109 research outputs found

    A Gaia view on the star formation in the Monoceros OB1 and R1 associations

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    Stellar kinematics provides the key to understanding star formation process. In this respect, we present a kinematic study of the Monoceros OB1 (Mon OB1) and R1 (Mon R1) associations using the recent Gaia data and radial velocities of stars derived from high-resolution spectroscopy and the literature. A total of 728 members are selected using the criteria based on the intrinsic properties of young stars, parallaxes, and proper motions. The spatial distribution and kinematic properties of members show that these associations have distinct substructures. In Mon OB1, we find one northern group and two southern groups. Mon R1 is composed of three small stellar groups that are spatially and kinematically distinct. Some stars are found in a halo around these two associations. We detect patterns of expansion for most stellar groups in the associations. In addition, two stellar groups in Mon OB1 show the signature of rotation, which provides an important constraint on cluster formation. The star formation history of Mon OB1 is slightly revised. Star formation first occurred in the southern region and subsequently in the northern region. Recent star-forming events ignited deeper into the southern region, while some stars are escaping from Mon OB1, forming a halo. Mon R1 might have formed at the same epoch as the formation of the northern group in Mon OB1. Given that star formation is taking place on different scales along a large arc-like structure, Mon OB1 and Mon R1 may be the results of hierarchical star formation.Comment: 18 pages, 16 figures, accepted for publication in A

    Monotherapy versus combination therapy of statin and renin–angiotensin system inhibitor in ST-segment elevation myocardial infarction

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    Background: The beneficial effects of statin and renin–angiotensin system inhibitor (RASI) are well-known. In this retrospective cohort study,  2-year clinical outcomes were compared between monotherapy and combination therapy with statin and RASI in ST-segment elevation myocardial infarction (STEMI) patients after stent implantation. Methods: A total of 17,414 STEMI patients were enrolled and divided into the three groups (group A: 2448 patients, statin alone; group B: 2431 patients, RASI alone; and group C: 12,535 patients, both statin and RASI). The principal clinical endpoint was the occurrence of major adverse cardiac events (MACEs) defined as all-cause death, recurrent myocardial infarction, and any repeat revascularization. Results: After adjustment, the cumulative incidences of MACEs in group A (adjusted hazard ratio [aHR] 1.337; 95% confidence interval [CI] 1.064–1.679; p = 0.013) and in group B (aHR 1.375; 95% CI 1.149–1.646; p = 0.001) were significantly higher than in group C. The cumulative incidence of all-cause death in group A was significantly higher than that in group C (aHR 1.539; 95% CI 1.014–2.336; p = 0.043). The cumulative incidences of any repeat revascularization (aHR 1.317; 95% CI 1.031–1.681; p = 0.028), target lesion vascularization, and target vessel vascularization in group B were significantly higher than in group C. Conclusions: A Statin and RASI combination therapy significantly reduced the cumulative incidence of MACEs compared with a monotherapy of these drugs. Moreover, the combination therapy showed a reduced all-cause death rate compared with statin monotherapy, and a decreased repeat revascularization rate compared with RASI monotherapy

    Collagen Immobilization on Ultra-thin Nanofiber Membrane to Promote In Vitro Endothelial Monolayer Formation

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    The endothelialization on the poly (epsilon-caprolactone) nanofiber has been limited due to its low hydrophilicity. The aim of this study was to immobilize collagen on an ultra-thin poly (epsilon-caprolactone) nanofiber membrane without altering the nanofiber structure and maintaining the endothelial cell homeostasis on it. We immobilized collagen on the poly (epsilon-caprolactone) nanofiber using hydrolysis by NaOH treatment and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/sulfo-N-hydroxysulfosuccinimide reaction as a cost-effective and stable approach. NaOH was first applied to render the poly (epsilon-caprolactone) nanofiber hydrophilic. Subsequently, collagen was immobilized on the surface of the poly (epsilon-caprolactone) nanofibers using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/sulfo-N-hydroxysulfosuccinimide. Scanning electron microscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and fluorescence microscopy were used to verify stable collagen immobilization on the surface of the poly (epsilon-caprolactone) nanofibers and the maintenance of the original structure of poly (epsilon-caprolactone) nanofibers. Furthermore, human endothelial cells were cultured on the collagen-immobilized poly (epsilon-caprolactone) nanofiber membrane and expressed tight junction proteins with the increase in transendothelial electrical resistance, which demonstrated the maintenance of the endothelial cell homeostasis on the collagen-immobilized-poly (epsilon-caprolactone) nanofiber membrane. Thus, we expected that this process would be promising for maintaining cell homeostasis on the ultra-thin poly (epsilon-caprolactone) nanofiber scaffolds.11Ysciescopu

    A Gaia View on the Star Formation in the Monoceros OB1 and R1 Associations

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    Abstract Stellar kinematics provides the key to understanding the star formation process. In this respect, we present a kinematic study of the Monoceros OB1 (Mon OB1) and R1 (Mon R1) associations using the recent Gaia data and radial velocities of stars derived from high-resolution spectroscopy and the literature. A total of 728 members are selected using the criteria based on the intrinsic properties of young stars, parallaxes, and proper motions. The spatial distribution and kinematic properties of members show that these associations have distinct substructures. In Mon OB1, we find one northern group and two southern groups. Mon R1 is composed of three small stellar groups that are spatially and kinematically distinct. Some stars are found in a halo around these two associations. We detect patterns of expansion for most stellar groups in the associations. In addition, two stellar groups in Mon OB1 show the signature of rotation, which provides an important constraint on cluster formation. The star formation history of Mon OB1 is slightly revised. Star formation first occurred in the southern region and subsequently in the northern region. Recent star-forming events ignited deeper into the southern region, while some stars are escaping from Mon OB1, forming a halo. Mon R1 might have formed at the same epoch as the formation of the northern group in Mon OB1. Given that star formation is taking place on different scales along a large arc-like structure, Mon OB1 and Mon R1 may be the results of hierarchical star formation

    A Kinematic Perspective on the Formation Process of the Stellar Groups in the Rosette Nebula

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    peer reviewedStellar kinematics is a powerful tool for understanding the formation process of stellar associations. Here, we present a kinematic study of the young stellar population in the Rosette nebula using recent Gaia data and high-resolution spectra. We first isolate member candidates using the published mid-infrared photometric data and the list of X-ray sources. A total of 403 stars with similar parallaxes and proper motions are finally selected as members. The spatial distribution of the members shows that this star-forming region is highly substructured. The young open cluster NGC 2244 in the center of the nebula has a pattern of radial expansion and rotation. We discuss its implication on the cluster formation, e.g., monolithic cold collapse or hierarchical assembly. On the other hand, we also investigate three groups located around the border of the H II bubble. The western group seems to be spatially correlated with the adjacent gas structure, but their kinematics is not associated with that of the gas. The southern group does not show any systematic motion relative to NGC 2244. These two groups might be spontaneously formed in filaments of a turbulent cloud. The eastern group is spatially and kinematically associated with the gas pillar receding away from NGC 2244. This group might be formed by feedback from massive stars in NGC 2244. Our results suggest that the stellar population in the Rosette Nebula may form through three different processes: the expansion of stellar clusters, hierarchical star formation in turbulent clouds, and feedback-driven star formation

    Sex difference after acute myocardial infarction patients with a history of current smoking and long-term clinical outcomes: Results of KAMIR Registry

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    Background: The contribution of sex as an independent risk factor for cardiovascular disease still remains controversial. The present study investigated the impact of sex on long-term clinical outcomes in Korean acute myocardial infarction (AMI) patients with a history of current smoking on admission after drug-eluting stents (DESs). Methods: A total of 12,565 AMI patients (male: n = 11767 vs. female: n = 798) were enrolled. Major adverse cardiac events (MACEs) comprising all-cause death, recurrent myocardial infarction (Re-MI), and any repeat revascularization were the primary outcomes that were compared between the two groups. Probable or definite stent thrombosis (ST) was the secondary outcome. Results: After adjustment, the early (30 days) cumulative incidences of MACEs (adjusted hazard ratio [aHR]: 1.457; 95% confidence interval [CI]: 1.021–2.216; p = 0.035) and all-cause death (aHR: 1.699; 95% CI: 1.074–2.687; p = 0.023) were significantly higher in the female group than in the male group. At 2 years, the cumulative incidences of all-cause death (aHR: 1.561; 95% CI: 1.103–2.210; p = 0.012) and Re-MI (aHR: 1.880; 95% CI: 1.089–2.974; p = 0.022) were significantly higher in the female group than in the male group. However, the cumulative incidences of ST were similar between the two groups (aHR: 1.207; 95% CI: 0.583–2.497; p = 0.613). Conclusions: The female group showed worse short-term and long-term clinical outcomes compared with the male group comprised of Korean AMI patients with a history of current smoking after successful DES implantation. However, further studies are required to confirm these results

    ST-elevation versus non-ST-elevation myocardial infarction after combined use of statin with renin–angiotensin system inhibitor: Data from the Korea Acute Myocardial Infarction Registry

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    Background: Limited data are available comparing the combined effects of statins and renin–angiotensin system inhibitor (RASI) between patients with ST-segment elevation myocardial infarction (STEMI) and those with non-STEMI (NSTEMI). We compared the effects of statins combined with RASI in STEMI and NSTEMI patients after stent implantation during a long-term follow-up period. Methods: A total of 21,890 acute myocardial infarction (AMI) patients who underwent successful stent implantation and who received statins with RASI were enrolled. They were separated into the STEMI group (n = 12,490) and the NSTEMI group (n = 9400). The major clinical endpoint was the occurrence of major adverse cardiac events (MACEs) defined as all-cause death, recurrent myocardial infarction (Re-MI), and any repeat revascularization. Results: Two propensity score-matched (PSM) groups (5891 pairs, n = 11782, C-statistic = 0.821) were generated. Even though the cumulative incidences of MACE, re-MI, total repeat revascularization were similar between the two groups, the cumulative incidences of all-cause death (hazard ratio [HR] 1.407; 95% confidence interval [CI] 1.106–1.790; p = 0.005) and cardiac death (HR 1.311; 95% CI 1.983–1.749; p = 0.046) were significantly higher in the NSTEMI group. Conclusions: In this study, statin with RASI combination therapy was more beneficial to the STEMI patients than to the NSTEMI patients in reducing all-cause death and cardiac death

    Angiotensin converting enzyme inhibitors versus angiotensin II type 1 receptor blockers in patients with acute myocardial infarction and prediabetes after successful implantation of newer-generation drug-eluting stents

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    Background: Because limited data are available, the present study investigated 2-year major clinical outcomes after angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II type 1 receptor blockers (ARBs) therapy in patients with acute myocardial infarction (AMI) and prediabetes after successful implantation of newer-generation drug-eluting stents (DESs). Methods: Overall, 2932 patients with AMI and prediabetes were classified into two groups — the ACEIs group (n = 2059) and the ARBs group (n = 873). The primary endpoint was the occurrence of patient-oriented composite outcome (POCO), defined as all-cause death, recurrent myocardial infarction (Re-MI), or any repeat revascularization. The secondary endpoint was definite or probable stent thrombosis (ST). Results: The cumulative incidences of POCO (adjusted hazard ratio [aHR]: 1.020; 95% confidence interval [CI]: 0.740–1.404; p = 0.906), all-cause death (aHR: 1.394; 95% CI: 0.803–2.419; p = 0.238), Re-MI (aHR: 1.210; 95% CI: 0.626–2.340; p = 0.570), any repeat revascularization (aHR: 1.150; 95% CI: 0.713–1.855; p = 0.568), and ST (aHR: 1.736; 95% CI: 0.445–6.766; p = 0.427) were similar between the groups. These results were confirmed after propensity score-adjusted analysis. Conclusions: In this study, patients with AMI and prediabetes who received ACEIs or ARBs showed comparable clinical outcomes during the 2-year follow-up period

    Evaluation of a competitive ELISA for antibody detection against avian influenza virus

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    Active serologic surveillance is necessary to control the spread of the avian influenza virus (AIV). In this study, we evaluated a commercially-available cELISA in terms of its ability to detect AIV antibodies in the sera of 3,358 animals from twelve species. cELISA detected antibodies against reference H1- through H15-subtype AIV strains without cross reactivity. Furthermore, the cELISA was able to detect antibodies produced following a challenge of the AIV H9N2 subtype in chickens, or following vaccination of the AIV H9 or H5 subtypes in chickens, ducks and geese. Next, we tested the sensitivity and specificity of the cELISA with sera from twelve different animal species, and compared these results with those obtained by the hemagglutination-inhibition (HI) test, the "gold standard" in AIV sera surveillance, a second commercially-available cELISA (IZS ELISA), or the agar gel precipitation (AGP) test. Compared with the HI test, the sensitivities and specificities of cELISA were 95% and 96% in chicken, 86% and 88% in duck, 97% and 100% in turkey, 100% and 87% in goose, and 91% and 97% in swine, respectively. The sensitivities and specificities of the cELISA in this study were higher than those of IZS ELISA for the duck, turkey, goose, and grey partridge sera samples. The results of AGP test against duck and turkey sera also showed significant correlation with the results of cELISA (R-value >0.9). In terms of flock sensitivity, the cELISA correlated better with the HI test than with commercially-available indirect ELISAs, with 100% flock sensitivity
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