Argyreia gyrobracteata Traiperm & Chitchak (Convolvulaceae): A new record to the flora of Vietnam

Binh Duc TRAN,Bach The TRAN,Do Van Hai,Quang Hong BUI,Son Hoang DOAN,Han Ngoc LE,Thuy Thu NGUYEN,엄상미 한국식물분류학회 2020 식물 분류학회지 Vol.50 No.3

Argyreia gyrobracteata Traiperm & Chitchak (Convolvulaceae) is newly recorded in Vietnam. It is similar to A. mekongensis Gagnep & Courch in having a white campanulate corolla but differs from that species by having whitish surface of the abaxial leaf, narrowly lanceolate or linear-oblong, curly, rolled up the bract with a longer length of the petiole and a shorter pedicel. It was previously known only in Thailand, but was recently found in Lam Dong Province, Vietnam, for the first time. The present study provides a detailed description, colorful photos and the distribution of the species. Furthermore, a comparison of the diagnostic characters between this species and a related species in Vietnam, A. mekongensis Gagnep & Courch, is provided.

Development of label-free electrochemical lactose biosensor based on graphene/poly(1,5-diaminonaphthalene) film

Binh Hai Nguyen,Binh Thanh Nguyen,Hanh Van Vu,Chuc Van Nguyen,Dzung Tuan Nguyen,Loc Thai Nguyen,Thu Thi Vu,Lam Dai Tran 한국물리학회 2016 Current Applied Physics Vol.16 No.2

In this work, a lactose biosensor was developed by co-immobilizing b-galactosidase (b-Gal) and glucose oxidase (GOx) on microelectrodes pre-modified with Pt/graphene/P(1,5-DAN) for estimation of lactose in dairy products to prevent lactose intolerance. The Pt microelectrode was modified with graphene and 1,5-polydiaminonaphthalene film. Graphene was synthesized by chemical vapor deposition on copper tape and manually transferred to the electrode surface. Polymeric P(1,5-DAN) was grafted on top of the graphene film by electropolymerization. Modified surface of the electrode was characterized by Raman spectra analysis, FE-SEM, AFM and cyclic voltammetry. The results indicated that deposition graphene film on electrode surface induced considerable enhancement in current signal, over 20 times as high as the uncoated electrode surface. The developed sensor was successfully used to determine lactose in model samples with sensitivity, correlation coefficient (R2) and limit of detection (LOD) estimated to be 1.33 mA/(mgml1), 0.995 and 1.3 mg/ml, respectively. The combined graphene and conductive P(1,5-DAN) could serve as a novel sensing platform on electrochemical sensors with superior sensitivity.

Tripterygium wilfordii (Celastraceae): A new generic and species record for the flora of Vietnam

Do Van Hai,Bui Hong Quang,Tran The Bach,Tran Duc BINH,Ritesh Kumar Choudhary,이중구 한국식물분류학회 2021 식물 분류학회지 Vol.51 No.3

Tripterygium wilfordii Hook.f. (Celastraceae), collected from Phia Oac-Phia Den National Park of Vietnam, is reported here as a new generic and species record for the flora of Vietnam. The genus Tripterygium differs from other genera of Celastraceae by its samara fruits, which become three-winged at maturity, and a scandent shrub. Taxonomic notes, descriptions, line drawing and photographs are provided, together with short notes on the distribution, ecology and phenology of Tripterygium wilfordii Hook.f. (Celastraceae).

Carbon coated MFe2O4 (M=Fe, Co, Ni) magnetite nanoparticles: A smart adsorbent for direct yellow and moderacid red dyes

Hoang Vinh Tran,Hai Van Nguyen,Doanh Viet Vu,Thu Dieu Le,Binh Thanh Nguyen,Dang Hai Le 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.2

We report here a simple approach for synthesis of carbon coated magnetite (C@MFe2O4, M=Co, Ni, Fe) with shell@core nanostructured composites that we used as magnetic-nanosorbents for direct yellow (DYG) and moderacid red (RS) as pollutant textile dyes removal via an adsorption process. The synthesized C@MFe2O4 was characterized by TEM, SEM, EDX, XRD, FT-IR and VSM techniques. TEM results indicated that C@MFe2O4 nanocomposites have 20-30 nm of MFe2O4 nanoparticle core and 2-3 nm in thickness of the amorphous carbon shell. The synthesized C@MFe2O4 nanocomposites have the zero point charge (pHZPC) at 5.5, which suggests that DYG and RS, anionic dyes can be adsorbed onto the C@MFe2O4 nanosorbents in the acidic medium. Adsorption of DYG and RS onto magnetic nanosorbents was optimized and adsorption thermodynamic parameters were evaluated, clearly indicating that the adsorption of RS onto synthesized magnetic-nanosorbents was facile more than that DYG. The adsorption isotherm data showed that the adsorption processes of DYG and RS onto Fe3O4 or C@MFe2O4 nanosorbents are more suitable for the Langmuir model than Freundlich model. The maximum adsorption capacity (qmax) of DYG dye onto Fe3O4, C@Fe3O4 and C@CoFe2O4 adsorbents was 14.641, 36.232 and 7.85mg g1, respectively; meanwhile, these values were 41.152, 61.728 and 39.683mg g1 for RS dye. These obtained data indicate that the developed Fe3O4, C@Fe3O4 and C@CoFe2O4 nanoparticles can be used as recoverable and recyclable adsorbents for not only organic pigments adsorption but also for heavy metal ion removal or protein extraction as well.

Clerodendrum ervatamioides (Lamiaceae): A new record to the flora of Vietnam

Heyjoong KIM,Do Van Hai,Tran Duc THIEN,Tran The Bach,Bui Hong Quang,Duong Thi HOAN,Le Ngoc HAN,Tran Duc BINH,Ritesh Kumar Choudhary,이중구 한국식물분류학회 2022 식물 분류학회지 Vol.52 No.4

Clerodendrum ervatamioides C. Y. Wu was described in 1977 with its type locality in Yunnan, China. During our floristic investigation in the Muong Nhe Nature Reserve of Vietnam of Dien Bien province and in the Muong Te district of the Lai Chau province, we collected several specimens of Clerodendrum ervatamioides, marking the first record of its occurrence in Vietnam. In this paper, details of the morphological features, distribution, ecology, photo plates, and a table comparing the morphological features with its ally Clerodendrum garrettianum Craib are provided.

Self-antibacterial chitosan/Aloe barbadensis Miller hydrogels releasing nitrite for biomedical applications

Thai Thanh Hoang Thi,Binh D.T. Trinh,Phuong Le Thi,Dieu Linh Tran,박기동,Dai Hai Nguyen 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.103 No.-

Because of the toxic glutaraldehyde, the chitosan-glutaraldehyde hydrogels are seriously limited inbiomedical applications. In this study, exploiting bioactive compounds of Aloe barbadensis Miller, the chitosan/Aloe barbadensis Miller-glutaraldehyde (CS/AV-GDA) hydrogels were fabricated with 4-fold lowerglutaraldehyde concentration without compromising hydrogel characteristics. The gelation time wascontrolled from a few seconds to several hours. The elastic modulus was varied from 483 to 99940 Pa. The CS/AV-GDA hydrogels could release the natural nitrite amount from 24.0 to 89.6 lM within the firsthour for antibacterial activity, then continuously deliver a few lM every next hour for cell activities. Theantibacterial test against Escherichia coli and Staphylococcus aureus revealed that the CS/AV-GDA hydrogelscould kill the planktonic bacteria 5-fold more highly than control and prevent bacteria attachmenton hydrogel surface effectively. Although the CS/AV-GDA hydrogels consumed only 0.25% glutaraldehydeconcentration, their antibacterial capacities were comparable to chitosan-only hydrogels with 2% glutaraldehyde. For cytotoxicity tests, the CS/AV-GDA hydrogels using 0.25% glutaraldehyde concentrationinduce the human dermal fibroblasts proliferation significantly. All CS/AV-GDA hydrogels with glutaraldehydecrosslinker less than 1% showed non-cytotoxicity. As a result, the new CS/AV-GDA hydrogelsmight become an attractive candidate for medicine regeneration and tissue engineering.

Intelligent Charger with Online Battery Diagnosis Function

Van-Tuan Doan,Van-Binh Vu,Hai-Nam Vu,Duc-Hung Tran,Woojin Choi 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

In the battery based applications, the performance of the system highly depends on the reliability of the battery. However, it is difficult to obtain the accurate information about the state-of-health (SOH) of battery during its operation. In this paper a 3kw battery charger with online battery diagnosis function which can estimate the SOH of the battery by using online impedance spectroscopy technique is introduced. For the charger, a phase shift full bridge converter with synchronous rectification has been adopted to implement constant current/constant voltage charge and diagnosis functions. The electrochemical impedance spectroscopy (EIS) is performed after the charge to obtain the information about the internal impedance of the battery module, hence the SOH can be estimated online by observing the impedance variation of the battery over time. All the design procedure of the proposed charger is detailed and the feasibility of the system is verified by the experimental results.

Facile synthesis of multifunctional Ag/Fe3O4-CS nanocomposites for antibacterial and hyperthermic applications

Ngoan Thi Nguyen,Dai Lam Tran,Duc Cuong Nguyen,Thai Loc Nguyen,Thi Cham Ba,Binh Hai Nguyen,Thi Duong Ba,Nam Hong Pham,Dzung Tuan Nguyen,Thai Hoa Tran,Gia Dien Pham 한국물리학회 2015 Current Applied Physics Vol.15 No.11

Nanocomposites containing two or more functional constituents are attractive candidates for advanced nanomaterials. In this study, multifunctional Ag/Fe3O4-CS nanocomposites were successfully prepared, using chitosan as a stabilizing and cross-linking agent. The as-synthesized nanocomposites were characterized by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS), UVevisible spectrophotometer (UVeVis) and vibrating sample magnetometer (VSM). The results demonstrated that Ag/Fe3O4-CS composite nanoparticles (NPs) were composed of parent components, Fe3O4 and Ag NPs, which were uniformly dispersed in the chitosan matrix. The hybrid NPs exhibited strong antibacterial property against Pseudomonas aeruginosa. With high magnetization value (67 emu/g), the synthesized Ag/Fe3O4-CS composite can be easily separated or recycled in potential biomedical applications. Furthermore, the results showed that the multicomponent hybrid nanostructures appeared to be the promising material for local hyperthermia, which can be used as thermoseeds for localized hyperthermia treatment of cancers.

Management of Antibiotic-Resistant Helicobacter pylori Infection: Perspectives from Vietnam

Vu Van Khien,Duong Minh Thang,Tran Manh Hai,Nguyen Quang Duat,Pham Hong Khanh,Dang Thuy Ha,Tran Thanh Binh,Ho Dang Quy Dung,Tran Thi Huyen Trang,Yoshio Yamaoka 거트앤리버 소화기연관학회협의회 2019 Gut and Liver Vol.13 No.5

Antibiotic resistance is the most important factor leading to the failure of eradication regimens. This review focuses on the prevalence of Helicobacter pylori primary and secondary resistance to clarithromycin, metronidazole, amoxicillin, levofloxacin, tetracycline, and multidrug in Vietnam. We searched the PubMed, EMBASE, Vietnamese National Knowledge Infrastructure, and Vietnamese Biomedical databases from January 2000 to December 2016. The search terms included the following: H. pylori infection, antibiotic (including clarithromycin, metronidazole, amoxicillin, levofloxacin, tetracycline, and multidrug) resistance in Vietnam. The data were summarized in an extraction table and analyzed manually. Finally, Excel 2007 software was used to create charts. Ten studies (three studies in English and seven in Vietnamese) were included in this review. A total of 308, 412, 523, 408, 399, and 268 H. pylori strains were included in this review to evaluate the prevalence of H. pylori primary resistance to amoxicillin, clarithromycin, metronidazole, levofloxacin, tetracycline, and multidrug resistance, respectively. Overall, the primary resistance rates of amoxicillin, clarithromycin, metronidazole, levofloxacin, tetracycline, and multidrug resistance were 15.0%, 34.1%, 69.4%, 27.9%, 17.9% and 48.8%, respectively. Secondary resistance rates of amoxicillin, clarithromycin, metronidazole, levofloxacin, tetracycline, and multidrug resistance were 9.5%, 74.9%, 61.5%, 45.7%, 23.5% and 62.3%, respectively. In Vietnam, primary and secondary resistance to H. pylori is increasing over time and affects the effectiveness of H. pylori eradication.

Effects of Injection Molding Parameters and their Interactions on Mechanical Properties of PMMA/PC Blend

Hoang, Van Thanh,Luu, Duc Binh,Toan Do, Le Hung,Tran, Ngoc Hai,Nguyen, Pham The Nhan,Tran, Minh Sang,Tran, Minh Thong Materials Research Society of Korea 2020 한국재료학회지 Vol.30 No.12

A combination of Polycarbonate (PC) material and Polymethylmethacrylate (PMMA), fabricated using an injection molding machine, has been investigated to determine its advantages, as studied in Ref. 1). This paper aims to investigate the optimization of PMMA/PC blend for both tensile yield strength and impact strength. Furthermore, interaction effects of process conditions on mechanical properties including tensile yield strength and impact strength of PMMA/PC blend by injection molding process are interpreted in this study. Tensile and impact specimens are designed following ASTM, type V, and are fabricated by injection molding process. The processing conditions such as melt temperature, mold temperature, packing pressure, and cooling time are applied; each factor has three levels. As a result, in comparison with optimization of separated responses, mechanical properties of PMMA/PC are found to decrease when optimizing both tensile and impact strengths simultaneously. The melt temperature is found to be the most significant interaction parameter with the mold temperature and packing pressure. In addition, there is more interaction between the mold temperature and cooling time. This investigation provides a useful understanding of the control of injection molding processing of polymer blends in optical application.