Measurements of radon concentration in drinking water samples from Kastamonu (Turkey)

Concentration of (222)Rn was determined in selected natural spring and tap water samples collected during spring and summer seasons from Kastamonu, Turkey. The aim of this work was to produce a map of the radon concentrations in water sources of the province and to determine any potential radiological risk for the local population. Radon measurements were performed by an AlphaGUARD radon gas analyser. The average radon concentrations were found to vary from 0.39±0.02 to 12.73±0.39?Bq?l(-1) for natural springs and from 0.36±0.04 to 9.29±0.45?Bq?l(-1) for tap water in spring, from 0.50±0.09 to 19.21±1.00?Bq?l(-1) for natural springs and from 0.31±0.03 to 13.14±0.38?Bq?l(-1) for tap water in summer. Furthermore, the results are compared with international recommendations and concentrations reported for other countries. Doses resulting from the consumption of these waters were calculated. The effective dose equivalents due to the intake of the (222)Rn present in these waters are expected to range from 0.93 to 32.54?μSv?y(-1) in summer and from 0.80 to 49.09?μSv?y(-1) in spring.     

Purification of transferrin by magnetic immunoaffinity beads

Immunoaffinity adsorbent for transferrin (Tf) purification was prepared by immobilizing anti‐transferrin (Anti‐Tf) antibody on magnetic monosizepoly(glycidyl methacrylate) beads, which were synthesized by dispersion polymerization technique in the presence of Fe₃O₄nanopowder and obtained with an average size of 2.0 μm. The magnetic poly(glycidyl methacrylate) (mPGMA) beads were characterized by Fourier transform infrared spectroscopy, swelling tests, scanning electron microscopy, electron spin resonance spectroscopy, thermogravimetric analysis and zeta sizing analysis. The density and swelling ratio of the beads were 1.08 g/cm³ and 52%, respectively. Anti‐Tf molecules were covalently coupled through epoxy groups of mPGMA. Optimum binding of anti‐Tf was 2.0 mg/g. Optimum Tf binding from aqueous Tf solutions was determined as 1.65 mg/g at pH 6.0 and initial Tf concentration of 1.0 mg/mL. There was no remarkable loss in the Tf adsorption capacity of immunoaffinity beads after five adsorption–desorption cycles. Tf adsorption from artificial plasma was also investigated and the purity of the Tf molecules was shown with gel electrophoresis studies.     

Measurements of radon concentration in drinking water samples from Kastamonu (Turkey)

Concentration of ²²²Rn was determined in selected natural spring and tap water samples collected during spring and summer seasons from Kastamonu, Turkey. The aim of this work was to produce a map of the radon concentrations in water sources of the province and to determine any potential radiological risk for the local population. Radon measurements were performed by an AlphaGUARD radon gas analyser. The average radon concentrations were found to vary from 0.39±0.02 to 12.73±0.39 Bq l^?1 for natural springs and from 0.36±0.04 to 9.29±0.45 Bq l^?1 for tap water in spring, from 0.50±0.09 to 19.21±1.00 Bq l^?1 for natural springs and from 0.31±0.03 to 13.14±0.38 Bq l^?1 for tap water in summer. Furthermore, the results are compared with international recommendations and concentrations reported for other countries. Doses resulting from the consumption of these waters were calculated. The effective dose equivalents due to the intake of the ²²²Rn present in these waters are expected to range from 0.93 to 32.54 μSv y^?1 in summer and from 0.80 to 49.09 μSv y^?1 in spring.     

Analytical formulas for calculating photoelectric attenuation coefficients

Photoelectric absorption is an interaction in which an incoming gamma ray virtually transfers all of its energy to an atomic electron, usually the most tightly bound K-shell electron of an atom. This paper uses the Win XCOM computer code as a reference base. We found analytical photoelectric attenuation coefficients for researchers using the Monte Carlo simulation program for Z∈ [1; 100] and E∈[10 keV; 3 MeV]. We define a photoelectric effect operator and coefficient operators and a series for photoelectric absorption. We have calculated two polynomial coefficient operators for use with XCOM for photoelectric absorption. We determined 14 energies and atomic number limits for elements, and we find that they are accurate limits of photoelectric absorption for fitting with XCOM.     

Quartz crystal microbalance immunosensor for the detection of antibodies to double-stranded DNA

We report the development of a novel quartz crystal microbalance immunosensor with the simultaneous measurement of resonance frequency and motional resistance for the detection of antibodies to double-stranded DNA (dsDNA). The immobilization of poly(l-lysine) and subsequent complexation with DNA resulted in formation of a sensitive dsDNA-containing nanofilm on the surface of a gold electrode. Atomic force microscopy has been applied for the characterization of a poly(l-lysine)–DNA film. After the blocking with bovine serum albumin, the immunosensor in flow-injection mode was used to detect the antibodies to dsDNA in purified protein solutions of antibodies to dsDNA and to single-stranded DNA, monoclonal human immunoglobulin G, DNase I and in blood serum of patients with bronchial asthma and systemic lupus erythematosus. Experimental results indicate high sensitivity and selectivity of the immunosensor. In memoriam Prof. Victor G. Vinter     

Synthesis and properties of new fullerene C60 derivatives,containing acetonide and polyol fragments

New mono- and hexa-methanofullerenes containing different number of acetonide groups are synthesized and characterized. Removing the acetonide protection leads to new chromatographically pure water-soluble polyol methanofullerenes with essentially quantitative yields.     

A Robust,Precious‐Metal‐Free Dye‐Sensitized Photoanode for Water Oxidation: A Nanosecond‐Long Excited‐State Lifetime through a Prussian Blue Analogue

Herein, we establish a simple synthetic strategy affording a heterogeneous, precious metal‐free, dye‐sensitized photoelectrode for water oxidation, which incorporates a Prussian blue (PB) structure for the sensitization of TiO₂ and water oxidation catalysis. Our approach involves the use of a Fe(CN)₅ bridging group not only as a cyanide precursor for the formation of a PB‐type structure but also as an electron shuttle between an organic chromophore and the catalytic center. The resulting hetero‐functional PB‐modified TiO₂ electrode demonstrates a low‐cost and easy‐to‐construct photoanode, which exhibits favorable electron transfers with a remarkable excited state lifetime on the order of nanoseconds and an extended light absorption capacity of up to 500 nm. Our approach paves the way for a new family of precious metal‐free robust dye‐sensitized photoelectrodes for water oxidation, in which a variety of common organic chromophores can be employed in conjunction with CoFe PB structures.     

Forensic Identification of Dyes in Ballpoint Pen Inks Using LC–ESI–MS

The aim of this work was to develop a new technique using flow injection analysis combined with LC–ESI–MS which allows identification of dyes in ballpoint pen inks. A sample preparation procedure for the extraction of dyes from ballpoint pen strokes has been developed. The characteristic group of ions for each sample of 21 studied ballpoint pen inks corresponding to the present dyes has been determined using flow injection method. LC separation conditions for identified dyes have been optimized on reversed-phase sorbent based on silica gel. The best composition of the mobile phase for the dyes mixture LC separation was 0.1% aqueous formic acid and acetonitrile. Detection of dyes was carried out using mass spectrometry with electrospray ionization in positive and negative modes after reversed-phase liquid chromatography separation. Dye composition of ink was additionally confirmed comparing the data obtained from the literature. Flow injection analysis allows obtaining intensive ions of unknown strokes. It is difficult to get this information using only chromatographic methods, because dyes peak intensity can be low and noise of basic line high. Flow injection method allows distinguishing the analyzed 21 ballpoint pens by determining a characteristic set of dyes. The developed flow injection technique is very simple and quick. As a result, a novel approach for the identification of dyes in the ballpoint pen inks by flow injection analysis with LC–ESI–MS and UV detection without using standard dye samples has been established. It can be an effective alternative to the existing LC–DAD–MS and IR spectroscopy methods.     

Interfacing multicellular organisms with polyelectrolyte shells and nanoparticles: a Caenorhabtidis elegans study

We report the surface modification of microscopic live multicellular nematodes Caenorhabtidis elegans with polyelectrolyte multilayers (pure and doped with 20 nm gold nanoparticles) and the direct magnetic functionalization of nematodes with biocompatible magnetic nanoparticles. Magnetically functionalized "ironoxideclad" nematodes can be effectively separated and moved using an external magnetic field. The surface-functionalized nematodes preserve their viability and reproduction.     

Theoretical study on the investigation of antioxidant properties of some hydroxyanthraquinones

Anthraquinones are located in an important class of natural compounds having antioxidant properties. Quantum chemical calculations based on the density functional theory were employed to study the relationship between the structure and the antioxidant activity of four hydroxyanthraquinones. The solvation effects on the antioxidant activity were taken into account by using the conductor-like polarisable continuum model with different dielectric constants (ε = 2.25, C₆H₆; ε = 78.39, H₂O). The three antioxidant action mechanisms, hydrogen atom transfer (HAT), single electron transfer-proton transfer and sequential proton loss electron transfer (SPLET) were elucidated. The reaction enthalpies related to the steps in these mechanisms were computed in gas phase and solvents. The calculated results are in line with experimental values. The results showed that HAT was the most favourable mechanism for describing the antioxidant activity of hydroxyanthraquinones in the gas phase and in benzene, whereas in aqueous solution, SPLET represented the most thermodynamically plausible reaction pathway.