58 results on '"Speetjens P"'
Search Results
2. Evaluation of response to neoadjuvant chemotherapy in osteosarcoma using dynamic contrast-enhanced MRI: development and external validation of a model
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Kalisvaart, Gijsbert M., Van Den Berghe, Thomas, Grootjans, Willem, Lejoly, Maryse, Huysse, Wouter C. J., Bovée, Judith V. M. G., Creytens, David, Gelderblom, Hans, Speetjens, Frank M., Lapeire, Lore, van de Sande, Michiel A. J., Sys, Gwen, de Geus-Oei, Lioe-Fee, Verstraete, Koenraad L., and Bloem, Johan L.
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- 2024
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3. Impact of the COVID-19 Lockdown on Gifted and Non-Gifted Primary School Students' Well-Being and Motivation from a Self-Determination Perspective
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Samsen-Bronsveld, H. Elise, Van der Ven, Sanne H. G., Speetjens, Paula P. A. M., and Bakx, Anouke W. E. A.
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This study examined the impact of the COVID-19-induced school lockdown on need satisfaction, well-being and motivation in both gifted and non-gifted primary school students in the Netherlands. A total of 312 parents (122 from gifted children) participated. The lockdown had mainly negative effects on students' need satisfaction, well-being and motivation. However, the impact of the lockdown was less negative for gifted students. There was also a levelling effect: Before the lockdown, gifted students had lower need satisfaction, well-being and motivation than their non-gifted peers, but these differences decreased during the lockdown due to (stronger) declines in the non-gifted. Changes in non-gifted students' well-being and motivation, because of the lockdown, were negatively mediated by autonomy and relatedness with classmates. Among the gifted, this was positively mediated by competence. Only before the lockdown, the effects of giftedness on well-being and motivation were mediated by autonomy and relatedness satisfaction.
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- 2023
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4. DOSAGE study: protocol for a phase III non-inferiority randomised trial investigating dose-reduced chemotherapy for advanced colorectal cancer in older patients
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Hans Gelderblom, Marta Fiocco, Simon P Mooijaart, Gerrit-Jan Liefers, Wilbert B van den Hout, Frank M Speetjens, Frederiek van den Bos, Leti van Bodegom-Vos, Marije Slingerland, Nienke A de Glas, Johanneke E A Portielje, Marissa Cloos-van Balen, Joosje C Baltussen, Trishika R R Binda, Arjan J Verschoor, Cynthia Holterhues, Danny Houtsma, Anouk Jochems, and Leontine E A M M Spierings
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Medicine - Abstract
Introduction Treating older adults with chemotherapy remains a challenge, given their under-representation in clinical trials and the lack of robust treatment guidelines for this population. Moreover, older patients, especially those with frailty, have an increased risk of developing chemotherapy-related toxicity, resulting in a decreased quality of life (QoL), increased hospitalisations and high healthcare costs. Phase II trials have suggested that upfront dose reduction of chemotherapy can reduce toxicity rates while maintaining efficacy, leading to fewer treatment discontinuations and an improved QoL. The DOSAGE aims to show that upfront dose-reduced chemotherapy in older patients with metastatic colorectal cancer is non-inferior to full-dose treatment in terms of progression-free survival (PFS), with adaption of the treatment plan (monotherapy or doublet chemotherapy) based on expected risk of treatment toxicity.Methods and analysis The DOSAGE study is an investigator-initiated phase III, open-label, non-inferiority, randomised controlled trial in patients aged≥70 years with metastatic colorectal cancer eligible for palliative chemotherapy. Based on toxicity risk, assessed using the Geriatric 8 (G8) tool, patients will be stratified to either doublet chemotherapy (fluoropyrimidine with oxaliplatin) or fluoropyrimidine monotherapy. Patients classified as low risk will be randomised between a fluoropyrimidine plus oxaliplatin in either full-dose or with an upfront dose reduction of 25%. Patients classified as high risk will be randomised between fluoropyrimidine monotherapy in either full-dose or with an upfront dose reduction. In the dose-reduced arm, dose escalation after two cycles is allowed. The primary outcome is PFS. Secondary endpoints include grade≥3 toxicity, QoL, physical functioning, number of treatment cycles, dose reductions, hospital admissions, overall survival, cumulative received dosage and cost-effectiveness. Considering a median PFS of 8 months and non-inferiority margin of 8 weeks, we shall include 587 patients. The study will be enrolled in 36 Dutch Hospitals, with enrolment scheduled to start in July 2024. This study will provide new evidence regarding the effect of dose-reduced chemotherapy on survival and treatment outcomes, as well as the use of the G8 to choose between doublet chemotherapy or monotherapy. Results will contribute to a more individualised approach in older patients with metastatic colorectal cancer, potentially leading to improved QoL while maintaining survival benefits.Ethics and dissemination This trial has received ethical approval by the ethical committee Leiden Den Haag Delft (P24.018) and will be approved by the Institutional Ethical Committee of the participating institutions. The results will be disseminated in peer-reviewed scientific journals.Trial registration number NCT06275958.
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- 2024
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5. A phase I trial of LXS196, a protein kinase C (PKC) inhibitor, for metastatic uveal melanoma
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Piperno-Neumann, S., Carlino, M. S., Boni, V., Loirat, D., Speetjens, F. M., Park, J. J., Calvo, E., Carvajal, R. D., Nyakas, M., Gonzalez-Maffe, J., Zhu, X., Shirley, M. D., Ramkumar, T., Fessehatsion, A., Burks, H. E., Yerramilli-Rao, P., and Kapiteijn, E.
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- 2023
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6. Combining Melphalan Percutaneous Hepatic Perfusion with Ipilimumab Plus Nivolumab in Advanced Uveal Melanoma: First Safety and Efficacy Data from the Phase Ib Part of the Chopin Trial
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Tong, T. M. L., Burgmans, M. C., Speetjens, F. M., van Erkel, A. R., van der Meer, R. W., van Rijswijk, C. S. P., Jonker-Bos, M. A., Roozen, C. F. M., Sporrel-Blokland, M., Lutjeboer, J., van Persijn van Meerten, E. L., Martini, C. H., Zoethout, R. W. M., Tijl, F. G. J., Blank, C. U., and Kapiteijn, E.
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- 2023
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7. High resolution mapping shows differences in soil carbon and nitrogen stocks in areas of varying landscape history in Canadian lowland tundra
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Julia Wagner, Victoria Martin, Niek J. Speetjens, Willeke A'Campo, Luca Durstewitz, Rachele Lodi, Michael Fritz, George Tanski, Jorien E. Vonk, Andreas Richter, Annett Bartsch, Hugues Lantuit, and Gustaf Hugelius
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Random forest ,Machine learning ,Soil organic carbon ,Tundra ,Permafrost ,Science - Abstract
Soil organic carbon (SOC) in Arctic coastal polygonal tundra is vulnerable to climate change, especially in soils with occurrence of large amounts of ground ice. Pan-arctic studies of mapping SOC exist, yet they fail to describe the high spatial variability of SOC storage in permafrost landscapes. An important factor is the landscape history which determines landform development and consequently the spatial variability of SOC. Our aim was to map SOC stocks, and which environmental variables that determine SOC, in two adjacent coastal areas along Canadian Beaufort Sea coast with different glacial history. We used the machine learning technique random forest and environmental variables to map the spatial distribution of SOC stocks down to 1 m depth at a spatial resolution of 2 m for depth increments of 0–5, 5–15, 15–30, 30–60 and 60–100 cm.The results show that the two study areas had large differences in SOC stocks in the depth 60–100 cm due to high amounts of ground ice in one of the study areas. There are also differences in variable importance of the explanatory variables between the two areas. The area low in ground ice content had with 66.6 kg C/m−2 more stored SOC than the area rich in ground ice content with 40.0 kg C/m−2. However, this SOC stock could be potentially more vulnerable to climate change if ground ice melts and the ground subsides. The average N stock of the area low in ground ice is 3.77 kg m−2 and of the area rich in ground ice is 3.83 kg m−2.These findings support that there is a strong correlation between ground ice and SOC, with less SOC in ice-rich layers on a small scale. In addition to small scale studies of SOC mapping, detailed maps of ground ice content and distribution are needed for a validation of large-scale quantifications of SOC stocks and transferability of models.
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- 2023
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8. The pan-Arctic catchment database (ARCADE)
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N. J. Speetjens, G. Hugelius, T. Gumbricht, H. Lantuit, W. R. Berghuijs, P. A. Pika, A. Poste, and J. E. Vonk
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Environmental sciences ,GE1-350 ,Geology ,QE1-996.5 - Abstract
The Arctic is rapidly changing. Outside the Arctic, large-sample catchment databases have transformed catchment science from focusing on local case studies to more systematic studies of watershed functioning. Here we present an integrated pan-ARctic CAtchments summary DatabasE (ARCADE) of > 40 000 catchments that drain into the Arctic Ocean and range in size from 1 to 3.1 × 106 km2. These watersheds, delineated at a 90 m resolution, are provided with 103 geospatial, environmental, climatic, and physiographic catchment properties. ARCADE is the first aggregated database of pan-Arctic river catchments that also includes numerous small watersheds at a high resolution. These small catchments are experiencing the greatest climatic warming while also storing large quantities of soil carbon in landscapes that are especially prone to degradation of permafrost (i.e., ice wedge polygon terrain) and associated hydrological regime shifts. ARCADE is a key step toward monitoring the pan-Arctic across scales and is publicly available: https://doi.org/10.34894/U9HSPV (Speetjens et al., 2022).
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- 2023
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9. Small watersheds may play a disproportionate role in arctic land-ocean fluxes
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J. E. Vonk, N. J. Speetjens, and A. E. Poste
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Science - Abstract
While over 99% of coastal arctic rivers drain small catchments, future projections of land-ocean fluxes are based on data from large rivers. We encourage inclusion of and increased focus on smaller catchments to support representative assessments of arctic ecosystem change.
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- 2023
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10. Case report: challenges in monitoring and treatment of anthracycline induced cardiotoxicity in young adults with osteosarcoma
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Julius C. Heemelaar, Jeroen Janson, Jerry Braun, Frank M. Speetjens, Michiel A. J. van de Sande, Juan D. V. Hugo, Daniela Q. C. M. Barge-Schaapveld, Saskia L. M. A. Beeres, Laurens F. Tops, Hans Gelderblom, and M. Louisa Antoni
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Osteosarcoma ,Doxorubicin ,Cardiotoxicity ,Heart failure ,Case report ,Left ventricular assist device ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Abstract Neo(adjuvant) systemic treatment regimens containing anthracyclines such as doxorubicin cause a significant risk of heart failure. These regimens are one of the corner stones of osteosarcoma treatment, and therefore several guidelines are in place to steer cardiotoxicity monitoring through baseline risk stratification and cardiac surveillance during and after completion of cancer therapy. Importantly, baseline risk stratification modules are dependent on age, prior cardiovascular disease and cardiovascular risk factors. Because the majority of osteosarcoma patients are below 30 years of age these criteria rarely apply and most patients are assigned to low or medium risk categories, whereas cardiovascular complications have profound impact on morbidity and mortality in this young population. Therefore, cardiac surveillance is very important in this group for timely detection of cardiotoxicity. Moreover, when severe cardiotoxicity that requires advanced heart failure treatment occurs, a cancer diagnosis has significant implications on treatment options, i.e. mechanical circulatory support and heart transplantation. These challenges are presented in this case of a patient without clinical risk factors admitted with cardiogenic shock requiring advanced heart failure treatment within 1 month after completion of doxorubicin containing chemotherapy for the treatment of high grade osteosarcoma.
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- 2022
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11. Predictive Parameters in Patients Undergoing Percutaneous Hepatic Perfusion with Melphalan for Unresectable Liver Metastases from Uveal Melanoma: A Retrospective Pooled Analysis
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Tong, T. M. L., Samim, M., Kapiteijn, E., Meijer, T. S., Speetjens, F. M., Brüning, R., Schroeder, T. H., El-Sanosy, S., Maschke, H., Wacker, F. K., Vogel, A., Dewald, C. L. A., Goeman, J. J., and Burgmans, M. C.
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- 2022
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12. Dissolved organic matter characterization in soils and streams in a small coastal low-Arctic catchment
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N. J. Speetjens, G. Tanski, V. Martin, J. Wagner, A. Richter, G. Hugelius, C. Boucher, R. Lodi, C. Knoblauch, B. P. Koch, U. Wünsch, H. Lantuit, and J. E. Vonk
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Ecology ,QH540-549.5 ,Life ,QH501-531 ,Geology ,QE1-996.5 - Abstract
Ongoing climate warming in the western Canadian Arctic is leading to thawing of permafrost soils and subsequent mobilization of its organic matter pool. Part of this mobilized terrestrial organic matter enters the aquatic system as dissolved organic matter (DOM) and is laterally transported from land to sea. Mobilized organic matter is an important source of nutrients for ecosystems, as it is available for microbial breakdown, and thus a source of greenhouse gases. We are beginning to understand spatial controls on the release of DOM as well as the quantities and fate of this material in large Arctic rivers. Yet, these processes remain systematically understudied in small, high-Arctic watersheds, despite the fact that these watersheds experience the strongest warming rates in comparison. Here, we sampled soil (active layer and permafrost) and water (porewater and stream water) from a small ice wedge polygon (IWP) catchment along the Yukon coast, Canada, during the summer of 2018. We assessed the organic carbon (OC) quantity (using dissolved (DOC) and particulate OC (POC) concentrations and soil OC content), quality (δ13C DOC, optical properties and source apportionment) and bioavailability (incubations; optical indices such as slope ratio, Sr; and humification index, HIX) along with stream water properties (temperature, T; pH; electrical conductivity, EC; and water isotopes). We classify and compare different landscape units and their soil horizons that differ in microtopography and hydrological connectivity, giving rise to differences in drainage capacity. Our results show that porewater DOC concentrations and yield reflect drainage patterns and waterlogged conditions in the watershed. DOC yield (in mg DOC g−1 soil OC) generally increases with depth but shows a large variability near the transition zone (around the permafrost table). Active-layer porewater DOC generally is more labile than permafrost DOC, due to various reasons (heterogeneity, presence of a paleo-active-layer and sampling strategies). Despite these differences, the very long transport times of porewater DOC indicate that substantial processing occurs in soils prior to release into streams. Within the stream, DOC strongly dominates over POC, illustrated by DOC/POC ratios around 50, yet storm events decrease that ratio to around 5. Source apportionment of stream DOC suggests a contribution of around 50 % from permafrost/deep-active-layer OC, which contrasts with patterns observed in large Arctic rivers (12 ± 8 %; Wild et al., 2019). Our 10 d monitoring period demonstrated temporal DOC patterns on multiple scales (i.e., diurnal patterns, storm events and longer-term trends), underlining the need for high-resolution long-term monitoring. First estimates of Black Creek annual DOC (8.2 ± 6.4 t DOC yr−1) and POC (0.21 ± 0.20 t yr−1) export allowed us to make a rough upscaling towards the entire Yukon Coastal Plain (34.51 ± 2.7 kt DOC yr−1 and 8.93 ± 8.5 kt POC yr−1). Rising Arctic temperatures, increases in runoff, soil organic matter (OM) leaching, permafrost thawing and primary production are likely to increase the net lateral OC flux. Consequently, altered lateral fluxes may have strong impacts on Arctic aquatic ecosystems and Arctic carbon cycling.
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- 2022
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13. Treatment results for patients with squamous-cell carcinoma of the anus, a single institution retrospective analysis
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Karen J. Neelis, Django M. Kip, Frank M. Speetjens, and Yvette M. van der Linden
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Anal carcinoma ,Retrospective ,Chemoradiotherapy ,Treatment results ,Medical physics. Medical radiology. Nuclear medicine ,R895-920 ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Abstract Background and purpose To gain insight into the treatment outcomes for anal cancer a retrospective analysis was performed with a special emphasis on trends in outcome and toxicities over time and on treatment of elderly patients. Materials and methods Medical records of 98 consecutive patients with squamous cell carcinoma of the anus of all stages treated with curative intent between 01-01-2009 and 31-12-2018 were analyzed with follow up until 31-12-2020. Standard tumor and pathological lymph node dose were 59.4 Gy (median 59.4 Gy, range 59.4–70 Gy) or 60 Gy (no deviation from intended dose), elective nodal regions were treated with 45 Gy (no deviations). Radiotherapy techniques in this period evolved from 3D-conformal to IMRT and VMAT. In 23 patients electron beams were used. Results Median age was 63 years (range 41–88), the majority of patients were female (60%). Twenty three patients were > 75 years old. The TNM stages were I, II, IIIA, and IIIB in 18%, 40%, 15% and 27%, 58% of patients had N0 status. Concurrent mitomycin C and 5-fluoruracil-based chemotherapy was given in 63 patients (64%). Five-year overall survival (OS), disease free survival (DFS), locoregional control (LRC) and colostomy free survival (CFS) were 71%, 80%, 82%, and 82% for the whole group. Results in patients > 75 years of age were not statistically different from those in younger patients. With the introduction of more conformal techniques DFS did not change and toxicities decreased. Conclusion Real word treatment outcomes per disease stage were in line with what is reported in literature. Older patients should also be offered treatment with curative intent.
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- 2022
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14. Combining Hepatic Percutaneous Perfusion with Ipilimumab plus Nivolumab in advanced uveal melanoma (CHOPIN): study protocol for a phase Ib/randomized phase II trial
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T. M. L. Tong, M. K. van der Kooij, F. M. Speetjens, A. R. van Erkel, R. W. van der Meer, J. Lutjeboer, E. L. van Persijn van Meerten, C. H. Martini, R. W. M. Zoethout, F. G. J. Tijl, C. U. Blank, M. C. Burgmans, and E. Kapiteijn
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Advanced uveal melanoma ,Percutaneous hepatic perfusion ,Immunotherapy ,Liver metastases ,Medicine (General) ,R5-920 - Abstract
Abstract Background While immune checkpoint inhibition (ICI) has revolutionized the treatment of metastatic cutaneous melanoma, no standard treatments are available for patients with metastatic uveal melanoma (UM). Several locoregional therapies are effective in the treatment of liver metastases, such as percutaneous hepatic perfusion with melphalan (M-PHP). The available literature suggests that treatment with ICI following locoregional treatment of liver UM metastases can result in clinical response. We hypothesize that combining M-PHP with ICI will lead to enhanced antigen presentation and increased immunomodulatory effect, improving control of both hepatic and extrahepatic disease. Methods Open-label, single-center, phase Ib/randomized phase II trial, evaluating the safety and efficacy of the combination of M-PHP with ipilimumab (anti-CTLA-4 antibody) and nivolumab (anti-PD-1 antibody) in patients with unresectable hepatic metastases of UM in first-line treatment, with or without the limited extrahepatic disease. The primary objective is to determine the safety, toxicity, and efficacy of the combination regimen, defined by maximum tolerated dose (MTD) and progression-free survival (PFS) at 1 year. Secondary objectives include overall survival (OS) and overall response rate (ORR). A maximum of 88 patients will be treated in phase I and phase II combined. Baseline characteristics will be described with descriptive statistics (t-test, chi-square test). To study the association between risk factors and toxicity, a logistic regression model will be applied. PFS and OS will be summarized using Kaplan-Meier curves. Discussion This is the first trial to evaluate this treatment combination by establishing the maximum tolerated dose and evaluating the efficacy of the combination treatment. M-PHP has shown to be a safe and effective treatment for UM patients with liver metastases and became the standard treatment option in our center. The combination of ICI with M-PHP is investigated in the currently described trial which might lead to a better treatment response both in and outside the liver. Trial Registration This trial was registered in the US National Library of Medicine with identifier NCT04283890 . Registered as per February 2020 - Retrospectively registered. EudraCT registration number: 2018-004248-49. Local MREC registration number: NL60508.058.19.
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- 2022
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15. Combining Hepatic Percutaneous Perfusion with Ipilimumab plus Nivolumab in advanced uveal melanoma (CHOPIN): study protocol for a phase Ib/randomized phase II trial
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Tong, T. M. L., van der Kooij, M. K., Speetjens, F. M., van Erkel, A. R., van der Meer, R. W., Lutjeboer, J., van Persijn van Meerten, E. L., Martini, C. H., Zoethout, R. W. M., Tijl, F. G. J., Blank, C. U., Burgmans, M. C., and Kapiteijn, E.
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- 2022
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16. Treatment results for patients with squamous-cell carcinoma of the anus, a single institution retrospective analysis
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Neelis, Karen J., Kip, Django M., Speetjens, Frank M., and van der Linden, Yvette M.
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- 2022
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17. Probabilistic planning for ligament-balanced TKA—Identification of critical ligament properties
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Laura Bartsoen, Matthias G. R. Faes, Roel Wirix-Speetjens, David Moens, Ilse Jonkers, and Jos Vander Sloten
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total knee arthroplasty ,probabilistic planning ,ligament balancing ,musculoskeletal knee model ,ligament properties ,surgical precision ,Biotechnology ,TP248.13-248.65 - Abstract
Total knee arthroplasty (TKA) failures are often attributed to unbalanced knee ligament loading. The current study aims to develop a probabilistic planning process to optimize implant component positioning that achieves a ligament-balanced TKA. This planning process accounts for both subject-specific uncertainty, in terms of ligament material properties and attachment sites, and surgical precision related to the TKA process typically used in clinical practice. The consequent uncertainty in the implant position parameters is quantified by means of a surrogate model in combination with a Monte Carlo simulation. The samples for the Monte Carlo simulation are generated through Bayesian parameter estimation on the native knee model in such a way that each sample is physiologically relevant. In this way, a subject-specific uncertainty is accounted for. A sensitivity analysis, using the delta-moment-independent sensitivity measure, is performed to identify the most critical ligament parameters. The designed process is capable of estimating the precision with which the targeted ligament-balanced TKA can be realized and converting this into a success probability. This study shows that without additional subject-specific information (e.g., knee kinematic measurements), a global success probability of only 12% is estimated. Furthermore, accurate measurement of reference strains and attachment sites critically improves the success probability of the pre-operative planning process. To allow more precise planning, more accurate identification of these ligament properties is required. This study underlines the relevance of investigating in vivo or intraoperative measurement techniques to minimize uncertainty in ligament-balanced pre-operative planning results, particularly prioritizing the measurement of ligament reference strains and attachment sites.
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- 2022
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18. Automated mitral valve assessment for transcatheter mitral valve replacement planning
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Patricia Lopes, Paul L. Van Herck, Joris F. Ooms, Nicolas M. Van Mieghem, Roel Wirix-Speetjens, Jan Sijbers, Jos Vander Sloten, and Johan Bosmans
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pre-interventional planning ,automated mitral valve assessment ,saddle- and D-shaped mitral annulus ,statistical shape model (SSM) ,transcatheter mitral valve replacement (TMVR) ,cardiac CT ,Biotechnology ,TP248.13-248.65 - Abstract
Transcatheter mitral valve replacement (TMVR) has emerged as a minimally invasive alternative for treating patients suffering from mitral valve disease. The number of TMVR procedures is expected to rise as devices currently in clinical trials obtain approval for commercialization. Automating the planning of such interventions becomes, therefore, more relevant in an attempt to decrease inter-subject discrepancies and time spent in patient assessment. This study evaluates the performance of an automated method for detection of anatomical landmarks and generation of relevant measurements for device selection and positioning. Cardiac CT scans of 70 patients were collected retrospectively. Fifty scans were used to generate a statistical shape model (SSM) of the left heart chambers at ten different timepoints, whereas the remaining 20 scans were used for validation of the automated method. The clinical measurements resulting from the anatomical landmarks generated automatically were compared against the measurements obtained through the manual indication of the corresponding landmarks by three observers, during systole and diastole. The automatically generated measurements were in close agreement with the user-driven analysis, with intraclass correlation coefficients (ICC) consistently lower for the saddle-shaped (ICCArea = 0.90, ICCPerimeter 2D = 0.95, ICCPerimeter 3D = 0.93, ICCAP-Diameter = 0.71, ICCML-Diameter = 0.90) compared to the D-shaped annulus (ICCArea = 0.94, ICCPerimeter 2D = 0.96, ICCPerimeter 3D = 0.96, ICCAP-Diameter = 0.95, ICCML-Diameter = 0.92). The larger differences observed for the saddle shape suggest that the main discrepancies occur in the aorto-mitral curtain. This is supported by the fact that statistically significant differences are observed between the two annulus configurations for area (p < 0.001), 3D perimeter (p = 0.009) and AP diameter (p < 0.001), whereas errors for 2D perimeter and ML diameter remained almost constant. The mitral valve center deviated in average 2.5 mm from the user-driven position, a value comparable to the inter-observer variability. The present study suggests that accurate mitral valve assessment can be achieved with a fully automated method, what could result in more consistent and shorter pre-interventional planning of TMVR procedures.
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- 2022
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19. Intradermal vaccination of HPV-16 E6 synthetic peptides conjugated to an optimized Toll-like receptor 2 ligand shows safety and potent T cell immunogenicity in patients with HPV-16 positive (pre-)malignant lesions
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Hans Gelderblom, Sjoerd H van der Burg, Ferry Ossendorp, Peggy J de Vos van Steenwijk, Mariette I E van Poelgeest, Inge Roozen, Willem-Jan Krebber, Cornelis J M Melief, Frank M Speetjens, Marij J P Welters, Nikki M Loof, Sanne Boekestijn, Catharina A H Janssen, Marije Slingerland, Gijs G Zom, A Rob P M Valentijn, Nico J Meeuwenoord, Gijs A van der Marel, and Dmitri V Filippov
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Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Background Amplivant is a molecularly optimized Toll-like receptor 2 ligand that can be covalently conjugated to tumor peptide antigens. In preclinical models, amplivant-adjuvanted synthetic long peptides (SLPs) strongly enhanced antigen presentation by dendritic cells, T cell priming and induction of effective antitumor responses. The current study is a first-in-human trial to investigate safety and immunogenicity of amplivant conjugated to human papillomavirus (HPV) 16-SLP.Methods A dose escalation phase I vaccination trial was performed in 25 patients treated for HPV16 positive (pre-)malignant lesions. Amplivant was conjugated to two SLPs derived from the two most immunodominant regions of the HPV16 E6 oncoprotein. The vaccine, containing a mix of these two conjugates in watery solution without any other formulation, was injected intradermally three times with a 3-week interval in four dose groups (1, 5, 20 or 50 µg per conjugated peptide). Safety data were collected during the study. Peptide-specific T cell immune responses were determined in blood samples taken before, during and after vaccination using complementary immunological assays.Results Toxicity after three amplivant-conjugated HPV16-SLP vaccinations was limited to grade 1 or 2, observed as predominantly mild skin inflammation at the vaccination site and sometimes mild flu-like symptoms. Adverse events varied from none in the lowest dose group to mild/moderate vaccine-related inflammation in all patients and flu-like symptoms in three out of seven patients in the highest dose group, after at least one injection. In the lowest dose group, vaccine-induced T cell responses were observed in the blood of three out of six vaccinated persons. In the highest dose group, all patients displayed a strong HPV16-specific T cell response after vaccination. These HPV16-specific T cell responses lasted until the end of the trial.Conclusions Amplivant-conjugated SLPs can safely be used as an intradermal therapeutic vaccine to induce robust HPV16-specific T cell immunity in patients previously treated for HPV16 positive (pre-) malignancies. Increased vaccine dose was associated with a higher number of mild adverse events and with stronger systemic T cell immunity.Trial registration numbers NCT02821494 and 2014-000658-12.
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- 2022
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20. Corrigendum: Artificial Intelligence Based Patient-Specific Preoperative Planning Algorithm for Total Knee Arthroplasty
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Adriaan Lambrechts, Roel Wirix-Speetjens, Frederik Maes, and Sabine Van Huffel
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total knee arthroplasty ,patient-specific ,preoperative planning ,machine learning ,orthopedic surgery ,artificial intelligence ,Mechanical engineering and machinery ,TJ1-1570 ,Electronic computers. Computer science ,QA75.5-76.95 - Published
- 2022
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21. Percutaneous Hepatic Perfusion with Melphalan in Patients with Unresectable Ocular Melanoma Metastases Confined to the Liver: A Prospective Phase II Study
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Meijer, T. Susanna, Burgmans, Mark C., de Leede, Eleonora M., de Geus-Oei, Lioe-Fee, Boekestijn, Bas, Handgraaf, Henricus J. M., Hilling, Denise E., Lutjeboer, Jacob, Vuijk, Jaap, Martini, Christian H., van Erkel, Arian R., van der Meer, Rutger W., Tijl, Fred G. J., Speetjens, Frank M., Kapiteijn, Ellen, and Vahrmeijer, Alexander L.
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- 2021
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22. Artificial Intelligence Based Patient-Specific Preoperative Planning Algorithm for Total Knee Arthroplasty
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Adriaan Lambrechts, Roel Wirix-Speetjens, Frederik Maes, and Sabine Van Huffel
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total knee arthroplasty ,patient-specific ,preoperative planning ,machine learning ,orthopedic surgery ,support vector machine ,Mechanical engineering and machinery ,TJ1-1570 ,Electronic computers. Computer science ,QA75.5-76.95 - Abstract
Previous studies have shown that the manufacturer’s default preoperative plans for total knee arthroplasty with patient-specific guides require frequent, time-consuming changes by the surgeon. Currently, no research has been done on predicting preoperative plans for orthopedic surgery using machine learning. Therefore, this study aims to evaluate whether artificial intelligence (AI) driven planning tools can create surgeon and patient-specific preoperative plans that require fewer changes by the surgeon. A dataset of 5409 preoperative plans, including the manufacturer’s default and the plans corrected by 39 surgeons, was collected. Features were extracted from the preoperative plans that describe the implant sizes, position, and orientation in a surgeon- and patient-specific manner. Based on these features, non-linear regression models were employed to predict the surgeon’s corrected preoperative plan. The average number of corrections a surgeon has to make to the preoperative plan generated using AI was reduced by 39.7% compared to the manufacturer’s default plan. The femoral and tibial implant size in the manufacturer’s plan was correct in 68.4% and 73.1% of the cases, respectively, while the AI-based plan was correct in 82.2% and 85.0% of the cases, respectively, compared to the surgeon approved plan. Our method successfully demonstrated the use of machine learning to create preoperative plans in a surgeon- and patient-specific manner for total knee arthroplasty.
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- 2022
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23. Preoperative Prediction of Optimal Femoral Implant Size by Regularized Regression on 3D Femoral Bone Shape
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Adriaan Lambrechts, Christophe Van Dijck, Roel Wirix-Speetjens, Jos Vander Sloten, Frederik Maes, and Sabine Van Huffel
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total knee arthroplasty ,templating ,machine learning ,group lasso ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Preoperative determination of implant size for total knee arthroplasty surgery has numerous clinical and logistical benefits. Currently, surgeons use X-ray-based templating to estimate implant size, but this method has low accuracy. Our study aims to improve accuracy by developing a machine learning approach that predicts the required implant size based on a 3D femoral bone mesh, the key factor in determining the correct implant size. A linear regression framework imposing group sparsity on the 3D bone mesh vertex coordinates was proposed based on a dataset of 446 MRI scans. The group sparse regression method was further regularized based on the connectivity of the bone mesh to enforce neighbouring vertices to have similar importance to the model. Our hypergraph regularized group lasso had an accuracy of 70.1% in predicting femoral implant size while the initial implant size prediction provided by the instrumentation manufacturer to the surgeon has an accuracy of 23.1%. Furthermore, our method was capable of predicting the implant size up to one size smaller or larger with an accuracy of 99.1%, thereby surpassing other state-of-the-art methods. The hypergraph regularized group lasso was able to obtain a significantly higher accuracy compared to the implant size prediction provided by the instrumentation manufacturer.
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- 2023
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24. Terrestrial Dissolved Organic Matter Mobilized From Eroding Permafrost Controls Microbial Community Composition and Growth in Arctic Coastal Zones
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Anders Dalhoff Bruhn, Colin A. Stedmon, Jérôme Comte, Atsushi Matsuoka, Niek Jesse Speetjens, George Tanski, Jorien E. Vonk, and Johanna Sjöstedt
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climate change ,terrestrial dissolved organic matter ,Arctic coastal zone ,marine microbial community ,chemostat ,glacial deposits ,Science - Abstract
Climate warming is accelerating erosion along permafrost-dominated Arctic coasts. This results in the additional supply of organic matter (OM) and nutrients into the coastal zone. In this study we investigate the impact of coastal erosion on the marine microbial community composition and growth rates in the coastal Beaufort Sea. Dissolved organic matter (DOM) derived from three representative glacial deposit types (fluvial, lacustrine, and moraine) along the Yukon coastal plain, Canada, were used as substrate to cultivate marine bacteria using a chemostat setup. Our results show that DOM composition (inferred from UV-Visible spectroscopy) and biodegradability (inferred from DOC concentration, bacterial production and respiration) significantly differ between the three glacial deposit types. DOM derived from fluvial and moraine types show clear terrestrial characteristics with low aromaticity (Sr: 0.63 ± 0.02 and SUVA254: 1.65 ± 0.06 L mg C−1 m−1 & Sr: 0.68 ± 0.01 and SUVA254: 1.17 ± 0.06 L mg C−1 m−1, respectively) compared to the lacustrine soil type (Sr: 0.71 ± 0.02 and SUVA254: 2.15 ± 0.05 L mg C−1 m−1). The difference in composition of DOM leads to the development of three different microbial communities. Whereas Alphaproteobacteria dominate in fluvial and lacustrine deposit types (67 and 87% relative abundance, respectively), Gammaproteobacteria is the most abundant class for moraine deposit type (88% relative abundance). Bacterial growth efficiency (BGE) is 66% for DOM from moraine deposit type, while 13 and 28% for DOM from fluvial and lacustrine deposit types, respectively. The three microbial communities therefore differ strongly in their net effect on DOM utilization depending on the eroded landscape type. The high BGE value for moraine-derived DOM is probably caused by a larger proportion of labile colorless DOM. These results indicate that the substrate controls marine microbial community composition and activities in coastal waters. This suggests that biogeochemical changes in the Arctic coastal zone will depend on the DOM character of adjacent deposit types, which determine the speed and extent of DOM mineralization and thereby carbon channeling into the microbial food web. We conclude that marine microbes strongly respond to the input of terrestrial DOM released by coastal erosion and that the landscape type differently influence marine microbes.
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- 2021
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25. The Influence of Personalised Sarcoma Care (PERSARC) Prediction Modelling on Clinical Decision Making in a Multidisciplinary Setting
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H. S. Femke Hagenmaier, Annelies G. K. van Beeck, Rick L. Haas, Veroniek M. van Praag, Leti van Bodegom-Vos, Jos A. van der Hage, Stijn Krol, Frank M. Speetjens, Arjen H. G. Cleven, Ana Navas, Herman M. Kroon, Rieneke G. Moeri-Schimmel, Nicolette A. C. Leyerzapf, and Michiel A. J. van de Sande
- Subjects
Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Background. With soft-tissue sarcoma of the extremity (ESTS) representing a heterogenous group of tumors, management decisions are often made in multidisciplinary team (MDT) meetings. To optimize outcome, nomograms are more commonly used to guide individualized treatment decision making. Purpose. To evaluate the influence of Personalised Sarcoma Care (PERSARC) on treatment decisions for patients with high-grade ESTS and the ability of the MDT to accurately predict overall survival (OS) and local recurrence (LR) rates. Methods. Two consecutive meetings were organised. During the first meeting, 36 cases were presented to the MDT. OS and LR rates without the use of PERSARC were estimated by consensus and preferred treatment was recorded for each case. During the second meeting, OS/LR rates calculated with PERSARC were presented to the MDT. Differences between estimated OS/LR rates and PERSARC OS/LR rates were calculated. Variations in preferred treatment protocols were noted. Results. The MDT underestimated OS when compared to PERSARC in 48.4% of cases. LR rates were overestimated in 41.9% of cases. With the use of PERSARC, the proposed treatment changed for 24 cases. Conclusion. PERSARC aids the MDT to optimize individualized predicted OS and LR rates, hereby guiding patient-centered care and shared decision making.
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- 2021
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26. Phase I/II study protocol to assess safety and efficacy of adoptive cell therapy with anti-PD-1 plus low-dose pegylated-interferon-alpha in patients with metastatic melanoma refractory to standard of care treatments: the ACTME trial
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Gerrit-Jan Liefers, Sjoerd H van der Burg, Monique K van der Kooij, Marten Visser, Linda de Bruin, Ellen Kapiteijn, Els M E Verdegaal, Caroline E van der Minne, Pauline M Meij, Inge C F M Roozen, Mare A Jonker, Shelley van den Bosch, and Frank M Speetjens
- Subjects
Medicine - Abstract
Introduction Treatment with anti-PD-1 immunotherapy does not lead to long-lasting clinical responses in approximately 60% of patients with metastatic melanoma. These refractory patients, however, can still respond to treatment with tumour infiltrating lymphocytes (TIL) and interferon-alpha (IFNa). A combination of TIL, pegylated-interferon-alpha (PEG-IFNa) and anti-PD-1 is expected to provide a safe, feasible and effective therapy for patients with metastatic melanoma, who are refractory to standard of care treatment options.Methods and analysis Patients are treated in two phases. In phase I, the safety of the combination TIL and anti-PD-1 is assessed (cohort 1) according to CTCAE 4.03 criteria. Subsequently, the safety of cotreatment with PEG-IFNa is tested in cohort 2. The efficacy will be evaluated in the second phase of the trial. Efficacy is evaluated according to RECIST 1.1 and immune-related response criteria. Clinical and immunological parameters will be evaluated for their relation with clinical responsiveness.Ethics and dissemination Ethical approval of the trial was obtained from the Central Committee on Research Involving Human Subjects in the Netherlands. The trial results will be shared with the scientific community at (inter)national conferences and by publication in a peer-reviewed journal.Trial registration number NCT03638375; Pre-results.
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- 2020
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27. Lagrangian Transport and Chaotic Advection in Two-Dimensional Anisotropic Systems
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Varghese, Stephen, Speetjens, Michel, and Trieling, Ruben
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- 2017
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28. Effectiveness of the Triple P Positive Parenting Program on Parenting: A Meta-Analysis
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de Graaf, Ireen, Speetjens, Paula, and Smit, Filip
- Abstract
Triple P is a parenting program intended to prevent and to provide treatment for severe behavioral, emotional, and developmental problems in children. The aim of this meta-analysis was to assess the effectiveness of Triple P Level 4 interventions on parenting styles and parental competency. Level 4 is an intensive training program of 8-10 sessions for parents of children with more severe behavioral difficulties. The results indicated that the Triple P Level 4 interventions reduced dysfunctional parenting styles in parents and also improved parental competency. These effects were maintained well through time and appear to support the widespread adoption and implementation of Triple P Level 4 interventions that is taking place in an increasing number of countries around the world.
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- 2008
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29. Effectiveness of the Triple P Positive Parenting Program on Behavioral Problems in Children: A Meta-Analysis
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de Graaf, Ireen, Speetjens, Paula, Smit, Filip, de Wolff, Marianne, and Tavecchio, Louis
- Abstract
The Triple P Positive Parenting Program is a multilevel parenting program to prevent and offer treatment for severe behavioral, emotional, and developmental problems in children. The aim of this meta-analysis is to assess the effectiveness of Triple P Level 4 interventions in the management of behavioral problems in children by pooling the evidence from relevant literature that included Level 4 Triple P interventions. Level 4 intervention is indicated if the child has multiple behavior problems in a variety of settings and there are clear deficits in parenting skills. Results indicate that Level 4 of Triple P interventions reduced disruptive behaviors in children. These improvements were maintained well over time, with further improvements in long-term follow-up. These effects support the widespread adoption and implementation of Triple P that is taking place in an increasing number of countries in quite diverse cultural contexts around the world. (Contains 3 tables.)
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- 2008
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30. Particle focusing by AC electroosmosis with additional axial flow
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Liu, Zhipeng, Frijns, Arjan J. H., Speetjens, Michel F. M., and van Steenhoven, Anton A.
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- 2015
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31. Validated numerical analysis of vortical structures in 3D AC electro-osmotic flows
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Liu, Zhipeng, Speetjens, Michel F. M., Frijns, Arjan J. H., and van Steenhoven, Anton A.
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- 2014
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32. Application of astigmatism μ-PTV to analyze the vortex structure of AC electroosmotic flows
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Liu, Zhipeng, Speetjens, Michel F. M., Frijns, Arjan J. H., and van Steenhoven, Anton A.
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- 2014
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33. FoxP3- and CD8-positive Infiltrating Immune Cells Together Determine Clinical Outcome in Colorectal Cancer
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Zeestraten, Eliane C. M., Van Hoesel, Anneke Q., Speetjens, Frank M., Menon, Anand G., Putter, Hein, van de Velde, Cornelis J. H., and Kuppen, Peter J. K.
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- 2013
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34. Nuclear Localization of CXCR4 Determines Prognosis for Colorectal Cancer Patients
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Speetjens, Frank M., Liefers, Gerrit Jan, Korbee, Cornelis J., Mesker, Wilma E., van de Velde, Cornelis J.H., van Vlierberghe, Ronald L., Morreau, Hans, Tollenaar, Rob A., and Kuppen, Peter J.K.
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- 2009
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35. Sialyl Lewis X Expression and Lymphatic Microvessel Density in Primary Tumors of Node-negative Colorectal Cancer Patients Predict Disease Recurrence
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Doekhie, Fania S., Morreau, Hans, de Bock, Geertruida H., Speetjens, Frank M., Dekker-Ensink, N. Geeske, Putter, Hein, van de Velde, Cornelis J. H., Tollenaar, Rob A. E. M., and Kuppen, Peter J. K.
- Published
- 2008
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36. Clinical impact of HLA class I expression in rectal cancer
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Speetjens, Frank M., de Bruin, Elza C., Morreau, Hans, Zeestraten, Eliane C. M., Putter, Hein, van Krieken, J. Han, van Buren, Maaike M., van Velzen, Monique, Dekker-Ensink, N. Geeske, van de Velde, Cornelis J. H., and Kuppen, Peter J. K.
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- 2008
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37. Overzicht van vijftien jaar jeugdzorgonderzoek: Programmeringsstudie jeugdzorg
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Speetjens, Paula
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- 2007
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38. Het fundament van Triple P: Theoretische onderbouwing en onderzoek
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Speetjens, Paula, de Graaf, Ireen, and Blokland, Geraldien
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- 2007
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39. Online Group Course for Parents With Mental Illness: Development and Pilot Study
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van der Zanden, Rianne AP, Speetjens, Paula AM, Arntz, Karlijn SE, and Onrust, Simone A
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Computer applications to medicine. Medical informatics ,R858-859.7 ,Public aspects of medicine ,RA1-1270 - Abstract
BackgroundChildren of parents with mental illness (COPMI) are at greater risk of developing mental disorders themselves. Since impaired parenting skills appear to be a crucial factor, we developed a facilitated 8-session preventative group course called KopOpOuders (Chin Up, Parents) delivered via the Internet to Dutch parents with psychiatric problems. The goal was to promote children’s well-being by strengthening children’s protective factors via their parents. To reach parents at an early stage of their parenting difficulties, the course is easily accessible online. The course is delivered in a secure chat room, and participation is anonymous. ObjectiveThis paper reports on (1) the design and method of this online group course and (2) the results of a pilot study that assessed parenting skills, parental sense of competence, child well-being, and course satisfaction. MethodThe pilot study had a pre/post design. Parenting skills were assessed using Laxness and Overreactivity subscales of the Parenting Scale (PS). Sense of parenting competence was measured with the Ouderlijke Opvattingen over Opvoeding (OOO) questionnaire, a Dutch scale assessing parental perceptions of parenting using the Feelings of Incompetence and Feelings of Competence subscales. Child well-being was assessed with the total problem score, Emotional Problems, and Hyperactivity subscales of the Strengths and Difficulties Questionnaire (SDQ). Paired samples t tests were performed, and Cohen’s d was used to determine effect sizes. Intention-to-treat analyses and analyses of completers only were both performed. Course satisfaction was evaluated using custom-designed questionnaires. ResultsThe sample comprised 48 parents with mental illness. The response rate was 100% (48/48) at pretest and 58% (28/48) at posttest. Significant improvements were found on PS Laxness and Overreactivity subscales (P < .01) and on the OOO Feelings of Incompetence and Competence subscales (P < .01) in analysis of completers only as well as by intention-to-treat analysis. Effects were moderate on the PS (d = .52 and d = .48) and were large and moderate on the OOO (d = 0.61 and d = 0.46). At pretest, 75% and 64% of PS scores were in the clinical range, which declined to 43% and 39% at posttest. No significant changes were found for child well-being. Scores for approximately two thirds of children were not in the clinical range at both pretest and posttest. The mean course satisfaction score was 7.8 on a 10-point scale. Of all participants, 20% (10/48) followed all the sessions. ConclusionThis online group course on parenting skills is innovative in the field of e-support and among interventions for mentally ill parents. The pilot results are promising, showing moderate to large effects for parenting skills and parental sense of competence. Test scores at baseline indicating parenting problems were largely in the clinical range, and baseline scores indicating problems among the children were in the nonclinical range, suggesting that parents were reached at an early stage. Course satisfaction was high. Future research should focus on cost effectiveness and course adherence.
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- 2010
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40. Gene therapy with Apoptin induces regression of xenografted human hepatomas
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van der Eb, Marjolijn M, Pietersen, Alexandra M, Speetjens, Frank M, Kuppen, Peter JK, van de Velde, Cornelis JH, Noteborn, Mathieu HM, and Hoeben, Rob C
- Published
- 2002
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41. Automated muscle elongation measurement during reverse shoulder arthroplasty planning.
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Pitocchi, Jonathan, Plessers, Katrien, Wirix-Speetjens, Roel, Debeer, Philippe, van Lenthe, G. Harry, Jonkers, Ilse, Pérez, Maria Angeles, and Vander Sloten, Jos
- Abstract
Adequate deltoid and rotator cuff elongation in reverse shoulder arthroplasty is crucial to maximize postoperative functional outcomes and to avoid complications. Measurements of deltoid and rotator cuff elongation during preoperative planning can support surgeons in selecting a suitable implant design and position. Therefore, this study presented and evaluated a fully automated method for measuring deltoid and rotator cuff elongation. Complete scapular and humeral models were extracted from computed tomography scans of 40 subjects. First, a statistical shape model of the complete humerus was created and evaluated to identify the muscle attachment points. Next, a muscle wrapping algorithm was developed to identify the muscle paths and to compute muscle lengths and elongations after reverse shoulder arthroplasty implantation. The accuracy of the muscle attachment points and the muscle elongation measurements was evaluated for the 40 subjects by use of both complete and artificially created partial humeral models. Additionally, the muscle elongation measurements were evaluated for a set of 50 arthritic shoulder joints. Finally, a sensitivity analysis was performed to evaluate the impact of implant positioning on deltoid and rotator cuff elongation. For the complete humeral models, all muscle attachment points were identified with a median error < 3.5 mm. For the partial humeral models, the errors on the deltoid attachment point largely increased. Furthermore, all muscle elongation measurements showed an error < 1 mm for 75% of the subjects for both the complete and partial humeral models. For the arthritic shoulder joints, the errors on the muscle elongation measurements were <2 mm for 75% of the subjects. Finally, the sensitivity analysis showed that muscle elongations were affected by implant positioning. This study presents an automated method for accurately measuring muscle elongations during preoperative planning of shoulder arthroplasty. The results show that the accuracy in measuring muscle elongations is higher than the accuracy in indicating the muscle attachment points. Hence, muscle elongation measurements are insensitive to the observed errors on the muscle attachment points. Related to this finding, muscle elongations can be accurately measured for both a complete humeral model and a partial humeral model. Because the presented method also showed accurate results for arthritic shoulder joints, it can be used during preoperative shoulder arthroplasty planning, in which typically only the proximal humerus is present in the scan and in which bone arthropathy can be present. As the muscle elongations are sensitive to implant positioning, surgeons can use the muscle elongation measurements to refine their surgical plan. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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42. Automated quantification of glenoid bone defects using 3-dimensional measurements.
- Author
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Plessers, Katrien, Verhaegen, Filip, Van Dijck, Christophe, Wirix-Speetjens, Roel, Debeer, Philippe, Jonkers, Ilse, and Vander Sloten, Jos
- Abstract
Assessment of glenoid bone defects is important to select the optimal glenoid component design during shoulder arthroplasty planning and implantation. This study presents a fully automated method to describe glenoid bone loss using 3-dimensional measurements without the need for a healthy contralateral reference scapula. The native shape of the glenoid is reconstructed by fitting a statistical shape model (SSM) of the scapula. The total vault loss percentage, local vault loss percentages, defect depth, defect area percentage, and subluxation distance and region are computed based on a comparison of the reconstructed and eroded glenoids. The method is evaluated by comparing its results with a contralateral bone–based reconstruction approach in a data set of 34 scapula and humerus pairs with unilateral glenoid bone defects. The SSM-based defect measurements deviated from the contralateral bone–based measurements with mean absolute differences of 5.5% in the total vault loss percentage, 4.5% to 8.0% in the local vault loss percentages, 1.9 mm in the defect depth, 14.8% in the defect area percentage, and 1.6 mm in the subluxation distance. The SSM-based method was statistically equivalent to the contralateral bone–based method for all parameters except the defect area percentage. The presented method is able to automatically analyze glenoid bone defects using 3-dimensional measurements without the need for a healthy contralateral bone. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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43. A physical exercise program using music-supported video-based training in older adults in nursing homes suffering from dementia: a feasibility study.
- Author
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Spildooren, Joke, Speetjens, Ite, Abrahams, Johan, Feys, Peter, and Timmermans, Annick
- Abstract
Background: Motivation towards an exercise program is higher in a small group setting in comparison to individual therapy. Due to attentional problems, group exercises are difficult for people with Alzheimer disease (AD). This study evaluates the feasibility of a music-supported video-based group exercise program in older adults suffering from AD.Methods: Five participants with moderate AD were recruited from a nursing home. A progressive physical exercise program using a video-based training with musical accompaniment was performed and digitally recorded to investigate the adherence and performed accuracy of the exercises.Results: The overall participation during the exercises was 84.1%. The quality of the performance was for all exercises above the cut-off scores.Conclusion: A music-supported video-based group exercise program is feasible in persons with AD. The participants were motivated and the expectations towards the program increased over time. Music seemed an important factor for attention in participants with AD. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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44. Virtual reconstruction of glenoid bone defects using a statistical shape model.
- Author
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Plessers, Katrien, Vanden Berghe, Peter, Van Dijck, Christophe, Wirix-Speetjens, Roel, Debeer, Philippe, Jonkers, Ilse, and Vander Sloten, Jos
- Abstract
Background Description of the native shape of a glenoid helps surgeons to preoperatively plan the position of a shoulder implant. A statistical shape model (SSM) can be used to virtually reconstruct a glenoid bone defect and to predict the inclination, version, and center position of the native glenoid. An SSM-based reconstruction method has already been developed for acetabular bone reconstruction. The goal of this study was to evaluate the SSM-based method for the reconstruction of glenoid bone defects and the prediction of native anatomic parameters. Methods First, an SSM was created on the basis of 66 healthy scapulae. Then, artificial bone defects were created in all scapulae and reconstructed using the SSM-based reconstruction method. For each bone defect, the reconstructed surface was compared with the original surface. Furthermore, the inclination, version, and glenoid center point of the reconstructed surface were compared with the original parameters of each scapula. Results For small glenoid bone defects, the healthy surface of the glenoid was reconstructed with a root mean square error of 1.2 ± 0.4 mm. Inclination, version, and glenoid center point were predicted with an accuracy of 2.4° ± 2.1°, 2.9° ± 2.2°, and 1.8 ± 0.8 mm, respectively. Discussion and conclusion The SSM-based reconstruction method is able to accurately reconstruct the native glenoid surface and to predict the native anatomic parameters. Based on this outcome, statistical shape modeling can be considered a successful technique for use in the preoperative planning of shoulder arthroplasty. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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45. Self-Assembly and Post-Fabrication Functionalization of Microphase Separated Thin Films of a Reactive Azlactone-Containing Block Copolymer.
- Author
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Choi, Jonathan W., Carter, Matthew C. D., Wei Wei, Kanimozi, Catherine, Speetjens, Frank W., Mahanthappa, Mahesh K., Lynn, David M., and Gopalan, Padma
- Published
- 2016
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46. A Reactive Platform Approach for the Rapid Synthesis and Discovery of High χ/Low N Block Polymers.
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Carter, Matthew C. D., Jennings, James, Speetjens, Frank W., Lynn, David M., and Mahanthappa, Mahesh K.
- Published
- 2016
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47. Synthesis and Rheological Characterization of Poly(vinylacetate-b-vinyl alcohol-b-vinyl acetate) Triblock Copolymer Hydrogels.
- Author
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FrankW. Speetjens and Mahesh K. Mahanthappa
- Published
- 2015
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48. Evidence of Biaxial Order in the Cybotactic NematicPhase of Bent-Core Mesogens.
- Author
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Vita, Francesco, Tauscher, Tatum, Speetjens, Frank, Samulski, Edward T., Scharrer, Eric, and Francescangeli, Oriano
- Published
- 2014
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49. Steady-Stale Behavior of a Three-Dimensional Pool-Boiling System.
- Author
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Speetjens, Michel
- Subjects
ELECTRONICS ,COOLING ,NUCLEATE boiling ,TRANSITION temperature ,HEAT flux ,BIFURCATION theory ,INTERFACE circuits - Abstract
Pool-boiling serves as the physical model problem for electronics cooling by means of phase-change heat-transfer The key for optimal and reliable cooling capacity is better understanding of the conditions that determine the critical heat-flux (CHF). Exceeding CHF results in the transition from efficient nucleate-boiling to inefficient film-boiling. This transition is intimately related to the formation and stability of multiple (steady) states on the fluid-heater interface. To this end, the steady-state behavior of a three-dimensional pool-boiling system has been studied in terms of a representative mathematical model problem. This model problem involves only the temperature field within the heater and models the heat exchange with the boiling medium via a nonlinear boundary condition imposed on the fluid-heater interface. The steady-state behavior is investigated via a bifurcation analysis with a continuation algorithm based on the treatment of the model with the method of separation of variables and a Fourier-collocation method. This revealed that steady-state solutions with homogeneous interface temperatures may undergo bifurcations that result in multiple solutions with essentially heterogeneous interface temperatures. These heterogeneous states phenomenologically correspond with vapor patches ("dry spots") on the interface that characterize transition conditions. The findings on the model problem are consistent with laboratory experiments. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
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50. Time-dependent in silico modelling of orthognathic surgery to support the design of biodegradable bone plates.
- Author
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Vautrin, Antoine, Wesseling, Mariska, Wirix-Speetjens, Roel, and Gomez-Benito, Maria Jose
- Subjects
ORTHOGNATHIC surgery ,BIODEGRADABLE materials ,DESIGN exhibitions - Abstract
Orthognathic surgery is performed to realign the jaws of a patient through several osteotomies. The state-of-the-art bone plates used to maintain the bone fragments in place are made of titanium. The presence of these non-degradable plates can have unwanted side effects on the long term (e.g. higher infection risk) if they are not removed. Using a biodegradable material such as magnesium may be a possible solution to this problem. However, biodegradation leads to a decrease of mechanical strength, therefore a time-dependent computational approach can help to evaluate the performance of such plates. In the present work, a computational framework has been developed to include biodegradation and bone healing algorithms in a finite element model. It includes bone plates and the mandible, which are submitted to masticatory loads during the early healing period (two months following the surgery). Two different bone plate designs with different stiffnesses have been tested. The stiff design exhibited good mechanical stability, with maximum Von Mises stress being less than 40% of the yield strength throughout the simulation. The flexible design shows high stresses when the bone healing has not started in the fracture gaps, indicating possible failure of the plate. However, this design leads to a higher bone healing quality after two months, as more cartilage is formed due to higher strains exerted in fracture gaps. We therefore conclude that in silico modelling can support tuning of the design parameters to ensure mechanical stability and while promoting bone healing. [Display omitted] • Titanium plates are the gold standard in orthognathic surgery. • Side effect of titanium plate presents magnesium plates as an alternative. • Biodegradation of magnesium results in loss of mechanical properties over time. • Mixed in silico models of healing and degradation estimate time-dependent performance of plates. • Balance of degradation and healing is needed, a high stiffness plate can decrease healing quality. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
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