Vietnam Journal of Science, Technology and Engineering - C

Enhanced baseline correction for Raman spectroscopy using a hybrid deep learning approach

Vu Duong*, Pham Hong Minh — 2025-12-25

This research introduces an enhanced baseline correction method for Raman spectroscopy, combining a hybrid deep learning approach with traditional techniques such as polynomial fitting, Gaussian functions, and other nonlinear components. The proposed method significantly improves the signal-to-noise ratio (SNR), achieving up to a tenfold increase over raw spectra and outperforming conventional algorithms such as Imodpoly (polynomial fitting) and AirPLS (Penalised least squares). With a processing time of just 1.07 seconds, the method is well-suited for realtime applications in portable Raman spectroscopy systems. This improvement is critical in Raman spectroscopy, where background noise often obscures weak spectral features, making a high SNR essential for accurate chemical analysis. The rapid processing capability allows for immediate correction of spectral data, ensuring efficient and accurate analysis in practical applications. Thus, this hybrid approach establishes itself as a robust and effective solution for real-time Raman spectroscopy.

Hydrogen spillover on Ni-, Pd- and Pt-doped ZnO ultra-thin films: A density functional theory study

Ho Viet Thang* — 2025-12-25

Hydrogen spillover plays an important role in heterogeneous catalytic reactions, such as syngas production, hydrogen production, and CO₂conversion. Among metal oxide materials, ZnO films stand out as promising candidates for hydrogen storage, though their pure form has limitations for certain applications. In this study, the hydrogen spillover on Ni, Pd, and Pt-doped ZnO ultra-thin films is investigated by employing the DFT+U method. To this end, the spillover and non-spillover structures of hydrogen are considered, and their electronic structures are evaluated in undoped and doped ZnO ultra-thin films. The calculated results show that the Ni, Pd, and Pt-doped ZnO ultrathin films can alter the electronic properties of the undoped material from insulating to metallic characteristics. While hydrogen spillover cannot occur on undoped ZnO films, it can proceed with 50% coverage of H atoms on Pd-doped ZnO films and 100% hydrogen coverage on Ni- and Pt-doped ZnO films. This study paves the way for synthesising ZnO-based catalysts for hydrogen storage, catalysis, and other desired applications.

Structural distortion and temperature-dependent carrier transport of Al-, Ga-, and In-doped ZnO thin films

2025-12-25

ZnO-based films hold significant potential for optoelectronic applications, such as transparent electrodes and absorbance layers, as well as thermoelectric applications. Doping with Al, Ga, and In has attracted considerable attention for controlling the carrier transport properties of these films. Pure ZnO, Al-doped ZnO, Ga-doped ZnO, and In-doped ZnO films, each with a similar doping ratio of 1 wt%, were successfully deposited on glass substrates using the magnetron sputtering technique. X-ray diffraction was employed to confirm the ZnO structure, while temperature-dependent Hall-effect measurements were utilised to investigate the dependence of carrier transport on temperature. The results indicate that Al and Ga dopants enhance conductivity more effectively than In. This
may be attributed to a substantial increase in carrier concentration when Al and Ga are doped into ZnO-based films as the temperature rises. Conversely, the In-doped ZnO film exhibits an increase in mobility, resulting in enhanced conductivity. These findings underscore the intricate interplay between doping elements, measurement temperature, and the electrical behaviour in ZnO films, offering valuable insights for further optimisation and application in various electronic and optoelectronic devices. This research opens the possibility of controlling the properties of ZnO films for applications at different operating temperatures.

Energy efficiency evaluation of a centralised wastewater treatment plant in an industrial zone of former Binh Duong province, Vietnam

Vinh Thi Nguyen, Le Hung Anh* — 2025-12-25

Efficient energy utilisation in wastewater treatment plants is a significant challenge for management, particularly in developing countries. This study presents an integrated approach combining energy auditing, real-time monitoring, and energy assessment to optimise industrial wastewater treatment plant operations in Vietnam, with a treatment capacity of under 4,000 m³/day. The research methodology employs an energy audit approach combined with daily measurements, analysing the plant’s operational data for 2023. Results indicate that the aerobic tank consumes the most energy (56.1% of total plant consumption). Wastewater pumps, blowers, mixers, and sludge pumps consume a substantial amount of electricity (77.6% of total electricity consumption). The average specific energy consumption is 0.93 kWh/m³ of treated wastewater, 10.58 kWh/kg CODremoved, and 59.12 kWh/kg TNremoved, which are 15-20% higher than international benchmarks for similar-scale facilities. Based on the analysis, we propose optimisation strategies: (1) improving operating conditions and flexibility; (2) optimising the blower system for aerobic tanks; (3) upgrading to energy-efficient pumps; (4) enhancing lighting, automatic monitoring, and office systems; (5) integrating renewable energy sources. These interventions could reduce energy consumption by 25-30% while maintaining treatment efficiency. The research findings will enhance the plant’s energy efficiency, reduce operational costs, and support Vietnam’s goal of achieving net-zero emissions by 2050.

Multi-stage drying processes in Clitoria ternatea flower extracts: A method to intensify anthocyanins for botanical dye production

Nhan Kiet Tran*, Ngoc Minh Thu Trinh — 2025-12-25

This study presents an optimised multi-stage drying process for Clitoria ternatea (butterfly pea) flower extracts to enhance anthocyanin concentration for sustainable botanical dye production, addressing the need for nontoxic and environmentally friendly dyeing methods. This method preserves anthocyanins through pre-treatment (cleaning, alkaline stabilisation, and blanching) before a sequential drying process at 70, 60, and 50°C. Each stage gradually reduced moisture while preserving pigment stability. Anthocyanin levels were measured via UV-Vis spectrophotometry, and colour stability was tested under natural sunlight to mimic real-world conditions. The optimised protocol increased anthocyanin concentration by 40% (from 45 to 63 mg/l) while maintaining moisture content at 5-7%, ensuring long-term stability. Notably, the treated extracts retained vibrant colour under sunlight with only minor fading, proving the method’s viability for dye production. Additionally, the study introduces a scalable, eco-friendly process for producing stable anthocyanin dyes, promoting sustainable practices in textiles, cosmetics, and food production while meeting the demand for environmentally friendly alternatives.

A new dichloro-substituted benzyl alcohol derivative from the rhizomes of Curculigo capitulata (Lour.) Kuntze

2025-12-25

Curculigo capitulata (Lour.) Kuntze’s rhizomes have been utilised in traditional medicine for the treatment of various diseases, such as kidney stones, high blood pressure, nephritis, and cystitis. To date, there has been limited research on its chemical constituents in Vietnam. A phytochemical investigation of the ethyl acetate extract from C. capitulata’s rhizomes led to the isolation of five compounds, including a novel dichlorophenolic derivative, named capitulatol A (1), and four known compounds: O-orsellinaldehyde (2), cinnamic acid (3), orcinol (4), and orcinol glucoside (5). Their structures were elucidated using 1D and 2D nuclear magnetic resonance (NMR) spectroscopic and high-resolution electrospray ionisation-mass spectrometry (HRESI-MS) data, along with comparisons to
previously published references. Compound 1 has not been described before, while compounds (2-4) have been isolated from this plant for the first time. These results indicate that phenolics and phenolic glucosides are the main components, which can serve as significant markers for the chemotaxonomy of the herb. Moreover, this chemical information will enhance our understanding of this plant, both in Vietnam and globally. Furthermore, the findings can be applied to further research in pharmacology and clinical medicine in the future.

Study on the reuse of high-silica by-product from Lionas Metals Plant to partially replace cement in concrete production

Dang-Nguyen Nguyen∗ — 2025-12-25

This study investigates the reuse of high-silica by-product (HSB) from the Lionas Metals Plant as a partial replacement for cement in concrete production. Four mixtures with 0, 10, 20, and 30% cement replacement by HSB were designed using the absolute volume method at a fixed water-to-binder ratio of 0.45. The study evaluated the effects of HSB on concrete properties, including fresh and dry unit weights (UW), water absorption (WA), compressive strength (CS), ultrasonic pulse velocity (UPV), thermal conductivity (TC), and rapid chloride ion penetration (RCPT). Results showed that increasing the HSB content led to a reduction in both fresh and dry UWs. WA decreased with longer curing times and higher HSB content, while resistance to chloride ion penetration improved significantly. The HSB content resulted in higher CS and UPV while reducing WA, TC, and RCPT. Higher HSB content resulted in greater CS and durability, with the 30% HSB mixture demonstrating outstanding 28-day performance: a maximum CS of 65.04 MPa, the highest UPV of 4902 m/s, the lowest WA of 1.14%, a reduced TC of 1.96 W/(m×K), and an extremely low RCPT value of 179 Coulombs. Microstructural analysis supported these observations. The findings demonstrate HSB’s effectiveness in improving concrete performance and confirm its viability for sustainable concrete production.

Isolation and identification of IAA-producing rhizobacteria from Robusta coffee plantations in Dak Nong province

2025-12-25

This study aimed to isolate and identify indole-3-acetic acid (IAA)-producing microorganisms from the rhizosphere of Robusta coffee plantations in Dak Nong province, Vietnam. A total of 539 microbial strains (319 bacteria, 140 fungi, and 80 actinomycetes) were isolated and screened for IAA production using the Salkowski colourimetric method. Key findings revealed that 32.0% of bacterial isolates and 33.6% of fungal isolates demonstrated IAA production above 1.0 μg/ml, with 9 bacterial strains and 4 fungal strains producing more than 50.0 μg/ml of IAA. In contrast, only 3.8% of actinomycetes showed minimal activity (1.0-10.0 μg/ml). Key findings of this study are the identification of strain DN13_B03, which exhibited the highest IAA production (178 μg/ml), confirmed by Highperformance liquid chromatography (HPLC) analysis with a distinct peak matching the standard IAA sample. Based on morphological characteristics (yellowish-white colonies, Gram-positive rod-shaped cells) and 16S rRNA gene sequencing, we identified DN13_B03 as Priestia megaterium. Optimisation studies revealed that maximum IAA production (205 μg/ml) was achieved with 0.5% L-tryptophan, at pH 6.0, within a broad temperature range (25-40°C). The remarkable IAA-producing capability of this indigenous strain presents significant potential for developing region-specific biofertilisers to enhance sustainable coffee cultivation in Vietnam.

Effect of dilution ratio, storage time and storage temperature on goat sperm quality

Tran Thi Thanh Khuong*, Nguyen Thi Bich Thuy — 2025-12-25

Artificial insemination is a technique that facilitates the rapid development of livestock herds, including goats, improves breeds, and produces healthy, high-yield livestock. The liquid storage of semen is an effective method for short-term preservation to support artificial insemination. The Mekong delta offers natural conditions favourable for goat farming. This study aimed to determine the optimal temperature, dilution ratio, and storage duration for preserving goat sperm in Tris-Citrate-Glucose (TCG) medium. The experiment comprised six treatments, each repeated eight times. After collection, semen samples were diluted in TCG medium at ratios of 1:25, 1:250, and 1:2500, and stored at two temperatures: 5°C and 15°C. Sperm quality was evaluated at six specific preservation intervals: 0, 6, 12, 48, and 72 hours. The results indicated that goat sperm quality was best after 72 hours of storage when diluted at a ratio of 1:25 and stored at 15°C. Specifically, after 72 hours of storage at 15°C, samples with a dilution ratio of 1:250 recorded overall motility, progressive motility, viability, and membrane integrity rates of 70.10, 44.79, 72.33, and 48.50%, respectively. In conclusion, the optimal conditions for preserving goat sperm were achieved with a dilution ratio of 1:250 at 15°C for up to 72 hours.

Study on the causal relationship and optimise the extraction procedure of herbal preparation from Herba Mimosae pudicae, Folium Erythrinae variegatae, Cortex Cinnamomi iners, and Herba et radix Scopariae

Oanh - Hoang Hua* — 2025-12-25

Herbal preparations from four herbs - Mimosa pudica, Erythrina variegata, Scoparia dulcis, and Cinnamomum iners - exhibit sedative effects, treat insomnia, and effectively reduce anxiety and depression. The chemical components present in these medicinal herbs, such as mimosine and coixol, are biologically active substances. This study investigates the causal relationship and optimises the extraction procedure to achieve higher extraction efficiency. Fourteen experiments were designed using Design-Expert software to evaluate the influence of three independent variables (number of extractions, extraction time, and solvent-to-material ratio) on four dependent variables (extraction efficiency of mimosine, extraction efficiency of coixol, total extraction efficiency, and production cost). The content of mimosine and coixol was determined using the high-performance liquid chromatography (HPLC) method. Data were utilised as input for Phasolpro RD 1.0 software to model and optimise the extraction procedure for the medicinal herbs in the formulation. The extraction process was optimised with a solvent-to-material ratio of 21:1, two extractions, and an extraction time of 2.03 hours. The optimised procedure provides a useful foundation
for improving extract quality and applying it as a semi-finished material for medicinal product production.

Investigating Palmatine’s inhibitory mechanism on type 2 diabetes via molecular docking

Do Thi Hang — 2025-12-25

Type 2 diabetes mellitus (T2DM) is the most common form, accounting for more than 90% of all individuals with diabetes worldwide. Currently, T2DM is on the rise and is increasingly affecting younger individuals, becoming a serious public health issue. Palmatine is a natural isoquinoline alkaloid belonging to the protoberberine group. The purpose of this study was to evaluate the anti-diabetic properties of Palmatine through molecular docking with several protein targets related to T2DM, such as α-amylase, pyruvate dehydrogenase kinase 4 (PDK4), α-glucosidase, protein tyrosine phosphatase 1B (PTP1B), aldose reductase (AKR1B1), and 11β-hydroxysteroid dehydrogenase (11β-HSD1). Lipinski’s rule of five was employed to assess the drug-like characteristics of Palmatine. The pharmacokinetic properties of Palmatine were evaluated using the pkCSM tool, which aids in predicting its absorption, distribution, metabolism, excretion, and toxicity (ADMET) profile. The oral bioavailability of Palmatine was assessed using the SwissADME tool. The results indicated that Palmatine inhibits 11β-HSD1 with the lowest binding energy (-8.4 kcal/mol). According to Lipinski’s analysis, Palmatine exhibits properties consistent with druglike behaviour. The predicted pharmacokinetic parameters suggest that this compound possesses excellent intestinal absorption. Furthermore, Palmatine demonstrated favourable oral bioavailability. Consequently, additional in vitro and in vivo research is necessary to further explore the potential of this compound as a future treatment for diabetes.

Efficacy of auricular acupuncture combined with electroacupuncture for chronic low back pain: A randomised controlled trial

Diem Huong Thi Nguyen — 2025-12-25

Chronic low back pain (CLBP) imposes significant medical treatment costs and leads to numerous serious health consequences. In recent years, non-pharmacological therapies have garnered increasing attention, particularly electroacupuncture (EA) and auricular acupuncture (AA). While considerable research has examined the efficacy of EA and AA in managing CLBP, it may be beneficial to investigate the impact of combining these approaches. This
study evaluated the efficacy of a combined AA and EA treatment for CLBP compared to EA alone. This randomised, double-blind, controlled trial allocated 80 patients into two groups: one receiving EA in conjunction with AA at the target points Shenmen (TF4), Lumbosacral Vertebrae (AH9), and Subcortex (AT4), and the other receiving EA with sham AA (AA applied at non-acupoint locations). Pain intensity, functional disability, and spinal mobility were assessed using the visual analogue scale (VAS), Oswestry disability index (ODI), and Schober index at baseline (T0), after 7 days (T7), and after 14 days (T14). While both groups exhibited improvement, the intervention group demonstrated a greater reduction in VAS scores (T14: 1.65±0.66 vs. 3.28±0.91, p<0.001) and ODI scores (T14:
13.98±1.43 vs. 17.45±1.74, p<0.001), alongside a significant increase in spinal flexibility (Schober index: 14.66±0.80 vs. 13.43±1.04, p<0.001). In conclusion, among patients with CLBP, the combination of AA and EA resulted in more effective pain relief and greater improvement in spinal function compared to EA alone.

Direct non-medical costs and influencing factors of patients with non-small cell lung cancer treated with targeted therapy: A cross-sectional study in Vietnam

Van Chinh Nguyen*, Huy Tuan Kiet Pham — 2025-12-25

To estimate the direct non-medical costs and related factors for patients with non-small cell lung cancer (NSCLC) with estimated glomerular filtration rate (EGFR) mutations who received first-line targeted therapy, a crosssectional study was conducted from October 2022 to December 2023. Interviews were conducted with 310 NSCLC patients at the Vietnam National Cancer Hospital in Tan Trieu. The mean total direct non-medical costs for NSCLC patients were VND 832,989 per month, accounting for 3.6% of the mean total costs and 29.6% of the average income of NSCLC patients. The highest proportion of patients incurred expenses for transportation (98.7%), meals (90.0%), and lodging (39.0%). Costs for transportation (VND 591,525, accounting for 71.0%), meals (VND
155,580, accounting for 18.7%), and lodging (VND 85,884, accounting for 10.3%) were reported. Meal and lodging costs increased with the duration of hospital visits (p<0.001). Factors such as residing in rural areas, frequency of caregivers, and duration of hospital visits were found to affect the direct non-medical costs of patients with EGFR-mutated NSCLC (p<0.05). Organisations and individuals should support NSCLC patients by offering free or discounted meals, lodging, and transportation. This assistance can help reduce the out-of-pocket burden on patients and prevent them from falling into poverty.

Development of sustained-release floating tablets of diltiazem hydrochloride

2025-12-25

Diltiazem hydrochloride (DTZ), utilised for cardiovascular conditions, possesses a short half-life, necessitating frequent dosing. To enhance compliance, sustained-release (SR) floating tablets were developed using a quality by design (QbD) approach. This study aimed to formulate DTZ 120 mg tablets, conforming to United States Pharmacopeia 2023 dissolution standards, at a batch size of 1000 tablets. Wet granulation was employed with hydrophilic polymers to control drug release, while gas-generating excipients were used to ensure buoyancy. Tablets were evaluated for floating characteristics, in vitro dissolution, and drug release mechanisms. Hydroxypropyl methylcellulose K100M controlled release (HPMC K100M CR), NaHCO₃, and PVP K30 significantly influenced output variables and were selected for the experimental design. The release rate of DTZ decreased with higher amounts of HPMC and NaHCO₃, while PVP had a minimal effect. The optimised formula included HPMC K100M CR (501.5 mg), NaHCO₃(244.8 mg), PVP K30 (32.4 mg), and other excipients. Tablets exhibited a floating lag time of less than 1 minute and a floating duration exceeding 30 hours. Dissolution results met United States Pharmacopeia
standards, showing values of 26.99±0.97% at 6 hours, 50.31±0.40% at 12 hours, and 91.46±1.92% at 30 hours. The manufacturing process for 1000 tablets per batch was established, and process parameters were investigated.

Identification of grain size and mineral distributions in the surface sediments of Red river estuaries in Vietnam

Bui Van Vuong — 2025-12-25

The mineral composition and grain size of 45 surface sediment samples from the estuaries of the Red River system were analysed to assess the dynamics and origin of the sediments. Five types of sediments are distributed in river mouths, which are coarse silt, very fine sand, very coarse silt, fine sand, and medium silt. The mineral contents in the sediment were as follows: quartz 46.0%, illite 18.3%, kaolinite 11.8%, chlorite 6.4%, feldspar 6.0%, goethite 4.4%, calcite 1.9%, gibbsite 1.7%, and amphibole 1.4%. Between grain size parameters and mineral compositions were positive and negative correlations. The positive correlations were between S0 and illite, kaolinite, goethite, calcite; between Md and quartz, feldspar, amphibole; between illite, kaolinite, chlorite, goethite together. The
negative correlations were between quartz, feldspar, Md with illite, kaolinite, chlorite; between goethite with quartz, feldspar, Md; between amphibole with kaolinite; between gibbsite with quartz; between S0 and Md, quartz, feldspar, amphibole. There were two sediment groups: Group 1 was weakly dynamic, and Group 2 was strongly dynamic. The minerals in the sediments were mainly continental, characterised by illite, kaolinite, chlorite, quartz, feldspar, and amphibole, with other sources, including precipitation and weathering, being limited.

TABLE OF CONTENTS IN 2025

DTL — 2025-12-25

TABLE OF CONTENTS IN 2025