Search results for "Clad"
showing 10 items of 495 documents
Label-free wavelength and phase detection based SMS fiber immunosensors optimized with cladding etching
2018
The performance of E-SMS (Etched Singlemode-Multimode-Singlemode) optical fiber structures as immunosensors has been assessed by the implementation of antibody/antigen immunoassays. Through this procedure it has been proven that E-SMS structures are effective and suitable optical platforms for label-free biosensing. Using the phase shift and tracking the wavelength response it was found that the fabricated E-SMS devices exhibited limits of detection (LOD) down up to concentrations of 0.2mg/L of antigens in solution. This was achieved by coating the E-SMS with an antibody-based biolayer (goat IgG) that is able to determine the presence of anti-goat IgG antigen. Both a wavelength detection an…
Effect of the lipid regulator Gemfibrozil in the Cladocera Daphnia magna at different temperatures.
2016
ABSTRACTIn the present study, an ecotoxicological approach to the evaluation of Gemfibrozil (GEM) as an emerging organic pollutant was done. In order to assess its toxicity, tests were conducted using the cladocera Daphnia magna. Experiments were carried out at 22°C and 28°C. EC50, feeding behavior, and chronic toxicity tests (21 days) were evaluated in D. magna exposed to GEM as well as cholesterol levels at 21-day chronic exposure. D. magna GEM EC50 values (24 h) in our experimental conditions were 148.75 and 116.24 mg L−1 at 22°C and 28°C, respectively. Test concentrations of 0.1, 0.5, 1.0, 5.0 and 7.5 mg L−1 were selected for subacute and chronic experiments. Subacute short-term test (f…
The toxicity and concentrations of PAHs in creosote-contaminated lake sediment
1999
Sediment samplers, divided into three layers (0 – 10, 10 – 20 and 20 – 30 cm), were collected from 16 sites in Lake Jamsanvesi, Central Finland. The acute toxicity of pore waters and elutriates (sediment + water 1:4 v/v) were studied by bioluminescence inhibition test and by immobilisation of water fleas (Daphnia magna Straus). Concentrations of polycyclic aromatic hydrocarbons (PAHs) in sediments and elutriates were measured by gas chromatography using flame ionization detection (GC/FID). The highest total PAH concentration was 3.3 mg/g dry weight in the sediment and up to 1.7 mg/l in the elutriate of the uppermost (0 – 10 cm) layer, also being the most toxic to photoluminencent bacteria, …
Acute, chronic and sublethal effects of the herbicide propanil on Daphnia magna.
2003
Acute and chronic toxicity tests with propanil were conducted on Daphnia magna. The 24 and 48 h LC50 were 43.74 and 5.01 mg/l respectively. Chronic toxicity tests were carried out using sublethal propanil concentrations (0.07, 0.10, 0.21 and 0.55 mg/l) during 21 days. The effect of propanil on survival, reproduction and growth of D. magna organisms was monitored. The parameters used to evaluate herbicide effect on reproduction were: mean total young ones per female, mean brood size, time to first reproduction, mean number broods per female and intrinsic rate of natural increase (r). Survival and growth (body length) were also determined after 21 days of exposure to the herbicide. Reproducti…
Disturbances in energy metabolism of Daphnia magna after exposure to tebuconazole.
2008
Abstract This study was conducted to investigate the change of some biochemical parameters in the aquatic invertebrate Daphnia magna following exposure to the fungicide tebuconazole and to determine the most sensitive biomarker among the ones tested in this species. Four biochemical biomarkers (protein, glycogen, lipids and caloric content) were correlated with feeding behaviour studies of D. magna after fungicide exposure. Juveniles of D. magna were exposed to four sublethal concentrations of tebuconazole (0.41, 0.52, 0.71 and 1.14 mg L−1) for 5 d. Daphnid samples were taken from each test and control group at 24, 48, 72, 96 and 120 h after the start of the experiment. Tebuconazole EC50 va…
Ecotoxicological studies with the freshwater rotifer Brachionus calyciflorus. Resource competition between rotifers and daphnids under toxic stress
1993
Abstract This study examined the ability of the freshwater rotifer Brachionus calyciflorus to coexist with the large cladoceran Daphnia magna, and the effect of sublethal concentrations of copper on the competition between both species. Preliminary laboratory experiments showed that large Daphnia (> 1.2 mm) can kill and rapidly exclude the rotifer B. calyciflorus in mixed-species cultures. Brachionus populations were suppressed by Daphnia both through exploitative competition for shared, limited food resources and through mechanical interference. At a food concentration of 1 X 105 cells/ml of Nannochloris oculata, competition caused high mortality rates and decreased fertility in the rotife…
Effect of the insecticide methylparathion on filtration and ingestion rates of Brachionus calyciflorus and Daphnia magna
1993
The freshwater rotifer Brachionus calyciflorus and the cladocera Daphnia magna were exposed to sublethal levels of methylparathion to determine the effect on filtration and ingestion rates. The experiments were performed using the unicellular algae, Nannochloris oculata in a density of 5 × 105 cell/ml. Prior to feeding experiments, preliminary acute toxicity tests were carried out to determine 24-h LC50 values for both species, these values indicated that Daphnia magna was more sensitive to methylparathion acute exposure than Brachionus calyciflorus was. Rates of filtration and ingestion declined with increasing methylparathion concentrations after an exposure of 5 h to this toxicant. The e…
Biochemical stress response in tetradifon exposed Daphnia magna and its relationship to individual growth and reproduction
2009
Abstract Environmental risk assessment of chemicals toxicity requires the use of costly and labor-intensive chronic data and short-term tests provide additional information. Energy budget is used by the animals for their growth, reproduction, and metabolism and it is reduced in case of toxic stress. Tetradifon acaricide is frequently used in the European Mediterranean region and it is implicated in aquatic environmental pollution. Previous studies showed that the EC50-24 h of tetradifon on Daphnia magna was 8.92 mg/L. Based on that, D. magna were exposed to sublethal tetradifon concentrations of 0.10, 0.18, 0.22 and 0.44 mg/L for five days in order to investigate their effect on intermediat…
Leaps and bounds: geographical and ecological distance constrained the colonisation of the Afrotemperate by Erica.
2018
Abstract Background The coincidence of long distance dispersal (LDD) and biome shift is assumed to be the result of a multifaceted interplay between geographical distance and ecological suitability of source and sink areas. Here, we test the influence of these factors on the dispersal history of the flowering plant genus Erica (Ericaceae) across the Afrotemperate. We quantify similarity of Erica climate niches per biogeographic area using direct observations of species, and test various colonisation scenarios while estimating ancestral areas for the Erica clade using parametric biogeographic model testing. Results We infer that the overall dispersal history of Erica across the Afrotemperate…
Kretzoiarctos gen. nov., the oldest member of the giant panda clade
2012
The phylogenetic position of the giant panda, Ailuropoda melanoleuca (Carnivora: Ursidae: Ailuropodinae), has been one of the most hotly debated topics by mammalian biologists and paleontologists during the last century. Based on molecular data, it is currently recognized as a true ursid, sister-taxon of the remaining extant bears, from which it would have diverged by the Early Miocene. However, from a paleobiogeographic and chronological perspective, the origin of the giant panda lineage has remained elusive due to the scarcity of the available Miocene fossil record. Until recently, the genus Ailurarctos from the Late Miocene of China (ca. 8–7 mya) was recognized as the oldest undoubted me…