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"Nguyen Thi, Oanh"
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Integrated emission inventory and modeling to assess distribution of particulate matter mass and black carbon composition in Southeast Asia
by
Permadi, Didin Agustian
,
Kim Oanh, Nguyen Thi
,
Vautard, Robert
in
Aerosol optical depth
,
Aerosols
,
Air monitoring
2018
This is part of a research study addressing the potential co-benefits associated with selected black carbon (BC) emission reduction measures on mitigation of air pollution and climate forcing in Southeast Asia (SEA). This paper presents details of emission inventory (EI) results and WRF–CHIMERE model performance evaluation. The SEA regional emissions for 2007 were updated with our EI results for Indonesia, Thailand, and Cambodia and used for the model input. WRF–CHIMERE-simulated 2007 PM10, PM2.5, and BC over the SEA domain (0.25° × 0.25°) and the results were evaluated against the available meteorology and air quality monitoring data in the domain. WRF hourly simulation results were evaluated using the observed data at eight international airport stations in five SEA countries and showed a satisfactory performance. WRF–CHIMERE results for PM10 and PM2.5 showed strong seasonal influence of biomass open burning while the BC distribution showed the influence of urban activities in big SEA cities. Daily average PM10 constructed from the hourly concentrations were obtained from the automatic monitoring stations in three large SEA cities, i.e., Bangkok, Kuala Lumpur, and Surabaya, for model evaluation. The daily observed PM2.5 and BC concentrations obtained from the Improving Air Quality in Asian Developing Countries (AIRPET) project for four cities (i.e., Bangkok, Hanoi, Bandung, and Manila) were also used for model evaluation. In addition, hourly BC concentrations were taken from the measurement results of the Asian Pacific Network (APN) project at a suburban site in Bangkok. The modeled PM10 and BC satisfactorily met all suggested statistical criteria for PM evaluation. The modeled PM2.5∕PM10 ratios estimated for four AIRPET sites ranged between 0.47 and 0.59, lower than observed values of 0.6–0.83. Better agreement was found for BC∕PM2.5 ratios with the modeled values of 0.05–0.33 as compared to the observation values of 0.05–0.28. AODEM (extended aerosol optical depth module) was used to calculate the total columnar aerosol optical depth (AOD) and BC AOD up to the top of the domain at 500 hPa (∼ 5500 m), which did not include the free-tropospheric long-range transport of the pollution. The model AOD results calculated using the internal mixing assumption were evaluated against the observed AOD by both AERONET and MODIS satellite in 10 countries in the domain. Our model results showed that the BC AOD contributed 7.5–12 % of the total AOD, which was in the same range reported by other studies for places with intensive emissions. The results of this paper are used to calculate the regional aerosol direct radiative forcing under different emission reduction scenarios to explore potential co-benefits for air quality improvement, reduction in the number of premature deaths, and climate forcing mitigation in SEA in 2030 (Permadi et al., 2017a).
Journal Article
Application of Methylopila sp. DKT for Bensulfuron-methyl Degradation and Peanut Growth Promotion
2020
Bensulfuron-methyl is an herbicide widely used for weed control although its residues cause damage to other crops during crop rotations. In this study, the biodegrading activity of bensulfuron-methyl by a plant growth-promoting bacterial strain was carried out. Methylopila sp. DKT isolated from soil was determined for bensulfuron-methyl degradation and phosphate solubilization in the liquid media and soil. Moreover, the effects of the herbicide on peanut development and the role of Methylopila sp. DKT on the growth promotion of peanut were investigated. The results showed that the isolate effectively utilized the compound as a sole carbon source and solubilized low soluble inorganic phosphates. Methylopila sp. DKT also utilized 2-amino-4,6-dimethoxypyrimidine, a metabolite of bensulfuron-methyl degradation, as a sole carbon and energy source, and released ammonium and nitrate. The supplementation with Methylopila sp. DKT in soil increased the peanut biomass and the phosphorus content in the plant. In addition, the inoculation with Methylopila sp. DKT in soil and peanut cultivation increased the bensulfuron-methyl degradation by 57.7% for 1 month, which suggests that both plants and the bacterial isolate play a key role in herbicide degradation. These results indicate that the studied strain has a high potential for soil remediation and peanut growth promotion.
Journal Article
Assessment of emission scenarios for 2030 and impacts of black carbon emission reduction measures on air quality and radiative forcing in Southeast Asia
by
Permadi, Didin Agustian
,
Kim Oanh, Nguyen Thi
,
Vautard, Robert
in
2030 AD
,
Aerosol optical depth
,
Aerosols
2018
Our previously published paper (Permadi et al. 2018) focused on the preparation of emission input data and evaluation of WRF–CHIMERE performance in 2007. This paper details the impact assessment of the future (2030) black carbon (BC) emission reduction measures for Southeast Asia (SEA) countries on air quality, health and BC direct radiative forcing (DRF). The business as usual (BAU2030) projected emissions from the base year of 2007 (BY2007), assuming “no intervention” with the linear projection of the emissions based on the past activity data for Indonesia and Thailand and the sectoral GDP growth for other countries. The RED2030 featured measures to cut down emissions in major four source sectors in Indonesia and Thailand (road transport, residential cooking, industry, biomass open burning) while for other countries the Representative Concentration Pathway 8.5 (RCP8.5) emissions were assumed. WRF–CHIMERE simulated levels of aerosol species under BAU2030 and RED2030 for the modeling domain using the base year meteorology and 2030 boundary conditions from LMDZ-INCA. The extended aerosol optical depth module (AODEM) calculated the total columnar AOD and BC AOD for all scenarios with an assumption on the internal mixing state. Under RED2030, the health benefits were analyzed in terms of the number of avoided premature deaths associated with ambient PM2.5 reduction along with BC DRF reduction. Under BAU2030, the average number of the premature deaths per 100 000 people in the SEA domain would increase by 30 from BY2007 while under RED2030 the premature deaths would be cut down (avoided) by 63 from RED2030. In 2007, the maximum annual average BC DRF in the SEA countries was 0.98 W m−2, which would increase to 2.0 W m−2 under BAU2030 and 1.4 W m−2 under RED2030. Substantial impacts on human health and BC DRF reduction in SEA could result from the emission measures incorporated in RED2030. Future works should consider other impacts, such as for agricultural crop production, and the cost–benefit analysis of the measures' implementation to provide relevant information for policy making.
Journal Article
Anaerobic Degradation of Chloroanilines by Geobacter sp. KT5
2019
A chloroaniline-degrading bacterial strain isolated from polluted sediment in the Mekong River was identified as Geobacter sp. KT5. The obtained isolate was found to utilize a wide range of trichloroanilines (TCAs), dichloroanilines (DCAs), monochloroanilines (MACs), and aniline as sources of carbon and energy. It also used Fe(III) as a terminal electron acceptor under anaerobic conditions. Among the chlorinated anilines, KT5 utilized 2,3,4-trichloroaniline (234TCA) with the highest rate (2.48 ± 0.32 µM day−1). On determining the degradation pathway for chloroanilines (CAs) in Geobacter sp. KT5, it showed that the removal of ortho and para halogen was dominant. Firstly, KT5 ortho-dechlorinated some TCAs to DCAs, and then reductively transformed them into MACs and aniline prior to complete degradation with the iron reduction stoichiometry and release of nitrogen and chlorine. The KT5 augmentation in sediment slurry enhanced the degradation of CAs and aniline; however, the anaerobic degradation rates in slurry were significantly lower compared to those in liquid media.
Journal Article
Enhanced Degradation of Rhodamine B by Metallic Organic Frameworks Based on NH2-MIL-125(Ti) under Visible Light
2021
Samples of the bimetallic-based NH2-MIL-125(Ti) at a ratio of Mn+/Ti4+ is 0.15 (Mn+: Ni2+, Co2+ and Fe3+) were first synthesized using the solvothermal method. Their fundamental properties were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectra, scanning electron microscopy (SEM), N2 adsorption–desorption measurements, and UV–Vis diffuse reflectance spectroscopy (UV-Vis DRS). The as-acquired materials were used as high-efficiency heterogeneous photocatalysts to remove Rhodamine B (RhB) dye under visible light. The results verified that 82.4% of the RhB (3 × 10−5 M) was degraded within 120 min by 15% Fe/Ti−MOFs. Furthermore, in the purpose of degrading Rhodamine B (RhB), the rate constant for the 15% Fe/Ti-MOFs was found to be 2.6 times as fast as that of NH2-MIL-125(Ti). Moreover, the 15% Fe/Ti-MOFs photocatalysts remained stable after three consecutive cycles. The trapping test demonstrated that the major active species in the degradation of the RhB process were hydroxyl radicals (HO∙) and holes (h+).
Journal Article
Degradation of Diuron by a Bacterial Mixture and Shifts in the Bacterial Community During Bioremediation of Contaminated Soil
by
Thanh Le Uyen
,
Tuong Tran Duc
,
Duc Ha Danh
in
Acinetobacter baumannii
,
Bacillus subtilis
,
Bacteria
2022
Diuron, a phenylurea herbicide, has been extensively applied in controlling a wide range of weeds in several crops. In the current study, a mixed culture of three bacterial strains, i.e., Bacillus subtilis DU1, Acinetobacter baumannii DU, and Pseudomonas sp. DUK, isolated from sugarcane soil, completely degraded diuron and 3,4-DCA in liquid media at 20 mg L−1 within 48 h. During diuron degradation, a few metabolites (DCPMU, DCPU, and 3,4-DCA) were produced. Further determination of ring-cleavage pathways demonstrated that Acinetobacter baumannii DU and Pseudomonas fluorescens DUK degraded diuron and 3,4-DCA via ortho-cleavage. In contrast, Bacillus subtilis DU transformed these compounds via meta-cleavage pathways. Moreover, diuron caused a significant shift in the bacterial community in soil without diuron history. The augmentation of mountain soil with the isolated bacteria resulted in nearly three times higher degradation rate of diuron than the degradation by indigenous microorganisms. This study provides important information on in situ diuron bioremediation from contaminated sites by bioaugmentation with a mixed bacterial culture.
Journal Article
Genetic and metabolic analysis of the carbofuran catabolic pathway in Novosphingobium sp. KN65.2
by
Fida, Tekle Tafese
,
Bers, Karolien
,
Nguyen, Thi Phi Oanh
in
Analysis
,
Applied Genetics and Molecular Biotechnology
,
Bacteria
2014
The widespread agricultural application of carbofuran and concomitant contamination of surface and ground waters has raised health concerns due to the reported toxic effects of this insecticide and its degradation products. Most bacteria that degrade carbofuran only perform partial degradation involving carbamate hydrolysis without breakdown of the resulting phenolic metabolite. The capacity to mineralize carbofuran beyond the benzofuran ring has been reported for some bacterial strains, especially sphingomonads, and some common metabolites, including carbofuran phenol, were identified. In the current study, the catabolism of carbofuran by Novosphingobium sp. KN65.2 (LMG 28221), a strain isolated from a carbofuran-exposed Vietnamese soil and utilizing the compound as a sole carbon and nitrogen source, was studied. Several KN65.2 plasposon mutants with diminished or abolished capacity to degrade and mineralize carbofuran were generated and characterized. Metabolic profiling of representative mutants revealed new metabolic intermediates, in addition to the initial hydrolysis product carbofuran phenol. The promiscuous carbofuran-hydrolyzing enzyme Mcd, which is present in several bacteria lacking carbofuran ring mineralization capacity, is not encoded by the Novosphingobium sp. KN65.2 genome. An alternative hydrolase gene required for this step was not identified, but the constitutively expressed genes of the unique cfd operon, including the oxygenase genes cfdC and cfdE, could be linked to further degradation of the phenolic metabolite. A third involved oxygenase gene, cfdI, and the transporter gene cftA, encoding a TonB-dependent outer membrane receptor with potential regulatory function, are located outside the cfd cluster. This study has revealed the first dedicated carbofuran catabolic genes and provides insight in the early steps of benzofuran ring degradation.
Journal Article
Excellent survival benefit achieved in patients with advanced-stage non-small cell lung cancer harboring the epidermal growth factor receptor-G719X mutation treated by afatinib: the real-world data from a multicenter study in Vietnam
by
Nguyen, Dac Nhan Tam
,
Truong, Cong Minh
,
Nguyen, Hoang Gia
in
Adult
,
Afatinib - adverse effects
,
Afatinib - therapeutic use
2025
Background:
Afatinib is indicated for patients with advanced-stage non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations, including uncommon mutations. However, the differences in survival benefits between patients with different types of EGFR mutations remain unclear.
Objectives:
This study aimed to compare the effectiveness of afatinib treatment in patients harboring the EGFR-G719X mutation with that in patients carrying other uncommon EGFR mutations.
Design:
This was a retrospective study.
Methods:
Ninety-two patients with locally advanced and metastatic NSCLC, of whom 49 patients with EGFR-G719X mutations that were both single and compound, and 43 patients harbored other uncommon EGFR mutations, who were treated with afatinib as first-line treatment. The patients were followed up and evaluated every 3 months or when there were symptoms of progressive disease. The endpoints were the objective response rate (ORR), time-to-treatment failure (TTF), and overall survival (OS).
Results:
The average ages of patients with the EGFR-G719X and uncommon EGFR mutations were 62.7 years and 63.1 years, respectively. There were no significant differences in sex or smoking history between the two groups. In total, 28.6% of patients with the G719X mutation and 23.3% of patients with other mutations had brain metastases. The ORR of patients with the G719X mutation was 79.6%, which was 10% higher than that of patients with other EGFR mutations. Patients harboring the EGFR-G719X mutation had median TTF and median OS periods of 19.3 months and 31.4 months, respectively, which were significantly higher than those of patients carrying other mutations at 11.2 months. Subgroup analysis showed that TTF and OS benefits were observed in female patients, patients without brain metastasis, and patients with good performance status who harbored the G719X mutation.
Conclusion:
Patients with the EGFR-G719X mutation achieve significantly better TTF and OS benefits than those with other uncommon EGFR mutations.
Journal Article
A Survey-Based Emission Inventory of Greenhouse Gases Released from Rice Production on Consolidated Land in the Red River Delta of Vietnam
by
Oanh, Nguyen Thi Kim
,
Yen, Nguyen Thi Bich
,
Hai Van, Dinh Thi
in
Agriculture
,
Carbon dioxide
,
Carbon dioxide emissions
2025
In this study, relevant rice cultivation data were collected through a local survey, and the life cycle assessment (LCA) method was employed to quantify greenhouse gas (GHG) emissions from rice production on consolidated land in the Red River Delta (RRD). Systematic sampling was used in face-to-face interviews with 45 rice farming households in a representative commune of Hai Duong province. Specific GHG emissions were significantly higher in the summer crop (averaged at 11.4 t CO2-eq/ha or 2.2 t CO2-eq/t grain) than in the spring crop (6.8 t CO2-eq/ha or 1.2 t CO2-eq/t grain). Methane was a dominant GHG emitted from paddy fields, contributing 84% of the total emissions of CO2-eq in the summer crop and 73% in the spring crop. Fertilizer use and N2O emissions accounted for 9% of emissions in the summer crop and 16% in the spring crop. Energy consumption for machinery and irrigation added a further 4% and 8%, respectively. Annually, as of 2023, the rice production activities in the RRD release 7.3 Tg of CO2-eq (100 years), a significant contribution to the national GHG emissions. GHG emissions under alternative scenarios of rice straw management were assessed. This study highlights the role of land consolidation in improving water management, which contributes to lowering emissions. Based on the findings, several mitigation measures could be identified, including improved irrigation practices, optimized fertilizer use, and the promotion of sustainable rice straw management practices.
Journal Article
Real-world analysis of afatinib as a first-line treatment for patients with advanced stage non-small-cell lung cancer with uncommon EGFR mutations: a multicenter study in Vietnam
by
Thu Hoang, Thi Anh
,
Truong, Cong Minh
,
Nguyen, Hoang Gia
in
Brain cancer
,
Diarrhea
,
Epidermal growth factor receptors
2024
Background:
Afatinib is indicated for advanced-stage non-small-cell lung cancer (NSCLC) with Epidermal Growth Factor Receptor (EGFR) and uncommon mutations. However, real-world studies on this topic are limited. This study aimed to evaluate afatinib as first-line therapy for locally advanced and metastatic NSCLC with uncommon EGFR mutations.
Patients and methods:
A retrospective study included 92 patients with advanced NSCLC with uncommon and compound EGFR mutations, treated with afatinib as first-line therapy. Patients were followed up and evaluated every 3 months or when symptoms of progressive disease arose. The endpoints were objective response rate (ORR), time-to-treatment failure (TTF), and adverse events.
Results:
The G719X EGFR mutation had the highest occurrence rate (53.3% for both monotherapy and the compound). By contrast, the compound mutation G719X–S768I was observed at a rate of 22.8%. The ORR was 75%, with 15.2% of patients achieving complete response. The overall median TTF was 13.8 months. Patients with the G719X EGFR mutation (single and compound) had a median TTF of 19.3 months, longer than that of patients with other mutations, who had a median TTF of 11.2 months. Patients with compound EGFR mutations (G719X and S768I) demonstrated a median TTF of 23.2 months compared to that of 12.3 months for other mutations. Tolerated doses of 20 or 30 mg achieved a longer median TTF of 17.1 months compared to 11.2 months with 40 mg. Median TTF differed between patients with and without brain metastasis, at 11.2 and 16.9 months, respectively. Rash (55.4%) and diarrhea (53.3%) were the most common adverse events, primarily grades 1 and 2. Other side effects occurred at a low rate.
Conclusion:
Afatinib is effective for locally advanced metastatic NSCLC with uncommon EGFR mutations. Patients with G719X, compound G719X–S768I mutations, and tolerated doses of 20 or 30 mg had a longer median TTF than those with other mutations.
Journal Article