RXJ0142.0+2131: I. The galaxy content of an X-ray-luminous galaxy cluster at z=0.28

We present a photometric and spectroscopic study of stellar populations in the X-ray-luminous cluster of galaxies RXJ0142.0+2131 at z=0.280. This paper analyses the results of high signal-to-noise spectroscopy, as well as g'-, r'-, and i'-band imaging, using the Gemini Multi-Object Spectrograph on Gemini North. Of 43 spectroscopic targets, we find 30 cluster members over a range in color. Central velocity dispersions and absorption-line strengths for lines in the range 3700A < lambda_rest < 5800A are derived for cluster members, and are compared with a low-redshift sample of cluster galaxies, and single stellar population (SSP) models. We use a combination of these indicators to estimate luminosity-weighted mean ages, metallicities ([M/H]), and alpha-element abundance ratios ([alpha/Fe]). RXJ0142.0+2131 is a relatively poor cluster and lacks galaxies with high central velocity dispersions. Although the red sequence and the Faber-Jackson relation are consistent with pure passive evolution of the early-type population with a formation redshift of z_form = 2, the strengths of the 4000A break and scaling relations between metal line indices and velocity dispersion reject this model with high significance. By inverting SSP models for the Hbeta_G, Mgb, and line indices, we calculate that, at a given velocity dispersion and metallicity, galaxies in RXJ0142.0+2131 have luminosity-weighted mean ages 0.14 +- 0.07 dex older than the low-redshift sample. We also find that [alpha/Fe] in stellar populations in RXJ0142.0+2131 is 0.14 +- 0.03 greater than at low redshift. All scaling relations are consistent with these estimated offsets. (abridged)Comment: AJ, accepted. 31 pages, 13 figures, uses emulateapj.cls. High-resolution figures available on request from first autho

Lethal Mutagenesis of Picornaviruses with N-6-Modified Purine Nucleoside Analogues

RNA viruses exhibit extraordinarily high mutation rates during genome replication. Nonnatural ribonucleosides that can increase the mutation rate of RNA viruses by acting as ambiguous substrates during replication have been explored as antiviral agents acting through lethal mutagenesis. We have synthesized novel N-6-substituted purine analogues with ambiguous incorporation characteristics due to tautomerization of the nucleobase. The most potent of these analogues reduced the titer of poliovirus (PV) and coxsackievirus (CVB3) over 1,000-fold during a single passage in HeLa cell culture, with an increase in transition mutation frequency up to 65-fold. Kinetic analysis of incorporation by the PV polymerase indicated that these analogues were templated ambiguously with increased efficiency compared to the known mutagenic nucleoside ribavirin. Notably, these nucleosides were not efficient substrates for cellular ribonucleotide reductase in vitro, suggesting that conversion to the deoxyriboucleoside may be hindered, potentially limiting genetic damage to the host cell. Furthermore, a high-fidelity PV variant (G64S) displayed resistance to the antiviral effect and mutagenic potential of these analogues. These purine nucleoside analogues represent promising lead compounds in the development of clinically useful antiviral therapies based on the strategy of lethal mutagenesis

Pseudomonas aeruginosa quorum sensing molecules correlate with clinical status in cystic fibrosis

ABSTRACT Pseudomonas aeruginosa produces quorum sensing signal molecules that are potential biomarkers for infection. A prospective study of 60 cystic fibrosis patients with chronic P. aeruginosa, who required intravenous antibiotics for pulmonary exacerbations, was undertaken. Clinical measurements and biological samples were obtained at the start and end of the treatment period. Additional data were available for 29 of these patients when they were clinically stable. Cross-sectionally, quorum sensing signal molecules were detectable in the sputum, plasma and urine of 86%, 75% and 83% patients, respectively. They were positively correlated between the three biofluids. Positive correlations were observed for most quorum sensing signal molecules in sputum, plasma and urine, with quantitative measures of pulmonary P. aeruginosa load at the start of a pulmonary exacerbation. Plasma concentrations of 2-nonyl-4-hydroxy-quinoline (NHQ) were significantly higher at the start of a pulmonary exacerbation compared to clinical stability ( p<0.01). Following the administration of systemic antibiotics, plasma 2-heptyl-4-hydroxyquinoline ( p=0.02) and NHQ concentrations (p<0.01) decreased significantly. In conclusion, quorum sensing signal molecules are detectable in cystic fibrosis patients with pulmonary P. aeruginosa infection and are positively correlated with quantitative measures of P. aeruginosa. NHQ correlates with clinical status and has potential as a novel biomarker for P. aeruginosa infection

Constant photocurrent method to probe the sub-bandgap absorption in wide bandgap semiconductor films : the case of α-Ga2O3

The optical absorption coefficient is one of the fundamental properties of semiconductors and is critical to the development of optical devices. Herein, a revival of the constant photocurrent method is presented to measure sub-bandgap absorption in wide bandgap semiconductor films. The method involves maintaining a constant photocurrent by continually adjusting the impinging photon flux across the energy spectrum. Under such conditions, the reciprocal of the photon flux for uniformly absorbed light is proportional to the absorption coefficient. This method is applied to α-Ga 2O 3 and reveals that it can access the absorption coefficient from 1 × 10 5 cm −1 at the band edge (5.3 eV) to 0.8 cm −1 close to mid-bandgap (2.7 eV). Changes in the steepness of the absorption curve in the sub-bandgap region are in excellent agreement with defect states of α-Ga 2O 3 reported by deep level transient spectroscopy, indicating that the technique shows promise as a probe of energetically distributed defect states in thin film wide bandgap semiconductors

Yukawa Unification and the Superpartner Mass Scale

Naturalness in supersymmetry (SUSY) is under siege by increasingly stringent LHC constraints, but natural electroweak symmetry breaking still remains the most powerful motivation for superpartner masses within experimental reach. If naturalness is the wrong criterion then what determines the mass scale of the superpartners? We motivate supersymmetry by (1) gauge coupling unification, (2) dark matter, and (3) precision b-tau Yukawa unification. We show that for an LSP that is a bino-Higgsino admixture, these three requirements lead to an upper-bound on the stop and sbottom masses in the several TeV regime because the threshold correction to the bottom mass at the superpartner scale is required to have a particular size. For tan beta about 50, which is needed for t-b-tau unification, the stops must be lighter than 2.8 TeV when A_t has the opposite sign of the gluino mass, as is favored by renormalization group scaling. For lower values of tan beta, the top and bottom squarks must be even lighter. Yukawa unification plus dark matter implies that superpartners are likely in reach of the LHC, after the upgrade to 14 (or 13) TeV, independent of any considerations of naturalness. We present a model-independent, bottom-up analysis of the SUSY parameter space that is simultaneously consistent with Yukawa unification and the hint for m_h = 125 GeV. We study the flavor and dark matter phenomenology that accompanies this Yukawa unification. A large portion of the parameter space predicts that the branching fraction for B_s to mu^+ mu^- will be observed to be significantly lower than the SM value.Comment: 34 pages plus appendices, 20 figure

Spontaneous Autologous Graft-versus-Host Disease in Plasma Cell Myeloma Autograft Recipients: Flow Cytometric Analysis of Hematopoietic Progenitor Cell Grafts

Nine plasma cell myeloma patients spontaneously developed histologically proven autologous graft-versus-host disease (GVHD) limited predominantly to the gastrointestinal tract within 1 month of initial autologous hematopoietic cell transplantation (AHCT) using high-dose melphalan conditioning. All recipients responded promptly to systemic and nonabsorbable oral corticosteroid therapy. All patients previously received systemic therapy with thalidomide, lenalidomide, or bortezomib before AHCT. Using enzymatic amplification staining-enhanced flow cytometry, we evaluated expression of selected transcription regulators, pathway molecules, and surface receptors on samples of the infused hematopoietic cell grafts. We demonstrated significantly enhanced expression of GATA-2, CD130, and CXCR4 on CD34+ hematopoietic progenitor cells of affected patients compared with 42 unaffected AHCT controls. These 3 overexpressed markers have not been previously implicated in autologous GVHD. Although we did not specifically evaluate T cells, we postulate that exposure over time to the various immunomodulating therapies used for induction treatment affected not only the CD34+ cells but also T cells or relevant T cell subpopulations capable of mediating GVHD. After infusion, the affected hematopoietic progenitor cells then encounter a host that has been further altered by the high-dose melphalan preparative regimen; such a situation leads to the syndrome. These surface markers could be used to develop a model to predict development of this syndrome. Autologous GVHD potentially is a serious complication of AHCT and should be considered in plasma cell myeloma patients with otherwise unexplained gastrointestinal symptoms in the immediate post-AHCT period. Prompt recognition of this condition and protracted treatment with nonabsorbable or systemic corticosteroids or the combination may lead to resolution

In utero exposure to atrazine analytes and early menarche in the Avon Longitudinal Study of Parents and Children Cohort

Background: Evidence from experimental studies suggests that atrazine and its analytes alter the timing of puberty in laboratory animals. Such associations have not been investigated in humans. Objective: To determine the association between in utero exposure to atrazine analytes and earlier menarche attainment in a nested case-control study of the population-based Avon Longitudinal Study of Parents and Children. Methods: Cases were girls who reported menarche before 11.5 years while controls were girls who reported menarche at or after 11.5 years. Seven atrazine analyte concentrations were measured in maternal gestational urine samples (sample gestation week median (IQR): 12 (8–17)) during the period 1991–1992, for 174 cases and 195 controls using high performance liquid chromatography-tandem mass spectrometry. We evaluated the study association using multivariate logistic regression, adjusting for potential confounders. We used multiple imputation to impute missing confounder data for 29% of the study participants. Results: Diaminochlorotriazine (DACT) was the most frequently detected analyte (58%\u3elimit of detection [LOD]) followed by desethyl atrazine (6%), desethyl atrazine mercapturate (3%), atrazine mercapturate (1%), hydroxyl atrazine (1%), atrazine (1%) and desisopropyl atrazine (0.5%). Because of low detection of other analytes, only DACT was included in the exposure–outcome analyses. The adjusted odds of early menarche for girls with DACT exposures≥median was 1.13 (95% Confidence Interval [95% CI]:0.82, 1.55) and exposure Conclusions: This study is the first to examine the association between timing of menarche and atrazine analytes. We found a weak, non-significant association between in-utero exposure to atrazine metabolite DACT and early menarche, though the association was significant in the subset of girls with complete confounder information. Further exploration of the role of these exposures in female reproduction in other cohorts is needed

Associations of sitting accumulation patterns with cardio-metabolic risk biomarkers in Australian adults

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