603 research outputs found
Epstein - Barr virus latent membrane protein 1 suppresses reporter activity through modulation of promyelocytic leukemia protein-nuclear bodies
The Epstein-Barr virus (EBV) encoded Latent Membrane Protein 1 (LMP1) has been shown to increase the expression of promyelocytic leukemia protein (PML) and the immunofluorescent intensity of promyelocytic leukemia nuclear bodies (PML NBs). PML NBs have been implicated in the modulation of transcription and the association of reporter plasmids with PML NBs has been implicated in repression of reporter activity. Additionally, repression of various reporters in the presence of LMP1 has been noted. This study demonstrates that LMP1 suppresses expression of reporter activity in a dose responsive manner and corresponds with the LMP1 induced increase in PML NB intensity. Disruption of PML NBs with arsenic trioxide or a PML siRNA restores reporter activity. These data offer an explanation for previously conflicting data on LMP1 signaling and calls attention to the possibility of false-positives and false-negatives when using reporter assays as a research tool in cells expressing LMP1
Reflecting on the Design and Implementation Issues of Virtual Environments
We present a candid reflection on the issues surrounding virtual environment design and implementation (VEDI) in order to: (1) motivate the topic as a research-worthy undertaking, and (2) attempt a comprehensive listing of impeding VEDI issues so they can be addressed. In order to structure this reflection, an idealized model of VEDI is presented. This model, investigated using mixed methods, resulted in 67 distinct issues along the model\u27s transitions and pathways. These were clustered into 11 themes and used to support five VEDI research challenges
Eruptive modes and hiatus of volcanism at West Mata seamount, NE Lau basin : 1996–2012
Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 15 (2014): 4093–4115, doi:10.1002/2014GC005387.We present multiple lines of evidence for years to decade-long changes in the location and character of volcanic activity at West Mata seamount in the NE Lau basin over a 16 year period, and a hiatus in summit eruptions from early 2011 to at least September 2012. Boninite lava and pyroclasts were observed erupting from its summit in 2009, and hydroacoustic data from a succession of hydrophones moored nearby show near-continuous eruptive activity from January 2009 to early 2011. Successive differencing of seven multibeam bathymetric surveys of the volcano made in the 1996–2012 period reveals a pattern of extended constructional volcanism on the summit and northwest flank punctuated by eruptions along the volcano's WSW rift zone (WSWRZ). Away from the summit, the volumetrically largest eruption during the observational period occurred between May 2010 and November 2011 at ∼2920 m depth near the base of the WSWRZ. The (nearly) equally long ENE rift zone did not experience any volcanic activity during the 1996–2012 period. The cessation of summit volcanism recorded on the moored hydrophone was accompanied or followed by the formation of a small summit crater and a landslide on the eastern flank. Water column sensors, analysis of gas samples in the overlying hydrothermal plume and dives with a remotely operated vehicle in September 2012 confirmed that the summit eruption had ceased. Based on the historical eruption rates calculated using the bathymetric differencing technique, the volcano could be as young as several thousand years.Support for R.W.E. during this study was by internal NOAA funding to the NOAA Vents Program (now Earth-Ocean Interactions Program). The NSF Ridge 2000 and MARGINS programs played a major role in the planning and justification for the 2009 rapid response proposal that funded the May 2009 expedition. MBARI provided support and outstanding postprocessing of the multibeam bathymetry from the D. Allan B. AUV multibeam sonar used in this study. NSF also provided major funding for the 2009 expedition (OCE930025 and OCE-0934660 to JAR) and for the 210Po-210Pb radiometric dating (OCE-0929881 and for the 210Po-210Pb radiometric dating (OCE-0929881 to KHR)). The NOAA Office of Exploration and Research provided major funding for the 2009 and 2012 field programs.2015-04-3
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Imaging of CO₂ bubble plumes above an erupting submarine volcano, NW Rota-1, Mariana Arc
NW Rota-1 is a submarine volcano in the Mariana volcanic arc located ~100 km north of Guam.
Underwater explosive eruptions driven by magmatic gases were first witnessed there in 2004 and continued
until at least 2010. During a March 2010 expedition, visual observations documented continuous but
variable eruptive activity at multiple vents at ~560 m depth. Some vents released CO₂ bubbles passively
and continuously, while others released CO₂ during stronger but intermittent explosive bursts. Plumes of
CO₂ bubbles in the water column over the volcano were imaged by an EM122 (12 kHz) multibeam sonar
system. Throughout the 2010 expedition numerous passes were made over the eruptive vents with the ship
to document the temporal variability of the bubble plumes and relate them to the eruptive activity on the
seafloor, as recorded by an in situ hydrophone and visual observations. Analysis of the EM122 midwater
data set shows: (1) bubble plumes were present on every pass over the summit and they rose 200-400 m
above the vents but dissolved before they reached the ocean surface, (2) bubble plume deflection direction
and distance correlate well with ocean current direction and velocity determined from the ship’s acoustic
doppler current profiler, (3) bubble plume heights and volumes were variable over time and correlate with
eruptive intensity as measured by the in situ hydrophone. This study shows that midwater multibeam sonar
data can be used to characterize the level of eruptive activity and its temporal variability at a shallow submarine
volcano with robust CO₂ output.Keywords: multibeam sonar, carbon dioxide degassing, submarine eruption, seamoun
A Recent Volcanic Eruption Discovered on the Central Mariana Back-Arc Spreading Center
Submarine volcanic eruptions are difficult to detect because they are hidden from view at the bottom of the ocean and far from land-based sensors. However, most of Earth’s volcanic activity is in the oceans along tectonic plate boundaries, and modern tools of oceanography now allow us to find and study recent eruptions in the deep sea. The first known historical eruption on the Mariana back-arc spreading center was discovered in December 2015 during exploration of the southern back-arc for new hydrothermal vent sites. A water-column survey along the axis of the back-arc showed hydrothermal plumes over the site characterized by low particle concentrations and relatively high reduced chemical anomalies. A dive with the autonomous underwater vehicle Sentry collected high-resolution (1 m) multibeam sonar bathymetry over the site, followed by a near-bottom photographic survey of a smaller area. The photo survey revealed the presence of a pristine, dark, glassy lava flow on the seafloor with no sediment cover. Venting of milky hydrothermal fluid indicated that the lava flow was still warm and therefore very young. A comparison of multibeam sonar bathymetry collected by R/V Falkor in December 2015, to the most recent previous survey of the area by R/V Melville in February 2013, revealed large depth changes in the same area, effectively bracketing the timing of the eruption within a window of less than 3 years. The bathymetric comparison shows the eruption produced a string of lava flows with maximum thicknesses of 40–138 m along a distance of 7.3 km (from latitude 15∘22.3′ to 15∘26.3′N) between depths of 4050–4450 m bsl (meters below sea level), making this the deepest known historical submarine volcanic eruption on Earth. The cross-axis width of the lava flows is 200–800 m. The Sentry bathymetry shows that the new lava flows are constructed of steep-sided hummocky pillow mounds and are surrounded by older flows with similar morphology. In April and December 2016, two dives were made on the new lava flows by remotely operated vehicles Deep Discoverer and SuBastian. The pillow lavas have many small glassy buds on the steep flanks of the mounds, locally thick accumulations of hydrothermal sediment near the tops of mounds, and small cones of radiating pillows at their summits. The 2015–2016 observations show a rapidly declining hydrothermal system on the lava flows, suggesting that the eruption had occurred only months before its discovery in December 2015. The morphology of the pillow lavas is similar to other historical eruption sites, so the greater depth and ambient pressure of this site had no apparent effect on the processes of lava extrusion and emplacement. This study reveals that some segments of the Mariana back-arc have active magmatic systems despite the relatively low spreading rate, and that other eruptions are possible in the near future
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Eruptive modes and hiatus of volcanism at West Mata seamount, NE Lau basin: 1996–2012
We present multiple lines of evidence for years to decade-long changes in the location and
character of volcanic activity at West Mata seamount in the NE Lau basin over a 16 year period, and a hiatus
in summit eruptions from early 2011 to at least September 2012. Boninite lava and pyroclasts were
observed erupting from its summit in 2009, and hydroacoustic data from a succession of hydrophones
moored nearby show near-continuous eruptive activity from January 2009 to early 2011. Successive differencing
of seven multibeam bathymetric surveys of the volcano made in the 1996–2012 period reveals a pattern
of extended constructional volcanism on the summit and northwest flank punctuated by eruptions
along the volcano’s WSW rift zone (WSWRZ). Away from the summit, the volumetrically largest eruption during
the observational period occurred between May 2010 and November 2011 at ~2920 m depth near the
base of the WSWRZ. The (nearly) equally long ENE rift zone did not experience any volcanic activity during
the 1996–2012 period. The cessation of summit volcanism recorded on the moored hydrophone was
accompanied or followed by the formation of a small summit crater and a landslide on the eastern flank.
Water column sensors, analysis of gas samples in the overlying hydrothermal plume and dives with a
remotely operated vehicle in September 2012 confirmed that the summit eruption had ceased. Based on
the historical eruption rates calculated using the bathymetric differencing technique, the volcano could be
as young as several thousand years.Keywords: Multibeam, Volcano, Submarine, Lau, Seamount, Eruptio
A monoclonal antibody against kininogen reduces inflammation in the HLA-B27 transgenic rat
The human leukocyte antigen B27 (HLA-B27) transgenic rat is a model of human inflammatory bowel disease, rheumatoid arthritis and psoriasis. Studies of chronic inflammation in other rat models have demonstrated activation of the kallikrein–kinin system as well as modulation by a plasma kallikrein inhibitor initiated before the onset of clinicopathologic changes or a deficiency in high-molecular-mass kininogen. Here we study the effects of monoclonal antibody C11C1, an antibody against high-molecular-mass kininogen that inhibits the binding of high-molecular-mass kininogen to leukocytes and endothelial cells in the HLA-B27 rat, which was administered after the onset of the inflammatory changes. Thrice-weekly intraperitoneal injections of monoclonal antibody C11C1 or isotype IgG(1 )were given to male 23-week-old rats for 16 days. Stool character as a measure of intestinal inflammation, and the rear limbs for clinical signs of arthritis (tarsal joint swelling and erythema) were scored daily. The animals were killed and the histology sections were assigned a numerical score for colonic inflammation, synovitis, and cartilage damage. Administration of monoclonal C11C1 rapidly decreased the clinical scores of pre-existing inflammatory bowel disease (P < 0.005) and arthritis (P < 0.001). Histological analyses confirmed significant reductions in colonic lesions (P = 0.004) and synovitis (P = 0.009). Decreased concentrations of plasma prekallikrein and high-molecular-mass kininogen were found, providing evidence of activation of the kallikrein–kinin system. The levels of these biomarkers were reversed by monoclonal antibody C11C1, which may have therapeutic potential in human inflammatory bowel disease and arthritis
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