Antimicrobial residues found to be present in milk can have both health and economic impacts. For these reasons, the widespread routine testing of milk is required. Due to delays with sample handling ...and test scheduling, laboratory-based tests are not always suited for making decisions about raw material intake and product release, especially when samples require shipping to a central testing facility. Therefore, rapid on-site screening tests that can produce results within a matter of minutes are required to facilitate rapid intake and product release processes. Such tests must be simple for use by non-technical staff. There is increasing momentum towards the development and implementation of multiplexing tests that can detect a range of important antimicrobial residues simultaneously. A simple in situ multiplexed planar waveguide device that can simultaneously detect chloramphenicol, streptomycin and desfuroylceftiofur in raw dairy milk, without sample preparation, has been developed. Samples are simply mixed with antibody prior to an aliquot being passed through the detection cartridge for 5 min before reading on a field-deployable portable instrument. Multiplexed calibration curves were produced in both buffer and raw milk. Buffer curves, for chloramphenicol, streptomycin and desfuroylceftiofur, showed linear ranges (inhibitory concentration (IC)
20
–IC
80
) of 0.1–0.9, 3–129 and 12–26 ng/ml, whilst linear range in milk was 0.13–0.74, 11–376 and 2–12 ng/ml, respectively, thus meeting European legislated concentration requirements for both chloramphenicol and streptomycin, in milk, without the need for any sample preparation. Desfuroylceftiofur-contaminated samples require only simple sample dilution to bring positive samples within the range of quantification. Assay repeatability and reproducibility were lower than 12 coefficient of variation (%CV), whilst blank raw milk samples (
n
= 9) showed repeatability ranging between 4.2 and 8.1 %CV when measured on all three calibration curves.
Graphical Abstract
MBio SnapEsi reader and cartridge
Isotropic and anisotropic shape‐memory polymer foams are prepared by supercritical carbon dioxide foaming from a multiblock copolymer (PDLCL) consisting of poly(ω‐pentadecalactone) and ...poly(ε‐caprolactone) segments. Analysis by micro‐computed tomography reveals for the anisotropic PDLCL foam cells a high shape anisotropy ratio of R = 1.72 ± 0.62 with a corresponding Young's compression moduli ratio between longitudinal and transversal direction of 4.3. The experimental compression data in the linear elastic range can be well described by the anisotropic open foam model of Gibson and Ashby. A micro‐morphological analysis for single pores using scanning electron microscopy images permits the correlation between the macroscopic stress‐compression behavior and microscale structural changes.
Polymeric foams require high performance values at low foam density. By using supercritical CO2 it is possible to generate highly porous anisotropic foams from shape‐memory polymers. Depending on the pore geometry high energy storage and high shape‐ as well as stress‐recovery properties can be obtained and characterized both by microscopic and macroscopic experimental methods.
Back Cover: In article number 2000730 by Andreas Lendlein and co‐workers, a temperature‐controlled micro‐bench vise is applied to program anisotropic PDLCL foams into a temporary shape and to observe ...their stress‐free recovery upon heating. Differences in the geometry of the pore deformationen along the two axes of the anisotropic system become apparent during deformations. Most pores recover to their original shapes with a considerable reduction in the pore size.
Citation: IFSCC Magazine, 11 (2008) (3) 207–215
Contrary to the skin biological end points used for determination of the sun protection factor and UVA protection factor, generation of excess free ...radicals in skin – mainly reactive oxygen species – is potentially the source of much skin damage and so represents a more general biophysical answer to the effects of sun exposure of different wavelengths. By applying electron spin resonance spectroscopy to human skin biopsies, we determined in previous work a free radical action spectrum covering the ultraviolet and visible light range. Convolution of the action spectrum with sunlight spectral irradiance (280–700nm) showed the importance of visible light in free radical generation. This unexpected finding led us to perform further investigations. Firstly, an existing sun simulator was modified so that its output truly mimics the sun's full spectrum, including visible light. Human skin biopsies were irradiated either by this device or a conventional UV source, confirming our previous calculations: half of the free radicals are generated in the 400–700nm visible wavelength range. Secondly, the visible spectrum of the modified sun simulator was divided into narrow‐band lights using different pairs of short‐ and long‐pass filters. Human skin biopsies impregnated with specific spin traps were exposed to the different narrow‐band lights to identify different types of free radicals. Generation of dangerous radical species like •O2‐, •OH and •CH‐R was observed in different parts of the visible range, confirming the relevance of the free radical action spectrum and its ability to predict skin protection.
Keywords: UV + VIS solar simulator, ex vivo human skin, free radicals, action spectrum, Electron Spin Resonance
Neogen Corp. has developed Veratox for Almond Allergen for use in the quantitative analysis and screening of almond protein residues in food products, such as cookies, crackers, chocolate bars, ...cereals, beverages, and clean-in-place rinses. Quantitation with Veratox for Almond Allergen ranges from 2.5 to 25 ppm and, with dilution, it can be extended for highly positive samples. This paper describes the findings of internal testing and validation studies designed to establish product claims for the assay of Veratox for Almond Allergen.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The photoproduction of η′-mesons off different nuclei has been measured with the CBELSA/TAPS detector system for incident photon energies between 1500–2200 MeV. The transparency ratio has been ...deduced and compared to theoretical calculations describing the propagation of η′-mesons in nuclei. The comparison indicates a width of the η′-meson of the order of Γ=15–25 MeV at ρ=ρ0 for an average momentum pη′=1050 MeV/c, at which the η′-meson is produced in the nuclear rest frame. The inelastic η′N cross section is estimated to be 3–10 mb. Parameterizing the photoproduction cross section of η′-mesons by σ(A)=σ0Aα, a value of α=0.84±0.03 has been deduced.
Three evolutionary sources create 'primary' reactive oxygen species (ROS) and 'secondary' lipid oxygen species (LOS), forming the human body's 'free radical ground state'. We present evidence for the ...existence of a universal free radical threshold value (FRTV), defining the borderline between advantageous and adverse effects of free radicals observed above the free radical ground state. Based on standard vitamin D doses, the calculated amount of ∼3.5 × 10(12) rad/mg ROS/LOS tissue represents the tolerated number of free radicals in skin tissue - defined as FRTV. By means of quantitative ESR x-band spectroscopy, the FRTV was experimentally verified using ex vivo human skin irradiated with ultraviolet + visible (UV + VIS), UVB + UVA and VIS light. In addition, we investigated whether this threshold is also existent in internal organs by extending our experiment to fresh porcine liver. Based on the determination of ROS/LOS below and above the FRTV, ROS > LOS was characterized as beneficial and LOS > ROS as deleterious to the organism, respectively. Results of the experiments using porcine liver confirmed the appearance of the FRTV at radical generation ∼3.5 × 10(12) rad/mg. The relation ROS/LOS before and after the FRTV was consistent with the results determined for the skin. We conclude that the FRTV, theoretically calculated and experimentally confirmed, should be considered as a new 'universal body constant'.
The Validation of Neogen Reveal® Q+ for DON Gray, R Lucas; Kostin, Alex; Anderson, Gabrielle ...
Journal of AOAC International,
01/2020, Letnik:
103, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
Background: Reveal® Q+ for DON is an immunochromatographic test for quantitative determination of deoxynivalenol (DON) in grains. Objective: A study was conducted to validate performance of ...this method for determination of DON in naturally contaminated corn and wheat and in DON-spiked corn/soy blend, soybeans, barley, malted barley, buckwheat, brown rice, sorghum, and distillers dried grain. Methods: In addition to matrix testing, LOD, linearity, selectivity, robustness, and stability/lot-to-lot consistency testing were performed. Results: The LOD was determined to be 0.014 ppm in corn and 0.037 ppm in wheat, and the LOQ 0.042 ppm in corn and 0.11 ppm in wheat. Recovery ranged from 90 to 104% across a range of reference values of 0.5 to 34.5 ppm. Linearity calculation comparing test results with reference values produced R2 values of 0.999 in both matrixes. Internal results with corn and wheat were corroborated in independent laboratory testing. For DON-spiked commodities, mean recovery across a range of DON concentration from 0.5 to 30 ppm ranged from 90 to 109%. Results of selectivity testing showed no cross-reactivity with other mycotoxins and no interference in detection of DON. Reagent lot-to-lot consistency and stability studies showed consistent results across a range of DON levels and established expiration dating for the test of 18 months after manufacture when stored under specified conditions. Conclusions and Highlights: The Reveal Q+ for DON test offers reliable performance as well as the advantages of aqueous sample extraction, procedural simplicity, minimal labor and equipment requirements, and rapid results. Conclusions: The Reveal Q+ for DON test is validated as a Performace Tested Method in Corn, Wheat, and a variety of other grains. Highlights: The test provides rapid results from a simple aqueous extraction and requires minimal labor and equipment.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Neogen Corp. (Lansing, MI) has developed a common aqueous extraction method for the detection of mycotoxins in the ELISA or lateral flow format. The Veratox® for Total Aflatoxin ELISA extraction ...method uses a MAX 2 extraction packet and water in replacement of traditionally used organic solvents. Veratox for Total Aflatoxin has a detection range of 5-50 ppb neat or up to 300 ppb with dilution. The kit development focused on superior cross-reactivity, ability to accurately detect naturally contaminated samples, and utilization of an aqueous extraction method. In two separate validation studies, the Veratox for Total Aflatoxin test kit resulted in average yields of 91-114% in naturally contaminated mycotoxin reference material corn. The cross-reactivity profiles for aflatoxins B1, B2, G1, and G2 were 100, 113, 103, and 93%, respectively. This kit is approved by the Grain Inspection, Packers, and Stockyards Administration.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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