475 research outputs found

    Small-Scale structure in the Galactic ISM: Implications for Galaxy Cluster Studies

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    Observations of extragalactic objects need to be corrected for Galactic absorption and this is often accomplished by using the measured 21 cm HI column. However, within the beam of the radio telescope there are variations in the HI column that can have important effects in interpreting absorption line studies and X-ray spectra at the softest energies. We examine the HI and DIRBE/IRAS data for lines of sight out of the Galaxy, which show evidence for HI variations in of up to a factor of three in 1 degree fields. Column density enhancements would preferentially absorb soft X-rays in spatially extended objects and we find evidence for this effect in the ROSAT PSPC observations of two bright clusters of galaxies, Abell 119 and Abell 2142. For clusters of galaxies, the failure to include column density fluctuations will lead to systematically incorrect fits to the X-ray data in the sense that there will appear to be a very soft X-ray excess. This may be one cause of the soft X-ray excess in clusters, since the magnitude of the effect is comparable to the observed values.Comment: 16 pages, 9 figures, to appear in the Astrophysical Journal, vol. 597 (1 Nov 2003

    Effects of Local Blood Flow on Muscle Stiffness

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    Muscle injuries, in the form of strains or even tears, affect millions of people each year through undue tension on muscles during everyday activities, work tasks, or physical activity including sports or working out. These injuries can take from a few weeks to even months to heal, with patients having to deal with inflammation, swelling, and pain throughout the healing process. Scar tissue also forms when the muscle is injured, which regenerates throughout the healing process, but never fully recovers to its state prior to injury. This scar tissue is thought to make the muscle more prone to subsequent injury, making it important to avoid muscle injuries to begin with so as to not lose overall strength and range of motion. Although there are currently certain activities identified to increase the probability of muscle injury, there is limited evidence as to what physiological components may make an individual more susceptible to injury. Therefore, the purpose of this study is to look at the association between two measures; blood flow velocity through muscle using Doppler ultrasound and the muscle\u27s stiffness, or Young\u27s modulus, using ultrasound elastography. A notable correlation between the two factors could allow clinicians to know if patients have a predisposition to muscle injury due to their rate of blood flow

    Catatonia in Older Adult Individuals with Intellectual Disabilities

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    Catatonia has been described in children with intellectual disabilities (IDs). These are the first three published cases of catatonia in adults older than 50 years of age with IDs. They were followed using the KANNER scale and, in one case, creatinine phosphokinase (CPK) monitoring. Case 1 is a 67-year-old Caucasian who probably had been having intermittent episodes of undiagnosed catatonia withdrawal for many years. His episodes of agitation and withdrawal behavior responded to lorazepam up to 8 mg/day. Case 2 is a 63-year-old Caucasian male who had probably had undiagnosed catatonic episodes since age 25. An agitation episode that rated 88 on Part 2 of the KANNER scale ended within minutes after he received 1 mg of intramuscular lorazepam. He had no symptom relapses for 4 years after getting stable oral lorazepam doses (3-8.5 mg/day). Case 3 is a 55-year-old African-American male with severe ID and bradycardia (with a pacemaker). He had been institutionalized since age 22 and his undiagnosed catatonic episodes appeared to have been intermittently present for at least the last ten years. As he became tolerant and experienced symptom relapse, oral lorazepam was slowly increased (1.5-18 mg/day). Electroconvulsive therapy was ruled out due to his pacemaker

    FGF23 Synthesis and Activity

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    Purpose of review: The phosphaturic hormone FGF23 is produced primarily in osteoblasts/osteocytes and is known to respond to increases in serum phosphate and 1,25(OH)2 vitamin D (1,25D). Novel regulators of FGF23 were recently identified, and may help explain the pathophysiologies of several diseases. This review will focus on recent studies examining the synthesis and actions of FGF23. Recent findings: The synthesis of FGF23 in response to 1,25D is similar to other steroid hormone targets, but the cellular responses to phosphate remain largely unknown. The activity of intracellular processing genes control FGF23 glycosylation and phosphorylation, providing critical functions in determining the serum levels of bioactive FGF23. The actions of FGF23 largely occur through its co-receptor αKlotho (KL) under normal circumstances, but FGF23 has KL-independent activity during situations of high concentrations. Summary: Recent work regarding FGF23 synthesis and bioactivity, as well as considerations for diseases of altered phosphate balance will be reviewed

    Infants’ emotional and social experiences during and after the transition to early childhood education and care

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    The socio-emotional experiences of infants during transitions to early childhood education and care (ECEC) and across their first year in these out-of-home contexts are not well known. In an international project across five countries (New Zealand, Finland, Australia, Scotland and the United States), observational data, video of key moments, plus re-probing interviews with parents and teachers concerning 10 infants (six females) aged 5–13 months were collected across the first year of ECEC. An embedded case study design was used to analyse infant experiences from both quantitative and qualitative perspectives. Findings indicated low positive affect on infants’ first day of ECEC that increased after the first week and throughout the first year of ECEC. Drop-off periods remained a time of negative emotionality for the first month of ECEC. Over time more positive emotional experiences were evident, with peer interactions fostering positive affect, activeness and involvement, while one-on-one interactions with teachers were an important context for interpersonal engagement and well-being. These findings shed light on the highly charged emotional experience for infants when they transition to institutional care, and how these might be ameliorated in practice.peerReviewe

    Osteocytic FGF23 and Its Kidney Function

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    Osteocytes, which represent up to 95% of adult skeletal cells, are deeply embedded in bone. These cells exhibit important interactive abilities with other bone cells such as osteoblasts and osteoclasts to control skeletal formation and resorption. Beyond this local role, osteocytes can also influence the function of distant organs due to the presence of their sophisticated lacunocanalicular system, which connects osteocyte dendrites directly to the vasculature. Through these networks, osteocytes sense changes in circulating metabolites and respond by producing endocrine factors to control homeostasis. One critical function of osteocytes is to respond to increased blood phosphate and 1,25(OH)2 vitamin D (1,25D) by producing fibroblast growth factor-23 (FGF23). FGF23 acts on the kidneys through partner fibroblast growth factor receptors (FGFRs) and the co-receptor Klotho to promote phosphaturia via a downregulation of phosphate transporters, as well as the control of vitamin D metabolizing enzymes to reduce blood 1,25D. In the first part of this review, we will explore the signals involved in the positive and negative regulation of FGF23 in osteocytes. In the second portion, we will bridge bone responses with the review of current knowledge on FGF23 endocrine functions in the kidneys

    A Deep Look at the Emission-Line Nebula in Abell 2597

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    The close correlation between cooling flows and emission-line nebulae in clusters of galaxies has been recognized for over a decade and a half, but the physical reason for this connection remains unclear. Here we present deep optical spectra of the nebula in Abell 2597, one of the nearest strong cooling-flow clusters. These spectra reveal the density, temperature, and metal abundances of the line-emitting gas. The abundances are roughly half-solar, and dust produces an extinction of at least a magnitude in V. The absence of [O III] 4363 emission rules out shocks as a major ionizing mechanism, and the weakness of He II 4686 rules out a hard ionizing source, such as an active galactic nucleus or cooling intracluster gas. Hot stars are therefore the best candidate for producing the ionization. However, even the hottest O stars cannot power a nebula as hot as the one we see. Some other nonionizing source of heat appears to contribute a comparable amount of power. We show that the energy flux from a confining medium can become important when the ionization level of a nebula drops to the low levels seen in cooling-flow nebulae. We suggest that this kind of phenomenon, in which energy fluxes from the surrounding medium augment photoelectric heating, might be the common feature underlying the diverse group of objects classified as LINERS.Comment: 33 Latex pages, including 16 Postscript figures, to appear in 1997 September 1 Astrophysical Journa

    Independent large scale duplications in multiple M. tuberculosis lineages overlapping the same genomic region

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    Mycobacterium tuberculosis, the causative agent of most human tuberculosis, infects one third of the world's population and kills an estimated 1.7 million people a year. With the world-wide emergence of drug resistance, and the finding of more functional genetic diversity than previously expected, there is a renewed interest in understanding the forces driving genome evolution of this important pathogen. Genetic diversity in M. tuberculosis is dominated by single nucleotide polymorphisms and small scale gene deletion, with little or no evidence for large scale genome rearrangements seen in other bacteria. Recently, a single report described a large scale genome duplication that was suggested to be specific to the Beijing lineage. We report here multiple independent large-scale duplications of the same genomic region of M. tuberculosis detected through whole-genome sequencing. The duplications occur in strains belonging to both M. tuberculosis lineage 2 and 4, and are thus not limited to Beijing strains. The duplications occur in both drug-resistant and drug susceptible strains. The duplicated regions also have substantially different boundaries in different strains, indicating different originating duplication events. We further identify a smaller segmental duplication of a different genomic region of a lab strain of H37Rv. The presence of multiple independent duplications of the same genomic region suggests either instability in this region, a selective advantage conferred by the duplication, or both. The identified duplications suggest that large-scale gene duplication may be more common in M. tuberculosis than previously considere

    Fish Health Unit Report of Activities Undertaken in 2023

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    This report summarises the activities undertaken by the Fish Health Unit of the Marine Institute in 2023. Regulation (EU) 2016/429 lays down the rules for the prevention and control of animal diseases which are transmissible to animal or humans and the Marine Institute is the Competent Authority responsible for implementation of this regulation in Ireland. The purpose of this report is to provide all stakeholders with an improved understanding of the operations of the Marine Institute in fish health, and the findings encountered by the Fish Health Unit in 2023.Marine Institut

    Increased FGF23 protects against detrimental cardio-renal consequences during elevated blood phosphate in CKD

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    The phosphaturic hormone FGF23 is elevated in chronic kidney disease (CKD). The risk of premature death is substantially higher in the CKD patient population, with cardiovascular disease (CVD) as the leading mortality cause at all stages of CKD. Elevated FGF23 in CKD has been associated with increased odds for all-cause mortality; however, whether FGF23 is associated with positive adaptation in CKD is unknown. To test the role of FGF23 in CKD phenotypes, a late osteoblast/osteocyte conditional flox-Fgf23 mouse (Fgf23fl/fl/Dmp1-Cre+/-) was placed on an adenine-containing diet to induce CKD. Serum analysis showed casein-fed Cre+ mice had significantly higher serum phosphate and blood urea nitrogen (BUN) versus casein diet and Cre- genotype controls. Adenine significantly induced serum intact FGF23 in the Cre- mice over casein-fed mice, whereas Cre+ mice on adenine had 90% reduction in serum intact FGF23 and C-terminal FGF23 as well as bone Fgf23 mRNA. Parathyroid hormone was significantly elevated in mice fed adenine diet regardless of genotype, which significantly enhanced midshaft cortical porosity. Echocardiographs of the adenine-fed Cre+ hearts revealed profound aortic calcification and cardiac hypertrophy versus diet and genotype controls. Thus, these studies demonstrate that increased bone FGF23, although associated with poor outcomes in CKD, is necessary to protect against the cardio-renal consequences of elevated tissue phosphate
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