770 research outputs found
First Abundance Measurement of Organic Molecules in the Atmosphere of HH 212 Protostellar Disk
HH 212 is one of the well-studied protostellar systems, showing the first
vertically resolved disk with a warm atmosphere around the central protostar.
Here we report a detection of 9 organic molecules (including newly detected
ketene, formic acid, deuterated acetonitrile, methyl formate, and ethanol) in
the disk atmosphere, confirming that the disk atmosphere is, for HH 212, the
chemically rich component, identified before at a lower resolution as a
"hot-corino". More importantly, we report the first systematic survey and
abundance measurement of organic molecules in the disk atmosphere within
40 au of the central protostar. The relative abundances of these molecules are
similar to those in the hot corinos around other protostars and in Comet
Lovejoy. These molecules can be either (i) originally formed on icy grains and
then desorbed into gas phase or (ii) quickly formed in the gas phase using
simpler species ejected from the dust mantles. The abundances and spatial
distributions of the molecules provide strong constraints on models of their
formation and transport in star formation. These molecules are expected to form
even more complex organic molecules needed for life and deeper observations are
needed to find them.Comment: 12 pages, 4 figure
Strong enhancement of chlorophyll a concentration by a weak typhoon
Recent studies demonstrate that chlorophyll a (chl a) concentrations in the
surface ocean can be significantly enhanced due to typhoons. The present study
investigated chl a concentrations in the middle of the South China Sea (SCS)
from 1997-2007. Only the Category1 (minimal) Typhoon Hagibis (2007) had a
notable effect on the chl a concentrations. Typhoon Hagibis had a strong
upwelling potential due to its location near the equator, and the forcing time
of the typhoon (>82 h) was much longer than the geostrophic adjustment time
(~63 h). The higher upwelling velocity and the longer forcing time increased
the depth of the mixed-layer, which consequently induced a strong phytoplankton
bloom that accounted for about 30% of the total annual chl a concentration in
the middle of the SCS. The implication is that the forcing time of a typhoon
should be long enough to establish a strong upwelling and consequently for the
induction of significant upper ocean responses.Comment: Typhoon-Ocean Environment interaction
Comparison Between Single Loading–Unloading Indentation and Continuous Stiffness Indentation
Experiments are performed on fused silica, Si, and duplex stainless steel to examine whether the CSM (continuous stiffness indentation) method will provide approximately the “same” results of contact modulus and indentation hardness as those measured from the quasi-static single loading–unloading indentation. The experimental results show that the elastic modulus measured by the CSM method is compatible with that by the quasi-static loading–unloading method for hard materials, while there exists a percentage difference of ∼21.3% between the smallest value and the largest vale of the measured indentation hardnesses from the CSM method for fused silica and a percentage difference of ∼15.3% between the hardnesses measured by the CSM method and the single indentation for duplex stainless steel. The large percentage difference suggests that the indentation hardness measured by the CSM method may not be compatible with that measured by the quasi-static loading–unloading method for hard materials. The finite element results reveal the percentage difference between the indentation hardness at the wave peak and that at the wave valley for the CSM method increases with the increase of the ratio of elastic modulus to yield stress
Anthriscifolcine A, a C18-diterpenoid alkaloid
The title compound, C26H39NO7, which was isolated from Delphinium anthriscifolium var. majus, has a lycoctonine carbon skeleton containing four six-membered rings (A, B, D and E) and three five-membered rings (C, F and G). Rings A, B and E adopt chair conformation, while ring D adopts a boat conformation. Rings C and F adopt envelope conformations
Causal analysis between altered levels of interleukins and obstructive sleep apnea
BackgroundInflammation proteins including interleukins (ILs) have been reported to be related to obstructive sleep apnea (OSA). The aims of this study were to estimate the levels for several key interleukins in OSA and the causal effects between them.MethodWeighted mean difference (WMD) was used to compare the expression differences of interleukins between OSA and control, and the changed levels during OSA treatments in the meta-analysis section. A two-sample Mendelian randomization (MR) was used to estimate the causal directions and effect sizes between OSA risks and interleukins. The inverse-variance weighting (IVW) was used as the primary method followed by several other MR methods including MR Egger, Weighted median, and MR-Robust Adjusted Profile Score as sensitivity analysis.ResultsNine different interleukins—IL-1β, IL-2, IL-4, IL-6, IL-8, IL-12, IL-17, IL-18, and IL-23—were elevated in OSA compared with control to varying degrees, ranging from 0.82 to 100.14 pg/ml, and one interleukin, IL-10, was decreased by 0.77 pg/ml. Increased IL-1β, IL-6, and IL-8 rather than IL-10 can be reduced in OSA by effective treatments. Further, the MR analysis of the IVW method showed that there was no significant evidence to support the causal relationships between OSA and the nine interleukins—IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-17, and IL-18. Among them, the causal effect of OSA on IL-5 was almost significant [estimate: 0.267 (−0.030, 0.564), p = 0.078]. These results were consistent in the sensitivity analysis.ConclusionsAlthough IL-1β, IL-2, IL-4, IL-6, IL-8, IL-12, IL-17, IL-18, and IL-23 were increasing and IL-10 was reducing in OSA, no significant causal relationships were observed between them by MR analysis. Further research is needed to test the causality of OSA risk on elevated IL-5 level
Bis[1,3-bis(1-methyl-1H-benzimidazol-2-yl)-2-oxapropane]cadmium dipicrate acetonitrile sesquisolvate 0.25-hydrate
In the title compound, [Cd(C18H18N4O)2](C6H2N3O7)2·1.5CH3CN·0.25H2O, the CdII ion is coordinated by four N atoms and two O atoms from two tridentate 1,3-bis(1-methyl-1H-benzimidazol-2-yl)-2-oxopropane ligands in a distorted octahedral coordination environment. The lengths of the chemically equivalent Cd—O bonds [2.4850 (16) and 2.5488 (16)Å] are signiificantly different. One of the picrate anions is disordered over two sets of sites, with refined occupancies of 0.504 (15) and 0.496 (15). A 0.5-occupancy acetonitrile solvent molecule is disordered over two sites with equal occupancies. The H atoms of a 0.25-occupancy solvent water molecule were neither located nor included in the refinement
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