59 research outputs found
Infrared Resonance Enhanced Multiphoton Ionization of Fullerenes
Gas-phase fullerenes are resonantly heated by a train of high power subpicosecond pulses from a free electron laser (FEL) to internal energies at which they efficiently undergo delayed ionization. When the laser is tuned from 6â20ÎŒm while the amount of laser produced parent ions is recorded, resonant absorption of 200â600 IR photons, resulting in almost fragmentation-free ion spectra, is observed. Infrared resonance enhanced multiphoton ionization with a FEL is shown to enable extremely sensitive IR spectroscopy with mass selective detection of gas-phase fullerenes
Allergic sensitization: screening methods
Experimental in silico, in vitro, and rodent models for screening and predicting protein sensitizing potential are discussed, including whether there is evidence of new sensitizations and allergies since the introduction of genetically modified crops in 1996, the importance of linear versus conformational epitopes, and protein families that become allergens. Some common challenges for predicting protein sensitization are addressed: (a) exposure routes; (b) frequency and dose of exposure; (c) dose-response relationships; (d) role of digestion, food processing, and the food matrix; (e) role of infection; (f) role of the gut microbiota; (g) influence of the structure and physicochemical properties of the protein; and (h) the genetic background and physiology of consumers. The consensus view is that sensitization screening models are not yet validated to definitively predict the de novo sensitizing potential of a novel protein. However, they would be extremely useful in the discovery and research phases of understanding the mechanisms of food allergy development, and may prove fruitful to provide information regarding potential allergenicity risk assessment of future products on a case by case basis. These data and findings were presented at a 2012 international symposium in Prague organized by the Protein Allergenicity Technical Committee of the International Life Sciences Instituteâs Health and Environmental Sciences Institute
Optical creation of vibrational intrinsic localized modes in anharmonic lattices with realistic interatomic potentials
Using an efficient optimal control scheme to determine the exciting fields,
we theoretically demonstrate the optical creation of vibrational intrinsic
localized modes (ILMs) in anharmonic perfect lattices with realistic
interatomic potentials. For systems with finite size, we show that ILMs can be
excited directly by applying a sequence of femtosecond visible laser pulses at
THz repetition rates. For periodic lattices, ILMs can be created indirectly via
decay of an unstable extended lattice mode which is excited optically either by
a sequence of pulses as described above or by a single picosecond far-infrared
laser pulse with linearly chirped frequency. In light of recent advances in
experimental laser pulse shaping capabilities, the approach is experimentally
promising.Comment: 20 pages, 7 eps figures. Accepted, Phys. Rev.
Current challenges facing the assessment of the allergenic capacity of food allergens in animal models
Food allergy is a major health problem of increasing concern. The insufficiency of protein sources for human nutrition in a world with a growing population is also a significant problem. The introduction of new protein sources into the diet, such as newly developed innovative foods or foods produced using new technologies and production processes, insects, algae, duckweed, or agricultural products from third countries, creates the opportunity for development of new food allergies, and this in turn has driven the need to develop test methods capable of characterizing the allergenic potential of novel food proteins. There is no doubt that robust and reliable animal models for the identification and characterization of food allergens would be valuable tools for safety assessment. However, although various animal models have been proposed for this purpose, to date, none have been formally validated as predictive and none are currently suitable to test the allergenic potential of new foods. Here, the design of various animal models are reviewed, including among others considerations of species and strain, diet, route of administration, dose and formulation of the test protein, relevant controls and endpoints measured
Assessment of transfemoral amputees using a passive microprocessor-controlled knee versus an active powered microprocessor-controlled knee for level walking
Shedding new light on thermionic electron emission of fullerenes
Contains fulltext :
98985.pdf (publisher's version ) (Open Access
Characterisation of the rat ulna compression model using microCT scans and animal-specific Finite Element calculations
status: publishe
Growth and characterisation of single crystals of ternary chalcogenides for laser applications
Bulk single crystals up to 20 mm in diameter and 40 mm long for LiInS2 and up to 10 mm, 20 mm, respectively, for LiInSe2 have been grown. Their colour changed from colourless to rose for the first one and from yellow to dark red for the other All crystals have wurtzite-type lattice (Pna2(1) space group), lattice parameters were determined. A band gap was found to be 3.72 and 3.57 eV for LiInS2 and 3.02, 2.86 eV for LiInSe2 at 80 and 300 K, respectively. Colour variations are due to point defects, first of all to interstitial sulfur; resulting in additional wide absorption bands in the shortwave part of transparency range. For LiInS2 the SHG phase matching conditions were found to be similar for samples of different colour and some difference from Boyd\u27s predictions of 1973 was shown: for XY plane Delta phi similar to +3 degrees at 2.6 mum and Delta phi similar to +3 to -5 degrees at 4-5 mum. Nonlinear susceptibility for LiInS2 was estimated: d(eff)(XY) similar to3.4 pm/V relative to Boyd\u27s valise as 10.6 pm/V A proper illumination gives a photoinduced change of LiInSe2 colour from dark red to yellow as a result of changes in point defects charge state
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