To perform in situ metal speciation measurements, a relatively new technique was used consisting ... more To perform in situ metal speciation measurements, a relatively new technique was used consisting of a double layer probe: the first layer is a polymer gel backed by a second gel layer including an ion exchange resin. However, such a system has not yet been studied ...
In order to get a grasp of the current situation and characteristics of heavy metal pollution in ... more In order to get a grasp of the current situation and characteristics of heavy metal pollution in the river environment of Hanoi City and its surrounding area, river sediment was sampled from the To Lich River (urban river) and the Nhue River (suburban/rural river) for three times during the period of October 2005 to June 2006 and analyzed for heavy
Concentrations of heavy metals in water of the Nhue River (a suburban/rural river) and one of its... more Concentrations of heavy metals in water of the Nhue River (a suburban/rural river) and one of its tributaries, the To Lich River (an urban river), in Hanoi, Vietnam had been monitored, and spatial and seasonal variations in their composition were evaluated by means of principal component analysis and cluster analysis. Heavy metal concentrations in water of the two rivers were generally lower than the surface water quality standard in Vietnam, except for manganese in several sites, although they were higher than the median values in freshwater of the world by 0.42-43 times in Nhue and 0.13-32 times in To Lich. The two multivariate analyses represented that the composition of heavy metals in river water of To Lich was distinctly different from that of Nhue. It was also suggested that metal concentrations and their composition in Nhue river water would be affected by inflowing water of To Lich and wastewater discharged from the up-and middle-stream basin, and that they gradually recovered along the direction of water flow in the downstream area in rainy season.
Journal of Chemical Engineering of Japan, Dec 1, 2012
As an alternative using cyanide chemicals for gold extraction, the application of a cyanogenic ba... more As an alternative using cyanide chemicals for gold extraction, the application of a cyanogenic bacterium viz.
Natural rubber processing wastewater contains high concentrations of organic compounds, nitrogen,... more Natural rubber processing wastewater contains high concentrations of organic compounds, nitrogen, and other contaminants. In this study, a treatment system composed of a baffled reactor (BR), an upflow anaerobic sludge blanket (UASB) reactor, and a downflow hanging sponge (DHS) reactor was used to treat natural rubber processing wastewater in Vietnam. The BR showed good total suspended solids removal of 47.6%, as well as acidification of wastewater. The UASB reactor achieved a high chemical oxygen demand (COD) removal efficiency of 92.7% ± 2.3% and energy recovery in the form of methane with an organic loading rate of 12.2 ± 6.6 kg-COD·m(-3)·day(-1). The DHS reactor showed a high performance in residual organic matter removal from UASB effluent. In total, the system achieved high-level total COD removal of 98.6% ± 1.2% and total suspended solids removal of 98.0% ± 1.4%. Massive parallel 16S rRNA gene sequencing of the retained sludge in the UASB reactor showed the predominant microbial phyla to be Bacteroidetes, Firmicutes, Proteobacteria, WWE1, and Euryarchaeota. Uncultured bacteria belonging to the phylum Bacteroidetes and Phylum WWE1 were predominant in the UASB reactor. This microbial assemblage utilizes the organic compounds contained in natural rubber processing wastewater. In addition, the methane-producing archaea Methanosaeta sp. and Methanolinea sp. were detected.
The present communication deals with the leaching of gold from the printed circuit boards (PCBs) ... more The present communication deals with the leaching of gold from the printed circuit boards (PCBs) of waste mobile phones using an effective and less hazardous system, i.e., a copper-ammonia-thiosulfate solution, as an alternative to the conventional and toxic cyanide leaching of gold. The influence of thiosulfate, ammonia and copper sulfate concentrations on the leaching of gold from PCBs of waste mobile phones was investigated. Gold extraction was found to be enhanced with solutions containing 15-20. mM cupric, 0.1-0.14. M thiosulfate, and 0.2-0.3. M ammonia. Similar trends were obtained for the leaching of gold from two different types of scraps and PCBs of waste mobile phones. From the scrap samples, 98% of the gold was leached out using a solution containing 20. mM copper, 0.12. M thiosulfate and 0.2. M ammonia. Similarly, the leaching of gold from the PCBs samples was also found to be good, but it was lower than that of scrap samples in similar experimental conditions. In this case, only 90% of the gold was leached, even with a contact time of 10. h. The obtained data will be useful for the development of processes for the recycling of gold from waste mobile phones.
We performed whole-exome sequencing of a family with autosomal dominant Dandy-Walker malformation... more We performed whole-exome sequencing of a family with autosomal dominant Dandy-Walker malformation and occipital cephaloceles and detected a mutation in the extracellular matrix (ECM) protein-encoding gene NID1. In a second family, protein interaction network analysis identified a mutation in LAMC1, which encodes a NID1-binding partner. Structural modeling of the NID1-LAMC1 complex demonstrated that each mutation disrupts the interaction. These findings implicate the ECM in the pathogenesis of Dandy-Walker spectrum disorders.
To identify causes of nonsyndromic cleft lip and palate in a Vietnamese population. In this study... more To identify causes of nonsyndromic cleft lip and palate in a Vietnamese population. In this study, 175 families with at least one case of cleft lip and/or palate were studied using the candidate genes TGFA, MSX1, and TGFB3. Transmission distortion for alleles of MSX1 were demonstrated for the whole population and two missense mutations were identified, including one (P147Q) that is found in approximately 2% of the population. The P147Q appears to arise from a founder individual based on shared haplotypes in unrelated families. MSX1 contributes to nonsyndromic clefting in a Vietnamese population, and consistent with other studies, identifiable mutations in this gene cause about 2% of cases of nonsyndromic clefting.
The incidence of induced abortion (IA) is high in Vietnam. The purpose of this study is to find o... more The incidence of induced abortion (IA) is high in Vietnam. The purpose of this study is to find out whether IA increases the risk of secondary tubal infertility. A case-control study was conducted at Tu Du Hospital in Vietnam between June and September 2001. Interviews were completed with 67 tubal infertility cases matched by age and residence to 67 controls. The median age of subjects was 34 years old. Proportion of subjects with history of IA was 50.8% and 44.8% for cases and controls, respectively. IA did not significantly increase the risk of secondary infertility. Age of first sexual intercourse was under 20 years old for 29.9% of cases and 9.1% of controls, and it significantly increased the risk of secondary infertility [odds ratio (OR)=3.80]. This study was unable to identify IA as a risk factor of secondary tubal infertility. However, the increased OR for age at first sexual intercourse may imply that being sexually active at an earlier age increases the risk of getting both sexually transmitted diseases and unwanted pregnancies and in turn, increasing the risk of infertility. It is recommended to provide young women and men with the information about health risks related to sexual activity.
Ho Tay (West Lake) in Hanoi, Vietnam receives wastewater from the city center and the surrounding... more Ho Tay (West Lake) in Hanoi, Vietnam receives wastewater from the city center and the surrounding residential areas, which can cause both eutrophication and enrichment of toxic heavy metals in the lake ecosystem. The aim of this study is to evaluate the recent trends of metal contamination in this lake from their spatial (horizontal and vertical) distributions in the lake sediments. Sediment cores with up to 70 cm in depth were sampled from four locations in the lake and analyzed for heavy metals (Cd, Cr, Cu, Mn, Ni, Pb and Zn) including a metalloid (As) and total organic carbon (TOC). High concentrations of the metals (except for Mn) and TOC have accumulated in sediment at the site where an inlet of sewage from the city center was located nearby. Increasing trends of the metal contents in the sediment profile toward the surface at the sites distant from the sewage inlets imply that the loads of these metals into this lake have been continuously increasing. In addition, Pb isotopic ratios in sediment profile could be used as an indicator of anthropogenic Pb pollution in the lake.
To perform in situ metal speciation measurements, a relatively new technique was used consisting ... more To perform in situ metal speciation measurements, a relatively new technique was used consisting of a double layer probe: the first layer is a polymer gel backed by a second gel layer including an ion exchange resin. However, such a system has not yet been studied ...
In order to get a grasp of the current situation and characteristics of heavy metal pollution in ... more In order to get a grasp of the current situation and characteristics of heavy metal pollution in the river environment of Hanoi City and its surrounding area, river sediment was sampled from the To Lich River (urban river) and the Nhue River (suburban/rural river) for three times during the period of October 2005 to June 2006 and analyzed for heavy
Concentrations of heavy metals in water of the Nhue River (a suburban/rural river) and one of its... more Concentrations of heavy metals in water of the Nhue River (a suburban/rural river) and one of its tributaries, the To Lich River (an urban river), in Hanoi, Vietnam had been monitored, and spatial and seasonal variations in their composition were evaluated by means of principal component analysis and cluster analysis. Heavy metal concentrations in water of the two rivers were generally lower than the surface water quality standard in Vietnam, except for manganese in several sites, although they were higher than the median values in freshwater of the world by 0.42-43 times in Nhue and 0.13-32 times in To Lich. The two multivariate analyses represented that the composition of heavy metals in river water of To Lich was distinctly different from that of Nhue. It was also suggested that metal concentrations and their composition in Nhue river water would be affected by inflowing water of To Lich and wastewater discharged from the up-and middle-stream basin, and that they gradually recovered along the direction of water flow in the downstream area in rainy season.
Journal of Chemical Engineering of Japan, Dec 1, 2012
As an alternative using cyanide chemicals for gold extraction, the application of a cyanogenic ba... more As an alternative using cyanide chemicals for gold extraction, the application of a cyanogenic bacterium viz.
Natural rubber processing wastewater contains high concentrations of organic compounds, nitrogen,... more Natural rubber processing wastewater contains high concentrations of organic compounds, nitrogen, and other contaminants. In this study, a treatment system composed of a baffled reactor (BR), an upflow anaerobic sludge blanket (UASB) reactor, and a downflow hanging sponge (DHS) reactor was used to treat natural rubber processing wastewater in Vietnam. The BR showed good total suspended solids removal of 47.6%, as well as acidification of wastewater. The UASB reactor achieved a high chemical oxygen demand (COD) removal efficiency of 92.7% ± 2.3% and energy recovery in the form of methane with an organic loading rate of 12.2 ± 6.6 kg-COD·m(-3)·day(-1). The DHS reactor showed a high performance in residual organic matter removal from UASB effluent. In total, the system achieved high-level total COD removal of 98.6% ± 1.2% and total suspended solids removal of 98.0% ± 1.4%. Massive parallel 16S rRNA gene sequencing of the retained sludge in the UASB reactor showed the predominant microbial phyla to be Bacteroidetes, Firmicutes, Proteobacteria, WWE1, and Euryarchaeota. Uncultured bacteria belonging to the phylum Bacteroidetes and Phylum WWE1 were predominant in the UASB reactor. This microbial assemblage utilizes the organic compounds contained in natural rubber processing wastewater. In addition, the methane-producing archaea Methanosaeta sp. and Methanolinea sp. were detected.
The present communication deals with the leaching of gold from the printed circuit boards (PCBs) ... more The present communication deals with the leaching of gold from the printed circuit boards (PCBs) of waste mobile phones using an effective and less hazardous system, i.e., a copper-ammonia-thiosulfate solution, as an alternative to the conventional and toxic cyanide leaching of gold. The influence of thiosulfate, ammonia and copper sulfate concentrations on the leaching of gold from PCBs of waste mobile phones was investigated. Gold extraction was found to be enhanced with solutions containing 15-20. mM cupric, 0.1-0.14. M thiosulfate, and 0.2-0.3. M ammonia. Similar trends were obtained for the leaching of gold from two different types of scraps and PCBs of waste mobile phones. From the scrap samples, 98% of the gold was leached out using a solution containing 20. mM copper, 0.12. M thiosulfate and 0.2. M ammonia. Similarly, the leaching of gold from the PCBs samples was also found to be good, but it was lower than that of scrap samples in similar experimental conditions. In this case, only 90% of the gold was leached, even with a contact time of 10. h. The obtained data will be useful for the development of processes for the recycling of gold from waste mobile phones.
We performed whole-exome sequencing of a family with autosomal dominant Dandy-Walker malformation... more We performed whole-exome sequencing of a family with autosomal dominant Dandy-Walker malformation and occipital cephaloceles and detected a mutation in the extracellular matrix (ECM) protein-encoding gene NID1. In a second family, protein interaction network analysis identified a mutation in LAMC1, which encodes a NID1-binding partner. Structural modeling of the NID1-LAMC1 complex demonstrated that each mutation disrupts the interaction. These findings implicate the ECM in the pathogenesis of Dandy-Walker spectrum disorders.
To identify causes of nonsyndromic cleft lip and palate in a Vietnamese population. In this study... more To identify causes of nonsyndromic cleft lip and palate in a Vietnamese population. In this study, 175 families with at least one case of cleft lip and/or palate were studied using the candidate genes TGFA, MSX1, and TGFB3. Transmission distortion for alleles of MSX1 were demonstrated for the whole population and two missense mutations were identified, including one (P147Q) that is found in approximately 2% of the population. The P147Q appears to arise from a founder individual based on shared haplotypes in unrelated families. MSX1 contributes to nonsyndromic clefting in a Vietnamese population, and consistent with other studies, identifiable mutations in this gene cause about 2% of cases of nonsyndromic clefting.
The incidence of induced abortion (IA) is high in Vietnam. The purpose of this study is to find o... more The incidence of induced abortion (IA) is high in Vietnam. The purpose of this study is to find out whether IA increases the risk of secondary tubal infertility. A case-control study was conducted at Tu Du Hospital in Vietnam between June and September 2001. Interviews were completed with 67 tubal infertility cases matched by age and residence to 67 controls. The median age of subjects was 34 years old. Proportion of subjects with history of IA was 50.8% and 44.8% for cases and controls, respectively. IA did not significantly increase the risk of secondary infertility. Age of first sexual intercourse was under 20 years old for 29.9% of cases and 9.1% of controls, and it significantly increased the risk of secondary infertility [odds ratio (OR)=3.80]. This study was unable to identify IA as a risk factor of secondary tubal infertility. However, the increased OR for age at first sexual intercourse may imply that being sexually active at an earlier age increases the risk of getting both sexually transmitted diseases and unwanted pregnancies and in turn, increasing the risk of infertility. It is recommended to provide young women and men with the information about health risks related to sexual activity.
Ho Tay (West Lake) in Hanoi, Vietnam receives wastewater from the city center and the surrounding... more Ho Tay (West Lake) in Hanoi, Vietnam receives wastewater from the city center and the surrounding residential areas, which can cause both eutrophication and enrichment of toxic heavy metals in the lake ecosystem. The aim of this study is to evaluate the recent trends of metal contamination in this lake from their spatial (horizontal and vertical) distributions in the lake sediments. Sediment cores with up to 70 cm in depth were sampled from four locations in the lake and analyzed for heavy metals (Cd, Cr, Cu, Mn, Ni, Pb and Zn) including a metalloid (As) and total organic carbon (TOC). High concentrations of the metals (except for Mn) and TOC have accumulated in sediment at the site where an inlet of sewage from the city center was located nearby. Increasing trends of the metal contents in the sediment profile toward the surface at the sites distant from the sewage inlets imply that the loads of these metals into this lake have been continuously increasing. In addition, Pb isotopic ratios in sediment profile could be used as an indicator of anthropogenic Pb pollution in the lake.
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