Electrochemical determination of nitroaromatic explosives at boron-doped diamond/graphene nanowall electrodes: 2,4,6-trinitrotoluene and 2,4,6-trinitroanisole in liquid effluents.

The study is devoted to the electrochemical detection of trace explosives on boron-doped diamond/graphene nanowall electrodes (B:DGNW). The electrodes were fabricated in a one-step growth process using chemical vapour deposition without any additional modifications. The electrochemical investigations were focused on the determination of the important nitroaromatic explosive compounds, 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitroanisole (TNA). The distinct reduction peaks of both studied compounds were observed regardless of the pH value of the solution. The reduction peak currents were linearly related to the concentration of TNT and TNA in the range from 0.05-15 ppm. Nevertheless, two various linear trends were observed, attributed respectively to the adsorption processes at low concentrations up to the diffusional character of detection for larger contamination levels. The limit of detection of TNT and TNA is equal to 73 ppb and 270 ppb, respectively. Moreover, the proposed detection strategy has been applied under real conditions with a significant concentration of interfering compounds - in landfill leachates. The proposed bare B:DGNW electrodes were revealed to have a high electroactive area towards the voltammetric determination of various nitroaromatic compounds with a high rate of repeatability, thus appearing to be an attractive nanocarbon surface for further applications.

Concentration and sources of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in surface soil near a municipal solid waste (MSW) landfill.

Due to a continuous demand of land for infrastructural and residential development there is a public concern about the condition of surface soil near municipal solid waste landfills. A total of 12 surface (0-20 cm) soil samples from a territory near a landfill were collected and the concentration of 16 PAHs and 7 PCB congeners were investigated in these samples. Limits of detection were in the range of 0.038-1.2 µg/kg for PAHs and 0.025-0.041 µg/kg for PCBs. The total concentration of ∑ PAHs ranged from 892 to 3514 µg/kg with a mean of 1974 µg/kg. The total concentration of ∑ PCBs ranged from 2.5 to 12 µg/kg with a mean of 4.5 µg/kg. Data analyses allowed to state that the PAHs in surface soils near a landfill were principally from pyrogenic sources. Due to air transport, PAHs forming at the landfill are transported outside the landfill. PCB origin is not connected with the landfill. Aroclor 1242 can be the source of PCBs in several samples.

Recombinant protein kinase C-gamma phorbol binding domain upon microinjection blocked insulin-induced maturation of Xenopus laevis oocytes.

The second cysteine-rich (Cys-2) domain of rat brain PKC-gamma regulatory region C1 (92-173) was expressed in Escherichia coli cells and purified. NMR studies of Cys-2 protein identified the phorbol and other phospholipid binding sites within this molecule (Xu, R.X., Pawelczyk, T., Xia, T-H. and Brown, S.T. (1997) Biochemistry 37, 10709-10717). Here, we tested the ability of this domain to bind other proteins. Using an overlay assay we show that the Cys-2 domain binds other proteins in Xenopus oocyte soluble fraction. Unlike the kinase activity, binding of Cys-2 to other proteins was detected in the absence of added phospholipids. Microinjection of Cys-2 protein into Xenopus leavis oocytes inhibited insulin-induced but not progesterone-induced maturation. The smallest dose that enhanced insulin-induced maturation was 0.45 x 10(-12) mol injected Cys-2. These results demonstrate that the PKC-gamma Cys-2 domain beside being the binding site for phorbol ester/DAG and phosphatidylserine binds also other proteins. The proteins that interact with Cys-2 domain of PKC are essential for insulin-induced maturation program in oocytes.

p53 codon 72 polymorphism in cervical cancer patients and healthy women from Poland.

A polymorphism at codon 72 of gene p53 results in the presence of either arginine or proline at this position. We investigated the distribution of p53 codon 72 polymorphism in cervical cancer patients and a control group of healthy women from Poland. Our results do not confirm the hypothesis that the p53 codon polymorphism could play a role as a factor for squamous carcinoma of the cervix.