Thermal behaviour of siliceous faujasite: further structural interpretation of negative thermal expansion

The high-temperature behaviour of siliceous faujasite (Si-Y) was investigated by in situ synchrotron Xray powder diffraction from room temperature up to 1123 K. This porous phase is remarkably stable when heated, and no phase transitions or changes in symmetry are observed. A marked negative thermal expansion (NTE), already reported in literature for a heating range from 25 to 573 K, was confirmed up to about 923 K. Above this temperature a positive thermal expansion was observed. Si-Y’s thermal behaviour was interpreted on the basis of the transverse thermal vibrations of the oxygen atoms involved in the T–O–T linkages and a series of other structural features characterizing the faujasite structure, namely the T–T distances between adjacent tetrahedral sites, the thickness of the double 6-membered rings, and the ditrigonal index of the 6-membered rings. Moreover, the thermal behaviour of several other anhydrous porous materials with NTE behaviour is discussed and compared to that of Si-Y

Elastic behavior and high pressure-induced phase transition in chabazite: new data from a sample from Nova Scotia

Recently, the high pressure (HP) behavior of a natural chabazite from Vallerano [1] (VALL), and on the synthetic phases SAPO-34 [1] and ALPO-34 [2], was investigated in the frame of a wider project aimed at understanding the role of the framework/extraframework content on the compressibility of CHA-type porous materials. In this work, further structural information is obtained studying the response to HP of another natural chabazite sample from Nova Scotia (Canada) (NS) (s.g. R-3mR [3]), characterized by a different chemical composition with respect to VALL. The study was performed by means of in situ synchrotron X-ray powder diffraction (XRPD) and silicone oil as non-penetrating P-transmitting medium. XRPD experiments were performed in DAC at the BM01 beamline at ESRF (Grenoble, France) with a fixed =0.7355 Å. Powder patterns were collected from Pambup to 8.6 GPa and upon decompression. All the features of the Pamb pattern and the unit cell parameters are well recovered upon P release. Below 2.1 GPa, a and cell parameters slightly decrease and increase respectively with a resulting volume reduction of 3.6 %. Above 2.1 GPa, a transition to a triclinic P-1 pseudo-rhombohedral phase is observed. The rhombohedral to triclinic phase transition is accompanied by an abrupt decrease in the unit cell parameters and in the unit cell volume ( V=-4.0%). Between 2.5 and 5.9 GPa, the triclinic/pseudo-rhombohedral cell parameters decrease regularly and the unit cell volume variation ( V=-3.0%) indicates a lower compressibility with respect to that observed before the transition. In the highest P regime (5.9-7.2 GPa), a further slope change, with an increase in compressibility, is observed. As a whole, V between Pamb and 7.2 GPa is -12.6%. The elastic parameters, calculated with a second order BM-EoS, are V0 = 826 (1) Å3, K0 = 54(3) GPa and V0 = 784(2) Å3, K0 = 91(5) GPa, for the rhombohedral and triclinic phase, respectively. Preliminary results from Rietveld refinements up to about 1 GPa, suggest that the deformation mechanism acting in the low-P regime is a cooperative tilting of the tetrahedra belonging to the double 6-ring – resulting in a decrease of its thickness – accompanied by a simultaneous di-trigonalization of the two 6-rings. A similar mechanism was previously observed during compression of levyne [4]. The HP-induced cell volume contraction of NS (12.6 %) is higher than that of VALL (10.3%) in the same P range. This is congruent with the lower content in large extraframework potassium cations of NS, which contribute to sustain the porous structure in VALL

Synthesis of Ternary Borocarbonitrides by High Temperature Pyrolysis of Ethane 1,2-Diamineborane

Ethane 1,2-diamineborane (EDAB) is an alkyl-containing amine-borane adduct with improved hydrogen desorption properties as compared to ammonia borane. In this work, it is reported the high temperature thermolytic decomposition of EDAB. Thermolysis of EDAB has been investigated by concomitant thermogravimetry-differential thermal analysis-mass spectrometry experiments. EDAB shows up to four H2 desorption events below 1000 °C. Small fractions of CH4, C2H4 and CO/CO2 are also observed at moderate-high temperatures. The solid-state thermolysis product has been characterized by means of different structural and chemical methods, such as X-ray diffraction, Raman spectroscopy, Scanning electron microscopy, Elemental analysis, and X-ray photoelectron spectroscopy (XPS). The obtained results indicate the formation of a ternary borocarbonitride compound with a poorly-crystalline graphitic-like structure. By contrast, XPS measurements show that the surface is rich in carbon and nitrogen oxides, which is quite different to the bulk of the materialSome authors (Fabrice Leardini, Lorenzo Massimi, Maria Grazia Betti and Carlo Mariani) also thank Sapienza Università di Roma for financial support under “Progetti di Ateneo”, and the Italian Ministry of Education and Research (MIUR) for the PRIN grant “GRAF” n. 20105ZZTS

INFN What Next: Ultra-relativistic Heavy-Ion Collisions

This document was prepared by the community that is active in Italy, within INFN (Istituto Nazionale di Fisica Nucleare), in the field of ultra-relativistic heavy-ion collisions. The experimental study of the phase diagram of strongly-interacting matter and of the Quark-Gluon Plasma (QGP) deconfined state will proceed, in the next 10-15 years, along two directions: the high-energy regime at RHIC and at the LHC, and the low-energy regime at FAIR, NICA, SPS and RHIC. The Italian community is strongly involved in the present and future programme of the ALICE experiment, the upgrade of which will open, in the 2020s, a new phase of high-precision characterisation of the QGP properties at the LHC. As a complement of this main activity, there is a growing interest in a possible future experiment at the SPS, which would target the search for the onset of deconfinement using dimuon measurements. On a longer timescale, the community looks with interest at the ongoing studies and discussions on a possible fixed-target programme using the LHC ion beams and on the Future Circular Collider.Comment: 99 pages, 56 figure

Knowledge sharing in temporary teams: Exploring the use of 3D printing in orthopaedic surgery

This study explores knowledge sharing in temporary teams which use 3D printing technology to support surgical interventions. We focus on the planning phase of orthopaedic surgeries when senior surgeons organise a temporary team to create personalised treatment using 3D printing technology. We conduct in-depth interviews with 25 surgeons and their teams in one of the leading orthopaedic research hospitals in Italy. Based on our qualitative evidence, we find that when the technology provides a basis for the surgical planning, knowledge sharing in teams mostly occurs through two-way – dyadic – relationships between team participants. Our findings also demonstrate that hierarchy within teams is important to support the formation of dyads thereby facilitating knowledge sharing practices within temporary teams. This study is novel in highlighting how temporary teams deal with knowledge sharing challenges due to the continuous changes in team composition in healthcare

Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 $< p_{\rm{T}, assoc} < p_{\rm{T}, trig} <$ 5.0 GeV/$c$ is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range $|\eta|<0.9$. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161

Activity of a Pediatric Emergency Department of a Tertiary Center in Bologna, Italy, during SARS-CoV-2 Pandemic

During the SARS-CoV-2 pandemic, the pediatric emergency department (ED) of Bologna, Emilia-Romagna, Italy faced a reorganization to better deal with the new clinical needs. We herein describe the main changes in the organization and in the attendances to our pediatric ED. From the 1 March 2020 to the 31 January 2022, 796 children positive for SARS-CoV-2 presented to our pediatric ED, but only 26 required hospitalizations, of which only 9 for COVID-19 related reasons. During this period, we also registered a temporal correlation between multisystem inflammatory syndrome in children (MIS-C) admissions and the peaks of SARS-CoV-2 infection in the Italian population. Respiratory syncytial virus (RSV) remained during last year the viral infection with the highest hospitalization rate. The analysis and description of the changes in the activity of the pediatric ED during the SARS-CoV-2 pandemic may help to better understand the routinary activity and be prepared for any possible new challenge

Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider

Measurements of multi-particle azimuthal correlations (cumulants) for charged particles in p-Pb and Pb-Pb collisions are presented. They help address the question of whether there is evidence for global, flow-like, azimuthal correlations in the p-Pb system. Comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in p-Pb collisions. However, when a $|\Delta \eta|$ gap is placed to suppress such correlations, the two-particle cumulants begin to rise at high-multiplicity, indicating the presence of global azimuthal correlations. The Pb-Pb values are higher than the p-Pb values at similar multiplicities. In both systems, the second harmonic four-particle cumulants exhibit a transition from positive to negative values when the multiplicity increases. The negative values allow for a measurement of $v_{2}\{4\}$ to be made, which is found to be higher in Pb-Pb collisions at similar multiplicities. The second harmonic six-particle cumulants are also found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find $v_{2}\{4\} \simeq v_{2}\{6\}\neq 0$ which is indicative of a Bessel-Gaussian function for the $v_{2}$ distribution. For very high-multiplicity Pb-Pb collisions, we observe that the four- and six-particle cumulants become consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and Pb-Pb are measured. These are found to be similar for overlapping multiplicities, when a $|\Delta\eta| > 1.4$ gap is placed.Comment: 25 pages, 11 captioned figures, 3 tables, authors from page 20, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/87

Analysis of clinical profiles, deformities, and plantar pressure patterns in diabetic foot syndrome

Diabetic foot syndrome refers to heterogeneous clinical and biomechanical profiles, which render predictive models unsatisfactory. A valuable contribution may derive from identification and descriptive analysis of well-defined subgroups of patients. Clinics, biology, function, gait analysis, and plantar pressure variables were assessed in 78 patients with diabetes. In 15 of them, the 3D architecture of the foot bones was characterized by using weight-bearing CT. Patients were grouped by diabetes type (T1, T2), presence (DN) or absence (DNN) of neuropathy, and obesity. Glycated hemoglobin (HbA1c) and plantar lesions were monitored during a 48-month follow-up. Statistical analysis showed significant differences between the groups for at least one clinical (combined neuropathy score, disease duration, HbA1c), biological (age, BMI), functional (joint mobility, foot alignment), or biomechanical (regional peak pressure, pressure-time integral, cadence, velocity) variable. Twelve patients ulcerated during follow-up (22 lesions in total), distributed in all groups but not in the DNN T2 non-obese group. These showed biomechanical alterations, not always occurring at the site of lesion, and HbA1c and neuropathy scores higher than the expected range. Three of them, who also had weight-bearing CT analysis, showed &gt;40% of architecture parameters outside the 95%CI. Appropriate grouping and profiling of patients based on multi-instrumental clinical and biomechanical analysis may help improve prediction modelling and management of diabetic foot syndrome