Theoretical model for the wetting of a rough surface.

Many applications would benefit from an understanding of the physical mechanism behind fluid movement on rough surfaces, including the movement of water or contaminants within an unsaturated rock fracture. Presented is a theoretical investigation of the effect of surface roughness on fluid spreading. It is known that surface roughness enhances the effects of hydrophobic or hydrophilic behavior, as well as allowing for faster spreading of a hydrophilic fluid. A model is presented based on the classification of the regimes of spreading that occur when fluid encounters a rough surface: microscopic precursor film, mesoscopic invasion of roughness and macroscopic reaction to external forces. A theoretical relationship is developed for the physical mechanisms that drive mesoscopic invasion, which is used to guide a discussion of the implications of the theory on spreading conditions. Development of the analytical equation is based on a balance between capillary forces and frictional resistive forces. Chemical heterogeneity is ignored. The effect of various methods for estimating viscous dissipation is compared to available data from fluid rise on roughness experiments. Methods that account more accurately for roughness shape better explain the data as they account for more surface friction; the best fit was found for a hydraulic diameter approximation. The analytical solution implies the existence of a critical contact angle that is a function of roughness geometry, below which fluid will spread and above which fluid will resist spreading. The resulting equation predicts movement of a liquid invasion front with a square root of time dependence, mathematically resembling a diffusive process.

A reexamination of the substrate utilization of 2-thioorotidine-5'-monophosphate by yeast orotidine-5'-monophosphate decarboxylase.

A potential alternate substrate for orotidine-5'-monophosphate decarboxylase, 2- thio-orotidine-5'-monophosphate, was synthesized enzymatically and purified by a modification of a previous account (K. Shostak, and M. E. Jones 1992, Biochemistry 31, 12155-12161). Characterization of the product was confirmed by mass spectrometry, (31)P NMR, and utilization by orotate phosphoribosyltransferase in the direction of pyrophosphorolysis. The previous work probably did not result in the purification of the desired compound, as evidenced by our observation of 2-thioOMP's sensitivity to high temperature, as used previously. Using a very sensitive HPLC assay for the potential decarboxylated product 2-thioUMP, no measurable activity of ODCase toward the alternate substrate was observed, representing a decarboxylation rate decreased by 10(-7) from the k(cat) for ODCase toward OMP. Additionally, 2-thioOMP effects no inhibition of ODCase decarboxylation of OMP at a concentration of 50 microM, indicating a poor ability to bind to the ODCase active site. The results bear implications for proposed mechanisms for catalysis by ODCase.

Primary care parish nursing: academic, service, and parish partnership.

Health care providers who want to make a difference in today's health care environment must support the idea of collaboration. To address the concerns of a university, a major medical center, and the community, a collaborative group shared their vision and developed creative strategies to serve the community. The critical components of this project included gaining the services of a nurse practitioner and nurse case manager, establishing physician liaison, assessing congregational health care needs, providing for both primary health and continuity of care needs, and maintaining the spiritual component of the faith community. Essential to the success of this program was the achievement of pastor and congregational support, enthusiasm, and involvement.

1044 women with migraine: the effect of environmental stimuli.

This study initiated by a self-help migraine group investigated disability caused by visual environmental stimuli, e.g. glare, flicker, pattern and color. One thousand forty-four women with migraine completed the self-report questionnaire on visual environmental stimuli reported in earlier studies to precipitate or aggravate migraine. One hundred twenty-one female controls were obtained from general practice and hospital out-patients. The responses of the classical, common and non-migraine groups were compared. Women with classical migraine expressed greater disability than those with common migraine or controls both in respect of number of visual sensitivities reported (P < 0.0001) and severity of consequences of such stimuli (P < 0.0001). This study indicated differences between classical and common migraine outside of the attack phase apart from aura. Reported range of sensitivities for the migraineurs peaked between the ages of 46-60 years. A high level of unrealized disability caused by visual environmental stimuli was thus identified in hitherto unexplored self-help groups.

The treatment of pain trigger areas in migraine.

In many patients with migraine, several localised areas usually on the scalp or neck can be identified. The local injection of lignocaine one per cent and adrenaline 1/200,000 often leads to considerable relief of the symptoms of migraine including visual phenomena. The common sites of the trigger areas are shown and several uncontrolled case reports of the effect of the treatment are described.