Visible light-driven photocatalytic degradation of doxycycline using ZnO/g-C₃N₄/biochar composite in aqueous solution

Nguyen Van Hung,Bui Thi Minh Nguyet,Nguyen Huu Nghi,Nguyen Minh Luon,Nguyen Ngoc Bich,Le Van Thanh Son,Nguyen Trung Kien,Dao Ngoc Nhiem,Nguyen Thanh Tuoi,Dinh Quang Khieu 대한환경공학회 2024 Environmental Engineering Research Vol.29 No.4

In the present work, ZnO/g-C₃N₄/biochar was prepared, and it was used for visible-light driven photocatalytic degradation of some colorants (methylene blue, rhodamine B, methyl orange) and some antibiotics (doxycycline, ciprofloxacin, amoxicilline). Biochar was prepared by pyrolysing Phragmites australis biomass. The ZnO/g-C₃N₄/biochar composite was synthesized with the alkaline hydrolysis method. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy, transition electron microscopy, energy dispersive X-ray/elemental mapping, ultraviolet-visible-diffuse reflectance spectroscopy, photoluminescence spectroscopy, nitrogen adsorption/desorption isotherms and X-ray photoelectron spectroscopy. The results show that ZnO nanoparticles with a large surface area are highly dispersed on the g-C₃N₄ particle surface and biochar. The composite exhibits superior photocatalytic degradation ability toward doxycycline, a broad-spectrum antibiotic of the tetracycline compared with individual components (ZnO or g-C₃N₄) and satisfies stability after six treatment cycles. The kinetics and degradation mechanisms of doxycyline were also addressed. In addition, the present catalyst also exhibits the photocatalytic degradation of methylene blue, rhodamine B, methyl orange, ciprofloxacin and amoxicillin in visible-light regions.

Analytical Asymptotic Expressions for the Green’s Function of the Electron in a Single-Level Quantum Dot at the Kondo and the Fano Resonances

Nguyen Van Hieu,Nguyen Bich Ha,V. P. Gerdt,O. Chuluunbaatar,A. A. Gusev,Yu. G. Palii,Nguyen Van Hop 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.6

The Kondo and the Fano resonances in the two-point Green’s function of the single-level quantum dot were found and investigated in many previous works by means of different numerical calculation methods. In this report, we present a derivation of the analytical forms of the resonance terms in the expression of the two-point Green’s function. For that purpose, the system of Dyson equations for the two-point nonequilibrium Green’s functions in the complex-time Keldysh formalism was established to the second order in the tunneling coupling constants with the mean field approximation for the statistical averages of the products of four electron creation and destruction operators. This system of Dyson equations was solved exactly by means of the computer algebra and the analytical expressions for the resonance terms are derived. The conditions for the existence of the Kondo or the Fano resonances were found.

Environmental Factors Affecting the Abundance and Presence of Tree Species in a Tropical Lowland Limestone and Non-limestone Forest in Ben En National Park, Vietnam

Nguyen, Thinh Van,Mitlohner, Ralph,Bich, Nguyen Van,Do, Tran Van Institute of Forest Science 2015 Journal of Forest Science Vol.31 No.3

The effect of environmental variables on the presence and abundance of tree species in a tropical lowland undisturbed limestone and non-limestone forest in Ben En National Park, Vietnam was investigated. The relationships between 13 environmental variables and 29 tree species with a DBH ${\geq}10cm$, as well as between six 6 physical variables with 26 species of seedling and sapling communities were assessed by canonical correspondence analysis (CCA). Data concerning all tree species ${\geq}10cm$ DBH were collected from eighteen $400m^2$ sample plots, while the abundance of regeneration (all individuals ${\leq}5cm$ DBH) was counted in fifty $2{\times}20m$ strip-plots. The significance of species-environments correlations were tested by distribution-free Monte Carlo tests. The CCA of the 29 examined tree species and 13 environmental variables indicated that the presence and abundance of the tree species were closely related to topographic factors. We may confirm that soil properties including pH, soil moisture content, and soil textures, were the most crucial factor in tree species composition and their distribution. Several species including Pometia pinnata, Amesiodendron chinense, Gironniera cuspidate, Cinnamomum mairei, and Caryodaphnopsis tonkinensis were not controlled by soil properties and topographic variables. The CCA also indicated that the abundance of regeneration tree species at all sites had positive and significant correlations with soil depth, while the occurrence of several other tree species (such as Koilodepas longifolium and Aglaia dasyclada) was positively correlated with a higher slope and rocky outcrop.

A New Ceanothane-Type Triterpenoid Saponin Isolated from Gouania leptostachya DC. var. tonkinensis Pit. and Its Underlying Anti-Inflammatory Effects

( Nguyen Thi Hang ),( Nguyen Thi Bich Thu ),( Le Ba Vinh ),( Nguyen Viet Phong ),( Tran Van On ),( Ki Yong Lee ) 한국미생물생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.7

Metabolites from medicinal plants continue to hold significant value in the exploration and advancement of novel pharmaceuticals. In the search for plants containing compounds with anti-inflammatory effects, we observed that the ethanol (EtOH) extract obtained from the aerial components of Gouania leptostachya DC. var. tonkinensis Pit. exhibited substantial suppression of nitric oxide (NO) in vitro. In a phytochemical study on an EtOH extract of G. leptostachya, 11 compounds were purified, including one unreported compound namely gouanioside A (1). Their chemical structures were unambiguously determined through the use of various spectroscopic techniques, such as 1 and 2D NMR, IR, and HR-ESI-MS, and by producing derivatives via chemical reactions. The EtOH extract, fractions, and a new compound exerted inflammatory effects by altering NO synthesis in murine RAW264.7 macrophage cells stimulated with lipopolysaccharide. The underlying inflammatory mechanism of the new compound 1 was also explored through various in vitro experiments. The results of this study indicate the potential usefulness of new compound 1 from G. leptostachya as a treatment for inflammatory diseases.

Theoretical Description of the Manipulation of a Double Quantum Dot as a Charge Qubit

Nguyen Van Hieu,Nguyen Bich Ha 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.3

The charge qubit operation on an isolated double quantum dot, i.e., the manipulation of electron charge distribution and charge curent in an isolated double quantum dot by changing the bias voltage applied to the gates of two quantum dots was performed in recent experimental works towardsthe use ofthis charge qubitin quantum informationprocesing. Inthis work, we present the theory of charge qubit operation of this kind on an isolated double quantum dot consisting of two single-level quantum dots connected one with an other by means of electron tunneling through a potential barier and containing only one electron. The system of rate equations for matrix elements of density matrix of electron system was derived. The formulae determining the time dependence of the charge distribution in the double quantum dot due to abrupt changes in the bias voltage applied to the gates of two quantum dots during the manipulation process were established. The comparison with experimental data was caried out for the special case of decoherence due to the interaction of electron with environment.

Seroprevalence of Tissue and Luminal Helminths among Patients in Hanoi Medical University Hospital, Vietnam, 2018

Nguyen Van De,Pham Ngoc Minh,Nguyen Ngoc Bich,채종일 대한기생충학ㆍ열대의학회 2020 The Korean Journal of Parasitology Vol.58 No.4

A serological survey was performed using ELISA to estimate the prevalence of tissue and luminal helminthic infections among hospital patients in Hanoi region, Vietnam. An overall seroprevalence of tissue and luminal helminthiases was 64.0% (95% CI 61.2–66.8) among 1,120 patients who visited Hanoi Medical University Hospital, Vietnam in 2018. The highest seroprevalence was observed against Toxocara spp. (59.0%), followed by Strongyloides stercoralis (46.3%), Gnathostoma spp. (25.5%), cysticercus (12.8%), Angiostrongylus cantonensis (10.5%), Fasciola spp. (11.1%), and Clonorchis sinensis (8.7%). Mono-infection by one species (11.1%) was lower than multiple infections (53.0%) (P<0.05). The seroprevalence in males (59.3%) was lower than in females (66.2%) but not statistically significant (P>0.05). Children (<15 years) revealed lower seroprevalence (34.0%) than adults (68.4%), and the age group 51–70 years revealed the highest seroprevalence (76.0%). Among the seropositive patients, eosinophilia (≥8.0%) was noted in 80.2%. The present results suggested active transmission of various tissue and luminal helminths among people in Hanoi, Vietnam.

Mesenchymal Stem Cell Transplantation for Ischemic Diseases: Mechanisms and Challenges

Van Nguyen Thi-Tuong,Vu Ngoc Bich,Van Pham Phuc 한국조직공학과 재생의학회 2021 조직공학과 재생의학 Vol.18 No.4

Ischemic diseases are conditions associated with the restriction or blockage of blood supply to specific tissues. These conditions can cause moderate to severe complications in patients, and can lead to permanent disabilities. Since they are blood vessel-related diseases, ischemic diseases are usually treated with endothelial cells or endothelial progenitor cells that can regenerate new blood vessels. However, in recent years, mesenchymal stem cells (MSCs) have shown potent bioeffects on angiogenesis, thus playing a role in blood regeneration. Indeed, MSCs can trigger angiogenesis at ischemic sites by several mechanisms related to their trans-differentiation potential. These mechanisms include inhibition of apoptosis, stimulation of angiogenesis via angiogenic growth factors, and regulation of immune responses, as well as regulation of scarring to suppress blood vessel regeneration when needed. However, preclinical and clinical trials of MSC transplantation in ischemic diseases have shown some limitations in terms of treatment efficacy. Such studies have emphasized the current challenges of MSC-based therapies. Treatment efficacy could be enhanced if the limitations were better understood and potentially resolved. This review will summarize some of the strategies by which MSCs have been utilized for ischemic disease treatment, and will highlight some challenges of those applications as well as suggesting some strategies to improve treatment efficacy.

Two Human Cases of Echinococcus ortleppi Infection in the Lung and Heart in Vietnam

Nguyen Van De,Pham Ngoc Minh,Le Van Duyet,Nguyen Ngoc Bich,Trinh Nam Son,정봉광,채종일 대한기생충학ㆍ열대의학회 2020 The Korean Journal of Parasitology Vol.58 No.4

This is a report of 2 cases of human hydatidosis caused by Echinococcus ortleppi in Vietnam. The patients were a 12-year-old male (case 1) having a cyst of 10.0×9.0 cm size in the lung and a 50-year-old female with a 3.0×3.3 cm-sized cyst in the heart. Eosinophilia was 33.7% in the male and 45.8% in the female patient. C-reactive protein was increased to 16.5 mg/L in the male and 18.2 mg/L in the female. Both patients were positive for ELISA at OD=2.5 and 3.1, respectively. Echinococcus protoscolices were collected from the cysts by amniocentesis and surgery. The protoscolices were identified as E. ortleppi by morphology and analysis of mitochondrial NADH dehydrogenase 1 (nad1) gene sequence. Both patients were cured by surgical resection of the hydatid cyst combined with albendazole medication. The E. ortleppi infection in lung is the second report, and the other in the heart is the first in Vietnam.

Distribution Status of Hybrid Types in Large Liver Flukes, Fasciola Species (Digenea: Fasciolidae), from Ruminants and Humans in Vietnam

Thi Bich Nga Nguyen,Nguyen Van De,Thi Kim Lan Nguyen,Huynh Hong Quang,Huong Thi Thanh Doan,Takeshi Agatsuma,Thanh Hoa Le 대한기생충학열대의학회 2018 The Korean Journal of Parasitology Vol.56 No.5

Antibiotic-Resistant Gram-negative Bacteria Carriage in Healthcare Workers Working in an Intensive Care Unit

Duong Bich Thuy,Duong Minh Cuong,Campbell James,Nguyen Van Minh Hoang,Nguyen Huu Hien,Bui Thi Bich Hanh,Nguyen Van Vinh Chau,McLaws Mary-Louise 대한감염학회 2021 Infection and Chemotherapy Vol.53 No.3

Little is known about antibiotic-resistant Gram-negative bacteria (GNB) intestinal carriage among healthcare workers (HCWs) in Vietnam. All HCWs at a tertiary intensive care units were asked to undertake weekly rectal swabs. Among 40 participants, 65% (26/40) carried extended spectrum β-lactamases (ESBL)/AmpC β-lactamase-producing Escherichia coli. Two HCWs colonized with ESBL/AmpC β-lactamase-producing Klebsiella pneumoniae. One HCW colonized with Acinetobacter baumannii. No one carried Pseudomonas spp.. A quarter (10/40) of HCWs were identified as persistent and frequent carriers. There is an urgent need to screen antibiotic-resistant GNB among HCWs and improve HCWs’ hand hygiene compliance to reduce the transmission of antibiotic-resistant GNB in the hospital.