Tadulako University

In this study, acid leaching is used to extract rare earth elements (REEs) from monazite concentrate obtained from alluvial gold mining tailings. Then, precipitation and calcination were carried out as subsequent steps to recover REEs in oxide form. The process of applying hydrochloric acid (HCl), nitric acid (HNO3), and their mixtures, both with and without 10 % (v/v) hydrogen peroxide (H2O2), was varied in terms of temperature, acid concentration, and contact time to evaluate optimal leaching conditions. The mixed acid system of HNO3/HCl with H2O2 had the highest leaching efficiency compared to the single acid condition, achieving 93 % REEs dissolution under optimal conditions. Additionally, this mixed acid system demonstrated better solubility potential, as assessed by thermodynamics, compared to the single acid condition. The results of the leaching experiments were consistent with previous findings, supporting the efficient mixed acid method. With precipitation using 1.0 M oxalic acid, REEs were almost completely recovered from the wastewater, resulting in insoluble oxalate. Then, the precipitate was calcined for 120 min at a temperature of 700 degrees C, resulting in the formation of REEs oxide. X-ray diffraction (XRD) was used to determine the phase and crystal structure of the final product, verifying the transformation. The XRD results showed the formation of light REEs oxides (LaO2, EuO2) and heavy REEs oxides (TbO2, YbO2, HoO2, and CeO2), indicating successful phase transformation during calcination. This comprehensive acid-leaching-precipitation-combustion method demonstrated a beneficial approach for recovering REEs from mining waste, resulting in significant economic and environmental advantages for resource utilization in Indonesia.

Despite growing interest in South African medicinal plants, advanced metabolomic workflows that integrate positive (ESI+) and negative (ESI−) ionization modes in UPLC-MS/MS remain sparsely applied to South African flora, and especially to Acorus calamus and Lippia javanica species. Herein, application of a dual-polarity (positive (ESI+) and negative (ESI−) ionization modes) using an untargeted UPLC–MS/MS workflow, integrated with HEK293T cytotoxicity screening, to map their metabolomes, and rank potential signature metabolites for targeted antiviral follow-up. SwissADME supported in silico drug-likeness. Neither plant extract was cytotoxic across the concentration range, with absorbance-based cell viability of 73.82% for L. javanica and 77.23% for A. calamus at 250 µg/mL, and fluorescence-based cell viability ≥59.87% and ≥55.89%, respectively. Dual-polarity expanded coverage with ESI− yielded 312 features, compared with 225 with ESI+, consistent with the predominance of acidic phenolics in plant species. Unsupervised and supervised models segregated the plant species (PCA PC1/PC2 variance: ESI+ 89.4%/3.0%; ESI− 93.5%/1.8%; R2X(cum) = 0.799). Differential analysis identified 118 significant features in ESI+ with 80 up-regulated, 38 down-regulated, and 139 in ESI− with 96 up-regulated, 43 down-regulated. The ESI− showed the wider dynamic range. Chemotypes enriched among significant metabolites include flavonols of 3-O-methylkaempferol, apigenin, and conjugates of Pollenin A, iridoid glycosides of oleoside, forsythoside B, and jasmonate-pathway oxylipins of 7-epi-12-hydroxyjasmonic acid and its glucoside. These also include caryoptosidic acid and catechin-7-glucoside, which are ionized in both modes, pinning the increase in biomarker robustness. In conclusion, a dual-mode UPLC–MS/MS approach, integrated with cytotoxicity exploration, delivers a complementary metabolome coverage and a safety awareness for shortlisting of potential signature metabolites from L. javanica and A. calamus. Moreover, in vitro inhibition of SARS-CoV-2 papain-like protease (PLpro) by these plants links chemical signatures to antiviral relevance. Shortlisted significant metabolites that demonstrated favorable drug-likeness include flavonol scaffolds of 3-O-methylkaempferol, Pollenin A, and jasmonate-pathway derivatives of 7-epi-12-hydroxyjasmonic acid. Moreover, the dual ionization mode may eliminate ionization bias, broaden metabolome coverage, and yield a mechanism-ready shortlist of metabolites from South African medicinal plants for downstream antiviral investigation.

Agave angustifolia Haw fiber has high potential as reinforcement for green composites. However, its hydrophilic nature limits compatibility with polymer matrices. A novel cellulosic fiber from Agave angustifolia Haw was investigated by systematically comparing the effects of alkali and silane treatments. This work presents an integrated evaluation of structural, thermal, mechanical, and interfacial property changes resulting from the combined NaOH-(3-aminopropyl) triethoxysilane (APTES) treatment. FT-IR confirmed successful silanization through the Si-O-Si band at 1080 cm-1 and a degree of substitution of 1.32. The combined NaOH-APTES treatment resulted in the most significant improvement in fiber performance, with a 21.03% increase in the crystallinity index from 51.20% to 72.23%. This structural enhancement led to a marked increase in tensile strength from 212.116 f 40 MPa to 391.542 f 58 MPa and an increase in tensile modulus from 7.768 f 1.2 GPa to 21.634 f 1.3 GPa. Thermal stability was also enhanced, with the onset of degradation temperature reaching 334.10 degrees C. Surface modification increased fiber hydrophobicity, as indicated by a rise in the water contact angle from 37.32 degrees to 82.65 degrees. The NaOH-APTES-treated fiber also exhibited the highest interfacial shear strength (10.694 f 0.8 MPa), indicating improved fiber-matrix adhesion. SEM-EDX analysis confirmed a cleaner silanecoated surface with silicon detected at 1.09 f 0.15 wt%. These results highlight the potential application of NaOH-APTES-treated Agave angustifolia Haw fibers as reinforcement for high-performance green polymer composites with improved interfacial bonding, mechanical strength, and thermal stability.

Background: The rapid integration of digital technologies in secondary education has transformed English as a Foreign Language instruction, yet effective implementation remains uneven and highly contextual. While prior studies often focus on access or technological competence, less attention has been given to how teachers adapt pedagogically within real classroom conditions, particularly in regional Indonesian contexts. Aims: This study investigates how EFL teachers adapt their instructional practices in technology integrated classrooms, examining forms of implementation, contextual factors influencing adaptation, and teachers’ perceptions of instructional effectiveness. Methods: A qualitative multiple site case study was conducted at SMA Negeri 1 Palu and SMA Alkhairaat Palu in Central Sulawesi, Indonesia. Ten EFL teachers were selected through purposeful sampling. Data were collected through semi structured interviews and classroom observations between March and May 2025. The data were analyzed using thematic analysis following Braun and Clarke’s six phase framework, integrating inductive coding with theoretically informed interpretation. Results: The findings indicate that technology integration operates as a dynamic process of pedagogical negotiation rather than linear adoption. Teachers reorganized lesson structures, modified digital tasks in response to classroom contingencies, and recalibrated instructional decisions when facing infrastructural limitations. Professional experience influenced adaptive flexibility, with more experienced teachers demonstrating greater capacity for instructional redesign. Although digital tools enhanced student engagement, their effectiveness depended on deliberate scaffolding and pedagogical orchestration. Implications: This study advances a process-oriented understanding of pedagogical adaptation in technology-mediated EFL classrooms. The findings underscore the centrality of teacher agency and reflective judgment in sustaining meaningful digital learning environments. Professional development initiatives should therefore prioritize adaptive expertise and pedagogical reasoning rather than technical skill acquisition alone.

This study aims to develop a valid and practical HOTS-based ethnomathematics module rooted in the cultural context of the Sasambo Tribe to enhance elementary school students' understanding of spatial geometry. The module demonstrates how cultural contexts can make abstract mathematical concepts more concrete and engaging, providing a model for integrating local wisdom into the national curriculum. The study employed a Research and Development (R&D) method using the ADDIE (Analysis, Design, Development, Implementation, Evaluation) model. Quantitative data were analyzed using descriptive statistical techniques, with percentage scores calculated for each instrument. Qualitative data in the form of suggestions and comments from validators, students, and teachers were analyzed thematically to inform revisions at each stage. The validity test results indicated media validation at 92.4% and material validation at 94%, both categorized as highly valid. In the practicality test, the module achieved 92% in the small-group trial and 96.2% in the large-group trial based on student assessments, while teachers’ evaluations reached 100%, indicating a highly practical classification. The findings revealed that integrating Sasambo ethnomathematics with a HOTS approach increased student engagement in learning. The study concludes that the developed module meets the criteria of high validity and practicality and is suitable for use as an alternative teaching material in elementary mathematics instruction. Its structured design facilitates straightforward implementation by teachers, enhancing cultural relevance and fostering critical thinking skills in the classroom.