622 research outputs found

    The onset and solidification path of a basaltic melt by in situ differential scanning calorimetry (DSC) and ex situ investigations

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    The in situ differential scanning calorimetry (DSC) technique has been applied to investigate the solidification paths of a basaltic liquid. The starting glass was heated up to 1300◦C, kept at this superliquidus temperature for 2 h and cooled at rates (∆T/∆t) of 7, 60, 180, 1000, and 1800◦C/h, down to 800 and 600◦C. Glass transition temperature (Tg), crystallization temperature (Tx_HR) and melting temperature (Tm) were measured by in situ DSC spectra on heating. Tx measured along the cooling paths (Tx_CR) shows exothermic peaks that change from a single symmetric shape (7 and 60◦C/h) to multi-component patterns (180, 1000, and 1800◦C/h). The recovered products characterized by field emission gun source of the scanning electron microscopy and electron probe micro-analyzer-wavelength dispersive spectrometers show a phase assemblage of spinel (sp), clinopyroxene (cpx), melilite (mel), plagioclase (plg), and glass. Moreover, crystal size distributions (CSDs) and growth rates (Gmax and GCSD) were also determined. The crystal content slightly increases from 7 to 1800◦C/h. Faceted sp are present in all the run products with an amount always <2 area%. Cpx increases from 7 to 1800◦C/h, changing its texture from almost faceted to dendritic between 60 and 180◦C/h. The area% of mel follows an asymmetric Gaussian trend, while plg nucleates only at 7◦C/h with a content <2 area%. The coupling of DSC and SEM outcomes indicate that sp nucleate first, followed by cpx and mel (and/or plg). The increment of ∆T/∆t causes an increase of the CSD slope (m) and crystal population density per size (n0 ), as well as a decrease of the crystal size, for both cpx and sp. The log-linear CSD segments with different slopes at 7 and 60◦C/h suggest multiple nucleation events and crystal growth by coarsening. Gmax and GCSD for cpx and sp directly measured on the actual crystallization time by DSC spectra, both increase with the increasing of ∆T/∆t. The onset temperature of crystallization (Txi ) decreases as ∆T/∆t increases, following an exponential trend that defines the uppermost portion of a time-transformation-temperature-like curve. This analytical model allows us to quantitatively model the kinetic crystallization paths of dry basalts

    Volume Flow Rate Estimation for Small Explosions at Mt. Etna, Italy, From Acoustic Waveform Inversion

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    Rapid assessment of the volume and the rate at which gas and pyroclasts are injected into the atmosphere during volcanic explosions is key to effective eruption hazard mitigation. Here, we use data from a dense infrasound network deployed in 2017 on Mt. Etna, Italy, to estimate eruptive volume flow rates (VFRs) during small gas-and-ash explosions.We use a finite-difference time-domain approximation to compute the acoustic Green's functions and perform a full waveform inversion for a multipole source, combining monopole and horizontal dipole terms. The inversion produces realistic estimates of VFR, on the order of 4 × 104 m3/s and well-defined patterns of source directivity. This is the first application of acoustic waveform inversion at Mt. Etna. Our results demonstrate that acoustic waveform inversion is a mature and robust tool for assessment of source parameters and holds potential as a tool to provide rapid estimates of VFR in near real time.This study was supported by NERC Grant NE/P00105X/1 and by European Unions Horizon 2020 Research and Innovation Programme Under the Marie Sklodowska-Curie Grant Agreement 798480

    Prognostic Relevance of Neutrophil to Lymphocyte Ratio (NLR) in Luminal Breast Cancer: A Retrospective Analysis in the Neoadjuvant Setting

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    The neutrophil to lymphocyte ratio (NLR) is a promising predictive and prognostic factor in breast cancer. We investigated its ability to predict disease-free survival (DFS) and overall survival (OS) in patients with luminal A- or luminal B-HER2-negative breast cancer who received neoadjuvant chemotherapy (NACT). Pre-treatment complete blood cell counts from 168 consecutive patients with luminal breast cancer were evaluated to assess NLR. The study population was stratified into NLRlow or NLRhigh according to a cut-off value established by receiving operator curve (ROC) analysis. Data on additional pre- and post-treatment clinical-pathological characteristics were also collected. Kaplan-Meier curves, log-rank tests, and Cox proportional hazards models were used for statistical analyses. Patients with pre-treatment NLRlow showed a significantly shorter DFS (HR: 6.97, 95% CI: 1.65-10.55, p = 0.002) and OS (HR: 7.79, 95% CI: 1.25-15.07, p = 0.021) compared to those with NLRhigh. Non-ductal histology, luminal B subtype, and post-treatment Ki67 ≥ 14% were also associated with worse DFS (p = 0.016, p = 0.002, and p = 0.001, respectively). In a multivariate analysis, luminal B subtype, post-treatment Ki67 ≥ 14%, and NLRlow remained independent prognostic factors for DFS, while only post-treatment Ki67 ≥ 14% and NLRlow affected OS. The present study provides evidence that pre-treatment NLRlow helps identify women at higher risk of recurrence and death among patients affected by luminal breast cancer treated with NACT

    Timely DNA Vaccine Combined with Systemic IL-12 Prevents Parotid Carcinomas before a Dominant-Negative p53 Makes Their Growth Independent of HER-2/neu Expression

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    Double transgenic mice overespressing the transforming rat HER-2/neu oncogene and the mutated p53, with both deminant-negative and a gain-of-function properties, display early aggressive and metastasizing parotid tumors. Multiple acinar and ductal hyperplasia foci overexpressing the HER-2/neu gene product are evident at wk 5 and progress to poorly differentiated carcinoma by wk 7. Mice die before wk 18 with invasive carcinomas and multiple metastases that no longer express HER-2/neu. A combination of repeated electroporations of plasmids coding for the extracellular and transmembrane domains of the rat HER-2/neu receptor with systemic IL-12 administrations started when the parotids that present diffuse hyperplasia protected all female and 50% of the male mice until the close of the experiment at wk 40. This combined treatment began when multifocal in situ - carcinomas that were already present cured 33% of the females and 25 % of the males. The most prominent immunologic features associated with the antitumor protection were the production of high titers of anti-HER-2/neu Abs and the nonappearance of cell-mediated cytotoxic reactivity. In conclusion, anti-HER-2/neu vaccination combined with systemic IL-12 control parotid carcinomas as far as p53 mutation makes their growth independent of HER-2/neu expression

    Teacher confidence in professional training: The predictive roles of engagement and burnout

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    Teachers' work engagement positively impacts teachers' attitudes towards their job. Nevertheless, teachers may experience burnout during their career, which negatively impacts their professional learning opportunities. In this study we investigated the relationship between teachers' levels of burnout, work engagement, and their confidence in in-service training in a sample of Italian teachers. We expected that burnout mediated the relationship between work engagement and teachers' confidence in training. A total of 481 teachers completed self-report questionnaires about engagement and burnout, with an ad hoc Confidence in Training Index developed to assess their attitudes towards professional development courses. The mediation analysis confirmed that the teachers' levels of burnout mediated the relationship between their work engagement and their confidence in in-service training. Findings suggest that teacher confidence in policies about professional training should be evaluated by taking into account their level of engagement and burnout

    Interleukin-15 is required for immunosurveillance and immunoprevention of HER2/neu-driven mammary carcinogenesis

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    We previously demonstrated that HER2/neu-driven mammary carcinogenesis can be prevented by an interleukin-12 (IL-12)-adjuvanted allogeneic HER2/neu-expressing cell vaccine. Since IL-12 can induce the release of interleukin-15 (IL-15), in the present study we investigated the role played by IL-15 in HER2/neu driven mammary carcinogenesis and in its immunoprevention
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