6 research outputs found
Overview of T and D-T results in JET with ITER-like wall
In 2021 JET exploited its unique capabilities to operate with T and D–T fuel with an ITER-like Be/W wall (JET-ILW). This second major JET D–T campaign (DTE2), after DTE1 in 1997, represented the culmination of a series of JET enhancements—new fusion diagnostics, new T injection capabilities, refurbishment of the T plant, increased auxiliary heating, in-vessel calibration of 14 MeV neutron yield monitors—as well as significant advances in plasma theory and modelling in the fusion community. DTE2 was complemented by a sequence of isotope physics campaigns encompassing operation in pure tritium at high T-NBI power. Carefully conducted for safe operation with tritium, the new T and D–T experiments used 1 kg of T (vs 100 g in DTE1), yielding the most fusion reactor relevant D–T plasmas to date and expanding our understanding of isotopes and D–T mixture physics. Furthermore, since the JET T and DTE2 campaigns occurred almost 25 years after the last major D–T tokamak experiment, it was also a strategic goal of the European fusion programme to refresh operational experience of a nuclear tokamak to prepare staff for ITER operation. The key physics results of the JET T and DTE2 experiments, carried out within the EUROfusion JET1 work package, are reported in this paper. Progress in the technological exploitation of JET D–T operations, development and validation of nuclear codes, neutronic tools and techniques for ITER operations carried out by EUROfusion (started within the Horizon 2020 Framework Programme and continuing under the Horizon Europe FP) are reported in (Litaudon et al Nucl. Fusion accepted), while JET experience on T and D–T operations is presented in (King et al Nucl. Fusion submitted)
Maturation of the Cardiac Autonomic Nervous System Activity in Children and Adolescents
Background
Despite the increasing interest in cardiac autonomic nervous activity, the normal development is not fully understood. The main aim was to determine the maturation of different cardiac sympathetic‐(SNS) and parasympathetic nervous system (PNS) activity parameters in healthy patients aged 0.5 to 20 years. A second aim was to determine potential sex differences.
Methods and Results
Five studies covering the 0.5‐ to 20‐year age range provided impedance‐ and electrocardiography recordings from which heart rate, different PNS‐parameters (eg, respiratory sinus arrhythmia) and an SNS‐parameter (pre‐ejection period) were collected. Age trends were computed in the mean values across 12 age‐bins and in the age‐specific variances. Age was associated with changes in mean and variance of all parameters. PNS‐activity followed a cubic trend, with an exponential increase from infancy, a plateau phase during middle childhood, followed by a decrease to adolescence. SNS‐activity showed a more linear trend, with a gradual decrease from infancy to adolescence. Boys had higher SNS‐activity at ages 11 to 15 years, while PNS‐activity was higher at 5 and 11 to 12 years with the plateau level reached earlier in girls. Interindividual variation was high at all ages. Variance was reasonably stable for SNS‐ and the log‐transformed PNS‐parameters.
Conclusions
Cardiac PNS‐ and SNS‐activity in childhood follows different maturational trajectories. Whereas PNS‐activity shows a cubic trend with a plateau phase during middle childhood, SNS‐activity shows a linear decrease from 0.5 to 20 years. Despite the large samples used, clinical use of the sex‐specific centile and percentile normative values is modest in view of the large individual differences, even within narrow age bands.National Institute of Diabetes and Digestive and Kidney Diseases; the Netherlands Organization for Scientific Research; National Initiative for Brain and Cognition Research; European Commission under the 7th Framework Health Program with Grant; The Netherlands Organization for Health Research and Development (ZonMw); The Dutch Heart Foundatio
Intranasal Application of Secretin, Similarly to Intracerebroventricular Administration, Influences the Motor Behavior of Mice Probably Through Specific Receptors.
Secretin and its receptors show wide distribution in the central
nervous system. It was demonstrated previously that intravenous
(i.v.) and intracerebroventricular (i.c.v.) application of
secretin influenced the behavior of rat, mouse, and human. In
our previous experiment, we used a special animal model,
Japanese waltzing mice (JWM). These animals run around without
stopping (the ambulation distance is very limited) and they do
not bother with their environment. The i.c.v. secretin
attenuated this hyperactive repetitive movement. In the present
work, the effect of i.c.v. and intranasal (i.n.) application of
secretin was compared. We have also looked for the presence of
secretin receptors in the brain structures related to motor
functions. Two micrograms of i.c.v. secretin improved the
horizontal movement of JWM, enhancing the ambulation distance.
It was nearly threefold higher in treated than in control
animals. The i.n. application of secretin to the left nostril
once or twice a day or once for 3 days more effectively
enhanced the ambulation distance than i.c.v. administration.
When secretin was given twice a day for 3 days it had no effect.
Secretin did not improve the explorative behavior (the rearing),
of JWM. With the use of in situ hybridization, we have found
very dense secretin receptor labeling in the cerebellum. In the
primary motor cortex and in the striatum, only a few labeled
cells were seen. It was supposed that secretin exerted its
effect through specific receptors, mainly present in the
cerebellum
Baseline autonomic nervous system activity in female children and adolescents with conduct disorder: Psychophysiological findings from the FemNAT-CD study
Purpose: Autonomic nervous system (ANS) functioning has been widely studied in relation to antisocial behavior, such as Conduct Disorder (CD). However, research in females is scarce and findings are inconsistent. This study investigated baseline ANS activity in CD children and adolescents and tested for sex differences. Furthermore, subgroups of CD were investigated: +/‐ Limited Prosocial Emotions (LPE), +/‐ comorbid internalizing disorders (INT). Methods: Baseline ANS activity was measured by Heart Rate (HR), Heart Rate Variability (HRV; parasympathetic activity), Pre-Ejection Period (PEP; sympathetic activity), and Respiration Rate (RR). 659 females (296 CD, 363 controls) and 351 males (187 CD, 164 controls), aged 9–18 years participated. Results: Baseline HR, HRV and PEP did not differ between CD subjects and controls in both sexes. RR was higher in CD participants than controls amongst females, but not males. LPE was unrelated to ANS activity, whereas females with CD + INT presented lower HRV. Conclusions: These results suggest that baseline ANS activity is not a robust indicator for CD. However, deviant ANS activity – especially parasympathetic activity - was observed in CD females with internalizing comorbidity. The psychophysiological abnormalities observed in this subgroup are indicative of emotion regulation problems. Accordingly, this subgroup may require specific interventions. © 201
Overview of T and D–T results in JET with ITER-like wall
In 2021 JET exploited its unique capabilities to operate with T and D–T fuel with an ITER-like Be/W wall (JET-ILW). This second major JET D–T campaign (DTE2), after DTE1 in 1997, represented the culmination of a series of JET enhancements—new fusion diagnostics, new T injection capabilities, refurbishment of the T plant, increased auxiliary heating, in-vessel calibration of 14 MeV neutron yield monitors—as well as significant advances in plasma theory and modelling in the fusion community. DTE2 was complemented by a sequence of isotope physics campaigns encompassing operation in pure tritium at high T-NBI power. Carefully conducted for safe operation with tritium, the new T and D–T experiments used 1 kg of T (vs 100 g in DTE1), yielding the most fusion reactor relevant D–T plasmas to date and expanding our understanding of isotopes and D–T mixture physics. Furthermore, since the JET T and DTE2 campaigns occurred almost 25 years after the last major D–T tokamak experiment, it was also a strategic goal of the European fusion programme to refresh operational experience of a nuclear tokamak to prepare staff for ITER operation. The key physics results of the JET T and DTE2 experiments, carried out within the EUROfusion JET1 work package, are reported in this paper. Progress in the technological exploitation of JET D–T operations, development and validation of nuclear codes, neutronic tools and techniques for ITER operations carried out by EUROfusion (started within the Horizon 2020 Framework Programme and continuing under the Horizon Europe FP) are reported in (Litaudon et al Nucl. Fusion accepted), while JET experience on T and D–T operations is presented in (King et al Nucl. Fusion submitted)