Spectral and spatial shaping of a laser-produced ion beam for radiation-biology experiments

International audience; The study of radiation biology on laser-based accelerators is most interesting due to the unique irradiation conditions they can produce, in terms of peak current and duration of the irradiation. In this paper we present the implementation of a beam transport system to transport and shape the proton beam generated by laser-target interaction for in vitro irradiation of biological samples. A set of four permanent magnet quadrupoles is used to transport and focus the beam, efficiently shaping the spectrum and providing a large and relatively uniform irradiation surface. Real time, absolutely calibrated, dosimetry is installed on the beam line, to enable shot-to-shot control of dose deposition in the irradiated volume. Preliminary results of cell sample irradiation are presented to validate the robustness of the full system

Caractérisation quantitative des acides gras insaturés et trans de la matière grasse du lait de brebis

[EN] Ewe's milk fat obtained from the milk of five different herds were studied to characterize main and minor fatty acids using a combination of gas chromatography and mass spectrometry. In order to assess monounsatured trans fatty acids content, fatty acid methyl esters (FAME) were fractionated by silver ion thin-layer chromatography prior to gas chromatography analysis. Trans fatty acids (TFA), including conjugated linoleic acid, represented 4.9% of the total FAME; most of them belonged to C18:l trańs isomers (2.9%) with a small range of variation (2.5-3.2%). The distribution profile of trans-C 18:1 molecules indicated that more than half were trans-11, whereas the proportion of potentially unhealthy compounds (trans-10 and trans-9 C18:1) was less than 10%. Mean trans-C16:1 content was 0.25% of total FAME. The sum of the different trans-C18:2 isomers (excluding conjugated linoleic acid) was 0.88% and C18:3 trans isomers represented 0.16%. [FR] Les acides gras mineurs et majeurs du lait de brebis provenant de cinq troupeaux différents ont été caractérisés par chromatographie gazeuse associée à la spectrométrie de masse. En vue de connaître le contenu en acides gras monoinsaturés trans, les esters méthyliques des acides gras ont été fractionnés en recourant à la chromatographie sur couche mince à l'ion argent suivie d'une analyse par chromatographie gazeuse. Les acides gras trans, incluant l'acide linoléique conjugué, représentaient 4,9 % du total des esters méthyliques des acides gras. La plupart d'entre eux appartenaient aux isomères trans du C18:1 (2,9 %) avec une variation faible entre les échantillons (2,5-3,2 %). Le profil de distribution des molécules C18:1 trans montraient que plus de la moitié étaient des trans-11, tandis que les proportions de trans-10 et trans-9, potentiellement nuisibles à la santé, étaient inférieures à 10 %. La teneur moyenne en C16 :1 trans était de l'ordre de 0,25 % du total des esters méthyliques des acides gras. Le total des différents isomères C18:2 trans (à l'exception de l'acide linoléique conjugué) et C18:3 représentait respectivement 0,88 % et 0,16 % du total.This work was supported by the Ministerio de Ciencia y Tecnología (Research Project AGL2002-0088-00887) and the Comunidad Autónoma de Madrid (Research Project 07G/0039/2003). http://dx.doi.org/10.1051/lait:2004017Peer Reviewe

TAG composition of Ewe's milk fat. Detection of foreign fats

The TAG composition of 45 samples of ewe's milk, collected throughout the year from five Spanish breeds, was analyzed according to their carbon number by using short capillary column GC. The TAG content had a bimodal distribution with maxima at C38 (12.8%) and C52 (8.4%). The TAG composition did not vary significantly with respect to the time of year of sampling but was affected by the breed. Multiple regression equations based on TAG content are proposed to detect foreign fats in ewe's milk fat. Analysis of known mixtures of lard, palm oil, and cow's milk fat with ewe's milk fat have experimentally confirmed the accuracy of the equations.This work was supported by the National Plan of Research (Project CAL01-013)

Le rôle de la protonthérapie dans les cancers de l’oesophage

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Identity of the major triacylglycerols in ovine milk fat

Ovine milk fat obtained from milk collected from five different flocks was studied to determine its triacylglycerol (TAG) composition using a combination of gas chromatography/mass spectrometry. One hundred and thirty-four molecular species of TAG were identified, but not all could be quantified because some peaks contained more than one species of TAG. Fifty-one per cent of the identified species were trisaturated TAGs, 31% as monounsaturated TAGs and 18% as polyunsaturated TAGs. In terms of chain length, 58 of the TAGs identified (43% of the total) contained short-chain (C4 and C6) fatty acids (FAs), 94 (70%) contained medium-chain FAs (C8-C14) and 112 (84%) were composed of long-chain FAs (C16-C18). One hundred and twenty nine chromatographic peaks were detected. The sum of the 35 peaks, each representing>1 mol% of the TAGs, was 75% of total TAGs. Five peaks, each with>3.5 mol% included trisaturated and monounsaturated TAGs; quantitatively, the largest of these peaks (4.5 mol% of the total TAGs) contained two esterified monounsaturated TAGs with C4: 4,16,18:1 or 4,18,16:1, with the former being present at the highest levels. Comparison of the experimental values of TAG composition in ovine milk with the theoretical values derived from the experimental FA content showed that the distribution of the FAs in the TAGs was not random. The TAGs containing a short-chain FA were synthesized preferentially to those TAGs containing three medium- or three long-chain FAs. Our results for ewes' milk were very similar to those for cows' and goats' milk despite the quantitative differences in the TAG profiles of the different species. © 2005 Elsevier Ltd. All rights reserved.Peer Reviewe

Composition of cholesterol and its precursors in ovine milk

[EN]: Identification and concentration of cholesterol and its precursors were investigated in ovine milk. In order to ensure a wide variety of milk composition, 45 samples were taken during the year from the bulk milk of five herds (ranging from 130 to 2500 adult ewes) corresponding to five breeds and located in different places in Spain. Gas chromatography/mass spectrometry analysis allowed the identification of small quantities of squalene, lathosterol, desmosterol, dihydrolanosterol and lanosterol. Neither campesterol nor $\beta$-sitosterol could be detected in the studied samples. The mean values (mg $\cdot$100 g -1 fat) were: cholesterol 288.44 $\pm$ 42.22; squalene 1.80 $\pm$ 0.99; lathosterol 1.81 $\pm$ 0.82; desmosterol 0.41 $\pm$ 0.30; dihydrolanosterol 4.15 $\pm$ 2.40 and lanosterol 6.86 $\pm$ 1.88. With the statistical model used, the cholesterol concentration in milk fat was shown to be influenced by an interaction between the factors time of year of sampling and breed, but the variations observed do not show a clear trend.[FR]: Composition du cholestérol et de ses précurseurs dans le lait de brebis. L'identification du cholestérol et ses précurseurs a été effectuée sur le lait de brebis et leur concentration mesurée. Afin de garantir une large variété de composition du lait, 45 échantillons ont été prélevés tout au long de l'année sur une quantité de lait de cinq troupeaux (allant de 130 à 2500 agnelles adultes) correspondant à cinq races et localisées dans différentes régions d'Espagne. L'analyse par chromatographie gaz/spectrométrie de masse a permis d'identifier une petite quantité de squalène, lathosterol, desmosterol, dihydrolanosterol et lanosterol. Ni le campesterol ni le $\beta$-sitosterol ne pouvaient être détectés dans les échantillons étudiés. Les valeurs moyennes (mg $\cdot$100 g -1 de matière grasse) ont été : cholestérol 288,44 $\pm$ 42,22; squalène 1,80 $\pm$ 0,99; lathosterol 1,81 $\pm$ 0,82; desmosterol 0,41 $\pm$ 0,30; dihydrolanosterol 4,15 $\pm$ 2,40 et lanosterol 6,86 $\pm$ 1,88. Les modèles statistiques utilisés ont permis l'observation d'une interaction entre l'effet période de l'année pour l'échantillonnage et la race sur la concentration du cholestérol dans la matière grasse du lait, mais les variations observées ne furent pas claires.This work was supported by the National Plan of Research (Project CAL01-013)

Towards scanning particle therapy at the Institut Curie – Centre de Protontherapie d’Orsay: detectors characterisation and development for relative dose metrology

Since 2010, at the Institut Curie – CPO, a 230 MeV IBA proton cyclotron delivers beam to two passive fixed treatment rooms and to one universal nozzle equipped gantry. In order to improve cancer treatment capabilities we are now involved in the transition towards scanning particle therapy. We describe here possible solutions for its relative dose metrology

A new layered potassium-based molybdenum-tungsten monophosphate: Synthesis, crystal structure, XPS and magnetic studies

A new compound, K-5[(Mo3.2W1.8)O-11](PO4)(3)[(P0.5Mo0.5)O-4], was synthesized via solid-state reaction and its crystal structure was determined by single-crystal X-ray diffraction. This compound crystallizes in the space group Pnma, with a = 9.0360(4) angstrom, b = 10.1603(4) angstrom, c = 26.1538(12) angstrom and V = 2401.14(18) angstrom(3). The structure consists of a corner-sharing MO6-TO4 (M = Mo, W; T = P, Mo) polyhedral connection arranged to form an ordered packing of similar to 14.9 angstrom-thick layers parallel to (001). The stacking of the layers forms trigonal, tetragonal and hexagonal channels. XPS study reveals the presence of W at the hexavalent state only, whereas Mo appears as a mixed-valent species (Mo6+, Mo5+ and Mo4+). Magnetic susceptibility reveals the occurrence of a relevant antiferromagnetic coupling and is consistent with the presence of reduced metal species as indicated by the XPS results

Experimental characterisation of a proton kernel model for pencil beam scanning techniques

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