(137)Cs and (40)K activity concentration measurements and elemental analysis in lichen samples collected from the Giresun province of northeastern Turkey

About 21 years after the Chernobyl accident, (137)Cs and (40)K activity concentration measurements using gamma-ray spectroscopy and elemental analysis using energy dispersive X-ray spectroscopy were performed in five different lichen species collected from the Giresun province of northeastern Turkey. Being a symbiosis of algae and fungi, lichens are mostly used for environmental measurements since the fungal partner is responsible for the uptake of necessary nutrients or harmful substances, such as heavy metals of radionuclides. The gamma activity results showed that (137)Cs, an artificial radionuclide released from the Chernobyl power plant accident, is still eminent in the environment of the province. The mean activity concentrations of (137)Cs and (40)K ranged from 24 to 254 with the mean value of 102 Bq kg(-1) and from 345 to 2103 with the mean value of 1143 Bq kg(-1) in dry weight. The results of the elemental analyses showed potassium, calcium, titanium, iron, tin, and barium in different concentrations.     

Mercaptokomplexe von Indium(III)

The complexes of In(III) with thioglycolate (HO? CH₂? CH₂? S^?) have been investigated by pH-metric methods. Only the mononuclear species In(SR)_n(3-n)+ (n = 1, 2, 3, 4) are formed (Fig. 1): It was difficult to obtain an accurate value for the first stability constant K₁ because of the high stability of the 1:1-complex and therefore mixtures of KCl-KNO₃ were used to keep up the ionic strength of μ = 0.1. In presence of chloride, the constants K_n are smaller because of the formation of chloro complexes and mixed complexes In(SR)_nCl_i(3-n-1)+ and the stability constants of these have also been determined. The constants for the complexes without coordinated chloride can finally be obtained by an extrapolation (Fig. 2). The problem of the influence of increasing charge on the stability of various complexes of the isoelectronic 4d¹⁰ cations is discussed (Fig. 3).     

Persistent current through a semiconductor quantum dot with Gaussian confinement

The persistent diamagnetic current in a GaAs quantum dot with Gaussian confinement is calculated. It is shown that except at very low temperature or at high temperature, the persistent current increases with decreasing temperature. It is also shown that as a function of the dot size, the diamagnetic current exhibits a maximum at a certain confinement length. It is furthermore shown that for a shallow potential, the persistent current shows an interesting maximum structure as a function of the depth of the potential. At low temperature, the peak structure is pretty sharp but becomes broader and broader with increasing temperature.     

A New Approach for in vitro Imaging of Breast Cancer Cells by Anti‐Metadherin Targeted PVA‐Pyrene

Poly(vinyl alcohol)‐pyrene‐anti‐metadherin (PVA‐Py‐(Anti‐MTDH)), a novel antibody based water soluble probe containing both fluorescent and target sites in the structure for in vitro imaging of breast cancer cells is reported here. Since breast cancer cells have an excess of MDTH protein expressed on the surface, a PVA‐Py prepared by “Click chemistry” approach is targeted by Anti‐MTDH antibody and applied to the MCF‐7 cell line. After characterization, the designed architecture was evaluated in terms of cell incorporation efficiency and compared with a non‐targeted structure (PVA‐Py). Atomic force microscopy (AFM) and fluorescence microscopy images of cells after incubation of the probe molecules were also obtained to monitor the interaction of the probes with the cancerous cells.

     

Investigations on the applicability of two ELISA types for the determination of chlorpyrifos in soil samples compared with a gas chromatographic method

Two commercially available ELISA kits for water analysis, a microtiter plate-ELISA based on polyclonal antibodies (p-ELISA) and a magnetic particle tube-ELISA based on monoclonal antibodies (t-ELISA), were used to determine chlorpyrifos residues in soils. Comparison with a gas chromatographic method frequently applied was carried out by fortification experiments and by analyses of real soil samples. At concentration levels of 1.0, 0.1, 0.05 and 0.01 mg/kg, chlorpyrifos was reliably determined by the GC method. Application of the p-ELISA did not permit a reliable quantitation, while the t-ELISA was applicable in a concentration range of 0.05–1.0 mg chlorpyrifos/kg dry soil.     

Investigations on the applicability of two ELISA types for the determination of chlorpyrifos in soil samples compared with a gas chromatographic method

Two commercially available ELISA kits for water analysis, a microtiter plate-ELISA based on polyclonal antibodies (p-ELISA) and a magnetic particle tube-ELISA based on monoclonal antibodies (t-ELISA), were used to determine chlorpyrifos residues in soils. Comparison with a gas chromatographic method frequently applied was carried out by fortification experiments and by analyses of real soil samples. At concentration levels of 1.0, 0.1, 0.05 and 0.01 mg/kg, chlorpyrifos was reliably determined by the GC method. Application of the p-ELISA did not permit a reliable quantitation, while the t-ELISA was applicable in a concentration range of 0.05–1.0 mg chlorpyrifos/kg dry soil. Received: 23 July 1997 / Revised: 10 November 1997 / Accepted: 14 November 1997     

Pilot study: PAH fingerprints of aircraft exhaust in comparison with diesel engine exhaust

In the course of a preliminary investigation the PAH fingerprints from diesel engines were compared with those from aircraft turbines. The goal was to determine whether PAH fingerprints permit to distinguish between the sources of air and road traffic. The results showed that the PAH spectra of both sources do not vary significantly. However, in turbine exhaust gas p-quaterphenyl was found, that is untypical for diesel engines. So this component may be a tracer for PAH pollution from aeroplanes.     

A comparative study on electronic and structural properties of transition metal monosilicides, CrSi(B20-type), RhSi(B20-type), RhSi(B31-type) and RhSi(B2-type)

Transition metal based monosilicide compounds (CrSi and RhSi) have been investigated theoretically from ab initio calculations. The structural and electronic band calculations of CrSi and different phases of RhSi crystals show that the metallic property and hypothetically constructed structures of RhSi(Pnma) under different pressures from 0 GPa to 75 GPa show a certain difference only along Γ–Z directions of the high symmetry points of first Brillouin zone. The character of the bands around fermi level was determined by partial density of state calculations.