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Synthesis and structural study of quinoline(μ1,μ3)-thiocyanate silver(I) complex
No full textA new quinoline(μ1,μ3)-thiocyanatesilver(I) complex, [Ag(Q)(SCN)]ₙ, (Q = quinoline, C9H7N) has been successfully synthesized through a direct reaction at room temperature between silver(I) nitrate, quinoline ligand, and potassium thiocyanate in a 1:1:1 molar ratio. Colorless crystals were obtained after nine days of evaporation. FT-IR analysis confirmed the presence of characteristic functional groups from both quinoline and SCN⁻ ligands. Refinement results from SC-XRD indicated that the silver(I) complex crystallizes in a pseudo-tetrahedral structure with an orthorhombic crystal system and space group P 212121(a = 4.0877(2) Å, b = 13.4948(8) Å, c = 18.0710(11) Å; α = β = γ = 90°). The R-factor value of 6.78% demonstrates that the refined structure is in close agreement with the actual molecular arrangement. Hirshfeld surface analysis further revealed intermolecular interactions with distances shorter than 8 Å, in which the dominant contact is H···H, contributing 29.2% of the total interactions. Antibacterial testing against Staphylococcus aureus and Escherichia coli revealed moderate activity, higher than the free ligands but lower than AgNO₃ and chloramphenicol, indicating that Ag(I) coordination enhances antibacterial performance
Electrochemical regeneration of NaBH₄ from the hydrolysis reaction of NaBH₄ with the Ni– Co/Hydroxyapatite catalyst as a part of the hydrogen release cycle
No full textSodium borohydride (NaBH4) is a high-hydrogen-content chemical hydride, but its practical use requires an efficient regeneration route from the hydrolysis by‑product (NaBO2·2H2O). This work investigates a two-step NaBH₄–H₂ cycle comprising catalytic hydrogen release and electrochemical regeneration of NaBH₄. A Ni– Co/hydroxyapatite (HAp) catalyst was synthesized by an electrochemical one-step deposition route (160 mA cm⁻2, 90 min). The catalyst shows nano-sized primary particles (≈10–100 nm) agglomerated into 1–5 μm secondary clusters. The results of catalyst characterization with FTIR confirmed the presence of HAp with additional peaks indicating surface carbonaceous species. XRD of the catalyst identifies a composite of HAp with oxidized Ni/Co phases (NiCo₂O₄ and CoO), evidencing successful incorporation of Ni–Co active phases on the HAp support. Mechanistically, the Ni/Co oxide surface is expected to provide hydrogen-activation (H* formation) and borate adsorption sites, while HAp enhances dispersion and interfacial hydroxyl/phosphate functionality—together facilitating the hydrogenation of NaBO₂·2H₂O toward NaBH₄ when H₂ is supplied electrochemically. In this work, NaBH4 was first hydrolyzed in water using an electrochemically synthesized Ni–Co/hydroxyapatite catalyst to release H2 and form borate, and the spent solution was then regenerated electrochemically in a two‑chamber cell separated by a bipolar membrane. In‑situ hydrogen generated via cathodic water reduction was utilized to convert NaBO2·2H2O back to NaBH4. Regeneration was evaluated at current densities of 0.10–0.20 A cm−2 for up to 120 min. NaBH4 concentration increased with both electrolysis time and current density, reaching ~0.020 mol L−1 at 0.20 A cm−2 after 120 min (compared with ~0.017 mol L−1 at 0.10 A cm−2). These results demonstrate the feasibility of coupling hydrogen release and electrochemical regeneration in a closed
Modelling of MOF-76(Nd) crystal growth and crystal habit modifications
No full textMOF-76(Nd) is composed of neodymium(III) ions linked by 1,3,5-benzenetricarboxylate (BTC) ligands to form a 3D polymer framework. MOF-76(Nd) has applications as an adsorbent for Cs(I) and Sr(II) ions in radioactive waste, as well as gas storage and drug nanocarriers. The adsorption capacity of a material depends on its crystal habits. Therefore, modification of MOF-76(Nd) crystal habits by studying and understanding crystal growth is necessary to control its adsorption capacity. However, MOF-76(Nd) crystal growth has not been studied experimentally or theoretically. For that reason, it is crucial to study crystal growth and modify the crystal habits of MOF-76(Nd), which is the purpose of this research, with the limitation of the scope to a theoretical study using
CrystalGrower. The research focuses on the effects of variations in supersaturation and screw dislocation. Theoretical modification using this software provides an efficient preliminary step before experimental implementation. The simulation results show that supersaturation plays an important role in determining crystal morphology and size. Crystals with an elongated needle-like morphology can be produced under low supersaturation conditions. Meanwhile, crystals with a shorter needle-like morphology can be produced under high supersaturation conditions. In addition, screw dislocation can change the layer-by-layer growth mechanism into a spiral growth mechanism and modify the crystal tips to be blunter. This study provides useful insights into the fundamental aspects of crystal growth and offers a preliminary framework that can guide experimental approaches for achieving desired crystal habits in practical applications
Fish Meal Production Optimization From Fish Processing Solid Waste Using Lipase And Protease Enzymes Addtion
No full textFish meal derived from solid waste in the tuna processing industry presents a sustainable opportunity to increase the value of by-products and manage waste. However, the quality of fish meal from solid waste processing is still poor, especially its relatively high fat content. This study investigated the quality changes of fish meal produced from tuna processing waste during various incubation periods (30, 60, and 90 minutes) before and after the addition of crude extracts of lipase and protease enzymes. The fish meal quality parameters tested were protein, moisture, fat, Total Volatile Basic Nitrogen (TVBN), and ash content. The results showed that the addition of crude extracts of lipase and protease enzymes and the incubation duration significantly affected the quality of fish meal. The fat content in fish meal was successfully reduced, which is good for product stability. The highest protein content reached 56.7%, but this value did not fully meet the industry standard of a minimum of 58%. In addition, the Total Volatile Basic Nitrogen (TVBN) value increased with longer incubation times, and the resulting value still exceeded the maximum standard of 130mg/100g Ash content remained stable within an acceptable range (maximum 22%), indicating consistent mineral retention. Furthermore, physical observations showed that more extended incubation periods resulted in a denser and smoother texture, which is advantageous for applications requiring consistency. These findings emphasise the need to optimise incubation conditions to improve the nutritional and physical properties of fish meal while addressing challenges related to protein degradation and freshness
Reconstruction of ethno-socioscientific issues in ciu bekonang and its relevance to SDGs in chemistry learning
No full textThe production of ciu bekonang, a long-standing tradition in Bekonang Village, Sukoharjo, Central Java, has attracted attention due to ethnosocioscientific issues related to product safety, social stigma, and environmental consequences. This study reconstructs the indigenous production practices of ciu bekonang into disciplinary chemistry concepts and evaluates the associated Ethno-Socioscientific Issues (Ethno-SSI) through the primary lenses of SDG 12 (Responsible Consumption and Production) and SDG 8 (Decent Work and Economic Growth), while positioning food security (SDG 2: Zero Hunger) as an indirect implication mediated by household income. A case study methodology was used to collect data through observation, in-depth interviews, and an examination of relevant literature. The reconstruction designates molasses (a by-product of sugarcane, Saccharum officinarum L.) as the primary feedstock subjected to fermentation and subsequent separation processes, including distillation, heating–condensation, fraction separation, alcohol content assessment, filtration, storage, and monitoring. The results show that the production chain helps people in the area make a living and makes the economy stronger (SDG 8). This context also show how important it is to value agro-industrial by-products and to handle and dispose of waste properly (SDG 12). The high alcohol content of ciu bekonang can be bad for health, and there is a social and cultural stigma around alcohol. The waste from making it could hurt the air, water, and soil. For chemistry education, this case provides an authentic Ethno-SSI context to teach fermentation, distillation, and environmental chemistry while engaging students in evidence-based inquiry and argumentation about sustainability
Fractionation, Phytochemical Profiling, and Antioxidant-Antimicrobial Activities of
No full textTadehagi triquetrum L., locally known as Duduk leaves, has long been used in traditional medicine for various treatments, including treating fever, liver disorders, and kidney ailments. However, systematic phytochemical and bioactivity studies on this species remain scarce. Unlike previous reports that mainly focus on crude extracts, this study integrates polarity-based fractionation, quantitative phytochemical analysis, antioxidant evaluation, antimicrobial testing, and Liquid Chromatography– Mass Spectrometry (LC-MS) profiling to provide a more comprehensive assessment of the bioactive potential of T. triquetrum L. leaves. The crude extract obtained from maceration with 70% ethanol yielded 28.49%. Subsequent fractionation using n-hexane, chloroform, ethyl acetate, and water produced yields of 6.52%, 0.90%, 12.82%, and 52.37%, respectively. Phytochemical screening revealed that the ethyl acetate fraction contained the highest levels of phenolics, tannins, and flavonoids. This fraction exhibited the strongest antioxidant activity in the DPPH assay (IC₅₀ = 0.71 μg/mL). LC–MS profiling identified 15 putative compounds, with catechin (26.84%) and kaempferol (14.58%) as the dominant constituents. The ethyl acetate fraction also demonstrated moderate to strong antibacterial activity against Staphylococcus aureus and Escherichia coli. These findings highlight T. triquetrum L. as a promising source of natural antioxidant and antimicrobial agents
Multi-mode optical absorber and sensor based on quasi-bound states in the continuum formed in double-layer metasurface
No full textQuasi-bound state in the continuum (quasi-BIC) is driving research direction in optical absorbing and sensing owing to the extremely narrow linewidth with almost non-radiative loss. However, it is usually revealed with a certain polarized light due to the asymmetry requirement and mainly holds for single or dual modes, making it unsuitable for many practical applications. Here we propose the multi-mode optical absorber and sensor that utilizes quasi-BIC based on periodically arranged double-layer silicon elliptical ring metasurface. By introducing asymmetry perturbation through separating the centers of the elliptic ring, the symmetry-protected BIC converts into leaky resonances, leading to the emergence of two Fano resonances and an electromagnetically induced transparency (EIT) for the x-polarized incident light, and three Fano resonances and an EIT for the y-polarized incident light. The multipole decomposition analysis and temporal coupled mode theory are employed to explain the underlying physics. Subsequently, this BIC-inspired metasurfaces is demonstrated as refractive index sensor with the maximal sensitivity nm/RIU and is utilized to enhance the optical absorption of graphene with the theoretical maximum absorption. Our results offer a possible solution for multi-mode quasi-BICs and open up possibilities for optical modulation and optical device development
Stable Hybrid Upwinding VAG scheme for the incompressible diphasic model with discontinuous capillary pressure
No full textIn this work, we propose an improved discretization, in terms of stability and accuracy, for the incompressible two-phase Darcy flows in a heterogeneous porous medium with discontinuous capillary forces. For this purpose, the total velocity formulation of the model is used. The coupled system is composed of a degenerate parabolic equation for the non-wetting phase and a pressure equation for the total velocity. We combine a positive Vertex Approximation Gradient (VAG) type scheme for the gradient fluxes with a hybrid upwinding of the mobilities. This approach entails a maximum principle on the saturations, which remain in their physical ranges. Energy estimates are obtained by selecting key approximations of the fluxes. These stability results allow to prove the existence of discrete solutions. Numerical experiments on complex test-cases show the robustness of the new approach in terms of the accuracy as well as the nonlinear convergence. Comparison to the usual phase potential upwinding approach and to a previous hybrid upwinding scheme are also provided
Interrégulations entre olfaction et métabolisme énergétique dans l’obésité et le diabète de type 2
No full textCette synthèse présente le rôle crucial de l’olfaction dans la régulation de l’homéostasie énergétique. Les neurones du système olfactif stimulent les aires cérébrales impliquées dans les émotions, la mémoire et le plaisir, et qui sont liées à l’alimentation. Ils sont modulés par le niveau du métabolisme énergétique corporel, qu’ils régulent en retour. La sensibilité olfactive diminue dans l’obésité et la chirurgie bariatrique la rétablit. Dans le diabète de type 2, l’apparition de troubles olfactifs peut prédire les troubles cognitifs. Enfin, dans un modèle murin de l’obésité, l’activation locale du système glucagon-like peptide-1 (GLP-1) dans le bulbe olfactif, première structure cérébrale codant les odeurs, induit une meilleure régulation de la glycémie et de la prise alimentaire. Le recrutement de cette nouvelle voie neurométabolique menant jusqu’au pancréas provoque une augmentation de la libération d’insuline et de la sensibilité à cette hormone
Nanoclay–magnetic nanoparticle composites for decentralized water purification
No full textMagnetic purification enables water treatment without membranes by combining selective surface chemistry with field-driven recovery of functional particles. Rather than forcing water through porous barriers that inevitably foul, magnetically responsive nanoparticles are dispersed directly in the aqueous phase, bind dissolved or suspended contaminants, and are collected through externally applied magnetic field gradients. This review presents the physical foundations of magnetophoresis and field-induced aggregation, together with recent developments in nanoclay–nanoparticle composite materials and open-channel magnetic architectures. Emphasis is placed on gradient engineering, regeneration physics, and transport phenomena under flow. Reported performance for the removal of hydrocarbons, dyes, and heavy metals is summarized, and available data on cycling stability and long-term durability are discussed. Life-cycle and sustainability aspects are examined, highlighting the advantages of regenerative operation and low chemical consumption. Overall, nanoclay–magnetic nanoparticle composites’ purification emerges as a physically grounded and practically scalable approach for local, near faucet water treatment