36 research outputs found

    Are hierarchically formed embedded star clusters surviving gas expulsion depending on their initial conditions?

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    We investigate the dissolution process of young embedded star clusters with different primordial mass segregation levels using fractal distributions by means of N-body simulations. We combine several star clusters in virial and subvirial global states with Plummer and uniform density profiles to mimic the gas. The star clusters have masses of M-stars = 500 M-circle dot that follow an initial mass function where the stars have maximum distance from the centre of r = 1.5 pc. The clusters are placed in clouds that at the same radius have masses of M-cloud = 2000 M-circle dot, resulting in star formation efficiency of 0.2. We remove the background potential instantaneously at a very early phase, mimicking the most destructive scenario of gas expulsion. The evolution of the fraction of bound stellar mass is followed for a total of 16 Myr for simulations with stellar evolution and without. We compare our results with previous works using equal-mass particles where an analytical physical model was used to estimate the bound mass fraction after gas expulsion. We find that independent of the initial condition, the fraction of bound stellar mass can be well predicted just right after the gas expulsion but tends to be lower at later stages, as these systems evolve due to the stronger two-body interactions resulting from the inclusion of a realistic initial mass function. This discrepancy is independent of the primordial mass segregation level

    Fenotipos de disfunción crónica del injerto pulmonar

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    En la actualidad el rechazo crónico en el trasplante pulmonar incluye diferentes formas de presentación clínica englobadas bajo el término “disfunción crónica de injerto”, por sus siglas en inglés (CLAD, Chronic lung allograft dysfunction). Se han diferenciado dos fenotipos de CLAD, expresión de rechazo crónico, con presentación clínicoimagenológica, anatomo-patológica y evolutiva diferente. La disfunción crónica del injerto pulmonar con fenotipo obstructivo, correspondiente a la bronquiolitis obliterante (BO) / síndrome de bronquiolitis obliterante (SBO), y la de fenotipo restrictivo correspondiente al síndrome restrictivo del injerto (RAS, restrictive allograft syndrome)1 . Se presentan dos casos clínicos de trasplante bipulmonar con disfunción crónica del injerto pulmonar que ejemplifican los fenotipos de rechazo crónico bajo las formas de SBO y RAS, respectivamente. Ambos pacientes recibieron un retrasplante pulmonar. La anatomía patológica de los pulmones explantados confirmó el diagnóstico en ambos casos.Fil: Curbelo, Pablo. Hospital Maciel; UruguayFil: Cáneva, Jorge. Fundación Favaloro; ArgentinaFil: Chao, Cecilia. Hospital Maciel; UruguayFil: Osses, Juan M.. Fundación Favaloro; ArgentinaFil: Vigliano, Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Medicina Traslacional, Trasplante y Bioingeniería. Fundación Favaloro. Instituto de Medicina Traslacional, Trasplante y Bioingeniería; ArgentinaFil: Tommasino, Nicolás. Hospital Maciel; UruguayFil: Bertolotti, Alejandro Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Medicina Traslacional, Trasplante y Bioingeniería. Fundación Favaloro. Instituto de Medicina Traslacional, Trasplante y Bioingeniería; ArgentinaFil: Musetti, Ana. Hospital de Clínicas; Urugua

    The SOFIA Massive (SOMA) Star Formation Survey. IV. Isolated Protostars

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    We present similar to 10-40 mu m SOFIA-FORCAST images of 11 isolated protostars as part of the SOFIA Massive (SOMA) Star Formation Survey, with this morphological classification based on 37 mu m imaging. We develop an automated method to define source aperture size using the gradient of its background-subtracted enclosed flux and apply this to build spectral energy distributions (SEDs). We fit the SEDs with radiative transfer models, developed within the framework of turbulent core accretion (TCA) theory, to estimate key protostellar properties. Here, we release the sedcreator python package that carries out these methods. The SEDs are generally well fitted by the TCA models, from which we infer initial core masses M ( c ) ranging from 20-430 M (circle dot), clump mass surface densities sigma(cl) similar to 0.3-1.7 g cm(-2), and current protostellar masses m (*) similar to 3-50 M (circle dot). From a uniform analysis of the 40 sources in the full SOMA survey to date, we find that massive protostars form across a wide range of clump mass surface density environments, placing constraints on theories that predict a minimum threshold sigma(cl) for massive star formation. However, the upper end of the m (*)-sigma(cl) distribution follows trends predicted by models of internal protostellar feedback that find greater star formation efficiency in higher sigma(cl) conditions. We also investigate protostellar far-IR variability by comparison with IRAS data, finding no significant variation over an similar to 40 yr baseline

    Lung Retransplantation with Positive Crossmatch in Primary Lung Transplantation Complicated by Antibody-Mediated Rejection

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    La hipertensión arterial pulmonar (HAP) representa el 2,6% de los trasplantes pulmonares (TP), con una mediana de supervivencia condicional(desde los 30 días del TP) de 9,8 años. Son frecuentes, el rechazo celular agudo (ACR) y la disfunción crónica del injerto (CLAD),mientras que es infrecuente el rechazo mediado por anticuerpos (AMR). El retrasplante pulmonar (RTP) constituye el 4% del TP mundial,debido a complicaciones en la vía aérea, disfunción primaria del injerto, ACR y CLAD. Mujer de 22 años, portadora de HAP idiopática(HAPI) desde el año 2013, trasplantada bipulmonar (TBP) en enero de 2018. A los 16 meses presentó neumonía adquirida en la comunidad.En una internación posterior, presentó ACR y a pesar de pulsos de metilprednisolona, progresó a requerimientos de cánula de altoflujo y ventilación mecánica no invasiva hospitalaria, caída del VEF1, y tomografía de tórax con vidrio esmerilado difuso y engrosamientoirregular reticular del intersticio subpleural; interpretándose como CLAD a predominio de síndrome de bronquiolitis obliterante (BOS),con presencia de anticuerpos específicos contra el donante (DSA). En enero de 2020 se realizó nuevo TP y ante cross-match positivo, serealizó plasmaféresis y reposición de IgG. Al mes del egreso, no se observaron signos de rechazo en control de biopsias transbronquiales.Entre 2 y 10% de los pacientes con indicación primaria de TP por HAPI son sometidos a retrasplante pulmonar (RTP). La presencia deDSA y el miss-match de HLA, no son contraindicaciones para el RTP.Pulmonary arterial hypertension (PAH) represents 2.6% of lung transplantations (LT), with a conditional median survival (from 30 days after LT) of 9.8 years. Acute cellular rejection (ACR) and chronic lung allograft dysfunction (CLAD) are common; whereas the antibody-mediated rejection (AMR) is not. Lung retransplantation (LR) accounts for 4% of global LTs for complications in the airways, primary allograft dysfunction, ACR and CLAD. 22-year-old woman with idiopathic PAH (IPAH) since 2013, who underwent a double-lung transplantation (DLT) in January 2018. 16 months after transplantation she presented community-acquired pneumonia. During a subsequent hospitalization, she presented ACR. Despite the fact that she received pulse methylprednisolone, she required high-flow cannula therapy and hospital non-invasive mechanical ventilation; the FEV1 was reduced and she underwent a chest tomography with diffuse ground glass opacities and irregular reticular thickening of the subpleural interstitium; interpreting the predominance of BOS (bronchiolitis obliterans syndrome) as CLAD, with presence of donor-specific antibodies (DSA). In January 2020, she received a new DLT and due to a positive crossmatch, she was treated with plasmapheresis and IgG replacement. One month after hospital discharge, no signs of rejection were observed at the BTB (bone-patellar tendon-bone) control. Between 2 to 10% of patients with primary indication of LT for IPAH are subjected to lung retransplantation (LR). The presence of DSA and HLA (human leucocyte antigen) mismatch aren’t contraindications to LR.Fil: Calderón Soriano, Juan C.. Fundación Favaloro; ArgentinaFil: Nazzo, María V.,. Fundación Favaloro; ArgentinaFil: Pérez Páez, Martha I.. Fundación Favaloro; ArgentinaFil: Virhuez, Yblin. Fundación Favaloro; ArgentinaFil: Balcazar, Jonathan. Fundación Favaloro; ArgentinaFil: Vicente, Luis. Fundación Favaloro; ArgentinaFil: Ahumada, Rosalía. Fundación Favaloro; ArgentinaFil: Osses, Juan M.. Fundación Favaloro; ArgentinaFil: Vigliano, Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Medicina Traslacional, Trasplante y Bioingeniería. Fundación Favaloro. Instituto de Medicina Traslacional, Trasplante y Bioingeniería; ArgentinaFil: Bertolotti, Alejandro Mario. Fundación Favaloro; ArgentinaFil: Caneva, Jorge O.. Fundación Favaloro; Argentin

    Large expert-curated database for benchmarking document similarity detection in biomedical literature search

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    Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Release of norepinephrine from human ovary

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    We investigated the possibility that norepinephrine from the human ovary is released after nerve stimulation and that this neurotransmitter is coupled to a steroidogenic response. Biologically significant levels of both norepinephrine and dopamine were found in human ovarian biopsies. [3H]norepinephrine incorporated in vitro was readily released by electrical stimulation in a Ca2+-dependent process. Ovarian membrane preparations exhibited specific binding sites for the β-adrenergic antagonist [3H]dihydroalprenolol. Displacement of [3H]dihydroalprenolol with zinterol (a specific β2-agonist) indicated that 72% of these sites were type β2-receptors. β-receptors were also present on granulosa cells. Stimulation of granulosa cells with luteinizing hormone or the β-agonist isoproterenol increased the release of progesterone after 4 d in culture. These results suggest that the sympathetic nerves present in human ovary are coupled to β-adrenergic receptors present in endocrine cells and, as i

    Effects of Fatty Acids on Intracellular [Ca2+], Mitochondrial Uncoupling and Apoptosis in Rat Pachytene Spermatocytes and Round Spermatids.

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    The aim of this work was to explore the ability of free arachidonic acid, palmitic acid and the unsaturated fatty acids oleic acid and docosahexaenoic acid to modify calcium homeostasis and mitochondrial function in rat pachytene spermatocytes and round spermatids. In contrast to palmitic acid, unsaturated fatty acids produced significant increases in intracellular calcium concentrations ([Ca2+]i) in both cell types. Increases were fatty acid specific, dose-dependent and different for each cell type. The arachidonic acid effects on [Ca2+]i were higher in spermatids than in spermatocytes and persisted when residual extracellular Ca2+ was chelated by EGTA, indicating that the increase in [Ca2+]i originated from release of intracellular calcium stores. At the concentrations required for these increases, unsaturated fatty acids produced no significant changes in the plasma membrane potential of or non-specific permeability in spermatogenic cells. For the case of arachidonic acid, the [Ca2+]i increases were not caused by its metabolic conversion to eicosanoids or anandamide; thus we attribute this effect to the fatty acid itself. As estimated with fluorescent probes, unsaturated fatty acids did not affect the intracellular pH but were able to induce a progressive decrease in the mitochondrial membrane potential. The association of this decrease with reduced reactive oxygen species (ROS) production strongly suggests that unsaturated fatty acids induced mitochondrial uncoupling. This effect was stronger in spermatids than in spermatocytes. As a late event, arachidonic acid induced caspase 3 activation in a dose-dependent manner both in the absence and presence of external Ca2+. The concurrent but differential effects of unsaturated fatty acids on [Ca2+]i and mitochondrial functions are additional manifestations of the metabolic changes that germ cells undergo during their differentiation
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