Desalting, concentration, and buffer exchange by dialysis and ultrafiltration.

This unit includes a variety of dialysis and ultrafiltration techniques that can be used for desalting, concentration, or buffer exchange. Standard dialysis by diffusion across cellulose tubing is described as a technique for desalting or buffer exchange. Ultrafiltration under pressure can be used either for concentrating protein or, where the sample volume is replenished with a desired buffer, for desalting/buffer exchange (i.

Mechanical disruption of Escherichia coli for plasmid recovery.

Five different mechanical cell disruption processes were evaluated as methods to extract plasmids from bacterial cells. The methods used were sonication, nebulization homogenization, microfluidization, and bead milling. The recovery yields of intact plasmids from the various methods were measured by quantitative gel electrophoresis.

Comparison of pediatric end-tidal CO2 measured with nasal/oral cannula circuit and capillary PCO2.

This study was designed to determine whether end-tidal carbon dioxide (ETCO2) values obtained by noninvasive oral/nasal cannula circuit with side-stream capnometry correlate reliably with capillary PCO2 (CapCO2) in a pediatric population without cardiopulmonary problems. Each patient was monitored until a reliable 5-minute ETCO2 waveform was obtained. A capillary blood gas sample was drawn while, simultaneously, ETCO2 was recorded.

Obstructive jaundice associated with polysplenia syndrome in an older child.

Polysplenia syndrome includes malrotation and various forms of heterotaxy. Associated with this and malrotation are extrahepatic biliary anomalies. Actual obstruction, other than in associated biliary atresia, is extremely rare, and rarer still in older children.