RICARDO ELGUL SAMAD

RICARDO ELGUL SAMAD

(Fonte: Lattes)

Resumo

Has graduation at Bacharelado Em Física by Instituto de Física da Usp (1993) , specialization at V Escola Jorge André Swieca de Óptica Quântica by Centro Brasileiro de Pesquisas Físicas (1996) , specialization at 1a Escola de Óptica Aplicada by Instituto de Física da Usp (1998) , specialization at Training Course On Instrumentation For Ultrashort by International Centre For Science And High Technology (2002) , specialization at An Introduction to Femtosecond Laser Techniques by The International Society For Optical Engineering (2005) , specialization at IV Escola Jorge André Swieca de Óptica Quântica by Universidade Estadual de Campinas (1994) , specialization at Workshop On Thin Films by International Centre For Theoretical Physics (1999) , specialization at Winter College On Optics by International Centre For Theoretical Physics (1998) , specialization at Winter College On Ultrafast Non Linear Optics by International Centre For Theoretical Physics (2002) , master's at Física do Estado Sólido by Instituto de Física da Usp (1997) and Ph.D. at Física do Estado Sólido by Instituto de Física da Usp (2006) . Currently is of Instituto de Pesquisas Energéticas e Nucleares, Revisor de periódico of Applied Optics, Revisor de periódico of Optics Letters, of Universidade de São Paulo, Revisor de periódico of Journal of Applied Physics, of Comissão Nacional de Energia Nuclear, Revisor de periódico of OPTICS EXPRESS, Revisor de periódico of OPTICS AND LASERS IN ENGINEERING, Revisor de periódico of JOURNAL OF APPLIED PHYSICS, Revisor de projeto de fomento of Conselho Nacional de Desenvolvimento Científico e Tecnológico, Revisor de projeto de fomento of Fundação de Amparo à Pesquisa do Estado de São Paulo, Revisor de projeto de fomento of Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Revisor de periódico of Papers in Physics, Revisor de periódico of Optics and Laser Technology, Membro de corpo editorial of SBFoton Newsletter, of University of Nebraska/Lincoln e of Centro Tecnológico da Marinha Em Sao Paulo. Has experience in the area of Physics , with emphasis on Física da Matéria Condensada. Focused, mainly, in the subjects: femtossegundos, Terawatt, Cr:LiSAF, Amplificacao de Pulsos Laser, Lasers. (Text obtained from the Currículo Lattes on November 25th 2021)

Ricardo Elgul Samad bacharelou-se em Física em 1993, obteve o seu mestrado em Física do Estado Sólido em 1997, e concluiu o doutorado também em Física do Estado Sólido em 2006, todos pelo Instituto de Física da USP. Atualmente é Pesquisador do Centro de Lasers e Aplicações Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP). Publicou 69 artigos em periódicos especializados que possuem mais de 550 citações, 3 capítulos de livros e mais de 90 trabalhos em anais de eventos, além de ter submetido 2 pedidos de patente. Desde a sua Iniciação Científica trabalha no desenvolvimento e em aplicações de lasers de estado sólido, e no seu doutorado iniciou atividades de pesquisa com lasers de pulsos ultracurtos. Atualmente trabalha com aplicações de pulsos ultracurtos e a interação destes com a matéria, como na ablação e usinagem de sólidos por laser, geração de plasma induzida por pulsos ultracurtos e modificação de materiais resultante de estados extremos de temperatura e pressão gerados pelos pulsos ultracurtos, e técnicas de geração de harmônicos para viabilizar novas fontes de luz na região do UV profundo e raios X moles. Recentemente tem trabalhado com aceleração de partículas por pulsos laser ultracurtos. (Texto extraído do Currículo Lattes em 25 nov. 2021)

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Evaluation of adhesive strength in dentin iradiated with ultra short pulse laser (FS) at various energy densities using two adhesive strategies
2024 - PENHA-JUNIOR, T.; RODRIGUES, M.A.P.; PECORARI, V.; VIEIRA JUNIOR, N.D.; ZEZELL, D.M.; SAMAD, R.E.; DUTRA-CORREA, M.
Goal: The study evaluated the adhesive strength of the tooth-restoration interface, promoted by ultrashort pulse laser irradiation, and its influence on the microtensile adhesive strength (µTBS) with different adhesive strategies. Method: Fifty healthy teeth were evaluated, restored with the Single Bond Universal adhesive, using two adhesion strategies: ecth-and-rinse, total acid etching (E) and self-etch, self-etching (SE). To evaluate the adhesive interface, the samples were divided into groups SE (self-etch) and E (etch), and each group was irradiated with pulse fluences of 2 J/cm2, 4 J/cm2, 6 J/cm2 and 8 J/cm2. After irradiation, and restorations were carried out with Z350XT resin, the samples were sectioned with cuts perpendicular to each other, producing toothpicks, which were subjected to microtraction. The Bartlet and Shapiro-Wilks tests were performed and then Two-way ANOVA was applied with 2 additional treatments. When observing differences between factors or interactions, the Dunnett test was applied to compare groups with Controls and Tukey for multiple two-by-two comparisons between the transformed means (α<0.05). The percentages of failure types (µTBS) were calculated in the different groups and the Fisher's Exact test was applied (α<0.05). Result: The results demonstrate that laser irradiation (fs), regardless of the energy density used, did not interfere with the performance of the material at the adhesive interface without prior conditioning, as the values obtained were similar to each other (32-35 MPa). Conclusion: It was concluded that irradiation with different energy densities did not change the adhesive strength of the SE groups, as the groups had similar results between themselves and the Control. However, acid conditioning affected the irradiated groups, as the Control (with acid) presented higher values with a statistical difference in relation to the others.
FTIR imaging on glass substrates evaluation of histological skin burn injuries specimens treated by femtosecond laser pulses
2022 - ZEZELL, DENISE; CASTRO, PEDRO; DEL-VALLE, MATHEUS; CAMILLO-SILVA, CARLOS; SAMAD, RICARDO; DE ROSSI, WAGNER; SANTOS, MOISES
Burn injuries continue to be one of the leading causes of unintentional death and injury in low- and middle-income countries [1]. Burns are considered an important public health problem, because in addition to physical problems that can lead the patient to death, they cause psychological and social damage. An estimated 180,000 deaths every year are caused by burns [2]. The use of infrared (IR) spectroscopy for studying biological specimens is nowadays a wide and active area of research. The IR microspectroscopy has proved to be an ideal tool for investigating the biochemical composition of biological samples at the microscopic scale, as well as its fast, sensitive, and label-free nature [3]. IR image spectral histopathology has shown great promise as an important diagnostic tool, with the potential to complement current pathological methods, reducing subjectivity in biopsy samples analysis. However, the use of IR transmissive substrates which are both fragile and prohibitively very expensive, hinder the clinical translation. The goal of this study is to evaluate the potential of discriminating healing process, in burned skin specimens treated with ultrashort pulses laser 3 days after the burn. This study is considering a previous paper [4], in which it analyzed only micro-ATR-FTIR spectra of a frozen sample point. The specimens were obtained from third degree burn wound. The wounds treatment were performed three days after the burn, and the animals were sacrificed 3 and 14 days post-treatment. Using coverslipped H&E stained tissue on glass from previous histopathological analysis and applying the analytical techniques PCA and K-means on N−H, O−H, and C−H stretching regions occurring at 2500−3800 cm−1 (high wavenumber region), were possible to discriminate burned epidermal and dermal regions from irradiated in same regions on sample. In the figures is shown the average spectrum at (a) day 3 and (b) day 14. , in both there were increase of burned+laser treated bands. The great potential of this study was to analyse coverslipped H&E stained tissue on glass, without compromising the histopathologist practices and contribute for clinical translation.
Femtosecond Ti: Sa ultra short-pulse laser irradiation effects on the properties and morphology of the zirconia surface after ageing
2021 - KIYAN, VANESSA H.; RODRIGUES, FLAVIA P.; SAMAD, RICARDO E.; ZEZELL, DENISE M.; BOTTINO, MARCO A.; LIMA, NELSON B. de; SARACENI, CINTIA H.C.
Femtosecond pulses from a Ti:Sapphire laser were used to irradiate specimens of yttria-stabilised (35% mol) tetragonal zirconia (Y-TZP) with the purpose of studying the effects of the irradiations on their surface properties and morphology after ageing. Zirconia disks were divided into eight groups (n = 32) according to their surface treatment and subsequent ageing: Control: no treatment; sandblasting: Al2O3 sandblasting 50 μm; and ultrashort laser pulses irradiation with 25 μJ pulses, considering two different scanning steps based on the width between two grooves. These groups were duplicated and submitted to ageing. The surfaces were analysed using scanning electron microscopy (SEM), and X-ray diffraction. A finite element analysis, a biaxial flexure test, as well as fractographic and Weibull analyses, were performed. The strengths of the disks were statistically different for the treatment factor, and the principal stresses seemed to be concentrated at the centre of the specimens, as predicted by the computer simulations. Ageing decreased the strengths for all groups and increased the Weibull modulus for the laser group with the 40 μm-width between two grooves. The sandblasting group presented the highest monoclinic phase peak. Although the most significant strength was found within the sandblasting group, the phase transformation was favourable to the laser groups. The Weibull modulus was higher for the laser group with the 60 μm-width between two grooves, confirming the highest homogeneity of its failure distribution. Regardless of the surface treatment, strength was decreased with ageing in all groups. The femtosecond Ti:Sa ultra-short pulse laser irradiation can be suggested as an alternative to the gold standard sandblasting in longterm Y-TZP zirconia rehabilitations, such as crowns and veneers.
Evaluation of the adhesive strength in dentin after irradiation with Ti:Sapphire ultrashort laser pulses
2019 - PENHA JUNIOR, TARCISO; RODRIGUES, MONICA de A.P.; ZEZELL, DENISE M.; VIEIRA JUNIOR, NILSON D.; SAMAD, RICARDO E.; DUTRA-CORREA, MARISTELA
This study was done to evaluate whether the irradiation of dentine with ultrashort laser pulses prior to adhesive procedures contributes to increase the adhesive resistance to microtraction essays. Twenty-four human teeth (third molars) were used, divided into 4 groups (n=6): standard adhesive procedures with etch-rinse adhesive were used in the control group, and in the experimental groups, the dentin was irradiated by 25 fs pulses prior to the adhesive procedures, with varying fluences. One tooth from each group was used to evaluate its surface roughness. After 24h, the teeth were sectioned with perpendicular cuts, producing toothpicks that were submitted to the microtraction test. The results showed that the groups irradiated with fluences under 4 J/cm² presented similar results among themselves, comparable to the control group, while the group irradiated with 8 J/cm² showed lower adhesive strength. We propose that the adhesive strength and surface roughness reduction resulting from the fluence increase is probably related to the shielding arising from an electron plasma formation during the ablation, decreasing the material removal efficiency. Nevertheless, the lower energy densities did not affect the adhesiveness, maintaining values similar to the control.
High intensity femtosecond lasers at IPEN
2018 - SAMAD, R.E.; MALDONADO, E.P.; COURROL, L.C.; ROSSI, W. de; BALDOCHI, S.L.; ZEZELL, D.M.; VIEIRA JUNIOR, N.D.
High intensity femtosecond (fs) lasers have become an affordable and versatile tool to modify all kinds of materials and to characterize the induced modifications. These capabilities derive from the ultrafast interaction between the electromagnetic field and matter, which distinguishes this kind of laser from all others. In the time frame of the fs pulses, the predominant interaction with the matter occurs through electron excitation, and several processes take place with increasing intensity: nonlinear excitation, ionization and recombination, which occur in a non-selective way due to the short time of interaction. The after-pulse evolution is due mainly to electrostatic interactions, involving the relaxation of the electrons energy to and between atoms. Coulomb and phase explosions, for example, are predominant for intensities in the range of TW/cm2 to PW/cm2, and they ablate all material (metals, polymers, dielectrics, etc) with a very high precision due to the small heat effect zone of these interactions. At the High Intensity Ultrashort Pulses Lasers Laboratory at IPEN we daily generate femtosecond pulses with intensities of 100 TW/cm2 and above. In this work we describe results obtained by our group using ultrashort pulses from Ti:Sapphire lasers covering the creation of color centers in crystals, glasses and polymers, the inscription of waveguides and the creation of surface structures that can range from the colorization of metals to the manufacture of microfluidic circuits, as well as the removal of burned tissue from living organisms. The pulses can also be used to study how defects pileup during the etching of a solid by superimposing pulses, and how the ablation process is affected by the incubation. At higher intensities the pulses can modify materials, and we present the controlled synthesis of nanoparticles, and the modification of graphite into diamond by the shockwaves generated during the ablation as a product of an evolving underdense plasma that generates local high temperatures and pressures. Also, the materials characterization is possible by spectroscopic measurements of the plasma elements atomic lines. Furthermore, we present results on the production of radiation on the deep ultraviolet by generation of harmonics of the laser interaction with gases, and also our recent efforts towards the acceleration of electrons by ultrashort laser pulses. Both the harmonics and electrons ultrafast beams could be used to modify and characterize materials by pump-probe, spectroscopic and diffraction measurements.
Analysis of temperature on microscope slide by a boron pulsed laser deposition process
2018 - SILVA, ANDRE F.; COSTA, PRISCILA; MACHADO, NOE G.P.; SAMAD, RICARDO E.; ZEZELL, DENISE M.; RAELE, MARCUS P.; ZAMATARO, CLAUDIA B.
A boron thin ¯lm can be used for neutrons conversion and in electrically charged particles and further detection. Since boron has a high evaporation temperature and the thickness of the boron layer needs to have few microns, pulsed laser deposition also known as PLD can be used. When producing thin ¯lms with the PLD technique, the target absorbs energy promoting the material ablation creating a plasma plume that deposits material on a substrate, thus creating a thin ¯lm. Since all the deposition occurs in a vacuum chamber, the residual heat of the plasma that condensate at the substrate can build up, thus potentially source of concern if the substrate sensitive to temperature somehow. This work reports the analysis of the variation of temperature in a microscope slide (substrate) as a function of the energy of femtosecond laser pulses. For measuring the substrate temperature a type-K thermocouple was used together with associated electronics. The thermocouple was ¯xed to the back of substrate with thermal grease for vacuum and connected to the microchip using a feed through in the vacuum chamber. Was detected the increase of the substrate+¯lm starting at 6oC from initial temperature (room) for the minimal laser energy 100 microjoules (25 femtoseconds).
Mercury amalgam diffusion in human teeth probed using femtosecond LIBS
2017 - BELLO, LICIANE T.; ANA, PATRICIA A. da; SANTOS JUNIOR, DARIO; KRUG, FRANCISCO J.; ZEZELL, DENISE M.; VIEIRA JUNIOR, NILSON D.; SAMAD, RICARDO E.
In this work the diffusion of mercury and other elements from amalgam tooth restorations through the surrounding dental tissue (dentin) was evaluated using femtosecond laser-induced breakdown spectroscopy (fs-LIBS). To achieve this, seven deciduous and eight permanent extracted human molar teeth with occlusal amalgam restorations were half-sectioned and analyzed using pulses from a femtosecond laser. The measurements were performed from the amalgam restoration along the amalgam/dentin interface to the apical direction. It was possible to observe the presence of metallic elements (silver, mercury, copper and tin) emission lines, as well as dental constituent ones, providing fingerprints of each material and comparable data for checking the consistence of the results. It was also shown that the elements penetration depth values in each tooth are usually similar and consistent, for both deciduous and permanent teeth, indicating that all the metals diffuse into the dentin by the same mechanism.We propose that this diffusion mechanism is mainly through liquid dragging inside the dentin tubules. The mercury diffused further in permanent teeth than in deciduous teeth, probably due to the longer diffusion times due to the age of the restorations. It was possible to conclude that the proposed femtosecond-LIBS system can detect the presence of metals in the dental tissue, among the tooth constituent elements, and map the distribution of endogenous and exogenous chemical elements, with a spatial resolution that can be brought under 100 μm.
Multimodal evaluation of ultra-short laser pulses treatment for skin burn injuries
2017 - SANTOS, MOISES O. dos; LATRIVE, ANNE; CASTRO, PEDRO A.A. de; ROSSI, WAGNER de; ZORN, TELMA M.T.; SAMAD, RICARDO E.; FREITAS, ANDERSON Z.; CESAR, CARLOS L.; VIEIRA JUNIOR, NILSON D.; ZEZELL, DENISE M.
Thousands of people die every year from burn injuries. The aim of this study is to evaluate the feasibility of high intensity femtosecond lasers as an auxiliary treatment of skin burns. We used an in vivo animal model and monitored the healing process using 4 different imaging modalities: histology, Optical Coherence Tomography (OCT), Second Harmonic Generation (SHG), and Fourier Transform Infrared (FTIR) spectroscopy. 3 dorsal areas of 20 anesthetized Wistar rats were burned by water vapor exposure and subsequently treated either by classical surgical debridement, by laser ablation, or left without treatment. Skin burn tissues were noninvasively characterized by OCT images and biopsied for further histopathology analysis, SHG imaging and FTIR spectroscopy at 3, 5, 7 and 14 days after burn. The laser protocol was found as efficient as the classical treatment for promoting the healing process. The study concludes to the validation of femtosecond ultra-short pulses laser treatment for skinburns, with the advantage of minimizing operatory trauma.
Imaging of nonlinear microscopy of burned skin treated by ultra-high intensity laser pulses
2014 - SANTOS, MOISES O. dos; BENETTI, CAROLINA; PELEGATI, VITOR B.; CESAR, CARLOS L.; ROSSI, WAGNER de; SAMAD, RICARDO E.; VIEIRA JUNIOR, NILSON D.; ZORN, TELMA M.T.; ZEZELL, DENISE M.
Skin ablation using high intensity femtosecond laser
2011 - SANTOS, MOISES O.; GOULART, VIVIANE P.; ROSSI, WAGNER; FREITAS, ANDERSON Z.; CORREA, PAULO R.; SAMAD, RICARDO E.; VIEIRA JUNIOR, NILSON D.; ZEZELL, DENISE M.