Browsing by Author "Palma, L"

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    Anode-support system for the direct electrorefining of cement copper .3. Pretreatment and process conditions to refine industrial cement
    (1997) Figueroa, M; Gana, R; Kattan, L; Mendez, S; Palma, L
    This paper describes the final part of a study on the utilization of a special anode-support system for the electrorefining of industrial cement copper produced by small mines. This type of cement is obtained from the leaching solutions of copper oxide minerals by precipitation with iron scrap. The cement is highly contaminated with iron, different metallic and non-metallic compounds and chloride. Therefore it is necessary to purify the cement copper before the electrorefining process. A two-stage method of purification is proposed, washing with water (pH4) to eliminate chloride and soluble species and magnetic removal of the metallic iron. A circular cell provided with an annular AISI-316 stainless steel mesh supporting the mass of cement copper was utilized. A vertical rotary cylinder of AISI-316 stainless steel was used as the cathode. As operating conditions, a solution of CuSO4 . 5H(2)O: 150 g dm(-3) and H2SO4: 50 g dm(-3), j(c): 5.0 A dm(-2), T: 40 degrees C, u: 60 rpm, were used. A cement copper of 85% purity was utilized. Under these recommended operating conditions it is possible to obtain copper sheets of good quality, meeting the ASTM B-11591 specification for commercial cathodes.
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    Incidence of BRCA1 and BRCA2 mutations in 54 Chilean families with breast/ovarian cancer, genotype-phenotype correlations
    (2006) Gallardo, M; Silva, A; Rubio, L; Alvarez, C; Torrealba, C; Salinas, M; Tapia, T; Faundez, P; Palma, L; Riccio, M; Paredes, H; Rodriguez, M; Cruz, A; Rousseau, C; King, M; Camus, M; Alvarez, M; Carvallo, P
    Our aim was to analyze the incidence of mutations in BRCA1 and BRCA2 genes in 54 families with breast/ovarian cancer. Families were selected from three Institutions following the standard criteria for hereditary breast/ovarian cancer. PCR amplification of all exons was performed, followed by SSCP, heteroduplex, PTT and sequencing analysis. We identified eight truncation mutations, three in the BRCA1 gene and five in the BRCA2 gene. Three of these mutations have not been reported previously by other groups: 308insA in one family, 3936 C > T in two families, for BRCA1, and 4970insTG in one family for BRCA2. In addition two families having Ashkenazi Jewish ancestors present the well known mutations 185delAG and 6174delT. Interestingly, 5 out of 11 families have mutations recurrent in Spanish families. Among the 54 families selected, seven have breast and ovary cancer cases, and only two presented a mutation in BRCA1 or BRCA2 genes. Other cancers as prostate and stomach are frequent among relatives carrying the mutation. Five cases of very early onset (< 31 years old) breast cancer were detected. The frequencies of BRCA1 (0.074) and BRCA2 (0.13) mutations in our families is low but similar to the incidence found in other populations, like in Spain. Since is widely known that risk factors that modulate the development of breast cancer such as lifestyle risk factors, geographic location, country of origin and socioeconomic status, besides a familial history of breast cancer our findings suggest that the history of colonization and immigrations is very relevant when studying hereditary factors associated to breast cancer.