Tracheostomy tubes are used to administer positive-pressure ventilation, to provide a patent airway, to provide protection from aspiration, and to provide access to the lower respiratory tract for airway clearance. They are available in a variety of sizes and styles, from several manufacturers. The dimensions of tracheostomy tubes are given by their inner diameter, outer diameter, length, and c...

The special problems of preparing suspensions of cell fractions such as mitochondria for electron microscopy are largely eliminated once the fixed organclles are gathered into a cohesive pellet. Thesc pellets may then be handled in the manner conventional for blocks of tissue (1, 2). The use of very small samples (e.g., the mitochondrial yield from 4 mg of rat liver) has been made possible by t...

We have investigated escape behaviour of workers of two bumblebee species, Bombus terrestris and B. pascuorum, when confined to test tubes plugged with soil and either exposed to sunlight or kept in darkness. In both these situations B. terrestris performed better (i.e. escaped after a shorter time) than B. pascuorum. B. terrestris (but not B. pascuorum) also performed better in darkness than i...

Xiphinema llanosum n. sp. and Trophurus vultus n. sp. are described and illustrated from grass soils in Llanos Orientales, Colombia. Xiphinema llanosum is a bisexual species. The female body length is 2.3-2.7 mm, odontostyle 86-96 mum, and odontophore 58-65 mum long; vulva at 42-47%; anterior ovary is absent; the anterior uterus and oviduct are similar to the posterior branch but slightly reduc...

A number of bacteriological and serological procedures require the use of a series of test tubes. The size of the tubes, as well as the racks used to hold the tubes, may vary. Tubes 12 to 15 mm in diameter and 75 to 100 mm in length are most commonly used. observed at one time. Ambidextrous people can become quite adept at this, while others constantly appear to have five thumbs. With the prove...

Research in extremely delicate environments must be sensitive to the need to minimize impacts caused simply through the presence of research personnel. This study investigates the effectiveness of current advice relating to travel on foot over Antarctic vegetation-free soils. These are based on the concentration of impacts through the creation of properly signed and identified paths. In order t...

The influence of sample size on the magnitude and variability of soil denitrification was studied by collecting soil cores, ranging in size from 1.7 to 5.4 cm in diameter, from no-till and conventionaltill corn plots. Estimates of natural denitrification rates were obtained by incubating intact soil cores with C2H2 and monitoring gaseous N2O production. In addition, maximum denitrification pote...

PURPOSE To examine the history of pediatric endotracheal intubation and the issues surrounding the change from uncuffed endotracheal tubes to cuffed endotracheal tubes, including pediatric airway anatomy, endotracheal tube design, complications, and safety concerns. METHOD Review of the literature. CONCLUSIONS Although the use of cuffed endotracheal tubes in infants and children remains a t...