Zero-point quantum fluctuations in cosmology

We re-examine the classic problem of the renormalization of zero-point quantum fluctuations in a Friedmann-Robertson-Walker background. We discuss a number of issues that arise when regularizing the theory with a momentum-space cutoff, and show explicitly how introducing non-covariant counter-terms allows to obtain covariant results for the renormalized vacuum energy-momentum tensor. We clarify some confusion in the literature concerning the equation of state of vacuum fluctuations. Further, we point out that the general structure of the effective action becomes richer if the theory contains a scalar field phi with mass m smaller than the Hubble parameter H(t). Such an ultra-light particle cannot be integrated out completely to get the effective action. Apart from the volume term and the Einstein-Hilbert term, that are reabsorbed into renormalizations of the cosmological constant and Newton's constant, the effective action in general also has a term proportional to F(phi)R, for some function F(phi). As a result, vacuum fluctuations of ultra-light scalar fields naturally lead to models where the dark energy density has the form rho_{DE}(t)=rho_X(t)+rho_Z(t), where rho_X is the component that accelerates the Hubble expansion at late times and rho_Z(t) is an extra contribution proportional to H^2(t). We perform a detailed comparison of such models with CMB, SNIa and BAO data.Comment: 23 pages, 9 figures. v3: refs added. To appear in Phys. Rev.

The M235T Polymorphism in the AGT Gene and CHD Risk: Evidence of a Hardy-Weinberg Equilibrium Violation and Publication Bias in a Meta-Analysis

BACKGROUND: The M235T polymorphism in the AGT gene has been related to an increased risk of hypertension. This finding may also suggest an increased risk of coronary heart disease (CHD). METHODOLOGY/PRINCIPAL FINDINGS: A case-cohort study was conducted in 1,732 unrelated middle-age women (210 CHD cases and 1,522 controls) from a prospective cohort of 15,236 initially healthy Dutch women. We applied a Cox proportional hazards model to study the association of the polymorphism with acute myocardial infarction (AMI) (n = 71) and CHD. In the case-cohort study, no increased risk for CHD was found under the additive genetic model (hazard ratio [HR] = 1.20; 95% confidence interval [CI], 0.86 to 1.68; P = 0.28). This result was not changed by adjustment (HR = 1.17; 95% CI, 0.83 to 1.64; P = 0.38) nor by using dominant, recessive and pairwise genetic models. Analyses for AMI risk under the additive genetic model also did not show any statistically significant association (crude HR = 1.14; 95% CI, 0.93 to 1.39; P = 0.20). To evaluate the association, a comprehensive systematic review and meta-analysis were undertaken of all studies published up to February 2007 (searched through PubMed/MEDLINE, Web of Science and EMBASE). The meta-analysis (38 studies with 13284 cases and 18722 controls) showed a per-allele odds ratio (OR) of 1.08 (95% CI, 1.01 to 1.15; P = 0.02). Moderate to large levels of heterogeneity were identified between studies. Hardy-Weinberg equilibrium (HWE) violation and the mean age of cases were statistically significant sources of the observed variation. In a stratum of non-HWE violation studies, there was no effect. An asymmetric funnel plot, the Egger's test (P = 0.066), and the Begg-Mazumdar test (P = 0.074) were all suggestive of the presence of publication bias. CONCLUSIONS/SIGNIFICANCE: The pooled OR of the present meta-analysis, including our own data, presented evidence that there is an increase in the risk of CHD conferred by the M235T variant of the AGT gene. However, the relevance of this weakly positive overall association remains uncertain because it may be due to various residual biases, including HWE-violation and publication biases

Cell-based screen for altered nuclear phenotypes reveals senescence progression in polyploid cells after Aurora kinase B inhibition.

Cellular senescence is a widespread stress response and is widely considered to be an alternative cancer therapeutic goal. Unlike apoptosis, senescence is composed of a diverse set of subphenotypes, depending on which of its associated effector programs are engaged. Here we establish a simple and sensitive cell-based prosenescence screen with detailed validation assays. We characterize the screen using a focused tool compound kinase inhibitor library. We identify a series of compounds that induce different types of senescence, including a unique phenotype associated with irregularly shaped nuclei and the progressive accumulation of G1 tetraploidy in human diploid fibroblasts. Downstream analyses show that all of the compounds that induce tetraploid senescence inhibit Aurora kinase B (AURKB). AURKB is the catalytic component of the chromosome passenger complex, which is involved in correct chromosome alignment and segregation, the spindle assembly checkpoint, and cytokinesis. Although aberrant mitosis and senescence have been linked, a specific characterization of AURKB in the context of senescence is still required. This proof-of-principle study suggests that our protocol is capable of amplifying tetraploid senescence, which can be observed in only a small population of oncogenic RAS-induced senescence, and provides additional justification for AURKB as a cancer therapeutic target.This work was supported by the University of Cambridge, Cancer Research UK, Hutchison Whampoa; Cancer Research UK grants A6691 and A9892 (M.N., N.K., C.J.T., D.C.B., C.J.C., L.S.G, and M.S.); a fellowship from the Uehara Memorial Foundation (M.S.).This is the author accepted manuscript. The final version is available from the American Society for Cell Biology via http://dx.doi.org/10.1091/mbc.E15-01-000

Wild species of vaccinium composition, nutritional value and utilization

There are still, in many parts of the globe, some edible fruit collects from the wild for human feeding and other uses. These fruits are utilised either in their raw nature or after some form of processing. One of these wild fruits are Vaccinium species such as Vaccinium myrtoides (Blume) Miq., Vaccinium cylindraceum, Vaccinium padifolium, Vaccinium corymbosum, Vaccinium myrtillus and others from the plant family Ericaceae. The term wild infers non-cultivated plants found in plantation felids or the forest. The species Vaccinium myrtoides and the others are small trees (shrubs) that are well known in Southeast Asian countries such as Philippines, Indonesia and other neighbouring islands. The plants classified as wild growing shrubs. However, the locals have made it be fully utilized in some areas as the wood that are used in grafting utensils and cutleries, or as fuel and fruits. The small-sized berry-like fruits with an average diameter of about 4–5 mm turn black when ripe. They have a delicious flavour that makes it edible and used in the making of other delicacies such as tart and pies to add flavour and as preservatives as well. A few published researches were done on Vaccinium myrtoides showing that it is still used in folkloric medicine. Leaves and fruits extracts showed strong antioxidant activity when tested in-vitro using DPPH (2, 2-diphenyl-1-picrylhydrazyl) free radical scavenging activity as part of a preliminary phytochemical screening for V. myrtoides. The study revealed that the antioxidant activity is due to the presence of flavonoids and other phenolic compounds in the plant leaves and fruit extracts

The effect of a micronutrient powder home fortification program on anemia and cognitive outcomes among young children in rural China: a cluster randomized trial

Abstract Background Anemia early in life has been associated with delayed cognitive and motor development. The WHO recommends home fortification using multiple micronutrient powders (MNPs) containing iron as a strategy to address anemia in children under two. We evaluated the effects of a program freely distributing MNP sachets to caregivers of infants in rural China. Methods We conducted a cluster-randomized controlled trial in Shaanxi province, enrolling all children aged 6–11 months in target villages. Following a baseline survey, investigators randomly assigned each village/cluster to a control or treatment group. In the treatment group, caregivers were instructed to give MNPs daily. Follow-up was after 6, 12, and 18 months of intervention. Primary outcomes were hemoglobin concentrations and scores on the Bayley Scales of Infant Development. Results One thousand, eight hundred and-two eligible children and their caregivers were enrolled. At baseline 48% (870) of children were anemic and 29% (529) were developmentally delayed. Six hundred and-ten children (117 villages) were assigned to the control group and 1192 children (234 villages) were assigned to the treatment group. Assignment to the treatment group was associated with an improvement in hemoglobin levels (marginal effect 1.77 g/L, 95% CI 0.017–3.520, p-value = 0.048) and cognitive development (marginal effect 2.23 points, 95% CI 0.061–4.399, p-value = 0.044) after 6 months but not thereafter. There were no significant effects on motor development. Zero effects after the first 6 months were not due to low compliance, low statistical power, or changes in feeding behavior. Hemoglobin concentrations improved in both the treatment and control groups over the course of the study; however, 22% (325) of children remained anemic at endline, and 48% (721) were cognitively delayed. Conclusions Providing caregivers with MNP sachets modestly hastened improvement in hemoglobin levels that was occurring absent intervention; however, this improvement did not translate into improved developmental outcomes at endline. Trial registration ISRCTN44149146 ; prospectively registered on 15th April 2013

Effect of fluorosis on dentine shear bond strength of a self-etching bonding system

WOS: 000186076000007PubMed ID: 14641674The purpose of this study was to investigate the effect of dental fluorosis on shear bond strength of a composite material to dentine. Forty human premolar teeth were classified according to the severity of fluorosis using the Thylstrup and Fejerskov index and were divided into four groups (TFI scores of 0, 3, 4 and 5) of 10 teeth. Non-fluorosed teeth (TFI score of 0) served as the control group. A self-etching light-cured bonding system, Clearfil SE Bond, and a micro-hybrid light-cured composite, Clearfil AP-X were selected for the study. Buccal surfaces of mounted teeth were ground flat to expose the dentine. Composite cylinders, 4 mm diameter and 4 mm length, were bonded to the treated dentine surfaces. Shear bond strength was measured with an universal testing machine at a cross-head speed of 0.5 mm min(-1). After failure, the fracture surfaces were examined under a stereo microscope. The mean bond strength was 24.37 +/- 3.54 MPa for non-fluorosed teeth and varied between 22.72 +/- 3.52 and 27.02 +/- 5.91 MPa for fluorosed teeth. The difference between the mean values for bond strength was not statistically significant (P > 0.05). Adhesive mode of failure was most prevalent in non-fluorosed teeth. It can be concluded that fluorosis does not affect the shear bond strength of composite material to human dentine