1,721,002 research outputs found
Occurrence of Salmonella and Listeria spp. on retail poultry products in South Italy and comparison of conventional and rapid methods for their detection
No full textSalmonella and Listeria spp. are frequently detected in poultry meats. Conventional isolation and identification methods to detect these microrganisms in food are laborious and time-consuming. In the present study the occurrence of Salmonellae and Listeriae on 362 samples of retail poultry in Caserta, South Italy was evaluated and standard microbiological and rapid methods were compared. Furthermore, the samples were collected and analyzed twice a week, on Monday and Friday to establish their possible variability from storage. Both methods showed a strong contamination of samples by Listeria spp. (about 50% for both methods) with 12% Listeria monocytogenes while the contamination of Salmonella was poorer (14-15%). The two procedures showed a good agreement for the detection of Listeriae while the sensitivity of the Rapid test for Salmonellae was poorer (75%). Data about sampling on Monday and Friday highlighted a significant increase in Listeria spp. at the end of the week
Toxic and genotoxic evaluation of six antibiotics on non-target organisms
No full textThe ecotoxicity of the following six antibiotics on aquatic organisms was investigated: Erythromycin, Oxytetracyclin, Sulfamethoxazole, Ofloxacin, Lincomycin and Clarithromycin. Bioassays were performed on bacteria, algae, rotifers, microcrustaceans and fish to assess acute and chronic toxicity, while SOS Chromotest and Ames test were used to detect the genotoxic potential of the investigated drugs. For risk assessment, the environmental impact was calculated by MEC/PNEC ratio using the available data from the literature regarding their occurrence in the aquatic environment and the toxicity data obtained from the bioassays performed. The ecotoxicological results showed that acute toxicity was in the order of mg/L while, for the chronic data the antibiotics were bioactive at concentrations in the order of μg/L, mainly for the algae. Drugs investigated were one or two order of magnitude less active against rotifers and crustaceans. Ofloxacin was the only genotoxic compound and Sulfamethoxazole, Ofloxacin and Lincomycin were mutagenic. As for environmental risk, the macrolides were found to be the most harmful for the aquatic environment. © 2004 Elsevier B.V. All rights reserved
A multispecies study to assess the toxic and genotoxic effect of pharmaceuticals: Furosemide and its photoproduct
No full textPharmaceutical products for humans and animals, as well as their related metabolites end up in the aquatic environment after use. Recent investigations show that concentrations of pharmaceuticals are detectable in the order of ng/l-μg/l in municipal wastewater, groundwater and also drinking water. Little is known about the effects, and the hazard of long-term exposure to low concentrations of pharmaceuticals for non-target aquatic organisms. This study was designed to assess the ecotoxicity of furosemide, a potent diuretic agent, and its photoproduct in the aquatic environment. Bioassays were performed on bacteria, algae, rotifers and microcrustaceans to assess acute and chronic toxicity, while the SOS Chromotest and the Ames test were utilized to detect the genotoxic potential of the investigated compounds. A first approach to risk characterization was to calculate the environmental impact of furosemide by measured environmental concentration and predicted no effect concentration ratio (MEC/PNEC). To do so we used occurrence data reported in the literature and our toxicity results. The results showed that acute toxicity was in the order of mg/l for the crustaceans and absent for bacteria and rotifers. Chronic exposure to these compounds caused inhibition of growth population on the consumers, while the algae did not seem to be affected. A mutagenic potential was found for the photoproduct compared to the parental compound suggesting that byproducts ought to be considered in the environmental assessment of drugs. The risk calculated for furosemide suggested its harmlessness on the aquatic compartment. © 2005 Elsevier Ltd. All rights reserved
Evaluation of estrogenic activity of alkylphenols by yeast recombinant assay and assessment of their embryotoxicity on Daphnia magna
No full textMany concerns raised recently regarded the environmental safety of alkylphenol polyethoxylate surfactants (APEOs).They are widely used in detergents, paints, herbicides and many other formulated products. It has been estimated that 60% of APEOs ends up in the aquatic environment; they are biodegraded and transformed into alkylphenols, such as nonylphenol and octylphenol that are hydrophobic and tend to accumulate in sediments. In this study we tested representatives of the most environmentally important groups of alkylphenolic compounds through a recombinant yeast bioassay using Saccaromices cerevisiae strain RMY326. The Yeast Estrogen Screen test (YES-test) is based on the DNA sequence of human estrogen receptor α (hER α) and the reporter gene lac-Z expressing the Escherichia coli enzyme β-galactosidase. Furthermore, we assessed the embryotoxicity of these compounds on the crustacean Daphnia magnathrough the well-known ability of alkylphenols to interfere with the metabolic elimination of testosterone. Daphnids (tert-octylphenol and 4-nonylphenol were the most potent (100 times less than 17β-estradiol used as control) with full dose-response curve. These data indicate that the use of recombinant yeast cells is an interesting complement to study the effects of xenobiotics on the response of vertebrate hormone receptors to the studies with test animals or vertebrate cell cultures. Furthermore, the most of APEOs investigated were also found to be embryotoxic. D. magna showed the first effects after three weeks of exposure even if the high concentrations (in the order of mcg/L), at which abnormalities occurred, indicate that environmental concentrations pose no imminent risk
A MULTISPECIES STUDY TO ASSESS THE TOXIC AND GENOTOXIC EFFECT OF PHARMACEUTICALS: FUROSEMIDE AND ITS PHOTOPRODUCT
No full textPharmaceutical products for humans and animals, as well as their related metabolites end up in the aquatic environment
after use. Recent investigations show that concentrations of pharmaceuticals are detectable in the order of ng/l–
lg/l in municipal wastewater, groundwater and also drinking water. Little is known about the effects, and the hazard of
long-term exposure to low concentrations of pharmaceuticals for non-target aquatic organisms.
This study was designed to assess the ecotoxicity of furosemide, a potent diuretic agent, and its photoproduct in the
aquatic environment. Bioassays were performed on bacteria, algae, rotifers and microcrustaceans to assess acute and
chronic toxicity, while the SOS Chromotest and the Ames test were utilized to detect the genotoxic potential of the
investigated compounds.
A first approach to risk characterization was to calculate the environmental impact of furosemide by measured environmental
concentration and predicted no effect concentration ratio (MEC/PNEC). To do so we used occurrence data
reported in the literature and our toxicity results. The results showed that acute toxicity was in the order of mg/l for the
crustaceans and absent for bacteria and rotifers. Chronic exposure to these compounds caused inhibition of growth
population on the consumers, while the algae did not seem to be affected. A mutagenic potential was found for the photoproduct
compared to the parental compound suggesting that byproducts ought to be considered in the environmental
assessment of drugs. The risk calculated for furosemide suggested its harmlessness on the aquatic compartment
Environmental toxicity and genotoxicity of antibiotics on organisms of the aquatic food chain
No full textDrugs are not environmentally different from other chemicals. High quantities of pharmaceuticals are discharged into sewage treatment plants when used for human cure and directly into surface waters or on soil when used for veterinary purposes. Drugs generally occur in low concentrations (ng-g/L) in various compartments of the aquatic environment Though antibacterial agents are known to have irreversible, no quantifiable effects on the gene pool of microrganisms (resistance), few data exist about the disturbance they cause to the wastewater treatment process, the microbial life in surface waters and their effects at low concentrations on other organisms. The ecotoxicity of the following six antibiotics on aquatic organisms was investigated: Erythromycin, Oxytetracyclin, Sulfamethoxazole, Ofloxacin, Lincomycin and Clarithromycin . Bioassays were performed on bacteria, algae, rotifers, microcrustaceans and fish to assess acute and chronic toxicity, while SOS chromotest and Ames test were used to detect the genotoxic potential of the investigated drugs. For risk assessment, the environmental impact was calculated by MEC/PNEC ratio using the available data from the literature regarding the occurrence in the aquatic environment of the pharmaceuticals investigated and the toxicity data obtained from the bioassays performed. The ecotoxicological results showed that acute toxicity was in the order of mg/L while, for the chronic data the antibiotics were bioactive at concentrations in the order of μg/L, mainly for the algae. The toxicity ratios of acute and chronic effect (A/C ratio) ranged for Brachionus calyciflorus from 3 (clarithromycin and sulphametoxazole) to 56 (ofloxacin) and for Ceriodaphnia dubia from 2 (clarithromycin and lincomycin) to 104 (oxytetracyclin), confirming that chronic assays are more appropriate than acute ones to detect the impact of pharmaceuticals. Ofloxacin was the only genotoxic compound and Sulfamethoxazole, Ofloxacin and Lincomycin were mutagenic. As for environmental risk, the macrolides were found to be the most harmful for the aquatic environment
Toxic and genotoxic impact of fibrates and their photoproducts on non-target organisms
No full textLipid regulators have been detected in effluents from sewage treatment plants and surface waters from humans via excretion. This study was designed to assess the ecotoxicity of fibrates, lipid regulating agents. The following compounds were investigated: Bezafibrate, Fenofibrate and Gemfibrozil and their derivatives obtained by solar simulator irradiation. Bioassays were performed on bacteria, algae, rotifers and microcrustaceans to assess acute and chronic toxicity, while SOS Chromotest and Ames test were utilized to detect the genotoxic potential of the investigated compounds. The photoproducts were identified by their physical features and for the first risk evaluation, the environmental impact of parental compounds was calculated by Measured Environmental Concentrations (MEC) using the available data from the literature regarding drug occurrence in the aquatic environment and the Predicted No Effect Concentrations (PNEC) based on our toxicity data. The results showed that acute toxicity was in the order of dozens of mg/L for all the trophic levels utilized in bioassays (bacteria, rotifers, crustaceans). Chronic exposure to these compounds caused inhibition of growth population on rotifers and crustaceans while the algae seemed to be slightly affected by this class of pharmaceuticals. Genotoxic and mutagenic effects were especially found for the Gemfibrozil photoproduct suggesting that also byproducts have to be considered in the environmental risk of drugs. © 2007 Elsevier Ltd. All rights reserved
Legendre quadrature for the discretization of 1D radiating panels
No full textIn [A. Capozzoli, C. Curcio, A. Liseno, MMS, Pizzo Calabro, Italy, 2022], the problem of modeling a source/scatterer using an equivalent radiator has been addressed and an approach has been given and numerically assessed. Once dimensioned the radiating panel, a practical implementation can be provided by a non-uniform array. The element positions should be chosen so that the array is capable to approximate, with an adequate accuracy, the fields radiated by the equivalent radiator. Here, the array element positioning is performed by exploiting a quadrature rule which takes into account that the singular functions supported on the region of interest associated to the most significant singular values of the radiation operator are related to those supported on the equivalent panel by a radiation integral. The quadrature rule enables also to choose a set of weights which are essential in the definition of the element excitation coefficients from the knowledge of the source distribution on the equivalent panel. For simplicity, a one-dimensional problem with a Legendre quadrature rule is considered. The approach is numerically assessed by checking the capability of the array to radiate, with a satisfactory degree of accuracy, the singular functions associated to the region of interest
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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