277 research outputs found
Herschel imaging and spectroscopy of the nebula around the luminous blue variable star WRAY 15-751
We have obtained far-infrared Herschel PACS imaging and spectroscopic
observations of the nebular environment of the luminous blue variable WRAY
15-751. These images clearly show that the main, dusty nebula is a shell of
radius 0.5 pc and width 0.35 pc extending outside the H-alpha nebula. They also
reveal a second, bigger and fainter dust nebula, observed for the first time.
Both nebulae lie in an empty cavity, likely the remnant of the O-star wind
bubble formed when the star was on the main sequence. The kinematic ages of the
nebulae are about 20000 and 80000 years and each nebula contains about 0.05
Msun of dust. Modeling of the inner nebula indicates a Fe-rich dust. The
far-infrared spectrum of the main nebula revealed forbidden emission lines
coming from ionized and neutral gas. Our study shows that the main nebula
consists of a shell of ionized gas surrounded by a thin photodissociation
region illuminated by an "average" early-B star. The derived abundance ratios
N/O=1.0+/-0.4 and C/O=0.4+/-0.2 indicate a mild N/O enrichment. We estimate
that the inner shell contains 1.7+/-0.6 Msun of gas. Assuming a similar
dust-to-gas ratio for the outer nebula, the total mass ejected by WRAY 15-751
amounts to 4+/-2 Msun. The measured abundances, masses and kinematic ages of
the nebulae were used to constrain the evolution of the star and the epoch at
which the nebulae were ejected. Our results point to an ejection of the nebulae
during the RSG evolutionary phase of an ~ 40 Msun star. The presence of
multiple shells around the star suggests that the mass-loss was not a
continuous ejection but rather a series of episodes of extreme mass-loss. Our
measurements are compatible with the recent evolutionary tracks computed for an
40 Msun star with little rotation. They support the O-BSG-RSG-YSG-LBV filiation
and the idea that high-luminosity and low-luminosity LBVs follow different
evolutionary paths.Comment: 19 pages, 13 figures, accepted for publication in A&
The Herschel view of the nebula around the luminous blue variable star AG Carinae
Far-infrared Herschel PACS imaging and spectroscopic observations of the
nebula around the luminous blue variable (LBV) star AG Car have been obtained
along with optical imaging in the Halpha+[NII] filter. In the infrared light,
the nebula appears as a clumpy ring shell that extends up to 1.2 pc with an
inner radius of 0.4 pc. It coincides with the Halpha nebula, but extends
further out. Dust modeling of the nebula was performed and indicates the
presence of large grains. The dust mass is estimated to be ~ 0.2 Msun. The
infrared spectrum of the nebula consists of forbidden emission lines over a
dust continuum. Apart from ionized gas, these lines also indicate the existence
of neutral gas in a photodissociation region that surrounds the ionized region.
The abundance ratios point towards enrichment by processed material. The total
mass of the nebula ejected from the central star amounts to ~ 15 Msun, assuming
a dust-to-gas ratio typical of LBVs. The abundances and the mass-loss rate were
used to constrain the evolutionary path of the central star and the epoch at
which the nebula was ejected, with the help of available evolutionary models.
This suggests an ejection during a cool LBV phase for a star of ~ 55 Msun with
little rotation.Comment: accepted for publication in A&
Herschel observations of nebulae ejected by massive evolved stars
We have obtained far-infrared Herschel PACS imaging and spectroscopic observations of nebulae associated to massive evolved stars. The study of these nebulae is crucial to understand the evolution of these stars as it can reveal the mass-loss history.
The infrared images along with available data at other wavelengths give a complete view of their morphology. The dust modeling provides the dust parameters, such as the temperature, the mass and the composition of dust. The spectroscopic analysis provides the gas C,N,O abundances and mass. Based on these observations, the evolutionary status of the star at the time of the nebula ejection can be constrained.
We present here selected results of an ongoing exhaustive study of nebulae around low- and high-luminosity LBVs (AG Car, HR Car, WRAY 15-751, G79.29+0.46, HD168625), WN stars (NGC6888, M1-67, He3-519) and Of stars (NGC6164/5)
Wear and corrosion interactions on titanium in oral environment : literature review
The oral cavity is a complex environment where corrosive substances from dietary, human saliva, and oral biofilms may accumulate in retentive areas of dental implant systems and prostheses promoting corrosion at their surfaces. Additionally, during mastication, micromovements may occur between prosthetic joints causing a relative motion between contacting surfaces, leading to wear. Both processes (wear and corrosion) result in a bio-tribocorrosion system once that occurs in contact with biological tissues and fluids. This review paper is focused on the aspects related to the corrosion and wear behavior of titanium-based structures in the oral environment. Furthermore, the clinical relevance of the oral environment is focused on the harmful effect that acidic substances and biofilms, formed in human saliva, may have on titanium surfaces. In fact, a progressive degradation of titanium by wear and corrosion (tribocorrosion) mechanisms can take place affecting the performance of titanium-based implant and prostheses. Also, the formation of wear debris and metallic ions due to the tribocorrosion phenomena can become toxic for human tissues. This review gathers knowledge from areas like materials sciences, microbiology, and dentistry contributing to a better understanding of bio-tribocorrosion processes in the oral environment.(undefined
The view of teachers on bullying and implications for nursing
Objetivo: Compreender o bullying escolar,
na perspectiva dos professores, e refletir
sobre as possíveis ações da área da saúde
em seu enfrentamento. Para tanto, tomaram-
se por base as diretrizes do Programa
Saúde na Escola, dos Ministérios da Saúde
e da Educação. Método: Estudo de caso
qualitativo, realizado com professores de
uma escola pública de Minas Gerais. Foram
utilizados grupos focais na coleta de dados
e o material empírico foi decodificado
a partir de técnica de análise temática de
conteúdo, resultando em uma categoria
analítica: concepções e experiências de
professores diante do bullying. Resultados:
Foram identificadas percepções pontuais
sobre o fenômeno e utilização de recursos
de intervenção pouco eficazes. No plano
interpretativo, problematizaram-se as contribuições
da saúde e da enfermagem no
redimensionamento das intervenções e no
processo de formação continuada dos professores.
Conclusão: Os resultados apontam
para a construção de práticas intersetoriais
para o enfrentamento do bullying.To understand school bullying from the perspective of teachers and reflect about the possible actions of the health area when coping with it. The guidelines of the School Health Program of the Ministries of Health and Education were used to reach that purpose. Method: A qualitative study carried out with teachers of a public school in Minas Gerais. Focus groups were used to collect data and the empirical material was decoded from thematic analysis of content, resulting in an analytical category: conceptions and experiences of teachers on bullying. Results: Specific perceptions about the phenomenon and the use of ineffective intervention resources were identified. In the interpretive plan were problematized the health and nursing contributions with resizing the interventions and the continuing training process of teachers. Conclusion: The results point to the construction of intersectoral practices forcoping with bullying.Objetivo: Comprender el bullying escolar
desde la perspectiva de los profesores,
y reflexionar sobre las posibles acciones
del área de salud en su enfrentamiento.
Tomando como base los lineamientos del
Programa de Salud Escolar, de los Ministerios
de Salud y de Educación. Método:
Estudio de caso cualitativo realizado con
los profesores de una escuela pública en
Minas Gerais. Para la recolección de datos
se utilizaron grupos focales y el material
empírico fue decodificado a partir de la
técnica de análisis temático de contenido,
dando lugar a una categoría analítica: concepciones
y experiencias de los profesores
sobre el acoso escolar. Resultados: Se identificaron
percepciones específicas sobre el
fenómeno y la utilización de recursos ineficaces
de intervención. En el plano interpretativo,
se problematizaron las contribuciones
de la salud y de la enfermería en el
redimensionamiento de las intervenciones
y en el proceso de formación continua de
los profesores. Conclusión: Los resultados
apuntan a la construcción de prácticas intersectoriales
para el enfrentamiento del
bullying.CIEC - Centro de Investigação em Estudos da Criança, UM (UI 317 da FCT
Autoimmune gastrointestinal complications in patients with Systemic Lupus Erythematosus: case series and literature review
The association of systemic lupus erythematosus (SLE) with gastrointestinal autoimmune diseases is rare, but has been described in the literature, mostly as case reports. However, some of these diseases may be very severe, thus a correct and early diagnosis with appropriate management are fundamental. We have analysed our data from the SLE patient cohort at University College Hospital London, established in 1978, identifying those patients with an associated autoimmune gastrointestinal disease. We have also undertaken a review of the literature describing the major autoimmune gastrointestinal pathologies which may be coincident with SLE, focusing on the incidence, clinical and laboratory (particularly antibody) findings, common aetiopathogenesis and complications
Safety and efficacy of high-dose enteral, intravenous, and transdermal clonidine for the acute management of severe intractable childhood dystonia and status dystonicus:an illustrative case-series
Objective: Acute dystonia in children is distressing, painful and can progress to life-threatening status dystonicus. Typical management involves benzodiazepines which can result in respiratory depression requiring PICU admission. Clonidine is less respiratory-depressant, and by facilitating sleep, switches dystonia off. It can also be administered via enteral, continuous intravenous infusion, and transdermal slow release routes. We describe the dose range and safety profile of clonidine treatment in a case-series of children with severe acute exacerbation of dystonia in a tertiary hospital setting. Methods: The management of 5 children (3 female, age range 8-14 years) suffering from an acute exacerbation of secondary dystonia requiring hospital admission at the Evelina London Children’s Hospital was reviewed. The average and maximum dose of clonidine in mcg/kg/hr and routes of administration were recorded for each day of hospital admission. Co-administration of any other medical treatments for dystonia and their route of administration were also recorded. Cardiovascular and respiratory clinical status were measured by recording the daily mean and maximum Paediatric Early Warning Scores (PEWS). Results: Clonidine was administered via enteral, intravenous, and transdermal routes at a median dose of 2.5mcg/kg/hr (range 0.1 to 9 mcg/kg/hr). Administration of high dose clonidine was associated with decreased use of benzodiazepines, morphine, and propofol: avoiding invasive respiratory support for ¾ cases during admission. Clonidine doses via all routes of administration did not correlate with poorer PEWS scores (p=0.839).Both high dose intravenous and transdermal clonidine where found to be effective. Conclusions: High dose clonidine administered via different routes can be used in the acute management of severe exacerbations of dystonia. Its use in our cohort was not associated with significant cardio-respiratory depression even at doses as high as 9 mcg/kg/hr
Right drug, right patient, right time: aspiration or future promise for biologics in rheumatoid arthritis?
Individualising biologic disease-modifying anti-rheumatic drugs (bDMARDs) to maximise outcomes and deliver safe and cost-effective care is a key goal in the management of rheumatoid arthritis (RA). Investigation to identify predictive tools of bDMARD response is a highly active and prolific area of research. In addition to clinical phenotyping, cellular and molecular characterisation of synovial tissue and blood in patients with RA, using different technologies, can facilitate predictive testing. This narrative review will summarise the literature for the available bDMARD classes and focus on where progress has been made. We will also look ahead and consider the increasing use of ‘omics’ technologies, the potential they hold as well as the challenges, and what is needed in the future to fully realise our ambition of personalised bDMARD treatment
RBCK1‐related disease: A rare multisystem disorder with polyglucosan storage, auto‐inflammation, recurrent infections, skeletal, and cardiac myopathy—Four additional patients and a review of the current literature
In this article, we report four new patients, from three kindreds, with pathogenic variants in RBCK1 and a multisystem disorder characterised by widespread polyglucosan storage. We describe the clinical presentation of progressive skeletal and cardiac myopathy, combined immunodeficiencies and auto‐inflammation, illustrate in detail the histopathological findings in multiple tissue types, and report muscle MRI findings
Identification of Novel Inhibitors of Dietary Lipid Absorption Using Zebrafish
Pharmacological inhibition of dietary lipid absorption induces favorable changes in serum lipoprotein levels in patients that are at risk for cardiovascular disease and is considered an adjuvant or alternative treatment with HMG-CoA reductase inhibitors (statins). Here we demonstrate the feasibility of identifying novel inhibitors of intestinal lipid absorption using the zebrafish system. A pilot screen of an unbiased chemical library identified novel compounds that inhibited processing of fluorescent lipid analogues in live zebrafish larvae. Secondary assays identified those compounds suitable for testing in mammals and provided insight into mechanism of action, which for several compounds could be distinguished from ezetimibe, a drug used to inhibit cholesterol absorption in humans that broadly inhibited lipid absorption in zebrafish larvae. These findings support the utility of zebrafish screening assays to identify novel compounds that target complex physiological processes
- …
