Narrow Results

A novel and uncomplicated method for preparing nanocrystalline zinc oxide by precipitation in a basic aqueous solution with the addition of an oxidation agent and in the presence of flowing gas is presented. Firstly, the value of pH of the starting solution containing the zinc salts is adjusted to a value of 5–5.5. Then, zinc oxide is precipitated by adding NH₄OH and bubbling flowing air. Finally, the precipitated materials are washed with a basic solution (0.01 M NaOH). The X-ray diffraction patterns show nanocrystalline single-phase ZnO with a grain size of 12–14 nm (Scherrer method). No further thermal treatment of the prepared material is required. The surface of the prepared material can be successfully modified. This new route is reproducible and can be used on industrial level.

Chemical injury to the eye is still an important cause of blindness and serious complications. Gaseous ammonia combines with tissue water to form ammonium hydroxide (NH₄OH). This exothermic reaction results in both heat and chemical burns. Although, over the years, the different biological effects of anhydrous ammonia are well known, its ocular effects are less clearly documented. This study reports the corneal structural alterations that may be induced as a result of ammonia exposure (gas or liquid) that was studied by Fourier transform infrared spectroscopy. The resulted IR spectra were analyzed using the band enhancement procedure. The obtained data clearly indicate that there are different structural and conformational changes (includes lipids and proteins) as the method of exposure to the ammonia differ, and due to the increased ammonia occupational exposure, there is an insistent need for the development of ophthalmic medications.