A Droplet within the Spherical Model

Various substances in the liquid state tend to form droplets. In this paper the shape of such droplets is investigated within the spherical model of a lattice gas. We show that in this case the droplet boundary is always diffusive, as opposed to sharp, and find the corresponding density profiles (droplet shapes). Translation-invariant versions of the spherical model do not fix the spatial location of the droplet, hence lead to mixed phases. To obtain pure macroscopic states (which describe localized droplets) we use generalized quasi-averaging. Conventional quasi-averaging deforms droplets and, hence, can not be used for this purpose. On the contrary, application of the generalized method of quasi-averages yields droplet shapes which do not depend on the magnitude of the applied external field.Comment: 22 pages, 2 figure

APPLICATION OF ENZYME-LINKED IMMUNOSORBENT ASSAY FOR AFLATOXIN CONTENT EVALUATION OF DIFFERENT POWDERED MILK AVALABLE IN ANAMBRA STATE, NIGERIA

The application of enzyme-link immunosorbent assay for aflatoxin contamination of 20 different powdered milk samples consumed within Anambra State, Nigeria was carried out primarily to ascertain their health implications. The samples were subjected to Ridascreen ELISA competitive enzyme immunoassay for the quantitative determination of aflatoxins in the milk. All the reagents required for the enzyme immunoassay including statndards were contained in the test kit used. Preparatory samples stages were grinding, extraction, filtration/centrifugation followed by acid mixture digestion process with tablet of selenium catalyst. The proximate analyses of the samples were done via AOAC standard procedures. The results revealed relatively low moisture contents with a range of 1.64 to 4.72%, with sample T recording highest value of 4.72% . The highest value of ash content was observed for sample D ( 6.57%) while sample R had lowest value of 0.85%. The lowest amount of crude fat was recorded by sample F (2.60%) as against high value of 21.33% for sample B.  Crude protein showed least amount in samples A (20.19%) with the highest amount found in sample H (23.67%). The quantification of aflatoxins in the 20 powdered milk samples using ELIZA method revealed relatively low concentration of aflatoxins in the samples and the trend observed had a range of 0.36ppm (sample B) to 0.81ppm (sample F). The average aflatoxin concentration was estimated to be 0.61ppm. Samples C, E and F had mean level of aflatoxin recorded as 0.71ppm while the mean amount implicated for samples A, B, G and K was 0.51ppm. Conclusively, the results of the proximate analysis of the milk samples revealed appreciable occurrence of crude protein and relatively low amount of aflatoxins. The level of aflatoxins in all the samples was found to occur below National Regulatory threshold value of 4ppm, hence all the samples analyzed can be adjudged to be safe for consumption with little precautionary measures for hygiene and preservation

Spherical Model in a Random Field

We investigate the properties of the Gibbs states and thermodynamic observables of the spherical model in a random field. We show that on the low-temperature critical line the magnetization of the model is not a self-averaging observable, but it self-averages conditionally. We also show that an arbitrarily weak homogeneous boundary field dominates over fluctuations of the random field once the model transits into a ferromagnetic phase. As a result, a homogeneous boundary field restores the conventional self-averaging of thermodynamic observables, like the magnetization and the susceptibility. We also investigate the effective field created at the sites of the lattice by the random field, and show that at the critical temperature of the spherical model the effective field undergoes a transition into a phase with long-range correlations $\sim r^{4-d}$.Comment: 29 page

Biased allosteric modulation at the CaS receptor engendered by structurally diverse calcimimetics

Background and Purpose Clinical use of cinacalcet in hyperparathyroidism is complicated by its tendency to induce hypocalcaemia, arising partly from activation of calcium-sensing receptors (CaS receptors) in the thyroid and stimulation of calcitonin release. CaS receptor allosteric modulators that selectively bias signalling towards pathways that mediate desired effects [e.g. parathyroid hormone (PTH) suppression] rather than those mediating undesirable effects (e.g. elevated serum calcitonin), may offer better therapies. Experimental Approach We characterized the ligand-biased profile of novel calcimimetics in HEK293 cells stably expressing human CaS receptors, by monitoring intracellular calcium (Ca2+i) mobilization, inositol phosphate (IP)1 accumulation, ERK1/2 phosphorylation (pERK1/2) and receptor expression. Key Results Phenylalkylamine calcimimetics were biased towards allosteric modulation of Ca2+i mobilization and IP1 accumulation. S,R-calcimimetic B was biased only towards IP1 accumulation. R,R-calcimimetic B and AC-265347 were biased towards IP1 accumulation and pERK1/2. Nor-calcimimetic B was unbiased. In contrast to phenylalkylamines and calcimimetic B analogues, AC-265347 did not promote trafficking of a loss-of-expression, naturally occurring, CaS receptor mutation (G670E). Conclusions and Implications The ability of R,R-calcimimetic B and AC-265347 to bias signalling towards pERK1/2 and IP1 accumulation may explain their suppression of PTH levels in vivo at concentrations that have no effect on serum calcitonin levels. The demonstration that AC-265347 promotes CaS receptor receptor signalling, but not trafficking reveals a novel profile of ligand-biased modulation at CaS receptors The identification of allosteric modulators that bias CaS receptor signalling towards distinct intracellular pathways provides an opportunity to develop desirable biased signalling profiles in vivo for mediating selective physiological responses

Counterion Condensation and Fluctuation-Induced Attraction

We consider an overall neutral system consisting of two similarly charged plates and their oppositely charged counterions and analyze the electrostatic interaction between the two surfaces beyond the mean-field Poisson-Boltzmann approximation. Our physical picture is based on the fluctuation-driven counterion condensation model, in which a fraction of the counterions is allowed to ``condense'' onto the charged plates. In addition, an expression for the pressure is derived, which includes fluctuation contributions of the whole system. We find that for sufficiently high surface charges, the distance at which the attraction, arising from charge fluctuations, starts to dominate can be large compared to the Gouy-Chapmann length. We also demonstrate that depending on the valency, the system may exhibit a novel first-order binding transition at short distances.Comment: 15 pages, 8 figures, to appear in PR

R-symmetric gauge mediation

We present a version of Gauge Mediated Supersymmetry Breaking which preserves an R-symmetry - the gauginos are Dirac particles, the A-terms are zero, and there are four Higgs doublets. This offers an alternative way for gauginos to acquire mass in the supersymmetry-breaking models of Intriligator, Seiberg, and Shih. We investigate the possibility of using R-symmetric gauge mediation to realize the spectrum and large sfermion mixing of the model of Kribs, Poppitz, and Weiner.Comment: 26+ pages, 3 figures, BIBTEX; v2 published version: references added, paragraph on spectrum running removed, section added on adjoint scalar masses, clarification of the meaning of Table 3 adde

Pooled resequencing of 122 ulcerative colitis genes in a large Dutch cohort suggests population-Specific associations of rare variants in MUC2

Genome-wide association studies have revealed several common genetic risk variants for ulcerative colitis (UC). However, little is known about the contribution of rare, large effect genetic variants to UC susceptibility. In this study, we performed a deep targeted resequencing of 122 genes in Dutch UC patients in order to investigate the contribution of rare variants to the genetic susceptibility to UC. The selection of genes consists of 111 established human UC susceptibility genes and 11 genes that lead to spontaneous colitis when knocked-out in mice. In addition, we sequenced the promoter regions of 45 genes where known variants exert cis-eQTL-effects. Targeted pooled re-sequencing was performed on DNA of 790 Dutch UC cases. The Genome of the Netherlands project provided sequence data of 500 healthy controls. After quality control and prioritization based on allele frequency and pathogenicity probability, follow-up genotyping of 171 rare variants was performed on 1021 Dutch UC cases and 1166 Dutch controls. Single-variant association and gene-based analyses identified an association of rare variants in the MUC2 gene with UC. The associated variants in the Dutch population could not be replicated in a German replication cohort (1026 UC cases, 3532 controls). In conclusion, this study has identified a putative role for MUC2 on UC susceptibility in the Dutch population and suggests a populationspecific contribution of rare variants to UC

Dark Matter Sees The Light

We construct a Dark Matter (DM) annihilation module that can encompass the predictions from a wide array of models built to explain the recently reported PAMELA and ATIC/PPB-BETS excesses. We present a detailed analysis of the injection spectrums for DM annihilation and quantitatively demonstrate effects that have previously not been included from the particle physics perspective. With this module we demonstrate the parameter space that can account for the aforementioned excesses and be compatible with existing high energy gamma ray and neutrino experiments. However, we find that it is relatively generic to have some tension between the results of the HESS experiment and the ATIC/PPB-BETS experiments within the context of annihilating DM. We discuss ways to alleviate this tension and how upcoming experiments will be able to differentiate amongst the various possible explanations of the purported excesses.Comment: 47 pages, 17 figure