89 research outputs found

    Monitoring Observations of the Jupiter-Family Comet 17P/Holmes during 2014 Perihelion Passage

    Full text link
    We performed a monitoring observation of a Jupiter-Family comet, 17P/Holmes, during its 2014 perihelion passage to investigate its secular change in activity. The comet has drawn the attention of astronomers since its historic outburst in 2007, and this occasion was its first perihelion passage since then. We analyzed the obtained data using aperture photometry package and derived the Afrho parameter, a proxy for the dust production rate. We found that Afrho showed asymmetric properties with respect to the perihelion passage: it increased moderately from 100 cm at the heliocentric distance r_h=2.6-3.1 AU to a maximal value of 185 cm at r_h = 2.2 AU (near the perihelion) during the inbound orbit, while dropping rapidly to 35 cm at r_h = 3.2 AU during the outbound orbit. We applied a model for characterizing dust production rates as a function of r_h and found that the fractional active area of the cometary nucleus had dropped from 20%-40% in 2008-2011 (around the aphelion) to 0.1%-0.3% in 2014-2015 (around the perihelion). This result suggests that a dust mantle would have developed rapidly in only one orbital revolution around the sun. Although a minor eruption was observed on UT 2015 January 26 at r_h = 3.0 AU, the areas excavated by the 2007 outburst would be covered with a layer of dust (<~ 10 cm depth) which would be enough to insulate the subsurface ice and to keep the nucleus in a state of low activity.Comment: 25 pages, 6 figures, 2 tables, ApJ accepted on December 29, 201

    Potential Nematode Alarm Pheromone Induces Acute Avoidance in Caenorhabditis elegans

    Get PDF
    It is crucial for animal survival to detect dangers such as predators. A good indicator of dangers is injury of conspecifics. Here we show that fluids released from injured conspecifics invoke acute avoidance in both free-living and parasitic nematodes. Caenorhabditis elegans avoids extracts from closely related nematode species but not fruit fly larvae. The worm extracts have no impact on animal lifespan, suggesting that the worm extract may function as an alarm instead of inflicting physical harm. Avoidance of the worm extract requires the function of a cGMP signaling pathway that includes the cGMP-gated channel TAX-2/TAX-4 in the amphid sensory neurons ASI and ASK. Genetic evidence indicates that the avoidance behavior is modulated by the neurotransmitters GABA and serotonin, two common targets of anxiolytic drugs. Together, these data support a model that nematodes use a nematode-specific alarm pheromone to detect conspecific injury

    Bronchial and non-bronchial systemic artery embolization with transradial access in patients with hemoptysis

    Get PDF
    PURPOSEWe aimed to determine the safety and feasibility of transradial access (TRA) in bronchial artery and non-bronchial systemic artery (NBSA) embolization in patients with non-massive hemoptysis.METHODSThis retrospective study was approved by the Institutional Review Board. Among the 300 patients treated for hemoptysis with bronchial artery and NBSA embolization between April 2018 and July 2019, 19 procedures in 19 patients were conducted by TRA and were retrospectively analyzed. TRA was considered when the bronchial artery or NBSA originated from the arch vessel or its tributaries. The exclusion criteria of TRA included Barbeau C or D waveform and a radial artery diameter of less than 1.8 mm on ultrasound. TRA was also avoided in cases of the high-origin bronchial artery (i.e., T4 or higher level of the aorta). The hemoptysis-free time was estimated using the Kaplan–Meier method.RESULTSThe technical success (i.e., embolization of all target artery with TRA) rate was 94.7% (18 out of 19 patients). In terms of the target arteries, embolization with TRA was technically successful in treating 47 out of 48 arteries (97.9%). The 1-month and 6-month hemoptysis-free rates were 89.5% (17/19) and 73.7% (14/19), respectively. The only adverse event was iatrogenic dissection of the bronchial artery with little clinical significance in 1 patient. No access site complications were identified on post-procedure day 1 ultrasonography.CONCLUSIONWith proper patient selection, TRA offers a safe and effective approach to embolize the bronchial arteries and NBSAs in patients with hemoptysis

    Aberrant host immune response induced by highly virulent PRRSV identified by digital gene expression tag profiling

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>There was a large scale outbreak of the highly pathogenic porcine reproductive and respiratory syndrome (PRRS) in China and Vietnam during 2006 and 2007 that resulted in unusually high morbidity and mortality among pigs of all ages. The mechanisms underlying the molecular pathogenesis of the highly virulent PRRS virus (H-PRRSV) remains unknown. Therefore, the relationship between pulmonary gene expression profiles after H-PRRSV infection and infection pathology were analyzed in this study using high-throughput deep sequencing and histopathology.</p> <p>Results</p> <p>H-PRRSV infection resulted in severe lung pathology. The results indicate that aberrant host innate immune responses to H-PRRSV and induction of an anti-apoptotic state could be responsible for the aggressive replication and dissemination of H-PRRSV. Prolific rapid replication of H-PRRSV could have triggered aberrant sustained expression of pro-inflammatory cytokines and chemokines leading to a markedly robust inflammatory response compounded by significant cell death and increased oxidative damage. The end result was severe tissue damage and high pathogenicity.</p> <p>Conclusions</p> <p>The systems analysis utilized in this study provides a comprehensive basis for better understanding the pathogenesis of H-PRRSV. Furthermore, it allows the genetic components involved in H-PRRSV resistance/susceptibility in swine populations to be identified.</p

    Global assessment of marine plastic exposure risk for oceanic birds

    Get PDF
    Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species

    Robust estimation of bacterial cell count from optical density

    Get PDF
    Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

    Global assessment of marine plastic exposure risk for oceanic birds

    Get PDF
    Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species

    Schizophrenia Pathophysiology a Product of NMDA Receptor and GABA Interneuron Dysregulation in the Prefrontal Cortex and Hippocampus

    No full text
    Schizophrenia is noted for its complexity, owing to its heterogeneous expression and encompassment of symptoms that are seemingly opposite in nature. The current therapeutic efficacy against schizophrenia is limited, necessitating the translation of more descriptive biochemical mechanisms into the clinical scene. One converging mechanism, which implicates the dysregulation of excitatory N-methyl-D-aspartate (NMDA) receptors and inhibitory γ-Aminobutyric acid (GABA) interneurons, provides a complete biochemical mechanism that accounts for the diverse symptomatology of schizophrenia. Specifically, the dysfunction of NMDA receptors on GABA interneurons alters inhibitory and excitatory activity differentially in the prefrontal cortex (PFC) and hippocampus, giving rise to divergent abnormalities. Evidence from various studies suggests that NMDA-GABA interneuron dysfunction serves as a one of the primary contributors of schizophrenic pathophysiology and is possibly implicated in its pathogenesis, indicating the mechanism\u27s significant clinical potential
    corecore