Effect of mineral composition on thermoluminescence detection of irradiated seafood

Data from import control of irradiated seafood were collected from 300 batches of seafood. Thermoluminescence (TL) analysis of the seafood, based on measurement of thermoluminescent minerals separated from intestinal tract, was carried out with a Risø TL-DA-10 instrument. As identified by X-ray diffraction and SEM/EDS analysis, four main categories of minerals were extracted: tectosilicates, phyllosilicates, carbonates and sulphates. Detection of irradiation was reliable when based on the TL of tectosilicate minerals, i.e. quartz and feldspar. Suitable minerals were found in most seafood: only about five percent of all samples could not be successfully analysed because no minerals or only non-thermoluminescent clays or carbonates were found. False positive results were never obtained. A false negative decision results if analyses are based on hydrous clays or carbonates in the form of aragonite.     

Mode locking a 1550 nm semiconductor disk laser by using a GaInNAs saturable absorber

Passive mode locking of an optically pumped, InP-based, 1550 nm semiconductor disk laser by using a GaInNAs saturable absorber mirror is demonstrated. To reduce material heating and enable high-power operation, a 50 microm thick diamond heat spreader is bonded to the surface of the gain chip. The laser operates at a repetition frequency of 2.97 GHz and emits near-transform-limited 3.2 ps pulses with an average output power of 120 mW.     

Modulation and the linewidth enhancement factor of a diode-pumped Nd:YVO4 laser

A technique based on an FM/AM method is proposed for measuring the linewidth enhancement factor a of a diode-pumped Nd:YVO4 laser. A standard rate equation model is complemented with temperature effects to explain the observed behavior under pump modulation. The result alpha = 0.25 +/- 0.13 agrees with values deduced from recent optical injection experiments.     

Changes in Intestinal Permeability Ex Vivo and Immune Cell Activation by Three Commonly Used Emulsifiers

Food additives such as emulsifiers are used in increasing quantities in the food industry. The aim of this study was to compare three different emulsifiers (polysorbate 80 (P80), carboxymethyl cellulose (CMC), and β-lactoglobulin (β-lac) with regards to their effect on the stimulation of immune cells and intestinal permeability. The immune stimulatory effects were studied in the myeloid cell line MUTZ-3-cells, while the change in intestinal permeability was studied in the Caco-2 cell line and ex vivo in the Ussing chamber system using small intestinal fragments from rats. The tested concentrations of the emulsifiers ranged from 0.02% up to 1%, which are concentrations commonly used in the food industry. The results showed that P80 affected both the myeloid cells and the intestinal permeability more than CMC (p < 0.05) and β-lac (p < 0.05) at the highest concentration. CMC was found to neither affect the permeability in the intestine nor the MUTZ-3 cells, while β-lac changed the permeability in the total part of the small intestine in rats. These findings indicate that P80 might be more cytotoxic compared to the other two emulsifiers.