Management of perineal and genital burns

Burn injuries to the perineum and genitals present the bedside care provider with a unique set of management problems. Traditionally, thermal injuries to these areas have been allowed to close by secondary intention, with epithelialization occurring from remnants protected within skin folds. Partial-thickness wounds of the perineum and genitals must be kept clean and free of bacterial infection to prevent necrosis and development of full-thickness injury. Although full-thickness thermal injuries to the penis and vulva are rare, they require special attention during the immediate postgrafting period to ensure complete engraftment. Control of scarring in this area requires tailor-made pressure garments, with customized inserts to provide controlled pressure to the skin folds.     

Wetting of octadecylsilylated silica in methanol-water eluents

The wetting of an octadecylsilylated silica in methanol-water mixtures was studied by optical transmittance, visual observations, and measurements of the retention of model compounds. The octadecylsilylated silica particles remain wetted as the methanol content is decreased from 100% (v/v) to 20% (v/v). With the methanol content in the range of 20% (v/v) to 10% (v/v), the octadecylsilylated silica particles are still wetted, but the degree of solvation of the C(18) chains decreases with decreasing methanol concentration. The octadecylsilylated silica particles are not wetted when the methanol content in the mobile phase is lower than 10% (v/v). After equilibration with water, the octadecylsilylated silica particles remain nonwetted until the methanol content reaches 65% (v/v). The nonwetted phase showed significantly reduced chromatographic retention. A much longer equilibration time is required when the octadecylsilylated silica particles are not well solvated or nonwetted. The retentive behavior of the column will depend on the history of mobile-phase exposure.     

Studies of liquid-phase complexes in acetonitrile/water solutions by attenuated total reflection infrared spectroscopy with acetaldehyde as a model solute

Chemometric methods combined with infrared (IR) spectroscopy, using attenuated total reflectance (ATR) sampling, are employed here to characterize the stoichiometry of complexes of solvent molecules in the liquid phase. The spectral information provides insight into the liquid microstructure present in liquid chromatographic mobile phases. This information should make it easier to understand and predict the effects of changes in mobile phase composition on the results of chromatographic separations. In this paper, mobile phases consisting of 0 mol % to 100 mol % acetonitrile in water were studied, with the addition of acetaldehyde as a model solute at concentrations ranging from 3 to 8 mol %. Using three-way multivariate curve resolution by the alternating least squares method (MCR-ALS) it was possible to resolve eight unique spectra: four mobile phase components, and four unique spectra of acetaldehyde solvated in different environments. The directions of the shifts of the important acetaldehyde infrared bands show good correlation with those predicted by gas-phase ab initio calculations of small solvated clusters.