30 research outputs found
Origin and ascent history of unusually crystal-rich alkaline basaltic magmas from the western Pannonian Basin
The last eruptions of the monogenetic Bakony-Balaton Highland Volcanic Field
(western Pannonian Basin, Hungary) produced unusually crystal- and xenolith-rich
alkaline basalts which are unique among the alkaline basalts of the Carpathian-
Pannonian Region. Similar alkaline basalts are only rarely known in other volcanic
fields of the world. These special basaltic magmas fed the eruptions of two closely
located volcanic centres: the BondorĂł-hegy and the FĂŒzes-tĂł scoria cone. Their
uncommon enrichment in diverse crystals produced unique rock textures and modified
original magma compositions (13.1-14.2 wt.% MgO, 459-657 ppm Cr, 455-564 ppm Ni
contents).
Detailed mineral-scale textural and chemical analyses revealed that the BondorĂł-hegy
and FĂŒzes-tĂł alkaline basaltic magmas have a complex ascent history, and that most
of their minerals (~30 vol.% of the rocks) represent foreign crystals derived from
different levels of the underlying lithosphere. The most abundant xenocrysts, olivine,
orthopyroxene, clinopyroxene and spinel, were incorporated from different regions and
rock types of the subcontinental lithospheric mantle. Megacrysts of clinopyroxene and
spinel could have originated from pegmatitic veins / sills which probably represent
magmas crystallized near the crust-mantle boundary. Green clinopyroxene xenocrysts
could have been derived from lower crustal mafic granulites. Minerals that crystallized
in situ from the alkaline basaltic melts (olivine with Cr-spinel inclusions, clinopyroxene,
plagioclase, Fe-Ti oxides) are only represented by microphenocrysts and overgrowths
on the foreign crystals. The vast amount of peridotitic (most common) and mafic
granulitic materials indicates a highly effective interaction between the ascending
magmas and wall rocks at lithospheric mantle and lower crustal levels. However,
fragments from the middle and upper crust are absent from the studied basalts,
suggesting a change in the style (and possibly rate) of magma ascent in the crust.
These xenocryst- and xenolith-rich basalts yield divers tools for estimating magma
ascent rate that is important for hazard forecasting in monogenetic volcanic fields.
According to the estimated ascent rates, the BondorĂł-hegy and FĂŒzes-tĂł alkaline
basaltic magmas could have reached the surface within hours to few days, similarly to
the estimates for other eruptive centres in the Pannonian Basin which were fed by
"normal" (crystal- and xenolith-poor) alkaline basalts
Golimumab induction and maintenance for moderate to severe ulcerative colitis: results from GO-COLITIS (Golimumab: a Phase 4, UK, open label, single arm study on its utilization and impact in ulcerative Colitis)
Objective GO-COLITIS aimed to measure the effectiveness of subcutaneous golimumab in tumour necrosis factor-α antagonistânaive patients with moderate to severe ulcerative colitis (UC) despite conventional treatment.
Design GO-COLITIS was an open label, single arm, phase 4 study with a pragmatic design which reflected UK clinical practice. Adult patients were eligible if diagnosed with UC â„3 months, partial Mayo score (PMS) 4â9. Patients received subcutaneous golimumab induction (200âmg initially and 100âmg at week 2) followed at week 6 by 50âmg or 100âmg (depending on weight) every 4 weeks until week 54 with a 12-week follow-up. Efficacy was measured by PMS at baseline, week 6, 30, 54 and 66. Health-related quality of life (HRQoL; Inflammatory Bowel Disease Questionnaire (IBDQ) and EuroQol Group 5 Dimensions Health Questionnaire (EQ-5D)) was assessed at baseline, week 6 and week 54. All safety adverse events (AEs) were recorded.
Results 207 patients were enrolled and 205 received golimumab (full analysis set (FAS)205). At week 6, 68.8% (95% CI 62.0% to 75.1%) and 38.5% (95% CI 31.8% to 45.6%) of patients were in response and remission, respectively, using PMS. At the end of the induction phase, 140/141 patients in clinical response continued into the maintenance phase (Maintenance FAS). Sustained clinical response through week 54 was achieved in 51/205 (24.9%) of the FAS205 population and 51/140 (36.4%) of the Maintenance FAS population. Statistically significant improvements from baseline to week 6 were observed for the IBDQ total score and for each IBDQ domain score (bowel symptoms, emotional function, systemic symptoms and social function), as well as the EQ-5D index score and associated visual analogue scale score (p<0.0001). Improvement of HRQoL was sustained through week 54. Serious AEs leading to treatment discontinuation occurred in 8.8% of patients.
Conclusion In this study measuring patient-reported outcomes in patients with moderate to severe UC, golimumab induced and maintained response as measured by PMS and significantly improved quality of life measures.
Trial registration number NCT02092285; 2013-004583-56
Pervasive melt percolation reactions in ultra-depleted refractory harzburgites at the Mid-Atlantic Ridge, 15° 20âČN : ODP Hole 1274A
Author Posting. © The Authors, 2006. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Contributions to Mineralogy and Petrology 153 (2007): 303-319, doi:10.1007/s00410-006-0148-6.ODP Leg 209 Site 1274 mantle peridotites are highly refractory in terms of lack of residual
clinopyroxene, olivine Mg# (up to 0.92) and spinel Cr# (~0.5), suggesting high degree of partial
melting (>20%). Detailed studies of their microstructures show that they have extensively
reacted with a pervading intergranular melt prior to cooling in the lithosphere, leading to
crystallization of olivine, clinopyroxene and spinel at the expense of orthopyroxene. The least
reacted harzburgites are too rich in orthopyroxene to be simple residues of low-pressure (spinel
field) partial melting. Cu-rich sulfides that precipitated with the clinopyroxenes indicate that
the intergranular melt was generated by no more than 12% melting of a MORB mantle or by
more extensive melting of a clinopyroxene-rich lithology. Rare olivine-rich lherzolitic domains,
characterized by relics of coarse clinopyroxenes intergrown with magmatic sulfides, support
the second interpretation. Further, coarse and intergranular clinopyroxenes are highly depleted
in REE, Zr and Ti. A two-stage partial melting/melt-rock reaction history is proposed, in which
initial mantle underwent depletion and refertilization after an earlier high pressure (garnet field)
melting event before upwelling and remelting beneath the present-day ridge. The ultra-depleted
compositions were acquired through melt re-equilibration with residual harzburgites.Funding for this
research was provided by Centre National de la Recherche Scientifique-Institut National des
Sciences de lâUnivers (Programme Dynamique et Evolution de la Terre Interne)
Outbreak of hepititis A in the injecting drug uiser and homeless populations in Bristol:control by targeted vaccination programme and possible parenteral tranmission
Basiliximab (anti-CD25) in combination with steriods may be an effective new treatment for steriod resistant ulcerative colitis
Lithospheric mantle beneath NE part of Bohemian Massif and its relation to overlying crust: new insights from Pilchowice xenolith suite, Sudetes, SW Poland
Origin of temporal - compositional variations during the eruption of Lake Purrumbete Maar, Newer Volcanics Province, southeastern Australia
Metasomatism and origin of glass in the lithospheric mantle xenoliths beneath Ain Temouchent area (North-West Algeria)
How partial melts of mafic lower crust affect ascending magmas at oceanic ridges
We present experiments showing that the lower oceanic crust should melt efficiently and quickly when heated by hot ascending magmas. Average plagioclaseâolivine and plagioclaseâaugite pairs from the lower crust at the Southwest Indian Ridge have meltâmineral saturation boundaries at 1,190 and 1,154°C, respectively, and melt rapidly (>0.01 mm/h) at 50°C or more above these temperatures. Melting experiments performed on olivineâplagioclase and augiteâplagioclase mineral pairs from actual oceanic lower crustal rock samples and under conditions applicable to a MOR setting (1,220â1,330°C, 1 atm, quartzâfayaliteâmagnetite oxygen buffer, 0.25â24 h) indicate that the resulting disequilibrium melts are linear mixes of the mineral compositions. The rates of melting are slower than the rate of heat-diffusion into a sample and are approximated as:
Ο=2.43Ă10(â26)Ăe0.004109ĂT(degC) (m/s1/2) for augite melted with plagioclase; Ο=3.47Ă10(â15)Ăe0.002041ĂT(degC)for plagioclase melted with augite; and Ο=1.79Ă10(â21)Ăe0.0032ĂT(degC) for plagioclase melted with olivine.
Our results indicate that great care must be taken in backward models using basalt chemistry alone to explore mantle-melting processes, assuming only crystallization and fractionation during ascent, as partial melts may mix with intruded hot magma