The effect of titanium dioxide exposure on the thermal properties of Zebrafish (<Emphasis Type="Italic">Danio rerio</Emphasis>) bones

This article presents the changes in the thermal properties of the control and titanium dioxide (TiO₂), both nano and bulk exposed Zebrafish bones by using thermo analytical techniques. The result shows that the mass loss due to the thermal decomposition occurs in three distinct steps due to loss of water, organic and inorganic materials. The titanium dioxide exposed bones present a different thermal behaviour compared to the control bones. The residue masses are found to be increased due to titanium dioxide exposure. In particular, nano titanium dioxide exposure increases the residue mass level significantly (three fold) when compared to titanium dioxide bulk exposure. These thermal characteristics can be used as a qualitative method to check the metal oxide intoxication in biological samples.     

DNA vaccine containing the mycobacterial hsp65 gene prevented insulitis in MLD-STZ diabetes

Background  

Our group previously demonstrated that a DNA plasmid encoding the mycobacterial 65-kDa heat shock protein (DNA-HSP65) displayed prophylactic and therapeutic effect in a mice model for tuberculosis. This protection was attributed to induction of a strong cellular immunity against HSP65. As specific immunity to HSP60 family has been detected in arthritis, multiple sclerosis and diabetes, the vaccination procedure with DNA-HSP65 could induce a cross-reactive immune response that could trigger or worsen these autoimmune diseases.     

Experimental calibration and field investigation of the oxygen isotopic fractionation between biogenic aragonite and water

Marine molluscs have long been recognised as potential records of palaeoclimate change using the patterns and differences in the stable isotopic composition of the carbonate shells. The aim of this study is to improve the robustness of this approach for aragonitic molluscs by completing the first experimental calibration of the fractionation between water and biogenic aragonite. Fractionation factors were calibrated by growing specimens of the freshwater mollusc Lymnaea peregra under controlled conditions of water temperature and isotopic composition. Fifteen populations of L. peregra were maintained at constant temperature and isotopic conditions for five months (at five different temperatures and using three different water compositions). Water samples and temperature measurements were taken regularly throughout the experiment. The temperature dependence of the fractionation factor, between 8 and 24 degrees C, is given by: 1000 ln alpha=16.74x(1000T(-1))-26.39 (T in Kelvin) and the relationship between temperature (T), delta(18)O(carb) and delta(18)O(wat) is given by: T=21.36-4.83xdelta(+ degrees )O(carb)-delta(+ degrees )O(wat) (T is in degrees C, delta(18)O(carb) is with respect to Vienna Pee Dee Belemnite (PDB), the International Atomic Energy Agency (IAEA) replacement standard for PDB, and delta(18)O(wat) is with respect to Vienna standard mean ocean water (VSMOW)) The outcome of the controlled experiment is compared with previous studies on synthetic, and biogenic, calcite and aragonite from field and laboratory investigations. These comparisons suggest that although a vital offset exists between the fractionation of isotopes in synthetic and biogenic aragonite for molluscs in general, there is no vital effect that is specific either to freshwater, or to individual, genera. Therefore, the calibrated relationship may be used for any freshwater or marine mollusc to derive palaeotemperatures providing the isotopic composition of the environmental water can be reliably constrained. Copyright 1999 John Wiley & Sons, Ltd.     

Adsorption of polyacrylic acid and its copolymers with acrylonitrile on zinc oxide particles

Adsorption of polyacrylic acid and its copolymers with acrylonitrile, containing different quantities of carboxyl groups, on the dispersion of zinc oxide was investigated. The kinetics of polymer desorption was investigated based on data concerning the change in concentration of free carboxylic groups of polymer and zinc ions in solution. The concentration of free carboxyl groups decreases and the concentration of zinc ions in the liquid phase above the residue after separation of zinc oxide particles increases with time, reaching a constant value. The dependence of the concentration of free carboxyl groups and zinc ions in the liquid phase on the initial concentration of polymer in the plateau section of the kinetic curve was investigated. Adsorption isotherms of copolymers depend on their solubility in water and can be described by different mathematical models.     

Kinetics of copper dissolving in the water solution of polyacrylic acid or its copolymers with acrylonitrile and hydrogen peroxide

During the coating of metal plates by carboxyl-containing polymers from their solutions or dispersions, adsorption of the polymer onto the surface and oxidation of the metal by oxygen take place. Adsorption of polyacrylic acid and its copolymers with acrylonitrile at the copper surface and kinetics of copper dissolving in the presence of carboxyl-containing polymers and hydrogen peroxide have been investigated. The adsorption of polymers at the surface of the copper powder passes through a maximum when the content of acrylonitrile in copolymers rises. The rate at which copper dissolves increases with increased polymer concentration in solution, reaching a constant value, and does not depend on the hydrogen peroxide concentration. The rate at which copper dissolves depends on the rate of copper oxidation by hydrogen peroxide in the adsorption layer and the rate of polymer desorption. The increase of the solution pH leads to a decrease in the adsorption of polyacrylic acid at the copper surface and the rate at which copper dissolves in the presence of hydrogen peroxide.     

Bioconcentration of zinc and its effect on the biochemical constituents of the gill tissues of Labeo rohita: An FT-IR study

In the present work, an attempt has been made to assess the bioconcentration and distribution of zinc on the selected organs of Labeo rohita and to study the effect of zinc exposure on the biochemical constitutions of gill tissues of L. rohita by using FT-IR Spectroscopy. The concentration pattern in the organs reveals that the liver is the prime site of metal binding and muscle accumulates least metal concentration. The accumulation profile is in the order: liver > gill > kidney > brain > bone > muscle. It has also been observed that the administration of chelating agent d-Penicillamine (DPA) reduces the zinc concentration in all tissues more effectively than the administration of the chelating agent Ethylene Diamine Tetra Acetic acid. The FT-IR spectra reveal that zinc exposure causes significant changes in the biochemical constitutions of the gill tissues. It causes an alteration in the protein secondary structures by decreasing the α-helix and increasing the β-sheet contents. Further, it has been observed that the administration of chelating agent DPA improves the protein and lipid contents in the gill tissues compared to zinc exposed tissues. This result shows that DPA is the effective chelator of zinc in reducing the body burden of L. rohita fingerlings. In conclusion, the findings of the current study suggest that zinc exposure causes significant changes in both lipids and proteins of the gill tissues, and changes the protein profile in favour of β-sheet structure.     

Arsenic-Induced Biochemical Changes in Labeo rohita Kidney: An FTIR Study

ABSTRACT

Arsenic is a toxic heavy metal that occurs naturally in water, soil, and air. It is widespread in the environment as a consequence of both anthropogenic and natural processes. In the current study, an attempt has been made to analyze the arsenic-induced molecular changes in macromolecular components like proteins and lipids in the kidney tissues of edible fish Labeo rohita using Fourier transform infrared (FTIR) spectroscopy. The FTIR spectrum of kidney tissue is quite complex and contains several bands arising from the contribution of different functional groups. The detailed spectral analyses were performed in three distinct wave number regions, namely 3600–3050 cm^?1, 3050–2800 cm^?1, and 1800–800 cm^?1. The current study shows that the kidney tissues are more vulnerable to arsenic intoxication. FTIR spectra reveal significant differences in both absorbance intensities and areas between control and arsenic-intoxicated kidney tissues; this result indicates that arsenic intoxication induces significant alteration on the major biochemical constituents such as lipids and proteins and leads to compositional and structural changes in kidney tissues at the molecular level. The current study confirms that FTIR spectroscopy can be successfully applied to toxicologic and biological studies.     

Vibrational spectroscopy of structural defects in oligothiophenes

Vibrational spectra of oligothiophenes with structural defects are calculated within the density-functional-theory methodology. The effects of the defective αβ linkages on the infrared (IR) and Raman spectra are characterized from calculations of all isomers up to the hexamer. The signatures of αβ linked monomers can be found in IR spectra from broken symmetry arguments which result in absorptions localized in the defective region. The positions of the absorption peaks in the Raman spectra seem to be unaffected by the presence of such defects; however, strong reductions in the intensities are observed because of the shortening of the conjugation length.     

Peculiarities of Polyacrylic Acid Adsorption on Copper Oxide Powder

The adsorption of polyacrylic acid on copper(II) oxide powder from aqueous solutions was studied. The amount of the adsorbed polymer was shown to increase with time reaching its maximum over 6–7 min. The desorption kinetics of copper polyacrylates was studied by measuring variations in copper ion concentration in the solution. The rate of desorption was found to be independent of the initial concentration of polyacrylic acid. A decrease in the dispersed phase concentration did not actually affect the initial rate of the polymer desorption. However, it caused a drastic fall in the rate of desorption after 1–1.5 min. A mathematical model was proposed for describing the experimental data.     

Kinetics of Adsorption and Desorption of Poly(ethylenimine) and Its Complex with Copper(II) on Copper(II) Oxide Powder

Adsorption of poly(ethylenimine) and complexes of poly(ethylenimine) with copper(II) ions on copper(II) oxide powder has been investigated. The rate of adsorption and reaction between poly(ethylenimine) and CuO is very fast. The desorption rate of the complex of poly(ethylenimine) with copper(II) ions is slower and decreases when the initial polymer concentration is decreased. The desorption rate passes through a minimum when the initial concentration of CuO powder in the mixture increases. A mathematical model of polymer adsorption and desorption is proposed. Copyright 2000 Academic Press.