1,730 research outputs found
Role of syn-eruptive plagioclase disequilibrium crystallization in basaltic magma ascent dynamics
The role of syn-eruptive vesiculation on explosive basaltic activity at Mt. Etna, Italy
We investigated the dynamics of explosive activity at Mt. Etna between 31 August and 15 December 2006 by combining vesicle studies in the erupted products with measurements of the gas composition at the active, summit crater. The analysed scoria clasts present large, connected vesicles with complex shapes and smaller, isolated, spherical vesicles, the content of which increases in scoriae from the most explosive events. Gas geochemistry reports CO2/SO2 and SO2/HCl ratios supporting a deep-derived gas phase for fire-fountain activity. By integrating results from scoria vesiculation and gas analysis we find that the highest energy episodes of Mt. Etna activity in 2006 were driven by a previously accumulated CO2-rich gas phase but we highlight the lesser role of syn-eruptive vesicle nucleation driven by water exsolution during ascent. We conclude that syn-eruptive vesiculation is a common process in Etnean magmas that may promote a deeper conduit magma fragmentation and increase ash formation
New insights into volcanic processes at Stromboli from Cerberus, a remote-controlled open-path FTIR scanner system
The ordinary, low intensity, activity of Stromboli volcano is sporadically interrupted by more energetic events termed, depending on their intensity, “major explosions” and “paroxysms”. These short-lived energetic episodes represent a potential risk to visitors to the highly accessible summit of Stromboli. Observations made at Stromboli over the last decade have shown that the composition of gas emitted from the summit craters may change prior to such explosions, allowing the possibility that such changes may be used to forecast these potentially dangerous events.
In 2008 we installed a novel, remote-controlled, open-path FTIR scanning system called Cerberus at the summit of Stromboli, with the objective of measuring gas compositions from individual vents within the summit crater terrace of the volcano with high temporal resolution and for extended periods. In this work we report the first results from the Cerberus system, collected in August-September 2009, November 2009 and May-June 2010.
We find significant, fairly consistent, intra-crater variability for CO2/SO2 and H2O/CO2 ratios, and relatively homogeneous SO2/HCl ratios. In general, the southwest crater is richest in CO2, and the northeast crater poorest, while the central crater is richest in H2O. It thus appears that during the measurement period the southwest crater had a somewhat more direct connection to a primary, deep degassing system; whilst the central and northeast craters reflect a slightly more secondary degassing nature, with a supplementary, shallow H2O source for the central crater, probably related to puffing activity. Such water-rich emissions from the central crater can account for the lower crystal content of its eruption products, and emphasise the role of continual magma supply to the shallowest levels of Stromboli's plumbing system.
Our observations of heterogeneous crater gas emissions and high H2O/CO2 ratios do not agree with models of CO2-flushing, and we show that simple depressurisation during magma ascent to the surface is a more likely model for H2O loss at Stromboli. We highlight that alternative explanations other than CO2 flushing are required to explain distributions of H2O and CO2 amounts dissolved in melt inclusions.
We detected fairly systematic increases in CO2/SO2 ratio some weeks prior to major explosions, and some evidence of a decrease in this ratio in the days immediately preceding the explosions, with periods of low, stable CO2/SO2 ratios between explosions otherwise. Our measurements, therefore, confirm the medium term (~ weeks) precursory increases previously observed with MultiGas instruments, and, in addition, reveal new, short-term precursory decreases in CO2/SO2 ratios. immediately prior to the major explosions. Such patterns, if shown to be systematic, may be of great utility for hazard management at Stromboli's summit.
Our results suggest that intra-crater CO2/SO2 variability may produce short-term peaks and troughs in CO2/SO2 time series measured with in-situ MultiGas instruments, due simply to variations in wind direction
The role of syn-eruptive vesiculation on explosive basaltic activity at Mt. Etna, Italy
We investigated the dynamics of explosive activity at Mt. Etna between 31 August and 14 December 2006 by combining vesicle studies in the erupted products with measurements of the gas composition at the active, summit crater. The analysed scoria clasts present large, connected vesicles with complex shapes and smaller, isolated, spherical vesicles, the content of which increases in scoriae from the most explosive events. Gas geochemistry reports CO2/SO2 and SO2/HCl ratios supporting a deep-derived gas phase for fire-fountain activity. By integrating results from scoria vesiculation and gas analysis we find that the highest energy episodes of Mt. Etna activity in 2006 were driven by a previously accumulated CO2-rich gas phase but we highlight the lesser role of syn-eruptive vesicle nucleation driven by water exsolution during ascent. We conclude that syn-eruptive vesiculation is a common process in Etnean magmas that may promote a deeper conduit magma fragmentation and increase ash formatio
Infrared spectral characterisation of some volcanic rocks on Mt. Etna with in-situ instruments, June 2007
Determining the Effect of Varying Magmatic Volatile Content on Lunar Magma Ascent Dynamics
From Wiley via Jisc Publications RouterHistory: received 2021-05-05, rev-recd 2021-09-03, accepted 2021-10-01, pub-electronic 2021-10-29, pub-print 2021-11Article version: VoRPublication status: PublishedFunder: UKRI, Science and Technology Facilities Council (STFC); Id: http://dx.doi.org/10.13039/501100000271; Grant(s): ST/S505560/1, ST/M001253/1Funder: Royal Society; Id: http://dx.doi.org/10.13039/501100000288; Grant(s): URF\R\201009Funder: Leverhulme Trust; Id: http://dx.doi.org/10.13039/501100000275; Grant(s): RPG‐2019‐222)Funder: RCUK NERC DisEqm project, Natural Environment Research Council (NERC); Id: http://dx.doi.org/10.13039/501100000270; Grant(s): NE/N018575/1Abstract: The Moon is not volcanically active at present, therefore, we rely on data from lunar samples, remote sensing, and numerical modeling to understand past lunar volcanism. The role of different volatile species in propelling lunar magma ascent and eruption remains unclear. We adapt a terrestrial magma ascent model for lunar magma ascent, considering different compositions of picritic magmas and various abundances of H2, H2O, and CO (measured and estimated) for these magmas. We also conduct a sensitivity analysis to investigate the relationship between selected input parameters (pre‐eruptive pressure, temperature, conduit radius, and volatile content) and given outputs (exit gas volume fraction, velocity, pressure, and mass eruption rate). We find that, for the model simulations containing H2O and CO, CO was more significant than H2O in driving lunar magma ascent, for the range of volatile contents considered here. For the simulations containing H2 and CO, H2 had a similar or slightly greater control than CO on magma ascent dynamics. Our results showed that initial H2 and CO content has a strong control on exit velocity and pressure, two factors that strongly influence the formation of an eruption plume, pyroclast ejection, and overall deposit morphology. Our results highlight the importance of (a) quantifying and determining the origin of CO, and (b) understanding the abundance of different H‐species present within the lunar mantle. Quantifying the role of volatiles in driving lunar volcanism provides an important link between the interior volatile content of the Moon and the formation of volcanic deposits on the lunar surface
Heterogeneous distribution of histone methylation in mature human sperm
Purpose
To analyze the presence of various histone modifications in ejaculated human spermatozoa
Methods
In this prospective study, seminal ejaculates from 39 normozoospermic individuals were evaluated for semen analysis and the presence of histone modifications in isolated nuclei.
Results
We observed heterogeneous presence of histone methylation in normal mature human sperm. We observed that 12 to 30 % of the nuclei of normal sperm contain a heterogeneous distribution of the marks H3K4Me1, H3K9Me2, H3K4Me3, H3K79Me2, and H3K36Me3. Moreover, the presence of these marks is higher in the poor motile fraction of the ejaculate, which is associated with poor morphology and functional quality. In contrast, we did not observe histone acetylation (H3K4Ac and H4K5Ac) in normal or abnormal mature human sperm
Conclusions
Defects in the process of spermatogenesis may alter the correct epigenetic programing in mature sperm. Further studies are required to evaluate the impact of these findings in human infertilityFil: la Spina, Florenza Antonella. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Romanato, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Brugo Olmedo, Santiago. Centro Médico Seremas; ArgentinaFil: de Vicentiis, Sabrina. Centro Médico Seremas; ArgentinaFil: Julianelli, Vanina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Rivera, Rocío M.. University Of Missouri; Estados UnidosFil: Buffone, Mariano Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentin
Degassing behavior of Mt. Etna volcano (Italy) during 2007-2008, inferred
Studies on volcanic degassing have recently shown the important role of volatile release from active volcanoes
in understanding magmatic processes prior to eruptions. Here we present and discuss the evolution of magmatic
degassing that preceded and accompanied the 2008 Mt. Etna eruption. We tracked the ascent of magma bodies
by high-temporal resolution measurements of SO2 emission rates and discrete sampling of SO2/HCl and SO2/HF
molar ratios in the crater plume, as well as by periodic measurement of soil CO2 emission rates. Our data suggest
that the first signs of upward migration of gas-rich magma before the 2008 eruption were observed in June 2007,
indicated by a strong increase in soil CO2 efflux followed by a slow declining trend in SO2 flux and halogens. This
degassing behavior preceded the mid-August 2007 summit activity culminated with the September 4th paroxysmal
event. Five months later, a new increase in both soil CO2 and SO2 emission rates occurred before the November
23rd paroxysm, to drop down in late December. In the following months, geochemical parameters showed high
variability, characterized by isolated sudden increases occurred in early December 2007 and late March 2008. In
early May soil CO2, SO2 emission rates and S/Cl molar ratio gradually increased. Crater degassing peaked on
May 13th marking the onset of the eruption. Eruptive activity was accompanied by a general steady-state of SO2
flux characterized by two main degassing cycles. These cycles preceded explosive activity at the eruptive vents,
indicating terminal new-arrival of deep gas-rich magma bodies in the shallow plumbing system of Mt Etna. Conversely,
halogens described a slight increasing trend till the end of 2008. These observations suggest an impulsive
syn-eruptive dynamics of magma transfer from depth to the surface. Differently from the SO2 emission rates, the
S/Cl ratio and the soil CO2 efflux values showed an increasing trend from mid-April to mid-July 2008, indicating
steady-increasing input of deeper, gas-rich magma. Since August, geochemical parameters decreased, suggesting
that new magma has not arrived from depth. According to our interpretation, both the CO2 efflux and the S/Cl ratio
increases observed in early November may indicate a new input of fresh magma form depth. Finally, the estimated
volume of degassing magma showed substantial equilibrium between degassed and erupted magma suggesting an
“eruptive” steady-state of the volcano
883 An anti-carcinoma monoclonal antibody (mAb) NEO-201 can also target human acute myeloid leukemia (AML) cell lines in vitro
BackgroundNEO-201 is an IgG1 mAb targeting variants of CEACAM5/6 and has demonstrated tumor sensitivity and specificity in epithelial cells. Functional analysis has revealed that NEO-201 can engage innate immune effector mechanisms including ADCC and CDC to directly kill tumor cells expressing its target. A recent Phase 1 clinical trial at the NCI has determined both safety and recommended Phase 2 dosing. We have also seen the expression of the NEO-201 target on hematologic cells, specifically Tregs and neutrophils. Due to epitope being expressed both on malignant epithelial cells as well as several hematologic cells, we designed this study to explore the reactivity of NEO-201 against hematological neoplastic cells in vitro.MethodsPhenotypic analysis was conducted by flow cytometry. Cell lines used were six AML (HL60, U937, MOLM13, AML2, IMS-M2 and OCL-AML3), two multiple myelomas (MM) (OPM2, MM1.S), two acute lymphoblastic leukemia (ALL) (SUP-B15, RPMI8402) and four mantle cell lymphoma (MCL) (Jeko-1, Z138, JVM2 and JVM13). Markers used for flow cytometry analysis were CD15, CD45, CD38, CD138, CD14, CD19 and NEO-201. Functional analysis was performed by evaluating the ability of NEO-201 to mediate ADCC activity against AML cell lines using human NK cells as effector cells.Results5 of 6 AML cell lines tested bind to NEO-201 and the% of positive cells were 47%, 99.5%,100%,100% and 97.8% for HL60, U937, MOLM13, AML3 and IMS-M2, respectively. The% of positive cells in the two MM cell line were 99% and 18% for OPM2 and MM1.S, respectively. NEO-201 binding was not detected in the two ALL and the four MCL cell lines tested. Functional analysis has demonstrated that NEO-201 can mediate ADCC activity against the AML cell line (HL60) tested.ConclusionsThis study demonstrates that NEO-201 mAb's target is expressed in most of the AML cell lines tested in vitro. In addition, we have shown it can mediate ADCC activity against HL60 cells (AML). Together, these findings provide a rationale for further investigation of the role of NEO-201 in AML as well as MM, further exploring patient PBMCs and bone marrow samples
Investigation about the presence of 20-hydroxyecdysone and flavonoids in several plant species and in a terrestrial isopod target species, Armadillo officinalis (Dumeril, 1816) (Crustacea, Isopoda, Oniscidea)
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