The central goal of this study was to create a new diagnostic tool to identify organic chemistry ... more The central goal of this study was to create a new diagnostic tool to identify organic chemistry students’ alternative conceptions related to acid strength. Twenty years of research on secondary and college students’ conceptions about acids and bases has shown that these important concepts are difficult for students to apply to qualitative problem solving. Yet, few published studies document how students’ prior knowledge of acids influences their understanding of acid strength in organic chemistry contexts. We developed a nine-item multiple-tier, multiple-choice concept inventory to identify alternative conceptions that organic chemistry students hold about acid strength, to determine the prevalence of these conceptions, and to determine how strongly these conceptions bias student reasoning. We identified two significant alternative conceptions that organic chemistry students hold about acid strength. Students who answered items incorrectly were more confident about their answers than peers who answered items correctly, suggesting that after one semester of organic chemistry, students do not know what they do not know. Implications for the teaching of acid strength are discussed.
A new class of β-amino alcohol and diamine ligands was prepared from isosorbide as a chiral renew... more A new class of β-amino alcohol and diamine ligands was prepared from isosorbide as a chiral renewable resource. The original wedge-shaped structure of isosorbide offers an interesting chiral pocket to promote the metal-catalyzed enantioselective reduction of ketones by transfer hydrogenation.(3S,3aR,6R,6aR)-6-(Benzyloxy)hexahydrofuro[3,2-b]furan-3-olC13H16O4[α]D25=+109.4 (c 0.83, CHCl3)Source of chirality: isosorbideAbsolute configuration: (3S,3aR,6R,6aR)(3R,3aR,6S,6aS)-3-(Benzyloxy)hexahydrofuro[3,2-b]furan-6-yl benzenesulfonateC19H20O6S[α]D25=+92.7 (c 0.25, CHCl3)Source of chirality: isosorbideAbsolute configuration: (3R,3aR,6S,6aS)2-((3R,3aS,6R,6aR)-3-(Benzyloxy)hexahydrofuro[3,2-b]furan-6-ylamino)ethanolC15H21NO4[α]D25=+123.1 (c 1.1, CHCl3)Source of chirality: isosorbideAbsolute configuration: (3R,3aS,6R,6aR)(S)-2-((3R,3aS,6R,6aR)-3-(Benzyloxy)hexahydrofuro[3,2-b]furan-6-ylamino)-3-methylbutan-1-olC18H27NO4[α]D25=+115.6 (c 1.05, CHCl3)Source of chirality: isosorbide and (S)-2-amino-3-methyl-butan-1-olAbsolute configuration: (S),(3R,3aS,6R,6aR)
The abundance of a preselection of transcripts involved in inflammation, immunosenescence and str... more The abundance of a preselection of transcripts involved in inflammation, immunosenescence and stress response was compared between PBMC of healthy aged donors and aged patients in acute phase of heart failure and at recovery. This study identified 22 transcripts differentially abundant in acute phase of heart failure versus healthy aged subjects. Transcripts involved in inflammation and oxidative stress were more abundant. Those associated with T-cell functions were less abundant. The results were compared to two other major acute geriatric issues: infectious diseases and hip fracture. In acute phase, compared to healthy aged subjects, the abundance of 15/22 transcripts was also altered in both geriatric infectious diseases and hip fracture. Many variations had not vanished at the recovery phase. The abundance of CD28, CD69, LCK, HMOX1, TNFRSF1A transcripts, known to be altered in healthy aged versus healthy young subjects, was further affected in acute phase of the three geriatric diseases considered. The transcript levels of BCL2, CASP8, CCL5, DDIT3, EGR3, IL10RB, IL1R2, SERPINB2 and TIMP1 were affected in all three pathological conditions compared to healthy aged, but not versus healthy young subjects. In conclusion, this work provides critical targets for therapeutic research on geriatric heart failure, infectious diseases and hip fracture.► We identified 22 differentially abundant transcripts in heart failure in old persons. ► The results were compared to infectious diseases and hip fracture. ► Commonalities were found in the gene expression of the acute phase of the 3 diseases. ► We provide potential targets in heart failure, infectious diseases and hip fracture. ► We discuss the results in regard with geriatric frailty.
This paper presents a relatively new method for achieving better welding results of gas metal arc... more This paper presents a relatively new method for achieving better welding results of gas metal arc welding (GMAW) system by using a decentralized control method. The GMAW system is an arc welding process which incorporates the power source of GMAW (PS-GMAW) with the wire feed unit (WFU). In this paper, the GMAW system is considered as two separated subsystems, those are PS-GMAW and the WFU. The mathematical modeling of PS-GMAW and WFU are presented. Based on two subsystems, a sliding mode controller is designed and applied to control the WFU meanwhile a proportional controller is designed and applied to control the PS-GMAW. Furthermore, two decentralized controllers have to be designed to control the welding arc of GMAW, be stable and control the output welding current and welding voltage for tracking the constant setting values accurately during the welding process, respectively. The simulation and experimental results are presented to show the effectiveness of the proposed controllers.
Transactions of The Royal Society of Tropical Medicine and Hygiene, 2007
Real-time PCR diagnosis of malaria has advantages over traditional microscopic methods, especiall... more Real-time PCR diagnosis of malaria has advantages over traditional microscopic methods, especially when parasitaemia is low and when dealing with mixed infections. We have developed a new real-time PCR with specific genes in each Plasmodium species present only in one copy to identify the four pathogenic Plasmodium spp. for humans. The sensitivity was less than 25 parasites/μl. No cross-hybridisation was observed with human DNA or among the four Plasmodium spp. Using LightCycler® PCR and conventional microscopy, we compared the diagnosis of malaria in patients from Vietnam and in returned European travellers with suspicion of malaria. In patients from Vietnam with suspicion of malaria, one mixed infection was observed by PCR only; the remaining data (54 of 55 patients) correlated with microscopy. In 79 patients without symptoms, low parasitaemia was detected in 7 samples by microscopy and in 16 samples by PCR. In returned travellers, PCR results were correlated with microscopy for all four species in 48 of 56 samples. The eight discrepant results were resolved in favour of real-time PCR diagnosis. This new real-time PCR is a rapid, accurate and efficient method for malaria diagnosis in returned travellers as well as for epidemiological studies or antimalarial efficiency trials in the field.
The central goal of this study was to create a new diagnostic tool to identify organic chemistry ... more The central goal of this study was to create a new diagnostic tool to identify organic chemistry students’ alternative conceptions related to acid strength. Twenty years of research on secondary and college students’ conceptions about acids and bases has shown that these important concepts are difficult for students to apply to qualitative problem solving. Yet, few published studies document how students’ prior knowledge of acids influences their understanding of acid strength in organic chemistry contexts. We developed a nine-item multiple-tier, multiple-choice concept inventory to identify alternative conceptions that organic chemistry students hold about acid strength, to determine the prevalence of these conceptions, and to determine how strongly these conceptions bias student reasoning. We identified two significant alternative conceptions that organic chemistry students hold about acid strength. Students who answered items incorrectly were more confident about their answers than peers who answered items correctly, suggesting that after one semester of organic chemistry, students do not know what they do not know. Implications for the teaching of acid strength are discussed.
A new class of β-amino alcohol and diamine ligands was prepared from isosorbide as a chiral renew... more A new class of β-amino alcohol and diamine ligands was prepared from isosorbide as a chiral renewable resource. The original wedge-shaped structure of isosorbide offers an interesting chiral pocket to promote the metal-catalyzed enantioselective reduction of ketones by transfer hydrogenation.(3S,3aR,6R,6aR)-6-(Benzyloxy)hexahydrofuro[3,2-b]furan-3-olC13H16O4[α]D25=+109.4 (c 0.83, CHCl3)Source of chirality: isosorbideAbsolute configuration: (3S,3aR,6R,6aR)(3R,3aR,6S,6aS)-3-(Benzyloxy)hexahydrofuro[3,2-b]furan-6-yl benzenesulfonateC19H20O6S[α]D25=+92.7 (c 0.25, CHCl3)Source of chirality: isosorbideAbsolute configuration: (3R,3aR,6S,6aS)2-((3R,3aS,6R,6aR)-3-(Benzyloxy)hexahydrofuro[3,2-b]furan-6-ylamino)ethanolC15H21NO4[α]D25=+123.1 (c 1.1, CHCl3)Source of chirality: isosorbideAbsolute configuration: (3R,3aS,6R,6aR)(S)-2-((3R,3aS,6R,6aR)-3-(Benzyloxy)hexahydrofuro[3,2-b]furan-6-ylamino)-3-methylbutan-1-olC18H27NO4[α]D25=+115.6 (c 1.05, CHCl3)Source of chirality: isosorbide and (S)-2-amino-3-methyl-butan-1-olAbsolute configuration: (S),(3R,3aS,6R,6aR)
The abundance of a preselection of transcripts involved in inflammation, immunosenescence and str... more The abundance of a preselection of transcripts involved in inflammation, immunosenescence and stress response was compared between PBMC of healthy aged donors and aged patients in acute phase of heart failure and at recovery. This study identified 22 transcripts differentially abundant in acute phase of heart failure versus healthy aged subjects. Transcripts involved in inflammation and oxidative stress were more abundant. Those associated with T-cell functions were less abundant. The results were compared to two other major acute geriatric issues: infectious diseases and hip fracture. In acute phase, compared to healthy aged subjects, the abundance of 15/22 transcripts was also altered in both geriatric infectious diseases and hip fracture. Many variations had not vanished at the recovery phase. The abundance of CD28, CD69, LCK, HMOX1, TNFRSF1A transcripts, known to be altered in healthy aged versus healthy young subjects, was further affected in acute phase of the three geriatric diseases considered. The transcript levels of BCL2, CASP8, CCL5, DDIT3, EGR3, IL10RB, IL1R2, SERPINB2 and TIMP1 were affected in all three pathological conditions compared to healthy aged, but not versus healthy young subjects. In conclusion, this work provides critical targets for therapeutic research on geriatric heart failure, infectious diseases and hip fracture.► We identified 22 differentially abundant transcripts in heart failure in old persons. ► The results were compared to infectious diseases and hip fracture. ► Commonalities were found in the gene expression of the acute phase of the 3 diseases. ► We provide potential targets in heart failure, infectious diseases and hip fracture. ► We discuss the results in regard with geriatric frailty.
This paper presents a relatively new method for achieving better welding results of gas metal arc... more This paper presents a relatively new method for achieving better welding results of gas metal arc welding (GMAW) system by using a decentralized control method. The GMAW system is an arc welding process which incorporates the power source of GMAW (PS-GMAW) with the wire feed unit (WFU). In this paper, the GMAW system is considered as two separated subsystems, those are PS-GMAW and the WFU. The mathematical modeling of PS-GMAW and WFU are presented. Based on two subsystems, a sliding mode controller is designed and applied to control the WFU meanwhile a proportional controller is designed and applied to control the PS-GMAW. Furthermore, two decentralized controllers have to be designed to control the welding arc of GMAW, be stable and control the output welding current and welding voltage for tracking the constant setting values accurately during the welding process, respectively. The simulation and experimental results are presented to show the effectiveness of the proposed controllers.
Transactions of The Royal Society of Tropical Medicine and Hygiene, 2007
Real-time PCR diagnosis of malaria has advantages over traditional microscopic methods, especiall... more Real-time PCR diagnosis of malaria has advantages over traditional microscopic methods, especially when parasitaemia is low and when dealing with mixed infections. We have developed a new real-time PCR with specific genes in each Plasmodium species present only in one copy to identify the four pathogenic Plasmodium spp. for humans. The sensitivity was less than 25 parasites/μl. No cross-hybridisation was observed with human DNA or among the four Plasmodium spp. Using LightCycler® PCR and conventional microscopy, we compared the diagnosis of malaria in patients from Vietnam and in returned European travellers with suspicion of malaria. In patients from Vietnam with suspicion of malaria, one mixed infection was observed by PCR only; the remaining data (54 of 55 patients) correlated with microscopy. In 79 patients without symptoms, low parasitaemia was detected in 7 samples by microscopy and in 16 samples by PCR. In returned travellers, PCR results were correlated with microscopy for all four species in 48 of 56 samples. The eight discrepant results were resolved in favour of real-time PCR diagnosis. This new real-time PCR is a rapid, accurate and efficient method for malaria diagnosis in returned travellers as well as for epidemiological studies or antimalarial efficiency trials in the field.
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