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1.
J Toxicol Environ Health A ; 87(2): 47-56, 2024 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-37882219

RESUMO

Among biotic and abiotic stresses, the most restrictive for plant distribution is salt stress, where different concentrations might exert harmful effects on seed germination. Recently, nanomaterials were used successfully to mitigate these stresses, indicating that plants may be able to develop normally in adverse conditions. The aim of this study was to examine the effects of graphene oxide (GO) on the germination of Persian clover seedlings under salt stress conditions. Following sown on substrate paper, seeds were tested after exposure to different concentrations of graphene oxide (0, 125, 250, or 500 mg L-1 GO), sodium chloride (0; -0.1; -0.2; -0.3, or -0.4 MPa NaCl) and/or GO + salt concomitantly, and then stored for 7 days in a germination chamber at 20°C in the presence of light. Seed germination and growth parameters of seedlings were determined. Graphene oxide demonstrated protective effect against salt stress as evident by no marked adverse effects on seed germination where GO blocked the salt-induced reduction in germination. The results obtained provide references for the safe application of nanomaterials and emphasize the significance of GO as a promising material for reducing the toxicity of salts in agriculture.


Assuntos
Germinação , Sementes , Estresse Salino , Plântula
2.
J Toxicol Environ Health A ; 87(5): 199-214, 2024 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-38073506

RESUMO

Several medicinal plants have been administered to cancer patients attributed to their anticarcinogenic and chemoprotective properties, in addition to lower toxicity compared to traditional therapies. The aim was to investigate the antioxidant properties and carotenoid composition of aqueous extracts of Mentha piperita or Artemisia vulgaris which were previously found to exert beneficial effects on human health through diet. aqueous extracts exhibited potent antioxidant activity. A diversity of carotenoids was identified in these extracts using HPLC-PDA-MS/MS. Both extracts contained predominantly all-trans-lutein as the main component within this class. In order to investigate antioxidant properties, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) techniques were used. The (3-4,5 dimethylthiazol-2, 5 diphenyl tetrazolium bromide) (MTT) and Crystal Violet assays assessed cellular cytotoxicity. Assessments of presence of reactive species were carried out following exposure of oral squamous cell carcinoma cell line (SCC-4) to various aqueous extracts of M piperita or A vulgaris utilizing dichlorofluorescein diacetate (DCFH-DA) and nitric oxide (NO) assays. Exposure to these extracts induced severe cytotoxic effects, which led to investigation of the biochemical and molecular mechanisms underlying this observed effect. Data demonstrated that both solutions induced oxidative stress and DNA damage, especially at higher concentrations using agarose gel subjected to electrophoresis. It is known that exposure to excess amounts of antioxidants results in a prooxidant effect which is beneficial in cancer therapy. Further, the extracts were found to reduce viability of SCC-4 in culture, indicating that this antitumoral activity may be of therapeutic importance and requires further study.


Assuntos
Artemisia , Carcinoma de Células Escamosas , Neoplasias Bucais , Humanos , Antioxidantes/farmacologia , Antioxidantes/química , Mentha piperita/química , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Espectrometria de Massas em Tandem , Clivagem do DNA , Compostos Fitoquímicos , Carotenoides/farmacologia
3.
J Toxicol Environ Health A ; 86(2-3): 51-68, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36543759

RESUMO

Vassobia breviflora (Sendtn.) Hunz is a plant of the Solanaceae family from South America and there are no apparent studies reported on the biological activity of the hexane extract. The aim of this investigation was to conduct phytochemical analyses using ESI-TOF-MS, while antioxidant activities were evaluated by the following methods 1,1-diphenyl-2-picrylhydrazyl (DPPH) 2,2"-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical capture (ABTS), ferric reducing antioxidant power (FRAP), total antioxidant capacity (TAC), and total oxidant status (TOS). Antimicrobial activities were performed by determining the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and antibiofilm formed. Cytotoxicity was measured by MTT and dsDNA PicoGreen tests, beyond the production of reactive oxygen species (ROS) determined by Dichlorodihydrofluorescein diacetate (DCFH-DA). The hexane extract showed the presence of 5 (choline, pantothenic acid, calystegine B, lanciphodylactone I, and 15"-cis-zeaxanthin) compounds detected. V. breviflora extract demonstrated reliable results utilizing different antioxidant methods. In antibacterial activity, V. breviflora extract exhibited inhibitory, bactericidal, and antibiofilm action in biofilm-forming bacteria. The hexane extract exhibited cytotoxicity against melanoma, lung cancer, glioblastoma, leukemia, uterine colon, and hepatocarcinoma tumor cells. In addition, all tested strains resulted in increased production of ROS. This plant extract may be considered in future as an alternative for development of new therapeutic options aimed at the treatment of diverse pathologies.


Assuntos
Antioxidantes , Solanaceae , Antioxidantes/farmacologia , Antioxidantes/química , Espécies Reativas de Oxigênio , Hexanos , Antibacterianos/farmacologia , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Compostos Fitoquímicos/farmacologia
4.
J Toxicol Environ Health A ; 86(21): 816-832, 2023 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-37667472

RESUMO

The particular plant species found in southern Brazil, Vassobia breviflora (Solanaceae) has only a few apparent studies examining its biological effect. Thus, the aim of the present study was to determine the activity of the acetone extract fraction derived from V. breviflora. Four compounds were identified by ESI-qTOF-MS: eucalrobusone R, aplanoic acid B, pheophorbide A, and pheophytin A. In addition, 5 compounds were identified by HPLC-PDA-MS/MS: all-trans-lutein, 15-cis-lutein, all-trans-ß-carotene, 5,8-epoxy-ß-carotene, and cis-ß-carotene. Cell lines A549 (lung cancer), A375 (melanoma cancer) and HeLa (cervical cancer) were incubated with different concentrations of each studied extract using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH), and 2'-7'dichlorofluorescin diacetate (DCFH-DA) assays. The acetonic extract exhibited cytotoxic activity at a concentration of 0.03 mg/ml in the HeLa strain and 0.1 mg/ml in the others. In addition to increased production of reactive oxygen species (ROS). Antibacterial activity was assessed utilizing minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in 9 ATCCs strains and 7 clinical isolates, as well as determination of biofilm production. Data demonstrated that MIC and MBC were approximately 256 mg/ml in most of the strains tested and antibiofilm effect at S. aureus, S. epidermidis, A. baumannii, and E. faecalis, concentrations below the MIC. Genotoxic activity on plasmid DNA did not produce significant elevated levels in breaks in the isolated genetic material.


Assuntos
Acetona , Luteína , Staphylococcus aureus , Espectrometria de Massas em Tandem , beta Caroteno , Brasil
5.
Chemistry ; 24(9): 2214-2223, 2018 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-29220553

RESUMO

Dibenzo[a,j]coronene-tetracarboxylic alkyl esters and imides with either a centrosymmetric bis-peri substitution pattern or a polar bis-ortho substitution pattern form hexagonal columnar mesophases, which in the case of the imides persist at room temperature. The bis-peri isomers are obtained via a two-fold oxidative photocyclization; the bis-ortho isomers are accessed via a glyoxylic Perkin reaction of triphenylene and naphthalene building blocks. Steric congestion between the substituents and the adjacent benzo protrusion in the bis-ortho esters and imides leads to bending of the aromatic plane, which thus avoids twisting. These isomers surprisingly show a more pronounced liquid crystalline behaviour than their non-bent bis-peri homologs, accommodating non-planarity with columnar order by slipped stacking. Whereas both types of ester and the bis-peri imide show an optical behaviour typical for perylene chromophores, the strongly bent bis-ortho imide distinguishes itself notably from them by its absorption spectrum. The electron acceptor strength of the isomeric diimides is found to differ, the hexagonal (peri) diimide having a 0.20 eV lower LUMO energy than the pentagonal (ortho) isomer.

6.
Chemistry ; 22(24): 8043-7, 2016 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-27141916

RESUMO

The twofold glyoxylic Perkin reaction of perylene-3,9-diglyoxylic acid with thiophene-diacetic acid followed by oxidative photocylization and reaction with α-branched primary alkylamines yields columnar liquid-crystalline diimides with two sulfur atoms in the condensed arene system. A broad temperature range of the hexagonal columnar mesophase is induced by racemic doubly branched alkyl chains. The HOMO and LUMO energy levels of these thiophene-derived diimides qualify them as electron donors with respect to perylene diimides.

7.
Chemistry ; 22(22): 7389-93, 2016 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-27145525

RESUMO

Whereas perylene tetracarboxdiimides derived from amino-n-alkanes if at all only show monotropic (thermodynamically unstable) mesogenic self-assembly, the hexagonal columnar liquid crystalline state can be stabilized over a broad temperature range with doubly branched, doubly racemic alkyl residues. An improved tendency to homeotropic surface orientation is observed, and the orientation of the liquid crystalline domains is maintained upon cycling through the crystalline state at room temperature.

8.
Phys Chem Chem Phys ; 16(7): 2892-6, 2014 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-24424377

RESUMO

The incorporation of dyes in liquid crystal matrices has been exploited to produce enhanced displays, but it can also be used to probe ordering in liquid crystals and to assess intermolecular interactions and dye aggregation. In this study, we investigated polarized absorption and emission of the luminescent dyes 4,7-bis(2-(4-(decyloxy)phenyl)ethynyl)-[2,1,3]-benzothiadiazole (1A) and 4,7-bis{2-[4-(4-decylpiperazin-1-yl)phenyl]ethynyl}-[2,1,3]-benzothiadiazole (5A) in the E7® liquid crystal. The electronic structures of both 1A and 5A dyes were affected by the matrix and by the analysis of the line shape of emission we could determine that the dyes form J aggregates. This achievement is significant because obtaining this type of information for small molecules requires ordered matrices, which is difficult to obtain for these dyes. Using emission ellipsometry we were able to determine the ordering of the E7 molecules, but this was possible only with the larger 5A dye. The smaller 1A was not entirely ordered in the E7 matrix and this calls for caution in other types of work where dopants are used as probes to infer the properties of the matrix. The emission ellipsometry data for the dyes allowed us to detect the enhanced birefringence in the matrix, thus confirming the theoretical prediction.

9.
Acta Crystallogr Sect E Struct Rep Online ; 70(Pt 5): o559, 2014 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-24860366

RESUMO

In the title compound, C11H10N2O3, which is a potential bioactive compound, the benzene and oxa-diazole rings are approximately coplanar, with an inter-ring dihedral angle of 4.14 (2)°, while the ester plane is rotated out of the benzene plane [dihedral angle = 82.69 (9)°]. In the crystal, the mol-ecules form layers down the a axis with weak π-π inter-actions between the oxa-diazole and benzene rings [minimum ring centroid separation = 3.7706 (14) Å].

10.
Environ Sci Pollut Res Int ; 31(17): 25437-25453, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38472573

RESUMO

2,4-Dichlorophenoxyacetic acid (2,4-D) is an herbicide and is among the most widely distributed pollutant in the environment and wastewater. Herein is presented a complete comparison of adsorption performance between two different magnetic carbon nanomaterials: graphene oxide (GO) and its reduced form (rGO). Magnetic functionalization was performed employing a coprecipitation method, using only one source of Fe2+, requiring low energy, and potentially allowing the control of the amount of incorporated magnetite. For the first time in literature, a green reduction approach for GO with and without Fe3O4, maintaining the magnetic behavior after the reaction, and an adsorption performance comparison between both carbon nanomaterials are demonstrated. The nanoadsorbents were characterized by FTIR, XRD, Raman, VSM, XPS, and SEM analyses, which demonstrates the successful synthesis of graphene derivate, with different amounts of incorporate magnetite, resulting in distinct magnetization values. The reduction was confirmed by XPS and FTIR techniques. The type of adsorbent reveals that the amount of magnetite on nanomaterial surfaces has significant influence on adsorption capacity and removal efficiency. The procedure demonstrated that the best performance, for magnetic nanocomposites, was obtained by GO∙Fe3O4 1:1 and rGO∙Fe3O4 1:1, presenting values of removal percentage of 70.49 and 91.19%, respectively. The highest adsorption capacity was reached at pH 2.0 for GO∙Fe3O4 1:1 (69.98 mg g-1) and rGO∙Fe3O4 1:1 (89.27 mg g-1), through different interactions: π-π, cation-π, and hydrogen bonds. The adsorption phenomenon exhibited a high dependence on pH, initial concentration of adsorbate, and coexisting ions. Sips and PSO models demonstrate the best adjustment for experimental data, suggesting a heterogeneous surface and different energy sites, respectively. The thermodynamic parameters showed that the process was spontaneous and exothermic. Finally, the nanoadsorbents demonstrated a high efficiency in 2,4-D adsorption even after five adsorption/desorption cycles.


Assuntos
Grafite , Herbicidas , Nanocompostos , Poluentes Químicos da Água , Adsorção , Herbicidas/análise , Grafite/química , Óxido Ferroso-Férrico , Água/química , Nanocompostos/química , Fenômenos Magnéticos , Ácido 2,4-Diclorofenoxiacético , Cinética , Poluentes Químicos da Água/análise , Concentração de Íons de Hidrogênio
11.
Front Med (Lausanne) ; 11: 1347517, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38903812

RESUMO

Introduction: Currently, Chronic Obstructive Pulmonary Disease (COPD) has a high impact on morbidity and mortality worldwide. The increase of CD4+, CD8+ cells expressing NF-κB, STAT4, IFN-γ and perforin are related to smoking habit, smoking history, airflow rate, obstruction and pulmonary emphysema. Furthermore, a deficiency in CD4+CD25+Foxp3+ regulatory T cells (Tregs) may impair the normal function of the immune system and lead to respiratory immune disease. On the other hand, the anti-inflammatory cytokine IL-10, produced by Treg cells and macrophages, inhibits the synthesis of several pro-inflammatory cytokines that are expressed in COPD. Therefore, immunotherapeutic strategies, such as Photobiomodulation (PBM), aim to regulate the levels of cytokines, chemokines and transcription factors in COPD. Consequently, the objective of this study was to evaluate CD4+STAT4 and CD4+CD25+Foxp3+ cells as well as the production of CD4+IFN- γ and CD4+CD25+IL-10 in the lung after PBM therapy in a COPD mice model. Methods: We induced COPD in C57BL/6 mice through an orotracheal application of cigarette smoke extract. PMB treatment was applied for the entire 7 weeks and Bronchoalveolar lavage (BAL) and lungs were collected to study production of IFN- γ and IL-10 in the lung. After the last administration with cigarette smoke extract (end of 7 weeks), 24 h later, the animals were euthanized. One-way ANOVA followed by NewmanKeuls test were used for statistical analysis with significance levels adjusted to 5% (p < 0.05). Results: This result showed that PBM improves COPD symptomatology, reducing the number of inflammatory cells (macrophages, neutrophils and lymphocytes), the levels of IFN-γ among others, and increased IL-10. We also observed a decrease of collagen, mucus, bronchoconstriction index, alveolar enlargement, CD4+, CD8+, CD4+STAT4+, and CD4+IFN-γ+ cells. In addition, in the treated group, we found an increase in CD4+CD25+Foxp3+ and CD4+IL-10+ T cells. Conclusion: This study suggests that PBM treatment could be applied as an immunotherapeutic strategy for COPD.

12.
Environ Sci Pollut Res Int ; 30(5): 12658-12671, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36114403

RESUMO

Due to its wide use in anticonvulsant pharmacotherapy, phenobarbital (PHEN) is an aquatic contaminant with a high prevalence in the environment. In this adsorption study, chitosan and chitosan-based magnetic adsorbents containing different amounts of incorporated magnetite (CS, CS·Fe3O4 1:1, CS·Fe3O4 1:5, and CS·Fe3O4 1:10) were used for phenobarbital removal. The magnetic adsorbents were synthesized by co-precipitation method and characterized through FTIR, XRD, MEV, and VSM analysis. In PHEN adsorption, the equilibrium and adsorption kinetic were better adjusted by the Sips and pseudo-second-order model, respectively. Among the four nanoadsorbents used, the maximum phenobarbital adsorption capacity was 94.60 mg g-1 using 25 mg of CS·Fe3O4 1:5, with a concentration of PHEN (50 mg L-1), pH 7.0 at room temperature. The parameters of pH, adsorbent dosage, ionic strength, and thermodynamic study were tested for the adsorbent with the highest performance (CS·Fe3O4 1:5). The nanoadsorbent demonstrates efficiency in the removal of the contaminant for diverse adsorption cycles. Finally, the protocol employing magnetic adsorbents dispenses the subsequent steps of filtration and centrifugation.


Assuntos
Quitosana , Poluentes Químicos da Água , Purificação da Água , Quitosana/química , Óxido Ferroso-Férrico/química , Concentração de Íons de Hidrogênio , Termodinâmica , Adsorção , Água/química , Cinética , Poluentes Químicos da Água/química , Purificação da Água/métodos , Fenobarbital
13.
Cancer Diagn Progn ; 3(6): 616-634, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37927802

RESUMO

Renal neoplasms are highlighted as one of the 10 most common types of cancer. Renal cell carcinoma (RCC) is the most common type of renal cancer, considered the seventh most common type of cancer in the Western world. The most frequently altered genes described as altered are VHL, PBRM1, SETD2, KDM5C, PTEN, BAP1, mTOR, TP53, TCEB1 (ELOC), SMARCA4, ARID1A, and PIK3CA. RCC therapies can be classified in three groups: monoclonal antibodies, tyrosine kinase inhibitors, and mTOR inhibitors. Besides, there are targeted agents to treat RCC. However, frequently patients present side effects and resistance. Even though many multidrug resistance mechanisms already have been reported to RCC, studies focused on revealing new biomarkers as well as more effective antitumor therapies with no or low side effects are very important. Some studies reported that natural products, such as honey, epigallocatechin-3-gallate (EGCG), curcumin, resveratrol, and englerin A showed antitumor activity against RCC. Moreover, nanoscience is another strategy to improve RCC treatment and reduce the side effects due to the improvement in pharmacokinetics and reduction of toxicities of chemotherapies. Taking this into account, we conducted a systemic review of recent research findings on RCC hallmarks, drug resistance, and adjuvant therapies. In conclusion, a range of studies reported that RCC is characterized by high incidence and increased mortality rates because of the development of resistance to standard therapies. Given the importance of improving RCC treatment and reducing adverse effects, nanoscience and natural products can be included in therapeutic strategies.

14.
Langmuir ; 28(31): 11590-8, 2012 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-22747343

RESUMO

Five discotic molecules comprising a tris[1,2,4]triazolo[1,3,5] triazine core were designed and synthesized to obtain luminescent and charge-transporting columnar liquid crystalline materials. With the exception of one compound containing terminal hydroxyl groups all compounds presented a wide thermal range and stable columnar liquid crystalline phase, characterized by differential scanning calorimetry, polarized optical microscopy, and X-ray diffraction (XRD) techniques. The phase formation appeared to be associated to some extent with interdigitation of the alkoxy and benzylalkoxy portion, as suggested by the XRD results. All compounds have a strong blue luminescence in solution and solid phase. At the temperature at which the compounds enter in the mesophase the luminescence decreases significantly. This result suggests that entrance into the Col(h) phase is accompanied by a better π-stacking of the peripheral phenyl rings compared to the solid phase, consistent with the intramolecular distances (3.5 Å) observed in the XRD analysis. These compounds based on tristriazolotriazine are quite robust with good optical and thermal properties for application as solid state emitters, and we anticipate that they may provide an interesting alternative to other discotic molecules based on N-heterocycles, which generally present a high-temperature Col(h) phase.

15.
ACS Appl Electron Mater ; 4(7): 3486-3494, 2022 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-35910938

RESUMO

Delayed fluorescence (DF) by triplet-triplet annihilation (TTA) is observed in solutions of a benzoperylene-imidoester mesogen that shows a hexagonal columnar mesophase at room temperature in the neat state. A similar benzoperylene-imide with a slightly smaller HOMO-LUMO gap, that also is hexagonal columnar liquid crystalline at room temperature, does not show DF in solution, and mixtures of the two mesogens show no DF in solution either, because of collisional quenching of the excited triplet states on the imidoester by the imide. In contrast, DF by TTA from the imide but not from the imidoester is observed in condensed films of such mixtures, even though neat films of either single material are not displaying DF. In contrast to the DF from the monomeric imidoester in solution, DF of the imide occurs from dimeric aggregates in the blend films, assisted by the imidoester. Thus, the close contact of intimately stacked molecules of the two different species in the columnar mesophase leads to a unique mesophase-assisted aggregate DF. This constitutes the first observation of DF by TTA from the columnar liquid crystalline state. If the imide is dispersed in films of polybromostyrene, which provides an external heavy-atom effect facilitating triplet formation, DF is also observed. Organic light-emitting diodes (OLEDs) devices incorporating these liquid crystal molecules demonstrated high external quantum efficiency (EQE). On the basis of the literature and to the best of our knowledge, the EQE reported is the highest among nondoped solution-processed OLED devices using a columnar liquid crystal molecule as the emitting layer.

16.
Environ Sci Pollut Res Int ; 29(3): 3794-3807, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34396477

RESUMO

The pollution of wastewater with dyes has become a serious environmental problem around the world. In this context, the work aims to synthesize and characterize a supported nanocatalyst (NZ-180) from rice husk (RH) and alum sludge (AS) incorporating silver (AgNPs@NZ-180) and titanium nanoparticles (TiNPs@NZ-180) for Rhodamine B (RhB) dye degradation, under UV and visible irradiation. Central rotatable composite design (CRCD) was used to determine ideal conditions, using nanocatalyst and dye concentration such as input variables and degradation percentage like response variable. Samples were characterized by XRD, SEM-EDS, N2 porosimetry, DLS, and zeta potential analyses. TiNPs@NZ-180 showed the best photocatalytic activity (62.62 and 50.82% under UV and visible irradiation, respectively). Specific surface area has increased from 35.90 to 418.90 m2 g-1 for NZ-180 and TiNPs@NZ-180, respectively. Photocatalytic performance of TiNPs@NZ-180 has reduced to 8 and 10% after 5 cycles under UV and visible light irradiation. Ideal conditions found by CRCD were 2.75 g L-1 and 20 mg L-1 for nanocatalyst and RhB concentrations, respectively. Therefore, (agro)industrial waste present such an alternative material for application in the removal of wastewater with dyes, which helps in the reduction of the impact of chemicals/pollutants on human and animal health.


Assuntos
Resíduos Industriais , Prata , Animais , Catálise , Corantes , Humanos , Luz , Titânio , Águas Residuárias
17.
Polymers (Basel) ; 14(22)2022 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-36432981

RESUMO

Herein, tetracycline adsorption employing magnetic chitosan (CS·Fe3O4) as the adsorbent is reported. The magnetic adsorbent was synthesized by the co-precipitation method and characterized through FTIR, XRD, SEM, and VSM analyses. The experimental data showed that the highest maximum adsorption capacity was reached at pH 7.0 (211.21 mg g-1). The efficiency of the magnetic adsorbent in tetracycline removal was dependent on the pH, initial concentration of adsorbate, and the adsorbent dosage. Additionally, the ionic strength showed a significant effect on the process. The equilibrium and kinetics studies demonstrate that Sips and Elovich models showed the best adjustment for experimental data, suggesting that the adsorption occurs in a heterogeneous surface and predominantly by chemical mechanisms. The experimental results suggest that tetracycline adsorption is mainly governed by the hydrogen bonds and cation-π interactions due to its pH dependence as well as the enhancement in the removal efficiency with the magnetite incorporation on the chitosan surface, respectively. Thermodynamic parameters indicate a spontaneous and exothermic process. Finally, magnetic chitosan proves to be efficient in TC removal even after several adsorption/desorption cycles.

18.
Environ Sci Pollut Res Int ; 29(46): 70413-70434, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35585459

RESUMO

Emerging pollutants are a group of substances involved in environmental contamination resulting mostly from incomplete drug metabolism, associated with inadequate disposal and ineffective effluent treatment techniques. Methotrexate (MTX), for instance, is excreted at high concentrations in unchanged form through the urine. Although the MTX is still effective in cancer and autoimmune disease treatment, this drug shows the ability of bioaccumulation and toxicity to the organism. Thus, the present work aimed to evaluate the adsorption of the MTX drug onto magnetic nanocomposites containing different amounts of incorporated magnetite (1:1, 1:5, and 1:10 wt%), combining the theoretical-experimental study as well as the in vitro cytotoxicity. Moreover, equilibrium studies (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Hill, Redlich-Peterson, and Sips), kinetic (PFO, PSO, and IPD), and thermodynamic (ΔG°, ΔH°, and ΔS°) were used to describe the experimental data, and ab initio simulations were employed in the theoretical study. Magnetic nanocomposites were synthesized by the co-precipitation method using only FeCl2 as the iron precursor. Adsorbents were characterized by FTIR, XRD, Raman, SEM-EDS, BET, and VSM analysis. Meanwhile, cytotoxic effects on L929 and A375 cell lines were evaluated through MTT, NR, and LDH assays. The adsorption of the MTX was carried out in a typical batch system, exploring the different experimental conditions. The theoretical study suggests the occurrence of chemisorption between CS·Fe3O4-MTX. The maximum adsorption capacity of MTX was 285.92 mg g-1, using 0.125 g L-1 of CS·Fe3O4 1:1, with an initial concentration of the MTX (50 mg L-1), pH 4.0 at 293 ± 1.00 K. The best adjustment of equilibrium and kinetic data were the Sips (low values for statistical errors) and PSO (qe = 96.73 mg g-1) models, respectively. Thermodynamic study shows that the adsorption occurred spontaneously (ΔG° < 0), with exothermic (ΔH° = - 4698.89 kJ mol-1) and random at the solid-solution interface (ΔS° = 1,476,022.00 kJ mol-1 k-1) behavior. Finally, the in vitro study shows that magnetic nanomaterials exhibit higher cytotoxicity in melanoma cells. Therefore, the magnetic nanocomposite reveals to be not only an excellent tool for water remediation studies but also a promising platform for drug delivery.


Assuntos
Quitosana , Poluentes Químicos da Água , Adsorção , Óxido Ferroso-Férrico , Concentração de Íons de Hidrogênio , Ferro/análise , Cinética , Metotrexato/análise , Temperatura , Termodinâmica , Água , Poluentes Químicos da Água/análise
19.
Chem Soc Rev ; 39(5): 1435-47, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20419199

RESUMO

The simple structures of neutral triatomic molecules mask the complexity of their many reactions. Several of them are involved with our life cycle, and an example of their importance is witnessed by the now recognized effect of CO(2) on our climate. In this tutorial review, we provide a basis for understanding why these triatomics react with other species, and show examples of how their chemistry has been exploited to synthesize complex molecules and aggregates, to change drastically the properties of materials, and to devise new processes.

20.
Front Immunol ; 12: 789426, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35185864

RESUMO

It is largely known that photobiomodulation (PBM) has beneficial effects on allergic pulmonary inflammation. Our previous study showed an anti-inflammatory effect of the PBM in an acute experimental model of asthma, and we see that this mechanism is partly dependent on IL-10. However, it remains unclear whether the activation of regulatory T cells is mediated by PBM in a chronic experimental model of asthma. In this sense, the objective of this study was to verify the anti-inflammatory role of the PBM in the pulmonary inflammatory response in a chronic experimental asthma model. The protocol used for asthma induction was the administration of OVA subcutaneously (days 0 and 14) and intranasally (3 times/week, for 5 weeks). On day 50, the animals were sacrificed for the evaluation of the different parameters. The PBM used was the diode, with a wavelength of 660 nm, a power of 100 mW, and 5 J for 50 s/point, in three different application points. Our results showed that PBM decreases macrophages, neutrophils, and lymphocytes in the bronchoalveolar lavage fluid (BALF). Moreover, PBM decreased the release of cytokines by the lung, mucus, and collagen in the airways and pulmonary mechanics. When we analyzed the percentage of Treg cells in the group irradiated with laser, we verified an increase in these cells, as well as the release of IL-10 in the BALF. Therefore, we conclude that the use of PBM therapy in chronic airway inflammation attenuated the inflammatory process, as well as the pulmonary functional and structural parameters, probably due to an increase in Treg cells.


Assuntos
Asma , Interleucina-10 , Terapia com Luz de Baixa Intensidade , Animais , Anti-Inflamatórios/farmacologia , Asma/tratamento farmacológico , Asma/radioterapia , Linfócitos T CD4-Positivos , Modelos Animais de Doenças , Fatores de Transcrição Forkhead , Inflamação , Interleucina-10/metabolismo , Pulmão , Camundongos , Camundongos Endogâmicos BALB C , Ovalbumina
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