1,887 research outputs found
Pharmacological and neurobiological studies on Neuropeptide S and its receptor
No full textNeuropeptide S (NPS) is the last neuropeptide identified via reverse pharmacology techniques. NPS
selectively binds and activates a previously orphan GPCR, now named NPSR, producing intracellular Ca2+
mobilization and stimulation of cAMP levels. Biological functions modulated by the NPS/NPSR system
include anxiety, arousal, locomotion, food intake, learning and memory, pain and drug addiction. In our
laboratories we provided further evidence that NPS injected supraspinally in mice acts as a stimulatory
anxiolytic. In fact, in the mouse righting reflex (RR) test, NPS (0.01- 1 nmol, i.c.v.) was able to reduce in a
dose dependent manner the percent of animals losing the RR in response to diazepam (15mg/kg, i.p.) and
their sleep time. Furthermore, NPS in the same range of doses caused a significant increase in locomotor
activity (LA) in mice. These effects were associated with a clear anxiolytic-like action elicited by NPS in the
mouse elevated plus maze (EPM) test, open field (OF) test and stress-induced hyperthermia (SIH) assay.
Thus NPS evokes an unique pattern of behavioural effects: stimulation associated with anxiolysis. To deeply
investigate the biological roles played by the NPS/NPSR system the development of pharmacological (i.e.
selective NPSR ligands, particularly antagonists) and genetic (i.e. receptor knockout animals) tools are
needed. In collaboration with the medicinal chemistry group of the University of Ferrara, we performed a
series of classical structure-activity (SAR) studies on NPS sequence. Specifically, NPS positions 2, 3, 4 and
5 were investigated in details, since they were demonstrated to be crucial for NPS bioactivity. Studies
focussed on NPS position 5 led to the identification and the in vitro and in vivo pharmacological
characterization of the first generation of NPSR peptide antagonists. In vitro, in HEK293 cells stably
expressing the mouse NPSR, [D-Cys(tBu)5]NPS up to 100 μM did not stimulate Ca2+ mobilization but was
able to counteract in a competitive manner the stimulatory action of NPS (pA2: 6.44). In vivo, in the RR test,
[D-Cys(tBu)5]NPS at 10 nmol was inactive per se but dose dependently antagonized the arousal-promoting
action of NPS 0.1 nmol. [D-Val5]NPS acted in vitro as a pure NPSR antagonist, with a pKB of 6.54 in
inhibition experiments. In vivo, in LA test, [D-Val5]NPS at 10 nmol completely blocked the stimulatory
effect evoked by NPS. In a further medicinal chemistry study, the potent NPSR antagonist [tBu-D-Gly5]NPS
was identified. In vitro, [tBu-D-Gly5]NPS did not stimulate calcium mobilization but blocked the stimulant
action of NPS with a pKB of 7.06 7. In vivo, in RR assay, [tBu-D-Gly5]NPS (0.1-10 nmol, i.c.v.) was inactive
per se but dose dependently antagonized the arousal-promoting action of NPS 0.1 nmol. Similarly in the LA
assay [tBu-D-Gly5]NPS (0.1-10 nmol, i.c.v.) was inactive per se but was able to counteract the stimulatory
effect evoked by 0.1 nmol NPS in a dose dependent manner. SHA 68 has been previously identified as the
first non peptide NPSR antagonist. In our laboratories we further assessed the pharmacological profile of
SHA 68 in vitro and in vivo. In vitro SHA 68 was inactive per se up to 10 μM while it antagonized NPSstimulated
Ca2+ mobilization in a competitive manner showing a pA2 value of 8.06. In vivo, in the mouse RR
assay, SHA68 50 mg/kg i.p. fully prevented the arousal promoting action of NPS 0.1 nmol. In LA
experiments, SHA 68 50 mg/kg i.p. was able to partially counteract the stimulant effects elicited by NPS 0.1
nmol. Instead, the anxiolytic-like effects of NPS 0.1 nmol in mouse OF test were slightly reduced by SHA
68. Collectively these data demonstrated the exclusive involvement of NPSR in the arousal promoting and
locomotor stimulant effects of NPS. Finally, we backcrossed on the CD-1 strain the NPSR knockout mice
originally generated on the 129Sv/Ev genetic background. A first phenotype analysis revealed no locomotor
differences between NPSR(+/+) and NPSR(-/-) mice, with the exception of rearing behaviour that was
reduced in knockout animals. Furthermore, the behaviour of NPSR(+/+) and NPSR(-/-) mice in the EPM, OF
and SIH tests is superimposable. Similarly no differences were detected in the novel object recognition,
forced swimming, RR and formalin assays. However, the stimulant actions of 1 nmol NPS in RR and in LA
test could be detected in NPSR(+/+) but not in NPSR(-/-) mice. Collectively these data demonstrated that
endogenous NPS/NPSR system does not play a role in the control of locomotion, anxiety, depression and
memory, at least under the present experimental conditions. These results demonstrated that the NPS
stimulant effects are selectively due to NPSR activation, corroborating the findings obtained with NPSR
antagonists. In conclusion, the research activity performed during the PhD program led to the identification
of the first generation of NPSR peptide antagonists. The use of these research tools in parallel with knockout
studies generated converging evidence on the biological effects induced by the selective activation of NPSR
The pixel module for the Inner Tracking System upgrade of ALICE at LHC
No full textThe ALICE (A Large Ion Collider Experiment) detector at the CERN LHC collider was designed to address
the physics of strongly interacting matter, and in particular the properties of the Quark-Gluon
Plasma (QGP) using proton-proton, proton-nucleus, and nucleus-nucleus collisions. Even if with
this physics goal a lot of important results were already reached, there are still several fundamental
measurements to be finalized, like high precision measurements of rare probes (D, B mesons and
Lambda barions decays) over a broad range of transverse momenta. In order to achieve these new
results, a wide upgrade plan was approved that combined with a significant increase of luminosity
will enhance the ALICE physics capabilities enormously.
The ALICE Inner Tracking System (ITS) upgrade is one of the major improvements of the experimental
set-up that will take place in 2019-2020 where the whole ITS sub-detector will be replaced with
a new one realized using a innovative CMOS Monolithic Active Pixel silicon Sensor (MAPS), called
ALPIDE. This new upgraded ITS will be realized using more than twenty-four thousand ALPIDE
chips organized in seven different cylindrical layers surrounding the ALICE interaction point along
the beam-line, for a total surface of about ten square meters. The main features of the future ALICE
ITS are a low material budget, high granularity and low power consumption. All these peculiar capabilities
will allow for full reconstruction of rare heavy flavor decays and the achievement of the
physics goals.
In this talk after a description of new ALIPIDE pixel chip and the whole ITS upgrade project, will be
presented the construction procedure of the basic building block of the detector, namely the module,
and the laboratory characterization of this element
Effect of Low-Temperature Preservation in Optisol-GS on Preloaded, Endothelium-Out DMEK Grafts
No full textThe aim of the study was to assess different temperature ranges for the preservation of pre-loaded Descemet Membrane Endothelial Keratoplasty (DMEK) grafts in the DMEK RAPID Mini device. Methods: Three groups of 15 DMEK grafts (five per group) were pre-loaded in the DMEK RAPID Mini and preserved in Optisol-GS for 72 h at different temperatures: group A at >8 °C, group B between 2–8 °C and group C at 0.05). Endothelial cell density variation was 5.51%, 3.06% and 2.82% in groups A, B and C, respectively (p = 0.19). Total Endothelial Cell Loss (ECL) was 4.37%, 5.32% and 7.84% in groups A, B and C, respectively (p = 0.39). Endothelial cell morphology was comparable in all three groups. Conclusions: In the DMEK RAPID Mini, low temperatures (<2 °C) may affect the quality of pre-loaded grafts, inducing a higher ECL after 72 h of preservation, although no significant differences among groups could be proved. Our data would suggest maintaining grafts loaded in the DMEK RAPID Mini at temperatures between 2–8 °C for appropriate preservation
Combinatorics of Classical Unitary Invariant Ensembles and Integrable Systems
No full textThe first part of this thesis is devoted to the combinatorics, geometry, and effective computation of correlators of unitary invariant ensembles of random hermitian matrices with classical potentials. The main results are the subject of the publications [7, 8] with my supervisors T.~Grava and G.~Ruzza, and are summarized as follows.
We provide generating functions for correlators of general Hermitian matrix models; formulae of this sort have already appeared in the literature [1, 5], we rederive them here with different methods which lend themselves to further generalizations. Such formulae are not recursive in the genus and hence particularly effective. Moreover, these formulae express the correlators of classical unitary ensembles as linear combinations of products of discrete hypergeometric polynomials; this generalizes relations to discrete orthogonal polynomials for the one-point correlators \langle \tr M^k \rangle of the classical ensembles recently discovered by Cunden et al. [3].
Hence, we turn our attention on the combinatorial interpretation of correlators for the Laguerre and Jacobi ensembles. We prove that the coefficients in the topological expansion of Jacobi correlators are multiparametric single Hurwitz numbers involving combinations of triple monotone Hurwitz numbers. Via a simple limit, this reproduces formulae of [2] on the Laguerre ensemble. This completes the combinatorial interpretation of correlators of unitary ensembles with classical potential.
Combining results of Dubrovin et al. [4], and of Norbury [10] connecting integrable systems with enumerative geometry, we obtain ELSV-like formulae linking the multiparametric single Hurwitz numbers of LUE and JUE respectively to cubic Hodge integrals and -GW invariants.
In the second part of the thesis we analyse various integrable dynamical systems from a probabilistic point of view. Specifically, we study the spectrum of their random Lax Matrix equipped with the associated Gibbs Measure, in the spirit of [9, 11]. This is the content of the preprint [6], in collaboration with T.~Grava, G.~Gubbiotti and G.~Mazzuca.
We explicitly compute the density of states for the exponential Toda lattice and the Volterra lattice showing they are connected to the Laguerre -ensemble at high temperatures and the -antisymmetric Gaussian ensemble at high temperatures respectively. For generalizations of these system we derive numerically their density of states and compute their ground states.
[1] M. Bertola, B. Dubrovin, and D. Yang, Correlation functions of the KdV hierarchy and applications to intersection numbers over Mg,n, Phys. D, 327 (2016), pp. 30–57.
[2] F. D. Cunden, A. Dahlqvist, and N. O’Connell, Integer moments of complex Wishart matrices and Hurwitz numbers, Ann. Inst. Henri Poincar ́e D, 8 (2021), pp. 243–268.
[3] F. D. Cunden, F. Mezzadri, N. O’Connell, and N. Simm, Moments of random matrices and hypergeometric orthogonal polynomials, Comm. Math. Phys, 369 (2019), pp. 1091–1145.
[4] B. Dubrovin, S. Q. Liu, D. Yang, and Y. Zhang, Hodge-GUE correspondence and the discrete KdV equation, Comm. Math. Phys, 379 (2020), pp. 461–490.
[5] B. Eynard, T. Kimura, and S. Ribault, Random matrices, arXiv preprint arXiv:1510.04430, (2015).
[6] M. Gisonni, T. Grava, G. Gubbiotti, and G. Mazzuca, Discrete integrable systems and random Lax matrices, arXiv preprint arXiv:2206.15371, (2022).
[7] M. Gisonni, T. Grava, and G. Ruzza, Laguerre ensemble: Correlators, Hurwitz numbers and Hodge integrals, Ann. Henri Poincar ́e, 21 (2020), pp. 3285–3339.
[8] M. Gisonni, T. Grava, and G. Ruzza, Jacobi ensemble, Hurwitz numbers and Wilson polynomials, Lett. Math. Phys., 111 (2021), pp. 1–38.
[9] T. Grava and G. Mazzuca, Generalized gibbs ensemble of the Ablowitz-Ladik lattice, Circular β-ensemble and double confluent Heun equation, arXiv preprint: 2107.02303, (2021).
[10] P. Norbury, Gromov-Witten invariants of P1 coupled to a KdV tau function, Adv. Math., 399 (2022), p. 108227.
[11] H. Spohn, Generalized Gibbs ensembles of the classical Toda chain, J. Stat. Phys., 180 (2020), pp. 4–2
Measurement of the ratios of branching fractions B (B-s(0)-> D-s(-) pi(+) pi(+) pi(-))/B(B-0 -> D- pi(+) pi(+) pi(-)) and B(B-s(0) -> D-s(-) pi(+))/B(B-0 -> D- pi(+))
No full textUsing 355 pb(-1) of data collected by the CDF II detector in p (p) over bar at collisions at root s = 1.96 TeV at the Fermilab Tevatron, we study the fully reconstructed hadronic decays B-(s)(0) -> D-(s)(-)pi(+) and B-(s)(0) -> D-(s)(-) pi(+)pi(+)pi(-). We present the first measurement of the ratio of branching fractions B(B-s(0) -> D-s(-) pi(+)pi(+)pi(-))/B(B-0 -> D-s(-) pi(+)pi(+)pi(-)) = 1.05 +/- 0.10(stat) +/- 0.22(syst). We also update our measurement of B(B-s(0) -> D-s(-)pi(+))/B(B-0 -> D-pi(+)) to 1.13 +/- 0.08(stat) +/- 0.23(syst), improving the statistical uncertainty by more than a factor of 2. We find B(B-s(0) -> D-s(-)pi(+)) = [3.8 +/- 0.3(stat) +/- 1.3(syst)] x 10(-3) and B(B-s(0) -> D-s(-) pi(+)pi(+)pi(-)) = [8.4 +/- 0.8 (stat) +/- 3.2(syst)] x 10(-3)
Comparison of preservation and transportation protocols for preloaded Descemet membrane endothelial keratoplasty
No full textBackground/aims Descemet membrane endothelial keratoplasty (DMEK) preparation is technically demanding and is a limiting factor for uptake of this kind of surgery. Supply methods that simplify the procedure for surgeons are key to increasing uptake. This study compares two different shipping protocols for DMEK. Methods An 8.5 mm DMEK graft was punched, marked and loaded for transportation in two different conditions: (A) endothelium trifolded inwards in organ culture conditions (n=7) and (B) endothelium rolled outwards in hypothermic conditions (n=7). Tissues were shipped from Italy to the UK, then analysed for orientation, endothelial cell density, denuded areas, cell mortality, triple viability staining (Hoechst/ethidium homodimer/calcein AM (HEC)), immunolocalisation of ZO-1 and Na/K-ATPase proteins, visualisation of actin filaments using phalloidin and histological analysis using H&E on paraffin-embedded sections. Results All tissues clearly showed the mark used for graft orientation. After shipping in condition A, there was an increase in cell mortality of 8.1% and in denuded areas of 22.4%, whereas for condition B there was an increase in cell mortality of 14.2% and in denuded areas of 34.3% after shipping. HEC staining revealed areas of viable cells and apoptotic cells, with large denuded areas found in the periphery for condition B and within folds for condition A. Conclusions Prestripped preloaded DMEK grafts retained sufficient viable cells for transplantation, with condition A (endothelium-in) offering the advantage of greater flexibility of use due to a longer shelf-life. HEC analysis provides further detailed information as to the status of DMEK grafts and should be used in future similar studies
Culturing Discarded Peripheral Human Corneal Endothelial Cells From the Tissues Deemed for Preloaded DMEK Transplants
No full textPURPOSE: To investigate if the peripheral corneal endothelium that is discarded after the preparation of preloaded Descemet membrane endothelial keratoplasty (DMEK) grafts for transplantation could be successfully used for corneal endothelial cell culture. METHODS: Complete Descemet membrane-endothelial complex (11.00 mm) was peeled from research-grade tissues (n = 15). The periphery (2.75 mm) of clinical-grade tissues (n = 15) deemed for preloaded DMEK transplants was gently peeled and preserved for 48 hours in tissue culture media, followed by centrifugation at 1000 rpm for 5 minutes. After enzymatic digestion, the cells from each group were plated in 2 different wells of an 8-well chamber slide. Media were refreshed and the confluence rate was monitored every alternate day. Live/dead staining and the expression of ZO-1, Tag1A3, Tag2A12, and Ki-67 markers were used to assess the viability, morphology, tight-junctions, cell area, and number of proliferative cells. The Wilcoxon and Student's t test were applied, where P 0.05). All the antibodies were expressed in both groups at confluence. CONCLUSIONS: The discarded peripheral endothelial cells obtained after preparing a preloaded DMEK graft for clinical application has a huge reservoir of healthy endothelial cells having proliferative potential. Using these discarded tissue pieces from donor tissues will significantly increase the primary source of healthy donor endothelial cells for regenerative treatments, which are otherwise difficult to obtain
Increasing Donor Endothelial Cell Pool by Culturing Cells from Discarded Pieces of Human Donor Corneas for Regenerative Treatments
No full textPurpose. To investigate if the peripheral corneal endothelium that is usually discarded after a corneal transplant could be used for endothelial cell culture. Methods. Donor corneas (n = 19) with a mean age of 72 years, male: female ratio of 15: 4, and death-to-preservation time of 10 hours were assessed for endothelial cell density (ECD) and number of dead cells before isolation. Alizarin red staining (n = 3) was performed to check the morphology of cells in the center and periphery. Descemet's membrane-endothelial complex was peeled from the center (8.25 mm) and the periphery (2.75 mm) and plated in two different wells of an 8-well chamber slide with media refreshed every alternate day. The confluence rate was monitored by microscopy. Live/dead analysis was performed (n = 3) at confluence. Tag-2A12 as a monoclonal antibody against peroxiredoxin-6 (Prdx-6) (n = 4), ZO-1 (zonula occludens-1) as a tight junction protein (n = 4), and Ki-67 as a proliferative cell marker (n = 4) were used to characterize the cells at confluence. Results. At confluence, 8.25% average increase in the number of cells was observed from the central zone compared with 16.5% from the peripheral zone. Proliferation rate, hexagonality, Ki-67 positivity, and the cell area did not significantly differ between the groups (p>0.05). All the proteins corresponding to the biomarkers tested were expressed in both the groups. Conclusions. Although there are significantly fewer amounts of peripheral cells available after graft preparation for keratoplasty, these cells can still be used for endothelial cell culture due to their proliferative capability. The peripheral cells that are discarded after graft preparation can thus be utilized to increase the donor endothelial cell pool for regenerative treatments
Measurements of branching fraction ratios and CP-asymmetries in suppressed B^-→D(→K^+π^-)K- and B^-→D(→K^+π^-)π^- decays
No full text8 pages, 1 figure, submitted to Phys.Rev.D Rapid CommunicationsWe report the first reconstruction in hadron collisions of the suppressed decays B-→D(→K+π-)K- and B-→D(→K+π-)π-, sensitive to the Cabibbo-Kobayashi-Maskawa phase γ, using data from 7fb-1 of integrated luminosity collected by the CDF II detector at the Tevatron collider. We reconstruct a signal for the B-→D(→K+π-)K- suppressed mode with a significance of 3.2 standard deviations, and measure the ratios of the suppressed to favored branching fractions R(K)=[22.0±8.6(stat)±2.6(syst)]×10-3, R+(K)=[42.6±13.7(stat)±2.8(syst)]×10-3, R-(K)=[3.8±10.3(stat)±2.7(syst)]×10-3 as well as the direct CP-violating asymmetry A(K)=-0.82±0.44(stat)±0.09(syst) of this mode. Corresponding quantities for B-→D(→K+π-)π- decay are also reported
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