PubMed Health⌕ Search

Biomedical subjects

J Texter

Publications and source records attributed to J Texter.

8 recordsLinked to original sources
PubMed1999

Adsorption of N,N-Diethyldodecanamide at the Air-Water Interface.

The adsorption of N,N-diethyldodecanamide (DEDA) at the air-water interface has been determined at 24 degrees C by surface tension measurements. At monolayer saturation each molecule has a surface area, depending on the equation of state assumed, of about 41.2-45.6 Å(2), comparable to that observed for sodium dodecyl sulfate and other somewhat similar surfactants. Micellization of DEDA appears not to occur below its aqueous saturation concentration of 1.4 x 10(-5) M. At saturation the surface tension is lowered to 37 dyn cm(-1), and the standard free energy of adsorption is about -46.5 kJ mol(-1). The surface adsorption deviates slightly from the Szyszkowski-Langmuir surface equation of state at coverages below 50%, and a two-state adsorption mechanism proposed by Lunkenheimer and Hirte appears to best account for this deviation. Copyright 1999 Academic Press.

Journal Article↗
PubMed1998

Effect of hyperbaric oxygen therapy on testicular ischemia-reperfusion injury.

PURPOSE: Testicular torsion is a urologic emergency representing a form of ischemia-reperfusion (IR) injury that requires prompt care to achieve tissue salvage and a reduction in post-torsion morbidity. Hyperbaric oxygen (HBO) has shown benefits in previous musculoskeletal models of IR. We evaluated the efficacy of HBO treatment in a rat testicular torsion model. MATERIALS AND METHODS: Four groups of male Wistar rats were included in this study: 1) Sham (n=16), spermatic cords exposed but not occluded; 2) Control (n=16), 4 hours of bilateral spermatic cord occlusion; 3) HBO during ischemia (n=18), 4 hours of occlusion and administration of HBO during the last 90 minutes of ischemia; and 4) HBO on reperfusion (n=8), HBO administered immediately upon reperfusion of the testes. The animals were sacrificed at two weeks and architecture and germinal epithelial cell thickness were determined by histological examination on each testicle. Average thickness (in cell layers) of each group was compared with control using Student's t test. RESULTS: Control testicles showed a significant reduction in germinal cell thickness compared with sham (1.7 versus 6.3, p <0.05). The animals treated with HBO during ischemia showed a significant increase in epithelial cell thickness compared with control (2.8 versus 1.7, p <0.05). Hyperbaric oxygen treatment during reperfusion had the greatest beneficial effect compared with control (5.1 versus 1.7, p <0.05). CONCLUSIONS: Adjunctive HBO therapy administered during ischemia or reperfusion significantly reduced injury to the testicle in this animal model. These results suggest a potential benefit of HBO treatment in clinical situations of testicular torsion.

Analysis of Variance↗
PubMed1992

Quantum yield for preferential photodimerization in long pyrimidine tracts.

The quantum yield for cyclobutyl-pyrimidine dimerization in DNA has been observed to increase approximately linearly with increasing pyrimidine tract length. A model without adjustable parameters for this yield is proposed based on energy delocalization, vibronic symmetry switching, and saturation statistics that describe the average number of (base pairwise) breathing modes in a given tract of pyrimidines. This average number of modes is an approximately linear function of the tract length. Monte Carlo techniques are used to simulate base sequences and photochemical events, and indicate that this model is consistent with experiment for Tetrahymena pyriformis DNA.

Animals↗
PubMed1990

Saturation photodimerization of thymines in DNA.

Acetophenone sensitizes the uv photodimerization of adjacent thymines in nucleic acids and under steady state irradiation induces irreversible saturation dimerization. Monte Carlo and analytical techniques are used to calculate the saturation dimerization limits for various nucleic acids, under the assumption that acetophenone-sensitized dimerization occurs by a random irreversible process. A comparison of these calculated results with experimental values indicates that sensitized dimerization occurs by an effectively random process only in single-stranded DNA or in native DNA of very high A.T content. In general, nucleation phenomena operate in native DNA that serve to stereochemically restrict saturation dimerization limits below those expected for random dimerization.

Acetophenones↗