Cotton thread method for measuring tear secretion, suitable for soft contact lens wearers (method no. 3)

Two methods of measuring lacrimation with a cotton thread and fluorescein have been described hitherto. Method 3 is intended for testing lacrimal flow in wearers of soft contact lenses. Fluorescent paper can be used to facilitate the measuring procedure. The method has been shown to be reliable in numerous control tests on subjects with normal eyes and in comparisons with the authors' methods 1 and 2. With the test, values of less than 5 mm indicate severe lacrimal deficiencies.     

Multifocal ERG with the scanning laser ophthalmoscope: query on the ideal configuration for attaining high resolution and result stability

Graefe's Archive for Clinical and Experimental Ophthalmology -     

Analysis of three-dimensional sinter shrinkage of copings made from alumina in an innovative direct shaping process.

The three-dimensional (3D) evaluation and comparison of free-form-surfaces is a complex problem [Dent. Mater. 8 (1992) 49; J. Dent. Res. 76 (1997) 1799; Dent. Mater. 16 (2000) 145; J. Prosthet. Dent. 70 (1993) 457; Dent. Mater. 19 (2003) 19]. However, it is essential in order to analyze the sinter shrinkage of dental ceramic-restorations where isotropic and linear shrinkage is desired for accurate fit on the prepared teeth. In this article, we examine the 3D sinter shrinkage in general and for nine copings from alumina in particular. Using various scaled CAD-models in an iteration scheme, each model was compared to the filtered point cloud of the coping, determining the surface-cloud difference. The magnitude of deviations from linear sinter shrinkage was investigated. Furthermore, a new fabrication process for ceramic-restorations is introduced.     

The reduction of methemoglobin levels by antioxidants

Preventing the oxidation of hemoglobin in solution is one of the major requirements for the successful production and long-term storage of hemoglobin-based blood substitutes. To this end we have studied the effects of antioxidants on the rate of methemoglobin formation and disappearance in solutions of human and bovine hemoglobin at 4 degrees C and 37 degrees C. Ascorbate and desferal (5 mM) were observed to act as prooxidants, increasing the rate of methemoglobin formation at 37 degrees C. Trehalose, mannitol, glucose, and EDTA (5 mM) had no significant effect. Glutathione and NADH (10 mM) were the most effective antioxidants tested, causing a significant decrease in the rate of methemoglobin formation at 37 degrees C for periods of up to 50 hours. The combination of these antioxidants in bovine hemoglobin at 4 degrees C resulted in the reduction of methemoglobin levels to nearly undetectable levels in approximately 150 hours. In addition, NADH and glutathione were found to reduce methemoglobin levels to 10% over a period of 100 hours in a sample of human hemoglobin that had been stored at 4 degrees C for one year and had 60% methemoglobin. These results suggest that the prevention and reversal of methemoglobin formation during the long-term storage of hemoglobin solutions and hemoglobin-based blood substitutes may now be possible.     

Nutritional implications of L-arabinose in pigs.

The pentose sugar L-arabinose is one of the most abundant components released by complete hydrolysis of non-starch polysaccharides of feed ingredients of vegetable origin. Two studies were conducted to investigate the apparent ileal digestibility and urinary excretion of L-arabinose at dietary inclusion levels of 50 and 100 g/kg, and 25, 50, 75 and 100 g/kg respectively, in pigs. As a reference, D-glucose was included in the studies. Water intake, ileal flow of volatile fatty acids and ileal and faecal digestibilities of dietary nutrients in pigs fed on the different diets were also examined. Castrated pigs were prepared with a post-valvular T-caecum cannula to measure ileal digestibility. Faecal digestibility was measured in non-cannulated pigs. Apparent ileal digestibility of L-arabinose was found to be approximately 70%. The presence of L-arabinose in the diet increased ileal flow of volatile fatty acids and lactic acid, suggesting the occurrence of microbial degradation of L-arabinose in the pig small intestine. L-arabinose was partly excreted in the urine. The extent of this urinary excretion as a percentage of intake increased linearly (P < 0.01) as the dietary level increased. In pigs fed on the 25 g L-arabinose/kg diet, 10.9% of the L-arabinose consumed appeared in the urine. This level was increased to 14.7% when pigs were fed on a diet containing 100 g L-arabinose/kg diet. Faecal digestibility and retention of nitrogen decreased significantly in pigs fed on the L-arabinose diets.     

Construct Validity of a Clinical-performance-evaluation Tool in Community Health Nursing

An evaluative research study was conducted to examine the construct validity and applicability of a selected clinical-performance-evaluation tool. The tool was designed for baccalaureate students in a community health nursing course. Eighteen senior students functioning in two urban clinical agencies participated in the study. Data were collected at two evaluation points over one semester. Results indicated strong support for construct validity of the tool. This finding suggests a high level of correlation between theoretical concepts and clinical practice. Recommendations for use of the clinical performance evaluation tool are discussed.