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  • 11
    In: Diversity, MDPI AG, Vol. 15, No. 9 ( 2023-08-24), p. 958-
    Abstract: Overexploitation has driven catastrophic declines in most turtle species in Asia. Many turtles are seized annually by law enforcement officers; unfortunately, seized turtles often lack associated information on their provenance. There is also taxonomic confusion regarding the clear delineation of turtle species and subspecies in Asia. This lack of provenance data and taxonomic uncertainty is problematic as it may preclude release, make appropriate release sites hard to select, or result in genetic pollution when animals are released. In this study, we amassed and analyzed the largest number of genetic samples of the critically endangered big-headed turtle (Platysternon megacephalum) to date. Our phylogenetic and network results based on nearly 500 sequences of a mitochondrial ND4 fragment corroborate the earlier hypothesis that only two of the three currently recognized subspecies have strong molecular support and that there is greater genetic structuring within one subspecies than has been previously reported. The vast majority of P. megacephalum confiscated from the trade in Vietnam belong to Subclade 3 of P. m. peguense, and this subclade is the most broadly distributed taxon of the big-headed turtle in Vietnam based on samples with known localities. Nonetheless, for the other two subclades, all their samples originate from the trade and could not be assigned to any geographic provenance because of the lack of wild-caught samples. In addition, our results reveal two trade centers of the species, Quang Ninh Province on the border between China and Vietnam and Kon Tum Province in the Central Highlands. However, smaller animal seizures occur across the range of the species in Vietnam. While the data presented here have facilitated the selection of appropriate release sites for confiscated P. megacephalum, the significant costs of genetic screening and the shortage of samples from wild animals with good localities hinder the rewilding efforts, especially for conservation practitioners working in countries where conservation activities are not well funded and research on poorly studied species is still limited. Nevertheless, we urge that wildlife translocations include robust pre-translocation genetic screening to ensure that all individual animals are reintroduced at appropriate sites.
    Type of Medium: Online Resource
    ISSN: 1424-2818
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2518137-3
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  • 12
    In: Materials, MDPI AG, Vol. 13, No. 14 ( 2020-07-11), p. 3099-
    Abstract: Alpha-calcium sulfate hemihydrate (α-HH) has been used effectively in grafting through its desired features to support bone regeneration. In recent years, many synthetic methods have been proposed. Among them, the autoclave method for manufacturing α-HH is best suited for cost-savings due to its simple operation and limited use of additives. Despite these advantages, the synthesis of surgical grade products without the use of any additives has not yet been clearly discussed. In this study, surgical grade α-HH was successfully produced from calcium sulfate dihydrate (DH) using the autoclave method at an elevated temperature and pressure. The synthesized powder had a high purity of about 98.62% α-HH with a prismatic morphology (20.96 ± 8.83 µm in length and 1.30 ± 0.71 µm in diameter). The screening tests, in simulated body fluid (SBF) solution, for the product properties showed no bioactivity, and fast degradation accompanied by a slight decrease in pH. The lactate dehydrogenase (LDH) assay showed good biocompatibility of the material, however, its potential for cytotoxicity was also observed in NIH 3T3 cells. Briefly, despite some unfavorable properties, the autoclave-synthesized α-HH is a promising bone graft substitute that can be applied in orthopedic and maxillofacial surgeries.
    Type of Medium: Online Resource
    ISSN: 1996-1944
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2487261-1
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  • 13
    In: Applied Sciences, MDPI AG, Vol. 9, No. 24 ( 2019-12-12), p. 5458-
    Abstract: The principal purpose of this work is to develop three hybrid machine learning (ML) algorithms, namely ANFIS-RCSA, ANFIS-CA, and ANFIS-SFLA which are a combination of adaptive neuro-fuzzy inference system (ANFIS) with metaheuristic optimization techniques such as real-coded simulated annealing (RCSA), cultural algorithm (CA) and shuffled frog leaping algorithm (SFLA), respectively, to predict the critical buckling load of I-shaped cellular steel beams with circular openings. For this purpose, the existing database of buckling tests on I-shaped steel beams were extracted from the available literature and used to generate the datasets for modeling. Eight inputs, considered as independent variables, including the beam length, beam end-opening distance, opening diameter, inter-opening distance, section height, web thickness, flange width, and flange thickness, as well as one output of the critical buckling load of cellular steel beams considered as a dependent variable, were used in the datasets. Three quality assessment criteria, namely correlation coefficient (R), root mean squared error (RMSE) and mean absolute error (MAE) were employed for assessment of three developed hybrid ML models. The obtained results indicate that all three hybrid ML models have a strong ability to predict the buckling load of steel beams with circular openings, but ANFIS-SFLA (R = 0.960, RMSE = 0.040 and MAE = 0.017) exhibits the best effectiveness as compared with other hybrid models. In addition, sensitivity analysis was investigated and compared with linear statistical correlation between inputs and output to validate the importance of input variables in the models. The sensitivity results show that the most influenced variable affecting beam buckling capacity is the beam length, following by the flange width, the flange thickness, and the web thickness, respectively. This study shows that the hybrid ML techniques could help in establishing a robust numerical tool for beam buckling analysis. The proposed methodology is also promising to predict other types of failure, as well as other types of perforated beams.
    Type of Medium: Online Resource
    ISSN: 2076-3417
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2704225-X
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  • 14
    In: Processes, MDPI AG, Vol. 10, No. 7 ( 2022-06-27), p. 1268-
    Abstract: (1) Background: Hedera nepalensis (Araliaceae) is a recognized medicinal plant founded in Asia that has been reported to work in antioxidant, antifungal, antimicrobial, and antitumor capacities. (2) Methods: The subcritical fluid extraction of saponin from Hedera nepalensis leaves and the optimum of the extraction process based on yield of saponin contents (by calculating the hederacoside C contents in dried Hedera nepalensis leaves) are examined by response surface methodology (RSM). Furthermore, the antimicrobial activity of the extract is tested for potential drug applications in the future. (3) Results: Based upon RSM data, the following parameters are optimal: extraction time of 3 min, extraction temperature of 150 °C, and a sample/solvent ratio of 1:55 g/mL. Under such circumstances, the achieved yield of saponin is 1.879%. Moreover, the extracts inhibit the growth of some bacterial strains (Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenza) at a moderate to strong level with inhibition zone diameter values ranging from 12.63 to 19.50 mm. (4) Conclusions: The development of such a model provides a robust experimental process for optimizing the extraction factors of saponin contents from Hedera nepalensis extract using subcritical fluid extraction and RSM. Moreover, the current work reveals that saponin extracts of Hedera nepalensis leaves exhibit a potential antimicrobial activity, which can be used as scientific evidence for further study.
    Type of Medium: Online Resource
    ISSN: 2227-9717
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2720994-5
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  • 15
    In: Water, MDPI AG, Vol. 13, No. 10 ( 2021-05-11), p. 1330-
    Abstract: Temporal and spatial water quality data are essential to evaluate human health risks. Understanding the interlinking variations between water quality and socio-economic development is the key for integrated pollution management. In this study, we applied several multivariate approaches, including trend analysis, cluster analysis, and principal component analysis, to a 15-year dataset of water quality monitoring (1999 to 2013) in the Thi Vai estuary, Southern Vietnam. We discovered a rapid improvement for most of the considered water quality parameters (e.g., DO, NH4, and BOD) by step trend analysis, after the pollution abatement in 2008. Nevertheless, the nitrate concentration increased significantly at the upper and middle parts and decreased at the lower part of the estuary. Principal component (PC) analysis indicates that nowadays the water quality of the Thi Vai is influenced by point and diffuse pollution. The first PC represents soil erosion and stormwater loads in the catchment (TSS, PO4, and Fetotal); the second PC (DO, NO2, and NO3) determines the influence of DO on nitrification and denitrification; and the third PC (pH and NH4) determines point source pollution and dilution by seawater. Therefore, this study demonstrated the need for stricter pollution abatement strategies to restore and to manage the water quality of the Thi Vai Estuary.
    Type of Medium: Online Resource
    ISSN: 2073-4441
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2521238-2
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  • 16
    In: Journal of Fungi, MDPI AG, Vol. 9, No. 10 ( 2023-09-29), p. 981-
    Abstract: Stem-end rot disease has been causing damage to the production of pomelos in Vietnam. The cur-rent study aimed to (i) isolate fungal pathogens causing pomelo stem-end rot disease (PSERD) and (ii) discover Trichoderma spp. that had an antagonistic ability against pathogens under in vitro conditions. Fungi causing PSERD were isolated from pomelo fruits with symptoms of stem-end rot disease and collected from pomelo farms in Ben Tre province, Vietnam. Moreover, 50 fungal strains of Trichoderma spp. also originated from soils of these pomelo farms in Ben Tre province and were dual-tested with the fungal pathogen on the PDA medium. The results demonstrated that 11 pathogenic fungi causing PSERD were isolated from the fruit and showed mycelial growth of roughly 5.33–8.77 cm diameter at 72 h after inoculation. The two fungi that exhibited the fast-est growth, namely, S-P06 and S-P07, were selected. ITS sequencing of the S-P06 and S-P07 fungi resulted in Lasiodiplodia theobromae. All the 50 Trichoderma spp. strains were allowed to antago-nize against the S-P06 and S-P07 strains under in vitro conditions. The greatest antagonistic effi-ciency was found in Trichoderma spp. T-SP19 at 85.4–86.2% and T-SP32 at 84.7–85.4%. The two antagonists were identified as Trichoderma asperellum T-SP19 and T-SP32. The selected strains of Trichoderma asperellum were potent as a biological control for fruit plants.
    Type of Medium: Online Resource
    ISSN: 2309-608X
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2784229-0
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  • 17
    In: AgriEngineering, MDPI AG, Vol. 4, No. 4 ( 2022-11-14), p. 1116-1138
    Abstract: Honey is a natural product made by honeybees, its composition depends on factors such as climate, soil and plant source. In this study, the nutritional parameters, phenolic composition, antioxidant activity and antibacterial ability of 30 different types of honey of different botanical and geographical origins in Vietnam were investigated. The study focused on the characterization and evaluation of the influence of plant origin and geographical location on physical–chemical properties and biological activities (antioxidant and antibacterial). The obtained results show that all honey samples meet quality standards according to international standards and Vietnamese standards, except for some exceptions recorded in moisture, 5-hydroxymethylfurfural (HMF) value and ash. These samples were explored for the detection of 13 polyphenols by using high-performance liquid chromatography (HPLC). The classification of honey samples collected from different regions and botanical sources was performed by principal component analysis (PCA), and it was observed that certain phenolic compounds contributed to the identification of honey samples. In addition, the correlation between physicochemical properties, chemical composition and biological activity of most honeys was also first clarified in this study. Overall, our data provide an overview data set and essential results in creating a database on the world honey trait map.
    Type of Medium: Online Resource
    ISSN: 2624-7402
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2946408-0
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  • 18
    In: Symmetry, MDPI AG, Vol. 12, No. 2 ( 2020-02-21), p. 307-
    Abstract: Face recognition (FR) has received considerable attention in the field of security, especially in the use of closed-circuit television (CCTV) cameras in security monitoring. Although significant advances in the field of computer vision are made, advanced face recognition systems provide satisfactory performance only in controlled conditions. They deteriorate significantly in the face of real-world scenarios such as lighting conditions, motion blur, camera resolution, etc. This article shows how we design, implement, and conduct the empirical comparisons of machine learning open libraries in building attendance taking (AT) support systems using indoor security cameras called ATSS. Our trial system was deployed to record the appearances of 120 students in five classes who study on the third floor of FPT Polytechnic College building. Our design allows for flexible system scaling, and it is not only usable for a school but a generic attendance system with CCTV. The measurement results show that the accuracy is suitable for many different environments.
    Type of Medium: Online Resource
    ISSN: 2073-8994
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2518382-5
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  • 19
    In: Nanomaterials, MDPI AG, Vol. 10, No. 2 ( 2020-02-17), p. 337-
    Abstract: Titanium dioxide (TiO2) has attracted increasing attention as a candidate for the photocatalytic reduction of carbon dioxide (CO2) to convert anthropogenic CO2 gas into fuels combined with storage of intermittent and renewable solar energy in forms of chemical bonds for closing the carbon cycle. However, pristine TiO2 possesses a large band gap (3.2 eV), fast recombination of electrons and holes, and low selectivity for the photoreduction of CO2. Recently, considerable progress has been made in the improvement of the performance of TiO2 photocatalysts for CO2 reduction. In this review, we first discuss the fundamentals of and challenges in CO2 photoreduction on TiO2-based catalysts. Next, the recently emerging progress and advances in TiO2 nanostructured and hybrid materials for overcoming the mentioned obstacles to achieve high light-harvesting capability, improved adsorption and activation of CO2, excellent photocatalytic activity, the ability to impede the recombination of electrons-holes pairs, and efficient suppression of hydrogen evolution are discussed. In addition, approaches and strategies for improvements in TiO2-based photocatalysts and their working mechanisms are thoroughly summarized and analyzed. Lastly, the current challenges and prospects of CO2 photocatalytic reactions on TiO2-based catalysts are also presented.
    Type of Medium: Online Resource
    ISSN: 2079-4991
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2662255-5
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  • 20
    In: Forests, MDPI AG, Vol. 12, No. 11 ( 2021-11-22), p. 1610-
    Abstract: Pine tussock moth (Dasychira axutha Collenette (Lymantriidae)) and masson pine caterpillar (Dendrolimus punctatus Walker (Lasiocampidae)) cause serious damage to Pinus massoniana and P. merkusii plantations in Vietnam. An integrated pest management (IPM) program is required to control these pests. Therefore, this study was undertaken to identify damage thresholds and to evaluate control options for implementing IPM in the Northeast and North Central regions of Vietnam. Three damage thresholds were considered: 〈 25%, 25%–50% and 〉 50% loss of leaf area. Control options were manual collection of eggs and pupae and the use of light traps and biological agents. An initial IPM model was developed for each pest and these gave control efficacies of 82.4% (Da. axutha on P. massoniana) and 77.8% (De. punctatus on P. merkusii). Six extended IPM models were undertaken by forest companies giving pest control efficacies of 79.2%–85.9%. The collection of pine resin provides an important source of income to local communities and the resin yield in the IPM models increased by 20.9%–22.7% compared to untreated control plots. The IPM protocols would help in developing policies that promote a more sustainable management of forest pests in Vietnam, thus reducing dependence on the use of insecticides of environmental and public health concerns.
    Type of Medium: Online Resource
    ISSN: 1999-4907
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2527081-3
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