Thermal inactivation kinetics of alkaline phosphatase in equine milk

Alkaline phosphatase (ALP) is widely used as an indicator of proper pasteurization in bovine milk. Due to interest in the use of equine ALP as a time/temperature integrator (TTI) for evaluation of the efficacy of thermal processing of equine milk, its inactivation kinetics were evaluated in whole and skimmed equine milk. Experimentally determined decimal reduction times showed that equine ALP is more readily inactivated in equine milk than its bovine counterpart. Thus, considering the required 6 D reduction of pathogens and the rather low enzyme level present in equine milk, equine ALP will not be suitable as indicator for correct pasteurization of equine milk under the conditions currently used in the reference method for the determination of ALP in milk-based products.     

Cryogenic Ge Detectors for Dark Matter Search: Surface Event Rejection with Ionization Signals

A new design of an ionization-heat germanium detector for dark matter search is presented, based on the use of interleaved electrodes for charge collection. This device allows active rejection of surface events by performing the appropriate cuts in the charge measurement data. Test experiments were performed with a prototype device, fitted with annular collection electrodes and with a neutron transmutation-doped Ge thermometer. Calibration runs with gamma and neutron sources demonstrate the remarkable possibilities offered by this type of detector in terms of surface event discrimination.      

Critères généraux de conception des réseaux de diodes lasers à rubans couplés par champs évanescents

The aim of this article is to define the general criteria for design of phase-locked diode laser arrays. A general method for designing these devices is presented using the effective index method and the coupled mode theory. The confinement required for the individual diodes is defined, and the allowed structure geometries are determined.     

Study of oxidation after monoacrylate grafting on polyethylene

BACKGROUND: The surface properties of high‐density polyethylene and linear low‐density polyethylene were modified by grafting urethane monoacrylate monomer under UV irradiation. This graft polymerization was carried out on native substrates and on substrates pre‐treated by wet oxidation, for different oxidation times. RESULTS: As the urethane monacrylate layer is crosslinked, its grafting efficiency was checked by dissolving the polyethylene substrates in hot toluene. Grafting was evidenced by Fourier transform infrared spectroscopy of the obtained residues, which showed that both the characteristic urethane acrylate (3350 cm^?1) and polyethylene (2920, 730 and 720 cm^?1) bands were observable for any polyethylene oxidation time. For an oxidation time longer than 10 hours, acrylate grafting was homogeneous and the grafted surface was smooth with a roughness of less than 10 nm. In addition, X‐ray photoelectron spectroscopy analysis of the residues revealed that O/C had an average value of 0.19, which is lower than the value corresponding to pure acrylate (0.42), whereas N/C had an average value of 0.068, also lower than that of pure acrylate (0.09), thus confirming the grafting. CONCLUSION: A urethane monoacrylate layer was grafted on native and oxidized polyethylene films. For highly oxidized films, the grafted surfaces are smooth and homogeneous. Copyright © 2008 Society of Chemical Industry     

Surface Event Rejection of the EDELWEISS Cryogenic Germanium Detectors Based on NbSi Thin Film Sensors

Near-surface-events are a major limitation to the performance of cryogenic massive germanium heat and ionisation detectors for dark matter search, due to their incomplete charge collection. We present here a powerful method of surface event identification based on the transient heat signal of a Ge bolometer, equipped with two NbSi high impedance thin film sensors. Calibration runs using electrons and low energy gamma particles from a ¹⁰⁹Cd source show highly effective surface event rejection down to the heat threshold energy. Neutron and gamma source calibrations were realised to get information on the fiducial volume of the Ge absorber. First results from low background data taking are discussed.     

MA‐NOTMP: A Triazacyclononane Trimethylphosphinate Based Bifunctional Chelator for Gallium Radiolabelling of Biomolecules

In the past few years, gallium‐68 has demonstrated significant potential as a radioisotope for positron emission tomography (PET), and the optimization of chelators for gallium coordination is a major goal in the development of radiopharmaceuticals. Methylaminotriazacyclononane trimethylphosphinate (MA‐NOTMP), a new C‐functionalized triazacyclononane derivative with phosphinate pendant arms, presents excellent coordination properties for ⁶⁸Ga (low ligand concentration, labelling at low pH even at room temperature). A “ready‐to‐be‐grafted” bifunctional chelating agent (p‐NCS‐Bz‐MA‐NOTMP) was prepared to allow ⁶⁸Ga labelling of sensitive biological vectors. Conjugation to a bombesin_(7–14) derivative was performed, and preliminary in vitro experiments demonstrated the potential of MA‐NOTMP in the development of radiopharmaceuticals. This new chelator is therefore of major interest for labelling sensitive biomolecules, and further in vivo experiments will soon be performed.     

Assessing the Antimicrobial Activity of Polyisoprene Based Surfaces

There has been an intense research effort in the last decades in the field of biofouling prevention as it concerns many aspects of everyday life and causes problems to devices, the environment, and human health. Many different antifouling and antimicrobial materials have been developed to struggle against bacteria and other micro- and macro-organism attachment to different surfaces. However the “miracle solution” has still to be found. The research presented here concerns the synthesis of bio-based polymeric materials and the biological tests that showed their antifouling and, at the same time, antibacterial activity. The raw material used for the coating synthesis was natural rubber. The polyisoprene chains were fragmented to obtain oligomers, which had reactive chemical groups at their chain ends, therefore they could be modified to insert polymerizable and biocidal groups. Films were obtained by radical photopolymerization of the natural rubber derived oligomers and their structure was altered, in order to understand the mechanism of attachment inhibition and to increase the efficiency of the anti-biofouling action. The adhesion of three species of pathogenic bacteria and six strains of marine bacteria was studied. The coatings were able to inhibit bacterial attachment by contact, as it was verified that no detectable leaching of toxic molecules occurred.