1,285 research outputs found

    Mesopore etching under supercritical conditions – A shortcut to hierarchically porous silica monoliths

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    Hierarchically porous silica monoliths are obtained in the two-step Nakanishi process, where formation of a macro microporous silica gel is followed by widening micropores to mesopores through surface etching. The latter step is carried out through hydrothermal treatment of the gel in alkaline solution and necessitates a lengthy solvent exchange of the aqueous pore fluid before the ripened gel can be dried and calcined into a mechanically stable macro mesoporous monolith. We show that using an ethanol water (95.6/4.4, v/v) azeotrope as supercritical fluid for mesopore etching eliminates the solvent exchange, ripening, and drying steps of the classic route and delivers silica monoliths that can withstand fast heating rates for calcination. The proposed shortcut decreases the overall preparation time from ca. one week to ca. one day. Porosity data show that the alkaline conditions for mesopore etching are crucial to obtain crack-free samples with a narrow mesopore size distribution. Physical reconstruction of selected samples by confocal laser scanning microscopy and subsequent morphological analysis confirms that monoliths prepared via the proposed shortcut possess the high homogeneity of silica skeleton and macropore space that is desirable in adsorbents for flow-through applications

    Early exposure of bay scallops (Argopecten irradians) to high CO2 causes a decrease in larval shell growth

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    © The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS ONE 8 (2013): e61065, doi:10.1371/journal.pone.0061065.Ocean acidification, characterized by elevated pCO2 and the associated decreases in seawater pH and calcium carbonate saturation state (Ω), has a variable impact on the growth and survival of marine invertebrates. Larval stages are thought to be particularly vulnerable to environmental stressors, and negative impacts of ocean acidification have been seen on fertilization as well as on embryonic, larval, and juvenile development and growth of bivalve molluscs. We investigated the effects of high CO2 exposure (resulting in pH = 7.39, Ωar = 0.74) on the larvae of the bay scallop Argopecten irradians from 12 h to 7 d old, including a switch from high CO2 to ambient CO2 conditions (pH = 7.93, Ωar = 2.26) after 3 d, to assess the possibility of persistent effects of early exposure. The survival of larvae in the high CO2 treatment was consistently lower than the survival of larvae in ambient conditions, and was already significantly lower at 1 d. Likewise, the shell length of larvae in the high CO2 treatment was significantly smaller than larvae in the ambient conditions throughout the experiment and by 7 d, was reduced by 11.5%. This study also demonstrates that the size effects of short-term exposure to high CO2 are still detectable after 7 d of larval development; the shells of larvae exposed to high CO2 for the first 3 d of development and subsequently exposed to ambient CO2 were not significantly different in size at 3 and 7 d than the shells of larvae exposed to high CO2 throughout the experiment.This work was funded by a Woods Hole Oceanographic Institution Interdisciplinary Award to Mullineaux & McCorkle; and awards to Mullineaux & White, to McCorkle, and to Cohen & McCorkle through NOAA (National Oceanic and Admosphereic Administration) Sea Grant #NA10OAR4170083. White was funded through a National Defense Science and Engineering Graduate Fellowship through the American Society for Engineering Education

    Top Predators Negate the Effect of Mesopredators on Prey Physiology

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    Predation theory and empirical evidence suggest that top predators benefit the survival of resource prey through the suppression of mesopredators. However, whether such behavioural suppression can also affect the physiology of resource prey has yet to be examined. Using a three‐tier reef fish food web and intermittent‐flow respirometry, our study examined changes in the metabolic rate of resource prey exposed to combinations of mesopredator and top predator cues. Under experimental conditions, the mesopredator (dottyback, Pseudochromis fuscus ) continuously foraged and attacked resource prey (juveniles of the damselfish Pomacentrus amboinensis ) triggering an increase in prey O2 uptake by 38 ± 12·9% (mean ± SE). The visual stimulus of a top predator (coral trout, Plectropomus leopardus ) restricted the foraging activity of the mesopredator, indirectly allowing resource prey to minimize stress and maintain routine O2 uptake. Although not as strong as the effect of the top predator, the sight of a large non‐predator species (thicklip wrasse, Hemigymnus melapterus ) also reduced the impact of the mesopredator on prey metabolic rate. We conclude that lower trophic‐level species can benefit physiologically from the presence of top predators through the behavioural suppression that top predators impose on mesopredators. By minimizing the energy spent on mesopredator avoidance and the associated stress response to mesopredator attacks, prey may be able to invest more energy in foraging and growth, highlighting the importance of the indirect, non‐consumptive effects of top predators in marine food webs

    Expectations of Success as a Predictor of Negative Symptom Reduction over 18 months in Individuals with Schizophrenia

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    Negative symptoms are often enduring and lead to poor functional outcomes in individuals with schizophrenia. The cognitive model of negative symptoms proposes that low expectancies of success contribute to the development and maintenance of negative symptoms; however, longitudinal investigations assessing these beliefs and negative symptoms are needed. The current study examined whether an individual’s baseline expectancies of success – one’s beliefs about future success and goal attainment – predicted negative symptoms reduction over 18 months in individuals with schizophrenia-spectrum disorders (n=118). Data were collected at baseline, 9 months, and 18 months as part of a randomized controlled trial of Illness Management and Recovery. A mixed effects regression analysis revealed a significant reduction in negative symptoms over time, with a significant interaction effect between time and baseline expectancies of success. After controlling for baseline negative symptoms, demographic variables, and treatment conditions, those with high and moderate baseline expectancies of success evidenced a significant reduction in negative symptoms at 18 months, while those with low baseline expectancies of success did not evidence reduced negative symptoms. Findings support the cognitive model of negative symptoms and suggest that expectancies of success may be a useful treatment target for interventions aimed at reducing negative symptoms

    The cognitive and emotional effects of cognitive bias modification in interpretations in behaviorally inhibited youth

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    Cognitive bias modification (CBM) procedures follow from the view that interpretive biases play an important role in the development and maintenance of anxiety. As such, understanding the link between interpretive biases and anxiety in youth at risk for anxiety (e.g., behaviorally inhibited children) could elucidate the mechanisms involved in the development of pediatric anxiety. However, to date, the majority of CBM-I work only studies adult populations. The present article presents the results of a CBM study examining effects of positive interpretive bias modification on mood, stress vulnerability, and threat-related attention bias in a group of behaviorally inhibited children (n = 45). Despite successful modification of interpretive bias in the at-risk youth, minimal effects on stress vulnerability or threat-related attention bias were found. The current findings highlight the need for continued research on cognitive biases in anxiety

    The lay health worker-patient relationship in promoting pulmonary rehabilitation (PR) in COPD: What makes it work?

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    Lay health workers (LHWs) can improve access to services and adherence to treatment, as well as promoting self-care and prevention. Their effect in promoting uptake and adherence in pulmonary rehabilitation (PR) for chronic obstructive pulmonary disease (COPD) has not been tested. PR is the most effective treatment for the symptoms and disability of COPD, but this effectiveness is undermined by poor rates of completion. Trained LHWs with COPD, who also have first-hand experience of PR, are well placed to help overcome the documented barriers to its completion. The relationship between LHWs and patients may be one of the keys to their effectiveness but it has been little explored. Semi-structured qualitative interviews were used with the aim of examining the LHW-patient partnership in a feasibility study of trained PR-experienced LHWs used to support COPD patients referred to PR. Twelve volunteers with COPD who completed LHW training supported 66 patients referred for PR. All 12 of these LHWs gave end-of-study interviews, 21 COPD patients supported by LHWs were also interviewed. Patients reported that the LHWs were keen to share their experiences of PR, and that this had a positive impact. The enthusiasm of the LHWs for PR was striking. The common bond between LHWs and patients of having COPD together with the LHWs positive, first-hand experience of PR were dominant and recurring themes in their relationship.This article presents independent research funded by the NIHR under its Research for Patient Benefit (RfPB) Programme (Grant Reference Number PB-PG0214-30052). SL receives additional funding from the South African Medical Research Council. SJCT was supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care (CLAHRC) North Thames at Bart’s Health NHS Trust

    Core pathway mutations induce de-differentiation of murine astrocytes into glioblastoma stem cells that are sensitive to radiation but resistant to temozolomide

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    Glioma stem cells (GSCs) from human glioblastomas (GBMs) are resistant to radiation and chemotherapy and may drive recurrence. Treatment efficacy may depend on GSCs, expression of DNA repair enzymes such as methylguanine methyltransferase (MGMT), or transcriptome subtype

    Utility of a next generation framework for assessment of genomic damage: A case study using the industrial chemical benzene

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    We recently published a next generation framework for assessing the risk of genomic damage via exposure to chemical substances. The framework entails a systematic approach with the aim to quantify risk levels for substances that induce genomic damage contributing to human adverse health outcomes. Here, we evaluated the utility of the framework for assessing the risk for industrial chemicals, using the case of benzene. Benzene is a well‐studied substance that is generally considered a genotoxic carcinogen and is known to cause leukemia. The case study limits its focus on occupational and general population health as it relates to benzene exposure. Using the framework as guidance, available data on benzene considered relevant for assessment of genetic damage were collected. Based on these data, we were able to conduct quantitative analyses for relevant data sets to estimate acceptable exposure levels and to characterize the risk of genetic damage. Key observations include the need for robust exposure assessments, the importance of information on toxicokinetic properties, and the benefits of cheminformatics. The framework points to the need for further improvement on understanding of the mechanism(s) of action involved, which would also provide support for the use of targeted tests rather than a prescribed set of assays. Overall, this case study demonstrates the utility of the next generation framework to quantitatively model human risk on the basis of genetic damage, thereby enabling a new, innovative risk assessment concept. Environ. Mol. Mutagen. 61:94–113, 2020. © 2019 The Authors. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.JRC.F.3-Chemicals Safety and Alternative Method

    New range limits of the sun-tailed monkey, Cercopithecus solatus, in Central Gabon

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    Cercopithecus solatus is a recently discovered monkey endemic to Gabon, present in parts of the Lopé National Park and the Forêt des Abeilles in the center of the country. It is listed as Vulnerable on the IUCN Red List (2010) due to its restricted extent of occurrence and continuing decline in population caused by high hunting pressure. All known field observations of this species are compiled here. Data collected since 1999 show that C. solatus occurs further to the south, east, and west than was previously known, and that its extent of occurrence almost certainly includes three national parks, rather than one

    Evidence of interspecific plasmid uptake by pathogenic strains of Klebsiella isolated from microplastic pollution on public beaches

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    Microplastic beads are becoming a common feature on beaches, and there is increasing evidence that such microplastics can become colonised by potential human pathogens. However, whether the concentrations and pathogenicity of these pathogens pose a public health risk are still unclear. Therefore, the aim of this study was to determine realistic environmental concentrations of potential pathogens colonising microplastic beads, and quantify the expression of virulence and antimicrobial resistance genes (ARGs). Microplastic beads were collected from beaches and a culture-dependent approach was used to determine the concentrations of seven target bacteria (Campylobacter spp.; E. coli; intestinal enterococci; Klebsiella spp.; Pseudomonas aeruginosa; Salmonella spp.; Vibrio spp.). All seven target bacteria were detected without the need for a pre-enrichment step; urban sites had higher bacterial concentrations, whilst polymer type had no influence on bacterial concentrations. Klebsiella was the most abundant target bacteria and possessed virulence and ARGs, some of which were present on plasmids from other species, and showed pathogenicity in a Galleria melonella infection model. Our findings demonstrate how pathogen colonised microplastic beads can pose a heightened public health risk at the beach, and highlights the urgency for improved monitoring and enforcement of regulations on the release of microplastics into the environment
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