Repeated segregation and energy dissipation in an axially segregated granular bed

Discrete element simulations were used to study the segregation behaviour in a bed of bidisperse granules in a rotating drum. In the final state the large particles ended up in the upper part of the bed near the vertical walls. In order to arrive at this state, the system went through two cycles of structural changes, on top of which fast oscillations were observed between an axially segregated and a somewhat more mixed state. These oscillations were sustained by different angles of repose near the vertical walls and in the middle of the bed. Concomitantly with the structural changes, the system's energy dissipation went through two cycles after which it settled in the state requiring the least work of all traversed states, suggesting that the granular bed strives for minimal dissipation

Risk factors and mechanisms of stroke in young adults: The FUTURE study

Incidence of ischemic stroke and transient ischemic attack in young adults is rising. However, etiology remains unknown in 30–40% of these patients when current classification systems designed for the elderly are used. Our aim was to identify risk factors according to a pediatric approach, which might lead to both better identification of risk factors and provide a stepping stone for the understanding of disease mechanism, particularly in patients currently classified as “unknown etiology”. Risk factors of 656 young stroke patients (aged 18–50) of the FUTURE study were categorized according to the “International Pediatric Stroke Study” (IPSS), with stratification on gender, age and stroke of “unknown etiology”. Categorization of risk factors into ≥1 IPSS category was possible in 94% of young stroke patients. Chronic systemic conditions were more present in patients aged <35 compared to patients ≥35 (32.6% vs. 15.6%, p < 0.05). Among 226 patients classified as “stroke of unknown etiology” using TOAST, we found risk factors in 199 patients (88%) with the IPSS approach. We identified multiple risk factors linked to other mechanisms of stroke in the young than in the elderly. This can be a valuable starting point to develop an etiologic classification system specifically designed for young stroke patients.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: de Leeuw is supported by a clinical established investigator grant of the Dutch Heart Foundation (grant no. 2014 T060), and by a VIDI innovational grant from The Netherlands Organisation for Health Research and Development ZonMw (grant no. 016-126-351) and has also received research support from the “Dutch Epilepsy Fund” (grant no. 2010-18); Loes Rutten-Jacobs (LR-J) is supported by a British Heart Foundation Immediate Research Fellowship (FS/15/61/31626) (www.bhf.org.uk)

Risk factors and causes of ischemic stroke in 1322 young adults

Background:Identification of risk factors and causes of stroke is key to optimize treatment and prevent recurrence. Up to one-third of young patients with stroke have a cryptogenic stroke according to current classification systems (Trial of ORG 10172 in Acute Stroke Treatment [TOAST] and atherosclerosis, small vessel disease, cardiac pathology, other causes, dissection [ASCOD]). The aim was to identify risk factors and leads for (new) causes of cryptogenic ischemic stroke in young adults, using the pediatric classification system from the IPSS study (International Pediatric Stroke Study).Methods:This is a multicenter prospective cohort study conducted in 17 hospitals in the Netherlands, consisting of 1322 patients aged 18 to 49 years with first-ever, imaging confirmed, ischemic stroke between 2013 and 2021. The main outcome was distribution of risk factors according to IPSS classification in patients with cryptogenic and noncryptogenic stroke according to the TOAST and ASCOD classification.Results:The median age was 44.2 years, and 697 (52.7%) were men. Of these 1322 patients, 333 (25.2%) had a cryptogenic stroke according to the TOAST classification. Additional classification using the ASCOD criteria reduced the number patients with cryptogenic stroke from 333 to 260 (19.7%). When risk factors according to the IPSS were taken into account, the number of patients with no potential cause or risk factor for stroke reduced to 10 (0.8%).Conclusions:Among young adults aged 18 to 49 years with a cryptogenic ischemic stroke according to the TOAST classification, risk factors for stroke are highly prevalent. Using a pediatric classification system provides new leads for the possible causes in cryptogenic stroke, and could potentially lead to more tailored treatment for young individuals with stroke.Neurological Motor Disorder

Trigger factors for stroke in young adults: a case-crossover study

Background and ObjectivesCauses of stroke in young adults differ from those in the elderly individuals, and in a larger percentage,no cause can be determined. To gain more insight into the etiology of (cryptogenic) stroke in theyoung population, we investigated whether trigger factors, such as short-lasting exposure to toxins orinfection, may play a role.MethodsPatients aged 18–49 years with a first-ever ischemic stroke or intracerebral hemorrhage (ICH) in 17participating centers in the Netherlands completed a questionnaire about exposure to 9 potentialtrigger factors in hazard periods and on a regular yearly basis. A case-crossover design was used toassess relative risks (RRs) with 95% confidence intervals (95% CIs) by the Mantel-Haenszel case-crossover method, for any stroke (ischemic stroke and ICH combined) and for different etiologicsubgroups of ischemic stroke.ResultsOne thousand one hundred forty-six patients completed the questionnaire (1,043 patients withan ischemic stroke and 103 with an ICH, median age 44.0 years, 52.6% men). For any stroke, anincreased risk emerged within 1 hour of cola consumption (RR 2.0, 95% CI 1.5–2.8) and vigorousphysical exercise (RR 2.6, 95% CI 2.2–3.0), within 2 hours after sexual activity (RR 2.4, 95% CI1.6–3.5), within 4 hours after illicit drug use (RR 2.8, 95% CI 1.7–4.9), and within 24 hours afterfever or flu-like disease (RR 14.1, 95% CI 10.5–31.2; RR 13.9, 95% CI 8.9–21.9). Four triggerfactors increased the risk of other determined and cryptogenic ischemic stroke, 3 that of car-dioembolic stroke, 2 that of large vessel atherosclerosis and likely atherothrombotic strokecombined and stroke with multiple causes, and none that of stroke due to small vessel disease.DiscussionWe identified cola consumption, vigorous physical exercise, sexual activity, illicit drug use, fever, andflu-like disease as potential trigger factors for stroke in the young population and found differencesin the type and number of trigger factors associated with different etiologic subgroups of ischemicstroke. These findings might help in better understanding the pathophysiologic mechanisms of(cryptogenic) stroke in the young population.Paroxysmal Cerebral Disorder

The long-term risk of vascular disease and epilepsy after stroke in young adults

Contains fulltext : 165609.pdf (publisher's version ) (Open Access)Radboud University, 16 februari 2017Promotores : Leeuw, H.F. de, Klijn, C.J.M. Co-promotor : Dijk, E.J. va

A faulty compass: Why do some people choose situations that are not good for them?

Why do some people seem to be drawn to situations that are not good for them? While we all regularly end up in situations that we would have preferred to avoid, we tend to not choose situations or other people that are not good for us, and with time most of us get better at recognizing and avoiding these situations. However, it is a well-known clinical phenomenon that some people have a faulty compass when it comes to these situations, increasing the likelihood of repeated exposure to negative experiences and even trauma. In this paper, we reflect on the relationship between adverse experiences early in development and dysfunctional choices in adulthood, with the aim to reinvigorate interest in this clinically important phenomenon, which is in need of rigorous empirical study. Based on the literature and clinical observations, we distill four categories of hypotheses: people make dysfunctional choices 1) to process or master previous trauma, 2) out of habit and because of preferences for what is familiar, 3) to maintain a coherent view of themselves and the world, and 4) to avoid difficult emotions. We end with concrete questions that can help narrow down the heterogenous set of observations and explanations, providing a first step towards a better conceptualisation and systematic documentation of (factors contributing to) maladaptive situation selection. We dedicate this essay to Jack Rachman, who was a great inspirator for the field of experimental psychopathology with his essays highlighting phenomena that were overlooked and drawing attention to fresh ideas

A faulty compass: Why do some people choose situations that are not good for them?

Why do some people seem to be drawn to situations that are not good for them? While we all regularly end up in situations that we would have preferred to avoid, we tend to not choose situations or other people that are not good for us, and with time most of us get better at recognizing and avoiding these situations. However, it is a well-known clinical phenomenon that some people have a faulty compass when it comes to these situations, increasing the likelihood of repeated exposure to negative experiences and even trauma. In this paper, we reflect on the relationship between adverse experiences early in development and dysfunctional choices in adulthood, with the aim to reinvigorate interest in this clinically important phenomenon, which is in need of rigorous empirical study. Based on the literature and clinical observations, we distill four categories of hypotheses: people make dysfunctional choices 1) to process or master previous trauma, 2) out of habit and because of preferences for what is familiar, 3) to maintain a coherent view of themselves and the world, and 4) to avoid difficult emotions. We end with concrete questions that can help narrow down the heterogenous set of observations and explanations, providing a first step towards a better conceptualisation and systematic documentation of (factors contributing to) maladaptive situation selection. We dedicate this essay to Jack Rachman, who was a great inspirator for the field of experimental psychopathology with his essays highlighting phenomena that were overlooked and drawing attention to fresh ideas