2,237 research outputs found
Bibliografia degli scritti di Clemente Mazzotta: 1971-2007
No full textIl saggio bibliografico ricostruisce l'intera produzione bibliografica di Clemente Mazzotta (1942-2006)
Customized Corneal Cross-Linking
No full textPersonalized accelerated crosslinking nomograms for the management of corneal ectasia were conceived after comparative analysis of demarcation lines and cell viability observed after customized accelerated epithelium-off crosslinking CXL treatments by spectral domain corneal OCT and scanning laser in vivo confocal microscopy matching all the clinical and instrumental data with mathematical models. Accelerated high-fluence Topography-guided CXL at 30 mW/cm2 UV-Power and Accelerated epithelium-off CXL with 9 and 15 mW/cm2 UV-A power with standardized Fluence of 5.4 J/cm2 were safe and effective demostrating a keratocytes apoptosis and demarcation line depth between 280 and 340 μm. The 30 mW ACXL showed a penetration with continuous and pulsed light between 150 and 200 μm. No endothelial damage was reported in any case. In vivo morphological studies demonstrated that Accelerated CXL allow a pachymetry-guided cutomization of CXL maintainig the standard Fluence of 5.4 J/cm2 and a total treatment time under 20 min. Moreover a pachymetry-guided ACXL nomogram (M nomogram) developed by Mazzotta C and Friedman M matching the physical and mathematical calculations with the miscostructural IVCM and OCT observations of demarcation lines depths allow an efficacous CXL management of primary and iatrogenic ectatic corneas also allowing a safe management of thin ectatic corneas
Collisional ionization equilibrium for optically thin plasmas. I. Updated recombination rate coefficients for bare through sodium-like ions
No full textReliably interpreting spectra from electron-ionized cosmic plasmas requires accurate ionization balance calculations for the plasma in question. However, much of the atomic data needed for these calculations have not been generated using modern theoretical methods and are often highly suspect. This translates directly into the reliability of the collisional ionization equilibrium (CIE) calculations. We make use of state-of-the-art calculations of dielectronic recombination (DR) rate coefficients for the hydrogenic through Na-like ions of all elements from He up to and including Zn. Where measurements exist, these published theoretical DR data agree with recent laboratory work to within typically 35% or better at the temperatures relevant for CIE. We also make use of state-of-the-art radiative recombination (RR) rate coefficient calculations for the bare through Na-like ions of all elements from H through to Zn. Here we present improved CIE calculations for temperatures from 104 to 109 K using our data and the recommended electron impact ionization data of Mazzotta et al. for elements up to and including Ni and Mazzotta for Cu and Zn. DR and RR data for ionization stages that have not been updated are also taken from these two additional sources. We compare our calculated fractional ionic abundances using these data with those presented by Mazzotta et al. for all elements from H to Ni. The differences in peak fractional abundance are up to 60%. We also compare with the fractional ionic abundances for Mg, Si, S, Ar, Ca, Fe, and Ni derived from the modern DR calculations of Gu for the H-like through Na-like ions, and the RR calculations of Gu for the bare through F-like ions. These results are in better agreement with our work, with differences in peak fractional abundance of less than 10%
Customized epithelial debridement for thin ectatic corneas undergoing corneal cross-linking: epithelial island cross-linking technique
No full textCosimo Mazzotta,1 Vincenzo Ramovecchi2 1Unità Operativa Complessa di Oculistica, Siena University Hospital, Siena, Italy; 2Unità Operativa Complessa di Oculistica, San Severino Marche Hospital, San Severino Marche, Italy Abstract: Thin corneas with a minimum corneal thickness less than 400 µm after epithelial removal represent a contraindication to standard epithelium-off cross-linking (CXL) treatment due to a significant endothelial cell density decrease and potentiality of permanent haze development. Preoperative swelling of the cornea with hypoosmolar riboflavin solutions broadens the spectrum of CXL indications to thin corneas. However the iatrogenic swelling effect might not be durable throughout the CXL procedure increasing the risk of postoperative complications. The transepithelial CXL technique proposed for thin corneas demonstrated poor clinical results and mid- to long-term keratoconus instability. The epithelial island CXL technique with customized pachymetry-guided epithelial debridement was evaluated by means of in vivo laser scanning confocal microscopy, corneal topography, and clinical examination in a 1-year follow-up, in order to assess if it may be considered an alternative surgical option for keratoconic patients with thin corneas undergoing corneal collagen CXL. According to our clinical and in-vivo micro-morphological results the technique results safe, and efficacious in stabilizing progressive keratoconus and may be considered a valid option in the treatment of thin ectatic corneas alone or in combination with hypoosmolar or dextran-free riboflavin solutions. Keywords: cross-linking, keratoconus, thin corneas, epithelial island, surgical techniqu
XPS characterization of polydopamine layers for improving surface biomolecule immobilization.
No full textPolydopamine (PDA) films have attracted a rapidly increasing research attention during the
last years due to its simple and rapid deposition under alkaline conditions in substrate
independent manner providing a universal coating for materials with different chemical and
physical properties [1]. Furthermore, this polymerized layer is enriched with functional
groups that enable immobilization of primary amine or thiol-based biomolecules via a simple
dipping process [2]. Although these fascinating aspects justify PDA wide and successful
application as a versatile coating for biomolecule immobilization, several aspects have not
been deeply investigated leaving some key details unclear and thus limiting PDA practical
applications. A number of approaches are commonly used for the growth of PDA [3], but the
effect of deposition conditions on film properties which in turn influence biomolecule
immobilization has not been systematically investigated yet.
In the present work, a detailed investigation by X-Ray Photoelectron Spectroscopy (XPS) of
PDA coatings deposited by different synthetic schemes (namely by autoxidation in air, under
a pure oxygen environment, in the presence of a strong oxidizing agent for different time
intervals (1, 3, 5, 8, 18, and 24 hours), and by electrochemical oxidation) is performed aimed
at investigating film thickness and chemical composition as a function of polymerization
conditions. Comparative spectroscopic analysis of PDA films revealed significant differences
in terms of deposition kinetics and abundance of chemical components and allowed
selection of synthesis conditions making PDA chemical structure richer in functionalities
mainly involved in conjugation of biomolecules. The high suitability of the selected PDA film
for bioconjugation was verified using a biomolecule conjugated to Horseradish Peroxidase or
to fluorophore, obtaining also an estimation of immobilization time-stability within 4 weeks
and a quantitative evaluation of immobilization extent. Moreover, further insight on
biomolecule anchoring was provided by the comparison of XPS data on PDA samples before
and after interaction with biomolecule [4].
[1] H. Lee, S.M. Dellatore, W.M. Miller, P.B. Messersmith, Science 318 (2007) 426–430.
[2] Y. Liu, K. Ai, L. Lu, Chem. Rev. 114 (2014) 5057–5115.
[3] H.W. Kim, B.D. McCloskey, T.H. Choi, C. Lee, M.J. Kim, B.D. Freeman, H.B. Park, ACS Appl.
Mater. Interfaces. 5 (2013) 233–238
[4] S. Rella, E. Mazzotta, A. Caroli, M. De Luca, C. Bucci, C. Malitesta, Appl. Surf. Sci. 447
(2018) 31–39
Progressive high-fluence epithelium-on accelerated corneal crosslinking: a novel corneal photodynamic therapy for early progressive keratoconus
No full textPurpose: To assess the preliminary clinical results of a new, progressively higher fluence-pulsed light Epi-On accelerated crosslinking nomogram (PFPL M Epi-On ACXL) in the treatment of progressive keratoconus (KC). Setting: Siena Crosslinking Center, Siena, Italy. Methods: A prospective pilot open, non-randomized interventional study, including 32 eyes of 32 young-adult patients over 26 years old with Stages I-III progressive KC undergoing PFPL M Epi-On ACXL, was conducted. Riboflavin loading was performed by using Paracel I 0.25% for 4 min and Paracel II 0.22% for 6 min. The Avedro KXL System (Glaukos-Avedro, Burlington, USA) was used for pulsed-light accelerated crosslinking (ACXL) at air room 21% oxygenation and 13 min of UV-A irradiation. The treatment fluence was set at 7.2 J/cm2, 8.6 J/cm2, and 10.0 J/cm2 in corneas with baseline pachymetry <420 μm (group 1: 8 eyes), ≥ 420 μm <460 μm (group 2, 11 eyes), and ≥ 460 μm (group 3, 13 eyes), respectively. Uncorrected distance visual acuity (UDVA), best-spectacle corrected visual acuity (BSCVA), Scheimpflug corneal tomography, and anterior segment OCT (AS-OCT) data were collected at baseline and postoperatively at 1, 3, and 6 months. Results: UDVA and BSCVA improved in all groups (P ≤ 0.05). Maximum keratometry values (K max) showed a significant decrease in the 10.0 J/cm2 group (Δ −1.68 D). The coma (HOAs) value improved significantly by the sixth month in all groups. OCT average demarcation lines were 211 ± 19 μm in group 1, 245 ± 23 μm in group 2, and 267 ± 21 μm in group 3. Conclusions: The preliminary results show that pachymetry-based PFPL M Epi-On ACXL nomogram stabilizes ectasia progression. Higher fluence Epi-On ACXL increases CXL penetration, with better functional outcomes in the absence of complications
Progressive high-fluence epithelium-on accelerated corneal crosslinking: a novel corneal photodynamic therapy for early progressive keratoconus
No full textPurpose: To assess the preliminary clinical results of a new, progressively higher
fluence-pulsed light Epi-On accelerated crosslinking nomogram (PFPL M Epi-On
ACXL) in the treatment of progressive keratoconus (KC).
Setting: Siena Crosslinking Center, Siena, Italy.
Methods: A prospective pilot open, non-randomized interventional study,
including 32 eyes of 32 young-adult patients over 26 years old with Stages I-
III progressive KC undergoing PFPL M Epi-On ACXL, was conducted. Riboflavin
loading was performed by using Paracel I 0.25% for 4min and Paracel II 0.22%
for 6min. The Avedro KXL System (Glaukos-Avedro, Burlington, USA) was used
for pulsed-light accelerated crosslinking (ACXL) at air room 21% oxygenation and
13min of UV-A irradiation. The treatment fluence was set at 7.2 J/cm2, 8.6 J/cm2,
and 10.0 J/cm2 in corneas with baseline pachymetry <420μm(group 1: 8 eyes),
420μm<460μm(group 2, 11 eyes), and 460μm(group 3, 13 eyes), respectively.
Uncorrected distance visual acuity (UDVA), best-spectacle corrected visual acuity
(BSCVA), Scheimpflug corneal tomography, and anterior segment OCT (AS-OCT)
data were collected at baseline and postoperatively at 1, 3, and 6 months.
Results:UDVA and BSCVA improved in all groups (P 0.05).Maximumkeratometry
values (K max) showed a significant decrease in the 10.0 J/cm2 group (1 −1.68
D). The coma (HOAs) value improved significantly by the sixthmonth in all groups.
OCT average demarcation lines were 211 ± 19μm in group 1, 245 ± 23μm in
group 2, and 267 ± 21μm in group 3.
Conclusions: The preliminary results show that pachymetry-based PFPL M
Epi-On ACXL nomogram stabilizes ectasia progression. Higher fluence Epi-On
ACXL increases CXL penetration, with better functional outcomes in the absence
of complications
Helium injection plasmas in FTU
No full textIn order to extend observations on the increase of electron density peaking in neon doped plasmas, already reported in FTU Mazzotta et al (2015 Nucl. Fusion 55 073027), some sessions have been performed by injecting helium gas on the L-mode plasmas during the last two experimental campaigns. This favorable scenario, which can fall within so called 'highly radiative' or 'plasma detachment' themes, is investigated in this paper. The description of the impact of the helium injection on plasma behavior, by varying plasma parameters and shape, is exposed, especially with respect to the density peaking and edge conditioning. It has been recorded that, not only the total amount of puffed helium, but also the injection rate intervenes in triggering a particle inflow. Finally, by using VUV spectroscopy measurements, a model to estimate concentrations of impurities is outlined here for the first time, in this way the helium amount is deduced
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