4 research outputs found
Analytical solution of generalized Burton--Cabrera--Frank equations for growth and post--growth equilibration on vicinal surfaces
We investigate growth on vicinal surfaces by molecular beam epitaxy making
use of a generalized Burton--Cabrera--Frank model. Our primary aim is to
propose and implement a novel analytical program based on a perturbative
solution of the non--linear equations describing the coupled adatom and dimer
kinetics. These equations are considered as originating from a fully
microscopic description that allows the step boundary conditions to be directly
formulated in terms of the sticking coefficients at each step. As an example,
we study the importance of diffusion barriers for adatoms hopping down
descending steps (Schwoebel effect) during growth and post-growth equilibration
of the surface.Comment: 16 pages, REVTeX 3.0, IC-DDV-94-00
Prevalence and correlates of mental health problems in prostate cancer survivors: A case control study comparing survivors with general population peers
Objective The purpose of this study was to identify factors associated with mental health (MH) problems in prostate cancer (PC) survivors. Toward this end, we evaluated (1) differences in the prevalence of MH problems between PC survivors and age-matched men from the general population (GenPop) and (2) correlates of MH in PC survivors and the GenPop. Methods and materials In this observational case-control study, we age-matched PC survivors (n = 644, alive≥5 y after diagnosis of a stage I–IV carcinoma) recruited from Dutch community hospitals (Patient Reported Outcomes Following Initial treatment and Long-term Evaluation of Survivorship registry) with GenPop peers (n = 644) selected from a population-based sample recruited in general practices (NIVEL). MH was operationalized using the 5-item Mental Health Inventory of the Short Form Health Survey (SF-36). Potential correlates of MH included sociodemographic characteristics, health-related quality of life scores, and clinical characteristics (PC survivors only). We used analysis of (co)variance and chi-square tests to address the 2 research questions. Results We observed clinically relevant MH symptoms in 14% of the PC survivors and 6% of the GenPop controls (P<0.01, odds ratio = 2.45 [1.66–3.62]). The most important correlates of lower MH scores in the PC survivors were being widowed, a lower educational level, lower general health perceptions, more bodily pain and urinary bother, and less sexual satisfaction. The most important correlates of lower MH scores in the GenPop were as follows: lower general health perceptions, more role limitations because of physical problems, and more bodily pain. Conclusions Our results indicate that long-term PC survivors have poorer MH, as assessed by the 5-item Mental Health Inventory questionnaire, than men of a comparable age from the GenPop without a history of PC. Attention to potentially modifiable factors associated with MH problems in PC survivors, such as urinary function and its related bother, bodily pain, and sexual satisfaction, may help to prevent or limit MH problems in this survivor population
The Effect of Salvage Radiotherapy and its Timing on the Health-related Quality of Life of Prostate Cancer Patients
Background The impact of salvage radiotherapy (SRT) and its timing on health-related quality of life (HRQoL) in prostate cancer patients is still unclear. Objective To compare the HRQoL of patients who underwent SRT with that of patients who underwent radical prostatectomy (RP) only and to investigate whether SRT timing is associated with HRQoL. Design, setting, and participants All SRT patients (n = 241) and all RP-only patients (n = 1005) were selected from a prospective database (2004–2015). The database contained HRQoL and prostate problem assessments up to 2 yr after last treatment. Outcome measurement and statistical analysis Mixed effects growth modelling adjusting for significant differences in patient characteristics and baseline HRQoL was used to analyze the association between: (1) “treatment” (RP-only vs SRT) and (2) “timing of SRT” with changes in HRQoL. Results and limitations SRT patients showed significantly (p < 0.05) poorer recovery from urinary, bowel, and erectile function after their last treatment (clinically meaningful difference for urinary and erectile function). Patients with a longer interval (≥ 7 mo) between RP and SRT reported significantly better sexual satisfaction after SRT (p = 0.02), and a better urinary function recovery (p = 0.03). Limitations of the study include the nonrandom design and the variability in timing of HRQoL measurements. Conclusions Up to 2 yr after treatment, SRT patients reported poorer HRQoL in several HRQoL domains compared with RP-only patients, but not in overall HRQoL. Delaying the start of SRT after RP may limit the incidence and duration of urinary and sexual problems. Nevertheless, decisions regarding SRT timing should also be based on the potential benefits in disease recurrence. Patient summary Patients who receive radiotherapy after surgery may experience poorer urinary, bowel, and erectile function compared with patients who undergo surgery only. Although more research is needed, delaying radiotherapy seems to limit its impact on urinary and sexual functioning