Ultraviolet Photoluminescence from Gd-implanted AlN Epilayers

Deep ultraviolet emission from gadolinium (Gd)-implanted AlN thin films has been observed using photoluminescence (PL) spectroscopy. The AlN epilayers were ion implanted with Gd to a total dose of similar to 6x10(14) cm(-2). Using the output at 197 nm from a quadrupled Ti:sapphire laser, narrow PL emission was observed at 318 nm, characteristic of the trivalent Gd ion. A broader emission band, also centered at 318 nm, was measured with excitation at 263 nm. The PL emission intensity decreased by less than a factor of 3 over the sample temperature range of 10-300 K and decay transients were of the order of nanoseconds.</p

Comparison between the Percutwist and the Ciaglia percutaneous tracheotomy techniques.

A prospective study was designed to compare two single-dilator percutaneous tracheotomy techniques, the Ciaglia BlueRhino and the Percutwist technique. One hundred and ninety adult patients were included, 166 with the BlueRhino, a conical shaped, flexible rubber dilator, and 24 with the Percutwist, a screw like dilating device. The procedure was performed under fiberscopy in the intensive care unit (ICU). Age, body mass index (BMI), indication for tracheotomy, surgical landmarks, duration of the procedure and surgical complications were recorded. Median age and indications were similar for the two groups. Dilation was successful in all patients. The mean time for surgery was shorter with the Ciaglia technique: 8 +/- 3 versus 12 +/- 5 min with the Percutwist technique (P = 0.004). There was no significant difference related to weight, BMI, duration of tracheotomy and complications between both groups. One posterior tracheal wall puncture was observed with the Ciaglia technique and four with the Percutwist technique. No serious complications were noted with either technique. The Percutwist technique represents an alternative to the more established Ciaglia BlueRhino technique. The Ciaglia technique is a safe and more rapid procedure for bedside tracheotomy