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1.
Chemosphere ; 254: 126873, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957285

RESUMO

The removal of organic pollutants from water is highly desired because of the development of industrial and social economy. Superhydrophilic and underwater superoleophobic membranes are emerging materials for effective oil/water separation. In this paper, superhydrophilic and underwater superoleophobic polypropylene (PP) melt-blown membranes were prepared through melt-blown and in situ growth method, achieving highly efficient oil/water separation. After in situ growth, polydopamine (PDA) grows on the surface of PP fibers, and the addition of coupling agent (3-aminopropyltriethoxysilane, APTES) can improve the stability of the membrane in harsh environments (1 M HCl, 1 M NaOH, 1 M NaCl). The PDA/APTES@PP membrane could dramatically enhance the wetting (water contact angle ∼0, underwater oil contact angle∼154°) compare with the pristine PP melt-blown membrane (water contact angle ∼130°, underwater oil contact angle ∼0). Moreover, the filtration performance is at a high level (∼99%). The behaviors are comparable or even superior to the typical reported results in the references (such as the mussel-inspired superhydrophilic PVDF membrane and copper mesh). This method provides a facile route to prepared multi-functional membrane for highly efficiency oil/water separation and industrial oily wastewater remediation.


Assuntos
Indóis/análise , Polímeros/análise , Cobre , Interações Hidrofóbicas e Hidrofílicas , Membranas Artificiais , Óleos , Águas Residuárias , Água , Purificação da Água , Molhabilidade
2.
Adv Exp Med Biol ; 1267: 101-115, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32894479

RESUMO

Pathogenic bacteria colonize or disseminate into cells and tissues by inducing large-scale remodeling of host membranes. The physical phenomena underpinning these massive membrane extension and deformation are poorly understood. Invasive strategies of pathogens have been recently enriched by the description of a spectacular mode of opening of large transendothelial cell macroaperture (TEM) tunnels correlated to the dissemination of EDIN-producing strains of Staphylococcus aureus via a hematogenous route or to the induction of gelatinous edema triggered by the edema toxin from Bacillus anthracis. Remarkably, these highly dynamic tunnels close rapidly after they reach a maximal size. Opening and closure of TEMs in cells lasts for hours without inducing endothelial cell death. Multidisciplinary studies have started to provide a broader perspective of both the molecular determinants controlling cytoskeleton organization at newly curved membranes generated by the opening of TEMs and the physical processes controlling the dynamics of these tunnels. Here we discuss the analogy between the opening of TEM tunnels and the physical principles of dewetting, stemming from a parallel between membrane tension and surface tension. This analogy provides a broad framework to investigate biophysical constraints in cell membrane dynamics and their diversion by certain invasive microbial agents.


Assuntos
Bactérias/patogenicidade , Membrana Celular/microbiologia , Membrana Celular/patologia , Células Endoteliais/microbiologia , Células Endoteliais/patologia , Molhabilidade , Membrana Celular/metabolismo , Edema/metabolismo , Edema/microbiologia , Edema/patologia , Células Endoteliais/metabolismo , Humanos , Tensão Superficial
3.
Int J Nanomedicine ; 15: 5813-5824, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32821103

RESUMO

Introduction: This paper presents a novel technique for the synthesis of graphene oxide (GO) with various surface features using high-density atmospheric plasma deposition. Furthermore, to investigate the use of hydrophobic, super-hydrophobic, and hydrophilic graphene in biological applications, we synthesized hydrophobic, super-hydrophobic, and hydrophilic graphene oxides by additional heat treatment and argon plasma treatment, respectively. In contrast to conventional fabrication procedures, reduced graphene oxide (rGO) formed under low pressure and high-temperature environment using a new synthesis method-developed and described in this study-offers a convenient deposition method on any kind surface with controlled wettability. Methods: High density at atmospheric plasma is used for the synthesis of rGO and GO and its biocompatibility based on various wetting properties was evaluated using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, and the viability of cells in response to rGO and GO with various surface features was investigated. Structural integrity was characterized by Raman spectroscopy, FESEM and FE-TEM. Wettability was measured via contact angle method and confirmed with XPS analysis. Results: We found that GO coating with a hydrophilic feature is more biocompatible than other surfaces as observed in case of fibroblast cells. We have shown that wettability-controlled by GO deposition-influences biocompatibilities and antibacterial effect of biomaterial surfaces. Discussion: Measuring the contact angle, it is found that contact angle for hydrophobic is increased to 150.590 and reduced to 11.580 by heat and argon plasma treatment, respectively, from 75.880 that was initially in the case of hydrophobic surface. XPS analysis confirmed various oxygen-containing functional groups transforming as deposited hydrophobic surface into superhydrophobic and hydrophilic surface. Thus, we have proposed a new, direct, cost-effective, and highly productive method for the synthesis of rGO and GO-with various surface properties-for biological applications. Similarly, for the dental implant application, the Streptococcus mutans was used as an antibacterial effect and found that S. mutans grows slowly on hydrophilic surface. Thus, antibacterial effect was prominent on GO with hydrophilic surface.


Assuntos
Atmosfera/química , Grafite/síntese química , Gases em Plasma/farmacologia , Animais , Morte Celular/efeitos dos fármacos , Linhagem Celular , Grafite/química , Camundongos , Viabilidade Microbiana/efeitos dos fármacos , Oxirredução , Streptococcus mutans/efeitos dos fármacos , Água , Molhabilidade
4.
Environ Sci Process Impacts ; 22(8): 1759-1767, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32697206

RESUMO

Magnesium and calcium chloride salts contribute to the global atmospheric aerosol burden via emission of sea spray and mineral dust. Their influence on aerosol hygroscopicity and cloud forming potential is important but uncertain with ambiguities between results reported in the literature. To address this, we have conducted measurements of the hygroscopic growth and critical supersaturation of dried, size selected nano-particles made from aqueous solution droplets of MgCl2 and CaCl2, respectively, and compare experimentally derived values with results from state-of-the-art thermodynamic modelling. It is characteristic of both MgCl2 and CaCl2 salts that they bind water in the form of hydrates under a range of ambient conditions. We discuss how hydrate formation affects the particles' water uptake and provide an expression for hydrate correction factors needed in calculations of hygroscopic growth factors, critical super-saturations, and derived κ values of particles containing hydrate forming salts. We demonstrate the importance of accounting for hydrate forming salts when predicting hygroscopic properties of sea spray aerosol.


Assuntos
Sais , Água , Aerossóis , Poeira , Molhabilidade
5.
J Environ Sci (China) ; 95: 65-72, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653194

RESUMO

Mineral dust, soil, and sea salt aerosols are among the most abundant primary inorganic aerosols in the atmosphere, and their hygroscopicity affects the hydrological cycle and global climate. We investigated the hygroscopic behaviors of six Na- and K-containing salts commonly found in those primary organic aerosols. Their hygroscopic growths as a function of relative humidity (RH) agree well with thermodynamic model prediction. Temperature dependence of deliquescence RH (DRH) values for five of those salts was also investigated, which are comparable to those in literature within 1%-2% RH, most showing negative dependence on temperature. Hygroscopic growth curves of real-world soil and sea salt samples were also measured. The hygroscopic growths of two more-hydroscopic saline soil samples and of sea salt can be predicted by the thermodynamic model based on the measured water-soluble ionic composition. The substantial amounts of water-soluble ions, including Na+ and K+, in saline soil samples imply that even nascent saline soil samples are quite hygroscopic at high-RH (>80%) conditions. For three less-hygroscopic dust samples, however, measurements showed higher water uptake ability than that predicted by the thermodynamic model. The small amount of water taken up by less-hygroscopic dust samples suggests that dust particles might contain thin layers of water even to very low RH. The results of this study provide a comprehensive characterization of the hygroscopicity of Na- and K-containing salts as related to their roles in the hygroscopic behaviors of saline mineral dusts and sea salt aerosols.


Assuntos
Poluentes Atmosféricos/análise , Poeira , Aerossóis/análise , Minerais , Potássio , Sais , Sódio , Molhabilidade
6.
Int J Nanomedicine ; 15: 4471-4481, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606689

RESUMO

Background: Ineffective integration has been recognized as one of the major causes of early orthopedic failure of titanium-based implants. One strategy to address this problem is to develop modified titanium surfaces that promote osteoblast differentiation. This study explored titanium surfaces modified with TiO2 nanotubes (TiO2 NTs) capable of localized drug delivery into bone and enhanced osteoblast cell differentiation. Materials and Methods: Briefly, TiO2 NTs were subjected to anodic oxidation and loaded with Metformin, a widely used diabetes drug. To create surfaces with sustainable drug-eluting characteristics, TiO2 NTs were spin coated with a thin layer of chitosan. The surfaces were characterized via scanning electron microscopy, atomic force microscopy, and contact angle measurements. The surfaces were then exposed to mesenchymal bone marrow stem cells (MSCs) to evaluate cell adhesion, growth, differentiation, and morphology on the modified surfaces. Results: A noticeable increase in drug release time (3 days vs 20 days) and a decrease in burst release characteristics (85% to 7%) was observed in coated samples as compared to uncoated samples, respectively. Chitosan-coated TiO2 NTs exhibited a considerable enhancement in cell adhesion, proliferation, and genetic expression of type I collagen, and alkaline phosphatase activity as compared to uncoated TiO2 NTs. Conclusion: TiO2 NT surfaces with a chitosan coating are capable of delivering Metformin to a bone site over a sustained period of time with the potential to enhance MSCs cell attachment, proliferation, and differentiation.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Quitosana/química , Liberação Controlada de Fármacos , Metformina/farmacologia , Nanotubos/química , Osteoblastos/citologia , Titânio/química , Fosfatase Alcalina/metabolismo , Animais , Adesão Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Humanos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Nanotubos/ultraestrutura , Osteoblastos/efeitos dos fármacos , Osteoblastos/ultraestrutura , Osteogênese/efeitos dos fármacos , Ratos Wistar , Molhabilidade
7.
J Orthod ; 47(3): 223-231, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32615846

RESUMO

OBJECTIVE: The characterisation of surface roughness and energy of contemporary thermoplastic materials used in manufacturing of orthodontic aligners. DESIGN: In vitro, laboratory study. MATERIALS AND METHODS: Four commercially available thermoplastic materials were selected (CA-medium/CAM, Essix-copopyester/COP, Duran/DUR and Erkodur/ERK). Five disks from each, as received, material were tested and subjected to: (1) reflected light microscopy; (2) optical profilometry for the estimation of Sa, Sz, Sq, Sdr, Sc, Sv surface roughness parameters (n = 5); and (3) contact angle measurements with a Zisman series of liquids for the estimation of critical surface tension (γC), total work of adhesion (WA), as well as the work of adhesion due to polar (WP) and dispersion (WD) components employing the Zisman method (n = 5/liquid). Thermoformed disks were prepared against a dental stone model and the roughness parameters were calculated again Statistical analysis was performed by one-way ANOVA/ Tukey multiple comparison test and t-test (a = 0.05). RESULTS: Microscopic and profilometric analyses revealed a smooth surface texture in the as-received materials, but a very rough texture after thermoforming, with insignificant differences within each state. Significant differences in the as-received state were found in the surface energy parameters; CAM showed the lowest γC and the highest WA, WP, WD, whereas ERK with the highest γC demonstrated lower WA. COP and DUR were ranked in an intermediate group regarding γC, with a statistically significant difference in WA between them, mainly attributed to the lower WP of the former. CONCLUSION: Given the differences in surface energy parameters and the lack of roughness differences within the as received or thermoformed groups, it may be concluded that variations in the plaque retaining capacity are anticipated, determined by γC, WA and the WP, WD components.


Assuntos
Subunidade gama Comum de Receptores de Interleucina , Teste de Materiais , Propriedades de Superfície , Molhabilidade
8.
Chemosphere ; 260: 127586, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32693257

RESUMO

Removing contaminants from wastewater is critical towards resolving global water pollution problems. However, the variety of oily contaminants composition, and the unsatisfactory performance and efficiency of current separation systems are still big challenges, thus developing efficient and scalable oil-water separation (OWS) methods is needed. Here, the performance of a novel pilot-scale oil-water separator skimmer (OWSS) prototype is fully investigated using an upflow fixed bed column system packed with polypropylene (PP) fibrous sorbent materials for dual continuous OWS and in situ oils/organic solvents recovery. The mechanism of oil sorption by the PP fibrous sorbents, as well as capillary and vacuum assisted oil flow within the inter-fiber voids is fully explored. A series of pilot-scale column experiments were performed with different bed heights (7.5-30 cm) and using different types of oil/solvent in order to determine their influence on the oil flux, OWS efficiency and recovered organic solvent purity. The OWSS provided excellent and stable performance. A trade-off relationship between oil flux and OWS efficiency can be obtained: The maximum flux was attained at the lowest sorbent bed height (7.5 cm), while the maximum OWS efficiency (>99%) was achieved at the highest sorbent bed height (30 cm). The materials' morphology and wettability were examined showing outstanding stability and recyclability, which demonstrates their efficient integration into the overall OWSS. This study is expected to provide significant insights into the feasibility and scalability of an advanced, environmentally friendly, and relatively cost-effective OWS system, towards promising industrial implementation to overcome large-scale oil spill cleanup and oily wastewater treatment shortcomings.


Assuntos
Poluição por Petróleo/análise , Polipropilenos/química , Solventes/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Desenho de Equipamento , Interações Hidrofóbicas e Hidrofílicas , Projetos Piloto , Purificação da Água/instrumentação , Molhabilidade
9.
PLoS One ; 15(7): e0236837, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730369

RESUMO

Recent developments propose renewed use of surface-modified nanoparticles (NPs) for enhanced oil recovery (EOR) due to improved stability and reduced porous media retention. The enhanced surface properties render the nanoparticles more suitable compared to bare nanoparticles, for increasing the displacement efficiency of waterflooding. However, the EOR mechanisms using NPs are still not well established. This work investigates the effect of in-situ surface-modified silica nanoparticles (SiO2 NPs) on interfacial tension (IFT) and wettability behavior as a prevailing oil recovery mechanism. For this purpose, the nanoparticles have been synthesized via a one-step sol-gel method using surface-modification agents, including Triton X-100 (non-ionic surfactant) and polyethylene glycol (polymer), and characterized using various techniques. These results exhibit the well-defined spherical particles, particularly in the presence of Triton X-100 (TX-100), with particle diameter between 13 to 27 nm. To this end, SiO2 nanofluids were formed by dispersing nanoparticles (0.05 wt.%, 0.075 wt.%, 0.1 wt.%, and 0.2 wt.%) in 3 wt.% NaCl to study the impact of surface functionalization on the stability of the nanoparticle suspension. The optimal stability conditions were obtained at 0.1 wt.% SiO2 NPs at a basic pH of 10 and 9.5 for TX-100/ SiO2 and PEG/SiO nanofluids, respectively. Finally, the surface-treated SiO2 nanoparticles were found to change the wettability of treated (oil-wet) surface into water-wet by altering the contact angle from 130° to 78° (in case of TX-100/SiO2) measured against glass surface representing carbonate reservoir rock. IFT results also reveal that the surfactant treatment greatly reduced the oil-water IFT by 30%, compared to other applied NPs. These experimental results suggest that the use of surface-modified SiO2 nanoparticles could facilitate the displacement efficiency by reducing IFT and altering the wettability of carbonate reservoir towards water-wet, which is attributed to more homogeneity and better dispersion of surface-treated silica NPs compared to bare-silica NPs.


Assuntos
Nanopartículas/química , Óleos/isolamento & purificação , Dióxido de Silício/química , Tensoativos/química , Óleos/análise , Óleos/química , Tensão Superficial , Molhabilidade
10.
J Oral Sci ; 62(3): 259-264, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32581175

RESUMO

In this study, the wettability, cell viability, and roughness of an experimental dense bovine hydroxyapatite [Ca10(PO4)6(OH)2] ceramic block were evaluated so that, in the future, it could be used as a base material for dental implants. The results to commercial zirconia and a commercially pure titanium (Ti) alloy were compared. The surface roughness and contact angles were measured. An in vitro evaluation was conducted by means of tests in which pre-osteoblastic MC3T3-E1 cells were placed in indirect and direct contact with these materials. For cell viability, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and crystal violet test were conducted. A qualitative analysis was conducted using variable pressure scanning electron microscopy (SEM). No statistically significant differences were observed in wettability and roughness tests among the groups. In both the MTT assay and crystal violet test, all groups demonstrated satisfactory results without cytotoxicity. SEM showed cell adhesion and cell proliferation results on the material surfaces after 24 h and 48 h. In conclusion, this dense Ca10 (PO4)6(OH)2 ceramic can be considered as a potential biocompatible material.


Assuntos
Cerâmica , Durapatita , Animais , Bovinos , Proliferação de Células , Teste de Materiais , Microscopia Eletrônica de Varredura , Propriedades de Superfície , Titânio , Molhabilidade
11.
Chemosphere ; 257: 127214, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32505039

RESUMO

Reverse Osmosis (RO) desalination is an important step of wastewater reuse as it can remove salts and trace contaminants. However, RO also generates high salinity brines that need to be dealt with. Membrane distillation (MD), a process largely unaffected by salinity, provides a way to treat desalination brines up to high water recovery and has been proposed as a solution for RO brine management. However, pore wetting of membranes in MD is one of the major hurdles that prevents its implementation in wastewater treatment systems, as amphiphilic organic compounds present in wastewater can lead to pore wetting and loss of selectivity over time. The objective of this study was to identify a pre-treatment strategy to prevent wetting in MD treatment of municipal wastewater RO brines. We compared three pre-treatments with different separation or removal mechanisms: foam fractionation, advanced oxidation, and ultrafiltration. We evaluated membrane wetting by measuring the change in conductivity in the distillate and identified the most effective pre-treatment to prevent wetting in MD. The results show that wetting is prevented by pre-treating the brine with foam fractionation. The effectiveness of foam fractionation as a wetting control strategy was confirmed for a high wetting propensity synthetic water using sodium dodecyl sulfate as a model wetting compound. Finally, the effect of the pre-treatments on the desalination brine was evaluated to understand the nature of the compounds removed by each treatment. The results of this study will help implement MD as a treatment process for desalination brines in municipal wastewater reuse systems.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Destilação , Membranas Artificiais , Osmose , Oxirredução , Salinidade , Sais , Águas Residuárias , Água , Purificação da Água/métodos , Molhabilidade
12.
AAPS PharmSciTech ; 21(5): 162, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32488761

RESUMO

Hyaluronic acid (HA) is widely used to treat various ocular diseases like dry eye syndrome, keratoconus, and other corneal epithelial injuries. The currently available eye drop solutions need frequent doses affecting the routine life style of patients. In this work, the silicone contact lens was designed to entrap HA and Pluronic®F127 to improve the wettability of the contact lens to treat various ocular diseases. The soaking method (HA-SM) was compared with the direct entrapment (DL-HA-PI) technique. The HA-Pluronic®F127-laden contact lenses (DL-HA-PI) showed acceptable optical transmittance with improved swelling (water content) properties. The in vitro release data showed high burst release with HA-SM contact lenses (12-36 h), while DL-HA-PI contact lenses showed prolong release up to 96 h. The in vivo release in the rabbit tear fluid showed high HA concentration (tear fluid) with DL-HA-PI contact lenses in comparison to the HA-SM contact lenses. The DL-HA-PI-3 batch with Pluronic®F127 showed more promising results in schirmer strip study in comparison to DL-HA-3 batch (without Pluronic®F127). The presence of Pluronic®F127 with HA showed high potential to improve hydration property of the contact lens. The corneal healing model showed reduction in the ocular inflammatory symptoms with DL-HA-PI-3 batch, thus demonstrating the potential of HA and Pluronic®F127 to be used in various ocular diseases.


Assuntos
Lentes de Contato Hidrofílicas , Epitélio Anterior/patologia , Ácido Hialurônico/química , Poloxâmero/química , Animais , Sistemas de Liberação de Medicamentos , Feminino , Humanos , Ceratite/fisiopatologia , Masculino , Coelhos , Molhabilidade , Cicatrização
13.
Food Chem ; 330: 127325, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32569939

RESUMO

In order to develop natural, food-grade particles as emulsifiers, wet-milled has been conducted to obtain apple pomace particles in varying sizes. Structural characteristics, physicochemical properties and Pickering emulsifying potential of the particle in different sizes were investigated. Particle size of apple pomace was gradually reduced from 12.9 µm to 550 nm during 8 h milling. With the decrease of particles size, the morphology became less angular. Meanwhile, some insoluble dietary fibers transformed into soluble ones, and the wettability tended to be hydrophilic, therefore, the water and oil holding capacities and free-radical-scavenging capacities increased. The properties of Pickering emulsions stabilized by wet-milled apple pomace particles in different sizes were then investigated. The decrease of particle size resulted in the size reduction of emulsion droplets, and gave rise to enhance gel-like properties and antioxidative activities of emulsions. The results demonstrated promising prospect of wet-milled apple pomace particles as emulsifiers in food industry.


Assuntos
Emulsificantes/química , Emulsões/química , Malus/química , Fibras na Dieta , Depuradores de Radicais Livres/química , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , Água/química , Molhabilidade
14.
Proc Natl Acad Sci U S A ; 117(25): 13901-13907, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32513723

RESUMO

Many biological surfaces of animals and plants (e.g., bird feathers, insect wings, plant leaves, etc.) are superhydrophobic with rough surfaces at different length scales. Previous studies have focused on a simple drop-bouncing behavior on biological surfaces with low-speed impacts. However, we observed that an impacting drop at high speeds exhibits more complicated dynamics with unexpected shock-like patterns: Hundreds of shock-like waves are formed on the spreading drop, and the drop is then abruptly fragmented along with multiple nucleating holes. Such drop dynamics result in the rapid retraction of the spreading drop and thereby a more than twofold decrease in contact time. Our results may shed light on potential biological advantages of hypothermia risk reduction for endothermic animals and spore spreading enhancement for fungi via wave-induced drop fragmentation.


Assuntos
Plumas/química , Modelos Teóricos , Folhas de Planta/química , Chuva , Molhabilidade , Asas de Animais/química , Animais , Aves , Plumas/ultraestrutura , Hidrodinâmica , Insetos , Folhas de Planta/ultraestrutura , Tempo , Asas de Animais/ultraestrutura
15.
J Esthet Restor Dent ; 32(5): 521-529, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32598095

RESUMO

OBJECTIVE: To evaluate the effects of human saliva decontamination protocols on bond strength of resin cement to zirconia (Y-PSZ), wettability, and microbial decontamination. MATERIALS AND METHODS: Zirconia plates were sandblasted and divided into (a) not contaminated, (b) contaminated with human saliva and: (c) not cleaned, (d) cleaned with air-water spray, (e) cleaned with 70% ethanol, (f) cleaned with Ivoclean, or (g) cleaned with nonthermal atmospheric plasma (NTAP). The wettability and microbial decontamination of the surfaces were determined after saliva contamination or cleaning. Monobond Plus (Ivoclar Vivadent) was applied after cleaning, followed by Variolink LC (Ivoclar Vivadent). The samples were stored 1 week before shear bond strength (SBS) testing, and data (SBS and wettability) were analyzed by one-way analysis of variance and Tukey test (α = .05). RESULTS: Saliva contamination reduced SBS to zirconia compared to not contaminated. Both Ivoclean and NTAP produced higher SBS compared to not cleaned and were not significantly different from the not contaminated. Ivoclean produced the highest contact angle, and NTAP the lowest. With the exception of using just water-spray, all cleaning protocols decontaminated the specimens. CONCLUSIONS: Both Ivoclean and NTAP overcame the effects of saliva contamination, producing an SBS to zirconia comparable to the positive control. CLINICAL SIGNIFICANCE: Dental ceramics should be cleaned prior to resin cementation to eliminate the effects of human saliva contamination, and Ivoclean and NTAP are considered suitable materials for this purpose.


Assuntos
Colagem Dentária , Cerâmica , Descontaminação , Análise do Estresse Dentário , Humanos , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície , Molhabilidade , Zircônio
16.
Environ Sci Pollut Res Int ; 27(23): 28949-28961, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32418110

RESUMO

This study is anchored on the use of an eco-friendly effective plasma technique and cationization treatment to improve the hydrophobic nature of polyester (PET) fabric by incorporating hydrophilic functional groups onto the PET surface. The PET surface was initially treated with three different plasma gases prior to cationization treatment with quaternary ammonium salt (Quat 188). Madder roots were used, to produce natural dyes for the green coloration of PET fabrics in both dyeing and printing processes. The color strength (K/S) was measured to study the influence of both plasma gases and the cationization treatment on the coloration of PET fabric. Exposure to nitrogen plasma gases prior to the cationization treatment showed promising results for efficient PET coloration, resulting in the selection of nitrogen as a working gas at a flow rate of 3 l/min. The results also demonstrated that by combining the nitrogen plasma technique and cationization treatment, PET fabric with a highly effective surface was obtained, resulting in improved coloration, wettability, tensile strength, and roughness properties.


Assuntos
Poliésteres , Têxteis , Cor , Corantes , Molhabilidade
17.
Sci Total Environ ; 734: 139318, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32454334

RESUMO

Amino acids are important water-soluble nitrogen-containing compounds in atmospheric aerosols. They can be involved in cloud formation due to their hygroscopicity and have significant influences on the hygroscopicity of inorganic compounds, which have not yet been well characterized. In this work, the hygroscopic properties of three amino acids, including aspartic acid, glutamine, and serine, as well as their mixtures with ammonium sulfate (AS) were investigated using a hygroscopicity tandem differential mobility analyzer (HTDMA) system. The gradual water uptake of aspartic acid, glutamine and serine particles indicates that they exist as liquid phase at low RH. When mixing either aspartic acid or glutamine with AS by mass ratio of 1:3, we observed a clear phase transition but with a lower deliquescence relative humidity (DRH) with respect to that of pure AS. This suggests the crystallization of AS in the presence of each of these two amino acids. However, as the mass fractions of these two amino acids increased in the mixed particles, the deliquescence transition process was not obvious. In contrast, the crystallization of AS was efficiently hampered even at low content (i.e., 25% by mass) of serine in the mixed particles. The Zdanovskii-Stokes-Robinson (ZSR) method in general underestimated the hygroscopic growth of any mixtures at RH below 79% (prior to AS deliquescence), suggesting both amino acid and the partially dissolved AS contributed the overall hygroscopicity at RH in this range. Relatively good agreements were reached between the measurements and model predictions using the Extended Aerosol Inorganic Model (E-AIM) assuming solid state AS in the mixed particles for 1:3 aspartic acid-AS and glutamine-AS systems. However, the model failed to simulate the water uptake behaviors of any other systems. It demonstrates that the interactions between components within the aerosols have a significant effect on the phase state of the mixed particles.


Assuntos
Molhabilidade , Aerossóis , Aminoácidos , Sulfato de Amônio , Água
18.
Food Chem ; 328: 126768, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32470772

RESUMO

A colorimetric pH indicator was developed using nanofibers of poly(lactic acid) (PLA) and polyethylene oxide (PEO) combined with biomass of the microalga Spirulina sp. LEB 18. This study evaluates the potential use of microalgal biomass encapsulated in polymer nanofibers to develop a colorimetric pH indicator. Nanofibers containing the biomass were exposed to solutions with different pH values (pH 1-10), and color variations were measured using a colorimeter. The wettability analysis of the nanofibers showed hydrophilicity (zero angle with water), which allows ions to interact with the biomass, indicating a fast color response as a function of pH. When subjected to pH variations, indicators containing 1, 2 or 3% (w v-1) of biomass provided ΔΕ values >12, indicating an absolute difference in color. Therefore, this innovative material has the potential to be applied as a intelligent indicator to verify food quality through a visual signal of the product condition.


Assuntos
Colorimetria/métodos , Nanofibras/química , Spirulina/fisiologia , Biomassa , Cor , Concentração de Íons de Hidrogênio , Poliésteres/química , Polietilenoglicóis/química , Molhabilidade
19.
Phys Chem Chem Phys ; 22(20): 11327-11336, 2020 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-32406900

RESUMO

Aerosol dynamics is important to quantify in drug delivery to the lungs with the aim of delivering therapeutics to a target location and optimising drug efficacy. The macrocycle (2-hydroxypropyl)-ß-cyclodextrin (2-HP-ß-CD) is thought to alleviate symptoms associated with neurodegenerative diseases when inhaled but the hygroscopic response is not well understood. Here we measure the hygroscopic growth of individual aqueous aerosol containing 2-HP-ß-CD in optical tweezers through analysis of morphology-dependent resonances arising in Raman spectra. Droplets are analysed in the size range of 3-5 µm in radius. The evolving radius and refractive index of each droplet are measured in response to change in relative humidity from 98-20% to determine mass and radius based hygroscopic growth factors, and compared with dynamic vapour sorption measurements. Bulk solution refractive index and density measurements were used in accordance with the self-consistent Lorenz-Lorentz rule to determine melt solute and droplet properties. The refractive index of 2-HP-ß-CD was determined to be 1.520 ± 0.002 with a density of 1.389 ± 0.005 g cm-3. To our knowledge, we show the first aerosol measurements of 2-HP-ß-CD and determine hygroscopicity. By quantifying the hygroscopic growth and physicochemical properties of 2-HP-ß-CD, the impact of aerosol dynamics can be accounted for in tailoring drug formulations and informing models used to predict drug deposition patterns within the respiratory system.


Assuntos
2-Hidroxipropil-beta-Ciclodextrina/química , Aerossóis/química , Molhabilidade , Pinças Ópticas , Análise Espectral Raman
20.
Environ Sci Technol ; 54(12): 7097-7106, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32428397

RESUMO

The relative humidity (RH) history that manifests the cycling of dehydration (water evaporation) and hydration (water uptake) may affect particle-phase reactions, products from which have strong influences on the physical properties and thus climatic effects of atmospheric particles. Using single-trapped particles, we show herein hygroscopic growths of mixed particles with reactive species undergoing three types of RH cycles, simulating different degrees of particle-phase reactions in the atmosphere. The reactive species are the widely known α-dicarbonyl glyoxal (GLY), and five reduced nitrogenous species, ammonium sulfate (AS), glycine (GC), l-alanine (AL), dimethylamine (DMA), and diethylamine (DEA). The results showed that the mixed particles after reactions generally had altered efflorescence relative humidity (ERH) and deliquescence relative humidity (DRH) values and reduced hygroscopic growths at moderately high RH (>80%) conditions. For example, with an additional slow drying step, the mean mass growth factors at 90% RH during dehydration dropped from 2.56 to 2.02 for GC/GLY mixed particles and from 2.45 to 1.23 for AL/GLY mixed particles. The reduced hygroscopicity with more RH cycling will thus lead to less efficient light scattering of the mixed particles, thereby resulting in less cooling and exacerbating direct heating due to light absorption by the products formed.


Assuntos
Glioxal , Nitrogênio , Aerossóis , Umidade , Molhabilidade
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