Molecular characterization of serotype A foot-and-mouth disease viruses circulating in Vietnam in 2009

Le, V.P.,Nguyen, T.,Lee, K.N.,Ko, Y.J.,Lee, H.S.,Nguyen, V.C.,Mai, T.D.,Do, T.H.,Kim, S.M.,Cho, I.S.,Park, J.H. Elsevier Scientific Pub. Co 2010 Veterinary microbiology Vol.144 No.1

Foot-and-mouth disease (FMD) is a major cause of endemic outbreaks in Vietnam in recent years. In this work, six serotype A foot-and-mouth disease viruses (FMDV), collected from endemic outbreaks during January and February of 2009 in four different provinces in Vietnam, were genetically characterized for their complete genome sequences. Genetic analysis based on the complete viral genome sequence indicated that they were closely related to each other and shared 99.0-99.8% amino acid (aa) identity. Genetic and deduced aa analysis of the capsid coding gene VP1 showed that the six Vietnamese strains were all classified into the genotype IX from a total of 10 major genotypes worldwide, sharing 98.1-100% aa identity each other. They were most closely related to the type A strains recently isolated in Laos (A/LAO/36/2003, A/LAO/½006, A/LAO/6/2006, A/LAO/7/2006, and A/LAO/8/2006), Thailand (A/TAI/2/1997 and A/TAI/118/1987), and Malaysia (A/MAY/2/2002), sharing 88.3-95.5% nucleotide (nt) identities. In contrast, Vietnamese type A strains showed low nt identities with the two old type A FMDVs, isolated in 1960 in Thailand (a15thailand iso43) and in 1975 in the Philippines (aphilippines iso50), ranging from 77.3 to 80.9% nt identity. A multiple alignment based on the deduced amino acid sequences of the capsid VP1 coding gene of type A FMDV revealed three amino acid substitutions between Vietnamese strains and the strains of other Southeast Asian countries (Laos, Thailand, Malaysia, and the Philippines). Alanine was replaced by valine at residue 24, asparagine by arginine at residue 85, and serine by threonine at residue 196. Furthermore, type A FMDV strains recently isolated in Vietnam, Laos, Thailand, and Malaysia all have one amino acid deletion at residue 140 of the capsid VP1 protein compared with the two old type A FMDV strains from Thailand and the Philippines as well as most other type A representatives worldwide. This article is the first to report on the comprehensive genetic characterization of type A FMDV circulating in Vietnam.

Rapid detection of soils contaminated with heavy metals and oils by laser induced breakdown spectroscopy (LIBS)

Kim, G.,Kwak, J.,Kim, K.R.,Lee, H.,Kim, K.W.,Yang, H.,Park, K. Elsevier Scientific Pub. Co 2013 Journal of hazardous materials Vol.263 No.2

A laser induced breakdown spectroscopy (LIBS) coupled with the chemometric method was applied to rapidly discriminate between soils contaminated with heavy metals or oils and clean soils. The effects of the water contents and grain sizes of soil samples on LIBS emissions were also investigated. The LIBS emission lines decreased by 59-75% when the water content increased from 1.2% to 7.8%, and soil samples with a grain size of 75μm displayed higher LIBS emission lines with lower relative standard deviations than those with a 2mm grain size. The water content was found to have a more pronounced effect on the LIBS emission lines than the grain size. Pelletizing and sieving were conducted for all samples collected from abandoned mining areas and military camp to have similar water contents and grain sizes before being analyzed by the LIBS with the chemometric analysis. The data show that three types of soil samples were clearly discerned by using the first three principal components from the spectral data of soil samples. A blind test was conducted with a 100% correction rate for soil samples contaminated with heavy metals and oil residues.

Enhancement of heavy metal phytoremediation by Alnus firma with endophytic Bacillus thuringiensis GDB-1

Babu, A.G.,Kim, J.D.,Oh, B.T. Elsevier Scientific Pub. Co 2013 Journal of hazardous materials Vol.250 No.-

Phytoremediation shows potential for remediating mine tailing sites contaminated with heavy metals. Our aim was to isolate, characterize, and assess the potential of endophytic bacteria to enhance growth and metal accumulation by the hyperaccumulator Alnus firma. A bacterial strain isolated from roots of Pinus sylvestris had the capacity to remove heavy metals from mine tailing and was identified as Bacillus thuringiensis GDB-1 based on 16S ribosomal DNA sequencing. GDB-1 exhibited plant growth-promoting traits, including 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, indole acetic acid (IAA) and siderophore production, and P solubilization. The efficiency of GDB-1 to remove heavy metals was influenced by pH and initial metal concentration. Removal capacity (mg/l) was 77% for Pb (100), 64% for Zn (50), 34% for As (50), 9% for Cd (10), 8% for Cu (10), and 8% for Ni (10) during the active growth cycle in heavy metal-amended, mine tailing extract medium. Inoculating soil with GDB-1 significantly increased biomass, chlorophyll content, nodule number, and heavy metal (As, Cu, Pb, Ni, and Zn) accumulation in A. firma seedlings. Results indicate that inoculating the native plant A. firma with B. thuringiensis GDB-1 improves its efficiency for phytoremediation of soil containing mine tailings contaminated with heavy metals.

Recycled water sources influence the bioavailability of copper to earthworms

Kunhikrishnan, A.,Bolan, N.S.,Naidu, R.,Kim, W.I. Elsevier Scientific Pub. Co 2013 Journal of hazardous materials Vol.261 No.-

Re-use of wastewaters can overcome shortfalls in irrigation demand and mitigate environmental pollution. However, in an untreated or partially treated state, these water sources can introduce inorganic contaminants, including heavy metals, to soils that are irrigated. In this study, earthworms (Eisenia fetida) have been used to determine copper (Cu) bioavailability in two contrasting soils irrigated with farm dairy, piggery and winery effluents. Soils spiked with varying levels of Cu (0-1000mg/kg) were subsequently irrigated with recycled waters and Milli-Q (MQ) water and Cu bioavailability to earthworms determined by mortality and avoidance tests. Earthworms clearly avoided high Cu soils and the effect was more pronounced in the absence than presence of recycled water irrigation. At the highest Cu concentration (1000mg/kg), worm mortality was 100% when irrigated with MQ-water; however, when irrigated with recycled waters, mortality decreased by 30%. Accumulation of Cu in earthworms was significantly less in the presence of recycled water and was dependent on CaCl<SUB>2</SUB>-extractable free Cu<SUP>2+</SUP> concentration in the soil. Here, it is evident that organic carbon in recycled waters was effective in decreasing the toxic effects of Cu on earthworms, indicating that the metal-organic complexes decreased Cu bioavailability to earthworms.

Influence of visible-light irradiation on physicochemical and photocatalytic properties of nitrogen-doped three-dimensional (3D) titanium dioxide

Lee, H.U.,Lee, S.C.,Choi, S.,Son, B.,Kim, H.,Lee, S.M.,Kim, H.J.,Lee, J. Elsevier Scientific Pub. Co 2013 Journal of hazardous materials Vol.258 No.-

We report highly active visible-light driven nitrogen-doped three-dimensional polycrystalline anatase TiO<SUB>2</SUB> photocatalysts (N-3D TiO<SUB>2</SUB>) for environmental and biomedical applications. N-3D TiO<SUB>2</SUB> is synthesized at a low temperature (<90<SUP>o</SUP>C) without thermal treatment via a modified hydrothermal process (HP) and ultrasound irradiation (UI). The N-3D TiO<SUB>2</SUB> is additionally irradiated with visible-light to improve the hydroxylation of its surface. Under visible-light irradiation, the photocatalytic activity of visible-light irradiated N-3D TiO<SUB>2</SUB> (*N-3D TiO<SUB>2</SUB>; [k]=1.435h<SUP>-1</SUP>) is 26.1 times higher than that of 3D TiO<SUB>2</SUB> ([k]=0.055h<SUP>-1</SUP>). The *N-3D TiO<SUB>2</SUB> is highly recyclable and retained 91.8% of the initial decolorization rate after fifteen cycles. Interestingly, the *N-3D TiO<SUB>2</SUB> shows very strong antibacterial properties against both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) after exposure to visible-light for 3h. The antibacterial properties of *N-3D TiO<SUB>2</SUB> are more effective than those of TiO<SUB>2</SUB>, 3D TiO<SUB>2</SUB>, and N-3D TiO<SUB>2</SUB>. More than 91.3% of the E. coli is sterilized after ten cycles. There are a large increase in the photocatalytic and antibacterial activity of *N-3D TiO<SUB>2</SUB> relative to that of N-3D TiO<SUB>2</SUB> owing to the hydroxylation of the N-3D TiO<SUB>2</SUB> surface as a result of the visible-light irradiation. These results indicate that *N-3D TiO<SUB>2</SUB> might have utility in several promising applications such as highly efficient water/air treatment, inactivation of pathogenic microorganisms, and solar-energy conversion.

Facilitated strontium transport by remobilization of strontium-containing secondary precipitates in Hanfod Site subsurface

Wang, G.,Um, W. Elsevier Scientific Pub. Co 2013 Journal of hazardous materials Vol.248 No.-

Significantly enhanced immobilization of radionuclides (such as <SUP>90</SUP>Sr and <SUP>137</SUP>Cs) due to adsorption and coprecipitation with neo-formed colloid-sized secondary precipitates has been reported at the U.S. Department of Energy's Hanford Site. However, the stability of these secondary precipitates containing radionuclides in the subsurface under changeable field conditions is not clear. Here, the authors tested the remobilization possibility of Sr-containing secondary precipitates (nitrate-cancrinite) in the subsurface using saturated column experiments under different geochemical and flow conditions. The columns were packed with quartz sand that contained secondary precipitates (nitrate-cancrinite containing Sr), and leached using colloid-free solutions under different flow rates, varying pH, and ionic strength conditions. The results indicate remobilization of the neo-formed secondary precipitates could be possible given a change of pH of ionic strength and flow rate conditions. The remobility of the neo-formed precipitates increased with the rise in the leaching solution flow rate and pH (in a range of pH 4-11), as well as with decreasing solution ionic strength. The increased mobility of Sr-containing secondary precipitates with changing background conditions can be a potential source for additional radionuclide transport in Hanford Site subsurface environments.

Glutaraldehyde-crosslinked chitosan beads for sorptive separation of Au(III) and Pd(II): Opening a way to design reduction-coupled selectivity-tunable sorbents for separation of precious metals

Park, S.I.,Kwak, I.S.,Won, S.W.,Yun, Y.S. Elsevier Scientific Pub. Co 2013 Journal of hazardous materials Vol.248 No.-

Glutaraldehyde (GA)-crosslinked chitosan beads (GA-CS) are prepared with coagulating solution containing sodium tripolyphosphate and GA, and used for the adsorption of metals from binary-metal solution Au(III) and Pd(II). GA-CS exhibited selective sorption of Au(III) in the Au(III)-Pd(II) mixture. X-ray diffraction analyses showed that Au(III) was reduced to Au(0) following sorption, while Pd(II) was present as unreduced divalent form. Increased GA led to more selectivity toward Au(III), indicating that Au(III) selectivity is attributed to reduction-couple sorption of Au(III) with a reducing agent GA. Furthermore, a 2-step desorption process enabled selective recovery of Pd and Au using 5M HCl and 0.5M thiourea-1M HCl, respectively, leading to pure Pd(II) and Au(III)-enriched solutions. This finding may open a new way to design reduction-coupled selectivity-tunable metal sorbents by combination of redox potentials of metal ions and reducing agents.

Amines immobilized double-walled silica nanotubes for CO₂ capture

Ko, Y.G.,Lee, H.J.,Oh, H.C.,Choi, U.S. Elsevier Scientific Pub. Co 2013 Journal of hazardous materials Vol.250 No.-

Novel silica support has been required for high amine loading and good CO<SUB>2</SUB> molecule diffusion into its pores to increase the performance of CO<SUB>2</SUB> adsorbents. Herein, amine groups supported on double-walled silica nanotubes (DWSNTs) have been prepared via the immobilization of various aminosilanes (primary, secondary, tertiary, di-, and tri-aminosilanes) on DWSNT, and found to be a very effective adsorbent for CO<SUB>2</SUB> capture. Amine groups immobilized DWSNTs captured CO<SUB>2</SUB> reversibly in a temperature swing process at various adsorption temperatures (25<SUP>o</SUP>C, 50<SUP>o</SUP>C, 75<SUP>o</SUP>C, and 100<SUP>o</SUP>C). The amines on modified DWSNTs showed high CO<SUB>2</SUB> capture capacity in the order of tri-, di-, primary, secondary, and tertiary amines. The CO<SUB>2</SUB> capture capacity of all aminosilanes immobilized DWSNTs decreased linearly with the increase of the adsorption temperature. We expect that DWSNT would be able to inspire researchers to use it not only as a support for CO<SUB>2</SUB> capture but also as a promising candidate for various applications.

Degradation and toxicity assessment of sulfamethoxazole and chlortetracycline using electron beam, ozone and UV

Kim, T.H.,Kim, S.D.,Kim, H.Y.,Lim, S.J.,Lee, M.,Yu, S. Elsevier Scientific Pub. Co 2012 Journal of hazardous materials Vol.227 No.-

Recently, the occurrence of antibiotics in sewage treatment plant effluent, as well as drinking water, has raised concern about their potential impacts on the environment and public health. Antibiotics are found in surface and ground waters, which indicate their ineffective removal by conventional wastewater treatment processes. Therefore, advanced oxidation processes (AOPs) have received considerable attention for the removal of antibiotics. This study was conducted to evaluate the degradation and mineralization of antibiotics (sulfamethoxazole and chlortetracycline) using an electron beam, ozone and UV, and the change of toxicity. Also, the electrical energy consumption based on the EE/O parameter (the electrical energy required per order of pollutants removal in 1m<SUP>3</SUP> wastewater) was used to quantify the energy cost associated with the different AOPs (electron beam, ozone and UV) for the degradation of antibiotics. The results showed that an electron beam effective for the removals of both sulfamethoxazole and chlortetracycline in aqueous solutions. However, degradation of the target compounds by ozone and UV showed different trends. The oxidation efficiency of each organic compound was very dependent upon the AOP used. Algal toxicity was significantly reduced after each treatment. However, based on the electrical energy, the electron beam was more efficient than ozone and UV. Electron beam treatment could be an effective and safe method for the removal of antibiotic compounds.

Synthesis of mesoporous MgO catalyst templated by a PDMS-PEO comb-like copolymer for biodiesel production

Jeon, H.,Kim, D.J.,Kim, S.J.,Kim, J.H. Elsevier Scientific Pub. Co 2013 Fuel processing technology Vol.116 No.-

Mesoporous MgO catalyst was synthesized from Mg(NO<SUB>3</SUB>)<SUB>2</SUB> via a sol-gel process by templating an amphiphilic comb-like copolymer, poly(dimethylsiloxane-ethylene oxide) (PDMS-PEO). The copolymer morphology was worm-like and microphase-separated in a good solvent but micellar in a selective solvent, such as toluene and water. By templating micelles of PDMS-PEO copolymer, mesoporous MgO with a high surface area was generated after calcination at 500<SUP>o</SUP>C, as confirmed by thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption/desorption measurements. Mesoporous MgO was used as a heterogeneous solid catalyst to produce biodiesel from canola oil. PDMS-PEO templated MgO (t-MgO) converted biodiesel more efficiently (~98.2% methyl ester content) than non-templated MgO (nt-MgO, 82.8%). The number and strength of basic sites of MgO catalyst were also investigated using CO<SUB>2</SUB>-temperature-programmed desorption (CO<SUB>2</SUB>-TPD) analysis.