488 research outputs found
A New Sub-Period-Minimum Cataclysmic Variable With Partial Hydrogen Depletion And Evidence Of Spiral Disk Structure
We present time-resolved spectroscopy and photometry of CSS 120422:111127+571239 (=SBS 1108+574), a recently discovered SU UMa-type dwarf nova whose 55 minute orbital period is well below the cataclysmic variable (CV) period minimum of similar to 78 minutes. In contrast with most other known CVs, its spectrum features He I emission of comparable strength to the Balmer lines, implying a hydrogen abundance less than 0.1 of long-period CVs-but still at least 10 times higher than that in AM CVn stars. Together, the short orbital period and remarkable helium-to-hydrogen ratio suggest that mass transfer in CSS 120422 began near the end of the donor star's main-sequence lifetime, meaning that this CV is a strong candidate progenitor of an AM CVn system as described by Podsiadlowski et al. Moreover, a Doppler tomogram of the Ha line reveals two distinct regions of enhanced emission. While one is the result of the stream-disk impact, the other is probably attributable to spiral disk structure generated when material in the outer disk achieves a 2:1 orbital resonance with respect to the donor.NSF AST-1211196, AST-9987045Department of Physics at the University of Notre DameNSF Telescope System Instrumentation Program (TSIP)Ohio Board of RegentsOhio State University Office of ResearchAstronom
Intraventricular Thrombi with Systemic Embolization: Two Clinical Cases
A formação de trombos intraventriculares é um complicação frequente nos doentes com miocardiopatia dilatada e enfarte agudo do miocárdio, sendo o risco de embolização sistémica muito variável em função da patologia subjacente e características subjacentes dos trombos. Os autores descrevem dois casos clínicos relativos a dois doentes internados no mesmo dia com trombos intraventriculares, volumosos, protuberantes e muito móveis, no contexto de miocardiopatia dilatada e enfarte agudo do miocárdio, que embolizaram para os membros inferiores. Salientam a importância da ecocardiografia no diagnóstico, caracterização morfológica inicial e controlo evolutivo dos trombos intraventriculares, aspectos fundamentais na avaliação do risco embólico. Na ausência de recomendações específicas quanto às opções terapêuticas – anticoagulação, trombólise ou remoção cirúrgica, os autores sublinham a necessidade de avaliação individualizada, «caso a caso», tendo em conta o risco embólico, hemorrágico, e cirúrgico
Concomitant pulmonary embolism and aortic dissection: approach to anticoagulation
Os autores descrevem um caso de uma doente admitida após episódio pré-sincopal
associado a precordialgia e cujo ecocardiograma sumário feito no Servic¸o de Urgência demonstrou alterac¸ões compatíveis com tromboembolismo pulmonar, tendo a doente sido submetida
a terapêutica fibrinolítica, após episódio de paragem cardiorrespiratória. Na angiotomografia
de tórax feita posteriormente para confirmac¸ão diagnóstica demonstra-se a presenc¸a não só de
trombos no nível da artéria pulmonar, mas também de dissec¸ão da aorta Stanford B, tendo-se
optado pela manutenc¸ão de anticoagulac¸ão terapêutica e a doente evoluído de forma favorável.The authors describe a case of a patient admitted with a pre-syncopal episode and precordial discomfort, and whose cardiac ultrasound performed in the Emergency Room was suggestive of Pulmonary Embolism. The patient was submitted to fibrinolytic therapy after cardiac arrest. The computerized tomography done after this episode not only confirmed the presence of pulmonary embolism but had also shown a Stanford Type B Aortic Dissection. The option was to maintain the therapeutic anticoagulation, having the patient evolved favourably.info:eu-repo/semantics/publishedVersio
Trombos intraventriculares com embolização sistémica: a propósito de dois casos clínicos
A formação de trombos intraventriculares é
um complicação frequente nos doentes com
miocardiopatia dilatada e enfarte agudo do
miocárdio, sendo o risco de embolização
sistémica muito variável em função da
patologia subjacente e características
subjacentes dos trombos. Os autores
descrevem dois casos clínicos relativos a dois doentes internados no mesmo dia com
trombos intraventriculares, volumosos,
protuberantes e muito móveis, no contexto de
miocardiopatia dilatada e enfarte agudo do
miocárdio, que embolizaram para os membros inferiores. Salientam a importância da ecocardiografia no diagnóstico, caracterização morfológica inicial e controlo evolutivo dos trombos intraventriculares, aspectos fundamentais na avaliação do risco embólico. Na ausência de recomendações específicas quanto às opções terapêuticas – anticoagulação, trombólise ou remoção cirúrgica, os autores sublinham a necessidade de avaliação individualizada, «caso a caso», tendo em conta o risco embólico, hemorrágico, e cirúrgico
The relationship between alcohol consumption and dry eye
Purpose: To assess the association between dry eye disease (DED) and alcohol consumption using a large population-based cohort. Methods: 77,145 participants (19-94 years, 59% female) from the Dutch Lifelines cohort were cross-sectionally assessed for DED using the Women's Health Study (WHS) dry eye questionnaire. Alcohol intake was assessed using self-reported food frequency questionnaires. The relationship between DED and alcohol use was analyzed using logistic regression, corrected for age, sex, BMI, smoking status, education, income, and 55 potentially confounding comorbidities. Results: Overall, 30.0% of participants had symptomatic dry eye. Alcohol use significantly increased the risk of symptomatic dry eye in females (odds ratio [OR] 1.095, 95%CI 1.045-1.148), but not in males (OR 0.988, 95%CI 0.900-1.084). Contrarily, in male drinkers, increasing alcohol intake (in 10 g/day) had a protective effect on symptomatic dry eye (OR 0.962, 95%CI 0.934-0.992), which was not seen in females (OR 0.986, 95%CI 0.950-1.023). Alcohol use and intake had a sex-specific effect on all outcomes of DED assessed: symptomatic dry eye, highly symptomatic dry eye, clinical diagnosis, and WHS definition dry eye. Conclusions: This large population-based study found alcohol use to have a clear sex-specific effect on DED, presenting as a risk-factor only in females. This adds to the evidence of sex-specific pathophysiological mechanisms of dry eye and illustrates the importance of sex stratification in studies investigating DED. The mild protective effect of increased alcohol intake in male drinkers is advised to be interpreted with caution, as alcohol's other health effects might be of greater clinical significance
Influence of Nanoparticle Size and Shape on Oligomer Formation of an Amyloidogenic Peptide
Understanding the influence of macromolecular crowding and nanoparticles on
the formation of in-register -sheets, the primary structural component
of amyloid fibrils, is a first step towards describing \emph{in vivo} protein
aggregation and interactions between synthetic materials and proteins. Using
all atom molecular simulations in implicit solvent we illustrate the effects of
nanoparticle size, shape, and volume fraction on oligomer formation of an
amyloidogenic peptide from the transthyretin protein. Surprisingly, we find
that inert spherical crowding particles destabilize in-register -sheets
formed by dimers while stabilizing -sheets comprised of trimers and
tetramers. As the radius of the nanoparticle increases crowding effects
decrease, implying smaller crowding particles have the largest influence on the
earliest amyloid species. We explain these results using a theory based on the
depletion effect. Finally, we show that spherocylindrical crowders destabilize
the ordered -sheet dimer to a greater extent than spherical crowders,
which underscores the influence of nanoparticle shape on protein aggregation
AVC isquémico pericateterismo cardíaco: a propósito de um caso clínico
O AVC isquémico ocorre em 0,2 a 0,4%
dos doentes submetidos a cateterização
cardíaca esquerda, sendo responsável
por 5-10% da mortalidade relacionada com o
procedimento. Estão identificados alguns
factores predisponentes para esta complicação como sejam o sexo feminino,
a presença de placas de aterosclerose
complexas na aorta ascendente e/ou de doença arterial periférica. A oportunidade de intervenção dentro da janela de reperfusão reforça a estratégia de uma
vigilância clínica rigorosa no período imediato pós-cateterização. O Cardiologista deve estar bem familiarizado com as diferentes modalidades da terapêutica de reperfusão e suas indicações de acordo com a relação temporal do AVC isquémico com o cateterismo, devendo essa decisão ser partilhada com a Neurologia e Neuro-radiologia
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