Boundary time crystals

This work was supported in part by \Progetti Interni - Scuola Normale Superiore" (A.R.), EU- 691 QUIC (R.F. and A.R.), CRF Singapore Ministry of Education (CPR-QSYNC 692) (R.F.), EPSRC program TOPNES (EP/I031014/1) (J.K.).In this work we introduce boundary time crystals. Here continuous time-translation symmetry breaking occurs only in a macroscopic fraction of a many-body quantum system. After introducing their definition and properties, we analyze in detail a solvable model where an accurate scaling analysis can be performed. The existence of the boundary time crystals is intimately connected to the emergence of a time-periodic steady state in the thermodynamic limit of a many-body open quantum system. We also discuss connections to quantum synchronization.PostprintPeer reviewe

Evidence of coexistence of change of caged dynamics at Tg and the dynamic transition at Td in solvated proteins

Mossbauer spectroscopy and neutron scattering measurements on proteins embedded in solvents including water and aqueous mixtures have emphasized the observation of the distinctive temperature dependence of the atomic mean square displacements, , commonly referred to as the dynamic transition at some temperature Td. At low temperatures, increases slowly, but it assume stronger temperature dependence after crossing Td, which depends on the time/frequency resolution of the spectrometer. Various authors have made connection of the dynamics of solvated proteins including the dynamic transition to that of glass-forming substances. Notwithstanding, no connection is made to the similar change of temperature dependence of obtained by quasielastic neutron scattering when crossing the glass transition temperature Tg, generally observed in inorganic, organic and polymeric glass-formers. Evidences are presented to show that such change of the temperature dependence of from neutron scattering at Tg is present in hydrated or solvated proteins, as well as in the solvents used unsurprisingly since the latter is just another organic glass-formers. The obtained by neutron scattering at not so low temperatures has contributions from the dissipation of molecules while caged by the anharmonic intermolecular potential at times before dissolution of cages by the onset of the Johari-Goldstein beta-relaxation. The universal change of at Tg of glass-formers had been rationalized by sensitivity to change in volume and entropy of the beta-relaxation, which is passed onto the dissipation of the caged molecules and its contribution to . The same rationalization applies to hydrated and solvated proteins for the observed change of at Tg.Comment: 28 pages, 10 figures, 1 Tabl

Revealing the high-energy electronic excitations underlying the onset of high-temperature superconductivity in cuprates

In strongly-correlated systems the electronic properties at the Fermi energy (EF) are intertwined with those at high energy scales. One of the pivotal challenges in the field of high-temperature superconductivity (HTSC) is to understand whether and how the high energy scale physics associated with Mott-like excitations (|E-EF|>1 eV) is involved in the condensate formation. Here we show the interplay between the many-body high-energy CuO2 excitations at 1.5 and 2 eV and the onset of HTSC. This is revealed by a novel optical pump supercontinuum-probe technique, which provides access to the dynamics of the dielectric function in Y-Bi2212 over an extended energy range, after the photoinduced suppression of the superconducting pairing. These results unveil an unconventional mechanism at the base of HTSC both below and above the optimal hole concentration required to attain the maximum critical temperature (Tc)

Patellofemoral Joint Arthroplasty: Our Experience in Isolated Patellofemoral and Bicompartmental Arthritic Knees

Introduction Isolated patellofemoral (PF) arthritis is rare, and there is no complete agreement about the best surgical treatment. The operative treatments are total knee arthroplasty and patellofemoral replacement (PFR). The incidence of many early complications of PF arthroplasty has decreased with the introduction of newer designs. Nowadays, the main cause of revision surgery is the progression of tibiofemoral osteoarthritis. In the past, PF arthroplasty was contraindicated in patients with evidence of osteoarthritis or pain in medial or lateral tibiofemoral compartments. The improvement in implant designs and surgical techniques has allowed the addition of a monocompartmental arthroplasty for the medial or lateral tibiofemoral compartment. In this work, we evaluate our first experience with PF arthroplasty and its combination with unicompartmental knee arthroplasty. Materials and Methods From May 2014 to March 2016, we treated 14 patients. An isolated PF arthroplasty was performed in six knees (five patients), and a combined PF and unicompartmental knee arthroplasty was performed in nine cases. We observed a significant improvement in the clinical and functional Knee Society Scores (KSSs) after surgery in our patients. Results We obtained good results in our cases both for clinical and functional KSSs. Patellar clunk was recorded in one case. Discussion and Conclusion We are going toward a new attitude in which partial osteoarthritic changes could be treated with partial resurfacing prosthetic solutions such as unicompartmental, bi–unicompartmental or PFR alone, or unicompartmental combined, which respects the cruciates and achieves maximal bone preservation, which is vital, particularly, for young patients

Observing heme doming in myoglobin with femtosecond X-ray absorption spectroscopy

We report time-resolved X-ray absorption measurements after photolysis of carbonmonoxy myoglobin performed at the LCLS X-ray free electron laser with nearly 100 fs (FWHM) time resolution. Data at the Fe K-edge reveal that the photoinduced structural changes at the heme occur in two steps, with a faster (∼70 fs) relaxation preceding a slower (∼400 fs) one. We tentatively attribute the first relaxation to a structural rearrangement induced by photolysis involving essentially only the heme chromophore and the second relaxation to a residual Fe motion out of the heme plane that is coupled to the displacement of myoglobin F-helix

IPOMAGNESEMIA GRAVE CORRELATA ALL’ASSUNZIONE DI INIBITORE DI POMPA PROTONICA

Gli inibitori di pompa protonica (IPP) sono tra i farmaci più frequentemente assunti nella popolazione anziana, spesso cronicamente, anche per indicazioni non sempre giustificate. Sebbene siano farmaci ben tollerati, emergono sempre nuove e frequenti reazioni avverse. In particolare, negli ultimi anni, sono stati riportati vari case-report di ipomagnesemia insorta dopo terapia prolungata con IPP. Tuttavia, ad oggi, non è stato di-mostrato il meccanismo fisiopatologico con cui queste molecole possono indurre tale disionia. Il magnesio è il secondo catione più abbondante nella cellula e svolge ruoli chiave in molti processi intracellulari. La sua omeostasi è garantita dall’equilibrio tra l’assorbimento intestinale e l’escrezione (e riassorbimento) renale, non-ché dallo scambio con l’osso, che rappresenta più del-la metà dei suoi depositi. L’ipomagnesemia severa può causare tetania, convulsioni, aritmie cardiache, ipoparatiroidismo ed ipocalcemia/ipokaliemia. L’assorbi-mento del magnesio avviene nell’intestino in due modi: passivamente secondo gradiente di concentrazione (attraverso gli spazi paracellulari della mucosa nel piccolo intestino) e attivamente (quasi esclusivamente nel colon e nel tubulo contorto distale del rene) tramite dei trasportatori transcellulari saturabili, appartenenti alla famiglia delle proteine di canale (TRP) e chiamati TRPM6 e TRPM7. Si è ipotizzato che il deficit di magnesio associato a terapia con IPP possa essere dovuto più ad un malassorbimento intestinale del catione che ad una sua perdita renale, in quanto, nei casi riportati, la magnesuria è risultata ridotta. Descriviamo il caso di un uomo di 74 anni ricoverato presso l’U.O.C. di Geriatria del Policlinico Universitario di Palermo nel mese di marzo 2017 per grave ipocalcemia e ipomagnesemia

Ricerche nella catacomba di Villagrazia di Carini

The Quaderno Digitale 9 is dedicated to the archaeological researches conducted in the Early Christian catacomb of Villagrazia di Carini until year 2015. The essay of G. Schirò presents the results of the excavations carried out from 2008 to 2011 in the Gallery IX and the structural analysis of 36 burials. Marco Correra, in the second essay, presents the analysis of the types of closure of the tombs so far excavated, in comparison with other funerary contexts in Sicily, Sardinia and North Africa. Finally, Francesco Scirè and Marta Marescalchi illustrate the project drawn up for the enjoyment of the most representative sectors of the monument, whose visit was inaugurated in May 2015

IPERSENSIBILITÀ AL GLUTINE NELL’ANZIANO. PRESENTAZIONE DI UN CASO CLINICO

La celiachia è una malattia immunomediata scatenata dall’ingestione di glutine che, in soggetti geneticamente predisposti, determina un processo infiammatorio intestinale con conseguente malassorbimento e manifesta-zioni extraintestinali. Fino ad alcuni anni fa era considerata una patologia rara, tipica dell’età infantile; lo scenario epidemiologico della celiachia, oggi, è totalmente cambiato, grazie anche all’introduzione di test sierologici ad elevata sensibilità e specificità come gli anticorpi anti-endomisio (EMA) e gli anticorpi anti-transglutaminasi tissutale (tTG). Studi epidemiologici basati sull’impiego dei test sierologici hanno dimostrato che la diagnosi di celiachia viene sempre più effettuata in età adulta con un’età media di presentazione di 45 anni ed una distribuzione bimodale (un picco tra 1 e 5 anni, un secondo picco tra 20 e 50 anni). Il 20% delle diagnosi vengono poste in soggetti di età superiore ai 60 anni: sulla base di ciò, è importante pensare alla celiachia come categoria diagnostica nel paziente anziano. La celiachia va sospettata in presenza di diarrea persistente per oltre tre settimane, spesso notturna, steatorrea, meteorismo, addominalgia, calo ponderale, soprattutto se questi sintomi si associano a diselettrolitismi, carenza di oligoelementi e vitamine con crampi muscolari, dolori ossei ed edemi; bisogna sospettare la celiachia anche in presenza di segni e/o sintomi più aspecifici, che persistono nel tempo e per i quali non si rintraccia una causa evidente quali la dispepsia, sintomi tipo sindrome dell’intestino irritabile, anemia sideropenica, anemia macrocitica, ipertransaminasemia, osteoporosi, disturbi neurologici quali neuropatie, atassia ed epilessia con calcificazioni cerebrali. Descriviamo il caso di un paziente di 68 anni ricoverato per stato cachettico presso l’U.O.C. di Geriatria del Policlinico Universitario di Palermo nei mesi di novembre e dicembre 2014