Lubrication and Wear Analysis of a Novel Squeeze Film Artificial Hip Joint

Conventional artificial hip joints are characterized by inadequate `wedge film\u27 lubrication due to cyclic non-reversing loading and low frequency oscillatory ball motion. A novel `squeeze film\u27 design concept is presented which employs elastic restoring action and ellipsoidal cup geometry to enact separation of the bearing surfaces and improve lubrication behavior. Lateral and in-line design configurations were developed and analyzed using established finite element lubrication models with realistic gait cycle and bearing design specifications likely to be found in practice. An Archard-based wear formulation that relates contact pressure and sliding distance to linear wear depth was applied to the design configurations utilizing ANSYS to investigate the wear characteristics of the novel implant design. From a lubrication perspective, it was found that significantly larger minimum film thicknesses and significantly smaller maximum film pressures are predicted over the stance phase when compared with conventional designs, while complete reformation of the lubricant film is predicted over the swing phase of the gait cycle. From a wear perspective, it was found that low-modulus elastic elements with bonded high-modulus metal coatings offer significant improvement in volumetric wear rates and maintain acceptable levels of linear wear rates when compared with conventional implant geometries

Wear Assessment of a Novel Squeeze-Film Artificial Hip Joint

Poster shows motivation, features of design, characterization of wear and predicted results for artificial hip joint

The White Heather

https://digitalcommons.library.umaine.edu/mmb-vp/6759/thumbnail.jp

Endogenous Retrovirus Insertion in the KIT Oncogene Determines White and White spotting in Domestic Cats

The Dominant White locus (W) in the domestic cat demonstrates pleiotropic effects exhibiting complete penetrance for absence of coat pigmentation and incomplete penetrance for deafness and iris hypopigmentation. We performed linkage analysis using a pedigree segregating White to identify KIT (Chr. B1) as the feline W locus. Segregation and sequence analysis of the KIT gene in two pedigrees (P1 and P2) revealed the remarkable retrotransposition and evolution of a feline endogenous retrovirus (FERV1) as responsible for two distinct phenotypes of the W locus, Dominant White, and white spotting. A full-length (7125 bp) FERV1 element is associated with white spotting, whereas a FERV1 long terminal repeat (LTR) is associated with all Dominant White individuals. For purposes of statistical analysis, the alternatives of wild-type sequence, FERV1 element, and LTR-only define a triallelic marker. Taking into account pedigree relationships, deafness is genetically linked and associated with this marker; estimated P values for association are in the range of 0.007 to 0.10. The retrotransposition interrupts a DNAase I hypersensitive site in KIT intron 1 that is highly conserved across mammals and was previously demonstrated to regulate temporal and tissue-specific expression of KIT in murine hematopoietic and melanocytic cells. A large-population genetic survey of cats (n = 270), representing 30 cat breeds, supports our findings and demonstrates statistical significance of the FERV1 LTR and full-length element with Dominant White/blue iris (P \u3c 0.0001) and white spotting (P \u3c 0.0001), respectively

Distorted maternal mental representations and atypical behavior in a clinical sample of violence-exposed mothers and their toddlers

Objective: To determine whether maternal violence-related posttraumatic stress disorder (PTSD), reflective functioning (RF), and/or quality of mental representations of her child predicts maternal behavior within a referred sample of mothers exposed to interpersonal violence and their children (aged 8–50 months). Method: A total of 41 dyads completed 2 videotaped visits including measures of maternal mentalrepresentations and behavior. Results: Negative and distorted maternal mental representations predicted atypical behavior (Cohen’s d \u3e 1.0). Although maternal PTSD and RF impacted mental representations, no significant relationships were found between PTSD, RF, and overall atypical caregiving behavior. Severity of maternal PTSD was, however, positively correlated with the avoidant caregiving behaviorsubscale. Conclusions: Maternal mental representations of her child are useful risk indicators that mark dysregulation of trauma-associated emotions in the caregiver

The Influence of Nursing Experience and Education on Nurses Inferences of Patients\u27 Suffering

A primary dimension of nursing is caring tor patients who suffer. This study examined the inferences made about patients\u27 suffering oy 65 registered nurses employed in acute care health facilities. Utilizing The standard Measure of Inferences of Suffering Questionnaire. the purpose of the study was to explore the influence of nursing education and experience on the degree of pain and psychological distress inferred by the nurses. Analysis of Covariance was used to test for group differences on the basis of nursing education when number of months of nursing experience was controlled. Although nursing education did not influence nurses\u27 inferences of patients· suffering. Pearson correlations revealed an inverse relationship between the amount of experience and the degree of inferred suffering, such that as the amount of nursing experience increased. the degree of inferred suffering decreased. Further research exploring different variables involved in perception and subsequent inferences of patients\u27 suffering is recommended