Thin-film theories for two-phase reactive flow models of active cell motion.

The aim of this paper is to develop a broadly-applicable and self-consistent thin-film biphasic modelling framework for the full crawling cycle of a single animal cell. A hierarchy of thin-film two-phase 'reactive flow' models is derived; between them these cover a wide range of biologically relevant parameter regimes. The mathematical properties and biological implications of the resulting systems of high-order nonlinear degenerate parabolic-elliptic evolution equations are investigated. Linear-stability arguments suggest the formation of highly localized regions of high or low network density associated with small irregular oscillations or 'ruffling' of the plasma membrane. Local analyses at the contact line identify the classes of admissible contact-line conditions, through which we study for the first time the effect on the cell-scale motion of the 'mesoscopic' contact-line physics, which consists of the chemical and mechanical mechanisms for protrusive and retractive force generation near the outer cell periphery. One of the formulations is used to develop a minimal model for cell body translocation over a thin pseudopod, which predicts that myosin-driven contraction is not essential for rapid translocation. An analytic prediction for the translocation speed is given in terms of the network viscosity and slip coefficient (a parameter measuring the adhesion strength), of the membrane tension and of the thicknesses of the pseudopod and actin cortex; this is in good agreement with the translocation speed of osteoblasts on biomaterial substrates commonly used for orthopaedic implants. Limitations of the modelling approach and directions for future work are outlined.

Compliance with chemotherapy among breast cancer patients.

This study explored the extent of and reasons for noncompliance with intravenously-administered chemotherapy among a sample of breast cancer patients. Overall, chemotherapy compliance was high (92%). The few cases of non-compliance identified were indirect. In particular, two patients rejected chemotherapy outright and two alcoholic patients used alcohol to avoid chemotherapy. The high rate of chemotherapy compliance was judged to be due to its perceived centrality to recovery from cancer, the "medical" nature of its administration, the ease with which non-compliance can be detected, and patients' spontaneous use of successful coping techniques.

Self-esteem and the cognitive accessibility of strengths and weaknesses after failure.

People with high self-esteem (HSEs) respond less negatively to failure than people with low self-esteem (LSEs). This difference may occur because HSEs overcome the natural tendency to focus on negative thoughts after failure, and instead focus on their strengths. In 2 experiments, participants with high and low self-esteem received failure, success, or no feedback. Accessibility of strengths and weaknesses was measured by response latency on an unrelated task. Results confirmed that although strengths were typically more accessible than weaknesses for both groups, the discrepancy was larger for HSEs after failure feedback than after no feedback. This heightened discrepancy appears to result from HSEs recruiting their strengths and suppressing their weaknesses. In contrast, LSEs' weaknesses appeared to become especially accessible after failure. These results have implications for the mood-congruent cognition and self-esteem literatures.

Downward comparison in everyday life: reconciling self-enhancement models with the mood-cognition priming model.

Two models concerning downward comparison are motivational; they predict that when people are unhappy, they make downward comparisons to self-enhance (e.g., Wills, 1981). In contrast, the affect-cognition priming model (Wheeler & Miyake, 1992) predicts that unhappy people make upward comparisons because negative affect makes mood-congruent comparisons more accessible. The authors propose that both motivational and accessibility factors influence social comparisons. A study of undergraduates' self-recorded everyday comparisons supported this view. In addition, results (a) pointed to motivational influences other than self-enhancement and an accessibility influence other than mood-congruent priming, (b) suggested that motivated and unintended comparisons may differ somewhat in their susceptibility to motivational and accessibility influences, and (c) identified challenges to both self-enhancement and priming models.

Depressive personality styles, dysphoria, and social comparisons in everyday life.

"Sociotropic" people are supposedly vulnerable to dysphoria after negative interpersonal events, whereas "autonomous" people are supposedly vulnerable to achievement-related failures. The present study examined whether these personality styles are borne out in social comparison processes. For 3 weeks, 27 sociotropic and 35 autonomous undergraduates completed records of their social comparisons. Depressive personality style moderated comparison frequency and the affective consequences of comparisons, especially for dysphoric individuals: Dysphoric respondents were especially likely to make comparisons in domains that were congruent with their personalities, and comparisons in congruent domains were associated with greater mood change than comparisons in other domains, perhaps especially for dysphoric respondents. These results have implications for the literatures on social comparison and on depressive personality styles.

Social comparison in adjustment to breast cancer.

We investigated four theoretical perspectives concerning the role of social comparison (Festinger, 1954) in coping with a threatening event in a sample of breast cancer patients. According to the supercoper perspective, personal contact with comparison others is often unavailable to patients, and contact with media "supercopers"--fellow victims presented as adjusting very smoothly--may make patients feel inadequate by comparison. According to the similarity perspective, patients select comparison targets who are similar to themselves because those comparisons should be the most informative. The upward comparison perspective is predictive of comparisons to relatively advantaged or superior individuals. The downward comparison perspective leads to the prediction that under conditions of threat, individuals make comparisons to people who are inferior or less fortunate in order to enhance their self-esteem. We interviewed 78 breast cancer patients, and results of both closed-ended questions and spontaneously offered comparisons yielded a preponderance of downward comparisons. The results point to the value of using naturalistic methods for studying comparisons, and suggest a more active and cognitive role for social comparison than is usually portrayed.

Does affect induce self-focused attention?

Despite growing evidence that depression is linked with self-focused attention, little is known about how depressed individuals become self-focused or, more generally, about what arouses self-focus in everyday life. Two experiments examined the hypothesis that affect itself induces self-focused attention. In Experiment 1, moods were manipulated with an imagination mood-induction procedure. Sad-induction Ss became higher in self-focus than did neutral-induction Ss. Experiment 2 replicated this effect for sad moods by means of a musical mood-induction procedure and different measures of self-focus. However, Experiment 2 failed to support the hypothesis that happy moods induce self-focus. The results have implications for mood-induction research, self-focused attention, and recent models of depression.

Attributions, beliefs about control, and adjustment to breast cancer.

Attributions for cancer and beliefs about control over cancer were examined for their association with adjustment to breast cancer. Although 95% of the respondents made attributions for their cancer, no particular attribution (e.g., stress, diet) was associated with better adjustment. Analyses of attributions of responsibility for the cancer to the self, environment, another person, or chance yielded only a negative relation between adjustment and blaming another person. In contrast, both the belief that one could now control one's cancer and the belief that others (e.g. the physician) could now control the cancer were significantly associated with good adjustment. Of the different types of control, cognitive control was most strongly associated with adjustment, behavior control was less strongly associated with adjustment, and information control and retrospective control were unassociated with adjustment. The theoretical and practical implications of these results are discussed.

Self-focused attention, coping responses, and distressed mood in everyday life.

Several questions concerning the relation between self-focused attention and depressed mood were examined: (a) Does the association involve global negative affect, rather than sadness per se? (b) is self-focus associated with specific negative affects other than sadness? and (c) does the association occur at the between-subjects or within-subject level? Also hypothesized was that self-focus is associated with coping responses that may perpetuate negative mood. In an idiographic/nomothetic design, 40 male community residents completed daily reports for 30 days. Results suggest that self-focus is linked with global negative mood as well as specific negative affects other than sadness and that the association occurs on a between-persons, rather than a day-to-day within-person, basis. In addition, highly self-focused men reported using passive and ruminative coping styles, which in turn were associated with distressed affect.

Strategies of social comparison among people with low self-esteem: self-protection and self-enhancement.

People with low self-esteem (LSE) seem to focus on self-protection; rather than trying to achieve gains for their self-esteem, they try to avoid losses. This research examined, in a social comparison context, the hypothesis that LSEs seek self-enhancement when they have an opportunity that is "safe," that is, carrying little risk of humiliation. Experiments 1 and 2 indicated that LSEs sought the most social comparisons after receiving success feedback, whereas high-self-esteem Ss (HSEs) sought the most comparisons after failure. Further results suggested that LSEs who succeeded were seizing a safe means of self-enhancement and that HSEs who failed were seeking to compensate for the failure. Also supporting this interpretation for LSEs was Experiment 3, in which LSEs who succeeded sought the most comparisons when such comparisons promised to be favorable. All three studies illustrate the value of a new measure of social comparison selection.

Effects of surface-treated cpTi and Ti6Al4V alloy on the initial attachment of human osteoblast cells.

This study concerns the effect of simple surface treatments on the nature of the oxide layer, of commercially pure titanium (cpTi) and Ti6Al4V alloy substrates and their effect on human osteoblast cells (HOBS). After treatment the surfaces were analyzed by X-ray photoelectron spectroscopy (XPS) in order to identify the surface groups responsible for the cell attachment process. The assessment of cell attachment was monitored by the Alamar blue assay (AB), measuring cell activity, in three types of media: phosphate-buffered saline (PBS), serum containing and serum-free Dulbecco's modified Eagle's cell culture medium (SER+ and SERF respectively). XPS analysis of the treated surfaces revealed consistent peaks representative of TiO2 on all surfaces and Ti(0) and Ti2O3 on the non-heat-treated surfaces. The cell activity assays indicated that there were no significant differences in cellular activity caused by surface treatments, but the cellular activity compared between the three types of medium was greatest in the PBS over the initial stages of attachment.

Illness-related and treatment-related factors in psychological adjustment to breast cancer.

Seventy-eight breast cancer outpatients were interviewed and their medical records were reviewed to document illness-related and treatment-related factors associated with psychosocial adjustment. Poor prognosis and more radical surgery both independently predicted poor psychological adjustment. The effect of type of surgery appeared to be mediated by the patient's sense of disfigurement and by changes in the sexual and affectional patterns in the marriage, rather than by prognosis or disability. Degree of dysfunction and whether or not the patient had radiation therapy or chemotherapy had no independent effects on psychological adjustment. Results point to the problematic psychosocial outcomes associated with mastectomy and, more generally, to the illness- and treatment-related factors that may place a breast cancer patient at risk for psychosocial adjustment problems.

Breast self-examination among diagnosed breast cancer patients.

The practice of breast self-examination (BSE) was explored by personal interview in a sample of women with diagnosed breast cancer. Despite physician recommendations to practice BSE, only 43% of those interviewed were examining themselves regularly, a figure that is little different from that of the general population. Predictors of BSE were age (older women were less likely to practice) and practice of BSE before diagnosis. Factors contributing to nonpractice were judged to be: (1) the patients' beliefs that occasional examinations by physicians are a sufficient substitute for BSE; (2) the patients' perceptions that BSE is discretionary and not truly "medical"; and (3) the fact that BSE may raise patients' anxiety over cancer without affecting its likelihood. It was concluded that the practice of BSE among diagnosed patients could be increased if physicians stress its importance and provide systematic instruction or reinstruction in its practice.