Results from a synthetic model of the ITER XRCS-Core diagnostic based on high-fidelity x-ray ray tracing.

A high-fidelity synthetic diagnostic has been developed for the ITER core x-ray crystal spectrometer diagnostic based on x-ray ray tracing. This synthetic diagnostic has been used to model expected performance of the diagnostic, to aid in diagnostic design, and to develop engineering tolerances. The synthetic model is based on x-ray ray tracing using the recently developed xicsrt ray tracing code and includes a fully three-dimensional representation of the diagnostic based on the computer aided design. The modeled components are: plasma geometry and emission profiles, highly oriented pyrolytic graphite pre-reflectors, spherically bent crystals, and pixelated x-ray detectors. Plasma emission profiles have been calculated for Xe44+, Xe47+, and Xe51+, based on an ITER operational scenario available through the Integrated Modelling & Analysis Suite database, and modeled within the ray tracing code as a volumetric x-ray source; the shape of the plasma source is determined by equilibrium geometry and an appropriate wavelength distribution to match the expected ion temperature profile. All individual components of the x-ray optical system have been modeled with high-fidelity producing a synthetic detector image that is expected to closely match what will be seen in the final as-built system. Particular care is taken to maintain preservation of photon statistics throughout the ray tracing allowing for quantitative estimates of diagnostic performance.

Measurement performance assessment for the ITER CXRS Edge diagnostic system.

Measurement performance assessment has been carried out for the latest design of the ITER Charge Exchange Recombination Spectroscopy (CXRS) Edge diagnostic system. Several plasma scenarios, covering all expected baseline operation regimes for ITER, were used. Various impurity (He, Be, C, and Ne) concentrations for the system whole spatial range (0.5 < r/a < 1.0) were considered. Statistical errors for the measurements of low-Z impurity temperature, density, and rotation velocity were calculated. Other non-statistical error sources were reviewed, including the presence of wall reflections, effects on the active charge-exchange line shape, calibration, and positioning uncertainties. Minimal impurity concentrations, allowing measurements with required accuracy, were obtained. It was shown that the CXRS Edge system will be able to measure primary plasma parameters with required accuracy, space, and time resolution.

Efficacy, safety, and user experience of DIY or open-source artificial pancreas systems: a systematic review.

The do-it-yourself artificial pancreas system (DIYAPS) is a patient-driven initiative with the potential to revolutionise diabetes management, automating insulin delivery with existing pumps and CGM combined with open-source algorithms. Given the considerable interest in this topic within the diabetes community, we have conducted a systematic review of DIYAPS efficacy, safety, and user experience. Following recognised procedures and reporting standards, we identified 10 eligible publications of 730 participants within the peer-reviewed literature. Overall, studies reported improvements in time in range, HbA1c (glycated haemoglobin), reduced hypoglycaemia, and improved quality of life with DIYAPS use. While results were positive, the identified studies were small, and the majority were observational and at high risk of bias. Further research including well-designed randomised trials comparing DIYAPS with appropriate comparators is recommended.

Exploring parental perspectives after commencement of flash glucose monitoring for type 1 diabetes in adolescents and young adults not meeting glycaemic targets: a qualitative study.

AIMS: To explore parental perspectives after flash glucose monitoring commencement in adolescents and young adults with type 1 diabetes who were not meeting glycaemic targets. METHODS: Twelve semi-structured interviews were conducted among parents of adolescents and young adults between the ages of 14 and 20 years (inclusive) with type 1 diabetes and not meeting glycaemic targets [HbA1c 81-130 mmol/mol (9.6-14.0%)] participating in a randomized controlled trial. Interviews were transcribed, then thematic analysis was performed to identify themes regarding parental experiences. RESULTS: Four key themes were found: flash glucose monitoring improved parental emotional well-being; flash glucose monitoring reduced diabetes-specific conflict within families; flash glucose monitoring facilitated the parental role in diabetes management; and sensor-related challenges, particularly sensors falling off, interfered with using flash glucose monitoring for diabetes management. The cost of self-funded sensors was the only barrier to continuing flash glucose monitoring that parents reported. CONCLUSIONS: This study provides new insights into the potential benefits and challenges of flash glucose monitoring use, drawn from the perspective of parents of adolescents and young adults not meeting glycaemic targets. As parents are often key partners in obtaining or purchasing this technology, these findings can be used to further inform parental expectations of this technology.

The ups and downs of low-carbohydrate diets in the management of Type 1 diabetes: a review of clinical outcomes.

Dietary management has been a mainstay of care in Type 1 diabetes since before the discovery of insulin when severe carbohydrate restriction was advocated. The use of insulin facilitated re-introduction of carbohydrate into the diet. Current management guidelines focus on a healthy and varied diet with consideration of glycaemic load, protein and fat. As a result of frustration with glycaemic outcomes, low-carbohydrate diets have seen a resurgence in popularity. To date, low-carbohydrate diets have not been well studied in the management of Type 1 diabetes. Studies looking at glycaemic outcomes from low-carbohydrate diets have largely been cross-sectional, without validated dietary data and with a lack of control groups. The participants have been highly motivated self-selected individuals who follow intensive insulin management practices, including frequent blood glucose monitoring and additional insulin corrections with tight glycaemic targets. These confounders limit the ability to determine the extent of the impact of dietary carbohydrate restriction on glycaemic outcomes. Carbohydrate-containing foods including grains, fruit and milk are important sources of nutrients. Hence, low-carbohydrate diets require attention to vitamin and energy intake to avoid micronutrient deficiencies and growth issues. Adherence to restricted diets is challenging and can have an impact on social normalcy. In individuals with Type 1 diabetes, adverse health risks such as diabetic ketoacidosis, hypoglycaemia, dyslipidaemia and glycogen depletion remain clinical concerns. In the present paper, we review studies published to date and provide clinical recommendations for ongoing monitoring and support for individuals who choose to adopt a low-carbohydrate diet. Strategies to optimize postprandial glycaemia without carbohydrate restriction are presented.

A photoelastic-modulator-based motional Stark effect polarimeter for ITER that is insensitive to polarized broadband background reflections.

A motional Stark effect polarimeter insensitive to polarized broadband light is proposed. Partially polarized background light is anticipated to be a significant source of systematic error for the ITER polarimeter. The proposed polarimeter is based on the standard dual photoelastic modulator approach, but with the introduction of a birefringent delay plate, it generates a sinusoidal spectral filter instead of the usual narrowband filter. The period of the filter is chosen to match the spacing of the orthogonally polarized Stark effect components, thereby increasing the effective signal level, but resulting in the destructive interference of the broadband polarized light. The theoretical response of the system to an ITER like spectrum is calculated and the broadband polarization tolerance is verified experimentally.

Fluoxetine suppresses calcium signaling in human T lymphocytes through depletion of intracellular calcium stores.

Selective serotonin reuptake inhibitors, such as fluoxetine, have recently been shown to exert anti-inflammatory and immunosuppressive effects. Although the effects on cytokine secretion, proliferation and viability of T lymphocytes have been extensively characterized, little is known about the mechanism behind these effects. It is well known that Ca(2+) signaling is an important step in the signaling transduction pathway following T cell receptor activation. Therefore, we investigated if fluoxetine interferes with Ca(2+) signaling in Jurkat T lymphocytes. Fluoxetine was found to suppress Ca(2+) signaling in response to T cell receptor activation. Moreover, fluoxetine was found to deplete intracellular Ca(2+) stores, thereby leaving less Ca(2+) available for release upon IP3- and ryanodine-receptor activation. The Ca(2+)-modifying effects of fluoxetine are not related to its capability to block the serotonin transporter, as even a large excess of 5HT did not abolish the effects. In conclusion, these data show that fluoxetine decreases IP3- and ryanodine-receptor mediated Ca(2+) release in Jurkat T lymphocytes, an effect likely to be at the basis of the observed immunosuppression.

Instrumentation for a multichord motional Stark effect diagnostic in KSTAR.

The motional Stark effect (MSE) diagnostic is used to measure the radial magnetic pitch angle profile in neutral beam heated plasmas. This information is used to calculate the safety factor, q, with magnetic equilibrium reconstruction codes such as EFIT. The MSE diagnostic is important during active shaping of the q profile to optimize confinement and stability, and it has become a key diagnostic in high performance tokamaks. A multichord photo-elastic modulator (PEM) based MSE system is being developed for a real-time plasma current profile control in Korea Superconducting Tokamak Advanced Research (KSTAR). The PEM-based approach is a standard method that measures the polarization direction of a single Stark line with narrow tunable bandpass filters. A tangential view of the heating beam provides good spatial resolution of 1-3 cm, which provides an opportunity to install 25 spatial channels spanning the major radius from 1.74 m to 2.84 m. Application of real-time control is a long-term technical goal after commissioning the diagnostic in KSTAR, which is expected in 2015. In this paper, we describe the design of this newly-constructed multichord MSE diagnostic in KSTAR.

Inhibiting connexin channels protects against cryopreservation-induced cell death in human blood vessels.

OBJECTIVES: Cryopreserved blood vessels are being increasingly employed in vascular reconstruction procedures but freezing/thawing is associated with significant cell death that may lead to graft failure. Vascular cells express connexin proteins that form gap junction channels and hemichannels. Gap junction channels directly connect the cytoplasm of adjacent cells and may facilitate the passage of cell death messengers leading to bystander cell death. Two hemichannels form a gap junction channel but these channels are also present as free non-connected hemichannels. Hemichannels are normally closed but may open under stressful conditions and thereby promote cell death. We here investigated whether blocking gap junctions and hemichannels could prevent cell death after cryopreservation. MATERIALS AND METHODS: Inclusion of Gap27, a connexin channel inhibitory peptide, during cryopreservation and thawing of human saphenous veins and femoral arteries was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assays and histological examination. RESULTS: We report that Gap27 significantly reduces cell death in human femoral arteries and saphenous veins when present during cryopreservation/thawing. In particular, smooth muscle cell death was reduced by 73% in arteries and 71% in veins, while endothelial cell death was reduced by 32% in arteries and 51% in veins. CONCLUSIONS: We conclude that inhibiting connexin channels during cryopreservation strongly promotes vascular cell viability.

Real-time MSE measurements for current profile control on KSTAR.

To step up from current day fusion experiments to power producing fusion reactors, it is necessary to control long pulse, burning plasmas. Stability and confinement properties of tokamak fusion reactors are determined by the current or q profile. In order to control the q profile, it is necessary to measure it in real-time. A real-time motional Stark effect diagnostic is being developed at Korean Superconducting Tokamak for Advanced Research for this purpose. This paper focuses on 3 topics important for real-time measurements: minimize the use of ad hoc parameters, minimize external influences and a robust and fast analysis algorithm. Specifically, we have looked into extracting the retardance of the photo-elastic modulators from the signal itself, minimizing the influence of overlapping beam spectra by optimizing the optical filter design and a multi-channel, multiharmonic phase locking algorithm.

Transfer of IP3 through gap junctions is critical, but not sufficient, for the spread of apoptosis.

Decades of research have indicated that gap junction channels contribute to the propagation of apoptosis between neighboring cells. Inositol 1,4,5-trisphosphate (IP3) has been proposed as the responsible molecule conveying the apoptotic message, although conclusive results are still missing. We investigated the role of IP3 in a model of gap junction-mediated spreading of cytochrome C-induced apoptosis. We used targeted loading of high-molecular-weight agents interfering with the IP3 signaling cascade in the apoptosis trigger zone and cell death communication zone of C6-glioma cells heterologously expressing connexin (Cx)43 or Cx26. Blocking IP3 receptors or stimulating IP3 degradation both diminished the propagation of apoptosis. Apoptosis spread was also reduced in cells expressing mutant Cx26, which forms gap junctions with an impaired IP3 permeability. However, IP3 by itself was not able to induce cell death, but only potentiated cell death propagation when the apoptosis trigger was applied. We conclude that IP3 is a key necessary messenger for communicating apoptotic cell death via gap junctions, but needs to team up with other factors to become a fully pro-apoptotic messenger.

The MAST motional Stark effect diagnostic.

A motional Stark effect (MSE) diagnostic is now installed and operating routinely on the MAST spherical tokamak, with 35 radial channels, spatial resolution of ∼2.5 cm, and time resolution of ∼1 ms at angular noise levels of ∼0.5°. Conventional (albeit very narrow) interference filters isolate π or σ polarized emission. Avalanche photodiode detectors with digital phase-sensitive detection measure the harmonics of a pair of photoelastic modulators operating at 20 and 23 kHz, and thus the polarization state. The π component is observed to be significantly stronger than σ, in reasonably good agreement with atomic physics calculations, and as a result, almost all channels are now operated on π. Trials with a wide filter that admits the entire Stark pattern (relying on the net polarization of the emission) have demonstrated performance almost as good as the conventional channels. MSE-constrained equilibrium reconstructions can readily be produced between pulses.

A comparison of two stomatal conductance models for ozone flux modelling using data from two Brassica species.

In this study we tested and compared a multiplicative stomatal model and a coupled semi-empirical stomatal-photosynthesis model in their ability to predict stomatal conductance to ozone (gst) using leaf-level data from oilseed rape (Brassica napus L.) and broccoli (Brassica oleracea L. var. italica Plenck). For oilseed rape, the multiplicative model and the coupled model were able to explain 72% and 73% of the observed gst variance, respectively. For broccoli, the models were able to explain 53% and 51% of the observed gst variance, respectively. These results support the coupled semi-empirical stomatal-photosynthesis model as a valid alternative to the multiplicative stomatal model for O3 flux modelling, in terms of predictive performance.

Connexin 43 hemichannels contribute to the propagation of apoptotic cell death in a rat C6 glioma cell model.

Gap junctions (GJs) have been demonstrated to communicate cell death signals from apoptotic to healthy cells, thereby spatially extending apoptosis. Before being incorporated into GJs, hemichannels (hemi-GJs) are normally closed but recent evidence suggests that they can be opened by various messengers and conditions, thereby forming a pore through which molecules can enter or leave the cell potentially leading to cell death. The aim of this study was to determine the contribution of GJs and hemichannels in the communication of apoptosis toward surrounding cells. We induced apoptosis in C6 glioma cells stably transfected with connexin (Cx)43, with cytochrome C (cytC) using in situ electroporation and found that healthy surrounding cells underwent apoptotic transformation. Work with various cell death markers, wild-type (WT) and Cx43-expressing cells, inhibitors of GJs and/or hemichannels, and Cx43 gene silencing showed that GJs contribute to the spread of apoptosis in a zone next to where apoptosis was triggered whereas hemichannels also promoted cell death beyond this area. Buffering cytoplasmic Ca(2+) changes inhibited the spread of apoptosis in both cases. We conclude that Cx43 hemichannels, in concert with their GJ counterparts, play a role in communicating cytC-induced apoptotic cell death messages.

Ab initio modeling of the motional Stark effect on MAST.

A multichord motional Stark effect (MSE) system has recently been built on the MAST tokamak. In MAST the pi and sigma lines of the MSE spectrum overlap due to the low magnetic field typical for present day spherical tokamaks. Also, the field curvature results in a large change in the pitch angle over the observation volume. The measured polarization angle does not relate to one local pitch angle but to an integration over all pitch angles in the observation volume. The velocity distribution of the neutral beam further complicates the measurement. To take into account volume effects and velocity distribution, an ab initio code was written that simulates the MSE spectrum on MAST. The code is modular and can easily be adjusted for other tokamaks. The code returns the intensity, polarized fraction, and polarization angle as a function of wavelength. Results of the code are presented, showing the effect on depolarization and wavelength dependence of the polarization angle. The code is used to optimize the design and calibration of the MSE diagnostic.

Dehydroascorbate and glucose are taken up into Arabidopsis thaliana cell cultures by two distinct mechanisms.

The possible involvement of glucose (Glc) carriers in the uptake of vitamin C in plant cells is still a matter of debate. For the first time, it was shown here that plant cells exclusively take up the oxidised dehydroascorbate (DHA) form. DHA uptake is not affected by 6-bromo-6-deoxy-ascorbate, an ascorbate (ASC) analogue, specifically demonstrating ASC uptake in animal cells. There is no competition between Glc and DHA uptake. Moreover, DHA and Glc carriers respond in the opposite manner to different inhibitors (cytochalasin B, phloretin and genistein). In conclusion, the plant plasma membrane DHA carrier is distinct from the plant Glc transporters.

Prevalence of 'Candidatus Helicobacter suis' in pigs of different ages.

Samples from the antrum and fundus of the stomachs of 457 pigs from 22 different herds were screened for the presence of 'Candidatus Helicobacter suis' by pcr, and samples from the antrum and/or fundus of 222 of the stomachs were tested for urease activity. The prevalence of the infection was very low before weaning, increased rapidly after weaning and reached 90 per cent in the adult boars and sows. The agreement between the results obtained with the pcr test and the urease test was very good for some age groups and sampling sites, but poor for other age groups and sampling sites.

Population dynamics of Excirolana armata (Isopoda: Cirolanidae) in Buenos Aires beaches, Argentina

Se estudió la dinámica y estructura poblacional de Excirolana armata en tres playas arenosas de la provincia de Buenos Aires (Argentina), de enero de 2004 a marzo de 2005. Se seleccionaron playas sometidas a distintos tipos de influencias antropogénicas. Los parámetros de la función de crecimiento de von Bertalanffy fueron determinados en cada playa. Esta especie mostró una notable fluctuación en su crecimiento, con tasas más bajas a fines de otoño y en invierno. La población de la playa con mayor grado de erosión antropogénica presentó los valores menores y más estables de densidad y biomasa, la más alta tasa de mortalidad y la menor longevidad. Las variaciones temporales del coeficiente alométrico de la relación longitud-peso seco indicaron un patron cíclico, con los menores valores en otoño-invierno y los mayores en verano. Las hembras predominaron en la población ebido a la corta duración de la temporada reproductiva. Las poblaciones argentinas y uruguayas tienen índices similares en el crecimiento, pero difieren en los valores de abundancia y densidad, probablemente como respuesta a variaciones en la orfodinámica de las playas y en las interacciones biológicas.

The population dynamics and structure of the cirolanid isopod Excirolana armata were studied from January 2004 through March 2005 in three sandy beaches of Buenos Aires Province (Argentina). Beaches with different types of anthropogenic influences were selected. The von Bertalanffy’s growth function parameters were determined for each population. There was a marked fluctuation in growth, with lowest rates in late autumn and winter. The isopod population of the beach exposed to the highest degree of anthropogenic erosion had thelowest and most stable values of abundance and biomass, the highest mortality rate and the shortest life span.Temporal fluctuations of the allometric coefficient of the length‑dry weight relationship indicated a cycling pattern,with lowest values during the autumn‑winter period and peak values in the summer. Females predominatedin the populations due to the short duration of the reproductive season. Argentine and Uruguayan populationsshowed similar growth performance indices, but differed in their abundance and biomass values, probably asa response to variations in beach morphodynamics and biological interactions.

Improved confinement due to open ergodic field lines imposed by the dynamic ergodic divertor in TEXTOR.

The ergodization of the magnetic field lines imposed by the dynamic ergodic diverter (DED) in TEXTOR can lead both to confinement improvement and to confinement deterioration. The cases of substantial improvement are in resonant ways related to particular conditions in which magnetic flux tubes starting at the X points of induced islands are connected with the wall. This opening process is connected with a characteristic modification of the heat deposition pattern at the divertor target plate and leads to a substantial increase and steepening of the core plasma density and pressure. The improvement is tentatively attributed to a modification of the electric potential in the plasma carried by the open field lines. The confinement improvement bases on a spontaneous density built up due to the application of the DED and is primarily a particle confinement improvement.