Biological soil crusts (BSCs; biocrusts) are well developed in drylands, which are crucial to the stability and resilience of dryland ecosystems. In the southeastern Gurbantunggut Desert, a typical sandy desert in the middle part of central Asia, engineering development has an increasing negative impact on ecosystems. Fortunately, ecological restoration measures are being implemented, but the exact effect on soil quality is still unclear. In artificial sand-fixing sites on reshaped dunes along the west-east desert road, a total of 80 quadrats (1 m x 1 m) of reed checkerboards after the implementation of sand-fixing measures for 10 years were investigated to determine the BSC development status and soil properties. The algal and lichen crusts accounted for 48.75 % and 26.25 % of the total quadrat number, respectively, indicating an obvious recovery effect of BSC (only 25 % for bare sand). The developmental level of BSC gradually increased from the top to the bottom of the dunes (Li 0 -> Li 6),which was consistent with the distribution pattern of BSCs on natural dunes. Compared with bare sand, the soil organic carbon (13.85 % and 23.07 % increases), total nitrogen (12.55 % and 23.95 % increases), total potassium (9.30 % and 8.24 % increases), and available nitrogen (23.97 % and 61.41 % increases) contents of algal and lichen crusts were significantly increased, and lichen crusts had markedly higher increase effect than algal crusts. The BSC development markedly reduced soil pH (0.49 % and 0.50 % decreased) and increased electrical conductivity(11.99 % and 10.68 % increases), resulting in improved soil microenvironment. Soil properties showed significant linear relationships with BSC development level, and an optimal fitting (R2 = 0.770 or 0.780) was detected for the soil fertility index. Based on the soil property matrix, the bare sands, algal, and lichen crusts were markedly separated along the first axis in the PCA biplot, which once again confirmed the significant positive effect of BSC recovery on soil fertility improvement. Consequently, in the early stage of sand-fixation (e.g., < = 10 years) by reed checkerboards on the damaged desert surface, BSC recovery can well promote and predict soil fertility in this area. The results provide a reliable theoretical basis for the restoration technology and scientific management of degraded sandy desert ecosystems.
This study investigated the impact of optimum dosages of nano-calcium carbonate (nano-CaCO3) and nanosilica on the engineering behavior of black cotton soil. The desired percentage of nano-addition, 2%, for both nanomaterials, was determined by analyzing the plasticity-compaction characteristics and the relative strength index values of treated samples. The study unveiled that the entire clay microstructure was transformed into a nanocrystalline matrix after treatment. The deviatoric strength enhancement with confining pressure and curing period was significant after treating the soil with either nano-CaCO3 or nanosilica. The nanosilica treatment was found to be more effective in improving the California bearing ratio (CBR) strength of black cotton soil samples compared with nano-CaCO3 stabilization. The addition of nanomaterials induced the formation of nanocrystalline hydrate gels and silica gel, resulting in an increased resistance to volumetric deformation under compressive stresses. The hydraulic conductivity of nano-treated samples dropped due to the highly tortuous networks between pores in the nano-crystalline structure. The experimental results were substantiated by analyzing the microstructure of nano-treated soils using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) techniques.
In this study, impact compression tests on low-temperature concrete were conducted using a split Hopkinson pressure bar. The impacts of low temperatures on the strength, fractal, and energy characteristics of concrete were analyzed. The damage evolution mechanism of the microcrack density was discussed based on microscopic damage theory and microscopic tests. The results demonstrated that the impact fractal dimension and energy dissipation density of low-temperature concrete were positively correlated with the strain rate. The strain rate sensitivity of the impact fractal dimension was significantly affected by low temperature at low strain rates; however, low temperature had little effect at high strain rates. The pore water transformed into ice at negative temperatures, the fracture energy of the concrete increased, and the energy dissipation density increased. More than 50 % of the capillary and free water inside the concrete was frozen at -10 degrees C; approximately 30 % of the capillary and free water and 65 % of bound water did not freeze when the temperature was -30 degrees C. The macropores did not collapse under the action of ice filling at high strain rates; however, microcracks were generated around them. With a decreasing temperature, the threshold stress for microcrack propagation increased, crack propagation required more energy, and the microcrack density decreased.
In a world increasingly focused on environmental sustainability and the imperative of efficient waste management, innovative approaches in material science are becoming crucial. This research is centered on the synthesis of cellulose nanocrystals (CNCs) from post-use exam waste paper and the development of a chitosan-CNC (CS-CNCs) composite. CNCs were successfully isolated from waste paper by alkali treatment, bleaching, and sulfuric acid hydrolysis with FTIR and XRD analyses confirming successful extraction and a crystallinity index of 66.3%. TEM imaging revealed CNCs with a unique spherical morphology and diameters of 6-7 nm, significantly smaller than those reported in existing literature. Chitosan (CS), derived from shrimp shell waste, was integrated into the CNCs to form a composite thin film. This film, as revealed by SEM, had a homogeneous and consistent structure. The CS-CNCs composite demonstrated superior mechanical properties, with tensile strength increasing from 17.74 megapascal (MPa) in pure CS film to 22.08 MPa in composite, indicating its potential for robust and sustainable packaging materials. Soil degradation tests over 25 days showed a 24.7% degradation for CS-CNCs films, compared to 9.09% for CS films, underscoring their enhanced biodegradability. The composite exhibited notable antibacterial activity against Escherichia coli, suggesting its suitability for medical and hygiene applications. The measured contact angle of 80.4 degrees indicates the film's hydrophilicity, making it an excellent candidate for self-cleaning surfaces, such as textiles and windows. Remarkably, the CS-CNCs composite demonstrated exceptional photocatalytic degradation of Alizarin Red S dye, achieving 99.7% efficiency in 45 min, far surpassing the 87% efficiency of standalone CS films. The study showcases the green-synthesized CS-CNCs composite from waste paper offering an effective, eco-friendly, and economical approach for wastewater treatment due to its dual capabilities in dye degradation and antibacterial properties, while also opening avenues for its prospective application in self-cleaning surfaces, environmental remediation, and packaging thereby presenting a sustainable and economical solution for environmental cleanup and material innovation.
Land degradation can cause food insecurities and can damage ecosystems. This study highlights the potential of cyanobacteria (Anabaena variabilis, Spirulina platensis, Scytonema javanicum, and Nostoc commune), along with bacteria (Bacillus sp. SSAU-2), and their consortia to form biological soil crust, restoring soil properties and promoting plant growth. The efficiency of soil improvement was characterized by physiochemical parameters such as phosphate solubilization, %TOC, pH, and salinity. Scanning electron microscopy and a pot experiment were utilized to observe the morphological and soil improvement studies. Bacterial inoculation resulted in significant improvements in soil fertility, such as exopolysaccharide, organic carbon, organic matter, phosphorus content, and total soil porosity. Cyanobacteria consortia were more effective than monocultures at improving soil fertility and promoting barley plant development. The potential value of selected cyanobacteria and bacterial consortia as a useful tool for the restoration of degraded land is demonstrated experimentally by this study.
Currently, there is a growing concern for human health with the rise of environmental pollution. Water contamination and health problems had been understood. Sanitation-related health issues have been overcome in the greater part of the world. Progressive industrialization has caused a number of new pollutants in water and in the atmosphere. It is a growing concern for the human health, especially upon the reproductive health. Current researchers provide a strong association between the rising concentrations of ambient pollutants and the adverse health impact. Furthermore, the pollutants have the adverse effects upon reproductive health as well. Major concern is for the health of a pregnant woman and her baby. Maternal-fetal inflammatory response due to the pollutants affects the pregnancy outcome adversely. Preterm labor, fetal growth restriction, intrauterine fetal death, and stillbirths have been observed. Varieties of pathological processes including inflammation, endocrine dysfunction, epigenetic changes, oxidative and nitrosative stress, and placental dysfunction have been explained as the biological plausibility. Prospective studies (systematic review and meta-analysis) have established that exposure to particulate matters (PM) and the nanoparticles (NP) leads to excessive oxidative changes to cause DNA mutations, lipid peroxidation and protein oxidation. Progressive industrialization and emergence of heavy metals, micro- (MP) and nanoparticles (NP) in the atmosphere and in water are the cause for concern. However, most of the information is based on studies from industrialized countries. India needs its own country-based study to have the exact idea and to develop the mechanistic pathways for the control.
The mineralogy and texture of granite have been found to have a pronounced effect on its mechanical behavior. However, the precise manner in which the texture of granite affects the shear behavior of fractures remains enigmatic. In this study, fine-grained granite (FG) and coarse-grained granite (CG) were used to create tensile fractures with surface roughness (i.e. joint roughness coefficient (JRC)) within the range of 5.48-8.34 and 12.68-16.5, respectively. The pre-fractured specimens were then subjected to direct shear tests under normal stresses of 1-30 MPa. The results reveal that shear strengths are smaller and stick-slip behaviors are more intense for FG fractures than for CG fractures, which is attributed to the different conditions of the shear surface constrained by the grain size. The smaller grain size in FG contributes to the smoother fracture surface and lower shear strength. The negative friction rate parameter a - b for both CG and FG fractures and the larger shear stiffness for FG than for CG fractures can account for the more intense stick-slip behaviors in FG fractures. The relative crack density for the post-shear CG fractures is greater than that of the FG fractures under the same normal stress, both of which decrease with the distance away from the shear surface following the power law. Moreover, the damage of CG fracture extends to a larger extent beneath the surface compared with the FG fracture. Our findings demonstrate that the grain size of the host rock exerts a significant influence on the fracture roughness, and thus should be incorporated into the assessment of fault slip behavior to better understand the role of mineralogy and texture in seismic activities. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).
The soil environment has been considered capable of storing toxic substances without serious consequences for the inhabitants since plants are able to bioaccumulate pollutants without compromising their survival. The application of chemicals to increase soil productivity and the dumping of waste have worsened soil quality. Recently, following a greater awareness of the importance of monitoring the damage deriving from the consumption of contaminated crops for humans and of the protection of biodiversity, studies aimed at identifying the effects of soil contamination on terrestrial animals have increased considerably. Studies using field lizards as model organisms fit into this scenario; this research has shed light on the uptake, accumulation, and toxicity of soil pollutants on reptiles. This review summarizes data collected on lizards of the Podarcis genus, a group of resilient wild species capable of living in both pristine and anthropized areas; the data reveal that many of the effects recorded in lizard tissues at the molecular, biochemical, and histological levels are independent of the chemical composition of the contaminants and are mostly linked to the type of cellular response. Overall, these studies confirm Podarcis lizards as a good model system in ecotoxicological and cytotoxicological research, providing an accurate description of the effects of pollutants, clarifying the defense mechanisms activated in relation to different exposure routes and, finally, providing predictive information on the risks faced by other animals. Since the effects recorded in lizards have often also been observed in mammals, it can be concluded that the results obtained from studies on these animals can be translated to other terrestrial vertebrates, including mammals.
Chilled meat is prone to microbial contamination during storage, resulting in a shortened shelf life. This study developed multifunctional biodegradable aerogel with water absorption, antibacterial, and sustained release properties as a preservation pad for meat, using corn straw cellulose nanocrystals (CSCNCs) and acetylated starch (AS) as the structural skeleton and thymol (TMO) nanoemulsions as antimicrobials. The effects of different mass ratios of CSCNCs/AS on the morphology, structure, physical properties, and release behavior of aerogels were systematically analyzed. Additionally, their antibacterial properties, biocompatibility, and biodegradability were investigated. The results showed that the aerogels with CSCNC/AS mass ratio of 1:5 had a tailored structure for loading TMO nanoemulsions, as well as excellent water absorption, mechanical properties, and thermal stability. Due to strong hydrogen bonding and a porous structure, the TMO in the aerogels was continuously and uniformly released into high-water-activity and fatty food simulants, mainly controlled by Fickian diffusion. Furthermore, it exhibited superior antibacterial properties and biocompatibility. The application of aerogels for chilled beef preservation extended the shelf life from 8 days to approximately 12 days, which was superior to commercially available preservation pads. Notably, the aerogels exhibited superior biodegradability in soil. Therefore, the prepared aerogel preservation pads showed great potential in preserving chilled meat.
The impact of global climate change and human-induced nitrogen (N) deposition on winter weather patterns will have consequences for soil N cycling and greenhouse gas emissions in temperate deserts. Biological soil crusts (referred to as biocrusts) are crucial communities in soil and significant sources of nitrous oxide (N2O) emission in desert ecosystems and are sensitive to environmental changes. The contribution of bacteria and fungi to N2O production in drylands has been acknowledged. However, the effect of changes in snow cover and N deposition on the N2O production of different microbial groups of microorganisms is not yet clear. In this study, we examine the responses of fungi and bacteria mediated pathways involved in soil N2O production from biocrusts to longterm snow cover manipulation and N addition experiments in the Gurbantunggut Desert. These soils were incubated and subjected to biocide treatments (such as cycloheximide and streptomycin, and fungal and bacterial inhibitors), after which rates of potential nitrification and N2O production were measured. Compared with controls, snow removal treatments from bare sand, lichen crust and moss crust reduced background rates of N2O production by 29.41 %, 26.21 % and 20.49 %, respectively; N2O production rates were 1.53-fold higher in bare sand, 1.38-fold higher in lichen crust, and 1.56-fold higher in moss crust after N addition. The addition of streptomycin significantly reduced the potential nitrification rates of bare sand and biocrusts, indicating that bacteria may be important sources of NO3- production in biocrusts rather than fungi. Conversely, fungi were main sources of N2O production in biocrusts. Additionally, fungi also played a major role in N2O production in biocrusts after snow cover manipulation and N addition. Both snow cover manipulation and N addition treatment indirectly affected the N2O production in biocrusts by considerably affecting the content of substrate N and the abundance of microbial groups. Our research suggests that fungi are main contributors for denitrification in biocrusts, and that snow cover changes (removal snow and double snow) and N addition alter the contribution of biotic pathways responsible for N cycling.