Search Results (464)

For thousands of years, medicinal plants and their constituents have been used, mostly empirically/ethnopharmacologically, to cure patients with central nervous system (CNS) disorders. Anxiolytics derived from natural products (NPs) often share similar mechanisms of action to synthetic ones (e.g., benzodiazepines, BDZs). Although typically as effective as synthetic anxiolytics, NPs are considered to be devoid of the serious side effects linked to the use of BDZs. 8-Methoxypeucedanin (8-MP) is a rare furanocoumarin present in the fruits of Peucedanum luxurians Tamamsch. (Apiaceae). The primary objective of the presented study was to assess the anxiolytic activity of 8-MP using a zebrafish (Danio rerio) model of anxiety. Danio rerio larvae at 5 days post-fertilization (dpf) were used, with reversed thigmotaxis considered as an index of the anxiolytic activity. In addition to the behavioral study, qPCR analyses were performed to assess the role of 8-MP in modulating the expression of c-fos and bdnf, two key genes involved in neural activity. As evidenced by the behavioral study, 8-MP (1.5–15 µM) exhibited a significant influence on anxiety, with a U-shape dose–response effect. Moreover, the expression of c-fos and bdnf genes was significantly downregulated, providing novel insights into the mechanisms of action of the tested furanocoumarin. Full article

The structural evolution of concrete during different hydration stages critically influences subsequent strength, and continuous monitoring throughout this process has become a research focus in materials science. This study proposes an embedded ultrasonic active sensing technique based on piezoelectric ceramics (PZT) to identify key structural transition stages during concrete curing. To this end, a piezoelectric ultrasonic sensor was fabricated and its comprehensive performance was systematically evaluated. Subsequently, compressive strength and penetration resistance tests were conducted, and the evolution of piezoelectric signal amplitude and wavelet packet energy (WPE) during hydration was analyzed. Furthermore, a root mean square deviation index based on WPE (WPE-RMSD) was introduced to identify structural transitions throughout the hydration process. The results demonstrate that the developed sensor exhibits stable electrical, mechanical, and waterproof performance. Both signal amplitude and WPE effectively captured the hydration process of concrete, with WPE showing higher sensitivity. The WPE-RMSD index exhibited good temporal continuity, covering the entire process from early hydration disturbance to late-stage structural densification (28 d), and proved particularly effective in identifying critical stages such as final setting and the medium-age period (7 d). This study provides a novel in situ monitoring approach for the classification and identification of hydration stages in concrete. Full article

Road and pavement construction require huge volumes of borrowed soils in addition to the foundation soils. Unfortunately, not all soils are suitable for construction purposes. Soil stabilization is a fundamental technique used to enhance the engineering properties of weak ground/soil to meet the demands of large infrastructure projects, such as roads. It is in this regard that this study investigates the strength development, durability, and effectiveness of cement and quarry dust as stabilizers to enhance the geotechnical properties of a weak tropical clay soil. Cement was added in the range of 0% to 10% while quarry dust was used to partially replace soil in the range of 0% to 50%. The results show significant improvements in the Atterberg limits and strength properties of the tropical clay. The liquid limit reduced from 43.2% to 25.1% while the plasticity index reduced from 17.6% to 10.2% at 50% quarry dust and 10% cement content. Similarly, the maximum dry unit weight increased from 17.4 kN/m³ to 21.3 kN/m³ while the optimum moisture content decreased from 17.1% to 12.9%. The maximum soaked CBR value was 172%, representing a 1497% enhancement over untreated soil. Also, the maximum unconfined compressive strength (UCS) reached 2566 kN/m² at 28 days of curing, representing a 1793.73% increase when compared to the untreated soil. Cement content was found to be the predominant factor influencing strength development. The study shows that cement–quarry dust blends compacted at high energy can be adopted in sustainable road construction. Full article

This research evaluates the stabilization of a clay collected from the northern expansion zone of Cartagena de Indias, Colombia. Laboratory analyses, including particle size distribution, Atterberg limits, compaction, specific gravity, and XRF/XRD, classified the soil as a highly plastic clay (CH) with moderate dispersivity, as confirmed by pinhole and crumb tests. The soil was treated with 3–9% lime, with and without the addition of NaCl (0% and 2%), and tested for unconfined compressive strength (q_u), small-strain stiffness (G_o), and microstructural properties under curing periods of 14 and 28 days at two compaction densities. Results showed that lime significantly improved mechanical behavior, while the inclusion of NaCl further enhanced q_u (up to 185%) and G_o (up to 3-fold), particularly at higher lime contents and curing times. Regression models demonstrated that both q_u and G_o follow power-type relationships with the porosity-to-lime index, with consistent exponents (−4.75 and −5.23, respectively) and high coefficients of determination (R² > 0.79). Normalization of the data yielded master curves with R² values above 0.90, confirming the robustness of the porosity-to-lime framework as a predictive tool. The G_o/q_u ratio obtained (3737.4) falls within the range reported for cemented geomaterials, reinforcing its relevance for comparative analysis. SEM observations revealed the transition from a porous, weakly aggregated structure to a dense matrix filled with C–S–H and C–A–H gels, corroborating the macro–micro correlation. Overall, the combined use of lime and NaCl effectively converts dispersive clays into non-dispersive, mechanically improved geomaterials, providing a practical and sustainable approach for stabilizing problematic coastal soils in tropical environments. Full article

In response to the insufficiency of shear strength and severe segregation of cemented backfilling material in coal mines, a shear strength test, static segregation index test, and homogeneity degree test were carried out, taking slurry concentration (SC) as the main control factor. The effect law of SC on shear strength, the static segregation index, and the homogeneity degree was discussed. The relationship between the static segregation index and homogeneity degree and shear strength was analyzed, and the action mechanism of SC on shear strength was revealed. The research results show that for cemented backfill in coal mines, with a suspending agent content of 0 and a curing age of 28 d, when SC increases from 77% to 80%, shear strength increases by 31.43%, the static segregation index of the backfilling slurry decreases by 40.29%, and the homogeneity degree of the backfill increases by 69.23%. The increase in SC can enhance shear strength, reduce the segregation degree of backfilling slurry, and improve the homogeneity of backfill. The reason for the increase in shear strength lies in the fact that SC reduces the segregation degree of the backfilling slurry. The research in this paper has certain guiding significance for the timely support of the surrounding rock in the working face and the effective control of surface settlement. Full article

With aging, harsh working conditions or sports injuries, the meniscus can degrade, causing pains to the patient. Nowadays, the treatment consists of the surgical replacement of this cartilage. Since this procedure can lead to complications due to open wounds and potential infections, synthesizing a polyurethane-based injectable joint filler represents an interesting alternative. In this study, poly(δ-decalactone)triol oligomers and Lysine diisocyanate were chosen as starting monomers to create an isocyanate-based prepolymer, because of their biocompatibility and liquid state at room temperature. Nevertheless, to fully replace the meniscus, the joint filler must crosslink in vivo, and this should occur in a short time window. Accordingly, in this work, we studied the catalytic activity of a range of relatively safe compounds for the alcohol/isocyanate addition reaction. A preliminary ¹H NMR kinetic study of the catalyzed addition of 1-butanol or 3-pentanol on lysine diisocyanate ethyl ester at body temperature has been performed to reach this objective. Among catalysts, stannous octoate was the most effective with either primary or secondary alcohol, allowing them to reach 92 and 80% alcohol conversion, respectively. In addition, the conversion of the primary and secondary isocyanates of lysine diisocyanate ethyl ester was monitored for all the catalysts and revealed different behaviors depending on the catalyst employed. Stannous octoate, unlike the others, showed a similar reactivity for primary and secondary isocyanates with conversions of 49 and 47%, respectively. Finally, when employing the most effective catalyst, curing of the poly(δ-decalactone) triisocyanate with glycerol at 35 °C provided a polyurethane elastomer that exhibits an elastic modulus of 519 kPa and a swelling index lower than 3% in PBS, making it suitable for injectable polyurethane joint filler application. Full article

To address the limitations of microwave healing and the repair capabilities of conventional asphalt mixtures, this paper employs carbonyl iron powder as a filler to replace 20% of the mineral powder in asphalt mixtures, thereby enhancing their microwave absorption and healing properties. The study uses carbonyl iron powder mixtures as the experimental group and conventional asphalt mixtures as the control group. Using digital image correlation (DIC) technology, the semi-circular bending healing test and microwave heating test were conducted to determine the optimal conditions for microwave-induced healing and to investigate the effects of multiple healing factors on the healing outcomes. The test results show that the carbonyl iron powder asphalt mixture has the advantage of heating healing, and the intermittent heating method further improves the heating uniformity. The fracture energy healing index (HI_U) and the crack initiation time healing index (HI_t) are 83.1% and 34.9% higher than the ordinary asphalt mixture (microwave heating 100 s). Among the external healing factors, the microwave heating time has the greatest influence on the healing rate, followed by the degree of damage and the standing time. The optimal healing scheme is to stand for 4 h after microwave heating for 100 s, and the curing effect is the best at the initial stage of damage (before crack initiation). Full article

Expansive soils are clayey soils that undergo significant volume changes due to moisture content variations which can severely affect the stability of foundations and infrastructure. This study investigates the use of talcum powder as a novel stabilizing additive to reduce the swelling potential of expansive soils with particular focus on the behavior of the treated soil under curing conditions. Talcum powder concentrations of 5%, 10%, 15%, 20% and 25% by dry weight of soil was considered. A comprehensive series of laboratory tests were conducted, including swelling pressure, Atterberg limits, modified Proctor compaction and unconfined compressive strength at 4 curing times: 0 days, 7 days, 14 days and 28 days. In addition, mineralogical and microstructural analyses were carried out using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Experimental results revealed that incorporating talcum powder at a content of 25% by dry weight effectively reduced the swelling pressure by 37.5%. The compression index decreases with the increase in the talcum powder content. The results highlight the material’s significant capability to enhance the engineering properties of expansive soils, particularly under curing conditions and offer a cost-effective and readily available solution for soil stabilization applications. Full article

Calcium aluminate cement (CAC) offers rapid strength development, chemical durability in harsh environments, and high-temperature resistance, but its long-term performance may be compromised by the conversion of metastable hexagonal hydrates into stable cubic phases. Concurrently, recycling spent fluorescent lamp glass (SFLG) is limited because of its residual mercury content. This study investigates the use of manually (MAN) and mechanically (MEC) processed SFLG as partial CAC replacements (up to 50 wt.%). Both SFLG types had irregular morphologies with mean particle sizes of ~20 µm and mercury concentrations of 3140 ± 61 ppb (MAN) and 2133 ± 119 ppb (MEC). Moreover, the addition of SFLG reduced the initial and final setting times, whilst MEC waste notably extended the plastic state duration from 20 min (reference) to 69 min (50 wt.% MEC). Furthermore, strength development was accelerated, with SFLG/CAC mortars reaching peak strengths at 7–10 days versus 28 days as in the CAC reference. CAC and 15 wt.% SFLG mortars showed strength loss over time by reason of their phase conversion, whereas mortars with 25–50 wt.% SFLG experienced significant long-term strength gains, reaching ~60 MPa (25 wt.%) and ~45 MPa (35 wt.%), respectively, after 365 days, with strength activity indexes (SAI) near 90% and 70%, respectively. These improvements are attributed to the formation of strätlingite (C₂ASH₈), which stabilized hexagonal CAH₁₀ and mitigated conversion to cubic katoite (C₃AH₆). Mercury leaching remained below 0.01 mg/kg dry matter for all mixes and curing ages, classifying the mortars as non-hazardous and inert under Spanish Royal Decree 646/2020. The results suggest that SFLG can be safely reused as a sustainable admixture in CAC systems, enhancing long-term mechanical performance while minimizing environmental impact. Full article

With rapid industrialization, large quantities of industrial solid waste are generated annually. In Panzhihua, China, approximately 300,000 tons of limestone mine dust filter residue (LMDFR) is produced. This study investigates the properties of LMDFR and its potential as a supplementary cementitious material. LMDFR was blended with fly ash (FA) to replace 30% of cement in mortar. Tests were conducted to measure the mortar’s flowability and its compressive and flexural strengths after 7 and 28 days of curing, and XRD, SEM, TG, and DSC analyses were conducted on 28-day specimens. LMDFR primarily comprises ≥95% CaCO₃, with a specific surface area of ~1.3 m²/g and density of 2.694 g/cm³. Mortar flowability increased with LMDFR content, reaching 112.83% when used alone. Flexural strength was largely unaffected, while the 7-day compressive strength significantly improved. However, the 28-day strength decreased when LMDFR was used alone, with a 28-day activity index of 61.10%, compared with 71.52% for FA. A 1:1 blend of LMDFR and FA improved the activity index to 83.18%. Microstructural and thermal results corroborated strength and flowability trends. In conclusion, LMDFR demonstrates promising potential as a supplementary cementitious material in concrete applications. When blended with fly ash at a 1:1 ratio, the composite admixture significantly enhances flowability and early compressive strength while maintaining adequate long-term performance. This synergistic combination not only improves the physical properties of cement mortar but also provides a sustainable solution for the large-scale utilization of industrial solid waste. Full article

This study evaluated a light-cure orthodontic adhesive with the incorporation of bioactive glass particles and its effects on shear bond strength (SBS), adhesive remnant index (ARI), degree of conversion (DC), calcium release, and particle size distribution. Bioactive glass was added to the Transbond XT Adhesive (3M ESPE), resulting in five groups: TXT (0% wt of bioactive glass-incorporated—negative control); TXT20 (20% wt of bioactive glass-incorporated); TXT30 (30% wt of bioactive glass-incorporated), TXT50 (50% wt of bioactive glass-incorporated), and FLB (positive control—FL BOND II adhesive system with S-PRG particles, SHOFU Inc.). Data were analyzed with one-way ANOVA followed by Tukey’s test (α = 0.05). Quantitative SEM analysis confirmed submicron particle agglomerates (median equivalent circular diameter 0.020–0.108 µm). The TXT20 exhibited the highest values of degree of conversion (p < 0.05) (73.02 ± 3.33A). For SBS (in MPa): Control Group TXT—19.50 ± 1.40A, Group TXT20 18.22 ± 1.04AB, Group FLB 17.62 ± 1.45B, Group TXT30 14.48 ± 1.46C and Group TXT50 14.13 ± 1.02C (p < 0.05). For calcium release the group TXT50 2.23 ± 0.11D showed higher values (p < 0.05). The incorporation of distinct bioactive glass particle concentrations influenced the shear bond strength, degree of conversion, and calcium release. While the 50 wt% bioactive glass group exhibited the highest calcium release, both 20 wt% of bioactive glass group and the positive control group exhibited the highest degree of conversion without compromising the bonding strength. Full article

The present study explores the sustainable potential of volcanic ash sourced from the active Sakurajima volcano (Japan) as an eco-friendly alternative to Portland cement—a binder known for its high carbon emissions—in concrete and mortar production. The abundant pyroclastic material, currently a waste burden for the residents of Sakurajima and the Kagoshima Bay region, presents a unique opportunity for valorization in line with circular economy principles. Rather than treating this ash as a disposal problem, the research investigates its transformation into a valuable supplementary cementitious material (SCM), contributing to more sustainable construction practices. The investigation focused on the material characterization of the ash (including chemical composition, morphology, and PSD) and its pozzolanic activity index, which is a key indicator of its suitability as a cement replacement. Mortars were prepared with 25% of the commercial binder replaced by volcanic ash—both in its raw form and after mechanical activation—and tested for compressive strength after 28 and 90 days of water curing. Additional assessments included workability of the fresh mix (flow table test), apparent density, and flexural strength of the hardened composites. Tests results showed that the applied volcanic ash did not influence the workability of the mix and showed negligible effect on the apparent density (changes of up to 3.3%), although the mechanical strength was deteriorated (decrease by 15–33% after 7 days, and by 25–26% after 28 days). However, further investigation revealed that the simple mechanical grinding significantly enhances the pozzolanic reactivity of Sakurajima ash. The ground ash achieved a 28-day activity index of 81%, surpassing the 75% threshold set by EN 197-1 and EN 450-1 standards for type II mineral additives. These findings underscore the potential for producing low-carbon mortars and concretes using locally sourced volcanic ash, supporting both emissions reduction and sustainable resource management in construction. Full article

By proportionally blending fresh latex from PR107, Reyan 72059, and Reyan 73397, and employing both acid- and enzyme-assisted microbial coagulation methods, this study analyzed the effects of the specific latex formulation on the following: physicochemical properties, non-rubber components, molecular weight and distribution, vulcanization characteristics of compounded rubber, and physical–mechanical properties of vulcanized natural rubber. The results indicate that, compared to acid-coagulated natural rubber, enzyme-assisted microbial coagulated natural rubber exhibits slightly lower levels of volatile matter, impurities, plasticity retention index (PRI), nitrogen content, calcium ions (Ca²⁺), iron ions (Fe³⁺), and fatty acid content. Conversely, it demonstrates higher values in ash content, initial plasticity (P₀), Mooney viscosity (M_L(1+4)), acetone extract, magnesium ions (Mg²⁺), copper ions (Cu²⁺), manganese ions (Mn²⁺), gel content, molecular weight and distribution, and glass transition temperature (Tg). With the increase in the proportion of PR107 and Reyan 72059 fresh latex, the ash content, volatile matter content, fatty acid content, gel content, and dispersion coefficient (PDI) of natural rubber gradually decrease, while the impurity content, PRI, nitrogen content, weight-average molecular weight (Mw), and number-average molecular weight (Mn) gradually increase. Compared to acid-coagulated natural rubber compounds, enzyme-assisted microbial-coagulated natural rubber compounds exhibit higher minimum torque (M_L) and maximum torque (M_H), but shorter scorch time (t₁₀) and optimum cure time (t₉₀). Furthermore, as the proportion of PR107 and Reyan 72059 fresh latex increases, the ML of the compounds gradually decreases. In pure rubber formulations, enzyme-assisted microbial-coagulated natural rubber vulcanizates demonstrate higher tensile strength, tear strength, modulus at 300%, and Shore A hardness compared to acid-coagulated natural rubber vulcanizates. When the fresh latex ratio of PR107, Reyan 72059, and Reyan 73397 is 1:1:3, the tensile strength and 300% modulus of the natural rubber vulcanizates reach their maximum values. In carbon black formulations, the tensile strength and tear strength of enzyme-assisted microbial-coagulated natural rubber vulcanizates are significantly higher than those of acid-coagulated natural rubber vulcanizates in pure rubber formulations, with the increase exceeding that of other samples. Full article

Introduction: The World Health Organization has declared carbapenem-resistant organisms a research and development priority. Although ceftazidime–avibactam was approved around a decade ago, there is still a lack of prospective data on the treatment of resistant pathogens with this agent. Methods: We conducted a prospective, observational, single-center, investigator-initiated study of patients treated with ceftazidime–avibactam for infections caused by carbapenem-resistant organisms. The primary outcome was clinical cure 14 days after the initiation of ceftazidime-avibactam treatment. Secondary outcomes, which were assessed on day 30, included microbiological failure, development of resistance, all-cause mortality, and length of stay in the intensive care unit. Results: A total of 50 patients were included in the study. At baseline, the median Charlson Comorbidity Index and Sequential Organ Failure Assessment Score were 5.5 and 7. Approximately three-quarters of the patients were treated in an intensive care unit and had undergone mechanical ventilation within the previous 7 days prior to the commencement of ceftazidime–avibactam treatment. Half of the patients were diagnosed with nosocomial pneumonia. Most infections were caused by Pseudomonas aeruginosa (48%) and Klebsiella pneumonia (28%). Clinical cure at day 14 was achieved in 59% of patients. Four deaths (9%) and two cases of microbiological failure (4%) were observed. The median length of stay in the intensive care unit was 14 days. There was no emergence of resistance to ceftazidime–avibactam. Discussion: Our study contributes to the growing body of evidence supporting the effectiveness of ceftazidime–avibactam in treating infections caused by carbapenem-resistant organisms. In this cohort of critically ill patients, our results in terms of both clinical success and survival are in the upper range compared to those from mainly retrospective and some prospective studies. Although the benefits of ceftazidime–avibactam have been demonstrated in this and other studies, it must be prescribed cautiously to ensure it remains effective. Full article

Geopolymers, as an eco-friendly alternative construction material to ordinary Portland cement (OPC), exhibit superior performance in soil stabilization. However, their inherent brittleness limits engineering applications. To address this, polyethylene terephthalate (PET) fibers can be incorporated into a one-part geopolymer (OPG) binder to enhance ductility while promoting plastic waste recycling. However, the evaluation of ductile behavior of OPG-stabilized soil with PET fiber normally demands extensive laboratory and field experiments. Leveraging artificial intelligence, a predictive model can be developed for this purpose. In this study, data were collected from compressive and tensile tests performed on the OPG-stabilized soil with PET fiber. Four deep learning neural network models, namely ANN, BPNN, CNN, and LSTM, were then used to construct prediction models. The input parameters in the model included the fly ash (FA) dosage, dosage and length of the PET fiber, and the Curing Time. Results revealed that the LSTM model had the best performance in predicting the three ductile properties (i.e., the compressive strength index [UCS], strain energy index [CSE], and tensile strength index [TES]). The SHAP and 2D-PDP methods were further used to verify the rationality of the LSTM model. It is found that the Curing Time was the most important factor for the strength and ductile behavior. The appropriate addition of PET fiber of a certain length had a positive impact on the ductility index. Thus, for the OPG-stabilized soil, the optimal dosage and length of PET fiber were found to be 1.5% and 9 mm, respectively. Additionally, there was a synergistic effect between FA and PET on the ductility metric. This research provides theoretical support for the application of geopolymer and PET fiber in enhancing the ductility of the stabilized soil. Full article