Weerstand en compliantie

Oratie uitgesproken door Prof.dr. P. Steendijk bij de aanvaarding van het ambt van hoogleraar in de Cardiovasculaire Fysiologie, in het bijzonder Onderzoek van Methoden en Vernieuwingen van het (bio)Medisch Onderwijs aan de Universiteit Leiden op vrijdag 20 oktober 2017Oratie uitgesproken door Prof.dr. P. Steendijk bij de aanvaarding van het ambt van hoogleraar in de Cardiovasculaire Fysiologie, in het bijzonder Onderzoek van Methoden en Vernieuwingen van het (bio)Medisch Onderwijs aan de Universiteit Leiden op vrijdag 20 oktober 2017LUMC / Geneeskunde Repositoriu

Modelling of heat transfer process in condensing unit with titanium alloy tubes

One of the most important units of heat transfer equipment of a nuclear power plant is the condenser. Currently, at the nuclear stations of concern “Rosenergoatom” work is actively underway to replace the tubes of copper containing alloys to various steels or titanium alloys. Also, active work is underway on modernization of heat-exchange equipment of operating units. It is necessary to make the modelling of the parameters of condenser, to ensure that after the upgrade, the unit will continue operating normally. For this purpose, was created the model of module of tube bundle of condenser unit of K-33160 with tubes of titanium alloy. The modelling process is based on the equation of heat balance. In this work were modelled condenser of NPP of K-33160 with WWER-1000 reactor and the tubes of a titanium alloy VT0-1. The calculation was carried out for three presented methods and the error was less than 2%

Making a lecture stick: the effect of spaced instruction on knowledge retention in medical education

IntroductionPoor knowledge retention is a persistent problem among medical students. This challenging issue may be addressed by optimizing frequently used instructional designs, such as lectures. Guided by neuroscientific literature, we designed a spaced learning lecture in which the educator repeats the to-be-learned information using short temporal intervals. We investigated if this modified instructional design could enhance students' retention.Materials and MethodsSecond-year medical students (n = 148) were randomly allocated to either the spaced lecture or the traditional lecture. The spaced lecture consisted of three 15-min instructional periods, separated by 5-min intervals. A short summary of the preceding information was provided after each interval. The traditional lecture encompassed the same information including the summary in the massed format, thus without the intervals. All students performed a baseline knowledge test 2 weeks prior to the lectures and students' knowledge retention was assessed 8 days after the lectures.ResultsThe average score on the retention test (alpha = 0.74) was not significantly different between the spaced lecture group (33.8% 13.6%) and the traditional lecture group (31.8% +/- 12.9%) after controlling for students' baseline-test performance (F(1,104) = 0.566, p = 0.458). Students' narrative comments showed that the spaced lecture format was well-received and subjectively benefitted their attention-span and cognitive engagement.Discussion and Conclusion We were unable to show increased knowledge retention after the spaced lecture compared with the traditional lecture. Based on these findings, we provide recommendations for further research. Ultimately, we aim for optimized spaced learning designs to facilitate learning in the medical curriculum and to help educate health professionals with a solid knowledge base.Immunogenetics and cellular immunology of bacterial infectious disease

An understanding of (mis)understanders: exploring the underlying mechanisms of concept learning using functional magnetic resonance imaging

Obtaining adequate understanding of scientific concepts is considered challenging due to learners' misconceptions about natural phenomena. Misconceptions may coexist with scientific knowledge in the brain. Therefore, misconceptions must be cognitively inhibited in order to select the scientific knowledge. There is, however, lack of substantial neuroscientific evidence supporting this hypothesis. In this study, we sought for this evidence by investigating medical students who solved a cardiovascular conceptual problem in a magnetic resonance imaging scanner. Brain activation was compared between understanders who had the scientific knowledge, and misunderstanders who held a misconception. No significant activation was found in brain areas related to cognitive inhibition in understanders compared with misunderstanders. Therefore, we could not confirm the idea that cognitive inhibition is involved in overcoming a misconception. Instead, we found that the putamen was significantly activated in misunderstanders compared with understanders, suggesting a role for episodic memory in learners holding a misconception.Medical Education Researc

The effect of peer modelling and discussing modelled feedback principles on medical students' feedback skills: a quasi-experimental study

Background Teaching is an important professional skill for physicians and providing feedback is an important part of teaching. Medical students can practice their feedback skills by giving each other peer feedback. Therefore, we developed a peer feedback training in which students observed a peer that modelled the use of good feedback principles. Students then elaborated on the modelled feedback principles through peer discussion. This combination of peer modelling and discussing the modelled feedback principles was expected to enhance emulation of the feedback principles compared to (1) only peer modelling and (2) discussing the feedback principles without previous modelling. Methods In a quasi-experimental study design, 141 medical students were assigned randomly to three training conditions: peer modelling plus discussion (MD), non-peer modelled example (NM) or peer modelling without discussion (M). Before and after the training, they commented on papers written by peers. These comments served as a pre- and a post-measure of peer feedback. The comments were coded into different functions and aspects of the peer feedback. Non-parametrical Kruskall-Wallis tests were used to check for pre- and post-measure between-group differences in the functions and aspects. Results Before the training, there were no significant between-group differences in feedback functions and aspects. After the training, the MD-condition gave significantly more positive peer feedback than the NM-condition. However, no other functions or aspects were significantly different between the three conditions, mainly because the within-group interquartile ranges were large. Conclusions The large interquartile ranges suggest that students differed substantially in the effort placed into giving peer feedback. Therefore, additional incentives may be needed to motivate students to give good feedback. Teachers could emphasise the utility value of peer feedback as an important professional skill and the importance of academic altruism and professional accountability in the peer feedback process. Such incentives may convince more students to put more effort into giving peer feedback.Medical Education Researc

Biventricular function in exercise during autonomic (thoracic epidural) block

Background Blockade of cardiac sympathetic fibers by thoracic epidural anesthesia (TEA) was previously shown to reduce right and left ventricular systolic function and effective pulmonary arterial elastance. At conditions of constant paced heart rate, cardiac output and systemic hemodynamics were unchanged. In this study, we further investigated the effect of cardiac sympathicolysis during physical stress and increased oxygen demand. Methods In a cross-over design, 12 patients scheduled to undergo thoracic surgery performed dynamic ergometric exercise tests with and without TEA. Hemodynamics were monitored and biventricular function was measured by transthoracic two-dimensional and M-mode echocardiography, pulsed wave Doppler and tissue Doppler imaging. Results TEA attenuated systolic RV function (TV SMODIFIER LETTER PRIME: - 21%, P < 0.001) and LV function (MV SMODIFIER LETTER PRIME: - 14%, P = 0.025), but biventricular diastolic function was not affected. HR (- 11%, P < 0.001), SVI (- 15%, P = 0.006), CI (- 21%, P < 0.001) and MAP (- 12%, P < 0.001) were decreased during TEA, but SVR was not affected. Exercise resulted in significant augmentation of systolic and diastolic biventricular function. During exercise HR, SVI, CI and MAP increased (respectively, + 86%, + 19%, + 124% and + 17%, all P < 0.001), whereas SVR decreased (- 49%, P < 0.001). No significant interactions between exercise and TEA were found, except for RPP (P = 0.024) and MV E DT (P = 0.035). Conclusion Cardiac sympathetic blockade by TEA reduced LV and RV systolic function but did not significantly blunt exercise-induced increases in LV and RV function. These data indicate that additional mechanisms besides those controlled by the cardiac sympathetic nervous system are involved in the regulation of cardiac function during dynamic exercise

Novel Approaches to Treat Experimental Pulmonary Arterial Hypertension: A Review

Background. Pulmonary arterial hypertension (PAH) is a life-threatening disease characterized by an increase in pulmonary artery pressure leading to right ventricular (RV) hypertrophy, RV failure, and ultimately death. Current treatments can improve symptoms and reduce severity of the hemodynamic disorder but gradual deterioration in their condition often necessitates a lung transplant. Methods and Results. In experimental models of PAH, particularly the model of monocrotaline-induced pulmonary hypertension, efficacious treatment options tested so far include a spectrum of pharmacologic agents with actions such as anti-mitogenic, proendothelial function, proangiogenic, antiinflammatory and antioxidative. Emerging trends in PAH treatment are gene and cell therapy and their combination, like (progenitor) cells enriched with eNOS or VEGF gene. More animal data should be collected to investigate optimal cell type, in vitro cell transduction, route of administration, and number of cells to inject. Several recently discovered and experimentally tested interventions bear potential for therapeutic purposes in humans or have been shown already to be effective in PAH patients leading to improved life expectation and better quality of life. Conclusion. Since many patients remain symptomatic despite therapy, we should encourage research in animal models of PAH and implement promising treatments in homogeneous groups of PAH patients

What were you thinking?: Medical students' metacognition and perceptions of self-regulated learning

PhenomenonAs a component of self-regulated learning, metacognition is gaining attention in the medical education research community. Metacognition, simply put, is thinking about one's thinking. Having a metacognitive habit of mind is essential for healthcare professionals. This study identified the metacognitive competencies of medical students as they completed a conceptual learning task, and provided insight into students' perceptions of self-regulated learning in their curriculum. Approach: Eleven third-year medical students from a Dutch University were purposively sampled to participate in this qualitative study. The study design included a think-aloud assignment followed by a semi-structured interview. During the assignment, participants were instructed to think aloud while solving questions about medical physiological concepts such as blood flow, pressure, and resistance. Think-aloud data were collected through audiotaping and used to identify participants' metacognitive competencies. The assignment also served as a prompt for an interview in which participants were questioned about metacognitive knowledge, monitoring, experiences, and perceptions of self-regulated learning in their curriculum. All data were transcribed verbatim and analyzed iteratively using a template analysis. Findings: Students differed in their use of metacognitive skills, with an overall focus on monitoring and, to a lesser extent, on planning and evaluation. Additionally, differences were found in students' metacognitive knowledge and metacognitive experiences. There was apparent use of inefficient, superficial predictive cues. Regarding perceptions of self-regulated learning skills, some students felt no need to develop such skills as they perceived medical education as an exercise in memorizing facts. Others emphasized the need for more insight into their actual level of knowledge and competence. Insights: Pre-clinical medical students require explicit teaching of metacognitive skills to facilitate self-regulated learning. Educators should aim to integrate metacognition in the everyday discourse of the classroom to foster an environment in which students discuss their own learning.Supplemental data for this article is available online at .Cardiolog

Biventricular function in exercise during autonomic (thoracic epidural) block

Background Blockade of cardiac sympathetic fibers by thoracic epidural anesthesia (TEA) was previously shown to reduce right and left ventricular systolic function and effective pulmonary arterial elastance. At conditions of constant paced heart rate, cardiac output and systemic hemodynamics were unchanged. In this study, we further investigated the effect of cardiac sympathicolysis during physical stress and increased oxygen demand.Methods In a cross-over design, 12 patients scheduled to undergo thoracic surgery performed dynamic ergometric exercise tests with and without TEA. Hemodynamics were monitored and biventricular function was measured by transthoracic two-dimensional and M-mode echocardiography, pulsed wave Doppler and tissue Doppler imaging.Results TEA attenuated systolic RV function (TV SMODIFIER LETTER PRIME: - 21%, P < 0.001) and LV function (MV SMODIFIER LETTER PRIME: - 14%, P = 0.025), but biventricular diastolic function was not affected. HR (- 11%, P < 0.001), SVI (- 15%, P = 0.006), CI (- 21%, P < 0.001) and MAP (- 12%, P < 0.001) were decreased during TEA, but SVR was not affected. Exercise resulted in significant augmentation of systolic and diastolic biventricular function. During exercise HR, SVI, CI and MAP increased (respectively, + 86%, + 19%, + 124% and + 17%, all P < 0.001), whereas SVR decreased (- 49%, P < 0.001). No significant interactions between exercise and TEA were found, except for RPP (P = 0.024) and MV E DT (P = 0.035).Conclusion Cardiac sympathetic blockade by TEA reduced LV and RV systolic function but did not significantly blunt exercise-induced increases in LV and RV function. These data indicate that additional mechanisms besides those controlled by the cardiac sympathetic nervous system are involved in the regulation of cardiac function during dynamic exercise.Perioperative Medicine: Efficacy, Safety and Outcome (Anesthesiology/Intensive Care

Evaluation of pulmonary arterial hypertension: invasive or noninvasive?

Vascular Biology and Interventio