New Results on the Phase Diagram of the FFXY Model: A Twisted CFT Approach

The issue of the number, nature and sequence of phase transitions in the fully frustrated XY (FFXY) model is a highly non trivial one due to the complex interplay between its continuous and discrete degrees of freedom. In this contribution we attack such a problem by means of a twisted conformal field theory (CFT) approach and show how it gives rise to the U (1)$\otimes Z_{2}$ symmetry and to the whole spectrum of excitations of the FFXY model.Comment: 7 pages; talk given by G. Niccoli at "Path Integrals - New Trends and Perspectives International Conference", Max-Planck-Institut, Dresden, Germany, September 23 - 28, 200

Non-diagonal open spin-1/2 XXZ quantum chains by separation of variables: Complete spectrum and matrix elements of some quasi-local operators

The integrable quantum models, associated to the transfer matrices of the 6-vertex reflection algebra for spin 1/2 representations, are studied in this paper. In the framework of Sklyanin's quantum separation of variables (SOV), we provide the complete characterization of the eigenvalues and eigenstates of the transfer matrix and the proof of the simplicity of the transfer matrix spectrum. Moreover, we use these integrable quantum models as further key examples for which to develop a method in the SOV framework to compute matrix elements of local operators. This method has been introduced first in [1] and then used also in [2], it is based on the resolution of the quantum inverse problem (i.e. the reconstruction of all local operators in terms of the quantum separate variables) plus the computation of the action of separate covectors on separate vectors. In particular, for these integrable quantum models, which in the homogeneous limit reproduce the open spin-1/2 XXZ quantum chains with non-diagonal boundary conditions, we have obtained the SOV-reconstructions for a class of quasi-local operators and determinant formulae for the covector-vector actions. As consequence of these findings we provide one determinant formulae for the matrix elements of this class of reconstructed quasi-local operators on transfer matrix eigenstates.Comment: 40 pages. Minor modifications in the text and some notations and some more reference adde

DENS INVAGINATUS (DENS IN DENTE): A MULTIDISCIPLINARY APPROACH. CASE REPORT

Aim: The purpose of this report was to demonstrate how a multidisciplinary surgical and endodontic approach in this type of tooth anomaly, may improve the prognosis both functionally and aesthetically. Dens invaginatus is a developmental anomaly resulting from infolding of the surface of the tooth crown before calcification has occurred. Many mechanisms have been proposed as a cause of this phenomenon, including local delay in enamel formation, infolding of the enamel organ within the dental pulp and local external influences on the tooth germ, but the aetiology of dens in dente is still not entirely known. The most common teeth interested by this malformation are maxillary lateral incisors, sometimes it occurs bilaterally. Morphologically the malformation is classified in three types: Type I: An enamel-lined minor invagination occurring within the crown not extending beyond the amelocemental junction. Type II: An enamel-lined form that invades the root but remains confined as a blind sac. It may or not communicate with dental pulp. Type III: a form that penetrates through the root perforating at the apical area showing “a second foramen” in the apical or periodontal area. There is no immediate communication with the pulp. The invagination may be completely lined by enamel, but frequently cementum will be found lining the invagination. The invagination commonly communicates with the oral cavity, allowing the entry of irritants and microorganisms either to the pulpal tissue or to an area that is only separated from pulpal tissue by a thin layer of dentin or enamel. This continual admission of irritants and the consequent inflammation usually leads to necrosis of the adjacent pulpal tissue and induces a periodontal or apical abscess. Other reported sequels of undiagnosed and untreated invaginated teeth include cysts, delay eruption and internal resorption. Sometimes Dens in Dente is associated with dental anomalies like taurodontia, microdontia, supernumerary teeth, gemination, and dentinogenesis imperfecta. Description and procedures: A 24- year old male patient came to the Dental Clinic for aesthetic reasons. Intraoral examination disclosed the presence of a maxillary right lateral incisor with unusual morphological features. The crown of the tooth had a peg-shaped appearance. Radiological evaluation showed that a large periapical lesion existed corresponding to the area of the lateral incisor, and irregular root canal borders and an enamel-lined invagination extended through the root. A Type III Dens Invaginatus was diagnosed. The patient was invited to have a maxillary Dental Scan done that showed exactly the wideness of the bone loss. After several irrigations with 5% NaClO, the endodontic treatment was performed: Ca(OH)2 was left in the root canal for one month and then Thermafil Obturators (Dentsply, Maillefer) were used for endodontic closure. After eight months, although the initial improvement , we decided for the surgical removal of the cysts and apicectomy of the tooth. Conclusion: Dens invaginatus has an unpredictable root canals anatomy. For a good clinical outcome we need to associate the surgical approach with the endodontic treatment

Rationale, experimental data, and emerging clinical evidence on early and preventive use of levosimendan in patients with ventricular dysfunction

Acute ventricular dysfunction (AVD) is a complex condition with substantial morbidity and mortality, still featuring unique therapeutic challenges. Levosimendan is a calcium sensitizer and ATP-dependent potassium channel opener that was developed as an inodilating drug for the treatment of acute heart failure and cardiogenic shock. Differently from other more widely used inotropic agents, levosimendan has some exclusive characteristics, in terms of mechanisms of action, pharmacodynamic profile, and haemodynamic effects. This may have important clinical implications. In particular, in patients with AVD or in patients with pre-existing severe ventricular impairment undergoing planned myocardial stress, the administration of levosimendan before the onset of overt symptoms or before cardiovascular therapeutic procedures may have the potential to bridge the patient through the critical phase. In this review, we will focus on the rationale, the existing experimental data, and the emerging clinical experience supporting an early, even preventive use of levosimendan in severe ventricular dysfunction, beyond its recognized indications

Antiperiodic dynamical 6-vertex model I: Complete spectrum by SOV, matrix elements of the identity on separate states and connections to the periodic 8-vertex model

The spin-1/2 highest weight representations of the dynamical 6-vertex and the standard 8-vertex Yang-Baxter algebra on a finite chain are considered in this paper. For the antiperiodic dynamical 6-vertex transfer matrix defined on chains with an odd number of sites, we adapt the Sklyanin's quantum separation of variable (SOV) method and explicitly construct SOV representations from the original space of representations. We provide the complete characterization of eigenvalues and eigenstates proving also the simplicity of its spectrum. Moreover, we characterize the matrix elements of the identity on separated states by determinant formulae. The matrices entering in these determinants have elements given by sums over the SOV spectrum of the product of the coefficients of separate states. This SOV analysis is not reduced to the case of the elliptic roots of unit and the results here derived define the required setup to extend to the dynamical 6-vertex model the approach recently developed in [1]-[5] to compute the form factors of the local operators in the SOV framework, these results will be presented in a future publication. For the periodic 8-vertex transfer matrix, we prove that its eigenvalues have to satisfy a fixed system of equations. In the case of a chain with an odd number of sites, this system of equations is the same entering in the SOV characterization of the antiperiodic dynamical 6-vertex transfer matrix spectrum. This implies that the set of the periodic 8-vertex eigenvalues is contained in the set of the antiperiodic dynamical 6-vertex eigenvalues. A criterion is introduced to find simultaneous eigenvalues of these two transfer matrices and associate to any of such eigenvalues one nonzero eigenstate of the periodic 8-vertex transfer matrix by using the SOV results. Moreover, a preliminary discussion on the degeneracy of the periodic 8-vertex spectrum is also presented.Comment: 36 pages, main modifications in section 3 and one appendix added, no result modified for the dynamical 6-vertex transfer matrix spectrum and the matrix elements of identity on separate states for chains with an odd number of site

C9orf72 repeat expansions cause neurodegeneration in Drosophila through arginine-rich proteins

An expanded GGGGCC repeat in C9orf72 is the most common genetic cause of frontotemporal dementia and amyotrophic lateral sclerosis. A fundamental question is whether toxicity is driven by the repeat RNA itself and/or by dipeptide repeat proteins generated by repeat-associated, non-ATG translation. To address this question we developed in vitro and in vivo models to dissect repeat RNA and dipeptide repeat protein toxicity. Expression of pure repeats in Drosophila caused adult-onset neurodegeneration attributable to poly-(glycine-arginine) proteins. Thus, expanded repeats promoted neurodegeneration through neurotoxic proteins. Expression of individual dipeptide repeat proteins with a non-GGGGCC RNA sequence showed both poly-(glycine-arginine) and poly-(proline-arginine) proteins caused neurodegeneration. These findings are consistent with a dual toxicity mechanism, whereby both arginine-rich proteins and repeat RNA contribute to C9orf72-mediated neurodegeneration

Topological order in Josephson junction ladders with Mobius boundary conditions

We propose a CFT description for a closed one-dimensional fully frustrated ladder of quantum Josephson junctions with Mobius boundary conditions, in particular we show how such a system can develop topological order. Such a property is crucial for its implementation as a "protected" solid state qubit.Comment: 14 pages, 3 figures, to appear in JSTA

The 9p21 Rs 1333040 polymorphism is associated with coronary microvascular obstruction in ST-segment elevation myocardial infarction treated by primary angioplasty

Background: Microvascular obstruction (MVO) after primary percutaneous coronary intervention (pPCI) leads to higher incidence of both early and late complications. A number of single nucleotide polymorphisms in 9p21 chromosome have been shown to affect angiogenesis in response to ischaemia. In particular, Rs1333040 with its three genotypic vriants C/C, T/C and T/T might influence the occurrence of MVO after pPCI. Methods: We enrolled ST-elevation myocardial infarction (STEMI) patients undergoing pPCI. The Rs1333040 polymorphism was evaluated by polymerase chain reaction-restriction fragment length polymorphism using restriction endonucleases (Bsml). Two expert operators unaware of the patients' identity performed the angiographic analysis; collaterals were assessed applying Rentrop's classification. Angiographic MVO was defined as a post-pPCI Thrombolysis In Myocardial Infarction (TIMI)<3 or TIMI 3 with myocardial blush grade 0 or 1, whereas electrocardiographic MVO was defined as ST segment resolution Results: Among our 133 STEMI patients (mean age 63 +/- 11 years, men 72%), 35 (26%) and 53 (40%) respectively experienced angiographic or electrocardiographic MVO. Angiographic and electrocardiographic MVO were different among the three variants (p= 0.03 and p=0.02 respectively). In particular, T/T genotype was associated with a higher incidence of both angiographic and electrocardiographic MVO compared with C/C genotype (p=0.04 and p=0.03 respectively). Moreover, Rentrop score <2 detection rate differed among the three genotypes (p=0.03). In particular T/T genotype was associated with a higher incidence of a Rentrop score <2 as compared with C/C genotype (p= 0.02). Conclusion: Rs1333040 polymorphism genetic variants portend different MVO incidence. In particular, T/T genotype is related to angiographic and electrocardiographic MVO and to worse collaterals towards the culprit artery

Alcohol Septal Ablation for Hypertrophic Obstructive Cardiomyopathy: A Contemporary Reappraisal

Percutaneous alcohol septal ablation (ASA) is an effective and minimally invasive therapeutic strategy to resolve left ventricular outflow tract obstruction (LVOTO) in patients with hypertrophic cardiomyopathy who remain symptomatic on maximally tolerated medical therapy. First performed by Sigwart in 1994, the procedure consists in determining an iatrogenic infarction of the basal interventricular septum to reduce LVOTO and alleviate symptoms. Since its first description, numerous studies have demonstrated its efficacy and safety, proposing ASA as a valid and attractive alternative to surgical septal myectomy. The success rate of the intervention is profoundly affected by patient selection and centre experience. In this review, we sought to summarise current evidence on ASA, describing the procedure and proposing a cardiomyopathy team-based approach to resolve clinical disputes in clinical practice