370 research outputs found

    Superselection Structure of Massive Quantum Field Theories in 1+1 Dimensions

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    We show that a large class of massive quantum field theories in 1+1 dimensions, characterized by Haag duality and the split property for wedges, does not admit locally generated superselection sectors in the sense of Doplicher, Haag and Roberts. Thereby the extension of DHR theory to 1+1 dimensions due to Fredenhagen, Rehren and Schroer is vacuous for such theories. Even charged representations which are localizable only in wedge regions are ruled out. Furthermore, Haag duality holds in all locally normal representations. These results are applied to the theory of soliton sectors. Furthermore, the extension of localized representations of a non-Haag dual net to the dual net is reconsidered. It must be emphasized that these statements do not apply to massless theories since they do not satisfy the above split property. In particular, it is known that positive energy representations of conformally invariant theories are DHR representations.Comment: latex2e, 21 pages. Final version, to appear in Rev. Math. Phys. Some improvements of the presentation, but no essential change

    Handheld-Impedance-Measurement System with seven-decade capability and potentiostatic function

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    This paper describes design and test of a new impedance-measurement system for nonlinear devices that exhibits a seven-decade range and works down to a frequency of 0.01 Hz. The system is specifically designed for electrochemical measurements, but the proposed architecture can be employed in many other fields where flexible signal generation and analysis are required. The system employs an unconventional signal generator based on two pulsewidth modulation (PWM) oscillators and an autocalibration system that allows uncertainties of less than 3% to be obtained over a range of 1 kΩ to 100 GΩ. A synchronous demodulation processing allows the noise superimposed to the low-amplitude input signals to be made negligibl

    The current landscape of imaging recommendations in cardiovascular clinical guidelines: toward an imaging-guided precision medicine

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    The purpose of this article is to provide an overview on the role of CT scan and MRI according to selected guidelines by the European Society of Cardiology (ESC) and the American College of Cardiology/American Heart Association (ACC/AHA). ESC and ACC/AHA guidelines were systematically reviewed for recommendations to CT and MRI use in specific cardiovascular (CV) clinical categories. All recommendations were collected in a dataset, including the class of recommendation, the level of evidence (LOE), the specific imaging technique, the clinical purpose of the recommendation and the recommending Society. Among the 43 included guidelines (ESC: n = 18, ACC/AHA: n = 25), 26 (60.4%) contained recommendations for CT scan or MRI (146 recommendations: 62 for CT and 84 for MRI). Class of recommendation IIa (32.9%) was the most represented, followed by I (28.1%), IIb (24%) and III (11.9%). MRI recommendations more frequently being of higher class (I: 36.9%, IIa: 29.8%, IIb: 21.4%, III: 11.9%) as compared to CT (I: 16.1%, IIa: 37.1%, IIb: 27.4%, III: 19.4%). Most of recommendation (55.5%) were based on expert opinion (LOE C). The use of cardiac CT and cardiac MR in the risk assessment, diagnosis, therapeutic and procedural planning is in continuous development, driven by an increasing need to evolve toward an imaging-guided precision medicine, combined with cost-effectiveness and healthcare sustainability. These developments must be accompanied by an increased availability of high-performance scanners in healthcare facilities and should emphasize the need of increasing the number of radiologists fully trained in cardiac imaging

    Role of toll-like receptors in actuating stem/progenitor cell repair mechanisms: Different functions in different cells

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    Toll-like receptors (TLRs) represent one of the bridges that regulate the cross-talk between the innate and adaptive immune systems. TLRs interact with molecules shared and preserved by the pathogens of origin but also with endogenous molecules (damage/danger-associated molecular patterns (DAMPs)) that derive from injured tissues. This is probably why TLRs have been found to be expressed on several kinds of stem/progenitor cells (SCs). In these cells, the role of TLRs in the regulation of the basal motility, proliferation, differentiation processes, self-renewal, and immunomodulation has been demonstrated. In this review, we analyze the many different functions that the TLRs assume in SCs, pointing out that they can have different effects, depending on the background and on the kind of ligands that they recognize. Moreover, we discuss the TLR involvement in the response of SC to specific tissue damage and in the reparative processes, as well as how the identification of molecules mediating the differential function of TLR signaling could be decisive for the development of new therapeutic strategies. Considering the available studies on TLRs in SCs, here we address the importance of TLRs in sensing an injury by stem/progenitor cells and in determining their behavior and reparative activity, which is dependent on the conditions. Therefore, it could be conceivable that SCs employed in therapy could be potentially exposed to TLR ligands, which might modulate their therapeutic potential in vivo. In this context, to modulate SC proliferation, survival, migration, and differentiation in the pathological environment, we need to better understand the mechanisms of action of TLRs on SCs and learn how to control these receptors and their downstream pathways in a precise way. In this manner, in the future, cell therapy could be improved and made safer

    Genetic variants in the NOTCH4 gene influence the clinical features of migraine

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    BACKGROUND: Recent studies suggested an important role for vascular factors in migraine etiopathogenesis. Notch4 belongs to a family of transmembrane receptors that play an important role in vascular development and maintenance. The aim of this study was to test the hypothesis that polymorphisms of the NOTCH4 gene would modify the occurrence and the clinical features of migraine. FINDINGS: Using a case–control strategy, we genotyped 239 migraine patients and 264 controls for three different non-synonymous polymorphisms (T320A, G835V, R1346P) of the NOTCH4 gene and for the (CTG) n-encoding polyleucine polymorphism in exon 1. Although the analyzed polymorphisms resulted not associated with migraine, the clinical characteristics of our patients were significantly influenced by the different NOTCH4 genotypes. Longer duration of disease and severity of neurovegetative symptoms during headache attacks were associated with the R1346P and G835V polymorphisms, respectively. In female patients, worsening of migraine symptoms at menarche was significantly correlated with T320A polymorphism. CONCLUSIONS: Our study shows that genetic variations within the NOTCH4 gene significantly modify the clinical characteristics of migraine and may have a role in disease pathogenesis

    Intelligent non-colorimetric indicators for the perishable supply chain by non-wovens with photo-programmed thermal response

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    Spoiled perishable products, such as food and drugs exposed to inappropriate temperature, cause million illnesses every year. Risks range from intoxication due to pathogen-contaminated edibles, to suboptimal potency of temperature-sensitive vaccines. High-performance and low-cost indicators are needed, based on conformable materials whose properties change continuously and irreversibly depending on the experienced time-temperature profile. However, these systems can be limited by unclear reading, especially for colour-blind people, and are often difficult to be encoded with a tailored response to detect excess temperature over varying temporal profiles. Here we report on optically-programmed, non-colorimetric indicators based on nano-textured non-wovens encoded by their cross-linking degree. This combination allows a desired time-temperature response to be achieved, to address different perishable products. The devices operate by visual contrast with ambient light, which is explained by backscattering calculations for the complex fibrous material. Optical nanomaterials with photo-encoded thermal properties might establish new design rules for intelligent labels

    Melorheostosis and Osteopoikilosis Clinical and Molecular Description of an Italian Case Series

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    Melorheostosis (MEL) is an uncommon, sclerosing disease, characterised by hyperostosis of long bones, resembling the flowing of candle wax. The disease is sporadic and the pathogenesis is still poorly understood. Occasionally, the same family can include individuals with MEL and Osteopoikilosis (OPK), a disease characterised by multiple round foci of increased bone density. LEMD3 gene mutations are related to OPK and Buschke\u2013Ollendorff Syndrome, a genetic condition in which an association between MEL, OPK and skin lesions is observed. In rare cases, LEMD3 mutations and recently mosaic MAP2K1 gene mutations have been correlated to MEL suggesting that somatic mosaicism could be causative of the disease. In this study, we described the clinical, radiological and molecular findings of 19 individuals with MEL and 8 with OPK and compared the results to the medical literature. The molecular analyses of this case series corroborate the available data in the medical literature, indicating that LEMD3 germline mutations are not a major cause of isolated MEL and reporting five further cases of OPK caused by LEMD3 germline mutations
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