85 results on '"Dang, HT"'
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2. Diagnostic Accuracy of Microscopic Observation Drug Susceptibility (MODS) Assay for Pediatric Tuberculosis in Hanoi, Vietnam
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Tran, ST, Renschler, JP, Le, HT, Dang, HT, Dao, TM, Pham, AN, Nguyen, LT, Van Nguyen, H, Thi Thu Nguyen, T, Ngoc Le, S, Fox, A, Caws, M, Thi Quynh Nguyen, N, Horby, P, and Wertheim, H
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Multidisciplinary ,Science ,lcsh:R ,Medicine ,Correction ,lcsh:Medicine ,lcsh:Q ,lcsh:Science - Abstract
[This corrects the article on p. e72100 in vol. 8.].
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- 2016
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3. Iodine status in gate pregnancy and psychosocial determinants of iodized salt use in rural northern Viet Nam
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Fisher, J, Thach, T, Biggs, B, Tuan, T, Dwyer, T, Casey, G, Dang, HT, Hetzel, B, Fisher, J, Thach, T, Biggs, B, Tuan, T, Dwyer, T, Casey, G, Dang, HT, and Hetzel, B
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OBJECTIVE: To establish iodine status among pregnant women in rural northern Viet Nam and explore psychosocial predictors of the use of iodized salt in their households. METHODS: This prospective study included pregnant women registered in health stations in randomly-selected communes in Ha Nam province. At recruitment (< 20 weeks of gestation), sociodemographic factors, reproductive health, intimate partner relationship, family violence, symptoms of common mental disorders and use of micronutrient supplements were assessed. During a second assessment (> 28 weeks of gestation) a urine specimen was collected to measure urinary iodine concentration (UIC) and iodized salt use was assessed. Predictors were explored through univariable analyses and multivariable linear and logistic regression. FINDINGS: The 413 pregnant women who provided data for this study had a median UIC of 70 µg/l; nearly 83% had a UIC lower than the 150 µg/l recommended by the World Health Organization; only 73.6% reported using iodized salt in any form in their households. Iodized salt use was lower among nulliparous women (odds ratio, OR: 0.56; 95% confidence interval, CI: 0.32-0.96); less educated women (OR: 0.34; 95% CI: 0.16-0.71); factory workers or small-scale traders (OR: 0.52; 95% CI: 0.31-0.86), government workers (OR: 0.35; 95% CI: 0.13-0.89) and women with common mental disorders at recruitment (OR: 0.61; 95% CI: 0.38-0.98). CONCLUSION: The decline in the use of iodized salt in Viet Nam since the National Iodine Deficiency Disorders Control Programme was suspended in 2005 has placed pregnant women and their infants in rural areas at risk of iodine deficiency disorders.
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- 2011
4. Vitamin B 1 , B 2 , and B 6 Intakes and Risk of Gastric Cancer: Findings from a Case-Control Study.
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Le NT, Pham YT, Dang HT, Le LT, Huynh NY, Cullen J, and Luu HN
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- Humans, Case-Control Studies, Male, Middle Aged, Female, Vietnam epidemiology, Risk Factors, Aged, Odds Ratio, Adult, Logistic Models, Vitamin B Complex administration & dosage, Stomach Neoplasms epidemiology, Stomach Neoplasms prevention & control, Stomach Neoplasms etiology, Vitamin B 6 administration & dosage, Riboflavin administration & dosage, Diet statistics & numerical data, Thiamine administration & dosage
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Background/objectives: Gastric cancer is one of the leading malignancies worldwide. B vitamins play important roles in DNA synthesis and methylation because they are considered co-enzymes in one-carbon metabolism. There is inconclusive evidence regarding the associations between dietary vitamins B
1 , B2 , and B6 with the risk of gastric cancer in different epidemiologic studies. We, therefore, investigated such associations in a hospital-based case-control study comprising 1182 incident cases of gastric cancer and 2995 controls in Vietnam., Methods: Dietary vitamins B1 , B2 , and B6 were derived from a semi-quantitative validated food frequency questionnaire. An unconditional logistic regression model was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of gastric cancer in relation to dietary intake of vitamins B1 , B2 , and B6 ., Results: Overall, dietary vitamins B1 (ORper-SD increment = 0.83; 95% CI: 0.78-0.89; Ptrend < 0.001) and B6 (ORper-SD increment = 0.88; 95% CI: 0.81-0.94; Ptrend < 0.001) were associated with a reduced risk of gastric cancer. Compared with the lowest quintile, the ORs (95% CIs) of gastric cancer for quintiles 2, 3, 4, and 5 of the vitamin B1 intake were 0.64 (0.51-0.79), 0.54 (0.43-0.69), 0.57 (0.44-0.74), and 0.42 (0.31-0.55), respectively; for vitamin B6 intake, quintiles 2, 3, 4, and 5 were 0.53 (0.42-0.66), 0.54 (0.42-0.70), 0.61 (0.46-0.81), and 0.46 (0.33-0.63), respectively. This inverse association was not different across sex, BMI, and smoking statuses. No association was found between dietary vitamin B2 and gastric cancer risk., Conclusions: Dietary vitamins B1 and B6 were associated with a reduced risk of gastric cancer in the Vietnamese population. Future studies are warranted to replicate our findings, which also have great implications for gastric cancer prevention and control programs in low- and middle-income countries.- Published
- 2024
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5. Enhanced energy storage performance in BaZr x Ti 1- x O 3 lead-free ferroelectrics near phase transitions.
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Vu BH, Dang HT, Dinh VH, and Lich LV
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The present study explores the energy storage properties of BaZr
x Ti1-xO3 through phase-field modeling, focusing on the impact of composition and temperature on energy storage performance. The obtained results reveal a variety of polarization phases and configurations based on Zr compositions and temperatures. A detailed phase diagram for temperature-composition of BaZrx Ti1-xO3 is established, closely aligning with experimental measurements. Variations in Zr content and temperature have a significant impact on the polarization-electric field ( P - E ) response, influencing the energy storage properties. Calculations of energy storage properties are derived from the P - E response. In addition, a thorough diagram is developed to illustrate the discharge energy density of BaZrx Ti1-xO3 as a function of temperature and composition. Notably, high discharge energy density is achievable near the Curie temperature, corresponding to the transition from ferroelectric to paraelectric phase. Furthermore, the present study emphasizes the importance of the disparity between maximum and remanent polarization, as well as the electric field-dependent effective permittivity, in determining the discharge energy density., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)- Published
- 2024
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6. Empowering Women Living with HIV/AIDS in Vietnam: A Hybrid Online-Offline Intervention to Combat Stigma.
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Lin C, Nguyen BD, Nguyen TT, Dang HT, Li L, and Giang LM
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- Humans, Female, Vietnam, Adult, Middle Aged, Social Support, Empowerment, Social Media, Pilot Projects, Surveys and Questionnaires, Power, Psychological, Internet, Social Stigma, Adaptation, Psychological, HIV Infections psychology
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Women living with HIV/AIDS (WLHA) encounter numerous challenges, such as stigma and gender disparities, that hinder their access to care, especially in patriarchal societies like Vietnam. We developed a hybrid intervention with online and offline (in-person) components to empower WLHA in Vietnam. The intervention was pilot tested with 91 WLHA in Hanoi. During baseline and 4-month, study investigators delivered two in-person sessions, one Zoom session, and 15 weeks of Zalo (social media platform) discussions to enhance positive coping strategies, treatment utilization and adherence, and engagement of support from family and peers. The participants continued their Zalo discussions from 4-month to 6-month without investigators' involvement. Intervention outcomes, including active coping and perceived barriers to care, were evaluated at baseline, 4-, and 6-month surveys. Mixed-effects regression models showed that the participants' active coping significantly increased from baseline (50.5 ± 9.4) to 4-month (53.8 ± 6.2; p = 0.0001), although there was a slight decrease at 6-month (52.8 ± 7.2), the change from 4-month to 6-month was not significantly significant (p = 0.3256). There was a significant reduction in participants' perceived barriers to care, from 19.8 ± 5.2 at baseline to 17.4 ± 5.2 at 4-month (p < 0.0001), which remained stable at 17.8 ± 4.3 at 6-month (p < 0.0001 compared to baseline). This intervention presents a promising model to empower WLHA in Vietnam and potentially in similar global contexts. Future interventions could benefit from leveraging natural peer leaders and adopting a more person-centered approach to meet WLHA's varying needs., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
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- 2024
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7. Identification of immune-associated genes with altered expression in the spleen of mice enriched with probiotic Lactobacillus species using rna-seq profiling.
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Truong DA, Tran HTT, Chu NT, Phan L, Phan HT, Dang HT, Nguyen A, and Dang HV
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Objective: Probiotics are living microorganisms that can provide health benefits when consumed. Here, we investigated the effects of probiotics on gene expression in the spleen of mice using RNA-sequencing analysis between negative control and probiotic groups (including 4 Lactobacillus strains: Lactobacillus fermentum, L. casei, L. plantarum, and L. brevis)., Methods: Mice exposed with probiotic in 4 weeks by intragastric administration. Then, spleen tissues of the control and probiotics groups were collected on days 14 and 28 for RNA sequencing., Results: In total, 665, 186, and 81 DEGs were significantly expressed on day 14 vs. control, day 28 vs. control groups, and probiotics day 28 vs. day 14 groups, respectively. On the other hand, 12 Toll-like receptor (TLR) genes underwent additional validation through qRT-PCR, affirming the increased alignment between qRT-PCR and RNA-Seq findings. In addition, the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses revealed that the DEGs were predominantly enriched in defense responses to pathogens, including inflammatory bowel diseases, malaria, leukaemia virus 1, and herpes virus, as well as immune processes related to immune response and signal transduction. This study represents the first investigation into mice's gene expression in the spleen exposed to probiotics using Lactobacillus spp. isolated from a field strain in Vietnam., Conclusion: Our results provide valuable insights into the impacts and functions of probiotics on mammalian development, offering crucial information for the potential therapeutic use of probiotics in defending against pathogens in Vietnam. The findings from this study highlight the potential of probiotics in modulating gene expression in the spleen, which may have implications for immune function and overall health in mice.
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- 2024
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8. Triple burden of malnutrition among Vietnamese 0·5-11-year-old children in 2020-2021: results of SEANUTS II Vietnam.
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Tran NT, Tran VK, Tran DT, Nguyen TTN, Nguyen SD, Nguyen HT, Nguyen TS, Thanh Le TV, Nguyen PTL, Dang HT, Le HA, Wong G, and Khouw I
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- Humans, Vietnam epidemiology, Child, Preschool, Female, Cross-Sectional Studies, Male, Infant, Prevalence, Child, Malnutrition epidemiology, Urban Population statistics & numerical data, Child Nutrition Disorders epidemiology, Vitamin D Deficiency epidemiology, Vitamin D Deficiency blood, Overweight epidemiology, Southeast Asian People, Nutritional Status, Growth Disorders epidemiology, Rural Population statistics & numerical data, Thinness epidemiology
- Abstract
Objective: SEANUTS II Vietnam aims to obtain an in-depth understanding of the nutritional status and nutrient intake of children between 0·5 and 11·9 years old., Design: Cross-sectional survey., Setting: A multistage cluster systematic random sampling method was implemented in different regions in Vietnam: North Mountainous, Central Highlands, Red River Delta, North Central and Coastal Area, Southeast and Mekong River Delta., Participants: 4001 children between 6 months and 11·9 years of age., Results: The prevalence of stunting and underweight was higher in rural than in urban children, whereas overweight and obese rates were higher in urban areas. 12·0 % of the children had anaemia and especially children 0·5–1 year old were affected (38·6 %). Low serum retinol was found in 6·2 % of children ≥ 4 years old. The prevalence of vitamin D insufficiency was 31·1 % while 60·8 % had low serum Zn. For nutrient intake, overall, 80·1 % of the children did not meet the estimated energy requirements. For Ca intake, ∼60 % of the younger children did not meet the RNI while it was 92·6 % in children >7 years old. For vitamin D intake, 95·0 % of the children did not meet recommended nutrient intakes., Conclusions: SEANUTS II Vietnam indicated that overnutrition was more prevalent than undernutrition in urban areas, while undernutrition was found more in rural areas. The high prevalence of low serum Zn, vitamin D insufficiency and the inadequate intakes of Ca and vitamin D are of concern. Nutrition strategies for Vietnamese children should consider three sides of malnutrition and focus on approaches for the prevention of malnutrition.
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- 2024
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9. Acridine photocatalysis enables tricomponent direct decarboxylative amine construction.
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Sui X, Dang HT, Porey A, Trevino R, Das A, Fremin SO, Hughes WB, Thompson WT, Dhakal SK, Arman HD, and Larionov OV
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Amines are centrally important motifs in medicinal chemistry and biochemistry, and indispensable intermediates and linchpins in organic synthesis. Despite their cross-disciplinary prominence, synthetic access to amine continues to rely on two-electron approaches based on reductions and additions of organometallic reagents, limiting their accessible chemical space and necessitating stepwise preassembly of synthetic precursors. We report herein a homogeneous photocatalytic tricomponent decarboxylative radical-mediated amine construction that enables modular access to α-branched secondary amines directly from the broad and structurally diverse chemical space of carboxylic acids in a tricomponent reaction with aldehydes and aromatic amines. Our studies reveal the key role of acridine photocatalysis acting in concert with copper and Brønsted acid catalytic processes in facilitating the previously inaccessible homogeneous photocatalytic reaction and provide a streamlined segue to a wide range of amines and nonproteinogenic α-amino acids., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)
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- 2024
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10. Promising clinical and immunological efficacy of Bacillus clausii spore probiotics for supportive treatment of persistent diarrhea in children.
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Dang HT, Tran DM, Phung TTB, Bui ATP, Vu YH, Luong MT, Nguyen HM, Trinh HT, Nguyen TT, Nguyen AH, and Van Nguyen AT
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- Infant, Humans, Child, Spores, Bacterial, Diarrhea therapy, Cytokines, Bacillus clausii, Probiotics therapeutic use
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Persistent diarrhea is a severe gastroenteric disease with relatively high risk of pediatric mortality in developing countries. We conducted a randomized, double-blind, controlled clinical trial to evaluate the efficacy of liquid-form Bacillus clausii spore probiotics (LiveSpo CLAUSY; 2 billion CFU/5 mL ampoule) at high dosages of 4-6 ampoules a day in supporting treatment of children with persistent diarrhea. Our findings showed that B. clausii spores significantly improved treatment outcomes, resulting in a 2-day shorter recovery period (p < 0.05) and a 1.5-1.6 folds greater efficacy in reducing diarrhea symptoms, such as high frequency of bowel movement of ≥ 3 stools a day, presence of fecal mucus, and diapered infant stool scale types 4-5B. LiveSpo CLAUSY supportive treatment achieved 3 days (p < 0.0001) faster recovery from diarrhea disease, with 1.6-fold improved treatment efficacy. At day 5 of treatment, a significant decrease in blood levels of pro-inflammatory cytokines TNF-α, IL-17, and IL-23 by 3.24% (p = 0.0409), 29.76% (p = 0.0001), and 10.87% (p = 0.0036), respectively, was observed in the Clausy group. Simultaneously, there was a significant 37.97% decrease (p = 0.0326) in the excreted IgA in stool at day 5 in the Clausy group. Overall, the clinical study demonstrates the efficacy of B. clausii spores (LiveSpo CLAUSY) as an effective symptomatic treatment and immunomodulatory agent for persistent diarrhea in children.Trial registration: NCT05812820., (© 2024. The Author(s).)
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- 2024
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11. HyPedSim: A Multi-Level Crowd-Simulation Framework-Methodology, Calibration, and Validation.
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Dang HT, Gaudou B, and Verstaevel N
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Large-scale crowd phenomena are complex to model because the behaviour of pedestrians needs to be described at both strategic, tactical, and operational levels and is impacted by the density of the crowd. Microscopic models manage to mimic the dynamics at low densities, whereas mesoscopic models achieve better performances in dense situations. This paper proposes and evaluates a novel agent-based model to enable agents to dynamically change their operational model based on local density. The ability to combine microscopic and mesoscopic models for multi-scale simulation is studied through a use case of pedestrians at the Festival of Lights, Lyon, France. Pedestrian outflow data are extracted from video recordings of exiting crowds at the festival. The hybrid model is calibrated and validated using a genetic algorithm that optimises the match between simulated and observed outflow data. Additionally, a local sensitivity analysis is then conducted to identify the most sensitive parameters in the model. Finally, the performance of the hybrid model is compared to different models in terms of density map and computation time. The results demonstrate that the hybrid model has the capacity to effectively simulate pedestrians across varied density scenarios while optimising computational performance compared to other models.
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- 2024
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12. The solitary wasp genus Orancistrocerus from Vietnam, with descriptions of two new species (Hymenoptera, Vespidae, Eumeninae).
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Nguyen LTP, Nguyen AD, and Dang HT
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New data are presented for the potter wasp genus Orancistrocerus van der Vecht (Eumeninae, Odynerini) occurring in Vietnam. Two species are described as new to science: Orancistrocerusthanhnhat sp. nov. and O.thanghen sp. nov. Orancistrocerusaterrimuserythropus van der Vecht is synonymized with Orancistrocerusaterrimusaterrimus (de Saussure); the male genitalia of this species are described for the first time. An updated key is presented to all species of the genus., Competing Interests: The authors have declared that no competing interests exist., (Lien Thi Phuong Nguyen, Anh D. Nguyen, Hoa T. Dang.)
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- 2024
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13. Selective C-H Activation of Molecular Nanodiamonds via Photoredox Catalysis.
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Dang HT, O'Callaghan HT, Wymore MM, Suarez J, and Martin DBC
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While substituted adamantanes have widespread use in medicinal chemistry, materials science, and ligand design, the use of diamantanes and higher diamondoids is limited to a much smaller number. Selective functionalization beyond adamantane is challenging, as the number of very similar types of C-H bonds (secondary, 2°, and tertiary, 3°) increases rapidly, and H atom transfer does not provide a general solution for site selectivity. We report a method using pyrylium photocatalysts that is effective for nanodiamond functionalization in up to 84% yield with exclusive 3° selectivity and moderate levels of regioselectivity between 3° sites. The proposed mechanism involving photooxidation, deprotonation, and radical C-C bond formation is corroborated through Stern-Volmer luminescence quenching, cyclic voltammetry, and EPR studies. Our photoredox strategy offers a versatile approach for the streamlined synthesis of diamondoid building blocks., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)
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- 2024
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14. Economically viable co-production of methanol and sulfuric acid via direct methane oxidation.
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Im J, Cheong SH, Dang HT, Kim NK, Hwang S, Lee KB, Kim K, Lee H, and Lee U
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The direct oxidation of methane to methanol has been spotlighted research for decades, but has never been commercialized. This study introduces cost-effective process for co-producing methanol and sulfuric acid through a direct oxidation of methane. In the initial phase, methane oxidation forms methyl bisulfate (CH
3 OSO3 H), then transformed into methyl trifluoroacetate (CF3 CO2 CH3 ) via esterification, and hydrolyzed into methanol. This approach eliminates the need for energy-intensive separation of methyl bisulfate from sulfuric acid by replacing the former with methyl trifluoroacetate. Through the superstructure optimization, our sequential process reduces the levelized cost of methanol to nearly two-fold reduction from the current market price. Importantly, this process demonstrates adaptability to smaller gas fields, assuring its economical operation across a broad range of gas fields. The broader application of this process could substantially mitigate global warming by utilizing methane, leading to a significantly more sustainable and economically beneficial methanol industry., (© 2023. The Author(s).)- Published
- 2023
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15. Kinetically-driven reactivity of sulfinylamines enables direct conversion of carboxylic acids to sulfinamides.
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Dang HT, Porey A, Nand S, Trevino R, Manning-Lorino P, Hughes WB, Fremin SO, Thompson WT, Dhakal SK, Arman HD, and Larionov OV
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Sulfinamides are some of the most centrally important four-valent sulfur compounds that serve as critical entry points to an array of emergent medicinal functional groups, molecular tools for bioconjugation, and synthetic intermediates including sulfoximines, sulfonimidamides, and sulfonimidoyl halides, as well as a wide range of other S(iv) and S(vi) functionalities. Yet, the accessible chemical space of sulfinamides remains limited, and the approaches to sulfinamides are largely confined to two-electron nucleophilic substitution reactions. We report herein a direct radical-mediated decarboxylative sulfinamidation that for the first time enables access to sulfinamides from the broad and structurally diverse chemical space of carboxylic acids. Our studies show that the formation of sulfinamides prevails despite the inherent thermodynamic preference for the radical addition to the nitrogen atom, while a machine learning-derived model facilitates prediction of the reaction efficiency based on computationally generated descriptors of the underlying radical reactivity., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)
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- 2023
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16. Silver nanoparticle toxicity on Artemia parthenogenetica nauplii hatched on axenic tryptic soy agar solid medium.
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Do MA, Dang HT, Doan NT, Pham HLT, Tran TA, Le VCT, Young T, and Le DV
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- Animals, Silver toxicity, Artemia, Agar pharmacology, Ecotoxicology, Culture Media pharmacology, Metal Nanoparticles toxicity
- Abstract
The use of gnobiotic brine shrimp (Artemia spp.) for ecotoxicology and bacteria-host interaction studies is common. However, requirements for axenic culture and matrix effects of seawater media can be an obstacle. Thus, we investigated the hatching ability of Artemia cysts on a novel sterile Tryptic Soy Agar (TSA) medium. Herein, we demonstrate for the first time that Artemia cysts can hatch on a solid medium without liquid, which offers practical advantages. We further optimized the culture conditions for temperature and salinity and assessed this culture system for toxicity screening of silver nanoparticles (AgNPs) across multiple biological endpoints. Results revealed that maxima hatching (90%) of embryos occurred at 28 °C and without addition of sodium chloride. When capsulated cysts were cultured on TSA solid medium Artemia were negatively impacted by AgNPs at 30-50 mgL
-1 in terms of the embryo hatching ratio (47-51%), umbrella- to nauplii-stage transformation ratio (54-57%), and a reduction in nauplii-stage growth (60-85% of normal body length). At 50-100 mgL-1 AgNPs and higher, evidence of damage to lysosomal storage was recorded. At 500 mgL-1 AgNPs, development of the eye was inhibited and locomotory behavior impeded. Our study reveals that this new hatching method has applications in ecotoxicology studies and provides an efficient means to control axenic requirements to produce gnotobiotic brine shrimp., (© 2023. The Author(s).)- Published
- 2023
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17. Decarboxylative Triazolation Enables Direct Construction of Triazoles from Carboxylic Acids.
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Dang HT, Nguyen VD, Haug GC, Arman HD, and Larionov OV
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Triazoles have major roles in chemistry, medicine, and materials science, as centrally important heterocyclic motifs and bioisosteric replacements for amides, carboxylic acids, and other carbonyl groups, as well as some of the most widely used linkers in click chemistry. Yet, the chemical space and molecular diversity of triazoles remains limited by the accessibility of synthetically challenging organoazides, thereby requiring preinstallation of the azide precursors and restricting triazole applications. We report herein a photocatalytic, tricomponent decarboxylative triazolation reaction that for the first time enables direct conversion of carboxylic acids to triazoles in a single-step, triple catalytic coupling with alkynes and a simple azide reagent. Data-guided inquiry of the accessible chemical space of decarboxylative triazolation indicates that the transformation can improve access to the structural diversity and molecular complexity of triazoles. Experimental studies demonstrate a broad scope of the synthetic method that includes a variety of carboxylic acid, polymer, and peptide substrates. When performed in the absence of alkynes, the reaction can also be used to access organoazides, thereby obviating preactivation and specialized azide reagents and providing a two-pronged approach to C-N bond-forming decarboxylative functional group interconversions., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)
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- 2023
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18. Economic Evaluation of a Global Reconstructive Surgery Visiting Educator Program.
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Luan A, Meyers N, Le Thua TH, Dang HT, Phu QV, Auten B, and Chang J
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Objective: The objective of this study was to quantify the cost-effectiveness and economic value of a reconstructive surgery visiting educator trip program in a resource-constrained setting., Background: Reconstructive surgical capacity remains inadequate in low- and middle-income countries, resulting in chronic disability and a significant economic toll. Education and training of the local surgical workforce to sustainably expand capacity have been increasingly encouraged, but economic analyses of these interventions are lacking., Methods: Data were analyzed from 12 visiting educator trips and independently-performed surgical procedures at 3 Vietnamese hospitals between 2014 and 2019. A cost-effectiveness analysis was performed using standardized methodology and thresholds to determine cost-effectiveness. Sensitivity analyses were performed with disability weights, discounting, and costs from different perspectives. Economic benefit was estimated using both the human capital method and the value of a statistical life method, and a benefit-cost ratio was computed., Results: In the base case analysis, the visiting educator program was very cost-effective at $581 per disability-adjusted life year (DALY) averted. Economic benefit was between $21·6 million and $29·3 million, corresponding to a 12- to 16-fold return on investment. Furthermore, when considering only costs to the organization, the cost decreased to $61 per DALY averted, with a 113- to 153-fold return on investment for the organization., Conclusions: Visiting educator programs, which build local reconstructive surgical capacity in limited-resource environments, can be very cost-effective with significant economic benefit and return on investment. These findings may help guide organizations, donors, and policymakers in resource allocation in global surgery., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc.)
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- 2022
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19. TVGG Dental Implant Identification System.
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Guo J, Tsai PW, Xue X, Wu D, Van QT, Kaluarachchi CN, Dang HT, and Chintha N
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Identifying the right accessories for installing the dental implant is a vital element that impacts the sustainability and the reliability of the dental prosthesis when the medical case of a patient is not comprehensive. Dentists need to identify the implant manufacturer from the x-ray image to determine further treatment procedures. Identifying the manufacturer is a high-pressure task under the scaling volume of patients pending in the queue for treatment. To reduce the burden on the doctors, a dental implant identification system is built based on a new proposed thinner VGG model with an on-demand client-server structure. We propose a thinner version of VGG16 called TVGG by reducing the number of neurons in the dense layers to improve the system's performance and gain advantages from the limited texture and patterns in the dental radiography images. The outcome of the proposed system is compared with the original pre-trained VGG16 to verify the usability of the proposed system., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Guo, Tsai, Xue, Wu, Van, Kaluarachchi, Dang and Chintha.)
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- 2022
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20. Vitamin D intake and gastric cancer in Viet Nam: a case-control study.
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Nguyen MT, Huynh NNY, Nguyen DD, Ta NH, Van Nguyen T, Dang HT, and Le NT
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- Case-Control Studies, Female, Humans, Male, Nutritional Status, Risk Factors, Vietnam epidemiology, Vitamin D, Helicobacter Infections, Stomach Neoplasms epidemiology, Stomach Neoplasms etiology
- Abstract
Background: Most recent laboratory studies have suggested a promising role of vitamin D and its analogs as novel chemotherapeutic agents for cancer treatment. However, epidemiological evidence, especially regarding the effects of vitamin D on gastric cancer is still inconsistent., Objectives: Our research aimed to evaluate the associations between vitamin D intake and the risk of developing gastric cancer through a case-control study in North Vietnam., Methods: We accessed databases of the previous completed case-control studies to derive 1182 incident gastric cancer cases and 2995 hospital controls selected from hospitals in Hanoi from 2003 to 2019. Vitamin D intake was computed by multiplying the food frequency intake with nutrient content based on the Viet Nam Food Composition Tables. Data were collected through face-to-face interviews by trained interviewers using the validated semi-quantitative food frequency and demographic lifestyle questionnaires. The odds ratio and 95% confidence interval (OR and 95%CI) were estimated using unconditional logistic regression analysis., Results: We observed a continual decline in gastric cancer risk according to the level-up of vitamin D intake in both genders, men, and women [Fifth vs. bottom quintile, OR, 95%CI: 0.68 (0.53, 0.86), OR, 95%CI: 0.72 (0.53, 0.97), OR, 95%CI: 0.58 (0.38, 0.89), respectively. Per increment quintile, the statistically significant decreased risk was seen by 7% in men and 13% in women. The significant inverse association between vitamin D intake remained in the subgroups of ever and never tobacco smoking; negative and positive H. pylori infection., Conclusion: The findings suggested that sufficient vitamin D intake was associated with a lower risk of Gastric Cancer in the Vietnamese population., (© 2022. The Author(s).)
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- 2022
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21. Use of Autoreactive Antibodies in Blood of Patients with Pancreatic Intraductal Papillary Mucinous Neoplasms (IPMN) for Grade Distinction and Detection of Malignancy.
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Brindl N, Boekhoff H, Bauer AS, Gaida MM, Dang HT, Kaiser J, Hoheisel JD, and Felix K
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(1) Background: A reliable non-invasive distinction between low- and high-risk pancreatic intraductal papillary mucinous neoplasms (IPMN) is needed to effectively detect IPMN with malignant potential. This would improve preventative care and reduce the risk of developing pancreatic cancer and overtreatment. The present study aimed at exploring the presence of autoreactive antibodies in the blood of patients with IPMN of various grades of dysplasia. (2) Methods: A single-center cohort was studied composed of 378 serum samples from patients with low-grade IPMN ( n = 91), high-grade IPMN ( n = 66), IPMN with associated invasive cancer ( n = 30), pancreatic ductal adenocarcinoma (PDAC) stages T1 ( n = 24) and T2 ( n = 113), and healthy controls ( n = 54). A 249 full-length recombinant human protein microarray was used for profiling the serum samples. (3) Results: 14 proteins were identified as potential biomarkers for grade distinction in IPMN, yielding high specificity but mediocre sensitivity. (4) Conclusions: The identified autoantibodies are potential biomarkers that may assist in the detection of malignancy in IPMN patients.
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- 2022
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22. Automatic question answering for multiple stakeholders, the epidemic question answering dataset.
- Author
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Goodwin TR, Demner-Fushman D, Lo K, Wang LL, Dang HT, and Soboroff IM
- Subjects
- Humans, COVID-19, Pandemics
- Abstract
One of the effects of COVID-19 pandemic is a rapidly growing and changing stream of publications to inform clinicians, researchers, policy makers, and patients about the health, socio-economic, and cultural consequences of the pandemic. Managing this information stream manually is not feasible. Automatic Question Answering can quickly bring the most salient points to the user's attention. Leveraging a collection of scientific articles, government websites, relevant news articles, curated social media posts, and questions asked by researchers, clinicians, and the general public, we developed a dataset to explore automatic Question Answering for multiple stakeholders. Analysis of questions asked by various stakeholders shows that while information needs of experts and the public may overlap, satisfactory answers to these questions often originate from different information sources or benefit from different approaches to answer generation. We believe that this dataset has the potential to support the development of question answering systems not only for epidemic questions, but for other domains with varying expertise such as legal or finance., (© 2022. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)
- Published
- 2022
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23. Direct radical functionalization methods to access substituted adamantanes and diamondoids.
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Weigel WK 3rd, Dang HT, Feceu A, and Martin DBC
- Abstract
Adamantane derivatives have diverse applications in the fields of medicinal chemistry, catalyst development and nanomaterials, owing to their unique structural, biological and stimulus-responsive properties, among others. The synthesis of substituted adamantanes and substituted higher diamondoids is frequently achieved via carbocation or radical intermediates that have unique stability and reactivity when compared to simple hydrocarbon derivatives. In this review, we discuss the wide range of radical-based functionalization reactions that directly convert diamondoid C-H bonds to C-C bonds, providing a variety of products incorporating diverse functional groups (alkenes, alkynes, arenes, carbonyl groups, etc .). Recent advances in the area of selective C-H functionalization are highlighted with an emphasis on the H-atom abstracting species and their ability to activate the particularly strong C-H bonds that are characteristic of these caged hydrocarbons, providing insights that can be applied to the C-H functionalization of other substrate classes.
- Published
- 2021
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24. Relaxor-Ferroelectric Films for Dielectric Tunable Applications: Effect of Film Thickness and Applied Electric Field.
- Author
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Nguyen MD, Tran DT, Dang HT, Nguyen CTQ, Rijnders G, and Vu HN
- Abstract
The dielectric properties, tunability and figure-of-merit ( FOM ) of relaxor Pb
0.9 La0.1 (Zr0.52 Ti0.48 )O3 (PLZT) films have been investigated. Dielectric measurements indicated that the dielectric constant (at zero-bias field), tunability and FOM are enhanced as the film thickness increases, which are mainly attributed to the presence of an interfacial layer near the film-electrode interface. Experimental results illustrated that a slight reduction is observed in both dielectric constant and tunability (-2%) in a wide-frequency range (10 kHz-1 MHz); meanwhile, the FOM value decreases significantly (-17%) with increasing frequency, arising from the higher dielectric loss value. The 1000-nm PLZT film shows the largest tunability of 94.6% at a maximum electric-field of 1450 kV/cm, while the highest FOM factor is 37.6 at 1000 kV/cm, due to the combination of medium tunability (88.7%) and low dielectric loss (0.0236). All these excellent results indicated that the relaxor PLZT films are promising candidates for specific applications in microwave devices.- Published
- 2021
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25. Investigation of the influence of TiO 2 distribution on HA/TiO 2 composite wetting ability using the dispersant SDBS, high-temperature annealing, and ultrasonication.
- Author
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Hoang VQ, Vu TH, Dang HT, Kim MI, and Bark CW
- Subjects
- Cell Survival, Drug Stability, HeLa Cells, Hot Temperature, Humans, Materials Testing, Sonication, Wettability, Benzenesulfonates chemistry, Durapatite chemistry, Durapatite pharmacokinetics, Durapatite pharmacology, Nanostructures chemistry, Surface-Active Agents chemistry, Titanium chemistry, Titanium pharmacokinetics, Titanium pharmacology
- Abstract
The use of composites such as hydroxyapatite (HA)/TiO
2 in bioapplications has attracted increasing attention in recent years. Herein, for the enhancement wetting ability and biocompatibility, the HA/TiO2 composite was subjected to different treatments to improve nanoparticle (NP) distribution and surface energy with an aim of mitigating nanotoxicity concerns. The treatments included ultrasonication, high-temperature annealing, and addition of a dispersant and surfactant, sodium dodecylbenzenesulfonate (SDBS). Contact angle measurement tests revealed the effect of SDBS addition on the distribution of TiO2 NPs on the HA surface: a decrease in the contact angle and, thus, an increase in the wetting ability of the HA/TiO2 composite were observed. The combination of annealing and SDBS addition treatments allowed for guest TiO2 particles to be uniformly distributed on the surface of the host HA particles, showing a rapid conversion from a hydrophobic to superhydrophilic property. In vitro investigation suggested that the cell viabilities of annealed HA/TiO2 , SDBS-added HA/TiO2 , and SDBS-added and annealed HA/TiO2 reached 89.7%, 94.7%, and 95.8%, respectively, while those of HA and untreated HA/TiO2 were 80.3% and 86.9%, respectively. The modified composites exhibited lower cytotoxicities than the unmodified systems (HA and HA/TiO2 ). Furthermore, the cell adhesion behavior of the composites was confirmed through actin-4',6-Diamidino-2-phenylindole (DAPI) staining, which showed negligible changes in the cytoskeleton architecture of the cells. This study confirmed that a modified HA/TiO2 composite has potential for bioapplications., (© 2021 IOP Publishing Ltd.)- Published
- 2021
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26. Ancestral haplotype reconstruction in endogamous populations using identity-by-descent.
- Author
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Finke K, Kourakos M, Brown G, Dang HT, Tan SJS, Simons YB, Ramdas S, Schäffer AA, Kember RL, Bućan M, and Mathieson S
- Subjects
- Algorithms, Animals, Chromosome Mapping methods, Computer Simulation, Gene Frequency, Genetic Linkage, Genotype, Humans, Linkage Disequilibrium, Models, Genetic, Pedigree, Polymorphism, Single Nucleotide, Software, Whole Genome Sequencing, DNA Copy Number Variations, Genome-Wide Association Study methods, Haplotypes, Population Dynamics
- Abstract
In this work we develop a novel algorithm for reconstructing the genomes of ancestral individuals, given genotype or sequence data from contemporary individuals and an extended pedigree of family relationships. A pedigree with complete genomes for every individual enables the study of allele frequency dynamics and haplotype diversity across generations, including deviations from neutrality such as transmission distortion. When studying heritable diseases, ancestral haplotypes can be used to augment genome-wide association studies and track disease inheritance patterns. The building blocks of our reconstruction algorithm are segments of Identity-By-Descent (IBD) shared between two or more genotyped individuals. The method alternates between identifying a source for each IBD segment and assembling IBD segments placed within each ancestral individual. Unlike previous approaches, our method is able to accommodate complex pedigree structures with hundreds of individuals genotyped at millions of SNPs. We apply our method to an Old Order Amish pedigree from Lancaster, Pennsylvania, whose founders came to North America from Europe during the early 18th century. The pedigree includes 1338 individuals from the past 12 generations, 394 with genotype data. The motivation for reconstruction is to understand the genetic basis of diseases segregating in the family through tracking haplotype transmission over time. Using our algorithm thread, we are able to reconstruct an average of 224 ancestral individuals per chromosome. For these ancestral individuals, on average we reconstruct 79% of their haplotypes. We also identify a region on chromosome 16 that is difficult to reconstruct-we find that this region harbors a short Amish-specific copy number variation and the gene HYDIN. thread was developed for endogamous populations, but can be applied to any extensive pedigree with the recent generations genotyped. We anticipate that this type of practical ancestral reconstruction will become more common and necessary to understand rare and complex heritable diseases in extended families., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2021
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27. Impairment in activities of daily living and readmission in older patients with heart failure: a cohort study.
- Author
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Nguyen TV, Dang HT, Burns MJ, Dao HH, and Nguyen TN
- Subjects
- Aged, Aged, 80 and over, Cohort Studies, Female, Geriatric Assessment, Humans, Male, Patient Readmission, Prospective Studies, Vietnam, Activities of Daily Living, Heart Failure epidemiology
- Abstract
Objectives: This study aims to investigate the prevalence of impairment of activities of daily living (ADLs) in older patients with heart failure (HF), and to examine the impact of ADL impairment on readmission after discharge., Design and Settings: A prospective cohort study was conducted in patients aged ≥65 years with HF admitted to a tertiary hospital in Vietnam from August 2016 to June 2017. Difficulties with six ADLs were assessed by a questionnaire. Participants were classified into two categories (with and without ADL impairment). The associations of ADL impairment with 3-month readmission were examined using logistic regression models., Results: There were 180 participants (mean age 80.6±8.2, 50% female) and 26.1% were classified as having ADL impairment. The most common impaired activity was bathing (21.1%), followed by transferring (20.0%), toileting (12.2%), dressing (8.9%), eating (3.3%), and continence (2.8%). During 3-month follow-up, 32.8% of the participants were readmitted to hospitals (55.3% in participants with ADL impairment, 24.8% in those without ADL impairment, p<0.001). ADL impairment significantly increased the risk of 3-month readmission (adjusted OR 2.75, 95% CI 1.25 to 6.05, p=0.01)., Conclusions: In summary, ADL impairment was common in older hospitalised patients with HF and was associated with increased readmission. These findings suggest further studies on ADL assessment and intervention during transition care for older patients with HF after discharge to prevent readmission., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2021
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28. Z-Selective Dienylation Enables Stereodivergent Construction of Dienes and Unravels a Ligand-Driven Mechanistic Dichotomy.
- Author
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Dang HT, Nguyen VD, Haug GC, Vuong NTH, Arman HD, and Larionov OV
- Abstract
Development of stereoselective and efficient reactions for construction of conjugated dienes and polyenes has remained at the forefront of organic chemistry, due to their key roles in medicinal chemistry, organic synthesis, and materials science. The synthesis of conjugated dienes and polyenes is typically accomplished in a multistep manner by sequential installation of individual C=C bonds because it allows for control of stereoselectivity and efficiency of formation of each double bond. A conceptually distinct dienylation approach entails a stereoselective appendage of a four-carbon unit, shortcutting diene synthesis. Dienylation with sulfolene provided a direct route to E -dienes, but the synthesis of substantially more challenging Z -dienes remained elusive. Here, we report that a highly Z-selective dienylation can be now achieved by a simple adjustment of a ligand, enabling stereodivergent synthesis of E - and Z -dienes from one reagent and in one step. A detailed mechanistic investigation of the E - and Z -selective dienylation provided insight into the divergent behavior of the two catalytic systems and revealed that differences in relative stabilities of catalytically active palladium phosphine complexes have a major impact on the stereochemical outcomes of the dienylation., Competing Interests: The authors declare no competing financial interest.
- Published
- 2021
- Full Text
- View/download PDF
29. Utilization of Leather Waste Fibers in Polymer Matrix Composites Based on Acrylonitrile-Butadiene Rubber.
- Author
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Hang LT, Viet DQ, Linh NPD, Doan VA, Dang HT, Dao VD, and Tuan PA
- Abstract
In this study, we present the fabrication of nitrile butadiene rubber/waste leather fiber (NBR/WLF) composites with different weight percentages of WLF and NBR (0/100, 20/80, 30/70, 40/60, 50/50, 60/40 wt / wt ). WLF was prepared by cutting the scrap leathers from the waste product of the Vietnamese leather industry. Subsequently, in order to make the short fibers, it was mixed by a hammer mill. The characteristics of WLF/NBR composites such as mechanical properties (tensile strength, tear strength, hardness), dynamic mechanical properties, toluene absorption, and morphology were carefully evaluated. As a result, the tensile strength and tear strength become larger with increasing WLF content from 0 to 50 wt% and they decrease when further increasing WLF content. The highest tensile strength of 12.5 MPa and tear strength of 72.47 N/mm were achieved with the WLF/NBR ratio of 50/50 wt%. Both hardness and resistance of the developed materials with toluene increased with increasing WLF content. The SEM results showed a good adhesion of NBR matrix and the WLF. The increasing of storage modulus (E') in comparison with raw NBR showed good compatibility between WLF and NBR matrix. This research showed that the recycled material from waste leather and NBR was successfully prepared and has great potential for manufacturing products such as floor covering courts and playgrounds, etc.
- Published
- 2020
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30. Antileishmanial activity of a new chloroquine analog in an animal model of Leishmania panamensis infection.
- Author
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Herrera L, Llanes A, Álvarez J, Degracia K, Restrepo CM, Rivera R, Stephens DE, Dang HT, Larionov OV, Lleonart R, and Fernández PL
- Subjects
- Animals, Chloroquine therapeutic use, Disease Models, Animal, Female, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Pharmaceutical Preparations, Antiprotozoal Agents therapeutic use, Leishmania, Leishmaniasis drug therapy
- Abstract
Leishmania panamensis is a relevant causative agent of tegumentary leishmaniasis in several Latin American countries. Available antileishmanial drugs have several limitations including relatively high toxicity, difficult administration, high production costs and the emergence of resistance in circulating strains. Therefore, the identification of new molecules as potential therapeutics for leishmaniasis is of great relevance. Here, we developed a murine model of L. panamensis infection and evaluated the effect of a new compound in vivo. After treatment of animals with the compound, we observed a significant reduction of inflammation and parasite load at the inoculation site, in a dose-dependent manner. We observed a reduction in IL-10 production by popliteal lymph nodes cells of infected mice. These results pave the way for future evaluation of this compound as a potential antileishmanial drug or as a suitable scaffold for lead optimization strategies., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2020
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31. Acridine Photocatalysis: Insights into the Mechanism and Development of a Dual-Catalytic Direct Decarboxylative Conjugate Addition.
- Author
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Dang HT, Haug GC, Nguyen VT, Vuong NTH, Nguyen VD, Arman HD, and Larionov OV
- Abstract
Conjugate addition is one of the most synthetically useful carbon‒carbon bond-forming reactions, however, reactive carbon nucleophiles are typically required to effect the addition. Radical conjugate addition provides an avenue for replacing reactive nucleophiles with convenient radical precursors. Carboxylic acids can serve as simple and stable radical precursors by way of decarboxylation, but activation to reactive esters is typically necessary to facilitate the challenging decarboxylation. Here, we report a direct, dual-catalytic decarboxylative radical conjugate addition of a wide range of carboxylic acids that does not require acid preactivation and is enabled by the visible light-driven acridine photocatalysis interfaced with an efficient copper catalytic cycle. Mechanistic and computational studies provide insights into the roles of the ligands and metal species in the dual catalytic process and the photocatalytic activity of substituted acridines., Competing Interests: ASSOCIATED CONTENT The authors declare no competing financial interest.
- Published
- 2020
- Full Text
- View/download PDF
32. Synthesis of amino-diamondoid pharmacophores via photocatalytic C-H aminoalkylation.
- Author
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Weigel WK 3rd, Dang HT, Yang HB, and Martin DBC
- Subjects
- Alkylation, Amino Acids chemistry, Catalysis, Imines chemistry, Stereoisomerism, Amines chemistry, Carbon chemistry, Hydrogen chemistry, Light
- Abstract
We report a direct C-H aminoalkylation reaction using two light-activated H-atom transfer catalyst systems that enable the introduction of protected amines to native adamantane scaffolds with C-C bond formation. The scope of adamantane and imine reaction partners is broad and deprotection provides versatile amine and amino acid building blocks. Using readily available chiral imines, the enantioselective synthesis of the saxagliptin core and rimantadine derivatives is also described.
- Published
- 2020
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- View/download PDF
33. Deoxygenative α-alkylation and α-arylation of 1,2-dicarbonyls.
- Author
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Jin S, Dang HT, Haug GC, Nguyen VD, Arman HD, and Larionov OV
- Abstract
Construction of C-C bonds at the α-carbon is a challenging but synthetically indispensable approach to α-branched carbonyl motifs that are widely represented among drugs, natural products, and synthetic intermediates. Here, we describe a simple approach to generation of boron enolates in the absence of strong bases that allows for introduction of both α-alkyl and α-aryl groups in a reaction of readily accessible 1,2-dicarbonyls and organoboranes. Obviation of unselective, strongly basic and nucleophilic reagents permits carrying out the reaction in the presence of electrophiles that intercept the intermediate boron enolates, resulting in two new α-C-C bonds in a tricomponent process., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)
- Published
- 2020
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- View/download PDF
34. Visible-Light-Enabled Direct Decarboxylative N-Alkylation.
- Author
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Nguyen VT, Nguyen VD, Haug GC, Vuong NTH, Dang HT, Arman HD, and Larionov OV
- Subjects
- Acridines chemistry, Alkylation, Aniline Compounds chemistry, Catalysis, Oxidation-Reduction, Amines chemistry, Heterocyclic Compounds chemistry
- Abstract
The development of efficient and selective C-N bond-forming reactions from abundant feedstock chemicals remains a central theme in organic chemistry owing to the key roles of amines in synthesis, drug discovery, and materials science. Herein, we present a dual catalytic system for the N-alkylation of diverse aromatic carbocyclic and heterocyclic amines directly with carboxylic acids, by-passing their preactivation as redox-active esters. The reaction, which is enabled by visible-light-driven, acridine-catalyzed decarboxylation, provides access to N-alkylated secondary and tertiary anilines and N-heterocycles. Additional examples, including double alkylation, the installation of metabolically robust deuterated methyl groups, and tandem ring formation, further demonstrate the potential of the direct decarboxylative alkylation (DDA) reaction., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2020
- Full Text
- View/download PDF
35. Visible Light-Induced Borylation of C-O, C-N, and C-X Bonds.
- Author
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Jin S, Dang HT, Haug GC, He R, Nguyen VD, Nguyen VT, Arman HD, Schanze KS, and Larionov OV
- Subjects
- Catalysis, Boronic Acids chemistry, Carbon chemistry, Light, Nitrogen chemistry, Oxygen chemistry
- Abstract
Boronic acids are centrally important functional motifs and synthetic precursors. Visible light-induced borylation may provide access to structurally diverse boronates, but a broadly efficient photocatalytic borylation method that can effect borylation of a wide range of substrates, including strong C-O bonds, remains elusive. Herein, we report a general, metal-free visible light-induced photocatalytic borylation platform that enables borylation of electron-rich derivatives of phenols and anilines, chloroarenes, as well as other haloarenes. The reaction exhibits excellent functional group tolerance, as demonstrated by the borylation of a range of structurally complex substrates. Remarkably, the reaction is catalyzed by phenothiazine, a simple organic photocatalyst with MW < 200 that mediates the previously unachievable visible light-induced single electron reduction of phenol derivatives with reduction potentials as negative as approximately - 3 V versus SCE by a proton-coupled electron transfer mechanism. Mechanistic studies point to the crucial role of the photocatalyst-base interaction.
- Published
- 2020
- Full Text
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36. Alkene Synthesis by Photocatalytic Chemoenzymatically Compatible Dehydrodecarboxylation of Carboxylic Acids and Biomass.
- Author
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Nguyen VT, Nguyen VD, Haug GC, Dang HT, Jin S, Li Z, Flores-Hansen C, Benavides BS, Arman HD, and Larionov OV
- Abstract
Direct conversion of renewable biomass and bioderived chemicals to valuable synthetic intermediates for organic synthesis and materials science applications by means of mild and chemoselective catalytic methods has largely remained elusive. Development of artificial catalytic systems that are compatible with enzymatic reactions provides a synergistic solution to this enduring challenge by leveraging previously unachievable reactivity and selectivity modes. We report herein a dual catalytic dehydrodecarboxylation reaction that is enabled by a crossover of the photoinduced acridine-catalyzed O-H hydrogen atom transfer (HAT) and cobaloxime-catalyzed C-H-HAT processes. The reaction produces a variety of alkenes from readily available carboxylic acids. The reaction can be embedded in a scalable triple-catalytic cooperative chemoenzymatic lipase-acridine-cobaloxime process that allows for direct conversion of plant oils and biomass to long-chain terminal alkenes, precursors to bioderived polymers., Competing Interests: The authors declare the following competing financial interest(s): The UTSA has filed a provisional patent application for the process described in this publication.
- Published
- 2019
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37. A Laboratory-Scale Study of the Applicability of a Halophilic Sediment Bioelectrochemical System for in situ Reclamation of Water and Sediment in Brackish Aquaculture Ponds: Establishment, Bacterial Community and Performance Evaluation.
- Author
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Pham HT, Tran HT, Vu LT, Dang HT, Nguyen TTT, Dang THT, Nguyen MTT, Nguyen HQ, and Kim BH
- Subjects
- Animal Feed, Animals, Bacteria classification, Bacteria genetics, Bacteria isolation & purification, Biodegradation, Environmental, Bioelectric Energy Sources, Biological Oxygen Demand Analysis, Electricity, Geologic Sediments chemistry, Geologic Sediments microbiology, Nitrogen analysis, Ponds chemistry, Aquaculture, Microbiota genetics, Ponds microbiology, Waste Disposal, Fluid methods, Water Pollutants metabolism
- Abstract
In this study, we investigated the potential of using sediment bioelectrochemical systems (SBESs) for in situ treatment of the water and sediment in brackish aquaculture ponds polluted with uneaten feed. An SBES integrated into a laboratory-scale tank simulating a brackish aquaculture pond was established. This test tank and the control (not containing the SBES) were fed with shrimp feed in a scheme that mimics a situation where 50% of feed is uneaten. After the SBES was inoculated with microbial sources from actual shrimp pond sediments, electricity generation was well observed from the first experimental week, indicating successful enrichment of electrochemically active bacteria in the test tank sediment. The electricity generation became steady after 3 weeks of operation, with an average current density of 2.3 mA/m
2 anode surface and an average power density of 0.05 mW/m2 anode surface. The SBES removed 20-30% more COD of the tank water, compared to the control. After 1 year, the SBES also reduced the amount of sediment in the tank by 40% and thus could remove approximately 40% more COD and approximately 52% more nitrogen from the sediment, compared to the control. Insignificant amounts of nitrite and nitrate were detected, suggesting complete removal of nitrogen by the system. PCR-DGGE-based analyses revealed the dominant presence of Methylophilus rhizosphaerae , Desulfatitalea tepidiphila and Thiothrix eikelboomii , which have not been found in bioelectrochemical systems before, in the bacterial community in the sediment of the SBES-containing tank. The results of this research demonstrate the potential application of SBESs in helping to reduce water pollution threats, fish and shrimp disease risks, and thus farmers' losses.- Published
- 2019
- Full Text
- View/download PDF
38. Highly Stereoselective and Catalytic Desulfitative C-O and C-I Dienylation with Sulfolenes: the Importance of Basic Additives.
- Author
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Dang HT, Nguyen VD, Pham HH, Arman HD, and Larionov OV
- Abstract
Conjugated dienes and polyenes are central structural motifs of natural products, and key synthetic intermediates in organic synthesis and materials science. We describe herein a palladium-catalyzed dienylation of aryl, heteroaryl, and vinyl triflates, nonaflates and iodides that were previously identified as recalcitrant substrates for the sulfolene-mediated catalytic dienylation. The method has now been successfully expanded to C-O and C-I dienylation, demonstrating broad scope with respect to sulfonates, iodides and sulfolenes. The reactions proceed with high regio- and stereoselectivity, and efficiency that are strongly influenced by basic additives, whose influence on the reaction performance was systematically studied.
- Published
- 2019
- Full Text
- View/download PDF
39. No apparent fitness costs associated with phytoene desaturase mutations conferred resistance to diflufenican and picolinafen in oriental mustard (Sisymbrium orientale L.).
- Author
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Dang HT, Long W, Malone JM, Preston C, and Gill G
- Subjects
- Herbicide Resistance, Mustard Plant genetics, Mutation genetics, Niacinamide pharmacology, Oxidoreductases metabolism, Plant Proteins genetics, Plant Proteins metabolism, Herbicides pharmacology, Mustard Plant drug effects, Mustard Plant metabolism, Niacinamide analogs & derivatives, Oxidoreductases genetics
- Abstract
Two mutations Leu498 and Glu425 in the PDS gene were identified as the main cause conferring resistance to diflufenican and picolinafen in two oriental mustard populations P3 and P40. As mutations are suspected to affect fitness, this study was designed to test this hypothesis using the F
2 of two crosses P3.2 (P3♂ × S♀) and P40.5 (P40♂ × S♀) of oriental mustard. The F2 plants, which segregated for target-site point mutations of PDS gene (Leu498 and Glu425) grown in monoculture and under competition with wheat in pot-trials and evaluated for growth and fecundity. All F2 individuals were genotyped by using Cleaved Amplified Polymorphic Sequence (CAPS) technique. Regression analysis showed no fitness cost in the resistant plants because no significant difference was identified in seed and biomass production within RR, RS and SS individuals. The absence of measurable negative effects on fitness associated mutations suggests that the frequency of the PDS resistance alleles will not decline in the absence of selection pressure of PDS-inhibitors., (Copyright © 2019. Published by Elsevier Inc.)- Published
- 2019
- Full Text
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40. Organoboron chemistry comes to light: recent advances in photoinduced synthetic approaches to organoboron compounds.
- Author
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Nguyen VD, Nguyen VT, Jin S, Dang HT, and Larionov OV
- Abstract
Photoinduced synthetic approaches to organoboron compounds have attracted significant attention in the recent years. Photochemical activation of organic molecules enables generation of reactive intermediates from a variety of precursors, resulting in borylation methods with improved and broader substrate scopes. The review summarizes recent developments in the area of photoinduced reactions of organoboron compounds with an emphasis on borylation of haloarenes, amine derivatives, and redox-active esters of carboxylic acids, as well as photoinduced rearrangements of organoboron compounds and photoinduced synthesis of organoboron compounds from alkenes and alkynes.
- Published
- 2019
- Full Text
- View/download PDF
41. Cross-resistance to diflufenican and picolinafen and its inheritance in oriental mustard (Sisymbrium orientale L.).
- Author
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Dang HT, Malone JM, Gill G, and Preston C
- Subjects
- Amino Acid Sequence, Base Sequence, Brassicaceae genetics, Brassicaceae physiology, Mutation, Niacinamide pharmacology, Plant Proteins metabolism, Sequence Alignment, Brassicaceae drug effects, Herbicide Resistance genetics, Herbicides pharmacology, Heredity, Niacinamide analogs & derivatives, Oxidoreductases genetics, Plant Proteins genetics
- Abstract
Background: An oriental mustard population (P40) was identified as resistant to diflufenican by screening at the field rate. As diflufenican and picolinafen both target phytoene desaturase (PDS), cross-resistance to picolinafen was suspected. The mechanism of resistance and its inheritance to diflufenican and picolinafen were investigated., Results: At the lethal dose (LD
50 ) level, population P40 was 237-fold more resistant to diflufenican and seven-fold more resistant to picolinafen compared to two susceptible populations. Population P40 also had a significantly higher resistance to diflufenican (237-fold) than a previously described P3 population (143-fold). In addition to the Leu-498-Val mutation in PDS identified in all individuals of the P3 and P40 populations, a Glu-425-Asp mutation was also found in P40. Neither mutation was detected in any individuals of the susceptible population. As the segregation of phenotype and genotype of the F2 individuals fitted the model for a single dominant allele, resistance to both diflufenican and picolinafen is likely encoded on the nuclear genome and is dominant., Conclusion: Resistance to diflufenican and picolinafen in the P40 population is likely conferred by Leu-498-Val and Glu-425-Asp mutations in the PDS gene. Inheritance of resistance to these herbicides is managed by a single dominant gene. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)- Published
- 2019
- Full Text
- View/download PDF
42. Use of Potentially Inappropriate Medications in People With Dementia in Vietnam and Its Associated Factors.
- Author
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Nguyen TA, Pham T, Vu HTT, Nguyen TX, Vu TT, Nguyen BTT, Nguyen NQ, Nguyen BT, Nguyen BT, Nguyen TN, Phan SV, Nguyen AT, Pham TL, Dang HT, Kalisch-Ellett L, Gillam M, Pratt N, Qiang S, Wang H, Kanjanarach T, Hassali MAA, Babar ZU, Razak AA, Chinwong D, and Roughead EE
- Subjects
- Aged, Aged, 80 and over, Antipsychotic Agents adverse effects, Cholinergic Antagonists adverse effects, Cholinesterase Inhibitors adverse effects, Cognition drug effects, Female, Humans, Male, Vietnam epidemiology, Antipsychotic Agents administration & dosage, Cholinergic Antagonists administration & dosage, Cholinesterase Inhibitors administration & dosage, Dementia epidemiology, Potentially Inappropriate Medication List standards
- Abstract
This study examined the use of potentially inappropriate medicines that may affect cognition (PIMcog) in people with dementia and its associated factors. Medical records of all outpatients with dementia attending a tertiary hospital in Vietnam between January 1, 2015, and December 31, 2016, were examined. Medicine use was assessed against a list of PIMcog. Variables associated with having a PIMcog were assessed using a multiple logistic regression. Of the 128 patients, 41% used a PIMcog, 39.1% used cholinesterase inhibitors (CEIs) concomitantly with anticholinergics, and 18% used antipsychotics. The number of hospital visits (adjusted odds ratio [OR]: 1.08; 95% confidence interval [CI]: 1.02-1.16) and number of treating specialists (adjusted OR: 0.61; 95% CI: 0.45-0.83) were associated with PIMcog use. This study highlights a high-level use of medicines that can further impair cognition or reduce the effectiveness of CEIs in people with dementia. Efforts to improve quality use of medicines for this population are warranted.
- Published
- 2018
- Full Text
- View/download PDF
43. Highly Regio- and Stereoselective Catalytic Synthesis of Conjugated Dienes and Polyenes.
- Author
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Nguyen VT, Dang HT, Pham HH, Nguyen VD, Flores-Hansen C, Arman HD, and Larionov OV
- Subjects
- Alkadienes chemistry, Catalysis, Chemistry Techniques, Synthetic methods, Palladium chemistry, Polyenes chemistry, Stereoisomerism, Alkadienes chemical synthesis, Polyenes chemical synthesis
- Abstract
Conjugated dienes and polyenes are typically synthesized by sequential introduction of C═C bonds. Here, we report a practical and scalable, catalytic dienylation that is highly regio- and stereoselective for both C═C bonds. The reaction is enabled by a stereoselective palladium-catalyzed cross-coupling that is preceded by a regioselective base-induced ring opening of readily available sulfolenes. The dienylation reaction is particularly useful for the synthesis of synthetically challenging dienes containing cis double bonds. We also show that the reaction can serve as a synthetic platform for the construction of conjugated polyenes.
- Published
- 2018
- Full Text
- View/download PDF
44. The mechanism of diflufenican resistance and its inheritance in oriental mustard (Sisymbrium orientale L.) from Australia.
- Author
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Dang HT, Malone JM, Boutsalis P, Gill G, and Preston C
- Subjects
- Amino Acid Sequence, Base Sequence, Brassicaceae drug effects, Niacinamide pharmacology, Oxidoreductases chemistry, Oxidoreductases metabolism, Sequence Alignment, Victoria, Brassicaceae genetics, Herbicide Resistance genetics, Herbicides pharmacology, Heredity, Niacinamide analogs & derivatives, Oxidoreductases genetics
- Abstract
Background: An oriental mustard population (P3) collected near Quambatook, Victoria was identified as being resistant to diflufenican by screening with the field rate (200 g a.i. ha
-1 ) of the herbicide. The mechanism(s) of diflufenican resistance and its inheritance in this population were therefore investigated., Results: Dose-response experiments confirmed that population P3 was 140-fold more resistant to diflufenican than susceptible populations, as determined by the comparison of 50% lethal (LD50 ) values. The phytoene desaturase (PDS) gene from five individuals each of the S1 [susceptible (S)] and P3 [resistant (R)] populations was sequenced, and a substitution of valine for leucine at position 526 (Leu-526-Val) was detected in all five individuals of P3, but not in the S1 population. Inheritance studies showed that diflufenican resistance is encoded in the nuclear genome and is dominant, as the response to diflufenican at 200 g a.i. ha-1 of F1 families was equivalent to that of the resistant biotype. The segregation of F2 phenotypes fitted a 3:1 inheritance model. Segregation of 42 F2 individuals by genotype sequencing fitted a 1:2:1 (ss:Rs:RR) ratio., Conclusion: Resistance to diflufenican in oriental mustard is conferred by the Leu-526-Val mutation in the PDS gene. Inheritance of resistance is managed by a single gene with high levels of dominance. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)- Published
- 2018
- Full Text
- View/download PDF
45. Reduced translocation in 2,4-D-resistant oriental mustard populations (Sisymbrium orientale L.) from Australia.
- Author
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Dang HT, Malone JM, Boutsalis P, Krishnan M, Gill G, and Preston C
- Subjects
- Brassicaceae genetics, Heredity, Mutation, Plant Leaves metabolism, Plant Proteins genetics, Plant Proteins metabolism, South Australia, 2,4-Dichlorophenoxyacetic Acid pharmacology, Brassicaceae drug effects, Herbicide Resistance genetics, Herbicides pharmacology
- Abstract
Background: Two oriental mustard populations (P2 and P13) collected from Port Broughton, South Australia were identified as resistant to 2,4-D. The level of resistance, mechanism and the mode of inheritance for 2,4-D resistance in these populations were investigated., Results: Populations P2 and P13 were confirmed to be resistant to 2,4-D at the field rate (600 g a.e. ha
-1 ). P2 and P13 were 81- and 67-fold more resistant than the susceptible populations (S1 and S2) at the dose required for 50% mortality (LD50 ), respectively. No predicted amino acid modification was detected in sequences of potential target-site genes (ABP, TIR1 and AFB5). Resistant populations had reduced 2,4-D translocation compared with the susceptible populations, with 77% of [14 C]2,4-D retained in the treated leaf versus 32% at 72 h after treatment. Resistance to 2,4-D is encoded on the nuclear genome and is dominant, as the response to 2,4-D of all F2 individuals were similar to the resistant biotypes. The segregation of F2 phenotypes fitted a 3: 1 (R: S) inheritance model., Conclusion: Resistance to 2,4-D in oriental mustard is likely due to reduced translocation of 2,4-D out of the treated leaf. Inheritance of 2,4-D resistance is conferred by a single gene with a high level of dominance. © 2017 Society of Chemical Industry., (© 2017 Society of Chemical Industry.)- Published
- 2018
- Full Text
- View/download PDF
46. Efficient synthesis of 3-sulfolenes from allylic alcohols and 1,3-dienes enabled by sodium metabisulfite as a sulfur dioxide equivalent.
- Author
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Dang HT, Nguyen VT, Nguyen VD, Arman HD, and Larionov OV
- Subjects
- Chemistry Techniques, Synthetic, Alkenes chemistry, Propanols chemistry, Sulfites chemistry, Sulfur Dioxide chemistry, Thiophenes chemical synthesis, Thiophenes chemistry
- Abstract
We present herein an efficient and practical method for a gram scale synthesis of 3-sulfolenes using sodium metabisulfite as a safe, inexpensive, and easy to handle sulfur dioxide equivalent. Diversely-substituted 3-sulfolenes can be prepared by reacting a variety of 1,3-dienes or allylic alcohols with sodium metabisulfite in aqueous hexafluoroisopropanol (HFIP) or in aqueous methanol in the presence of potassium hydrogen sulfate. Advantageously, the method enables conversion of allylic alcohols directly to 3-sulfolenes, bypassing intermediate 1,3-dienes.
- Published
- 2018
- Full Text
- View/download PDF
47. Antiviral Activity of Novel Quinoline Derivatives against Dengue Virus Serotype 2.
- Author
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de la Guardia C, Stephens DE, Dang HT, Quijada M, Larionov OV, and Lleonart R
- Subjects
- Animals, Antiviral Agents chemistry, Chlorocebus aethiops, Dose-Response Relationship, Drug, Gene Expression Regulation, Viral drug effects, Molecular Structure, Quinolines chemistry, Quinolines pharmacology, Serogroup, Vero Cells, Antiviral Agents chemical synthesis, Dengue Virus metabolism, Quinolines chemical synthesis, Viral Envelope Proteins metabolism
- Abstract
Dengue virus causes dengue fever, a debilitating disease with an increasing incidence in many tropical and subtropical territories. So far, there are no effective antivirals licensed to treat this virus. Here we describe the synthesis and antiviral activity evaluation of two compounds based on the quinoline scaffold, which has shown potential for the development of molecules with various biological activities. Two of the tested compounds showed dose-dependent inhibition of dengue virus serotype 2 in the low and sub micromolar range. The compounds 1 and 2 were also able to impair the accumulation of the viral envelope glycoprotein in infected cells, while showing no sign of direct virucidal activity and acting possibly through a mechanism involving the early stages of the infection. The results are congruent with previously reported data showing the potential of quinoline derivatives as a promising scaffold for the development of new antivirals against this important virus., Competing Interests: The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
- Published
- 2018
- Full Text
- View/download PDF
48. Photoinduced Carboborative Ring Contraction Enables Regio- and Stereoselective Synthesis of Multiply Substituted Five-Membered Carbocycles and Heterocycles.
- Author
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Jin S, Nguyen VT, Dang HT, Nguyen DP, Arman HD, and Larionov OV
- Subjects
- Biological Products chemistry, Boranes chemistry, Heterocyclic Compounds chemistry, Models, Molecular, Photochemical Processes, Stereoisomerism, Steroids chemistry, Biological Products chemical synthesis, Boranes chemical synthesis, Heterocyclic Compounds chemical synthesis, Steroids chemical synthesis
- Abstract
We report herein a photoinduced carboborative ring contraction of monounsaturated six-membered carbocycles and heterocycles. The reaction produces substituted five-membered ring systems stereoselectively and on preparative scales. The products feature multiple stereocenters, including contiguous quaternary carbons. We show that the reaction can serve as a synthetic platform for ring system alteration of natural products. The reaction can also be used in natural product synthesis. A concise total synthesis of artalbic acid has been enabled by a sequence of photoinduced carboborative ring contraction, Rauhut-Currier reaction, and nitrilase-catalyzed hydrolysis. The synthetic utility of the reaction has been further demonstrated by converting the intermediate organoboranes to alcohols, amines, and alkenes.
- Published
- 2017
- Full Text
- View/download PDF
49. Characterization of LuxI and LuxR Protein Homologs of N-Acylhomoserine Lactone-Dependent Quorum Sensing System in Pseudoalteromonas sp. 520P1.
- Author
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Dang HT, Komatsu S, Masuda H, and Enomoto K
- Subjects
- Acyl-Butyrolactones metabolism, Amino Acid Sequence, Cloning, Molecular, Escherichia coli genetics, Escherichia coli metabolism, Genome, Bacterial, Phylogeny, Pseudoalteromonas classification, Pseudoalteromonas enzymology, Recombinant Proteins genetics, Recombinant Proteins metabolism, Sequence Alignment, Sequence Homology, Amino Acid, Bacterial Proteins genetics, Gene Expression Regulation, Bacterial, Ligases genetics, Pseudoalteromonas genetics, Quorum Sensing genetics, Repressor Proteins genetics, Trans-Activators genetics, Transcription Factors genetics
- Abstract
Pseudoalteromonas sp. 520P1 (hereafter referred to as strain 520P1) produces N-acylhomoserine lactones (AHLs), which serve as signaling molecules in Gram-negative bacterial quorum sensing. In a previous genomic analysis of the 5.25-Mb genome of strain 520P1, we detected the presence of at least one homolog of the AHL synthase gene (luxI) and five homologs of the transcriptional regulator protein gene (luxR). The LuxI homolog of strain 520P1 (PalI) contained the conserved amino acid motifs shared by all the LuxI family proteins of the different species examined here. The palI gene expressed in Escherichia coli produced two types of AHLs. In the thin-layer chromatography analysis, these AHLs showed identical mobility to the AHLs produced by strain 520P1. The five LuxR homologs of strain 520P1 (PalR1-PalR5) shared only 17-34% amino acid sequence identity, although higher identities were observed in the C-terminal DNA-binding domain. Among the five PalRs, only PalR5 displayed close homology with LuxR family proteins from other Pseudoalteromonas strains. Notably, the palR3 and palI genes were located close together and only 1021 bases apart in the genome. No cognate luxI homolog associated with the four other palR genes was detected. These characteristics of PalI and the PalRs suggest that AHL autoinducers generated by the PalI enzyme might regulate cellular metabolism in cooperation with five transcriptional regulator PalRs, each of which is presumed to play a distinctive role in bacterial signaling.
- Published
- 2017
- Full Text
- View/download PDF
50. Band Structure and Terahertz Optical Conductivity of Transition Metal Oxides: Theory and Application to CaRuO(3).
- Author
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Dang HT, Mravlje J, Georges A, and Millis AJ
- Abstract
Density functional plus dynamical mean field calculations are used to show that in transition metal oxides, rotational and tilting (GdFeO(3)-type) distortions of the ideal cubic perovskite structure produce a multiplicity of low-energy optical transitions which affect the conductivity down to frequencies of the order of 1 or 2 mV (terahertz regime), mimicking non-Fermi-liquid effects even in systems with a strictly Fermi-liquid self-energy. For CaRuO(3), a material whose measured electromagnetic response in the terahertz frequency regime has been interpreted as evidence for non-Fermi-liquid physics, the combination of these band structure effects and a renormalized Fermi-liquid self-energy accounts for the low frequency optical response which had previously been regarded as a signature of exotic physics. Signatures of deviations from Fermi-liquid behavior at higher frequencies (∼100 meV) are discussed.
- Published
- 2015
- Full Text
- View/download PDF
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