2,431 research outputs found

    Possible Local Spiral Counterparts to Compact Blue Galaxies at Intermediate Redshift

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    We identify nearby disk galaxies with optical structural parameters similar to those of intermediate-redshift compact blue galaxies. By comparing HI and optical emission-line widths, we show that the optical widths substantially underestimate the true kinematic widths of the local galaxies. By analogy, optical emission-line widths may underrepresent the masses of intermediate-z compact objects. For the nearby galaxies, the compact blue morphology is the result of tidally-triggered central star formation: we argue that interactions and minor mergers may cause apparently compact morphology at higher redshift.Comment: 5 pages, uses emulateapj5 and psfig. To appear in ApJ

    Does the toe-touch test predict hamstring injury in Australian Rules footballers?

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    This prospective cohort study evaluated the relationship of hamstring and lumbar spine flexibility to hamstring injury. Sixty–seven senior male Australian Rules footballers were videotaped while performing a toe-touch test from erect standing. The Peak Motion Measurement System was used to obtain measurements of end range hip flexion, lumbar flexion, toe-touch distance (TTD) and the ratio of lumbar spine flexion to hip flexion. Over the following football season, eight subjects (11.9 per cent) sustained a hamstring strain. Results showed no significant difference between the hamstring injured or uninjured players for any of the measured variables with no variable able to predict the likelihood of injury (p > 0.05). In this cohort, the toe-touch test would not appear to be a useful screening tool to identify footballers at risk for hamstring strain

    Novel antibody-based biosensors for the detection of haptens, proteins and whole cells

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    The modification of basic sensor platforms, incorporating specially designed materials, enhances the capacity for the development of new and improved biosensors. Novel transduction strategies employ surface modification technologies as a key element in the detection of biologically important molecules. These modifications can be chemical, electrochemical or physical. Surface modification of polymer substrates for blochip applications, thin-film deposition of biocompatible surfaces for implants and electropolymerisation of electrodes for immunoassay development are the basis of much of the research described in this thesis. A number of immunosensing methods were investigated for the generahon of improved biosensors for the detection of small haptens, proteins and whole cells. These Included fluorescence, chemiluminescence and impedance-based detection systems. Microtitre plates, polymer chps, fluorescence-enhancement chips and screen-printed electrodes were all examined. The specific targets chosen were Internalin B@dB), an mnvasion-associated proteln of Listerla monocytogenes, parvovirus B19, the first human parvovirus and warfarin, the ninth most prescribed drug in the world. A panel of antibodies and antibody fragments directed against InlB (previously produced) was used for the development of fluorescence and impedance-based assays. A recombinant form of the InlB protein was cloned, expressed ~n E.coli and purified by immobilised metal affinity chromatography (IMAC). An epitope mapping study of InlB was also performed, whereby the recombinant protein was portioned into three fragments to estabhsh the relative location of antibody-bindmg epitopes on its structure. The Listeria monocytogenes-derived proteins, peptides and anhbodies were characterised using plate-based methods and subsequently used for the development of immunoassays using novel fluorescent labels and an impedimettic sensor. The recomb~nant InlB-derived peptides were also cloned Into the PAC 4 vector for in vrvo biotinylation, expressed in E. coli and purif~ed using a monomeric streptavidin affinity column. The m vrvo hiotinylated fragments were characterised using SDS-PAGE, Western blotting, lmmunoassay and BiacoreTM (Chapter 3). Quantum dots and phosphorescent porphyrins were used as labels in the generation of solidphase immunoassays. Fluorescence-based munoassays using functionalised dye-doped nanoparticles were also developed. These doped particles were conjugated to specific antibodies and proteins using various surface mohfication techniques. The optimisation of solid-phase fluorescence-based immunoassays, incorporating labelled antibody-nanoparticle conjugates, for the detection of hIgG was investigated. A number of plate-based assay formats for the detection of parvovirus B19 was also investigated, in conjunction with an industrial partner; Biotnn International Ltd. Enzyme, chemiluminescence and fluorescencebased detection strategies were employed. A series of immobilisation studies was performed to study biomolecule attachment onto cone platforms for detection. (Chapter 4) Platform technologies using carbon screen-printed electrodes and ultra-thin polymer coatings for antibody-based biosensors were also examined. Antibodies directed against InlB were depos~tedo nto electrodes within conducting polyaniline (PANI) films to produce conductive affl~nty matrices with clearly defined binding characteristics. The binding of specific anhbodies to their target molecules was monitored via electrical impedance spectroscopy (EIS) , as the films function as labelfree reversible immuno-biosensors, when interrogated with a pulsed potential waveform (Chapter 5). Finally, the thin-film deposition of biocompatible surfaces for implants was also studied. The adhesion of thin-films to 316L stainless steel substrates was investigated. These films were prepared by plasma-enhanced chemical vapour deposition (PECVD) of hexamethyldisiloxane W S O ) and oxygen mixtures. The film properties were found to be dependent on the Oxygen/HMDSO flow ratio and RF (radio frequency) power. Biocompatibility studies were camed out using rat aortic smooth muscle (RASM) cells. Cell proliferation, viability and toxicity were assessed using commercial kits and scanning electron microscopy (SEM) was performed on substrates post incubation in culture to monitor the biocompatibility effects of the films (Appendix)

    Classical and alternative nuclear factor-kappaB in epithelium: impacts in allergic airway disease and avenues for redox regulation

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    Nuclear Factor kappaB (NF-êB) is a transcription factor whose activation is increased in settings of allergic asthma. At least two parallel NF-êB pathways exist: the classical pathway, which plays a role in inflammation and cell survival, and the alternative pathway, which regulates lymphoid cell development and organogenesis. The classical NF-êB pathway regulates inflammatory responses derived from lung epithelial cells; however, the role of the alternative pathway in lung epithelial cells remains unclear. We demonstrate that both classical and alternative NF-êB are activated in lung epithelial cells in response to multiple pro-inflammatory agonists, and siRNA-mediated knockdown of alternative NF-êB proteins largely attenuates pro-inflammatory cytokine production. Furthermore, simultaneous activation of both pathways leads to cooperative increases in pro-inflammatory responses, indicating a potential role for both classical and alternative NF-êB in the regulation of epithelial-derived pro-inflammatory responses. NF-êB activation in the epithelium modulates allergic inflammation in mouse models of allergic airway disease, however, its role in the context of an allergen relevant to human asthma remains unknown. In order to address the impact of inhibition of NF-êB in the epithelium in vivo, we utilized a House Dust Mite (HDM)-induced model of allergic airway disease. We demonstrate that HDM exposure activates classical and alternative NF-êB in both murine lung epithelium and human bronchial epithelial cells. Furthermore, following exposure to HDM, airway hyperresponsiveness, neutrophilic inflammation, and remodeling are attenuated in transgenic CC10-NF-êBSR (airway epithelial specific inhibitor of classical and alternative NF-êB) mice in comparison to wild type mice. Our data also demonstrate that specific knockdown of the alternative NF-êB protein, RelB, in the lung partially protects against HDM-induced pro-inflammatory responses, indicating that both classical and alternative NF-êB are important in HDM-induced responses. NF-êB proteins are modified by the redox-dependent post-translational modification, S-glutathionylation, under conditions of oxidative stress. S-glutathionylation of IKKâ, an upstream kinase in the NF-êB pathway, is known to decrease its catalytic activity; however, it is unknown how S-glutathionylation of IKKâ occurs. GSTP is an enzyme that catalyzes protein S-glutathionylation under conditions of oxidative stress and has been associated with the development of allergic asthma. We aimed to determine whether GSTP regulates NF-êB signaling, S-glutathionylation of IKKâ, and pro-inflammatory cytokine production. We demonstrate that siRNA-mediated knockdown of GSTP modulates NF-êB activation, NF-êB transcriptional activity, and pro-inflammatory cytokine production in response to LPS, a component of a bacterial cell wall. Furthermore, we demonstrate that GSTP associates with IKKâ in response to agonist stimulation and dampens IKKâ-induced pro-inflammatory cytokine production, surprisingly, independent of its catalytic activity. We also show that GSTP associates with other proteins of the NF-êB pathway, indicating a potential dual mechanism for repression of NF-êB-induced signaling. These studies collectively demonstrate that classical and alternative NF-êB contribute to epithelial-derived inflammatory responses, and GSTP may be a novel target by which NF-êB can be regulated

    Time-series transcriptomics from cold, oxic subseafloor crustal fluids reveals a motile, mixotrophic microbial community

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Seyler, L. M., Trembath-Reichert, E., Tully, B. J., & Huber, J. A. Time-series transcriptomics from cold, oxic subseafloor crustal fluids reveals a motile, mixotrophic microbial community. Isme Journal, (2020), doi:10.1038/s41396-020-00843-4.The oceanic crustal aquifer is one of the largest habitable volumes on Earth, and it harbors a reservoir of microbial life that influences global-scale biogeochemical cycles. Here, we use time series metagenomic and metatranscriptomic data from a low-temperature, ridge flank environment representative of the majority of global hydrothermal fluid circulation in the ocean to reconstruct microbial metabolic potential, transcript abundance, and community dynamics. We also present metagenome-assembled genomes from recently collected fluids that are furthest removed from drilling disturbances. Our results suggest that the microbial community in the North Pond aquifer plays an important role in the oxidation of organic carbon within the crust. This community is motile and metabolically flexible, with the ability to use both autotrophic and organotrophic pathways, as well as function under low oxygen conditions by using alternative electron acceptors such as nitrate and thiosulfate. Anaerobic processes are most abundant in subseafloor horizons deepest in the aquifer, furthest from connectivity with the deep ocean, and there was little overlap in the active microbial populations between sampling horizons. This work highlights the heterogeneity of microbial life in the subseafloor aquifer and provides new insights into biogeochemical cycling in ocean crust.The Gordon and Betty Moore Foundation sponsored most of the observatory components at North Pond through grant GBMF1609. This work was supported by NSF OCE-1062006, OCE-1745589 and OCE-1635208 to J.A.H. E.T.R. was supported by a NASA Postdoctoral Fellowship with the NASA Astrobiology Institute and a L’Oréal USA For Women in Science Fellowship. The Center for Dark Energy Biosphere Investigations (C-DEBI OCE-0939564) also supported the participation of J.A.H. and B.T. This is C-DEBI contribution number 548

    Forming Young Bulges within Existing Disks: Statistical Evidence for External Drivers

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    Contrary to traditional models of galaxy formation, recent observations suggest that some bulges form within preexisting disk galaxies. Such late-epoch bulge formation within disks seems to be linked to disk gas inflow and central star formation, caused by either internal secular processes or galaxy mergers and interactions. We identify a population of galaxies likely to be experiencing active bulge growth within disks, using the criterion that the color within the half-light radius is bluer than the outer disk color. Such blue-centered galaxies make up >10% of star-forming disk galaxies within the Nearby Field Galaxy Survey, a broad survey designed to represent the natural diversity of the low-z galaxy population over a wide range of luminosities and environments. Blue-centered galaxies correlate at 99% confidence with morphological peculiarities suggestive of minor mergers and interactions. From this and other evidence, we argue that external drivers rather than internal secular processes probably account for the majority of blue-centered galaxies. We go on to discuss quantitative plausibility arguments indicating that blue-centered evolutionary phases may represent an important mode of bulge growth for most disk galaxies, leading to significant changes in bulge-to-disk ratio without destroying disks. If this view is correct, bulge growth within disks may be a natural consequence of the repeated galaxy mergers and interactions inherent in hierarchical galaxy formation.Comment: 18 pages including 12 figures, AJ, accepte

    Investigating the role of early low-dose aspirin in diabetes: A phase III multicentre double-blinded placebo-controlled randomised trial of aspirin therapy initiated in the first trimester of diabetes pregnancy

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    Background: Preeclampsia, preterm birth and low birth weight represent key contributing factors to perinatal morbidity and mortality. Pregnancies complicated by type 1 and type 2 diabetes are at increased risk of these complications, which are purported to be largely attributed to placental dysfunction. Studies investigating a potential role for aspirin therapy in optimizing perinatal outcome have consistently failed to demonstrate a benefit among women with pre-existing diabetes, and yet widespread aspirin administration has become common practice in many centres. This study seeks to examine the effect of aspirin therapy, administered from the first trimester until 36 weeks gestation, on perinatal outcome in women with established pre-pregnancy diabetes. Our hypothesis is that aspirin therapy will reduce complications mediated by placental dysfunction, and improve perinatal outcomes. Methods: This phase III double-blinded, placebo-controlled randomized clinical trial will be conducted in seven tertiary-level perinatology centres in Ireland. Consenting participants who meet all eligibility criteria will be allocated randomly to either aspirin 150 mg once daily or matching placebo, commenced between 11 + 0 and 13 + 6 weeks. Allocation will take place electronically using software by Clininfo with randomization tables provided by the trial biostatistician. The primary outcome will be a composite clinical measure of placental dysfunction (preeclampsia, preterm birth before 34 weeks, birthweight below the 10th centile or perinatal mortality). This trial has been set up such that it is parallel in design and is a superiority study. No participants have been recruited yet. The trial has been registered with Eudra Clinical Trials - EudraCT Number 2018-000770-29. Funding for this trial was granted by the Health research Board (HRB) 1/9/2017(DIFA-2017-026). Discussion: Aspirin therapy has been investigated for the prevention of preeclampsia owing to its reduction on thromboxane production. Previous studies have failed to demonstrate a beneficial effect of aspirin on perinatal outcome amongst women with type I or type II diabetes. It is plausible that the failure to observe benefit to date, among the limited aspirin studies that have included participants with diabetes, may be a consequence of aspirin initiation too late in pregnancy to exert any effect on placentation. We believe that if aspirin is to be used for the prevention of placental dysfunction, it must be initiated before the second active phase of trophoblast invasion, which takes place from 14 weeks’ gestation onwards. No randomized trials investigating the role of aspirin in prevention of preeclampsia in pregnancies complicated by diabetes have previously initiated treatment in the first trimester, the gestational period at which it is most likely to exert an effect on placentation

    The Tully-Fisher Relation as a Measure of Luminosity Evolution: A Low Redshift Baseline for Evolving Galaxies

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    We use optical rotation curves to investigate the R-band Tully-Fisher properties of a sample of 90 spiral galaxies in close pairs. The galaxies follow the Tully-Fisher relation remarkably well, with the exception of eight distinct 3-sigma outliers. Although most of the outliers show signs of recent star formation, gasdynamical effects are probably the dominant cause of their anomalous Tully-Fisher properties. Four outliers with small emission line widths have very centrally concentrated line emission and truncated rotation curves; the central emission indicates recent gas infall after a close galaxy-galaxy pass. These four galaxies may be local counterparts to compact, blue galaxies at intermediate redshift. The remaining galaxies have a negligible offset from the reference Tully-Fisher relation, but a shallower slope (2.6-sigma significance) and a 25% larger scatter. We characterize the non-outlier sample with measures of distortion and star formation to search for third parameter dependence in the residuals of the TF relation. Severe kinematic distortion is the only significant predictor of TF residuals; this distortion is not, however, responsible for the slope difference from the reference distribution. Because the outliers are easily removed by sigma clipping, we conclude that even in the presence of some tidal distortion, detection of moderate luminosity evolution should be possible with high-redshift samples the size of this 90-galaxy study. (Abridged.)Comment: LaTeX document, 55 pages including 18 figures, to appear in A

    Close Galaxy Counts as a Probe of Hierarchical Structure Formation

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    Standard LCDM predicts that the major merger rate of galaxy-size dark matter halos rises rapidly with redshift. The average number of close companions per galaxy, Nc, is often used to infer the galaxy merger rate, however, recent observational studies suggest that Nc evolves very little with redshift. Here we use a "hybrid" N- body simulation plus analytic substructure model to predict Nc directly. We identify dark matter subhalos with galaxies and show that the observed lack of close pair count evolution arises because the high merger rate per halo at early times is counteracted by a decrease in the number of halos massive enough to host a galaxy pair. We compare our results to data compiled from the DEEP2, SSRS2, and the UZC redshift surveys. Observed pair counts match our predictions if we assume a monotonic mapping between galaxy luminosity and the maximum circular velocity that each subhalo had when it was first accreted onto its host halo. This suggests that satellite galaxies are significantly more resilient to destruction than are dissipationless dark matter subhalos. We argue that while Nc does not provide a direct measure of the halo merger rate, it offers a powerful means to constrain the Halo Occupation Distribution and the spatial distribution of galaxies within halos. Interpreted in this way, close pair counts provide a useful test of galaxy formation processes on < 100 kpc scales.Comment: 16 pages, 16 figures, minor change to figure 10, figure captions updated, typos corrected, Figure 4 corrected, version accepted for publication by Ap

    First Trimester Prediction of Uteroplacental Disease- Results of the Prospective Handle Study

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    To assess the ability of non-invasive cardiac output monitoring (NICOM), a novel method of non-invasive maternal hemodynamic assessment using bioreactance, in combination with first trimester biomarkers to predict the evolution of gestational hypertension (GH), pre-eclampsia (PE) and normotensive fetal growth restriction (FGR)
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