... De onderzoekers wensen de leden van de stuurgroep te bedanken: Fred Deven (voorzitter), Lut V... more ... De onderzoekers wensen de leden van de stuurgroep te bedanken: Fred Deven (voorzitter), Lut Vanden Boer, Joost Bronselaer, Erik Dekker, Etienne Clevers, Mariella Maes, Jurn Verschraegen, Walter Brusselaers, Ritje Pauwels, Mie Moerenhout, Catherine Molleman en Prof. ...
Journal of Nuclear Medicine and Radiation Therapy, Aug 11, 2015
Objective: Nanotechnology has developed for both cancer diagnosis and therapy. The purpose of thi... more Objective: Nanotechnology has developed for both cancer diagnosis and therapy. The purpose of this study was to investigate the cytotoxic effect of magnetic nanoparticles as a carrier of 5-fluorouracil and x-ray on the level of proliferation capacity of DU145 prostate carcinoma cell line in monolayer model. Materials and Methods: Therefore, DU145 cells were cultured as monolayer and treated with different concentrations of 5-FU/ or nanoparticles as 5-FU carriers for 24 hours and 2Gy x-ray (6MV). After treatment with nanoparticles, the iron uptake of DU145 cells was monitored using atomic adsorption spectrometry (AAS). The cytotoxic effect of these nanoparticles on the cells was evaluated using the colony formation assay. Results: Our results indicated that iron content and therefore the cellular uptake of 5-FU loaded nanoparticles increased with the increase of nanoparticles concentrations. The viability of the cells is constant as along with the increase of the concentration of free 5-FU and 5-FU encapsulated in nanoparticles. Our finding showed that proliferation capacity of the cells decreased as along with the increase of the concentration of free 5-FU and PLGA coated iron oxide nanoparticles as a carrier of 5-fluorouracil in combination with x-ray. Our results point to the possibility that iron oxide nanoparticles as 5-fu carrier can affect more efficient that 5-Fu as enhanced radiation. Conclusion: According to this study, drug loaded nanoparticles could deliver 5-Fu more efficient into the cells. So, magnetic nanoparticles are effective drug delivery vehicles for 5-FU. PLGA coated iron oxide nanoparticles are biocompatible and this coating is an appropriate surface that can penetrate into the cells.
The Rasch model (Rasch, 1960) and the linear logistic test model (LLTM, Fischer, 1973, 1977) are ... more The Rasch model (Rasch, 1960) and the linear logistic test model (LLTM, Fischer, 1973, 1977) are two commonly used item response models. Both models are discussed in Chapter 2. The Rasch model assumes item indica tors as predictors, so that each item has a specific effect, the weight of the corresponding item indicator. The LLTM explains these effects in terms of item properties, or in other words item properties are used as item predic tors. Therefore, the LLTM may be considered an item explanatory model, in contrast with the Rasch model which is descriptive. The requirement that the values of the item properties be known in advance for every item is both a strength and a limitation of the LLTM. The strength is that the model supports a more parsimonious account of item effects, but the limitation is that the values specified for items on the properties imply additional model assumptions. In the current chapter, a model will be introduced with latent item properties: The values of these latent item properties do not have to be known apriori, but they may have unknown values that are estimated as model parameters. The model introduced in this chapter is called the model with internal restrietion on item difficulties (MIRID; Butter, De Boeck, & Verhelst, 1998). The MIRID was originally published by Butter et al. (1998), based on Butter (1994). In Butter et al. (1998), a conditional maximum likelihood formulation and estimation method was explained, and the results of a simulation study were presented. An application of the MIRID and an ex tension of the MIRID to the OPLM-MIRID (originally described by Butter, 1994) and the 2PL-MIRID can be found in Smits and De Boeck (2003). A comparison between two estimation methods for the MIRID and the OPLM-MIRID - a conditional maximum likelihood estimation (Smits, De Boeck, Verhelst, & Butter, 2001) and a marginal maximum likelihood es timation, implemented within PROC NLMIXED - can be found in Smits, De Boeck, and Verhelst (2003). The MIRID in its standard form will be explained in the first part of
Two issues regarding associations between negative emotions are addressed: (i) whether different ... more Two issues regarding associations between negative emotions are addressed: (i) whether different types of data imply similar associations and (ii) whether these associations can be accounted for by the overlap between emotion components. In study 1, issue (i) was examined using individual differences covariation, situational covariation, and judged emotion similarity data. Results showed that the associations implied by the different data types were highly similar. Regarding issue (ii), we argue theoretically that component overlap may account for the obtained correspondence. Study 2 empirically demonstrated that the different types of association were strongly related to overlap in appraisals and action tendencies. Similarity judgments, however, seemed to be primarily based on emotion co-occurrence, and were only to a smaller degree directly related to component overlap.
E. Goossens, L. Moens, I. Van Droogenbroeck, J. Verschueren, D. Smits, M. Van Opstal, F. Maes, E.... more E. Goossens, L. Moens, I. Van Droogenbroeck, J. Verschueren, D. Smits, M. Van Opstal, F. Maes, E. D'Haenens & J. Van Damme ... Promotoren coördinatieteam: J. Van Damme, P. Ghesquière, I. Nicaise, P. Onghena & P. Van Petegem Overige promotoren: B. De Fraine, ...
Personality and Individual Differences, Jul 1, 2007
A factor-analytic-based method to measure the inhibition of three verbally aggressive behaviours ... more A factor-analytic-based method to measure the inhibition of three verbally aggressive behaviours was investigated in two studies on self-report data. Inhibition was subdivided into two types: inhibition of the tendency to become verbally aggressive and inhibition of the verbally aggressive behaviour. In Study 1, it was investigated whether both kinds can be separated and measured by using a factor-analytic model. In Study 2, the approach was validated by relating both types of inhibition to broad and specific trait measures, either related to behaviour regulation or not. Inhibition of the tendency to become verbally aggressive was negatively related to Extraversion and Anger Out, and positively to hostility and a general inhibition measure. The inhibition of verbally aggressive behaviour was positively related to Agreeableness, Anger In (keeping anger inside) and anger out control (control of outward expression of anger), and negatively to Verbal Aggression and Anger Out.
... De onderzoekers wensen de leden van de stuurgroep te bedanken: Fred Deven (voorzitter), Lut V... more ... De onderzoekers wensen de leden van de stuurgroep te bedanken: Fred Deven (voorzitter), Lut Vanden Boer, Joost Bronselaer, Erik Dekker, Etienne Clevers, Mariella Maes, Jurn Verschraegen, Walter Brusselaers, Ritje Pauwels, Mie Moerenhout, Catherine Molleman en Prof. ...
Journal of Nuclear Medicine and Radiation Therapy, Aug 11, 2015
Objective: Nanotechnology has developed for both cancer diagnosis and therapy. The purpose of thi... more Objective: Nanotechnology has developed for both cancer diagnosis and therapy. The purpose of this study was to investigate the cytotoxic effect of magnetic nanoparticles as a carrier of 5-fluorouracil and x-ray on the level of proliferation capacity of DU145 prostate carcinoma cell line in monolayer model. Materials and Methods: Therefore, DU145 cells were cultured as monolayer and treated with different concentrations of 5-FU/ or nanoparticles as 5-FU carriers for 24 hours and 2Gy x-ray (6MV). After treatment with nanoparticles, the iron uptake of DU145 cells was monitored using atomic adsorption spectrometry (AAS). The cytotoxic effect of these nanoparticles on the cells was evaluated using the colony formation assay. Results: Our results indicated that iron content and therefore the cellular uptake of 5-FU loaded nanoparticles increased with the increase of nanoparticles concentrations. The viability of the cells is constant as along with the increase of the concentration of free 5-FU and 5-FU encapsulated in nanoparticles. Our finding showed that proliferation capacity of the cells decreased as along with the increase of the concentration of free 5-FU and PLGA coated iron oxide nanoparticles as a carrier of 5-fluorouracil in combination with x-ray. Our results point to the possibility that iron oxide nanoparticles as 5-fu carrier can affect more efficient that 5-Fu as enhanced radiation. Conclusion: According to this study, drug loaded nanoparticles could deliver 5-Fu more efficient into the cells. So, magnetic nanoparticles are effective drug delivery vehicles for 5-FU. PLGA coated iron oxide nanoparticles are biocompatible and this coating is an appropriate surface that can penetrate into the cells.
The Rasch model (Rasch, 1960) and the linear logistic test model (LLTM, Fischer, 1973, 1977) are ... more The Rasch model (Rasch, 1960) and the linear logistic test model (LLTM, Fischer, 1973, 1977) are two commonly used item response models. Both models are discussed in Chapter 2. The Rasch model assumes item indica tors as predictors, so that each item has a specific effect, the weight of the corresponding item indicator. The LLTM explains these effects in terms of item properties, or in other words item properties are used as item predic tors. Therefore, the LLTM may be considered an item explanatory model, in contrast with the Rasch model which is descriptive. The requirement that the values of the item properties be known in advance for every item is both a strength and a limitation of the LLTM. The strength is that the model supports a more parsimonious account of item effects, but the limitation is that the values specified for items on the properties imply additional model assumptions. In the current chapter, a model will be introduced with latent item properties: The values of these latent item properties do not have to be known apriori, but they may have unknown values that are estimated as model parameters. The model introduced in this chapter is called the model with internal restrietion on item difficulties (MIRID; Butter, De Boeck, & Verhelst, 1998). The MIRID was originally published by Butter et al. (1998), based on Butter (1994). In Butter et al. (1998), a conditional maximum likelihood formulation and estimation method was explained, and the results of a simulation study were presented. An application of the MIRID and an ex tension of the MIRID to the OPLM-MIRID (originally described by Butter, 1994) and the 2PL-MIRID can be found in Smits and De Boeck (2003). A comparison between two estimation methods for the MIRID and the OPLM-MIRID - a conditional maximum likelihood estimation (Smits, De Boeck, Verhelst, & Butter, 2001) and a marginal maximum likelihood es timation, implemented within PROC NLMIXED - can be found in Smits, De Boeck, and Verhelst (2003). The MIRID in its standard form will be explained in the first part of
Two issues regarding associations between negative emotions are addressed: (i) whether different ... more Two issues regarding associations between negative emotions are addressed: (i) whether different types of data imply similar associations and (ii) whether these associations can be accounted for by the overlap between emotion components. In study 1, issue (i) was examined using individual differences covariation, situational covariation, and judged emotion similarity data. Results showed that the associations implied by the different data types were highly similar. Regarding issue (ii), we argue theoretically that component overlap may account for the obtained correspondence. Study 2 empirically demonstrated that the different types of association were strongly related to overlap in appraisals and action tendencies. Similarity judgments, however, seemed to be primarily based on emotion co-occurrence, and were only to a smaller degree directly related to component overlap.
E. Goossens, L. Moens, I. Van Droogenbroeck, J. Verschueren, D. Smits, M. Van Opstal, F. Maes, E.... more E. Goossens, L. Moens, I. Van Droogenbroeck, J. Verschueren, D. Smits, M. Van Opstal, F. Maes, E. D'Haenens & J. Van Damme ... Promotoren coördinatieteam: J. Van Damme, P. Ghesquière, I. Nicaise, P. Onghena & P. Van Petegem Overige promotoren: B. De Fraine, ...
Personality and Individual Differences, Jul 1, 2007
A factor-analytic-based method to measure the inhibition of three verbally aggressive behaviours ... more A factor-analytic-based method to measure the inhibition of three verbally aggressive behaviours was investigated in two studies on self-report data. Inhibition was subdivided into two types: inhibition of the tendency to become verbally aggressive and inhibition of the verbally aggressive behaviour. In Study 1, it was investigated whether both kinds can be separated and measured by using a factor-analytic model. In Study 2, the approach was validated by relating both types of inhibition to broad and specific trait measures, either related to behaviour regulation or not. Inhibition of the tendency to become verbally aggressive was negatively related to Extraversion and Anger Out, and positively to hostility and a general inhibition measure. The inhibition of verbally aggressive behaviour was positively related to Agreeableness, Anger In (keeping anger inside) and anger out control (control of outward expression of anger), and negatively to Verbal Aggression and Anger Out.
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Papers by Dirk Smits