423 research outputs found

    Residues and dissipation kinetics of two imidacloprid nanoformulations on bean (Phaseolus vulgaris L.) under field conditions

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    The current study investigates the dissipation kinetics of two imidacloprid (IMI) nanoformulations (entitled: Nano-IMI and Nano-IMI/TiO2) on common bean (Phaseolus vulgaris) seeds under field conditions and compares them with 35% Suspension Concentrate (SC) commercial formulation. To do so, it sprays P. vulgaris plants at 30 and 60 g/ha within green bean stage, sampling them during the 14-day period after the treatment. Following extraction and quantification of IMI residues, dissipation data have been fitted to simple-first order kinetic model (SFOK) and to first-order double-exponential decay (FODED) models, with 50% and 90% dissipation times (DT50 and DT90, respectively) assessed along the pre-harvest interval (PHI). With the exception of Nano-IMI at 60 g/ha, other decline curves are best fitted to the FODED model. In general, dissipation is faster for Nano-IMI (at 30 g/ha: DT50 = 1.09 days, DT90 = 4.30 days, PHI = 1.23 days; at 60 g/ha: DT50 = 1.29 days, DT90 = 4.29 days, PHI = 2.95 days) and Nano-IMI/TiO2 (at 30 g/ha: DT50 = 1.15 days, DT90 = 4.40 days, PHI = 1.08 days; at 60 g/ha: DT50 = 0.86 days, DT90 = 4.92 days, PHI = 3.02 days), compared to 35% SC (at 30 g/ha: DT50 = 1.58, DT90 = 6.45, PHI = 1.93; at 60 g/ha: DT50 = 1.58 days, DT90 = 14.50 days, PHI = 5.37 days). These results suggest the suitability of Nano-IMI and Nano-IMI/TiO2 application at both rates in terms of their residues on P. vulgaris seeds

    Acute and subchronic dermal toxicity of nanosilver in guinea pig

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    Silver has been used as an antimicrobial agent for a long time in different forms, but silver nanoparticles (nanosilver) have recently been recognized as potent antimicrobial agents. Although nanosilver is finding diverse medical applications such as silver-based dressings and silver-coated medical devices, its dermal and systemic toxicity via dermal use has not yet been identified. In this study, we analyzed the potential toxicity of colloidal nanosilver in acute and subchronic guinea pigs. Before toxicity assessments, the size of colloidal nanosilver was recorded in sizes <100 nm by X-ray diffraction and transmission electron microscopy. For toxicological assessments, male guinea pigs weighing 350 to 400 g were exposed to two different concentrations of nanosilver (1000 and 10,000 ÎŒg/mL) in an acute study and three concentrations of nanosilver (100, 1000, and 10,000 ÎŒg/mL) in a subchronic study. Toxic responses were assessed by clinical and histopathologic parameters. In all experimental animals the sites of exposure were scored for any type of dermal toxicity and compared with negative control and positive control groups. In autopsy studies during the acute test, no significant changes in organ weight or major macroscopic changes were detected, but dose-dependent histopathologic abnormalities were seen in skin, liver, and spleen of all test groups. In addition, experimental animals subjected to subchronic tests showed greater tissue abnormalities than the subjects of acute tests. It seems that colloidal nanosilver has the potential to provide target organ toxicities in a dose- and time-dependent manner

    Fluorescent Polymer—Single‐Walled Carbon Nanotube Complexes with Charged and Noncharged Dendronized Perylene Bisimides for Bioimaging Studies

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    Fluorescent nanomaterials are expected to revolutionize medical diagnostic, imaging, and therapeutic tools due to their superior optical and structural properties. Their inefficient water solubility, cell permeability, biodistribution, and high toxicity, however, limit the full potential of their application. To overcome these obstacles, a water‐soluble, fluorescent, cytocompatible polymer—single‐walled carbon nanotube (SWNT) complex is introduced for bioimaging applications. The supramolecular complex consists of an alkylated polymer conjugated with neutral hydroxylated or charged sulfated dendronized perylene bisimides (PBIs) and SWNTs as a general immobilization platform. The polymer backbone solubilizes the SWNTs, decorates them with fluorescent PBIs, and strongly improves their cytocompatibility by wrapping around the SWNT scaffold. In photophysical measurements and biological in vitro studies, sulfated complexes exhibit superior optical properties, cellular uptake, and intracellular staining over their hydroxylated analogs. A toxicity assay confirms the highly improved cytocompatibility of the polymer‐wrapped SWNTs toward surfactant‐solubilized SWNTs. In microscopy studies the complexes allow for the direct imaging of the SWNTs' cellular uptake via the PBI and SWNT emission using the 1st and 2nd optical window for bioimaging. These findings render the polymer‐SWNT complexes with nanometer size, dual fluorescence, multiple charges, and high cytocompatibility as valuable systems for a broad range of fluorescence bioimaging studies

    Guidance for the design and reporting of studies evaluating the clinical performance of tests for present or past SARS-CoV-2 infection

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    Testing for SARS-CoV-2 infection is key in managing the current pandemic. More than 1700 preprints and peer reviewed journal articles evaluating tests for SARS-CoV-2 infection have been published as of January 2021. However, evaluations of these studies have identified many methodological issues, leading to a high risk of bias and difficulties applying the results in practice. Better guidance is urgently needed on the conduct and interpretation of these studies. This article outlines the principles for defining the intended purpose of the test; study population selection; reference standard, test timing; and other critical considerations for the design, reporting, and interpretation of diagnostic accuracy studies. The implementation and accuracy of SARS-CoV-2 tests have major implications for individuals and communities, balancing the potential consequences of continued infection against the need for public health measures, such as the restriction of movements and social activities. Decision making in the current pandemic requires a clear understanding of the clinical performance and limitations of testing. This article provides guidance to assist researchers design robust diagnostic accuracy studies, assist publishers and peer reviewers to assess such studies, and support clinicians and policy makers in their evaluation of the evidence on SARS-CoV-2 testing for clinical and public health decisions. The guidance aims to ensure that studies evaluating the diagnostic accuracy of SARS-CoV-2 tests are conducted as rigorously as possible, in an efficient and timely way

    Saliency Benchmarking Made Easy: Separating Models, Maps and Metrics

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    Dozens of new models on fixation prediction are published every year and compared on open benchmarks such as MIT300 and LSUN. However, progress in the field can be difficult to judge because models are compared using a variety of inconsistent metrics. Here we show that no single saliency map can perform well under all metrics. Instead, we propose a principled approach to solve the benchmarking problem by separating the notions of saliency models, maps and metrics. Inspired by Bayesian decision theory, we define a saliency model to be a probabilistic model of fixation density prediction and a saliency map to be a metric-specific prediction derived from the model density which maximizes the expected performance on that metric given the model density. We derive these optimal saliency maps for the most commonly used saliency metrics (AUC, sAUC, NSS, CC, SIM, KL-Div) and show that they can be computed analytically or approximated with high precision. We show that this leads to consistent rankings in all metrics and avoids the penalties of using one saliency map for all metrics. Our method allows researchers to have their model compete on many different metrics with state-of-the-art in those metrics: "good" models will perform well in all metrics.Comment: published at ECCV 201

    Multiview classification and dimensionality reduction of scalp and intracranial EEG data through tensor factorisation

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    Electroencephalography (EEG) signals arise as a mixture of various neural processes that occur in different spatial, frequency and temporal locations. In classification paradigms, algorithms are developed that can distinguish between these processes. In this work, we apply tensor factorisation to a set of EEG data from a group of epileptic patients and factorise the data into three modes; space, time and frequency with each mode containing a number of components or signatures. We train separate classifiers on various feature sets corresponding to complementary combinations of those modes and components and test the classification accuracy of each set. The relative influence on the classification accuracy of the respective spatial, temporal or frequency signatures can then be analysed and useful interpretations can be made. Additionaly, we show that through tensor factorisation we can perform dimensionality reduction by evaluating the classification performance with regards to the number mode components and by rejecting components with insignificant contribution to the classification accuracy

    Guidelines for the use and interpretation of assays for monitoring autophagy (2nd edition)

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    In 2008 we published the first set of guidelines for standardiz- ing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new tech- nologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in differ- ent organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes..

    Studying native fishes in Hamadan province

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    Studying native fishes of Hamadan province have been done in 159 stations from 51 important water resources (wetland, reservoir, spring, river and qanat) using with electric tool, cast-net, seine and gill-net gears from July 2010 to Oct. 2011 and the main aims were species identifying and determining their distribution and abundance in the studied area. In the study, 33411 fish specimens are caught in 257 times of sampling and selected randomly about 8500 individual and laboratory works showed the fish belong to 37 species from 7 families. Cyprinidae with 25, Nemacheilidae with 6 and Sisoridae with 2 species had the most diversity and Cobitidae, Poeciliidae, Salmonidae and Mastacembelidae had only a representative. 31 fish species were native or endemic and 6 species were alien. Fish species existed in all rivers of Ghezelozan and Sirvan sub-basins but there were not any fish in 10 rivers of Ghara-Chai sub-basin and in 6 rivers of Gamasiab sub-basin, too. Also, it was observe 1-3 fish species in 15 rivers, 4-6 fish species in 10 rivers, 7-10 fish species in 5 rivers and more than 10 fish species in 4 main water resources and Gamasiab sub-basin with 32 fish species was the most diversified and Ghezelozan sub-basin with 2 fish species was the least diversified. There were any species to 4 (mostly 1 or 2) fish species in studied qanats in Ghara-Chai and Gamasiab rivers sub-basins. 23 fish species existed in a subbasin, 12 species in 2 sub-basin, Capoeta capoeta in 3 sub-basin and Squalius cephalus in all sub-basins of studied area. Alburnoides nicolausi,Capoeta aculeata and Alburnus mossulensis have had the most frequency. Studying fish abundance showed Oxynoemacheilus argyrogramma with 17.8%, Garra rufa with 12.3%, A. mossulensis with 12.1% and C. aculeata with 10.2 % of total number of caught fish specimens are dominant. S. cephalus, Capoeta damascina, C. aculeata, C. trutta, Chondrostoma regium and A. mossulensis have had sport fishing value but Acanthobrama marmid, Oxynoemacheilus kiabii, Oxynoemacheilus kermanshahensis, Turcinoemacheilus kosswigi, Alburnus caeruleus and Mastacembelus mastacembelus have biodiversity value for being endemic or having limited habitats in Iran
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