71 research outputs found

    Multi-field inflation with large scalar fluctuations: non-Gaussianity and perturbativity

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    Recently multi-field inflation models that can produce large scalar fluctuations on small scales have drawn a lot of attention, primarily because they could lead to primordial black hole production and generation of large second-order gravitational waves. In this work, we focus on models where the scalar fields responsible for inflation live on a hyperbolic field space. In this case, geometrical destabilisation and non-geodesic motion are responsible for the peak in the scalar power spectrum. We present new results for scalar non-Gaussianity and discuss its dependence on the model's parameters. On scales around the peak, we typically find that the non-Gaussianity is large and close to local in form. We validate our results by employing two different numerical techniques, utilising the transport approach, based on full cosmological perturbation theory, and the δN formalism, based on the separate universe approximation. We discuss implications of our results for the perturbativity of the underlying theory, focusing in particular on versions of these models with potentially relevant phenomenology at interferometer scales

    Breast imaging and cancer diagnosis during the COVID-19 pandemic: recommendations from the Italian College of Breast Radiologists by SIRM

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    The Italian College of Breast Radiologists by the Italian Society of Medical Radiology (SIRM) provides recommendations for breast care provision and procedural prioritization during COVID-19 pandemic, being aware that medical decisions must be currently taken balancing patient\u2019s individual and community safety: (1) patients having a scheduled or to-be-scheduled appointment for in-depth diagnostic breast imaging or needle biopsy should confirm the appointment or obtain a new one; (2) patients who have suspicious symptoms of breast cancer (in particular: new onset palpable nodule; skin or nipple retraction; orange peel skin; unilateral secretion from the nipple) should request non-deferrable tests at radiology services; (3) asymptomatic women performing annual mammographic follow-up after breast cancer treatment should preferably schedule the appointment within 1\ua0year and 3\ua0months from the previous check, compatibly with the local organizational conditions; (4) asymptomatic women who have not responded to the invitation for screening mammography after the onset of the pandemic or have been informed of the suspension of the screening activity should schedule the check preferably within 3\ua0months from the date of the not performed check, compatibly with local organizational conditions. The Italian College of Breast Radiologists by SIRM recommends precautions to protect both patients and healthcare workers (radiologists, radiographers, nurses, and reception staff) from infection or disease spread on the occasion of breast imaging procedures, particularly mammography, breast ultrasound, breast magnetic resonance imaging, and breast intervention procedures

    Thermoluminescence of zircon: a kinetic model

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    The mineral zircon, ZrSiO4, belongs to a class of promising materials for geochronometry by means of thermoluminescence (TL) dating. The development of a reliable and reproducible method for TL dating with zircon requires detailed knowledge of the processes taking place during exposure to ionizing radiation, long-term storage, annealing at moderate temperatures and heating at a constant rate (TL measurements). To understand these processes one needs a kinetic model of TL. This paper is devoted to the construction of such amodel. The goal is to study the qualitative behaviour of the system and to determine the parameters and processes controlling TL phenomena of zircon. The model considers the following processes: (i) Filling of electron and hole traps at the excitation stage as a function of the dose rate and the dose for both (low dose rate) natural and (high dose rate) laboratory irradiation. (ii) Time dependence of TL fading in samples irradiated under laboratory conditions. (iii) Short time annealing at a given temperature. (iv) Heating of the irradiated sample to simulate TL experiments both after laboratory and natural irradiation. The input parameters of the model, such as the types and concentrations of the TL centres and the energy distributions of the hole and electron traps, were obtained by analysing the experimental data on fading of the TL-emission spectra of samples from different geological locations. Electron paramagnetic resonance (EPR) data were used to establish the nature of the TL centres. Glow curves and 3D TL emission spectra are simulated and compared with the experimental data on time-dependent TL fading. The saturation and annealing behaviour of filled trap concentrations has been considered in the framework of the proposed kinetic model and comparedwith the EPR data associated with the rare-earth ions Tb3+ and Dy3+, which play a crucial role as hole traps and recombination centres. Inaddition, the behaviour of some of the SiOmn− centres has been compared with simulation results.

    Proteomic approach used in the diagnosis of Riedel's thyroiditis: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Riedel's thyroiditis, a rare thyroid disease, can be difficult to diagnose prior to surgical removal and can be confused with malignancy both clinically and cytologically.</p> <p>Case presentation</p> <p>We report the case of a 72-year-old Caucasian woman who presented with a goiter, which showed a rapid increase in size at ultrasound check, suggesting malignancy. Because of inconclusive cytology, a total thyroidectomy was performed. Fine-needle aspiration of the removed thyroid was processed by two-dimensional electrophoresis, and the proteome was compared with both anaplastic cancer and control samples. Significant differentially expressed protein spots were identified by Western blot analysis by using specific antibodies.</p> <p>Conclusions</p> <p>The protein pattern of Riedel's fine-needle aspiration revealed a superimposition with that of the control samples. The comparison of the protein pattern of Riedel's thyroiditis fine-needle aspiration with that of anaplastic cancer showed evidence of a different expression of ferritin heavy chains, ferritin light chains, and haptoglobins, as previously reported in thyroid cancers. Therefore, we performed Western blot analysis of these proteins and validated that their expression levels were low or absent in Riedel's thyroiditis and control samples despite the high concentrations present in fine-needle aspiration anaplastic samples. The concurrent absent or low expression levels of haptoglobin, ferritin light chain, and ferritin heavy chain in Riedel's thyroiditis fine-needle aspiration samples strongly indicate the benign nature of the thyroid lesion. These results suggest the potential applicability of fine-needle aspiration proteome analysis for Riedel's thyroiditis diagnosis.</p

    Meta-analysis of thyroidectomy with ultrasonic dissector versus conventional clamp and tie

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    <p>Abstract</p> <p>Background</p> <p>We conducted a systematic review to evaluate the role of Ultrasonic dissector (UAS) versus conventional clamp and tie in thyroidectomy.</p> <p>Materials and methods</p> <p>We searched for all published RCT in into electronic databases. To be included in the analysis, the studies had to compare thyroidectomy with UAS versus conventional vessel ligation and tight (conventional technique = CT). The following outcomes were used to compare the total thyroidectomy group with UAS versus CT group: operative duration, operative blood loss, overall drainage volume during the first 24 hours, transiet laryngeal nerve palsy, permanent laryngeal nerve palsy, transiet hypocalcaemia and permanent hypocalcaemia.</p> <p>Results</p> <p>There are currently 7 RCT on this issue to compare thyroidectomy with UAS versus CT. From the analysis of these studies it was possible to confront 608 cases: 303 undergoing to thyroidectomy with UAS versus 305 that were treated with CT. Actually, it was shown a relevant advantage of cost-effectiveness in patients treated with UAS; there is a statistically significant reduction of the operative duration (weighted mean difference [WMD], -18.74 minutes; 95% confidence interval [CI], (-26.97 to -10.52 minutes) (P = 0.00001), intraoperative blood loss (WMD, -60.10 mL; 95% CI, -117.04 to 3.16 mL) (P = 0.04) and overall drainage volume (WMD, -35.30 mL; 95% CI, -49.24 to 21.36 mL) (P = 0.00001) in the patients underwent thyroidectomy with UAS. Although the analysis showed that the patients who were treated with USA presented more favourable results in incidence of post-operative complications (transient laryngeal nerve palsy: P = 0.11; permanent laryngeal nerve palsy: not estimable; transient hypocalcaemia: P = 0.24; permanent hypocalcaemia: P = 0.45), these data didn't present statistical relevance.</p> <p>Conclusion</p> <p>This meta-analysis shown a relevant advantage only in terms of cost-effectiveness in patients treated with UAS; it is subsequent to statistically significant reduction of operation duration, intraoperative blood loss and of overall drainage volume during the first 24 hours. Although the analysis showed that the patients who were treated with UAS presented more favourable results in incidence of post-operative complications (transiet laryngeal nerve palsy; transiet hypocalcaemia and permanent hypocalcaemia), these data didn't present statistical relevance.</p

    Neoadjuvant chemotherapy in breast cancer-response evaluation and prediction of response to treatment using dynamic contrast-enhanced and diffusion-weighted MR imaging

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    Objective To explore the predictive value of MRI parameters and tumour characteristics before neoadjuvant chemotherapy (NAC) and to compare changes in tumour size and tumour apparent diffusion coefficient (ADC) during treatment, between patients who achieved pathological complete response (pCR) and those who did not. Methods Approval by the Regional Ethics Committee and written informed consent were obtained. Thirty-one patients with invasive breast carcinoma scheduled for NAC were enrolled (mean age, 50.7; range, 37–72). Study design included MRI before treatment (Tp0), after four cycles of NAC (Tp1) and before surgery (Tp2). Data in pCR versus non-pCR groups were compared and cut-off values for pCR prediction were evaluated. Results Before NAC, HER2 overexpression was the single significant predictor of pCR (p=0.006). At Tp1 ADC, tumour size and changes in tumour size were all significantly different in the pCR and non-pCR groups. Using 1.42×10−3 mm2/s as the cut-off value for ADC, pCR was predicted with sensitivity and specificity of 88% and 80%, respectively. Using a cut-off value of 83% for tumour volume reduction, sensitivity and specificity for pCR were 91% and 80%. Conclusion ADC, tumour size and tumour size reduction at Tp1 were strong independent predictors of pCR

    Apoptosis control and proliferation marker in human normal and neoplastic adrenocortical tissues

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    We evaluated by immunohistochemistry the expression of the Bcl-2 and p53 proteins, as markers of apoptosis control, and of MIB-1, as a marker of cell proliferation, in a series of normal and neoplastic adrenocortical tissues. The specimens were 13 normal adrenals, 13 aldosterone-producing adenomas, 13 non-functioning adenomas and 16 carcinomas. Results were calculated as percentage of immunostained cells by using specific antibodies. No p53 protein was detected in any of the adrenocortical adenomas (functioning and non functioning) or normal adrenals, while p53 was overexpressed in 15 out of 16 carcinomas. In particular, 10 adrenal cancer specimens (62.5%) showed strong staining in a high percentage (range 10–50%) of the malignant cells. The percentage of Bcl-2 positive cells was higher (P<0.05 or less) in non-functioning adenomas (8.1±1.9%) and in carcinomas (14.9±5.6%) than in normals (2.9±0.9%) and aldosterone-producing adenomas (5.3±1.3%) since four specimens of the non-functioning adenomas-group (30.7%) and six of the carcinomas-group (37.5%) showed over 10% positivity (cut-off for normal values, set at 90th percentile of our controls). MIB-1 positivity was 0.50±0.36% in normals, 0.54±0.08% in non-functioning adenomas and 0.54±0.08% in aldosterone-producing adenomas. MIB-1 was expressed in all carcinomas with values (13.7±3.1%) significantly (P<0.0006) higher than in the other groups. In conclusion, the present data indicate that the apoptosis control and proliferation activity evaluated by the p53 and MIB-1 proteins are impaired in adrenal carcinomas but preserved in adenomas, independently of their functional status. Therefore, these immunohistochemical markers, overexpressed in carcinomas only, may be useful in the diagnosis of malignancy in adrenocortical tumours. Whether Bcl-2 positivity found in some carcinomas and non-functioning adenomas may constitute, in the latter, a negative prognostic marker is still unknown

    Cosmology with the Laser Interferometer Space Antenna

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    The Laser Interferometer Space Antenna (LISA) has two scientific objectives of cosmological focus: to probe the expansion rate of the universe, and to understand stochastic gravitational-wave backgrounds and their implications for early universe and particle physics, from the MeV to the Planck scale. However, the range of potential cosmological applications of gravitational wave observations extends well beyond these two objectives. This publication presents a summary of the state of the art in LISA cosmology, theory and methods, and identifies new opportunities to use gravitational wave observations by LISA to probe the universe
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