Solute hydrogen and hydride phase implications on the plasticity of zirconium and titanium alloys: a review and some recent advances.

In this contribution, we propose a review of the possible implications of hydrogen on mechanical behaviour of Zr and Ti alloys with emphasis on the mechanisms of plasticity and strain hardening. Recent advances on the impact of oxygen and hydrogen on the activation volume show that oxygen content hinders creep but hydrogen partially screens this effect. Both aspects are discussed in terms of a locking-unlocking model of the screw dislocation mobility in prismatic slip. Additionally, possible extension of this behaviour is suggested for the [Formula: see text] pyramidal slip. The low hydrogen solubility in both Zr and Ti leads in many cases to hydride precipitation. The nature of these phases depends on the hydrogen content and can show crystallographic orientation relationships with the hexagonal compact structure of the alloys. Some advances on the thermal stability of these phases are illustrated and discussed in relation with the deepening of the misfit dislocations. Under tensile loading, we showed that hydrides enhance the hardening process in relation with internal stress due to strain incompatibilities between the Zr and Ti matrix and hydride phases. Different plastic yielding processes of hydrides were identified, which progressively reduce these strain incompatibilities.This article is part of the themed issue 'The challenges of hydrogen and metals'.

Characterisation of CIME, an experimental chamber for simulating interactions between materials of the cultural heritage and the environment.

An approach consisting in combining in situ and laboratory experiments is often favoured for investigating the mechanisms involved in the weathering of the materials of the cultural heritage. However, the realistic simulation in the laboratory of the environmental conditions ruling the interactions of atmospheric compounds with materials is a very complex task. The aim of this work is to characterise CIME, a new chamber specially built to simulate the interactions between materials of the cultural heritage and the environment. The originality of this instrument is that beside the usual climatic parameters (temperature, relative humidity, solar radiation) and gaseous pollutants, it also allows the controlled injection of different types of particulate matter such as terrigenous, marine and anthropogenic. Therefore, varied realistic atmospheric environments (marine or urban) can be easily simulated within CIME. In addition to the technical description of CIME, this paper shows the first results obtained by the impact of gaseous pollutants on non-durable glass, bronze and limestone. The first experiments for the deposition of different particles (calcite, clays, soot and halite) are also presented.

[Immediate reactions to local anesthetics: diagnostic and therapeutic procedures]. / Réactions d'allure immédiate aux anesthésiques locaux: démarche diagnostique et thérapeutique.

BACKGROUND: Despite the widespread use of local anesthetics and frequently reported adverse reactions, true IgE-mediated allergy to local anesthetics is extremely rare. We report on 80 patients seen in our department for adverse reactions to local anesthetics, and we propose a clinical strategy to confirm or rule out immediate allergy to local anesthetics. PATIENTS AND METHODS: We retrospectively analyzed the medical files of all patients referred to our department by their doctor or dentist for suspected immediate allergic reaction to local anesthetics between September 2001 and May 2004. These patients underwent skin tests (prick test and intradermal tests) exploring immediate allergy. RESULTS: Eighty cases were tested in our department during this period. The most common symptoms were facial edema or dizziness following injection of an anesthetic occurring between a few seconds and more than 48 hours after administration. The causative local anesthetics were of the amide group in 91% of cases and of the ester group in 9% of cases. Seventy-nine patients had negative skin tests, allowing us to eliminate the diagnosis of immediate allergy, and the anesthetic could be reinjected with good tolerability. One patient presented with positive skin tests to lidocaine and cross reactivity to mepivacaine. COMMENTS: Adverse reactions to local anesthetics are common and are mostly of pharmacological or toxic origin. However, allergic accidents with local anesthetics are rare and are mostly of type IV involving specific T cells. Immediate allergy to local anesthetics remains extremely rare with less than 10 authentic documented cases being published to date. Skin tests offer a reliable method for exploring immediate allergy in our experience and we propose a diagnostic strategy to confirm or rule out immediate allergy to local anesthetics.

[Acquired zinc deficiency in a breast-fed premature infant]. / Déficit acquis en zinc chez un prématuré nourri au sein.

UNLABELLED: Symptomatic zinc deficiency can occur in exclusively breast-fed infants. We report a case in a preterm infant. CASE REPORT: A 3-months-old exclusively breast-fed premature infant presented with peri-orificial and acral eczematoid lesions. Laboratory investigations revealed lowered zinc levels in the infant's serum and in her mother's milk. A rapid healing occurred after oral zinc supplementation. DISCUSSION: Zinc deficiency in breast-fed infants is a rare disease caused by a low level of zinc in mother's milk. The clinical features resemble those of acrodermatitis enteropathica. Oral zinc supplementation is required until weaning.

New approach for accurate simulation of human pharmacokinetics in an in vitro pharmacodynamic model: application to ciprofloxacin.

An in vitro pharmacodynamic model using a disposable dialyser unit and computer-controlled devices was developed. Feedback control of peristaltic pump flow rates is used to maintain constant flow rates, thus avoiding the problem of the modification of the physical properties of the tubing that generally occurs. Fast equilibrium is obtained with capillaries, which allows simulation of the same kinetic profile in the central and the peripheral compartments. Thus, more accurate simulation of plasma, extracapillary fluid or whole tissue kinetics can be performed. Our model was validated by simulation of a 30 min infusion of a 200 mg dose, and of an oral administration of a 500 mg dose of ciprofloxacin.

[Bioavailability of cadmium: effect of vitamin C and phytase in broiler chickens]. / Zur Bioverfügbarkeit von Kadmium: Einfluss von Vitamin C und Phytase beim Hühnerküken.

Though the application of the toxic heavy metal cadmium is reduced, its concentration in soil and in feed still increases. Especially smoking habits and unbalanced diets cause cadmium intake in humans beyond the limits suggested by WHO. One possibility to reduce cadmium burden is to influence the bioavailability of cadmium in the feed by certain vitamins, trace elements and other feed components and thus to lower its content in food from animal origin. In the present study the influence of vitamin C and phytase on the bioavailability of cadmium was investigated in broiler chicken. It was shown that 1 g vitamin C per kg of feed lowered cadmium accumulation in kidney and in liver by up to 40%. Addition of phytase, a new feeding enzyme, licensed in 1992 in Germany for improving phosphate utilization from phytate, lowered cadmium accumulation by up to 60%. Therefore the addition of these two components to the feed lowers the cadmium burden in food from animal origin and thus increases its quality.

Single column ion chromatographic determination of inorganic acids in workroom places.

Single Column Ion Chromatography (SCIC) combines low capacity-columns, low conductivity eluents and a detector with considerable electronic supression capability and enables quantitation of ions at the ppm level without the need of a suppressor column associated with other forms of Ion Chromatography. Vapors and aerosols of inorganic acids are collected on filter and silica gel tubes and analyzed directly by SCIC. A conventional liquid chromatograph with a low capacity column and a conductimetric detector is used to analyze aerosols of Cl-, Br-, NO-3 and SO=4 with good results.

Cáncer de colón y recto. Revisión estadística / Colonic and rectal cancer

Se revisan las historias clínicas de 70 pacientes con cáncer de colon y recto ingresados en el hospital docente clinicoquirúrgico "10 de Octubre" durante el período comprendido entre octubre de 1969 hasta septiembre de 1971. Se señalan los síntomas, tratamiento y evolución pre y posoperatoria de 46 de ellos, ya que sólo estos fueron útiles para realizar este estudio. Se destaca que el tratamiento precoz salvaría al 75 porciento de los casos afectados (AU)