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Anaerobic enrichment cultures with sediment from an intertidal strait as inoculum were established under denitrifying, sulfate-reducing, iron-reducing and methanogenic conditions to examine the biodegradation of mono-fluorophenol and mono-fluorobenzoate isomers. Both phenol and benzoate were utilized within 2-6 weeks under all electron-accepting conditions. However, no degradation of the fluorophenols was observed within 1 year under any of the anaerobic conditions tested. Under denitrifying conditions, 2-fluorobenzoate and 4-fluorobenzoate were depleted within 84 days and 28 days, respectively. No loss of 3-fluorobenzoate was observed. All three fluorobenzoate isomers were recalcitrant under sulfate-reducing, iron-reducing, and methanogenic conditions. The degradation of the fluorobenzoate isomers under denitrifying conditions was examined in more detail using soils and sediments from different geographic regions around the world. Stable enrichment cultures were obtained on 2-fluorobenzoate or 4-fluorobenzoate with inoculum from most sites. Fluoride was released stoichiometrically, and nitrate reduction corresponded to the values predicted for oxidation of fluorobenzoate to CO2 coupled to denitrification. The 2-fluorobenzoate-utilizing and 4-fluorobenzoate-utilizing cultures were specific for fluorobenzoates and did not utilize other halogenated (chloro-, bromo-, iodo-) benzoic acids. Two denitrifying strains were isolated that utilized 2-fluorobenzoate and 4-fluorobenzoate as growth substrates. Preliminary characterization indicated that the strains were closely related to Pseudomonas stutzeri.

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A mixture of pure and anhydrous glycol methacrylate and methyl methacrylate is used as an embedding medium for iliac bone biopsies. Infiltration is carried out at -20 C with the embedding medium and a cold inactivated catalyst-initiator system. Raising the temperature to 4 C initiates polymerization and limits the peak temperature of polymerization to 25 C. In this way, such thermolabile enzymes as osteoclastic acid phosphatase are preserved. After staining, sections are dehydrated in polyethylene glycol 400 30% in 2-propanol. This gives flat sections and improves staining properties.

RESUME:La polymCrisation de I'acttoxy-2 styrene, du parachloro acCtoxy-2 styrene, du paramb thy1 acCtoxy-2 styrene et du paranitro acetoxy-2 styrene a CtC obtenue avec des amorceurs radicalaires ou par voie thermique. Les polymtres obtenus possedent des masses moyennes en nombre atteignant 200000. L'Ctude du comportement thermique permet dVtablir que ces polymtres ne presentent pas de transition de phase, vitreuse ou cristalline. L'Ctude diklectrique de ces polymtres a CtC effectue: on releve des pertes de I'ordre de radian, pratiquement constantes dans un large domaine de t e m p h t u r e et de frCquence. Au-delA de 320°K on dCctle un mkanisme de relaxation de faible amplitude et la presence d'eau modilie sensiblement son comportement diklectrique. SUMMARY:Polymerization of acetoxy-2 styrene, parachloro acetoxy-2 styrene, paramethyl acctoxy-2 styrene and paranitro acetoxy-2 styrene was carried out by means of free radical initiators or by thermic reaction. The polymers therefrom showed molecular weights of about 200000. Studies on the thermal behaviour reveal that these polymers do not undergo any change of phase, either vitreous or crystalline. Dielectric experiments show losses of about 10 radian; the losses are practically constant within a large scale of temperature and frequency. Over 320°K one notices a relaxation process of small magnitude and the presence of water brings about a marked change in the way the polymer reacts to dielectric treatment. 45 J. P. Montheard, M. Camps, G. Seytre, J. Guillet et J. C. Dubois