Using energy-dispersive x-ray diffraction techniques together with the theory describing lattice strains under nonhydrostatic compression, the behavior of a layered sample of gold and rhenium has ...been studied at pressures of 14-37 GPa. For gold, the uniaxial stress component t is consistent with earlier studies and can be described by t=0.06+0.015P where P is the pressure in GPa. The estimated single-crystal elastic moduli are in reasonable agreement with trends based on extrapolated low-pressure data. The degree of elastic anisotropy increases as {alpha}, the parameter which characterizes stress-strain continuity across grain boundaries, is reduced from 1.0 to 0.5. For rhenium, the apparent equation of state has been shown to be strongly influenced by nonhydrostatic compression, as evidenced by its dependence on the angle {psi} between the diffracting plane normal and the stress axis. The bulk modulus obtained by inversion of nonhydrostatic compression data can differ by nearly a factor of 2 at angles of 0 degree sign and 90 degree sign . On the other hand, by a proper choice of {psi}, d spacings corresponding to quasihydrostatic compression can be obtained from data obtained under highly nonhydrostatic conditions. The uniaxial stress in rhenium over the pressure range from 14-37 GPa can be described by t=2.5+0.09P. The large discrepancy between x-ray elastic moduli and ultrasonic data and theoretical calculations indicates that additional factors such as texturing or orientation dependence of t need to be incorporated to more fully describe the strain distribution in hexagonal-close-packed metals. (c) 1999 The American Physical Society.
Previous analysis of potato spindle tuber viroid (PSTVd) RNA-infected tobacco plants has suggested that an RNA-DNA interaction could trigger de novo methylation of PSTVd transgene sequences. Using ...the genomic sequencing technique, the methylation pattern associated with the RNA-directed DNA methylation process has been characterized. Three different PSTVd transgene constructs all showed a similar pattern of methylation. Most of the cytosines at symmetrical as well as non-symmetrical positions appeared to be methylated in both DNA strands of the viroid sequences. Heavy methylation was mostly restricted to the viroid cDNA sequences. Flanking DNA regions immediately adjacent to the viroid cDNA displayed a lower but significant level of cytosine methylation. The observation that the heavy methylation was essentially co-extensive with the length of the PSTVd cDNA sequences provided evidence that a direct RNA-DNA interaction can act as a strong and highly specific signal for de novo DNA methylation. These data also confirmed that de novo methylation was not limited to canonical CpG and CpNpG sites, but can also involve all the cytosine residues located in the genomic region where the RNA-DNA interaction takes place.
Magnesiowüstite (Mg,Fe)O is the second most abundant mineral of Earth's lower mantle. Understanding its stability under lower mantle conditions is crucial for interpreting the physical and chemical ...properties of the whole Earth. Previous studies in an externally heated diamond anvil cell suggested that magnesiowüstites decompose into two components, Fe-rich and Mg-rich magnesiowüstites at 86 GPa and 1,000 K. Here we report an in situ study of two magnesiowüstites (Mg-0.39,Fe0.61)O and (Mg0.25, Fe0.75)O at pressures and temperatures that overlap with mantle conditions, using a laser-heated diamond anvil cell combined with synchrotron x-ray diffraction. Our results show that addition of Mg in wüstite (FeO) can stabilize the rock-salt structure to much higher pressures and temperatures. In contrast to the previous studies, our results indicate that Mg-rich magnesiowüstite is stable in the rock-salt structure in the lower mantle. The physical and chemical properties of magnesiowüstite should change gradually and continuously in the lower mantle, suggesting that it does not make a significant contribution to seismic-wave heterogeneity of the lower mantle. Stable Mg-rich magnesiowüstite in lowermost mantle can destabilize FeO in the core-mantle boundary region and remove FeO from the outer core.
Abstract
Research can be more transparent and collaborative by using Findable, Accessible, Interoperable, and Reusable (FAIR) principles to publish Earth and environmental science data. Reporting ...formats—instructions, templates, and tools for consistently formatting data within a discipline—can help make data more accessible and reusable. However, the immense diversity of data types across Earth science disciplines makes development and adoption challenging. Here, we describe 11 community reporting formats for a diverse set of Earth science (meta)data including cross-domain metadata (dataset metadata, location metadata, sample metadata), file-formatting guidelines (file-level metadata, CSV files, terrestrial model data archiving), and domain-specific reporting formats for some biological, geochemical, and hydrological data (amplicon abundance tables, leaf-level gas exchange, soil respiration, water and sediment chemistry, sensor-based hydrologic measurements). More broadly, we provide guidelines that communities can use to create new (meta)data formats that integrate with their scientific workflows. Such reporting formats have the potential to accelerate scientific discovery and predictions by making it easier for data contributors to provide (meta)data that are more interoperable and reusable.
Through their capacity to sense danger signals and to generate active interleukin-1β (IL-1β), inflammasomes occupy a central role in the inflammatory response. In contrast to IL-1β, little is known ...about how IL-1α is regulated. We found that all inflammasome activators also induced the secretion of IL-1α, leading to the cosecretion of both IL-1 cytokines. Depending on the type of inflammasome activator, release of IL-1α was inflammasome dependent or independent. Calcium influx induced by the opening of cation channels was sufficient for the inflammasome-independent IL-1α secretion. In both cases, IL-1α was released primarily in a processed form, resulting from intracellular cleavage by calpain-like proteases. Inflammasome-caspase-1-dependent release of IL-1α and IL-1β was independent of caspase-1 catalytic activity, defining a mode of action for caspase-1. Because inflammasomes contribute to the pathology of numerous chronic inflammatory diseases such as gout and diabetes, IL-1α antagonists may be beneficial in the treatment of these disorders.
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► IL-1α is cosecreted with IL-1β upon inflammasome activation ► IL-1α secretion can be inflammasome dependent or independent ► Caspase-1 has a protease activity-independent function that controls IL-1 secretion ► Osmotic stress and TRP channel-activity induce inflammasome activation
Autophagy is a degradational pathway with pivotal roles in cellular homeostasis and survival, including protection of neurons in the central nervous system (CNS). The significance of autophagy as ...antiviral defense mechanism is recognized and some viruses hijack and modulate this process to their advantage in certain cell types. Here, we present data demonstrating that the human neurotropic herpesvirus varicella zoster virus (VZV) induces autophagy in human SH‐SY5Y neuronal cells, in which the pathway exerts antiviral activity. Productively VZV‐infected SH‐SY5Y cells showed increased LC3‐I‐LC3‐II conversion as well as co‐localization of the viral glycoprotein E and the autophagy receptor p62. The activation of autophagy was dependent on a functional viral genome. Interestingly, inducers of autophagy reduced viral transcription, whereas inhibition of autophagy increased viral transcript expression. Finally, the genotype of patients with severe ocular and brain VZV infection were analyzed to identify potential autophagy‐associated inborn errors of immunity. Two patients expressing genetic variants in the autophagy genes ULK1 and MAP1LC3B2, respectively, were identified. Notably, cells of both patients showed reduced autophagy, alongside enhanced viral replication and death of VZV‐infected cells. In conclusion, these results demonstrate a neuro‐protective role for autophagy in the context of VZV infection and suggest that failure to mount an autophagy response is a potential predisposing factor for development of severe VZV disease.
OBJECTIVES:Noninvasive imaging is increasingly accepted for the evaluation of atherosclerotic disease of the carotid arteries. We sought to evaluate the feasibility of a low-contrast media volume ...protocol for carotid computed tomography angiography (CTA) using a 128-slice-spiral-computed tomography scanner with a gantry rotation time of 300 milliseconds.
METHODS AND MATERIALS:Thirty consecutive patients underwent CTA for the evaluation of the carotid vessels, with a 128-section scanner. Fifteen patients were examined with a standard volume contrast injection protocol (group A)80 mL of contrast material (CM) were injected at 5 mL/s using the test bolus method to assess individual transit time. Another 15 patients were examined with a low-volume contrast media protocol (group B)30 mL CM were injected at 4 mL/s using bolus tracking to trigger the CTA acquisition. In both groups, contrast administration was followed by a saline flush. Image quality and segmental vascular enhancement as well as the presence and degree of arterial stenosis were independently evaluated by 2 radiologists. Venous enhancement and streak artifacts at the thoracic inlet because of highly concentrated CM in the subclavian veins were evaluated in both groups. Kappa statistic and Pearson correlation coefficient were used to quantify interobserver variability. Qualitative data were compared using the Wilcoxon signed rank test and student t test was used to investigate differences in segmental vessel attenuation.
RESULTS:All studies were of diagnostic quality in both groups. Interobserver agreement was high (κ = 0.82, group A; κ = 0.78, group B). Attenuation measurement showed excellent interobserver correlation in both groups (r > 0.9). Mean enhancement values were slightly higher in group A, but without statistical significance when averaged for all segments (P = 0.06). Streak artifacts impaired evaluation of 13 adjacent arterial segments in 8 patients at the level of the thoracic inlet in group A. In group B, only 1 segment was rated insufficient by both radiologists. Venous enhancement was significantly lower in group B (P = 0.04). The low-contrast protocol proved to be the more robust method with constant high arterial enhancement, less streak artifacts at the thoracic inlet, and less venous overlay.
CONCLUSION:Using the latest CT technology, optimal depiction of the craniocervical arteries can be archived with a low-volume (30 mL) CM protocol.
This article will give an overview of recent research into forms of address in Russian, with an emphasis on the choice between mbl (ty) and Bbl (vy), also taking into account the other members of the ...Slavonic languages as and when appropriate. The Slavonic languages, including, of course, Russian, share with the languages of Europe a well established system of informal and formal address in both pronouns and titles. With regard to second-person ('you') pronouns, Russian uses the singular pronoun mbl (French tu) for singular, familiar address, while the plural pronoun Bbl (French vous) is used obligatorily for addressing more than one person as 'you', but also for formal address to one person.' Taking as its point of departure Stone's article (Stone 1977) which gave an overview of the entire area of address in the Slavonic languages, we shall attempt to put into context the key research done on Russian during this approximately forty-year period in those areas identified by Stone as needing more work, as well as highlighting possible future avenues of inquiry into an area rich in linguistic and pragmatic complexity. Areas of interest discussed by Stone will be traced forward through subsequent research and include the following: (a) the treatment of address forms in descriptive grammars (2.1), (b) semantic agreement (2.2), (c) the social functions of address forms and the decline of non-reciprocal usage in Russian (2.3), (d) the use of mbl and Bbl in conjunction with the use of first name and patronymic (2.4), and, (e) switching between mbl and Bbl (2.5). Adapted from the source document
Iron-Nickel alloy in the Earth's core Lin, Jung-Fu; Heinz, Dion L.; Campbell, Andrew J. ...
Geophysical research letters,
15 May 2002, Letnik:
29, Številka:
10
Journal Article
Recenzirano
Odprti dostop
The phase relations of an Fe10wt%Ni alloy were investigated in a diamond anvil cell up to 86 GPa and 2382 K. Adding nickel into iron stabilizes the fcc phase to higher pressures and lower ...temperatures compared to pure iron, and a region of two‐phase coexistence between fcc and hcp phases is observed. Iron with up to 10 wt% nickel is likely to be in the hcp structure under inner core conditions. The axial ratio (c/a) of hcp‐Fe10wt%Ni has a weak pressure dependence, but it increases substantially with increasing temperature. The extrapolated c/a ratio at ∼5700 K and ∼86 GPa is approximately 1.64, lower than a theoretically predicted value of nearly 1.7 for hcp‐Fe at 5700 K and inner‐core pressure. A lower c/a ratio should have an effect on the longitudinal anisotropy of the hcp phase, and hence, may influence the interpretation of the seismic wave anisotropy of the inner core.
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