-scale during rainfall events. Specifically, Quercus acutissima with dense trichomes and micro-level surface roughness with narrow grooves on leaf surfaces showed lower total PM wash-off in both inner (−38%) and outer (105%) crowns during rainfall. Thus, their rough leaves in the inner crown might newly capture and/or retain more PM than smooth leaves even under rainfall conditions. More importantly, Euonymus japonicus, with a thin film-like wax coverage without trichome, led to higher total PM wash-off in both inner (368%) and outer (629%) crowns during rainfall. Furthermore, we studied the changes in PM wash-off during rainfall events by comparing particle size fractions, revealing a very significant association with macro-scale, micro-scale, and geometric features. Full article

Commiphora species are of high medicinal importance. They are distributed in Saudi Arabia, mainly in rocky habitats and regions under mountains, including the east of Tihama, forming a distinct element of Saudi flora. The present study focuses on the botanical characterization of five species of Commiphora, i.e., C. erythraea, C. gileadensis, C. kataf, C. myrrha, and C. quadricincta. The morphological characters for each species were recorded comparatively, and their taxonomic relationships were examined using gross morphology by generating a UPGMA dendrogram, which separated the Commiphora species into two distinct groups. A dichotomous key was generated to facilitate the identification process of the plant, even by naked eye, by obvious characteristics. Because of the similarities in anatomical structure of the stem and petiole of most studied species, only the quantitative variations are illustrated comparatively. Seed macro- and micro-morphological characteristics were recorded comparatively to be used in the identification of a species in the case of leaf absence. The phytochemical study included measurements of total phenolic and flavonoid contents. The phytochemical results were correlated with the ethno-botanic survey. The traditional uses for all species were recorded using the questionnaire and open interviews method for data collecting. The results revealed that the most common Commiphora species that are traditionally used are C. myrrha and C. gileadensis. The study recommends more research on Commiphora species using more advanced techniques and tries to increase public awareness on the importance of these plants. Full article

Moso bamboo (Phyllostachys edulis (Carriere) J. Houzeau), native to China, is one of the most economically and ecologically important bamboo species. Since the economic interests and the strong clonality, it has been widely cultivated in southern China, which inevitably reduces the natural stands and leads to gene loss in this species. In this study, three natural populations of Moso bamboo distributed in Anhui, Guangxi, and Zhejiang province, were used to analyze the correlation between phenotypic traits, cell structure, and material properties from the perspective of phenotypic, genetic, and environmental. Among those traits and properties, fiber width was correlated with wall thickness at breast height and average nodes length under branch positively. Leaf length was correlated positively with fiber lumen diameter and parenchyma lumen diameter. Furthermore, it showed a very close correlation between moisture content, bending strength, modulus of elasticity, and diameter at breast height, clear height, and leaf length. The lumen diameter of fiber cell wall thickness is positively correlated with bending strength and modulus of elasticity. Density is positively correlated with parenchyma cell wall thickness. The experimental design is relatively detailed and representative, and the workload is huge. This study reflects the research objectives with scientific and rational experiments and data. This study will analyze the differences of various indicators from the perspective of genetic to build a bridge between micro-structure and macro-structure for rational utilization of the whole area of Moso bamboo resources in China. Full article