A new method forin-situ measurement of electrical resistivity of reinforced concrete

A new method is described for thein-situ measurement of electrical resistivity of concrete structures. The method is based on the early work of J. Newman who calculated the electrolyte resistivity between a disk and a counter electrode located at infinity. This method has the advantage compared with Wenner's of using a single small electrode for the measurements. In this paper, results are presented comparing this method with Wenner's and with results carried out using a conductivity cell in electrolytes. Finally, values of resistivity are compared to corrosion intensity, and a threshold for active corrosion is suggested.

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Résumé On décrit une nouvelle méthode de mesure de la résistivité électrique du béton dont la technique est basée sur un travail ancien de J. Newman qui avait calculé la résistivité entre un disque et une électrode auxiliaire placée à l'infini. Comparée à la méthode de Wenner, cette méthode présente l'avantage de n'utiliser, pour les mesures, qu'une petite électrode. Dans cet article, on présente les résultats de la comparaison établie avec la méthode de Wenner et avec les résultats obtenus avec une cellule de conductivité placée dans les électrolytes. Enfin, on compare les valeurs de la résistivité du béton avec celles de l'intensité de la corrosion et on suggère un seuil de corrosion active.

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Editorial note Camen Andrade and Maria-Cruz Alonso are working at the Instituto Eduardo de Torroja which is a RILEM Titular Member. Dr. Andrade, who was the 1986 RILEM Medallist, have had all these years great responsibilities within RILEM. Chairlady of the Advisory Technical Committee until 1993, she is now a member of the Coordinating Committee. She is active in 116-PCD Technical Committee on Permeability of Concrete as a Criterion of its Durability and has been appointed chairdlady of 154-EMC Technical Committee on Electrochemical Techniques for Measuring Metallic Corrosion. Carmen Andrade has been appointed RILEM Fellow in 1995.     

Local synthesis of immunoglobulins in neuropathies

It is essential to know how the immune system acts in different neurological diseases, some of them non very well known or of unknown etiology at all. It was applied Reiber and Felgenhauer's formula in 56 patients with different diseases. IgA, IgM, IgG and albumin were quantified in sera and cerebrospinal fluid by simple immunodiffusion. It was observed more frequent IgG local synthesis and IgA in this sample.     

Prevalence of Staphylococcus aureus among food handlers from a metropolitan university in Chile

BACKGROUND: An important agent of food intoxication is Staphylococcus aureus, that is able to produce enterotoxins. AIM: To detect Staphylococcus aureus contamination in cafeteria food handlers of a Chilean University. SUBJECTS AND METHODS: Nose, throat, hands and nail samples from 87 food handlers were obtained for microbiological examination. RESULTS: Fifty seven subjects (65.5%) were carriers of Staphylococcus aureus. Enterotoxigenic Staphylococcus aureus was found in 36 subjects (41%). The most frequently found enterotoxin was type B (18 samples) followed by type D (12 samples). Men bad a higher frequency of contamination than women (83 and 57% of positive samples respectively). CONCLUSIONS: The frequency of Staphylococcus aureus contamination among food handlers is high and should prompt personal and environmental hygienic measures.     

Nucleoli and argyrophil nucleolus organizer regions (AgNORs) of cells of the megakaryocytic line in the rat

The main maturation stages of Norway rat megakaryocytic series, megakaryoblasts and mature megakaryocytes, stained by silver for demonstration of argyrophil nucleolus organizer regions (AgNORs) were investigated to provide basic information on the number of nucleoli and interphasic AgNORs in these cells. The results showed that megakaryoblasts as well as mature megakaryocytes possess numerous nucleoli; their number and also the number of AgNORs is significantly higher in less mature than in more mature cells. The number of AgNORs in megakaryocytes of the Norway rat and man are virtually the same, although the numbers of nucleolar organizers per haploid chromosome set differ markedly. This fact leads to the conclusion that the number of interphasic AgNORs depends on the function and metabolic state of the cell rather than on the number of nucleolar organizers.     

Spot welding of metal laminated composites

Composite materials of steel sheets joined by interlayers of zinc or lead- tin, show very good impact and corrosion resistance properties. Resistance spot-weld characteristics of these composite materials made of steel sheets and non-ferrous metals have been tested. Spot welds of composites with both zinc and lead- tin interlayers present good behaviour in peeling tests. Shear tests of the welds also show very high strength, probably as a consequence of simultaneous brazing because of the alloyed layer of non-ferrous material around the weld spot. This good welding behaviour enhances the possibilities of application of this composite.     

Cloning and sequencing of a tpr-met oncogene cDNA isolated from MNNG-transformed human XP fibroblasts

A rearranged tpr-met oncogene was identified in a MNNG-transformed human Xeroderma pigmentosum (XP) cell line (ASKMN). A 2016 bp cDNA was cloned and sequenced, disclosing an ORF with a coding capacity for a 523 aa protein. The sequence of this tpr-met cDNA was very similar to that previously reported in another human MNNG-transformed cell line (MNNG-HOS).