20 research outputs found
Il banchetto dei giusti nel mondo a venire. Per la storia di un motivo ebraico
No full textThe article studies the reception of the topical reference to a banquet for the righteous in the world to come, attested vastly in the Rabbinical literature and being source of puzzlement for the philosophers and an exegetical challenge for the Kabbalists. In particular, its mention and interpretation in the work of Francesco Zorzi, In Scripturam Sacram Problemata (1526) is studied in detail, pointing to its sources and to the peculiar interpretation offered by the Christian Kabbalist of the Renaiccance
A new application of SIMS to the analysis of nitrogen in mica minerals: tobelite.
No full textMuscovite, KAl2[AlSi3O10](OH)2, is a common rock-forming mineral in igneous and
metamorphic-rocks, sediments, hydrothermal alteration and ore deposits. The site between two
adjacent T-O-T (tetrahedral-octahedral-tetrahedral) layers is shared between K and NH4 in any
proportion leading to the building of the “ammonium micas”. Mica with: (i) NH4>K,
□ (vacancy); (ii) Si ≥ 3 apfu (atoms per formula unit); (iii) layer charge (T-O-T) less than one,
is named tobelite [Brigatti M F and Guggenheim S 2002 Rev. Mineral. Geochem. 46 1-97].
The NH4-analog of muscovite, i.e., tobelite, has been predominantly associated to two distinct
geological settings: a) diagenetic to low grade metamorphic shales from meta- anthracite and
anthracite coal fields; b) hydrothermal areas alteration [Ruiz Cruz M D and Sanz de Galdeano
C 2010 Clays Clay Miner. 58 558-572].
In this work three crystals labelled Tob_M2, Tob_M3, Tob_3 were investigated by electron
probe microanalysis (EPMA) in terms of major constituents, and in terms of nitrogen by
secondary ion mass spectrometry (SIMS) in order to gain information on the presence and
amount of NH4. Nitrogen was detected as secondary positive ions by means of a Cameca IMS
4f ion microprobe installed at CNR-IGG, Pavia. SIMS analysis on 14N+ was performed with
16O- primary beam at a mass resolution (M/ΔM) of ~ 1250 required to discriminate the 28Si2+
and 12CH2
+ interferences at the nominal mass number 14 (a.m.u.).
In spite of the severe inhomogeneity of nitrogen in each crystal, the SIMS data put Tob_M2 as
the N-richest crystal of the set. The crystal, analyzed at different spots, is characterized by an
ion signal in the range 399 - 560 (c/s). For Tob_M3 the 14N+ average ion signal is 91 (c/s). In
Tob_3 the N content is likely the lowest in the sample set with an average count rate of
61 (c/s).
The lack of calibration standards did not allow so far to obtain quantitative results for N at the
ion microprobe. Nevertheless, our SIMS data agree qualitatively with constraints derived from
EPMA and charge-balance crystal chemical considerations, and point out that the ion probe is a
valuable tool for the investigation of N in mica minerals
XRD, micro-XANES, EMPA and SIMS investigation on phlogopite single crystals from Mt. Vulture (Italy)
No full text
Persistance of regenerative myogenesis in spite of down-regulation of activity-dependent genes in long-term denervated rat muscle.
No full textContrary to general expectation, in humans we have recently shown that after complete Conus Cauda lesion, the lower motoneuron denervated myofibers may survive several years. In adult rats, the sciatectomized muscle progresses in 4-6 months from severe atrophy to a dystrophic stage and undergoes a dramatic weight loss; during this process, myofiber death/regeneration processes maintain a decreasing population of very small, but vital myofibers. At the same time, in vitro electrophysiological recordings show that denervated fibers can maintain membrane excitability longer than they can retain contractile properties. A certain level of myofiber regeneration seems to have a role in the process, with the early re-expression of embryonic subunits of integrins and acetylcholine receptor subunits. In the present work, using the reliable Real-Time quantitative PCR, we confirm the long-lasting occurrence of myoblast proliferation-dependent events and their focal nature. In fact, we show here that in sciatectomized muscle the expression of 12 selected genes was differentially regulated at 3- and 9-month denervation. At both time points, indexes of muscle activity/inactivity and tissue re-modeling (proteolysis, energy usage, angiogenic factors) were down-regulated, while indexes of regenerative myogenesis (Myogenin, MyoD, Mrf4, MHCemb) were up-regulated. Immunohistochemistry with anti-MHCemb and anti-N-CAM monoclonal antibodies show that such regeneration events were focally distributed. We conclude that myofiber regeneration is a non-compensatory mechanism, which prolongs the chance of re-innervation during long lasting denervation. It may also contribute to muscle recovery in paraplegic patients, even when rehabilitation strategies based on Functional Electrical Stimulation (FES) start late after Spinal Cord Injury (SCI)
An in situ HT-HP single crystal X-ray diffraction study of armstrongite, a microporous zirconium silicate
No full textArmstrongite, CaZr[Si6O15]·2H2O, is a natural “zeolite-like” Zr-silicate with a heteropolyhedral framework consisting of SiO4 tetrahedra and ZrO6 octahedra that form cavities occupied by Ca-exchangeable cations (Mesto et al., 2014). The behavior at non ambient conditions of armstrongite from Khan Bogdo deposit (Gobi, Mongolia) was studied by in-situ High Temperature Single Crystal X-ray Diffraction (HT SCXRD), both in air and under dry conditions up to 500°C and 375 °C respectively, and by in-situ High Pressure Single Crystal X-ray Diffraction (HP SCXRD) using synchrotron X-ray diffraction data (collected up to 8.01 GPa), a diamond anvil cell and the mix methanol:ethanol:water as hydrostatic pressure-transmitting fluid.
On heating an abrupt discontinuity in the trend of the cell parameters and unit-cell volume occurs at T = 275°C in dry condition and at T = 450°C in air. The cell volume decreased by ~7.5%, compared to that measured at RT, and is compatible with the loss of the two water molecules. The dehydrated phase (solved and refined at 275°C only under dry conditions) exhibits the same space group (C2/m) as RT armstrongite, significantly shortened a and b cell dimensions, increased β angle, and smaller unit-cell volume (a = 13.406(3), b = 13.752(3), c = 7.811(2) Å, β = 110.22(3)°, V = 1351.3(5) Å3) with respect to the hydrated phase (a = 14.0135(7), b = 14.1234(6), c = 7.8388(4) Å, β = 109.401(4)°, V = 1463.4(1) Å3) at RT. The process is also accompanied by the distortion of the cavities as a consequence of Ca splitting and positional disorder of tetrahedral framework oxygens. The dehydration/rehydration process of armstrongite is completely reversible as also found from previous HT XRPD investigation (Schingaro et al., 2018).
HP SCXRD data show a first-order phase transition between 4.01(5) and 5.07(5) GPa. In the high-pressure polymorph, the unit-cell volume triplicates. The bulk compression of armstrongite is mainly accommodated through the tilting of both SiO4 tetrahedra and ZrO6 octahedra around the shared oxygen hinges. The high-P polymorph of armstrongite is found to be stiffer (KV0 increase of ~ 66%), and a remarkable change of the elastic anisotropic scheme occurs. No evidence of crystal-fluid interaction, with a selective sorption of molecules of the pressure-transmitting fluid through the cavities, was observed.
Mesto, E., Kaneva, E., Schingaro, E., Vladykin, N., Lacalamita, M. & Scordari, F. (2014): Armstrongite from Khan
Bogdo (Mongolia): crystal structure determination and implications for zeolite-like cation exchange properties. Am.
Mineral., 99, 2424-2432.
Schingaro, E., Lacalamita, M., Mesto, E. & Della Ventura, G. (2018): Thermal stability and dehydration of armstrongite,
a microporous zirconium silicate. Micropor. Mesopor. Mat., in press
Structure, composition and origin of yangzhumingite and phlogopite from the Kvaløya lamproite (North Norway)
No full textThis study reports a petrographic and crystal chemical analysis of three types of micas (yangzhumingite, light brown phlogopite and dark brown phlogopite) found in a lamproitic dyke at the Kvaløya Island (North Norway). The study was carried out integrating different analytical techniques: electron microprobe, single crystal X-ray diffraction, inductively coupled plasma mass spectrometry, Mössbauer and micro-Fourier Transform infrared spectroscopy. Kvaløya yangzhumingite (second occurrence in nature) was characterized for the first time in detail via single crystal X-ray diffraction.
The different mica types are distinguishable on the basis of the VIFe and Mg versus Si content. Yangzhumingite composition is intermediate between those of KMg2.75(Si3.5Al0.5)O10F2 and KMg2.50Si4O10F2 synthetic compounds reported in the literature. Light and possibly dark brown phlogopite is a Mg-rich fluorotetraferriphlogopite, the latter having a greater Fe content. The infrared spectra of yangzhumingite and the light brown phlogopite show the occurrence of OH- absorption bands respectively at: ~ 3586 cm- 1 which correlates well with the measured F content; 3707 cm- 1 and 3686 cm- 1 assigned mainly to 3Mg2 +-K+-OH- (phlogopitic) environment.
Structural analyses, performed only on yangzhumingite and light brown phlogopite show that both samples are 1M polytypes with the expected space group C2/m. Crystal chemical details are compatible with the following major substitution mechanisms: 2XIIK+ + VI[] ↔ 2XII[] + VIR2 + (where R2 + = Mg, Fe), OH- ↔ F- for yangzhumingite and 2VIR2 + ↔ VITi4 + + VI[] (Ti-vacancy), OH- ↔ F- for light brown phlogopite.
All three types of micas formed at relatively constant low pressure, but over a large temperature range in equilibrium with a grain boundary fluid that underwent significant changes in composition during reaction progress. Light brown phlogopite cores and dark brown phlogopite rims formed during crystallization from the lamproitic magma, while yangzhumingite formed as a result of reactions between the already formed phlogopite and the highly reactive fluid that was derived from the volatile-rich lamproite magma
The coordination chemistry of functionalised poly(pyrazol-1-yl)borate ligands and the photophysical properties of cyanide-bridged d-f hybrids
No full textThe content of this thesis is concerned with two distinctly independent areas of
research: (i) the synthesis and study of new poly(pyrazol-1-yl)borate ligands and
their metal complexes; (ii) crystallographic and photophysical studies of new d-f
hybrid complexes.
Chapter One is divided into three parts: Part one gives a general introduction
to poly(pyrazol-1-yl)borate chemistry along with a concise and up-to-date review of
those ligands containing substituents in the C3 position of the pyrazolyl ring; part two
provides a brief introduction into the physical properties of lanthanide(III) metal
ions, as well as describing the practical applications of their individual spectroscopic
properties; and part three contains a brief review on the structural chemistry of
cyanide-bridged coordination polymers.
Chapter Two describes the syntheses of four new scorpionates: dihydrobis[3-(4-pyridyl)pyrazol-1-yl]borate (Bp4py); dihydro-bis[3-(3-pyridyl)pyrazol-1-
yl]borate (Bp3py); hydro-tris[3-(4-pyridyl)pyrazol-1-yl]borate (Tp4py) and hydrotris[3-(3-pyridyl)pyrazol-1-yl]borate (Tp3py). A series of X-ray crystallographic
studies reveals a range of mononuclear, dinuclear and polymeric coordination
complexes with various metal ions.
Chapter Three describes a range of structural and photophysical studies on
lanthanide(III) complexes of poly(pyrazol-1-yl)borate ligands. New mixed-ligand
lanthanide(III) complexes with various combinations of the anionic ligands Tp2py
,
Bp2py and dibenzoylmethane (dbm) were prepared and structurally characterised.
Photophysical studies on the isostructual series [Ln(Bp2py)(dbm)2] (Ln = Pr, Nd, Er,
Yb) show characteristic near-IR luminescence from the lanthanide ion. Near-IR
luminescence was also demonstrated from the complexes [Ln(Bp2py)
2(NO3)] and
[Ln(Tp2py)(NO3)
2] (Ln = Pr, Er), upon suitable excitation of the ligand
chromophores.
Chapter Four describes the structural and photophysical properties of new
cyanide-bridged d-f coordination polymers. Structural and photophysical studies are
presented for a series of Ru-Ln complexes based on the [Ru(bipy)(CN)4]
2- donor unit
connected to a Ln(III) energy-acceptor via cyanide bridges (where bipy is 2,2’-
bipyridine and Ln = Pr, Nd, Er, Yb). Structural and photophysical studies were also
performed on [Cr(CN)6][Ln(DMF)4(H2
O)2] complexes, in which the lanthanide ion
(Ln = Nd, Yb) acts as the energy acceptor from the hexacyanochromate
chromophore. The structures of [Cr(CN)6][Ln(H2
O)2] (Ln = Gd, Yb) and
K2[Ru(phen)(CN)4] (where phen = 1,10-phenanthroline) are also presented.
Chapter Five gives a brief review of the field of X-Ray Crystallography with
analysis of the history and theory of the technique, as well as an overview of its
practical aspects used in this work. A few crystal structures solved by the author,
and independent of the topics in this thesis, are also reported
Implementing fencing as adapted physical activity in non-metastatic breast cancer patients: design and early rehabilitation strategy of the FENICE study protocol
No full textbackground Improving prognosis of BC patients has drawn the attention of health care professionals on disease related long-term side effects and on the multiple treatments BC patients must undergo. despite advances in procedures, surgery still has multiple detrimental effects, including pain, edema, and limited mobility. For this reason, fostering adapted physical activity (APA) and healthy lifestyle (including a balanced diet and weight management) should become an everyday purpose of healthcare professionals. Fencing may be a well-suited activity to counteract fatigue, pain, and limited arm mobility. method and analysis The FENICE study is a mono-center, randomized clinical trial targeting women with BC stages I-III within four weeks from BC surgery. participants in the control arm will receive the usual recommendations based on the good clinical practice guidelines. In the study arm, participants will be treated with the usual clinical and therapeutic recommendations together with APA and correct lifestyle suggestions. objective the primary objective of the study is to compare whether implementation of APA and healthy lifestyle in BC patient after surgery will result in an overall improvement of physical and mental status. conclusion fencing and its early application in postoperative period may represent a feasible strategy to be implemented in the rehabilitation journey of BC patients. ethics and dissemination the study protocol FENICE has been approved by an italian ethics committee on May 2023 (R.S 100.23 5th May 2023)
