Search Results (90)

In this study, a multi-objective optimization framework based on an artificial neural network (ANN) was developed for an inlet perforated distributor plate in a 24S24P 10 kWh cylindrical lithium-ion battery module using immersion cooling. A combined Newman, Tiedeman, Gu and Kim with Computational Fluid Dynamics (NTGK-CFD) model was used to generate a symmetrically designed space by varying the input variables, including hole size A (mm), hole spacing ΔH (mm), and coolant mass flow rate V_in (kg/s). A three-level full factorial design was used to generate 27 cases, then CFD simulations were performed to provide a training data for the ANN model to predict the output variables, including maximum temperature T_max, maximum temperature difference ΔT_max, and pressure drop ΔP. The results show that the ANN model provides a reliable predictive model, capable of reproducing the thermal-hydraulic behavior of the immersion-cooled battery module with high fidelity via correlation coefficients R of 0.997 for all three output variables. In addition, Pareto-based optimization shows designs that balance cooling efficiency and pumping power. The selected optimal solution maintains T_max within the optimal range at 37.97 °C while reducing ΔP by up to 44%, providing a practical solution for large-scale battery module thermal management in EVs. Full article

Phthalic acid esters (PAEs) and polycyclic aromatic hydrocarbons (PAHs) are known to potentially impact both marine organisms and human health through the consumption of fish and seafood. In this study, the concentrations of 12 priority PAHs and 6 PAEs were analyzed in the tissues of 76 samples of five farmed fish species, including Litopenaeus vannamei (crustacean), Babylonia areolata, Marcia hiantina (mollusk), Trachinotus blochii, and Epinephelus lanceolatus (fish), collected from four coastal sites in Khanh Hoa province. Freeze-dried tissue was extracted using water bath ultrasonication with an acetone/n-hexane mixture. A triple quadrupole gas chromatograph–mass spectrometer (GC-MS/MS) was used for the analyses. The results showed that the total PAHs had low contamination levels. Among the PAEs, bis(2-ethylhexyl) phthalate (DEHP) exhibited the highest concentrations. The calculated hazard index (HI) for PAEs suggested no significant health risk. Six PAHs were detected, ranging from 9.14 µg kg⁻¹ in Pacific white shrimp to 47.34 µg kg⁻¹ in cockle. The incremental lifetime cancer risk (ILCR) values for PAHs in some samples exceeded the acceptable safety threshold. In the future, natural fish, environmental samples (seawater and marine sediment), and other information on natural conditions will be collected for analyses. This is the first report on the levels and health risks of PAEs and PAHs in farmed fishes along the Khanh Hoa coast. Full article

Avicennia marina, commonly known as the grey mangrove, is a salt-tolerant species widely distributed in coastal and estuarine ecosystems. Traditionally, it has been used in folk medicine to treat skin diseases, rheumatism, and ulcers due to its anti-inflammatory and antimicrobial properties. However, comprehensive studies on the chemical constituents and their pharmacological effects remain limited. The dried powder of the aerial parts of A. marina (3.6 kg) was successfully extracted three times with methanol (20 L × 3, each for 2 h) using a multifunctional ultrasonic cleaner operated at 25 °C with a 50% amplitude setting. In this study, the methanolic extract of the aerial parts of A. marina led to the isolation of eight compounds, including two previously unreported iridoid glycosides—avicenosides A and B (1 and 2)—and six known compounds: techtochrysin (3), 7,4′-di-O-methyl-apigenin (4), luteolin (5), kaempferol (6), trans-caffeic acid (7), and 3,4-dihydroxybenzoic acid (8). Their chemical structures were elucidated using nuclear magnetic resonance (NMR) spectroscopy and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) and compared with previously published data. Moreover, the absolute configuration of the sugar moieties in the new compounds was also identified. All isolated compounds were evaluated for their cytotoxicity against HepG2 and A549 cancer cell lines. The results indicate potential cytotoxicity of the secondary metabolites from A. marina and provide evidence of their promising role as lead compounds for the development of novel anticancer agents. Full article

This study employs advanced numerical simulation to investigate the influence of shelf temperature on the freeze-drying kinetics and product quality of Cordyceps militaris. Emphasis is placed on the glass transition and structural collapse mechanisms during the primary drying stage. A detailed computational model was developed to predict temperature profiles, glass transition temperature, collapse temperature, and moisture distribution under varying process conditions. Simulation results indicate that maintaining the shelf temperature below 10 °C minimizes the risk of structural collapse and volume shrinkage while improving drying efficiency and product stability. Based on the model, an optimal freeze-drying protocol is proposed: shelf heating at 0 °C, condenser plate at −32 °C, and chamber pressure at 35 Pa. Experimental validation confirmed the feasibility of this regime, yielding a shrinkage of 9.52%, a color difference (ΔE) of 4.86, water activity of 0.364 ± 0.018, and a rehydration ratio of 55.14 ± 0.789%. Key bioactive compounds, including adenosine and cordycepin, were well preserved. These findings underscore the critical role of simulation in process design and optimization, contributing to the development of efficient and high-quality freeze-dried functional food products. Full article

Background: Hypoxia and immune components significantly shape the tumor microenvironment and influence prognosis and immunotherapy response in gastric cancer (GC). This study aimed to develop hypoxia- and immune-related gene signatures for prognostic evaluation in GC. Methods: Transcriptomic data from TCGA-STAD were integrated with hypoxia- and immune-related genes from InnateDB and MSigDB. A prognostic gene signature was constructed using Cox regression analyses and validated on an independent GSE84437 cohort and single-cell RNA dataset. We further analyzed immune cell infiltration, molecular characteristics of different risk groups, and their association with immunotherapy response. Single-cell RNA-seq data from the TISCH database were used to explore gene expression patterns across cell types. Results: Five genes (TGFB3, INHA, SERPINE1, GPC3, SRPX) were identified. The risk score effectively stratified patients by prognosis, with the high-risk group showing lower overall survival and lower T-cell expression. The gene signature had an association with immune suppression, ARID1A mutation, EMT features, and poorer response to immunotherapy. Gene signature, especially SRPX was enriched in fibroblasts. Conclusions: We developed a robust hypoxia- and immune-related gene signature that predicts prognosis and may help guide immunotherapy strategies for GC patients. Full article

Small-scale inshore fisheries significantly contribute to the total landing volumes and have an important role in Vietnamese socioeconomic development, food security, livelihoods, and social well-being. The setnet fishery has been used throughout coastal communities of Vietnam for many decades. Being a passive fishing gear, the catch efficiency of setnet depends on various conditions such as fish density, season, oceanography, environment, and others. However, very little information exists about the relationship between catch rates and national conditions. Recognizing this research gap, this study examined the effect of temporal and environmental conditions on the catch rates of the narrow-barred Spanish mackerel (Scomberomorus commerson) setnet fishery using long-term data from 2005 to 2016. Overall, the catch of narrow-barred Spanish mackerel decreased over the course of the study. The generalized additive model (GAM) showed that catch rates were significantly affected by sea surface temperature (SST), which peaked at 27 °C. After this temperature point, the catch rates significantly decreased. Temporal variables also contributed to the catch variation. The setnet caught the highest yield in April and May, and more fish were caught during periods of low nightlight intensity than during high illuminated periods. Our study contributes to the understanding of critical factors affecting the catch rates of valuable species, which helps to determine the optimal fishing process of the setnet fishery within the shifting of marine heatwaves. Full article

The Po Nagar Towers (Thap Ba) complex, an iconic heritage site of Cham culture and a nationally recognized special relic, has stood in Nhatrang, Vietnam, for over a thousand years. We report here a preliminary analysis of original ancient Cham bricks from the Po Nagar Towers using a combination of appropriate characterization techniques, including X-ray fluorescence (XRF), X-ray diffraction (XRD), Raman micro-spectroscopy, thermal dilatometry, compressive strength testing, and water sorption. Mechanical properties and firing temperatures of the ancient bricks have been determined to support the discussion on the likely technology used to make them. Specifically, they were made from clay, sand, plagioclases/feldspar, and grog mixed with intentionally added carbon precursor (charcoal powder), then fired at temperatures between 800 °C and 1000 °C to form lightweight bricks with a mass density of 1.3–1.6 kg/dm³ and an open porosity of 18–25%. The ancient Cham bricks have their texture and porosity to meet the requirements of the thin rubbing joint technique in tower construction and to contribute to the carvability and durability of Cham towers. A comparison is made with the bricks for tower restoration during the 2000s. Full article

Contract farming has become a sustainable strategy in agriculture around the world. Formal farming contract in pig production is one of the priorities of the Vietnamese Government for livestock development. Due to the differences in husbandry methods, a comparison of the technical efficiency between contract and noncontract pig farms has not been studied in Vietnam yet. This study attempts to do so and proposes implications for the sustainable development of pig production in Vietnam. In this study, we surveyed 201 pig farms (63 contract farms and 138 noncontract farms) in Hanoi, Vietnam, and applied data envelopment analysis (DEA) with a meta-frontier. Under group frontiers, the technical efficiency of the contract and noncontract farms are 96.11% and 88.64%, respectively. However, the meta-technology ratios of the two groups are 82.30% and 99.99%, respectively, which means that contract farms’ technical efficiency is lower than noncontract farms. An interesting finding is that although the technical efficiency of contract farms is lower than noncontract farms, their annual pig income is significantly higher, making contract farming attractive to farmers. Results of Tobit regression models showed that land rent is one of the important factors that reduce the technical efficiency of both contract and noncontract farms. This result implies that the Vietnamese government should revise the land limit policy so that farms can own more land. Another finding is that the high feed price reduces the technical efficiency of noncontract farms. The policy implication from this finding is that the Vietnamese government should develop domestic raw material areas for feed production to lessen the dependence on imported raw materials from abroad, which contributes to reducing the feed prices in Vietnam. Full article

On 5 November 2020, a poisoning event involving four people by the consumption of moray eel occurred in Khanh Hoa Province, Viet Nam, with signs indicative of ciguatera. The remaining moray portion was confiscated for identification of causative species and responsible toxins. The phylogenetic study based on COX1 identified the moray as Gymnothorax javanicus Bleeker (1859). Out of 17 marine lipophilic toxins (MLPs) that were analyzed using LC-MS/MS, only Pacific ciguatoxin-1 (P-CTX-1) was detected in the moray’s flesh at 1.30 ± 0.004 ng/g ww, while no toxin was found in the skin. The N2a assay’s ciguatoxicities in the skin and flesh were 0.69 ± 0.075 and 2.49 ± 0.216 ng P-CTX-1/g ww equivalent, respectively. In the N2a assay, the P-CTX-1 amount in the moray flesh was 1.9 times greater than that determined by LC-MS/MS, indicating the presence of additional sodium channel activators or a matrix effect. The P-CTX-1 amount in the moray flesh was at a level that generates major ciguatera poisoning (CP) symptoms in humans (1.0 ng/g P-CTX-1), makes sense given that four consumers experienced the onset of poisoning symptoms. This study is significant for the management of seafood safety since it is the first scientific report on the species and toxin in a moray causing ciguatera in Viet Nam. Full article

Ecosystem-based adaptation (EbA) has been widely recognized as the key strategy for supporting farmers in adapting to climate change. The success of EbA requires a cohesive alignment from the national level to community implementation. However, harmonized efforts from central governments to local farmers remain underexplored in the literature on climate change and adaptation, especially in the context of mountainous areas of Vietnam. This study applied multiple qualitative research methods, including 12 key informant interviews, six focus group discussions, and 18 in-depth interviews to explore the varying perspectives of EbA between government officials and farmers, and how these perspectives influence their involvement in governmental initiatives. Using matrix coding visualization in NVIVO, this study revealed notable differences in perceptions of EbA between government officials and farmers, which in turn impact EbA practices at the commune level. This study also found factors affecting EbA practices, including knowledge, economic priorities, institutional support, labor shortages, limited market access, and funding inadequacies. The policy implications drawn from this study are necessary for bridging top-down policy with local realities, to ensure the sustainability and effectiveness of EbA. Furthermore, this paper contributes to the EbA literature by highlighting the need for context-specific adaptation strategies to enhance the effectiveness and inclusivity of EbA practices in vulnerable communities. Full article

D-2-hydroxyacid dehydrogenases (2HADHs) catalyze the reversible reaction of 2-ketocarboxylic acid to the corresponding (R)-2-hydroxycarboxylic acids using NAD(P)H cofactor. As the preference of the cofactor and substrate varies among homologs, biochemical characterization is required to understand this enzyme. Here, we analyzed the biochemical properties of Bacillus subtilis glyoxylate reductase/hydroxypyruvate reductase (BsGRHPR), which catalyzes the reduction of both glyoxylate (EC 1.1.1.26) and hydroxypyruvate (EC 1.1.1.81). Enzyme kinetics showed a preference for hydroxypyruvate over glyoxylate, with a seven-fold higher specificity constant. In addition, BsGRHPR displayed a strict preference for NADPH over NADH as a cofactor. The crystal structures of BsGRHPR in complex with formate were determined in the presence and absence of the cofactor at near-atomic resolution. Structural comparisons revealed conformational changes upon cofactor binding and key residues, such as Asp80, R157, R179, R239, Asp263, and Arg296. In addition, substrate-binding analysis highlighted conserved residues, including Val77, Gly78, His287, and S290. Our structures suggest that Glu137, His287, Ser290, and Arg296 serve as gatekeepers at the entrance of the tunnel. This comprehensive characterization of BsGRHPR elucidates its substrate specificity, cofactor preference, and catalytic mechanism, contributing to a broader understanding of GRHPR family enzymes, with potential implications for metabolic engineering applications. Full article

This study examines the effects of implementing sustainable strategies in operations on the abnormal stock returns of companies listed on the Vietnamese stock market under uncertain conditions, using an event study and difference-in-differences analysis. Daily trading data were obtained from 107 companies listed on the Vietnamese stock market from 2 January 2020 to 31 March 2020 (~6313 observations included in the sampling). Of these, 41/107 (38.3%) and 66/107 (61.7%) did and did not implement sustainability strategies in their operations, respectively. The feasible generalized least-squares regression model indicated a positive impact of the implementation of sustainable strategies in operations on abnormal stock returns of the companies during the COVID-19 pandemic (p < 0.01 in the context of the COVID-19 pandemic). The results underline the implementation of sustainability strategies in the operations of companies as a critical tool to mitigate damage under uncertain conditions, enhance resilience, and achieve long-term competitive advantages. Full article

In the context of increasing interest in ecosystem-based adaptation (EbA), there remains a paucity of discussion regarding the transition from perception to practice in aiding farmer households to adapt to climate change (CC) while maintaining the provision of essential ecosystem services. Thus, this study aims to explore policymakers’ and local people’s perceptions, from thinking about the implementation of EbA strategies to responding to CC in current and future agricultural production and forestry in upland Thua Thien Hue province, Vietnam. This study has adopted the Model of Private Proactive Adaptation to CC to investigate the perceptions of EbA among various administrative and household levels through in-depth interviews and focus group discussion methods. Our findings indicate a significant relationship between the perceptions and understanding of EbA among policymakers and farmer households, and the adoption of EbA practices. Many EbA practices are already well-established and have demonstrated their ability to enhance ecosystem services provision, adaptation benefits, and livelihood and food security. These benefits are crucial for helping farmer households to adapt to CC. However, current financial, technical, and market constraints hinder the broader adoption of these practices. Therefore, to increase adaptive capacity to CC and upscale EbA practices, EbA interventions must consider technical, financial, and market aspects. Furthermore, it is essential to provide evidence from both scientific and practical perspectives and disseminate information on EbA practices to encourage broader adoption by local farmers. In addition, supportive policies from various departmental and agency levels are necessary for managers in the agricultural and forest sectors as well as households to recognize EbA as a vital strategy for developing agriculture and forestry in a manner that is sustainable and resilient to CC. Full article

The genotype-by-environment interaction (G × E) might have crucial impacts on the performance and fitness of agricultural species, such as Pacific whiteleg shrimp (Litopenaeus vannamei). This study explores how enhancements in management practices can counteract G × E effects on growth traits. We analyzed a selectively bred population of whiteleg shrimp spanning the latest two generations, encompassing 259 full-sib and half-sib families with 40,862 individual shrimp, measured for body weight and total length. Our analysis revealed moderate genetic correlations (0.60–0.65) between trait expressions in pond and tank environments, a significant improvement compared to earlier generations. Employing the average information-restricted maximum likelihood (REML) approach in mixed model analysis showed significant differences in heritability (h²) estimates between the two environments; however, the extent of these differences varied by trait (h² = 0.68 in pond vs. 0.37 in tank for weight, and 0.41 vs. 0.67 for length). Our results indicate that G × E effects on growth traits in this population of L. vannamei were moderate but biologically significant. Consistent with our previous estimates in this population, genetic correlations between body weight and total length remained high (close to one) in pond and tank environments. The present findings collectively demonstrate that management improvements targeting stocking density, aeration, water quality, feeds, and feeding regimes mitigated the G × E effects on two economically significant traits in this population of whiteleg shrimp. Full article