2,3,7,8-四氯代二苯并二英(TCDD)和苯并芘(B[a]P)对原代培养鲫鱼肝细胞中卵黄蛋白原诱导的影响

通过测定原代培养鲫鱼(Carassius auratus)肝细胞中雌激素受体所介导的卵黄蛋白原(Vtg)生成以及芳香烃受体所介导的CYP1A1基因转录水平的变化, 建立了一种类雌激素体外实验模型. 实验结果表明, Vtg和Vtg mRNA���表达与己烯雌酚(DES)之间均有很好的剂量-效应关系, Vtg和Vtg mRNA���可作为指示类雌激素毒性的生物标志物. TCDD, B[a]P���显著抑制鱼肝细胞中DES诱导的Vtg和Vtg mRNA���表达, 呈明显的抗雌激素效应, 并同时激活了CYP1A1 基因的表达;

Immunofluorescence detection and localization of B[a]P and TCDD in earthworm tissues

An immunohistochemical method using antibodies against polycyclic aromatic hydrocarbons (PAHs) and dioxins was developed on frozen tissue sections of the earthworm Eisenia andrei exposed to environmentally relevant concentrations of benzo[a]pyrene (B[a]P) (0.1, 10, 50 ppm) and 2,3,7,8-tetrachlorodibenzo-para-dioxin (TCDD) (0.01, 0.1, 2 ppb) in spiked standard soils. The concentrations of B[a]P and TCDD in E. andrei exposed to the same conditions were also measured using analytical chemical procedures. The results demonstrated that tissues of worms exposed to even minimal amount of B[a]P and TCDD reacted positively and specifically to anti-PAHs and -dioxins antibody. Immunofluorescence revealed a much more intense staining for the gut compared to the body wall; moreover, positively immunoreactive amoeboid coelomocytes were also observed, i.e. cells in which we have previously demonstrated the occurrence of genotoxic damage. The double immunolabelling with antibodies against B[a]P/TCDD and the lysosomal enzyme cathepsin D demonstrated the lysosomal accumulation of the organic xenobiotic compounds, in particular in the cells of the chloragogenous tissue as well as in coelomocytes, involved into detoxification and protection of animals against toxic chemicals. The method described is timesaving, not expensive and easily applicable.

La enseñanza del francés como segunda lengua extranjera en B.U.P. C.O.U.

Se desarrolla el proyecto de una experiencia llevada a cabo en el instituto de Bachillerato Cardenal Herrera Oria, durante el curso 1977-1978. Esta experiencia se realiza con un grupo de alumnos de primero de BUP que optan por aprender francés como segundo idioma extranjero. Se exponen los objetivos, las etapas administrativas, la metodología y programación, actividades periescolares y evaluación y rendimiento.

Jornadas de estudio sobre la terminología lingüística en el B.U.P. (1. 1979. Cullera).

Se exponen los contenidos de las ponencias y comunicaciones que intervienen en las I Jornadas de Estudio sobre la terminología lingüística en el BUP, celebradas en Valencia en 1979, donde se reflexiona sobre la importancia de la cuestión terminológica para la enseñanza del castellano.

La enseñanza de la geografía y el estudio del entorno geográfico en el B.U.P.

Se plantea un nuevo enfoque de las clases de geografía del bachillerato, planteando un método de trabajo basado más en actividades y trabajos prácticos, que en la técnica memorística, por su gran valor formativo. Se proponen aquí dos experiencias de trabajos prácticos llevados a cabo por alumnos de segundo y tercero de BUP sobre un entorno rural y uno urbano, desarrollando la metodología, el plan de trabajo, las conclusiones y opiniones de los alumnos sobre dichas experiencias.

Aplicación de los Diagramas de Gantt a la programación del B.U.P. y C.0.U.

Las fases necesarias para elaborar un diagrama de Gant son: determinación de las actividades principales; estimación de la duración efectiva de las mismas; enunciación en el diagrama de las actividades principales y de su relación entre si; representación gráfica de su duración; su utilización sus limitaciones, las actividades que se presentan tienen que ser limitadas perfectamente sin excederse en detalles. Tienen a su favor que son fácilmente realizables por personas no especializadas y que su representación sinóptica e intuitiva es muy útil. En definitiva, podemos decir que es un método útil para las programaciones de los docentes y puede contribuir a la mejora de la enseñanza, ya que proporciona un método sencillo de resumir las progresiones efectuadas y anotar la marcha de las actividades es de fácil seguimiento y una clara visión de conjunto lo que contribuirá a una clara coordinación.

Confinement and surface effects in B and P doping of silicon nanowires

Several experimental groups have achieved effective n- and p-type doping of silicon nanowires (SiNWs). However, theoretical analyses on ultrathin SiNWs suggest that dopants tend to segregate to their surfaces, where they would combine with defects such as dangling bonds (DB), becoming electronically inactive. Using fully ab initio calculations, we show that the differences in formation energies among surface and core substitutional sites decrease rapidly as the diameters of the wires increase, indicating that the dopants will be uniformly distributed. Moreover, occurrence of the electronically inactive impurity/DB complex rapidly becomes less frequent for NWs of larger diameters. We also show that the high confinement in the ultrathin SiNWs causes the impurity levels to be deeper than in the silicon bulk, but our results indicate that for NWs of diameters larger than approximately 3 nm the impurity levels recover bulk characteristics. Finally, we show that different surfaces will lead to different dopant properties in the gap.

New measurement of the B-11(p,alpha(0))Be-8 bare-nucleus S(E) factor via the Trojan horse method

A new measurement of the B-11(p,alpha(0))Be-8 has been performed applying the Trojan horse method (THM) to the H-2(B-11,alpha Be-8(0))n quasi-free reaction induced at a laboratory energy of 27 MeV. The astrophysical S(E) factor has been extracted from similar to 600 keV down to zero energy by means of an improved data analysis technique and it has been compared with direct data available in the literature. The range investigated here overlaps with the energy region of the light element LiBeB stellar burning and with that of future aneutronic fusion power plants using the B-11+p fuel cycle. The new investigation described here confirms the preliminary results obtained in the recent TH works. The origin of the discrepancy between the direct estimate of the B-11(p,alpha(0))Be-8 S(E)-factor at zero energy and that from a previous THM investigation is quantitatively corroborated. The results obtained here support, within the experimental uncertainties, the low-energy S(E)-factor extrapolation and the value of the electron screening potential deduced from direct measurements.

Tissue-specific induction of EROD activity and CYP1A protein in Sparus aurata exposed to B(a)P and TCDD

The purpose of this study was to compare xenobiotic CYP1A induction in liver, gills, and excretory kidney of gilthead seabream, Sparus aurata. Fishes were exposed via water for 20 days to different concentrations of benzo(a)pyrene (B(a)P) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). CYP1A was measured at the enzyme activity level as 7-ethoxyresorufin-O-deethylase (EROD) activity, and at the protein level by means of ELISA. The liver displayed the highest absolute levels of EROD activity, both under non-exposed and exposed conditions. Organ- or inducer-related differences in the time course of CYP1A induction were moderate; however, the magnitude of the induction response varied between the organs and between B(a)P and TCDD. In the case of TCDD, liver, and kidney yielded a comparable induction response, whereas in the case of B(a)P, the kidney showed a substantially higher maximum induction factor than the liver. In the gills, the two xenobiotics resulted in similar maximum induction factors. In B(a)P-exposed seabream, EROD activities and CYP1A protein levels showed a good correlation in all three organs, whereas with TCDD as inducer the correlation was poor, what was mainly due to a decrease of EROD activities at the higher concentrations of TCDD, while CYP1A protein levels showed no concomitant decline. Overall, the study revealed both similarities and differences in the time-, concentration-, and inducer-dependent CYP1A responses of the three target organs, liver, kidney, and gills. Although, the findings of this study principally confirm the notion of the liver as the major metabolic organ in fish, they also provide evidence for substantial metabolic potential in gills and particularly in the kidney.