3,067 research outputs found
A cell autonomous role for the Notch ligand Delta-like 3 in αβ T- cell development
Notch signalling is critical to help direct T-cell lineage commitment in early T-cell progenitors and in the development of αβ T-cells. Epithelial and stromal cell populations in the thymus express the Notch DSL (Delta, Serrate and Lag2) ligands Delta-like 1 (Dll1), Delta-like 4 (Dll4), Jagged 1 and Jagged 2, and induce Notch signalling in thymocytes that express the Notch receptor. At present there is nothing known about the role of the Delta-like 3 (Dll3) ligand in the immune system. Here we describe a novel cell autonomous role for Dll3 in αβ T-cell development. We show that Dll3 cannot activate Notch when expressed in trans but like other Notch ligands it can inhibit Notch signalling when expressed in cis with the receptor. The loss of Dll3 leads to an increase in Hes5 expression in double positive thymocytes and their increased production of mature CD4+ and CD8+ T cells. Studies using competitive irradiation chimeras proved that Dll3 acts in a cell autonomous manner to regulate positive selection but not negative selection of autoreactive T cells. Our results indicate that Dll3 has a unique function during T-cell development that is distinct from the role played by the other DSL ligands of Notch and is in keeping with other recent studies indicating that Dll1 and Dll3 ligands have non-overlapping roles during embryonic development
Recommended from our members
Diagnosis and management of lobular capillary haemangioma (pyogenic granuloma) in an adult female lactating Bonobo (Pan paniscus)
An adult female lactating bonobo (Pan paniscus) presented with an acutely enlarging skin nodule, readily susceptible to haemorrhage, on the third digit of her left foot, which was subsequently removed under anaesthesia when it had reached a diameter of approximately 10 mm. The bonobo had five-year-old and three-month-old infants, which had to be managed sensitively during the procedure. Risk management was carefully planned with the keeping team. Oral benzodiazepines were used in the dam and five-year-old infant to reduce stress, and careful planning ensured a time-efficient anaesthetic procedure. Radiographs were taken to investigate the involvement of underlying tissue, and the skin mass was removed by partial amputation of the digit including a segment of bone. Histopathology yielded a diagnosis of lobular capillary haemangioma (pyogenic granuloma). Although the clinical presentation was extremely similar to that seen in humans, the entity has not been commonly reported in apes
Recommended from our members
Effect of nanostructured ceria as support for the iron catalysed hydrogenation of CO2 into hydrocarbons.
This paper demonstrates the key role of the property-structure relationship of the support on iron/ceria catalysts on the hydrocarbon selectivity and olefin-to-paraffin ratio for the direct hydrogenation of carbon dioxide into hydrocarbons. The effect is directly related to the reducibility of the different nanostructured ceria supports and their interaction with the iron particles. Herein, we demonstrate that the iron-based catalysts can be modified not only by the addition of promoters, commonly reported in the literature, but also by careful control of the morphology of the ceria support.The authors thanks the UK Engineering and Physical Science Research Council (EPSRC, grant numbers: EP/L020432/2 and EP/G03768X/1).This is the final version of the article. It first appeared from the Royal Society of Chemistry via http://dx.doi.org/10.1039/C5CP07788
Carbon sequestration and biodiversity following 18 years of active tropical forest restoration
Vast areas of degraded tropical forest, combined with increasing interest in mitigating climate change and conserving biodiversity, demonstrate the potential value of restoring tropical forest. However, there is a lack of long-term studies assessing active management for restoration. Here we investigate Above-Ground Biomass (AGB), forest structure, and biodiversity, before degradation (in old-growth forest), after degradation (in abandoned agricultural savanna grassland), and within a forest that is actively being restored in Kibale National Park, Uganda. In 1995 degraded land in Kibale was protected from fire and replanted with native seedlings (39 species) at a density of 400 seedlings ha-1. Sixty-five plots (50 m × 10 m) were established in restoration areas in 2005 and 50 of these were re-measured in 2013, allowing changes to be assessed over 18 years. Degraded plots have an Above Ground Biomass (AGB) of 5.1 Mg dry mass ha-1, of which 80% is grass. By 2005 AGB of trees ≥10 cm DBH was 9.5 Mg ha-1, increasing to 40.6 Mg ha-1 by 2013, accumulating at a rate of 3.9 Mg ha-1 year-1. A total of 153 planted individuals ha-1 (38%) remained by 2013, contributing 28.9 Mg ha-1 (70%) of total AGB. Eighteen years after restoration, AGB in the plots was 12% of old-growth (419 Mg ha-1). If current accumulation rates continue restoration forest would reach old-growth AGB in a further 96 years. Biodiversity of degraded plots prior to restoration was low with no tree species and 2 seedling species per sample plot (0.05 ha). By 2005 restoration areas had an average of 3 tree and 3 seedling species per sample plot, increasing to 5 tree and 9 seedling species per plot in 2013. However, biodiversity was still significantly lower than old-growth forest, at 8 tree and 16 seedling species in an equivalent area. The results suggest that forest restoration is beneficial for AGB accumulation with planted stems storing the majority of AGB. Changes in biodiversity appear slower; possibly due to low stem turnover. Overall this restoration treatment is an effective means of restoring degraded land in the area, as can be seen from the lack of regeneration in degraded plots, which remain low-AGB and diversity, largely due to the impacts of fire and competition with grasses
How Exposures to Biologics Influence the Induction and Incidence of Asthma
A number of environmental factors can affect the development and severity of allergy and asthma; however, it can be argued that the most significant inhaled agents that modulate the development of these conditions are biologics. Sensitization to environmental allergens is an important risk factor for the development of asthma. Innate immune responses are often mediated by receptors on mononuclear cells whose primary ligands arise from microorganisms. Many pathogens, especially viruses, target epithelial cells and affect the host immune response to those pathogens. The acquired immune response to an allergen is influenced by the nature of the innate immune system. Products of innate immune responses to microbes promote T(H)1-acquired responses. In the absence of T(H)1 responses, T(H)2 responses can dominate. Central to T(H)1/T(H)2 balance is the composition of contaminants that derive from microbes. In this review we examine the biology of the response to allergens, viruses, and bacterial products in the context of the development of allergy and asthma
Can a falling tree make a noise in two forests at the same time?
It is a commonplace to claim that quantum mechanics supports the old idea
that a tree falling in a forest makes no sound unless there is a listener
present. In fact, this conclusion is far from obvious. Furthermore, if a
tunnelling particle is observed in the barrier region, it collapses to a state
in which it is no longer tunnelling. Does this imply that while tunnelling, the
particle can not have any physical effects? I argue that this is not the case,
and moreover, speculate that it may be possible for a particle to have effects
on two spacelike separate apparatuses simultaneously. I discuss the measurable
consequences of such a feat, and speculate about possible statistical tests
which could distinguish this view of quantum mechanics from a ``corpuscular''
one. Brief remarks are made about an experiment underway at Toronto to
investigate these issues.Comment: 9 pp, Latex, 3 figs, to appear in Proc. Obsc. Unr. Conf.; Fig 2
postscript repaired on 26.10.9
Hide and seek: The theory of mind of visual concealment and search
Researchers have investigated visual search behavior for almost a century. During that time, few studies have examined the cognitive processes involved in hiding items rather than finding them. To investigate this, we developed a paradigm that allowed participants to indicate where they would hide (or find) an item that was to be found (or hidden) by a friend or a foe. We found that (i) for friends more than foes, participants selected the pop-out item in the display, and (ii) when the display was homogeneous, they selected nearby and corner items. These behaviors held for both hiding and finding, although hide and find behaviors were not identical. For pop-out displays, decision times were unusually long when hiding an item from a foe. These data converge on the conclusion that the principles of search and concealment are similar, but not the same. They also suggest that this paradigm will provide researchers a powerful method for investigating theory of mind in adults
Designing nutrition-based interventional trials for the future: addressing the known knowns
Abstract The consistent decline in critical illness mortality has a significant effect on trial design, whereby either an improbable effect sizes or large number of patients are required. The signal-to-noise ratio is of particular interest for the critically ill. When considering the potential signal, interventions need to match outcomes in regard to biological plausibility. Provision of nutrition is a complex decision with many underappreciated aspects of noise. However, a fundamental interaction is often not accounted for time. Working as a community to evolve trial design will be our challenge for nutrition interventions in the critically ill for the future
Spin-Nematic Squeezed Vacuum in a Quantum Gas
Using squeezed states it is possible to surpass the standard quantum limit of
measurement uncertainty by reducing the measurement uncertainty of one property
at the expense of another complementary property. Squeezed states were first
demonstrated in optical fields and later with ensembles of pseudo spin-1/2
atoms using non-linear atom-light interactions. Recently, collisional
interactions in ultracold atomic gases have been used to generate a large
degree of quadrature spin squeezing in two-component Bose condensates. For
pseudo spin-1/2 systems, the complementary properties are the different
components of the total spin vector , which fully characterize the state on
an SU(2) Bloch sphere. Here, we measure squeezing in a spin-1 Bose condensate,
an SU(3) system, which requires measurement of the rank-2 nematic or quadrupole
tensor as well to fully characterize the state. Following a quench
through a nematic to ferromagnetic quantum phase transition, squeezing is
observed in the variance of the quadratures up to -8.3(-0.7 +0.6) dB
(-10.3(-0.9 +0.7) dB corrected for detection noise) below the standard quantum
limit. This spin-nematic squeezing is observed for negligible occupation of the
squeezed modes and is analogous to optical two-mode vacuum squeezing. This work
has potential applications to continuous variable quantum information and
quantum-enhanced magnetometry
No effect of repeated post-resistance exercise cold or hot water immersion on in-season body composition and performance responses in academy rugby players: a randomised controlled cross-over design
Following resistance exercise, uncertainty exists as to whether the regular application of cold water immersion attenuates lean muscle mass increases in athletes. The effects of repeated post-resistance exercise cold versus hot water immersion on body composition and neuromuscular jump performance responses in athletes were investigated. Male, academy Super Rugby players (n = 18, 19.9 ± 1.5 y, 1.85 ± 0.06 m, 98.3 ± 10.7 kg) participated in a 12-week (4-week × 3-intervention, i.e., control [CON], cold [CWI] or hot [HWI] water immersion) resistance exercise programme, utilising a randomised cross-over pre-post-design. Body composition measures were collected using dual-energy X-ray absorptiometry prior to commencement and every fourth week thereafter. Neuromuscular squat (SJ) and counter-movement jump (CMJ) performance were measured weekly. Linear mixed-effects models were used to analyse main (treatment, time) and interaction effects. There were no changes in lean (p = 0.960) nor fat mass (p = 0.801) between interventions. CON (p = 0.004) and CWI (p = 0.003) increased (g = 0.08-0.19) SJ height, compared to HWI. There were no changes in CMJ height (p = 0.482) between interventions. Repeated post-resistance exercise whole-body CWI or HWI does not attenuate (nor promote) increases in lean muscle mass in athletes. Post-resistance exercise CON or CWI results in trivial increases in SJ height, compared to HWI. During an in-season competition phase, our data support the continued use of post-resistance exercise whole-body CWI by athletes as a recovery strategy which does not attenuate body composition increases in lean muscle mass, while promoting trivial increases in neuromuscular concentric-only squat jump performance. [Abstract copyright: © 2022. The Author(s).
- …