Technique for measuring metallic salt effects upon the indigenous heterotrophic microflora of a natural water

The effects of several concentrations of the metallic salts Ag₂SO₄, NaAsO₃, BaCl₂2H₂O, CdCl₂2.5 H₂O, CrCl₂6H₂O, CuCl₂, HgCl₂, NaCl, NiCl₂6H₂O, PbCl₂ and ZnCl₂ upon the indigenous heterotrophic microflora of a natural water were studied. Effects of these salts upon the heterotrophic activity of the microbes were assayed using the heterotrophic technique whereas lethal effects upon the heterotrophic bacteria were determined using nutrient agar plate counts. The heterotrophic activity method is based upon the uptake and mineralization of a radioactively labeled metabolite (in these experiments ¹⁴C-glucose) by the indigenous aquatic microbes and data analysis is by Michaelis—Menten enzyme kinetics equations. Concentrations of metallic salts which resulted in bacterial death also caused erratic uptake and mineralization rates of ¹⁴C-glucose whereas sub-lethal concentrations, as determined by nutrient agar plate counts, caused a non-competitive inhibition of maximum heterotrophic activity and markedly increased the turnover time of the glucose substrate.     

Marine paint fomulations: Conducting polymers as anticorrosive additives

Within coating technology, there is increasing interest in the development of efficient anticorrosive additives able to replace the conventional inorganic anticorrosive pigments usually added to paints, which may have detrimental effects on both environment and health. A number of recent studies have evidenced that the modification of a paint formulation by the addition of a low concentration of conducting polymer (0.2–0.3%, w/w) increases significantly the protective properties of the coating. Here we focus on the principles of anticorrosive additives based on conducting polymers for marine paints. The article reviews the most important findings achieved in recent studies. The relevant factors that are determinant for the anticorrosive protection imparted by conducting polymers, as the doping level, the miscibility with paint, the electrochemical stability, etc., are discussed in detail.     

Developmental variations in plasma leptin,leptin soluble receptor and their molar ratio in healthy infants

Background  

Leptin and its soluble receptor (sOB-R) are important to regulation of body composition but there are no data on the developmental variations in these plasma variables and their relationship with body composition measurements,     

Electrochemical Synthesis of Poly(3,4-ethylenedioxythiophene) on Steel Electrodes: Properties and Characterization

Electrodeposition of poly(3,4-ethylenedioxythiophene) by electrochemical polymerization of 3,4-ethylenedioxythiophene has been performed on steel electrodes rather than on the typically used inert electrodes (Pt, Au, graphite carbon). The polymer was generated by cyclic voltammetry, chronopotentiometry and chronoamperometry from a 10 mM monomer solution in acetonitrile with 0.1 M LiClO₄. Elemental analysis of the generated polymer indicated that the monomeric units support 0.54 positive charges balanced with CIO₄ ¹⁴⁻ counterions. Electrochemical, electrical and structural properties of the prepared material have been characterized. The good adherence of films combined with its excellent properties indicate that poly(3,4-ethylenedioxythiophene) can be a suitable material for anticorrosion applications.     

Quantification of N-(deoxyguanosin-8-yl)-4-aminobiphenyl adducts in human lymphoblastoid TK6 cells dosed with N-hydroxy-4-acetylaminobiphenyl and their relationship to mutation, toxicity, and gene expression profiling

Gene expression profiles that are anchored to phenotypic endpoints may lead to the identification of signatures that predict mutagenicity or carcinogenicity. The study presented here describes the analysis of DNA adducts in the human TK6 lymphoblastoid cell line after exposure to N-hydroxy-4-aminobiphenyl, a mutagenic metabolite of 4-aminobiphenyl. A validated nano-LC microelectrospray mass spectrometry assay is reported for the detection and quantification of N-(deoxyguanosin-8-yl)-4-aminobiphenyl (dG-C8-ABP), the principal DNA adduct of 4-aminobiphenyl. Limits of quantification, based on a signal-to-noise ratio of 10:1, are determined to correspond to approximately 27 fg of dG-C8-ABP injected on-column. The assay has been used to measure the steady-state levels of the adduct in the human TK6 lymphoblastoid cell line as a function of dose (0.5, 1.0, and 10.0 microM) and time (2, 6, and 27 h) after exposure to N-hydroxy-4-aminobiphenyl. The levels of dG-C8-ABP adducts in the cells, ranging from 18 to 500 adducts in 10(9) nucleotides, were then correlated to cell toxicity, induced mutation at the TK (thymidine kinase) and HPRT loci, and gene expression profiling through microarray analysis. Cell cultures were evaluated for toxicity by growth curve extrapolation, mutation assays were performed on the HPRT and TK loci, and gene expression profiles were generated by analyses using microarray technology. In the mutation assay analysis, as the toxicant concentration increased, there was an increase in mutation fraction, indicating a direct correlation to metabolite dosing level and mutations occurring at these two loci. Statistical analysis of the gene expression data determined that a total of 2250 genes exhibited statistically significant changes in expression after treatment with N-OH-AABP (P < 0.05). Among the genes identified, 2245 were up-regulated, whereas 5 genes that had functions in cell survival and cell growth and, hence, could be indicators of toxicity, were down-regulated relative to controls. The results demonstrate the value of anchoring gene expression patterns to phenotypic markers, such as DNA adduct levels, toxicity, and mutagenicity.     

Direct characterization of commercial lecithins by easy ambient sonic-spray ionization mass spectrometry

Commercial lecithins are composed mainly of phospholipids and triacylglycerols. The analysis of the commercial lecithins, including their fraction of phospholipids, normally involves laborious and expensive protocols. Easy ambient sonic-spray ionization mass spectrometry (EASI-MS) is shown to be an efficient technique for the analysis of lipids. Samples of commercial lecithins including standards, refined, deoiled and modified soy lecithin were tested. Characteristic profiles of phosphatidylcholines and triacylglycerols are detected by EASI(+)-MS, whereas EASI(-)-MS provided phosphatidylethanolamines, glycophospholipids and free fatty acids profiles. Acetylated lecithins also displayed characteristic acetylated derivatives. EASI-MS data was also compared to MALDI-MS, and found to display richer compositional information. The industrial process applied to lecithin fabrication was also characterised via typical EASI-MS profiles. EASI-MS both in its positive and negative ion modes offers a direct, fast and efficient technique able to characterise commercial lecithin.     

Polyaniline, polypyrrole and poly(3,4-ethylenedioxythiophene) as additives of organic coatings to prevent corrosion

The aim of this work is to compare the protection against corrosion imparted by different conducting polymers when these materials are used as anticorrosive additives in the formulation of conventional epoxy paints. Specifically, the polymers employed as anticorrosive additives are polyaniline emeraldine salt, polyaniline emeraldine base, polyaniline emeraldine salt composite with carbon black, polypyrrole composite with carbon black and poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulphonate). Initially, the structural, thermal and mechanical properties of the unmodified epoxy paint as well as the modified coatings, obtained by the addition of 0.3 wt.% of conducting polymers, have been characterized. After this, controlled accelerated corrosion assays in an aggressive solution medium were developed using coated steel panels. Results indicate that the protection against corrosion imparted by the formulations modified by the addition of poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulphonate), polyaniline emeraldine salt and, especially, polyaniline emeraldine base is significantly higher than that of the unmodified paint. In contrast, the use of conducting polymer composite with carbon black reduces the efficacy of the coating. Results indicate that some conducting polymer compositions should be considered as a suitable alternative to replace inorganic anticorrosive pigments currently used in paint formulations.     

Examining spatial patterns in affordable housing: the case of California density bonus implementation

California State Density Bonus Law §65915–18 financially incentivizes housing developers to produce affordable housing by granting density bonuses to those who designate a percentage of the total units for residence by low or moderate income households. By incorporating affordable housing units alongside market-rate units, state density bonus law fosters opportunities to enhance neighborhood level socio-economic diversity. This paper investigates the effectiveness of density bonus policy at promoting socio-economic diversity within the City of San Diego by examining locational patterns of density bonus implementation and neighborhood demographic characteristics. This study utilizes spatial and non-spatial statistical analyses to identify trends and correlations in density bonus usage, housing stock, and racial and economic characteristics. The results indicate that density bonus usage in San Diego has not fostered socio-economic integration; rather its usage is clustered in neighborhoods characterized by high concentrations of Hispanics, Blacks, and multi-family housing units. The findings underscore the need to refine supply-side affordable housing tools so that they are effective in a range of land markets, and not only in the traditionally lower value land markets where minority households tend to reside.