Abstract
We present a catalog of ∼100,000 periodic variable stars in Transiting Exoplanet Survey Satellite (TESS) full-frame image data among members of widely distributed moving groups identified ...with Gaia in the previous papers in the series. By combining the periods from our catalog attributable to rotation with previously derived rotation periods for benchmark open clusters, we develop an empirical gyrochronology relation of angular momentum evolution that is valid for stars with ages 10–1000 Myr. Excluding stars rotating faster than 2 days, which we find are predominantly binaries, we achieve a typical age precision of ≈0.2–0.3 dex and improving at older ages. Importantly, these empirical relations apply to not only FGK-type stars but also M-type stars, due to the angular momentum distribution being much smoother, simpler, continuous, and monotonic as compared to the rotation period distribution. As a result, we are also able to begin tracing in fine detail the nature of angular momentum loss in low-mass stars as functions of mass and age. We characterize the stellar variability amplitudes of the cool stars as functions of mass and age, which may correlate with the starspot covering fractions. We also identify pulsating variables among the hotter stars in the catalog, including
δ
Scuti,
γ
Dor, and slowly pulsating B-type variables. These data represent an important step forward in being able to estimate precise ages of FGK- and M-type stars in the field, starting as early as the pre-main-sequence phase of evolution.
Stellar rotation was proposed as a potential age diagnostic that is precise, simple, and applicable to a broad range of low-mass stars ( 1 ). Unfortunately, rotation period ( ) measurements of ...low-mass members of open clusters have undermined the idea that stars spin down with a common age dependence (i.e., ): K dwarfs appear to spin down more slowly than F and G dwarfs. Agüeros et al. interpreted data for the 1.4 Gyr-old cluster NGC 752 differently, proposing that after having converged onto a slow-rotating sequence in their first 600-700 Myr (by the age of Praesepe), K dwarf stall on that sequence for an extended period of time. We use data from Gaia DR2 to identify likely single-star members of the 1 Gyr-old cluster NGC 6811 with Kepler light curves. We measure for 171 members, more than doubling the sample relative to the existing catalog and extending the mass limit from to 0.6 . We then apply a gyrochronology formula calibrated with Praesepe and the Sun to 27 single G dwarfs in NGC 6811 to derive a precise gyrochronological age for the cluster of 1.04 0.07 Gyr. However, when our new low-mass rotators are included, NGC 6811's color- sequence deviates away from the naive 1 Gyr projection down to K (K5V, 0.7 ), where it clearly overlaps with Praesepe's. Combining these data with for other clusters, we conclude that the assumption that mass and age are separable dependencies is invalid. Furthermore, the cluster data show definitively that stars experience a temporary epoch of reduced braking efficiency where stall, and that the duration of this epoch lasts longer for lower-mass stars.
Reliable single unit neuron recordings from chronically implanted microelectrode arrays (MEAs) are essential tools in the field of neural engineering. However, following implantation, MEAs undergo a ...foreign body response that functionally isolates them from the brain and reduces the useful longevity of the array. We tested a novel electrodeposited platinum-iridium coating (EPIC) on penetrating recording MEAs to determine if it improved recording performance. We chronically implanted the arrays in rats and used electrophysiological and histological measurements to compare quantitatively the single unit recording performance of coated vs. uncoated electrodes over a 12-week period. The coated electrodes had substantially lower impedance at 1 kHz and reduced noise, increased signal-to-noise ratio, and increased number of discernible units per electrode as compared to uncoated electrodes. Post-mortem immunohistochemistry showed no significant differences in the immune response between coated and uncoated electrodes. Overall, the EPIC arrays provided superior recording performance than uncoated arrays, likely due to lower electrode impedance and reduced noise.
Summary
Background
Faecal calprotectin decreases during exclusive enteral nutrition in children with active Crohn's disease. It is unknown how faecal calprotectin changes during food re‐introduction ...and the influence of maintenance enteral nutrition.
Aims
To study changes to faecal calprotectin during exclusive enteral nutrition and at food reintroduction, and explore associations with maintenance enteral nutrition.
Methods
Children with Crohn's disease were followed during exclusive enteral nutrition and during food‐reintroduction. Faecal calprotectin was measured before, at 33 and 54 days of exclusive enteral nutrition, and at 17, 52 and 72 days after food‐reintroduction. Maintenance enteral nutrition use was recorded with estimated weight food diaries. Data are presented with medians and Q1:Q3.
Results
Sixty‐six patients started exclusive enteral nutrition and 41 (62%) achieved clinical remission (weighted paediatric Crohn's disease activity index <12.5). Baseline faecal calprotectin (mg/kg) decreased after 4 and 8 weeks of exclusive enteral nutrition (Start: 1433 Q1: 946, Q3: 1820 vs 33 days: 844 314, 1438 vs 54 days: 453 165, 1100; P < .001). Within 17 days of food reintroduction, faecal calprotectin increased to 953 Q1: 519, Q3: 1611 and by 52 days to 1094 660, 1625 (both P < .02). Fifteen of 41 (37%) children in remission used maintenance enteral nutrition (333 kcal or 18% of energy intake). At 17 days of food reintroduction, faecal calprotectin was lower in maintenance enteral nutrition users than non‐users (651 Q1: 271, Q3: 1781 vs 1238 749, 2102, P = .049) and correlated inversely with maintenance enteral nutrition volume (rho: −0.573, P = .041), kcals (rho: −0.584, P = .036) and % energy intake (rho: −0.649, P = .016). Maintenance enteral nutrition use was not associated with longer periods of remission (P = .7). Faecal calprotectin at the end of exclusive enteral nutrition did not predict length of remission.
Conclusions
The effect of exclusive enteral nutrition on faecal calprotectin is diminished early during food reintroduction. Maintenance enteral nutrition at ~18% of energy intake is associated with a lower faecal calprotectin at the early phase of food reintroduction but is ineffective in maintaining longer term remission.
Cigarette smoking is one of the major causes of coronary heart disease with a thirty percent mortality rate in the United States. Cigarette smoking acting on the central nervous system (CNS) to ...stimulate the sympathetic nervous system (SNS) through, which facilitates the secretion of serotonin (5-HT) and catecholamines to supraphysiological levels in blood. The enhanced levels of 5-HT and catecholamines in smokers' blood are associated with increases in G protein-coupled receptor signaling and serotonylation of small GTPases, which in turn lead to remodeling of cytoskeletal elements to enhance granule secretion and promote unique expression of sialylated
-glycan structures on smokers' platelets. These mechanisms enhance aggregation and adhesion of smokers' platelets relative to those of non-smokers. This review focuses on the known mechanisms by which 5-HT and SERT, in coordinated signaling with catecholamines, impacts cigarette smokers' platelet biology.
Recent measurements of rotation periods ( ) in the benchmark open clusters Praesepe (670 Myr), NGC 6811 (1 Gyr), and NGC 752 (1.4 Gyr) demonstrate that, after converging onto a tight sequence of ...slowly rotating stars in mass-period space, stars temporarily stop spinning down. These data also show that the duration of this epoch of stalled spin-down increases toward lower masses. To determine when stalled stars resume spinning down, we use data from the K2 mission and the Palomar Transient Factory to measure for 58 dwarf members of the 2.7 Gyr old cluster Ruprecht 147, 39 of which satisfy our criteria designed to remove short-period or near-equal-mass binaries. Combined with the Kepler data for the approximately coeval cluster NGC 6819 (30 stars with M > 0.85 ), our new measurements more than double the number of 2.5 Gyr benchmark rotators and extend this sample down to 0.55 . The slowly rotating sequence for this joint sample appears relatively flat (22 2 days) compared to sequences for younger clusters. This sequence also intersects the Kepler intermediate-period gap, demonstrating that this gap was not created by a lull in star formation. We calculate the time at which stars resume spinning down and find that 0.55 stars remain stalled for at least 1.3 Gyr. To accurately age-date low-mass stars in the field, gyrochronology formulae must be modified to account for this stalling timescale. Empirically tuning a core-envelope coupling model with open cluster data can account for most of the apparent stalling effect. However, alternative explanations, e.g., a temporary reduction in the magnetic braking torque, cannot yet be ruled out.
Biosimilar infliximab use in paediatric IBD Richmond, Lisa; Curtis, Lee; Garrick, Victoria ...
Archives of disease in childhood,
01/2018, Volume:
103, Issue:
1
Journal Article
Peer reviewed
Open access
Biosimilar infliximab became available in the UK in 2015. Paediatric experience to date on its use is limited. We prospectively evaluated the safety and efficacy of biosimilar infliximab (Remsima) in ...two paediatric gastroenterology networks in patients with inflammatory bowel disease.
Prospective clinical data were collected from laboratory reports, electronic patient records and case notes of 40 patients starting Remsima for the first time. Disease activity scores together with blood and stool biomarkers were used to assess response.
Our data set highlights that Remsima was associated with a significant clinical and biochemical improvement (p<0.01 or less for all parameters assessed) in Crohn's disease post induction. There were no significant safety issues noted. The total cost saving was £47 800, representing a 38% reduction from originator.
We found that biosimilar infliximab is as effective as originator infliximab and its use is associated with significant cost savings.
The anti-inflammatory effect of exclusive enteral nutrition on the gut of children with Crohn's disease is rapidly lost after food reintroduction. This study assessed disease dietary triggers ...following successful treatment with exclusive enteral nutrition.
Nutrient intake, dietary patterns and dietary biomarkers in faeces (gluten immunogenic peptides, undigestible starch, short chain fatty acids) were assessed in 14 children with Crohn's disease during early food reintroduction, following exclusive enteral nutrition. Groups above (Group A) and below (Group B) the median levels of faecal calprotectin after food reintroduction were assigned for comparative analysis.
Intakes of fibre, gluten-containing cereals and red and processed meat were significantly higher in Group A than Group B; (median Q1, Q3, g/day; Fibre: 12.1 11.2, 19.9 vs. 9.9 7.6, 12.1, p = 0.03; Red and processed meat: 151 66.7, 190 vs. 63.3 21.7, 67, p = 0.02; gluten-containing cereals: 289 207, 402 vs. 203 61, 232, p = 0.035). A diet consisting of cereals and meat products was predictive (92% accuracy) of higher faecal calprotectin levels after food reintroduction. In faeces, butyrate levels, expressed as absolute concentration and relative abundance, were higher in Group A than Group B by 28.4 µmol/g (p = 0.015) and 6.4% (p = 0.008), respectively. Levels of gluten immunogenic peptide and starch in faeces did not differ between the two groups.
This pilot study identified potential dietary triggers of gut inflammation in children with Crohn's disease after food reintroduction following treatment with exclusive enteral nutrition.
Clinical trials.gov registration number: NCT02341248; Clinical trials.gov URL: https://clinicaltrials.gov/ct2/show/NCT02341248 (retrospectively registered).
Same-electrode stimulation and recording with high spatial resolution, signal quality, and power efficiency is highly desirable in neuroscience and neural engineering. High spatial resolution and ...signal-to-noise ratio is necessary for obtaining unitary activities and delivering focal stimulations. Power efficiency is critical for battery-operated implantable neural interfaces. This study demonstrates the capability of recording single units as well as evoked potentials in response to a wide range of electrochemically safe stimulation pulses through high-resolution microelectrodes coated with co-deposition of Pt-Ir. It also compares signal-to-noise ratio, single unit activity, and power efficiencies between Pt-Ir coated and uncoated microelectrodes. To enable stimulation and recording with the same microelectrodes, microelectrode arrays were treated with electrodeposited platinum-iridium coating (EPIC) and tested in the CA1 cell body layer of rat hippocampi. The electrodes' ability to (1) inject a large range of electrochemically reversable stimulation pulses to the tissue, and (2) record evoked potentials and single unit activities were quantitively assessed over an acute time period. Compared to uncoated electrodes, EPIC electrodes recorded signals with higher signal-to-noise ratios (coated: 9.77 ± 1.95 dB; uncoated: 1.95 ± 0.40 dB) and generated lower voltages (coated: 100 mV; uncoated: 650 mV) for a given stimulus (5 μA). The improved performance corresponded to lower energy consumptions and electrochemically safe stimulation above 5 μA (>0.38 mC/cm
), which enabled elicitation of field excitatory post synaptic potentials and population spikes. Spontaneous single unit activities were also modulated by varying stimulation intensities and monitored through the same electrodes. This work represents an example of stimulation and recording single unit activities from the same microelectrode, which provides a powerful tool for monitoring and manipulating neural circuits at the single neuron level.
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