Science and Technology Indonesia

Effect of pH on Brazilin Extraction from Sappanwood (Caesalpinia sappan L.) and Its Impact on the Efficiency of Natural Dye-Sensitized Solar Cells (DSSCs)

Fri, 13 Mar 2026 00:00:00 +0000

Dye-sensitized solar cells (DSSCs) are a sustainable photovoltaic technology for addressing the global energy crisis through the conversion of solar energy using photosensitive dyes. This study aims to investigate the effect of pH variation during extraction on the optical, electrochemical, and photovoltaic characteristics of brazilin dye from sappanwood (Caesalpinia sappan L.) for DSSC applications. Brazilian extraction was performed using Microwave-Assisted Extraction (MAE) with pH conditioning from 2 to 12. UV-Vis spectroscopy showed an increase in light absorbance at 400–800 nm. The pH 8 dye exhibited a maximum absorption peak at 444.59 nm due to the formation of a quinoidal base through partial deprotonation of the hydroxyl (-OH) group. FTIR characterization confirmed the chemical structure of the dye with characteristic absorption spectra of broad bands at 3000–3500 cm^-1 for the phenolic hydroxyl group and peaks at 2800–3000 cm^-1 for aromatic C-H stretching vibrations, as well as aromatic C=C and C=O stretching vibrations at 1600–1400 cm^-1. Energy band gap analysis revealed that the dye at pH 2–12 has an energy gap range of 0.1788–0.5355 eV. Optimizing the extraction pH revealed that pH 8 yields the most effective dye performance, resulting in a peak DSSC efficiency of 2.17%, a minimal charge transfer resistance of 100 Ω, and the narrowest energy bandgap at 0.1788 eV. Weakly basic conditions enhance dye molecule conjugation, strengthen bonding with TiO₂, and optimize the overall charge transfer process. The research findings confirm the potential of optimizing natural dye extraction conditions as a strategy to enhance DSSC efficiency in a sustainable and environmentally friendly manner.

Biopotential of Gorontalo Hulu’u Fish (Giuris margaritacea) Albumin in a Novel Spray Gel Formulation for the Treatment of BurnWounds: In Vivo Evaluation in Rats

Fri, 13 Mar 2026 00:00:00 +0000

This study aimed to evaluate the efficacy of different concentrations of Hulu’u fish albumin-based spray gels in promoting wound healing in burn injuries in male white rats. The formulations included 10%, 15%, and 20% concentrations of Hulu’u fish albumin, which were compared to a commercial snakehead fish albumin gel (positive control) and a spray gel base without albumin (negative control). Wound diameter reduction was assessed over seven days. The results indicated a clear dose response relationship, with the 20% Hulu’u fish albumin formulation (F3) achieving the most significant reduction in wound diameter, averaging 1.57 mm (range: 1.5–1.6 mm), representing a 91.8% improvement compared to the negative control group, which showed an average reduction of 19.13 mm (range: 18.1–19.7 mm). The Positive Control (snakehead fish albumin gel) demonstrated a moderate reduction with an average of 6.97 mm (range: 6.6–7.6 mm). The 10% Hulu’u fish albumin (F1) and 15% Hulu’u fish albumin (F2) formulations showed moderate improvements, with average reductions of 4.73 mm (range: 4.4–5.1 mm) and 4.5 mm (range: 4.7–3.9 mm), respectively. These findings suggest that higher concentrations of Hulu’u fish albumin, particularly the 20% formulation, offer superior wound healing properties, outperforming both the negative control and the commercial snakehead fish albumin gel. The study highlights the potential of Hulu’u fish albumin as a novel bioactive compound for burn wound treatment and warrants further investigation for clinical applications.

Anticancer Efficacy of a Combination of Curcuma longa L. Rhizome and Annona muricata L. Leaf Extracts Against T47D Cells

Fri, 13 Mar 2026 00:00:00 +0000

Breast cancer remains one of the most prevalent malignancies worldwide. The use of combinations of natural products is increasingly recognized as a promising strategy for cancer treatment. Turmeric rhizome (Curcuma longa L.) and soursop leaves (Annona muricata L.) are two natural materials known for their anticancer potential. This study aimed to identify the phytochemical constituents of turmeric rhizome and soursop leaf extracts and to evaluate the anticancer activity of their combination against T47D breast cancer cells. Turmeric and soursop leaves were extracted with 96% ethanol using the maceration method. Raw material standardization was performed by measuring water content, ethanol-soluble content, and water-soluble content. The extract was standardized by thin-layer chromatography. T47D and Vero cell lines were used in this study. Compound identification was performed using Liquid Chromatography–Quadrupole Time-of-Flight Mass Spectrometry (LC/Q-TOF-MS). The candidate combination ratio was determined using the simplex lattice design approach in Design Expert 13 software. Cytotoxicity and antiproliferative effects were assessed using the MTT assay, while antimetastatic potential was evaluated through the scratch assay. Apoptosis and cell cycle arrest were analyzed by flow cytometry. $IC_{50}$ data were analyzed using one-way ANOVA, and post hoc testing was performed using Tukey’s multiple-comparison test. Antiproliferation and scratch assay data were analyzed using two-way ANOVA followed by the Bonferroni test. Apoptosis and cell cycle assay data were analyzed using one-way ANOVA followed by the Tukey post hoc test. Phytochemical profiling indicated the existence of fifteen chemicals in both turmeric rhizome and soursop leaf extracts. The candidate combination ratio of turmeric rhizome to soursop leaf extracts was 1:21, exhibiting cytotoxic activity with an $IC_{50}$ value of $32.2 \pm 2.5$ mL. The combined extract was associated with antiproliferative, anti-migratory, and pro-apoptotic responses and induced G2/M phase cell cycle arrest in T47D cells.

Valorization of Palm Empty Fruit Bunch-Derived K₂CO₃ Catalyst: Structural Analysis and Application in Biodiesel Production

Susila Arita, Reno Fitriyanti, Leily Nurul Komariah, Fitri Hadiah — Fri, 13 Mar 2026 00:00:00 +0000

This study investigates the synthesis and performance of a K2CO3 catalyst derived from oil palm empty fruit bunch (EFB) ash for sustainable biodiesel production. X-ray Diffraction (XRD) revealed a dominant K2CO3 crystalline phase, while X-ray Fluorescence (XRF) confirmed a high potassium content (>40%). Despite its low surface area (0.11 m2/g), the catalyst demonstrated high transesterification activity, achieving an optimal biodiesel yield of 85.89% with 3 grams of catalyst. Its high thermal stability, strong base sites, and macroporous structure all contributed to enhanced catalytic efficiency. Sustainability and techno-economic assessments indicate the catalyst’s potential to reduce production costs, utilize biomass waste, and lower greenhouse gas emissions. Thus, the EFB ash-based K2CO3 catalyst shows significant promise for supporting environmentally friendly biodiesel production and contributing to the transition to a green economy and renewable energy.

Microwave-Assisted Cocrystallization of p-Methoxycinnamic Acid with Saccharin and Nicotinamide: Comparative Effects on Solubility and Dissolution

Fri, 13 Mar 2026 00:00:00 +0000

p-methoxycinnamic acid (pMCA) has activity as an anti- inflammatory and analgesic but is difficult to dissolve in water with a solubility of only 0.712 mg/mL at 25 ^oC. Poor solubility will result a low dissolution rate so that drug absorption becomes limited, affects the bioavailability, and causes therapeutic effect to become less optimal. The formation of co-crystals are able to improve the solubility properties and dissolution rate by physically modifying the active compound. Cocrystals are crystalline materials composed of two or more molecules at specific stoichiometric ratios to form non-covalent bonds. Both saccharin and nicotinamide can be use as coformers because saccharin and nicotinamide were able to increase the solubility and dissolution rate of active compounds due to the formation of non-covalent bonds. The results showed that the formation of cocrystals using the microwave radiation had a higher solubility and dissolution rate of pMCA compared to pure pMCA. The pMCA-nicotinamide cocrystal increased solubility 1.29 times higher than a single pMCA while the pMCA-saccharin cocrystal increased solubility only 1.26 times higher than a single pMCA. In the dissolution rate test, the pMCA-Nicotinamide cocrystal increased the dissolution rate 3.67 times higher while the pMCA-Saccharin only increased 3.55 times higher than a single pMCA. These results show that both cocrystals have better solubility and dissolution rate properties than pure pMCA so it can be said that forming cocrystals can increase the solubility and dissolution rate of pMCA. Based on this study findings, it can also confirm that formation cocrystal pMCA using nicotinamide coformers has a
good solubility and dissolution rate than formation cocrystal using saccharin coformers.

Sustainable Corrosion Protection of Stainless Steel 316L in Marine Environment Using Electrophoretically Deposited Garlic Extract Green Inhibitor: Electrochemical and Surface Analysis

Fri, 13 Mar 2026 00:00:00 +0000

The increasing demand for sustainable and environmentally friendly corrosion inhibitors has driven research toward green alternatives to conventional toxic inhibitors. This study investigates the corrosion protection performance of garlic extract (Allium sativum) as an eco-friendly green inhibitor for stainless steel 316L in 3.5% NaCl marine environment. The inhibition efficiency was evaluated using electrochemical potentiodynamic polarization techniques, complemented by comprehensive surface characterization through scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry analysis. Electrophoretic deposition (EPD) was employed to apply garlic extract concentrations of 8, 10, and 12 mL onto SS316L specimens. Results demonstrated significant corrosion rate reduction from 0.0082732 mmpy (unprotected specimen) to 0.0014547 mmpy with 12 mL garlic extract treatment, achieving maximum inhibition efficiency of 82%. EIS revealed substantial increase in charge transfer resistance (>170 kΩ), while electrochemical analysis demonstrated mixed-type inhibition behavior with reduced corrosion current densities. SEM-EDX confirmed the formation of protective Fe²⁺-allicin complex layers on the metal surface, while Raman spectroscopy showed substantial reduction in corrosion products (a-Fe²O³ and y-FeOOH) formation. Cyclic voltammetry demonstrated a five-order-of-magnitude reduction in diffusion rate, confirming exceptional barrier properties. The superior performance is attributed to the chemisorption of sulfur and oxygen-containing compounds in allicin molecules onto active steel sites, forming stable protective films. This green inhibitor demonstrates excellent potential for sustainable corrosion protection in marine and industrial applications, offering an environmentally benign alternative to synthetic inhibitors.

Preparation of Polyacrylonitrile-Polyethersulfone Nanofibers Loaded with Reduced Graphene Oxide from Palm Kernel Shell forWastewater Filtration

Fri, 13 Mar 2026 00:00:00 +0000

The development of Polyacrylonitrile (PAN)–Polyethersulfone (PES) nanofiber membranes loaded with Reduced Graphene Oxide (rGO) offers an innovative and sustainable solution for water filtration. This study synthesized and characterized PAN–PES loaded rGO nanofiber membranes using an electrospinning technique. A PAN–PES mixture (8:2 mass ratio) at 10–20 wt% served as the matrix, with 48 mg of rGO added. The membranes were analyzed using scanning electron microscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), mechanical testing, water absorption, immersion resistance, and clean water permeability (CWP). The resulting nanofibers exhibited defect-free, bead-free, and uniform morphology with diameters ranging from 389 to 757 nm. FTIR confirmed hydrogen bonding between PAN–PES and rGO, while XRD showed sharp peaks with a maximum crystallinity of 33.52%. The membrane displayed a Young’s modulus of 57.83 MPa and remained stable after 32 days of immersion. It demonstrated superhydrophilic behavior with a contact angle of 72.4^o to 74.3^o, sustaining a stable water flux at 6.0 bar for 60 min, yielding a permeability of 3.25 to 23 L/m².h.bar and an equilibrium water content of 69 to 91%. Surface morphology before and after wastewater filtration revealed effective contaminant capture and strong antifouling resistance. These results confirm that PAN–PES loaded rGO nanofiber membranes possess excellent mechanical stability, high permeability, and superior wettability, providing a promising pathway for advanced, sustainable water filtration applications.

Relation Between Randic and Harmonic Energies of Commuting Graph for Dihedral Groups

Mamika Ujianita Romdhini, Athirah Nawawi — Fri, 13 Mar 2026 00:00:00 +0000

Consider a finite group G with center Z(G). This work examines the commuting graph $\Gamma_G$, a graph constructed from a group $G$ whose vertices correspond precisely to the noncentral elements of the group, that is, all elements in $G$ except those belonging to its center $Z(G)$. The graph is defined on the vertex set $G\backslash Z(G)$, where two distinct vertices v_p and vq are joined by an edge precisely when they commute, that is, whenever v_p v_q=v_q v_p. The number of vertices adjacent to v_p is denoted as d_vp, which is the degree of v_p. The Randic and harmonic matrices of $\Gamma_G$ are defined as square matrices in which $(p,q)-$th entry are $\frac{1}{\sqrt{d_{v_p} \cdot d_{v_q}} }$ and $\frac{2}{d_{v_p}+d_{v_q} }$ if $v_p$ and $v_q$ are adjacents, respectively; otherwise, it is zero. Randic energy is the sum of the absolute eigenvalues of the Randic matrix whereas harmonic energy is the sum of the absolute eigenvalues of the harmonic matrix. In this paper, we compare the Randic and harmonic energies of the commuting graph for non-abelian dihedral group of order 2n, D_2n.

Heterocyclic Azo Compounds, Synthesis, Characterization, Evaluation as Antimicrobial, and Theoretical Study

Mohammed K. Mohammed, Afrah A. Al-Jaber, Rafid H. Al-Asadi, Hawraa K. Dhaef — Fri, 13 Mar 2026 00:00:00 +0000

Five azo compounds, including N-(3-hydroxyphenyl) maleimide, were synthesized and characterized using FT-IR, ¹H-NMR, ¹³C-NMR, and mass spectroscopy. The compounds were evaluated for antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa using the disk diffusion method. The screening results showed that the azo compounds tested were effective against the bacteria tested, particularly Staphylococcus aureus. The geometry optimization of the molecular structures and the energy calculations for compounds 1-5 were performed using the density functional approach. Molecular docking was conducted to examine the interaction of the synthesized compound 1 with two bacterial receptors and one viral receptor (neuraminidase). It was found that they would target the PDB:4CJN protein, for which the compound yielded the lowest binding energy.

Optimization of Hydrolyzed Pumpkin (Cucurbita Moschata) Starch as Natural Superdisintegrant in Promethazine HCl Sublingual Tablets

Fri, 13 Mar 2026 00:00:00 +0000

Acid hydrolysis of pumpkin starch is a feasible strategy for developing novel pharmaceutical excipients, particularly natural superdisintegrants for sublingual and orally disintegrating tablet formulations. Given the requirement for extremely rapid tablet disintegration in sublingual dosage forms, selecting an efficient disintegrant is a critical formulation parameter. However, native pumpkin starch exhibits limited disintegration efficiency and generally requires high concentrations, which may adversely affect tablet hardness and friability. This study aimed to optimize the acid hydrolysis process of pumpkin starch and to evaluate the performance of the optimized hydrolyzed starch as a natural superdisintegrant in Promethazine HCl sublingual tablets. A factorial design was used to examine the impact of varying hydrolysis durations (3-9 days) and hydrochloric acid concentration (5-9%) on the physicochemical characteristics of the modified starch. The optimized hydrolyzed starch demonstrated a near-neutral pH (5.17 ± 0.03), acceptable moisture content (LOD 10.20 ± 0.44%), and excellent flow properties, as indicated by a low angle of repose (23.96°) and Carr’s index (9.99%). Scanning electron microscopy revealed increased surface irregularity and porosity, while FTIR analysis indicated enhanced exposure of hydroxyl groups, consistent with partial depolymerization of the starch polymer. The amylose content increased to 35.17%, accompanied by improved water uptake and swelling capacity. The effective pore radius (25.03 ± 0.35 µm) and swelling index (70.25 ± 0.57) were markedly higher than those of native pumpkin starch (12.27 µm and 44.30 ± 0.85, respectively), although slightly lower than crospovidone (27.65 µm and 99.97 ± 0.13). Incorporation of the hydrolyzed starch into Promethazine HCl sublingual tablets resulted in formulations with adequate mechanical strength (hardness 3.35 ± 0.05 kg), low friability (0.53 ± 0.04%), rapid disintegration (49.18 ± 0.75 s), and high drug release (96.79 ± 0.13%). These performances were comparable to those of crospovidone and superior to formulations containing native pumpkin starch. The improved tablet characteristics were primarily attributed to enhanced porosity and swelling capacity induced by acid hydrolysis. Overall, optimized hydrolyzed pumpkin starch demonstrates considerable potential as a sustainable, biodegradable, and cost-effective natural superdisintegrant for fast-disintegrating pharmaceutical tablet formulations.

Tuning Magnetic Behavior of La₁₋ₓSrₓFeO₃ (x = 0.1–0.5) via Sr Doping: From Antiferromagnetism to Ferromagnetism

Ramlan, Marzuki Naibaho, Masno Ginting — Fri, 13 Mar 2026 00:00:00 +0000

Strontium-substituted LaFeO₃ compounds with the chemical formula La₁₋ₓSrₓFeO₃ (x = 0.1–0.5) were successfully prepared via the solid-state reaction technique by partially replacing La at the A-site. Structural analysis was carried out using X-ray diffraction (XRD), while surface morphology and elemental composition were investigated by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS). The magnetic behavior of the samples was evaluated using a vibrating sample magnetometer (VSM). XRD patterns confirmed that all synthesized compositions crystallized in a single-phase LaFeO₃ structure without detectable impurity phases. The dominant diffraction peak corresponded to the (121) crystallographic plane, indicating an orthorhombic structure with the Pnma space group (No. 62). SEM observations revealed irregular particle morphologies with a broad particle size distribution. EDS analysis verified the successful incorporation of Sr into the LaFeO₃ lattice, as evidenced by the presence of La, Fe, O, and Sr elements in all doped compositions (x = 0.1–0.5). Magnetic measurements showed that the La₀.₉Sr₀.₁FeO₃ sample exhibited the best magnetic performance, with a saturation magnetization (Mₛ) of 0.393 T and a coercive field (Hc) of 2661 Oe. The introduction of Sr induced a transition in magnetic behavior from antiferromagnetic to ferromagnetic ordering. Overall, these results demonstrate that La₁₋ₓSrₓFeO₃ materials are promising candidates for electromagnetic wave absorption applications.

Hierarchically Structured Zn-Al LDH/Hydrochar from Rambutan Peel (Nephelium lappaceum L.) for Enhanced Fe(II) Adsorption

Desti Erviana, Normah Normah, Heroldinho Arieveali, Navinda Ramadhan — Fri, 13 Mar 2026 00:00:00 +0000

Dissolved ferrous ions in water pose significant environmental and operational challenges, necessitating efficient and sustainable removal technologies. In this study, a hybrid adsorbent was developed by integrating Zn-Al layered double hydroxide (LDH) with hydrochar derived fromrambutan peel (Nephelium lappaceum L.) via coprecipitation. Characterization confirmed successful composite formation with a substantial increase in specific surface area from 9.621 m².g^-1 for pristine Zn-Al LDH to 52.964 m².g^-1 for the composite, accompanied by enlarged pore volume and enriched oxygen-containing functional groups. Batch adsorption experiments showed strong pH dependence, with optimal Fe(II) removal at pH 6 and equilibrium reached within 120 min. The Zn-Al LDH@NL-HC composite exhibited a markedly higher adsorption capacity (51.501 mg.g^-1) compared with Zn-Al LDH (15.692 mg.g^-1) and hydrochar alone (8.594 mg.g^-1), indicating a significant synergistic effect. Isotherm analysis revealed a maximum adsorption capacity of 76.336 mg.g^-1 at elevated temperature, while kinetic data followed a pseudo-second-order model, suggesting chemisorption-dominated uptake. Thermodynamic parameters indicated an endothermic and spontaneous process. Regeneration studies demonstrated excellent stability, with adsorption efficiency maintained at 79.48% after five cycles. The superior performance is attributed to combined mechanisms including electrostatic attraction, surface complexation with oxygen-rich groups, ion exchange within LDH interlayers, and diffusion into mesoporous structures. These findings demonstrate the effective valorization of agricultural waste into a high-performance and reusable adsorbent for Fe(II) remediation in aqueous systems.

ZnO-SiO₂ Nanocomposite: Synthesis, Characterization, and Application of Corrosion Inhibition

Alam Q. AL-Hussin, Ali Taleb Bader, Hazim Yahya Al-Gubury — Fri, 13 Mar 2026 00:00:00 +0000

Herein, we are reporting the synthesis of zinc oxide (ZnO), silicon dioxide (SiO₂), and a binary nanocomposite ZnO-SiO₂ by the co-precipitation method. The materials were comprehensively characterized, such as via Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), powder X-ray diffraction (XRD), UV–Vis spectroscopy, and nitrogen adsorption–desorption (BET) measurements before their application. The presence of typical Zn-O and Si-O vibrations characteristic of ZnO was confirmed by FTIR spectra, whereas the hexagonal morphology of ZnO crystals, spherical SiO₂, and agglomerated ZnO-SiO₂ nanostructures were confirmed by SEM images. XRD measurements showed the crystallinity of the as-obtained nanostructures and the average crystallite sizes of 37.78 nm for ZnO, 48.01 nm for SiO₂, and 34.09 nm for composite ZnO-SiO₂ as determined by the Scherrer equation. The synthesized ZnO, SiO2, and ZnO-SiO2 nanoparticles were then evaluated on the basis of their inhibitive abilities toward corrosion processes in mild steel coupons exposed to 1M HCl estimated by potentiodynamic polarization. All the studied binary composites emerged as having the strongest inhibitory potential, with the ZnO-SiO₂ nanocomposite root system experience showing the most powerful inhibition potential, reducing the corrosion current density i-corr to 36.1 µA cm-2 and reaching 93% inhibition efficiency. These results demonstrate that the future of using co-precipitation-based synthesis lies in the ability to obtain tunable nanostructure composites with desirable physicochemical properties and efficient corrosion inhibition in acidic media

Prime and Odd Prime Labelings on Cycle-Related Graphs

Hafif Komarullah, Noor Hidayat, Vira Hari Krisnawati, Kristiana Wijaya — Fri, 13 Mar 2026 00:00:00 +0000

Graph labeling is the process of determining integer values for vertices, edges, or both, based on certain criteria. Let G be a simple graph with the finite vertex set V(G). Prime labeling of G is a bijection ⍺:V(G)→{1,2,…,|V(G)|} for which each pair of adjacent vertices exhibits relatively prime labels. This concept has been extended to odd prime labeling, defined as a bijection ⍺:V(G)→ {1,3,...,2|V(G)|-1} satisfying the condition that the labels assigned to adjacent vertices are relatively prime labels. A graph that displays a (odd) prime labeling is designated as a (odd) prime graph. A recent conjecture state that every prime graph is an odd prime graph. In the present study, we conduct an investigation concerning prime and odd prime labeling, focusing on a range of cycle-related graphs classes. Our methods include the axiomatic descriptive approach and pattern detection techniques. We show that volcano graphs, C_3 ⨀_(x_1 y_0 ) F_n, C_3⊚K ̅_n, tadpole graphs, palm trees, and C_l ⨀_(x_1 y_0 ) mP_(n+1) are all both prime and odd prime graphs.

Enhancing Chitosan-Carboxymethyl Chitosan Composite Film Properties by Silver Nanoparticles Grafting for Acne vulgaris

Septian Dwi Mulyana, Muh. Agus Syamsur Rijal, Retno Sari — Fri, 13 Mar 2026 00:00:00 +0000

Silver nanoparticles (AgNPs) have been widely used in developing antibacterial preparations. AgNPs are used in film preparation to enhance the film’s antibacterial properties. The combination of natural polymers is an effective strategy to enhance mechanical properties, prolong degradation time, preserve gas and vapor permeability, and maintain biocompatibility. This research aims to develop an AgNP-chitosan-carboxymethyl chitosan (CMChi) nanocomposite film that exhibits desirable physical properties and enhances antibacterial activity by incorporating AgNPs. Chitosan-CMChi composite films were prepared using the solvent casting method. Characterization and antibacterial tests using Propionibacterium acnes (P. acnes) were carried out for AgNO3 and AgNP-chitosan-CMChi nanocomposite films. The results showed that a 1 mM AgNO3 solution with 1% lime powder at pH 9 was the optimal formulation for AgNP formation, exhibiting an absorbance of 4.631 at 408.1 nm, a particle size of 68.4 nm, and antibacterial activity. To optimize the chitosan-CMChi composite film, a formula of 1.5% chitosan and 1.5% CMChi was selected, yielding a tensile strength value of 0.514 MPa. The AgNP solution was then added. In the AgNP-chitosan-CMChi nanocomposite film, it was observed that increasing the AgNP volume affected the mechanical strength of the film. The antibacterial activity of the AgNP-chitosan-CMChi nanocomposite film increased with the AgNP concentration. Combining AgNPs with the chitosan-CMChi polymer yields nanocomposite films with good physical properties and enhanced antibacterial activity against P. acnes compared with films without AgNPs.

Spatial Data Science for Regional Pattern Analysis: Dynamic Time Warping-Based Clustering of East Java’s Economic Indicators

Rahma Fitriani, Eni Sumarminingsih, Herman Cahyo Diartho — Fri, 13 Mar 2026 00:00:00 +0000

Motivated by the need to better capture dynamic regional disparities, this study examines spatial and temporal development patterns in East Java, Indonesia, using spatial panel data from 2020 to 2023. A data-driven framework is proposed that integrates Principal Component Analysis (PCA) for dimensionality reduction, Dynamic TimeWarping (DTW) for temporal similarity measurement, and spatially constrained clustering using the SKATER algorithm. PCA compresses multiple socio-economic indicators, GDP growth, GDP level, Human Development Index (HDI), and population density, into a unified development profile, enabling comparison of regional trajectories over time. DTW captures non-linear temporal alignment, while SKATER preserves spatial coherence in cluster formation. The resulting clusters are used to construct an endogenous spatial weight matrix that reflects functional regional relationships rather than purely geographic adjacency. Validation using Moran’s I indicates stronger spatial autocorrelation compared to conventional contiguity-based weights, suggesting improved representation of spatial interaction. Four clusters reveal distinct development patterns and uneven regional trajectories. By integrating dimensionality reduction with temporal alignment and spatial clustering, the proposed approach extends dynamic spatial weighting toward a functional interpretation of regional dependence and offers a transferable framework for spatial data science and regional policy analysis.

Evaluation of Photocatalytic and Catalytic Activity of Biochar/Nickel for Laboratory Wastewater Treatment

Fri, 13 Mar 2026 00:00:00 +0000

In this investigation, an exploration on the use of low-cost effective methods for laboratory wastewater treatment using magnetic biochar has been conducted. Magnetic biochar derived from orange peel waste loaded with nickel nanoparticles (Biochar/Ni) was prepared by pyrolysis procedure of orange peel waste with nickel chloride as nickel precursor at 600 ^oC for 2 h. X-ray diffraction (XRD), scanning electron microscopy-energy dispersive x-ray (SEM-EDX), Raman spectroscopy, and vibrating sample magnetometer (VSM) were employed for identify the feature of Biochar/Ni. Photocatalytic, photocatalytic oxidation, and microwave-assisted catalytic peroxidation were the treatment procedures employed to evaluate the activity of Biochar/Ni. The results showed the dispersed nickel nanoparticles in the composite are photocatalytic system to produce radicals for decolorizing laboratory wastewater as proven by accelerated oxidation by the addition of H₂O₂ and S₂O₈^2- as oxidants, and inhibition by the addition of radicals and superoxide radical scavengers. In addition, microwave-irradiation intensified catalytic peroxidation with shorter time and higher decolorization efficiency. The greenness evaluation of the process using AGREE software addressed the microwave-assisted catalytic peroxidation as the most efficient procedure utilizing Biochar/Ni for being developed and implemented to organic contaminated wastewater.

Large SiO₂ Sizes Influencing Light Scattering Properties in Original White LED Structure

Pham Hong Cong, Nguyen Thi Phuong Loan, Hsiao-Yi Lee — Fri, 13 Mar 2026 00:00:00 +0000

Previously, SiO₂ particles (1-10 wt%, <10 µm) were proposed to augment the light flux and correlated color temperature (CCT) deviation in conventional blue-excited LEDs. This research paper explores the application of larger SiO₂ particle sizes within a conventional LED model. SiO₂ particles with diameters ranging from 1 µm to 20 µm were analyzed for their scattering properties using the Stöber method, a Mie-scattering-based MATLAB program, and LightTools software to simulate the optical attributes of a phosphor-transmuted WLED apparatus, supported by XRD, SEM, and other analytical techniques. SiO₂ was integrated into the yellow phosphor YAG:Ce layer to induce scattering phenomena within the active layer. Through our investigation, the concentrations of SiO₂ and YAG:Ce phosphor were consistently maintained at 5 wt% and 10 wt%, respectively. Our findings focus on assessing backward scattering with larger SiO₂ sizes. Modulating the sizes of SiO₂ spheres reduced CCT deviation and enhanced both flux output and color rendering performance. These results emphasize the potential utility of larger SiO₂ particles in enhancing white LED performance and facilitate further investigation to optimize their usability in production processes.

Synthesis, In-Vitro Evaluation, and Computational Investigation of Salicylic Hydrazide Derivatives as Potential Tyrosine Kinase–Targeted Anticancer Agents

Fri, 13 Mar 2026 00:00:00 +0000

A series of N₂-acyl salicylic hydrazides (S2-S6) and N-(substituted benzylidene) salicylic hydrazides (S7-S9) were synthesized from 2-hydroxybenzohydrazide (S1), using both microwave irradiation and conventional methods, and tested for its in vitro anticancer activity against human lung cancer cell, A549. The salicylic hydrazides were successfully synthesized in good yields (79–98%) and the in-vitro study results indicated that 3,4-dichloro-N'-(2-hydroxybenzoyl)benzohydrazide (S5) was most active among the tested compounds (IC₅₀ value of 68.75 µM). In this work, we applied an integrated approach combining network pharmacology and computational analysis to explore how salicylic hydrazide derivatives affect tyrosine kinase–related pathways. The in-silico findings were in agreement with the in vitro results, indicating that compound S5 produced a docking score of –6.53468 kcal/mol. The findings of this research are expected to support further development toward identifying promising anticancer drug candidates derived from salicylic hydrazide derivatives.

The Influence of Milling on the Structural and Morphological Properties of Waste-Based Active Carbon from Rubber Seeds Using High Energy Milling (HEM) Method

Fri, 13 Mar 2026 00:00:00 +0000

The high-energy milling (HEM) synthesis method has produced activated carbon powder from rubber ore shell waste. The activated carbon was prepared using a chemical method with activation temperatures varying between 400, 500, and 600°C. Temperature optimization resulted in activated carbon with a maximum carbon content at 600°C. The activated carbon was then milled for various times: 0, 30, 60, and 90 minutes. The crystallinity and surface morphology of the samples were then confirmed using an X-ray diffractometer (XRD) and scanning electron microscope (SEM) characterization. Based on the XRD graph, the percentage of structural regularity, or degree of crystallinity, of the activated carbon tended to decrease from 18.17% without milling treatment to 17.52% at 30 minutes of milling, 17.45% at 60 minutes of milling, and 17.35% at 90 minutes of milling. SEM images also show a decrease in the average pore diameter from approximately 0.45 µm to 0.20 µm with a more homogeneous intraparticle morphology structure when the milling time is increased from 30 minutes to 90 minutes. This study demonstrates the potential of rubber seed shell waste for processing into activated carbon. The HEM method can significantly reduce the grain size of activated carbon and increase its surface area and reactivity, making it more effective in applications as an adsorbent and filter.

Utilization of Diatom Frustule Waste from Navicula sp. TAD as Photoelectrode Material for Enhancing the Efficiency of Dye-Sensitized Solar Cells (DSSC)

Fri, 13 Mar 2026 00:00:00 +0000

Navicula sp. TAD is a microalga with silica-based cell walls, offering potential to improve photon interaction in dye-sensitized solar cells (DSSCs). This study combined Navicula sp. TAD frustules with TiO₂ to fabricate DSSC working electrodes. The objectives were to isolate and characterize the frustules, optimize the TiO₂–frustule ratio, and evaluate photoelectric performance. The workflow consisted of cultivating Navicula sp., isolating pigments and frustules, fabricating solar cells with varied electrode compositions, and performing photoelectric testing under a solar simulator. Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and Scanning Electron Microscope (SEM) analysis confirmed that the frustules possess nanoporous surfaces and exhibit Si–O–Si and Si–OH functional groups. Electrodes incorporating TiO₂–frustule blends showed compact pore networks, along with additional functional groups. Performance screening across compositions identified an optimal TiO₂–frustule ratio of 40:60, which delivered an efficiency of 10.51%, a short-circuit current density of 0.673 A, an open-circuit voltage of 301.8 mV, and a fill factor of 0.32. These findings indicate that frustule-enabled light management and surface chemistry can jointly enhance dye loading and charge collection in DSSC photoanodes relative to TiO₂ alone.

Some Properties of Generalized Token Graphs

Fri, 13 Mar 2026 00:00:00 +0000

The generalized k-token graph GF_k(G) is a graph with the k-subsets of V(G) as the vertices, and two different vertices are adjacent if and only if the symmetric difference contains at least one edge of G. This model extends the classical k-token graph by relaxing the adjacency condition, leading to increased edge density and altered topological properties. In this paper, we establish the fundamental properties of GF_k(G), including its connectivity, duality, and monotonicity. We provide exact formulas for the vertex degrees and the total size of GF₂(G), along with combinatorial bounds for k > 2. Furthermore, we characterize the girth and clique numbers, proving that GF_k(G) is highly prone to containing triangles even when the base graph is triangle-free. We also explore the inheritance of Hamiltonicity and bipartiteness, demonstrating that while connectivity is preserved, bipartiteness is lost for almost all bipartite graphs with at least four vertices. Our results provide a comprehensive structural characterization of this generalization, bridging the gap between classical token graphs and broader set-theoretic graph constructions.

Non-Inclusive and Inclusive Distance Irregularity Strength of Complement and Split Graphs

Tita Khalis Maryati, Fawwaz Fakhrurrozi — Fri, 13 Mar 2026 00:00:00 +0000

Let $f$ be a map from vertices of a graph $G$ to number from $1$ to $k$. The labeling $f$ is called distance irregular if for every two vertices $x$ and $y$, it holds that $wt_f(u) \ne wt_f(v)$ where a weight $wt_f(u)$ is defined as the sum of labels of the neighbors of $u$. Moreover, the labeling $f$ is called inclusive distance irregular if for every two vertices $x$ and $y$, $wt_f(u) \ne wt_f(v)$ with a weight $wt_f(u)$ is defined as the sum of the label of $u$ and the labels of the neighbors of $u$. The least number $k$ where there exists a distance irregular labeling (resp. inclusive distance irregular labeling) is called a distance irregularity strength (inclusive distance irregularity strength), denoted by $\text{dis}(G)$ $(\widehat{\text{dis}}(G))$. In this paper, we present a connection of distance irregular labeling and inclusive distance irregular labeling in a graph with its complement. In particular, we derive a new upper bound for distance irregularity strength and inclusive distance irregularity strength of any graph. Further, we determine the $\text{dis}(G)$ and $\widehat{\text{dis}}(G)$ for certain special family of split graph $G$ and provide examples of a graph $G$ satisfying $\text{dis}(G) = \widehat{\text{dis}}(G)$.

Anticancer Activity of Trisubstituted Pyrazoline Derivatives: Synthesis, Characterisation, and Computational Studies

Fri, 13 Mar 2026 00:00:00 +0000

The search for new anticancer drugs that target apoptotic and autoimmune pathways is essential, as these pathways are crucial for maintaining cellular homeostasis and destroying cancer cells. In this study, eight trisubstituted pyrazoline derivatives (2a-d and 3e-h) were synthesised through a cyclocondensation reaction of chalcones with hydrazide derivatives (hydrazine hydrate and phenyl hydrazide). These derivatives were characterised using EI-MS, ¹H NMR, ¹³C NMR (both 1D and 2D), and ¹⁹F NMR spectra. Their cytotoxic activity against the MCF-7 tumour cell line was tested with the MTT assay. The results showed that compounds 2a-d had the most potent inhibitory effect on MCF-7 cell growth, with IC₅₀ values of 19.46, 29.45, 44.15, and 26.37 µg/mL after 24 hours of exposure. Among them, compound 2a was the most potent. In comparison, compounds 3e-h had significantly higher IC₅₀ values of 101.67, 75.99, 102.83, and 99.54 µg/mL, respectively, than the reference drug doxorubicin, which has an IC₅₀ of 1.24 µg/mL. Additionally, docking of compound 2a showed good binding affinity values with the protein (PDB ID: 5T92) amino acid residues in different interactions: H-donor, H-acceptor, and H-pi, as well as two H-acceptor and pi-H interactions with the water and other amino acids. The most favourable binding pose corresponded to the lowest ΔG and exhibited robust pose quality. The molecular structures of compounds 2a-d were optimised using the B3LYP functional and the 6-311+G(d) basis set, and their quantum chemical properties were analysed through molecular orbital studies.

Geospatial Intelligence (GEOINT)-Based Cyber Warfare Exposure Index (CWEI) Mapping of Indonesia's Strategic Infrastructure

Anugrah Adityayuda, Asep Adang Supriyadi, Syachrul Arief — Fri, 13 Mar 2026 00:00:00 +0000

The increasing integration of digital systems into critical infrastructure has transformed cyber warfare into a systemic national security risk with strong spatial characteristics. In Indonesia, rapid digitalization and uneven infrastructure development have expanded the cyber-attack surface, while existing studies remain largely qualitative or rely on aggregated national indices that fail to capture subnational exposure patterns. This study addresses this gap by developing a Cyber Warfare Exposure Index (CWEI) based on Geospatial Intelligence (GEOINT) to assess provincial-level exposure across Indonesia. The index integrates seven indicators, energy, transportation, telecommunications, government facilities, internet penetration, night-time light intensity, and urbanization, derived from open-source geospatial data and official statistics. All indicators were normalized using min–max scaling and aggregated through equal weighting, with robustness tested using Principal Component Analysis (PCA), Pearson correlation, and One-at-a-Time sensitivity analysis. Results reveal strong spatial disparities in cyber warfare exposure, with CWEI values ranging from 0.019 to 0.746. DKI Jakarta exhibits the highest exposure (CWEI = 0.746), followed by West Java (0.573) and Central Java (0.564), while several eastern provinces fall into the very low exposure category. The equal-weight and PCA-based indices show near-perfect agreement (R² = 0.997; r = 0.998), confirming high methodological robustness. Global Moran's I (0.689; p < 0.001) indicates significant positive spatial clustering of exposure. These findings demonstrate that cyber warfare exposure in Indonesia is highly concentrated and spatially structured, underscoring the need for regionally prioritized, risk-based cyber defense strategies.

Design and Formulation of Hydrogel Sponges for Mesenchymal Stem Cell Secretome Delivery

Deni Noviza, Syahda Permata Ardelia, Marlina — Fri, 13 Mar 2026 00:00:00 +0000

The mesenchymal stem cells (MSCs) secretome plays multiple roles in tissue regeneration and wound healing due to its content of various bioactive factors, including Fibroblast Growth Factor-2 (FGF-2). To support its topical application, an effective delivery system is required to preserve the stability and bioactivity of the secretome. A hydrogel sponge based on PVA-HPMC-PEG was selected as the delivery matrix due to its porous structure, flexibility, and ability to release active substances, thereby making it a promising candidate for wound healing applications. The objective of this research was to formulate a PVA-HPMC-PEG-based hydrogel sponge for a secretome delivery system. The hydrogel sponge was prepared using the freeze-drying method and optimized by varying the PVA concentration to achieve the desired physicochemical characteristics. The optimal formulation (F4) consists of 20% PVA, 2% HPMC, and 7.5% PEG. Evaluation revealed that this formulation exhibited a flexible sponge-like structure with a swelling percentage of 279.793% ± 0.06, elongation percentage of 107.923% ± 4.98, and physical crosslinking confirmed by FTIR analysis. Scanning Electron Microscopy (SEM) analysis demonstrated pore size ranging from 20 to 215 μm. Furthermore, secretome release was assessed using a Franz diffusion cell, and FGF-2 levels were quantified via ELISA. The results confirmed that the hydrogel sponge effectively facilitated the release of the secretome.

Block Bootstrap for Spatiotemporal Data in Generalized Space Time Autoregressive (GSTAR)

Fri, 13 Mar 2026 00:00:00 +0000

Generalized Space-Time Autoregressive is a model that can be used for data with spatial and temporal dependence. The GSTAR model is widely used in various phenomena such as rainfall, temperature, inflation, and others. GSTAR assumes normality of errors and non-autocorrelation. If the assumption of normality of errors is not met, then inference on parameters cannot be made. One solution to this problem is to use bootstrapping. However, bootstrapping for spatiotemporal data in the GSTAR model has not been developed. Therefore, this study aims to develop a bootstrapping method for spatiotemporal data in the GSTAR model. This development is done by adapting bootstrapping methods for time series data, namely, the non-overlapping block bootstrap (NBB) and the moving block bootstrap (MBB). This research continued with a series of simulations to evaluate the performance of the block bootstrap method as the number of observations, block length, and number of bootstrap replications were varied. Furthermore, the method’s effectiveness was tested using rainfall data from Malang Regency. Simulation results show that both resampling schemes satisfy the asymptotic condition, where the bias decreases monotonically with increasing sample size (T) and block length. MBB consistently produces lower bias than NBB due to its more intensive use of overlapping data, which effectively reduces boundary effects. Although inference on autoregressive parameters can be accurate, inference on spatial autoregressive parameters yields less satisfactory results, indicating the limitations of time blocks in capturing complex spatial dependencies. Increasing the number of replications above B=100 does not significantly improve the precision of the variance estimate, indicating computational efficiency at that threshold. The t-test results confirm that there is no statistically significant difference in performance between NBB and MBB. Nevertheless, MBB is more recommended for practical applications due to its higher information density and better estimation stability.

On Vertex-Degree-Based Topological Indices of Cayley Digraphs of Rectangular Groups and Their Role as Molecular Descriptors

Denpong Pongpipat, Nuttawoot Nupo — Fri, 13 Mar 2026 00:00:00 +0000

Let Cay(S,A) be the Cayley digraph of a finite rectangular group S with connection set A. We derive explicit formulas for several vertex-degree–based topological indices of these digraphs, including the Randić, Zagreb, sum-connectivity, geometric–arithmetic, atom–bond connectivity, and harmonic indices. The computations are reduced to Cayley digraphs of right groups, which simplifies the analysis. The underlying graphs are shown to be isomorphic to the hydrogen–included molecular graphs of cycloalkanes C_nH_2n. We prove that all considered indices depend linearly on the ring size n, exhibit stable growth, and differ only in their growth rates. Comparisons between related graph models illustrate the dependence of these indices on the underlying structure and support their interpretation as molecular descriptors, with possible relevance to QSAR/QSPR studies.

Potency of Leaf Water Extract Karamunting (Rhodomyrtus tomentosa) for Enhancing GLUT4 Translocation in Diabetic Rats

Fri, 13 Mar 2026 00:00:00 +0000

Insulin resistance and damage in the pancreas are associated with type 2 diabetes, which is a chronic disease affecting health, with 422 million people affected in 2016 and 1.5 million deaths related to diabetes in 2012. Several proinflammatory mediators, such as TNF-a andIL-6, may be involved in insulin resistance in T2DM. GLUT4 is one of the glucose transporters that help promote glucose uptake. GLUT4 activation is insulin-dependent in regulating glucose uptake. Karamunting (Rhodomyrtus tomentosa (Ait.) Hassk.) leaf water extract consists of alkaloids, flavonoids, triterpenoids, saponins, and tannins. This study proposes to investigate the potential of karamunting (R. tomentosa) leaf water extract to enhance glucose uptake by modulating GLUT4 translocation in the serum and skeletal muscle of diabetic rats. The dose variations used in this study were 100 mg/kgBW, 200 mg/kgBW, and 400 mg/kgBW. Based on the results, oral administration of karamunting water extract increases GLUT4 expression in serum. It increases GLUT4 mRNAlevels in the skeletal muscle of the diabetic rat. It decreases TNF-a and IL-6 expression, with a 100 mg/kg BW dosage being the most effective. Meanwhile, 100 mg/KgBW is the most effective dosage for decreasing HOMA IR. These results indicate that karamunting (R. tomentosa) leaf water is antidiabetic by lowering TNF-a, IL-6, and HOMA IR in diabetic rats while increasing GLUT4.

The Relation of Tribinomial Coefficients with Triangular, Catalan and Mersenne Number

Wamiliana, Desiana Putri, Notiragayu — Fri, 13 Mar 2026 00:00:00 +0000

Numbers are inseparable from mathematics. Each of these types of numbers has its own distinct definition and properties. Numbers are not only used in mathematics, but are also essential in other fields such as philosophy, technology, and science. Tribinomial coefficients, Catalan numbers, and Mersenne numbers are three types of numbers that has their own uniqueness and beauty. Tribinomial coefficients derived from triangular number using similar definition for binomial coefficients. Triangular numbers constitute a class of figurative numbers derived from the systematic arrangement of discrete units (such as dots) into the geometric configuration of an equilateral triangle. The Catalan numbers constitute a sequence of positive integers that emerge in numerous combinatorial enumeration problems. Formally, the n-th Catalan number is defined by the closed-form expression: $C_n = \frac{1}{n+1} \binom{2n}{n}= \frac{(2n)!}{(n+1)!n!}, n \in N$. Mersenne numbers are the numbers known in mathematics that also have their own beauty and uniqueness. When represented using binary, all Mersenne numbers are repeating 1s. The first eight Mersenne numbers are 1, 3, 7, 15, 31, 63, 127, 255, which are represented in binary as 1, 11, 111, 1111, 11111, 111111, 1111111, 11111111. In this study the relationship of Tribinomial coefficients with Catalan and Marsenne numbers will be disccused.