In-situ magnetization measurements and ex-situ morphological analysis of electrodeposited cobalt onto chemical vapor deposition graphene/SiO₂/Si

Vin?cius C. De Franco,Gustavo M. B. Castro,Jeaneth Corredor,Daniel Mendes,Jo?o E. Schmidt 한국탄소학회 2017 Carbon Letters Vol.21 No.-

Cobalt was electrodeposited onto chemical vapor deposition (CVD) graphene/Si/SiO2 substrates, during different time intervals, using an electrolyte solution containing a low concentration of cobalt sulfate. The intention was to investigate the details of the deposition process (and the dissolution process) and the resulting magnetic properties of the Co deposits on graphene. During and after electrodeposition, in-situ magnetic measurements were performed using an (AGFM). These were followed by ex situ morphological analysis of the samples with ΔtDEP 30 and 100 s by atomic force microscopy in the non-contact mode on pristine CVD graphene/SiO2/Si. We demonstrate that it is possible to electrodeposit Co onto graphene, and that in-situ magnetic measurements can also help in understanding details of the deposition process itself. The results show that the Co deposits are ferromagnetic with decreasing coercivity (HC) and demonstrate increasing magnetization on saturation (MSAT) and electric signal proportional to remanence (Mr), as a function of the amount of the electrodeposited Co. It was also found that, after the end of the dissolution process, a certain amount of cobalt remains on the graphene in oxide form (this was confirmed by X-ray photoelectron spectroscopy), as suggested by the magnetic measurements. This oxide tends to exhibit a limited asymptotic amount when cycling through the deposition/dissolution process for increasing deposition times, possibly indicating that the oxidation process is similar to the graphene surface chemistry.

Self-assembled Films of Poly(o-Ethoxyaniline) Grafted with Functionalized Multiwalled Carbon Nanotubes

Vinícius Bianchi Soares,Luis Antonio Polaci da Silva,Gabriela Martins de Araújo,Fábio Ruiz Simões 대한금속·재료학회 2020 ELECTRONIC MATERIALS LETTERS Vol.16 No.6

In this study, composites based on poly(o-ethoxyaniline), POEA, and its composites grafted with functionalized multiwalledcarbon nanotubes (MWCNT) were obtained by the oxidative in situ chemical polymerization varying the mass ratio ofo-ethoxyaniline:MWCNT of 100:1 and 100:5. POEA and its POEA-MWCNT grafted composites were used to prepare selfassembled(SA) deposited onto indium tin oxide (ITO) substrates with alternating layers of polystyrene sulfonate (PSS). Thestructure and morphology of the samples were characterized by Fourier transform infrared spectroscopy and scanning electronmicroscopy. The SA films were characterized by cyclic voltammetry, UV–Vis and electrochemical impedance spectroscopy(EIS). The EIS results showed expressive decrease of the polarization resistance (Rp), from 13,342 Ω, for POEA/PSS, to 568Ω for POEA-MWCNT(100:1)/PSS (about 23 times lower) and to 240 Ω for POEA-MWCNT(100:5)/PSS film. Consideringthat higher mass proportions of MWCNT can affect the final morphology and the oxidation ratio of POEA chains and aiming strong interactions between the POEA and MWCNT as well the significant reduction of charge transfer resistance, the SA film POEA-MWCNT(100:1)/PSS has potential for future applications as sensors and charge storage devices.

EPDM with Biochar, Carbon Black, Aramid Pulp and Ionic Liquidcompatibilized Aramid Pulp

Vinícius Demétrio da Silva,Micaela Dani Ferrari,Rosmary Nichele Brandalise,Edilson Valmir Benvenutti,Henri Stephan Schrekker,Sandro Campos Amico 한국섬유공학회 2021 Fibers and polymers Vol.22 No.4

Carbon black (CB) is a fossil fuel-derived product widely used as reinforcement in the rubber industry despite itspollution potential and its high energy-demanding production. Biochar, on the other hand, is a renewable source of carbonrecently studied for the partial substitution of CB in elastomeric materials. Aramid pulp/fibers have also been used in avariety of applications in this sector, usually after a surface treatment. In this work, the use of aramid pulp (AP) and biochar inthe preparation of ethylene propylene diene monomer (EPDM) composites and hybrid composites has been studied. The 1-nbutyl-3-methylimidazolium methanesulfonate ionic liquid (IL) was used as compatibilizer in AP, and the rubber-fillerinteraction was studied via thermal, rheometric, mechanical, and swelling analyses. The biochar-EPDM and the referenceCB-EDPM compounds showed similar hardness, modulus at 50 % strain and tear strength results. Among the tested fillers,AP was identified as the most effective to obtain EPDM composites with enhanced properties. A synergistic effect of biocharand IL-treated AP was found, resulting in higher tensile strength for the hybrid formulation (EPDM/Bio05AP05IL)compared to those with just biochar or CB, and reasonable strain at break. In all, the hybrid composites of EPDM reinforcedwith biochar and AP showed the potential to partially or fully replace CB formulations.

In-situ magnetization measurements and ex-situ morphological analysis of electrodeposited cobalt onto chemical vapor deposition graphene/SiO2/Si

Vinícius C. De Franco,Gustavo M. B. Castro,Jeaneth Corredor,Daniel Mendes,João E. Schmidt 한국탄소학회 2017 Carbon Letters Vol.21 No.-

Cobalt was electrodeposited onto chemical vapor deposition (CVD) graphene/Si/SiO2 substrates, during different time intervals, using an electrolyte solution containing a low concentration of cobalt sulfate. The intention was to investigate the details of the deposition process (and the dissolution process) and the resulting magnetic properties of the Co deposits on graphene. During and after electrodeposition, in-situ magnetic measurements were performed using an (AGFM). These were followed by ex situ morphological analysis of the samples with ΔtDEP 30 and 100 s by atomic force microscopy in the non-contact mode on pristine CVD graphene/SiO2/Si. We demonstrate that it is possible to electrodeposit Co onto graphene, and that in-situ magnetic measurements can also help in understanding details of the deposition process itself. The results show that the Co deposits are ferromagnetic with decreasing coercivity (HC) and demonstrate increasing magnetization on saturation (MSAT) and electric signal proportional to remanence (Mr), as a function of the amount of the electrodeposited Co. It was also found that, after the end of the dissolution process, a certain amount of cobalt remains on the graphene in oxide form (this was confirmed by X-ray photoelectron spectroscopy), as suggested by the magnetic measurements. This oxide tends to exhibit a limited asymptotic amount when cycling through the deposition/dissolution process for increasing deposition times, possibly indicating that the oxidation process is similar to the graphene surface chemistry.

The Promoting Effect of Carbamide Peroxide Teeth Bleaching Gel in a Preclinical Model of Head and Neck Cancer in Hamster Buccal Pouch

Vinícius Faccin Bampi,Wadson Ferreira Vilela,Reggiani Vilela Gonçalves,Maria Gabriela Tavares Rheingantz,Luiz Fernando Minello,Jefferson Luis Braga da Silva,Laura Beatriz Oliveira de Oliveira 대한이비인후과학회 2014 Clinical and Experimental Otorhinolaryngology Vol.7 No.3

Objectives. The aim of this study was to verify the promoting effect of carbamide peroxide on dimethylbenzanthracene (DMBA)-induced carcinogenesis in the hamster buccal pouch, in order to reduce the period of latency for tumor for- mation. Methods. Sixteen hamsters were randomized into two groups of eight animals each. The hamsters of the group I had their right buccal pouches treated with 0.5% DMBA and 10% carbamide peroxide teeth bleaching gel for 55 days. The an- imals of the group II had their right pouches treated only with DMBA. After, six animals of each group had their pouches prepared for light microscopy. Histomorphometry was performed to assess the presence of keratinization, nuclear polymorphism, pattern of invasion, number of blood vessels, and inflammatory infiltrate in the tumor front. Furthermore, the newly formed lesions were graded according the Bryne’s grading system. The remaining animals had the vascular system of the pouches casted by Mercox and qualitatively analyzed by scanning electron microscopy. Results. Histopathological analysis of the buccal pouches treated with DMBA and carbamide peroxide exhibited formation of squamous cell carcinoma well-differentiated with a high degree of malignancy in all pouches. The development of this neoplasm was associated with a significant increase in the number of blood vessels, presence of keratin pearls, and inflammatory infiltrate. The pouches of the group II showed inflammation, epithelial hyperplasia, dysplasia, and squamous cell carcinoma in only three right pouches. The analysis of the electron micrographs of the pouches chemi- cally inducted with DBMA and carbamide peroxide reveled formation of a new vascular network characteristic of squamous cell carcinoma. Conclusion. The protocol presented here, using DMBA associated with carbamide peroxide, shortens the period of latency to produce squamous cell carcinoma in the hamster buccal pouch, decreasing the time and costs of the experiments.

Focal Dermal Hypoplasia (Goltz Syndrome): A Case Report Showing a Wide Variety of Systemic and Oral Manifestations

Átila Vinícius Vitor Nobre,Mário Taba Júnior,Alfredo Ribeiro Silva,Sérgio Luís Scombatti de Souza,Ana Carolina Fragoso Motta 대한피부과학회 2022 Annals of Dermatology Vol.34 No.4

Focal dermal hypoplasia (FDH), also known as Goltz syndrome, consists of an unusual genodermatosis that affects tissues of ectodermal and mesodermal origin and various or- gans and systems, especially skin, bones, eyes, and oral cavity. While systemic manifesta- tions of FDH have been well documented, the oral manifestations have not been extensively discussed. We present a 22-year-old female patient with history of FDH that showed a variety of systemic and oral manifestations. FDH was diagnosed at birth based on cutane- ous alterations. Extra and intraoral examination showed facial asymmetry, lip and perioral atrophy, upper lip papilloma, malocclusion, enamel hypoplasia, and gingival hyperplasia. Mucosal lesions, periodontal diseases, and malocclusion were treated by oral surgery, peri- odontal therapy and orthodontic treatment, respectively. Although FDH is an uncommon syndrome, health professionals should be aware of its systemic and oral manifestations to establish an early diagnosis and adequate treatment.

Oxidative stress mediated cytogenotoxicological effects of phytol in wistar albino rats

Marcus Vinícius Oliveira Barros de Alencar,Muhammad Torequl Islam,Antonielly Campinho dos Reis,Santos José Victor de Oliveira,Adriana Maria Viana Nunes,Felipe Cavalcante Carneiro da Silva,Machado Keyl 경희대학교 융합한의과학연구소 2023 Oriental Pharmacy and Experimental Medicine Vol.23 No.1

Phytol (PHY), a diterpenoid, is known for its various bio-pharmacological activities. However, its toxicological profile has yet to be evaluated. The aim of this study was to evaluate the cytogenotoxicological profile of PHY in Wistar albino rats. Forty-five female non-pregnant rats were treated acutely and subchronically with PHY at doses of 300 and 2000 mg/kg and 30, 60 and 90 mg/kg for 14 and 28 days. Neuropharmacological, genotoxic, and mutagenic effects were investigated. The results suggest that PHY did not cause the death of rats at a dose of 2000 mg/kg, suggesting a higher range of the LD50 of this diterpenoid. Several toxicological alterations were observed in clinical and neuropharmacological parameters depending upon the doses. No hepatic histopathological changes were observed. PHY induced genotoxicity in peripheral blood, bone marrow, liver, and kidney. PHY did not show damage repair activity in peripheral blood lymphocytes. In the bone marrow, both acute and subchronic PHY treatments increased micronucleus frequency, indicating a mutagenic effect. PHY caused neuropharmacological alterations and genetic instability, possibly through the oxidative stress induction pathway.

Use of Bisphosphonates, Calcium and Vitamin D for Bone Demineralization in Patients with Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome: A Systematic Review and Meta-Analysis of Clinical Trials

Rocha Vinícius Magno da,Mariana Balardino Bogado Faria,Francisco de Assis dos Reis Júnior,Carla Ormundo Gonçalves Ximenes Lima,Rossano Kepler Alvim Fiorelli,Keila Mara Cassiano 대한골대사학회 2020 대한골대사학회지 Vol.27 No.3

Background: The present study performed a systematic review and meta-analysis of clinical trials using bisphosphonates for bone demineralization in human immunodeficiency virus (HIV) patients. Methods: A comprehensive literature search was performed from January 2004 to January 2020 considering the bone mineral density (BMD) of the lumbar spine (LS) as the main outcome. Out of 214 titles that met criteria, 9 studies fulfilled the selection criteria. Results: A total of 394 patients were identified, and they were allocated into 2 groups: the intervention group (200 patients), to whom a combination of alendronate or zoledronate with calcium and vitamin D was administered; and control group (194 patients), to whom only calcium and vitamin D was administered. Clinical profile and indicators of bone metabolism of the participants were evaluated regarding effect size, homogeneity, and consistency. No substantial heterogeneity between the groups was found for the baseline variables, and there was high consistency to the main outcome. The meta-analysis shows a significant difference in post-treatment BMD, favoring the intervention over the control treatment. The intervention improved LS density up to 0.227 g/cm², raising the average to the levels of general population. Adverse effects related to intervention were fever immediately after zoledronate administration and gastrointestinal complaints during alendronate usage. Other adverse effects were barely reported and poorly connected to intervention by studies’ authors, despite all of them have been successfully resolved. Conclusions: This study provides evidence that BMD post-treatment is better in HIV patients who used bisphosphonates combined with calcium and vitamin D.

Pomegranate extract on eroded dentin: antioxidant action, bond strength and morphology of the adhesive interface after aging

Cortez Thiago Vinícius,Cerqueira Nathália Mancioppi,Gallas Julia Adornes,Oliveira Wanderley Pereira,Corona Silmara Aparecida Milori,Souza-Gabriel Aline Evangelista 대한치과보존학회 2024 Restorative Dentistry & Endodontics Vol.49 No.1

Objectives This study aimed to evaluate the effect of pomegranate solution (Punica granatum) on eroded dentin through antioxidant action, shear bond strength (SBS) and interface morphology. Materials and Methods The 10% pomegranate peel extract was prepared by the lyophilization method. Punicalagin polyphenol was confirmed by high-performance liquid chromatography. Antioxidant activity was evaluated by capturing the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. For the SBS, 48 dentin fragments were divided into sound or eroded, and subdivided according to the pretreatment (n = 12): water or P. granatum. The surfaces were restored with self-etch adhesive and a bulk-fill resin (Ecosite; DMG). The SBS was done immediately (24 hours) and after thermal cycling + water storage (12 months). For scanning electron microscopy, 48 dentin fragments (24 sound and 24 eroded) received the same treatments as for SBS (n = 6), and they were analyzed after 24 hours and 12 months. Results The P. granatum had antioxidant action similar (p = 0.246) to the phenolic standard antioxidants. After 24 hours, eroded dentin had lower SBS than sound dentin (p < 0.001), regardless of the pretreatment. After 12 months, P. granatum maintained the SBS of sound dentin (13.46 ± 3.42 MPa) and eroded dentin (10.96 ± 1.90 MPa) statistically similar. The lowest values were found on eroded dentin treated with water (5.75 ± 1.65 MPa) (p < 0.001). P. granatum on eroded dentin caused peritubular demineralization and hybrid layer with resin tags. Conclusions The pomegranate extract had antioxidant action and preserved the adhesive interface of the eroded dentin. Objectives This study aimed to evaluate the effect of pomegranate solution (Punica granatum) on eroded dentin through antioxidant action, shear bond strength (SBS) and interface morphology. Materials and Methods The 10% pomegranate peel extract was prepared by the lyophilization method. Punicalagin polyphenol was confirmed by high-performance liquid chromatography. Antioxidant activity was evaluated by capturing the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. For the SBS, 48 dentin fragments were divided into sound or eroded, and subdivided according to the pretreatment (n = 12): water or P. granatum. The surfaces were restored with self-etch adhesive and a bulk-fill resin (Ecosite; DMG). The SBS was done immediately (24 hours) and after thermal cycling + water storage (12 months). For scanning electron microscopy, 48 dentin fragments (24 sound and 24 eroded) received the same treatments as for SBS (n = 6), and they were analyzed after 24 hours and 12 months. Results The P. granatum had antioxidant action similar (p = 0.246) to the phenolic standard antioxidants. After 24 hours, eroded dentin had lower SBS than sound dentin (p < 0.001), regardless of the pretreatment. After 12 months, P. granatum maintained the SBS of sound dentin (13.46 ± 3.42 MPa) and eroded dentin (10.96 ± 1.90 MPa) statistically similar. The lowest values were found on eroded dentin treated with water (5.75 ± 1.65 MPa) (p < 0.001). P. granatum on eroded dentin caused peritubular demineralization and hybrid layer with resin tags. Conclusions The pomegranate extract had antioxidant action and preserved the adhesive interface of the eroded dentin.

Optimal LQI and PID Synthesis for Speed Control of Switched Reluctance Motor Using Metaheuristic Techniques

Darielson A. Souza,Vinícius A. de Mesquita,Laurinda L. N. Reis,Wellington A. Silva,Josias G. Batista 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.1

At present, switched reluctance motors (SRM) become very interesting for many industrial applicationsin variable speed control. For such systems, the linear quadratic regulator with integral action (LQI) method iscommonly used when using plants in state spaces due to its robustness and easy adjustment. All methods from thelinear quadratic regulator (LQR) project provide a weighting of the Q and R matrices, which are manually adjustedto achieve the desired performance. The manual fine tuning of LQI controller parameters is a difficult task thatrequires a high level of domain knowledge. In this work, metaheuristic algorithms are explored to design the LQIcontroller and a comprehensive comparison is made between these algorithms and Proportional-Integral-Derivative(PID) controller as well as to select the best technique for the LQI controller design and adjustment of the Q andR parameters in SR Motor. Simulation and experimental results on a setup prototype are shown to validate theproposed control schemes. This paper has as main contributions the weighting of the parameters of the LQI in anoptimized way and adjustment of the gains of the controller more quickly and the hybrid controller (LQI + GA)becomes more powerful in the sense of a possible extension of the control of a multivariable system.