2,358 research outputs found

    Kinematic study of planetary nebulae in NGC 6822

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    By measuring precise radial velocities of planetary nebulae (which belong to the intermediate age population), H II regions, and A-type supergiant stars (which are members of the young population) in NGC 6822, we aim to determine if both types of population share the kinematics of the disk of H I found in this galaxy. Spectroscopic data for four planetary nebulae were obtained with the high spectral resolution spectrograph Magellan Inamori Kyocera Echelle (MIKE) on the Magellan telescope at Las Campanas Observatory. Data for other three PNe and one H II region were obtained from the SPM Catalog of Extragalactic Planetary Nebulae which employed the Manchester Echelle Spectrometer attached to the 2.1m telescope at the Observatorio Astron\'omico Nacional, M\'exico. In the wavelength calibrated spectra, the heliocentric radial velocities were measured with a precision better than 5-6 km s1^{-1}. Data for three additional H II regions and a couple of A-type supergiant stars were collected from the literature. The heliocentric radial velocities of the different objects were compared to the velocities of the H i disk at the same position. From the analysis of radial velocities it is found that H II regions and A-type supergiants do share the kinematics of the H I disk at the same position, as expected for these young objects. On the contrary, planetary nebula velocities differ significantly from that of the H I at the same position. The kinematics of planetary nebulae is independent from the young population kinematics and it is closer to the behavior shown by carbon stars, which are intermediate-age members of the stellar spheroid existing in this galaxy. Our results are confirming that there are at least two very different kinematical systems in NGC 6822

    Brucella neotomae Infection in Humans, Costa Rica

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    Several species of Brucella are known to be zoonotic, but B. neotomae infection has been thought to be limited to wood rats. In 2008 and 2011, however, B. neotomae was isolated from cerebrospinal fluid of 2 men with neurobrucellosis. The nonzoonotic status of B. neotomae should be reassessed

    Moving beyond disrespect and abuse: addressing the structural dimensions of obstetric violence

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    AbstractDuring recent decades, a growing and preoccupying excess of medical interventions during childbirth, even in physiological and uncomplicated births, together with a concerning spread of abusive and disrespectful practices towards women during childbirth across the world, have been reported. Despite research and policy-making to address these problems, changing childbirth practices has proved to be difficult. We argue that the excessive rates of medical interventions and disrespect towards women during childbirth should be analysed as a consequence of structural violence, and that the concept of obstetric violence, as it is being used in Latin American childbirth activism and legal documents, might prove to be a useful tool for addressing structural violence in maternity care such as high intervention rates, non-consented care, disrespect and other abusive practices

    Sustainable sugarcane vinasse biorefinement for trans-aconitic acid-based biopolymer synthesis and bioenergy generation

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    This study aimed at developing a multiproduct biorefinery scheme for vinase valorization. It involved the extraction of trans-aconitic acid, its transformation into biopolymers using microwave irradiation and the use of the raffinated-vinasse for biogas production. Each technology was assessed individually, followed by a process integration at bench scale, from which a mass balance was calculated, supporting the feasibility of the approach. As a renewable source derived from a residue, these bioproducts can replace crude-oil-based materials in various chemical industrial processes; however, a detailed techno-economic and life-cycle analysis are required to defined the sustainability of the process

    A Method for Combining Isolates of Phytophthora sojae to Screen for Novel Sources of Resistance to Phytophthora Stem and Root Rot in Soybean

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    Soybean cultivars with specific single resistance genes (Rps) are grown to reduce yield loss due to Phytophthora stem and root rot caused by the oomycete pathogen Phytophthora sojae. To identify novel Rps loci, soybean lines are often screened several times, each time with an isolate of P. sojae that differs in virulence on various Rps genes. The goal of this study was to determine whether several isolates of P. sojae that differ in virulence on Rpsgenes could be combined into a single source of inoculum and used to screen soybean lines for novel Rps genes. A set of 14 soybean differential lines, each carrying a specific Rps gene, was inoculated with three isolates of P. sojae, which differed in virulence on 6 to 10 Rps genes, individually or in a 1:1:1 mixture. Inoculum containing the 1:1:1 mixture of isolates was virulent on 13 Rps genes. The mixed-inoculum method was used to screen 1,019 soybean accessions in a blind assay for novel sources of resistance. In all, 17% of Glycine max accessions and 11% of G. soja accessions were resistant (≤30% dead plants), suggesting that these accessions may carry a novel Rps gene or genes. Advantages of combining isolates into a single source of inoculum include reduced cost, ability to screen soybean germplasm with inoculum virulent on all known Rps genes, and ease of identifying novel sources of resistance. This study is a precursor to identifying novel sources of resistance to P. sojae in soybean using RXLR effectors

    ISG15 and ISGylation is required for pancreatic cancer stem cell mitophagy and metabolic plasticity

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    Pancreatic cancer stem cells (PaCSCs) drive pancreatic cancer tumorigenesis, chemoresistance and metastasis. While eliminating this subpopulation of cells would theoretically result in tumor eradication, PaCSCs are extremely plastic and can successfully adapt to targeted therapies. In this study, we demonstrate that PaCSCs increase expression of interferon-stimulated gene 15 (ISG15) and protein ISGylation, which are essential for maintaining their metabolic plasticity. CRISPR-mediated ISG15 genomic editing reduces overall ISGylation, impairing PaCSCs self-renewal and their in vivo tumorigenic capacity. At the molecular level, ISG15 loss results in decreased mitochondrial ISGylation concomitant with increased accumulation of dysfunctional mitochondria, reduced oxidative phosphorylation (OXPHOS) and impaired mitophagy. Importantly, disruption in mitochondrial metabolism affects PaCSC metabolic plasticity, making them susceptible to prolonged inhibition with metformin in vivo. Thus, ISGylation is critical for optimal and efficient OXPHOS by ensuring the recycling of dysfunctional mitochondria, and when absent, a dysregulation in mitophagy occurs that negatively impacts PaCSC stemness

    A genetic case-control study confirms the implication of SMAD7 and TNF locus in the development of proliferative vitreoretinopathy

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    PURPOSE: Proliferative vitreoretinopathy (PVR) is still the major cause of failure of retinal detachment (RD) surgery and although the risk for developing this complication is associated with some clinical characteristics, the correlation is far from absolute, raising the possibility of genetic susceptibility. The objective of this study was to analyze the genetic contribution to PVR in patients undergoing RD surgery, the Retina 4 Project. METHODS: A candidate gene association study was conducted in 2006 in a Spanish population of 450 patients suffering from primary rhegmatogenous RD. Replication was carried out in a larger population undergoing RD surgery at several European centers among 546 new patients. Single nucleotide polymorphism (SNP) of 30 genes known to be involved with inflammation were analyzed. For replication stage, those genes previously detected as significantly associated with PVR were genotyped. Distribution of allelic and haplotypic frequencies in case and control group were analyzed. Single and haplotypic analysis were assessed. The Rosenberg two-stage method was used to correct for single and multiple analyses. RESULTS: After correction for multiple comparisons, four genes were significantly associated with PVR: SMAD7 (P = 0.004), PIK3CG (P = 0.009), TNF locus (P = 0.0005), and TNFR2 (P = 0.019) In the European sample, replication was observed in SMAD7 (P = 0.047) and the TNF locus (P = 0.044). CONCLUSIONS: These results confirm the genetic contribution to PVR and the implication of SMAD7 and TNF locus in the development of PVR. This finding may have implications for understanding the mechanisms of PVR and could provide a potential new therapeutic target for PVR prophylaxis
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