Papers by Lorenzo Torrisi
Physics of the Solid State, Jul 1, 2019
The laser irradiated GO foils were analysed successively by using different techniques such as 2.... more The laser irradiated GO foils were analysed successively by using different techniques such as 2.0 MeV alpha particle Rutherford backscattering spectrometry, X-ray photoemission spectroscopy and SEM-EDX. In particular, in vacuum irradiated graphene oxide samples the oxygen reduction has been observed with increment of the carbon content. In air irradiated GO samples an increase in oxygen has instead been highlighted. Furthermore thermal and chemical effects are induced by the photon irradiation. Results will be presented and discussed.
Polymers, Feb 25, 2023
Thin sheets of ultra-high molecular weight polyethylene (UHMWPE), both in pristine form and conta... more Thin sheets of ultra-high molecular weight polyethylene (UHMWPE), both in pristine form and containing carbon nanotubes (CNTs) or Fe 2 O 3 nanoparticles (NPs) at different concentrations, were prepared. The CNT and Fe 2 O 3 NP weight percentages used ranged from 0.01% to 1%. The presence of CNTs and Fe 2 O 3 NPs in UHMWPE was confirmed by transmission and scanning electron microscopy and by energy dispersive X-ray spectroscopy analysis (EDS). The effects of the embedded nanostructures on the UHMWPE samples were studied using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and UV-Vis absorption spectroscopy. The ATR-FTIR spectra show the characteristic features of the UHMWPE, CNTs, and Fe 2 O 3 . Concerning the optical properties, regardless of the type of embedded nanostructures, an increase in the optical absorption was observed. The allowed direct optical energy gap value was determined from the optical absorption spectra: in both cases, it decreases with increasing CNT or Fe 2 O 3 NP concentrations. The obtained results will be presented and discussed.
Gold bulletin, Aug 23, 2017
An evaluation of the improvement in radiotherapy obtained using gold nanoparticles embedded in th... more An evaluation of the improvement in radiotherapy obtained using gold nanoparticles embedded in the tumor tissues is presented for traditional treatments using X-rays and electrons and for innovative proton therapy. The possible nanoparticles' preparation via physical, by laser ablation in liquids, and chemical techniques is presented. The use of functionalized gold nanoparticles is discussed and results from the study of uptake and decay from mice living systems are reported. The improvement obtainable in medical images and in the dose distribution enhancement in disease tissues with respect to healthy ones is investigated.
Laser and Particle Beams, 2017
Graphene micrometric particles have been embedded into polyethylene at different concentrations b... more Graphene micrometric particles have been embedded into polyethylene at different concentrations by using chemical–physical processes. The synthesized material was characterized in terms of mechanical and optical properties, and Raman spectroscopy. Obtained targets were irradiated by using a Nd:YAG laser at intensities of the order of 1010 W/cm2 to generate non-equilibrium plasma expanding in vacuum. The laser–matter interaction produces charge separation effects with consequent acceleration of protons and carbon ions. Plasma was characterized using time-of-flight measurements of the accelerated ions. Applications of the produced targets in order to generate carbon and proton ion beams from laser-generated plasma are presented and discussed.
Deuterated polyethylene targets have been irradiated by means of a 10 16 W/cm 2 laser using 600 J... more Deuterated polyethylene targets have been irradiated by means of a 10 16 W/cm 2 laser using 600 J pulse energy, 1315 nm wavelength, 300 ps pulse duration and 70 micron spot diameter. The plasma parameters were measured using on-line diagnostics based on ion collectors, SiC detectors and plastic scintillators, all employed in time-of-flight configuration. In addition, a Thomson parabola spectrometer, an X-ray streak camera, and calibrated neutron dosimeter bubble detectors were employed. Characteristic protons and neutrons at maximum energies of 3.0 MeV and 2.45 MeV, respectively, were detected, confirming that energy spectra of reaction products coming from deuterium-deuterium nuclear fusion occur. In thick advanced targets a fusion rate of the order of 2 × 10 8 fusions per laser shot was calculated.
Laser and Particle Beams, 2017
A ns Nd:Yag laser, at intensity of 1010 W/cm2 is employed to generate carbon and aluminum non-equ... more A ns Nd:Yag laser, at intensity of 1010 W/cm2 is employed to generate carbon and aluminum non-equilibrium plasmas at a temperature of about 33 eV accelerating ions at energies of the order of 130 eV per charge state. The ion emission occurs manly along the normal to the target surface and can be detected using ion collectors employed in time-of-flight configuration. The application of magnetic field along the axe of the ion emission permits to focalize the ion emission enhancing the detected ion current. The formation of electron traps, due to the magnetic force lines, drives the ion acceleration improving their kinetic energy. Different applications can make use of these results to increase the flow of charged particles and their energy employing appropriate static magnetic fields, as it will be presented and discussed.
Journal of Electronic Materials, 2017
4H-SiC silicon carbide (SiC) Schottky diodes, with a 25 lm thick n-type epitaxial active layer an... more 4H-SiC silicon carbide (SiC) Schottky diodes, with a 25 lm thick n-type epitaxial active layer and a very thin front electrode contact are studied and proposed for the detection of low energetic ions. For a first evaluation of the detection properties of the SiC detectors, a standard alpha emitting radiation source was used obtaining an energy resolution of 0.85% at 5.15 MeV energy. Then the devices were employed to monitor low energetic alpha particles. From these tests it was found that the 4H-SiC diodes are able to monitor the alpha particles backscattered by different single and multilayers metallic targets (Au, Ag, Cu on Si substrates) in the energy range between 300 keV and 600 keV. In this energy range a linear energy response and a good energy resolution, close to those of a traditional commercial silicon detector, were obtained. The possibility to use these detectors for material analysis and for plasma monitoring is also discussed.
Gold Bulletin, 2017
An evaluation of the improvement in radiotherapy obtained using gold nanoparticles embedded in th... more An evaluation of the improvement in radiotherapy obtained using gold nanoparticles embedded in the tumor tissues is presented for traditional treatments using X-rays and electrons and for innovative proton therapy. The possible nanoparticles' preparation via physical, by laser ablation in liquids, and chemical techniques is presented. The use of functionalized gold nanoparticles is discussed and results from the study of uptake and decay from mice living systems are reported. The improvement obtainable in medical images and in the dose distribution enhancement in disease tissues with respect to healthy ones is investigated.
Micromachines
SiC detectors based on a Schottky junction represent useful devices to characterize fast laser-ge... more SiC detectors based on a Schottky junction represent useful devices to characterize fast laser-generated plasmas. High-intensity fs lasers have been used to irradiate thin foils and to characterize the produced accelerated electrons and ions in the target normal sheath acceleration (TNSA) regime, detecting their emission in the forward direction and at different angles with respect to the normal to the target surface. The electrons’ energies have been measured using relativistic relationships applied to their velocity measured by SiC detectors in the time-of-flight (TOF) approach. In view of their high energy resolution, high energy gap, low leakage current, and high response velocity, SiC detectors reveal UV and X-rays, electrons, and ions emitted from the generated laser plasma. The electron and ion emissions can be characterized by energy through the measure of the particle velocities with a limitation at electron relativistic energies since they proceed at a velocity near that o...
Polymers
Thin sheets of ultra-high molecular weight polyethylene (UHMWPE), both in pristine form and conta... more Thin sheets of ultra-high molecular weight polyethylene (UHMWPE), both in pristine form and containing carbon nanotubes (CNTs) or Fe2O3 nanoparticles (NPs) at different concentrations, were prepared. The CNT and Fe2O3 NP weight percentages used ranged from 0.01% to 1%. The presence of CNTs and Fe2O3 NPs in UHMWPE was confirmed by transmission and scanning electron microscopy and by energy dispersive X-ray spectroscopy analysis (EDS). The effects of the embedded nanostructures on the UHMWPE samples were studied using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and UV–Vis absorption spectroscopy. The ATR-FTIR spectra show the characteristic features of the UHMWPE, CNTs, and Fe2O3. Concerning the optical properties, regardless of the type of embedded nanostructures, an increase in the optical absorption was observed. The allowed direct optical energy gap value was determined from the optical absorption spectra: in both cases, it decreases with increa...
Gold Bulletin, 2019
This work introduces an innovative new method to transport gold nanoparticles (Au-NPs) toward spe... more This work introduces an innovative new method to transport gold nanoparticles (Au-NPs) toward specific organs using as transporter the M13 filamentous phage. The aim is to improve the radiotherapy efficiency by injecting gold nanoparticles in the tumor tissues in order to increase the effective atomic number and, consequently, to produce higher locally deposited doses. The biocompatible Au-NPs can be bonded to the phage surface for their transport in the biological fluids and tissues. M13 phages can be prepared to arrive in specific tissues and organs depending on their biochemical preparation and functionalization. Evidence about the real attachment of spherical Au-NPs, 10 nm in diameter, to the M13 phages is obtained using different microscopies. Other analyses have been also performed to evaluate the number of gold nanoparticles that can be transported by M13 phages inside the organism. Our results on the study of the spherical Au-NP size distribution, deduced by AFM, EFM, and TEM analyses, have indicated that in average, 2 couples of Au-NPs are attached to each phage. Moreover, the size of the NPs ranges between 10 and 30 nm, demonstrating a little aggregation of the nanoparticles, which remain usefully sized to be vehicled with the blood flux towards specific organs.
Gold Bulletin, 2017
We propose very promising gold nanoparticles for medicinal diagnostic and therapy. The synthesis ... more We propose very promising gold nanoparticles for medicinal diagnostic and therapy. The synthesis of gold nanoparticles by using laser ablation in liquids and their physical characterization, jointed with their surface plasmon resonance absorptions, high density and atomic number, and high biocompatibility, is presented in the first part of the article. The second part describes aspects of X-ray absorption enhancement due to the presence of gold nanoparticles in the biological liquids and tissues. The third part of the manuscript shows the applications of gold nanoparticles as contrast medium for X-ray diagnostic imaging. We also discuss possibilities of improvement of the radio therapeutic dose released to disease tissues, to which the gold nanoparticles can be locally absorbed, transported, or injected.
Journal of Materials Science: Materials in Medicine, 2017
The wetting ability of water and of some biological liquids was measured on different biocompatib... more The wetting ability of water and of some biological liquids was measured on different biocompatible surfaces with and without different colloidal metals. Insoluble nanoparticles disperse in biological tissues enhance some properties, such as the interface adhesion between two surfaces, the X-ray contrast of medical images and the absorbed dose during radiotherapy treatments. The introduction of nanoparticles in the liquids generally improves the wetting ability and changes other properties of the solution, due to the different distribution of the adhesion forces, to the nature, morphology and concentration of the added nanoparticles. An investigation on the contact angle of the liquid drops, physiological liquids, including the human blood, placed on different substrates (polymers, ceramics and metals) with and without the use of metallic nanoparticles is presented, evaluated and discussed.
Coatings, 2021
Polydimethylsiloxane (PDMS) is a silicone-elastomer that owes its large application in the field ... more Polydimethylsiloxane (PDMS) is a silicone-elastomer that owes its large application in the field of stretchable electronics to its chemical and thermal stability, transparency, flexibility, non-toxicity, compatibility, and low cost. PDMS is a versatile material because it can be used both as an elastic substrate and, after functionalization, as an active material for the design of stretchable electronics. One possible route for the functionalization of PDMS, thus becoming an active material together with numerous metals and semiconductors, is the embedding of conductive nanomaterials. Presently, pulsed laser deposition (PLD) and laser-induced backward transfer (LIBT) are used to deposit carbon- based material on polydimethylsiloxane. In this study, we explore and compare the surface treatments, advantages, and disadvantages of both different employed techniques in different environments. The modification of the wettability, elasticity, morphology, composition, and optical characteri...
Journal of Instrumentation, 2015
Non-equilibrium plasma generated by nanosecond pulsed laser are characterized by solid state 4H-S... more Non-equilibrium plasma generated by nanosecond pulsed laser are characterized by solid state 4H-SiC interdigit Schottky diodes and by a large area ion collector detector, both connected in time-of-flight configuration. Plasma generated by irradiation of different metallic targets through a pulsed laser with a 1010 W/cm2 intensity and a 200 mJ energy, where monitored. In this paper we demonstrate that the interdigit 4H-SiC diode is able to detect ultraviolet radiation and soft X-rays, with energy of the order of 20 eV with very short rise time, of a few nanoseconds, and high efficiency, comparable with the performance of traditional large area ion collectors. Thanks to their millimetric size, solid state 4H-SiC detectors are good candidates for the fabrication of array systems for the spatial distribution measurement of plasma radiation. Moreover, owing to the their high efficiency and the interdigit geometry of front electrode, 4H-SiC diodes here proposed are suitable also for low energy ions detection.
Reports of Practical Oncology & Radiotherapy, 2019
Aim: A study on the possibility to use gold nanoparticles in mammography, both for a better image... more Aim: A study on the possibility to use gold nanoparticles in mammography, both for a better image diagnostics and radiotherapy, is presented and discussed. We evaluate quantitatively the increment of dose released to the tumor enriched with Au-NPs with respect to the near healthy tissues, finding that for X-rays the increase can reach two orders of greater intensity. Background: Gold nanoparticles continue to be investigated for their potential to improve existing therapies and to develop novel therapies. They are simple to obtain, can be functionalized with different chemical approaches, are stable, non-toxic, non-immunogenic and have high permeability and retention effects in the tumor cells. The possibility to use these for breast calcified tumors to be better treated by radiotherapy is presented as a possible method to destroy the tumor. Materials and methods: The nanoparticles can be generated in water using the top-down method, should have a size of the order of 10-20 nm and be treated to avoid their coalescence. Under diagnostic X-ray monitoring, the solution containing nanoparticles can be injected locally inside the tumor site avoiding injection in healthy tissues. The concentrations that can be used should be of the order of 10 mg/ml or higher. Results: An enhancement of the computerized tomography diagnostics using 80-150 keV energy is expected, due to the higher mass X-ray coefficient attenuation with respect to other contrast media. Due to the increment of the effective atomic number of the biological tissue containing the gold nanoparticles, also an improvement of the radiotherapy effect using about 30 keV X-ray energy is expected, due to the higher photoelectric cross sections involved. Conclusions: The study carried out represents a feasibility proposal for the use of Aunanoparticles for mammographic molecular imaging aimed at radiotherapy of tumor nodules but no clinical results are presented.
The production of metallic nanoparticles using pulsed laser ablation in water is presented. The p... more The production of metallic nanoparticles using pulsed laser ablation in water is presented. The physical characterization of the produced nanoparticles is reported in terms of electronic microscopy, optical and mechanical properties, SPR, EDX, XPS and XRD spectroscopies. The applications of the prepared nanoparticles involve different scientific fields. In particular will be discussed their use to modify some properties of polymers, liquids and alloys. Special attention is devoted to the use of nanoparticles for polymeric laser welding, to the use as an image contrast medium in the biological environment and to the use of Au-NPs targeting for radiotherapy of cancer tissues.
Handbook of Cultural Heritage Analysis, 2022
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Papers by Lorenzo Torrisi