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  • 1
    In: Tạp Chí Khoa Học Trường Đại Học Quốc Tế Hồng Bàng, Hong Bang International University, ( 2024-01-24), p. 115-122
    Abstract: Đặt vấn đề: Nhóm hợp chất flavonoid trong dược liệu cỏ mực (Eclipta prostrata L.) có hoạt tính kháng khuẩn, kháng nấm, cầm máu, bảo vệ gan,…. Có nhiều phương pháp định lượng nhóm hợp chất flavonoid toàn phần ở Việt Nam và trên thế giới, riêng dược liệu cỏ mực và các dạng bào chế chiết suất từ dược liệu cỏ mực được định lượng flavonoid toàn phần (theo Wedelolactone) bằng phương pháp tạo màu với hỗn hợp thuốc thử nhôm chloride, natri nitrite và natri hydroxide đo quang phổ UV - Vis ở bước sóng 345 nm chưa được thực hiện. Vì vậy việc xây dựng và thẩm định quy trình định lượng flavonoid toàn phần (theo Wedelolactone) trong cao đặc cỏ mực là cần thiết. Mục tiêu: Xây dựng và thẩm định quy trình định lượng flavonoid toàn phần (theo Wedelolactone) trong cao đặc cỏ mực. Đối tượng và phương pháp nghiên cứu: Cao đặc cỏ mực, tiến hành xây dựng và thẩm định quy trình định lượng flavonoid toàn phần (theo chất chuẩn Wedelolactone) trong cao đặc cỏ mực. Kết quả: Đã xây dựng và thẩm định quy trình định lượng đạt yêu cầu theo hướng dẫn của ICH trên các tiêu chí: tính tương thích hệ thống, tính đặc hiệu, tính tuyến tính, độ chính xác và độ đúng. Kết luận: Phương pháp định lượng có ưu điểm nhanh và đơn giản nên có thể ứng dụng vào công tác kiểm tra nhanh nguồn nguyên liệu đầu vào ứng dụng trong sản xuất.
    Type of Medium: Online Resource
    ISSN: 2615-9686
    URL: Issue
    Language: Unknown
    Publisher: Hong Bang International University
    Publication Date: 2024
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  • 2
    In: Scientific Reports, Springer Science and Business Media LLC, Vol. 13, No. 1 ( 2023-06-29)
    Abstract: The sliding mode control is well-known as a useful control technique that can be applied in several real-world applications. However, a straightforward and efficient process of selecting the sliding mode control gains remains a challenging but interesting topic. This paper investigates a novel gain tuning method for the sliding mode control of second-order mechanical systems. Firstly, we obtain relations between the gains and the natural and damping ratio of the closed-loop system. Secondly, the time constant of the system’s actuators and the system response performance criteria, including settling time and delay time, are taken into consideration to determine appropriate ranges of the gains. These gain ranges allow control designers to select the controller gains in a time-saving manner and ensure that the desired system performance is met and the actuators work properly. Finally, the proposed method is applied to the gain tuning process of a sliding mode altitude controller for an actual quadcopter unmanned aerial vehicle. Simulation and experimental results demonstrate the applicability and effectiveness of this method.
    Type of Medium: Online Resource
    ISSN: 2045-2322
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 2615211-3
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  • 3
    Online Resource
    Online Resource
    Can Tho University ; 2023
    In:  CTU Journal of Innovation and Sustainable Development Vol. 15, No. 2 ( 2023-07-14), p. 1-10
    In: CTU Journal of Innovation and Sustainable Development, Can Tho University, Vol. 15, No. 2 ( 2023-07-14), p. 1-10
    Abstract: In this study, Fe3O4/GO/PVP (FGP) was successfully synthesized and efficiently applied for absorbing methylene blue. First, GO was synthesized by Hummer’s method from waste home-batteries. The chemical co-precipitation method was used to fabricate Fe3O4/GO from a mixture solution of GO, Fe3+, Fe2+. Polyvinylpyrrolidone PVP was selected to functionalize Fe3O4/GO and form Fe3O4/GO/PVP for improving dispersibility purpose in aqueous solution. The obtained Fe3O4/GO/PVP was characterized by XRD, FT-IR, BET, FE-SEM, UV-Vis techniques. Moreover, the effecting factors as pH, time adsorption, initial concentration of methylene blue were conducted. Adsorption isotherm models were also identified. The results showed that specific surface area of FGP-3 was 70.0 m2.g-1, the Freundlich isotherm model was suitable and the Dubinin - Radushkevich isotherm model showed that the process was physical adsorption. The maximum capacity (qmax) was 30.4 mg.g-1. These findings prove Fe3O4/GO/PVP as an inexpensive and efficient adsorbent for removal of cationic dyes.
    Type of Medium: Online Resource
    ISSN: 2815-6412 , 2588-1418
    Language: Unknown
    Publisher: Can Tho University
    Publication Date: 2023
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  • 4
    Online Resource
    Online Resource
    Frontiers Media SA ; 2024
    In:  Frontiers in Chemistry Vol. 12 ( 2024-4-16)
    In: Frontiers in Chemistry, Frontiers Media SA, Vol. 12 ( 2024-4-16)
    Abstract: Introduction: 3D pharmacophore models describe the ligand’s chemical interactions in their bioactive conformation. They offer a simple but sophisticated approach to decipher the chemically encoded ligand information, making them a valuable tool in drug design. Methods: Our research summarized the key studies for applying 3D pharmacophore models in virtual screening for 6,944 compounds of APJ receptor agonists. Recent advances in clustering algorithms and ensemble methods have enabled classical pharmacophore modeling to evolve into more flexible and knowledge-driven techniques. Butina clustering categorizes molecules based on their structural similarity (indicated by the Tanimoto coefficient) to create a structurally diverse training dataset. The learning method combines various individual pharmacophore models into a set of pharmacophore models for pharmacophore space optimization in virtual screening. Results: This approach was evaluated on Apelin datasets and afforded good screening performance, as proven by Receiver Operating Characteristic (AUC score of 0.994 ± 0.007), enrichment factor of (EF1% of 50.07 ± 0.211), Güner-Henry score of 0.956 ± 0.015, and F-measure of 0.911 ± 0.031. Discussion: Although one of the high-scoring models achieved statistically superior results in each dataset (AUC of 0.82; an EF1% of 19.466; GH of 0.131 and F1-score of 0.071), the ensemble learning method including voting and stacking method balanced the shortcomings of each model and passed with close performance measures.
    Type of Medium: Online Resource
    ISSN: 2296-2646
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2024
    detail.hit.zdb_id: 2711776-5
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  • 5
    In: Diabetes & Metabolic Syndrome: Clinical Research & Reviews, Elsevier BV, Vol. 13, No. 2 ( 2019-03), p. 1667-1673
    Type of Medium: Online Resource
    ISSN: 1871-4021
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2019
    detail.hit.zdb_id: 2273766-2
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  • 6
    In: IOP Conference Series: Earth and Environmental Science, IOP Publishing, Vol. 947, No. 1 ( 2021-12-01), p. 012008-
    Abstract: The aim of this paper is to propose a model to simulate the behaviour of water flows in shell and tube heat exchanger. Particularly, the continuity equation, the general heat transfer equations and the energy equation in COMSOL Multiphysics software were implemented in the numerical modelling. Besides, the experiment was also conducted to validate the proposed COMSOL model. The water temperature at locations close to the inlet and outlet of the shell side was respectively predicted at 31.5°C and 34.6°C in the simulation, and it was respectively measured at 31.5°C and 35°C in the experiment. These findings showed that the simulation results had a good agreement with the experiment. Next, this model was extended to simulate the overall heat coefficient and the pressure drops of the water flows in such heat exchanger. The overall heat coefficient was at 736.62 W/m 2 K. The pressure drops at the inlet/outlet areas of the shell and tubes were at 849.93 Pa and 6255.50 Pa, respectively. Conclusive evidence showed that the proposed model is a reliable method for studying the heat transfer behaviour of the shell and heat exchanger.
    Type of Medium: Online Resource
    ISSN: 1755-1307 , 1755-1315
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2021
    detail.hit.zdb_id: 2434538-6
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  • 7
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 52, No. 8 ( 2021-08), p. 2502-2509
    Abstract: The AFFINITY trial (Assessment of Fluoxetine in Stroke Recovery) reported that oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and seizures. After trial medication was ceased at 6 months, survivors were followed to 12 months post-randomization. This preplanned secondary analysis aimed to determine any sustained or delayed effects of fluoxetine at 12 months post-randomization. Methods: AFFINITY was a randomized, parallel-group, double-blind, placebo-controlled trial in adults (n=1280) with a clinical diagnosis of stroke in the previous 2 to 15 days and persisting neurological deficit who were recruited at 43 hospital stroke units in Australia (n=29), New Zealand (4), and Vietnam (10) between 2013 and 2019. Participants were randomized to oral fluoxetine 20 mg once daily (n=642) or matching placebo (n=638) for 6 months and followed until 12 months after randomization. The primary outcome was function, measured by the modified Rankin Scale, at 6 months. Secondary outcomes for these analyses included measures of the modified Rankin Scale, mood, cognition, overall health status, fatigue, health-related quality of life, and safety at 12 months. Results: Adherence to trial medication was for a mean 167 (SD 48) days and similar between randomized groups. At 12 months, the distribution of modified Rankin Scale categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio, 0.93 [95% CI, 0.76–1.14]; P =0.46). Compared with placebo, patients allocated fluoxetine had fewer recurrent ischemic strokes (14 [2.18%] versus 29 [4.55%] ; P =0.02), and no longer had significantly more falls (27 [4.21%] versus 15 [2.35%] ; P =0.08), bone fractures (23 [3.58%] versus 11 [1.72%] ; P =0.05), or seizures (11 [1.71%] versus 8 [1.25%] ; P =0.64) at 12 months. Conclusions: Fluoxetine 20 mg daily for 6 months after acute stroke had no delayed or sustained effect on functional outcome, falls, bone fractures, or seizures at 12 months poststroke. The lower rate of recurrent ischemic stroke in the fluoxetine group is most likely a chance finding. Registration: URL: http://www.anzctr.org.au/ ; Unique identifier: ACTRN12611000774921.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2021
    detail.hit.zdb_id: 1467823-8
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  • 8
    Online Resource
    Online Resource
    Institute of Electrical and Electronics Engineers (IEEE) ; 2021
    In:  IEEE Access Vol. 9 ( 2021), p. 40076-40085
    In: IEEE Access, Institute of Electrical and Electronics Engineers (IEEE), Vol. 9 ( 2021), p. 40076-40085
    Type of Medium: Online Resource
    ISSN: 2169-3536
    Language: Unknown
    Publisher: Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2021
    detail.hit.zdb_id: 2687964-5
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  • 9
    In: RSC Advances, Royal Society of Chemistry (RSC), Vol. 13, No. 19 ( 2023), p. 13282-13291
    Abstract: Soapberry ( Sapindus mukorossi Gaertn) is a popular woody plant in Vietnam, often used as a cleaning product due to its ability to wash, foam and emulsify due to high saponin content. In this study, the performance of fermentation by two microbial strains, namely Saccharomyces cerevisiae active dry yeast (ADY) and Levilactobacillus brevis lactic acid bacteria (LB) along with the addition of pomelo peel (flavedo) was evaluated during 15 days in terms of sugar removal, antioxidant and antibacterial activities, foaming power, volatile composition, and sensory acceptability. The results showed that the soluble solid content of original extracts experienced a significant decrease from 14.5% to a stable range of 9.4–11.0% until day 15 for all fermented samples, which correlated with a reduction by approximately 60% in reducing sugars (from 12.52 g L −1 to 4.77–6.56 g L −1 ). In addition, the saponin content of fermented extracts was in the range of 118.2–145.0 mg L −1 while antioxidant activities were extremely reduced after 15 days of fermentation. Increases in pomelo peel imparted fermented extracts with greater antibacterial activity against Staphylococcus aureus ATCC 6538, Proteus mirabilis ATCC 25933, and Candida albicans ATCC 10231, and LB had higher activity than ADY overall. Regarding the volatile profiles, two main compounds in the original extracts, including trilaurin (75.02%) and 1-dodecanoyl-3-myristoyl glycerol (24.85%), were completely removed and replaced by new alkanes, alkenes, alcohols, esters, and organic acids, and particularly d -limonene (86.34–95.31%) upon pomelo addition. Additionally, the foaming ability and stability of fermented extracts were also enhanced and there was clear distinction between fermented and unfermented samples using principal component analysis based on sensory liking data which showed consumers' preference towards fermented samples with a high percentage of pomelo peel.
    Type of Medium: Online Resource
    ISSN: 2046-2069
    Language: English
    Publisher: Royal Society of Chemistry (RSC)
    Publication Date: 2023
    detail.hit.zdb_id: 2623224-8
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  • 10
    In: Sensors, MDPI AG, Vol. 22, No. 14 ( 2022-07-06), p. 5082-
    Abstract: A trajectory tracking control for quadcopter unmanned aerial vehicle (UAV) based on a nonlinear robust backstepping algorithm and extended state/disturbance observer (ESDO) is presented in this paper. To obtain robust attitude stabilization and superior performance of three-dimension position tracking control, the construction of the proposed algorithm can be separated into three parts. First, a mathematical model of UAV negatively influenced by exogenous disturbances is established. Following, an extended state/disturbance observer using a general second-order model is designed to approximate undesirable influences of perturbations on the UAVs dynamics. Finally, a nonlinear robust controller is constructed by an integration of the nominal backstepping technique with ESDO to enhance the performance of attitude and position control mode. Robust stability of the closed-loop disturbed system is obtained and guaranteed through the Lyapunov theorem without precise knowledge of the upper bound condition of perturbations. Lastly, a numerical simulation is carried out and compared with other previous controllers to demonstrate the great advantage and effectiveness of the proposed control method.
    Type of Medium: Online Resource
    ISSN: 1424-8220
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2052857-7
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