| 1. |
- Nguyet, To Thi, et al.
(författare)
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Enhanced response characteristics of NO2 gas sensor based on ultrathin SnS2 nanoplates : Experimental and DFT study
- 2024
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Ingår i: Sensors and Actuators A-Physical. - : Elsevier. - 0924-4247 .- 1873-3069. ; 373
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Tidskriftsartikel (refereegranskat)abstract
- Layered-metal dichalcogenides with extraordinary characteristics of vast surface area, tunable bandgap and superior adsorption capability enable the potential for application in gas sensors. However, the synthesis of effective material for enhanced response performance remains a challenge. Herein, we exploited a fascinating sensitivity and selectivity towards NO2 gas detection using SnS2 nanoflakes prepared via the hydrothermal method. SnS2 nanoflakes with a thickness of 25 nm and an average diameter of approximately 500 nm show the potential for the detection of NO2 gas at low concentrations of ppb levels. The sensing properties of the SnS2 sensors were investigated for different concentrations of NO2 at various operating temperatures. The sensor exhibits the highest gas-sensing response of 161 at 250 οC upon exposure to 5 ppm of NO2 gas with fast response and recovery times. In addition, the sensor shows excellent selectivity with a low detection limit of ppb level. The electronic structure and gas-sensing mechanism are elucidated via finding density of states, charge density, and band structure based on DFT study which is calculated by the Vienna ab-initio simulation package (VASP). The considerable small adsorption energy reveals a physisorption of the NO2 molecules on the SnS2 surface (-0.174 eV), indicating the SnS2 nanoflakes are intriguing candidates for the speedy detection of NO2 gas.
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| 2. |
- Le, Ha V., et al.
(författare)
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MnFe 2 O 4 Nanoparticles-Catalyzed C3-Alkylation of Indoles with Benzyl Alcohols under Solvent-Free Conditions
- 2024
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Ingår i: ChemistrySelect. - 2365-6549. ; 9:33
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Tidskriftsartikel (refereegranskat)abstract
- Herein, we present an efficient, one-pot reaction for accessing 3-benzylated indoles via the coupling of benzyl alcohols with indoles under heterogeneous catalysis by manganese ferrite (MnFe2O4) nanoparticles. Notably, this reaction, for the first time, employs MnFe2O4 nanoparticles prepared using a simple grinding method. The high compatibility of MnFe2O4 nanoparticles enables a broad substrate scope and high regioselectivity. Moreover, this approach offers several attractive highlights including the use of a recyclable oxide catalyst and green and cost-effective alkylating reagents under solvent-free conditions.
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| 3. |
- Le, Ha V., et al.
(författare)
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Green Synthesis of Diphenyl-Substituted Alcohols Via Radical Coupling of Aromatic Alcohols Under Transition-Metal-Free Conditions
- 2024
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Ingår i: ChemistryOpen. - 2191-1363. ; In Press
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Tidskriftsartikel (refereegranskat)abstract
- Alcohols are common alkylating agents and starting materials alternative to harmful alkyl halides. In this study, a simple, benign and efficient pathway was developed to synthesize 1,3-diphenylpropan-1-ols via the β-alkylation of 1-phenylethanol with benzyl alcohols. Unlike conventional borrowing hydrogen processes in which alcohols were activated by transition-metal catalyzed dehydrogenation, in this work, t-BuONa was suggested to be a dual-role reagent, namely, both base and radical initiator, for the radical coupling of aromatic alcohols. The cross-coupling reaction readily proceeded under transition metal-free conditions and an inert atmosphere, affording 1,3-diphenylpropan-1-ol with an excellent yield. A good functional group tolerance in benzyl alcohols was observed, leading to the production of various phenyl-substituted propan-1-ol derivatives in moderate-to-good yields. The mechanistic studies proposed that the reaction could involve the formation of reactive radical anions by base-mediated deprotonation and single electron transfer.
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| 4. |
- Tran, Xuan-Truc Dinh, et al.
(författare)
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Integration of the Butina algorithm and ensemble learning strategies for the advancement of a pharmacophore ligand-based model : an in silico investigation of apelin agonists
- 2024
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Ingår i: Frontiers in Chemistry. - : Frontiers Media S.A.. - 2296-2646. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: 3D pharmacophore models describe the ligand's chemical interactions in their bioactive conformation. They offer a simple but sophisticated approach to decipher the chemically encoded ligand information, making them a valuable tool in drug design.Methods: Our research summarized the key studies for applying 3D pharmacophore models in virtual screening for 6,944 compounds of APJ receptor agonists. Recent advances in clustering algorithms and ensemble methods have enabled classical pharmacophore modeling to evolve into more flexible and knowledge-driven techniques. Butina clustering categorizes molecules based on their structural similarity (indicated by the Tanimoto coefficient) to create a structurally diverse training dataset. The learning method combines various individual pharmacophore models into a set of pharmacophore models for pharmacophore space optimization in virtual screening.Results: This approach was evaluated on Apelin datasets and afforded good screening performance, as proven by Receiver Operating Characteristic (AUC score of 0.994 ± 0.007), enrichment factor of (EF1% of 50.07 ± 0.211), Güner-Henry score of 0.956 ± 0.015, and F-measure of 0.911 ± 0.031.Discussion: Although one of the high-scoring models achieved statistically superior results in each dataset (AUC of 0.82; an EF1% of 19.466; GH of 0.131 and F1-score of 0.071), the ensemble learning method including voting and stacking method balanced the shortcomings of each model and passed with close performance measures.
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| 5. |
- Le, Ha V., et al.
(författare)
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A sulfonate ligand-defected Zr-based metal-organic framework for the enhanced selective removal of anionic dyes
- 2024
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Ingår i: RSC Advances. - 2046-2069. ; 14:23, s. 16389-16399
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we introduce a novel defective analogue of the representative 6-connected zirconium-based metal-organic framework (MOF-808), by employing 5-sulfoisophthalic acid monosodium salt (H2BTC-SO3Na) as a defect inducer via a mixed-linker approach. The structural integrity and different physicochemical properties were investigated by various characterization techniques, including powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and nitrogen physisorption at 77 K. Additionally, proton nuclear magnetic resonance (1H-NMR), energy-dispersive X-ray (EDX), and inductively coupled plasma optical emission spectroscopy (ICP-OES) were employed to confirm the presence of 6.9 mol% of the 5-sulfoisophthalate ligand within the highly crystalline MOF-808 structure. The defective material exhibited significant enhancements in the removal efficiency of various organic dyes, including approximately 64% and 77% for quinoline yellow and sunset yellow, and 56% and 13% for rhodamine B and malachite green, compared to its pristine counterpart. Importantly, the defective MOF-808 showed a remarkable selectivity toward anionic species in binary-component dyes comprising both anionic and cationic dyes.
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| 6. |
- Tran, Khanh-Tung, et al.
(författare)
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Personalization for robust voice pathology detection in sound waves
- 2023
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Ingår i: Proceedings of the annual conference of the international speech communication association, INTERSPEECH. - : International Speech Communication Association. ; , s. 1708-1712
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Konferensbidrag (refereegranskat)abstract
- Automatic voice pathology detection is promising for noninvasive screening and early intervention using sound signals. Nevertheless, existing methods are susceptible to covariate shifts due to background noises, human voice variations, and data selection biases leading to severe performance degradation in real-world scenarios. Hence, we propose a non-invasive framework that contrastively learns personalization from sound waves as a pre-train and predicts latent-spaced profile features through semi-supervised learning. It allows all subjects from various distributions (e.g., regionality, gender, age) to benefit from personalized predictions for robust voice pathology in a privacy-fulfilled manner. We extensively evaluate the framework on four real-world respiratory illnesses datasets, including Coswara, COUGHVID, ICBHI, and our private dataset - ASound under multiple covariate shift settings (i.e., cross-dataset), improving up to 4.12% in overall performance.
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| 7. |
- Tan, Ha Minh, 1989-, et al.
(författare)
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Self-heating Effect on Tin Oxide Nanowire Network Gas Sensor
- 2014
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Self-heated gas sensors have attracted much of interests owing to the ultra-low power consumption as well as simple device fabrication. However, it still requires further improvement to overcome some technical difficulties such as high operation voltage, long-term stability, and mass production. In this work, we propose a nanowire nework structure to solve these problems. The self-heating effect on fabricated structures was tested and working temperature was evaluated by base resistance measurement and infrared emission microscopy methods. The fabricated sensor consumed an electric power of about 40 mW to reach the working temperature up to 250 oC. The NO2 sensing properties were initially studied on this sensor structure.
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| 8. |
- Khoa, Nguyen Manh, et al.
(författare)
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Compounds from aerial parts of Isodon lophanthoides and their effects of cytotoxicity and LPS-induced IL-1β and IL-10 production in RAW 264.7 macrophages
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Ingår i: Vietnam Journal of Chemistry. - 2572-8288.
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Tidskriftsartikel (refereegranskat)abstract
- The bioassay-guided isolation of compounds from the aerial parts of Isodon lophanthoides (IL) resulted in the identification of five compounds (1–5). The chemical structures of 1–5 were determined through spectral analyses and compared to those identified in the literature to be 4-hydroxybenzoic acid (1), protocatechuic acid (2), rosmarinic acid (3), coetsoidin B (4), and coetsoidin A (5). Compounds 1, 4, and 5 were found for the first time in the aerial parts of IL. Compounds 1 and 2 displayed potent cytotoxic activity against A549, MCF-7, HepG2, and HL60 cancer cell lines, with IC50 values ranging from 13.93 to 18.69 µm and from 11.97 to 18.30 µm, respectively. Compounds 1‒5 significantly inhibited LPS-induced IL-1β production in RAW 264.7 macrophages compared to the LPS 5 ng/mL control group, resulting in IL-1β concentrations ranging from 34.92 to 46.91 pg/mL. Additionally, compounds 1‒5 exhibited notable stimulation of IL-10 production, with IL-10 levels ranging from 358.77 to 478.23 pg/mL, compared to the LPS 5 ng/mL control group. These findings highlight the potential of compounds 1‒5 and the IL extracts for the cytotoxic effects on cancer cell lines and on LPS-induced IL-1β and IL-10 production in RAW 264.7 macrophages.
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| 9. |
- Ngo, Hai Hoang Tuan, et al.
(författare)
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Effect of light-touch intervention and associated factors to microbial contamination at small-scale pig slaughterhouses and traditional pork shops in Vietnam
- 2023
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Ingår i: International Journal of Food Microbiology. - : Elsevier. - 0168-1605 .- 1879-3460. ; 406
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Tidskriftsartikel (refereegranskat)abstract
- Traditional pork value chains dominate the production and distribution of pork in Vietnam; however, the high level of microbiological contamination in pork may increase the risk of food-borne disease for consumers. There is limited evidence about how to feasibly and scalably reduce microbial contamination in pork sold in traditional markets. This study aimed to assess the effectiveness of light-touch interventions for changing worker behaviour in small-scale slaughterhouses and vendors at traditional pork shops, as well as to identify risk factors for pork contamination. The intervention packages consisted of providing hygiene tools and delivering a food safety training which had been designed in a participatory way and covered 10 small-scale slaughterhouses and 29 pork shops. Pig carcasses, retailed pork, contact surfaces, and hands were sampled to measure the total bacterial count (TBC) and Salmonella contamination before, three and six weeks after the intervention, and trainee practices were observed at the same time. Linear and generalized linear mixed effects models were constructed to identify risk factors for TBC and Salmonella contamination at the slaughterhouses and pork shops. The interventions at slaughterhouses and pork shops both showed a slight reduction of TBC contamination in pig carcasses and Salmonella prevalence in retailed pork, while the TBC in retailed pork decreased only marginally. For slaughterhouses, the regression model indicated that smoking or eating during slaughtering (indicating poor hygienic practices) was associated with TBC increasing, while cleaning floors and wearing boots reduced TBC contamination. For pork shops, using rough materials (cardboard or wood) to display pork was the only factor increasing TBC contamination in pork, whereas cleaning knives was associated with lower TBC. Besides, the presence of supporters and wearing aprons reduced the probability of Salmonella contamination in pork. The findings highlight the effectiveness of light-touch interventions in reducing microbial contamination in pig carcasses at small-scale slaughterhouses and pork at traditional shops over the study period.
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| 10. |
- Ngo, Hoang Tuan Hai, et al.
(författare)
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Assessment of a light-touch intervention to reduce microbial contamination at small-scale pig slaughterhouses and traditional pork shops in Vietnam
- 2023
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Ingår i: International Journal of Food Microbiology. - : Elsevier. - 0168-1605 .- 1879-3460. ; 406
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Tidskriftsartikel (refereegranskat)abstract
- Traditional pork value chains dominate the production and distribution of pork in Vietnam; however, there high microbiological contamination of pork may lead to health risks. There is limited evidence about how to sustainably and scalably reduce microbial contamination in pork sold in traditional markets. This study aimed to assess the effectiveness of light-touch interventions for changing worker behaviour in small-scale slaughterhouses and retailers at traditional pork shops, as well as to identify risk factors for pork contamination. The intervention packages consisted of providing hygiene tools and delivering a food safety training which had been designed in a participatory way and covered 10 small-scale slaughterhouses and 29 pork shops. Pig carcasses, retailed pork, contact surfaces, and hands were sampled to measure the total bacterial count (TBC) and Salmonella contamination and trainee practices were observed before, three and six weeks after the intervention. Linear and generalized linear mixed effects models were constructed to identify risk factors for TBC and Salmonella contamination at the slaughterhouses and pork shops. Intervention results showed a slight reduction of TBC contamination in pig carcasses from 4.46 to 4.23 log10 CFU/cm2 (p = 0.09) and Salmonella prevalence in retailed pork (reduction from 52% to 24% detection, p = 0.08), while the TBC in retailed pork decreased only marginally (5.47 vs. 5.36 log10 CFU/g, p = 0.23). For slaughterhouses, the regression model indicated that smoking or eating during slaughtering was a risk factor, associated with TBC increasing by 0.60 log10 CFU/g (95% confidence interval (CI): 0.12 to 0.96, p =0.02), while cleaning floors and wearing boots reduced TBC contamination with 0.53 log10 CFU/g (CI: –0.83 to 0.01, p = 0.03) and 1.04 log10 CFU/g (CI: –1.50 to –0.26, p = 0.03), respectively. For pork shops, using rough materials (cardboard or wood) to display pork was the only factor increasing TBC contamination in pork with 0.57 log10 CFU/g (CI: 0.22 to 0.91, p < 0.001), whereas wearing aprons was associated with lower TBC, with 0.45 log10 CFU/g (CI: –0.79 to –0.12, p = 0.02), and Salmonella contamination in pork (odds ratio (OR) = 0.13, CI: 0.02 to 0.72, p = 0.03). The findings highlight the effectiveness of light-touch interventions in reducing microbial contamination in pig carcasses and pork over the study period.
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