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  • 1
    In: VNU Journal of Science: Natural Sciences and Technology, Vietnam National University Journal of Science, Vol. 38, No. 1 ( 2022-03-15)
    Abstract: Tóm tắt: Các dẫn xuất azide của isatin là các chất đầu cần thiết cho phản ứng click để tạo ra dị vòng 1,2,3-triazole. Các dẫn xuất N-(ω-bromoalkyl)isatin cần cho chuyển hoá được tổng hợp từ phản ứng thế nucleophile của các isatin tương ứng với các dibromoalkane thích hợp. Một số N-(ω-azidoalkyl)isatin có chứa nhóm thế hoặc không thế ở vòng benzene đã được tổng hợp bằng phản ứng của các N-(ω-bromoalkyl)isatin tương ứng đã tổng hợp được với natri azide. Phản ứng được thực hiện trong DMF khan với sự có mặt của KI với vai trò chất xúc tiến. Hiệu suất sản phẩm đạt được 30−85%. Abstract: Azide derivatives of isatins were the needed initial materials for click chemistry in order to form 1,2,3-triazoles. N-(ω-Bromoalkyl)isatins were prepared by nucleophilic reaction of (un)substituted isatins with appropriate dibromoalkanes. Some ω-azidoalkylisatins were synthesized by reaction of corresponding ω-bromoalkylisatins with sodium azide. The reactions were performed in dry DMF as solvent in the presence of KI as promotive agent. Product yields achived 30−85%.
    Type of Medium: Online Resource
    ISSN: 2588-1140 , 2615-9317
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2022
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  • 2
    In: VNU Journal of Science: Mathematics - Physics, Vietnam National University Journal of Science, Vol. 39, No. 1 ( 2023-03-26)
    Abstract: : In this work, molybdenum disulfide (MoS2) nanorods (NRs) were prepared by a simple hydrothermal method. A sensitive electrochemical glucose biosensor was developed based on the immobilization of glucose oxidase (GOx) on MoS2 NRs modified glassy carbon electrode (GCE). The SnO2 NRs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). SnO2 NRs have large specific area and can load large amounts of GOx molecules. The cyclic voltammetry (CV) of GOx/MoS2 NR/GCE exhibited a linear relationship between the peak current density of CV with glucose concentration in the range of 3.0 mM to 7.0 mM with the limit of detection (LOD) of 3.0 mM and high sensitivity of mA.mM. The parameters affecting the oxidation current density such as pH, temperature, GOx concentration were also investigated. This study demonstrates the feasibility of realizing inexpensive, reliable, and highly effective performance glucose biosensors using MoS2 nanorods.    
    Type of Medium: Online Resource
    ISSN: 2588-1124 , 2615-9341
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2023
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  • 3
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    Online Resource
    Vietnam National University Journal of Science ; 2022
    In:  VNU Journal of Science: Natural Sciences and Technology ( 2022-09-21)
    In: VNU Journal of Science: Natural Sciences and Technology, Vietnam National University Journal of Science, ( 2022-09-21)
    Abstract: This study was conducted to investigate the species composition of Chlorophyta and Charophyta in Bach Ma National Park, Thua Thien Hue province. Here, we identified 45 species and subspecies, belonging to 17 genera, 7 families, and 4 orders. Charophyta was the most diverse phylum, with 75.56% total species. The dominant orders and families are Desmidiales and Desmidiaceae. The most diverse genus belongs to Cosmarium (15), Euastrum (5) and Scenedesmus (5). Micrasterias foliacea Bailey ex Ralfs and Cosmarium pardalis Cohn are tropical algae, while transitional species and temperate species are also present such as Cosmarium pachydermum Lund. var. indicum Iyenf. et Vim Bai and Euastrum jenneri W. Archer, respectively. The dominant group is described as Desmidiales with Chlorococcales (Ch. I) index ranging from 0.087 to 0.19 in Thuy dien Dam and Thuy dien bridge, while there are several species of Sphaeropleales with Ch. I index of 0.67 in Hoang Yen stream.    
    Type of Medium: Online Resource
    ISSN: 2588-1140 , 2615-9317
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2022
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  • 4
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    Online Resource
    Vietnam National University Journal of Science ; 2020
    In:  VNU Journal of Science: Medical and Pharmaceutical Sciences Vol. 36, No. 4 ( 2020-12-19)
    In: VNU Journal of Science: Medical and Pharmaceutical Sciences, Vietnam National University Journal of Science, Vol. 36, No. 4 ( 2020-12-19)
    Abstract: This study aims to evaluate the effectiveness of the use of antibiotic prophylaxis in cesarean section at Thai Nguyen National Hospital as a first pilot activity of a surgical prophylaxis program. In the study, a randomized controlled trial was designed with two groups: intervention group and control group. Patients characteristics and effectiveness of prophylactic antibiotics for caesarean section were compared. The study results show that the patients’ ages ranged from 18 to 44 years; most of the patients had ASA score of 1; and mean hospital length of stay was statistically significant between the two groups (p 〈 0.05). Regarding the indication of caesarean section, the reason of genital tract abnormalities accounted for the highest proportion. The percentage of the patients switching from prophylactic antibiotic regimens to therapeutic antibiotics in the intervention group was 2%. There was no patient with superficial and/or deep incisional surgical site infections in both groups. The difference in mean number of injections in the two groups was statistically significant (p 〈 0.05). The average cost of antibiotics for each patient in the intervention group and control group were 267.720 VND and 543.871 VND, respectively. The study concludes that the effectiveness of antibiotics prophylaxis for caesarean section: 99% of the patients were without wound infection; hospital length of stay in the intervention group was shorter than the control group; and using prophylactic antibiotics was not only more economical but could also reduce the workload of medical staff, costs of antibiotics and medical supplies. Keywords  Antibiotics prophylaxis, caesarean section, Thai Nguyen National Hospital. References [1] Viet Nam Ministry of Health, National guideline on prevention of surgical site infection, issued with Decision No. 3671/QD-BYT, September 27, 2012 of Viet Nam Ministry of Health, Ha Noi, 2012 (in Vietnamese).[2] Viet Nam Ministry of Health, National guideline on antibiotics use, issued with Decision No.708/QD-BYT, March 2, 2015 of Viet Nam Ministry of Health, Ha Noi, 2015 (in Vietnamese).[3] D.W. Bratzler, K.M. Olsen, et al., Clinical Practice Guidelines for Antimicrobial Prophylaxis in Surgery, American Journal of Health-System Pharmacy 70 (2013) 195 – 283. https://doi.org/10.2146/ajhp120568.[4] R.F. Lamont, J.D. Sobel, et al., Current debate on the use of antibiotic prophylaxis for caesarean section, BJOG: An International Journal of Obstetrics & Gynaecology 118 (2011) 193-201. https://doi.org/10.1111/j.14710528.2010.02729.x.[5] T.V. Khai, Infection rate of surgical incisions and associated factors on women after cesarean section at Dong Nai General Hospital, Scientific Research Project of Dong Nai Hospital, 2015 (in Vietnamese).[6] N.H. Tuan, Study on the use of cefazolin to prevent infection after cesarean section or uterine fibroids surgery at the Institute of maternal and neonatal protection, Master’s thesis, Hanoi University of Pharmacy, 2002 (in Vietnamese).[7] F.M. Smaill, R.M. Grivell, Antibiotic prophylaxis versus no prophylaxis for preventing infection after cesarean section, Cochrane Database Syst Rev 10 (2014) CD007482. https://doi.org/10.1002/14651858.cd007482.pub3.    
    Type of Medium: Online Resource
    ISSN: 2588-1132 , 2615-9309
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2020
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  • 5
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    Online Resource
    Vietnam National University Journal of Science ; 2019
    In:  VNU Journal of Science: Natural Sciences and Technology Vol. 35, No. 3 ( 2019-09-20)
    In: VNU Journal of Science: Natural Sciences and Technology, Vietnam National University Journal of Science, Vol. 35, No. 3 ( 2019-09-20)
    Abstract: This paper studies the crystallization process and structure of amorphous iron nanoparticles by molecular dynamics method. The study shows that amorphous iron nanoparticles could not be crystallized at 300 K and 500 K. Iron nanoparticle, annealed at 900 K over a long time, was crystallized into a BCC crystal structure. The structure of crystallized iron nanoparticle at 900 K was analyzed through the pair radial distribution function and the number of crystal atoms upon various regions in nanoparticles. The simulation revealed that the first nuclei was formed most frequently in the area near the surface of the nanoparticle. Then the crystal cluster grew toward the centre of the nanoparticle. The completely crystallized nanoparticle had two components: the core with a BCC crystal structure and surface with an amorphous structure. As for the amorphous nanoparticle at 300 or 500 K, crystal-clusters were too small to grow large enough to crystallize the nanoparticle.   Keywords Iron nanoparticle, crystallize, annealing, crystal atom, crystal cluster. References [1] J.D. Honeycutt, C.H. Andersen, Molecular dynamics study of melting and freezing of small Lennard-Jones clusters, Journal of Physical Chemistry 91 (1987) 4950-4963. https://doi.org/ 10.1021/j100303a014.[2] H. Shin, H.S. Jung, K.S. Hong and J.K. Lee, Crystallization process of TiO2 nanoparticles in an acidic solution, Chemistry letters 33 (2004) 1382-1383. https://doi.org/10.1246/cl.2004. 1382.[3] D. Shi, Z. Li, Y. Zhang, X. Kou, L. Wang, J. Wang, J. Li, Synthesis and characterizations of amorphous titania nanoparticles, Nanoscience and Nanotechnology Letters 1 (2009) 165-170. https://doi.org/10.1166/nnl.2009.1037.[4] D.N. Srivastava, N. Perkas, A. Gedanken, I. Felner, Sonochemical synthesis of mesoporous iron oxide and accounts of its magnetic and catalytic properties, The Journal of Physical Chemistry B 106 (2002) 1878-1883. https://doi. org/10.1021/jp015532w.[5] N. Zaim, A. Zaim and M. Kerouad, The hysteresis behavior of an amorphous core/shell magnetic nanoparticle, Physica B: Condensed Matter 549 (2018) 102-106. https://doi.org/ 10.1016/j.physb. 2017.10.071.[6] L. Gao and Q. Zhang, Effects of amorphous contents and particle size on the photocatalytic properties of TiO2 nanoparticles, Scripta materialia 44 (2001) 1195-1198. https://doi.org/ 10. 1016/S1359-6462(01)00681-9.[7] G. Madras, B.J. McCoy, Kinetic model for transformation from nanosized amorphous TiO2 to anatase, Crystal growth & design 7 (2007) 250-253. https://doi.org/10.1021/cg060272z.[8] C.I. Wu, J.W. Huang, Y.L. Wen, S.B. Wen, Y.H. Shen, M.Y. Yeh, Preparation of TiO2 nanoparticles by supercritical carbon dioxide, Materials Letters 62 (2008) 1923-1926. https://doi.org/10. 1016/j.matlet.2007.10.043.[9] C. Pan, P. Shen and S.Y. Chen, Condensation and crystallization and coalescence of amorphous Al2O3 nanoparticles, Journal of crystal growth 299 (2007) 393-398. https://doi.org/ 10. 1016/j.jcrysgro.2006.12.006.[10] M. Epifani, E. Pellicer, J. Arbiol, N. Sergent, T. Pagnier, J.R. Morante, Capping ligand effects on the amorphous-to-crystalline transition of CdSe nanoparticles, Langmuir 24 (2008) 11182-11188. https://doi.org/10.1021/la801859z.[11] P.H. Kien, M.T. Lan, N.T. Dung, P.K. Hung, Annealing study of amorphous bulk and nanoparticle iron using molecular dynamics simulation. International Journal of Modern Physics B 28 (2014) 1450155 (17 page). https:// doi.org/10.1142/S0217979214501550.[12] V.V. Hoang and N.H. Cuong, Local icosahedral order and thermodynamics of simulated amorphous Fe. Physica B: Condensed Matter 404 (2009) 340-346. https://doi.org/10.1016/ j.physb. 2008.10.057.        
    Type of Medium: Online Resource
    ISSN: 2588-1140 , 2615-9317
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2019
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  • 6
    In: VNU Journal of Science: Natural Sciences and Technology, Vietnam National University Journal of Science, Vol. 37, No. 3 ( 2021-09-22)
    Abstract: As a part of ongoing efforts to exploit the pharmaceutical potential of domestic cyanobacteria, six strains belonging to the Nostocales order have been isolated from several sampling sites in Ha Noi as prerequisite material. The cytotoxic activity evaluation based on the MTT test resulted in four extracts from two strains (NK7 and NK1111) exhibiting the inhibitory activity against HeLa cells, with IC50 values ranging from 84.6 µg/mL to 257.3 µg/mL. In addition, the bioassay-guided isolation of the HK7 methanol extract led to one cytotoxic activity K3 fraction possessing two natural compounds. Compounds 1 showed the accurate mass of 352.2633 Da with the formula of C21H36O4 similar to three cytotoxic compounds 7Z-plakortide H, 10-gingerdiol, and ebelactone B. Compound 2 had the accurate mass of 278.1545 Da with the formula of C16H22O4 similar to four cytotoxic compounds pestaloficiol G, penicitrinol E-D, and isoversiol C.
    Type of Medium: Online Resource
    ISSN: 2588-1140 , 2615-9317
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2021
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  • 7
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    Online Resource
    Vietnam National University Journal of Science ; 2020
    In:  VNU Journal of Science: Earth and Environmental Sciences Vol. 36, No. 2 ( 2020-06-24)
    In: VNU Journal of Science: Earth and Environmental Sciences, Vietnam National University Journal of Science, Vol. 36, No. 2 ( 2020-06-24)
    Abstract: Holocene environment change in Hai Phong coastal area was reconstructed based on diatom and grain-size analysis in the HP1 core at Duong Kinh, Hai Phong. 52 diatom species were identified and divided in five diatom ecozones by changing of four diatom groups including marine planktonic, brackish planktonic, brackish benthic and freshwater one. The sedimentary environment at the Hai Phong coastal area was estuary- bay condition in the Flandrian trangression (Z1, Z2 and Z3 Unit). Deltaic environment changed from prodelta (Z4), delta front (Z5) to delta plain (Z6 and Z7) corresponding to the Flandrian regression.
    Type of Medium: Online Resource
    ISSN: 2588-1094 , 2615-9279
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2020
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  • 8
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    Online Resource
    Vietnam National University Journal of Science ; 2023
    In:  VNU Journal of Science: Natural Sciences and Technology Vol. 39, No. 1 ( 2023-03-03)
    In: VNU Journal of Science: Natural Sciences and Technology, Vietnam National University Journal of Science, Vol. 39, No. 1 ( 2023-03-03)
    Abstract: In this study, the structural characteristics of a polysaccharide extracted from the Ulva fasciata green seaweed were determined using the chemical composition analytical methods combined with IR, MS, and NMR spectra. The results showed that the polysaccharide consists of two major repeating disaccharide units designated as ulvanobiuronic acid 3-sulfate type A (A3s) [→4)-β-D-GlcA-(1 → 4)-α-L-Rha 3S-(1→] and type B (B3s) [→4)-α-LIdoA-(1 → 4)-α-L-Rha 3s(1→] . This kind of polysaccharide exhibited a significant in vitro antioxidant activity. This study demonstrated that the Ulva fasciata green algae can be considered as a source of bioactive ulvan.
    Type of Medium: Online Resource
    ISSN: 2588-1140 , 2615-9317
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2023
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  • 9
    In: VNU Journal of Science: Natural Sciences and Technology, Vietnam National University Journal of Science, ( 2022-12-03)
    Abstract: In this paper, some new polythiophenes containing benzo[d]thiazole heterocycle were synthesized by the oxidative polymerization in chloroform using iron(III) chloride as a catalytic oxidant. Infrared (IR) spectroscopy and ultraviolet–visible (UV-Vis) spectroscopy analyses confirmed that the polymerization reaction successfully took place and the absorption band at 497 nm is typical for π–π* transition in the conjugated polythiophenes. The polymers are composed of relatively uniform particles using field emission scanning electron microscopy (FESEM) method. Based on thermal gravimetric analysis (TGA), the polymers had average thermal stability in the atmosphere when decomposed completely at 500 oC. The polymers exhibited fluorescence emission at about 516 nm due to the conjugated chain in the polymers.
    Type of Medium: Online Resource
    ISSN: 2588-1140 , 2615-9317
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2022
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  • 10
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    Online Resource
    Vietnam National University Journal of Science ; 2017
    In:  VNU Journal of Science: Medical and Pharmaceutical Sciences Vol. 33, No. 2 ( 2017-12-04)
    In: VNU Journal of Science: Medical and Pharmaceutical Sciences, Vietnam National University Journal of Science, Vol. 33, No. 2 ( 2017-12-04)
    Abstract: CYP2C19 is one of the pricipal enzymes involed in the antiplatelet prodrug in patients with acute myocardial infraction. Different genotypes can cause various responses to platelet aggregation inhibitors. Therefore, we conduct research to evaluate the relationship between CYP2C19 polymorphisms and platelet aggregation in patients with acute myocardial infraction. The study was processed with a cross-sectional study of patients diagnosed acute myocardial infraction had blood samples tested for the gene CYP2C19 and platelet aggregation. The results in 64 consecutive patients, phenotypes based on genotypes: 59,3% poor and intermediate metabolizer, 40,7% extensive metabolizer. The average platelet aggregation of (poor, intermediate) metabolizer and extensive metabolizer were 29,79±13,6 and 23,27±11,6, respectively, there was a high similarity between the groups (p 〉 0,05). The average platelet aggregation of (poor, intermediate) metabolier and extensive metabolizer on the group with Clopidogrel were 26,2±10,5 and 29,9±13,6 (p 〉 0,05), the average with Ticagrelor were 10,8±6,5 and 18,4±8,7 (p 〉 0,05), respectively. The group treated with Ticagrelor had a lower platelet aggregation than the remaining one with Clopidogrel (p 〈 0,01). The study got some initial results that would be important for further studies on the relationship between CYP2C19 polymorphisms and platelet aggregation on Viet Namese patients with acute myocardial infraction.
    Type of Medium: Online Resource
    ISSN: 2588-1132 , 2588-1132
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2017
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