Publications by authors named "Marilyn Schneider"

Electron tubes continue to provide the highest speeds possible for recording dynamics of hot high-energy density plasmas. Standard streak camera drive electronics and CCD readout are not compatible with the radiation environment associated with high DT fusion yield inertial confinement fusion experiments >10 14 MeV DT neutrons or >10 n cm ns. We describe a hardened x-ray streak camera developed for the National Ignition Facility and present preliminary results from the first experiment on which it has participated, recording the time-resolved bremsstrahlung spectrum from the core of an inertial confinement fusion implosion at more than 40× the operational neutron yield limit of the previous National Ignition Facility x-ray streak cameras.

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Background: The transition to adulthood involves achievement of objective milestones, yet becoming an adult is also widely considered a subjective experience. Much of the extant research about autistic adulthood focuses on the objective aspects of adulthood, with little emphasis on the subjective experience of adulthood. There is lack of research incorporating the perspectives of autistic youth about preparation for becoming an adult.

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A new configuration based on the recent off-line calibrations of the gated laser entrance hole diagnostic on the National Ignition Facility provides 4-8 interleaved frames per experiment using the standard two frame sensor settings. Since its implementation, the new design has greatly increased the data return for hundreds of experiments at the National Ignition Facility. The large quantity of images from a variety of physics campaigns has revealed information on plasma evolution in hohlraums.

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Twenty dairy cows received flunixin meglumine at 2.2 mg/kg bw, administered once daily by either the intravenous (IV) or intramuscular (IM) route for three consecutive days with either intravenous normal saline (NS) or lipopolysaccharide (LPS) providing a balanced design with five animals per group. Cows were sacrificed after a 4 day withdrawal period, and 13 muscle types were collected and assayed for flunixin by LC-MS/MS.

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A collaborative study was conducted to evaluate the AOAC First Action 2012.25 LC-MS/MS analytical method for the determination of residues of three triphenylmethane dyes (malachite green, crystal violet, and brilliant green) and their metabolites (leucomalachite green and leucocrystal violet) in seafood. Fourteen laboratories from the United States, Canada, and the European Union member states participated in the study including national and state regulatory laboratories, university and national research laboratories, and private analytical testing laboratories.

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Prior to conducting a collaborative study of AOAC First Action 2012.25 LC-MS/MS analytical method for the determination of residues of three triphenylmethane dyes (malachite green, crystal violet, and brilliant green) and their metabolites (leucomalachite green and leucocrystal violet) in seafood, a single-laboratory validation of method 2012.25 was performed to expand the scope of the method to other seafood matrixes including salmon, catfish, tilapia, and shrimp.

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Multiclass, multiresidue methods are becoming increasingly popular in regulatory monitoring programs due to their increased analytical scope and laboratory efficiency. In this work, we report the development and validation of a new high-throughput analytical method to monitor up to 131 veterinary drug residues, representing at least 13 different classes, in bovine muscle. This novel method streamlined sample preparation to <15 min/sample/analyst, or a batch of 40-60 pre-homogenized samples in <3 h/analyst, through the combination of dispersive solid-phase extraction with in-vial filtration (a new technique known as filter-vial d-SPE).

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A simple, cow-side test for the presence of drug residues in live animal fluids would provide useful information for tissue drug residue avoidance programs. This work describes adaptation and evaluation of rapid screening tests to detect drug residues in serum and urine. Medicated heifers had urine, serum, and tissue biopsy samples taken while on drug treatment.

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Enrofloxacin and danofloxacin are the only fluoroquinolone antibiotics approved for use in cattle in the United States. Microbial screening methods commonly used for monitoring veterinary drug residues are not sensitive or selective for fluoroquinolones. In this work, a luminescence-based screening assay was developed to detect fluoroquinolones in beef serum.

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Traditionally, regulatory monitoring of veterinary drug residues in food animal tissues involves the use of several single-class methods to cover a wide analytical scope. Multi-class, multi-residue methods (MMMs) of analysis tend to provide greater overall laboratory efficiency than the use of multiple methods, and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of targeted drug analytes usually provides exceptional performance even for complicated sample extracts. In this work, an LC-MS/MS method was optimized and validated in a test of 120 drug analytes from 11 different classes in bovine kidney.

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In the USA, the US Department of Agriculture's Food Safety and Inspection Service (FSIS) conducts the National Residue Program designed to monitor veterinary drug and other chemical residues in beef and other slaughtered food animals. Currently, FSIS uses a 7-plate bioassay in the laboratory to screen for antimicrobial drugs in bovine kidneys from those animals tested positive by inspectors in the slaughter establishments. The microbial inhibition bioassay has several limitations in terms of monitoring scope, sensitivity, selectivity, and analysis time.

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The U.S. Food and Drug Administration sets tolerances for veterinary drug residues in muscle but does not specify which type of muscle should be analyzed.

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Methods for the analysis of ten selected fluoroquinolone antibiotics in biological fluids are reviewed. Approaches for sample preparation, detection methods, limits of detection and quantitation, and recovery information are provided for both single analyte and multi-analyte fluoroquinolone methods.

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Rapid screening tests can be used as part of an efficient program designed to monitor veterinary drug residues in cattle. In this work, three rapid tests designed to screen samples for the presence of antibiotic residues, the Fast Antimicrobial Screen Test (FAST), Premi and Kidney Inhibition Swab (KIS) tests, were compared using beef kidney juice and serum samples. In order to provide a realistic assessment, potentially incurred samples of beef kidney juice and serum were obtained from 235 carcasses which had been retained by inspectors in a processing plant for further testing.

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An europium-sensitized time-resolved luminescence (TRL) method was developed to determine oxytetracycline (OTC) in cultivated catfish muscle. Extraction of OTC from fish muscle was performed with pH 4.0 ethylenediaminetetraacetic acid (EDTA)-McIlvaine buffer and clean up with hydrophilic-lipophilic balanced copolymer solid phase extraction (SPE) cartridges.

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A simple, rapid fluorescence screening assay was applied to the analysis of beef muscle for danofloxacin at the U.S. tolerance level of 200 ng/g.

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Three microbial inhibition-based screening methods, the fast antimicrobial screening test (FAST), the Premi test, and the kidney inhibition swab (KIS) test, were evaluated using penicillin G, sulfadimethoxine, oxytetracyline, tylosin, danofloxacin, streptomycin, neomycin, and spectinomycin at a range of fortified concentrations in beef kidney juice and beef serum. Each antibiotic was individually tested simultaneously using the different assays in replicate experiments. Detection threshold concentrations for each analyte in each screening assay were determined for the different matrices.

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An efficient multiresidue method was successfully applied to the determination of fluoroquinolones (FQs) in chicken serum. In this method, FQs are extracted from matrix with ammoniacal acetonitrile, and the extracts are defatted and then evaporated. After addition of basic phosphate buffer and filtration, the samples are analyzed by liquid chromatography-fluorescence-mass spectrometry(n) (multiple mass spectrometry; MS(n)).

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Efficient methods are needed for analysis of veterinary drug residues in food. A number of methods are available for single analytes. Multiresidue methods are now increasingly available.

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A multiresidue method has been developed which allows for the simultaneous determination of both fluoroquinolones and tetracyclines in chicken muscle. Samples were extracted with a mix of acetonitrile and 0.1 M citrate, 150 mM MgCl(2), pH 5.

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Antibiotics are used by veterinarians and producers to treat disease and improve animal production. The federal government, to ensure the safety of the food supply, establishes antibiotic residue tolerances in edible animal tissues and determines the target tissues (e.g.

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An efficient multiresidue method for analysis of fluoroquinolones in shrimp has been developed in which quantitation by fluorescence and confirmation by Multiple Stage Mass Spectrometry (MS) is achieved simultaneously. In this method, shrimp tissue is extracted with ammoniacal acetonitrile and the extract is defatted and then evaporated. After dissolution in basic phosphate buffer, fluoroquinolones in the extract are separated by liquid chromatography and quantitated, taking advantage of their intense fluorescence.

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A simple, rapid fluorescence assay was developed for screening both enrofloxacin (ENRO) and tetracyclines in chicken muscle at the U.S. tolerance levels (300 ng/g and 2 microg/g, respectively).

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A simple, rapid fluorescence assay was developed for screening tetracyclines in chicken muscle at the U.S. tolerance level (2 mg/kg).

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