Loss of constitutive activity is correlated with increased thermostability of the human adenosine A2A receptor

BACKGROUND AND PURPOSE: Thermostabilization by mutagenesis is one method which has facilitated the determination of high-resolution structures of the adenosine A(2A) receptor (A(2A)R). Sets of mutations were identified, which both thermostabilized the receptor and resulted in preferential agonist (Rag23 mutant) or antagonist (Rant5 and Rant21) binding forms as assessed by radioligand binding analysis. While the ligand-binding profiles of these mutants are known, the effects these mutations have on receptor activation and downstream signalling are less well characterized. EXPERIMENTAL APPROACH: Here we have investigated the effects of the thermostabilizing mutations on receptor activation using a yeast cell growth assay. The assay employs an engineered Saccharomyces cerevisiae, MMY24, which couples receptor activation to cell growth. KEY RESULTS: Analysis of the receptor activation profile revealed that the wild-type (WT) A(2A)R had considerable constitutive activity. In contrast, the Rag23, Rant5 and Rant21 thermostabilized mutants all exhibited no constitutive activity. While the preferentially antagonist-binding mutants Rant5 and Rant21 showed a complete lack of agonist-induced activity, the Rag23 mutant showed high levels of agonist-induced receptor activity. Further analysis using a mutant intermediate between Rag23 and WT indicated that the loss of constitutive activity observed in the agonist responsive mutants was not due to reduced G-protein coupling. CONCLUSIONS AND IMPLICATIONS: The loss of constitutive activity may be an important feature of these thermostabilized GPCRs. In addition, the constitutively active and agonist-induced active conformations of the A(2A)R are distinct

Loss of constitutive activity is correlated with increased thermostability of the human adenosine A2A receptor

In this note we present an explicit realization of the affine vertex algebra V^cri(gl(1|1)) inside of the tensor product F ⊗ M where F is a fermionic verex algebra and M is a commutative vertex algebra. This immediately gives an alternative description of the center of V^cri(gl(1|1)) as a subalgebra M_0 of M. We reconstruct the Molev-Mukhin formula for the Hilbert-Poincare series of the center of V^cri(gl(1|1)). Moreover, we construct a family of irreducible Vcri(gl(1|1))-modules realized on F and parameterized by χ+, χ- ∈ C((z)). We propose a generalization of V^cri(gl(1|1)) as a critical level version of the super W_{1+∞} vertex algebra

Improving the scalability of parallel N-body applications with an event driven constraint based execution model

The scalability and efficiency of graph applications are significantly constrained by conventional systems and their supporting programming models. Technology trends like multicore, manycore, and heterogeneous system architectures are introducing further challenges and possibilities for emerging application domains such as graph applications. This paper explores the space of effective parallel execution of ephemeral graphs that are dynamically generated using the Barnes-Hut algorithm to exemplify dynamic workloads. The workloads are expressed using the semantics of an Exascale computing execution model called ParalleX. For comparison, results using conventional execution model semantics are also presented. We find improved load balancing during runtime and automatic parallelism discovery improving efficiency using the advanced semantics for Exascale computing.Comment: 11 figure

Overstating the evidence - double counting in meta-analysis and related problems

Background: The problem of missing studies in meta-analysis has received much attention. Less attention has been paid to the more serious problem of double counting of evidence. Methods: Various problems in overstating the precision of results from meta-analyses are described and illustrated with examples, including papers from leading medical journals. These problems include, but are not limited to, simple double-counting of the same studies, double counting of some aspects of the studies, inappropriate imputation of results, and assigning spurious precision to individual studies. Results: Some suggestions are made as to how the quality and reliability of meta-analysis can be improved. It is proposed that the key to quality in meta-analysis lies in the results being transparent and checkable. Conclusions: Existing quality check lists for meta-analysis do little to encourage an appropriate attitude to combining evidence and to statistical analysis. Journals and other relevant organisations should encourage authors to make data available and make methods explicit. They should also act promptly to withdraw meta-analyses when mistakes are found

Formulation of complementary food using amaranth, chickpea and maize improves iron, calcium and zinc content

Malnutrition is the cause of the majority of deaths in children under five years old in Ethiopia. Micronutrient deficiencies such as iron, zinc and calcium, often seen in malnourished children, are major public health problems throughout Ethiopia. These deficiencies have negative consequences on the cognitive and physical development of children, and on work productivity of adults. There is, therefore, a need for sustainable methods to address iron inadequacy in complementary feeding. Animal products are a good source of iron, zinc and calcium, but due to their high costs, their consumption by most children in Ethiopia has declined. The grain amaranth grows wild in areas of Ethiopia but is considered a weed. This study, conducted in rural Ethiopia, was initiated to prepare nutrient-rich complementary food using recipes that substituted the usual maize gruel with porridge made from amaranth and chickpea flours. Using a laboratory based experimental study design, four porridges suitable for complementary feeding, with different proportions of amaranth grains, maize and chickpeas were formulated in triplicate and analyzed in triplicate for minerals including iron, and phytate levels. Mother-child pairs were recruited for acceptability testing, at the community level. Results showed adding amaranth improved the content of iron and other nutrients as compared to control porridge (100% maize) and decreased phytate levels. The lowest phytate to iron ratio (0.24) was observed in the 70% amaranth and 30% chickpea blend, and the lowest viscosity measure was also observed in this same formulation. Soaking amaranth seeds in warm (50oC) water then germinating in lemon juice-containing water at 32oC for 72 hours resulted in the lowest phytate levels. In sensory testing, all of the formulated porridges with different proportions of amaranth flour were acceptable to mothers and their children, although the red color was disliked by mothers and their children. Flavor preference was not altered; however, overall acceptability was reduced with increasing amounts of amaranth. The study indicated that a processed 70% amaranth and 30% chickpea product can be used to produce low-cost, nutrient-rich complementary food with moderate acceptability. Increased nutritional awareness, production and consumption of grain amaranth products may be the way to address mineral deficiencies including iron, in the study area.Keywords: Micronutrients, Phytates, Complementary feeding, Amaranth grain, Chickpea, Ethiopia, Iron, Zinc

Randomised feasibility trial into the effects of low-frequency electrical muscle stimulation in advanced heart failure patients.

OBJECTIVES: Low-frequency electrical muscle stimulation (LF-EMS) may have the potential to reduce breathlessness and increase exercise capacity in the chronic heart failure population who struggle to adhere to conventional exercise. The study's aim was to establish if a randomised controlled trial of LF-EMS was feasible. DESIGN AND SETTING: Double blind (participants, outcome assessors), randomised study in a secondary care outpatient cardiac rehabilitation programme. PARTICIPANTS: Patients with severe heart failure (New York Heart Association class III-IV) having left ventricular ejection fraction <40% documented by echocardiography were eligible. INTERVENTIONS: Participants were randomised (remotely by computer) to 8 weeks (5×60 mins per week) of either LF-EMS intervention (4 Hz, continuous, n=30) or sham placebo (skin level stimulation only, n=30) of the quadriceps and hamstrings muscles. Participants used the LF-EMS straps at home and were supervised weekly OUTCOME MEASURES: Recruitment, adherence and tolerability to the intervention were measured during the trial as well as physiological outcomes (primary outcome: 6 min walk, secondary outcomes: quadriceps strength, quality of life and physical activity). RESULTS: Sixty of 171 eligible participants (35.08%) were recruited to the trial. 12 (20%) of the 60 patients (4 LF-EMS and 8 sham) withdrew. Forty-one patients (68.3%), adhered to the protocol for at least 70% of the sessions. The physiological measures indicated no significant differences between groups in 6 min walk distance(p=0.13) and quality of life (p=0.55) although both outcomes improved more with LF-EMS. CONCLUSION: Patients with severe heart failure can be recruited to and tolerate LF-EMS studies. A larger randomised controlled trial (RCT) in the advanced heart failure population is technically feasible, although adherence to follow-up would be challenging. The preliminary improvements in exercise capacity and quality of life were minimal and this should be considered if planning a larger trial. TRIAL REGISTRATION NUMBER: ISRCTN16749049

Optimum mask and source patterns to print a given shape

Proceedings of S P I E - the International Society for OpticalNew degrees of freedom can be optimized in mask shapes when the source is also adjustable, because required image symmetries can be provided by the source rather than the collected wavefront. The optimized mask will often consist of novel sets of shapes that are quite different in layout from the target IC patterns. This implies that the optimization algorithm should have good global convergence properties, since the target patterns may not be a suitable starting solution. We have eveloped an algorithm that can optimize mask and source without using a starting design. Examples are shown where the process window obtained is between 2 and 6 times larger than that achieved with standard RET methods. The optimized masks require phase shift, but no trim mask is used. Thus far we have only optimized 2D patterns over small fields (periodicities of 1im or less). We also discuss mask optimization with fixed source, source optimization with fixed mask, and the re-targeting of designs in different mask regions to provide a common exposure level.published_or_final_versio