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Peter Janknecht

Publications and source records attributed to Peter Janknecht.

3 recordsLinked to original sources
PubMed2004

Removal of industrial cutting oil from oil emulsions by polymeric ultra- and microfiltration membranes.

The utilization of micro- and ultrafiltration with polymeric membranes for treatment of industrial cutting oil emulsion was investigated. The performance of 14 different membranes with pore sizes in the range of 1-800 nm, representing 8 different materials and varying hydrophobicity, was determined experimentally. Membrane permeances between 1.6 and 939 L m 2 h(-1) bar(-1) have been observed for the different samples as well as oil rejections between 3.42% and 99.99%. Membrane pore size and contact angle showed little influence on both values, while an interesting correlation is displayed to the individual membranes' capillary pressures. A possible explanation for this phenomenon is suggested based on the formation of oil films on the membrane surface. From the investigated membranes, the best-suited one for cutting oil treatment was selected and subjected to further experiments. The effect of process temperatures between 22 and 43 degrees C and of feed oil concentrations between 0 and 20 vol % on the removal performance was determined. The results correspond to the explanation suggested previously.

Emulsions↗
PubMedDate not supplied

Enzyme-assisted vitrectomy in enucleated pig eyes: a comparison of hyaluronidase, chondroitinase, and plasmin.

PURPOSE: Facilitation of vitrectomy by vitreolytic enzymes may be of great value in complicated or office-procedure vitreo-retinal surgery. In this study, we quantified and compared the effect of hyaluronidase, chondroitinase, and plasmin pre-incubation on vitrectomy rate and explored potential retinal damage. METHODS: Freshly enucleated pigs eyes were incubated (1 or 3 hours) with an intravitreally injected enzyme or control solution. Enzyme doses were 100 and 1000 U for hyaluronidase, 1 and 2 U for chondroitinase, 3 and 30 U for plasmin. The eyes were weighed before and after 10 minutes of one-port vitrectomy, the difference representing the amount of removed vitreous. Light microscopy was used to assess potential damage to the retina. RESULTS: All enzymes significantly increased the amount of removed vitreous at all doses and incubation periods. The highest increase was found with hyaluronidase 1000 U, 3 hours, the lowest with chondroitinase 1 U, 1 hour. Damage occasionally occurred to the internal limiting membrane and very rarely to the nerve fiber layer. No damage at all was seen in the 100 and 1000 U hyaluronidase (1-hour incubation) groups. CONCLUSIONS: Hyaluronidase, chondroitinase, and plasmin are good candidates for enzyme-assisted vitrectomy. Although retinal structural damage was very rarely seen, safety concerns will have to be investigated further.

Animals↗