306 research outputs found

    Fluctuations of conserved charges at finite temperature from lattice QCD

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    We present the full results of the Wuppertal-Budapest lattice QCD collaboration on flavor diagonal and non-diagonal quark number susceptibilities with 2+1 staggered quark flavors, in a temperature range between 125 and 400 MeV. The light and strange quark masses are set to their physical values. Lattices with Nt=6, 8, 10, 12, 16 are used. We perform a continuum extrapolation of all observables under study. A Symanzik improved gauge and a stout-link improved staggered fermion action is utilized. All results are compared to the Hadron Resonance Gas model predictions: good agreement is found in the temperature region below the transition.Comment: 13 pages, 8 figures in Jhep styl

    Quark Number Susceptibility with Finite Chemical Potential in Holographic QCD

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    We study the quark number susceptibility in holographic QCD with a finite chemical potential or under an external magnetic field at finite temperature. We first consider the quark number susceptibility with the chemical potential. We observe that approaching the critical temperature from high temperature regime, the quark number susceptibility divided by temperature square develops a peak as we increase the chemical potential, which confirms recent lattice QCD results. We discuss this behavior in connection with the existence of the critical end point in the QCD phase diagram. We also consider the quark number susceptibility under the external magnetic field. We predict that the quark number susceptibility exhibits a blow-up behavior at low temperature as we raise the value of the magnetic field. We finally spell out some limitations of our study.Comment: 25 pages, 3 figures, published versio

    TRIB2 confers resistance to anti-cancer therapy by activating the serine/threonine protein kinase AKT.

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    Intrinsic and acquired resistance to chemotherapy is the fundamental reason for treatment failure for many cancer patients. The identification of molecular mechanisms involved in drug resistance or sensitization is imperative. Here we report that tribbles homologue 2 (TRIB2) ablates forkhead box O activation and disrupts the p53/MDM2 regulatory axis, conferring resistance to various chemotherapeutics. TRIB2 suppression is exerted via direct interaction with AKT a key signalling protein in cell proliferation, survival and metabolism pathways. Ectopic or intrinsic high expression of TRIB2 induces drug resistance by promoting phospho-AKT (at Ser473) via its COP1 domain. TRIB2 expression is significantly increased in tumour tissues from patients correlating with an increased phosphorylation of AKT, FOXO3a, MDM2 and an impaired therapeutic response. This culminates in an extremely poor clinical outcome. Our study reveals a novel regulatory mechanism underlying drug resistance and suggests that TRIB2 functions as a regulatory component of the PI3K network, activating AKT in cancer cells

    CR1 — a dispersed repeated element associated with the Cab-1 locus in tomato

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    Cab-1 is a complex genetic locus in tomato consisting of four clustered genes encoding chlorophyll a/b-binding polypeptide. Southern blot analysis of total tomato DNA with genomic clones corresponding to the Cab-1 locus has revealed the presence of a repetitive element in the 3 kb spacer regions between two of these genes. This repetitive element, named CR1, has been characterized via sequencing, genetic mapping and hybridization to related solanaceous species. Results indicate that there are as many as 30 copies of this element in the tomato genome and that most, if not all, are found at independent loci. Sites corresponding to 12 of the repeats have been located on different regions of chromosomes 2, 4, 5, 7, 10 and 11. A 1.6 kb Pst I- Eco RI fragment from the Cab-1 locus containing the element was sequenced and found to be 75% AT-rich. No open reading frames larger than 150 bp were detected. Several imperfect inverted repeats flanked by direct repeats could be found at the ends of the element. This arrangement is reminiscent of known transposons. Southern hybridization analysis indicates that multiple copies of CR1 exist in all species of the genus Lycopersicon as well as in Solanum lycopersicoides and S. tuberosum (potato), but not in eggplant, pepper, petunia, Datura or tobacco. Melt-off experiments indicate that members of the CR1 family in the tomato genome are more closely related to one another than to homologous members in the genomes of S. lycopersicoides or S. tuberosum , suggesting some type of concerted evolution.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43418/1/11103_2004_Article_BF00014948.pd

    A model study of quark number susceptibility at finite temperature beyond rainbow-ladder approximation

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    In this paper we calculate the quark number susceptibility (QNS) of QCD at finite temperature under the rainbow-ladder and Ball-Chiu type truncation schemes of the Dyson-Schwinger approach. It is found that the difference between the result of the rainbow-ladder truncation and that of Ball-Chiu type truncation is small, which shows that the dressing effect of the quark-gluon vertex on the QNS at finite temperature is small. It is also found that at low temperature the quark number susceptibility is nearly zero and it increases sharply when the temperature approaches the chiral phase transition point. A comparison between the result in the present paper with those in the literature is made.Comment: 17 pages, 6 figure

    Insomnia symptoms and repressive coping in a sample of older Black and White women

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    BACKGROUND: This study examined whether ethnic differences in insomnia symptoms are mediated by differences in repressive coping styles. METHODS: A total of 1274 women (average age = 59.36 ± 6.53 years) participated in the study; 28% were White and 72% were Black. Older women in Brooklyn, NY were recruited using a stratified, cluster-sampling technique. Trained staff conducted face-to-face interviews lasting 1.5 hours acquiring sociodemographic data, health characteristics, and risk factors. A sleep questionnaire was administered and individual repressive coping styles were assessed. Fisher's exact test and Spearman and Pearson analyses were used to analyze the data. RESULTS: The rate of insomnia symptoms was greater among White women [74% vs. 46%; χ(2 )= 87.67, p < 0.0001]. Black women scored higher on the repressive coping scale than did White women [Black = 37.52 ± 6.99, White = 29.78 ± 7.38, F(1,1272 )= 304.75, p < 0.0001]. We observed stronger correlations between repressive coping and insomnia symptoms for Black [r(s )= -0.43, p < 0.0001] than for White women [r(s )= -0.18, p < 0.0001]. Controlling for variation in repressive coping, the magnitude of the correlation between ethnicity and insomnia symptoms was substantially reduced. Multivariate adjustment for differences in sociodemographics, health risk factors, physical health, and health beliefs and attitudes had little effect on the relationships. CONCLUSION: Relationships between ethnicity and insomnia symptoms are jointly dependent on the degree of repressive coping, suggesting that Black women may be reporting fewer insomnia symptoms because of a greater ability to route negative emotions from consciousness. It may be that Blacks cope with sleep problems within a positive self-regulatory framework, which allows them to deal more effectively with sleep-interfering psychological processes to stressful life events and to curtail dysfunctional sleep-interpreting processes

    More Evidence that Depressive Symptoms Predict Mortality in COPD Patients: Is Type D Personality an Alternative Explanation?

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    The present study attempted to replicate our previous finding that depressive symptoms are a risk factor for mortality in stable chronic obstructive pulmonary disease (COPD), but in a different population with a different measure of depressive symptoms. We further investigated whether type D personality is associated with mortality in patients with COPD and whether it explains any relationship observed between depressive symptoms and mortality. In 122 COPD patients, mean age 60.8 +/- 10.3 years, 52% female, and mean forced expiratory volume in 1 s (FEV(1)) 41.1 +/- 17.6%pred, we assessed body mass index, post bronchodilator FEV(1), exercise capacity, depressive symptoms with the Hospital Anxiety and Depression Scale, and type D with the Type D Scale. In the 7 years follow-up, 48 (39%) deaths occurred. The median survival time was 5.3 years. Depressive symptoms (hazard ratio = 1.07, 95% confidence intervals = 1.00-1.14) were an independent risk factor for mortality. Type D was not associated with mortality. We can rule out type D as an explanation for the relationship between depressive symptoms and mortality observed in this sample. However, ambiguity remains as to the interpretation of the value of depressive symptoms in predicting death
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