Time equals money?: A randomized controlled field experiment on the effects of four types of training vouchers on training participation

Organizations aiming to help their employees in fostering their human capital offer training, but not all employees participate. Some organizations therefore experiment with training vouchers that typically offer financial means for training to motivate training participation. However, the effectiveness of such vouchers remains suboptimal, arguably due to lack of clarity on- and variation in the mechanisms of such vouchers. The present paper uniquely employs Conservation of Resources theory to compare the effectiveness of four types of vouchers with different combinations of money and time as well as different (i.e. firm internal and external) governance on training participation. To this end, 230 employees in a large Dutch insurance company were randomly assigned to one of the four voucher types or a control group. For eleven months, training participation was monitored and a concurrent questionnaire measured several personal characteristics as potential covariates and moderators. We find that the voucher type that allows employees to freely choose between a training budget and training days most strongly encourages training participation. Vouchers that provide employees with either working days or a training budget did not improve training participation significantly compared to the control group. Moreover, moderation analyses suggested that the training participation of employees provided with non-flexible vouchers appears to depend more strongly on personal characteristics, and particularly components from the Reasoned Action Approach. These findings suggest that to encourage training participation organizations should best offer flexible vouchers that provide employees a free choice between money and working time to spend on training. Moreover, the findings demonstrate the applicability of Conservation of Resource theory to training vouchers and address the need for recognizing subjectivity within this theoretical framework

Sensitivity of Cancer Cells to Truncated Diphtheria Toxin

Background: Diphtheria toxin (DT) has been utilized as a prospective anti-cancer agent for the targeted delivery of cytotoxic therapy to otherwise untreatable neoplasia. DT is an extremely potent toxin for which the entry of a single molecule into a cell can be lethal. DT has been targeted to cancer cells by deleting the cell receptor-binding domain and combining the remaining catalytic portion with targeting proteins that selectively bind to the surface of cancer cells. It has been assumed that ‘‘receptorless’ ’ DT cannot bind to and kill cells. In the present study, we report that ‘‘receptorless’ ’ recombinant DT385 is in fact cytotoxic to a variety of cancer cell lines. Methods: In vitro cytotoxicity of DT385 was measured by cell proliferation, cell staining and apoptosis assays. For in vivo studies, the chick chorioallantoic membrane (CAM) system was used to evaluate the effect of DT385 on angiogenesis. The CAM and mouse model system was used to evaluate the effect of DT385 on HEp3 and Lewis lung carcinoma (LLC) tumor growth, respectively. Results: Of 18 human cancer cell lines tested, 15 were affected by DT385 with IC 50 ranging from 0.12–2.8 mM. Furthermore, high concentrations of DT385 failed to affect growth arrested cells. The cellular toxicity of DT385 was due to the inhibition of protein synthesis and induction of apoptosis. In vivo, DT385 diminished angiogenesis and decreased tumor growth in the CAM system, and inhibited the subcutaneous growth of LLC tumors in mice

Depletion of embryonic macrophages leads to a reduction in Angiogenesis in the Ex OVO chick Chorioallantoic membrane assay

Macrophages play an important but poorly understood role in angiogenesis. To investigate their role in vessel formation, relevant in vivo models are crucial. Although the chick chorioallantoic membrane (CAM) model has been frequently used as an angiogenesis assay, limited data are available on the involvement of chicken macrophages in this process. Here, we describe a method to deplete macrophages in the ex ovo chick CAM assay by injection of clodronate liposomes and show that this depletion directly affects vascularisation of collagen onplants. Chicken embryos were injected intravenously with either clodronate or phosphate-buffered saline (PBS) liposomes, followed by placement of collagen type I plugs on the CAM to quantify angiogenic ingrowth. Clodronate liposome injection led to a significant 3.4-fold reduction of macrophages compared with control embryos as measured by immunohistochemistry and flow cytometry. Furthermore, analysis of vessel ingrowth into the collagen plugs revealed a significantly lower angiogenic response in macrophage-depleted embryos compared with control embryos, indicating that chicken embryonic macrophages play an essential function in the development of blood vessels. These results demonstrate that the chick CAM assay provides a promising model to investigate the role of macrophages in angiogenesis

Real-Time Visualization and Quantitation of Vascular Permeability In Vivo: Implications for Drug Delivery

The leaky, heterogeneous vasculature of human tumors prevents the even distribution of systemic drugs within cancer tissues. However, techniques for studying vascular delivery systems in vivo often require complex mammalian models and time-consuming, surgical protocols. The developing chicken embryo is a well-established model for human cancer that is easily accessible for tumor imaging. To assess this model for the in vivo analysis of tumor permeability, human tumors were grown on the chorioallantoic membrane (CAM), a thin vascular membrane which overlays the growing chick embryo. The real-time movement of small fluorescent dextrans through the tumor vasculature and surrounding tissues were used to measure vascular leak within tumor xenografts. Dextran extravasation within tumor sites was selectively enhanced an interleukin-2 (IL-2) peptide fragment or vascular endothelial growth factor (VEGF). VEGF treatment increased vascular leak in the tumor core relative to surrounding normal tissue and increased doxorubicin uptake in human tumor xenografts. This new system easily visualizes vascular permeability changes in vivo and suggests that vascular permeability may be manipulated to improve chemotherapeutic targeting to tumors

Kinderen met gedragsproblemen en sport?

1.Special Heroes: sport en gedragsproblemenRemo Mombarg2. Live beelden: hoe gaat dat dan Arjen Pruim &amp; Andries Zijlstra 3. Werkvorm: Ter introductie: CAR-vaardighedenSimon Leistra: 30 minCasuïstiek aan de hand de stappen</p

Standard errors of two-level scalability coefficients

For the construction of tests and questionnaires that require multiple raters (e.g., a child behaviour checklist completed by both parents) a novel ordinal scaling technique is currently being further developed, called two‐level Mokken scale analysis. The technique uses within‐rater and between‐rater coefficients to assess the scalability of the test. These coefficients are generalizations of Mokken's scalability coefficients. In this paper we derived standard errors for the two‐level coefficients and for their ratios. The coefficients, the estimates, the estimated standard errors and the software implementation are discussed and illustrated using a real‐data example, and a small‐scale simulation study demonstrates the accuracy of the estimates