Three antimicrobial nanoparticle types (AMNP0, AMNP1, and AMNP2) produced using the TesimaTM thermal plasma technology were investigated and their compositions were determined using a combination of analytical methods. Scanning electron micrographs provided the morphology of these particles with observed sizes ranging from 10 to 50 nm, whilst FTIR spectra confirmed the absence of polar bonds and organic impurities, and strong Raman active vibrational bands at ca. 1604 and 1311 cm−1 ascribed to C–C vibrational motions were observed. Carbon signals that resonated at δC 126 ppm in the solid state NMR spectra confirmed that sp2 hybridised carbons were present in high concentration in two of the nanoparticle types (AMNP1 and AMNP2). X-ray powder diffraction suggested that AMNP0 contains single phase Tungsten carbide (WC) in a high state of purity and multiple phases of WC/WC1-x were identified in both AMNP1 and AMNP2. Finally, X-ray photoelectron spectral (XPS) analyses revealed and quantified the elemental ratios in these composite formulations.
Date of Acceptance: 29/12/2014Antibacterial Cu bearing stainless steels (CuSS) have been developed recently and their performance has attracted significant attention widely in biomedical, healthcare and environmental facilities in cross-disciplines. The antibacterial ability and its efficiency of the CuSS are associated to the rate and concentration of Cu2z ions releases from its surface. The surface properties such as corrosion resistance are also influenced by the amount and the rate of Cu ions released. Thus, the aim of this study focused on the determination of trace release amount of Cu2+ ions from a typical copper bearing 304 stainless steel (304CuSS). Meanwhile, the release of other key elements in the material such as Cr, Fe, Ni were also examined, and found these multiple elemental releases produced a highly synergistic effect on killing bacterium. The release rate of the metals from 304CuSS was conducted by an inductively coupled plasma optical emission spectrometry (ICP-OES). In this study, the commercial 304 stainless steel (304SS) was served as a control material, while the ICP results showed that the Cu2z ions released from 304CuSS were maintained a constant level with a release rate as low as 0?8 ppb/day/cm2. This phenomenon could be explained by a coordinating role or synergistic effects of Cu, Fe, Cr, and Ni ions. XPS surface composition analysis showed a releases contribution results in day 1 and day 14 that the reduction trend of Cu quantities in through of the surface depth of 304CuSS is consistent and comprehensible
Measurements are reported of the uptake equilibria and kinetics of seven chlorobenzenes: 1,2–dichlorobenzene, 1,3–di‐chlorobenzene, 1,2,4–trichlorobenzene, 1,2,3,4–tetrachlorobenzene, 1,2,3,5–tetrachlorobenzene, pentachlorobenzene, and hexachloro‐benzene from water into tissues (leaves, petioles, stems, and roots) of 6–8–week‐old soybean plants, Glycine max L. Equilibrium was reached within 1–4 days, with uptake of the more hydrophobic chemicals being slightly slower. Aqueous solubilities of three of these chlorobenzenes are reported. Linear correlations were obtained between the equilibrium tissue‐water partition coefficients, the chemicals' octanol‐water partition coefficients and the measured lipid contents. A correlation approach is proposed that may be useful for assessment of the extent of uptake of persistent hydrophobic chemicals by plants from soil and the atmosphere.
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