229 research outputs found

    Proteome analysis of the hyaluronic acid-producing bacterium, Streptococcus zooepidemicus

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    Background: Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) is a commensal of horses and an opportunistic pathogen in many animals and humans. Some strains produce copious amounts of hyaluronic acid, making S. zooepidemicus an important industrial microorganism for the production of this valuable biopolymer used in the pharmaceutical and cosmetic industry. Encapsulation by hyaluronic acid is considered an important virulence factor in other streptococci, though the importance in S. zooepidemicus remains poorly understood. Proteomics may provide a better understanding of virulence factors in S. zooepidemicus, facilitate the design of better diagnostics and treatments, and guide engineering of superior production strains

    A new first-principles model to predict mild and deep surge for a centrifugal compressor

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    Centrifugal compressors are used in many applications, including automotive turbochargers. Surge is an instability that occurs at low mass flow rates that is often damaging. Even mild surge produces noise characteristics that cause problems with customer acceptance. It is therefore important to be able to predict both mild and deep surge onset. In existing literature, models resulting in cubic-shaped compressor characteristics have been developed from first principles. This paper extends these to include diffuser recirculation and show a new quintic-like shape for compressor characteristics which, for the first time, can differentiate between mild and deep surge. These characteristics are incorporated into a model for an experimental facility and resulting simulations show remarkable fit to experimental data. The model allows for variations in both space and time, so simulations can capture wave dynamics in the pipework. The model captures: stable operation, mild surge, transition from mild to deep surge, deep surge, and the potential for a stable quiet period beyond the surge limit. Furthermore, the model can provide physical explanations for the surge dynamics observed. This combined with the model's predictive ability will be of help to turbocharger manufacturers during early design stages, prior to experimental tests or detailed CFD studies.</p

    Metal-rich organic matter and hot continental passive margin: drivers for Devonian copper-cobalt-germanium mineralization in dolomitized reef-bearing carbonate platform

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    The abundance and types of reef-bearing carbonate platforms reflect the evolution of Devonian climate, with conspicuous microbial-algal reefs in the warm Early and Late Devonian and sponge-coral reefs in the cooler Middle Devonian. A dolomitized Wenlock-Lower Devonian microbial-algal reef-bearing carbonate platform hosts epigenetic copper-cobalt-germanium (Cu-Co-Ge) sulfide mineralization at Ruby Creek-Bornite in the Brooks Range, Alaska. Here, we present rhenium-osmium (Re-Os) radiometric ages and molybdenum and sulfur (δ(98/95)Mo = +2.04 to +5.48‰ and δ(34)S = −28.5 to −1.8‰) isotope variations for individual Cu-Co-Fe sulfide phases along the paragenetic sequence carrollite-bornite-pyrite. In the context of a hot, extensional passive margin, greenhouse conditions in the Early Devonian favored restriction of platform-top seawater circulation and episodic reflux of oxidized brines during growth of the carbonaceous carbonate platform. Molybdenum and sulfur isotope data signal the stepwise reduction of hot brines carrying Cu during latent reflux and geothermal circulation for at least ca. 15 million years from the Early Devonian until Cu-Co sulfide mineralization ca. 379–378 million years ago (Ma) in the Frasnian, Late Devonian (weighted mean of Re-Os model ages of carrollite at 379 ± 15 Ma [n = 4]; Re-Os isochron age of bornite at 378 ± 15 Ma [n = 6]). On the basis of petrographic relationships between sulfides and solid bitumen, and the Mo and S isotope data for sulfides, we imply that the endowment in critical metals (e.g., Co, Ge, Re) in the Ruby Creek-Bornite deposit is linked to the activity of primary producers that removed trace metals from the warm Early Devonian seawater and concentrated Co, Ge, and Re in algal-bacterial organic matter in carbonate sediments. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00126-022-01123-1

    Weapons Make the Man (Larger): Formidability Is Represented as Size and Strength in Humans

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    In order to determine how to act in situations of potential agonistic conflict, individuals must assess multiple features of a prospective foe that contribute to the foe's resource-holding potential, or formidability. Across diverse species, physical size and strength are key determinants of formidability, and the same is often true for humans. However, in many species, formidability is also influenced by other factors, such as sex, coalitional size, and, in humans, access to weaponry. Decision-making involving assessments of multiple features is enhanced by the use of a single summary variable that encapsulates the contributions of these features. Given both a) the phylogenetic antiquity of the importance of size and strength as determinants of formidability, and b) redundant experiences during development that underscore the contributions of size and strength to formidability, we hypothesize that size and strength constitute the conceptual dimensions of a representation used to summarize multiple diverse determinants of a prospective foe's formidability. Here, we test this hypothesis in humans by examining the effects of a potential foe's access to weaponry on estimations of that individual's size and strength. We demonstrate that knowing that an individual possesses a gun or a large kitchen knife leads observers to conceptualize him as taller, and generally larger and more muscular, than individuals who possess only tools or similarly mundane objects. We also document that such patterns are not explicable in terms of any actual correlation between gun ownership and physical size, nor can they be explained in terms of cultural schemas or other background knowledge linking particular objects to individuals of particular size and strength. These findings pave the way for a fuller understanding of the evolution of the cognitive systems whereby humans – and likely many other social vertebrates – navigate social hierarchies

    Powder Epoxy for One-Shot Cure, Out-of-Autoclave Applications: Lap Shear Strength and Z-Pinning Study

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    Large composite structures manufactured out-of-autoclave require the assembly and bonding of multiple parts. A one-shot cure manufacturing method is demonstrated using powder epoxy. Lap shear plates were manufactured from powder epoxy and glass fiber-reinforced plastic with four different bonding cases were assessed: secondary bonding using standard adhesive film, secondary bonding using powder epoxy, co-curing, and co-curing plus a novel Z-pinning method. This work investigates the lap shear strength of the four cases in accordance with ISO 4587:2003. Damage mechanisms and fracture behavior were explored using digital image correlation (DIC) and scanning electron microscopy (SEM), respectively. VTFA400 adhesive had a load at break 24.8% lower than secondary bonding using powder epoxy. Co-curing increased the load at break by 7.8% compared to powder epoxy secondary bonding, with the co-cured and pinned joint resulting in a 45.4% increase. In the co-cured and co-cured plus pinned cases, DIC indicated premature failure due to resin spew. SEM indicated shear failure of resin areas and a large amount of fiber pullout in both these cases, with pinning delaying fracture phenomena resulting in increased lap joint strength. This highlights the potential of powder epoxy for the co-curing of large composite structures out-of-autoclave

    How are normal sleeping controls selected? A systematic review of cross-sectional insomnia studies, and a standardised method to select healthy controls for sleep research

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    There appears to be some inconsistency in how normal sleepers (controls) are selected and screened for participation in research studies for comparison with insomnia patients. The purpose of the current study is to assess and compare methods of identifying normal sleepers in insomnia studies, with reference to published standards. We systematically reviewed the literature on insomnia patients which included control subjects. The resulting 37 articles were systematically reviewed with reference to the five criteria for normal sleep specified by Edinger et al. (2004). In summary, these criteria are: evidence of sleep disruption; sleep scheduling; general health; substance/medication use; and other sleep disorders. We found sleep diaries, PSG, and clinical screening examinations to be widely used with both control subjects and insomnia participants. However, there are differences between research groups in the precise definitions applied to the components of normal sleep. We found that none of reviewed studies applied all of the Edinger et al. criteria, and 16% met four criteria. In general, screening is applied most rigorously at the level of a clinical disorder, whether physical, psychiatric, or sleep. While the Edinger et al. criteria seem to be applied in some form by most researchers, there is scope to improve standards and definitions in this area. Ideally, different methods such as sleep diaries and questionnaires would be used concurrently with objective measures to ensure normal sleepers are identified, and descriptive information for control subjects would be reported. Here, we have devised working criteria and methods to be used for assessment of normal sleepers. This would help clarify the nature of the control group, in contrast to insomnia subjects and other patient groups

    Epidemiology, prehospital care and outcomes of patients arriving by ambulance with dyspnoea: An observational study

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    Background: This study aimed to determine epidemiology and outcome for patients presenting to emergency departments (ED) with shortness of breath who were transported by ambulance. Methods: This was a planned sub-study of a prospective, interrupted time series cohort study conducted at three time points in 2014 and which included consecutive adult patients presenting to the ED with dyspnoea as a main symptom. For this sub-study, additional inclusion criteria were presentation to an ED in Australia or New Zealand and transport by ambulance. The primary outcomes of interest are the epidemiology and outcome of these patients. Analysis was by descriptive statistics and comparisons of proportions. Results: One thousand seven patients met inclusion criteria. Median age was 74 years (IQR 61-68) and 46.1 % were male. There was a high rate of co-morbidity and chronic medication use. The most common ED diagnoses were lower respiratory tract infection (including pneumonia, 22.7 %), cardiac failure (20.5%) and exacerbation of chronic obstructive pulmonary disease (19.7 %). ED disposition was hospital admission (including ICU) for 76.4 %, ICU admission for 5.6 % and death in ED in 0.9 %. Overall in-hospital mortality among admitted patients was 6.5 %. Discussion: Patients transported by ambulance with shortness of breath make up a significant proportion of ambulance caseload and have high comorbidity and high hospital admission rate. In this study, >60 % were accounted for by patients with heart failure, lower respiratory tract infection or COPD, but there were a wide range of diagnoses. This has implications for service planning, models of care and paramedic training. Conclusion: This study shows that patients transported to hospital by ambulance with shortness of breath are a complex and seriously ill group with a broad range of diagnoses. Understanding the characteristics of these patients, the range of diagnoses and their outcome can help inform training and planning of services

    An integrated proteomic and transcriptomic signature of the failing right ventricle in monocrotaline induced pulmonary arterial hypertension in male rats

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    Aim: Pulmonary arterial hypertension (PAH) is an obstructive pulmonary vasculopathy that results in death from right ventricular failure (RVF). There is limited understanding of the molecular mechanisms of RVF in PAH. Methods: In a PAH-RVF model induced by injection of adult male rats with monocrotaline (MCT; 60 mg/kg), we performed mass spectrometry to identify proteins that change in the RV as a consequence of PAH induced RVF. Bioinformatic analysis was used to integrate our previously published RNA sequencing data from an independent cohort of PAH rats. Results: We identified 1,277 differentially regulated proteins in the RV of MCT rats compared to controls. Integration of MCT RV transcriptome and proteome data sets identified 410 targets that are concordantly regulated at the mRNA and protein levels. Functional analysis of these data revealed enriched functions, including mitochondrial metabolism, cellular respiration, and purine metabolism. We also prioritized 15 highly enriched protein:transcript pairs and confirmed their biological plausibility as contributors to RVF. We demonstrated an overlap of these differentially expressed pairs with data published by independent investigators using multiple PAH models, including the male SU5416-hypoxia model and several male rat strains. Conclusion: Multiomic integration provides a novel view of the molecular phenotype of RVF in PAH which includes dysregulation of pathways involving purine metabolism, mitochondrial function, inflammation, and fibrosis
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