Effect of Some Additives on the Specific Surface of Alumina Obtained from Aluminum-Ammonium Alum

The effect of Al(NO₃)₃·9H₂O, AlCl₃·6H₂O, Al(CH₃COO)₃, and NH₄F on the specific surface of Al₂O₃ obtained from aluminum-ammonium alum by calcining was studied. It was found that the use of these additives makes it possible to obtain Al₂O₃ with specific surface varying from 1 to 135 m²/g after thermal treatment in the interval from 1273 to 1423 K. The changes in the morphology and structure of powederd Al₂O₃ obtained from alum containing these additives were studied by electron microscope observations.     

Video-assisted thoracic surgery in patients with spontaneous pneumothorax

Following the development of video-assisted technologies and the principle of minimally-invasive surgery thoracoscopy has finally established itself as an integral part of the surgeon's armamentarium in the treatment of spontaneous pneumothorax. This procedure was performed on 18 patients at the Department of Cardio-Thoracic Surgery of the Medical University in Vienna from October 1995 to April 1996 and on 5 patients at the Department of Thoraco-Abdominal Surgery of the Medical University in Plovdiv from October 1996 to January 1997, all of which had been diagnosed as having complicated spontaneous pneumothorax. The main indications were: recurrent spontaneous pneumothorax or persistent pneumothorax following a five-day unsuccessful drainage of the pleural cavity. All our patients underwent partial parietal pleurectomy down to the level of the third intercostal space. Apical blebs were found in 14 patients and atypical wedge resection was performed. The authors used three trocars 5-12 mm in diameter. The thoracoscope was inserted in the fifth intercostal space in the midaxillary line. The other two operative trocars were inserted in the anterior and posterior axillary lines, respectively. The mean postoperative stay was 6 days. Our results support the view that video-assisted thoracic surgery is technically feasible and safe, associated with decreased perioperative pain and opiate requirements, shorter hospital stay, excellent cosmetic results, low recurrence rate, early return to routine activity and minimal morbidity and is therefore superior to conventional thoracotomy.