6,237 research outputs found
Inferring the high velocity of landslides in Valles Marineris on Mars from morphological analysis
The flow characteristics and velocities of three landslides in Valles Marineris on Mars are investigated using detailed morphological analyses of high-resolution images and dynamical calculations based on the run-up and curvature of the landslide deposits. The morphologies of the landslides are described, especially concerning those characteristics that can provide information on the dynamics and velocity. The long runout and estimated high velocities, often exceeding 100 m/s, confirm a low basal friction experienced by these landslides. Because subaqueous landslides on Earth exhibit reduced friction, we explore the scenario of sub-lacustrine failures, but find little support to this hypothesis. The environmental conditions that better explain the low friction and the presence of longitudinal furrows suggest an aerial environment with a basal soft and naturally lubricating medium on which friction diminished gradually; in this perspective, ice is the most promising candidate
Congenital rhabdomyosarcoma: a different clinical presentation in two cases
Background: Rhabdomyosarcoma (RMS), one of the most common soft tissue sarcomas of childhood, is very rare in the neonatal period (0.4-2% of cases). In order to gain a deeper understanding of this disease at such age, patient and tumor features, as well as treatment modality and outcome need to be reported. Case presentation: We describe two cases with congenital RMS treated at Bambino Gesù Children's Hospital between 2000 and 2016. They represent only 2.24% of all RMS patients diagnosed during that period in our Institution; this data is in agreement with the incidence reported in the literature. They reflect the two different clinical forms in which the disease may manifest itself. One patient, with the alveolar subtype (positive for specific PAX3-FOXO1 fusion transcript) and disseminated disease, had a fatal outcome with central nervous system (CNS) progression despite conventional and high dose chemotherapy. The other child, with the localized embryonal subtype, was treated successfully with conservative surgery and conventional chemotherapy, including prolonged maintenance therapy. He is disease free at 7 years of follow-up. Conclusions: RMS can also be diagnosed during the neonatal period. Given the young age, disease management is often challenging, and especially for the alveolar subtype, the outcome is dismal despite intensified multimodality therapy. In fact, it characteristically manifests with multiple subcutaneous nodules and progression most commonly occurs in the CNS (Rodriguez-Galindo et al., Cancer 92(6):1613-20, 2001). In this context, CNS prophylaxis could play a role in preventing leptomeningeal dissemination, and molecular studies can allow a deeper tumor characterization, treatment stratification and identification of new potential therapeutic targets
Stars caught in the braking stage in young Magellanic Clouds clusters
The color-magnitude diagrams of many Magellanic Cloud clusters (with ages up
to 2 billion years) display extended turnoff regions where the stars leave the
main sequence, suggesting the presence of multiple stellar populations with
ages which may differ even by hundreds million years (Mackey et al. 2008,
Milone et al. 2009, Girardi et al. 2011). A strongly debated question is
whether such an extended turnoff is instead due to populations with different
stellar rotations (Girardi et al. 2011, Goudfrooij et al. 2011, Rubele et al.
2013, Li et al. 2014). The recent discovery of a `split' main sequence in some
younger clusters (about 80--400Myr) added another piece to this puzzle. The
blue (red) side of the main sequence is consistent with slowly (rapidly)
rotating stellar models (D'Antona et al. 2015, Milone et al. 2016, Correnti et
al. 2017, Milone et al 2016), but a complete theoretical characterization of
the observed color-magnitude diagram appeared to require also an age spread
(Correnti et al. 2017). We show here that, in three clusters so far analyzed,
if the blue main sequence stars are interpreted with models that have been
always slowly rotating, they must be about 30% younger than the rest of the
cluster. If they are instead interpreted as stars initially rapidly rotating,
but that have later slowed down, the age difference disappears, and "braking"
also helps to explain the apparent age differences of the extended turnoff. The
age spreads in Magellanic Cloud clusters are a manifestation of rotational
stellar evolution. Observational tests are suggested.Comment: Accepted for publication and in state of Advance Online Publication
(from 24 July 2017) on Nature Astronom
Chromogranin A: From Laboratory to Clinical Aspects of Patients with Neuroendocrine Tumors
Background. Neuroendocrine tumors (NETs) are characterized by having behavior and prognosis that depend upon tumor histology, primary site, staging, and proliferative index. The symptoms associated with carcinoid syndrome and vasoactive intestinal peptide tumors are treated with octreotide acetate. The PROMID trial assesses the effect of octreotide LAR on the tumor growth in patients with well-differentiated metastatic midgut NETs. The CLARINET trial evaluates the effects of lanreotide in patients with nonfunctional, well-, or moderately differentiated metastatic enteropancreatic NETs. Everolimus has been approved for the treatment of advanced pancreatic NETs (pNETs) based on positive PFS effects, obtained in the treated group. Sunitinib is approved for the treatment of patients with progressive gastrointestinal stromal tumor or intolerance to imatinib, because a randomized study demonstrated that it improves PFS and overall survival in patients with advanced well-differentiated pNETs. In a phase II trial, pasireotide shows efficacy and tolerability in the treatment of patients with advanced NETs, whose symptoms of carcinoid syndrome were resistant to octreotide LAR. An open-label, phase II trial assesses the clinical activity of long-acting repeatable pasireotide in treatment-naive patients with metastatic grade 1 or 2 NETs. Even if the growth of the neoplasm was significantly inhibited, it is still unclear whether its antiproliferative action is greater than that of octreotide and lanreotide. Because new therapeutic options are needed to counter the natural behavior of neuroendocrine tumors, it would also be useful to have a biochemical marker that can be addressed better in the management of these patients. Chromogranin A is currently the most useful biomarker to establish diagnosis and has some utility in predicting disease recurrence, outcome, and efficacy of therapy
Self-enrichment in Globular Clusters: the extreme He-rich population of NGC 2808
Almost several decades after the discovery of the first multiple populations
in galactic globular clusters (GC) the debate on their formation is still
extremely current and NGC2808 remains one of the best benchmark to test any
scenario for their origin and the evolution. In this work we focus on the
chemical composition of stars belonging to the extreme He-rich population
populated by stars with the most extreme abundance of Mg, Al, Na, O and Si. We
checked whether the most recent measures are consistent with the AGB yields of
stars of . These stars evolve on time scales of the order of
40-60 Myr and eject matter strongly enriched in helium, owing to a deep
penetration of the surface convective zone down to regions touched by CNO
nucleosynthesis occurring after the core He-burning phase. Since the big
unknown of the AGB phase of massive stars is the mass loss, we propose a new
approch that takes into account the effects of the radiation pressure on dust
particles. We show that this more realistic description is able to reproduce
the observed abundances of Mg, Al, Na and Si in these extreme stars. The large
spread in the oxygen abundances is explained by invoking deep mixing during the
RGB phase. It will be possible to check this work hypothesis as soon as the
oxygen measurements of the main sequence stars of NGC2808 will be available.Comment: 12 pages, 5 figures, accepted 2018 June 29 by MNRA
Predictive Role of CD36 Expression in HER2-Positive Breast Cancer Patients Receiving Neoadjuvant Trastuzumab
CD36 expression; Breast cancer; Neoadjuvant trastuzumabExpresión CD36; Cáncer de mama; Trastuzumab neoadyuvanteExpressió CD36; Càncer de mama; Trastuzumab neoadjuvantBackground
Despite huge efforts to identify biomarkers associated with long-term clinical outcomes in patients with early-stage HER2-positive breast cancer (HER2+ BC) treated with (neo)adjuvant anti-HER2 therapy, no reliable predictors have been identified so far. Fatty acid uptake, a process mediated by the transmembrane transporter CD36, has recently emerged as a potential determinant of resistance to anti-HER2 treatments in preclinical HER2+ BC models.
Methods
Here, we investigated the association between baseline intratumor CD36 gene expression and event-free survival in 180 patients enrolled in the phase III trial Neoadjuvant Lapatinib and/or Trastuzumab Treatment Optimization (NeoALTTO), which randomly assigned stage II-III HER2+ BC patients to receive neoadjuvant lapatinib, trastuzumab, or lapatinib-trastuzumab in combination with chemotherapy. To this aim, we selected NeoALTTO trial patients for whom pretreatment whole transcriptomic data were available. The main study results were validated in an independent cohort of patients enrolled in the neoadjuvant phase II trial NeoSphere.
Results
In 180 NeoALTTO patients, high intratumor CD36 expression was independently associated with worse event-free survival in patients treated with trastuzumab-based therapy (hazard ratio [HR] = 1.72, 95% confidence interval [CI] = 1.20 to 2.46), but not with lapatinib-based (HR = 1.02, 95% CI = 0.68 to 1.53) or trastuzumab-lapatinib–based (HR = 1.08, 95% CI = 0.60 to 1.94) therapy. Among 331 NeoSphere patients evaluated, high CD36 expression was independently associated with worse patient disease-free survival in both the whole study cohort (HR = 1.197, 95% CI = 1.002 to 1.428) and patients receiving trastuzumab-based neoadjuvant therapy (HR = 1.282, 95% CI = 1.049 to 1.568).
Conclusions
High CD36 expression predicts worse clinical outcomes in early-stage HER2+ BC treated with trastuzumab-based neoadjuvant therapy.The NeoALTTO trial was sponsored by GlaxoSmithKline; the NeoSphere trial was sponsored by F. Hoffmann-La Roche. Our subanalysis of the NeoALTTO and NeoSphere trials received no funding by pharmaceutical companies
Role of Small farming in food security and sustainability: a case study for Tuscany (IT)
The debate on the size of farming, and its relevance for policy purposes, has come back to the fore in recent years. The “International Year of Family Farming and Smallholder Farming”, held by FAO in 2014, aimed to raise the profile of family and smallholder farming worldwide”. During EXPO 2015, a debate followed on structural developments in agriculture and the implications for the competitiveness and sustainability of the agri-food sector and rural areas. Despite a declining number of agricultural holdings and a gradual increase in average farm size, the agricultural sector is largely composed by farms with less than 5 ha of agricultural land and a standard output below 4 000 euro per year. Beyond economic size and value of production, other criteria (e.g. labour units and family involvement can be adopted), alone or in combination, to define size of farming. Academic literature provides a mixed picture on weather a declining number of farms, and a gradual increase in size should be welcomed or contrasted. Oppositional arguments contrasting smaller and larger farm structures with respect to sustainability and food and nutrition security, are nourished by the lack of sufficient or unambiguous scientific evidence. A first line of thought stresses the distinctiveness of smaller farms in delivering food security and sustainability (Rabinowicz, 2014) and the capacity of small farms to mobilize resources additional to those procured
through market exchange (van der Ploeg, 2013). A second line of thought considers size as a nonrelevant criterion to assess the performance on food security and sustainability (OECD, 2005), supporting the view on steering behaviours oriented towards improved sustainability, regardless of size. Dualistic debates often focus on some aspects of sustainability and neglect others (Kirwan et al. 2017) or overlook the importance of complementarity between complex agro-food systems and territoriality, as local context largely affects what structural change is desirable at
territorial level (Darnhofer et al. 2010). This contribution presents the conceptual and analytical framework adopted in a research project named
SALSA, “Small farms, small food businesses and sustainable food and nutrition security (FNS)”, and provides an illustration on one of the 35 reference regions selected. The analysis considers Lucca province in Tuscany and aims at generating preliminary insights in relation to the role of small farms in food and nutrition security
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