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Análise multivariada de conteúdos da cultura científica via ciência de dados sociais e aprendizado de máquina RAG-LLM (geração aumentada por recuperação para modelos linguísticos de grande dimensão)
(Universidade Federal de São Carlos, 2025-03-28)
Terezan de Moura, Renato Aparecido
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Sousa, Cidoval Morais de
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https://lattes.cnpq.br/0573233540937425
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https://orcid.org/0000-0002-7812-8667
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https://lattes.cnpq.br/9976994758941814
Guided by interdisciplinary epistemological approaches from the field of Science, Technology, and Society (CTS), we investigated communication dynamics in two projects at a public university, using a hybrid approach that combines Content Analysis with Machine Learning and Social Data Science. We collected and analyzed collections from websites and digital media, including interactions in chats, comments, and event broadcasts. Our research demonstrated the effectiveness of scientific culture dynamics, the public reach of the projects, and revealed user idiosyncrasies through the correlation of quantitative and qualitative variables. The data was collected and mined using statistical and Natural Language Processing (NLP) techniques in MAXQDA software, and complemented by multivariate analyses. To analyze audiovisual and textual content from streaming channels, we developed machine learning pipelines with RAGs-LLMs (Retrieval-Augmented Generation for Large Language Models). The results of the thesis are presented in visual and analytical dashboards on the website tecnociencia.net.br, where we also implemented a conversational robot (Tesebot), trained with the research content to answer questions. The conclusion of the thesis shows that its corroboration is inevitable and loaded with statistical and inferential certainties, which reflect and legitimize the complexity of research in the era of post-academic science, big tech, social networks, and artificial intelligence. The methodological strategies made it possible to understand all the variables and statistical and relational instances involved in the dynamic observation of scientific culture in the dissemination projects researched.
Produção de nanoestruturas de carbono para bioaplicações
(Universidade Federal de São Carlos, 2025-03-28)
Almeida, Larissa Solano de
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Viana Neto, Bartolomeu Cruz
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https://lattes.cnpq.br/2504557482950231
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https://orcid.org/0000-0002-5207-4269
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Rossino, Luciana Sgarbi
Carbon nanotubes (CNTs) stand out in research due to their attractive chemical and physical properties, which are influenced by the high quality of these nanostructures and allow their application in several areas. The quality of CNTs is directly related to growth parameters, such as gas flow, voltage, time, and temperature. Conventional techniques, such as chemical vapor deposition (CVD), produce carbon nanostructures with fewer defects but require high temperatures, reaching 1000 °C. A promising alternative is plasma-assisted chemical vapor deposition (PECVD), capable of producing CNTs at temperatures close to 450 °C. This work aimed to obtain CNTs through the PECVD technique with a pulsed DC source. The growth was performed on a nickel substrate, using Ar/H₂/CH₄ gases, with a voltage of 500 to 800 V, temperature of approximately 450 °C, and treatment times ranging from 5 to 30 minutes. The discovered nanostructures were recorded by Raman spectroscopy, SEM, TEM, XPS, fixed-sphere wear test, UV-Vis scattering test, and cytotoxicity and toxicity tests in terrestrial and aquatic environments. The Raman spectra revealed bands characteristic of carbon-based materials, such as D, G, D’, 2D, and D+G. For effective growth, the plasma needed to have sufficient energy, and the SEM micrographs confirmed the effective formation of CNTs at resistances above 700 V. The growth time directly influenced the quantity and quality of CNTs, with greater production observed in periods longer than 15 minutes. The diameter of the CNTs increased with the increase in the total gas flow. The results indicated the delivery of multi-walled carbon nanotubes (MWCNTs), with the presence of defects, which may be advantageous depending on the application. The optimized growth settings were: flow rate of 235 sccm, voltage of 800 V, and time of 30 minutes, producing MWCNTs effectively. Furthermore, with the optimized settings, it was possible to evaluate the incorporation of nitrogen on the surface of the CNTs. The results demonstrated that the increase in the nitrogen flow caused greater structural disorder, indicating its incorporation. The CNTs presented greater dispersivity in an aqueous medium compared to CNTs with nitrogen and commercial CNTs. Furthermore, the CNTs demonstrated lower toxicity in biological, terrestrial, and aquatic systems, being promising for bioapplications. As a second work proposal, the production of a CNTs/DLC hybrid carbon nanostructure was carried out, evaluating its tribological potential. The material presented wear resistance, showing significant potential due to the synergy between the properties of CNTs and DLC films. However, further studies and characterization techniques are needed to validate these results. Thus, the work highlights the importance of optimizing growth parameters to obtain quality and quantity of CNTs at low temperatures using the PECVD technique.
Desenvolvimento e validação de método analítico para determinação de nutrientes e contaminantes em pescados do baixo rio São Francisco utilizando técnicas de plasma
(Universidade Federal de São Carlos, 2025-03-28)
Silva, Lorena Lima da
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Nogueira, Ana Rita de Araújo
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https://lattes.cnpq.br/7034773971317045
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https://orcid.org/0000-0003-3648-2956
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https://lattes.cnpq.br/1923563841127712
DEVELOPMENT AND VALIDATION OF AN ANALYTICAL METHOD FOR DETERMINING NUTRIENTS AND CONTAMINANTS IN FISH FROM THE LOWER SÃO FRANCISCO RIVER USING PLASMA TECHNIQUES. The Lower São Francisco (BSF) region, which includes areas of Alagoas, Sergipe, Bahia, and Pernambuco, plays an essential role in socioeconomic development and the preservation of local culture. However, the impacts arising from human activities can cause the bioaccumulation of harmful substances, such as potentially toxic elements, in aquatic organisms and biomagnification along the food chain. Monitoring water parameters of ichthyofauna and flora is essential to assess environmental impacts, identify reliable bioindicators, ensure food security, and support sustainable management policies. This study developed and validated an analytical methodology suitable for the determination of nutrients and inorganic contaminants in fish collected in the BSF by microwave-induced plasma optical emission spectrometry (MIP OES) and inductively coupled plasma mass spectrometry (ICP-MS). The optimal digestion and determination conditions were established, which included the determination of the limits of detection (LOD), quantification (LOQ), linearity, precision, and accuracy, using certified reference materials and addition and recovery assays. Iron, Zn, Cr, Cu, V, Ni, Co, Mo, Mn, Se, Sr, As, Cd, Hg, and P were determined by ICP-MS and Ca, K, Mg and P by MIP OES in 136 samples collected in two stations, over 12 months. The Pb, Ni, Mo, Cd, Cr, Co, and V levels were < LOD in all samples evaluated. For the summer, the determined contents indicated the following variations: Ca (0.1−2.8 g kg⁻¹), K (1−8 g kg⁻¹), Mg (0.1−0.6 g kg⁻¹), P (0.6−5 g kg⁻¹), Fe (0.7−15 mg kg⁻¹), Zn (0.9−12 mg kg⁻¹), Se (0.1−0.6 mg kg⁻¹), Sr (0.1−5 mg kg⁻¹), Cu (0.1−9.2 mg kg⁻¹), Mn (0.1−2 mg kg⁻¹) and As (0.1−5 mg kg⁻¹). For winter, Ca (0.1−2 g kg⁻¹), K (1−7 g kg⁻¹), Mg (0.2−0.4 g kg⁻¹), P (0.5−5 g kg⁻¹), Fe (0.3−10 mg kg⁻¹), Zn (0.4−20 mg kg⁻¹), Se (0.1−0.6 mg kg⁻¹), Sr (0.1−6 mg kg⁻¹), Mn (0.1−3 mg kg⁻¹), As (0.1−4 mg kg⁻¹) and Cu (0.1−0.3 mg kg⁻¹). For the first time, the mineral profile of BSF fish was obtained, indicating satisfactory nutrient levels per the daily consumption recommendations and contaminants below the limits established by legislation.
Análise funcional da atenção compartilhada em bebês com deficiência visual: uma replicação
(Universidade Federal de São Carlos, 2025-03-28)
Silva, Thalissa Cazarine da
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Gil, Maria Stella Coutinho de Alcântara
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https://lattes.cnpq.br/1673770301699940
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https://orcid.org/0000-0003-4375-3232
;
Latina
Joint Attention (JA) is a triadic process essential for child development, involving the coordination of attention between the infant, an adult, and an event or object. Although traditionally associated with behaviors such as eye contact and pointing, this model becomes limited when applied to infants with visual impairments (VI), who may develop alternative forms of social and cognitive engagement. Despite its relevance, there is a scarcity of studies that examine JA from a behavior-analytic perspective, especially in the context of VI. This study aimed to conduct a descriptive functional analysis of the contingencies that support JA in dyads composed of a sighted adult and a child with VI, aged between 10 and 36 months. Interactions were video-recorded in a structured environment using tasks adapted from the Early Social Communication Scales (ESCS). Video logging enabled the identification of discriminative stimuli, dyadic responses, and the consequences that maintained episodes of JA. Results showed that the adult’s Requesting Speech (RS) and Descriptive Speech (DS) functioned as effective discriminative stimuli for evoking JA responses in infants. Additionally, auditory and luminous stimuli significantly increased the frequency of JA episodes, whereas tasks relying solely on distant visual stimuli led to reduced engagement. The physical proximity of the stimulus also favored the occurrence of JA, although the presence of auditory cues proved more decisive in regulating infant responsivity. Another key finding was the predominance of adult-initiated JA attempts (IJA), which were not always followed by infant responses (RJA). This highlights the need for a contingent and temporally contiguous relationship between IJA and RJA to configure a functional episode of joint attention. These findings offer valuable insights for educational and intervention strategies in the field of Special Education, helping professionals and families foster more responsive and functional interactions. It is recommended that future research develop teaching procedures to expand the IJA and RJA repertoires of infants with VI, as well as parental training programs aimed at enhancing caregivers’ sensitivity in mediating access to discriminative stimuli. The results of this study suggest that infants with visual impairments can learn to engage in joint attention, provided that social interactions are designed in accordance with their sensory limitations and developmental potential.
Impactos de complexos de rutênio (II) em diferentes abordagens da agregação do peptídeo beta amiloide
(Universidade Federal de São Carlos, 2025-03-28)
Tiburcio, Marco Antonio
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Carlos, Rose Maria
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https://lattes.cnpq.br/1589143355309943
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https://orcid.org/0000-0002-0277-9789
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https://lattes.cnpq.br/0990167626370741
Alzheimer's Disease is the most common form of dementia, with projected costs of $1 trillion by 2030. Its main features include deposits of the Aβ peptide and neurofibrillary tangles of the tau protein. Increased life expectancy is linked to the rising incidence of the disease, creating significant social and financial impacts. This study aims to evaluate the effects of Ru(II) complexes as modulators of Aβ aggregation in different approaches, from heterogeneous aggregation with insulin to in vivo applications. The modulating effect of the RuApy complex on cross-aggregation between Aβ and insulin was monitored through Tyr10 emission, circular dichroism (CD), and AFM. Emission spectra for Aβ showed suppression of Tyr-OH emission (300 nm) in favor of Tyr-O¯ ion formation (340 nm), a behavior not observed in the presence of insulin and the RuApy complex. CD and AFM analyses revealed the formation of amorphous aggregates instead of the fibrils typically seen with Aβ. The aggregates formed in the Aβ/Insulin and Aβ/Insulin/RuApy interactions were less toxic compared to Aβ aggregates when tested on SH-SY5Y neuroblastoma cells. In another approach, the influence of the RuNDI complex on Aβ aggregation was monitored by nephelometry, CD, and TEM. The presence of the RuNDI complex significantly reduced relative nephelometry units and suppressed β-sheet signals in CD spectra, indicating reduced aggregate formation. TEM images revealed the formation of amorphous aggregates. The effects of the RuNDI complex on Aβ aggregation were also evaluated in APP/PS1 mice, a model for Alzheimer's Disease. These animals develop Aβ deposits in the cortex and hippocampus after 16 weeks of age. The complex was administered intraperitoneally at daily doses of 1 mg/kg for 10 weeks. Amyloid deposition was monitored in real-time using multiphoton microscopy. ELISA and immunofluorescence assays were performed on blood and cortex samples at the end of the experiments. Although real-time disease progression could not be assessed, lower levels of Aβ40/42 were observed in cortex samples from treated mice. Immunofluorescence using ThS and 4G8 showed that the RuNDI complex did not affect the size of existing plaques but significantly reduced plaque density and load in the cortex and hippocampus. These observations demonstrate that the RuApy and RuNDI complexes directly impact Aβ fibrillation in different approaches, leading to the formation of amorphous and non-toxic fibrils and reducing the formation of deposits in critical brain areas of transgenic mice.
Efeitos do exercício físico na destreza manual, sintomas motores e plasticidade cerebral em indivíduos com doença de Parkinson
(Universidade Federal de São Carlos, 2025-03-28)
Menacho, Maryela Oliveira
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Gianlorenço, Anna Carolyna Lepesteur
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Fregni, Felipe
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https://lattes.cnpq.br/3861050459671690
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https://lattes.cnpq.br/7140517621736868
Parkinson’s disease is the second most common progressive neurodegenerative disorder and is characterized by symptoms such as resting tremor, bradykinesia, rigidity, and postural instability, which significantly affect upper limb function in patients. Physical exercise is a non-pharmacological intervention alternative for these patients, as it can contribute significantly to improving quality of life. Therefore, this thesis was divided into two studies. The first aimed to gather the available literature on the effects of physical exercise on upper limb function in individuals with Parkinson’s disease through a systematic review. A systematic search was conducted using the PubMed, Embase, CENTRAL, PEDro, Scopus, and Web of Science databases, including the following terms: Parkinson’s disease, exercise/physical therapy, upper limb, and their respective entry terms. These terms were combined using Boolean operators (AND/OR) according to each database. A total of 15 randomized controlled trials were included, which performed the following interventions: task-oriented training, virtual reality/game therapy, training of activities of daily living, robotic therapy, training with a musical instrument, eccentric strengthening, constraint-induced movement therapy, manual dexterity training, and exercises with therapeutic mass. In conclusion, activity-based training is a viable option to improve manual dexterity in individuals with Parkinson’s disease. The second study was a randomized controlled clinical trial aimed at evaluating and comparing the effects of different physical intervention modalities—aerobic training, resistance training, and task specific training on motor symptoms, manual dexterity, and brain oscillatory activity in individuals with Parkinson’s disease. Thirty-seven participants, with a mean age of 62 years and presenting upper limb functional deficits, completed the study. Participants were randomized into four groups: aerobic training (AT), resistance training (RT), task specific training (TT), and control group (CG). The AT group performed 30 minutes of upper limb cycling using a portable cycle ergometer at an intensity of 50–70% of heart rate reserve. The RT group performed two sets of 8 to 12 repetitions for each exercise, with a two-minute rest between sets, at an intensity of 50–70% of one-repetition maximum (1-RM), determined by the 1-RM test. Free weights and an upper limb exercise machine were used for the resistance exercises. The TT group performed three activities aimed at improving reach, grasp, and manipulation for 30 minutes. All intervention sessions were conducted three times per week for eight weeks. Motor symptoms were assessed using part III of the Unified Parkinson’s Disease Rating Scale (UPDRS-III). Manual dexterity was evaluated using the Nine-Hole Peg Test, and quantitative electroencephalography (qEEG) was used to assess brain activity. Two-way ANOVA and the Scheirer–Ray–Hare test were used to evaluate the effects of time and group on clinical variables, and group and brain region on EEG band power. The level of statistical significance was set at 5%. There was a significant main effect of time (F = 2.80; p = 0.05) and group (F = 2.94; p = 0.03) on the UPDRS-III, with no significant interaction between the factors (F = 1.46; p = 0.23). Tukey's post hoc test showed significant differences in the aerobic (p = 0.04) and resistance training groups (p = 0.04) compared to the control group. No significant group (F = 0.54; p = 0.70) or time effect (F = 0.87; p = 0.35) was observed in the Nine-Hole Peg Test. Additionally, the interventions had a significant effect on the low-alpha sub-band (F = 4.85; p = 0.003) and the alpha band (F = 5.10; p = 0.003), regardless of brain region, in the task specific training group compared to the control group (p = 0.001). For the beta band and low-beta sub-band, there was a main effect of the interventions (F = 5.56; p = 0.001) and (F = 7.59; p < 0.001), with no effect of brain region and no interaction between factors. Tukey's post hoc analysis revealed a significant difference in low-beta in the task specific training group compared to the control group (p < 0.001), and in beta for the resistance training (p = 0.007), aerobic training (p = 0.008), and task specific training (p = 0.004) groups compared to the control group. In conclusion, task specific training based on activities of daily living significantly improved motor symptoms and reduced alpha, low-alpha and low-beta spectral power in individuals with Parkinson’s disease. Furthermore, all interventions caused a significant reduction in beta spectral power, with no difference between them and regardless of brain region. Therefore, the studies presented in this thesis support the importance of physical exercise as a non-pharmacological strategy within the therapeutic plan for this population. In the systematic review, the meta-analysis showed a significant effect of activity-based training on fine manual dexterity compared to other active interventions, while the clinical trial demonstrated a significant improvement in motor symptoms among those who received either aerobic or resistance training. Finally, all proposed interventions resulted in significant changes in brain oscillatory activity.
Análise multidimensional dos componentes edáfico e arbóreo em sistemas integrados de produção
(Universidade Federal de São Carlos, 2025-03-28)
Fernandes, Pedro Henrique de Godoy
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Bernardi, Alberto Carlos de Campos
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https://lattes.cnpq.br/5588269274851789
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Tanaka, Marcel Okamoto
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https://lattes.cnpq.br/2768658925977757
The increasing global demand for food drives deforestation of natural areas, converting them into agricultural and livestock production systems, thereby increasing greenhouse gas (GHG) emissions and accelerating ongoing climate change. Therefore, production models that reconcile food production with environmental conservation need to be implemented. This study evaluated integrated crop-livestock-forestry (ICLF) and livestock-forestry (ILF) systems, as well as forest restoration, as land use strategies to improve improve soil chemical and physical parameters and mitigate GHG emissions. Additionally, a methodology for monitoring forest metrics through remote sensing was assessed. The first chapter evaluated the physical and chemical attributes of soil in ICLF, ILF, forest restoration, degraded pasture, and forest remnants. We observed that systems incorporating a tree component improved soil quality by increasing organic matter (OM), cation exchange capacity (CEC), carbon content (C), and reducing soil bulk density. In the second chapter, we analyzed forest structure, as well as soil and aboveground biomass (AGB) carbon stocks, in areas under ICLF, ILF, forest restoration, and forest remnants. Integrated systems exhibited larger trees with lower stratification, whereas restoration and forest remnants showed higher tree density, greater stratification, and higher basal area. AGB C stocks were similar across areas, except for ICLF-N and ICLF-G. Forest remnants and ILF systems had the highest soil carbon stocks. Total C stocks were comparable among ILF, restoration, and forest remnants, with approximately 60% stored in the soil and 40% in AGB. The third chapter involved the validation of remotely piloted aircraft (RPA) and digital aerial photogrammetry (DAP) for estimating forest metrics. Field data on diameter at breast height (DBH), tree height, basal area, tree density, and AGB were compared with three-dimensional models generated from orthomosaics and point clouds, using multiple linear regression models. After model selection, we spatialized the variables of interest across the entire study area. The digital terrain model accurately represented the area's topography, contributing to model quality. The predictive model for DBH showed the lowest R² along with the lowest RMSE, while the height model performed slightly better. Basal area and tree density yielded similar results. The predictive model for AGB demonstrated satisfactory R² and RMSE values for estimating AGB and forest metrics. Therefore, integrated production systems contribute to soil quality and C stocks. Systems such as ICLF and ILF, along with forest restoration, are capable of sequestering amounts of C from AGB comparable to those in forest remnants, making them effective strategies for GHG’s emission mitigation. Lastly, we found that DAP-related methods can be applied in integrated production systems, facilitating better access to carbon stock estimates and monitoring for rural producers.
Modificação estrutural do Nb2O5 para aplicação em processos de remediação ambiental
(Universidade Federal de São Carlos, 2025-03-28)
Rodrigues, Thaís Aparecida
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Mendonça, Vagner Romito de
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https://lattes.cnpq.br/4270375873948823
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https://lattes.cnpq.br/3891783906198938
Brazil holds 98 % of the world’s niobium deposits, making it essential to add scientific and economic value to this material. This study investigated the modification of niobium pentoxide with other oxides, specifically vanadium pentoxide and tungsten trioxide, using the oxidative peroxide method followed by hydrothermal treatment, to enhance its photocatalytic and adsorptive properties for environmental remediation applications. The synthesized samples were characterized using X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), N2 physisorption-desorption, and zeta potential analysis. The photocatalytic and adsorptive properties were evaluated through the photodegradation and adsorption of dyes Methylene Blue (MB) and Rhodamine B (RhB), the pharmaceutical Amiloride (AML), and the CO2 photoreduction process. For the vanadium-based modification, ammonium niobium oxalate (ANO) was used as a precursor. However, due to changes observed in the material over time, the experiments were conducted in two separate stages, using ANO from the 2017 and 2022 batches. In both cases, the analyses confirmed the doping of Nb2O5 with vanadium. Under the first condition (2017 batch), the doped sample exhibited excellent performance in the photodegradation of RhB and AML compared to isolated Nb2O5. In the CO2 photoreduction tests, the vanadium-modified sample favored CO formation over H2, suggesting that the modification enhanced CO2 adsorption on the material’s surface. Under the second condition (2022 batch), the modification improved the adsorptive properties of MB. Adsorption studies indicated that the primary adsorption mechanism was physisorption, and the sample maintained its efficiency over five consecutive cycles. For the modification of Nb2O5 with WO3, the optimal condition was achieved using ammonium niobium oxalate and tungstic acid, with a molar ratio of 80% WO3 to Nb2O5. The analyses confirmed the formation of a heterostructure. In the photodegradation tests, the heterostructure exhibited combined properties of both oxides, as bare Nb2O5 and WO3 were more effective in decolorizing MB and RhB, respectively. However, the heterojunction was capable of both adsorbing and photodegrading both dyes. The results indicate that modifying Nb2O5 with vanadium and tungsten compounds enhanced its photocatalytic and adsorptive properties, making these materials promising for environmental remediation applications.
Direito à água: contribuições para o acesso mais justo, equitativo e democrático à água
(Universidade Federal de São Carlos, 2025-03-31)
Moraes, Tatiana Vieira de
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Oliveira, Celso Maran de
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https://lattes.cnpq.br/9911833172043700
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https://orcid.org/0000-0002-6442-3614
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https://lattes.cnpq.br/3999527499047171
Water in quantity and quality is an essential human right, but a large portion of the population still does not have access to this right. SDG 6 sets the goal of universal and equitable access to water for all people by 2030 and, based on the hypothesis that the current Brazilian water management system does not sufficiently guarantee access to the right to water in an equitable and fair manner, this study aims to identify, based on case studies of water conflicts, various possibilities and potential actions, measures or principles with a view to contributing to fairer, more equitable and democratic access to the right to water. To this end, methodological pluralism was adopted, with each chapter addressing a set of specific methods and procedures. The study is presented in three parts: the first, more theoretical, proposes a literature review. At this point, the right to access water as an essential human right is discussed, pointing out the possibility of considering water as a fundamental right in Brazil, even without express constitutional provision. It also analyzes the Brazilian National Water Resources Policy and criticizes the conventional model of water resources management adopted in Brazil, especially its limitations in terms of participation and equity. This is followed by a discussion of effective water governance, highlighting the importance of a governance system that strengthens the participation of society. This part of the study concludes with theoretical clarifications on the concept of water equity, presenting definitions and basic elements, as well as differentiating equity from water justice. The second part examines case studies of water problems/conflicts. Adopting a narrow geographical approach, a survey was carried out of cases of international and national water conflicts in the literature; in the state of São Paulo through Civil Inquiries by the Public Prosecutor’s Office of São Paulo (MPSP); and a local case in the municipality of São Carlos/SP. The results of this part of the study were the mapping of water conflicts based on the cases examined and the potential of the measures and solutions suggested and/or applied to resolve or mitigate the conflicts. The third part of the study is propositional, presenting contributions to more equitable and democratic access to the right to water and interconnecting the first two parts. The analyses of the previous parts of the study demonstrate the existence of various inequalities in access to water and the inadequacy of the conventional water management system to sufficiently guarantee fair, democratic and equitable access to the right to water. As a result, contributory proposals were generated aimed at advancing the transition from the current water management format to a more effective system of ‘good water governance’ that promotes democratic, equitable and fair access to the right to water.
Fusão em leito de pó a laser de aço ferramenta A2: efeito de parâmetros de processo, tratamentos térmicos e adição de Cr₃C₂
(Universidade Federal de São Carlos, 2025-03-31)
Bianchini, Bruno
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Gargarella, Piter
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https://lattes.cnpq.br/4641435644243916
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https://orcid.org/0000-0003-4445-5819
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https://lattes.cnpq.br/8443988120967281
Tool steels have strict requirements for composition, processing and mechanical properties, and are utilized in fabrication of molds or tools employed in the processing of other materials. In many cases, they are expensive and of difficult machinability, which opens up the possibility for alternative processing routes such as additive manufacturing (AM) by Laser Powder Bed Fusion (L-PBF), which allows fabrication of parts with complex sections, such as internal cooling channels, without additional processing cost and with minimal need for post-processing, due to its great dimensional accuracy. However, the severe conditions to which the L-PBF process submits materials induce the formation of a highly refined microstructure, and possibly defects. This work studies the possibility of manufacturing AISI A2 tool steel by L-PBF, considering the effect of process parameters and post-processing in its microstructure and properties, and the modification of this material for defect mitigation. Results showed that, despite it being possible to determine a processing window for minimal porosity, the material composition and the severe processing conditions cause the formation of cracks, mostly during solidification. The as-built microstructure is, similarly to other tool steels manufactured by L-PBF, composed of martensite cells surrounded by retained austenite, while the formation of primary carbides is suppressed. After heat treatment, the formation of secondary carbides was found to be also in low quantity, showing that temperings without prior austenitization would need higher temperatures or longer times to cause significant effects on the microstructure and mechanical properties. Finally, it was discovered that the addition of Cr3C2 chromium carbide by mechanical mixture, at a fraction of 5%, was capable of mitigating defect formation by altering the alloy composition, when manufactured by L-PBF.
Feijão guandu para uso alimentar: composição química, funcionalidade e aspectos nutricionais
(Universidade Federal de São Carlos, 2025-03-31)
Tozo, Marcelo Larsen de Lima
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Rita de Araujo Nogueira, Ana
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https://lattes.cnpq.br/7034773971317045
;
https://orcid.org/0000-0003-3648-2956
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https://lattes.cnpq.br/6205481423806854
This dissertation aims to develop and apply analytical procedures to evaluate the total levels, bioaccessibility, and bioavailability of essential elements and total proteins in two pigeon pea (Cajanus cajan (L.) Millsp) varieties previously selected for human consumption. Raw and cooked samples were evaluated at different stages of maturation, as well as commercial varieties of common beans (carioca and black). Bioaccessibility and bioavailability were obtained after in vitro gastrointestinal digestion simulations and bioassays with Caco-2 cells. For proteins, the total fraction and the bioaccessible fraction were quantified by combustion (Dumas), and free amino acids by high-performance liquid chromatography (HPLC). The macro and micronutrients evaluated, Ca, Mg, P, Cu, Fe, and Zn, were determined by inductively coupled plasma optical emission spectrometry and mass spectrometry (ICP OES and ICP-MS), after microwave-assisted decomposition using diluted acid (7.0 mol L-1), both for total contents and for bioaccessible and bioavailable fractions. The bioaccessibility of elements varied from 0.8 to 19% for Ca and from 48 to 67% for Cu. Bioaccessibility of Ca, Fe, Mg, and Zn decreased with bean maturation. Finally, an in vitro intestinal simulation with Caco-2 cells, aimed at estimating nutrient bioavailability, faced issues with the integrity of the cell monolayer, making it impossible to estimate bioavailability values. However, the results obtained suggest the direction to be followed for improving this experiment and obtaining reliable results. Regarding crude protein content, pigeon pea samples were close to 20%. For amino acids, amounts ≥ 1% of glutamic acid, aspartic acid, and leucine were found. For the mature grain, lysine and phenylalanine were present in amounts ≥ 1%, compared to the green grain. However, in the mature grain, the amounts of glycine, histidine, threonine, alanine, and tyrosine were low (≤ 0.4%), and no methionine, cystine, or taurine were detected in either grain. The protein bioaccessibility varied between 16.4% and 19.4%. There was an increase in the total protein content with the maturation of the beans, while the bioaccessible percentage remained unchanged. For the recommended daily intake (RDI), the consumption of 100 g of cooked food suggests that the pigeon pea may be an alternative source of nutrients, highlighting Mg and P, although its contribution is lower compared to the commercial varieties of carioca and black beans. Additionally, all the beans studied show potential for protein supplementation, ranging from 32.8 – 38.8% of the RDI, reinforcing the importance of these legumes and others in human nutrition.This study is significant from a nutritional perspective, providing unprecedented data on the nutritional aspects of two varieties of pigeon peas and the bioaccessibility of essential elements, indicating their use as a consumption alternative.
Modelagem multiescala e validação experimental da dinâmica interfacial em sistemas de eletrólise da água: explorando fenômenos locais inerentes das reações eletroquímicas
(Universidade Federal de São Carlos, 2025-03-31)
Leite, Gabriel Wosiak
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Souza, Ernesto Chaves Pereira de
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https://lattes.cnpq.br/1505400360366643
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https://orcid.org/0000-0003-1058-302X
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https://lattes.cnpq.br/8033550667466489
This thesis addresses the efficiency challenges in hydrogen production via water electrolysis, focusing on the coupled effects of gas bubble evolution and interfacial pH variations during alkaline electrolysis. Multiscale computational models were developed, combining the Finite Element Method (FEM) and Computational Fluid Dynamics (CFD) to simulate bubble dynamics and interfacial pH distribution, with experimental validation using filming techniques and chronopotentiometric analysis to explore energy consumption during electrolysis. The results showed that pulsed-current operation can mitigate local pH variations; however, maintaining stable pH conditions under high current densities remains a challenge. Additionally, an asymmetric electrolysis cell configuration was proposed and validated, demonstrating a reduction in local pH gradients and up to a 17% improvement in electrolysis efficiency. This work opens new perspectives for developing more efficient electrolyzers, contributing to sustainable and economically viable hydrogen production.
Como a alfabetização científica se desenvolve no contexto da educação básica: um olhar sobre a prática docente
(Universidade Federal de São Carlos, 2025-03-31)
Stranghetti, Natalia
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Marques, Clelia Mara de Paula
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https://lattes.cnpq.br/0451284088402660
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Venâncio, Tiago
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https://lattes.cnpq.br/4438399441102990
This study aimed to analyze the presence and development of Scientific Literacy (SC) in Basic Education, highlighting its relevance as an essential tool for understanding and applying scientific knowledge in everyday life and in the modern world. To this end, Chemistry classes were monitored in two state schools, seeking to identify the presence of SC in basic education. In addition, the teachers of these classes were interviewed, allowing a qualitative analysis based on the principles of Bardin's Content Analysis. Initially, SC indicators observed during classes were collected, while categories were created for essential aspects that did not appear, but are fundamental for the development of SC in education. In order to deepen the investigation, interviews were conducted with other teachers from the state network to understand their perceptions about SC. The research also included the analysis of legislation and documents guiding education in Brazil, such as the National Common Curricular Base (BNCC) and the Law of Guidelines and Bases of National Education, in order to verify how SC is addressed in curricula and pedagogical guidelines. The results indicated that CA is present in Basic Education, but there is a vast potential that has not yet been explored, since several essential parameters were not identified in the observed teaching practice. The study suggests that CA could be significantly more stimulated if there were greater awareness and guidance among education professionals about its importance. In addition to the lack of specific knowledge, it was found that the limited time allocated to the study of teaching tools and methods compromises the development of pedagogical practices that facilitate the learning and understanding of scientific content.
Influência da dopagem de Fe/Co sobre as propriedades dielétricas no sistema Bi3.25Nd0.75Ti3O12
(Universidade Federal de São Carlos, 2025-04-01)
Lozano, Rafael
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Zabotto, Fabio Luis
;
https://lattes.cnpq.br/8828635263888498
;
https://orcid.org/0000-0003-2868-6828
;
https://lattes.cnpq.br/5602149711574787
With the trends in environmental protection, there is a growing interest and demand in the development of lead-free ferroelectric materials to replace lead-based materials with properties suitable for various technological applications. In this context, bismuth titanate (Bi4Ti3012 - BiT) is a material with a structure of the Aurivillius family, or bismuth layers, with high potential for applications in devices and other technological apparatuses because it presents ferroic and also multiferroic properties due to its compositional manipulation and that mimic some characteristics presented by the dominant material in these applications, lead zirconate titanate (PbZr1−xTixO3 - PZT). In this case, it is possible to tune both the dielectric and ferroelectric properties and add multiferroic and/or photovoltaic properties to the BiT system through doping with chemical elements of interest. In this work, the material Bi3.25Nd0.75Ti(3−x)(Co1/2,Fe1/2)xO12 was prepared using the conventional sintering technique, which is a bismuth titanate modified with neodymium (Nd) in the Bi A site and with iron (Fe) and cobalt (Co) ions in the Ti B site. The effects of the Nd dopant confer to the BIT system the improvement of the electrical polarization, while the co-doping with Fe/Co is motivated by the search for control of the crystal structure and properties, mainly inducing multiferroic properties. Furthermore, the presence of Fe and Co in the bismuth titanate matrix can result in unexplored phenomena, such as additional phase transitions and improvement of the magnetic behavior induced by modifications. Thus, this work proposes to explore the effects of co-doping of cobalt and iron on the dielectric, pyroelectric and ferroelectric properties of the system Bi3.25Nd0.75Ti(3−x)(Co1/2,Fe1/2)xO12, with 0 ≤ x ≤ 0.4 (abbreviated as BNdTFC-x). For this purpose, impedance spectroscopy techniques and pyroelectric properties were explored in samples with different Fe/Co doping compositions, subjected to temperatures between 15 K and 980 K. The analysis allowed to identify ferroelectric-paraelectric phase transitions, as well as to investigate the influence of co-doping on the electrical and dielectric properties of the material. The results demonstrated that the introduction of Fe and Co shifts the transition temperature to higher values, but also influences the electrical conduction mechanisms, impacting the dielectric loss under certain conditions. Furthermore, the variation of critical temperatures with doping suggests relevant structural and electronic modifications, contributing to a better understanding of the ferroelectric behavior of the system. These observations make the material an interesting candidate for applications in electronic devices operating at high temperatures.
Escreventes técnico judiciários e a construção profissional de sua atuação em um foro de violência doméstica e familiar de São Paulo
(Universidade Federal de São Carlos, 2025-04-01)
Kahwage, Tharuell Lima
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Bonelli, Maria da Glória
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https://lattes.cnpq.br/1739441747281321
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https://orcid.org/0000-0003-3877-9825
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https://lattes.cnpq.br/8934697439653323
Judicial clerks are a group composed mostly of white women, who take up such positions more frequently than men, according to data from the National Council of Justice. They are responsible for practices essential to the functioning of the justice system, performing administrative and routine activities, such as filing cases, serving the public, and drafting legal documents. Despite the centrality of their role and the functions they perform, studies on this group are still incipient, especially when compared to production around the judiciary, an activity of greater preference and notoriety compared to civil servants, who tend to accumulate activities of less autonomy. Based on this scenario, the objective of this research is to understand how the position of judicial technical clerk is constructed, particularly those who work in a court of domestic and family violence against women in the state of São Paulo. I seek to analyze, through narratives produced by interactions of disputes and cooperation between themselves and other actors, what meanings they elaborate on the activities they perform, as well as how processes of gendering and racialization occur in this dynamic. This is an ethnography recorded through a field diary combined with semi-structured interviews, the data from which were subjected to content analysis. The data obtained reveal that the construction of the position is a dynamic process, shaped by social interactions of dispute and cooperation, as well as by the constant negotiation of the meanings present in their narratives.
(Des)estímulo à participação popular: inefetividade das ações populares e das ações civis públicas ajuizadas por associações na seara ambiental
(Universidade Federal de São Carlos, 2025-04-01)
Ribeiro, Elen Pessoa de Queiroz
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Oliveira, Celso Maran de
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Amarante Junior, Ozelito Possidonio de
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https://lattes.cnpq.br/1314612121213589
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https://lattes.cnpq.br/9911833172043700
As ações coletivas são importantes instrumentos que podem ser utilizados na tutela do meio ambiente. Além de conferirem segurança jurídica, estimulam a participação popular e fortalecem o exercício da democracia. Todavia, a pandemia que se iniciou no ano de 2020 acarretou uma crise humanitária que assolou o globo e marcou setores econômicos, políticos e sociais, além de afetar as atividades jurisdicionais. [...] Assim, foi possível observar que as Ações Populares são instrumentos subutilizados, bem como as Ações Civis Públicas, por parte das associações, e estão mais sujeitas a não obterem êxito na tutela do objeto pretendido.
Reciclagem de biopolimeros e a formação de substancias não intencionalmente adicionadas: uma abordagem para contato com alimento
(Universidade Federal de São Carlos, 2025-04-02)
Paiva, Robert da Silva
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Nerín de La Puerta, Maria Cristina
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https://orcid.org/0000-0003-2685-5739
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Cruz, Sandra Andrea
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https://lattes.cnpq.br/9632409046763256
The increasing demand for sustainable solutions in the packaging industry has driven the adoption of biodegradable polymers such as poly (lactic acid) (PLA). However, the efficient recycling of post-consumer PLA remains a challenge due to contamination from food residues, cleaning products, automotive substances, and improper disposal. This study addresses the optimization of the PLA recycling process, focusing on the effects of washing, the formation of recycled material for food contact applications. The influence of washing parameters on PLA degradation was evaluated using the Design of Experiments (DoE) methodology. Variables such as sodium hydroxide concentration, temperature, washing time, and surfactant concentration were analyzed. Rheological studies, based on the Cox-Merz rule, revealed that material degradation can be minimized through precise adjustment to these parameters. Specifically, surfactant concentration exhibited a less aggressive effect, even when combined with high temperatures and prolonged times. Conversely, washing time was identified as the most critical factor, particularly when paired with high temperature and sodium hydroxide concentration. The results suggest that adapting washing parameters according to the contamination level of the precursor material enables a more efficient and sustainable recycling process. In parallel, the study examined the formation of Non-Intentionally Added Substances (NIAS) and the presence of contaminants during the recycling process, a critical aspect for meeting international food standards. PLA samples were intentionally contaminated in the laboratory, washed, and mechanically recycled under simulated industrial conditions. Using Headspace Solid-Phase Microextraction with Gas-chromatography coupled Mass spectrometry (HS-SPME-GC-MS) and olfactometric analysis (HS-SPME-GC-O-MS) methods, 34 volatiles compounds were identified, including NIAS such as benzaldehyde, benzyl alcohol, and dimethyl-1,4-dioxane-1,5-dione. Additionally, 14 odor-active compounds were detected and classified into four main groups: toasted, floral, green, and chemical. The study demonstrated a correlation between the recycling stages and NIAS formation, highlighting the importance of rigorous control to ensure compliance with safety standards. The efficiency of the recycling process in contaminant removal was also evaluated following FDA guidelines. PLA samples were contaminated with a standard cocktail composed of benzophenone, tetracosane, heptane, chloroform, and toluene. After washing and mechanical recycling steps, migration tests were conducted using two food simulants under various time and temperature conditions. Analysis using SPME-GC-MS and direct injection (DI-GC-MS) showed a significant reduction in contaminants after the complete recycling cycle, with decreases ranging from 73% to 80% for substances such as tetracosane, heptane, and toluene. In comparison, washing or mechanical recycling alone showed lower removal efficiency. Factors such as the molecular volume of contaminants, type of simulant, temperature, and the interactions between PLA and contaminants directly influenced the results. Theoretical calculations of molecular interactions supported these observations, proving a detailed understanding of the underlying mechanisms. Another focus of the study was mitigating molar mass loss and oligomer formation during the recycling cycle, common challenges for materials intended for direct food contact. To address these issues, carbodiimide (CDI) was added, using co-rotating twin-screw extruders. Results showed that CDI promoted an increase in PLA molar mass and reduced oligomer formation. Moisture played a key role, as carbodiimide reacts both with water molecules, preventing hydrolytic degradation, and with PLA chains, leading to increased molar mass. Oligomer migration tests were performed using three food simulants (ethanol 10%, acetic acid 3%, and ethanol 95%) and analyzed through ultra-high performance liquid chromatography coupled with mass spectrometry (UPLC-QTOF-MSE). Sixteen types of oligomers were identified, with linear oligomers detected in all simulants and cyclic oligomers predominantly found in the ethanol 95% simulant. Theoretical calculations of electronic structure confirmed the observed interaction and migration mechanisms, offering insights into the stability and behavior of the recycled material. The addition of CDI significantly reduced the total oligomer concentration, improving the physicochemical properties of PLA and ensuring its suitability for food contact applications. In conclusion, the study demonstrated that optimizing washing parameters, controlling contaminants and NIAS, and using additives such as carbodiimide are effective strategies for improving PLA recycling. These approaches not only ensure the quality and safety of recycled material but also align with circular economy principles, contributing to the reduction of the environmental impact associated with biodegradable plastics.
Aplicação de amido termoplástico com nanopartículas de quitosana para liberação de nutrientes NPK
(Universidade Federal de São Carlos, 2025-04-02)
Franco, Rafael Augusto
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Ferreira, Marystela
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https://lattes.cnpq.br/4714185516263478
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https://orcid.org/0000-0002-9459-8167
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https://lattes.cnpq.br/7506955060907326
For this study, thermoplastic starch (TPS) films containing NPK nutrients reinforced with chitosan nanoparticles were produced and characterized, aiming at the adsorption of nutrients to them. A device for slow release of NPK nutrientes as prepared. Starch was chosen as the substrate, because it is a biodegradable polysaccharide and extremely abundant in nature. Chitosan has carrier properties on a nanometric scale, due to the increase in its contact surface and the presence of electrostatic groups in its composition. Nanochitosan was obtained through its ionic gelation, in combination with the radical polymerization of methacrylic acid. Using the dynamic light scattering (DLS) technique, an average size of 130.41 ± 1.45 nm and a zeta potential of 24.7 ± 0.7 mV were observed. Then, NPK nutrients were incorporated into the nanochitosan. The particles obtained were analyzed by transmission electron microscopy (TEM), before and after the incorporation of NPK nutrients. These were added to the preparation of thermoplastic starch (TPS) films by wet casting. The thicknesses of the films with and without nanochitosan did not show significant differences. The films with nanochitosan are more resistant to solubilization compared to films containing only NPK. The films were characterized by infrared spectroscopy (FT-IR) and contact angle analysis. The bands that appear with greater absorption intensity in the films refer to the C-O bonds (1600 cm-1) and the C-O-C bonds (between 750 cm-1 and 1000 cm-1) present in the cyclic rings of the starch structure. The contact angle was greater in the film with nanochitosan, indicating that it is capable of making the film less hydrophilic. Its release was studied in the laboratory, through the analysis of percolated samples of simulated soil in the UV-vis spectrophotometer and in situ, through application in the rooting of vegetatively propagated seedlings of the Trema Micrantha species. The percolated samples with the lowest presence of ions were those obtained from the simulated soil containing the films with nanoparticles. Better rooting was observed among the seedlings with nanoparticles. Therefore, the TPS films containing nanochitosan presented better physical properties and beneficial effect on the rooting of vegetatively propagated seedlings.
Desenvolvimento de metodologias verdes e sustentáveis para a obtenção de agentes quimioterápicos a partir de resíduos de processamento de manga (Mangifera indica L.)
(Universidade Federal de São Carlos, 2025-04-02)
Zanotti, Karine
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Forim, Moacir Rossi
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https://lattes.cnpq.br/1234565160573730
;
https://lattes.cnpq.br/7538221736303396
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https://orcid.org/0000-0003-1121-8366
Brazilian agro-industrial production generates alarming amounts of waste. In recent years, mango production has grown significantly, with the state of São Paulo among the largest producers, discarding tons of waste annually. These residues are rich in high-value bioactive compounds, and studies have investigated their antitumor potential due to the presence of secondary metabolites. Given the projected increase in cancer cases, exploring mango waste as a source of new anticancer drugs is a promising approach. Practices aligned with sustainable development should be adopted, with emphasis on using Green and Sustainable Chemistry principles, promoting the creation of products and processes that prevent the generation and use of environmentally harmful substances. Concepts such as biorefinery and circular economy are applicable in this context, utilizing biomass as a raw material to obtain new products. This study aimed to develop green and sustainable analytical methods for obtaining a chemotherapeutic agent through the extraction of secondary metabolites from mango waste. Bioassay-guided experiments on tumor cell lines, combined with spectrometric analyses using test extracts and their fractions, allowed the annotation of the target analytes: gallic acid and methyl gallate. Using chemometric techniques, two extraction methods were evaluated and optimized: homogenization-assisted extraction and microwave-assisted extraction, employing only green solvents such as water and ethanol, and considering the influence of the variables in the extraction. The extracts were analyzed by liquid chromatography coupled with mass spectrometry. The analytes were quantified based on analytical curves, demonstrating selectivity, linearity (R² > 0.999), detection and quantification limits suitable for the linear range, as well as precision (< 2%), accuracy (> 96%), and recovery (> 94%). Among the evaluated variables, ethanol composition (40% v.v⁻¹) in water and the number of extractions (1×) were the most relevant for the optimized extract obtained by homogenization. For the optimized extract obtained by microwave-assisted extraction, ethanol composition (80% v.v⁻¹) in water and temperature (70°C) were the most critical factors. The antitumor properties of test extracts, optimized extracts, and analytical standards of gallic acid and methyl gallate were evaluated in lung and ovarian cancer cell lines, as well as in non-tumor lung cells. The optimized extracts presented lower IC50 values compared to the test extracts, demonstrating greater selectivity for tumor cells. The optimized extract obtained by microwave-assisted extraction was the most promising, with IC50 values of 6.09 and 0.21 μg.mL⁻¹ for lung and ovarian tumor cells, respectively. The optimized extracts showed IC50 values comparable to the drugs cisplatin and doxorubicin, with significantly higher selectivity for tumor cells. A comparison between the extracts and analytical standards revealed a strong synergistic interaction among the matrix compounds. Morphological and clonogenic assays demonstrated that the optimized extracts exhibit cytostatic and cytotoxic profiles, indicating cell death. The results highlight the potential for reusing mango waste to obtain antitumor agents using green analytical methodologies.
Métodos de controle de qualidade aplicados a produtos cosméticos baseados em nanotecnologia
(Universidade Federal de São Carlos, 2025-04-03)
João, Luana
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Pereira Filho, Edenir Rodrigues
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https://lattes.cnpq.br/3394181280355442
Driven by consumers who are increasingly concerned with physical appearance, the cosmetics market has grown significantly in Brazil and around the world in recent years. According to data from Euromonitor International, Brazil ranks third in the global market for cosmetics and personal care products. However, alongside the growth of this sector, the public has become increasingly demanding, seeking products that not only offer traditional functions such as hydration, cleansing, and exfoliation, but also provide personalized benefits and care tailored to individual needs. This includes products that help reduce sunspots, acne, oiliness, rosacea, and more. In order to meet these consumer demands, the cosmetics industry has been investing in the development of new technologies aimed at enhancing the performance of active ingredients. Among these innovations, nanotechnology has stood out. It enables the development of cosmetic-grade materials at the nanometric scale typically between 1 to 100 nanometers which, due to their size and characteristics such as charge and surface area, exhibit unique properties that enhance their effectiveness in cosmetic formulations. Because of their reduced size, nanostructured materials used in these products present an increased surface area, which directly impacts their chemical reactivity, as well as quantum effects that significantly modify their optical and magnetic properties, for example. As a result, the application of nanotechnology in beauty products not only enhances the activity of the actives but also improves their stability, release, and skin absorption, thereby increasing the product's overall efficacy. However, before reaching consumers, cosmetic and personal care products must undergo a series of quality control tests to ensure their safety and effectiveness. These include physicochemical, organoleptic, and analytical tests. In Brazil, ANVISA is the agency responsible for the regulation of cosmetics and personal care products. Meanwhile, the FDA and the European Union provide guidance on the safety of nanomaterials used in cosmetic formulations. Therefore, this undergraduate thesis aims to present the quality control methods for cosmetic products containing active ingredients at the nanometric scale.