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1.
Int J Nanomedicine ; 16: 1725-1741, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33688188

RESUMO

Purpose: This study systematically investigated the potential of four model drugs (verapamil HCl, flurbiprofen, atenolol, and furosemide), each belonging to a different class of Biopharmaceutics Classification Systems (BCS) to be developed into oral modified release dosage forms after loading with halloysite nanotubes (HNTs). Methods: The drugs were studied for their loading (mass gain %) by varying solvent system, method, pH, and ratios of loading into the nanotubes using D-optimal split-plot design with the help of Design Expert software. Drug-loaded halloysites were characterized by XRD, DTA, FTIR, SEM, and HPLC-UV-based assay procedures. Dissolution studies were also performed in dissolution media with pH 1.2, 4.5, and 6.8. Moreover, the optimized samples were evaluated under stress stability conditions for determining prospects for the development of oral dosage forms. Results: As confirmed with the results of XRD and DTA, the drugs were found to be converted into amorphous form after loading with halloysite (HNTs). The drugs were loaded in the range of ~7-9% for the four drugs, with agitation providing satisfactory and equivalent loading as compared to vacuum plus agitation based reported methods. FTIR results revealed either only weak electrostatic (verapamil HCl and flurbiprofen) or no interaction with the surface structure of the HNTs. The dissolution profiling depicted significantly retarded release of drugs with Fickian diffusion from a polydisperse system as a model that suits well for the development of oral dosage forms. HPLC-UV-based assay indicated that except furosemide (BCS class IV), the other three drugs are quite suitable for development for oral dosage forms. Conclusion: The four drugs investigated undergo phase transformation with HNTs. While agitation is an optimum method for loading drugs with various physicochemical attributes into HNTs; solvent system, loading ratios and pH play an important role in the loading efficiency respective to the drug properties. The study supports the capability of developing HNT-based modified release oral dosage forms for drugs with high solubility.


Assuntos
Biofarmácia/classificação , Argila/química , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Nanotubos/química , Preparações Farmacêuticas/administração & dosagem , Administração Oral , Silicatos de Alumínio/química , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
2.
Molecules ; 26(3)2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33525610

RESUMO

Precious metals, in particular Pd, have a wide range of applications in industry. Due to their scarcity, precious metals have to be recycled, preferably with green and energy-saving recycling processes. In this article, palladium extraction from an aluminosilicate-supported catalyst, containing about 2 wt% (weight%) of Pd (100% PdO), with supercritical CO2 (scCO2) assisted by complexing polymers is described. Two polymers, p(FDA)SH homopolymer and p(FDA-co-DPPS) copolymer (FDA: 1,1,2,2-tetrahydroperfluorodecyl acrylate; DPPS: 4-(diphenylphosphino)styrene), were tested with regards to their ability to extract palladium. Both polymers showed relatively low extraction conversions of approximately 18% and 30%, respectively. However, the addition of piperidine as activator for p(FDA-co-DPPS) allowed for an increase in the extraction conversion of up to 60%.


Assuntos
Silicatos de Alumínio/química , Dióxido de Carbono/química , Paládio/química , Piperidinas/química , Polímeros/química , Acrilatos/química , Catálise , Reciclagem/métodos , Estireno/química
3.
Nat Commun ; 12(1): 1124, 2021 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-33602928

RESUMO

Clay-based nanomaterials, especially 2:1 aluminosilicates such as vermiculite, biotite, and illite, have demonstrated great potential in various fields. However, their characteristic sandwiched structures and the lack of effective methods to exfoliate two-dimensional (2D) functional core layers (FCLs) greatly limit their future applications. Herein, we present a universal wet-chemical exfoliation method based on alkali etching that can intelligently "capture" the ultrathin and biocompatible FCLs (MgO and Fe2O3) sandwiched between two identical tetrahedral layers (SiO2 and Al2O3) from vermiculite. Without the sandwich structures that shielded their active sites, the obtained FCL nanosheets (NSs) exhibit a tunable and appropriate electron band structure (with the bandgap decreased from 2.0 eV to 1.4 eV), a conductive band that increased from -0.4 eV to -0.6 eV, and excellent light response characteristics. The great properties of 2D FCL NSs endow them with exciting potential in diverse applications including energy, photocatalysis, and biomedical engineering. This study specifically highlights their application in cancer theranostics as an example, potentially serving as a prelude to future extensive studies of 2D FCL NSs.


Assuntos
Silicatos de Alumínio/química , Nanopartículas/química , Neoplasias/diagnóstico , Neoplasias/terapia , Nanomedicina Teranóstica , Animais , Antineoplásicos/farmacologia , Células Hep G2 , Humanos , Luz , Camundongos Endogâmicos C57BL , Nanopartículas/ultraestrutura , Neoplasias/patologia , Fotoquimioterapia , Polietilenoglicóis/química , Espécies Reativas de Oxigênio/química , Temperatura , Distribuição Tecidual/efeitos dos fármacos
4.
Food Chem ; 348: 129021, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-33545643

RESUMO

Lemon essential oils (LEO), as natural bacteriostatic agents, show significant loss in the preparation processes of food packaging materials, therefore, an effective encapsulation of LEO is urgent for realizing the protection. In this study, LEO was absorbed by thermally stable and porous vermiculite (VML) to form LEO/VML complex, which is further coupled with konjac glucomannan-grafted-poly (acrylic acid)/polyvinyl alcohol (KGM-g-PAA/PVA) composite. KGM-g-PAA/PVA bacteriostatic water-absorbing pad was prepared via electrospinning technique, which can minimize the loss of LEO. The VML (1 g) can significantly reduce LEO loss and achieve sustained control LEO release from the pad, which follows the predominant mechanism of Fick diffusion law. The sustained control LEO release from the pad can effectively inhibit the growth of E. coli during storage, thus prolonging shelf life of chilled pork for 3 day. This study suggests that KGM-g-PAA/PVA pad may have a great potential in the field of intelligent packaging.


Assuntos
Silicatos de Alumínio/química , Antibacterianos/química , Antibacterianos/farmacologia , Conservação de Alimentos/métodos , Mananas/química , Óleos Vegetais/química , Álcool de Polivinil/química , Animais , Preparações de Ação Retardada , Escherichia coli/efeitos dos fármacos , Embalagem de Alimentos , Armazenamento de Alimentos , Água/química
5.
Molecules ; 26(2)2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-33435210

RESUMO

This research was aimed at the preparation of a hybrid film based on a layered silicate saponite (Sap) with the immobilized photosensitizer phloxine B (PhB). Sap was selected because of its high cation exchange capacity, ability to exfoliate into nanolayers, and to modify different surfaces. The X-ray diffraction of the films confirmed the intercalation of both the surfactant and PhB molecules in the Sap film. The photosensitizer retained its photoactivity in the hybrid films, as shown by fluorescence spectra measurements. The water contact angles and the measurement of surface free energy demonstrated the hydrophilic nature of the hybrid films. Antimicrobial effectiveness, assessed by the photodynamic inactivation on hybrid films, was tested against a standard strain and against methicillin-resistant bacteria of Staphylococcus aureus (MRSA). One group of samples was irradiated (green LED light; 2.5 h) and compared to nonirradiated ones. S. aureus strains manifested a reduction in growth from 1-log10 to over 3-log10 compared to the control samples with Sap only, and defects in S. aureus cells were proven by scanning electron microscopy. The results proved the optimal photo-physical properties and anti-MRSA potential of this newly designed hybrid system that reflects recent progress in the modification of surfaces for various medical applications.


Assuntos
Silicatos de Alumínio/química , Antibacterianos , Azul de Eosina I/química , Membranas Artificiais , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Antibacterianos/química , Antibacterianos/farmacologia
6.
Carbohydr Polym ; 254: 117307, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33357873

RESUMO

The conditions determining network-forming and aggregation properties of hyaluronan on the mica surface were studied. The hyaluronan was deposited on the surface from aqueous and saline solutions and attached by a bivalent cation. The morphology of the immobilized assemblies was characterized by atomic force microscopy. The experimental results show that the morphology and size of the aggregates as well as the density of the interconnecting fibrillar network, both made of hyaluronan, at the liquid-solid phase interface are determined not only by its molecular weight or concentration in solution, but also by the dissolution conditions and storage time. These findings extend the current state of knowledge about the conformational variability of this biologically important polymer. Understanding the conformational variability is of great importance, as it governs the physiological functions of hyaluronan, as well as its processability and formulations. That in turn determines its usability in different pharmacological and biomaterial applications.


Assuntos
Ácido Hialurônico/química , Polímeros/química , Silicatos de Alumínio/química , Armazenamento de Medicamentos , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Microscopia de Força Atômica/métodos , Estrutura Molecular , Peso Molecular , Solução Salina Hipertônica/química , Solubilidade , Propriedades de Superfície , Água/química
7.
Molecules ; 25(24)2020 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-33321768

RESUMO

In this study, we evaluated the inflammatory responses induced by aluminum silicate (AS) cytotoxicity in rat lungs. The prophylactic effect of propolis extract was evaluated in 60 adult male albino rats. The rats were divided into six groups: (1) a normal, healthy control group; (2) a normal group fed with 200 mL of propolis extract/Kg; (3) a low-dose positive control group injected with 5 mg/kg of AS; (4) a treated group given propolis and a low dose of AS; (5) a high-dose positive control group injected with 20 mg/kg of AS; and (6) a treated group given propolis with a high-dose of AS. At the end of the two-month experiment, the rats' lungs were removed. For each pair of lungs, one portion was subjected to biochemical analysis and the other underwent hematoxylin and eosin (H&E) staining in order to study its histology. The rats that received AS doses displayed significant disorders in their antioxidant contents as well as in their enzymatic activities and their histopathological structures revealed severe damage to their lung tissues. Upon the rats being treated with propolis, the enzymatic and antioxidant contents improved and partial improvements in the lung structures appeared, including minimized congestion, a reduced hemorrhage of blood vessels and preserved bronchioles, alveolar ducts, and alveoli. The prophylactic effectiveness of propolis extract on the cytotoxicity of AS, owing to the antioxidant properties of propolis, were studied.


Assuntos
Silicatos de Alumínio/química , Antioxidantes/química , Antioxidantes/farmacologia , Pulmão/efeitos dos fármacos , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Própole/química , Animais , Biomarcadores , Imuno-Histoquímica , Pulmão/metabolismo , Pulmão/patologia , Estresse Oxidativo/efeitos dos fármacos , Ratos
8.
PLoS One ; 15(12): e0244621, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33378374

RESUMO

Alkali-activated materials (AAMs), sometimes called geopolymers, are eco-friendly cementitious materials with reduced carbon emissions when compared to ordinary Portland cement. However, the availability of most precursors used for AAM production may decline in the future because of changes in industrial sectors. Thus, new precursors must be developed. Recently there has been increased interest in synthetic glass precursors. One major concern with using synthetic glasses is ensuring that they react sufficiently under alkaline conditions. Reactivity is a necessary, although not sufficient, requirement for a suitable precursor for AAMs. This work involves the synthesis, characterization, and estimation of alkaline reactivity of Na-Mg aluminosilicate glasses. Structural characterization showed that replacing Na with Mg led to more depolymerization. Alkaline reactivity studies indicated that, as Mg replaced Na, reactivity of glasses increased at first, reached an optimal value, and then declined. This trend in reactivity could not be explained by the conventional parameters used for estimating glass reactivity: the non-bridging oxygen fraction (which predicts similar reactivity for all glasses) and optical basicity (which predicts a decrease in reactivity with an increase in Mg replacement). The reactivity of the studied glasses was found to depend on two main factors: depolymerization (as indicated by structural characterization) and optical basicity. Depolymerization dominated initially, which led to an increase in reactivity, while the effect of optical basicity dominated later, leading to a decrease in reactivity. Hence, while designing reactive synthetic glasses for alkali activation, structural study of glasses should be given due consideration in addition to the conventional factors.


Assuntos
Silicatos de Alumínio/química , Vidro/química , Magnésio/química , Sódio/química , Álcalis/química , Materiais Biocompatíveis/química , Modelos Moleculares , Conformação Molecular , Difração de Raios X
9.
Chemosphere ; 260: 127566, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32663674

RESUMO

Ball milling was used to fabricate a nanocomposite of 20% hickory biochar (600 °C) and 80% expanded vermiculite (20%-BC/VE). This novel composite adsorbent had much higher removal of As(V) from aqueous solutions than ball-milled biochar and expanded vermiculite. Characterization of these adsorbents showed that the enhanced As(V) adsorption was ascribed to much larger surface area and pore volume (2-6 times), notable changes in crystallinity, activation of cations, and increased functional groups in the nanocomposite compared with the ball-milled products of their pristine counterparts. The As(V) adsorption process by the 20%-BC/VE fitted well with the pseudo-second-order kinetic model (R2= 0.990) and Langmuir isotherm model (R2= 0.989) with a maximum adsorption capacity of 20.1 mg g-1. The 20%-BC/VE best performed at pH about 6. The adsorption efficiency was not sensitive to the competition of NO3-, Cl-, SO42-, as well as the coexistence of humic acid. However, the adsorption capacity for As(V) was significantly reduced by coexisting with PO43-. The 20%-BC/VE composite can potentially serve as a superior low-cost adsorbent for As(V) removal in real-world applications.


Assuntos
Silicatos de Alumínio/química , Arsenicais/isolamento & purificação , Carvão Vegetal/química , Nanocompostos/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Cinética , Poluentes Químicos da Água/análise , Purificação da Água/métodos
10.
Chemosphere ; 258: 127227, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32554003

RESUMO

Eight different types of complexing agents were employed for the development of new biodegradable decontamination solutions that are able to form strippable coatings after they are dispersed and allowed to dry on a variety of surfaces contaminated with 60Co, 133Ba, 137Cs and 241Am radioactive isotopes. The new generation of eco-friendly chelators with superior biodegradability, utilized for the first time in such applications, can easily replace the non-biodegradable and carcinogenic complexing agents that are still in use today, due to their decontamination performances. Furthermore, besides the complexing action over the radionuclides, the solutions contain two types of clays, Bentonite (BT) and Saponite (SP), which have the capacity to adsorb specific ions, improving the decontamination efficiency of the solutions. Our research revealed that it is preferable to replace BT with SP, due to its better dispersibility, thermal stability, next to superior ability to gel and better thermal stability (Miles, 2011). The solutions showed a decontamination factor superior to 95% for 137Cs (on all surfaces), over 90% for 60Co and 133Ba, and more than 72% 241Am (on all surfaces), except for galvanized metal plates, where lower decontamination factors were obtained: over 70% for 133Ba, maximum 41.87% for 241Am and 43.19% for 60Co.


Assuntos
Quelantes/química , Descontaminação/métodos , Substâncias Perigosas/análise , Nanoestruturas/química , Radioisótopos/análise , Adsorção , Silicatos de Alumínio/química , Bentonita/química , Biodegradação Ambiental , Álcool de Polivinil/química , Radioatividade , Soluções , Propriedades de Superfície
11.
Toxicon ; 184: 1-9, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32450144

RESUMO

This paper was designed to analyze the effect of ochratoxin A (OTA) contaminated feed on the growth outcomes, certain serum biochemical, histopathology, and OTA residue in the dorsal muscle, liver, and kidney in Nile tilapia. Also, to improve the drastic effect of OTA through dietary supplementation of hydrated sodium aluminum silicates nanoparticles or nano copper. For performing the present study, 270 fish were randomly allotted into 6 equal groups according to ochratoxin and nanoparticles of hydrated sodium aluminum silicates or copper oxide. The results indicated that supplementation of two levels of both nanoparticles (aluminum silicate or copper) as a mycotoxin adsorbent could prevent ochratoxicosis in Nile tilapia fish. In addition, they maintained optimal growth performance, feed efficiency without bad effect on serum profiles and vital organs function of fish in a dose-dependent manner. Histopathologically, the most interesting finding was the precipitation of calcium salts known as nephrocalcinosis, within the tubules, upon the degenerative tubules and tunica intima and media of the blood vessels in the control positive group. These pathological lesions were mitigated by nanoparticle supplementation. Thus increase the safety of fish products.


Assuntos
Ração Animal/análise , Micotoxinas/química , Nanopartículas/química , Ocratoxinas/química , Silicatos de Alumínio/química , Animais , Ciclídeos , Cobre/química , Suplementos Nutricionais , Contaminação de Alimentos
12.
Chemosphere ; 255: 126942, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32387732

RESUMO

Knowledge of the geochemical behavior of uranium is critical for the safe disposal of radioactive wastes. Biotite, a Fe(II)-rich phyllosilicate, is a common rock-forming mineral and a major component of granite or granodiorite. This work comprehensively studied the sorption of U(VI) on biotite surface with batch experiments and analyzed the uranium speciation with various spectroscopic techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and time-resolved fluorescence spectra (TRFS). Our results indicated that uranyl ions could penetrate into the interlayer of biotite, this ion-exchange process was pH-dependent and only favorable under acidic condition. Instead of precipitation or reduction to uraninite, the TRFS results strongly suggests U(VI) forms surface complexes under the neutral and alkaline condition, though the number and structure of surface species could not be identified accurately. Besides, the oxidation of biotite with peroxide hydrogen showed that structural Fe(II) would have a very low redox reactivity. With leaching experiments, zeta potential analysis and thermodynamics calculation, we discussed the possible reasons for inhibition of U(VI) reduction at the biotite-water interface. Our results may provide insight on interaction mechanism of uranium at mineral-water interface and help us understand the migration behavior of uranium in natural environments.


Assuntos
Silicatos de Alumínio/química , Compostos Ferrosos/química , Urânio/química , Concentração de Íons de Hidrogênio , Troca Iônica , Minerais , Oxirredução , Espectroscopia Fotoeletrônica , Resíduos Radioativos , Dióxido de Silício , Termodinâmica
13.
Chemosphere ; 253: 126754, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32302914

RESUMO

This study sought to analyze the effect of curing temperature on mechanical strength and microstructure of a copper tailing-based geopolymer via scanning electron microscopy (SEM), HCl extraction, nuclear magnetic resonance (NMR), and X-ray diffraction (XRD). The distribution of gel formed in geopolymers tended to be uniform with increasing curing temperature from 25 to 80 °C. Moreover, the percentage of Si sites in C-S-H and N-A-S-H gels increased from 62.08% to 78.94% and more tetrahedral [AlO4] was incorporated into the tetrahedron [SiO4] backbone, leading to an increase of compressive strength from 10.2 to 39.6 MPa. When the curing temperature was increased to 120 °C, the percentage of Si sites in C-S-H and N-A-S-H gel decreased to 69.52%, and the compressive strength decreased to 27.5 MPa. Moderately elevated curing temperature promoted the dissolution of aluminosilicate while curing temperatures above 80 °C hindered it. Excessive curing temperature led to a decrease in the geopolymer alkaline medium.


Assuntos
Silicatos de Alumínio/química , Materiais de Construção/análise , Cobre/química , Resíduos Industriais/análise , Gerenciamento de Resíduos/métodos , Força Compressiva , Microscopia Eletrônica de Varredura , Mineração , Propriedades de Superfície , Temperatura , Difração de Raios X
14.
Braz Oral Res ; 34: e018, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32187304

RESUMO

The objective of this study was to evaluate the influence of hydrofluoric acid (HF) concentration, etching time, and application of phosphoric acid (PA) followed by neutralization with sodium bicarbonate on the bond strength between a feldspar ceramic and resin cement. Thus, 80 blocks (10 x 12 x 2 mm) of glass ceramic (VM - Vita Mark II - Vita Zahnfabrik) were made and randomly assigned to eight groups (n = 10) according to the factors: HF concentration (5 and 10%), etching time (60 and 120 s), and use of phosphoric acid (PA) (with and without). According to the experimental group, 37% PA (Condac, FGM) was applied after HF etching for 60s. Afterwards, samples were immersed in sodium bicarbonate for 1 min then in an ultrasonic bath in distilled water (5 min) for cleaning. After surface bonding treatment, cylinders (Ø = 2 mm; h = 2 mm) of dual resin cement (AllCem / FGM) were made in the center of each block. The samples were then stored in water (37ºC) for 90 days and submitted to the shear bond test (50 KgF, 1 mm/min). Failure analysis was performed by stereomicroscope and scanning electron microscopy. Data (MPa) were analyzed with 3-way ANOVA and Tukey's test. Only the factor "HF concentration" was significant (p = 0.02). Most failures were of cohesive in ceramic (40%) and mixed types (42.5%). The 10% HF resulted in higher shear bond strength value than the 5% HF. Surface cleaning with phosphoric acid followed by sodium bicarbonate and HF time (60 or 120 seconds) did not influence the resin bond strength to feldspar ceramic.


Assuntos
Silicatos de Alumínio/química , Colagem Dentária/métodos , Ácido Fluorídrico/química , Ácidos Fosfóricos/química , Compostos de Potássio/química , Análise de Variância , Porcelana Dentária/química , Teste de Materiais , Metacrilatos/química , Microscopia Eletrônica de Varredura , Valores de Referência , Reprodutibilidade dos Testes , Cimentos de Resina/química , Resistência ao Cisalhamento/efeitos dos fármacos , Silanos/química , Propriedades de Superfície , Fatores de Tempo
15.
Sci Rep ; 10(1): 3351, 2020 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-32099019

RESUMO

An incredible amount of joss fly ash is produced from the burning of Chinese holy joss paper; thus, an excellent method of recycling joss fly ash waste to extract aluminosilicate nanocomposites is explored. The present research aims to introduce a novel method to recycle joss fly ash through a simple and straightforward experimental procedure involving acidic and alkaline treatments. The synthesized aluminosilicate nanocomposite was characterized to justify its structural and physiochemical characteristics. A morphological analysis was performed with field-emission transmission electron microscopy, and scanning electron microscopy revealed the size of the aluminosilicate nanocomposite to be ~25 nm, while also confirming a uniformly spherical-shaped nanostructure. The elemental composition was measured by energy dispersive spectroscopy and revealed the Si to Al ratio to be 13.24 to 7.96, showing the high purity of the extracted nanocomposite. The roughness and particle distribution were analyzed using atomic force microscopy and a zeta analysis. X-ray diffraction patterns showed a synthesis of faceted and cubic aluminosilicate crystals in the nanocomposites. The presence of silica and aluminum was further proven by X-ray photoelectron spectroscopy, and the functional groups were recognized through Fourier transform infrared spectroscopy. The thermal capacity of the nanocomposite was examined by a thermogravimetric analysis. In addition, the research suggested the promising application of aluminosilicate nanocomposites as drug carriers. The above was justified by an enzyme-linked apta-sorbent assay, which claimed that the limit of the aptasensing aluminosilicate-conjugated ampicillin was two-fold higher than that in the absence of the nanocomposite. The drug delivery property was further justified through an antibacterial analysis against Escherichia coli (gram-negative) and Bacillus subtilis (gram-positive).


Assuntos
Silicatos de Alumínio/farmacologia , Cinza de Carvão/farmacologia , Sistemas de Liberação de Medicamentos , Nanocompostos/ultraestrutura , Silicatos de Alumínio/química , Antibacterianos/química , Antibacterianos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Quitosana/química , Cinza de Carvão/química , Escherichia coli/efeitos dos fármacos , Incineração , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanocompostos/química , Tamanho da Partícula , Prata/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
16.
Food Chem Toxicol ; 138: 111187, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32061728

RESUMO

The objective of this study was to determine the immunotoxic effects of deoxynivalenol (DON) in weaning piglets, and potential efficacy of a modified hydrated sodium calcium aluminosilicate (HSCAS) adsorbent to reduce DON toxicity. Four groups of 21-day-old male piglets (n = 7/group) were fed a control diet or diet containing 1.0 or 3.0 mg DON/kg, or 3.0 mg DON/kg plus 0.05% modified HSCAS for 4 weeks. Compared to the control, the DON diets decreased serum porcine circovirus antibody titer and the dermal hypersensitivity response to OVA at day 21 or 28. DON also induced focal necrosis and proliferation of cortical lymphocytes and apoptosis and increased the total antioxidant capacity and reduced glutathione, protein carbonyl concentrations in thymus. DON increased thymus mRNA, protein and (or) enzyme levels, cytokines (IL-6, IL-10, and TNF-α) and apoptosis-related genes (Caspase-3), while hematopoietic cell kinase (HCK) decreased. Intriguingly, the modified HSCAS alleviated the DON-induced changes on serum antibody titer, and thymic histopathology, apoptosis, redox status, inflammation and apoptosis signaling. In conclusion, these findings help to explain the toxic effects and mechanisms of DON and demonstrated the modified HSCAS adsorbent could be used to reduce the toxicity of DON in weaning piglets.


Assuntos
Imunidade Adaptativa , Silicatos de Alumínio/química , Tricotecenos/toxicidade , Ração Animal/análise , Animais , Animais Recém-Nascidos , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Caspase 3/genética , Caspase 3/metabolismo , Catalase/metabolismo , Circovirus/imunologia , Citocinas/sangue , Dieta/veterinária , Contaminação de Alimentos/análise , Glutationa/metabolismo , Masculino , Malondialdeído/metabolismo , Proteínas Proto-Oncogênicas c-hck/genética , Proteínas Proto-Oncogênicas c-hck/metabolismo , Baço/efeitos dos fármacos , Baço/metabolismo , Superóxido Dismutase/metabolismo , Suínos , Timo/efeitos dos fármacos , Timo/metabolismo , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo , Vacinas Virais/imunologia , Desmame
17.
Molecules ; 25(4)2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32053961

RESUMO

Preparation of aluminosilicate ferrierite (FER) zeolite nanosheets with controllable thickness in the presence of a sole organic ammonium is attractive, but still challenging. In this report, with the employment of N,N-diethyl-cis-2,6-dimethylpiperidinium (DMP) as both a structure directing agent and crystal growth inhibitor, aluminosilicate FER zeolite nanosheets, with a variety of crystal thicknesses, ranging from 6 to 200 nm, are successfully synthesized under hydrothermal conditions. Very interestingly, the amount of DMP in the starting gel is the key factor for crystal thickness control of aluminosilicate FER zeolite nanosheets. The obtained FER products, with different thicknesses, are well characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), N2 sorption, thermogravimetric analysis (TG), inductively coupled plasma (ICP), and magic angle spinning nuclear magnetic resonance (MAS NMR) techniques. This simple strategy might provide a novel avenue for the synthesis of other zeolite nanosheets with controllable thickness.


Assuntos
Silicatos de Alumínio/química , Nanoestruturas/química , Zeolitas/química , Técnicas de Química Sintética , Espectroscopia de Ressonância Magnética , Nanoestruturas/ultraestrutura , Difração de Raios X
18.
Chemphyschem ; 21(3): 188-193, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-31912640

RESUMO

Tip-enhanced Raman spectroscopy (TERS) is a promising technique for structural studies of biological systems and biomolecules, owing to its ability to provide a chemical fingerprint with sub-diffraction-limit spatial resolution. This application of TERS has thus far been limited, due to difficulties in generating high field enhancements while maintaining biocompatibility. The high sensitivity achievable through TERS arises from the excitation of a localized surface plasmon resonance in a noble metal atomic force microscope (AFM) tip, which in combination with a metallic surface can produce huge enhancements in the local optical field. However, metals have poor biocompatibility, potentially introducing difficulties in characterizing native structure and conformation in biomolecules, whereas biocompatible surfaces have weak optical field enhancements. Herein, a novel, biocompatible, highly enhancing surface is designed and fabricated based on few-monolayer mica flakes, mechanically exfoliated on a metal surface. These surfaces allow the formation of coupled plasmon enhancements for TERS imaging, while maintaining the biocompatibility and atomic flatness of the mica surface for high resolution AFM. The capability of these substrates for TERS is confirmed numerically and experimentally. We demonstrate up to five orders of magnitude improvement in TERS signals over conventional mica surfaces, expanding the sensitivity of TERS to a wide range of non-resonant biomolecules with weak Raman cross-sections. The increase in sensitivity obtained through this approach also enables the collection of nanoscale spectra with short integration times, improving hyperspectral mapping for these applications. These mica/metal surfaces therefore have the potential to revolutionize spectromicroscopy of complex, heterogeneous biological systems such as DNA and protein complexes.


Assuntos
Silicatos de Alumínio/química , Materiais Biocompatíveis/química , Ouro/química , Microscopia de Força Atômica/instrumentação , DNA/análise , Microscopia de Força Atômica/métodos , Análise Espectral Raman/métodos , Ressonância de Plasmônio de Superfície/métodos
19.
Carbohydr Polym ; 230: 115600, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887872

RESUMO

Kinetics of chitosan depolymerization were studied in dilute acetic acid solution, in presence of H-Mordenite (H-MOR). Rate constants for chitosan depolymerization were determined by measurement of molecular weight, using Gel permeation Chromatography (GPC). Depolymerization rate of chitosan was altered in presence of an acidic, porous material like H-MOR. Maximum concentration of H-MOR studied during process led to minimal increase in energy of activation, from 20.54 kJ/moL to 23.25 kJ/moL. Infra-red spectroscopy, adsorption studies and rheological assessment indicated adsorption /grafting of chitosan onto porous H-MOR surface as the possible mechanism for facilitation of the depolymerization process. Under extreme conditions investigated during process optimization, H-MOR resulted in a three-fold reduction in 5-Hydroxy Methyl Furfural (5-HMF) formation and over ten times decrease in glucosamine content, as compared to reactions conducted without H-MOR. Therefore, presence of H-MOR is imperative to cleave chitosan in controlled manner and obtain products of desired molecular weight, with fewer impurities.


Assuntos
Silicatos de Alumínio/química , Quitosana/análogos & derivados , Ácidos/química , Química Verde/métodos , Cinética , Polimerização
20.
Chemosphere ; 245: 125643, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31877460

RESUMO

The cationic surfactants cetyltrimethylammonium bromide (CTAB) and cetylpyridinium chloride (CPC) can exert inhibitory effects on micro-organisms responsible for their biodegradation. However, under environmentally relevant exposure scenarios the presence of and sorption to organic and inorganic matter can lead to significant reduction of inhibitory effects. In our studies we investigated silica gel and seven clays as inert sorbents to mitigate these inhibitory effects in a 28 day manometric respirometry biodegradation test. CTAB was not inhibitory to the used inoculum, but we did observe that seven out of eight sorbents increased maximum attainable biodegradation, and four out of eight decreased the lag phase. The strongly inhibitory effect of CPC was successfully mitigated by most sorbents, with five out of eight allowing >50% biodegradation within 28 days. Results further indicate that bioaccessibility of the sorbed fractions in the stirred manometric test systems was higher than in calmly shaken headspace test systems. Bioaccessibility might also be limited depending on characteristics of test chemical and sorbent type, with montmorillonite and bentonite apparently providing the lowest level of bioaccessibility with CPC. Clay sorbents can thus be used as environmentally relevant sorbents to mitigate potential inhibitory effects of test chemicals, but factors that impede bioaccessibility should be considered. In addition to apparently increased bioaccessibility due to stirring, the automated manometric respirometry test systems give valuable and highly cost-effective insights into lag phase and biodegradation kinetics; information that is especially relevant for test chemicals of gradual biodegradability.


Assuntos
Biodegradação Ambiental , Argila/química , Desinfetantes/química , Adsorção , Silicatos de Alumínio/química , Bentonita/química , Cátions , Cetilpiridínio , Tensoativos/química
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