Diagnosing order by disorder in quantum spin systems

In this paper we study the frustrated J1-J2 quantum Heisenberg model on the square lattice for J2 > 2J1, in a magnetic field. In this regime the classical system is known to have a degenerate manifold of lowest energy configurations, where standard thermal order by disorder occurs. In order to study its quantum version we use a path integral formulation in terms of coherent states. We show that the classical degeneracy in the plane transverse to the magnetic field is lifted by quantum fluctuations. Collinear states are then selected, in a similar pattern to that set by thermal order by disorder, leaving a Z2 degeneracy. A careful analysis reveals a purely quantum mechanical effect given by the tunneling between the two minima selected by fluctuations. The effective description contains two planar (XY -like) fields conjugate to the total magnetization and the difference of the two sublattice magnetizations. Disorder in either or both of these fields produces the locking of their conjugate observables. Furthermore, within this scenario we argue that the quantum state is close to a product state.Comment: 8 pages, 3 figure

A neurally-interfaced hand prosthesis tuned inter-hemispheric communication

Purpose: This work investigates how a direct bidirectional connection between brain and hand prosthesis modifies the bi-hemispheric sensorimotor system devoted to the movement control of the lost limb. Hand prostheses are often unable to satisfy users' expectations, mostly due to the poor performance of their interfacing system. Neural Interfaces implanted inside nerves of the stump offer the advantage of using the bidirectional neural pathways 'naturally' dispatching signals to control proper hand actions and feed-back sensations. Learning to control a neurally-interfaced hand prosthesis and decode sensory information was previously observed to reduce the inter-hemispheric asymmetry of cortical motor maps and the clinical symptoms of phantom limb syndrome. Methods: Electroencephalographic (EEG) data was analysed using Functional Source Separation (FSS), a semi-blind method that incorporates prior knowledge about the signal of interest into data decomposition to give access to cortical patch activities. Results: Bi-hemispheric cortices showed normalization of their activity (topographical and spectral patterns) and of functional connectivity between homologous hand controlling areas, during the delivery of the motor command to the cybernetic prosthesis. Conclusions: The re-establishment of central-peripheral communication with the lost limb induced by a neurally-interfaced hand prosthesis produces beneficial plastic reorganization, not only restructuring contralateral directly-connected control areas, but also their functional balance within the bi-hemispheric system necessary for motor control

Sero-prevalence of West Nile virus in north-eastern Italy

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Imported cases of Chikungunya and Dengue fever in Emilia Romagna region, Italy

Imported cases of Chikungunya and Dengue fever in Emilia Romagna region, Italy F. Cavrini 1,∗, P. Gaibani2, C. Manisera3, A. Pierro4, G. Rossini 5, M.P. Landini 5, V. Sambri6 1 S. Orsola-Malpighi Hospital, BOLOGNA, Italy 2 S.Orsola-Malpighi Hospital, Section of Microbiology, BOLOGNA, Italy 3 S.Orsola-Malpighi Hospital, Section of Microbiology, BOLOGNA, Italy 4 S.Orsola-Malpighi, Bologna, Italy 5 S.Orsola-Malpighi Hospital, section of Microbiology, BOLOGNA, Italy 6 University of Bologna, Bologna, Ital

Serological update of the Chikungunya epidemic outbreak in Italy

Serological update of the Chikungunya epidemic outbreak in Italy P. Gaibani1,∗, A. Pierro1, F. CAVRINI2, G. Rossini 3, M.P. Landini 3, C. Manisera4, V. Sambri5 1 S.Orsola-Malpighi, Bologna, Italy 2 S. Orsola-Malpighi Hospital, BOLOGNA, Italy 3 S.Orsola-Malpighi Hospital, section of Microbiology, BOLOGNA, Italy 4 S.Orsola-Malpighi Hospital, Microbiology, Bologna, Italy 5 University of Bologna, Bologna, Ital

Serodiagnosis of visceral leishmaniasis in northeastern italy: Evaluation of seven serological tests

This study compares the performance of seven assays, including two ELISA (Leishmania ELISA IgG + IgM, Vircell Microbiologists; Leishmania infantum IgG ELISA, NovaTec), three rK39-based immunochromatographic tests (rK39-ICTs) (Leishmania Dipstick Rapydtest, Apacor; On Site Leishmania IgG/IgM Combo Rapid Test, CTK Biotech; LEISHMANIA Strip quick Test, Cypress Diagnostic), one indirect immunofluorescent antibody test (IFAT) (Leishmania-Spot IF, BioM\ue9rieux), and one western blot (WB) (Leishmania WESTERN BLOT IgG, LDBio Diagnostics) for serodiagnosis of visceral leishmaniasis (VL). Serum samples from 27 VL patients living in northeastern Italy were analyzed, as well as the serum samples from 50 individuals in whom VL diagnosis was excluded. The WB and the IFAT had 96% sensitivity, followed by the ELISA (63% and 74%, respectively). The rK39-ICT exhibited the worst performance among the serological tests, with sensitivities ranging from 52% to 70%. By combining selected ELISA/ICT, the sensitivity of VL detection reached 89%. IFAT and WB outperformed ELISA and rK39-ICT by possessing optimal sensitivity, but their high cost and complexity of execution would not allow their employment as screening tests. In conclusion, the combination of easy-to-perform tests, such as ICT and ELISA, could improve sensitivity in the serodiagnosis of Mediterranean VL

Volumetric Differences in Mapped Hippocampal Regions Correlate with Increase of High Alpha Rhythm in Alzheimer's Disease

Objective. The increase of high alpha relative to low alpha power has been recently demonstrated as a reliable EEG marker of hippocampal atrophy conversion of patients with mild cognitive impairment (MCI) in Alzheimer's disease (AD). In the present study we test the reliability of this EEG index in subjects with AD. Methods. Correlation between EEG markers and volumetric differences in mapped hippocampal regions was estimated in AD patients. Results. Results show that the increase of alpha3/alpha2 power ratio is correlated with atrophy of mapped hippocampal regions in Alzheimer's disease. Conclusions. The findings confirm the possible diagnostic role of EEG markers

Alginate Formulations: Current Developments in the Race for Hydrogel-Based Cardiac Regeneration

Cardiovascular diseases, including myocardial infarction (MI), represent the main worldwide cause of mortality and morbidity. In this scenario, to contrast the irreversible damages following MI, cardiac regeneration has emerged as a novel and promising solution for in situ cellular regeneration, preserving cell behavior and tissue cytoarchitecture. Among the huge variety of natural, synthetic, and hybrid compounds used for tissue regeneration, alginate emerged as a good candidate for cellular preservation and delivery, becoming one of the first biomaterial tested in pre-clinical research and clinical trials concerning cardiovascular diseases. Although promising results have been obtained, recellularization and revascularization of the infarcted area present still major limitations. Therefore, the demand is rising for alginate functionalization and its combination with molecules, factors, and drugs capable to boost the regenerative potential of the cardiac tissue. The focus of this review is to elucidate the promising properties of alginate and to highlight its benefits in clinical trials in relation to cardiac regeneration. The definition of hydrogels, the alginate characteristics, and recent biomedical applications are herewith described. Afterward, the review examines in depth the ongoing developments to refine the material relevance in cardiac recovery and regeneration after MI and presents current clinical trials based on alginate

The assessment of vertebral fractures in elderly women with recent hip fractures: the BREAK Study

Summary This study aimed to evaluate the prevalence of vertebral fractures in elderly women with a recent hip fracture. The burden of vertebral fractures expressed by the Spinal Deformity Index (SDI) is more strictly associated with the trochanteric than the cervical localization of hip fracture and may influence short-term functional outcomes. Introduction This study aimed to determine the prevalence and severity of vertebral fractures in elderly women with recent hip fracture and to assess whether the burden of vertebral fractures may be differently associated with trochanteric hip fractures with respect to cervical hip fractures. Methods We studied 689 Italian women aged 60 years or over with a recent low trauma hip fracture and for whom an adequate X-ray evaluation of spine was available. All radiographs were examined centrally for the presence of any vertebral deformities and radiological morphometry was performed. The SDI, which integrates both the number and the severity of fractures, was also calculated. Results Prevalent vertebral fractures were present in 55.7 % of subjects and 95 women (13.7 %) had at least one severe fracture. The women with trochanteric hip fracture showed higher SDI and higher prevalence of diabetes with respect to those with cervical hip fracture, p00.017 and p00.001, respectively. SDI, surgical menopause, family history of fragility fracture, and type2 diabetes mellitus were independently associated with the risk of trochanteric hip fracture. Moreover, a higher SDI was associated with a higher percentage of postsurgery complications (p00.05) and slower recovery (p<0.05). Conclusions Our study suggests that the burden of prevalent vertebral fractures is more strictly associated with the trochanteric than the cervical localisation of hip fracture and that elevated values of SDI negatively influence short term functional outcomes in women with hip fracture