29 results on '"Quoc, Viet Ha"'
Search Results
2. 0s and 1s in marine molecular research: a regional HPC perspective
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Nelina Angelova, Georgios Kotoulas, Giorgos Perantinos, Christina Pavloudi, Theodoros Danis, Dimitris Sidirokastritis, Antonis Potirakis, Vasileios Papadogiannis, Jon Bent Kristoffersen, Elena Sarropoulou, Panagiotis Kasapidis, Savvas Paragkamian, Antonios Magoulas, Christos Arvanitidis, Evangelos Pafilis, Panagiotis Vavilis, Nikos Pattakos, Anastasia Gioti, Aglaia Antoniou, Costas S. Tsigenopoulos, Jacques Lagnel, Quoc Viet Ha, Eliza Kaitetzidou, Haris Zafeiropoulos, Stelios Ninidakis, Tereza Manousaki, Hellenic Centre for Marine Research (HCMR), University of Crete [Heraklion] (UOC), Bull SAS (Bull), Bull SAS, Génétique et Amélioration des Fruits et Légumes (GAFL), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), LifeWatch European Research Infrastructure Consortium, European Project: 727315,MedAID, European Project: 652831,H2020,H2020-INFRAIA-2014-2015,AQUAEXCEL2020(2015), and European Project: 634429,H2020,H2020-SFS-2014-2,ParaFishControl(2015)
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[INFO.INFO-AR]Computer Science [cs]/Hardware Architecture [cs.AR] ,Engineering ,AcademicSubjects/SCI02254 ,computational requirements ,Marine Biology ,Health Informatics ,Review ,Computing Methodologies ,Software ,pour l'Agriculture ,Tier 2 network ,Requirements analysis ,UR1052 ,biodiversity ,l'Alimentation et l'Environnement ,business.industry ,containerization ,high-throughput sequencing ,Containerization ,Marine Biology (journal) ,research infrastructures ,Supercomputer ,marine research ,Computer Science Applications ,high performance computing ,Engineering management ,Upgrade ,aquaculture ,Key (cryptography) ,AcademicSubjects/SCI00960 ,[INFO.INFO-BI]Computer Science [cs]/Bioinformatics [q-bio.QM] ,business ,G én étique et Am élioration des Fruits et L égumes ,biotechnology - Abstract
High-performance computing (HPC) systems have become indispensable for modern marine research, providing support to an increasing number and diversity of users. Pairing with the impetus offered by high-throughput methods to key areas such as non-model organism studies, their operation continuously evolves to meet the corresponding computational challenges. Here, we present a Tier 2 (regional) HPC facility, operating for over a decade at the Institute of Marine Biology, Biotechnology, and Aquaculture of the Hellenic Centre for Marine Research in Greece. Strategic choices made in design and upgrades aimed to strike a balance between depth (the need for a few high-memory nodes) and breadth (a number of slimmer nodes), as dictated by the idiosyncrasy of the supported research. Qualitative computational requirement analysis of the latter revealed the diversity of marine fields, methods, and approaches adopted to translate data into knowledge. In addition, hardware and software architectures, usage statistics, policy, and user management aspects of the facility are presented. Drawing upon the last decade’s experience from the different levels of operation of the Institute of Marine Biology, Biotechnology, and Aquaculture HPC facility, a number of lessons are presented; these have contributed to the facility’s future directions in light of emerging distribution technologies (e.g., containers) and Research Infrastructure evolution. In combination with detailed knowledge of the facility usage and its upcoming upgrade, future collaborations in marine research and beyond are envisioned.
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- 2021
3. The IMBBC HPC facility: history, configuration, usage statistics and related activities
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Haris Zafeiropoulos, Anastasia Gioti, Stelios Ninidakis, Antonis Potirakis, Savvas Paragkamian, Nelina Angelova, Aglaia Antoniou, Theodoros Danis, Eliza Kaitetzidou, Panagiotis Kasapidis, Jon Bent Kristoffersen, Vasileios Papadogiannis, Christina Pavloudi, Quoc Viet Ha, Jacques Lagnel, Nikos Pattakos, Giorgos Perantinos, Dimitris Sidirokastritis, Panagiotis Vavilis, Georgios Kotoulas, Tereza Manousaki, Elena Sarropoulou, Costas S Tsigenopoulos, Christos Arvanitidis, Antonios Magoulas, and Evangelos Pafilis
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aquaculture ,research infrastructures (RIs) ,containerization ,computational requirements ,high performance computing (HPC) ,high-throughput sequencing (HTS) ,marine research ,biodiversity ,biotechnology - Abstract
This preprint introduces key pieces of information of the IMBBC HPC facility regarding its history, usage statistics, user management and in-house developed containers/workflows along with accompanying data. It also intends to share them to the rest of the scientific community either directly as a data-presenting paper or by accompanying sister publications (where data interpretations and conclusions are given)., HZ and NG contributed equally at this work. Correspondence to: E. Pafilis; pafilis@hcmr.gr
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- 2021
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4. Comparative Study on A Novel Pathogen of European Seabass. Diversity of Aeromonas veronii in the Aegean Sea
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Smyrli, Maria, primary, Triga, Adriana, additional, Dourala, Nancy, additional, Varvarigos, Panos, additional, Pavlidis, Michael, additional, Quoc, Viet Ha, additional, and Katharios, Pantelis, additional
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- 2019
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5. Characterization of microencapsulated powders rich in saponins from cocoa pod husk ( Theobroma cacao L.) and medicinal plant an xoa ( Helicteres hirsuta Lour.).
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Nguyen VT and Thi Tran PT
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Cocoa pod husk (CPH) is a major residue of cocoa processing industry, while medicinal plant H. hirsuta is used for treatment of malaria and diabetes mellitus in folk medicine. This study aimed to produce microencapsulated powders from saponin-enriched CPH and H. hirsuta extracts and assess their physicochemical, phytochemical, antioxidant, and α-glucosidase inhibition properties. The findings show that the microencapsulated powders were achieved diserable physicochemical properties (moisture of 3.22-4.76 %, water activity of 0.43-0.46, water solubility index of 74.18-88.77 %, particle size of 254.2-719.7 nm, and zeta potential from -6.97 to -15.1 mV). The phytochemical content of microencapsulated CPH powders gained at high levels (total saponin content of 151.87-193.46 mg EE/g DS, total flavonoid content of 33.80-46.05 mg CE/g DS), total alkaloid content of 15.20-24.23 mg AA/g DS, and total phenolic content of 5.41-6.49 mg GAE/g DS). The antioxidant potential of microencapsulated CPH powders using ARSC and FRAP assays was 15.51-18.20 and 9.61-11.89 mg TE/g DS, respectively, while their α-glucosidase inhibition capacity at 100 μg/mL was found at 51.74-52.16 %. The phytochemical content (except total alkaloid content), antioxidant, and α-glucosidase inhibitory potential of microencapsulated CPH powders were smaller than those of microencapsulated H. hirsuta and combined powders. This study reveals that the microencapsulated CPH and H. hirsuta powders were prospective in reducing hyperglycemia activity. Therefore, this study provided an evidence for further application of CPH and H. hirsuta plant for functional food development., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Author(s).)
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- 2024
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6. Associations of A20, CYLD, Cezanne and JAK2 Genes and Immunophenotype with Psoriasis Susceptibility.
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Giang NH, Lien NTK, Trang DT, Huong PT, Hoang NH, and Xuan NT
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- Humans, Cytokines metabolism, Tumor Necrosis Factor-alpha metabolism, Janus Kinase 2 genetics, Janus Kinase 2 metabolism, Deubiquitinating Enzyme CYLD metabolism, Signal Transduction, Psoriasis genetics
- Abstract
Background and Objectives : Psoriasis is an immune-mediated chronic inflammatory skin disorder and commonly associated with highly noticeable erythematous, thickened and scaly plaques. Deubiquitinase genes, such as tumor necrosis factor-alpha protein 3 (TNFAIP3, A20), the cylindromatosis (CYLD) and Cezanne, function as negative regulators of inflammatory response through the Janus kinase/signal transducers and activators of transcription (JAK-STAT) pathways. In this study, polymorphisms and expressions of A20, CYLD and Cezanne genes as well as immunophenotype in psoriatic patients were determined. Materials and Methods : In total, 82 patients with psoriasis and 147 healthy individuals with well-characterized clinical profiles were enrolled. Gene polymorphisms were determined by direct DNA sequencing, gene expression profile by quantitative real time-polymerase chain reaction (PCR), immunophenotype by flow cytometry, and the secretion of cytokines and cancer antigen (CA) 125 by enzyme-linked Immunosorbent assay (ELISA). Results : The inactivation of A20, CYLD and Cezanne and increased levels of TNF-α, IFN-γ and CA 125 was observed in psoriatic patients. Importantly, patients with low A20 expression had significant elevations of triglyceride and total cholesterol concentrations and higher numbers of CD13
+ CD117- and CD19+ CD23+ (activated B) cells than those with high A20 expression. Genetic analysis indicated that all rs4495487 SNPs in the JAK2 gene, rs200878487 SNPs in the A20 gene and four SNPs (c.1584-375, c.1584-374, rs1230581026 and p.W433R) in the Cezanne gene were associated with significant risks, while the rs10974947 variant in the JAK2 gene was at reduced risk of psoriasis. Moreover, in the Cezanne gene, p.W433R was predicted to be probably damaging by the Polyphen-2 prediction tool and an AA/CC haplotype was associated with a high risk of psoriasis. In addition, patients with higher CA 125 levels than the clinical cutoff 35 U/mL showed increased levels of IFN-γ than those with normal CA 125 levels. Conclusions : A20 expression was associated with lipid metabolism and the recruitment of CD13+ CD117- and activated B cells into circulation in psoriatic patients. Besides this, the deleterious effect of the p.W433R variant in the Cezanne gene may contribute to the risk of psoriasis.- Published
- 2023
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7. Earthworms can mobilize soil arsenic through their casts.
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Dang QT, Nguyen ATQ, Kieu HT, Pham QV, Tran TTT, Nguyen TTH, Dinh VM, and Nguyen MN
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- Animals, Humans, Soil, Oxides, Arsenic analysis, Oligochaeta metabolism, Soil Pollutants analysis, Oryza metabolism
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The mobilization of arsenic (As) in paddy soil has received much attention because it might accelerate the transfer of As from soil to rice. This study aims to elucidate whether earthworms can mobilize As through their casts. Cast samples were collected from 23 different paddy fields in the Red River delta. We first analysed different forms of As through fractionation and then performed batch experiments under reducing conditions to identify factors that govern the mobility of As in casts. Because the dissociation of casts may induce colloids that carry As, the colloidal properties of cast suspensions were also examined. The median value of As in casts (obtained from aqua regia digestion) was 5.11 mg kg
-1 , which was lower than that in the surrounding soil (6.7 mg kg-1 ). Compared with the surrounding soil, casts contain less As, possibly because cast As is more labile and more easily lost due to leaching. Various processes, including the reductive dissolution of Fe oxides, decomposition of organic matter, and sorption competition of soluble anionic substances, such as P, Si and DOC, were found to strongly correlate with the release of As from casts. We propose that earthworms, via their casts, may accelerate the As cycle in paddy soils, potentially intensifying As exposure to human health. The dissociation of cast could release colloids containing As; therefore, the cotransport of As with cast-induced colloids should also be considered in future works., Competing Interests: Declaration of competing interest The author declares that he has no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)- Published
- 2023
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8. Sorption of cosmetic and personal care polymer ingredients to iron oxides, clay minerals and soil clays: An environmental perspective.
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Nguyen DT, Nguyen MT, Le TQ, Duong LH, Nguyen AQ, Pham ATM, Dinh VM, Nguyen AD, Nguyen-Thanh L, and Nguyen MN
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- Clay, Aluminum Silicates, Minerals, Kaolin, Oxides, Iron, Colloids, Adsorption, Soil, Polymers
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The increasing daily use of cosmetic and personal care ingredients (CPCIs) requires improved understanding of the fate and impacts of CPCIs in environmental systems. Effects of CPCIs on colloidal properties of various geocolloids such as iron oxides (goethite, haematite), clay minerals (kaolinite, bentonite) and soil clays (kaolinitic-, illitic- and lateritic soil clays) were studied by tracking time-resolved changes in zeta potential (ζ) and observing suspended particle density. Two polymers representing anionic CPCIs, i.e., polyacrylate crosspolymer-11 (PC11) and cationic CPCIs, i.e., polyDADMAC (PD) show contrast effects on ζ and colloidal properties of the selected materials. While PC11 tended to associate with Fe oxides, PD can be adsorbed by clay minerals and soil clays. The neutralization due to the sorption of either PC11 or PD onto opposite-charge sign surface sites can lower the net surface charge of the materials, thereby enhancing electrostatic attraction, stimulating particle size growth, and eventually intensifying co-aggregation. The observed colloidal properties of iron oxides, clay minerals and soil clays under the presence of PC11 and PD may reflect what are happening in many aquatic environments where CPCIs co-exist with various mineral colloids. Therein, CPCIs likely delay the transport of the opposite-charge sign colloids, while they increase the dispersibility and transportability of the same-charge sign colloids. This implies that intensifying presence of a given CPCI could have selective effects on colloid systems. As a whole, CPCIs can change the fate and the final destination of mineral colloids and themselves; therefore, their effects and relevant treatment techniques need to be included into the future agenda., Competing Interests: Declaration of competing interest The author declares that he has no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)
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- 2023
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9. Crystallization Pathways and Evolution of Morphologies and Structural Defects of α-MnO 2 under Air Annealing.
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Dinh VP, Luu TA, Siemek K, Kozlenko DP, Le KH, Dang NT, Nguyen TV, Le Phuc N, Tran TD, Phan PT, Lo ST, Hoang KAT, Dinh TK, Luong NT, Le NC, Nguyen NT, Ho TH, Tran XD, Tran PD, and Nguyen HQ
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Manganese dioxide nanomaterials have wide applications in many areas from catalysis and Li-ion batteries to gas sensing. Understanding the crystallization pathways, morphologies, and formation of defects in their structure is particularly important but still a challenging issue. Herein, we employed an arsenal of X-ray diffraction (XRD), scanning electron microscopy (SEM), neutron diffraction, positron annihilation spectroscopies, and ab initio calculations to investigate the evolution of the morphology and structure of α-MnO
2 nanomaterials prepared via reduction of KMnO4 solution with C2 H5 OH prior to being annealed in air at 200-600 °C. We explored a novel evolution that α-MnO2 nucleation can be formed even at room temperature and gradually developed to α-MnO2 nanorods at above 500 °C. We also found the existence of H+ or K+ ions in the [1 × 1] tunnels of α-MnO2 and observed the simultaneous presence of Mn and O vacancies in α-MnO2 crystals at low temperatures. Increasing the temperature removed these O vacancies, leaving only the Mn vacancies in the samples.- Published
- 2022
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10. Base-catalyzed multicomponent access to quinoxalin-2-thiones from o -phenylenediamines, aryl ketones and sulfur.
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Nguyen TB, Mac DH, Tran TMC, Nguyen BN, and Cao HT
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- Acetophenones, Catalysis, Dimethyl Sulfoxide, Ketones, Methanol, Phenylenediamines, Piperidines, Sulfur, Quinoxalines, Thiones
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3-Arylquinoxaline-2-thiones were conveniently synthesized via three-component oxidative condensation of acetophenones with o -phenylenediamines and sulfur in DMSO in the presence of piperidine as a catalyst. The products could be readily isolated from the reaction mixture by simple precipitation and washing with methanol. This set of reaction conditions applied to higher homologs of acetophenones as well as benzyl phenyl ketones led to 2,3-di- C -substituted quinoxalines. Further functionalization of 3-phenylquinoxaline-2-thione via reaction on the thione group could be readily performed to provide quinoxaline derivatives in good yields.
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- 2022
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11. Effects of Supplemental Light Spectra on the Composition, Production and Antimicrobial Activity of Ocimum basilicum L. Essential Oil.
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Chu HTT, Vu TN, Dinh TTT, Do PT, Chu HH, Tien TQ, Tong QC, Nguyen MH, Ha QT, and Setzer WN
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- Gas Chromatography-Mass Spectrometry, Plant Oils pharmacology, Anti-Infective Agents pharmacology, Ocimum basilicum, Oils, Volatile pharmacology
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This study was performed to investigate the effects of different supplemental light spectra and doses (duration and illuminance) on the essential oil of basil (Ocimum basilicum L.) cultivated in the net-house in Vietnam during four months. Ten samples of basil aerial parts were hydrodistilled to obtain essential oils which had the average yields from 0.88 to 1.30% (v/w, dry). The oils analyzed using GC-FID and GC-MS showed that the main component was methyl chavicol (87.4−90.6%) with the highest values found in the oils of basil under lighting conditions of 6 h/day and 150−200 µmol·m−2·s−1. Additional lighting conditions caused the significant differences (p < 0.001) in basil biomass and oil production with the highest values found in the oils of basil under two conditions of (1) 71% Red: 20% Blue: 9.0% UVA in at 120 μmol·m−2·s−1 in 6 h/day and (2) 43.5% Red: 43.5% Blue: 8.0% Green: 5.0% Far-Red at 100 μmol·m−2·s−1 in 6 h/day. The oils of basil in some formulas showed weak inhibitory effects on only the Bacillus subtilis strain. Different light spectra affect the biomass and essential oil production of basil, as well as the concentrations of the major components in the oil.
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- 2022
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12. Magnetoimpedance Biosensors and Real-Time Healthcare Monitors: Progress, Opportunities, and Challenges.
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Jimenez VO, Hwang KY, Nguyen D, Rahman Y, Albrecht C, Senator B, Thiabgoh O, Devkota J, Bui VDA, Lam DS, Eggers T, and Phan MH
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- Delivery of Health Care, Electric Impedance, Humans, Magnetics, Biosensing Techniques, COVID-19 diagnosis
- Abstract
A small DC magnetic field can induce an enormous response in the impedance of a soft magnetic conductor in various forms of wire, ribbon, and thin film. Also known as the giant magnetoimpedance (GMI) effect, this phenomenon forms the basis for the development of high-performance magnetic biosensors with magnetic field sensitivity down to the picoTesla regime at room temperature. Over the past decade, some state-of-the-art prototypes have become available for trial tests due to continuous efforts to improve the sensitivity of GMI biosensors for the ultrasensitive detection of biological entities and biomagnetic field detection of human activities through the use of magnetic nanoparticles as biomarkers. In this review, we highlight recent advances in the development of GMI biosensors and review medical devices for applications in biomedical diagnostics and healthcare monitoring, including real-time monitoring of respiratory motion in COVID-19 patients at various stages. We also discuss exciting research opportunities and existing challenges that will stimulate further study into ultrasensitive magnetic biosensors and healthcare monitors based on the GMI effect.
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- 2022
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13. Learning acoustic responses from experiments: A multiscale-informed transfer learning approach.
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Trinh VH, Guilleminot J, Perrot C, and Vu VD
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A methodology to learn acoustical responses based on limited experimental datasets is presented. From a methodological standpoint, the approach involves a multiscale-informed encoder used to cast the learning task in a finite-dimensional setting. A neural network model mapping parameters of interest to the latent variables is then constructed and calibrated using transfer learning and knowledge gained from the multiscale surrogate. The relevance of the approach is assessed by considering the prediction of the sound absorption coefficient for randomly-packed rigid spherical beads of equal diameter. A two-microphone method is used in this context to measure the absorption coefficient on a set of configurations with various monodisperse particle diameters and sample thicknesses, and a hybrid numerical approach relying on the Johnson-Champoux-Allard-Pride-Lafarge model is deployed as the multiscale-based predictor. It is shown that the strategy allows for the relationship between the micro-/structural parameters and the experimental acoustic response to be well approximated, even if a small physical dataset (comprised of ten samples) is used for training. The methodology, therefore, enables the identification and validation of acoustical models under constraints related to data limitation and parametric dependence. It also paves the way for an efficient exploration of the parameter space for acoustical materials design.
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- 2022
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14. Identification of Fish Species and Toxins Implicated in a Snapper Food Poisoning Event in Sabah, Malaysia, 2017.
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Dao HV, Uesugi A, Uchida H, Watanabe R, Matsushima R, Lim ZF, Jipanin SJ, Pham KX, Phan MT, Leaw CP, Lim PT, and Suzuki T
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- Adult, Animals, Ciguatera Poisoning epidemiology, Female, Humans, Malaysia epidemiology, Male, Middle Aged, Seafood classification, Treatment Outcome, Ciguatoxins chemistry, Ciguatoxins toxicity, Fishes classification, Foodborne Diseases, Seafood toxicity, Toxins, Biological analysis, Toxins, Biological toxicity
- Abstract
In the coastal countries of Southeast Asia, fish is a staple diet and certain fish species are food delicacies to local populations or commercially important to individual communities. Although there have been several suspected cases of ciguatera fish poisoning (CFP) in Southeast Asian countries, few have been confirmed by ciguatoxins identification, resulting in limited information for the correct diagnosis of this food-borne disease. In the present study, ciguatoxin-1B (CTX-1B) in red snapper ( Lutjanus bohar ) implicated in a CFP case in Sabah, Malaysia, in December 2017 was determined by single-quadrupole selected ion monitoring (SIM) liquid chromatography/mass spectrometry (LC/MS). Continuous consumption of the toxic fish likely resulted in CFP, even when the toxin concentration in the fish consumed was low. The identification of the fish species was performed using the molecular characterization of the mitochondrial cytochrome c oxidase subunit I gene marker, with a phylogenetic analysis of the genus Lutjanus . This is the first report identifying the causative toxin in fish-implicated CFP in Malaysia.
- Published
- 2021
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15. Bioactive compounds from Physalis angulata and their anti-inflammatory and cytotoxic activities.
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Tuan Anh HL, Le Ba V, Do TT, Phan VK, Pham Thi HY, Bach LG, Tran MH, Tran Thi PA, and Kim YH
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- Anti-Inflammatory Agents pharmacology, Molecular Structure, Vietnam, Physalis, Withanolides pharmacology
- Abstract
A new compound, physalucoside A ( 1 ), together with seven withanolides ( 2 - 8 ) and three flavonoids ( 9 - 11 ), were isolated from Physalis angulata L. (Solanaceae), a medicinal plant native to Vietnam. The chemical structures of these compounds were elucidated by one- and two-dimensional NMR spectra, high-resolution electrospray ionization mass spectrometry analyses, and chemical reactivity. The anti-inflammatory and cytotoxic activities of isolated compounds were also evaluated. These data suggest that the anti-inflammatory activity of P. angulata is due primarily to its withanolide content. This study demonstrates the potential of withanolides as promising candidates for the development of new anti-inflammatory drugs.
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- 2021
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16. New Reactions of Contraction of the o -Quinone Ring with the Formation of Derivatives of 2-(2-Indolyl)-cyclopenta[b]pyrrole-3,4-diones and Pyrindino[1,2-a]indoles: A Combined Experimental and Density Functional Theory Investigation.
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Sayapin YA, Dorogan IV, A Gusakov E, Bang DN, Tkachev VV, Tupaeva IO, Tran DL, Nguyen TV, Duong TN, Vu Dinh H, A Krasnikova T, M Aldoshin S, and Minkin VI
- Abstract
Derivatives of 2-(2-indolyl)-cyclopenta[b]pyrrole-3,4-diones and pyrindino[1,2-a]indoles were synthesized by a new reaction of contraction of the o -quinone ring, and their structures were investigated by X-ray crystallography and nuclear magnetic resonance spectroscopy. The mechanisms of the reactions were suggested based on density functional theory calculations of the critical parts of the potential energy surfaces., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)
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- 2021
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17. Influence of Additional Micro-Sized Particles of Dy-Nd-Cu-Al on Magnetic Properties of Sintered Nd-Fe-B Magnets.
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Thanh PT, Oanh DTK, Yen NH, and Dan NH
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In this work, we investigated the influence of concentration of the additional micro-sized particles of Dy
40 Nd30 Al30 and Nd40 Cu30 Al30 on magnetic properties of the sintered Nd16.5 Fe77 B6.5 magnets. The additional particles with size in the range of 1-3 μ m were prepared by ball milling method and then mixed into micrometer Nd16.5 Fe77 B6.5 master powder with different weight fractions before magnetic anisotropic pressing, vacuum sintering and annealing. The results show that the coercivity of the sintered Nd-Fe-B magnets can be improved considerably by introducing additional particles to the grain boundaries. The improvement of the coercivity H c of the magnets is clearly dependent on the composition and concentration of the additional microparticles. The H c increases linearly from 8.5 kOe to 17 kOe with increasing the weight fraction of the Dy40 Nd30 Al30 microparticles from 0 to 5%. Meanwhile, the coercivity of the magnet reaches a maximum value of 11.7 kOe with 4 wt% addition of Nd40 Cu30 Al30 . The quite high maximum energy products, (BH)max >30 MGOe, were also obtained for the magnets added with the microparticles. The obtained hard magnetic parameters of the magnets can be applied in practice.- Published
- 2021
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18. Unusual hydrogen implanted gold with lattice contraction at increased hydrogen content.
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Nguyen KT, Hiep Vuong V, Nguyen TN, Nguyen TT, Yamamoto T, and Hoang NN
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The experimental evidence for the contraction of volume of gold implanted with hydrogen at low doses is presented. The contraction of lattice upon the addition of other elements is very rare and extraordinary in the solid-state, not only for gold but also for many other solids. To explain the underlying physics, the pure kinetic theory of absorption is not adequate and the detailed interaction of hydrogen in the lattice needs to be clarified. Our analysis points to the importance of the formation of hydride bonds in a dynamic manner and explains why these bonds become weak at higher doses, leading to the inverse process of volume expansion frequently seen in metallic hydrogen containers.
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- 2021
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19. Author Correction: Crystal structure of Type IX secretion system PorE C-terminal domain from Porphyromonas gingivalis in complex with a peptidoglycan fragment.
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Trinh NTT, Tran HQ, Van Dong Q, Cambillau C, Roussel A, and Leone P
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- 2021
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20. Multi-Response Optimization of Electrical Discharge Drilling Process of SS304 for Energy Efficiency, Product Quality, and Productivity.
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Nguyen TT, Tran VT, and Mia M
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The electrical discharge drilling (EDD) process is an effective machining approach to produce various holes in difficult-to-cut materials. However, the energy efficiency of the EDD operation has not thoroughly been considered in published works. The aim of the current work is to optimize varied parameters for enhancing the material removal rate (MRR), saving drilled energy (ED), and decreasing the expansion of the hole (HE) for the EDD process. Three advanced factors, including the gap voltage adjustor (GAP), capacitance parallel connection (CAP), and servo sensitivity selection (SV), are considered. The predictive models of the performances were proposed with the support of the adaptive neuro-based fuzzy inference system (ANFIS). An integrative approach combining the analytic hierarchy process (AHP) and the neighborhood cultivation genetic algorithm (NCGA) was employed to select optimal factors. The findings revealed the optimal values of the CAP, GAP, and SV were 6, 5, and 4, respectively. Moreover, the ED and HE were decreased by 16.78% and 28.68%, while the MRR was enhanced by 89.72%, respectively, as compared to the common setting values. The explored outcome can be employed as a technical solution to enhance the energy efficiency, drilled quality, and productivity of the EDD operation.
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- 2020
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21. Hydrothermal Synthesis of Cobalt Doped Magnetite Nanoparticles for Corrosion Protection of Epoxy Coated Reinforced Steel.
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Truc TA, Hoan NX, Bach DT, Thuy TT, Ramadass K, Sathish CI, Chinh NT, Trinh ND, and Hoang T
- Abstract
Magnetite (Fe³O⁴) and Cobalt-doped Fe³O⁴ nanoparticles were obtained by hydrothermal reaction. The synthesized products were characterized by X-ray diffraction, Energy dispersive spectroscopy, Scanning electron microscopy, and Zeta potential. The results show that Co was substituted in the Fe³O⁴ crystal structure as CoFe₂O₄ phase. The synthesized materials are nanometer in size having uniform morphology, negatively charged and cobalt concentration varied from 2.5 to 7.5 wt.%. The magnetite and Co-doped magnetite nanoparticles at a low concentration (3 wt.%) were dispersed in the epoxy resin. The effect of the magnetite and Co-doped magnetite nanoparticles on the anticorrosion performance of the protective epoxy coatings covered on carbon steel surface was characterized by Electrochemical Impedance Spectroscopy (EIS) and salt fog exposure. Codoped magnetite nanoparticles at 2.5 wt.% provided high protection of the coatings. In addition, Pull-off tests confirmed an adhesion improvement of the epoxy coating filled by the Co-doped Fe³O⁴ nanoparticles.
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- 2020
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22. Crystal structure of Type IX secretion system PorE C-terminal domain from Porphyromonas gingivalis in complex with a peptidoglycan fragment.
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Trinh NTT, Tran HQ, Van Dong Q, Cambillau C, Roussel A, and Leone P
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- Bacterial Proteins genetics, Bacterial Secretion Systems genetics, Crystallography, X-Ray, Membrane Proteins genetics, Porphyromonas gingivalis genetics, Protein Domains, Bacterial Proteins chemistry, Bacterial Secretion Systems chemistry, Membrane Proteins chemistry, Porphyromonas gingivalis chemistry
- Abstract
Porphyromonas gingivalis, the major human pathogen associated to periodontal diseases, utilizes the Bacteroidetes-specific type IX secretion system (T9SS) to export virulence factors. PorE is a periplasmic multi-domain lipoprotein associated to the outer membrane that was recently identified as essential for T9SS function. Little is known on T9SS at the structural level, and in particular its interaction with peptidoglycan. This prompted us to carry out structural studies on PorE full length as well as on its four isolated domains. Here we report the crystal structure of the C-terminal OmpA_C-like putative peptidoglycan-binding domain at 1.55 Å resolution. An electron density volume was identified in the protein cleft, making it possible to build a naturally-occurring peptidoglycan fragment. This result suggests that PorE interacts with peptidoglycan and that PorE could anchor T9SS to the cell wall.
- Published
- 2020
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23. Micron-Size White Bamboo Fibril-Based Silane Cellulose Aerogel: Fabrication and Oil Absorbent Characteristics.
- Author
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Nguyen DD, Vu CM, Vu HT, and Choi HJ
- Abstract
Micron-size white bamboo fibrils were fabricated from white bamboo and used as a source for the production of highly porous and very lightweight cellulose aerogels for use as a potential oil absorbent. The aerogels were fabricated through gelation from an aqueous alkali hydroxide/urea solution, followed by a conventional freeze-drying process. The morphology and physical properties of the aerogels were characterized by field emission scanning electron microscopy and Brunauer-Emmett-Teller surface area analysis, respectively. Successful silanization of the cellulose aerogel was confirmed by energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and water contact angle measurements. The fabricated silane cellulose aerogel exhibited excellent absorption performance for various oil and organic solvents with typical weight gains ranging from 400% to 1200% of their own dry weight, making them promising versatile absorbents for a range of applications, including water purification.
- Published
- 2019
- Full Text
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24. Gold nanoparticles as an outstanding catalyst for the hydrogen evolution reaction.
- Author
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Tran TD, Nguyen MTT, Le HV, Nguyen DN, Truong QD, and Tran PD
- Abstract
An electrode made of Au nanoparticles, ca. 13 nm in diameter, displays outstanding catalytic activity for the hydrogen evolution reaction in water. At an overpotential of 200 mV it operates with a catalytic rate TOF of 0.3 s-1, which is among the best performances ever achieved for a Pt-free H2-evolving catalyst.
- Published
- 2018
- Full Text
- View/download PDF
25. A global phylogeny of the fern genus Tectaria (Tectariaceae: Polypodiales) based on plastid and nuclear markers identifies major evolutionary lineages and suggests repeated evolution of free venation from anastomosing venation.
- Author
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Zhang L, Zhou XM, Chen DK, Schuettpelz E, Knapp R, Lu NT, Luong TT, Dang MT, Duan YF, He H, Gao XF, and Zhang LB
- Subjects
- Bayes Theorem, DNA, Plant chemistry, DNA, Plant isolation & purification, DNA, Plant metabolism, Ferns anatomy & histology, Ferns genetics, Phylogeny, Plant Proteins classification, Plant Proteins genetics, Plastids genetics, Ribulose-Bisphosphate Carboxylase classification, Ribulose-Bisphosphate Carboxylase genetics, Sequence Analysis, DNA, Evolution, Molecular, Ferns classification, Plastids classification
- Abstract
Tectaria (Tectariaceae) is one of the most confusing fern genera in terms of its circumscription and phylogeny. Since its original description, a number of genera had been moved into or related with this genus, while others had been segregated from it. Tectaria is also among the largest fern genera, comprising 150-210 mostly tropical species. Previous molecular studies have been far from comprehensive (sampling no more than 76 accessions from 52 species), limited in geographic scope (mainly restricted to Asia), and based exclusively on plastid markers. In the present study, DNA sequences of eight plastid and one nuclear marker of 360 accessions representing ca. 130 species of Tectaria, ca. 36 species of six non-Tectaria genera in Tectariaceae, 12 species of Davalliaceae, Oleandraceae, and Polypodiaceae, and 13 species of Lomariopsidaceae were used to infer a phylogeny with maximum likelihood, Bayesian inference, and maximum parsimony approaches. Our major results include: (1) the most recently proposed circumscription of Tectaria is strongly supported as monophyletic; (2) the genera Lenda, Microbrochis, Phlebiogonium, and Sagenia, sampled here for the first time, are resolved as part of Tectaria; (3) four superclades representing early splits in Tectaria are identified, with the Old World species being sister to the New World species; (4) 12 well-supported major clades in Tectaria are revealed, differing from one another in molecular, morphological, and geographical features; (5) evolution of 13 morphological characters is inferred in a phylogenetic context and morphological synapomorphies of various clades are identified; and in particular (6) free venation in Tectaria is inferred to be repeatedly derived from anastomosing venation, an evolutionary phenomenon not documented previously in vascular plants in a phylogenetic context based on both plastid and nuclear evidence., (Copyright © 2017 Elsevier Inc. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
26. High-throughput biodiversity analysis: Rapid assessment of species richness and ecological interactions of Chrysomelidae (Coleoptera) in the tropics.
- Author
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Gómez-Zurita J, Cardoso A, Coronado I, De la Cadena G, Jurado-Rivera JA, Maes JM, Montelongo T, Nguyen DT, and Papadopoulou A
- Abstract
Biodiversity assessment has been the focus of intense debate and conceptual and methodological advances in recent years. The cultural, academic and aesthetic impulses to recognise and catalogue the diversity in our surroundings, in this case of living objects, is furthermore propelled by the urgency of understanding that we may be responsible for a dramatic reduction of biodiversity, comparable in magnitude to geological mass extinctions. One of the most important advances in this attempt to characterise biodiversity has been incorporating DNA-based characters and molecular taxonomy tools to achieve faster and more efficient species delimitation and identification, even in hyperdiverse tropical biomes. In this assay we advocate for a broad understanding of Biodiversity as the inventory of species in a given environment, but also the diversity of their interactions, with both aspects being attainable using molecular markers and phylogenetic approaches. We exemplify the suitability and utility of this framework for large-scale biodiversity assessment with the results of our ongoing projects trying to characterise the communities of leaf beetles and their host plants in several tropical setups. Moreover, we propose that approaches similar to ours, establishing the inventories of two ecologically inter-related and species-rich groups of organisms, such as insect herbivores and their angiosperm host-plants, can serve as the foundational stone to anchor a comprehensive assessment of diversity, also in tropical environments, by subsequent addition of trophic levels.
- Published
- 2016
- Full Text
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27. Subtle Ecological Gradient in the Tropics Triggers High Species-Turnover in a Local Geographical Scale.
- Author
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Nguyen DT and Gómez-Zurita J
- Subjects
- Animals, Coleoptera classification, Electron Transport Complex IV genetics, Insect Proteins genetics, Mitochondrial Proteins genetics, Vietnam, Biodiversity, Coleoptera physiology, Tropical Climate
- Abstract
Our perception of diversity, including both alpha- and beta-diversity components, depends on spatial scale. Studies of spatial variation of the latter are just starting, with a paucity of research on beta-diversity patterns at smaller scales. Understanding these patterns and the processes shaping the distribution of diversity is critical to describe this diversity, but it is paramount in conservation too. Here, we investigate the diversity and structure of a tropical community of herbivorous beetles at a reduced local scale of some 10 km2, evaluating the effect of a small, gradual ecological change on this structure. We sampled leaf beetles in the Núi Chúa National Park (S Vietnam), studying changes in alpha- and beta-diversity across an elevation gradient up to 500 m, encompassing the ecotone between critically endangered lowland dry deciduous forest and mixed evergreen forest at higher elevations. Leaf beetle diversity was assessed using several molecular tree-based species delimitation approaches (with mtDNA cox1 data), species richness using rarefaction and incidence-based diversity indexes, and beta-diversity was investigated decomposing the contribution of species turnover and nestedness. We documented 155 species in the area explored and species-richness estimates 1.5-2.0x higher. Species diversity was similar in both forest types and changes in alpha-diversity along the elevation gradient showed an expected local increase of diversity in the ecotone. Beta-diversity was high among forest paths (average Sørensen's dissimilarity = 0.694) and, tentatively fixing at 300 m the boundary between otherwise continuous biomes, demonstrated similarly high beta-diversity (Sørensen's dissimilarity = 0.581), with samples clustering according to biome/elevation. Highly relevant considering the local scale of the study, beta-diversity had a high contribution of species replacement among locales (54.8%) and between biomes (79.6%), suggesting environmental heterogeneity as the dominant force shaping diversity at such small scale, directly and indirectly on the plant communities. Protection actions in the Park, especially these addressed at the imperative conservation of dry forest, must ponder the small scale at which processes shape species diversity and community structure for inconspicuous, yet extraordinarily diverse organisms such as the leaf beetles.
- Published
- 2016
- Full Text
- View/download PDF
28. In vitro and in vivo targeting effect of folate decorated paclitaxel loaded PLA-TPGS nanoparticles.
- Author
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Thu HP, Nam NH, Quang BT, Son HA, Toan NL, and Quang DT
- Abstract
Paclitaxel is one of the most effective chemotherapeutic agents for treating various types of cancer. However, the clinical application of paclitaxel in cancer treatment is considerably limited due to its poor water solubility and low therapeutic index. Thus, it requires an urgent solution to improve therapeutic efficacy of paclitaxel. In this study, folate decorated paclitaxel loaded PLA-TPGS nanoparticles were prepared by a modified emulsification/solvent evaporation method. The obtained nanoparticles were characterized by Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared (FTIR) and Dynamic Light Scattering (DLS) method. The spherical nanoparticles were around 50 nm in size with a narrow size distribution. Targeting effect of nanoparticles was investigated in vitro on cancer cell line and in vivo on tumor bearing nude mouse. The results indicated the effective targeting of folate decorated paclitaxel loaded copolymer nanoparticles on cancer cells both in vitro and in vivo.
- Published
- 2015
- Full Text
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29. New data of three rare belondirid species (Nematoda, Dorylaimida, Belondiridae) from Vietnam, with the first record and description of the male of Oxybelondiraparaperplexa Ahmad & Jairajpuri, 1979.
- Author
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Nguyen DT, Vu TT, Bonkowski M, and Peña-Santiago R
- Abstract
Three rare nematode species of the family Belondiridae, originally described from and only known to occur in India are recorded for the first time in Vietnam: Axonchiumthoubalicum, Belondiramurtazai and Oxybelondiraparaperplexa. It is the first report of these three genera in this country. The three species are described, including new morphological data, morphometrics and light microscope pictures. The male of Oxybelondiraparaperplexa is collected and described for the first time. It is characterized by its 1.54 mm long body, ad-cloacal pair of genital papillae situated at 9.0 µm from the cloacal aperture, only one ventromedian supplement located at 15 µm from the ad-cloacal pair within the range of spicules, spicules slightly curved ventrad and 42 µm long (7 times as long as wide and 2 times as long as cloacal body diameter), and tail 100 µm long (c = 15, c' = 5) and similar to that of the female.
- Published
- 2014
- Full Text
- View/download PDF
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