Search Results (346)

Soft soils, characterized by high compressibility, low shear strength, and high water sensitivity, pose serious challenges to geotechnical engineering in infrastructure projects. Traditional stabilization methods such as lime and cement face limitations, including environmental concerns and poor durability under chemical or cyclic loading. Ionic soil stabilizers (ISSs), which operate through electrochemical mechanisms, offer a promising alternative. However, their long-term performance—particularly under environmental stressors such as acid/alkali exposure and cyclic wetting–drying—remains insufficiently explored. This study evaluates the strength and durability of ISS-modified soil through a comprehensive experimental program, including direct shear tests, permeability tests, and cyclic wetting–drying experiments under neutral, acidic (pH = 4), and alkaline (pH = 10) environments. The results demonstrate that ISS treatment increases soil cohesion by up to 75.24% and internal friction angle by 9.50%, particularly under lower moisture conditions (24%). Permeability decreased by 88.4% following stabilization, resulting in only a 10–15% strength loss after water infiltration, compared to 40–50% in untreated soils. Under three cycles of wetting–drying, ISS-treated soils retained high shear strength, especially under acidic conditions, where degradation was minimal. In contrast, alkaline conditions caused a cohesion reduction of approximately 26.53%. These findings confirm the efficacy of ISSs in significantly improving both the mechanical performance and environmental durability of soft soils, offering a sustainable and effective solution for soil stabilization in chemically aggressive environments. Full article

The rapid growth of plant-based biodegradable tableware, driven by plastic restrictions, necessitates rigorous safety assessments of potential chemical contaminants like per- and polyfluoroalkyl substances (PFASs). This study comprehensively evaluated PFAS contamination risks in commercial sugarcane pulp tableware, focusing on the residues of five target PFASs (PFOA, PFOS, PFNA, PFHxA, PFPeA) and their migration behavior under simulated use and takeout conditions. An analysis of 22 samples revealed elevated levels of total fluorine (TF: 33.7–163.6 mg/kg) exceeding the EU limit (50 mg/kg) in 31% of products. While sporadic PFOA residues surpassed the EU single compound limit (0.025 mg/kg) in 9% of samples (16.1–25.5 μg/kg), the levels of extractable organic fluorine (EOF: 4.9–17.4 mg/kg) and the low EOF/TF ratio (3.19–10.4%) indicated inorganic fluorides as the primary TF source. Critically, the migration of all target PFASs into food simulants (water, 4% acetic acid, 50% ethanol, 95% ethanol) under standardized use conditions was minimal (PFOA: 0.52–0.70 μg/kg; PFPeA: 0.54–0.63 μg/kg; others < LOQ). Even under aggressive simulated takeout scenarios (50 °C oscillation for 12 h + 12 h storage at 25 °C), PFOA migration reached only 0.99 ± 0.01 μg/kg in 95% ethanol. All migrated levels were substantially (>15-fold) below typical safety thresholds (e.g., 0.01 mg/kg). These findings demonstrate that, despite concerning residue levels in some products pointing to manufacturing contamination sources, migration during typical and even extended use scenarios poses negligible immediate consumer risk. This study underscores the need for stricter quality control targeting PFOA and inorganic fluoride inputs in sugarcane pulp tableware production. Full article

Despite the availability of various materials for chimney applications, ongoing research seeks alternatives with improved thermal and chemical resistance. Geopolymers are a promising solution, exhibiting exceptional resistance to high temperatures, fire, and aggressive chemicals. This study investigates fly ash-based lightweight geopolymer concretes that incorporate expanded clay aggregate (E.C.A.), perlite (P), and foamed geopolymer aggregate (F.G.A.). The composites were designed to ensure a density below 1200 kg/m³, reducing overall weight while maintaining necessary performance. Aggregate content ranged from 60 to 75 wt.%. Physical (density, thickness, water absorption), mechanical (flexural and compressive strength), and thermal (conductivity, resistance) properties were evaluated. F.G.A. 60 achieved a 76.8% reduction in thermal conductivity (0.1708 vs. 0.7366 W/(m·K)) and a 140.4% increase in thermal resistance (0.1642 vs. 0.0683). The F.G.A./E.C.A./P 60 mixture showed the highest compressive strength (18.069 MPa), reaching 52.7% of the reference concrete’s strength, with a 32.3% lower density (1173.3 vs. 1735.0 kg/m³). Water absorption ranged from 4.9% (REF.) to 7.3% (F.G.A. 60). All samples, except F.G.A. 70 and F.G.A. 75, endured heating up to 800 °C. The F.G.A./E.C.A./P 60 composite demonstrated well-balanced performance: low thermal conductivity (0.2052 W/(m·K)), thermal resistance up to 1000 °C, flexural strength of 4.386 MPa, and compressive strength of 18.069 MPa. The results confirm that well-designed geopolymer lightweight concretes are suitable for chimney and flue pipe linings operating between 500 and 1000 °C and exposed to acidic condensates and aggressive chemicals. This study marks the initial phase of a broader project on geopolymer-based prefabricated chimney systems. Full article

Water ingress and penetration of aggressive fluids undermines the integrity of many concrete structures. For this reason, optimal performance of such structures up to their designed life cannot be guaranteed. This study introduces nano silicon as an alternative waterproofing admixture for increasing life span of cementitious materials, due to its non-vulnerability to deterioration, which is common to traditional surface coating solutions. Therefore, nano silicon was characterized using Field Emission Scanning Electron Microscope (FESEM), Energy Dispersion Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and surface Zeta potential. The Central Composite Design (CCD) tool was adopted to plan the experiment and further used to model the relationship between experimental variables and experimental response. The model was found to be nonlinear quadratic based on Analysis of Variance (ANOVA). Also, the validity of the model was evaluated and found to have accurate prediction with mean absolute percentage error (MAPE) of 1.62%. The optimum mix ratio necessary to increase resistance to capillary water absorption was established at a nano silicon dosage of 6.6% by weight of cement and w/c of 0.42. In conclusion, the overall results indicate that resistance to capillary water absorption was increased by 62%. Furthermore, while gas permeability was reduced by 31%, on the other hand, volume of water permeable voids decreased by 10%. Full article

Sustainable architectural heritage conservation focuses on preserving historical buildings while promoting environmental sustainability. It involves using eco-friendly materials and methods to ensure that the cultural value of these structures is maintained while minimizing their ecological impact. In this paper, the use of the hydroxyapatite (HAp) in various combinations on masonry samples is presented, with the aim of identifying the ideal solution to be applied to an entire historical building in Banloc monument. The new solution has various advantages: compatibility with historical lime mortars (chemical and physical), increased durability under aggressive environmental conditions, non-invasive and reversible, aligning with conservation ethics, bioinspired material that avoids harmful synthetic additives, preservation of esthetics—minimal visual change to treated surfaces, and nanostructural (determined via SEM and AFM) reinforcement to improve cohesion without altering the porosity. An innovative approach involving hydroxiapatite addition to commercial mortars is developed and presented within this paper. Physico-chemical, mechanical studies, and architectural and economic trends will be addressed in this paper. Some specific tests (reduced water absorption, increased adhesion, high mechanical strength, unchanged chromatic aspect, high contact angle, not dangerous freeze–thaw test, reduced carbonation test), will be presented to evidence the capability of hydroxyapatite to be incorporated into green renovation efforts, strengthen the consolidation layer, and focus on its potential uses as an eco-material in building construction and renovation. The methodology employed in evaluating the comparative performance of hydroxyapatite (HAp)-modified mortar versus standard Baumit MPI25 mortar includes a standard error (SE) analysis computed column-wise across performance indicators. To further substantiate the claim of “optimal performance” at 20% HAp addition, independent samples t-tests were performed. The results of the independent samples t-tests were applied to three performance and cost indicators: Application Cost, Annualized Cost, and Efficiency-Cost-Performance (ECP) Index. This validates the claim that HAp-modified mortar offers superior overall performance when considering efficiency, cost, and durability combined. Full article

Urothelial carcinoma (UC) is a common genitourinary malignancy. Smoking, exposure to arsenic in drinking water, and age can increase the risk of developing UC. Neoadjuvant cisplatin-based chemotherapy prior to radical cystectomy is the standard treatment for the muscle invasive form of UC (MIUC). Tumors of the basal/squamous (Ba/Sq) subtype of MIUC are aggressive, express basal keratins (KRT5, 6, and 14), are associated with squamous differentiation (SD), and frequently develop chemotherapy resistance. The SOX2 transcription factor is a marker of UC stem cells, and its expression is associated with poor overall and disease-free survival. We hypothesized that the attenuation of SOX2 would reduce the expression of basal keratins and increase the chemotherapy response in human UC cells. For this study, we performed lentiviral knockdown (KD) of SOX2 expression in two separate arsenite (As³⁺)-transformed UROtsa (As_I, As_II), 5637, and RT4 cells. Cellular growth and colony-forming ability was inhibited in all UC cell lines after SOX2 KD. We demonstrate that SOX2 KD in the UC cells of the Ba/Sq subtype (As_I, As_II, 5637) decreased the expression of stem-associated proteins, oncoproteins, and basal keratins. Additionally, there was an induction of several luminal markers and enhanced cisplatin sensitivity following the repression of SOX2. Lastly, proteomics revealed reductions in lipid-, cholesterol-, and interferon-signaling pathways after SOX2 KD. This study provides a better understanding of the regulation of key genes responsible for defining the Ba/Sq subtype of UC and demonstrates that the inhibition of SOX2 improves chemotherapy response in UC. Full article

Additive manufacturing (AM), particularly fused deposition modeling (FDM) 3D printing, has emerged as a versatile and accessible technology for prototyping and functional part production across a wide range of industrial applications. One of the critical performance-limiting factors in AM is the chemical resistance of thermoplastic materials, which directly influences their structural integrity, durability, and suitability in chemically aggressive environments. This study systematically investigates the chemical resistance of eight different widely utilized FDM filaments—acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylate (ASA), polyamide (PA, Nylon), polycarbonate (PC), polyethylene terephthalate glycol (PETG), polylactic acid (PLA), polypropylene (PP), and polyvinyl butyral (PVB)—by examining their tensile strength and impact resistance after immersion in representative chemical agents: distilled water, ethanol (99.5%), isopropyl alcohol (75% and 99%), acetic acid (8%), hydrochloric acid (37%), hydrogen peroxide (30%), and acetone (99.5%). Quantitative mechanical testing was conducted in accordance with ASTM D638 and ASTM D256 standards, and statistical variability was accounted for using triplicate measurements with standard deviation analysis. The results reveal that PP exhibits the highest chemical resilience, retaining over 97% of its mechanical properties even after 7 days of immersion in aggressive solvents like acetone. PETG and ASA also demonstrated quite successful stability (>90% retention) in mildly corrosive environments such as alcohols and weak acids. In contrast, PLA, due to its low crystallinity and polar ester backbone, and PVB, due to its high amorphous content, showed substantial degradation: tensile strength losses exceeding 70% and impact resistance dropping below 20% in acetone. Moderate resistance was observed in ABS and PC, which maintained structural properties in neutral or weakly reactive conditions but suffered mechanical deterioration (>50% loss) in solvent-rich media. A strong correlation (r > 0.95) between tensile and impact strength reduction was found for most materials, indicating that chemical attack affects both static and dynamic mechanical performance uniformly. The findings of this study provide a robust framework for selecting appropriate 3D printing materials in applications exposed to solvents, acids, or oxidizing agents. PP is recommended for harsh chemical environments; PETG and ASA are suitable for moderate exposure scenarios, whereas PLA and PVB should be limited to low-risk, esthetic, or disposable applications. Full article

Sustainable waste recycling continues to be one of the most significant challenges in this century, especially for the office paper sector. On top of that, photocatalysis depends on solar radiation as an unlimited and environmentally friendly energy source for removing organic pollutants from contaminated water. The obtaining of AC from office paper waste was carried out with the help of the chemical activation method using ZnCl₂ as an activation agent, followed by heating the samples in adequate conditions. In the present research, we assessed the influence of the amount of ZnCl₂ activator on the properties of AC. In our experimental conditions, a part of ZnCl₂ was transformed into ZnO, deposited onto AC, and formed a composite. We attempted to minimize aggressive chemical agents through inexpensive technical solutions and experimental approaches. The properties of the obtained AC samples were evaluated by XRD, XPS, SEM/EDX, EPR, and surface area and porosity investigations. All of the samples exhibit photocatalytic activity toward Rhodamine B. The photocatalytic mechanism was evaluated considering the existence of reactive oxygen species (ROSs), as evidenced by spin-trapping experiments. Full article

The social stress due to regrouping and hierarchy establishment in cattle in the transition from rangeland to feedlots may cause considerable losses in beef production due to aggressive interactions. This study determined the effect of the premortem social ranks of bovines in the transition from rangelands to fattening pens on beef quality. The behavior of 20 heifers was evaluated in three premortem stages: 72 h after transportation, after 6 weeks of fattening, and while waiting at the slaughterhouse. Heifers were classified as dominant (D) or subordinate (S) based on ethograms. The principal component analysis revealed a strong relationship between social rank and beef color (L*, a*, b*, chroma, HUE, and ΔE), pH, and water holding capacity. The linear discriminant analysis of the beef quality variables classified the animals in one of four social ranks (dominant, change to subordinate, subordinate, change to dominant) with 95% precision. pH 45 (−9.163), drip 0 d (−3.917), final chroma (1.773), and ΔE (1.646) obtained high coefficients that determined the separation among the classes. Color variables like ΔE (p = 0.049) and chroma 0 d (p = 0.053) showed significant differences between the D and S animals in the MANOVA. Reactivity in dominants tended to negatively impact beef quality, affecting its color and pH. These findings contribute to a better understanding of how social dynamics impact beef quality during the transition period. Full article

Salivary gland cancers (SGCs) pose a therapeutic challenge due to their aggressive nature and limited treatment options. Ion transporters, particularly the sodium/iodide symporter (SLC5A5), which transport iodine in the form of iodide anion (I⁻) into cells, have emerged as potential therapeutic targets in tumors of glandular origin. Our research indicates that SLC5A5 is expressed predominantly in ductal cells of human and murine SGC cells. We assessed the effects of potassium iodide (KI), a source of iodide ions. KI treatment reduced SGC cell proliferation and viability without impacting migration. KI increased ROS levels and triggered caspase-dependent apoptosis, as indicated by the upregulation of the pro-apoptotic protein BAX, downregulation of the anti-apoptotic protein Bcl-2, and induction of SGC cell shrinkage. KI did not affect NF-κB or TNF-α and SLC5A5 expression. Adding the antioxidant N-acetylcysteine reversed KI-induced growth inhibition, underscoring ROS-induced oxidative stress’s crucial role in growth inhibition. While KI administered in drinking water to mice increased epidermal growth factor (EGF) expression in non-malignant salivary gland tissues, KI decreased EGF receptor (EGFR) expression in malignant SGC cell cultures, where EGFR signaling is frequently dysregulated in SGCs but promoted AKT phosphorylation. Combining KI and anti-EGFR treatment did not yield synergistic anti-SGC cell effects. The study underscores the therapeutic potential of KI as a standalone treatment in vitro for SGC cells. However, the upregulation of EGF in non-malignant tissues and, therefore, the possibility to enhance EGFR-driven signals and AKT phosphorylation after KI treatment in cancer patients could indicate a risk of rendering SGC cells more drug resistant, warranting further investigation to optimize its clinical application. Full article

Background: Three-dimensional (3D) cell models may bridge the gap between two-dimensional (2D) cell cultures and animal models. Technical advances have led to the development of 3D-bioprinted cell models, characterized by greater reproducibility and the ability to mimic in vivo conditions. Glioblastoma multiforme (GBM) is a highly aggressive brain tumor with poor clinical outcomes due to its heterogeneity, angiogenic activity, and invasiveness. Src family kinases (SFKs) play a crucial role in GBM progression, making them attractive targets for drug development. Here, we show results about the pharmacological profile of a new prodrug synthesized from a Src inhibitor, SI306. Methods: Three-dimensional-bioprinted GBM cell models were used in predicting the antitumor activity of the prodrug SI306-PD2 with respect to its precursor, SI306. Results: Since the prodrug releases the active inhibitor through the cleavage by specific enzymes, SI306-PD2 was analyzed for stability and release kinetics in various media, including fetal bovine serum (FBS), which is normally used in cell culture. In comparison to SI306, SI306-PD2 demonstrated higher solubility in water, higher permeability across gastrointestinal and blood–brain barrier membranes, and the ability to release the drug in the presence of FBS progressively. In the 2D GBM cell model, using U87 and U251 cell lines, both compounds similarly reduced tumor cell viability. In 3D-bioprinted cell models, in the presence of an FBS-free medium, SI306-PD2 exhibited a more effective antitumor activity compared to SI306, reducing the proliferation and diameter of U251 spheroids grown within the bioprinted scaffold in a statistically significant manner. The analysis of proteins extracted from 3D scaffolds confirmed that SI306-PD2 inhibited Src activation more efficiently than SI306. Conclusions: Our study suggests that, when tissue permeability represents a discriminating characteristic, bioprinted cell models can provide a valid alternative for studying the cytotoxicity of new antitumor compounds. This approach has permitted us to ascertain the potential of the prodrug SI306-PD2 as a therapeutic agent for GBM, demonstrating better tissue penetration and antiproliferative efficacy compared to the precursor compound SI306. Full article

Over 2 million tonnes of ceramic waste are generated annually in South Africa, with the majority disposed of in landfills, contributing to environmental degradation. Meanwhile, researchers are actively seeking sustainable alternatives to Portland cement (PC), which is associated with significant environmental challenges. Ceramic waste powder (CWP) refers to finely milled ceramic waste and powder derived from the polishing and finishing stages of ceramic production. This review examines the potential of CWP as a partial replacement for PC in concrete, focusing on its effects on workability, mechanical durability, and microstructural properties. The findings indicate that moderate replacement levels (up to 20%) enhance the compressive and flexural strengths of concrete. However, these benefits are not consistently reported across all studies. Additionally, CWP improves the microstructural properties of the concrete. This is probably due to the pozzolanic reactions of CWP, which result in a denser concrete matrix and enhanced long-term durability. Notable durability benefits include reduced water absorption, increased resistance to chemical attacks, and improved thermal insulation. However, the performance of concrete with higher CWP replacement levels (above 30%) remains unclear. Some studies have reported strength reductions and increased susceptibility to durability loss at this level. Further studies should focus on clarifying its pozzolanic reactivity, durability in aggressive environments, and optimum replacement percentage. Full article

The durability of reinforced concrete structures in aggressive environments is strongly influenced by the ingress of chloride and other harmful ions, which is further complicated under partially saturated conditions, due to the coexistence of liquid and gas phases within the pore network. This study aimed to develop a predictive moisture–chemical–temperature model and to elucidate the mechanisms governing ion transport in partially saturated concrete. A multi-species hygro-chemo-thermo transport model was formulated based on the Nernst–Planck equation, incorporating electroneutrality, zero current conditions, and the coupled effects of moisture and temperature gradients. The model was numerically implemented using a parallel FE method with the Crank–Nicolson scheme, supported by domain decomposition and SPMD techniques for high computational efficiency. As a result, experimental validation was performed through chloride ponding tests under varying temperature conditions (20 °C, 35 °C, 50 °C), water-to-cement ratios (0.55, 0.65), and relative humidity differences (100%, 60%). The simulation results showed good agreement with the experimental data and confirmed that the proposed model can effectively predict chloride penetration under both isothermal and non-isothermal conditions. Additionally, the simulations revealed that moisture gradients accelerate ion transport, as the inward migration of the moisture front enhances the diffusion rates of chloride, sodium, and calcium ions until a steady-state moisture distribution is reached. Full article

During the past quarter-century, the natural populations of giant honey bees (Apis dorsata) have declined markedly. The loss of nesting sources is one of the many reasons for its decline. This has threatened the pollination services of several agricultural and wild plants in areas of its natural habitat. To sustain pollination services in the natural habitat of this honey bee, conservation efforts are crucial. For this purpose, 1 m-long, 15 cm-wide, and 0.5 m-deep wooden nesting planks were designed and prepared. The latter were hung on the eaves/projections of university buildings to attract the migratory swarms of this honey bee. The occupancy of these planks confirmed that the bees accepted them as nesting sites. The experimental trial was conducted with four treatments, each replicated four times over a period of 10 years. This honey bee accepted, occupied, and nested on only those wooden planks that were treated with molten beeswax or contained traces of beeswax and were tightly fixed to the surface of the eaves/building projections. The occupation and re-occupation indices revealed that this honey bee had strong site preferences. Spraying water on live colonies was the most effective method for safely handling this honey bee, while smoking was slightly less effective. Frequently disturbed colonies showed less aggressiveness than the undisturbed colonies. This study aids in the domestication, handling, and conservation of this honey bee in its natural habitat, where the continuous removal of nesting sources threatens the sustainability of pollination services. Full article

One of the most problematic situations for the estimated 60 million working donkeys and mules across the world is within the brick kiln environment. In countries such as Egypt, Nepal, India and Pakistan, donkeys and mules carry dried bricks into small kilns either by pulling carts or carrying loaded packs. The health and welfare problems of this environment are well documented: they may carry excessive loads; work long hours, have difficulties accessing food, water and rest options; and can frequently suffer untreated illnesses including dental problems, lameness and open wounds from poorly fitting harnesses and aggressive handlers. The impact of this environment on their mental health has been largely overlooked. We use a behavioral comparative analogy approach, comparing the clinical signs and risk factors associated with learned helplessness, depression and complex post-traumatic stress disorder (cPTSD) in humans and laboratory studies in other animals with evidence from the veterinary literature. Based on an analysis of seven quantitative veterinary studies that have evaluated the health and behavior of kiln donkeys and mules, we argue that their behavior may be consistent with learned helplessness, depression and/or cPTSD. Furthermore, the kiln environment contains many of the key environmental risk factors associated with the development of these disorders. And, because of certain behavioral differences from horses, donkeys and mules are at greater risk of their physical and mental health being overlooked. This finding, adding to the wealth of evidence for their poor health, should further strengthen efforts to replace their use in the kiln environment. Full article