The control of catalytic performance of rutile-type Sn/V/Nb/Sb mixed oxides, catalysts for propane ammoxidation to acrylonitrile

This paper describes the effect of the composition of rutile-type Sn/V/Nb/Sb mixed oxides catalysts on the catalytic performance in the gas-phase ammoxidation of propane to acrylonitrile. The variation in the atomic ratio between components in catalysts is the key for the control of activity and selectivity. In samples with atomic composition Sn/V/Nb/Sb 1/0.2/1/x (0 x 5) and 1/0.2/y/3 (0 y 3) several compounds formed, i.e., SnO2, Sb/Nbmixed oxide, Sb6O13 and non-stoichiometric rutile-type V/Nb/Sb/O; the latter segregated preferentially at the surface of the catalyst. Tin oxide provided the rutile matrix for the dispersion of the mixed oxides. The main role of Sb was shown to generate mixed oxides containing specific sites for the allylic ammoxidation of propylene intermediately formed. The presence of Nb enhanced the activity and selectivity of these sites

Vapor phase Beckmann rearrangement using high silica zeolite catalyst

Vapor phase Beckmann rearrangement of cyclohexanone oxime to e-caprolactam has been studied using high silica zeolite catalysts. Catalysts with different crystal sizes and gel-ageing times have been activated by ionic exchange in different conditions by means of a highly basic solution and a nearly neutral solution both containing ammonium salts. Samples have been calcined at different temperatures in order modify the number of defective sites. We observed that samples exchanged by means of a highly basic solution (pH > 10)1,2 and calcined at a relatively lower temperature (450 C) show the most interesting catalytic results. X-ray powder diffraction patterns of these samples show2 retention of the unit cell symmetry (orthorhombic cell) if compared to the dried sample. NH3-TPD confirms the low acidity of high silica zeolites, however a higher amount of desorbed ammonia is observed for the samples exchanged at higher pH and calcined at 450 C. Due to silanol nests the IR spectra of the same samples show the formation of Si\u2013NH2 bonds which are absent in the same material exchanged by other methods. Such sites seem to promote the high stability of the high silica zeolite catalysts also to the regeneration which is needed to remove the heavy carbonaceous compounds from the catalyst surface

del (3) (q13.11q21.1): descrizione di un nuovo caso

La delezione interstiziale della regione prossimale del braccio lungo del cromosoma 3 (q11-q21) \ue8 un\u2019alterazione cromosomica molto rara ed \ue8 stata descritta solo in 13 pazienti. Riportiamo il caso di un bambino di 8 mesi nato con parto eutocico da genitori sani non consanguinei. Il cariotipo da sangue periferico ha mostrato la presenza di un\u2019ampia delezione sul braccio lungo del cromosoma 3: 46,XY,del(3)(q12q21) confermata per mezzo di FISH. L\u2019Array-CGH ha evidenziato che la delezione \ue8 pari a 18,97 Mb e si estende da q13.11 a q21.1 consentendo di definire in modo pi\uf9 preciso il cariotipo: 46,XY,del(3)(q13.11q21.1) Il cariotipo normale di entrambi i genitori ha confermato l\u2019insorgenza de novo della delezione. Il bambino presenta tratti dismorfici del volto (fronte ampia, epicanto bilaterale, radice nasale a sella, ipoplasia della parte mediana del volto, padiglioni auricolari a basso impianto), ipotono assiale con ritardo moderato nell\u2019acquisizione delle tappe di sviluppo, plagiocefalia, ipoplasia del corpo calloso, assottigliamento della sostanza bianca in sede peritrigonale bilaterale, anomala conformazione del tronco encefalico per lieve ipoplasia del ponte, tendenza all\u2019inversione della fisiologica lordosi cervicale, criptorchidismo sinistro ed ernia inguinale sinistra Per quanto riguarda la correlazione genotipo-fenotipo il gene CBLB (3q13.11) sembra responsabile delle alterazioni craniofacciali, il gene BOC (3q13.2) dell\u2019ipotonia muscolare, il gene DRD3 (3q13.3) del ritardo dello sviluppo. La comparazione delle caratteristiche cliniche del nostro paziente con quelle dei pazienti descritti in letteratura conferma che la delezione della regione prossimale del braccio lungo del cromosoma 3 determina un fenotipo eterogeneo che comprende dismorfismi a carico del volto, ipotonia, ritardo di sviluppo, difetti cardiaci, anomalie celebrali, anomalie scheletriche e genitourinarie. L\u2019espressivit\ue0 variabile del fenotipo potrebbe essere dovuta all\u2019ampiezza della delezione variabile per differenti punti di rottura e alla presenza in questa regione di geni sensibili al dosaggio e o allo smascheramento di alleli recessivi, che a seguito della delezione si troverebbero in una condizione di emizigosi

3D morphometric evaluation of the face in Marfan syndrome: a better definition of dysmorphic features

Marfan syndrome (MFS) is a rare genetic disorder of connective tissue caused by mutations in the FBN1 gene, which result in alterations of fibrillin-1 and dysregulation of TGF-b bioavailability in the extracellular matrix. MFS is a clinical diagnosis. It is crucial to prevent acute aortic dissection; nevertheless it is difficult, due to the high degree of clinical variability of the disease. A quantitative definition of craniofacial abnormalities associated with MFS is not available and they are usually evaluated through a qualitative impression. The study aimed to better characterize the facial phenotype associated with MFS, identifying new morphometric features useful for the diagnosis of the disease. 3D facial images of 61 Italian subjects diagnosed with MFS, aged 16-64 years (21 males, mean ± SD age 38 ± 15 years; 40 females, mean ± SD age 41 ± 13 years), and divided in 6 non-overlapping age groups, were obtained by stereophotogrammetry [1]. From the coordinates of 50 soft-tissue facial landmarks, linear distances and angles were measured; z score values were calculated comparing patients with healthy Italian reference subjects (400 males, 379 females), matched for gender and age group. Statistical comparisons were performed by Student’s t test. All subjects with MFS showed a greater facial divergence (

The new fragment in-flight separator at INFN-LNS

An upgrade project of the Superconducting Cyclotron has been underway at INFN-LNS since 2019. One of the goals of this project is to deliver RIBs (Radioactive Ion Beams) of high intensity. To reach this aim, a dedicated facility consisting of a new fragment separator FRAISE (FRAgment In-flight SEparator) is ongoing, exploiting primary beams with a power up to approximate to 2-3 kW. The high intensity achievable with FRAISE requires the use of suitable diagnostics and tagging systems, able to operate also in a strong radioactive environment. In this framework, an R&D program has been started to develop the FRAISE facility, the diagnostics system and the tagging device; the latter will be especially useful in the CHIMERA multidetector beam line. The present contribution discusses the status of the R&D program, with particular focus on the RIBs available thanks to the use of FRAISE

Evidence of dynamical dipole excitation in the fusion-evaporation of the 40Ca +152Sm heavy system

The excitation of the dynamical dipole mode along the fusion path was investigated for the first time in the formation of a heavy compound nucleus in the A ∼ 190 mass region. The compound nucleus was formed at identical conditions of excitation energy and spin from two entrance channels: the charge-asymmetric 40 Ca + 152 Sm and the nearly charge-symmetric 48 Ca + 144 Sm at E lab = 11 and 10.1 MeV / nucleon, respectively. High-energy γ rays and light charged particles were measured in coincidence with evaporation residues by means of the MEDEA multidetector array (Laboratori Nazionali del Sud, Italy) coupled to four parallel plate avalanche counters. The charged particle multiplicity spectra and angular distributions were used to pin down the average excitation energy, the average mass, and the average charge of the compound nucleus. The γ -ray multiplicity spectrum and angular distribution related to the nearly charge-symmetric channel were employed to obtain new data on the giant dipole resonance in the compound nucleus. The dynamical dipole mode excitation in the charge-asymmetric channel was evidenced, in a model-independent way, by comparing the γ -ray multiplicity spectra and angular distributions of the two entrance channels with each other. Calculations of the dynamical dipole mode in the 40 Ca + 152 Sm channel, based on a collective bremsstrahlung analysis of the reaction dynamics, are presented. Possible interesting implications in the superheavy-element quest are discussed

Dynamical signals in fragmentation reactions : Time scale determination from three fragments correlations by using the 4 [Pi] Chimera multidetector

For fragments emitted in the reactions 124Sn + 64Ni and 112Sn + 58Ni at 35 AMeV, isotopic composition and velocity correlations have been studied as a function of the centrality of the collision, using the 4 Chimera multidetector. We have investigated the time scale for fragments formation, in order to distinguish between prompt dynamical and sequential statistical emission. Promptly emitted light fragments (Z ≤9) produced in the mid-rapidity domain are characterised by larger N/Z ratio and stronger angular anisotropies than those produced in sequential statistical emission. Results are compared with stochastic BNV code simulations obtained for primary fragments. Valuable information on the symmetry term of the nuclear equation of state at sub-saturation densities are obtained

Isoscaling in neck fragmentation

Production of intermediate mass fragments (IMF) has been studied in semi-peripheral 124Sn (35AMeV) + 64Ni and 112Sn (35AMeV) + 58Ni reactions. Our recently proposed new method of an analysis of the neck- like fragmentation processes that provides information on the IMFs time equence and time scale is reviewed. Isotopic analysis of so characterized IMFs gives evidence for neutron enrichment of mid-velocity fragments. A clear isoscaling behavior is found despite the short emission time scale. Evolution of the isoscaling parameters from semi-peripheral to central collisions is discussed

Investigation of the dynamical dipole mode in the 192Pb mass region

The dynamical dipole mode was investigated in the mass region of the 192Pb compound nucleus, by using the 40Ca + 152Sm and 48Ca + 144Sm reactions at E lab=11 and 10.1 MeV/nucleon, respectively. Both fusion-evaporation and fission events were studied simultaneously for the first time. Our results show that the dynamical dipole mode survives in reactions involving heavier nuclei than those studied previously, however, its yield is lower than that expected within BNV calculations

Measurement of the non-prompt D-meson fraction as a function of multiplicity in proton-proton collisions at s \sqrt{s} = 13 TeV

The fractions of non-prompt (i.e. originating from beauty-hadron decays) D0 and D+ mesons with respect to the inclusive yield are measured as a function of the charged-particle multiplicity in proton-proton collisions at a centre-of-mass energy of √s = 13 TeV with the ALICE detector at the LHC. The results are reported in intervals of transverse momentum (pT) and integrated in the range 1 < pT < 24 GeV/c. The fraction of non-prompt D0 and D+ mesons is found to increase slightly as a function of pT in all the measured multiplicity intervals, while no significant dependence on the charged- particle multiplicity is observed. In order to investigate the production and hadronisation mechanisms of charm and beauty quarks, the results are compared to PYTHIA 8 as well as EPOS 3 and EPOS 4 Monte Carlo simulations, and to calculations based on the colour glass condensate including three-pomeron fusion