Van Nguyen - Academia.edu (original) (raw)
Papers by Van Nguyen
Sustainability
In this research article, we aim to study the proposed role of human–machine interactive (HMI) te... more In this research article, we aim to study the proposed role of human–machine interactive (HMI) technologies, including both artificial intelligence (AI) and virtual reality (VR)-enabled applications, for the post-COVID-19 revival of the already depleted tourism industry in Vietnam’s major tourist destination and business hub of Ho Chi Minh City. The researchers aim to gather practical knowledge regarding tourists’ intentions for such service enhancements, which may drive the sector to adopt a better conclusive growth pattern in post-COVID-19 times. In this study, we attempt to focus on travelers who look for paramount safety with the assurance of empathetic, personalized care in post-COVID-19 times. In the current study, the authors employ structural equation modeling to evaluate the intentions of tourists both structurally and empirically for destination tourism with data collected from tourists with previous exposure to various kinds of these devices. The study shows that human–ma...
Antibiotics
In the Mekong Delta of Vietnam, farmers use large quantities of antimicrobials to raise small-sca... more In the Mekong Delta of Vietnam, farmers use large quantities of antimicrobials to raise small-scale chicken flocks, often including active ingredients regarded of “critical importance’” by the World Health Organization. Due to limitations in laboratory capacity, the choice of antimicrobials normally does not follow any empirical criteria of effectiveness. The aim of this study was to highlight non-critically important antimicrobials against which chicken pathogens are likely to be susceptible as a basis for treatment guidelines. Microtiter broth dilution method was performed to determine the minimal inhibitory concentration (MIC) of 12 commonly used antimicrobials for 58 isolates, including Ornithobacterium rhinotracheale (ORT) (n = 22), Gallibacterium anatis (n = 19), and Avibacterium endocarditidis (n = 17). Unfortunately, internationally accepted breakpoints for resistance in these organisms do not exist. We drew tentative epidemiological cut-offs (TECOFFs) for those antimicrobia...
Alkaloids [Working Title]
Zanthoxylum genus (Rutaceae) comprises about 212 species distributed in warm temperature and subt... more Zanthoxylum genus (Rutaceae) comprises about 212 species distributed in warm temperature and subtropical areas in the worldwide. Zanthoxylum species have been used in traditional for the treatment of tooth decay, snakebites, blood circulation problems, stomach problems, inflammation, rheumatic, and parasitic diseases. The chemical investigations of Zanthoxylum have been studied by many scientists over the world. Several classes of compounds have been isolated from this genus such as alkaloids, coumarins, and monoterpenes. Of these, alkaloids are the main components and play an important role in Zanthoxylum species. Alkaloids have been shown the potential promise about biological activities: cytotoxic, antimalarial, leishmanicidal, anti-inflammatory, analgesic, antiviral, and antibacterial activities. This chapter will focus on the structure elucidation and pharmacological activities of alkaloids from Zanthoxylum species. In addition, the absolute configuration of some alkaloids from Zanthoxylum genus will be also discussed.
PloS one, 2018
With less than 3200 wild tigers in 2010, the heads of 13 tiger-range countries committed to doubl... more With less than 3200 wild tigers in 2010, the heads of 13 tiger-range countries committed to doubling the global population of wild tigers by 2022. This goal represents the highest level of ambition and commitment required to turn the tide for tigers in the wild. Yet, ensuring efficient and targeted implementation of conservation actions alongside systematic monitoring of progress towards this goal requires that we set site-specific recovery targets and timelines that are ecologically realistic. In this study, we assess the recovery potential of 18 sites identified under WWF's Tigers Alive Initiative. We delineated recovery systems comprising a source, recovery site, and support region, which need to be managed synergistically to meet these targets. By using the best available data on tiger and prey numbers, and adapting existing species recovery frameworks, we show that these sites, which currently support 165 (118-277) tigers, have the potential to harbour 585 (454-739) individ...
Western Pacific surveillance and response journal : WPSAR
The purpose of this survey was to estimate the prevalence of viral load (VL) suppression and emer... more The purpose of this survey was to estimate the prevalence of viral load (VL) suppression and emergence of HIV drug resistance (HIVDR) among individuals receiving antiretroviral therapy (ART) for 36 months or longer in Viet Nam using a nationally representative sampling method. The survey was conducted between May and August 2014 using a two-stage cluster design. Sixteen ART clinics were selected using probability proportional to proxy size sampling, and patients receiving ART for at least 36 months were consecutively enrolled. Epidemiological information and blood specimens were collected for HIV-1 VL and HIVDR testing; HIVDR was defined by the Stanford University HIVDR algorithm. Overall, 365 eligible individuals were recruited with a mean age of 38.2 years; 68.4% were men. The mean time on ART was 75.5 months (95% confidence interval [CI]: 69.0-81.9 months), and 93.7% of the patients were receiving non-nucleoside reverse transcriptase inhibitor-based regimens. Of the 365 individua...
International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases, Jan 23, 2015
Previous studies indicate a high burden of diarrhoeal disease in Vietnamese children, however lon... more Previous studies indicate a high burden of diarrhoeal disease in Vietnamese children, however longitudinal community-based data on burden and aetiology are limited. We present findings from a large, prospective cohort study of diarrhoeal disease in infants in southern Vietnam. Infants were enrolled at birth in urban Ho Chi Minh City and a semi-rural district in southern Vietnam, and followed for 12 months (n=6,706). Diarrhoeal illness episodes were identified through clinic-based passive surveillance, hospital admissions and self-reports. The minimum incidence of diarrhoeal illness in the first year of life was 271/1,000 infant-years of observation for the whole cohort. Rotavirus was the most commonly detected pathogen (50% of positive samples), followed by norovirus (24%), Campylobacter (20%), Salmonella (18%) and Shigella (16%). Repeat infections were identified in 9% of infants infected with rotavirus, norovirus, Shigella or Campylobacter, and 13% of those with Salmonella infecti...
Archives of Pharmacal Research, 2015
One new oleanane triterpene glycoside, ardinsuloside (1), and twelve known compounds, demethoxybe... more One new oleanane triterpene glycoside, ardinsuloside (1), and twelve known compounds, demethoxybergenin (2), norbergenin (3), bergenin (4), 4-O-galloylbergenin (5), quercitrin (6), myricitrin (7), myricetin…
Proceedings of the Second Symposium on Information and Communication Technology - SoICT '11, 2011
Abstract Routing holes in wireless sensor networks (WSN) do occur due to several reasons, includi... more Abstract Routing holes in wireless sensor networks (WSN) do occur due to several reasons, including cases caused by natural obstacles or disaster suffered areas. Computing the exact boundary of a hole is possible [5], but can be impractical with large holes. In this paper, we ...
New Forests, 2011
Abstract The population changes of early successional forest species, Wendlandia paniculata, Schi... more Abstract The population changes of early successional forest species, Wendlandia paniculata, Schima wallichii, Camellia tsaii, and Lithocarpus ducampii, were described and analyzed in a chronosequence of 130 year-old secondary forests representing regrowth after ...
The Journal of Organic Chemistry, 1992
Page 1. J. Org. Chem. 1992,57,235-241 Synthesis and Reactions of 1,l-Diiododinitroethylene 235 Ku... more Page 1. J. Org. Chem. 1992,57,235-241 Synthesis and Reactions of 1,l-Diiododinitroethylene 235 Kurt Baum,* Sean S. Bigelow, Nghi V. Nguyen, and Thomas G. Archibald Fluorochem., Inc., Azusa, California 91 702 Richard ...
The Journal of Organic Chemistry, 1990
The reactions of selected alkynylcyanoketenes and enynylketenes with alkynes are reported to resu... more The reactions of selected alkynylcyanoketenes and enynylketenes with alkynes are reported to result in unusual rearrangements to variously substituted polycyclic aromatic compounds and/or bicyclo[4.2.0]octatrienones. The mechanisms and synthetic scope of these reactions are discussed.
The Journal of Organic Chemistry, 1992
... 1992,57,3026-3030 Nitration of l,l-Diamino-2,2-dinitroethylenes Kurt Baum* and Nghi V. Nguyen... more ... 1992,57,3026-3030 Nitration of l,l-Diamino-2,2-dinitroethylenes Kurt Baum* and Nghi V. Nguyen Fluorochem, Znc., Azusa, California 91 702 Richard Gilardi, Judith L. Flippen-Anderson, and Clifford George ... 1987, 109, 3529. Dewar, M. J. S.; Ritchie, J. P.; Alster, J. J. Org. Chem. ...
Biochemistry, 1976
The secondary structure of highly purified ovalbumin mRNA was studied by automated thermal denatu... more The secondary structure of highly purified ovalbumin mRNA was studied by automated thermal denaturation techniques and the data were subjected to computer processing. Comparative studies with 20 natural and synthetic model nucleic acids suggested that the secondary structure of ovalbumin mRNA possesses the following features: the extent of base pairing of ovalbumin mRNA is similar to that found in tRNAs or ribosomal RNAs; the secondary structure of ovalbumin mRNA is more thermolabile than any of the model compounds tested, including the copolymer poly(A-U); ovalbumin mRNA does not have extensive G-C rich stems as found in tRNAs or ribosomal RNAs; the base composition of the double-stranded regions reveals 54% G-C residues which was significantly higher than that noted in the whole molecule (approximately 41.5% G-C). The presence of 46% A-U pairs in short stems of about five base pairs would have a very large destabilizing effect on the secondary structure of ovalbumin mRNA. However, at 0.175 M monovalent cations and 36 degrees C most of the secondary structure of ovalbumin mRNA is preserved. These data suggest that the double-stranded regions in ovalbumin mRNA are of sufficient length to provide the necessary stability for maintaining the open loop regions in an appropriate conformation which may be required for the biological function of ovalbumin mRNA. Furthermore, the lability of the double-stranded regions in ovalbumin mRNA may also be important for the biological function of this mRNA.
Biochemistry, 1977
ABSTRACT: The secondary structure of ovalbumin messenger RNA and its complementary cDNA,, transcr... more ABSTRACT: The secondary structure of ovalbumin messenger RNA and its complementary cDNA,, transcript was compared using three independent physical techniques: secondary structure probing with ethidium bromide, thermal denaturation, and circular dichroism. The ...
The use of plastic mulch in agriculture has increased dramatically in the last 10 years throughou... more The use of plastic mulch in agriculture has increased dramatically in the last 10 years throughout the world. This increase is due to benefits such as increase in soil temperature, reduced weed pressure, moisture conservation, reduction of certain insect pests, higher crop yields, and more efficient use of soil nutrients. However, disposing of used plastic films, which cause pollution, has led to development of photodegradable and biodegradable mulches. Here we review the use of plastic mulches in agriculture, with special reference to biodegradable mulches. Major topics discussed are (1) history of plastic mulch and impact on crop yield and pest management, (2) limitations of polyethylene mulches and potential alternatives, (3) biodegradable and photodegradable plastic mulches, (4) field performance of biodegradable mulches, and (5) use of biodegradable plastic mulches in organic production. We found that (1) despite multiple benefits, removal and disposal of conventional polyethylene mulches remains a major agronomic, economic, and environmental constraint; (2) early use of photodegradable plastic mulch during the 1970s and 1980s, wrongly named biodegradable mulch films, discouraged adoption of new biodegradable mulch films because they were too expensive and their breakdown was unpredictable; (3) biodegradable plastic films are converted through microbial activity in the soil to carbon dioxide, water, and natural substances; (4) polymers such as poly(lactic acid), poly(butylene adipatecoterephthalate), poly(ε-caprolactone), and starch-based polymer blends or copolymers can degrade when exposed to bioactive environments such as soil and compost; (5) with truly biodegradable materials obtained from petroleum and natural resources, opportunity for using biodegradable polymers as agricultural mulch films has become more viable; and (6) the source of polymer and additives may limit use of some biodegradable mulches in organic production. More knowledge is needed on the effect of biodegradable mulches on crop growth, microclimate modifications, soil biota, soil fertility, and yields.
Sustainability
In this research article, we aim to study the proposed role of human–machine interactive (HMI) te... more In this research article, we aim to study the proposed role of human–machine interactive (HMI) technologies, including both artificial intelligence (AI) and virtual reality (VR)-enabled applications, for the post-COVID-19 revival of the already depleted tourism industry in Vietnam’s major tourist destination and business hub of Ho Chi Minh City. The researchers aim to gather practical knowledge regarding tourists’ intentions for such service enhancements, which may drive the sector to adopt a better conclusive growth pattern in post-COVID-19 times. In this study, we attempt to focus on travelers who look for paramount safety with the assurance of empathetic, personalized care in post-COVID-19 times. In the current study, the authors employ structural equation modeling to evaluate the intentions of tourists both structurally and empirically for destination tourism with data collected from tourists with previous exposure to various kinds of these devices. The study shows that human–ma...
Antibiotics
In the Mekong Delta of Vietnam, farmers use large quantities of antimicrobials to raise small-sca... more In the Mekong Delta of Vietnam, farmers use large quantities of antimicrobials to raise small-scale chicken flocks, often including active ingredients regarded of “critical importance’” by the World Health Organization. Due to limitations in laboratory capacity, the choice of antimicrobials normally does not follow any empirical criteria of effectiveness. The aim of this study was to highlight non-critically important antimicrobials against which chicken pathogens are likely to be susceptible as a basis for treatment guidelines. Microtiter broth dilution method was performed to determine the minimal inhibitory concentration (MIC) of 12 commonly used antimicrobials for 58 isolates, including Ornithobacterium rhinotracheale (ORT) (n = 22), Gallibacterium anatis (n = 19), and Avibacterium endocarditidis (n = 17). Unfortunately, internationally accepted breakpoints for resistance in these organisms do not exist. We drew tentative epidemiological cut-offs (TECOFFs) for those antimicrobia...
Alkaloids [Working Title]
Zanthoxylum genus (Rutaceae) comprises about 212 species distributed in warm temperature and subt... more Zanthoxylum genus (Rutaceae) comprises about 212 species distributed in warm temperature and subtropical areas in the worldwide. Zanthoxylum species have been used in traditional for the treatment of tooth decay, snakebites, blood circulation problems, stomach problems, inflammation, rheumatic, and parasitic diseases. The chemical investigations of Zanthoxylum have been studied by many scientists over the world. Several classes of compounds have been isolated from this genus such as alkaloids, coumarins, and monoterpenes. Of these, alkaloids are the main components and play an important role in Zanthoxylum species. Alkaloids have been shown the potential promise about biological activities: cytotoxic, antimalarial, leishmanicidal, anti-inflammatory, analgesic, antiviral, and antibacterial activities. This chapter will focus on the structure elucidation and pharmacological activities of alkaloids from Zanthoxylum species. In addition, the absolute configuration of some alkaloids from Zanthoxylum genus will be also discussed.
PloS one, 2018
With less than 3200 wild tigers in 2010, the heads of 13 tiger-range countries committed to doubl... more With less than 3200 wild tigers in 2010, the heads of 13 tiger-range countries committed to doubling the global population of wild tigers by 2022. This goal represents the highest level of ambition and commitment required to turn the tide for tigers in the wild. Yet, ensuring efficient and targeted implementation of conservation actions alongside systematic monitoring of progress towards this goal requires that we set site-specific recovery targets and timelines that are ecologically realistic. In this study, we assess the recovery potential of 18 sites identified under WWF's Tigers Alive Initiative. We delineated recovery systems comprising a source, recovery site, and support region, which need to be managed synergistically to meet these targets. By using the best available data on tiger and prey numbers, and adapting existing species recovery frameworks, we show that these sites, which currently support 165 (118-277) tigers, have the potential to harbour 585 (454-739) individ...
Western Pacific surveillance and response journal : WPSAR
The purpose of this survey was to estimate the prevalence of viral load (VL) suppression and emer... more The purpose of this survey was to estimate the prevalence of viral load (VL) suppression and emergence of HIV drug resistance (HIVDR) among individuals receiving antiretroviral therapy (ART) for 36 months or longer in Viet Nam using a nationally representative sampling method. The survey was conducted between May and August 2014 using a two-stage cluster design. Sixteen ART clinics were selected using probability proportional to proxy size sampling, and patients receiving ART for at least 36 months were consecutively enrolled. Epidemiological information and blood specimens were collected for HIV-1 VL and HIVDR testing; HIVDR was defined by the Stanford University HIVDR algorithm. Overall, 365 eligible individuals were recruited with a mean age of 38.2 years; 68.4% were men. The mean time on ART was 75.5 months (95% confidence interval [CI]: 69.0-81.9 months), and 93.7% of the patients were receiving non-nucleoside reverse transcriptase inhibitor-based regimens. Of the 365 individua...
International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases, Jan 23, 2015
Previous studies indicate a high burden of diarrhoeal disease in Vietnamese children, however lon... more Previous studies indicate a high burden of diarrhoeal disease in Vietnamese children, however longitudinal community-based data on burden and aetiology are limited. We present findings from a large, prospective cohort study of diarrhoeal disease in infants in southern Vietnam. Infants were enrolled at birth in urban Ho Chi Minh City and a semi-rural district in southern Vietnam, and followed for 12 months (n=6,706). Diarrhoeal illness episodes were identified through clinic-based passive surveillance, hospital admissions and self-reports. The minimum incidence of diarrhoeal illness in the first year of life was 271/1,000 infant-years of observation for the whole cohort. Rotavirus was the most commonly detected pathogen (50% of positive samples), followed by norovirus (24%), Campylobacter (20%), Salmonella (18%) and Shigella (16%). Repeat infections were identified in 9% of infants infected with rotavirus, norovirus, Shigella or Campylobacter, and 13% of those with Salmonella infecti...
Archives of Pharmacal Research, 2015
One new oleanane triterpene glycoside, ardinsuloside (1), and twelve known compounds, demethoxybe... more One new oleanane triterpene glycoside, ardinsuloside (1), and twelve known compounds, demethoxybergenin (2), norbergenin (3), bergenin (4), 4-O-galloylbergenin (5), quercitrin (6), myricitrin (7), myricetin…
Proceedings of the Second Symposium on Information and Communication Technology - SoICT '11, 2011
Abstract Routing holes in wireless sensor networks (WSN) do occur due to several reasons, includi... more Abstract Routing holes in wireless sensor networks (WSN) do occur due to several reasons, including cases caused by natural obstacles or disaster suffered areas. Computing the exact boundary of a hole is possible [5], but can be impractical with large holes. In this paper, we ...
New Forests, 2011
Abstract The population changes of early successional forest species, Wendlandia paniculata, Schi... more Abstract The population changes of early successional forest species, Wendlandia paniculata, Schima wallichii, Camellia tsaii, and Lithocarpus ducampii, were described and analyzed in a chronosequence of 130 year-old secondary forests representing regrowth after ...
The Journal of Organic Chemistry, 1992
Page 1. J. Org. Chem. 1992,57,235-241 Synthesis and Reactions of 1,l-Diiododinitroethylene 235 Ku... more Page 1. J. Org. Chem. 1992,57,235-241 Synthesis and Reactions of 1,l-Diiododinitroethylene 235 Kurt Baum,* Sean S. Bigelow, Nghi V. Nguyen, and Thomas G. Archibald Fluorochem., Inc., Azusa, California 91 702 Richard ...
The Journal of Organic Chemistry, 1990
The reactions of selected alkynylcyanoketenes and enynylketenes with alkynes are reported to resu... more The reactions of selected alkynylcyanoketenes and enynylketenes with alkynes are reported to result in unusual rearrangements to variously substituted polycyclic aromatic compounds and/or bicyclo[4.2.0]octatrienones. The mechanisms and synthetic scope of these reactions are discussed.
The Journal of Organic Chemistry, 1992
... 1992,57,3026-3030 Nitration of l,l-Diamino-2,2-dinitroethylenes Kurt Baum* and Nghi V. Nguyen... more ... 1992,57,3026-3030 Nitration of l,l-Diamino-2,2-dinitroethylenes Kurt Baum* and Nghi V. Nguyen Fluorochem, Znc., Azusa, California 91 702 Richard Gilardi, Judith L. Flippen-Anderson, and Clifford George ... 1987, 109, 3529. Dewar, M. J. S.; Ritchie, J. P.; Alster, J. J. Org. Chem. ...
Biochemistry, 1976
The secondary structure of highly purified ovalbumin mRNA was studied by automated thermal denatu... more The secondary structure of highly purified ovalbumin mRNA was studied by automated thermal denaturation techniques and the data were subjected to computer processing. Comparative studies with 20 natural and synthetic model nucleic acids suggested that the secondary structure of ovalbumin mRNA possesses the following features: the extent of base pairing of ovalbumin mRNA is similar to that found in tRNAs or ribosomal RNAs; the secondary structure of ovalbumin mRNA is more thermolabile than any of the model compounds tested, including the copolymer poly(A-U); ovalbumin mRNA does not have extensive G-C rich stems as found in tRNAs or ribosomal RNAs; the base composition of the double-stranded regions reveals 54% G-C residues which was significantly higher than that noted in the whole molecule (approximately 41.5% G-C). The presence of 46% A-U pairs in short stems of about five base pairs would have a very large destabilizing effect on the secondary structure of ovalbumin mRNA. However, at 0.175 M monovalent cations and 36 degrees C most of the secondary structure of ovalbumin mRNA is preserved. These data suggest that the double-stranded regions in ovalbumin mRNA are of sufficient length to provide the necessary stability for maintaining the open loop regions in an appropriate conformation which may be required for the biological function of ovalbumin mRNA. Furthermore, the lability of the double-stranded regions in ovalbumin mRNA may also be important for the biological function of this mRNA.
Biochemistry, 1977
ABSTRACT: The secondary structure of ovalbumin messenger RNA and its complementary cDNA,, transcr... more ABSTRACT: The secondary structure of ovalbumin messenger RNA and its complementary cDNA,, transcript was compared using three independent physical techniques: secondary structure probing with ethidium bromide, thermal denaturation, and circular dichroism. The ...
The use of plastic mulch in agriculture has increased dramatically in the last 10 years throughou... more The use of plastic mulch in agriculture has increased dramatically in the last 10 years throughout the world. This increase is due to benefits such as increase in soil temperature, reduced weed pressure, moisture conservation, reduction of certain insect pests, higher crop yields, and more efficient use of soil nutrients. However, disposing of used plastic films, which cause pollution, has led to development of photodegradable and biodegradable mulches. Here we review the use of plastic mulches in agriculture, with special reference to biodegradable mulches. Major topics discussed are (1) history of plastic mulch and impact on crop yield and pest management, (2) limitations of polyethylene mulches and potential alternatives, (3) biodegradable and photodegradable plastic mulches, (4) field performance of biodegradable mulches, and (5) use of biodegradable plastic mulches in organic production. We found that (1) despite multiple benefits, removal and disposal of conventional polyethylene mulches remains a major agronomic, economic, and environmental constraint; (2) early use of photodegradable plastic mulch during the 1970s and 1980s, wrongly named biodegradable mulch films, discouraged adoption of new biodegradable mulch films because they were too expensive and their breakdown was unpredictable; (3) biodegradable plastic films are converted through microbial activity in the soil to carbon dioxide, water, and natural substances; (4) polymers such as poly(lactic acid), poly(butylene adipatecoterephthalate), poly(ε-caprolactone), and starch-based polymer blends or copolymers can degrade when exposed to bioactive environments such as soil and compost; (5) with truly biodegradable materials obtained from petroleum and natural resources, opportunity for using biodegradable polymers as agricultural mulch films has become more viable; and (6) the source of polymer and additives may limit use of some biodegradable mulches in organic production. More knowledge is needed on the effect of biodegradable mulches on crop growth, microclimate modifications, soil biota, soil fertility, and yields.