291 research outputs found

    On the Link Between Central Black Holes, Bar Dynamics, and Dark Matter Halos in Spiral Galaxies

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    The discovery of a relationship between supermassive black hole (SMBH) mass and spiral arm pitch angle (P) is evidence that SMBHs are tied to the overall secular evolution of a galaxy. The discovery of SMBHs in late-type galaxies with little or no bulge suggests that an underlying correlation between the dark matter halo concentration and SMBH mass (MBH) exists, rather than between the bulge mass and MBH. In this paper we measure P using a two-dimensional fast fourier transform and estimate the bar pattern speeds of 40 barred spiral galaxies from the Carnegie-Irvine Galaxy Survey. The pattern speeds were derived by estimating the gravitational potentials of our galaxies from Ks-band images and using them to produce dynamical simulation models. The pattern speeds allow us to identify those galaxies with low central dark halo densities, or fast rotating bars, while P provides an estimate of MBH. We find that a wide range of MBH exists in galaxies with low central dark matter halo densities, which appears to support other theoretical results. We also find that galaxies with low central dark halo densities appear to follow more predictable trends in P versus de Vaucouleurs morphological type (T) and bar strength versus T than barred galaxies in general. The empirical relationship between MBH and total gravitational mass of a galaxy (Mtot) allows us to predict the minimum Mtot that will be observationally measured of our fast bar galaxies. These predictions will be investigated in a subsequent paper.Comment: 17 pages, 1 table, 11 figures, accepted for publication in MNRA

    A Trans-Theoretical Model for Farmers’ perceived Usefulness of Digital Risk Management Tools – A Case Study from Germany

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    Digital risk management tools (RMTs) are promising to help farmers manage risk. However, these recently developed tools are still unexplored and hardly used by farmers. This study is the first to investigate how German farmers perceive the usefulness of digital RMTs and which factors influence them. A novel modification of the trans-theoretical model was made to determine farmers’ perceived usefulness gradually. The regression results show that, on average, farmers perceive digital RMTs as potentially useful. Perceptions are positively influenced by a higher level of education, full-time employment on the farm, use of mobile devices and a higher perceived importance of digital tools. The study contributes to the literature by investigating the extent to which farmers are willing to accept the combination of digitisation and risk management. The results are of interest to policy makers involved in digital agriculture and to agricultural tool providers, as they offer first insights into farmers’ acceptance of digital RMTs. Researchers benefit from the successfully applied trans-theoretical model fitting

    Three, Two, One, Action: Incorporating Video Projects in Class Pedagogy

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    Ethnography is useful as a pedagogical tool because it uncovers layers of meaning, relies on inductive reasoning, and allows students to generate theory grounded in the empirical world. Likewise, using video project assignments encourages deep engagement, increases student recall of new knowledge, and links visual clues to memory. Video projects also encourage creativity and teach transferable technological skills. In this panel, I explore the pedagogical praxis of combining ethnographic methods, such as participant observation and interviewing, with video-making projects to encourage durable learning. Student co-presenters will show clips from their video projects and reflect on the impact of the assignment

    A Novel Benzodiazepine Compound Inhibits Yellow Fever Virus Infection by Specifically Targeting NS4B Protein

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    Although a highly effective vaccine is available, the number of yellow fever cases has increased over the past 2 decades, which highlights the pressing need for antiviral therapeutics. In a high-throughput screening campaign, we identified an acetic acid benzodiazepine (BDAA) compound which potently inhibits yellow fever virus (YFV). Interestingly, while treatment of YFV-infected cultures with 2 MBDAA reduced the virion production by greater than 2 logs, the compound was not active against 21 other viruses from 14 different viral families. Selection and genetic analysis of drug-resistant viruses revealed that replacement of the proline at amino acid 219 (P219) of the nonstructural protein 4B (NS4B) with serine, threonine, or alanine conferred YFV with resistance to BDAA without apparent loss of replication fitness in cultured mammalian cells. However, replacement of P219 with glycine conferred BDAA resistance with significant loss of replication ability. Bioinformatics analysis predicts that the P219 amino acid is localized at the endoplasmic reticulum lumen side of the fifth putative transmembrane domain of NS4B, and the mutation may render the viral protein incapable of interacting with BDAA. Our studies thus revealed an important role and the structural basis for the NS4B protein in supporting YFV replication. Moreover, in YFV-infected hamsters, oral administration of BDAA protected 90% of the animals from death, significantly reduced viral load by greater than 2 logs, and attenuated virus infection-induced liver injury and body weight loss. The encouraging preclinical results thus warrant further development of BDAA or its derivatives as antiviral agents to treat yellow fever

    Mucus-Inspired Self-Healing Hydrogels: A Protective Barrier for Cells against Viral Infection

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    Mucus is a dynamic biological hydrogel, composed primarily of the glycoprotein mucin, exhibits unique biophysical properties and forms a barrier protecting cells against a broad-spectrum of viruses. Here, this work develops a polyglycerol sulfate-based dendronized mucin-inspired copolymer (MICP-1) with ≈10% repeating units of activated disulfide as cross-linking sites. Cryo-electron microscopy (Cryo-EM) analysis of MICP-1 reveals an elongated single-chain fiber morphology. MICP-1 shows potential inhibitory activity against many viruses such as herpes simplex virus 1 (HSV-1) and SARS-CoV-2 (including variants such as Delta and Omicron). MICP-1 produces hydrogels with viscoelastic properties similar to healthy human sputum and with tuneable microstructures using linear and branched polyethylene glycol-thiol (PEG-thiol) as cross-linkers. Single particle tracking microrheology, electron paramagnetic resonance (EPR) and cryo-scanning electron microscopy (Cryo-SEM) are used to characterize the network structures. The synthesized hydrogels exhibit self-healing properties, along with viscoelastic properties that are tuneable through reduction. A transwell assay is used to investigate the hydrogel's protective properties against viral infection against HSV-1. Live-cell microscopy confirms that these hydrogels can protect underlying cells from infection by trapping the virus, due to both network morphology and anionic multivalent effects. Overall, this novel mucin-inspired copolymer generates mucus-mimetic hydrogels on a multi-gram scale. These hydrogels can be used as models for disulfide-rich airway mucus research, and as biomaterials

    Factors Associated With Access to HIV Testing and Primary Care Among Migrants Living in Europe: Cross-Sectional Survey

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    BACKGROUND: There is a heavy and disproportionate burden of human immunodeficiency virus (HIV) infection among migrant communities living in Europe. Despite this, the published evidence related to HIV testing, prevention, and treatment needs for migrants is sparse. OBJECTIVE: The aim of this study was to identify the factors associated with access to primary care and HIV testing among migrant groups living in Europe. METHODS: A Web-based survey (available in 14 languages) was open to all people aged 18 years and older, living outside their country of birth in the World Health Organization (WHO) European area. Community organizations in 9 countries promoted the survey to migrant groups, focusing on those at a higher risk of HIV (sub-Saharan Africans, Latin Americans, gay or bisexual men, and people who inject drugs). Multivariable analysis examined factors associated with access to primary care and previous history of an HIV test. RESULTS: In total, 559 women, 395 heterosexual men, and 674 gay or bisexual men were included in the analysis, and 68.1% (359/527) of women, 59.5% (220/371) of heterosexual men, and 89.6% (596/664) of gay or bisexual men had tested for HIV. Low perceived risk was the reason given for not testing by 62.3% (43/69) of gay or bisexual men and 83.3% (140/168) of women and heterosexual men who reported never having tested for HIV. Access to primary care was >60% in all groups. Access to primary care was strongly positively associated with living in Northern Europe compared with Southern Europe (women: adjusted odds ratio, aOR 34.56 [95% CI 11.58-101]; heterosexual men: aOR 6.93 [95% CI 2.49-19.35], and gay or bisexual men: aOR 2.53 [95% CI 1.23-5.19]), whereas those with temporary residency permits were less likely to have access to primary care (women: aOR 0.41 [95% CI 0.21-0.80] and heterosexual men: aOR 0.24 [95% CI 0.10-0.54] only). Women who had experience of forced sex (aOR 3.53 [95% CI 1.39-9.00]) or postmigration antenatal care (aOR 3.07 [95% CI 1.55-6.07]) were more likely to have tested for HIV as were heterosexual men who had access to primary care (aOR 3.13 [95% CI 1.58-6.13]) or reported "Good" health status (aOR 2.94 [95% CI 1.41-5.88]). CONCLUSIONS: Access to primary care is limited by structural determinants such as immigration and health care policy, which varies across Europe. For those migrants who can access primary care and other health services, missed opportunities for HIV testing remain a barrier to earlier testing and diagnosis for migrants in Europe. Clinicians should be aware of these potential structural barriers to HIV testing as well as low perception of HIV risk in migrant groups.This project received funding from the European Union’s Seventh Framework Programme for research, technological development, and demonstration under EuroCoord grant agreement number 260694. IF was funded by a Doctoral Research Fellowship from the National Institute for Health Research (NIHR). The views expressed in this paper are those of the authors and not necessarily those of the National Health Service (NHS), the National Institute for Health Research (NIHR), or the Department of Health. Additional funding was received from Gilead Sciences Europe Ltd; NIHR Clinical Research Network, the United Kingdom; Foundation for AIDS Research and Prevention in Spain (FISPSE) Project 361036/10; Consortium of Biomedical Research in Epidemiology and Public Health, Spain; Spanish HIV Research Network for Excellence (RD06/006 and RD12/0017/0018); Research and Development Fund, Public Health Service of Amsterdam; and the Swiss HIV Cohort Study (project #727), supported by the Swiss National Science Foundation (grant #148522) and by the Swiss HIV Cohort Study research foundation. No funder had any role in the study, writing of the manuscript, or decision to submit for publication.S

    Uptake and effects of orally ingested polystyrene microplastic particles in vitro and in vivo

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    Evidence exists that humans are exposed to plastic microparticles via diet. Data on intestinal particle uptake and health-related effects resulting from microplastic exposure are scarce. Aim of the study was to analyze the uptake and effects of microplastic particles in human in vitro systems and in rodents in vivo. The gastrointestinal uptake of microplastics was studied in vitro using the human intestinal epithelial cell line Caco-2 and thereof-derived co-cultures mimicking intestinal M-cells and goblet cells. Different sizes of spherical fluorescent polystyrene (PS) particles (1, 4 and 10 µm) were used to study particle uptake and transport. A 28-days in vivo feeding study was conducted to analyze transport at the intestinal epithelium and oxidative stress response as a potential consequence of microplastic exposure. Male reporter gene mice were treated three times per week by oral gavage with a mixture of 1 µm (4.55 × 107 particles), 4 µm (4.55 × 107 particles) and 10 µm (1.49 × 106 particles) microplastics at a volume of 10 mL/kg/bw. Effects of particles on macrophage polarization were investigated using the human cell line THP-1 to detect a possible impact on intestinal immune cells. Altogether, the results of the study demonstrate the cellular uptake of a minor fraction of particles. In vivo data show the absence of histologically detectable lesions and inflammatory responses. The particles did not interfere with the differentiation and activation of the human macrophage model. The present results suggest that oral exposure to PS microplastic particles under the chosen experimental conditions does not pose relevant acute health risks to mammals.</p

    Improved healing response in delayed unions of the tibia with low-intensity pulsed ultrasound: results of a randomized sham-controlled trial

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    <p>Abstract</p> <p>Background</p> <p>We compared the healing response of tibial delayed unions between subjects treated with low-intensity pulsed ultrasound (LIPUS) (n = 51) and subjects treated with a sham device (n = 50). Fracture age was ≥ 4 months in all cases. Study personnel and participants were blinded to random treatment assignment throughout the study.</p> <p>Methods</p> <p>This multi-center randomized sham-controlled trial was undertaken at six hospitals in Germany. Adult patients who had sustained a tibial shaft fracture that subsequently showed inadequate progress toward healing (i.e., delayed union) were enrolled and randomized to receive either LIPUS (Exogen 2000/2000+, Smith & Nephew GmbH, Schenefeld, Germany) or an identical nonoperative sham device. The daily treatment duration was 20 minutes, for a period of 16 weeks. Subjects randomly assigned to active treatment had the ultrasound pressure wave signal set at the following parameters: 1.5 MHz frequency, 1 kHz repetition rate, 200 μs pulse duration, 30 mW/cm<sup>2 </sup>spatial intensity. Progress toward healing was estimated from changes in bone mineral density (BMD) and gap area as determined from computed tomography scans. Intention-to-treat analysis was conducted using a multiple imputation methodology.</p> <p>Results</p> <p>Based on log-transformed data, mean improvement in BMD was 1.34 (90% confidence interval (CI) 1.14 to 1.57) times greater for LIPUS-treated subjects compared to sham (p = 0.002). A mean reduction in bone gap area also favored LIPUS treatment (p = 0.014).</p> <p>Conclusions</p> <p>These findings demonstrate significantly greater progress toward bone healing after LIPUS treatment compared to no LIPUS treatment in subjects with established delayed unions of the tibia.</p
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