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1. Exploration of a Model Thermoacoustic Turbogenerator with a Bidirectional Turbine

Author

Korobko Volodymyr, Serbin Serhiy, and Le Huu Cuong

Subjects
waste heat recovery, ship power plant, thermoacoustics, thermoacoustic engine, bidirectional turbine, Naval architecture. Shipbuilding. Marine engineering, VM1-989
Abstract

The utilisation of the thermal emissions of modern ship power plants requires the development and implementation of essentially new methods of using low-temperature waste heat. Thermoacoustic technologies are able to effectively use low-temperature and cryogenic heat resources with a potential difference of 500–111 K. Thermoacoustic heat machines (TAHMs) are characterised by high reliability, simplicity and environmental safety. The wide implementation of thermoacoustic energy-saving systems is hampered by the low specific power and the difficulties of directly producing mechanical work. An efficient approach to converting acoustic energy into mechanical work entails the utilisation of axial pulse bidirectional turbines within thermoacoustic heat engines. These thermoacoustic turbogenerators represent comprehensive systems that consist of thermoacoustic primary movers with an electric generator actuated by an axial-pulse bidirectional turbine. The development of such a thermoacoustic turbogenerator requires several fundamental issues to be solved. For this purpose, a suitable experimental setup and a 3D computational fluid dynamics (CFD) model of a thermoacoustic engine (TAE) with bidirectional turbines were created. The research program involved conducting physical experiments and the CFD modelling of processes in a TAE resonator with an installed bidirectional turbine. The boundary and initial conditions for CFD calculations were based on empirical data. The adequacy of the developed numerical model was substantiated by the results of physical experiments. The CFD results showed that the most significant energy losses in bidirectional turbines are manifested in the output grid of the turbine.

Published
2023
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6. Management Strategy for Seaports Aspiring to Green Logistical Goals of IMO: Technology and Policy Solutions

Author

Le Thanh Tuan, Nguyen Hoang Phuong, Rudzki Krzysztof, Rowiński Lech, Bui Viet Duc, Truong Thanh Hai, Le Huu Cuong, and Pham Nguyen Dang Khoa

Subjects
green seaport, management strategy, clean energy, decarbonization, sustainable maritime, Naval architecture. Shipbuilding. Marine engineering, VM1-989
Abstract

Recently, because of serious global challenges including the consumption of energy and climate change, there has been an increase in interest in the environmental effect of port operations and expansion. More interestingly, a strategic tendency in seaport advancement has been to manage the seaport system using a model which balances environmental volatility and economic development demands. An energy efficient management system is regarded as being vital for meeting the strict rules aimed at reducing the environmental pollution caused by port facility activities. Moreover, the enhanced supervision of port system operating methods and technical resolutions for energy utilisation also raise significant issues. In addition, low-carbon ports, as well as green port models, are becoming increasingly popular in seafaring nations. This study comprises a comprehensive assessment of operational methods, cutting-edge technologies for sustainable generation, storage, and transformation of energy, as well as systems of smart grid management, to develop a green seaport system, obtaining optimum operational efficiency and environmental protection. It is thought that using a holistic method and adaptive management, based on a framework of sustainable and green energy, could stimulate creative thinking, consensus building, and cooperation, as well as streamline the regulatory demands associated with port energy management. Although several aspects of sustainability and green energy could increase initial expenditure, they might result in significant life cycle savings due to decreased consumption of energy and output of emissions, as well as reduced operational and maintenance expenses.

Published
2023
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8. Improving the prediction of biochar production from various biomass sources through the implementation of eXplainable machine learning approaches.

Author

Nguyen, Van Giao, Sharma, Prabhakar, Ağbulut, Ümit, Le, Huu Son, Cao, Dao Nam, Dzida, Marek, Osman, Sameh M., Le, Huu Cuong, and Tran, Viet Dung

Subjects
CLEAN energy, CLIMATE change & health, SUSTAINABILITY, ENERGY consumption, ARTIFICIAL intelligence
Abstract

Examining the game-changing possibilities of explainable machine learning techniques, this study explores the fast-growing area of biochar production prediction. The paper demonstrates how recent advances in sensitivity analysis methodology, optimization of training hyperparameters, and state-of-the-art ensemble techniques have greatly simplified and enhanced the forecasting of biochar output and composition from various biomass sources. The study argues that white-box models, which are more open and comprehensible, are crucial for biochar prediction in light of the increasing suspicion of black-box models. Accurate forecasts are guaranteed by these explainable AI systems, which also give detailed explanations of the mechanisms generating the outcomes. For prediction models to gain confidence and for biochar production processes to enable informed decision-making, there must be an emphasis on interpretability and openness. The paper comprehensively synthesizes the most critical features of biochar prediction by a rigorous assessment of current literature and relies on the authors' own experience. Explainable machine learning techniques encourage ecologically responsible decision-making by improving forecast accuracy and transparency. Biochar is positioned as a crucial participant in solving global concerns connected to soil health and climate change, and this ultimately contributes to the wider aims of environmental sustainability and renewable energy consumption. [ABSTRACT FROM AUTHOR]

Published
2024
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17. Insights into the bacterial community composition of farmed Caulerpa lentillifera: A comparison between contrasting health states

Author

Germán A. Kopprio, Nguyen D. Luyen, Le Huu Cuong, Tran Mai Duc, Anna Fricke, Andreas Kunzmann, Le Mai Huong, and Astrid Gärdes

Subjects
16S rRNA gene, aquaculture, green caviar, sea grape, seaweed, Vietnam, Microbiology, QR1-502
Abstract

Abstract The bacterial communities of Caulerpa lentillifera were studied during an outbreak of an unknown disease in a sea grape farm from Vietnam. Clear differences between healthy and diseased cases were observed at the order, genus, and Operational Taxonomic Unit (OTU) level. A richer diversity was detected in the diseased thalli of C. lentillifera, as well as the dominance of the orders Flavobacteriales (phylum Bacteroidetes) and Phycisphaerales (Planctomycetes). Aquibacter, Winogradskyella, and other OTUs of the family Flavobacteriaceae were hypothesized as detrimental bacteria, this family comprises some well‐known seaweed pathogens. Phycisphaera together with other Planctomycetes and Woeseia were probably saprophytes of C. lentillifera. The Rhodobacteraceae and Rhodovulum dominated the bacterial community composition of healthy C. lentillifera. The likely beneficial role of Bradyrhizobium, Paracoccus, and Brevundimonas strains on nutrient cycling and phytohormone production was discussed. The bleaching of diseased C. lentillifera might not only be associated with pathogens but also with an oxidative response. This study offers pioneering insights on the co‐occurrence of C. lentillifera‐attached bacteria, potential detrimental or beneficial microbes, and a baseline for understanding the C. lentillifera holobiont. Further applied and basic research is urgently needed on C. lentillifera microbiome, shotgun metagenomic, metatranscriptomic, and metabolomic studies as well as bioactivity assays are recommended.

Published
2021
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21. Carrageenophyte-attached and planktonic bacterial communities in two distinct bays of Vietnam: Eutrophication indicators and insights on ice-ice disease

Author

Germán A. Kopprio, Le Huu Cuong, Nguyen Dinh Luyen, Tran Mai Duc, Tran Hong Ha, Le Mai Huong, and Astrid Gärdes

Subjects
16S rRNA diversity, Kappaphycus, Euchema, Pollution, Vibrio, Ecology, QH540-549.5
Abstract

The composition of the bacterial community of carrageenophyte-attached and planktonic bacteria was studied in two bays of Vietnam with contrasting anthropogenic inputs to assess their role as ecological indicators. Clear differences (~73% dissimilarity) between carrageenophyte-attached bacteria and bacterioplankton were detected in terms of genus composition: mainly Agaribacter, Ruegeria, Alteromonas, the Pir4 lineage and Vibrio for the carrageenophytes and Candidatus Actinomarina, HIMB 11, NS groups and SAR clades for the bacterioplankton. The copiotrophic nature, potential for complex-polymer degradation, and ability to form and defend biofilms were common features inferred for the carrageenophyte-attached microbiome. Significant differences between the bays were detected in the concentration of most inorganic nutrients. More eutrophic conditions and presumptive wastewater pollution in Cam Ranh (CR) bay were primarily indicated by the dominance of Rubripirellula, Leptobacterium, Hypnocyclicus and Porphyrobacter and their correlations with phosphate. In terms of bacterioplankton, the influence of intensive aquaculture in CR bay was suggested by the dominance of the NS5 and NS4 marine groups, the SUP05 cluster, Flavobacteriaceae unclassified and SAR 11 clade III as well as their strong correlations with ammonium and phosphate. The link between silicate and other inorganic nutrients suggests freshwater input in CR bay. Arenicellaceae unclassified and Formosa were also potential indicators of eutrophication. Operational taxonomic units (OTUs) of Marinagarivorans, Cobetia, Vibrio, Alteromonas and Pseudoalteromonas were typical of the carrageenophytes showing ice-ice disease symptoms. Vibrio and Alteromonas were also common among healthy macroalgae, and differences at the OTU level suggested potential succession of species from the healthy to the diseased state. The probable beneficial roles of some bacteria, such as Ruegeria, Cutibacterium and unidentified members of the family Rhizobiaceae, were discussed. This study provides pioneering insights into the bacterial community composition of carrageenophytes and highlights their ecological value as strong indicators of the sources of organic matter, anthropogenic impacts and health status of marine systems.

Published
2021
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23. Lignin peroxidase from the white-rot fungus Lentinus squarrosulus MPN12 and its application in the biodegradation of synthetic dyes and lignin

Author

Vu Dinh Giap, Do Huu Nghi, Le Huu Cuong, and Dang Thu Quynh

Subjects
Environmental Engineering, Bioengineering, Waste Management and Disposal
Abstract

Lignin peroxidase (LiP), which has been studied extensively in white-rot basidiomycetes and their potential to degrade dyes from textile wastewater, plays a role in the biodegradation of lignin from pulp and paper industry wastewater, as well as agricultural waste. Lignin peroxidase (LsLiP) was successfully purified from the newly isolated Lentinus squarrosulus MPN12 with a 47.1-fold purification and a 15.7% yield. After 48 h-incubation, LsLiP was able to decolorize all tested dyes up to 92% for Acid Blue 62 (NY3), followed by Porocion Brilliant blue HGR (PB, 73.5%), Acid Blue 281 (NY5, 70.5%), Acid Blue 113 (IN13, 61%), Acid red 266 (NY7, 56%), and 34.5% for Acid red 299 (NY1), compared to the negative control with the heat-denatured enzyme. The biodegradation potential of LsLiP was further suggested by the change of lignin structure based on Fourier transform infrared (FTIR) analyses. Lignin structure was noticeably changed before and after LsLiP treatment, especially in the fingerprint regions (1600 to 1000 cm-1) and 2930 cm-1 corresponding to the stretching vibrations of various groups in lignin. Thus, LsLiP has potential application in both enzyme-based decolorization of synthetic dyes and lignin biodegradation.

Published
2022

25. Ensiffer sp. CNN3 -an indigenous bacterial strain in Vietnam has properties of plant growth promotion and organophosphorus degradation

Author

Hoang Kim Chi, Le Huu Cuong, Tran Thi Hong Ha, Nguyen Thu Ha, Luong Huu Thanh, Vu Thuy Nga, Le Mai Huong, and Tran Thi Nhu Hang

Subjects
Plant growth, Ensifer sp, Botany, food and beverages, Biology, Indigenous, Bacterial strain
Abstract

An indigenous effective bacterial strain has been isolated from soil samples of contaminated tea farming site in Northern Vietnam with chlorpyrifos degradability and plant growth promoting characteristics. The bacterial isolate was determined to belong to genus Ensifer (syn. Sinorhizobium), and its degrading property for OPP substrate chlorpyrifos in culture as well as in test soil were studied. The results open a prospect of applying the dual-effective bacterial strain in agriculture practices either to reduce the use of chemical fertilizer or to remediate OPP contaminated planting soils.

Published
2021

26. An extensive investigation on leveraging machine learning techniques for high-precision predictive modeling of CO2 emission.

Author

Nguyen, Van Giao, Duong, Xuan Quang, Nguyen, Lan Huong, Nguyen, Phuoc Quy Phong, Priya, Jayabal Chandra, Truong, Thanh Hai, Le, Huu Cuong, Pham, Nguyen Dang Khoa, and Nguyen, Xuan Phuong

Subjects
DEEP learning, MACHINE learning, ARTIFICIAL neural networks, OPTIMIZATION algorithms, PREDICTION models, CONVOLUTIONAL neural networks
Abstract

Predictive analytics utilizing machine learning algorithms play a pivotal role in various domains, including the profiling of carbon dioxide (CO2) emissions. This research paper delves into an extensive exploration of different algorithms, encompassing neural networks with diverse architectures, optimization, training, ensemble, and specialized algorithms. The primary objective of this research is to evaluate the efficacy of supervised and unsupervised algorithms, including Deep Belief Networks, Feed Forward Neural Networks, Gradient Boosting, and Regression, as well as Convolutional Neural Networks, Gaussian, Grey, and Markov models, and clustering and optimization algorithms. The study places particular emphasis on data-driven methodologies and cross-validation techniques with an evaluation of the learning models entailing comprehensive training, validation, and testing, employing evaluation metrics such as R2, MAE, and RMSE. The study employs correlation analysis to examine the relationship between input parameters and emission characteristics. The research highlights the advantageous attributes of these algorithms in accurately forecasting CO2 emissions, evaluating energy sources, improving prediction accuracy, and estimating emissions. Notably, deep learning, Artificial Neural Networks (ANN), and Support Vector Machines (SVM) demonstrate effectiveness across diverse industries, while the Modified Regularized Fast Orthogonal-Extreme Learning Machine (MRFO-ELM) algorithm optimizes predictions specifically related to coal chemical emissions. Hybrid techniques demonstrate accuracy in predicting carbon emissions and energy consumption, whereas gray prediction models provide reliable estimates even with limited data. However, it is important to acknowledge certain limitations, including data requirements, potential inaccuracies arising from complex factors, constraints faced by developing countries, and the impact of electric vehicle expansion on the power grid. To optimize models, a survey is conducted, involving customization of parameters and learning rates, while exploring various performance metrics to evaluate model accuracy. The research outcomes contribute to the effective monitoring of CO2 emissions in operational environments, thereby aiding executive decision-making processes. [ABSTRACT FROM AUTHOR]

Published
2023
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27. Effects of CeO2 nanoparticles on engine features, tribology behaviors, and environment.

Author

Le, Thanh Tuan, Venugopal, Inbanaathan Papla, Truong, Thanh Hai, Cao, Dao Nam, Le, Huu Cuong, and Nguyen, Xuan Phuong

Subjects
DIESEL motors, TRIBOLOGY, DIESEL fuels, NANOPARTICLE size, NANOPARTICLES, ENGINES
Abstract

Recently, scientists have developed a variety of approaches and techniques to boost the performance of engines and lower hazardous emissions. One method that has received a lot of interest is the employment of nanoparticles in fuels to address several drawbacks of fuels. Indeed, ceria (CeO2) nanoparticles are a common additive derived from fuel to lower particulate emissions discharged from diesel-powered engines. The preparation techniques and physicochemical features of biodiesel-originated fuels including CeO2 nanoparticles were thoroughly introduced in this review work. Also, the performance, combustion, and emission characteristics and tribological properties of diesel engines running on CeO2-included fuels were completely examined. Furthermore, this paper discussed the noticeable effects of CeO2 nanoparticles on human health and the environment in detail. Generally, adding CeO2 nanoparticles in terms of size ranging from 30–50 ppm into various biodiesel/diesel fuels showed positive impacts in terms of mitigating toxic emissions such as CO, HC, & smoke by the highest of about 94.98%, 91.16%, and 90.3% and improving diesel engine performance with a highest of about 31.25%, though their effects on the ecosystem and human health have been a contentious concern that needs handling in further investigations. The novelty of the current review is to provide comprehensive information on the ppm-specific use of CeO2 nanoparticles as a potential additive to blend with various biodiesel/diesel fuels aiming to improve various engine characteristics, tribological behavior, and environmental impact. [ABSTRACT FROM AUTHOR]

Published
2023
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28. Intracellular reactive oxygen species scavenging effect of fucosterol isolated from the brown alga Sargassum crassifolium in Vietnam

Author

Tran Thi Hong Ha, Do Huu Nghi, Le Mai Huong, Le Huu Cuong, Tran Thi Nhu Hang, Nguyen Thi Hong Van, Tran Mai Duc, and Hoang Kim Chi

Subjects
Chemistry, Botany, Intracellular reactive oxygen species, Fucosterol, Sargassum crassifolium, Scavenging
Abstract

Sargassum is a widely distributed marine brown algal genus in Vietnam and has been considered a source of diverse bioactive metabolites. In this study, S. crassifolium collected from South Central region of Vietnam was chemically studied and bioactively evaluated. Fucosterol was isolated and identified from the methanolic extract of the alga by means of chemical fractionation and spectral analysis and showed no cytotoxic effect in Hep-G2 cells at the observed concentrations. In vitro assay for intracellular reactive oxygen species by dichlorofluorescein method revealed a potent scavenging effect of the isolated compound. Accordingly, the level of intracellular reactive oxygen species induced by hydrogen peroxide (H2O2) was reduced by 71.66% with the treatment of fucosterol at 10 µg.ml-1. The results indicated the ability of algal fucosterol in diffusing into cells and preventing the production of different ROS compounds and further suggested the therapeutic potential against diseases caused by oxidative stress of natural metabolites from S. crassifolium in Vietnam.

Published
2020

29. Investigating the diversity of arbuscular mycorrhizal fungi from Gymnema sylvestre and Curcuma longa in Vietnam

Author

Tran Thi Nhu Hang, Tran Thi Hong Ha, Tran Ho Quang, Le Mai Huong, Hoang Kim Chi, Le Huu Cuong, Bui Anh Van, and Le Thi Hoang Yen

Subjects
fungi, Botany, Gymnema sylvestre, Biology, Curcuma, Arbuscular mycorrhizal fungi, biology.organism_classification
Abstract

Arbuscular mycorrhizal (AM) fungi are soil eukaryotes that belong to phylum Glomeromycota and have symbiosis with the vast majority of higher plants’ roots. AM fungi are believed to be coevolved with terrestrial plants, the abundance and diversity of AM fungal communities as a result are host plant dependent. A survey of AM fungi from the rhizospheres of medicinal plants in Northern Vietnam including gurma Gymnema sylvestre and turmeric Curcuma longa was carried out. From the extracted total DNAs of the medicinal plants’ rhizosphere soil samples, 35 mycorrhizal fungal species were identified by analyzing small subunit rRNA gene sequences. Result revealed that genus Glomus is the most abundant in the AM communities of G. sylvestre and C. longa, followed by Gigaspora and Acaulospora. Besides, AM species belonging to genera Scutellospora, Diversispora and Rhizophagus were observed in almost all rhizosphere soil samples. The spore counting by wet sieving and decanting method uncovered a variation in AM spore density of gurma and turmeric rhizosphere. In general, AM species were found more abundantly and more diverse in collected rhizome soil samples of C. longa (27 species belonging to 10 genera) than of G. sylvestre (17 species found belonging to 7 genera). The observed difference in AM communities of G. sylvestre and C. longa supports evidence for the dependence of AM fungal species on host plants, and indicates that AM fungi may have relation to the host plants’ secondary metabolite production.

Published
2020

31. Insights into the bacterial community composition of farmed Caulerpa lentillifera: A comparison between contrasting health states

Author

Anna Fricke, Andreas Kunzmann, Astrid Gärdes, Nguyen Dinh Luyen, Germán A. Kopprio, Le Mai Huong, Tran Mai Duc, and Le Huu Cuong

Subjects
Operational taxonomic unit, Rhodovulum, Flavobacteriales, Zoology, Bacterial Physiological Phenomena, Microbiology, Caulerpa lentillifera, 03 medical and health sciences, sea grape, Caulerpa, Microbiome, Rhodobacteraceae, 030304 developmental biology, Plant Diseases, 0303 health sciences, biology, Bacteria, Host Microbial Interactions, 030306 microbiology, Microbiota, Planctomycetes, Original Articles, green caviar, biology.organism_classification, QR1-502, Holobiont, aquaculture, Vietnam, seaweed, Original Article, 16S rRNA gene
Abstract

The bacterial communities of Caulerpa lentillifera were studied during an outbreak of an unknown disease in a sea grape farm from Vietnam. Clear differences between healthy and diseased cases were observed at the order, genus, and Operational Taxonomic Unit (OTU) level. A richer diversity was detected in the diseased thalli of C. lentillifera, as well as the dominance of the orders Flavobacteriales (phylum Bacteroidetes) and Phycisphaerales (Planctomycetes). Aquibacter, Winogradskyella, and other OTUs of the family Flavobacteriaceae were hypothesized as detrimental bacteria, this family comprises some well‐known seaweed pathogens. Phycisphaera together with other Planctomycetes and Woeseia were probably saprophytes of C. lentillifera. The Rhodobacteraceae and Rhodovulum dominated the bacterial community composition of healthy C. lentillifera. The likely beneficial role of Bradyrhizobium, Paracoccus, and Brevundimonas strains on nutrient cycling and phytohormone production was discussed. The bleaching of diseased C. lentillifera might not only be associated with pathogens but also with an oxidative response. This study offers pioneering insights on the co‐occurrence of C. lentillifera‐attached bacteria, potential detrimental or beneficial microbes, and a baseline for understanding the C. lentillifera holobiont. Further applied and basic research is urgently needed on C. lentillifera microbiome, shotgun metagenomic, metatranscriptomic, and metabolomic studies as well as bioactivity assays are recommended., The co‐occurrence of bacteria in sea grape (green caviar) Caulerpa lentillifera under two health state conditions was studied. The role of potentially detrimental and beneficial bacteria was discussed. A baseline for understanding the C. lentillifera holobiont was presented.

Published
2021

33. Bacterial community composition of the sea grape Caulerpa lentillifera: a comparison between healthy and diseased states

Author

Le Mai Huong, A. Kunzmann, A. Gaerdes, A. Fricke, Le Huu Cuong, Germán A. Kopprio, and Nguyen Dinh Luyen

Subjects
2. Zero hunger, 0303 health sciences, Operational taxonomic unit, Rhodovulum, biology, 030306 microbiology, Planctomycetes, biology.organism_classification, Caulerpa lentillifera, Holobiont, 03 medical and health sciences, Paracoccus, Thalassobius, Botany, Rhodobacteraceae, 030304 developmental biology
Abstract

SummaryThe bacterial communities of the sea grape Caulerpa lentillifera were studied during a disease outbreak in Vietnam. The Rhodobacteraceae and Rhodovulum dominated the composition of healthy C. lentillifera. Clear differences between healthy and diseased cases were observed at order, genus and Operational Taxonomic Unit (OTU) level. Bacterial diversity was lower in healthy C. lentillifera, probably because of antimicrobial compounds from the macroalgae and/or from Clostridium, Cutibacterium or Micrococcus bacteria. The likely beneficial role of Bradyrhizobium, Paracoccus and Brevundimonas strains on nutrient cycling and phytohormone production was discussed. The white coloration of diseased C. lentillifera may not only be associated with pathogens but also with an oxidative response. Aquibacter, Winogradskyella and other OTUs of the family Flavobacteriaceae were hypothesized as detrimental bacteria, this family comprises some well-known seaweed pathogens. Moreover, Thalassobius OTU 2935 and 1635 may represent detrimental Rhodobacteraceae. Phycisphaera together with other Planctomycetes and Woeseia were probably saprophytes of C. lentillifera. This study offers pioneering insights on the co-occurrence of C. lentillifera-attached bacteria, potential detrimental or beneficial microbes, and a baseline for understanding the C. lentillifera holobiont. Further metagenomic and biotechnological approaches are needed to confirm functions of some microbes on this macroalgae to enhance food security in the tropics.

Published
2021

34. Aspermicrones A-C, novel dibenzospiroketals from the seaweed-derived endophytic fungus Aspergillus micronesiensis

Author

Nguyen Dinh Luyen, Phan Van Kiem, Tran Thi Hong Ha, Nguyen Xuan Nhiem, Le Mai Huong, Duong Thi Hai Yen, Germán A. Kopprio, Le Huu Cuong, Astrid Gärdes, and Bui Huu Tai

Subjects
0301 basic medicine, Staphylococcus aureus, Magnetic Resonance Spectroscopy, Cell Survival, Stereochemistry, 030106 microbiology, Antineoplastic Agents, medicine.disease_cause, 01 natural sciences, Ciencias de la Tierra y relacionadas con el Medio Ambiente, Ciencias Biológicas, 03 medical and health sciences, Biología Celular, Microbiología, Algae, Drug Discovery, KAPPAPHYCUS, medicine, ASPERGILLUS, Animals, Humans, Molecule, Spiro Compounds, Furans, Pharmacology, Aspergillus, Molecular Structure, biology, 010405 organic chemistry, Chemistry, Oceanografía, Hidrología, Recursos Hídricos, Ciencias Químicas, Hep G2 Cells, Nuclear magnetic resonance spectroscopy, Endophytic fungus, Seaweed, Kappaphycus, biology.organism_classification, HR-ESI-MS, Anti-Bacterial Agents, 0104 chemical sciences, Hepg2 cells, Química Analítica, CIENCIAS NATURALES Y EXACTAS, ANTIBIOTIC
Abstract

Chemical investigation of the Kappaphycus alvarezii-derived endophytic fungus Aspergillus micronesiensis lead to the isolation of three novel dibenzospiroketals, aspermicrones A-C (1-3). Their chemical structures were determined by extensive analysis of HR-ESI-MS and NMR spectral data. The absolute configurations of them were determined by experimental and TD-DFT theoretical calculated circular dichroism spectra. Compound 2 exhibited selective cytotoxic effect toward HepG2 cell line (IC50 = 9.9 μM). Additionally, both of compounds 2 and 3 displayed anti-microbial activity against Staphylococcus aureus (MIC = 123.2 μM for each compound). Compound 1 was inactivity in both cytotoxic and antimicrobial assays. Fil: Luyen, Nguyen Dinh. Vietnam Academy of Science and Technology; Vietnam. Graduate University of Science and Technology; Vietnam Fil: Huong, Le Mai. Vietnam Academy of Science and Technology; Vietnam. Graduate University of Science and Technology; Vietnam Fil: Thi Hong Ha, Tran. Vietnam Academy of Science and Technology; Vietnam Fil: Cuong, Le Huu. Vietnam Academy of Science and Technology; Vietnam Fil: Thi Hai Yen, Duong. Institute of Marine Biochemistry; Vietnam Fil: Nhiem, Nguyen Xuan. Graduate University of Science and Technology; Vietnam. Institute of Marine Biochemistry; Vietnam Fil: Tai, Bui Huu. Graduate University of Science and Technology; Vietnam. Institute of Marine Biochemistry; Vietnam Fil: Gardes, Astrid. Leibniz Centre for Tropical Marine Research; Alemania Fil: Kopprio, Germán Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Leibniz Centre for Tropical Marine Research; Alemania Fil: Van Kiem, Phan. Graduate University of Science and Technology; Vietnam. Institute of Marine Biochemistry; Vietnam

Published
2019

35. ANTIMICROBIAL, CYTOTOXIC AND HEMOLYTIC ACTIVITIES OF MARINE ALGAE-ASSOCIATED FUNGAL ISOLATES IN VIETNAM

Author

Nguyen Dinh Tuan, Tran Thi Hong Ha, Le Thi Hong Nhung, Le Huu Cuong, Hoang Kim Chi, Le Mai Huong, and Tran Thi Nhu Hang

Subjects
Algae, Cytotoxic T cell, Biology, Antimicrobial, biology.organism_classification, Microbiology
Abstract

In the context of sources for natural products discovery are going scarcer, exploiting biotechnologically potential compounds from marine microbial symbionts is considered a relatively new trend. In our study a total of fifteen fungal strains were isolated from marine algal samples belonging to species Kappaphycus cottonii, K. striatus, Gracilaria eucheumatoides and Betaphycus gelatinus collected in Nha Trang in 2017. The in vitro biological activities, including antimicrobial, cytotoxic and hemolytic activities of ethyl acetate extracts of the fungal strains were determined. From fifteen fungal extracts, six displayed antimicrobial activity against at least one test strain. At 20 μg.ml-1, four fungal extracts were found to express cytotoxic activity on two human cancer cell lines hepatocellular carcinoma (Hep-G2) and breast adenocarcinoma (MCF-7), with G. eucheumatoides being the source of the highest number of producer strains. Hemolytic activity was observed in rabbit erythrocytes under almost all fungal extracts’ effect. No apparent relationship was observed between the biological activities of fungal isolates. The biological assessments uncovered several fungal candidates, such as Bge-1.1, Kco-2.1 and Geu-1.1 with relatively potent antimicrobial and cytotoxic activities while expressing less hemolytic effect at concentrations from 20 μg.ml-1 to 200 μg.ml-1. The results evidenced the potential of exploiting natural products from associated marine microorganisms, especially those for the purpose of pharmaceutical applications.

Published
2019

36. Carrageenophyte-attached and planktonic bacterial communities in two distinct bays of Vietnam: Eutrophication indicators and insights on ice-ice disease

Author

Le Mai Huong, Tran Mai Duc, Germán A. Kopprio, Nguyen Dinh Luyen, Astrid Gärdes, Tran Thi Hong Ha, and Le Huu Cuong

Subjects
0106 biological sciences, Ruegeria, EUCHEMA, General Decision Sciences, 010501 environmental sciences, 010603 evolutionary biology, 01 natural sciences, VIBRIO, purl.org/becyt/ford/1 [https], purl.org/becyt/ford/1.5 [https], Euchema, Pseudoalteromonas, POLLUTION, KAPPAPHYCUS, Dominance (ecology), 14. Life underwater, Alteromonas, purl.org/becyt/ford/1.6 [https], 16S RRNA DIVERSITY, Ecology, Evolution, Behavior and Systematics, QH540-549.5, 0105 earth and related environmental sciences, Vibrio, biology, Ecology, Kappaphycus, Bacterioplankton, 15. Life on land, Plankton, biology.organism_classification, Pollution, 6. Clean water, 13. Climate action, 16S rRNA diversity, Bay
Abstract

The composition of the bacterial community of carrageenophyte-attached and planktonic bacteria was studied in two bays of Vietnam with contrasting anthropogenic inputs to assess their role as ecological indicators. Clear differences (~73% dissimilarity) between carrageenophyte-attached bacteria and bacterioplankton were detected in terms of genus composition: mainly Agaribacter, Ruegeria, Alteromonas, the Pir4 lineage and Vibrio for the carrageenophytes and Candidatus Actinomarina, HIMB 11, NS groups and SAR clades for the bacterioplankton. The copiotrophic nature, potential for complex-polymer degradation, and ability to form and defend biofilms were common features inferred for the carrageenophyte-attached microbiome. Significant differences between the bays were detected in the concentration of most inorganic nutrients. More eutrophic conditions and presumptive wastewater pollution in Cam Ranh (CR) bay were primarily indicated by the dominance of Rubripirellula, Leptobacterium, Hypnocyclicus and Porphyrobacter and their correlations with phosphate. In terms of bacterioplankton, the influence of intensive aquaculture in CR bay was suggested by the dominance of the NS5 and NS4 marine groups, the SUP05 cluster, Flavobacteriaceae unclassified and SAR 11 clade III as well as their strong correlations with ammonium and phosphate. The link between silicate and other inorganic nutrients suggests freshwater input in CR bay. Arenicellaceae unclassified and Formosa were also potential indicators of eutrophication. Operational taxonomic units (OTUs) of Marinagarivorans, Cobetia, Vibrio, Alteromonas and Pseudoalteromonas were typical of the carrageenophytes showing ice-ice disease symptoms. Vibrio and Alteromonas were also common among healthy macroalgae, and differences at the OTU level suggested potential succession of species from the healthy to the diseased state. The probable beneficial roles of some bacteria, such as Ruegeria, Cutibacterium and unidentified members of the family Rhizobiaceae, were discussed. This study provides pioneering insights into the bacterial community composition of carrageenophytes and highlights their ecological value as strong indicators of the sources of organic matter, anthropogenic impacts and health status of marine systems. Fil: Kopprio, Germán Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Leibniz - Institute of Freshwater Ecology and Inland Fisheries; Alemania. Vietnam Academy of Science and Technology. Institute of Natural Product Chemistry; Vietnam Fil: Cuong, Le Huu. Vietnam Academy of Science and Technology. Graduate University of Science and Technology; Vietnam. Vietnam Academy of Science and Technology. Institute of Natural Product Chemistry; Vietnam Fil: Luyen, Nguyen Dinh. Vietnam Academy of Science and Technology. Graduate University of Science and Technology; Vietnam. Vietnam Academy of Science and Technology. Institute of Natural Product Chemistry; Vietnam Fil: Duc, Tran Mai. Vietnam Academy of Science and Technology. Nhatrang Institute of Technology Research and Application; Vietnam Fil: Ha, Tran Hong. Vietnam Academy of Science and Technology. Graduate University of Science and Technology; Vietnam Fil: Huong, Le Mai. Vietnam Academy of Science and Technology. Institute of Natural Product Chemistry; Vietnam. Vietnam Academy of Science and Technology. Graduate University of Science and Technology; Vietnam Fil: Gärdes, Astrid. Leibniz - Institute of Freshwater Ecology and Inland Fisheries; Alemania. University of Applied Sciences; Alemania. Alfred-Wegener-Institut. Helmholtz-Zentrum für Polar und Meeresforschung; Alemania

Published
2021

37. Logistics Human Resources in Vietnam as the Key Issue

Author

Nguyen Van Quy, Le Huu Cuong, and Nguyen Danh Chan

Abstract

Vietnam is one of the four Southeast Asian countries with great potential in developing both infrastructure and logistics systems. Along with the system of seaports and interlaced rivers is a great advantage to develop the logistics industry. However, the reality shows that the opposite is that human resources are the most difficult problem of the logistics industry today, due to hot development, the human resources of this industry are both insufficient and weak. Therefore, the survey of the current situation of human resources of the Logistics industry to propose solutions to develop human resources to improve the competitiveness of Logistics Vietnam in the global service chain is an endless issue. It is urgently needed to have great investment from the Government of Vietnam as well as domestic and foreign organizations.

Published
2019
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38. Developing Traffic Together with Environmental Protection

Author

Nguyen Van Quy, Dong Thi Minh Hao, Nguyen Thi Hoa, and Le Huu Cuong

Abstract

Along with the development of Vietnam's economy, transportation plays an extremely important role in the development process. However, in parallel with this development, transportation development also causes many obstacles in protecting the environment. Although the organization of transport and management of transport means has made great progress, it has not yet met the requirements of reducing congestion in big cities, which are increasingly serious, affecting economic growth and increasing. environmental pollution, reducing the quality of life of people. In line with the current trend of environmental protection, the fact that countries around the world start developing green transportation systems is an indispensable part, Vietnam is not outside this.

Published
2019
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41. How Climate Change Affects Vietnam and Methods to Prevent Climate Change

Author

Le Huu Cuong, Nguyen Van Quy, and Thi Minh Hao Dong

Abstract

Climate change is a challenge for all countries in the world and Vietnam is one of them. Vietnam has a long coastline and it is for this reason that it has become one of the countries most affected by climate change. Previously, climate change occurred in a long time due to the impact of nature. However, in recent years, climate change has become more and more complex under the influence of humans. Climate change has been adversely affecting life, economy, politics, culture and society, so the study and application of solutions to protect the environment and prevent climate change is a very important. The proposed solutions have partly solved the problem of climate change and environmental pollution but this is a global problem, so it is necessary to join hands of all humanity to solve this problem. The education of climate change in Vietnam needs to be taken seriously from kindergartens and primary schools in order to protect the environment of the country and the world in order to solve this problem. the most effective.

Published
2019
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42. The Current Environmental Situation and Green Solutions for Vietnam's East Sea

Author

Dong, Thi Minh Hao, Le, Huu Cuong, Truong, Thanh Hai, Dong, Thi Minh Hao, Le, Huu Cuong, and Truong, Thanh Hai

Abstract

The South China Sea, including the Vietnam Sea, is witnessing significant changes under the impact of both nature and man. These are the impacts of climate change and ocean change with "extreme" signs such as increasing storms, coastal floods, sea level rise, sea acidification, pollution and environmental incidents, ... occur thicker, more intense and irregular. Especially serious degradation of the environment and biodiversity of the sea, increasing environmental incidents, including oil spills, ... due to human impact. Especially the large-scale destruction of coral reefs, seagrass beds in island clusters off the South China Sea has been happening at a worrying rate. The destructive fishing activities of humans in the South China Sea have caused ecosystem degradation and the extinction of some species, such as sea turtles, some sharks and another species. Other fish, especially the giant mussel, the consequence is a decrease in the natural capital of the sea, leading too prolonged "ecological disturbances". The reserves of seafood in the Spratly region (of Vietnam) and the West Sea in the East Sea have decreased by about 19% compared to before 2017. Therefore, the improvement of marine environment quality, including biodiversity conservation and major marine ecosystems are to preserve marine natural assets, contributing to the implementation of Vietnam's green growth strategy and action plan. This is the path that Vietnam has chosen to both grow marine economy, adapt to climate change, and protect the environment both in the short and long term, towards sustainable development.

Published
2019

43. Potential Application of Biofuel Fuel on the Marine Diesel Engines in Vietnam

Author

Vu, Minh Thai, Le, Huu Cuong, Vu, Minh Thai, and Le, Huu Cuong

Abstract

Energy in the transportation sector has become a hot issue all over the world because it can affect the energy security of nations. Finding a new type of energy to replace fossil energy is a top concern of many countries, including biofuels. Over the past two decades, there have been many studies on the use of biodiesel and its mix for diesel engines, the results are very positive. In Vietnam, there have also been studies on the use of biodiesel and its mixes on road transport vehicles. However, in the field of waterway transport, there has not been any specific research. Through a comprehensive synthesis of the application situation and research directions in the world, as well as the ability to produce biodiesel in Vietnam, the article wishes to create a premise to develop more research to find develop new technology solutions to apply clean fuels, especially biofuels on the domestic fleet, in line with the development trend of the world on the use of biodiesel fuel.

Published
2019

44. The Characteristics of Carbonyl Compounds Emissions from Small Marine Diesel Engines Using Biodiesel Based Palm Oil

Author

Nguyen, Van Quy, Le, Huu Cuong, Nguyen, Van Quy, and Le, Huu Cuong

Abstract

The study was conducted to measure and evaluate particulate emissions and carbonyl compounds from KAMA - KDE3500T generator at medium load mode (1.5 kW load). Using commercial diesel fuel 0.05 S and biodiesel palm oil with different mixing ratios are: 0%, 10%, 20%, 30%, 50%, 75% and 100% for B0, B10, B20, B30, B50, B75 and B100. Experimental results showed that: dust emission concentration decreased from B0 to B20 and increased from B30 to B100 namely 348.65 mg / m3, 297.27 mg / m3, 168.59 mg / m3, 169.74 mg / m3, 259.98 mg / m3, 330.30 mg / m3, 522.98 mg / m3 respectively for B0, B10, B20, B30, B50, B75, B100.  Carbonyl emission concentrations increased from B0 to B30 and abruptly decreased at B50 and gradually increased at B75 and B100 specific figures as follows: 67.99 mg / m3, 87.35 mg / m3, 99.10 mg / m3, 100.96 mg / m3, 65.79 mg / m3, 102.32 mg / m3, 102.38 mg / m3 respectively for B0, B10, B20, B30, B50, B75 and B100. High concentrations of carbonyl compounds are formaldehyde, acetaldehyde and acetone.

Published
2019

45. The Study Influences the Jatropha-Diesel Mixing Ratio to the Formation of Soot Emissions in Diesel Exhaust Gases

Author

Nguyen, Van Quy, Le, Huu Cuong, Nguyen, Van Quy, and Le, Huu Cuong

Abstract

To cope with the depletion of fossil fuels and the threat of exhaust pollution from internal combustion engines, research finds alternative fuels. Step by step to completely replace fossil fuels that will be exhausted in the future and environmentally friendly due to internal combustion engines is an urgent and important issue. Diversify fuel sources used for internal combustion engines and environmentally friendly when using Jatropha - Diesel fuel mixture. The paper focuses on studying the ability to use biodiesel derived from Jatropha seeds with the volume ratios of 5%, 10% and 15% on experimental engines. Thereby, it will analyze and evaluate the technical features and pollution levels of engines compared to pure fuels. Experimental study assessing the effect of Jatropha - Diesel mixing ratio on the emission formation compared with emissions in Vikyno EV2600 engines.

Published
2019

46. Biological characterization of fungal endophytes isolated from agarwood tree Aquilaria crassna Pierre ex Lecomte

Author

Tran Thi Hong Ha, Hoang Kim Chi, Le Mai Huong, Tran Thi Nhu Hang, Nguyen Dinh Luyen, and Le Huu Cuong

Subjects
Tree (data structure), biology, Botany, engineering, Aquilaria crassna, Agarwood, engineering.material, biology.organism_classification
Abstract

In recent years, a considerable number of studies on the role of microbes in agarwood production have been carried out in plants of the species Aquilaria. Based on the fact that there is a relationship between the microorganisms residing inside the plant and the agarwood formation, we isolated and characterized endophytic fungi associated with A. crassna samples collected from Southern Vietnam. Morphological identification and DNA barcoding analysis of the fungal endophytic isolates indicated that they were classified at least into three groups of diverse genera: Geotrichum, Fusarium and Colletotrichum belonging to families Dipodascaceae, Nectriaceae and Glomerellaceae, respectively. Noteworthy, Geotrichum candium strain SHTr1 isolated from a dark colored woody sample of agarwood was able to produce a fruity odor and exhibited a slight antimicrobial activity against the test bacterium Staphylococcus aureus. Another fungal isolate, Fusarium verticillioides SHTr3’s, showed a moderate antimicrobial activity against a test Gram positive bacteria Bacillus subtillis and S. aureus with MIC values at 50 μg.mL-1. At 200 μg.mL-1, the ethyl acetate extracts of fungal isolates F. verticillioides SHTr3 and Colletotrichum truncatum SHTrHc7 were found to have comparable scavenging abilities on DPPH-free radicals with 53.87 and 71.82%, respectively. The present results contribute to a depiction of a diverse fungal endophytic community in Vietnamese agarwood plant A. crassna and provide important information for further understanding of the role of endophytic fungi in agarwood formation and therapeutic applications of host plants in general.

Published
2016

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