Selective synthesis of turbostratic polyhedral carbon nano-onions by arc discharge in water

Carbon nano-onions (CNOs), in their spherical or polyhedral forms, represent an important class of nanomaterials, due to their peculiar physical and electrochemical properties. Among the different methods of production, arc discharge between graphite electrodes sustained by deionized water is one of the most promising to obtain good quality CNOs in gram quantities. We applied the method with the aim to optimize the production of CNOs, using an innovative experimental arrangement. The discharges generate dispersed nanomaterials and a black hard cathodic deposit, which were studied by transmission electron microscopy-high-resolution TEM, scanning electron microscopy, Raman, thermogravimetric analysis and energy-dispersive x-ray spectroscopy. A simple mechanical grinding of the deposits permitted us to obtain turbostratic polyhedral CNOs that exhibited higher stability towards burning in air, compared to CNOs found in water. We propose a mechanism for the formation of the CNOs present in the deposit, in which the crystallization is driven by a strong temperature gradient existing close to the cathode surface at the beginning of the process, and subsequently close to the deposit surface whenever it is growing.

Compliance with pharmacologic prophylaxis and therapy in bronchial asthma

Between January 1 and December 31, 1988, 288 children [185 boys and 103 girls, mean age 8.75 +/- 4.98 years (range 2.50 to 16.83)], followed at the Outpatient Clinic for Lung Diseases of the University of Milan 5th Pediatric Department, were interviewed blindly in order to assess their compliance with pharmacologic therapy. All children were suffering from episodic, frequent, or chronic asthma requiring therapy as needed and preventive drugs for at least 30 days. Prophylaxis (including cromolyn, beclomethasone, theophylline retard, ketotifen, oxatomide, albuterol, and prednisone, alone or in combinations) and therapy in case of symptoms (albuterol, with or without theophylline prompt or beclomethasone) were prescribed. A study questionnaire was completed 30 to 45 days after the prescription with no advance warning by a physician unaware of the prophylactic and therapeutic prescriptions. Out of the 288 patients, 31 (10.8%) failed to return for the second visit. Understanding of prophylaxis was full in 61.1% of cases, partial in 23.3% and nil in 4.9%. Therapy as needed was fully remembered by 77.1% of parents, partially by 9.4% and totally forgotten by 2.8%. Compliance with single-drug prophylaxis was full in 60.1% of cases, partial in 22.2% and nil in 6.4%. Statistical analysis showed compliance was significantly better for ketotifen than for disodium cromoglycate (chi squared 9.85, P < .02), for ketotifen than for theophylline (chi squared 9.98, P < .02), and for beclomethasone than for theophylline (chi squared 8.77, P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)