Atomic-resolution electrochemistry with the atomic force microscope: copper deposition on gold

The atomic force microscope (AFM) was used to image an electrode surface at atomic resolution while the electrode was under potential control in a fluid electrolyte. A new level of subtlety was observed for each step of a complete electrochemical cycle that started with an Au(111) surface onto which bulk Cu was electrodeposited. The Cu was stripped down to an underpotential-deposited monolayer and finally returned to a bare Au(111) surface. The images revealed that the underpotential-deposited monolayer has different structures in different electrolytes. Specifically, for a perchloric acid electrolyte the Cu atoms are in a close-packed lattice with a spacing of 0.29 +/- 0.02 nanometer (nm). For a sulfate electrolyte they are in a more open lattice with a spacing of 0.49 +/- 0.02 nm. As the deposited Cu layer grew thicker, the Cu atoms converged to a (111)-oriented layer with a lattice spacing of 0.26 +/- 0.02 nm for both electrolytes. A terrace pattern was observed during dissolution of bulk Cu. Images were obtained of an atomically resolved Cu monolayer in one region and an atomically resolved Au substrate in another in which a 30 degrees rotation of the Cu monolayer lattice from the Au lattice is clearly visible.     

Adrenal adenoma in a cross-bred terrier

An adrenal tumour was diagnosed in a 12-year-old female cross-bred terrier. The dog was presented to the veterinary clinic because she had been gaining weight and had started urinating in the owners' house. Clinical findings included obesity, abdominal enlargement, thinning of the hair coat, seborrhoea sicca, and polydipsia and polyuria. The diagnosis was made by clinical pathology, endocrine function tests and abdominal radiography. Surgical removal of the neoplastic right adrenal gland resulted in resolution of the clinical signs, including regrowth of the hair coat.