934 research outputs found

    Coherent generation of symmetry-forbidden phonons by light-induced electron-phonon interactions in magnetite

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    Symmetry breaking across phase transitions often causes changes in selection rules and emergence of optical modes which can be detected via spectroscopic techniques or generated coherently in pump-probe experiments. In second-order or weakly first-order transitions, fluctuations of the order parameter are present above the ordering temperature, giving rise to intriguing precursor phenomena, such as critical opalescence. Here, we demonstrate that in magnetite (Fe3_3O4_4) light excitation couples to the critical fluctuations of the charge order and coherently generates structural modes of the ordered phase above the critical temperature of the Verwey transition. Our findings are obtained by detecting coherent oscillations of the optical constants through ultrafast broadband spectroscopy and analyzing their dependence on temperature. To unveil the coupling between the structural modes and the electronic excitations, at the origin of the Verwey transition, we combine our results from pump-probe experiments with spontaneous Raman scattering data and theoretical calculations of both the phonon dispersion curves and the optical constants. Our methodology represents an effective tool to study the real-time dynamics of critical fluctuations across phase transitions

    Immunohistochemical evaluation of bone metastases

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      Introduction. Metastases are the most common type of malignancy involving the bone, while bone is the third most frequent site for metastases, after the lung and liver. In some patients, medical history, physical and laboratory exami­nation are not conclusive to identify the primary tumor site. In such cases a bone biopsy and immunohistochemical analysis may contribute to the diagnosis, determination of appropriate treatment and evaluation of prognosis. In this study, we tried to evaluate the imunochistochemical expression in bone metastases. Material and methods. We reviewed 125 patients, with a mean age of 63 years, treated for bone metastases in our institution. All patients received palliative orthopaedic surgery for bone metastatic carcinoma. Fifty-eight patients had already an established diagnosis of the primary tumor, while 67 patients presented metastases with an unknown primary tumor origin. Immunohistochemical analysis was performed to intra-operative bone biopsy specimens. The expression of cytokeratine 7, cytokeratin 20 and the expression of a panel of other organ-specific markers were re­corded. In patients with a known primary tumor, we examined the relationship between the origin of metastases, as suggested by the cytokeratin phenotype, compared with the one indicated by the initial histological diagnosis. We also recorded the efficacy of organ-specific markers to identify the primary tumor origin in epithelial bone metastases and we evaluated the prognosis between patients with a immunohistologically determined primary tumor origin, with those with an undetermined one. Results. Associations of cytokeratine 7 and cytokeratine 20 expression confirmed diagnosis in 51 out of the 58 patients (88%) with a known primary tumor (Cohen’s K test 0.79 SE 0.80, P < 0.0005). Immunohistochemical analysis also contributed to establish the diagnosis of patients with an unknown primary tumor, yielding diagnosis in 35 out of the 67 cases (52%). Patients with an immunochistologically undetermined primary tumor site presented a statisti­cally significant poorer prognosis. Conclusions. Cytokeratine 7 and cytokeratine20 are useful immunochistochemical markers in determining a pre­liminary evaluation of bone metastases. Organ-specific immunohistochemical markers have a reliable role in either suggesting or confirming the possible origin of metastases. An indeterminate immunohistochemical phenotype seems to relate to a less differentiated lesion, with a worse prognosis

    Immunohistochemical evaluation of bone metastases

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      Introduction. Metastases are the most common type of malignancy involving the bone, while bone is the third most frequent site for metastases, after the lung and liver. In some patients, previous medical history, physical and laboratory examination are not conclusive to identify the primary tumor site. In such cases a bone biopsy and im­munohistochemical analysis may contribute to the diagnosis, determination of appropriate treatment and evaluation of prognosis. In this study, we tried to evaluate the imunochistochemical expression in bone metastases. Material and methods. We reviewed 125 patients, with a mean age of 63 years, treated for bone metastases in our institution. All patients received palliative orthopaedic surgery for bone metastatic carcinoma. Fifty-eight patients had already an established diagnosis of the primary tumor, while 67 patients presented metastases with an unknown primary tumor origin. Immunohistochemical analysis was performed to intra-operative bone biopsy specimens. The expression of cytokeratine 7, cytokeratin 20 and the expression of a panel of other organ-specific markers were re­corded. In patients with a known primary tumor, we examined the relationship between the origin of metastases, as suggested by the cytokeratin phenotype, compared with the one indicated by the initial histological diagnosis. We also recorded the efficacy of organ-specific markers to identify the primary tumor origin in epithelial bone metastases and we evaluated the prognosis between patients with a immunohistologically determined primary tumor origin, with those with an undetermined one. Results. Associations of cytokeratine 7 and cytokeratine 20 expression confirmed diagnosis in 51 out of the 58 patients (88%) with a known primary tumor (Cohen’s K test 0.79 SE 0.80, P < 0.0005). Immunohistochemical analysis also contributed to establish the diagnosis of patients with an unknown primary tumor, yielding diagnosis in 35 out of the 67 cases (52%). Patients with an immunochistologically undetermined primary tumor site presented a statisti­cally significant poorer prognosis. Conclusions. Cytokeratine 7 and cytokeratine20 are useful immunochistochemical markers in determining a pre­liminary evaluation of bone metastases. Organ-specific immunohistochemical markers have a reliable role in either suggesting or confirming the possible origin of metastases. An indeterminate immunohistochemical phenotype seems to relate to a less differentiated lesion, with a worse prognosis. Introduction. Metastases are the most common type of malignancy involving the bone, while bone is the third most frequent site for metastases, after the lung and liver. In some patients, previous medical history, physical and laboratory examination are not conclusive to identify the primary tumor site. In such cases a bone biopsy and im­munohistochemical analysis may contribute to the diagnosis, determination of appropriate treatment and evaluation of prognosis. In this study, we tried to evaluate the imunochistochemical expression in bone metastases. Material and methods. We reviewed 125 patients, with a mean age of 63 years, treated for bone metastases in our institution. All patients received palliative orthopaedic surgery for bone metastatic carcinoma. Fifty-eight patients had already an established diagnosis of the primary tumor, while 67 patients presented metastases with an unknown primary tumor origin. Immunohistochemical analysis was performed to intra-operative bone biopsy specimens. The expression of cytokeratine 7, cytokeratin 20 and the expression of a panel of other organ-specific markers were re­corded. In patients with a known primary tumor, we examined the relationship between the origin of metastases, as suggested by the cytokeratin phenotype, compared with the one indicated by the initial histological diagnosis. We also recorded the efficacy of organ-specific markers to identify the primary tumor origin in epithelial bone metastases and we evaluated the prognosis between patients with a immunohistologically determined primary tumor origin, with those with an undetermined one. Results. Associations of cytokeratine 7 and cytokeratine 20 expression confirmed diagnosis in 51 out of the 58 patients (88%) with a known primary tumor (Cohen’s K test 0.79 SE 0.80, P < 0.0005). Immunohistochemical analysis also contributed to establish the diagnosis of patients with an unknown primary tumor, yielding diagnosis in 35 out of the 67 cases (52%). Patients with an immunochistologically undetermined primary tumor site presented a statisti­cally significant poorer prognosis. Conclusions. Cytokeratine 7 and cytokeratine20 are useful immunochistochemical markers in determining a pre­liminary evaluation of bone metastases. Organ-specific immunohistochemical markers have a reliable role in either suggesting or confirming the possible origin of metastases. An indeterminate immunohistochemical phenotype seems to relate to a less differentiated lesion, with a worse prognosis

    Clocking the onset of bilayer coherence in a high-Tc{T}_{c} cuprate

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    In cuprates, a precursor state of superconductivity is speculated to exist above the critical temperature TC. Here we show via a combination of far-infrared ellipsometry and ultrafast broadband optical spectroscopy that signatures of such a state can be obtained via three independent observables in an underdoped sample of NdBa2Cu3O6+δ. The pseudogap correlations were disentangled from the response of laser-broken pairs by clocking their characteristic time scales. The onset of a superconducting precursor state was found at a temperature TONS>TC, consistent with the temperature scale identified via static optical spectroscopy. Furthermore, the temperature evolution of the coherent vibration of the Ba ion, strongly renormalized by the onset of superconductivity, revealed a pronounced anomaly at the same temperature TONS. The microscopic nature of such a precursor state is discussed in terms of preformed pairs and enhanced bilayer coherence

    Enhanced gas-liquid absorption through natural convection studied by neutron imaging

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    Heat release from absorption storage heat pump by means of absorption of water vapor into aqueous sodium hydroxide is limited by uptake kinetics affecting temperature gain, as well as power- and energy density of the method. Earlier studies pinpoint that natural diffusion alone is not sufficient to reach higher uptake rate, and that the surface to bulk exchange has to be enforced. In this paper, different technical solutions to this problem for the heat storage application are introduced and studied by neutron imaging, enabling visual observation of water vapor uptake and diffusion. The experiments brought to the fore that the buoyancy changes associated with water uptake may be utilized to markedly enhance kinetics. This concept was applied on a vertically installed spiral finned tube operating as heat and mass exchanger for the absorption storage heat pump, also referred to as sorption heat storage. By flooding the space between the spiral fin with absorbent, water absorption into the vertical surface leads to a buoyancy driven movement of the liquid, supplying unspent aqueous NaOH to the vertical surface and exchanging it with the diluted liquid. This is found to increase the rate of absorption markedly. Under realistic heat storage specific operating conditions, a temperature gain of 12.5 K, an active area specific power of 1.28 kW/m2 and an energy density of 243 kWh/m3 in respect to the volume of charged absorbent (greatest volume) is reached. It is proposed that carful design of the spiral finned tube to enhance buoyancy movement will further improve overall sorption heat storage performance

    Predicting lymphoma in Sjögren's syndrome and the pathogenetic role of parotid microenvironment through precise parotid swelling recording

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    Objective: Parotid swelling (PSW) is a major predictor of non-Hodgkin lymphoma (NHL) in primary Sjögren's syndrome (pSS). However, since detailed information on the time of onset and duration of PSW is scarce, this was investigated to verify whether it may lead to further improved prediction. NHL localisation was concomitantly studied to evaluate the role of the parotid gland microenvironment in pSS-related lymphomagenesis. Methods: A multicentre study was conducted among patients with pSS who developed B cell NHL during follow-up and matched controls that did not develop NHL. The study focused on the history of salivary gland and lachrymal gland swelling, evaluated in detail at different times and for different durations, and on the localisation of NHL at onset. Results: PSW was significantly more frequent among the cases: at the time of first referred pSS symptoms before diagnosis, at diagnosis, and from pSS diagnosis to NHL. The duration of PSW was evaluated starting from pSS diagnosis, and the NHL risk increased from PSW of 2-12 months to > 12 months. NHL was prevalently localised in the parotid glands of the cases. Conclusion: A more precise clinical recording of PSW can improve lymphoma prediction in pSS. PSW as a very early symptom is a predictor, and a longer duration of PSW is associated with a higher risk of NHL. Since lymphoma usually localises in the parotid glands, and not in the other salivary or lachrymal glands, the parotid microenvironment appears to be involved in the whole history of pSS and related lymphomagenesis

    Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe

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    The Extragalactic Background Light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the gamma-ray flux of extragalactic sources such as blazars and Gamma-Ray Bursts (GRBs). The Large Area Telescope onboard Fermi detects a sample of gamma-ray blazars with redshift up to z~3, and GRBs with redshift up to z~4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of gamma-ray flux attenuation by the EBL. We place upper limits on the gamma-ray opacity of the Universe at various energies and redshifts, and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. (2006) can be ruled out with high confidence.Comment: 42 pages, 12 figures, accepted version (24 Aug.2010) for publication in ApJ; Contact authors: A. Bouvier, A. Chen, S. Raino, S. Razzaque, A. Reimer, L.C. Reye

    Addressing the clinical unmet needs in primary Sjögren's Syndrome through the sharing, harmonization and federated analysis of 21 European cohorts

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    For many decades, the clinical unmet needs of primary Sjögren's Syndrome (pSS) have been left unresolved due to the rareness of the disease and the complexity of the underlying pathogenic mechanisms, including the pSS-associated lymphomagenesis process. Here, we present the HarmonicSS cloud-computing exemplar which offers beyond the state-of-the-art data analytics services to address the pSS clinical unmet needs, including the development of lymphoma classification models and the identification of biomarkers for lymphomagenesis. The users of the platform have been able to successfully interlink, curate, and harmonize 21 regional, national, and international European cohorts of 7,551 pSS patients with respect to the ethical and legal issues for data sharing. Federated AI algorithms were trained across the harmonized databases, with reduced execution time complexity, yielding robust lymphoma classification models with 85% accuracy, 81.25% sensitivity, 85.4% specificity along with 5 biomarkers for lymphoma development. To our knowledge, this is the first GDPR compliant platform that provides federated AI services to address the pSS clinical unmet needs. © 2022 The Author(s
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