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1.
Plants (Basel) ; 12(17)2023 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-37687346

RESUMO

Nanotechnology has developed materials that can increase food production while reducing the use of conventional fertilizers. In this study, the effect of two forms of application (foliar and drench) as well as covering or non-covering of the surface of titanium dioxide nanoparticles (nTiO2) with maltodextrin (MDX) at 1500 ppm was investigated on tomato plants. The results show that treatment of tomato with nTiO2 increased yield (+21%), while covering the surface of the NPs resulted in a further yield increase (+27%). Similar trends were observed in the dry weight of vegetative plant parts. Fruit firmness (+33%) and total soluble solids (+36%) were enhanced by MDX-covered nTiO2. Application of nTiO2 resulted in enhanced SPAD index, photosynthesis rate, NO3-, K, and Ca concentration in the petiole sap, whereas in the fruits there was an increase in P and K in MDX-covered nTiO2. Considering the dilution effect due to the higher fruit yield, N, P, Mg, Cu, and B increased in plants treated with nTiO2. Covering the surface with MDX resulted in an enhanced response to nTiO2, as fruit yield and quality increased compared to plants treated with non-covered nTiO2.

2.
J Mech Behav Biomed Mater ; 147: 106108, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37713745

RESUMO

OBJECTIVES: This study aimed to develop and evaluate resin-based antibacterial materials incorporating carvone for restorative dentistry. The objectives included assessing antimicrobial activity, conversion degree, mechanical properties, hydrolytic and hygroscopic behavior, cytotoxicity, among others. METHODOLOGY: Carvone was incorporated into resin-based materials following established protocols. Antimicrobial activity was evaluated against S. Aureus. Conversion degree, polimerization kinetics, mechanical properties, hydrolytic and hygroscopic behavior, cytotoxicity, and other properties were assessed using standardized tests and methodologies. RESULTS: Carvone-incorporated materials demonstrated significant antimicrobial activity, minimal changes in conversion degree, comparable mechanical properties, improved hydrolytic and hygroscopic behavior, and lack of cytotoxicity. Antimicrobial resins were obtained due to the hydrophobic nature of carvone and its ability to diffuse through the cell walls of microorganisms, causing membrane damage. The polymerization process yielded successful conversion, ensuring adequate material performance. SIGNIFICANCE: This study showcases that incorporating carvone into methacrylate-based resins can confer antimicrobial properties while preserving key material attributes. Antimicrobial activity against S. aureus is achieved without cytotoxicity in human fibroblasts. While flexural properties are affected only at carvone concentrations exceeding 9%, conversion degree and polymerization kinetics remain stable, except for a specific experimental formulation. These findings highlight the balanced integration of carvone. However, further work, including assessing antimicrobial performance against specific strains like S. Mutans and/or C. Albicans, and evaluating long-term effectiveness, is essential to establish the potential of these materials for dental restorations.


Assuntos
Resinas Compostas , Staphylococcus aureus , Humanos , Resinas Compostas/química , Teste de Materiais , Metacrilatos/química , Antibacterianos/farmacologia , Antibacterianos/química , Polímeros , Materiais Dentários
3.
J Mech Behav Biomed Mater ; 130: 105189, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35390679

RESUMO

This work reports the synthesis of a monomer 2-((2-(3-(prop-1-en-2-yl)phenyl)propan-2-yl)carbamoyl)oxy)ethyl methacrylate (MVTPM) and the evaluation of its performance as an additive in the formulation of Bis-GMA/TEGDMA based composite resins. Experimental composite resins formulated with the MVTPM monomer were compared with a control reference. Double bond conversion, polymerization kinetics, shrinkage and associated stress, sorption, and aqueous solubility, cell viability, as well as mechanical properties were evaluated according to international measurements standards. The experimental composite resins show comparable mechanical properties with the control reference and improvements in other properties, such as better hydrolytic and hygroscopic behavior and lower shrinkage stress, are reported. This makes MVTPM monomer potentially useful in the formulation of dental composite resins.


Assuntos
Resinas Compostas , Ácidos Polimetacrílicos , Bis-Fenol A-Glicidil Metacrilato/química , Resinas Compostas/química , Teste de Materiais , Metacrilatos , Polietilenoglicóis/química , Polimerização , Ácidos Polimetacrílicos/química , Poliuretanos/química
4.
Int J Biol Macromol ; 198: 119-127, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34963627

RESUMO

Cotton gauzes were grafted with a hydrogel of maltodextrin (MD) and poly(acrylic acid) (PAAc) using N-maleyl chitosan as crosslinker to obtain materials with antimicrobial properties. Reaction parameters including monomer, crosslinker, and initiator concentrations were studied. The modification with the copolymer poly(acrylic acid)-co-maltodextrin (PAAc-co-MD) was corroborated by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The grafted gauzes (gauze-g-(PAAc-co-MD)) were able to load vancomycin and inhibit the growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. In addition, the incorporation of chitosan as crosslinker showed a synergistic effect against these bacteria. The prepared gauze-g-(PAAc-co-MD) materials could be used in the biomedical area particularly as antimicrobial wound dressings.


Assuntos
Quitosana
5.
Molecules ; 25(6)2020 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-32178255

RESUMO

Benefits of nanotechnology in agriculture include reduced fertilizer loss, improved seed germination rate and increased crops quality and yield. The objective of this research was to evaluate the effects of zinc oxide nanoparticles (ZnO-NPs), at 1500 ppm, on tomato (Solanum lycopersicum L.) growth. ZnO-NPs were synthetized to produce either spherical or hexagonal morphologies. In this research, we also studied two application methods (foliar and drench) and nanoparticles' (NPs) surface modification with maltodextrin. The results obtained indicate that ZnO-NP-treated tomato plants significantly increased plant height, stem diameter and plant organs (leaves, stem and root) dry weight compared to plants without NP treatment.


Assuntos
Biomassa , Nanopartículas Metálicas/química , Solanum lycopersicum/crescimento & desenvolvimento , Óxido de Zinco/farmacologia , Fertilizantes , Solanum lycopersicum/química , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Propriedades de Superfície/efeitos dos fármacos , Óxido de Zinco/química
6.
Carbohydr Polym ; 205: 203-210, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30446096

RESUMO

Medical cotton gauzes were modified by grafting poly(methacrylic acid) (PMAA) via free radical polymerization to obtain wound dressings with antimicrobial and drug delivery properties. The effect of several reaction parameters including monomer and initiator concentrations, reaction time, and temperature was studied. The grafting was confirmed by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), swelling studies, and scanning electron microscopy (SEM). The grafted cotton gauzes (gauze-g-PMAA) samples were loaded with ZnO nanoparticles to endow with antibacterial properties. Also, they were tested as drug eluting systems using nalidixic acid as antimicrobial agent. The antibacterial activity of the ZnO-loaded gauze-g-PMAA samples was evaluated against Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epidermidis). The PMAA-grafted gauzes showed antibacterial activity and inhibited the growth of both microorganisms. These results suggest that the PMAA-grafted cotton gauzes could be used in the biomedical area particularly as antimicrobial and drug-eluting wound dressings.


Assuntos
Antibacterianos/química , Bandagens , Celulose/química , Fibra de Algodão , Sistemas de Liberação de Medicamentos , Ácidos Polimetacrílicos/química , Celulose/síntese química , Liberação Controlada de Fármacos , Escherichia coli/efeitos dos fármacos , Ácido Nalidíxico/química , Ácido Nalidíxico/farmacologia , Nanopartículas/química , Polimerização , Ácidos Polimetacrílicos/síntese química , Staphylococcus epidermidis/efeitos dos fármacos , Óxido de Zinco/química , Óxido de Zinco/farmacologia
7.
Int J Surg Case Rep ; 29: 4-7, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27794246

RESUMO

INTRODUCTION: The thyroglossal cyst is found in 7% of the population and the incidental papillary thyroid carcinoma in thyroglossal cyst is a rare entity with an incidence 1 to 2%. The clinical presentation is indistinguishable from a benign lesion and the histopathological postoperative study defines the diagnosis. Papillary carcinomas have favorable prognosis and cervical or distant metastases are rare. There is now a consensus on the indication of total thyroidectomy, radioablation with iodine and/or suppressive therapy with levothyroxine after being removed surgically [1-3] (Patrucco et al., 2015; Gupta et al., 2014; Choi et al., 2013). CASE REPORT: 46-year-old female patient with an asymptomatic midline neck mass consistent with a thyroglossal cyst. That was excised by Sistrunk's procedure and an intraoperative biopsy that reports papillary carcinoma infiltrating the capsule. It was decide to complete the total thyroidectomy without complications, evolution is consistent and graduated euphonious and no evidence of hypoparathyroidism. DISCUSSION: Management dilemmas regarding the roles for total thyroidectomy are reviewed in the context of relevant evidence based literature. CONCLUSION: The initial evaluation of carcinoma of thyroglossal duct cyst includes careful examination, ultrasound and biopsy fine needle aspiration. Sistrunk's procedure is adequate treatment for thyroglossal cyst but find another diagnosis as papillary thyroid carcinoma makes us continue with a total thyroidectomy after discuss the case with experts [4,5] (Tharmabala and Kanthan, 2013; Miranda-Aguirre et al., 2008).

8.
J Gen Appl Microbiol ; 60(6): 262-9, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25742978

RESUMO

The production of glucose oxidase (GOX) and catalase (CAT) by submerged fermentation of the free and immobilized xerophytic fungus Aspergillus niger under equal conditions was compared. To immobilize fungal spores, entrapment in PVA/alginate beads treated with NaNO3/CaCl2 was performed. The yield of immobilization in the beads with a diameter less than 1mm was equal to 100%. Fungus growth and substrate consumption were evaluated in both fermentation systems, demonstrating the lag-period presence in the case of the first cycle of immobilized fungus use. The enzyme production by immobilized fungus reuse was carried out. In these cases, greater enzymatic GOX activity was detected, while CAT activity decreased. SEM micrographs for the beads with immobilized fungus applied in the first and second fermentation cycles were obtained, presenting fungus spreading inside the sphere, spore presence and branching hyphae. Immobilization of A. niger on PVA/alginate beads is effective for GOX and CAT production at least on 2-3 repeated fermentative cycles. Thus, immobilization enables repeated use of microbial cells.


Assuntos
Aspergillus niger/enzimologia , Aspergillus niger/metabolismo , Catalase/metabolismo , Glucose Oxidase/metabolismo , Alginatos , Células Imobilizadas/metabolismo , Fermentação , Ácido Glucurônico , Ácidos Hexurônicos , Microscopia Eletrônica de Varredura , Microesferas , Álcool de Polivinil
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