26 research outputs found

    Nucleons or diquarks? Competition between clustering and color superconductivity in quark matter

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    We study the instabilities of quark matter in the framework of a generalized Nambu--Jona-Lasinio model, in order to explore possible competition between three-quark clustering to form nucleons and diquark formation leading to color superconductivity. Nucleon and Δ\Delta solutions are obtained for the relativistic Faddeev equation at finite density and their binding energies are compared with those for the scalar and axial-vector diquarks found from the Bethe-Salpeter equation. In a model with interactions in both scalar and axial diquark channels, bound nucleons exist up to nuclear matter density. However, except at densities below about a quarter of that of nuclear matter, we find that scalar diquark formation is energetically favored. This raises the question of whether a realistic phase diagram of baryonic matter can be obtained from any model which does not incorporate color confinement.Comment: 23 pages (RevTeX), 5 figures (epsf

    A Survey of University Students’ Preferences for Midwifery Care and Community Birth Options in 8 High‐Income Countries

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    Background: Midwifery care is associated with positive birth outcomes, access to community birth options, and judicious use of interventions. The aim of this study was to characterize and compare maternity care preferences of university students across a range of maternity care systems and to explore whether preferences align with evidence- based recommendations and options available. Methods: A cross-sectional, web-based survey was completed in 2014-2015 by a convenience sample of university students in 8 high-income countries across 4 continents (n=4,569). In addition to describing preferences for midwifery care and community birth options across countries, socio-demographic characteristics, psychological factors, knowledge about pregnancy and birth, and sources of information that shaped students’ attitudes towards birth were examined in relation to preferences for midwifery care and community birth options. Results: Approximately half of the student respondents (48. 2%) preferred midwifery-led care for a healthy pregnancy, 9.5% would choose to birth in a birthing center, and 4.5% preferred a home birth. Preference for midwifery care varied from 10.3% among women in the United States to 78.6% among women in England. Preferences for home birth varied from 0.3% among US women to 18.3% among Canadian women. Women, health science students, those with low childbirth fear, who learned about pregnancy and birth from friends (compared to other sources, e.g. the media) and those who responded from Europe were significantly more likely to prefer midwifery care and community birth. High confidence in knowledge of pregnancy and birth was linked to significantly higher odds of community birth preferences and midwifery care preferences Conclusions: It would be beneficial to integrate childbirth education into high school curricula, to promote knowledge of midwifery care, pregnancy and childbirth and reduce fear among prospective parents. Community birth options need to be expanded, to meet demand among the next generation of maternity service users

    Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

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    Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≄18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

    Comparison of attenuated and virulent West Nile virus strains in human monocyte-derived dendritic cells as a model of initial human infection

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    Background: The human-pathogenic North American West Nile virus strain (WNVNY99), responsible for the outbreak in New York city in 1999, has caused 41000 infections and 1739 human deaths to date. A new strain of West Nile virus emerged in New South Wales, Australia in 2011 (WNVNSW2011), causing a major encephalitic outbreak in horses with close to 1000 cases and 10-15% mortality. Unexpectedly, no human cases have so far been documented

    A survey of university students’ preferences for midwifery care and community birth options in 8 high‐income countries

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    Introduction Midwifery care is associated with positive birth outcomes, access to community birth options, and judicious use of interventions. The aim of this study was to characterize and compare maternity care preferences of university students across a range of maternity care systems and to explore whether preferences align with evidence‐based recommendations and options available. Methods A cross‐sectional, web‐based survey was completed in 2014 and 2015 by a convenience sample of university students in 8 high‐income countries across 4 continents (N = 4569). In addition to describing preferences for midwifery care and community birth options across countries, this study examined sociodemographic characteristics, psychological factors, knowledge about pregnancy and birth, and sources of information that shaped students’ attitudes toward birth in relation to preferences for midwifery care and community birth options. Results Approximately half of the student respondents (48.2%) preferred midwifery‐led care for a healthy pregnancy; 9.5% would choose to give birth in a birthing center, and 4.5% preferred a home birth. Preference for midwifery care varied from 10.3% among women in the United States to 78.6% among women in the United Kingdom. Preferences for home birth varied from 0.3% among US women to 18.3% among Canadian women. Women, health science students, those with low childbirth fear, those who learned about pregnancy and birth from friends (compared with other sources, eg, the media), and those who responded from Europe were significantly more likely to prefer midwifery care and community birth. High confidence in knowledge of pregnancy and birth was linked to significantly higher odds of community birth preferences and midwifery care preferences. Discussion It would be beneficial to integrate childbirth education into high school curricula to promote knowledge of midwifery care, pregnancy, and childbirth and to reduce fear among prospective parents. Community birth options need to be expanded to meet demand among the next generation of maternity service users

    West Nile virus NS2A protein facilitates virus-induced apoptosis independently of interferon response

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    The flavivirus NS2A protein is a small, multifunctional protein, involved in replication, virion formation and regulation of the innate immune response. Using the Kunjin strain of West Nile virus (WNVKUN) we previously demonstrated that a single amino acid change from alanine to proline at position 30 of the NS2A protein (A30P) reduced viral cytopathicity in cells and virulence in mice. To further investigate functions of the NS2A protein we have substituted alanine at position 30 with different amino acids (A30 mutants) in a WNVKUN infectious clone. The virulence of mutant viruses in wild-type (WT) and IRF3/IRF7 double-knockout mice was influenced by the amino acid change and ranged from high to low in the order of WT>A30L>A30E>A30P/A30G. Moreover, infection of beta interferon (IFN-ÎČ)-deficient Vero cells with A30P virus showed less pronounced chromosomal DNA degradation and lower percentage of cells with positive TUNEL labelling than in WT virus infection, indicating a role for the WT NS2A protein in IFN-independent apoptotic cell death

    Systematic analysis of viral genes responsible for differential virulence between American and Australian West Nile virus strains

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    A variant Australian West Nile virus (WNV) strain, WNVNSW2011, emerged in 2011 causing an unprecedented outbreak of encephalitis in horses in south-eastern Australia. However, no human cases associated with this strain have yet been reported. Studies using mouse models for WNV pathogenesis showed that WNVNSW2011 was less virulent than the human-pathogenic American strain of WNV, New York 99 (WNVNY99). To identify viral genes and mutations responsible for the difference in virulence between WNVNSW2011 and WNVNY99 strains, we constructed chimeric viruses with substitution of large genomic regions coding for the structural genes, non-structural genes and untranslated regions, as well as seven individual non-structural gene chimeras, using a modified circular polymerase extension cloning method. Our results showed that the complete non-structural region of WNVNSW2011, when substituted with that of WNVNY99, significantly enhanced viral replication and the ability to suppress type I IFN response in cells, resulting in higher virulence in mice. Analysis of the individual non-structural gene chimeras showed a predominant contribution of WNVNY99 NS3 to increased virus replication and evasion of IFN response in cells, and to virulence in mice. Other WNVNY99 non-structural proteins (NS2A, NS4B and NS5) were shown to contribute to the modulation of IFN response. Thus a combination of non-structural proteins, likely NS2A, NS3, NS4B and NS5, is primarily responsible for the difference in virulence between WNVNSW2011 and WNVNY99 strains, and accumulative mutations within these proteins would likely be required for the Australian WNVNSW2011 strain to become significantly more virulent
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