39 research outputs found

    Topological transitions of the generalized Pancharatnam-Berry phase

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    Distinctfrom the dynamicalphase,in a cyclicevolution,a system’sstate may acquire an additionalcomponent,a.k.a.geometricphase.Recently, it has beendemonstrated that geometricphasescan be inducedby a sequenceof generalizedmeasurementsimplementedon a singlequbit.Furthermore, it has beenpredictedthat thesegeometricphasesmay exhibita topologicaltransitionas a functionof the measurementstrength.We demon-strate and studythis transitionexperimentallyby usingan opticalplatformwhere the qubitis representedbythe polarization of lightand the weak measurementis performedby meansof couplingwiththe spatial degreeof freedom.Our protocolcan be interpretedin termsof environment-inducedgeometricphases,whosevaluesare topologicallydeterminedby the environment-system couplingstrength.Our resultsshow that the two limitsof geometricphaseinducedby sequencesof eitherweak or projective measurementsare topologicallydistinct

    Diffuse Calcifications Protect Carotid Plaques regardless of the Amount of Neoangiogenesis and Related Histological Complications

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    Background. Neoangiogenesis is crucial in plaque progression and instability. Previous data from our group showed that Nestin-positive intraplaque neovessels correlated with histological complications. The aim of the present work is to evaluate the relationship between neoangiogenesis, plaque morphology, and clinical instability of the plaque. Materials and Methods. Seventy-three patients (53 males and 20 females, mean age 71 years) were consecutively enrolled. Clinical data and 14 histological variables, including intraplaque hemorrhage and calcifications, were collected. Immunohistochemistry for CD34 and Nestin was performed. RT-PCR was performed to evaluate Nestin mRNA (including 5 healthy arteries as controls). Results. Diffusely calcified plaques (13/73) were found predominantly in females (P=0.017), with a significantly lower incidence of symptoms (TIA/stroke (P=0.019) than noncalcified plaques but with the same incidence of histological complications (P=0.156)). Accordingly, calcified and noncalcified plaques showed similar mean densities of positivity for CD34 and Nestin. Nestin density, but not CD34, correlated with the occurrence of intraplaque hemorrhage. Conclusions. Plaques with massive calcifications show the same incidence of histological complications but without influencing symptomatology, especially in female patients, and regardless of the amount of neoangiogenesis. These results can be applied in a future presurgical identification of patients at major risk of developing symptoms

    The Heterogeneity of Skewness in T2W-Based Radiomics Predicts the Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer

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    Our study aimed to investigate whether radiomics on MRI sequences can differentiate responder (R) and non-responder (NR) patients based on the tumour regression grade (TRG) assigned after surgical resection in locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (nCRT). Eighty-five patients undergoing primary staging with MRI were retrospectively evaluated, and 40 patients were finally selected. The ROIs were manually outlined in the tumour site on T2w sequences in the oblique-axial plane. Based on the TRG, patients were grouped as having either a complete or a partial response (TRG = (0,1), n = 15). NR patients had a minimal or poor nCRT response (TRG = (2,3), n = 25). Eighty-four local first-order radiomic features (RFs) were extracted from tumour ROIs. Only single RFs were investigated. Each feature was selected using univariate analysis guided by a one-tailed Wilcoxon rank-sum. ROC curve analysis was performed, using AUC computation and the Youden index (YI) for sensitivity and specificity. The RF measuring the heterogeneity of local skewness of T2w values from tumour ROIs differentiated Rs and NRs with a p-value ≈ 10−5; AUC = 0.90 (95%CI, 0.73–0.96); and YI = 0.68, corresponding to 80% sensitivity and 88% specificity. In conclusion, higher heterogeneity in skewness maps of the baseline tumour correlated with a greater benefit from nCR

    Liver and intestinal protective effects of Castanea sativa Mill. bark extract in high-fat diet rats

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    The effects of Castanea sativa Mill. have been studied in high fat diet (HFD) overweight rats. Natural Extract of Chestnut bark (Castanea sativa Mill.) (ENCÂź), rich in ellagitannins, has been studied in 120 male Sprague-Dawley rats, divided in four groups. Two groups were controls: regular (RD) and HDF diet. Two groups received ENCÂź(20 mg/kg/day): RD + ENCÂźand HFD + ENCÂź. At baseline and at 7, 14 and 21 days, weight gain, serum lipids, plasma cytokines, liver histology, microsomial enzymes and oxidation, intestinal oxidative stress and contractility were studied. HFD increased body weight, increased pro-inflammatory cytokines, induced hepatocytes microvescicular steatosis, altered microsomial, increased liver and intestinal oxidative stress, deranged intestinal contractility. In HFD-fed rats, ENCÂźexerted antiadipose and antioxidative activities and normalized intestinal contractility, suggesting a potential approach to overweight management associated diseases

    Spin–orbit coupling induced by ascorbic acid crystals

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    Some anisotropic materials form semicrystalline structures, called spherulites, when observed in a polarisation microscope, exhibit a characteristic “maltese-cross”-like pattern. While this observation has been hitherto considered as a tool to characterize these materials, we show that these patterns are associated with a strong light’s spin–orbit coupling induced by the spherulite structures. We experimentally demonstrate these effects using samples of crystallized ascorbic acid and observing the creation of optical vortices in transmitted laser beams, as well as the formation of inhomogeneous polarisation patterns. Our findings suggest the use of some spherulites based on other materials in frequency ranges, e.g. in the THz domain, where polarisation and spatial shaping of electromagnetic radiation is still a challenging task

    Age-Related Mortality in STEMI Patients: Insight from One Year of HUB Centre Experience during the Pandemic

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    Background: Old patients have a poor prognosis when affected by ST elevation myocardial infarction (STEMI). The aim of our study was to evaluate the impact of age on acute and mid-term mortality in STEMI patients over one year in the pandemic period. Methods: we collected data on 283 STEMI patients divided into three groups according to age (not old, “Not-O”, ≤74 y/o; old, “O”, 75–84 y/o; very old, “Very-O”, ≥85 y/o). Results: the three groups did not differ in their clinical or procedural characteristics. The Very-O patients had a significantly increased incidence of in-hospital MACE (35%), mortality (30.0%), and percentage of cardiac death (25.0%). The only two independent predictors of in-hospital mortality were the ejection fraction (EF) [OR:0.902 (95% CI) 0.868–0.938; p < 0.0001] and COVID-19 infection [OR:3.177 (95% CI) 1.212–8.331; p = 0.019]. At follow-up (430 +/− days), the survival rates were decreased significatively among the age groups (Not-O 2.9% vs. O 14.8% vs. Very-O 28.6%; p < 0.0001), and the only two independent predictors of the follow-up mortality were the EF [OR:0.935 (95% CI) 0.891–0.982; p = 0.007] and age [OR:1.06 (95% CI) 1.018–1.110; p = 0.019]. Conclusions: in very old patients, all the accessory procedures that may be performed should be accurately and independently weighed up in terms of the risk–benefit balance and the real impact on the quality of life because of the poor mid-term prognosis

    Topological transitions of the generalized Pancharatnam-Berry phase

    No full text
    Distinct from the dynamical phase, in a cyclic evolution, a system’s state may acquire an additional component, a.k.a. geometric phase. Recently, it has been demonstrated that geometric phases can be induced by a sequence of generalized measurements implemented on a single qubit. Furthermore, it has been predicted that these geometric phases may exhibit a topological transition as a function of the measurement strength. We demonstrate and study this transition experimentally by using an optical platform where the qubit is represented by the polarization of light and the weak measurement is performed by means of coupling with the spatial degree of freedom. Our protocol can be interpreted in terms of environment-induced geometric phases, whose values are topologically determined by the environment-system coupling strength. Our results show that the two limits of geometric phase induced by sequences of either weak or projective measurements are topologically distinct

    Topological transitions of the generalized Pancharatnam-Berry phase

    No full text
    Distinct from the dynamical phase, in a cyclic evolution, a system’s state may acquire an additional component, a.k.a. geometric phase. Recently, it has been demonstrated that geometric phases can be induced by a sequence of generalized measurements implemented on a single qubit. Furthermore, it has been predicted that these geometric phases may exhibit a topological transition as a function of the measurement strength. We demonstrate and study this transition experimentally by using an optical platform where the qubit is represented by the polarization of light and the weak measurement is performed by means of coupling with the spatial degree of freedom. Our protocol can be interpreted in terms of environment-induced geometric phases, whose values are topologically determined by the environment-system coupling strength. Our results show that the two limits of geometric phase induced by sequences of either weak or projective measurements are topologically distinct

    Nestin and WT1 expression in small-sized vasa vasorum from human normal arteries

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    Introduction. Vasa vasorum (VV) neovasculogenic potential is now widely accepted, and possibly related to the presence of progenitor cells. We studied the morphology of VV in healthy arteries and their immunohistochemical (IHC) expression of Nestin and WT1, two markers of endothelial progenitor cells. Materials and Methods. Twenty arteries from 16 multiorgan donors were analyzed; IHC was performed manually (CD34, CD31, Nestin) or automatically (WT1). Microvessel positivity “density” for each antibody was calculated dividing vascular adventitia in 1-mm2 fields with an ocular micrometer. Double immunofluorescence was used to investigate Nestin and WT1 co-localization in VV. Results. The mean positivity “densities” for CD31, CD34, Nestin and WT1 were 13.63, 12.20, 8.90 and 7.98/mm2 respectively. Mean Nestin/CD31 and WT1/CD31 ratios were 0.69 and 0.63 respectively. VV <50 ”m in diameter showed a higher percentage of Nestin/WT1-positive cells than larger ones, especially in “hot spots”, characterized by several small-sized arteriolar VV, often together with nerva vasorum. Immunofluorescence indentified Nestin and WT1 in the same endothelial cells. WT1 nuclear expression was mainly seen in <50 ”m VV. Discussion. We describe Nestin and WT1 in adult VV, especially <50 ”m and gathered in “hot spots”. The nuclear localization of WT1 could express an increasing transcriptional activity in progenitor-committed Nestin-positive cells. The “hot spot” could therefore represent a valid model for the vasculogenic niche in normal arteries and could potentially represent the main source for neovasculogenesis during atherosclerosi
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