The H13CN/HC15N Abundance Ratio in Dense Cores: Possible Source‐to‐Source Variation of Isotope Abundances?

Using the Yebes 40 m and IRAM 30 m radiotelescopes, we detected two series of harmonically related lines in space that can be fitted to a symmetric rotor. The lines have been seen towards the cold dense cores TMC-1, L483, L1527, and L1544. High level of theory ab initio calculations indicate that the best possible candidate is the acetyl cation, CH3CO+, which is the most stable product resulting from the protonation of ketene. We have produced this species in the laboratory and observed its rotational transitions Ju = 10 up to Ju = 27. Hence, we report the discovery of CH3CO+ in space based on our observations, theoretical calculations, and laboratory experiments. The derived rotational and distortion constants allow us to predict the spectrum of CH3CO+ with high accuracy up to 500 GHz. We derive an abundance ratio N(H2CCO)/N(CH3CO+) ∼ 44. The high abundance of the protonated form of H2CCO is due to the high proton affinity of the neutral species. The other isomer, H2CCOH+, is found to be 178.9 kJ mol−1 above CH3CO+. The observed intensity ratio between the K = 0 and K = 1 lines, ∼2.2, strongly suggests that the A and E symmetry states have suffered interconversion processes due to collisions with H and/or H2, or during their formation through the reaction of H3+ with H2CCO.

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Ultrastructure of superficial neuromasts in the mottled sculpin, Cottus bairdi

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100156778 ◽

1989 ◽

Vol 47 ◽

pp. 958-959

Author(s):

W.R. Jones ◽

S. Coombs ◽

J. Janssen

Keyword(s):

Hair Cells ◽

Lateral Line System ◽

Electron Microscopic ◽

Line System ◽

Dense Cores ◽

Sensory Hair Cells ◽

Cytoplasmic Vesicles ◽

Cottus Bairdi ◽

Mottled Sculpin ◽

Upper Third

The lateral line system of the mottled sculpin, like that of most bony fish, has both canal (CNM) and superficial (SNM) sensory end organs, neuromasts, which are distributed on the head and trunk in discrete, readily identifiable groupings (Fig. 1). CNM and SNM differ grossly in location and in overall size and shape. The former are located in subdermal canals and are larger and asymmetric in shape, The latter are located directly on the surface of the skin and are much smaller and more symmetrical It has been suggested that the two may differ at a more fundamental level in such functionally related parameters as extent of myelination of innervating fibers and the absence of efferent innervation in SNM. The present study addresses the validity of these last two features as distinguishing criteria by examining the structure of those SNM populations indicated in Fig. 1 at both the light and electron microscopic levels.All of the populations of SNM examined conform in general to previously published descriptions, consisting of a neuroepithelium composed of sensory hair cells, support cells and mantle cells, Several significant differences from these accounts have, however, emerged. Firstly, the structural composition of the innervating fibers is heterogeneous with respect to the extent of myelination. All SNM groups, with the possible exception of the TRrs and CFLs, possess both myelinated and unmyelinated fibers within the neuroepithelium proper (Fig. 2), just as do CNM. The extent of myelina- tion is quite variable, with some fibers sheath terminating just before crossing the neuroepithelial basal lamina, some just after and a few retaining their myelination all the way to the base of the hair cells in the upper third of the neuroepithelium. Secondly, all SNMs possess fibers that may, on the basis of ultrastructural criteria, be identified as efferent. Such fibers contained numerous cytoplasmic vesicles, both clear and with dense cores. In regions where such fibers closely apposed hair cells, subsynaptic cisternae were observed in the hair cell (Fig. 3).

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Patterns in diversity and composition of the microbenthos of subarctic intertidal beaches with different morphodynamics

Marine Ecology Progress Series ◽

10.3354/meps13419 ◽

2020 ◽

Vol 648 ◽

pp. 19-38

Author(s):

AI Azovsky ◽

YA Mazei ◽

MA Saburova ◽

PV Sapozhnikov

Keyword(s):

Species Abundance ◽

Abundance Ratio ◽

Wave Action ◽

Coarse Grained ◽

Sediment Properties ◽

Β Diversity ◽

Α Diversity ◽

Wide Range ◽

Similar Mode ◽

Abundance And Diversity

Diversity and composition of benthic diatom algae and ciliates were studied at several beaches along the White and Barents seas: from highly exposed, reflective beaches with coarse-grained sands to sheltered, dissipative silty-sandy flats. For diatoms, the epipelic to epipsammic species abundance ratio was significantly correlated with the beach index and mean particle size, while neither α-diversity measures nor mean cell length were related to beach properties. In contrast, most of the characteristics of ciliate assemblages (diversity, total abundance and biomass, mean individual weight and percentage of karyorelictids) demonstrated a strong correlation to beach properties, remaining low at exposed beaches but increasing sharply in more sheltered conditions. β-diversity did not correlate with beach properties for either diatoms or ciliates. We suggest that wave action and sediment properties are the main drivers controlling the diversity and composition of the intertidal microbenthos. Diatoms and ciliates, however, demonstrated divergent response to these factors. Epipelic and epipsammic diatoms exhibited 2 different strategies to adapt to their environments and therefore were complementarily distributed along the environmental gradient and compensated for each other in diversity. Most ciliates demonstrated a similar mode of habitat selection but differed in their degree of tolerance. Euryporal (including mesoporal) species were relatively tolerant to wave action and therefore occurred under a wide range of beach conditions, though their abundance and diversity were highest in fine, relatively stable sediments on sheltered beaches, whereas the specific interstitial (i.e. genuine microporal) species were mostly restricted to only these habitats.

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Interaction between molecular outflows and dense gas in the cluster-forming region OMC-2/FIR4

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307002633 ◽

2006 ◽

Vol 2 (S237) ◽

pp. 475-475

Author(s):

Yoshito Shimajiri ◽

S. Takahashi ◽

S. Takakuwa ◽

M. Saito ◽

R. Kawabe

Keyword(s):

Cluster Formation ◽

Major Axis ◽

List Type ◽

Dense Gas ◽

Continuum Source ◽

Molecular Outflows ◽

Molecular Outflow ◽

Dense Cores ◽

Potential Source ◽

Molecular Lines

AbstractSince most stars are born as members of clusters (Lada & Lada 2003), it is important to clarified the detailed mechanism of cluster formation for comprehensive understanding of star formation. However, our current understanding of cluster formation is limited due to the followings; (a)Cluster forming regions are located at the far distance.(b)There are complex mixtures of outflows and dense gas in cluster forming regions. So, we focused on the Orion Molecular Cloud 2 region (OMC-2), a famous cluster-forming region (Lada & Lada 2003) and the most nearest GMC. We observed the FIR 4 region with the Nobeyama Millimeter Array(NMA), Atacama Submillimeter Telescope Experiment (ASTE). In this region, there are 3 protostars (FIR3, FIR4, FIR5) which were identified as 1.3 mm dust continuum sources (Chini et al. 1997) and driving sources of mixed outflows, and FIR 4 is the most strongest source of 1.3 mm dust continuum in OMC-2. Molecular lines we adopted are a high density (105cm−3) gas tracer of H13CO+ (J=1-0), a molecular outflow tracer of 12CO(J=1-0) and 12CO(J=3-2), and SiO(J=2-1 v=0) as a tracer of shocks associated with an interaction between outflows and dense gas.From results of the 12CO(J=1-0) outflow, H13CO+ dense gas, and the SiO shock, the outflow from FIR 3 interacts with dense gas in the FIR 4 region. Moreover the Position-Velocity diagram along the major axis of the 12CO(J=3-2) outflow shows that the 12CO(J=1-0) and SiO emission exhibits a L shape (the line widths increase in the interacting region in morphology). This is an evidence of interaction between the outflows and dense gas (Takakuwa et al. 2003). From result of the 3 mm dust continuum, the interacted region by the molecular outflow of FIR 3 is an assemble of seven dense cores. The mass of each core is 0.1-0.8 M. This clumpy structure is evident only at FIR 4 in the entire OMC-2/3 region. There are possible that two cores are in the proto-stellar phase, because 3 mm dust continuum source correspond to NIR source or 3.6 cm f-f jet source. From these results, cores in the FIR 4 region may be potential source of the next-generation stars. In the other words, there is a possibility that the molecular outflow ejected from FIR 3 is triggering the cluster formation in the FIR 4 region.

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Accretion and Outflow Activity in the Earliest Phases of Star-Formation: CO, Sub-mm Continuum, and Near-Infrared Observations

International Astronomical Union Colloquium ◽

10.1017/s0252921100043645 ◽

1997 ◽

Vol 163 ◽

pp. 725-726

Author(s):

K.-W. Hodapp ◽

E. F. Ladd

Keyword(s):

Near Infrared ◽

Spectral Energy Distribution ◽

Far Infrared ◽

Point Sources ◽

Spectral Energy ◽

Infrared Observations ◽

Circumstellar Material ◽

Dense Cores ◽

Wavelength Radiation ◽

Main Component

Stars in the earliest phases of their formation, i.e., those accreting the main component of their final mass, are deeply embedded within dense cores of dust and molecular material. Because of the high line-of-sight extinction and the large amount of circumstellar material, stellar emission is reprocessed by dust into long wavelength radiation, typically in the far-infrared and sub-millimeter bands. Consequently, the youngest sources are strong submillimeter continuum sources, and often undetectable as point sources in the near-infrared and optical. The most deeply embedded of these sources have been labelled “Class 0” sources by André, Ward-Thompson, & Barsony (1994), in an extension of the spectral energy distribution classification scheme first proposed by Adams, Lada, & Shu (1987).

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The interstellar medium in young supernova remnants: key to the production of cosmic X-rays and $\gamma $-rays

Astrophysics and Space Science ◽

10.1007/s10509-021-03960-4 ◽

2021 ◽

Vol 366 (6) ◽

Author(s):

Hidetoshi Sano ◽

Yasuo Fukui

Keyword(s):

Interstellar Medium ◽

Supernova Remnants ◽

Cosmic Ray ◽

High Energy ◽

X Rays ◽

Interstellar Gas ◽

High Energy Radiation ◽

Dense Cores ◽

The Relationship ◽

Turbulent Velocity Field

AbstractWe review recent progress in elucidating the relationship between high-energy radiation and the interstellar medium (ISM) in young supernova remnants (SNRs) with ages of ∼2000 yr, focusing in particular on RX J1713.7−3946 and RCW 86. Both SNRs emit strong nonthermal X-rays and TeV $\gamma $ γ -rays, and they contain clumpy distributions of interstellar gas that includes both atomic and molecular hydrogen. We find that shock–cloud interactions provide a viable explanation for the spatial correlation between the X-rays and ISM. In these interactions, the supernova shocks hit the typically pc-scale dense cores, generating a highly turbulent velocity field that amplifies the magnetic field up to 0.1–1 mG. This amplification leads to enhanced nonthermal synchrotron emission around the clumps, whereas the cosmic-ray electrons do not penetrate the clumps. Accordingly, the nonthermal X-rays exhibit a spatial distribution similar to that of the ISM on the pc scale, while they are anticorrelated at sub-pc scales. These results predict that hadronic $\gamma $ γ -rays can be emitted from the dense cores, resulting in a spatial correspondence between the $\gamma $ γ -rays and the ISM. The current pc-scale resolution of $\gamma $ γ -ray observations is too low to resolve this correspondence. Future $\gamma $ γ -ray observations with the Cherenkov Telescope Array will be able to resolve the sub-pc-scale $\gamma $ γ -ray distribution and provide clues to the origin of these cosmic $\gamma $ γ -rays.

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Neutrophil Extracellular Trap Formation Correlates with Favorable Overall Survival in High Grade Ovarian Cancer

Cancers ◽

10.3390/cancers12020505 ◽

2020 ◽

Vol 12 (2) ◽

pp. 505 ◽

Cited By ~ 3

Author(s):

Besnik Muqaku ◽

Dietmar Pils ◽

Johanna C. Mader ◽

Stefanie Aust ◽

Andreas Mangold ◽

...

Keyword(s):

Patient Outcome ◽

Ovarian Cancer ◽

Abundance Ratio ◽

Neutrophil Extracellular Trap ◽

High Grade ◽

Serous Ovarian Cancer ◽

Association Network ◽

Tumor Spread ◽

Peritoneal Tumor ◽

Extracellular Trap

It is still a question of debate whether neutrophils, often found in the tumor microenvironment, mediate tumor-promoting or rather tumor-inhibiting activities. The present study focuses on the involvement of neutrophils in high grade serous ovarian cancer (HGSOC). Macroscopic features classify two types of peritoneal tumor spread in HGSOC. Widespread and millet sized lesions characterize the miliary type, while non-miliary metastases are larger and associated with better prognosis. Multi-omics and FACS data were generated from ascites samples. Integrated data analysis demonstrates a significant increase of neutrophil extracellular trap (NET)-associated molecules in non-miliary ascites samples. A co-association network analysis performed with the ascites data further revealed a striking correlation between NETosis-associated metabolites and several eicosanoids. The congruence of data generated from primary neutrophils with ascites analyses indicates the predominance of NADPH oxidase 2 (NOX)-independent NETosis. NETosis is associated with protein S100A8/A9 release. An increase of the S100A8/CRP abundance ratio was found to correlate with favorable survival of HGSOC patients. The analysis of additional five independent proteome studies with regard to S100A8/CRP ratios confirmed this observation. In conclusion, NET formation seems to relate with better cancer patient outcome.

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The accumulation of noradrenaline in constricted sympathetic nerves as studied by fluorescence and electron microscopy

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1967.0027 ◽

1967 ◽

Vol 167 (1008) ◽

pp. 282-292 ◽

Cited By ~ 68

Keyword(s):

Sympathetic Nerves ◽

Close Correlation ◽

Electron Microscopic ◽

Hypogastric Nerve ◽

Fluorescent Material ◽

Dense Cores ◽

Fluorescence And Electron Microscopy ◽

Granular Vesicles ◽

Electron Dense Core ◽

Microscopic Findings

The effects of constricting post-ganglionic sympathetic nerves have been studied in the cat splenic nerve and guinea-pig hypogastric nerve. The results obtained using a fluorescence method for the histochemical localization of noradrenaline have been compared with electron microscopic findings. A close correlation was found between the accumulation of fluorescent material, attributable to noradrenaline, and of vesicles with an electron dense core (granular vesicles) believed to contain noradrenaline, proximal to the constriction in these nerves. This accumulation of noradrenaline was visible by 1 h after operation and increased rapidly in amount during the succeeding hours. It apparently reached a maximum after approximately 2 days and was found in what appeared to be newly formed axons 3 to 4 days after operation. Reserpine reduces the fluorescence and the number of vesicles with electron dense cores which accumulate proximal to the constriction. It is suggested, (1) that the fluorescent material is due, at least in part, to the presence of the granular vesicles, and (2) that the constriction has blocked the normal proximo-distal movement of noradrenaline which is believed to occur in post-ganglionic sympathetic axons.

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