Feed coals and fly ashes collected from each row of ESP of Russe TPP were characterized with respect to their Hg content, geochemical and mineralogical compositions. In comparison with all studied ...coals and FAs from other Bulgarian TPPs the present one can be characterized by very low-mercury content. The distribution FA pattern shows that the concentration of Hg consecutive increase from the 1st toward the 3rd ESP row, i.e. the Hg amount is the lowest in the coarsest FAs and the highest in the finest FA fraction. The low Hg concentration may be due to the nature of feed coals, which are bituminous, with very low sulphur content and it is known that the Hg in such high-rank coals is preferably connected with the sulphide minerals. The minerals in coals are mainly quartz, illite, and calcite. The major phases of FAs include glass, quartz, and illite, while hematite, magnetite, anhydrite and mullite are present in minor amount. Hence, the FAs are enriched in some typical inorganic sorbents such as clay minerals, anhydrite, and magnetite-hematite, and, despite the obvious preferable association of Hg with FA char, some Hg capture could also be attributed to these minerals. The geochemical data show an extremely high enrichment of Au (up to 37 times greater than the Clarke value) in studied FAs. The other elements which have an increased concentration are Cd, Be, Se, Ag and Mn, and partially Zr, Ga, Ba, Cs, Ni and Hf. The Hg has positive correlations with O, C, total S, moisture, sulphide and sulphate S content. The data indicate that char, mostly enriched in C has a leading role for the partial capture and retention behaviour of Hg in studied FAs, but total and sulphide S also have a contribution to some extent.Key words: Hg content, chemical composition, coals and fly ashes, Russe TPPAbbreviations: TPP--thermoelectric power plant; ESP--electrostatic precipitator; FA--fly ash; T--temperature; EDF--enrichment/depletion factor
Complexes of cerium(III) with bis(4-hydroxy-2-oxo-2
H-chromen-3-yl)-pyridin-2-yl-methane, bis(4-hydroxy-2-oxo-2
H-chromen-3-yl)-pyridin-3-yl-methane and bis(4-hydroxy-2-oxo-2
...H-chromen-3-yl)-pyridin-4-yl-methane were synthesized by reaction of cerium(III) salt and the ligands, in amounts equal to metal–ligand molar ratio of 1:2. The cerium(III) complexes with bis-coumarins were characterized by different physicochemical methods – elemental analysis, IR-, Raman-,
1H NMR- and
13C NMR-spectroscopy and mass-spectral data. The spectral data of cerium(III) complexes were interpreted on the basis of comparison with the spectra of the free ligands. This analysis showed that in the Ce(III) complexes the ligands coordinated to the metal ion through both deprotonated hydroxyl groups. On the basis of the
ν(C
O) red shift observed, participation of the carbonyl groups in the coordination to the metal ion was also suggested. Cytotoxic screening by MTT assay was carried out. In the present study we performed comparative evaluation of the cytotoxic effects of the three newly synthesized cerium complexes against the acute myeloid leukemia derived HL-60 and the chronic myeloid leukemia (CML)-derived BV-173. In addition the cytotoxic effects of Ce(III) complex with bis(4-hydroxy-2-oxo-2
H-chromen-3-yl)-pyridin-2-yl-methane were evaluated on the SKW-3 cells. In order to elucidate some of the mechanistic aspects of the observed cytotoxic effects we evaluated the ability of this complex to trigger programmed cell death (apoptosis by means of agarose gel electrophoretic analysis of DNA, isolated from the cytosolic fraction of treated SKW-3 cells). In addition, microscopic morphological evaluation of the treated cells was carried out in order to establish morphological features indicative of programmed cell death.
Ce(III) complexes with bis-coumarins were synthesized and characterized by elemental analysis, mass spectrometry,
1H NMR- and
13C NMR-, IR- and Raman-spectroscopy. The complexes revealed cytotoxic activity on HL-60 and BV-173 myeloid cells. The ability of the most active complex to trigger programmed cell death was evaluated.
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In this paper we have studied the rise and decay time responses of Eu and Dy doped strontium aluminates prepared by different methods. The spectrum was characterized by 3D excitation emission ...matrices (EEM). The normalized rise and decay responses of the total power and at two wavelengths on either side of the spectral maximum exhibit individual behavior. We show that the individual switch on and switch off time responses can be approximated by power law and logarithmic dependencies. The relation between spectral and time responses and the sample contents and technology of fabrication is commented.
•Eu and Dy doped strontium aluminates fabricated using different methods with similar 3D spectra.•The experimental study of both Switch ON and Switch OFF spectral and time responses.•Time rise and time decay responses can be entirely or partially fit by power law and logarithmic functions.•All samples exhibit spectrally dependent time responses.•Eu, Dy doped samples exhibit stronger spectral dependences for both rise and fall responses.
The first thorough study of PAHs in feed coals and FAs from combustion in six Bulgarian TPPs was done. Since coal-derived FAs are applied to many targets, it is imperative to enhance the knowledge ...for their geochemical composition and environmental impact. The gap of information on PAHs in feed coals and coal-derived FAs has outlined the aim of the study: (i) to compare by geochemical proxy PAHs in feed coals and FAs generated in six Bulgarian TPPs; (ii) to track the changes in PAHs compositions with feed coal ranks and in different ESP rows; and (iii) to estimate the potential toxicity of FAs (if any). Extractable organic matter (EOM) was prepared. PAHs were isolated in aromatic fractions and quantified in μg/kg. The total PAHs for lignite feed coal are in the range 400–530 μg/kg and for FAs 0.30–12.60 μg/kg: for subbituminous feed coal, they are 4000 μg/kg, and for FAs, 1.10–32.50 μg/kg. For bituminous feed coals, they are - 860 μg/kg and 9305 μg/kg, and for FAs from both TPPs, they are several times lower, from 69.4 μg/kg to 103.3 μg/kg, for the five ESP rows of Varna TPP and from 100.4 to 182.20 μg/kg, for the three rows of ESPs of Russe TPP. The EOM for low rank feed coals is strongly dominated by coal biomarkers, i.e., perylene and phenyl substituted PAHs. Therefore, calculations and ratios based on PAHs compositions are done only for bituminous feed coals and their FAs. Combustion has resulted in a regular shift to lighter PAHs compared to the signature PAHs of feed coals. PAHs distributions in FAs are dominated by phenanthrene. Distribution profiles according to the number of aromatic cycles (R) in PAHs are dominated by three-ring (3R) PAHs > four-ring (4R) PAHs. Only in the last row of ESP from the Varna TPP is there evidence for the presence of heavier PAH, five-ring (5R) benzog,h,ifluoranthene, trapped by the finest particulate matter. Relatively low PAHs concentrations determined for FAs are compared with the values for PAHs in soils according to the Bulgarian regulation.
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•Comparative study of PAHs in different rank feed coals and fly ashes from six TPPs.•PAHs in fly ashes range from 0.3 μg/kg to 182.2 μg/kg, depend on the feed coal rank.•Apparent shift to low molecular weight PAHs (3R, 4R) in FAs compared to feed coals.•Low rank feed coals distribution pattern dominated by native, non-carcinogenic PAHs.•Proof of higher molecular PAH in the finest particles of electrostatic precipitator.
In this paper we study the effect of temperature on the rise and decay time responses of Eu and Eu, Dy doped strontium aluminates. Normalized switch on and switch off time responses are used to ...estimate the share of phosphorescence in the observed luminescence. The parameters of the power law time responses related to the relative share of phosphorescence in luminescence and to the rise/decay rates are found to be strongly temperature dependent. The results show that unlike luminescence intensity, the overall efficiency of phosphorescence increases strongly with temperature and reaches a maximum around 65 °C. Thе maximum correlates with the activation energy of the samples and depends on their doping and fabrication technology.
•Effects of temperature on Eu and Dy doped strontium aluminates fabricated using different methods.•The experimental study of temperature dependence of Switch ON and Switch OFF time responses.•The parameters of the power law fits of time responses found to be strongly temperature dependent.•The relative part of phosphorescence in luminescence is highly temperature dependent.•The overall phosphorescence efficiency is defined and its temperature dependence is measured.
Nanoparticles (NPs) in different forms have been widely used in medicine and pharmaceutics for diagnosis and drug delivery. So, they are in intimate contact with bio-macromolecules like proteins ...which are vital and functional elements of cells and organisms. Thus,
in vitro
studies of the possible interaction between proteins and NPs are necessary from both application and toxicity points of view. In this article, binding characteristics and protein conformational change through interaction with various NPs have been reviewed. In recent years, a wide variety of biophysical techniques have been exploited to elucidate mechanistic aspects of NP-protein interactions. This study has focused on the information acquired from prevalent techniques including fluorescence quenching, synchronous fluorescence spectroscopy, circular dichroism (CD), and surface-enhanced Raman scattering (SERS).
Nanoparticles (NPs) in different forms have been widely used in medicine and pharmaceutics for diagnosis and drug delivery.
The study fills the informative gap on occurrence, distribution, and carcinogenicity of polycyclic aromatic hydrocarbons (PAHs) in Bulgarian coals. It presents quantitative data for content and ...carcinogenicity of PAHs in different rank raw coals from eight basins with geological age from Late Carboniferous to Late Miocene, Ro=0.17–5.20%. The high amounts of alkylated naphthalene and alkylated phenanthrene determined in the bituminous coals reflect the diagenetic conversion of the plant-derived terpenoids into alkylated PAHs.
In this first systematic study of PAHs in Bulgarian raw coals three concentration ranges are established: for Miocene/Eocene age coal – from 1.08 mg/kg to 5.79 mg/kg; for Late Cretaceous/Late Carboniferous age coal – from 77.9 mg/ kg to 137.2 mg/kg; and, for the Late Carboniferous coal – 1.85 mg/kg. The relationship of the total PAHs content vs. raw coal Ro shapes as a “bell” and matches with the published data for the native PAHs from all over the world provenance. The maximal PAHs amount of 137.2 mg/kg at Ro =0.96% for the Late Cretaceous coal lies within the “oil-generation window”, Ro =0.5–1.3% for the kerogen. For all raw coal studied relatively low carcinogenicity is determined based on the well correlated values for BaPeq and TEQ parameters.
The application of inorganic chemistry to medicine is a rapidly developing field, and novel therapeutic and diagnostic metals and metal complexes are now having an impact on medical practice. ...Advances in biocoordination chemistry are crucial for improving the design of compounds to reduce toxic side effects and understand their mechanisms of action. A lot of metal-based drugs are widely used in the treatment of cancer. The clinical success of cisplatin and other platinum complexes is limited by significant side effects acquired or intrinsic resistance. Therefore, much attention has focused on designing new coordination compounds with improved pharmacological properties and a broader range of antitumor activity. Strategies for developing new anticancer agents include the incorporation of carrier groups that can target tumor cells with high specificity. Also of interest is to develop complexes that bind to DNA in a fundamentally different manner than cisplatin, in an attempt to overcome the resistance pathways that have evolved to eliminate the drug. This review focuses on recent advances in developing lanthanide anticancer agents with an emphasis on lanthanide coordination complexes. These complexes may provide a broader spectrum of antitumor activity. They were compared with classical platinum anticancer drugs. Lanthanides are also of interest because of their therapeutic radioisotopes. The dominant pharmacological applications of lanthanides are as agents in radioimmunotherapy and photodynamic therapy.
Mercury capture by coal-combustion fly ash is a function of the amount of Hg in the feed coal, the amount of carbon in the fly ash, the type of carbon in the fly ash (including variables introduced ...by the rank of the feed coal), and the flue gas temperature at the point of ash collection. In their discussion of fly ash and Hg adsorption, Lu et al. Energy Fuels 2007, 21, 2112−2120 had some fundamental flaws in their techniques, which, in turn, impact the validity of analyzed parameters. First, they used mechanical sieving to segregate fly ash size fractions. Mechanical sieving does not produce representative size fractions, particularly for the finest sizes. If the study samples were not obtained correctly, the subsequent analyses of fly ash carbon and Hg cannot accurately represent the size fractions. In the analysis of carbon forms, it is not possible to accurately determine the forms with scanning electron microscopy. The complexity of the whole particles is overlooked when just examining the outer particle surface. Examination of elements such as Hg, present in very trace quantities in most fly ashes, requires careful attention to the analytical techniques.
