Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 47
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Dent Mater ; 40(1): 102-110, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37919112

RESUMO

OBJECTIVES: This study aimed to enhance the bond strength between Biodentine™ (BD), a bioactive tricalcium silicate (C3S) based material, and resin composite through various surface treatments. METHODOLOGY: BD samples were immersed in either double distilled water or Hank's Balanced Salt Solution and analyzed using X-ray Diffraction (XRD). Shear bond strength (SBS) evaluations of BD were performed using Prime & Bond™ NT (PNT), Single Bond Universal (SBU), Xeno V (Xeno), and glass ionomer cement (GIC) following various etching durations (0 s/ 15 s/ 30 s/ 60 s with 37.5% phosphoric acid). Two primers, RelyX™ Ceramic Primer (RCP) and Monobond ™ Plus (MBP), were chosen to prime BD for SBS enhancement. Fractography and bonding interfaces were examined with energy dispersive X-ray spectroscopy (EDS)/ scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). RESULTS: XRD confirmed BD's main compositions as C3S, Ca(OH)2, CaCO3 and ZrO2 after 14 days crystal maturation. Etched BD did not improve SBS. GIC exhibited the lowest SBS (p < 0.05) among all adhesives, regardless of the etching mode (all < 1 MPa). The highest SBS (17.5 ± 3.6 MPa, p < 0.05) was achieved when BD primed with MBP followed by SBU application. FTIR and EDS showed γ-MPTS and10-MDP within the MBP primer interacted with C3S and ZrO2 of BD, achieving enhanced SBS. Most specimens exhibited mixed or cohesive failure modes. Significance BD's subpar mechanical properties and texture may contribute to its poor adhesion to resin composite. Pretreating BD with MBP primer, followed by SBU adhesive is recommended for improving bond strength.


Assuntos
Colagem Dentária , Cimentos de Resina , Cimentos de Resina/química , Propriedades de Superfície , Materiais Dentários/química , Resinas Compostas/química , Cimentos de Ionômeros de Vidro , Resistência ao Cisalhamento , Teste de Materiais
2.
ACS Omega ; 8(46): 44229-44237, 2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-38027393

RESUMO

A mesoporous Eu3+-doped zinc/silicate phosphor with a large surface area (>100 m2g-1) and amorphous structure was prepared in an aqueous solution without using any organic template. The residual concentration of the Zn2+ ion in the filtrate is lower than the standard of effluent 3.5 ppm under a pH 8-11 preparation condition. When a sulfide ion (S2-) is present in aqueous solution, the phosphor can react with the sulfide ion to transform from the amorphous structure to the crystalline ZnS, which causes structural transformation and a subsequent decrease in luminescent intensity. This distinct phosphor with a high surface area and amorphous structure can be applied through the structure transformation mechanism for highly selective and sensitive detection of the sulfide ions at low concentrations. In addition, the luminescent efficiency was obtained from adjustments in the pH value, calcination temperature, and Eu3+ ion concentration. The quenching efficiency, the limit of detection (CLOD), S2- ion selectivity, and phosphor regeneration ability were systematically explored in sulfide ion detection tests. Due to the novel S2- ion-induced structural transformation, we found that the amorphous Eu3+-doped zinc/silicate phosphors demonstrate a CLOD sensitivity as low as 1.8 × 10-7 M and a high Stern-Volmer constant (KSV) of 3.1 × 104 M-1. Furthermore, the phosphors were easily regenerated through simple calcination at 500 °C and showed a KSV value of 1.4 × 104 M-1. Overall, the Eu3+-doped zinc/silicates showed many advantageous properties for detecting sulfide ions, including low toxicity, green synthesis, good selectivity, high sensitivity, and good renewability.

3.
Membranes (Basel) ; 12(10)2022 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-36295721

RESUMO

A benzimidazole-containing diamine monomer was prepared via a simple one-step synthesis process. A two-step procedure involving polycondensation in the presence of aromatic dianhydrides (4,4'-oxydiphthalic anhydride, ODPA) followed by thermal imidization was then performed to prepare a benzimidazole-based polyimide (BI-PI). BI-PI membranes were fabricated using an electrospinning technique and were hot pressed for 30 min at 200 °C under a pressure of 50 kgf /cm2. Finally, the hot-pressed membranes were assembled into supercapacitors, utilizing high-porosity-activated water chestnut shell biochar as the active material. The TGA results showed that the BI-PI polymer produced in the two-step synthesis process had a high thermal stability (Td5% = 527 °C). Moreover, the hot-press process reduced the pore size in the BI-PI membrane and improved the pore-size uniformity. The hot-press procedure additionally improved the mechanical properties of the BI-PI membrane, resulting in a high tensile modulus of 783 MPa and a tensile strength of 34.8 MPa. The cyclic voltammetry test results showed that the membrane had a specific capacitance of 121 F/g and a capacitance retention of 77%. By contrast, a commercial cellulose separator showed a specific capacitance value of 107 F/g and a capacitance retention of 49% under the same scanning conditions. Finally, the membrane showed both a small equivalent series resistance (Rs) and a small interfacial resistance (Rct). Overall, the results showed that the BI-PI membrane has significant potential as a separator for high-performance supercapacitor applications.

4.
J Hazard Mater ; 439: 129567, 2022 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-36104894

RESUMO

The separation of oily wastewater, specifically emulsions, is a crucial global issue. Possible strategies for the efficient separation of emulsified oil/water mixtures through sustainable and environmentally friendly materials have recently drawn considerable attention. In our study, we prepared superwetting water caltrop shell biochar (WCSB) via a top-lit-updraft carbonization procedure. The as-prepared WCSB was characterized by superhydrophilicity, underwater superoleophobicity, underoil superhydrophilicity, and underoil water adsorption ability. Because of its superwetting properties, WCSB was used for the separation of both surfactant-stabilized oil-in-water emulsions (SOIWEs) and surfactant-stabilized water-in-oil emulsions (SWIOEs) with very high fluxes (up to 74,700 and 241,000 L m-2 h-1 bar-1 for SOIWE and SWIOE, respectively). The separation performances were excellent, with oil contents in all SOIWE filtrates lower than 10 ppm and oil purities in all SWIOE filtrates higher than 99.99 wt%. Moreover, WCSB was applied to separate dye-spiked emulsions. Due to their high emulsion separation ability, sustainability, good biocompatibility, and ease of mass production, the as-prepared WCSBs have notable potential for utilitarian applications.


Assuntos
Óleos , Águas Residuárias , Carvão Vegetal , Emulsões , Tensoativos
5.
Langmuir ; 38(19): 6217-6223, 2022 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-35512026

RESUMO

In recent years, the application of low-refractive-index materials in the optical field has attracted considerable attention due to it high transmittance and high optical sensitivity. In this study, we synthesized SiO2 porous hollow spheres (SPHS) with an ultralow refractive index (n = 1.05) by using a templating method. Their refractive indices could be easily controlled from 1.05 to 1.08 by tuning the thickness of shell. In addition, a droplet coatings method is proposed for SPHS colloidal crystal (CC) by controlling the temperature and humidity. The SPHS CCs displayed distinct structural colors when the incident angle was adjusted and demonstrated high angular resolution. Moreover, the iridescent color changes could be observed with the naked eye. For surface-enhanced Raman scattering application, more analyte could be absorbed by the porous shells, and metal nanoparticles were coated on the SPHSs surface to increase the hot spot density for improving the SERS intensity.

6.
ACS Omega ; 7(51): 47610-47618, 2022 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-36591207

RESUMO

In this work, a solvent-free ZnO-template method is used to synthesize hierarchical porous carbons (denoted as HPC-X; X = 1, 1.5, 2, and 4 g of ZnO) via the pyrolysis of petroleum industrial-residual pitch with ZnO. The proposed method allows precise control of the micro/meso/macroporous structure of the HPC by adjusting the amount of ZnO. The results show that the average pore size of HPCs prominently increases from 2.4 to 3.7 nm with the increase in the ZnO/pitch ratio. In addition, it is shown that HPCs have a high surface area between 1141 and 1469 m2 g-1, a wide-range pore size distribution (micro-, meso-, and macropores), and a tap density ranging from 0.2 to 0.57 g cm-3. The capacitive deionization performances of HPCs for sodium and chloride ions are investigated. The results show that HPC-2 exhibits the highest electrosorption capacity of 9.94 mg g-1 within 10.0 min and a maximum electrosorption capacity of 10.62 mg g-1 at 1.2 V in a 5.0 mM NaCl solution. Hence, HPC-2 is a highly promising candidate as an electrode material for rapid deionization.

7.
Int J Mol Sci ; 23(1)2021 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-35008462

RESUMO

Multiporous carbons (MPCs) are prepared using ZnO as a hard template and biomass pyrolysis oil as the carbon source. It is shown that the surface area, pore volume, and mesopore/micropore ratio of the as-prepared MPCs can be easily controlled by adjusting the ZnO/oil ratio. Sulfur/MPC (S/MPC) composite is prepared by blending sulfur powder with the as-prepared MPCs followed by microwave heating at three different powers (100 W/200 W/300 W) for 60 s. The unique micro/mesostructure characteristics of the resulting porous carbons not only endow the S/MPC composite with sufficient available space for sulfur storage, but also provide favorable and efficient channels for Li-ions/electrons transportation. When applied as the electrode material in a lithium-ion battery (LIB), the S/MPC composite shows a reversible capacity (about 500 mAh g-1) and a high columbic efficiency (>95%) after 70 cycles. Overall, the method proposed in this study provides a simple and green approach for the rapid production of MPCs and S/MPC composite for high-performance LIBs.


Assuntos
Carbono/química , Lítio/química , Enxofre/química , Biomassa , Fontes de Energia Elétrica , Eletrodos , Química Verde/métodos , Micro-Ondas , Óleos/química , Pós/química
8.
RSC Adv ; 11(26): 15738-15747, 2021 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-35481169

RESUMO

A green synthesis method is proposed for the preparation of nitrogen-doped multiporous carbons (denoted as N-MPCs) from water-caltrop shell (WCS) using eggshell waste as both a nitrogen-dopant and an activating agent. It is shown that the surface area, porosity, yield and nitrogen content of the as-prepared N-MPCs can be easily controlled by adjusting the activation temperature. Moreover, in oxygen reduction reaction (ORR) tests performed in O2-saturated 0.1 M KOH(aq) electrolyte containing 1.0 M methanol, the N-MPC catalysts show a high ORR stability and good resistance to methanol corrosion. In addition, as a cathode material in Al-air battery tests, the N-MPCs achieve a power density of 16 mW g-1 in a saturated NaCl(aq) electrolyte. Overall, the results show that the N-MPCs have a promising potential as a green and sustainable material for ORR catalysis applications.

10.
RSC Adv ; 11(17): 10010-10017, 2021 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-35423525

RESUMO

An investigation is performed into the efficiency of the Streptomyces griseus HUT 6037 enzyme immobilized in three different mesoporous silicas, namely mesoporous silica film, mesocellular foam, and rod-like SBA-15. It is shown that for all three supports, the pH value changes the surface charge and charge density and hence determines the maximum loading capacity of the enzyme. The products of the enzyme hydrolytic reaction are analyzed by 1H-NMR. The results show that among the three silica supports, the mesoporous silica film (with a channel length in the range of 60-100 nm) maximizes the accessibility of the immobilized enzyme. The loading capacity of the enzyme is up to 95% at pH 7 and the activity of the immobilized enzyme is maintained for more than 15 days when using a silica film support. The order of the activity of the enzyme immobilized in different mesoporous silica supports is: mesoporous silica film > mesocellular foam > rod-like SBA-15. Furthermore, the immobilized enzyme can be easily separated from the reaction solution via simple filtration or centrifugation methods and re-used for hydrolytic reaction as required.

11.
Arch Microbiol ; 203(2): 621-627, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32997153

RESUMO

A novel moderately halophilic bacterial strain, designated YIM 93176T, was isolated from a saltern in Korea and subjected to a polyphasic taxonomic study. This isolate YIM 93176T was observed to grow in the presence of 0-22% (w/v) NaCl and at pH 6.0-10.0 and 10-45 °C; optimum growth was observed with 5-10% (w/v) NaCl and at pH 7.0-9.0 and 28-37 °C. Based on 16S rRNA gene sequences analysis, the nearest relatives were Lentibacillus alimentarius M2024T (96.5% similarity), followed by Virgibacillus carmonensis LMG 20964T (96.0%) and the other type strains of the family Bacillaceae, but phylogenetic analysis indicated that strain YIM 93176T belonged to the cluster comprising type species of the genus Lentibacillus. Genome sequencing of strain YIM 93176T revealed a genome size of 3.2 Mb and a DNA G + C content of 40.5 mol%. The major fatty acids were anteiso-C15:0 (40.7%) and iso-C15:0 (26.4%), while the predominant respiratory quinone was menaquinone 7. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. These genotypic and chemotaxonomic characteristics supported affiliation of strain YIM 93176T to the genus Lentibacillus. In addition, phenotypic characteristics could distinguish strain YIM 93176T from its closely related species in genus Lentibacillus. Based on the cumulative evidences from the polyphasic taxonomic study, strain YIM 93176T represents a novel species of the genus Lentibacillus, for which name Lentibacillus saliphilus sp. nov. (type strain YIM 93176T = CCTCC AB 208139T = DSM 21375T) is proposed.


Assuntos
Bacillaceae/classificação , Bacillaceae/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Bacillaceae/genética , Bacillaceae/isolamento & purificação , Composição de Bases , Ácidos Graxos/análise , Genoma Bacteriano/genética , Filogenia , RNA Ribossômico 16S/genética , República da Coreia , Especificidade da Espécie
12.
ACS Omega ; 5(18): 10626-10632, 2020 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-32426621

RESUMO

In this study, an economic, sustainable, and green synthesis method of multiporous carbons from agricultural waste, water caltrop shell (denoted as WCS), was presented. To prepare the WCS biochar, the dried WCS was first carbonized to a microporous carbon with a surface area of around 230 m2 g-1 by using a top-lit-updraft method. Then, the microporous WCS biochar was directly mixed with an appropriate amount of ZnO nanoparticles and KOH as activating agents via a solvent-free physical blending route. After further activation at 900 °C, the resulted carbons possess both micropores and mesopores that were named as WCS multiporous carbons. The carbon yield of the prepared WCS multiporous carbons with high surface area in the range of 1175-1537 m2 g-1 is up to 50%. Furthermore, the micropore/mesopore surface area ratio can be simply tuned by controlling the ZnO content. For supercapacitor applications, the as-prepared WCS multiporous carbon electrodes showed high specific capacitance (128 F g-1 at 5 mV s-1) with a good retention rate at 500 mV s-1 scan rate (>60% compared to the capacitance at 5 mV s-1) and low Ohmic resistance in a 1.0 M LiClO4/PC electrolyte. In addition to the ZnO nanoparticles, CaCO3 nanoparticles with low environmental impact were also used to prepare the WCS multiporous carbons. The assembled supercapacitors also demonstrate high specific capacitance (102 F g-1 at 5 mV s-1) and good retention rate (∼70%).

13.
J Formos Med Assoc ; 119(12): 1835-1841, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32192793

RESUMO

BACKGROUND/PURPOSE: One effective way to deal with dentin hypersensitivity is to develop materials to seal the tubules. The porous bio-calcium carbonate-silica (BCCS) contained well-dispersed CaCO3 would form calcium phosphates to seal the dentinal tubules when mixed with an acidic solution. The acidic hydrothermal treatment and calcination to isolate the BCCS from the agricultural waste like equisetum grass was used, which would be more environmentally friendly than chemically synthesized mesoporous biomaterials. The aim of this study was to develop mesoporous materials from natural resources to occlude the dentinal tubules which could be more environmentally-friendly. METHODS: Dentin disc samples were prepared and treated with different methods as follows: (1) BCCS mixed with H3PO4; (2) BCCS mixed with KH2PO4; (3) Seal & Protect® was used as a comparison group. Sealing efficacy was evaluated by measuring the depths and percentages of precipitate occlusion in dentinal tubules with SEM. RESULTS: The N2 adsorption-desorption isotherm of the BCCS demonstrated a pore size of around 15.0 nm and a surface area of 61 m2g-1. From the results of occlusion percentage and depth, the BCCS treated with H3PO4 or KH2PO4 demonstrated promising sealing efficacy than the commercial product. CONCLUSION: This synthetic process used the agricultural waste equisetum grass to produce bio-calcium carbonate-silica would be environmentally friendly, which has great potential in treating exposed dentin related diseases.


Assuntos
Equisetum , Carbonato de Cálcio , Cristalização , Dentina , Sensibilidade da Dentina , Humanos , Microscopia Eletrônica de Varredura , Poaceae , Dióxido de Silício
14.
Chemosphere ; 250: 126219, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32105856

RESUMO

Ionic liquids (ILs (1-butyl-3-methylimidazolium chloride ([C4mim][Cl]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]))) were used as heat transfer fluids for solar thermal collectors. The additive of ILs was biochar containing copper and silver nanoparticles (Cu-Ag/biochar) to improve the adsorption of solar irradiation and thermal conductivities. After impregnation and reduction processes, nanoparticles such as Cu, CuO, Cu(OH)2, Ag, and Ag2O were found in the biochar by X-ray powder diffraction (XRD) spectroscopy. With adding 2% Cu-Ag/biochar into the ILs, the thermal conductivities of [C4mim][Cl] and [C4mim][BF4] containing 10% Cu-1% Ag/biochar were individually increased 9.2 and 6.6 times compared to the base ILs due to the high graphitization of biochar and metallic nanoparticles. The 1H NMR (nuclear magnetic resonance) features of the imidazole ring and methyl group in the ILs were highly disturbed due to the formation of weak or strong hydrogen bonds between the cations in ILs and Cu-Ag/biochar. The high hydrogen bond acceptance of anions in ILs also affected the thermal properties. The thermal properties of the metals/biochar [C4mim][Cl] were better than those of metals/biochar [C4mim][BF4] due to high hydrogen bond acceptance of [Cl]-. The strong hydrogen bonds between the Cu-Ag/biochar and the cations and anions in ILs result in thermal properties of heat transfer fluids. Under simulated sunlight, the temperatures of [C4mim][Cl] and [C4mim][BF4] containing 10% Cu-1% Ag/biochar rose from 304 to 345 and 340 K within 24 min, respectively. A novel heat transfer fluid was developed for high adsorption of irradiation, high thermal conductivities, and speedy transfer of heat.


Assuntos
Nanopartículas Metálicas/química , Modelos Químicos , Adsorção , Ânions/química , Cátions , Carvão Vegetal , Ligação de Hidrogênio , Imidazóis/química , Líquidos Iônicos/química , Prata
15.
Materials (Basel) ; 12(20)2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31614495

RESUMO

Three-dimensional (3D) cell culture models have become powerful tools because they better simulate the in vivo pathophysiological microenvironment than traditional two-dimensional (2D) monolayer cultures. Tumor cells cultured in a 3D system as multicellular cancer aggregates (MCAs) recapitulate several critical in vivo characteristics that enable the study of biological functions and drug discovery. The microwell, in particular, has emerged as a revolutionary technology in the generation of MCAs as it provides geometrically defined microstructures for culturing size-controlled MCAs amenable for various downstream functional assays. This paper presents a simple and economical microwell fabrication methodology that can be conveniently incorporated into a conventional laboratory setting and used for the discovery of therapeutic interventions for liver cancer. The microwells were 400-700 µm in diameter, and hepatic MCAs (Huh-7 cells) were cultured in them for up to 5 days, over which time they grew to 250-520 µm with good viability and shape. The integrability of the microwell fabrication with a high-throughput workflow was demonstrated using a standard 96-well plate for proof-of-concept drug screening. The IC50 of doxorubicin was determined to be 9.3 µM under 2D conditions and 42.8 µM under 3D conditions. The application of photothermal treatment was demonstrated by optimizing concanavalin A-FITC conjugated silica-carbon hollow spheres (SCHSs) at a concentration of 500:200 µg/mL after a 2 h incubation to best bind with MCAs. Based on this concentration, which was appropriate for further photothermal treatment, the relative cell viability was assessed through exposure to a 3 W/cm2 near-infrared laser for 20 min. The relative fluorescence intensity showed an eight-fold reduction in cell viability, confirming the feasibility of using photothermal treatment as a potential therapeutic intervention. The proposed microwell integration is envisioned to serve as a simple in-house technique for the generation of MCAs useful for discovering therapeutic modalities for liver cancer treatment.

16.
J Chem Phys ; 150(16): 164703, 2019 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-31042892

RESUMO

X-ray photoelectron spectroscopy, reflection-absorption infrared spectroscopy, and temperature-programmed reaction/desorption have been employed to investigate the adsorption and reaction pathways of CH2=CHCOOH and CH3CHFCOOH on Cu(100) and oxygen-precovered Cu(100) [O/Cu(100)]. In the case of CH2=CHCOOH on O/Cu(100), CH2=CHCOO is the surface intermediate detected between 110 K and 400 K. CH2=CHCOO is adsorbed vertically and can change adsorption sites at a higher temperature. The propenoate (acrylate) decomposes at higher temperatures (>500 K), with formation of >C=C=O (ketenylidene) surface species and gaseous products. On Cu(100), CH2=CHCOOH is adsorbed in dimer form and can dissociate to generate CH2=CHCOO and CH3CHCOO intermediates on the surface. The CH3CHCOO continuously recombines with the H from deprotonation of CH2=CHCOOH, resulting in the formation CH3CH2COO. The co-existing CH2=CHCOO and CH3CH2COO further decompose at ∼550 K to evolve reaction products, but without >C=C=O being detected. On O/Cu(100), CH3CHFCOOH readily deprotonates to form CH3CHFCOO at 120 K. This intermediate reacts on the surface at ∼460 K to evolve gaseous products, also producing CH2=CHCOO. In the case of Cu(100), deprotonation of CH3CHFCOOH occurs at ∼250 K, forming CH3CHFCOO. Without oxygen on the surface, this intermediate decomposes into HF and CH2=CHCOO at ∼455 K.

17.
J Dent ; 83: 61-66, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30825570

RESUMO

OBJECTIVES: The aim of this study was to investigate the novel mesocellular siliceous foams (MCF) containing CaCO3 nanoparticles (denoted as CMCF) combined with phosphoric acid could occlude dentinal tubules through the formation of biomimetic crystal barrier. METHODS: Ultrastructures of MCF and CMCF were examined by transmission electron microscopy (TEM). Elemental components were analyzed with energy dispersive X-ray spectrometry (EDX). CMCF was mixed with distilled water, 10%, 20% and 30% phosphoric acid then applied on dentine discs. Crystals were characterized by X-ray powder diffractometry (XRD). The sealing efficacy of the dentinal tubules was examined by scanning electron microscopy. RESULTS: TEM images showed MCF presented a pore size of approximately 30.0 nm and CMCF contained abundant nano-CaCO3. Sealing efficacy showed that CMCF, when reacted with 30% phosphoric acid, would form crystals in the dentinal tubules to a depth of 83.2 ± 17.6 µm at an occlusion percentage of 75.6 ± 12.8% on average; both occlusion percentage and depth were higher than those obtained with 10% or 20% phosphoric acid (p < 0.05). The results of XRD and EDS indicated that the crystal growth in the dentinal tubules could be transformed into the biomimetic crystals. CONCLUSION: This study showed that the CMCF with 30% phosphoric acid could effectively occlude the dentinal tubules through the formation of biomimetic crystal barrier. CLINICAL SIGNIFICANCE: The novel CMCF combined with phosphoric acid may have potential for the treatment of dentine hypersensitivity.


Assuntos
Cálcio , Sensibilidade da Dentina , Dentina/química , Cristalização , Humanos , Microscopia Eletrônica de Varredura
18.
ACS Appl Mater Interfaces ; 10(39): 33307-33315, 2018 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-30198255

RESUMO

This study applies a low-cost solvothermal method to synthesize all-inorganic (lead-free cesium tin halide) perovskite quantum dots (AIPQDs) and to fabricate AIPQD-doped lasers with cholesteric liquid crystal (CLC) lasing cavities. The lasers present highly qualified lasing features of low threshold (150 nJ/pulse) and narrow line width (0.20 nm) that are attributed to the conjunction of the suppression of photoluminescence (PL) loss caused by the quantum confinement of AIPQDs and the amplification of PL caused by the band-edge effect of the CLC-distributed feedback resonator. In addition, the lasers possess highly flexible lasing-wavelength tuning features and a long-term stability under storage at room temperature and under high humidity given the protective role of CLC. These advantages are difficult to confer to typical light-emitting perovskite devices. Given these merits, the AIPQD-doped CLC laser device has considerable potential applications in optoelectronic and photonic devices, including lighting, displays, and lasers.

19.
Int J Nanomedicine ; 13: 261-271, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29386894

RESUMO

Mineral trioxide aggregate (MTA) is the most frequently used repair material in endodontics, but the long setting time and reduced mechanical strength in acidic environments are major shortcomings. In this study, a novel sol-gel-derived calcium silicate cement (sCSC) was developed using an initial Ca/Si molar ratio of 3, with the most effective mixing orders of reactants and optimal HNO3 catalyst volumes. A Fourier transform infrared spectrometer, scanning electron microscope with energy-dispersive X-ray spectroscopy, and X-ray powder diffractometer were used for material characterization. The setting time, compressive strength, and microhardness of sCSC after hydration in neutral and pH 5 environments were compared with that of MTA. Results showed that sCSC demonstrated porous microstructures with a setting time of ~30 min, and the major components of sCSC were tricalcium silicate, dicalcium silicate, and calcium oxide. The optimal formula of sCSC was sn200, which exhibited significantly higher compressive strength and microhardness than MTA, irrespective of neutral or pH 5 environments. In addition, both sn200 and MTA demonstrated good biocompatibility because cell viability was similar to that of the control. These findings suggest that sn200 merits further clinical study for potential application in endodontic repair of perforations.


Assuntos
Endodontia/métodos , Géis/química , Cimento de Silicato/química , Animais , Cálcio/química , Compostos de Cálcio/química , Força Compressiva , Polpa Dentária/citologia , Polpa Dentária/efeitos dos fármacos , Endodontia/instrumentação , Concentração de Íons de Hidrogênio , Teste de Materiais , Óxidos/química , Porosidade , Difração de Pó , Ratos , Cimento de Silicato/efeitos adversos , Silicatos/química , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Fatores de Tempo , Difração de Raios X
20.
RSC Adv ; 8(64): 36775-36784, 2018 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-35558959

RESUMO

Chemo-photothermal therapy, which exhibits synergistic effects, is more effective than either of the treatments administered alone because of its superior ability to target and destroy cancer cells. An anti-cancer compound (doxorubicin, DOX) was embedded in silica-carbon hollow spheres (SCHSs) using heat and vacuum to integrate multi-therapeutic effects onto one platform and subsequently improve the anti-cancer efficacy. SCHSs were synthesized via a surface activation method and its highly porous surface enhanced the loading content of the desired drug. SCHSs are an infrared photothermal material that can destroy targeted cells by heating under near-infrared (NIR) laser illumination at 808 nm. NIR laser illumination also enhances DOX release from SCHSs to increase the anti-cancer efficiency of DOX-loaded SCHSs (DOX-SCHSs) in both two-dimensional and three-dimensional multicellular tumor spheroid cultures. SCHSs exhibited high heat-generating ability and pH-responsive drug delivery. In conclusion, this study demonstrated that DOX-SCHSs represent a potential tool for chemo-photothermal therapy due to its photothermal effects. Thus, our findings imply that the high cancer cell killing efficiency of DOX-SCHSs induced by NIR illumination can be used for the treatment of tumors.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...