Journal Articles - Natural Science - 2021

Permanent URI for this collection

http://repository.vlu.edu.vn:443/handle/123456789/114

Browse

Browsing Journal Articles - Natural Science - 2021 by Issue Date

Jump to a point in the index:
  • Publication
    A molecular docking simulation study on potent inhibitors against Rhizoctonia solani and Magnaporthe oryzae in rice: silver-tetrylene and bis-silver-tetrylene complexes vs. validamycin and tricyclazole pesticides
    ( 2020)
    Bui Thi Phuong Thuy
    ;
    Tran Thi Ai My
    ;
    Nguyen Thi Thanh Hai
    ;
    Huynh Thi Phuong Loan
    ;
    Le Trung Hieu
    ;
    Tran Thai Hoa
    ;
    Thanh Q. Bui
    ;
    Ho Nhat Tuong
    ;
    Nguyen Thi Thu Thuy
    ;
    Doan Kim Dung
    ;
    Pham Van Tat
    ;
    Phan Tu Quy
    ;
    Nguyen Thi Ai Nhung
    Rice, well known as the most important staple food source worldwide, is highly susceptible to many infectious diseases, especially rice sheath blight caused by fungus Rhizoctonia solani and rice blast caused by fungus Magnaporthe oryzae. The inhibitory ability of silver- and bis-silver-tetrylene complexes, including Ag-E and bis-Ag-E with E = C, Si, Ge, onto protein 4G9M in Rhizoctonia solani and protein 6JBR in Magnaporthe oryzae was theoretically investigated using molecular docking simulation methodology. Two commercial pesticides selected as inhibitory references are validamycin for 4G9M and tricyclazole for 6JBR. The results reveal that bis-silver-tetrylene complexes perform the strongest inhibitory effects towards both proteins. The structures of the complexes exhibit good site–site binding to both proteins given the observations on the hydrogen bond interactions, cation–π bonds, π–π bonds, and ionic interactions, interaction distance between amino acids and ligands, and van der Waals interactions. The inhibitory capacity onto protein 4G9M decreases in the following order: bis-Ag-C > bis-Ag-Si > bis-Ag-Ge > validamycin > Ag-C ≈ Ag-Si ≈ Ag-Ge. The corresponding order observed from the study for protein 6JBR is bis- Ag-C > bis-Ag-Si ≈ bis-Ag-Ge > tricyclazole ≈ Ag-C ≈ Ag-Si ≈ Ag-Ge. The study opens a promising approach to tackle rice blast and rice sheath blight based on a family of silver-tetrylene organometallic chemicals given the theoretical proof of environment-advanced properties and molecule-scaled effectiveness.
  • Publication
    Site occupancy and phonon sideband of trivalent europium doped calcium aluminosilicate phosphors
    ( 2021)
    Nguyen Thi Quynh Lien
    ;
    Ho Van Tuyen
    ;
    Nguyen Ha Vi
    ;
    A.N.H. Thuan
    ;
    Phan Van Do
    A series of Eu3+ doped Ca2Al2SiO7 were synthesized by the solid-state reaction method. Structural and luminescent properties of the obtained samples were investigated through X-ray diffraction, Raman and luminescence spectra. The luminescent characteristic of the 5D0 → 7F0,1 transitions from emission spectra of Eu3+ ions showed that the Eu3+ ions occupy at two different sites in Ca2Al2SiO7 lattice. The Ca2Al2SiO7:Eu3+ red phosphors have three phonon sidebands with energies ~673 cm􀀀 1, 848 cm􀀀 1 and 1443 cm􀀀 1 which have been determined via the excitation spectra of Eu3+ ions in Ca2Al2SiO7 materials. These obtained phonon energies coincided with the vibrational energies observed from Raman spectra. The multiphonon relaxation rates for the excited levels of 5D1, 5D2 and 5D3 of Eu3+ ions in Ca2Al2SiO7 were also calculated.
  • Publication
    Two new cycloartanes from the leaves of Combretum quadrangulare growing in Vietnam and their biological activities
    ( 2021)
    Huu-Hung Nguyen
    ;
    Thi-Phuong Nguyen
    ;
    Nguyen Tien Trung
    ;
    Cam-Tu D. Phan
    ;
    Thi-Bich-Ngoc Dao
    ;
    Dinh-Tri Mai
    ;
    Jirapast Sichaem
    ;
    Ngoc-Hong Nguyen
    ;
    Cong-Luan Tran
    ;
    Thuc-Huy Duong
    Two novel cycloartanes, combretanones G and H (1 and 2), were isolated from the leaves of Combretum quadrangulare. Their structures were elucidated by applying a set of spectroscopic methods, while their relative configurations were determined using DFT-NMR chemical shift calculations and subsequent assignment of DP4 probabilities. Compounds 1 and 2 are C-23/C-24 stereoisomers of the previously-reported euphonerin E. Both exhibited moderate cytotoxicity against three human cancer cell lines. Compound 2 was shown to be a potent antiparasitic. Our results confirm the traditional medicinal uses of Combretum quadrangulare in Vietnam.
  • Publication
    Alpha-Glucosidase Inhibitory Diterpenes from Euphorbia antiquorum Growing in Vietnam
    ( 2021)
    Cong-Luan Tran
    ;
    Thi-Bich-Ngoc Dao
    ;
    Thanh-Nha Tran
    ;
    Dinh-Tri Mai
    ;
    Thi-Minh-Dinh Tran
    ;
    Nguyen-Minh-An Tran
    ;
    Van-Son Dang
    ;
    Thi-Xuyen Vo
    ;
    Thuc-Huy Duong
    ;
    Jirapast Sichaem
    Bioactive-guided phytochemical investigation of Euphorbia antiquorum L. growing in Vietnam led to the isolation of five ent-atisanes, one seco-ent-atisane, and one lathyrane (ingol-type). The structures were elucidated as ent-1α,3α,16β,17-tetrahydroxyatisane (1), ethyl ent-3,4-seco-4,16β,17-trihydroxyatisane-3-carboxylate (2), ent-atisane-3-oxo-16β,17-acetonide (3), ent-3α-acetoxy-16β,17-dihydroxyatisane (4), ent-16β,17-dihydroxyatisane-3-one (5), calliterpenone (6), and ingol 12-acetate (7). Their chemical structures were unambiguously determined by analysis of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) and high resolution mass spectrometry, as well as by comparison with literature data. Among them, 1 is a new compound while 2 is an ethylated artifact of ent-3,4-seco-4,16β,17-trihydroxyatisane-3-carboxylic acid, a new compound. Isolates were evaluated for alpha-glucosidase inhibition. Compound 3 showed the most significant inhibitory activity against alpha-glucosidase with an IC50 value of 69.62 µM. Further study on mechanism underlying yeast alpha-glucosidase inhibition indicated that 3 could retard the enzyme function by noncompetitive.
  • Publication
    Applying SiO<sub>2</sub> nano-particles for improving optical properties of WLED conformal and in-cup structures
    ( 2021)
    Phan Xuan Le
    ;
    Pham Quang Minh
    This article is the analysis of SiO2 nano-particles’ influences on the luminous efficiency and the color temperature uniformity of a remote phosphor structure in a WLED. The purpose of integrating SiO2 into the silicone layer in the remote phosphor structure is to significantly promote the scattering occurrences. Particularly, with an appropriate proportion of SiO2, there could be more blue lights generated at large angles, leading to reducing the angular-dependent color temperature deviation. The luminous flux also can get benefits from SiO2 addition owing to a proper air-phosphor layer refractive index ratio provided by this SiO2/silicone compound. The attained experimental results were compared with optical values of a non-SiO2 remote phosphor configuration and showed a notable enhancement. The color deviation was reduced by approximately 600 K in the angles from -700 ­to 700. Additionally, the lumen efficiency was improved by 2.25% at 120 mA driving current. Hence, SiO2 can be used to boost both color uniformity and luminous efficacy for remote-phosphor WLED.
  • Publication
    Effects of air temperature and blanching pre-treatment on phytochemical content, antioxidant activity and enzyme inhibition activities of Thai basil leaves (Ocimum basilicum var. thyrsiflorum)
    ( 2021)
    N.L. Le
    ;
    T.T.H. Le
    ;
    N.B. Ma
    Thai basil leaves (Ocimum basilicum var. thyrsiflorum) have been used in food flavoring and traditional medicine. Hot-air drying is a convenient and low-cost method to preserve them for long-term use but causes the loss of their bioactive compounds during the process. In this work, the effect of pre-blanching on preserving these characteristics of Thai basil leaves dried at different air temperatures was studied. The antioxidant characteristics were evaluated by the contents of total phenolics, total flavonoids and total chlorophylls and the scavenging capacity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. In addition, the inhibitory activities against starch-digesting enzymes were assessed with α-amylase and amyloglucosidase. At the air temperature of 50oC, antioxidant characteristics of dried leaves with pre-blanching were proven better than those without blanching and came close to those of the fresh sample. The drying temperature had more evident effects on inhibitory activities against starch-digesting enzymes than blanching. These activities of hot-air dried leaves were comparable to those of the fresh one. This study could provide insights into the integration of blanching and hot-air drying to preserve medicinal plants.
  • Publication
    Temperature Effect of Water Coagulation Bath on Chitin Fiber Prepared through Wet-Spinning Process
    ( 2021)
    Khoa Dang Nguyen
    Chitin was chemically extracted from crab shell waste and dissolved in N,N-dimethyl acetamine/5% lithium chloride (DMAc/5% LiCl) at room temperature to obtain 1% and 2% concentrations of chitin solution. Chitin fibers were prepared by phase inversion at different temperatures of water coagulation bath at 5, 20, and 60 °C. The deconvolution of FTIR spectra indicated that the area portion of the intermolecular hydrogen bonding NH…OC increased at 60 °C due to the higher density of the chitin segment in the fiber. As a result, scanning electron microscope (SEM) measurement suggests that a denser structure of the chitin fiber was observed when the temperature of the coagulation bath increased. In addition, the resultant chitin fibers generated better mechanical properties relative to the amount of chitin concentration and temperature. At 2% of chitin solution, the tensile strength significantly increased from 80 to 182 MPa for the fiber obtained at temperatures of 5 and 60 °C of the water coagulation bath, respectively. Meanwhile, the water content in the fiber significantly decreased from 1101% to 335%. This green synthesis route has high potential for the fabrication of the fiber as future material of interest for biomedical application.
  • Publication
    Electrochemical Determination of Uric Acid in Urine by Using Zeolite Imidazolate Framework-11 Modified Electrode
    ( 2021)
    Tran Si Thanh
    ;
    Phan Tu Qui
    ;
    Nguyen Thi Thanh Tu
    ;
    Tran Thanh Tam Toan
    ;
    Tran Thi Bich Hoa
    ;
    Le Van Thanh Son
    ;
    Do Mai Nguyen
    ;
    Tran Ngoc Tuyen
    ;
    Dinh Quang Khieu
    ;
    Thanh-Danh Nguyen
    In the present article, the synthesis of zeolite imidazole framework-11 (ZIF-11) by ultrasonic-assisted hydrothermal process and its application as an electrode modifier for electrochemical determination of uric acid in urine are demonstrated. The obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and nitrogen adsorption/desorption isotherms. It was found that the ZIF-11 with rhombic dodecahedron topology and high surface area (1066m2.g-1) was synthesized in a certain temperature and found in around 25–40°C, and other crystalline phases of zinc benzimidazolate deferring from ZIF-11 phase were found in less 25°C or higher than 40 ° C. The ZIF-11 is stable in the pH range 6-10. The modification of glassy carbon electrode was performed with ZIF-67 using the drop-casting procedure. The present ZIF-11 modified electrode was employed to study the electrochemical behavior of uric acid (UA). UA oxidation is catalyzed by this electrode in aqueous buffer solution (pH7) with a decrease of 70mV in overpotential compared to glassy carbon electrode. With the differential pulse–anodic stripping voltammetry (DP-ASV) method, the oxidation current of UA versus its concentration shows good linearity in the range 20– 540μM (R = 0:998) with a detection limit of 0.48 μM (S/N = 3). The obtained ZIF-11 modified electrode was applied in the detection of UA content in urine samples, and satisfied results were obtained.
  • Publication
    Nickel ferrite: synthesis and application for voltammetric determination of uric acid
    ( 2021)
    Nguyen Thi Vuong Hoan
    ;
    Nguyen Ngoc Minh
    ;
    Nguyen Thi Lieu
    ;
    Nguyen Van Thang
    ;
    Vo Thang Nguyen
    ;
    Nguyen Thi Thanh Tu
    ;
    Tran Thanh Tam Toan
    ;
    Nguyen Hoang Tuan
    ;
    Duong Quang Nhan
    ;
    Ho Van Minh Hai
    ;
    Tran Ngoc Tuyen
    ;
    Dinh Quang Khieu
    In this paper, the synthesis of nickel ferrite and its use for voltammetric determination of uric acid (UA) are presented. Nickel ferrite was synthesized via a hydrothermal process using spherical carbons as hard template followed by calcination at 500 °C. It was found that iron and nickel compositions in nickel ferrite can be controlled by the initial Fe/Ni molar ratio. The stoichiometric nickel ferrite (NiFe2O4) with hollow spherical morphology was obtained from a reaction mixture with Fe/Ni molar ratio of around 1.2–1.5. Glassy carbon electrode modified with nickel ferrite was employed to quantitatively determine UA by different pulse voltammetric method. Under the optimum conditions, the anodic peak current was linearly proportional to UA concentration in the range of 0.398 to 6.761 μM. The detection limit (3σ) was found to be 0.15 μM. The proposed method has been employed to determine UA in human urine samples with acceptable recoveries of 95.15–104.8%. On the other hand, the results obtained from this method were also compared with that from standard HPLC method, showing no statistical difference.
  • Publication
    Evaluation of fatty acids, phenolics and bioactivities of spent coffee grounds prepared from Vietnamese coffee
    ( 2021)
    Danh C. Vu
    ;
    Quyen T. Vu
    ;
    Long Huynh
    ;
    Chung-Ho Lin
    ;
    Sophie Alvarez
    ;
    Xuyen T. Vo
    ;
    Trang H. D. Nguyen
    Spent coffee ground (SCG) is a residue released during coffee brewing. Disposal of SCG is able to lead to a loss of bioactive constituents and have a negative impact upon the environment. This study aimed to explore fatty acids, bioactive phenolics, antioxidant and anti-aging potentials of SCG samples obtained from coffee shops in Ho Chi Minh city, Vietnam. The oil content of the SCG samples ranged from 6.3 to 10.5%, and linoleic (43%), palmitic (33.4%) and oleic (11%) acids were identified as major constituents of the oil. Chlorogenic acid was the most abundant phenolic acid examined (832.9–7657.7 μg/g of dry weight), followed by ferulic acid (40.5–1041.7 μg/ g). Through anti-collagenase and anti-elastase assays, SCG showed a promising anti-aging activity, with IC50 values comparable with those of epigallocatechin gallate. The correlation analysis revealed gallic acid positively correlated with the free radical scavenging potential evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) assay and the inhibitory effect on elastase. The results demonstrated that utilization of SCG prepared from Vietnamese coffee could open new avenues for food and cosmeceutical industry.
  • Publication
    Synthesis, characterization, and caesium adsorbent application of trigonal zinc hexacyanoferrate (II) nanoparticles
    ( 2021)
    Nguyen Dinh Trung
    ;
    Ning Ping
    ;
    Le Thi Ha Lan
    ;
    Ho Kim Dan
    Trigonal zinc hexacyanoferrate (TZHF) nanoparticle adsorbents for effective caesium ion (Cs+) removal were prepared using the chemical coprecipitation method. The morphologies of zinc hexacyanoferrate (ZHF) were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), and energy-dispersive X-ray spectroscopy (EDS). These analyses confirmed that the trigonal structure of ZHF and surface area is 43.08 m2/g. Cs+ removal was dependent on pH, with the greatest adsorption occurring under near-neutral conditions, and the removal process decreased with increasing pH. The Langmuir model was determined to be suitable for describing the adsorption process of Cs+ by ZHF. The mechanism of Cs+ adsorption was examined by Total Reflection X-ray Fluorescence (TXRF) using the gallium internal standard. In addition, the main mechanism of Cs+ adsorption by the ion exchange process was proposed and discussed.
  • Publication
    Norquandrangularic acid D, a new trinorcycloartane isolated from the leaves of Combretum quadrangulare
    ( 2021)
    Huu-Hung Nguyen
    ;
    Xuan-Hao Bui
    ;
    Thi-Minh-Dinh Tran
    ;
    Jirapast Sichaem
    ;
    Thi-Kim-Dung Le
    ;
    Ngoc-Hong Nguyen
    ;
    Thuc-Huy Duong
    Phytochemical investigation on the leaves of Combretum quadrangulare growing in Vietnam afforded a new trinorcycloartane triterpenoid, norquandrangularic acid D (1), along with three known compounds, betulinic acid (2), luteolin (3), and apigenin (4). Their structures were elucidated using spectroscopic methods and comparison was made with reports in the literature. Compounds 1 and 3 were evaluated for α-glucosidase inhibition. Compound 3 showed significant activity, with an IC50 value of 11.39 µM, (acarbose, used as a positive control, had an IC50 of 367 µM).
  • Publication
    Development of polyvinyl (alcohol)/D-glucose/agar/silver nanoparticles nanocomposite film as potential food packaging material
    ( 2021)
    Bao-Tran Tran Pham
    ;
    Thuy-Hang Thi Duong
    ;
    Thuong Thi Nguyen
    ;
    Dai Van Nguyen
    ;
    Chinh Dung Trinh
    ;
    Long Giang Bach
    The functional nanocomposite films from polyvinyl (alcohol) (PVA), D-glucose, agar, and silver nanoparticles (AgNPs) components were synthesized through the facile casting method. Results from the evaluation of antimicrobial activity and composite film properties showed that the combination of PVA/D-glucose/agar with AgNPs significantly enhanced bactericidal activity against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, as well as mechanical property. Furthermore, the coating from the combination of PVA/D-glucose/agar with AgNPs was also applied in Areca banana preservation for 7 days at 25 ℃. Appearance, physiological weight loss, total soluble sugars, and titratable acidity were daily evaluated during storage period. The obtained results of this study show the promising potential of PVA/D-glucose/agar nanocomposite film incorporated with AgNPs for food packaging applications in the near future.
  • Publication
    TiO2/Ti3C2/g-C3N4 ternary heterojunction for photocatalytic hydrogen evolution
    ( 2021)
    Vu Quang Hieu
    ;
    Truong Chi Lam
    ;
    Afrasyab Khan
    ;
    Thu-Thao Thi Vo
    ;
    Thanh-Quang Nguyen
    ;
    Van Dat Doan
    ;
    Dai Lam Tran
    ;
    Van Thuan Le
    ;
    Vy Anh Tran
    Photocatalytic hydrogen (H2) generation derived by water has been considered as a renewable energy to solve environmental problems and global energy crises. Thus, it is necessary to explore the most effective photocatalysts by using multi-cocatalysts, due to an intimate interaction between different components. Therefore, we already synthesized the TiO2/Ti3C2/g-C3N4 (TTC) photocatalyst from g-C3N4 and Ti3C2 MXene via a calcination technique, and applied this composite for H2 evolution. By making use of titanium atom from Ti3C2 MXene, titanium dioxide (TiO2) was in-body developed, which leads to form a close heterostructure between metallic material and semiconductors. Besides, g-C3N4 amorphous with highly surface area also contributes to harvest light irradiation during photocatalytic activity. The optimized TTC-450 heterostructure showed a super H2 generation efficiency than those of pure g-C3N4 and other samples. Besides, TTC-450 sample also exhibited great recyclability after 4 runs. The proposed mechanism illustrates the efficient movement of generated electrons in TTC system, which leads to high H2 evolution efficiency. Moreover, the obtained results consistently emphasize the TiO2/Ti3C2/g-C3N4 composite would be a unique material for H2 production and broaden applications of MXene materials.
  • Publication
    Chemical Constituents of Cordyceps neovolkiana DL0004
    ( 2021)
    Chi-Dung Nguyen
    ;
    Thi-My-Ninh Pham
    ;
    Thi-Bich-Hang Ha
    ;
    Thi-Phuong Nguyen
    ;
    Huu-Hung Nguyen
    ;
    Hoang-Vinh-Truong Phan
    ;
    Thuc-Huy Duong
    ;
    Minh-Hiep Dinh
  • Publication
    Health risk assessment of volatile organic compounds at daycare facilities
    ( 2021)
    Mohamed Bayati
    ;
    Danh C. Vu
    ;
    Phuc H. Vo
    ;
    Elizabeth Rogers
    ;
    Jihyun Park
    ;
    Thi L. Ho
    ;
    Alexandra N. Davis
    ;
    Zehra Gulseven
    ;
    Gustavo Carlo
    ;
    Francisco Palermo
    ;
    Jane A. McElroy
    ;
    Susan C. Nagel
    ;
    Chung‐Ho Lin
    Children are particularly vulnerable to many classes of the volatile organic compounds (VOCs) detected in indoor environments. The negative health impacts associated with chronic and acute exposures of the VOCs might lead to health issues such as genetic damage, cancer, and disorder of nervous systems. In this study, 40 VOCs including aldehydes and ketones, aliphatic hydrocarbons, esters, aromatic hydrocarbons, cyclic terpenes, alcohols, and glycol ethers were identified and qualified in different locations at the University of Missouri (MU) Child Development Laboratory (CDL) in Columbia, Missouri. Our results suggested that the concentrations of the VOCs varied significantly among classrooms, hallways, and playground. The VOCs emitted from personal care and cleaning products had the highest indoor levels (2-ethylhexanol-1, 3-carene, homomenthyl salicylate with mean concentration of 5.15 µg/m3, 1.57 µg/m3, and 1.47 µg/m3, respectively). A cancer risk assessment was conducted, and none of the 95th percentile dose estimates exceeded the age-specific no significant risk levels (NSRL) in all classrooms. Dimensionless toxicity index scores were calculated for all VOCs using a novel web-based framework called Toxicological Prioritization Index (ToxPi), which integrates multiple sources of toxicity data. According to the method, homomenthyl salicylate, benzothiazole, 2-ethylhexyl salicylate, hexadecane, and tridecane exhibited diverse toxicity profiles and ranked as the five most toxic indoor VOCs. The findings of this study provide critical information for policy makers and early education professionals to mitigate the potentially negative health impacts of indoor VOCs in the childcare facilities.
  • Publication
    Nghiên cứu tổng hợp vật liệu oxit hỗn hợp sắt mangan trên nền diatomite Phú Yên và khả năng ứng dụng làm chất hấp phụ loại bỏ Asen trong môi trường nước
    ( 2021)
    Nguyễn Thị Thanh Tú
    The paper presents the modification of Phu Yen diatomite by oxidationreduction reaction between Fe (II) and KMnO4 salts in solution pH = 6 on the diatomite surface. Characteristics of modified materials and the influence of research factors on these characteristics were investigated using techniques XRD, EDX, XPS, SEM, TEM, BET. Arsenic adsorption capacity of modified materials, the influence of environmental factors on the adsorption capacity were also investigated and evaluated. The results showed that mixed oxide-modified diatomite has higher arsenic adsorption capacity than natural diatomite and modified diatomite by individual oxides.
  • Publication
    p-Coumaric Acid Enhances Hypothalamic Leptin Signaling and Glucose Homeostasis in Mice via Differential Effects on AMPK Activation
    ( 2021)
    Linh V. Nguyen
    ;
    Khoa D. A. Nguyen
    ;
    Chi-Thanh Ma
    ;
    Quoc-Thai Nguyen
    ;
    Huong T. H. Nguyen
    ;
    Dong-Joo Yang
    ;
    Trung Le Tran
    ;
    Ki Woo Kim
    ;
    Khanh V. Doan
    AMP-activated protein kinase (AMPK) plays a crucial role in the regulation of energy homeostasis in both peripheral metabolic organs and the central nervous system. Recent studies indicated that p-Coumaric acid (CA), a hydroxycinnamic phenolic acid, potentially activated the peripheral AMPK pathway to exert beneficial effects on glucose metabolism in vitro. However, CA’s actions on central AMPK activity and whole-body glucose homeostasis have not yet been investigated. Here, we reported that CA exhibited different effects on peripheral and central AMPK activation both in vitro and in vivo. Specifically, while CA treatment promoted hepatic AMPK activation, it showed an inhibitory effect on hypothalamic AMPK activity possibly by activating the S6 kinase. Furthermore, CA treatment enhanced hypothalamic leptin sensitivity, resulting in increased proopiomelanocortin (POMC) expression, decreased agouti-related peptide (AgRP) expression, and reduced daily food intake. Overall, CA treatment improved blood glucose control, glucose tolerance, and insulin sensitivity. Together, these results suggested that CA treatment enhanced hypothalamic leptin signaling and whole-body glucose homeostasis, possibly via its differential effects on AMPK activation.
  • Publication
    Isolation and Plant Growth Promoting Characterization of Potassium Solubilizing Bacteria in Rhizosphere of Some Crops in Vietnam
    ( 2021)
    Võ Thị Xuyến
    Many soil microorganisms are able to dissolvethese types of potassium and have been applied in agriculture. These potassium solubilizing bacteria (KSB) have also been shown to have by many other direct or indirect plant growth-promoting activities. This study's aim was isolation, screening and plant growth-promoting characterization of KSB from rhizospheric soil of some crops in Vietnam. The results were that thirty-four KSB isolates were collected on Aleksandrov agar medium from ten soil samples from the rhizospheres of banana, pitaya, and mango. By the spot streak technique on this medium, three KSB isolates including BE204, BE208 and BE220 were screened with the potassium solubility indexes 10.87, 10.97, and 10.72, respectively. All of three selected isolates were identified as belong to Burkholderia genus by the specific protein springers, in which, BE208 had the best match with B. gladiola. The two strains BE204 and BE208 showed a higher potential because of the capility to antagonize to most of thirteen surveyed phytopathogens including Phomopsis longicolla, Neoscytalidium dimidiatum, and Phyllosticta cavendishii, based on the dual culture technique, causing significant damage on many crops in Vietnam. In addition, the two strains were also able to dissolve phosphate and zinc and produce enzymes hydrolyzing protein, starch and cellulose by also the spot streak technique. The results contributed the potential bacterial collection for the research and development of products from indigenous KSB in Vietnam. However, additional classifications as well as the safety of these selected strains need to be further investigated.
  • Publication
    Electrochemical Determination of Diclofenac by Using ZIF-67/g-C3N4 Modified Electrode
    ( 2021)
    Dang Thi Ngoc Hoa
    ;
    Nguyen Thi Thanh Tu
    ;
    Le Van Thanh Son
    ;
    Le Vu Truong Son
    ;
    Tran Thanh Tam Toan
    ;
    Pham Le Minh Thong
    ;
    Dao Ngoc Nhiem
    ;
    Pham Khac Lieu
    ;
    Dinh Quang Khieu
    ;
    Thanh Son Le
    A facial differential pulse voltammetric procedure using a glassy carbon electrode modified with zeolite imidazolate framework-67/graphitic carbon nitride (ZIF-67/g-C3N4) for the diclofenac (DCF) determination is demonstrated. ZIF-67/g-C3N4 with different mass ratios of the components was synthesized in a self-assembly process. The obtained materials were characterized by using X-ray diffraction, scanning electron microscopy (SEM), EDX-mapping, and nitrogen adsorption/desorption isotherms. The peak current varies linearly with the DCF concentration in the range of 0.2–2.2 μmol·L−1 and has a detection limit of 0.071 μmol·L−1. The modified electrode exhibits acceptable repeatability, reproducibility, and selectivity towards DCF. The proposed electrode allows determining DCF in human urine without pretreatment, and the results are comparable with those determined with HPLC.