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1.
J Environ Sci (China) ; 87: 250-259, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791498

RESUMO

Water-uptakes of pure sodium carbonate (Na2CO3), pure ß-alanine and internally mixed ß-alanine/Na2CO3 aerosol particles with different mole ratios are first monitored using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) technique. For pure Na2CO3 aerosol particles, combining the absorptions at 877 and 1422 cm-1 with abrupt water loss shows the efflorescence relative humidity (ERH) of 62.9%-51.9%. Upon humidifying, solid Na2CO3 firstly absorbs water to from Na2CO3·H2O crystal at 72.0% RH and then deliquesces at 84.5% RH (DRH). As for pure ß-alanine particles, the crystallization takes place in the range of 42.4%-33.2% RH and becomes droplets at ~88.2% RH. When ß-alanine is mixed with Na2CO3 at various mole ratios, it shows no efflorescence of Na2CO3 when ß-alanine to Na2CO3 mole ratio (OIR) is 2:1. For 1:1 and 1:2 ß-alanine/Na2CO3 aerosols, the ERHs of Na2CO3 are 51.8%-42.3% and 57.1%-42.3%, respectively. While ß-alanine crystal appears from 62.7% RH for 2:1 and 59.4% RH for both 1:1 and 1:2 particles and lasts to driest state. On hydration, the DRH is 44.7%-75.2% for Na2CO3 with the OIR of 1:1 and 44.7%-69.0% for 1:2 mixture, and those of ß-alanine are 74.8% for 2:1 mixture and 68.9% for two others. After the first dehumidification-humidification, all the water contents decrease despite of constituent fraction. And at ~92% RH, the remaining water contents are 92%, 89% and 82% at ~92% RH, corresponding to OIR of 2:1, 1:1 and 1:2 mixed system, respectively.


Assuntos
Alanina/química , Carbonatos/química , Modelos Químicos , Espectroscopia de Infravermelho com Transformada de Fourier , Molhabilidade
2.
J Environ Sci (China) ; 87: 49-59, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791517

RESUMO

To clarify the aerosol hygroscopic growth and optical properties of the Pearl River Delta (PRD) region, integrated observations were conducted in Heshan City of Guangdong Province from October 19 to November 17, 2014. The concentrations and chemical compositions of PM2.5, aerosol optical properties and meteorological parameters were measured. The mean value of PM2.5 increased from less than 35 (excellent) to 35-75 µg/m3 (good) and then to greater than 75 µg/m3 (pollution), corresponding to mean PM2.5 values of 24.9, 51.2, and 93.3 µg/m3, respectively. The aerosol scattering hygroscopic growth factor (f(RH = 80%)) values were 2.0, 2.12, and 2.18 for the excellent, good, and pollution levels, respectively. The atmospheric extinction coefficient (σext) and the absorption coefficient of aerosols (σap) increased, and the single scattering albedo (SSA) decreased from the excellent to the pollution levels. For different air mass sources, under excellent and good levels, the land air mass from northern Heshan had lower f(RH) and σsp values. In addition, the mixed aerosol from the sea and coastal cities had lower f(RH) and showed that the local sources of coastal cities have higher scattering characteristics in pollution periods.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental , China , Material Particulado/análise , Molhabilidade
3.
Nature ; 575(7781): 169-174, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31666696

RESUMO

Two dry surfaces can instantly adhere upon contact with each other through intermolecular forces such as hydrogen bonds, electrostatic interactions and van der Waals interactions1,2. However, such instant adhesion is challenging when wet surfaces such as body tissues are involved, because water separates the molecules of the two surfaces, preventing interactions3,4. Although tissue adhesives have potential advantages over suturing or stapling5,6, existing liquid or hydrogel tissue adhesives suffer from several limitations: weak bonding, low biological compatibility, poor mechanical match with tissues, and slow adhesion formation5-13. Here we propose an alternative tissue adhesive in the form of a dry double-sided tape (DST) made from a combination of a biopolymer (gelatin or chitosan) and crosslinked poly(acrylic acid) grafted with N-hydrosuccinimide ester. The adhesion mechanism of this DST relies on the removal of interfacial water from the tissue surface, resulting in fast temporary crosslinking to the surface. Subsequent covalent crosslinking with amine groups on the tissue surface further improves the adhesion stability and strength of the DST. In vitro mouse, in vivo rat and ex vivo porcine models show that the DST can achieve strong adhesion between diverse wet dynamic tissues and engineering solids within five seconds. The DST may be useful as a tissue adhesive and sealant, and in adhering wearable and implantable devices to wet tissues.


Assuntos
Adesividade , Adesivos/química , Coração , Pulmão , Próteses e Implantes , Estômago , Molhabilidade , Resinas Acrílicas/química , Animais , Quitosana/química , Reagentes para Ligações Cruzadas/química , Dessecação , Gelatina/química , Coração/anatomia & histologia , Hidrogéis/química , Ligações de Hidrogênio , Pulmão/anatomia & histologia , Pulmão/química , Camundongos , Ratos , Eletricidade Estática , Estômago/anatomia & histologia , Estômago/química , Suínos , Fatores de Tempo , Água/análise , Água/química , Dispositivos Eletrônicos Vestíveis
4.
Int J Nanomedicine ; 14: 6615-6630, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31695360

RESUMO

Background: Nanocomposites produced by reinforcement of polysaccharide matrix with nanoparticles are widely used in engineering of biomaterials. However, clinical applications of developed novel biomaterials are often limited due to their poor biocompatibility. Purpose: The aim of this work was to comprehensively assess biocompatibility of highly macroporous chitosan/agarose/nanohydroxyapatite bone scaffolds produced by a novel method combining freeze-drying with a foaming agent. Within these studies, blood plasma protein adsorption, osteoblast (MC3T3-E1 Subclone 4 and hFOB 1.19) adhesion and proliferation, and osteogenic differentiation of mesenchymal stem cells derived from bone marrow and adipose tissue were determined. The obtained results were also correlated with materials' surface chemistry and wettability to explain the observed protein and cellular response. Results: Obtained results clearly showed that the developed nanocomposite scaffolds were characterized by high biocompatibility and osteoconductivity. Importantly, the scaffolds also revealed osteoinductive properties since they have the ability to induce osteogenic differentiation (Runx2 synthesis) in undifferentiated mesenchymal stem cells. The surface of biomaterials is extremely hydrophilic, prone to protein adsorption with the highest affinity toward fibronectin binding, which allows for good osteoblast adhesion, spreading, and proliferation. Conclusion: Produced by a novel method, macroporous nanocomposite biomaterials have great potential to be used in regenerative medicine for acceleration of the bone healing process.


Assuntos
Regeneração Óssea , Osso e Ossos/fisiologia , Quitosana/química , Durapatita/química , Nanocompostos/química , Osteoblastos/citologia , Sefarose/química , Engenharia Tecidual/métodos , Tecidos Suporte/química , Adsorção , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Biomarcadores/metabolismo , Regeneração Óssea/efeitos dos fármacos , Osso e Ossos/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Cães , Feminino , Humanos , Células-Tronco Mesenquimais/citologia , Camundongos , Osteogênese/efeitos dos fármacos , Molhabilidade
5.
Environ Sci Technol ; 53(22): 13506-13513, 2019 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-31625726

RESUMO

Membrane distillation (MD) is a promising alternative approach for desalination, especially for high-salinity brines. Its application has been limited by its high operational cost because of the energy consumption required for hydraulic circulation and heating the entire circulating feed. Localized heating of the feed by Joule heating diminishes energy consumption, but the potential charging on the electrothermal material surface causes water splitting and membrane degradation in high-salinity environments. Herein, a novel reverse Joule-heating air gap MD method was designed in which an electrothermal material was placed at the air gap, isolating itself from saline water. Even though the Joule-heating layer was at the air gap side, 90.56% of heat flowed into the saline water for heating the feed. The opposite temperature gradient in the membrane matrix as opposed to conventional MD-mitigated membrane wetting was caused by capillary condensation. This novel electrothermal-driven MD configuration is worthy to be introduced into applications.


Assuntos
Destilação , Purificação da Água , Membranas Artificiais , Salinidade , Molhabilidade
6.
Int J Nanomedicine ; 14: 8149-8159, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31632024

RESUMO

Introduction: Recently several new approaches were emerging in bone tissue engineering to develop a substitute for remodelling the damaged tissue. In order to resemble the native extracellular matrix (ECM) of the human tissue, the bone scaffolds must possess necessary requirements like large surface area, interconnected pores and sufficient mechanical strength. Materials and methods: A novel bone scaffold has been developed using polyurethane (PE) added with wintergreen (WG) and titanium dioxide (TiO2). The developed nanocomposites were characterized through field emission scanning electron microscopy (FESEM), Fourier transform and infrared spectroscopy (FTIR), X-ray diffraction (XRD), contact angle measurement, thermogravimetric analysis (TGA), atomic force microscopy (AFM) and tensile testing. Furthermore, anticoagulant assays, cell viability analysis and calcium deposition were used to investigate the biological properties of the prepared hybrid nanocomposites. Results: FESEM depicted the reduced fibre diameter for the electrospun PE/WG and PE/WG/TiO2 than the pristine PE. The addition of WG and TiO2 resulted in the alteration in peak intensity of PE as revealed in the FTIR. Wettability measurements showed the PE/WG showed decreased wettability and the PE/WG/TiO2 exhibited improved wettability than the pristine PE. TGA measurements showed the improved thermal behaviour for the PE with the addition of WG and TiO2. Surface analysis indicated that the composite has a smoother surface rather than the pristine PE. Further, the incorporation of WG and TiO2 improved the anticoagulant nature of the pristine PE. In vitro cytotoxicity assay has been performed using fibroblast cells which revealed that the electrospun composites showed good cell attachment and proliferation after 5 days. Moreover, the bone apatite formation study revealed the enhanced deposition of calcium content in the fabricated composites than the pristine PE. Conclusion: Fabricated nanocomposites rendered improved physico-chemical properties, biocompatibility and calcium deposition which are conducive for bone tissue engineering.


Assuntos
Osso e Ossos/fisiologia , Poliuretanos/farmacologia , Engenharia Tecidual/métodos , Tecidos Suporte/química , Osso e Ossos/efeitos dos fármacos , Calcificação Fisiológica/efeitos dos fármacos , Cálcio/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Humanos , Teste de Materiais , Nanocompostos/química , Nanocompostos/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier , Resistência à Tração , Termogravimetria , Titânio/farmacologia , Molhabilidade , Difração de Raios X
7.
Environ Sci Technol ; 53(20): 11801-11809, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31535854

RESUMO

We report in this study a scalable and controllable approach for fabricating robust and high-performance superhydrophobic membranes for membrane distillation (MD). This novel approach combines electro-co-spinning/spraying (ES2) with chemical vapor welding and enables the formation of robust superhydrophobic (r-SH) membranes that are mechanically strong, highly porous, and robustly superhydrophobic. Compared with superhydrophobic membranes obtained using surface deposition of fluorinated nanoparticles, the r-SH membranes have more robust wetting properties and higher vapor permeability in MD. MD scaling experiments with sodium chloride and gypsum show that the r-SH membrane is highly effective in mitigating mineral scaling. Finally, we also discuss the mechanism of scaling resistance enabled by superhydrophobic membranes with a highlight on the roles of the surface-bound air layer in reducing the crystal-membrane contact area, nucleation propensity, and ion-membrane contact time.


Assuntos
Destilação , Purificação da Água , Membranas Artificiais , Porosidade , Molhabilidade
8.
Eur J Pharm Biopharm ; 144: 139-153, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31536784

RESUMO

Trehalose is commonly used as a protein stabilizer in spray dried protein formulations delivered via the pulmonary route. Spray dried trehalose formulations are highly hygroscopic, which makes them prone to deliquescence and recrystallization when exposed to moisture, leading to impairment in aerosolization performance. The main aim of this study was to investigate and compare the effect of hydrophobic amino acids (i.e. L-leucine and L-isoleucine) in enhancing aerosolization performance and in mitigating moisture-induced changes in spray dried trehalose formulations. Trehalose was spray dried with 20-60% w/w of amino acid (i.e. L-leucine or L-isoleucine). The spray dried formulations were stored at 25 °C/50% RH for 28 days. Solid state characterization and in vitro aerosolization performance studies were performed on the spray dried formulations before and after storage. The addition of 20-60% w/w of amino acid (i.e. L-leucine or L-isoleucine) improved the emitted fractions of spray dried trehalose formulations from a dry powder inhaler. However, ≥ 40% w/w of L-leucine/L-isoleucine was needed to prevent recrystallization of trehalose in the formulations when exposed to 25 °C/50% RH for 28 days. X-ray photoelectron spectroscopy (XPS) demonstrated that samples with 40-60% w/w L-isoleucine had more amino acid on the surfaces of the particles compared to their L-leucine counterparts. This may explain the greater ability of the L-isoleucine (40-60% w/w) samples to cope with elevated humidity compared to L-leucine samples of the same concentrations, as observed in the dynamic vapour sorption (DVS) studies. In conclusion, this study demonstrated that both L-leucine and L-isoleucine were effective in enhancing aerosolization performance and mitigating moisture-induced reduction in aerosolization performance in spray dried trehalose formulations. L-isoleucine proved to be superior to L-leucine in terms of its moisture protectant effect when incorporated at the same concentration in the formulations.


Assuntos
Aminoácidos/química , Trealose/química , Administração por Inalação , Aerossóis/química , Química Farmacêutica/métodos , Composição de Medicamentos/métodos , Inaladores de Pó Seco/métodos , Umidade , Interações Hidrofóbicas e Hidrofílicas , Leucina/química , Pós/química , Molhabilidade/efeitos dos fármacos
9.
J Prosthet Dent ; 122(4): 410.e1-410.e6, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31547953

RESUMO

STATEMENT OF PROBLEM: The wettability of the framework by liquid ceramics is important in ensuring a suitable bond between veneering ceramics and zirconia. PURPOSE: The purpose of this in vitro study was to examine the dependence of the wetting angle on temperature to determine the transition temperature from nonwettable to wettable states and to calculate the values of the relative wetting forces of the milled surfaces. MATERIAL AND METHODS: Fifty zirconia cylinders were divided into 5 groups (n=10) and subjected to the following treatments: milling, grinding, polishing, and airborne-particle abrasion with Al2O3 or SiC. After treatment, the specimens were rinsed, dried, and examined with respect to their wettability by liquid ceramics by using the automated Thermo-Wet test bench. The results were statistically analyzed by an ANOVA (α=.05). RESULTS: The most rapid wettability was obtained through airborne-particle abrasion with Al2O3 at 930 °C. Additionally, the highest relative bond strength (with respect to the machined surface) was obtained with Al2O3 abrasion. CONCLUSIONS: Because of variations in the wettability of the zirconia surface after different treatment methods, the firing temperature of the ceramic should also vary depending on the type of surface treatment applied. Thus, it is determined individually according to the chosen method.


Assuntos
Colagem Dentária , Porcelana Dentária , Óxido de Alumínio , Cerâmica , Materiais Dentários , Teste de Materiais , Propriedades de Superfície , Molhabilidade , Zircônio
10.
J Agric Food Chem ; 67(42): 11728-11740, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31525998

RESUMO

Pickering emulsions stabilized by food-grade particles have garnered increasing interest in recent years due to their promising applications in biorelated fields such as foods, cosmetics, and drug delivery. However, it remains a big challenge to formulate nanoscale Pickering emulsions from these edible particles. Herein we show that a new Pickering nanoemulsion that is stable, monodisperse, and controllable can be produced by employing the spherical micellar nanoparticles (EYPNs), self-assembled from the food-derived, amphiphilic egg yolk peptides, as an edible particulate emulsifier. As natural peptide-based nanoparticles, the EYPNs have a small particle size, intermediate wettability, high surface activity, and deformability at the interface, which enable the formation of stable Pickering nanodroplets with a mean dynamic light scattering diameter below 200 nm and a polydispersity index below 0.2. This nanoparticle system is versatile for different oil phases with various polarities and demonstrates the easy control of nanodroplet size through tuning the microfluidization conditions or the ratio of EYPNs to oil phase. These food-grade Pickering nanoemulsions, obtained when the internal phase is an edible vegetable oil, have superior stability during long-term storage and spray-drying based on the irreversible and compact adsorption of intact EYPNs at the nanodroplet surface. This is the first finding of a natural edible nano-Pickering emulsifier that can be used solely to make stable food Pickering nanoemulsions with the qualities of simplicity, versatility, low cost, and the possibility of controllable and mass production, which make them viable for many sustainable applications.


Assuntos
Gema de Ovo/química , Emulsificantes/química , Fixadores/química , Aditivos Alimentares/química , Peptídeos/química , Animais , Galinhas , Proteínas do Ovo/química , Óleos/química , Tamanho da Partícula , Água/química , Molhabilidade
11.
Mater Sci Eng C Mater Biol Appl ; 104: 109883, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500046

RESUMO

Surface charge on biomaterials is emerging as a crucial determinant of regulating cells responses impacting cells signaling in tissue treatment. The dynamic cell - material interaction is a complex process where surface properties in biomaterials are one of the most influencing parameters considering especially geometry, stiffness and surface charge. Therefore, a lot of effort in tissue engineering is focused on surface modifications with roughness and various coatings to control the surface potential. Importantly, charges allocated at the surface determine cells adhesion and later tissue development. Therefore, in this review, we discuss the influence of surface potential on cell attachment, mobility, proliferation, and differentiation on metals, polymer ceramics and their composites, including piezoelectric materials. The importance of surface charge is discussed in great details also for protein adsorption and wetting on modified and unmodified surfaces. We compare all characterization tools and theoretical descriptions for validation of surface potential on biomaterials. Many mechanisms governing cells responses are correlated especially surface charge topology and chemical composition. This review is a unique summary of cell culture study used to justify the effect of surface charge on cell behavior for healthcare materials.


Assuntos
Materiais Biocompatíveis/química , Animais , Adesão Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Humanos , Polímeros/química , Propriedades de Superfície , Engenharia Tecidual/métodos , Molhabilidade
12.
Mater Sci Eng C Mater Biol Appl ; 104: 109938, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499948

RESUMO

Surface based on polyelectrolytes functionalized with amino acids onto amino-terminated solid surfaces of silicon wafers was prepared, with the purpose of evaluate the chemical functionality of the polyelectrolyte films in adsorption and catalytic activity of an enzyme. In this work, the adsorption of the enzyme glucose 6-phosphate dehydrogenase from Leuconostoc mesenteroides (LmG6PD) was studied as model. The polyelectrolytes were obtained from poly (maleic anhydride-alt-vinylpyrrolidone) [poly(MA-alt-VP)] and functionalized with amino acids of different hydropathy index: glutamine (Gln), tyrosine (Tyr) and methionine (Met). The polyelectrolytes were adsorbed onto the amino-terminated silicon wafer at pH 3.5 and 4.5 and at low and high ionic strength. At low ionic strength and pH 3.5, the largest quantity of adsorbed polyelectrolyte was on the films containing glutamine moiety as the most hydrophilic amino acid in the side chain of polymer chain (5.88 mg/m2), whereas at high ionic strength and pH 4.5, the lowest quantity was in films containing tyrosine moiety in the side chain (1.88 mg/m2). The films were characterized by ellipsometry, contact angle measurements and atomic force microscopy (AFM). The polyelectrolyte films showed a moderate degree of hydrophobicity, the methionine derivative being the most hydrophobic film. With the aim of evaluate the effect of the amino acid moieties on the ability of the surface to adsorb enzymes, we study the activity of the enzyme on these surfaces. We observed that the polarity of the side chain of the amino acid in the polyelectrolyte affected the quantity of LmG6PD adsorbed, as well as its specific activity, showing that films prepared from poly(MA-alt-VP) functionalized with Met provide the best enzymatic performance. The results obtained demonstrated that the surfaces prepared from polyelectrolytes functionalized with amino acids could be an attractive and simple platform for the immobilization of enzymes, which could be of interest for biocatalysis applications.


Assuntos
Aminoácidos/metabolismo , Enzimas Imobilizadas/metabolismo , Polieletrólitos/metabolismo , Adsorção , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Glucosefosfato Desidrogenase/metabolismo , Leuconostoc/enzimologia , NAD/biossíntese , Polieletrólitos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Molhabilidade
13.
Mater Sci Eng C Mater Biol Appl ; 104: 109745, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499963

RESUMO

Chronic wounds are of high incidence, difficult to heal, and can cause serious consequences if not properly treated. Doxycycline (DCH) is a broad-spectrum antibiotic and matrix metalloproteinases inhibitor, which has prominent efficacy for chronic wound treatment. Topical DCH treatment is the common administration route for chronic wounds in clinic but may result in low therapeutic efficacy and cause skin irritation at high DCH concentration, since it is difficult to control local drug concentration in the wounds and maintain the effective DCH concentration for a long time. In this study, we prepared DCH-encapsulated polylactide (DCH/PLA) nanofibers by a simple electrospinning method. Imaging studies showed that smooth and continuous DCH/PLA nanofibers with homogeneous DCH distribution were obtained at varied DCH loading content in the range of 5-30%. Mechanical property, water vapour permeability and absorbency of these nanofibers could meet the requirement as wound dressings. By adjusting DCH loading content, the wettability of the nanofibers could be transferred from hydrophobic to hydrophilic, and the release rate of DCH could be controlled in a sustained manner from three days to two weeks. Results of cytotoxicity and antibacterial test indicated that DCH/PLA nanofibers showed good cytocompatibility to L929 mouse fibroblast cells and exhibited positive antibacterial activity against Escherichia coli, suggesting its ability to treat/prevent infectious wounds. For full-thickness wound treatment of diabetic rats, DCH/PLA nanofiber mats can speed up wound healing to a higher extent than topical DCH treatment, due to the sustained release of DCH with less side effects. Our results indicate that DCH/PLA nanofiber mats hold great potential as wound dressings for chronic wound treatment.


Assuntos
Doxiciclina/farmacologia , Nanofibras/química , Poliésteres/química , Cicatrização/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Morte Celular/efeitos dos fármacos , Linhagem Celular , Cristalização , Diabetes Mellitus Experimental/patologia , Liberação Controlada de Fármacos , Escherichia coli/efeitos dos fármacos , Cinética , Masculino , Camundongos , Nanofibras/ultraestrutura , Permeabilidade , Ratos Sprague-Dawley , Vapor , Molhabilidade
14.
Chemosphere ; 237: 124339, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31369903

RESUMO

A great prospect of sewage sludge self-recycling as a conditioner supports the research. A synergetic conditioning effect and mechanism were reflected after the synergistic conditioning experiment, and the corresponding separated experiment of biochar, K2FeO4 or acid treatment on WAS. All of the biochar, K2FeO4 and acid treatment could reduce the water content of sludge cake. Biochar had good effect on WAS settleability, although the influence of the biochar dosage was weak. Similar to K2FeO4, acid treatment also could reinforce the disintegration degree effectively, but it deteriorated the filter property of WAS. In the situation of synergistic condition, owing to the strong oxidation of K2FeO4, most of the sludge flocs was disintegrated, thus the settleability and filter property of WAS were still bad, even the biochar worked as a skeleton builder. It is encouraging to find that, even without acid treatment, there is a great decline of water content of sludge cake in the situation of synergistic condition.


Assuntos
Carvão Vegetal/química , Ferro/química , Esgotos/química , Eliminação de Resíduos Líquidos/métodos , Molhabilidade , Compostos de Ferro , Oxirredução , Compostos de Potássio , Água
15.
Molecules ; 24(16)2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31426303

RESUMO

The aim of this work was to compare the composition and physicochemical properties (SEM, XRD, solubility, swelling power, paste clarity, retrogradation, freeze-thaw stability, thermal property, and pasting property) of three Chinese yam (Dioscorea opposita Thunb.) starches (CYYS-1, CYYS-2, and CYYS-3) in Yunlong town, Haikou, Hainan Province, China. Our results show that all the CYYS gave a typical C-type X-ray diffraction pattern. The swelling power of CYYS varied from 10.79% to 30.34%, whereas solubility index was in the range of 7.84-4.55%. The freeze-thaw stability of each CYYS showed a contrary tendency with its amylose content. In addition, CYYS-3 showed the highest To (81.1 °C), Tp (84.8 °C), Tc (91.2 °C), and ΔH (14.1 J/g). The pasting temperature of CYYS-1 increased significantly with sucrose addition. NaCl could inhibit the swelling power of CYYS. There were significant decreases in pasting temperature and pasting time of CYYS when pH decreased.


Assuntos
Dioscorea/química , Cloreto de Sódio/química , Amido/química , Sacarose/química , Tecnologia de Alimentos/métodos , Liofilização , Temperatura Alta , Humanos , Microscopia Eletrônica de Varredura , Solubilidade , Amido/isolamento & purificação , Amido/ultraestrutura , Molhabilidade
16.
Carbohydr Polym ; 223: 115041, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31427026

RESUMO

For regenerating skeletal muscle tissue, cell alignment and myotube formation in a scaffold are required. To achieve this goal, various studies have focused on controlling the myoblast orientation by manipulating the topographical structures of scaffolds. In the present study, a combined process involving electrospinning and three-dimensional (3D) printing was used to obtain a hierarchical structure consisting of microscale and nanoscale topographical structures by using alginate nanofibers and a polycaprolactone (PCL)-fibrillated micro-strut. In the structure, a micropatterned PCL strut, which was obtained using 3D printing and a leaching process supplemented with a sacrificial material, was employed for not only enhancing the mechanical stability, but also inducing myotube formation, while highly aligned alginate nanofibers fabricated using a modified electrospinning process facilitated myoblast attachment and alignment. The cell orientation and myotube formation of C2C12 cells cultured in the 3D hierarchical structure were significantly better than those of two controls (alginate-coated PCL strut and alginate nanofiber-deposited PCL strut, not fibrillated). These results confirm that the hierarchical scaffold has immense potential as a biomaterial for muscle-tissue regeneration.


Assuntos
Alginatos/química , Diferenciação Celular/efeitos dos fármacos , Mioblastos/metabolismo , Nanofibras/química , Poliésteres/química , Tecidos Suporte , Animais , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Camundongos , Impressão Tridimensional , Tensão Superficial , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos , Viscosidade , Molhabilidade
17.
Nat Commun ; 10(1): 3220, 2019 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-31324790

RESUMO

Omniphobic membranes are attractive for membrane distillation (MD) because of their superior wetting resistance. However, a design framework for MD membrane remains incomplete, due to the complexity of omniphobic membrane fabrication and the lack of fundamental relationship between wetting resistance and water vapor permeability. Here we present a particle-free approach that enables rapid fabrication of monolithic omniphobic membranes for MD desalination. Our monolithic omniphobic membranes display excellent wetting resistance and water purification performance in MD desalination of hypersaline feedwater containing surfactants. We identify that a trade-off exists between wetting resistance and water vapor permeability of our monolithic MD membranes. Utilizing membranes with tunable wetting resistance and permeability, we elucidate the underlying mechanism of such trade-off. We envision that our fabrication method as well as the mechanistic insight into the wetting resistance-vapor permeability trade-off will pave the way for smart design of MD membranes in diverse water purification applications.


Assuntos
Destilação , Membranas Artificiais , Molhabilidade , Permeabilidade , Vapor , Purificação da Água/métodos
18.
Dent Mater J ; 38(5): 813-820, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31341146

RESUMO

Zirconia is commonly used in dental applications. It has been reported that surface-modified zirconia implants showed better performance in vivo than machined zirconia implants. Silk fibroin electrogel is a good candidate for controlled drug delivery; however, the use of silk fibroin electrogel on zirconia implants has not previously been reported. The aim of this study was to investigate a method to coat zirconia implants with silk fibroin electrogel and evaluate the mechanical and biological properties of the coating. The results show that the wettability of the coating was close to that of sand-blasted and acid-etched (SLA)-treated zirconia, and the bond strength was larger than that of the coating prepared from silk fibroin aqueous solution. ATR-FTIR spectra provided evidence that the secondary structure changed during the electrogelation process. Culturing cells on the coating revealed its nontoxicity to osteoblast-like cells. Thus, it can be suggested that a silk fibroin electrogel coating is a promising biocompatible and degradable drugdelivery material for zirconia implants.


Assuntos
Fibroínas , Seda , Propriedades de Superfície , Molhabilidade , Zircônio
19.
Mater Sci Eng C Mater Biol Appl ; 103: 109670, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31349450

RESUMO

The purpose of this research is to investigate the effect of different oxidation degrees and volume ratios of components on the physical properties and biocompatibility of an in situ cross-linking chitosan-hyaluronic acid-based hydrogel for skin wound healing applications. Carboxymethyl groups (-CH2COOH) were introduced to the polymer chain of chitosan, producing N,O - Carboxymethyl Chitosan (NOCC). Hyaluronic acid was oxidized to obtain aldehyde hyaluronic acid (AHA) with three oxidation degrees (AHA40, AHA50 and AHA60). The gelation was induced by forming Schiff base linkage between aldehyde groups of AHA and amino groups of NOCC. Then, the polysaccharide derivatives were combined at three NOCC:AHA volume ratios (3:7, 5:5 and 7:3) to form composite hydrogels without using any additional cross-linker. FT-IR analysis, surface morphology observation and wettability test, in vitro degradation test and rheological analysis were carried out to characterize the hydrogels. Additionally, in vitro cytotoxicity and in vivo wound healing evaluations were also conducted to study the biocompatibility of the composite. Our findings showed that when increasing the volume of NOCC, the homogeneity and hydrophobicity of the resulting hydrogels were also improved and their pore walls became thicker, leading to slower degradation rate. On the other hand, when raising the oxidation degree of AHA, the hydrophilicity of the gels decreased and less time was required to form the gel matrix. Besides, the obtained in vitro and in vivo results indicated that lower oxidation degree of AHA supports cell proliferation, cell attachment and wound healing process better. It is also concluded that NOCC-AHA40 5:5 hydrogel is most suitable for skin wound healing applications since it possesses superior morphology with high uniformity, favorable pore size and suitable density along with appropriate wettability. The NOCC-AHA gel matrix is expected to be used as a delivery system for other factors and employed as an effective bio-glue in further tissue engineering applications.


Assuntos
Quitosana , Ácido Hialurônico , Hidrogéis , Pele , Cicatrização/efeitos dos fármacos , Ferimentos e Lesões/terapia , Animais , Linhagem Celular , Quitosana/química , Quitosana/farmacologia , Ácido Hialurônico/química , Ácido Hialurônico/farmacologia , Hidrogéis/química , Hidrogéis/farmacologia , Camundongos , Oxirredução , Pele/lesões , Pele/metabolismo , Pele/patologia , Molhabilidade , Ferimentos e Lesões/metabolismo , Ferimentos e Lesões/patologia
20.
Mater Sci Eng C Mater Biol Appl ; 103: 109750, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31349498

RESUMO

Stents used for cardiovascular applications are composed of three main elements; a metal, polymer coating and the specific drug component. Nickel-based metals and polymer coatings currently used in the stent market have increased the recurrence of in-stent restenosis and stent failure due to inflammation. In this study, a Ti-8Mn alloy was used to fabricate a nanostructured surface that can be used for drug eluting stents to overcome the hypersensitivity of metals that are currently used in stent making as well as introducing a new built-in nano-drug reservoir instead of polymer coatings. Two different systems were studied: titanium dioxide nanotubes (NTs) and Ti-8Mn oxides NTs. The materials were characterized using field emission electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), roughness, wettability and surface energy measurements. Nanoindentation was used to evaluate the mechanical properties of the nanotubes as well as their stability. In-vitro cytotoxicity and cell proliferation assays were used to study the effect of the nanotubes on cell viability. Computational insights were also used to test the blood compatibility using band gap model analysis, comparing the band gap of the materials under investigation with that of the fibrinogen, in order to study the possibility of charge transfer that affects the blood clotting mechanism. In addition, the drug loading capacity of the materials was studied using acetyl salicylic acid as a drug model.


Assuntos
Stents Farmacológicos , Nanotubos/química , Ligas/química , Animais , Aspirina/farmacocinética , Células Cultivadas , Teoria da Densidade Funcional , Módulo de Elasticidade , Manganês/química , Camundongos , Microscopia Eletrônica de Varredura , Níquel , Oxirredução , Espectroscopia Fotoeletrônica , Pele/citologia , Espectrometria por Raios X , Propriedades de Superfície , Titânio , Molhabilidade , Difração de Raios X
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