Dong Thap University Journal of Science: Natural Sciences Issue
Tạp chí của Trường Đại học Đồng Tháp
Evaluating the ability to enrich the polyphenol content in the lotus seed epicarp extract by macroporous resin
The lotus seed epicarp is a byproduct of lotus seed processing, mostly discarded or dried for use as fuel. Polyphenols, a group of compounds with antioxidant properties that protect cells from damage caused by free radicals, have been found in the lotus seed epicarp. An effective enrichment method is required to enhance the total polyphenol content in lotus seed epicarp extract while utilizing natural medicinal resources for disease prevention. Currently, macroporous resins have been much concerned due to their potential applications in the adsorption, isolation and purification of bioactive compounds such as phenolics, alkaloids, flavonoids, tannins, and saponins from plant extracts. With a simple implementation and operation process, low cost, avoidance of toxic solvents, and the ability to be reused, the enrichment of polyphenols using macroporous resins is considered a feasible and promising approach. This study evaluates several factors affecting the polyphenol enrichment process using macroporous resin. The results show that HPD 750 resin exhibits good adsorption and desorption capacities, with values of 18.96 0.16 mg/g and 68.56 1.28 %, respectively, under the following conditions: extract concentration of 5,000 ppm, adsorption time of 30 minutes, desorption solvent of 96% ethanol, and desorption time of 180 minutes. The polyphenol content in the extract before and after enrichment was determined to be 363.89 6.27 and 517.48 4.73 mg GAE/g. From these results, it can be concluded that the polyphenol enrichment method using macroporous resin is effective.
Copyright (c) 2026 Dong Thap University Journal of Science: Natural Sciences Issue
Optimization of waste paper pretreatment using response surface methodology for enhanced cellulose recovery efficiency
This study focuses on optimizing the pretreatment process of waste cardboard using sodium hydroxide (NaOH) to recover high-purity cellulose for biological and industrial applications. Response Surface Methodology (RSM) combined with Central Composite Design (CCD) was used to investigate and optimize technological parameters, including NaOH concentration, temperature, treatment time, and the NaOH-to-paper ratio. A bleaching step using sodium hypochlorite (NaClO) was subsequently applied to improve cellulose purity. The optimal conditions were found at a temperature of 100°C, treatment time of 3.5 hours, 2.5% NaOH concentration, and a NaOH-to-paper ratio of 70/1 mL/g, resulting in a maximum impurity removal efficiency of 40.347%. The treated samples were characterized by field-emission scanning electron microscopy (FE-SEM) to observe surface morphology and Fourier-transform infrared spectroscopy (FTIR) to identify changes in chemical functional groups. This study contributes to enhancing paper recycling efficiency, minimizing solid waste, and promoting environmentally friendly and sustainable paper production processes. Recovered cellulose can be applied in the production of biofilms, biomedical materials, composite materials, or bio-adsorbent products, thereby increasing the utilization value of recycled materials and advancing the circular economy model.
Study the effects of processing and packaging on the quality of gluten-free bread supplemented with breadfruit flour
This study developed a gluten-free bread recipy from gluten-free ingredients such as breadfruit flour, rice flour, soybean flour, corn tarch, potato starch, sugar, yeast, butter, milk, salt, water, cooking oil, xanthan gum and maltodextrin. The effects of breadfruit flour supplementation (0%, 10%, 15%, and 20%), xanthan gum (0%, 0.5%, 0.7%, and 0.9%), butter (0%, 15%, 20%, and 25%), yeast (1.5%, 3%, and 4.5%), and fermentation time (30 minutes, 60 minutes, and 90 minutes) on several quality criterias of the bread were investigated. The results showed that supplementing with 15% breadfruit flour, 0.7% xanthan gum, 20% butter, 3% yeast, and fermenting for 60 minutes produced a product with a moisture content of 31.31%, hardness of 1.96 N, crust and crumb lightness (L*) of 50.83 and 59.51, crust and crumb yellowness of 20.27 and 5.17, fiber content of 1.92%, mineral content of 0.42%, and the highest sensory value. The product was stored in polypropylene (PP) packaging for 2 days showing acceptable microbial growth and retained relatively stable quality.
Cluster Isotherm Analysis and Quantum Structural Optimization of L-Proline on MKN-SWCNT S1 carbon nanotubes
This study constructed the adsorption isotherm of L-proline on MKN-SWCNT S1 single-walled carbon nanotubes was constructed. The cluster adsorption model was used to analyze the experimental isotherm. The results showed that L-proline was adsorbed in the form of a monomer and a cluster composed of 6–7 monomers. Quantum chemical methods were used to optimize the structure and determine the basic parameters of the adsorption system. The results showed that the most likely mechanism for immobilizing amino acids on the carbon nanotube surface is Van der Waals interaction.
Research on modification of rubber wood (Hevea brasiliensis) using potassium silicate (K2SiO3)
Potassium silicate (K₂SiO₃), also known as liquid glass, when used to treat wood, creates a series of physical changes in the wood structure that enhance moisture resistance, and thereby, it improves the physical properties of the wood. This experimental study evaluated the water absorption capacity and volumetric swelling rate of Rubberwood (Hevea brasiliensis) after treatment with potassium silicate (K₂SiO₃) over different treatment durations. The results showed the influence of these factors through the following regression correlation equations:Water absorption function: Y₁ = 54.9 – 10.21·x₁ – 0.7765·x₂ – 0.49·x₁·x₂ – 0.5979·x₁² + 1.2·x₂², Volumetric swelling rate function:Y₂ = 7.23 – 1.02·x₁ – 0.6936·x₂ + 0.265·x₁·x₂ + 0.2359·x₁² + 0.115·x₂² The optimal result for reducing water absorption in rubberwood was achieved with a potassium silicate concentration of X₁ = 1,414 (N = 27,07%) and a treatment duration of X₂ = 0.348 (T = 3,348 hours). Meanwhile, the optimal result for minimizing the volumetric swelling rate was identified at a potassium silicate concentration of X₁ = –0,43 (N = 17,85%) and a treatment duration of X₂ = 0,619 (T = 3,619 hours).
Adsoption of voltatile organic compounds on activated carbon surface: a DFT study
In this work, the shapes of stable structures for organic compounds adsorption on activated carbon (AC) surface at pure- and Fe/Zn-doped states are obtained at the PBEPBE/6-31G(d) level of theory. The binding between sites of molecules and surface is focused on ring center and functional groups. For doped surfaces (Fe@AC, Zn@AC), the stable interactions are formed favorably at Fe/Zn sites and functional groups. The adsorption energy values of molecules on surfaces range from -6.2 to -8.3 kJ.mol-1 for AC and from -7.4 to -49.3 kJ.mol-1 for Zn@AC and -166.3 to -292.7 kJ.mol-1 for Fe@AC. Noticeably, AIM and NBO results indicate the existence and strength of intermolecular interactions upon complexation. The H‧‧‧C*/π weak forces play an important role in the configuration strength for AC. Besides, the O‧‧‧Fe/Zn electrostatic interactions with partly covalent nature contribute significantly to the stability of configurations for Fe/Zn doped AC. The addition of Fe onto AC enhances the adsorption ability of organic molecules as compared to Zn-doping.
Effect of stocking density on growth and survival of Thai frogs (Rana tigerina) reared under antibiotic-free protocol
The study “Effect of stocking density on growth and survival of Thai frogs (Rana tigerina) reared under antibiotic-free protocol” was conducted over a period of 60 days. The objective of the study was to determine the appropriate stocking density of Rana tigerina to increase production per unit area without affecting growth, survival rate and feed efficiency of frogs. Frog with initial body weight of 8,0 g/frog were raised in a cement tank with an area of ​​2m2 with 4 densities of 80, 100, 120 and 140 frog/m2. Frog were fed twice a day at adlibitum rate with 30% protein pellet. No antibiotics were used during the experiment. Regularly supplement the biological product (Bacillus sp.) into the feed once a week to enhance the frogs' immunity, using a dosage of 3 g/kg of feed. During the experiment, any frog showing signs of illness will be isolated from the breeding tank. Research results showed that frogs raised using antibiotic-free processes at a stocking density of 100 frogs/m2 gave the best results in terms of growth, survival rate, feed conversion ratio (FCR), and profitability. After 60 days of rearing, the average weight of the frogs was 155.6±6.42 g/frog, FCR was 1.14±0.02, the survival rate was 88.3±1.45% and the profit was 138,697 VND/m2.
Spin-1 Ising model with biquadratic exchange interaction in an external magnetic field: A theoretical study within the mean-field approximation
The spin-1 Ising model with bilinear and biquadratic exchange interactions in an external magnetic field is studied on a simple two-dimensional square lattice within the mean-field approximation. The obtained results show the existence of dipolar or quadrupolar order, depending on the variation in the strength of the two types of interactions in the absence of a magnetic field. Furthermore, the influence of the external magnetic field on these order is also investigated in detail. These results are analyzed through the presence of spin-1 states with nonzero magnetic moment (i.e., Sz = \pm 1) and zero magnetic moment (i.e., Sz = 0).
Coulomb drag in double bilayer graphene with inhomogenous background dielectric
This paper presents the results of studying Coulomb drag resistivity in double bilayer graphene under the influence of an inhomogeneous substrate dielectric. Using the random phase approximation (RPA), this study determines the system's polarization function and the frequency-dependent dielectric function, thereby calculating the Coulomb drag resistivity. The results indicate that the Coulomb drag resistivity increases with increasing temperature but decreases rapidly as the interlayer distance between the bilayer graphene sheets increases. Notably, with an inhomogeneous background dielectric, the Coulomb drag resistivity is significantly higher than that in the case of a homogeneous dielectric. This phenomenon arises from the modification of the Coulomb interaction potential between electrons in the two layers due to the inhomogeneity of the background dielectric. Furthermore, calculations reveal that at different temperatures, the Coulomb drag resistivity tends to decrease with increasing carrier density. However, a distinct difference emerges between two cases: small and large interlayer separations. Under a small interlayer separation, the Coulomb drag resistivity is more strongly influenced by carrier density and temperature. These findings provide further insights into the role of the inhomogeneous background dielectric in double bilayer graphene systems and suggest potential applications for next-generation graphene-based electronic devices.
Studying some applications of the Lambert function in elementary mathematics
This paper first introduces the Lambert function and discuss some of its fundamental properties. Next, it establishes a process for computing or approximating the value of the Lambert function at a given point. Furthermore, it presents several applications of the Lambert function in constructing and solving problems in elementary mathematics, including solving exponential equations and determining the limits of sequences. Finally, a collection of illustrative problems are provided to demonstrate these applications.
Investigation of α -Glucosidase inhibitory potential for diabetes treatment and development of filter tea bags from mai vang leaves
From fresh leaves of Mai vang (Ochna integerrima (Lour.) Merr.), collected in Dong Thap province, the processing process has been completed to create tea bags with a weight of 2 g/pack. First, the materials are selected, washed, then roasted and stored in a filter bag according to the net weight of 2 g/package. On the other hand, the tea of the filter bag is infused with boiling water at 100°C to obtain the extract, which was then freeze-dried to yield an aqueous extract used for activity evaluation.. Water overhead survey of Mai vang leaf tea showed very good α-glucosidase inhibitory activity with an IC50 of 65.46±1.27 μg/mL, while the value of the acarbose control sample was 134.50 μg/mL under the same test conditions. These results confirm the inhibitory potential and therapeutic applicability of Mai vang leaves in the treatment of diabetes.
Copyright (c) 2025 Dong Thap University Journal of Science: Natural Sciences Issue
Investigation of antioxidant activity and pancreatic lipase inhibitory potential of Ipomoea batatas L. extracts
This study evaluated the antioxidant activity and pancreatic lipase inhibitory potential of ethanol extracts from three parts (stem, leaf, and sprout) of sweet potato (Ipomoea batatas L.). The ethanol extracts were quantified for total polyphenol content (TPC) and total flavonoid content (TFC), and their antioxidant activities were assessed using DPPH, ABTS, and ferric reducing antioxidant power (FRAP) assays. Pancreatic lipase inhibitory activity was determined in vitro using p-nitrophenyl laurate as a substrate, and further validated in vivo in Mus musculus mice through a lipid absorption test. The leaf extract demonstrated superior results compared to the stem and sprout extracts in terms of both compound content and antioxidant activity (TPC: 279.4 ± 1.83 mg GAE/g; TFC: 85.7 ± 1.21 mg QE/g; IC₅₀ ABTS: 47.33 ± 0.72 µg/mL; IC₅₀ DPPH: 80.86 ± 3.13 µg/mL). Notably, the leaf extract also exhibited the strongest pancreatic lipase inhibitory activity (IC₅₀ = 134.68 ± 1.27 µg/mL), being only approximately 2.3 times less potent than the positive control, orlistat. In vivo experiments confirmed that the leaf extract significantly reduced plasma triglyceride levels in mice after lipid emulsion administration, comparable to the effect of orlistat. These findings indicate that sweet potato leaves are a potential plant source rich in polyphenol and flavonoid compounds with considerable antioxidant and lipid-digesting enzyme inhibitory activities, providing a scientific basis for the development of formulations to aid in the management of obesity and lipid metabolism disorders.
Teaching parametric equations of a line in space using Toulmin’s model integrated with analogical reasoning
Reviewing relevant documents on reasoning abilities, teaching methods, and the requirements to teaching the topic "Coordinate method in space" under the current general education program, this study proposes a pedagogical solution to organize teaching activities on the topic "Parametric equations of a straight line" (Math 12) towards developing ability. On a clear lesson plan and a set of detailed assessment criteria, the study demonstrates the potential of this integration in fostering students' mathematical reasoning ability when transforming their perception of "Parametric equations of a straight line" from two dimensions to three dimensions. Although experiments have not been conducted, this approach provides teachers with a teaching process with a solid theoretical basis, contributing to supporting the process of fostering students' mathematical reasoning ability. However, it is necessary to conduct pedagogical experiments to verify the effectiveness of the model, and at the same time consider adjusting and expanding its application to other mathematical topics.
Social impact of climate change on coastal communities in Vinh Long province
This study applies the social impact factor (SIF) to assess the extent of climate change (CC) impacts on vulnerable communities in the coastal areas of Vinh Long province. The research approach combined spatial statistical interpolation using kriging with the analytic hierarchy process (AHP) to construct and quantify the SIF, a metric that reflects social vulnerability. The SIF which includes three main components: exposure (E), sensitivity (S), and adaptive capacity (AC). The research findings indicated that the social impact of climate change tends to increase, with approximately 63% of surveyed households falling within the SIF range of -0.08 to 0.21, corresponding to a high level of social impact.. The group experiencing very high social impacts (SIF ranging from 0.25 to 0.47) accounts for about 6% of the total surveyed households, representing those with the lowest capacity to adapt to climate change impacts. In addition, the results of spatial interpolation analysis indicate that most of the rice cultivation areas were affected by saltwater intrusion, with Tra Cu Commune (15,515 ha) being the most severely impacted, while Truong Long Hoa ward and Long Huu Commune was not affected as rice is not cultivated in this area. These results demonstrated that climate change has contributed to increasing social vulnerability, particularly among disadvantaged population groups with low adaptive capacity.
Effects of Kinetin, NAA, and IBA concentration on in vitro shoot proliferation and root induction of Philodendron billietiae
The study on the effects of Kinetin, NAA, and IBA on in vitro shoot multiplication and root formation of Philodendron billietiae was conducted to determine the suitable basal MS media supplemented with concentrations of Kinetin, NAA and IBA for in vitro culture. The experiments were carried out at the Tissue and Cell Technology Lab, College of Agriculture, Can Tho University, comprised of three experiments: The effect of Kinetin and NAA concentrations on the in vitro shoot regeneration stage; The effect of IBA concentration on the in vitro root formation of P. billietiae; and Observation on the survival rate of P. billietiae plantlets under nursery conditions. The results showed that: (i) During the shoot multiplication stage, MS medium supplemented with Kinetin 2 mg/L and NAA 0.1 mg/L yielded the best results at 10 weeks after cultured (3.61 shoots per explant); (ii) MS medium supplemented with 2 mg/L IBA resulted in a 100% root formation rate at 6 weeks after cultured; (iii) During the acclimatization phase, P. billietiae plantlets showed a high survival rate (100%) under both covered and uncovered with plastic bag. The plantlets adapted and developed well after 4 weeks acclimatized and could be transferred to natural condition.
On generalized second – order asymptotic derivatives and application in parametric vector optimization problems
This paper deals with generalized second-order asymptotic derivatives of frontier and solution maps in parametric vector optimization problems. Under some mild conditions, we obtain some formulas for computing generalized second-order asymptotic derivatives of frontier and solution maps, respectively.
Synthesis and investigation of antimicrobial activity of bioplastic films from Persicaria odorata L. extract
This study aims to synthesize a bioplastic film from sweet potato starch in combination with EtOH extract of Persicaria odorata Lour., showing the antimicrobial properties and biodegradability. The methodology includes investigating optimal conditions for bioplastic film synthesis combined with glycerol as a plasticizer and P. odorata extract. The bioplastic films were evaluated for sensory analysis, mechanical-physical properties, chemical characteristics, antibacterial and anti-mold activities, and biodegradation capacity. Results revealed that bioplastic films containing 15% glycerol and 20% extract exhibited potential sensory characteristics with a thickness of 0.24 mm, tensile strength of 8.42 N, and lower water absorption than films without plant extract. SEM analysis showed that extract-containing films had smoother surfaces with fewer pores. Notably, bioplastic films supplemented with 20% plant extract demonstrated inhibitory activity against Escherichia coli O157:H7 and Staphylococcus aureus, preventing mold growth. Additionally, these films exhibited favorable biodegradation properties, with mass reduction exceeding 30% after 6 days and complete decomposition after 18 days when buried in the soil. This study has demonstrated the potential to applying bioplastic films derived from sweet potato starch combined with P. odorata extract as a solution to mitigate the environmental impact of plastic waste while enhancing food safety.
Botanical study, polyphenol quantification and biological activity of Cassia fistula flower extracts
Cassia fistula is widely distributed in Vietnam; however, studies on the botany, chemical composition, and biological activities of its flowers remain limited. This study aimed to investigate the botanical characteristics, conduct a preliminary phytochemical screening, and evaluate the antioxidant and α-glucosidase inhibitory activities of C. fistula flowers. Microscopic anatomical features were observed using a double-staining method. Preliminary phytochemical screening was carried out using a modified Cuiley method. Total polyphenol content was quantified using the Folin–Ciocalteu reagent and UV-Vis spectrophotometry. Antioxidant activity was evaluated based on DPPH free radical scavenging assay, while α-glucosidase inhibitory activity was assessed according to the method of Hua Qiang Dong (2012).The results revealed that C. fistula possesses characteristic botanical and chemical features of the genus Cassia, family Caesalpinioideae. The polyphenol content decreased in the order: FICF70 (26,29 ± 0,07 mg GAE/g dry material), FICF50 (24,02 ± 0,10 mg GAE/g dry material), FICF00 (23,63 ± 0,26 mg GAE/g dry material), and FICF96 (11,10 ± 0,25 mg GAE/g dry material). The DPPH assay showed that antioxidant activity followed the same decreasing order: FICF70 > FICF50 > FICF00 > FICF96. All extracts demonstrated significant α-glucosidase inhibitory activity, with FICF96, FICF70, and FICF50 showing similar IC₅₀ values, all lower than that of the aqueous extract. These findings provide additional scientific data on C. fistula flowers and contribute to enhancing the therapeutic potential of Vietnamese medicinal plants.
Investigation of antibacterial activities of wells-dawson polyoxometalates
The study was conducted to investigate the antibacterial activity of 8 Wells-Dawson polyoxometalate (POM) compounds including a-K6P2W18O62.14H20 and b-K6P2W18O62.19H2O (P2W18), K10[a2-K6P2W17O61].20H2O (P2W17), K15H[CeIV(a2-P2W17O61)2].25H2O (CeIVWD 1:2), K15H[Zr(a2-P2W17O61)2].25H2O (ZrWD 1:2), Na14[Zr4(P2W16O59)2 (m3-O)2(OH)2(H2O)4].57H2O (ZrWD 4:2), a2-K8P2W17O61(CoII.H2O).16H2O (CoWD 1:1), a2-K8P2W17O61(NiII.H2O).17H2O (NiWD 1:1) và a2-K8P2W17O61(CuII.H2O).16H2O (CuWD 1:1) against 5 bacterial strains including Escherichia coli, Salmonella spp., Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus. The antibacterial activity of all 8 Wells-Dawson POM compounds was examined by the agar well diffusion method and/or the 2-fold serial dilution method. The experimental results showed that for 3 bacterial species Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, all 8 WD-POM compounds showed antibacterial activity. Among them, P2W18 showed the best antibacterial activity against all 3 bacterial strains and the minimum inhibitory concentration (MIC) values ​​were determined to be 0.1875 mM, 6, 3, and 6 times lower than the MIC values ​​of the tetracycline positive control, respectively. For Escherichia coli, only P2W18showed antibacterial ability with an average inhibition zone of 7,33±0,58 mm, about 4 times smaller than that of the tetracycline positive control. For Salmonella spp., all 8 Wells-Dawson POM compounds did not show antibacterial ability.
Deep learning-based interatomic potentials for predicting thermodynamic properties of two-dimensional Ge/MoS2 systems
This study presents the development and application of machine learning interatomic potentials based on neural networks for simulating two-dimensional materials, specifically monolayer Germanene, monolayer MoS2, and the heterostructure Ge/MoS2. Using first-principles molecular dynamics data, the ML models were trained via the DeePMD-kit framework to predict formation energies and atomic forces. The results demonstrate that machine learning can efficiently capture energy landscapes with high accuracy, even with limited training data. In contrast, predictions of moderately accurate atomic forces exhibit higher absolute errors, particularly affecting phonon calculations. Optimal neural network configurations were identified for each material system, enabling enhanced learning performance. This work confirms the potential of machine learning, particularly deep learning-based potentials, in accelerating thermodynamic modeling of 2D heterostructures with significantly reduced computational cost compared to traditional ab initio methods. Additionally, it underscores the need for more diverse datasets to enhance the reliability of force prediction in dynamical simulations.
Designing and evaluating a scale of mathematical problem-solving ability of grade 6 students on the content "Fracrational value of a number"
Developing competencies, including mathematical problem-solving ones, is an inevitable trend in education. Assessing students' competencies accurately will be an important basis for proposing appropriate teaching methods as well as evaluating the effectiveness of those methods. This study designed a rubric for assessing written tests on mathematical problem-solving competencies. Through the assessment of 66 teachers and experiments on 132 students, the study proposed a good rubric for assessment, and also made recommendations for designing similar rubrics in the future.
Investigation of the chemical composition, antioxidant and antibacterial activities of ethanolic extracts of Ficus hirta var. roxburghii (Miq.) King
The initial study investigated the chemical composition and biological activity of Ficus hirta var. roxburghii (Miq.) King. Quatitative analysis revealed the presence of alkaloids, flavonoids, steroids, triterpenoids, and tannins. Stem extract exhibited high levels of total polyphenols content (39.18 mg GAE/g), flavonoids (73.62 mg QE/g), and tannins (71.86 mg CE/g) compared to leaf extract, correlating with strong antioxidant activity (EC50 values of 192.24 µg/mL for DPPH and 60.73 µg/mL for ABTS•+; Abs0.5 values of 305.24 µg/mL for RP and 226.91 µg/mL for TAC). Conversely, leaf extract contained higher alkaloid content (125.56 mg AE/g) and inhibited Salmonella sp. with a MIC of 625 µg/mL. This differential distribution of bioactive compounds suggests potential for developing specialized natural medicinal products.
Classification of banana stages using microwave spectroscopy by machine learning
In the food industry, the need to assess and predict the ripening process of fruits plays an important role in optimizing storage and transportation strategies, ensuring the product quality when reaching consumers. The study proposes a method using microwave spectrum based on vector network analyzer combined with machine learning models. This method is used to evaluate among numerous machine learning models and predict the number of days required for an unripe banana to turn to semi ripe and then ripe banana. Data is collected through scattering parameters, including reflection parameter S11 and transmission parameter S21, in the frequency range from 1 GHz to 5 GHz. The S-parameters are processed, analyzed and extracted characteristic data and fed into the machine learning models to perform the comparison and prediction process.
Investigating chemical composition and antibacterial activity of Catharanthus roseus (L.) G. Don
This study provides a preliminary evaluation of the antibacterial activity of different leaf extracts from Catharanthus roseus (L.) G. Don and identifies the most bioactive extract for subsequent phytochemical investigation. Among the tested extracts, the dichloromethane extract exhibited significant antibacterial activity against Vibrio sp. and Aeromonas caviae, two major pathogenic bacteria in aquaculture. Notably, the dichloromethane extract showed strong inhibition against Vibrio sp., with an inhibition zone diameter of 17.97±0.47 mm at a concentration of 128 µg/mL. Phytochemical analysis of the dichloromethane extract using nuclear magnetic resonance (1D, 2D-NMR) spectroscopy, in combination with comparison to published data, led to three compounds identified: apigenin (1), vindoline (2), and oleanolic acid (3). The results highlight the potential of C. roseus leaves as a promising natural source of potent antibacterial agents.
On the relationship between solutions of a class of one-dimensional stochastic differential equations
The main purpose of this paper is to explore the relationship between the solutions of a class of stochastic differential equations in the cases with and without external forces. The central idea is to transform the stochastic differential equations into ordinary differential equations in order to simplify the analysis of their solution properties. This transformation is then combined with Itô's formula to estimate the bounds of the first and second moments of the diffusion process described by the considered stochastic differential equations.
Characterizing cosmic muon flux as a function of zenith angle using Geiger-Müller coincidence setup
The study uses a low-cost, dual Geiger-Müller (GM) tubes coincidence detection device in an outdoor environment to evaluate the relationship between cosmic muon flux on zenith angle. Coincidence occurrences decreased from 484 counts at vertical alignment to 47 counts at horizontal alignment, with zenith angles of 0°, 30°, 45°, 60°, and 90°. Under normal values at sea level, the measured directional muon flux at 0° was 1.301 muons/cm²/min. An exponent of n = 1.063 ± 0.107 was obtained by fitting the angular dependency to a cosine power law via a Bayesian Markov Chain Monte Carlo (MCMC) approach. The result indicates a qualitative agreement with a cosine-based angular distribution under practical constraints, despite the fact that this value is less than the theoretical expectation (n ≈ 2). The setup achieved a Noise Rejection Ratio (NRR) of 0.373% and a Directional Index (DI) of 0.804, indicating moderate directional selectivity and noise suppression. This study demonstrates the viability of Geiger-Müller detectors in basic cosmic ray research and educational contexts.
Studying morphological characteristics, anatomical structure of Melaleuca species, Callistemon citrinus and acacia auriculiformis
Common morphology characteristics among the species Melaleuca cajuputi subsp. cajuputi, Melaleuca cajuputi subsp. cumingiana, Melaleuca alternifolia, Callistemon citrinus, and Acacia auriculiformis often cause confusion among them and complicate their application. This study aims to characterize the morphological features and anatomical structure of five species based on the plant morphological analysis method. The leaf anatomical specimens at the sites of stems, veins, and tips of leaves were performed by horizontal slicing, and dyeing carmin aluné–vert d’iode. Furthermore, the anatomy of flowers was analyzed based on their components at the pre-flowering stage. The results showed an identical morphology between these species. However, certain morphological differences are present such as the color of the bark, leaf size, flower color, the type of flower pre-anthesis. Differences in anatomical structure, namely the number of secretory cavities in the leaves and the color of the stamens. At a 95% confidence level, Acacia auriculiformis exhibits the largest leaf size, while Melaleuca alternifolia presents the smallest. Each species is characterized by distinct floral coloration: Melaleuca cajuputi subsp. cajuputi displays pale greenish-white flowers, Melaleuca cajuputi subsp. cumingiana has ivory-white flowers, Callistemon citrinus exhibits bright red flowers, and Acacia auriculiformis produces vivid yellow flowers. Notably, Acacia auriculiformis leaves lack secretory cavities, a distinguishing feature compared to members of the Myrtaceae family. These species can be differentiated based on external morphological characteristics, with floral color serving as one of the most distinctive and easily recognizable traits.
Investigating antioxidant extraction from Receptaculum Nelumbinis
Receptaculum Nelumbinis, also known as Lotus receptacle, is a byproduct of the seed-harvesting process of Nelumbo nucifera. It is dried and used as fuel, aesthetic decoration or for cooking drinking water. Extracts from Lotus receptacle contain several active compounds such as alkaloids, polyphenols, flavonoids, glycosides, tannins, steroids, and saponins. Among these, polyphenols are a compound of strong antioxidant activity. In this study, the extraction method and solvent were investigated to increase the polyphenol content. The polyphenol and flavonoid contents and the antioxidant activity of the Lotus receptacle extract were also evaluated. The results showed that the highest yield of the extract (34,06%) was obtained using the reflux method with 70% ethanol as the solvent, a 90-minute extraction time, and a temperature of 70oC. The chemical composition of the Lotus receptacle extract included polyphenols, alkaloids, flavonoids, terpenoids, tannins, and coumarins. The extract’s flavonoid and polyphenol contents were determined to be 361,86 ± 11,16 mg QE/g and 585,12 ± 6,01 mg GAE/g, respectively. The Lotus receptacle extract also exhibited strong antioxidant activity, as demonstrated by its ability to scavenge DPPH and ABTS•+ free radicals and its reducing power (RP), with corresponding EC50 values of 11,10 ± 0,14 μg/mL, 6,78 ± 0,52 μg/mL and 56,05 ± 0,73 μg/mL, respectively. These results suggest that the Lotus receptacle is a potential source of antioxidant phytochemicals.
Copyright (c) 2023 Dong Thap University Journal of Science: Natural Sciences Issue
Investigating total flavonoid content and antioxidance of ethanol extracts from Ruellia simplex C.WRIGHT
This study investigated the natural compounds with biological activity in Ruellia simplex C.Wright flower such as steroids, flavonoids, alkaloids, saponins, tannins, and terpenoids, etc. The total flavonoid content as well as the antioxidant capacity of two ethanol extracts (E96 and E80) extracted from Ruellia simplex C.Wright flower were also studied. Results indicated that Ruellia simplex C.Wright flowers contained flavonoids, alkaloids, tannins and terpenoids, but not steroid or saponin compounds. Total flavonoid content in E96 and E80 were 7.13 and 0.98 mg QE/g extract, respectively. The antioxidant capacity studied by DPPH free radical neutralization method showed that the percentage of 50% inhibition of DPPH free radicals (IC50) of E96 and E80 were 0.089 and 0.242 mg/mL, respectively. The reference standard was ascorbic acid (IC50=0.02 mg/mL).
Effect of lead (Pb) in soils on the growth and lead accumulation of water spinach (Ipomoea aquatica)
This research aimed to assess the effect of lead (Pb) concentration in soils on the growth and development of water spinach (Ipomoea aquatica) and Pb accumulation in the plant. Water spinach was cultivated in soil pots for 40 days, including one control treatment with uncontaminated soil and six treatments with Pb-contaminated soils (85.6 - 1053.3 mg/kg). After 40 days, fresh root and shoot weights were measured. Also, the content of chlorophyll a and chlorophyll b in leaves, and Pb concentration in shoots were determined. The results showed that when water spinach was cultivated in soils with Pb levels of up to 328.4 mg Pb/kg, the fresh root and shoot weights, the contents of chlorophyll a and chlorophyll b in leaves were statistically similar to those observed in the control treatment. However, in soils with Pb concentrations of ³ 520.4 mg Pb/kg, the fresh root and shoot weights and the contents of chlorophyll a and chlorophyll b significantly decreased compared to the control treatment. For Pb uptake by the plant, the bioaccumulation of Pb in water spinach shoots increased with increasing Pb concentrations in the soils. The Pb concentration in the edible parts of water spinach harvested from soils contaminated with 148.3 - 1053.3 mg Pb/kg exceeded 2 - 65-fold the maximum permissible level for Pb in fresh vegetables as regulated by the Ministry of Health. Therefore, the Pb levels in soils cultivating water spinach must be controlled to ensure food safety and protect human health.