On using oscillating time-dependent restraints in MD simulation

The use of time-dependent restraints in molecular simulation in order to generate a conformational ensemble for molecules that is in accordance with measured ensemble averages for particular observable quantities is investigated. Using a model system consisting of liquid butane and the cyclic peptide antamanide the reproduction of particular average (3)J-coupling constant values in a molecular dynamics simulation is analysed. It is shown that the multiple-valuedness and the sizeable gradients of the Karplus curve relating (3)J-coupling constants measured in NMR experiments to the corresponding torsional-angle values cause severe problems when trying to restrain a (3)J-coupling constant to a value close to the extrema of the Karplus curve. The introduction of a factor oscillating with time into the restraining penalty function alleviates this problem and enhances the restrained conformational sampling

Nematoden in verband met de vruchtbaarheid van de grond

Openbare les Landbouwhogeschool, Wageninge

Dental implant placement in alveolar cleft patients:a retrospective comparative study on clinical and aesthetic outcomes

The aim of this retrospective study was to assess the clinical and aesthetic outcomes, and patient satisfaction, following dental implant therapy in cleft patients. Implant survival, changes in marginal bone level, pocket probing depths, plaque and bleeding indices, aesthetics, and patient satisfaction were assessed in 17 alveolar cleft patients and 17 matched controls. At follow-up (mean 72.4 +/- 46.4 months), one implant had been lost in the cleft group. Mean marginal bone loss at follow-up was -0.4 +/- 0.4 mm in cleft patients and -0.2 +/- 0.4 mm in controls. Aesthetics of the peri-implant soft tissues (pink aesthetic score) were less favourable (P = 0.025) in cleft patients (5.0 +/- 1.9) than in controls (6.5 +/- 1.7), while peri-implant parameters were comparable in the two groups. Overall patient satisfaction was 8.6 +/- 0.9 in cleft patients and 8.9 +/- 1.1 in controls (P = 0.331). In cleft patients, no difference in aesthetics was observed between patients who received additional bone augmentation at 3 months prior to implant placement and those who did not (P = 0.092). Dental implant therapy in cleft patients is associated with high implant survival, minor marginal bone loss, healthy peri-implant soft tissues, and high patient satisfaction. Only the aesthetics of the soft tissues was worse in cleft patients compared to augmented non-cleft patients

Self-report versus care provider registration of healthcare utilization: impact on cost and cost-utility

OBJECTIVES: This study aims to compare the impact of two different sources of resource use, self-report versus care provider registrations, on cost and cost utility. METHODS: Data were gathered for a cost-effectiveness study performed alongside a 2-year randomized controlled trial evaluating the effect of an INTERdisciplinary COMmunity-based management program (INTERCOM) for patients with chronic obstructive pulmonary disease (COPD). The program was offered by physiotherapists, dieticians and respiratory nurses. During the 2-year period, patients reported all resource use in a cost booklet. In addition, data on hospital admissions and outpatient visits, visits to the physiotherapist, dietician or respiratory nurse, diet nutrition, and outpatient medication were obtained from administrative records. The cost per quality-adjusted life-year (QALY) was calculated in two ways, using data from the cost booklet or registrations. RESULTS: In total, 175 patients were included in the study. Agreement between self-report and registrations was almost perfect for hospitalizations (rho = 0.93) and physiotherapist visits (rho = 0.86), but above 0.55, moderate, for all other types of care. The total cost difference between the registrations and the cost booklet was 464 euros with the highest difference for hospitalizations 386 euro. Based on the cost booklet the cost difference between the treatment group and usual care was 2,444 euros (95 percent confidence interval [CI], -819 to 5,950), which resulted in a cost-utility of 29,100 euro/QALY. For the registrations, the results were 2,498 euros (95 percent CI, -88 to 6,084) and 29,390 euro/QALY, respectively. CONCLUSIONS: This study showed that the use of self-reported data or data from registrations effected within-group costs, but not between-group costs or the cost utility

Entrepreneurial women’s cognitive ambidexterity : career and cultural influences

CITATION: De Villiers Scheepers, M. J., Boshoff, C. & Oostenbrink, M. 2017. Entrepreneurial women’s cognitive ambidexterity : career and cultural influences. South African Journal of Business Management, 48(2):21-33, doi:10.4102/sajbm.v48i4.40.The original publication is available at https://sajbm.orgThe purpose of this study was to examine how women’s career stage and Ubuntu (collectivist) values relate to their cognitive ambidexterity when pursuing entrepreneurial initiatives in multicultural South Africa. In this study individual cognitive ambidexterity was operationalised as using effectual and causal logic. More than three hundred businesswomen from diverse backgrounds were surveyed. The results revealed that career stage, self-efficacy and Ubuntu collectivism are important in women’s ambidexterity. Mature, efficacious women in their late career stage draw on their diverse networks and use effectual affordable loss, flexibility and causation when pursuing entrepreneurial initiatives. In contrast, younger, early-career women are more likely to use pre-commitment to ensure support from stakeholders. Women with Ubuntu values use their relationship skills to draw on resources from their networks and use ambidexterity (effectual and causal logic) in their entrepreneurial endeavours. The findings suggest that entrepreneurial women who develop their cognitive ambidexterity and draw on both effectual and causal approaches when initiating entrepreneurial initiatives are more likely to experience successful outcomes. These mental approaches can be developed by means of awareness, training and mentoring. This study extends the literature on women’s entrepreneurial decision-making in a culturally diverse society, demonstrating the influence of cultural values and career stage on effectual and causal logic.https://sajbm.org/index.php/sajbm/article/view/40Publisher's versio

Health-related quality of life in preschool children in five health conditions

Objective: To test the responsiveness of the Infant/Toddler Quality of Life Questionnaire (ITQOL) to five health conditions. In addition, to evaluate the impact of the child's age and gender on the ITQOL domain scores. Methods: Observational study of 494 Dutch preschool-aged children with five clinical conditions and 410 healthy preschool children randomly sampled from the general population. The clinical conditions included neurofibromatosis type 1, wheezing illness, bronchiolitis, functional abdominal complaints, and burns. Health-related quality of life (HRQoL) was assessed by a mailed parent-completed ITQOL. Mean ITQOL scale scores for all conditions were compared with scores obtained from the reference sample. The effect of patient's age and gender on ITQOL scores was assessed using multi-variable regression analysis. Results: In all health conditions, substantially lower scores were found for several ITQOL scales. The conditions had a variable effect on the type of ITQOL domains and a different magnitude of effect. Scores for 'physical functioning', 'bodily pain', and 'general health perceptions' showed the greatest range. Parental impact scales were equally affected by all conditions. In addition to disease type, the child's age and gender had an impact on HRQoL. Conclusions: The five health conditions (each with a distinct clinical profile) affected the ITQOL scales differently. These results indicate that the ITQOL is sensitive to specific characteristics and symptom expression of the childhood health conditions investigated. This insight into the sensitivity of the ITQOL to health conditions with different symptom expression may help in the interpretation of HRQoL results in future applications