ABSTRACT This study aimed to identify alterations in gills and hepatopancreas of the crab Ucides cordatus as indicative of environmental contamination in mangrove areas subject to chemical effluents from port activities in Maranhão, Brazil. Samples of gills and hepatopancreas were removed from each animal and fixed in Davidson's solution until the procedure of histological technique. The biometric data (means and standard deviations) of the specimens collected in the study areas indicated that the crabs in the reference area are significantly (P < 0.05) higher and heavier than the crabs collected in the potentially impacted area (port area). Gill alterations (rupture of pilaster cells, dilation of the marginal channel, cuticle rupture and necrosis) and hepatopancreas alterations (abnormal lumen, vacuolized B cells, pycnotic nuclei and necrosis) were significantly (P < 0.05) more frequent in crabs collected in the port area than crabs collected in the reference area. These data indicate that the health of crabs is compromised due to the pollutants present in the mangroves that surround the port area in São Marcos' Bay.

The present paper describes the synthesis of crystalline zirconium hydrogen phosphate by direct precipitation and its intercalation with pyridine and n-butylamine. The simple experiment was tested in the undergraduate inorganic chemistry laboratory course for chemistry students at IQ-UNICAMP using inexpensive reagents. The materials were characterized by powder X-ray diffraction and infrared analyses in order to obtain detailed information of the solid structure changes as a result of the intercalation process. Pyridine and n-butylamine are focused in this work as clear and elucidative examples leading to acid-base interactive processes that result in the well-formed infinite sequence of inorganic lamellar structures.

A simple experiment for the preparation of transparent conducting glass electrodes by deposition of pure and fluorine doped SnO2 films is described. This procedure was tested in the undergraduate inorganic course at IQ-UNICAMP. The success in achieving a conducting layer was easily checked using the standard probes of a volt-ohm meter. The optical transmittance and thickness were studied by UV-vis spectrophotometry. To discuss the experimental results we place significant emphasis on molecular orbital and energy band model theories. The undergraduate students can also discuss the concepts related to the electronic properties of solids and to interesting new materials, such as transparent conducting films, which are the subject of significant current research and technological applications.