Assis - FCLAS - Faculdade de Ciências e Letras

URI Permanente para esta coleçãohttps://hdl.handle.net/11449/253735

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Agora exibindo 1 - 20 de 1986

Enhancing phototoxicity in human colorectal tumor cells through nanoarchitectonics for synergistic photothermal and photodynamic therapies
(ACSPublications, 2024-04-09) Almeida Junior, Alexandre Mendes ; Ferreira, André Satoshi ; Camacho, Sabrina Alessio ; Moreira, Lucas Gontijo ; Toledo, Karina Alves ; Oliveira Junior, Osvaldo Novais ; Aoki, Pedro Henrique Benites ; Universidade Estadual Paulista (Unesp)
Phototherapies are promising for noninvasive treatment of aggressive tumors, especially when combining heat induction and oxidative processes. Herein, we show enhanced phototoxicity of gold shell-isolated nanorods conjugated with toluidine blue-O (AuSHINRs@TBO) against human colorectal tumor cells (Caco-2) with synergic effects of photothermal (PTT) and photodynamic therapies (PDT). Mitochondrial metabolic activity tests (MTT) performed on Caco-2 cell cultures indicated a photothermal effect from AuSHINRs owing to enhanced light absorption from the localized surface plasmon resonance (LSPR). The phototoxicity against Caco-2 cells was further increased with AuSHINRs@TBO where oxidative processes, such as hydroperoxidation, were also present, leading to a cell viability reduction from 85.5 to 39.0%. The molecular-level mechanisms responsible for these effects were investigated on bioinspired tumor membranes using Langmuir monolayers of Caco-2 lipid extract. Polarization-modulation infrared reflection–absorption spectroscopy (PM-IRRAS) revealed that the AuSHINRs@TBO incorporation is due to attractive electrostatic interactions with negatively charged groups of the Caco-2 lipid extract, resulting in the expansion of surface pressure isotherms. Upon irradiation, Caco-2 lipid extract monolayers containing AuSHINRs@TBO (1:1 v/v) exhibited ca. 1.0% increase in surface area. This is attributed to the generation of reactive oxygen species (ROS) and their interaction with Caco-2 lipid extract monolayers, leading to hydroperoxide formation. The oxidative effects are facilitated by AuSHINRs@TBO penetration into the polar groups of the extract, allowing oxidative reactions with carbon chain unsaturations. These mechanisms are consistent with findings from confocal fluorescence microscopy, where the Caco-2 plasma membrane was the primary site of the cell death induction process.
Photochemical outcomes triggered by gold shell-isolated nanorods on bioinspired nanoarchitectonics for bacterial membranes
(Elsevier, 2023-08-19) Almeida Junior, Alexandre Mendes ; Moreira, Lucas Gontijo ; Camacho, Sabrina Alessio ; Ferreira, Fabiana G. ; Conceição, Katia ; Tada, Dayane Batista ; Aoki, Pedro Henrique Benites ; Universidade Estadual Paulista (Unesp)
Boosted by the indiscriminate use of antibiotics, multidrug-resistance (MDR) demands new strategies to combat bacterial infections, such as photothermal therapy (PTT) based on plasmonic nanostructures. PTT efficiency relies on photoinduced damage caused to the bacterial machinery, for which nanostructure incorporation into the cell envelope is key. Herein, we shall unveil the binding and photochemical mechanisms of gold shell-isolated nanorods (AuSHINRs) on bioinspired bacterial membranes assembled as Langmuir and Langmuir-Schaefer (LS) monolayers of DOPE, Lysyl-PG, DOPG and CL. AuSHINRs incorporation expanded the isotherms, with stronger effect on the anionic DOPG and CL. Indeed, FTIR of LS films revealed more modifications for DOPG and CL owing to stronger attractive electrostatic interactions between anionic phosphates and the positively charged AuSH INRs, while electrostatic repulsions with the cationic ethanolamine (DOPE) and lysyl (Lysyl-PG) polar groups might have weakened their interactions with AuSHINRs. No statistical difference was observed in the surface area of irradiated DOPE and Lysyl-PG monolayers on AuSHINRs, which is evidence of the restricted nano structures insertion. In contrast, irradiated DOPG monolayer on AuSHINRs decreased 4.0 % in surface area, while irradiated CL monolayer increased 3.7 %. Such results agree with oxidative reactions prompted by ROS gener ated by AuSHINRs photoactivation. The deepest AuSHINRs insertion into DOPG may have favored chain cleavage while hydroperoxidation is the mostly like outcome in CL, where AuSHINRs are surrounding the polar groups. Furthermore, preliminary experiments on Escherichia coli culture demonstrated that the electrostatic interactions with AuSHINRs do not inhibit bacterial growth, but the photoinduced effects are highly toxic, resulting in microbial inactivation.
Photochemical outcomes triggered by gold shell-isolated nanorods on bioinspired nanoarchitectonics for bacterial membranes
(Elsevier, 2023-08-19) Almeida Junior, Alexandre Mendes de ; Moreira, Lucas Gontijo ; Camacho, Sabrina Aléssio ; Ferreira, Fabiana ; Conceição, Katia da ; Tada, Dayane Batista ; Aoki, Pedro Henrique Benites ; UNIFESP
Boosted by the indiscriminate use of antibiotics, multidrug-resistance (MDR) demands new strategies to combat bacterial infections, such as photothermal therapy (PTT) based on plasmonic nanostructures. PTT efficiency relies on photoinduced damage caused to the bacterial machinery, for which nanostructure incorporation into the cell envelope is key. Herein, we shall unveil the binding and photochemical mechanisms of gold shell-isolated nanorods (AuSHINRs) on bioinspired bacterial membranes assembled as Langmuir and Langmuir-Schaefer (LS) monolayers of DOPE, Lysyl-PG, DOPG and CL. AuSHINRs incorporation expanded the isotherms, with stronger effect on the anionic DOPG and CL. Indeed, FTIR of LS films revealed more modifications for DOPG and CL owing to stronger attractive electrostatic interactions between anionic phosphates and the positively charged AuSH INRs, while electrostatic repulsions with the cationic ethanolamine (DOPE) and lysyl (Lysyl-PG) polar groups might have weakened their interactions with AuSHINRs. No statistical difference was observed in the surface area of irradiated DOPE and Lysyl-PG monolayers on AuSHINRs, which is evidence of the restricted nano structures insertion. In contrast, irradiated DOPG monolayer on AuSHINRs decreased 4.0 % in surface area, while irradiated CL monolayer increased 3.7 %. Such results agree with oxidative reactions prompted by ROS gener ated by AuSHINRs photoactivation. The deepest AuSHINRs insertion into DOPG may have favored chain cleavage while hydroperoxidation is the mostly like outcome in CL, where AuSHINRs are surrounding the polar groups. Furthermore, preliminary experiments on Escherichia coli culture demonstrated that the electrostatic interactions with AuSHINRs do not inhibit bacterial growth, but the photoinduced effects are highly toxic, resulting in microbial inactivation.
Unveiling the mechanisms underlying photothermal efficiency of gold shell-isolated nanoparticles (AuSHINs) on ductal mammary carcinoma cells (BT-474)
(Elsevier, 2023-07-19) Kobal, Mirella Boaro ; Camacho, Sabrina Aléssio ; Moreira, Lucas Gontijo ; Toledo, Karina Alves ; Tada, Dayane Batista ; Aoki, Pedro Henrique Benites ; UNIFESP
Gold nanoparticles are valuable photothermal agents owing to their efficient photothermal conversion, photo bleaching resistance, and potential surface functionalization. Herein, we combined bioinspired membranes with in vitro assays to elicit the molecular mechanisms of gold shell-isolated nanoparticles (AuSHINs) on ductal mammary carcinoma cells (BT-474). Langmuir and Langmuir-Schaefer (LS) films were handled to build bio membranes from BT-474 lipid extract. AuSHINs incorporation led to surface pressure-area (π-A) isotherms expansion, increasing membrane flexibility. Fourier-transform infrared spectroscopy (FTIR) of LS multilayers revealed electrostatic AuSHINs interaction with head portions of BT-474 lipid extract, causing lipid chain disorganization. Limited AuSHINs insertion into monolayer contributed to hydroperoxidation of the unsaturated lipids upon irradiation, consistently with the surface area increments of ca. 2.0%. In fact, membrane disruption of irradiated BT-474 cells containing AuSHINs was confirmed by confocal microscopy and LDH leakage, with greater damage at 2.2 × 10^(13) AuSHINs/mL. Furthermore, the decrease in nuclei dimensions indicates cell death through photoinduced damage.
Conjugated linoleic acid supplementation changes prostaglandin concentration ratio and alters the expression of genes involved in maternal-fetal recognition from bovine trophoblast cells in vitro
(2023-08-01) Bueno Cordeiro Maldonado, Mariângela ; de Castro Lourenço, Valeska ; de Oliveira Bezerra, Lucas ; Feltrin, Isabella Rio ; Mendes, Adriano Felipe ; Rocha, Cecilia Constantino ; Pugliesi, Guilherme ; Ealy, Alan D. ; Membrive, Claudia Maria Bertan ; Nogueira, Marcelo Fábio Gouveia ; Universidade Estadual Paulista (UNESP) ; University of Florida (UF-ANS) ; Universidade de São Paulo (USP) ; Virginia Tech
Early embryonic mortality caused by maternal-fetal recognition failure in the three weeks after fertilization represents a major cause of reproductive inefficiency in the cattle industry. Modifying the amounts and ratios of prostaglandin (PG) F2α and PGE2 can benefit the establishment of pregnancy in cattle. Adding conjugated linoleic acid (CLA) to endometrial and fetal cells culture affects PG synthesis, but its effect on bovine trophoblast cells (CT-1) is unknown. The aim of this study was to determine the effects of CLA (a mixture of cis- and trans-9, 11- and −10,12-octadecadienoic acids) on PGE2 and PGF2α synthesis and the expression of transcripts involved with maternal-fetal recognition of bovine trophectoderm. Cultures of CT-1 were exposed to CLA for 24, 48 and 72 h. Transcript abundance was determined by qRT-PCR and hormone profiles were quantified by ELISA. The PGE2 and PGF2α concentrations were reduced in the culture medium of CLA-exposed CT-1 compared to that of unexposed cells. Furthermore, CLA supplementation increased the PGE2:PGF2α ratio in CT-1 and had a quadratic effect (P < 0.05) on the relative expression of MMP9, PTGES2, and PTGER4. The relative expression levels of PTGER4 were reduced (P < 0.05) in CT-1 cultured with 100 μM CLA than in the unsupplemented and 10 μM-CLA groups. Treatment of CT-1 with CLA decreased PGE2 and PGF2α synthesis but a biphasic effect of CLA was observed on the PGE2:PGF2α ratio and relative abundance of transcripts with 10 μM CLA providing maximal improvements in each endpoint. Our data suggest that CLA may influence eicosanoid metabolic process and extracellular matrix remodeling.
The influence of pre-treatment on germination of three species of Catasetum (Orchidaceae)
(2023-01-01) Moraes, Milena Cristina ; Bertão, Monica Rosa ; Custódio, Ceci Castilho ; Machado-Neto, Nelson Barbosa ; Agronomy College ; Universidade Estadual Paulista (UNESP)
Asymbiotic germination techniques are successful in species of the Catasetum genus. The diverse composition of the culture media can be critical; however, viable seeds are required for asymbiotic germination. The reliable method for viability assessment is the tetrazolium test. A decisive step in the efficiency of the tetrazolium test is the seeds preconditioning with sucrose solution, which has the potential to improve germination. Therefore, this work aimed to evaluate the seed germination of three species of the genus Catasetum in culture media, preconditioned or not with sucrose solution. Seeds of the species Catasetum osculatum, Ctsm. galeritum and Ctsm. complanatum were assessed by tetrazolium test and germinated in two different media, pretreated or not with 10% sucrose solution. The statistical analysis showed that the use of sucrose pretreatment significantly increased the germination rates of the species. We conclude that the pretreatment with 10% sucrose for 24 hours, regardless of the species and the culture medium, significantly increases the germination of Ctsm. complanatum, Ctsm. galeritum and Ctsm. osculatum seeds.
Aloe vera-loaded natural rubber latex dressing as a potential complementary treatment for psoriasis
(2023-07-01) Herculano, Rondinelli Donizetti ; dos Santos, Thainá Oliveira ; de Barros, Natan Roberto ; Pegorin Brasil, Giovana Sant'Ana ; Scontri, Mateus ; Carvalho, Bruna Gregatti ; Mecwan, Marvin ; Farhadi, Neda ; Kawakita, Satoru ; Perego, Caio Humberto ; Carvalho, Flávio Alexandre ; dos Santos, André Gonzaga ; Guerra, Nayrim Brizuela ; Floriano, Juliana Ferreira ; Mussagy, Cassamo Ussemane ; Tirpáková, Zuzana ; Khorsandi, Danial ; Peirsman, Arne ; Nguyen, Huu Tuan ; Gomez, Alejandro ; Mandal, Kalpana ; de Mendonça, Ricardo José ; Li, Bingbing ; Dokmeci, Mehmet Remzi ; Jucaud, Vadim ; Universidade Estadual Paulista (UNESP) ; Terasaki Institute for Biomedical Innovation (TIBI) ; California State University ; Universidade Estadual de Campinas (UNICAMP) ; University of Caxias do Sul (UCS) ; Pontificia Universidad Católica de Valparaíso ; The University of Veterinary Medicine and Pharmacy in Košice ; Reconstructive and Aesthetic Surgery University Hospital Ghent ; Federal University of Triangulo Mineiro (UFTM)
Psoriasis is a disease that causes keratinocytes to proliferate ten times faster than normal, resulting in chronic inflammation and immune cell infiltration in the skin. Aloe vera (A. vera) creams have been used topically for treating psoriasis because they contain several antioxidant species; however, they have several limitations. Natural rubber latex (NRL) has been used as occlusive dressings to promote wound healing by stimulating cell proliferation, neoangiogenesis, and extracellular matrix formation. In this work, we developed a new A. vera-releasing NRL dressing by a solvent casting method to load A. vera into NRL. FTIR and rheological analyzes revealed no covalent interactions between A. vera and NRL in the dressing. We observed that 58.8 % of the loaded A. vera, present on the surface and inside the dressing, was released after 4 days. Biocompatibility and hemocompatibility were validated in vitro using human dermal fibroblasts and sheep blood, respectively. We observed that ~70 % of the free antioxidant properties of A. vera were preserved, and the total phenolic content was 2.31-fold higher than NRL alone. In summary, we combined the antipsoriatic properties of A. vera with the healing activity of NRL to generate a novel occlusive dressing that may be indicated for the management and/or treatment of psoriasis symptoms simply and economically.
Herbicidal Activity of Smoke Water
(2023-04-01) Garrido, Raphael Mota ; Dayan, Franck Emmanuel ; Kolb, Rosana Marta ; Universidade Estadual Paulista (UNESP) ; Colorado State University
Weeds cause more crop yield loss and increase farmers’ production costs more than any other agricultural pest worldwide. Natural extracts can be an important alternative to synthetic herbicides, or they can be one of the resources from which to discover new pesticide leads. The phytotoxic potential of smoke water was evaluated regarding germination and initial growth, prospecting for its possible herbicidal activity in weeds. Herbicidal activity was evaluated through germination, initial growth, and seedling vigor index bioassays in the laboratory and emergency with initial development bioassays in a greenhouse with smoke water solutions at 2.5, 5, 10 and 20% v/v. Experiments with two treatments were analyzed using T-tests for the parametric data and the Mann–Whitney test for the non-parametric data (p < 0.05). Experiments with three treatments or more were analyzed with a one-way ANOVA test followed by a Tukey test for the parametric data and a Kruskal–Wallis test followed by a Dunn test for the non-parametric data (p < 0.05). Linear regression was used to analyze data from the time–injury curve. The greatest effect on germination suppression (98%) was achieved when the Amaranthus viridis seeds were germinated in the laboratory with a 10% smoke water solution. Germination of Raphanus raphanistrum and Digitaria insularis was reduced by 93 and 75%, respectively, at this concentration. In greenhouse experiments, emergence of A. viridis was inhibited 81% by 20% smoke water. In laboratory initial growth experiments, 5% smoke water had the greatest inhibitory effect (94%) on A. viridis. R. raphanistrum initial growth reduction was 82%, Urochloa decumbens was 80%, D. insularis was 77% and Emilia fosbergii was 70% in the same conditions. In greenhouse development experiments, 70% of the A. viridis plants were killed by 5% smoke water treatment. These plants had 88% injury after treatment with 5% smoke water. Therefore, these findings suggest that smoke water solutions have potential as an herbicide, inhibiting the germination and initial growth of monocotyledonous and eudicotyledonous weeds. However, field tests are needed to confirm the potential of smoke water as an herbicide.
Does flooding affect the survival and primary and secondary metabolism of two species of Croton?
(2023-01-01) de Lima, Vânia Tomazelli ; de Paula Quintão Scalon, Silvana ; Cardoso, Claudia Andrea Lima ; Reis, Lucas Coutinho ; Kolb, Rosana Marta ; Universidade Estadual Paulista (UNESP) ; Universidade Federal da Grande Dourados ; Universidade Estadual de Mato Grosso do Sul (UEMS)
Key message: Both Croton species survive flooding for a considerable period, changing primary and secondary metabolism; C. urucurana is more tolerant than C. floribundus. Native tropical species with a wide distribution are subject to environmental heterogeneity. Croton floribundus and C. urucurana, for example, occur in different forest formations, such as semideciduous seasonal forest and riparian forests, in well-drained or flooded soils. To explain possible adaptive strategies that allow this congeneric pair to occupy areas subject to flooding, we studied the effects of different times of exposure to flooding on species survival and metabolism and the potential for post-flood recovery. Unlike C. urucurana, the plants of C. floribundus survived flooding for only 60 days and the post-flood period; they did not survive flooding for 90 days. In both species, flooding reduced CO2 absorption rate, stomatal conductance, Rubisco carboxylation efficiency, photochemical efficiency of the photosystem II, and shoot and root biomass; however, there was a recovery of these parameters in post-flooding. Additionally, the flooding of Croton plants increased the content of alkaloids, total phenolic compounds, flavonoids, antioxidant activity, proline, and the activity of the enzymes guaiacol peroxide and superoxide dismutase. These responses were also observed in the post-flooding period. Thus, we conclude that C. floribundus is more sensitive to flooding compared to its congeneric pair. We also conclude that the mechanisms of adaptation to flooding are related to the phenotypic plasticity of both species, including the formation of hypertrophied stem lenticels and adventitious roots, changes in primary and secondary metabolism, and production of protective molecules such as proline.
Revision of Potamobates Champion, 1898 (Hemiptera: Heteroptera: Gerridae) and description of a new genus for P. thomasi Hungerford, 1937
(2023-03-01) Floriano, Carla Fernanda Burguez ; Moreira, Felipe Ferraz Figueiredo ; Bispo, Pitágoras da Conceição ; Universidade Estadual Paulista (UNESP) ; Fundação Oswaldo Cruz
Potamobates Champion, 1898 (Hemiptera: Heteroptera: Gerridae) heretofore included 18 species distributed from southern Mexico to Peru. They display a distinct morphology, especially regarding the projections of abdominal segment VIII. Specific identification and delimitation are difficult, and the genus lacks a thorough revision and evaluation of inter- and intraspecific variation. Here, we revise Potamobates, redescribe and/or illustrate known species, and describe P. molanoi Floriano and Moreira, sp. nov. and Brailovskybates Floriano and Moreira, gen. nov. The new genus is erected for P. thomasi Hungerford, 1937 and is characterized by the following features: (1) abdomen elongated, longer than the mesothorax; (2) abdominal spiracles positioned at the center of the segments; (3) male abdominal segment VIII without projections; (4) male pygophore and proctiger not rotated in relation to the longitudinal axis of the body; (5) female abdominal tergum VIII subequal in length and width; (6) and posterior margin of female abdominal sternum VII not produced medially, with a pair of lateral projections.
OPTIMIZED METHOD FOR DNA EXTRACTION AND PCR AMPLIFICATION IN AROEIRA TREE
(2023-01-01) Silva, Jailson Do Nascimento ; Linhares, Amanda Camila Dos Santos ; Palmieri, Dario Abel ; Costa, Marcones Ferreira ; de SÁ, Gisele Holanda ; Gomes, Maria Fernanda da Costa ; Dos Santos, Michelli Ferreira ; Feitoza, Lidiane de Lima ; Valente, Sérgio Emílio Dos Santos ; Instituto Federal do Piauí ; Universidade Federal do Piauí ; Universidade Estadual Paulista (UNESP) ; Universidade Estadual do Piauí
Molecular markers are important tools in the characterization of plant genetic diversity and can provide support for conservation strategies for endangered populations. The different molecular techniques involve the evaluation of many individuals; therefore, it is crucial to have fast, efficient, and inexpensive methods for DNA extraction. Given the importance of the Aroeira (Myracrodruon urundeuva Fr. All.) it is pertinent to optimize a protocol that allows the obtainment of intact and pure DNA, aiming to assist conservation strategies for this species that is threatened with extinction. Thus, this study aimed to compare five DNA extraction methods: Dellaporta et al. (1983), Doyle and Doyle (1987) modified, Ferreira and Grattapaglia (1995), Romano and Brasileiro (2015), and Khanuja et al. (1999) and optimize the most efficient protocol for M. urundeuva. The modified DNA extraction protocol proposed by Doyle and Doyle (1987), using 100 mg of leaf tissue and 6 µl of β-mercaptoethanol was the protocol that presented the sharpest bands after DNA electrophoresis and after the reactions of amplification employing Polymerase Chain Reaction (PCR). Therefore, it is suggested to use the protocol described by Doyle and Doyle (1987) modified for the extraction of DNA from young M. urundeuva leaves to carry out techniques involving molecular markers.
Ancient History: What for? The Possibilities between Teaching and Entertainment through Digital Games
(2021-08-04) Carvalho Rossi, Andrea Lúcia Dorini de Oliveira ; Bondioli, Nelson de Paiva ; Universidade Estadual Paulista (UNESP)
There are several visions and proposals concerning the ways – and the content – to approach teaching History in schools, although it is possible to assert that there is one important consensus among the specialists: Teaching History is much more than simply teach ‘dates’ and ‘events’ expecting students to memorize them, but rather it is about working towards the development of the critical-analytical tools of the students, as well as other different transferable skills and abilities, useful in different situations of quotidian life. Based on this understanding, it is possible to see how History and its processes of learning open themselves to a myriad of possibilities and tools, especially those made available by the advances and the development of digital technologies, increasingly ubiquitous. In this sense, the present article aims at, specifically, discussing the possibilities of teaching Ancient History through digital games. Bearing that in mind, two discussions are presented concerning, first, the theoretical discussions on historical literacy – and the concepts of historicity, temporality and historical conscience – and second, the role of the entertainment industry in relation to these discussions. Concerning this last element, it will be sought to present a commentary on the articulation of the possibilities of working towards a historical education, starting from an analysis of textual and graphical narratives of games, such as Assassin's Creed Origins, developed by Ubisoft.
The temperature increase due to climate warming can affect the photosynthetic responses of aquatic macrophytes from tropical lotic ecosystems
(2023-01-01) Carriel, Orlando Aparecido ; Diagonel, Guilherme ; Boas, Lucas Kortz Vilas ; de Oliveira, Régis Campos ; Branco, Ciro Cesar Zanini ; Universidade Estadual Paulista (UNESP)
Over time, the average global temperature has varied greatly, mainly due to natural phenomena. However, several anthropic activities have caused significant changes in the Earth’s atmosphere, so that various greenhouse gases, especially CO2, have increased their atmospheric concentration and, consequently, produced an increase in the planet’s temperature. These climatic changes, particularly global warming, can affect organisms in continental aquatic environments, including primary producers (e.g., macrophytes). Using photosynthetic parameters calculated from chlorophyll a fluorescence and measurements of chlorophyll a content, we assessed the potential effects of temperature increases predicted by two future scenarios from the fifth assessment report of the Intergovernmental Panel on Climate Change (IPCC), Representative Concentration Pathway 4.5 (RCP 4.5) and Representative Concentration Pathway 8.5 (RCP 8.5), on the photosynthetic responses of five aquatic macrophytes from tropical lotic ecosystems. Our results showed a trend of a reduction in the φPSII values associated, as a rule, with an increase in the heat dissipation values in the reaction centers of photosystem II, that is, parameter E. Such reductions in the φPSII associated with increases in parameter E suggest that most likely, even the less severe RCP scenario, RCP 4.5, is already sufficient to negatively and significantly affect the photosynthetic responses of most aquatic macrophytes tested in this experimental study. Considering that macrophytes, alongside macroalgae and periphyton, form the basis of autotrophic food webs in tropical lotic ecosystems, our results suggest that there is a real possibility that the negative effects produced by global warming on these primary producers are propagated, as a “cascade effect”, indirectly affecting higher trophic levels as well.
Effects of solvent extraction on phenolic concentration and antioxidant capacity of the Oedogonium sp. (Chlorophyta) using a simplex-centroid mixture design
(2023-01-01) Tófoli, Rodolfo José ; Ferreira, Adriana Luiza ; Núñez, Eutimio Gustavo Fernández ; Haminiuk, Charles Windson Isidoro ; Branco, Ciro Cesar Zanini ; Branco, Ivanise Guilherme ; Universidade Estadual Paulista (UNESP) ; Universidade de São Paulo (USP) ; Universidade Tecnológica Federal do Paraná
Among the freshwater benthic macroalgae found in Brazilian rivers and streams, species of Oedogonium (Chlorophyta) have shown great ability to produce high biomass in several environmental conditions. Their resilience to eutrophic habitats provides an opportunity to assess the use of Oedogonium biomass for applications in different fields, especially those related to the extraction of biologically active compounds of interest for health, food, and cosmetic applications. Thus, this study assessed the effects of different organic solvents (acetone, ethanol, and methanol) and their mixtures when combined with water (20% v/v), on the extraction efficiency of total phenolic compounds (TPC), and their antioxidant capacity (AC), from Oedogonium sp. biomass, using simplex-centroid mixture design. TPC ranged from 90 to 150 mg of gallic acid equivalent per 100 g dry weight (DW), while AC ranged from 1 to 8 µM of Trolox equivalent per gram (DW). The highest TPC and AC were found for extracts using an ethanol/acetone (50:50) binary aqueous solvent mixture, while the lowest values for both TPC and AC were found for the methanolic aqueous solvent. Considering the relatively low-cost and less adverse environmental impacts of the ethanol and acetone aqueous mixture, our results suggest that the use of this specific mixture of organic solvents may have significant advantages in an eventual industrial process for the extraction of phenolic compounds from Oedogonium species.
Dynamic analysis of an electromagnetic vibration absorber in a non-ideal system
(2023-01-01) Petrocino, Eduardo Abuhamad ; Balthazar, José Manoel ; Tusset, Ângelo Marcelo ; Gonçalves, Paulo José Paupitz ; Silveira, Marcos ; Universidade Estadual Paulista (UNESP) ; Federal University of Technology – Paraná
A dynamic system usually used in engineering are rotating machines fixed to flexible structures, and an excessive vibration known as the Sommerfeld effect may occur in the passage of the resonance. This research aims to analyze an electromagnetic absorber in a non-ideal system, a simple model for the analysis of the first mode of a beam. In this context, an investigation of the dynamic behavior of a cantilever beam with a dc motor coupled to its free end, having an unbalanced mass on its axis, providing a non-ideal energy source. A permanent magnet is attached to this same free end, which is immersed inside a coil attached to the base. In this step, an analysis of the dynamic behavior is carried out by means of an analytical solution approximated by the averaging method and by numerical computational simulations. The absorber reduces the phenomena caused by the Sommerfeld effect and reduces the region of instability.
Analysis of the dynamic characteristics of rod and beam structures with nonlinear stiffness boundaries
(2022-07-01) Xu, Wenfeng ; Tang, Bin ; Brennan, Michael J. ; Manconi, Elisabetta ; Gonçalves, Paulo J. Paupitz ; Dalian University of Technology ; Universidade Estadual Paulista (UNESP) ; University of Parma
Nonlinear boundaries exist in many engineering structures and significantly influence the vibration of systems. The dynamic characteristics of a rod or beam structure with nonlinear stiffness boundaries were studied. The traveling wave method and the variable separation method were used to analyze the dynamic characteristics of the rod, and the relationship between the two approaches was investigated. For the beam, the incident propagating and nearfield waves were considered, respectively. The relationships between the dimensionless frequency, displacement, reflection coefficient, and phase were discussed by using the harmonic balance method. Finally, the backbone and frequency response curves of the rod and beam structures were obtained by using the phase closure principle and the variable separation method. In order to verify the accuracy and effectiveness of the theoretical calculations, a finite element numerical simulation was carried out for the rod and beam models. The results show that the theoretical solutions compare well with the numerical simulation results.
On the Formation of a Super Attenuation Band in a Mono-coupled Finite Periodic Structure Comprising Asymmetric Cells
(2023-01-01) Germanos Cleante, Vinicius ; Brennan, Michael John ; Paupitz Gonçalves, Paulo José ; Carneiro, Jean Paulo ; Universidade Estadual Paulista (UNESP)
Metamaterials are employed to reduce vibration levels by exploiting the effects of structural periodicity. When structural elements are arranged in a periodic pattern, they act as mechanical filters, creating stop-bands. The term stop-band is often used for infinite structures, but a more appropriate term for a finite structure is attenuation band. A way of obtaining this effect is by attaching vibration absorbers, which create a local resonance stop-band plus a Bragg stop-band. The local resonance stop-band is controlled only by the properties of the attached device. The Bragg stop-band depends on the interaction between the host cell and the device. The combination of these two effects can create an attenuation zone – the so-called super attenuation band. Recent works on finite mono-coupled metamaterials have shown that asymmetric periodic structures have better attenuation properties when compared to the symmetric ones, if they are correctly orientated. This paper investigates the formation of a super attenuation band in a finite mono-coupled structure using vibration absorbers. The system is defined by the formation of a cell, which repeats along with the whole structure. The cell can be divided into sub-cells with equal or different dynamic properties. The dynamic features to form the super attenuation band are determined from the displacement transmissibility of a single cell. This analysis is extended to several cells. The results show that a super attenuation band can only occur when each attached vibration absorber is optimally tuned to its corresponding host cell in a structure comprising cells with dynamical asymmetry.
Climate warming effects on photosynthetic responses of tropical stream macroalgae
(2022-01-01) Boas, Lucas Kortz Vilas ; Oliveira, Régis de Campos ; Branco, Ciro Cesar Zanini ; Universidade Estadual Paulista (UNESP)
The increase in Earth’s global mean temperature due to anthropogenic climate change threatens many ecosystems. Freshwater ecosystems present characteristics that put their biodiversity at an even greater risk. In low-order tropical streams, benthic organisms contribute to a large fraction of the community energy input from primary producers and play a significant role in sustaining autotrophic food webs. Using the chlorophyll fluorescence and dissolved oxygen evolution techniques, we carried out a laboratory experiment to evaluate the effects of projected temperature increases due to global warming of two future scenarios (Representative Concentration Pathway [RCP] 4.5 and RCP 8.5) proposed by the Intergovernmental Panel on Climate Change (IPCC) on the photosynthetic response of lotic macroalgae. We determined control temperatures in both the summer and winter by taking measurements directly in the field, and we calculated experimental scenario temperatures by adding the projected IPCC increases to the seasonal means. Although there were species-specific responses to the simulated scenarios, we noted some trends. In general, the tested Rhodophyta species showed weakened photosynthetic per-formance, particularly in the highest IPCC-predicted scenario (RCP 8.5). In addition, the temperature increase of the IPCC projected scenarios did not produce significant negative effects on the photosynthesis of most Charophyta and Chlorophyta species, revealing a tolerance of these algae to the tested temperature variations. In some cases, most notably Spirogyra sp., there was an increase in the photosynthetic performance. Given the position of these organisms at the base of the food web, our results indicate that fulfillment of the IPCC scenarios could markedly impact tropical lotic environments, especially in shaded low-order streams, where Rhodophyta constitute a highly relevant group of primary producers.
A Sustainable Raw Material for Phytocosmetics: The Pulp Residue from the Caryocar brasiliense Oil Extraction
(2022-10-01) Pegorin Brasil, Giovana Sant’Ana ; Borges, Felipe Azevedo ; Machado, Amanda de Andrade ; Mayer, Cassia Roberta Malacrida ; Udulutsch, Renata Giassi ; Herculano, Rondinelli Donizetti ; Funari, Cristiano Soleo ; dos Santos, André Gonzaga ; Santos, Lucinéia ; Universidade Estadual Paulista (UNESP)
Agroindustrial residues have great potential to improve sustainable production and generate high value-added chemical products. The Cerrado is considered the most threatened biome in Brazil, which houses 4600 endemic species, such as Caryocar brasiliense Cambess., Caryocaraceae. Its fruit, popularly known as “pequi,” is used in regional culinary, in the treatment of diseases, and its consumed portion corresponds to only 10% of its weight. In this work, a “pequi” pulp residue extract was prepared and incorporated in a cosmetic formulation. Both were chemically characterized, and their antioxidant and sun protection factor activities were assessed, as well as the in vitro toxicity in red blood cells and fibroblasts. The extract and the phytocosmetic presented high levels of phenolic compounds, which were identified by liquid chromatography, and showed antioxidant and photoprotective activities that can be justified by the presence of well-known antioxidant compounds. In toxicological tests, both samples exhibited low toxicity in the hemolysis assay (rates < 5%) and low cytotoxicity (viability > 100%). Thus, the extract from C. brasiliense pulp residue presents great potential to be explored in the development of cosmetic products. Graphical abstract: [Figure not available: see fulltext.]
A passive self-tuning vibration neutraliser using nonlinear coupling between the degrees of freedom
(2023-02-15) Nehemy, Gabriella Furlan ; Rustighi, Emiliano ; Gonçalves, Paulo J. Paupitz ; Brennan, Michael J. ; Universidade Estadual Paulista (UNESP) ; University of Trento
Vibration neutralisers are widely used to suppress vibration of a host structure subject to external excitation at a specific frequency. When attached to a structure, they create a notch filter in the frequency response, reducing the vibration levels considerably. An inherent limitation is related to the narrow frequency range in which they are effective. Over the years, there have been different attempts to make the vibration absorber more robust. These include using active and semi-active control strategies to change the tuning frequency, using piezoelectric elements with shunt circuits, electromagnetic actuators, servo motors, and even exploring nonlinear effects. In many cases, there is a need for an external power source to modify the characteristics of the system. This paper concerns a passive vibration neutraliser that can adapt automatically to one of two frequencies corresponding to the frequency of an external harmonic force. Importantly, it does this without the need for an external power source. The device consists of a beam-like neutraliser that is attached to the host structure at its centre through a roller bearing. The stiffness element is a rectangular beam that can rotate in the bearing, changing the stiffness it presents to the direction of excitation. The paper describes an experimental study into such a device, and an analytical model is proposed that qualitatively captures the time-domain behaviour of the experimental device. A possible mechanism by which the device self-tunes to either of the two frequencies of excitation is discussed. Supplementary material is also provided to show the device in operation.

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