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1.
Int J Biol Macromol ; 171: 514-526, 2021 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-33428954

RESUMO

The Alginate-Neusilin US2 micro-composite (MC) beads were fabricated and optimized for oral delivery of hesperidin (HES). A 32 full factorial design encompassing independent variables (factors) such as the concentration of sodium alginate (X1), and Neusilin US2 (X2) and dependant variables (response) such as particle size (Y1), entrapment efficiency (Y2), and swelling degree (Y3). Nine batches were prepared by formulation design employing statistical software JMP 13.2.1. The multiple regression analysis (MLRA) was carried to explore the influence of factor over responses. Further, a prediction profiler was used to trace the optimum concentration of factors based on desirable responses. The optimized beads (OF) were characterized for their morphology and size by motic microscopy and scanning electron microscopy. In vitro release, kinetic studies were performed in simulated gastric and intestinal fluids. In vivo pharmacokinetic studies revealed better absorption of HES from optimized beads (OF) compared to HES suspension which could be due to the prevention of acidic degradation of HES in the stomach. The estimated shelf life of OF formulation was found to be 3.86 years suggested better stability after fabrication. In a nutshell, the developed micro-composite beads of HES could be a better alternative for promising oral sustained delivery of HES.


Assuntos
Alginatos/química , Compostos de Alumínio/química , Portadores de Fármacos/química , Suco Gástrico/metabolismo , Hesperidina/administração & dosagem , Compostos de Magnésio/química , Silicatos/química , Administração Oral , Alginatos/administração & dosagem , Alginatos/farmacocinética , Compostos de Alumínio/administração & dosagem , Compostos de Alumínio/farmacocinética , Animais , Líquidos Corporais/metabolismo , Técnicas de Química Analítica , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/farmacocinética , Composição de Medicamentos , Liberação Controlada de Fármacos , Estabilidade de Medicamentos , Hesperidina/farmacocinética , Intestinos , Cinética , Compostos de Magnésio/administração & dosagem , Compostos de Magnésio/farmacocinética , Masculino , Microscopia Eletrônica de Varredura , Microesferas , Tamanho da Partícula , Ratos Wistar , Silicatos/administração & dosagem , Silicatos/farmacocinética
2.
Niger J Clin Pract ; 23(8): 1068-1072, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32788483

RESUMO

Aims: The aim of this study was to compare the influence of operators on the microhardness and compressive strength of mineral trioxide aggregate (MTA). Materials and Methods: Forty dental specialists were asked to prepare a series of MTA samples. The tested material was ProRoot MTA (DentsplyMaillefer, Switzerland). Each participant prepared one sample to a consistency they considered acceptable for use in practice (improvised group) and another one according to the manufacturer's recommended water-to-powder (WP) ratio (pre-weighed group). The samples were incubated at 37°C and 95% humidity for 4 days. Parameters evaluated in this study were microhardness and compressive strength. Results: Operators mixed MTA samples with varying WP ratios. However, there was no significant difference between the microhardness and compressive strength values of MTA samples between the improvised, the pre-weighed and the control groups. MTA was mixed in a thicker consistency than the manufacturers recommended ratio (0.33) by 62.5% of the operators. Conclusion: According to the results of this study, even though the WP ratios that were utilized in the clinical setting vary, microhardness and compressive strength values of MTA was not significantly affected.


Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Força Compressiva , Teste de Materiais/métodos , Óxidos/química , Materiais Restauradores do Canal Radicular , Silicatos/química , Estudos de Casos e Controles , Combinação de Medicamentos , Dureza , Humanos , Água
3.
J Vis Exp ; (160)2020 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-32658181

RESUMO

This protocol demonstrates a method for graphene-assisted quick growth and coalescence of AlN on nano-pattened sapphire substrate (NPSS). Graphene layers are directly grown on NPSS using catalyst-free atmospheric-pressure chemical vapor deposition (APCVD). By applying nitrogen reactive ion etching (RIE) plasma treatment, defects are introduced into the graphene film to enhance chemical reactivity. During metal-organic chemical vapor deposition (MOCVD) growth of AlN, this N-plasma treated graphene buffer enables AlN quick growth, and coalescence on NPSS is confirmed by cross-sectional scanning electron microscopy (SEM). The high quality of AlN on graphene-NPSS is then evaluated by X-ray rocking curves (XRCs) with narrow (0002) and (10-12) full width at half-maximum (FWHM) as 267.2 arcsec and 503.4 arcsec, respectively. Compared to bare NPSS, AlN growth on graphene-NPSS shows significant reduction of residual stress from 0.87 GPa to 0.25 Gpa, based on Raman measurements. Followed by AlGaN multiple quantum wells (MQWS) growth on graphene-NPSS, AlGaN-based deep ultraviolet light-emitting-diodes (DUV LEDs) are fabricated. The fabricated DUV-LEDs also demonstrate obvious, enhanced luminescence performance. This work provides a new solution for the growth of high quality AlN and fabrication of high performance DUV-LEDs using a shorter process and less costs.


Assuntos
Óxido de Alumínio/química , Grafite/química , Nanoestruturas/química , Semicondutores , Raios Ultravioleta , Compostos de Alumínio/química , Catálise , Gálio/química , Gases/química , Luminescência , Volatilização
4.
Endodoncia (Madr.) ; 38(1): 28-43, jun. 2020. ilus, tab, graf
Artigo em Espanhol | IBECS | ID: ibc-199207

RESUMO

OBJETIVO: Los materiales que se emplean para procedimientos dentales en los que el material contacta directamente con el tejido pulpar y tejidos periodontales han de cumplir una serie de propiedades, entre ellas la biocompatibilidad. A su vez, han de ser materiales que eviten el paso de fluidos y microorganismos con el fin de preservar las condiciones óptimas de los tejidos. El objetivo de esta revisión sistemática fue evaluar la porosidad de los diferentes cementos de agregado trióxido mineral (MTA). MÉTODO: Dos investigadores realizaron búsquedas avanzadas en: PubMed Central, PubMed, Web of Science, Scopus, Cochrane Li-brary, Science Direc y Science Database (Proquest) siguiendo los criterios PRISMA. Los criterios de inclusión contemplaban los es-tudios in vitro, publicados en inglés desde enero de 1993 hasta abril de 2019, que analizaran y midieran la porosidad del MTA. Se excluyeron los estudios in vivo, piloto, editoriales, cartas, revisiones sistemáticas, reseñas literarias, resúmenes de conferencias y trabajos de fin de grado. RESULTADOS: Un total de 853 artículos resultó de la búsqueda inicial, de los que solo 19 pasaron los criterios de inclusión, exclusión y el análisis del riesgo de sesgo. En ellos, se analizan distintas técnicas de condensación del MTA, radiopacificadores, sustratos, etc., en busca de materiales que presenten menor porosidad. CONCLUSIONES: La elevada heterogeneidad de los estudios sobre porosidad y el hecho de que éstos no estén estandarizados, pue-de condicionar la validez externa o generalización de los resultados entre los distintos investigadores para un mismo material y procedimiento. En los estudios que realizan una comparación entre varios materiales, concluyen que tanto MTA ProRoot® y Bio-dentineTM obtuvieron mejores resultados en cuanto a porosidad. Número de solicitud (PROSPERO): 124340


OBJECTIVE: Materials used for dental procedures in which the material directly contacts the pulp and periodontal tissues must have a series of characteristics, such as biocompatibility. Equally, they must be materials that prevent the passage of fluids and microorganisms aiming at keeping the optimal conditions of the tissues intact. The objective of this systematic review was to evaluate the porosity of the different cements of mineral trioxide aggregate (MTA). METHOD: Two researchers conducted advanced searches in: PubMed Central, PubMed, Web of Science, Scopus, Cochrane Library, ScienceDirect and ScienceDatabase (Proquest) following the PRISMA criteria. Inclusion criteria took into account in vitro studies, published in English from January 1993 to April 2019, to analyse and measure the porosity of the MTA. In vivo and pilot studies were excluded, as well as editorials, letters, systematic reviews, literary reviews, conference abstracts and dissertations. RESULTS: A total of 853 articles resulted from the initial search, of which only 19 met the criteria for inclusion, exclusion and analysis of the risk of bias. In them, different condensation techniques of the MTA, radiopacifiers, substrates, etc., are analysed in quest of materials with less porosity. CONCLUSIONS: The high heterogeneity of the studies on porosity and the fact that they are not standardised, can condition the external validity or generalisation of the results among the different researchers for the same material and procedure. In the studies that make a comparison between several materials, they conclude that both MTA ProRoot® and BiodentineTM obtained better outcomes in terms of porosity as compared with other marketed brands. Application number (PROSPERO): 124340


Assuntos
Humanos , Cimentos Dentários/química , Materiais Restauradores do Canal Radicular/química , Compostos de Cálcio/química , Compostos de Alumínio/química , Materiais Restauradores do Canal Radicular/uso terapêutico , Cimentos Dentários/uso terapêutico , Compostos de Cálcio/uso terapêutico , Compostos de Alumínio/uso terapêutico , Materiais Biocompatíveis/química , Materiais Biocompatíveis/uso terapêutico , Porosidade
5.
BMC Oral Health ; 20(1): 37, 2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-32013975

RESUMO

BACKGROUND: The present study compares the apical microleakage of three different root-end filling materials in which the retrograde cavity is prepared by two different burs. METHODS: Eighty extracted single rooted maxillary and mandibular premolars were taken. Root canal treatment was completed. Apical 3 mm of all the teeth were resected with diamond disk. The tooth were divided into four groups with two subgroups for each group containing 10 tooth (N = 10) as: Group IA (Negative Control and IB (Positive Control); Group IIA and IIB: Prepared with round carbide bur and round diamond bur respectively, filled with GIC; Group IIIA and IIIB: Prepared with round carbide bur and round diamond bur respectively, filled with MTA; Group IVA and IVB: Prepared with round carbide bur and round diamond bur, filled with Biodentine. After applying two coats of nail varnish leaving apical 3 mm (except for negative control group) all teeth were immersed in 2% methylene blue for 3 days and again in 65% nitric acid for next 3 days for extraction of dye. The obtained solution was then transferred to eppendorf tube and centrifuged in microcentrifuges at 14,000 revolution per minutes (RPM) for 5 min. Optical density or absorbance of the supernatant solution was measured with UV spectrophotometer at 550 nm. RESULTS: The absorbance of the supernatant solution after dye extraction is decreasing in the order of positive control> GIC > MTA > Biodentine> negative control group. The significant difference was observed between GIC and MTA (p = 0.0001) and GIC and Biodentine (p = 0.0001) with two different burs but statistically non-significant difference was observed between MTA and Biodentine with Carbide bur (p = 0.127) and Diamond bur (p = 0.496) respectively. CONCLUSIONS: Within the limitations of the present study, it can be concluded that Biodentine and MTA showed less microleakage as compared to GIC. There is no significant difference between mean microleakage of MTA and Biodentine. However, the mean OD of the Biodentine was least of all evaluated materials. Preparation of the root-end using round carbide bur as well as round diamond burs showed comparable microleakage for all three filling materials.


Assuntos
Compostos de Alumínio/farmacologia , Apicectomia/métodos , Compostos de Cálcio/farmacologia , Cimentos Dentários/química , Infiltração Dentária/prevenção & controle , Óxidos/química , Materiais Restauradores do Canal Radicular/farmacologia , Silicatos/farmacologia , Ápice Dentário/efeitos dos fármacos , Compostos de Alumínio/química , Compostos de Cálcio/química , Infiltração Dentária/diagnóstico , Combinação de Medicamentos , Humanos , Pemetrexede , Materiais Restauradores do Canal Radicular/química , Silicatos/química , Resultado do Tratamento
6.
Dalton Trans ; 49(6): 1947-1954, 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-31976498

RESUMO

A series of solid solution CaAl12-xGaxO19:Mn4+ phosphors were prepared via a high-temperature solid-state reaction. Their structural properties were characterized by X-ray diffraction (XRD) and the luminescence was investigated via photoluminescence spectra. The obtained CaAl12-xGaxO19:Mn4+ phosphor has a strong broad excitation band in the range of 250-550 nm, which can be easily excited by the UV, NUV and blue light, and a broad emission band centered at 655 nm between 600 nm and 800 nm due to the 2Eg → 4A2g transition of the Mn4+ ion. The PL spectra indicate that the intensity of CaAl12O19:Mn4+ can be enhanced when the Ga3+ concentration equals 1. Furthermore, the element mapping, optical properties, thermal stability, fluorescence lifetime and CIE chromaticity reveal that the CaAl12-xGaxO19:Mn4+ phosphors can be considered as potential candidates in indoor plant cultivation.


Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Gálio/química , Substâncias Luminescentes/química , Manganês/química , Iluminação/métodos , Luminescência , Medições Luminescentes , Desenvolvimento Vegetal , Difração de Raios X
7.
Eur J Pharm Biopharm ; 148: 126-133, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31982576

RESUMO

Polymeric film coatings based on quaternary polymethacrylates (QPMs, e.g. Eudragits®) are frequently used for controlled release applications. However, their considerable sticking tendency is a major drawback in practice. In this study, different amounts of magnesium aluminum silicate (MAS) were added to the film coatings in order to overcome this hurdle. MAS is negatively charged and can electrostatically interact with the positively charged QPM. Different types of tablet cores were coated with aqueous Eudragit® RL 30D dispersions, optionally containing varying amounts of MAS. Dynamic changes in the wet mass of the systems as well as drug release upon exposure to 0.1 M HCl and phosphate buffer pH 6.8 were monitored. Propranolol HCl, acetaminophen, and diclofenac sodium were used as cationic, nonionic and anionic model drugs. The tablets were optionally cured for 12 h at 45 or 60 °C. Importantly, the addition of MAS to aqueous Eudragit® RL 30D dispersion substantially reduced the films' stickiness and led to stable inner coating structures, even without curing. Desired drug release rates can be adjusted by varying the QPM:MAS ratio and coating level.


Assuntos
Compostos de Alumínio/química , Excipientes/química , Compostos de Magnésio/química , Polímeros/química , Silicatos/química , Acetaminofen/química , Química Farmacêutica , Preparações de Ação Retardada , Diclofenaco/química , Liberação Controlada de Fármacos , Propranolol/química , Comprimidos , Temperatura
8.
Nat Commun ; 11(1): 326, 2020 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-31949147

RESUMO

Bioinspired electronics are rapidly promoting advances in artificial intelligence. Emerging AI applications, e.g., autopilot and robotics, increasingly spur the development of power devices with new forms. Here, we present a strain-controlled power device that can directly modulate the output power responses to external strain at a rapid speed, as inspired by human reflex. By using the cantilever-structured AlGaN/AlN/GaN-based high electron mobility transistor, the device can control significant output power modulation (2.30-2.72 × 103 W cm-2) with weak mechanical stimuli (0-16 mN) at a gate bias of 1 V. We further demonstrate the acceleration-feedback-controlled power application, and prove that the output power can be effectively adjusted at real-time in response to acceleration changes, i.e., ▵P of 72.78-132.89 W cm-2 at an acceleration of 1-5 G at a supply voltage of 15 V. Looking forward, the device will have great significance in a wide range of AI applications, including autopilot, robotics, and human-machine interfaces.


Assuntos
Inteligência Artificial , Reflexo/fisiologia , Robótica/instrumentação , Robótica/métodos , Transistores Eletrônicos , Compostos de Alumínio/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Elétrons , Gálio/química , Humanos
9.
Molecules ; 25(2)2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31947638

RESUMO

We demonstrate that supercycles of previously introduced two-fold symmetry dipolar recoupling schemes may be utilized successfully in homonuclear correlation nuclear magnetic resonance (NMR) spectroscopy for probing proximities among half-integer spin quadrupolar nuclei in network materials undergoing magic-angle-spinning (MAS). These (SR2 2 1 ) M , (SR2 4 1 ) M , and (SR2 8 1 )M recoupling sequences with M = 3 and M = 4 offer comparably efficient magnetization transfers in single-quantum-single-quantum (1Q-1Q) correlation NMR experiments under moderately fast MAS conditions, as demonstrated at 14.1 T and 24 kHz MAS in the contexts of 11 B NMR on a Na 2 O-CaO-B 2 O 3 -SiO 2 glass and 27 Al NMR on the open framework aluminophosphate AlPO-CJ19 [(NH 4 ) 2 Al 4 (PO 4 ) 4 HPO 4 · H 2 O]. Numerically simulated magnetization transfers in spin-3/2 pairs revealed a progressively enhanced tolerance to resonance offsets and rf-amplitude errors of the recoupling pulses along the series (SR2 2 1 ) M < (SR2 4 1 ) M < (SR2 8 1 )M for increasing differences in chemical shifts between the two nuclei. Nonetheless, for scenarios of a relatively minor chemical-shift dispersions ( ≲ 3 kHz), the (SR2 2 1 )M supercycles perform best both experimentally and in simulations.


Assuntos
Algoritmos , Compostos de Alumínio/química , Simulação por Computador , Vidro/química , Espectroscopia de Ressonância Magnética/métodos , Imãs , Modelos Teóricos , Teoria Quântica
10.
J Appl Oral Sci ; 28: e20190105, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31800873

RESUMO

Calcium aluminate cement (CAC) has been highlighted as a promising alternative for endodontic use aiming at periapical tissue repair. However, its effects on dental pulp cells have been poorly explored. OBJECTIVE: This study assessed the impact of calcium chloride (CaCl2) and bismuth oxide (Bi2O3) or zinc oxide (ZnO) additives on odontoblast cell response to CAC. METHODOLOGY: MDPC-23 cells were exposed for up to 14 d: 1) CAC with 2.8% CaCl2 and 25% ZnO (CACz); 2) CAC with 2.8% CaCl2 and 25% Bi2O3 (CACb); 3) CAC with 10% CaCl2 and 25% Bi2O3 (CACb+); or 4) mineral trioxide aggregate (MTA), placed on inserts. Non-exposed cultures served as control. Cell morphology, cell viability, gene expression of alkaline phosphatase (ALP), bone sialoprotein (BSP), and dentin matrix protein 1 (DMP-1), ALP activity, and extracellular matrix mineralization were evaluated. Data were compared using ANOVA (α=5%). RESULTS: Lower cell density was detected only for MTA and CACb+ compared with Control, with areas showing reduced cell spreading. Cell viability was similar among groups at days one and three (p>0.05). CACb+ and MTA showed the lowest cell viability values at day seven (p>0.05). CACb and CACb+ promoted higher ALP and BSP expression compared with CACz (p<0.05); despite that, all cements supported ALP activity. Matrix mineralization were enhanced in CACb+ and MTA. CONCLUSION: In conclusion, CAC with Bi2O3, but not with ZnO, supported the expression of odontoblastic phenotype, but only the composition with 10% CaCl2 promoted mineralized matrix formation, rendering it suitable for dentin-pulp complex repair.


Assuntos
Compostos de Alumínio/química , Compostos de Alumínio/farmacologia , Compostos de Cálcio/química , Compostos de Cálcio/farmacologia , Cimentos Dentários/química , Cimentos Dentários/farmacologia , Polpa Dentária/citologia , Polpa Dentária/efeitos dos fármacos , Fosfatase Alcalina/análise , Fosfatase Alcalina/efeitos dos fármacos , Animais , Bismuto/química , Bismuto/farmacologia , Cloreto de Cálcio/química , Cloreto de Cálcio/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Combinação de Medicamentos , Expressão Gênica/efeitos dos fármacos , Teste de Materiais , Camundongos , Odontoblastos/efeitos dos fármacos , Óxidos/química , Óxidos/farmacologia , Reprodutibilidade dos Testes , Silicatos/química , Silicatos/farmacologia , Fatores de Tempo , Óxido de Zinco/química , Óxido de Zinco/farmacologia
11.
Food Chem ; 305: 125456, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31525594

RESUMO

This work developed a new technique and an application of an existing approach to determine sodium in food sauces, involving enthalpimetric reactions in the infrared. Infrared Thermometric Titration (TT-IR) was utilized, with simple analyzers and low-cost measurement instruments for the acquisition of the surface temperature generated in the sodium precipitation reaction and development of software for the acquisition and processing of data using Raspberry Pi. The sodium was also quantified by Thermal Infrared Enthalpimetry (TIE), a recently developed technique. The rapid and simple quantification of sodium by the TT-IR and TIE showed the possibility of a selective reaction for sodium, using aluminum nitrate, potassium and ammonium fluoride in an acid medium, with reduction of the reagents and without the digestion step in the sample preparation. The results acquired through TT-IR and TIE corroborated the Flame Atomic Emission Spectrometry (FAES) with 96 to 103% and 95 to 102%, respectively.


Assuntos
Análise de Alimentos/métodos , Raios Infravermelhos , Sódio/análise , Produtos Vegetais/análise , Compostos de Alumínio/química , Limite de Detecção , Nitratos/química , Sódio/química , Espectrofotometria Atômica , Temperatura , Termometria/métodos
12.
Technol Health Care ; 28(1): 35-44, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31104033

RESUMO

BACKGROUND: Clinicians routinely encounter the endodontically treated teeth with wide flared canals and mineral trioxide aggregate (MTA) repair on the canal wall. OBJECTIVE: To assess the effect of customized glass reinforced composite (FRC) post and reshaped root canal along with different acid etching protocol of MTA surface on push-out bond strength (PBS) in flared, MTA repaired root canal. METHODS: Ninety recently extracted single-rooted premolar teeth were sequentially subjected to root canal obturation, post space preparation, flaring, and MTA application. The samples were randomly divided into 3 groups of control (no relining or reshaping), customized FRC post by relining with self-adhesive resin cement and reshaping the canal with flowable composite. Each group was subdivided into 3 subgroups (n= 10) as no surface treatment, 37% H3PO4 and 19% EDTA etching of MTA surface. Teeth samples cemented with FRC post were sectioned into 2 mm and push-out testing. RESULTS: Control group had the lowest PBS at 1.988 N. The PBS values for the groups with customized post relining were 8.489 N, 8.888 N and 7.911 N for control, H3PO4 etch and EDTA etch. The corresponding PBS values for root canal reshaping were 7.323 N, 8.318 N and 7.785 N. CONCLUSIONS: Customized FRC post with 37% H3PO4 etching is advised for the flared and MTA repaired root canals.


Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Materiais Dentários/química , Vidro/química , Óxidos/química , Preparo de Canal Radicular/métodos , Silicatos/química , Combinação de Medicamentos , Humanos
13.
J Pharm Biomed Anal ; 179: 113004, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31791835

RESUMO

Pellets with an immobilized enzyme (acetyl- or butyrylcholinesterase) are the up-to-date type of carriers used for the detection of nerve agents (soman, sarin, tabun, VX, Novichok) and other cholinesterase inhibitors such as organophosphate and carbamate insecticides (parathion, malathion). They are used in the glass detection tubes as a layer containing the enzyme together with the second layer, which contains a colorimetric reagent and substrate. The detection method is based on the visually or spectrophotometrically observable Ellman's reaction, which develops a yellow color in the absence of the cholinesterase inhibitor; otherwise, the detector preserves its original color (preferably white). This reaction occurs very fast and has a high sensitivity to nerve agents but it suffers from an indistinctive color transition from white to yellow. In the presented study, a new approach with the use of the synergic effect of magnesium aluminometasilicate with a high surface area marketed as Neusilin®US2 and a protective semipermeable Eudragit® RL layer was utilized. The prepared pellets have been evaluated for their properties such as the activity of the enzyme, intensity of the developed yellow color, sensitivity to cholinesterase inhibitor physostigmine, which acts as a nerve agent simulant, and physical parameters such as hardness, pycnometric density and sphericity. After the initial evaluation, all samples underwent a stability test under three different storage conditions for 24 months during which they were evaluated at given time points (0, 3, 6, 12 and 24 months). It was found that the prepared samples achieved a much higher intensity of developed yellow color than in the published studies while maintaining similar or better sensitivity, speed of detection and suitable physico-chemical properties.


Assuntos
Inibidores da Colinesterase/análise , Agentes Neurotóxicos/análise , Acetilcolinesterase/química , Compostos de Alumínio/química , Butirilcolinesterase/química , Colorimetria/métodos , Enzimas Imobilizadas/química , Compostos de Magnésio/química , Polímeros/química , Silicatos/química , Fatores de Tempo
14.
J Mater Sci Mater Med ; 31(1): 10, 2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31873807

RESUMO

Calcium aluminate cement (CAC) as a biomaterial has been evaluated for its physical, mechanical and biocompatibility properties. Furthermore, the application of CAC for bone repair is due to its composition and coefficient of thermal expansion, which is similar to that of human bone. Thus, the aim of this study was to evaluate compositions of CAC-based blends as substitutes for bone defects. Five compositions of blends (alumina, zirconia, hydroxyapatite, tricalcium phosphate, chitosan), in addition to the base cement consisting of homogeneous CAC were evaluated as a substitute for bone repair. Additionally, the monotypic biofilm formation was assessed. Creation of a monocortical bone defect was performed on the femurs of rats, which were randomly filled with the different materials. The polymethylmethacrylate (PMMA) group was used as a control. All the animals were euthanized 04 weeks after the surgery procedure. Subsequently, computerized microtomography, histological and histomorphometric analyses were performed to verify the bone repair. To evaluate the formation of biofilms, reference strains of Staphylococcus aureus, Streptococcus mutans and Pseudomonas aeruginosa were cultured on the samples, and the biofilm formed was quantified by the MTT method. In the microtomography and histomorphometry results, it was observed that the blends exhibited better results than the control group, with statistically significant differences (p < 0.05) for alumina and zirconia blends. In the biofilm formation, a statistical difference (p < 0.05) in general was observed between the alumina blends and the control group (p < 0.05). It was concluded that CAC-based blends with alumina and zirconia are promising for use in fillings for bone repair.


Assuntos
Compostos de Alumínio/química , Materiais Biocompatíveis , Biofilmes , Cimentos para Ossos/química , Osso e Ossos/lesões , Compostos de Cálcio/química , Animais , Teste de Materiais , Ratos , Engenharia Tecidual
15.
Int J Mol Sci ; 20(22)2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31739485

RESUMO

The menace of antimicrobial resistance continues to increase and hence the need to discover new antibiotics, especially alternative and effective sources such as hybrid organic-inorganic, organic-organic materials, and other combinations. In this study, an antimicrobial hybrid supra-nano material was prepared by the bi-titration synthesis method of chitosan (CS) and ZnAl layered double hydroxide. Fourier-transform infrared spectrometer (FTIR), thermogravimetric and differential thermal gravimetric (TGA/DTG), ultraviolet-visible (UV-Vis), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses indicated that the ZnAl/CS hybrid exhibited low crystallinity with high thermal stability. The results of ZnAl/CS characterization showed the characteristic properties of the individual components ZnAl and CS, indicating a successful preparation of the ZnAl/CS hybrid. The antibacterial tests revealed that the ZnAl/CS hybrid possessed an enhanced antimicrobial effect against both Escherichia coli (E. coli, MTCC 739) and Penicilliumcyclopium (P. cyclopium, AS 3.4513). Under the central composite design (CCD) of the response surface methodology (RSM) tool, the parameters of the hybrid synthesis reaction were optimized and the result obtained was as follows: reaction pH was 11.3, reagent Zn/Al ratio was 3.27, and chitosan concentration was 1.07 g/L. After optimization, it was found that the antibacterial activity of ZnAl/CS was strengthened against E. coli as evidenced by a widening of the inhibition zone of about 41.6%. The antibacterial activity of ZnAl/CS was mainly due to the reactivation of the antibacterial activity of CS associated with the release of Zn2+ and Al3+ metal ions in addition to ZnO, Al2O3, and ZnAl2O4 compounds resulting from the method of preparation.


Assuntos
Compostos de Alumínio/química , Antibacterianos/química , Antibacterianos/farmacologia , Quitosana/química , Nanocompostos/química , Compostos de Zinco/química , Testes de Sensibilidade Microbiana , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Difração de Raios X
16.
Chem Pharm Bull (Tokyo) ; 67(10): 1152-1159, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31582635

RESUMO

Melt adsorption is a manufacturing method that offers precise control of particle size distribution of granules and circumvents the disadvantages of conventional melt granulation. However, drug release from particles adsorbed with hydrophobic materials has not been fully investigated, and there are missing details as to whether particles manufactured by this technique can be applied to orally disintegrating tablets (ODT). In this report, we aimed to optimize process parameters and formulation to manufacture ODT containing melt adsorption-particles with the specific characteristic of sustained release. Melt adsorption particles containing Neusilin US2 as the adsorbent were prepared by using various waxes to determine the most suitable material for controlled release formulation. Glycerol fatty acid ester (Poem TR-FB: TR-FB) was the optimal wax examined because of its drug release pattern and tabletability. We then optimized manufacturing conditions by examining granulation time, disintegrant amount per tablet and compression force on the tablet for ODT that meet the criteria of controlled drug release, tensile strength and disintegration of the tablet. Multiple regression analysis revealed the effect of process parameters on tablet properties and drug release with increasing the granulation time affording sustained release of the drug. The analysis also showed that a high compression force crushed the granules coated by TR-FB, which impaired sustained drug release. From the regression model the optimal manufacturing conditions were determined, and the tablet prepared under these conditions concurred with the predicted values and met all criteria. This new technique should contribute to the development of ODT to improve medication adherence.


Assuntos
Compostos de Alumínio/química , Compostos de Magnésio/química , Silicatos/química , Administração Oral , Adsorção , Ésteres/química , Ácidos Graxos/química , Glicerol/química , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , Propriedades de Superfície , Comprimidos/administração & dosagem , Comprimidos/química
17.
Org Biomol Chem ; 17(37): 8628-8635, 2019 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-31528943

RESUMO

Nucleophilic ring opening of cyclohexene oxides is known to proceed preferentially through the trans-diaxial pathway (the Fürst-Plattner rule). This preference, however, is not absolute, and can be affected by substituents on the cyclohexene oxide ring, as illustrated by LiAlH4 ring-opening of the cis- and trans-isomers of 4-t-butyl- and 3-methylcyclohexene oxide (cis- and trans-1, cis- and trans-2). We performed B3LYP/6-31+G*(PCM) geometry optimizations to locate the chair-like and twist-boat-like transition structures for the hydride attacks on the pseudoaxial and pseudoequatorial conformers of these epoxides. Our calculations are consistent with the experimental observation of effective Fürst-Plattner control of AlH4--opening of cis-1, trans-1, and cis-2, but low selectivity in ring-opening of trans-2. Our data at B3LYP/6-31+G*(PCM) suggests this reduction in selectivity is due to a diminished pseudoequatorial preference of the 3-methyl group in trans-2 relative to that in cis-2. The two calculated chair-like transition structures for hydride opening of trans-2 differ in activation energy free energy (ΔΔG‡) by only 0.4 kcal mol-1. Thus, these calculations account for the reduced regioselectivity of ring opening seen for trans-2 by AlH4- and other nucleophiles.


Assuntos
Compostos de Alumínio/química , Cicloexenos/química , Teoria da Densidade Funcional , Compostos de Lítio/química , Óxidos/química , Conformação Molecular , Estereoisomerismo
18.
Braz Oral Res ; 33: e042, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31508725

RESUMO

This study evaluated the cytotoxicity and biocompatibility of a new bioceramic endodontic sealer (i.e., Sealer Plus BC) in comparison with those of MTA Fillapex and AH Plus. L929 fibroblasts were cultured and Alamar Blue was used to evaluate cell viability of diluted extracts (1:50, 1:100, and 1:200) from each sealer at 24 h. Polyethylene tubes that were filled with material or empty (as a control) were implanted in the subcutaneous tissue of rats. The rats were killed after 7 and 30 d (n = 8), and the tubes were removed for histological analysis. Parametric data was analyzed using a one-way ANOVA test, and nonparametric data was analyzed via the Kruskal-Wallis test followed by the Dunn test (p < 0.05). A reduction in cell viability was observed in the extracts that were more diluted for Sealer Plus BC when compared to that of Control and AH Plus (p < 0.05). However, the 1:50 dilution of the Sealer Plus BC was similar to that of the Control (p > 0.05). Conversely, more diluted extracts of MTA Fillapex (1:200) and AH Plus (1:100 and 1:200) were similar to the Control (p > 0.05). Histological analysis performed at 7 d did not indicate any significant difference between tissue response for all materials, and the fibrous capsule was thick (p > 0.05). At 30 d, Sealer Plus BC was similar to the Control (p > 0.05) and MTA Fillapex and AH Plus exhibited greater inflammation than the Control (p < 0.05). The fibrous capsule was thin for the Control and for most specimens of Sealer Plus BC and AH Plus. Thus, Sealer Plus BC is biocompatible when compared to MTA Fillapex and AH Plus, and it is less cytotoxic when less-diluted extracts are used.


Assuntos
Cimentos para Ossos/química , Hidróxido de Cálcio/química , Cerâmica/química , Materiais Restauradores do Canal Radicular/química , Compostos de Alumínio/química , Animais , Materiais Biocompatíveis , Cimentos para Ossos/farmacologia , Cimentos para Ossos/toxicidade , Compostos de Cálcio/química , Hidróxido de Cálcio/farmacologia , Hidróxido de Cálcio/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas/efeitos dos fármacos , Combinação de Medicamentos , Resinas Epóxi/química , Fibroblastos/efeitos dos fármacos , Técnicas In Vitro , Inflamação , Masculino , Teste de Materiais , Óxidos/química , Ratos Wistar , Materiais Restauradores do Canal Radicular/toxicidade , Silicatos/química , Tela Subcutânea/patologia
19.
J Appl Oral Sci ; 27: e20180556, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31508791

RESUMO

OBJECTIVE: To evaluate the effect of ultrasonic and sonic activation on physicochemical properties of AH Plus, MTA Fillapex, ADSeal, GuttaFlow Bioseal, and GuttaFlow 2 sealers. METHODOLOGY: Three experimental groups were formed: no activation (NA), ultrasonic activation (UA), and sonic activation (SA). The sealers were manipulated according to the manufacturers' instructions. A 3-mL syringe was adapted to receive 1 mL of sealer. Activation was performed with a 20/.01 ultrasonic insert (20 s/1W) in the UA group. A size 35.04 sonic tip was used (20 s/10,000 cycles/min-1) in the SA group. The molds for physicochemical analysis were filled and evaluated according to ANSI/ADA specification no. 57: setting time (ST), flow (FL), dimensional change (DC), solubility (SB), and radiopacity (RD). Statistical analysis was performed by Kruskal-Wallis, one-way ANOVA, and Tukey's tests (P<0.05). RESULTS: Regarding ST, only AH Plus and GuttaFlow 2 in the NA group met the ANSI/ADA standards. All FL values were greater than 20 mm in diameter, as determined by ANSI/ADA. The tested sealers and protocols did not comply with the ANSI/ADA standards for DC. As for SB, only MTA Fillapex, regardless of the activation protocol, did not follow the ANSI/ADA standards. All of the investigated sealers, regardless of the activation protocol, presented radiographic density higher than 3 mm Al, as proposed by ANSI/ADA. CONCLUSIONS: UA and SA promoted changes in the physicochemical properties of the evaluated root canal sealers, mainly in ST and F. Thus, it is important to evaluate the physicochemical properties of endodontic sealers associated with activation techniques prior to clinical application in order to determine whether the properties follow the parameters set by ANSI/ADA, ensuring safety and quality of root canal filling.


Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Dimetilpolisiloxanos/química , Resinas Epóxi/química , Guta-Percha/química , Óxidos/química , Materiais Restauradores do Canal Radicular/química , Silicatos/química , Ondas Ultrassônicas , Análise de Variância , Combinação de Medicamentos , Teste de Materiais , Valores de Referência , Reprodutibilidade dos Testes , Solubilidade , Estatísticas não Paramétricas , Propriedades de Superfície , Fatores de Tempo
20.
Scanning ; 2019: 3484396, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31531154

RESUMO

Introduction: Elastin-like polypeptide (ELP) supplementation was previously reported to enhance the physical properties of mineral trioxide aggregate (MTA). The aim of this study was to investigate the effect of ELP supplementation on the bonding properties of MTA to dentin. Methods: Two types of ELPs were synthesized and mixed with MTA in a 0.3 liquid/powder ratio. The push-out bond strength test and interfacial observation with scanning electron microscopy were performed for ELP-supplemented MTA. The porosity of MTA fillings in the cavity was observed with microcomputed tomography. The stickiness, flow rate, and contact angle were additionally measured for potential increased bonding properties. Results: ELP supplementation improved the bond strength of MTA to dentin. MTA supplemented by a specific ELP exhibited a less porous structure, higher stickiness, and higher flow rate. ELPs also decreased the contact angle to dentin. Conclusions: This research data verifies that ELP improves the bonding properties of MTA to a tooth structure. The sticky and highly flowable characteristics of ELP-supplemented MTA may provide intimate contact with dentin and supply a less porous cement structure, which might improve the bonding properties of MTA.


Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Colagem Dentária/métodos , Materiais Dentários/química , Elastina/química , Óxidos/química , Peptídeos/química , Silicatos/química , Combinação de Medicamentos , Humanos , Microscopia Eletrônica de Varredura , Microtomografia por Raio-X
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