Monitoring of DNA damage in haemocytes of freshwater mussel Sinanodonta woodiana sampled from the Velika Morava River in Serbia with the comet assay

This study was undertaken to investigate the potential of the freshwater mussel Sinanodonta woodiana for detection of genotoxic pollution of the environment. Study was performed at two sites in the Velika Morava River, from May 2010 to February 2011. The alkaline comet assay on haemocytes was used, and the olive tail moment (OTM) was chosen as a measure of DNA damage. The specimens held on acclimation under controlled laboratory conditions for 10 d were used as a control. Chemical analysis revealed the presence of phosphates and increased concentrations of zinc, copper and nickel at both sites during the entire sampling period. The values of OTM in mussels collected from the environment, significantly correlated with the concentration of zinc (r = 0.6248), temperature (r = 0.7006) and dissolved oxygen (r = 0.7738). Seasonal variations in genotoxic response were observed, with the highest OTM values obtained during summer months. Preliminary results of the in vitro study indicated the effect of water temperature on genotoxic response to zinc and cadmium in S. woodiana suggesting that the presence of genotoxic pollutants during months with lower temperature could be under-estimated. Obtained results indicate that S. woodiana could be a valuable tool for active biomonitoring of aquatic environments and emphasizes the importance of seasonal genotoxic monitoring with this organism.     

Determination of O3, NO2, SO2, CO and PM10 measured in Belgrade urban area

O(3), NO(2), SO(2), CO and PM(10) concentrations, simultaneously determined for the first time in Belgrade urban area in the autumnal period of 2005, are presented. The obtained results display similar behaviour of SO(2), NO(2), CO, PM(10) opposite from that of O(3). The weekend effect was also investigated showing diminution of average daily concentrations of SO(2), NO(2), PM(10) and CO for 72, 40, 37 and 42% respectively, and increase of the average daily concentration of O(3) for 56%. Influence of meteorological conditions on observed concentration levels was studied, too. The observed influence of wind speed on the O(3) nightly concentration levels was analyzed pointing to the phenomena of O(3) transport during episodic measurements. To make an identification of possible pollution sources and analyse the influence of meteorological parameters on pollution levels, air back trajectories for high level concentrations episodes were calculated and analysed. A multivariate receptor modelling (Principal Component Analysis, Cluster Analysis) has been applied to a set of data in order to determine the contribution of different sources. It was found that the main principal components, extracted from the air pollution data, were related to gasoline combustion, oil combustion and ozone transport.     

Novel Renewable Polyols Based on Limonene for Rigid Polyurethane Foams

Novel renewable polyols based on limonene were synthesized using thiol-ene “click” chemistry. These limonene based polyols were structurally characterized using wet methods (hydroxyl number, acid value and viscosity), gel permeation chromatography and spectroscopic methods. The results indicated that high yield of polyols from limonene based materials can be obtained using thiol-ene reaction. These limonene based polyols were used successfully for preparation of rigid polyurethane foams. These foams had regular shape cells and uniform cell size distribution. Thermal studies on these foams indicated that foams were thermally stable up to 250 °C. The glass transition temperature of the foams was higher than 200 °C. These rigid polyurethane foams had high compressive strength and the highest compressive strength of 195 kPa was observed. These foams have good physical–mechanical characteristics and could be suitable for all the applications of rigid polyurethane foams such as thermal insulation of freezers, storage tanks for the chemical and food industries, and packing materials for food industries.     

Groundwater chemistry and the Balkan endemic nephropathy

Until now failure has been a common feature of all attempts to elucidate the aetiology of Balkan endemic nephropathy (BEN), a peculiar kidney disease known to exist only in south-eastern Europe. However, whatever the cause, many epidemiological data point to water as a vehicle of the unknown agent(s). We addressed the issue by reexamining multielement hydrogeochemical data obtained by one of us (WME) in the field, as well as other relevant pieces of evidence.Well water samples were obtained from 18 households heavily affected by BEN, and situated in nine villages scattered over six distinct endemic areas. Control samples were taken from non-affected households exposed to the BEN environment (2), as well as from neighbouring non-endemic villages (5).In terms of the chemical composition of well water, considerable differences between the areas were observed. As a rule the water chemistry of BEN-affected households was rather similar to control samples but there were large variations within each of the two groups.Though none of the wide range of geochemical and hydrogeological parameters have been positively implicated as related to BEN, water-borne chemicals still remain a clue to be pursued, particularly in relation to ultratrace concentrations of bioessential elements and organics.     

From Natural Oils to Epoxy Resins: A New Paradigm in Renewable Performance Materials

The direct conversion of natural products to useful engineering materials is desirable from both economic and environmental considerations. We describe the synthesis and properties of 100?% oil-based epoxy resins generated from three epoxidized oils. The catalyst, tris(pentafluorophenyl)borane (B(C₆F₅)₃) in toluene, allowed for controlled cationic polymerization at a very low concentration. Epoxidized oils (derived from triolein, soybean, and linseed oil) had varying epoxy content, rendering resins of different cross-link density. The polymerization was carried out at room temperature followed by post-curing at elevated temperature to speed up conversion. Epoxy resins were amorphous transparent glasses below glass transitions and hard rubbers above. Despite their high cross-link density, these materials show relatively low T_g’s reflecting the aliphatic nature of fatty acids and the presence of plasticizing “dangling” chains. The structure of the triglyceride starting oils influenced the properties of the resulting materials: the more regular structure of triolein compared to the very heterogeneous structures of soybean and linseed oils seemed to have enhanced some properties of the polymer networks. These epoxy polymers are potentially useful as encapsulating and potting compounds for electronic applications.

     

Polyols and Rigid Polyurethane Foams from Cashew Nut Shell Liquid

Cashew nut shell liquid (CNSL) is a natural aromatic oil consisting of a mixture of phenolic structures with a carboxyl group in ortho position and substituted in meta position with a hydrocarbon chain of 15 carbon atoms. The major component of CNSL is anacardic acid (90?%), which is easily decarboxylated to cardanol by distillation. The present work describes the synthesis of new biobased Mannich polyols for rigid polyurethane foams in two steps: synthesis of Mannich bases by reacting phenolic ring of cardanol with N-(2-hydroxyethyl)-1,3-oxazolidine followed by alkoxylation reactions. The polyols were characterized by wet methods (hydroxyl numbers, viscosity, acid value, density, water content, iodine value etc.), spectroscopic methods (FT-IR, ¹H NMR and ¹³C NMR) and by Gel Permeation Chromatography. The Mannich polyols from cardanol are excellent replacements for petrochemical derived Mannich polyols based on nonyl phenol. Cardanol-based polyols were used successfully for the preparation of rigid polyurethane foams of good physical?Cmechanical and fireproofing properties.     

Cadmium and mercury accumulation in European hare (Lepus europaeus): age-dependent relationships in renal and hepatic tissue

A total of 63 European hares have been collected from five Serbian agricultural regions. The hares assayed were divided into four age groups (3–6 months, 12 months, 12–24 months, and 24–36 months) and investigated upon presence at cadmium (Cd) and mercury (Hg) in the kidney and liver. The positive significant correlation (Ps—Pearson’s coefficient) between Cd concentrations in the kidney and liver within age group the 3–6 months was found (Ps?=?0.81, p?p?p?>?0.05). Statistically significant differences were registered between Hg content in the liver of the hares aged 24–36 and 12 months (p?p?>?0.05). The strong statistically significant associations were registered between Cd and Hg content in the liver (Cd L/Hg L) in the age group 3–6 and 12–24 months (Cd L/Hg L, Ps?=?0.94; p?Ps?=?0.91; p?相似文献   

Fungal spore fragmentation as a function of airflow rates and fungal generation methods

The aim of this study was to characterise and quantify the fungal fragment propagules derived and released from several fungal species (Penicillium, Aspergillus niger and Cladosporium cladosporioides) using different generation methods and different air velocities over the colonies. Real time fungal spore fragmentation was investigated using an Ultraviolet Aerodynamic Particle Sizer (UVASP) and a Scanning Mobility Particle Sizer (SMPS). The study showed that there were significant differences (p < 0.01) in the fragmentation percentage between different air velocities for the three generation methods, namely the direct, the fan and the fungal spore source strength tester (FSSST) methods. The percentage of fragmentation also proved to be dependent on fungal species. The study found that there was no fragmentation for any of the fungal species at an air velocity ≤0.4 m s^?1 for any method of generation. Fluorescent signals, as well as mathematical determination also showed that the fungal fragments were derived from spores. Correlation analysis showed that the number of released fragments measured by the UVAPS under controlled conditions can be predicted on the basis of the number of spores, for Penicillium and A. niger, but not for C. cladosporioides. The fluorescence percentage of fragment samples was found to be significantly different to that of non-fragment samples (p < 0.0001) and the fragment sample fluorescence was always less than that of the non-fragment samples. Size distribution and concentration of fungal fragment particles were investigated qualitatively and quantitatively, by both UVAPS and SMPS, and it was found that the UVAPS was more sensitive than the SMPS for measuring small sample concentrations, whilethe results obtained from the UVAPS and SMAS were not identical for the same samples.     

Comparison of light absorption and oxidative potential of biodiesel/diesel and chemicals/diesel blends soot particles

Soot particles,mainly coming from fuel combustion,affect climate forcing through absorbing light and also result in adverse human health outcomes.Though biodiesel or additives blending with diesel was considered environmentally friendly,the understanding on absorbing and oxidative capacity of soot emitted from them are still unclear.The watersoluble organic carbon(WSOC) content,surface chemical structure,light absorption and oxidative potential(OP^DTT) of soot from biodiesel/diesel and...