1,169 research outputs found

    HII region G46.5-0.2: the interplay between ionizing radiation, molecular gas and star formation

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    HII regions are particularly interesting because they can generate dense layers of gas and dust, elongated columns or pillars of gas pointing towards the ionizing sources, and cometary globules of dense gas, where triggered star formation can occur. Understanding the interplay between the ionizing radiation and the dense surrounding gas is very important to explain the origin of these peculiar structures, and hence to characterize triggered star formation. G46.5-0.2 (G46), a poorly studied galactic HII region located at about 4 kpc, is an excellent target to perform this kind of studies. Using public molecular data extracted from the Galactic Ring Survey (13CO J=1-0) and from the James Clerk Maxwell Telescope data archive (12CO, 13CO, C18O J=3-2, HCO+ and HCN J=4-3), and infrared data from the GLIMPSE and MIPSGAL surveys, we perform a complete study of G46, its molecular environment and the young stellar objects placed around it. We found that G46, probably excited by an O7V star, is located close to the edge of the GRSMC G046.34-00.21 molecular cloud. It presents a horse-shoe morphology opening in direction of the cloud. We observed a filamentary structure in the molecular gas likely related to G46 and not considerable molecular emission towards its open border. We found that about 10' towards the southwest of G46 there are some pillar-like features, shining at 8 um and pointing towards the HII region open border. We propose that the pillar-like features were carved and sculpted by the ionizing flux from G46. We found several young stellar objects likely embedded in the molecular cloud grouped in two main concentrations: one, closer to the G46 open border consisting of Class II type sources, and other one mostly composed by Class I type YSOs located just ahead the pillars-like features, strongly suggesting an age gradient in the YSOs distribution.Comment: Accepted for publication in The Astronomical Journal (April 14, 2015). Some figures were degraded to reduce file siz

    Factors affecting meibomian gland area loss in symptomatic adults

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    AIM: To characterize the distribution of meibomian gland (MG) area loss (MGL) and its relationship with demographic characteristics, mites, and symptoms. METHODS: This retrospective observational study included patients who visited the Dry Eye Clinic of Shenzhen Eye Hospital between June 2020 and August 2021. General patient characteristics, ocular symptoms, Demodex test results of the eyelid edges, and the results of a comprehensive ocular surface analysis were collected. MGL was analyzed using Image J software. RESULTS: This study enrolled 1204 outpatients aged 20-80 (40.70±13.44)y, including 357 males (29.65%) and 847 females (70.35%). The patients were classified into mild (n=155; 12.87%), moderate (n=795; 66.03%), severe (n=206; 17.11%), and extremely severe (n=48; 3.99%) MGL groups. MGL was significantly larger in female than in male (P=0.006). The degree of MGL also significantly differed in age (P<0.001) and the more numbers of mites with severity (P<0.001). Multivariate disordered multinomial logistic regression analysis identified that female sex, older age, secretory symptoms, and a large number of mites were risk factors for MGL (P<0.05). CONCLUSION: Patients with MGL are more likely to be older, female, more numbers of mites, and increased secretion

    Interactions of the Infrared bubble N4 with the surroundings

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    The physical mechanisms that induce the transformation of a certain mass of gas in new stars are far from being well understood. Infrared bubbles associated with HII regions have been considered to be good samples of investigating triggered star formation. In this paper we report on the investigation of the dust properties of the infrared bubble N4 around the HII region G11.898+0.747, analyzing its interaction with its surroundings and star formation histories therein, with the aim of determining the possibility of star formation triggered by the expansion of the bubble. Using Herschel PACS and SPIRE images with a wide wavelength coverage, we reveal the dust properties over the entire bubble. Meanwhile, we are able to identify six dust clumps surrounding the bubble, with a mean size of 0.50 pc, temperature of about 22 K, mean column density of 1.7 ×1022\times10^{22} cm−2^{-2}, mean volume density of about 4.4 ×104\times10^{4} cm−3^{-3}, and a mean mass of 320 M⊙M_{\odot}. In addition, from PAH emission seen at 8 ÎŒ\mum, free-free emission detected at 20 cm and a probability density function in special regions, we could identify clear signatures of the influence of the HII region on the surroundings. There are hints of star formation, though further investigation is required to demonstrate that N4 is the triggering source.Comment: Accepted by ApJ (16 pages, 11 figures, 9 tables

    The role of 245 phase in alkaline iron selenide superconductors revealed by high pressure studies

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    Here we show that a pressure of about 8 GPa suppresses both the vacancy order and the insulating phase, and a further increase of the pressure to about 18 GPa induces a second transition or crossover. No superconductivity has been found in compressed insulating 245 phase. The metallic phase in the intermediate pressure range has a distinct behavior in the transport property, which is also observed in the superconducting sample. We interpret this intermediate metal as an orbital selective Mott phase (OSMP). Our results suggest that the OSMP provides the physical pathway connecting the insulating and superconducting phases of these iron selenide materials.Comment: 32 pages, 4 figure

    Diverse and strain-specific metabolites patterns induced by fungal endophytes in grape cells of different varieties

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    The potential for endophytes to initiate changes in host secondary metabolism has been well documented. However, the mechanisms underlying endophyte-plant metabolic interactions are still poorly understood. Here, we analysed the effects of fungal endophytes on the metabolite profiles of grape cells from two cultivars: 'Cabernet Sauvignon' (CS) and 'Rose honey' (RH). Our results clearly showed that co-culture with endophytic fungi greatly modified the metabolic profiles in grape cells of both varieties. Treatments with endophytic fungal strains caused the numbers of detected metabolites to vary from 10 to 19 in CS cells and from 8 to 14 in RH cells. In addition, 5 metabolites were detected in all CS cell samples, while 4 metabolites were detected in all RH cell samples. Some endophytic fungal strains could even introduce novel metabolites into the co-cultured grape cells. The metabolic profiles of grape leaves shaped by endophytic fungi exhibited host selectivity and fungal strain specificity. In this assay, the fungal strains RH32 (Alternaria sp.) and MDR36 (Colletotrichum sp.) triggered an increased response of the detected metabolites, including the greatest increase in the metabolite contents in grape cells of both cultivars. No obvious effects in terms of metabolite numbers and contents in grape cells when co-cultured with fungal strains RH7 (Epicoccum sp.) and RH48 (Colletotrichum sp.) were observed. The results of this experiment suggest that endophytic fungi could be used to control the metabolic profiles of grapes and thus increase grape quality

    Anxiolytic effect of GABAergic neurons in the anterior cingulate cortex in a rat model of chronic inflammatory pain

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    Chronic pain easily leads to concomitant mood disorders, and the excitability of anterior cingulate cortex (ACC) pyramidal neurons (PNs) is involved in chronic pain-related anxiety. However, the mechanism by which PNs regulate pain-related anxiety is still unknown. The GABAergic system plays an important role in modulating neuronal activity. In this paper, we aimed to study how the GABAergic system participates in regulating the excitability of ACC PNs, consequently affecting chronic inflammatory pain-related anxiety. A rat model of CFA-induced chronic inflammatory pain displayed anxiety-like behaviors, increased the excitability of ACC PNs, and reduced inhibitory presynaptic transmission; however, the number of GAD65/67 was not altered. Interestingly, intra-ACC injection of the GABAAR agonist muscimol relieved anxiety-like behaviors but had no effect on chronic inflammatory pain. Intra-ACC injection of the GABAAR antagonist picrotoxin induced anxiety-like behaviors but had no effect on pain in normal rats. Notably, chemogenetic activation of GABAergic neurons in the ACC alleviated chronic inflammatory pain and pain-induced anxiety-like behaviors, enhanced inhibitory presynaptic transmission, and reduced the excitability of ACC PNs. Chemogenetic inhibition of GABAergic neurons in the ACC led to pain-induced anxiety-like behaviors, reduced inhibitory presynaptic transmission, and enhanced the excitability of ACC PNs but had no effect on pain in normal rats. We demonstrate that the GABAergic system mediates a reduction in inhibitory presynaptic transmission in the ACC, which leads to enhanced excitability of pyramidal neurons in the ACC and is associated with chronic inflammatory pain-related anxiety

    Anaplasma, Bartonella, and Rickettsia infections in Daurian ground squirrels (Spermophilus dauricus), Hebei, China

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    Rodents have been confirmed as hosts of various vector-borne zoonotic pathogens and are important for the maintenance of these microbes in nature. However, surveillance for zoonotic pathogens is limited for many wild rodent species in China, so our knowledge of pathogen ecology, genetic diversity, and the risk of cross-species transmission to humans is limited. In this study, 165 spleen samples of Daurian ground squirrels (Spermophilus dauricus) were collected from Weichang Manchu and the Mongolian Autonomous County of Hebei Province, China, and Rickettsia, Bartonella, and Anaplasma were identified by DNA detection using polymerase chain reaction (PCR). Sequence analysis identified eight bacterial pathogens: R. raoultii, R. sibirica, Candidatus R. longicornii, B. washoensis, B. grahamii, B. jaculi, A. capra, and Candidatus Anaplasma cinensis. Co-infection of B. grahamii and R. raoultii in one sample was observed. Our results demonstrated the genetic diversity of bacteria in Daurian ground squirrels and contributed to the distribution of these pathogens. Six species, A. capra, R. raoultii, R. sibirica, Candidatus R. longicornii, B. washoensis, and B. grahamii, are known to be pathogenic to humans, indicating a potential public health risk to the local human population, especially to herders who frequently have close contact with Daurian ground squirrels and are thus exposed to their ectoparasites

    The Relationship Between Autophagy and Brain Plasticity in Neurological Diseases

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    Autophagy, a catabolic degradation system, is utilized for destroying and recycling the damaged or unnecessary cellular components. Brain plasticity refers to the remarkable characteristics of brain neurons that change their structure and function according to previous experience. This review was performed by searching the relevant articles in databases of SCIENCEDIRECT, PUBMED, and Web of Science, from respective inception to January 2019. Here, we review the neuroprotective effect of autophagy in neurological diseases and the mechanism of autophagy in brain plasticity. Moreover, the mechanism of autophagy in the process of brain plasticity can provide the possibility for the development of new treatment methods in the future, thus benefiting patients with neurological diseases. In summary, autophagy and brain plasticity play important roles in neurological diseases
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