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Hu, Haitao, Xiaohong Zhang, Dingping Zhang, Junguo Gao, Chunxiu Hu i Yayun Wang. "Study on the Nonlinear Conductivity of SiC/ZnO/Epoxy Resin Micro- and Nanocomposite Materials". Materials 12, nr 5 (5.03.2019): 761. http://dx.doi.org/10.3390/ma12050761.
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To investigate the inhomogeneous distribution of electric fields in insulating equipment and components, five nonlinear-conductance composite materials based on epoxy resin (EP) (nano-SiC/EP, nano-ZnO/EP, micro-ZnO/EP, nano-SiC/ZnO/EP, and nano-micro-SiC/ZnO/EP), were prepared using nano-SiC, nano-ZnO, and micro-ZnO particles as fillers. The mass fractions of the inorganic fillers were 1, 3, and 5 wt%, respectively. The direct current (DC) voltage characteristics of the composites showed that the electrical conductivities and nonlinear coefficients of the composites utilizing single-filler types increased with increasing inorganic filler content. Under the same conditions, the conductivity and nonlinear coefficient of SiC/EP were both larger than those of the nano-ZnO/EP and micro-ZnO/EP. However, the nonlinear coefficient of the composites was significantly affected by the simultaneous addition of the two inorganic fillers, micro-ZnO and nano-SiC. When the content ratio of micro-ZnO to nano-SiC was 2:3, the nonlinear coefficient of the composite reached a maximum value of 3.506, significantly higher than those of the other samples. Compared with the nano-SiC/EP, micro-ZnO/EP and nano-ZnO/EP composites with 5 wt% inorganic filler, the nonlinear coefficient of the two-filler composite was greater by a factor of 0.82, 2.48, and 5.01, respectively.
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Selvam, R., S. Ravi i K. Balasubramanian. "Mechanical Testing of Plastoceramic (nPMC Sheet- SiC Reinforced Polyester Nano Composite)". International Journal of Engineering & Technology 7, nr 3.12 (20.07.2018): 1195. http://dx.doi.org/10.14419/ijet.v7i3.12.17785.
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Concept of nano-composite Technology has gained greater momentum in its recent engineering applications. Recent works on Nano-composite technology have proved the viability of its use and its importance in modern engineering fields of applications particularly in the field of materials and manufacture. When dissimilar materials are used with different compositions to obtain newer nano- composite materials, it has lead to the production of novel products with unique properties. In the present study, the ceramic material SiC is used as reinforcement owing to its superior properties such as hardness, thermal conductivity and strength. And this has paved the way for using it in the making of polyester nano- composite sheet (nPMC) with aforementioned properties. Fabrication and characterization of Nano-composite sheet is carried out using a weight ratio of 30% so as to understand the molecular structure and mechanical behavior under external load. The synthetic procedure and characterization used in this study has made it possible to obtain SiC nano particles reinforced polyester nano-composites (nPMC) film with good thermal strength and chemical homogeneity over the traditional composite.
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Dayı, Burak, i Fikri Öcal. "Evaluation of the effects of whitening toothpaste containing nanohydroxyapatite on surface roughness and color change in restorative materials". PeerJ 11 (14.07.2023): e15692. http://dx.doi.org/10.7717/peerj.15692.
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Background The effects of whitening toothpastes containing nanohydroxyapatite on the surfaces of restorative materials are not well known. This study evaluated the changes in surface roughness and color of coffee-stained restorative materials after brushing with nanohydroxyapatite and other whitening toothpastes. Methods Disc-shaped specimens were formed using microhybrid, nanohybrid, and supra-nano-filled composite (n = 30) and stained with a coffee solution. A brushing simulation was applied with toothpastes containing nanohydroxyapatite (Dentiste Plus White), perlite (Signal White System) and hydrogen peroxide (Colgate Optic White) for 7, 15, and 30 days. Color and surface roughness measurements were taken before and after brushing. Color change (∆E00) was calculated using the CIEDE2000 system. Results Supra-nano-filled composite-Dentiste Plus White, supra-nano-filled composite-Colgate Optic White, and nanohybrid composite-Signal White System were the groups with the greatest color change observed on the 7th, 15th, and 30th days, respectively. The smallest color change was seen in the microhybrid composite-Signal White System, microhybrid composite-Dentiste Plus White, and nanohybrid composite-Dentiste Plus White groups on the 7th, 15th, and 30th days, respectively. No significant surface roughness changes were observed in the nanohybrid composite-Dentiste Plus White, supra-nano-filled composite-Colgate Optic White, supra-nano-filled composite-Dentiste Plus White, or supra-nano-filled composite-Signal White System groups. Conclusions Whitening toothpaste containing nanohydroxyapatite provided a high degree of color change in the short term and did not create significant surface roughness in nanohybrid or supra-nano-filled composites.
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Liang, Ji-Zhao. "Heat distortion temperature of PPS/PC blend, PPS/PC nanocomposite and PPS/PC/GF hybrid nanocomposite". Journal of Polymer Engineering 33, nr 6 (1.09.2013): 483–88. http://dx.doi.org/10.1515/polyeng-2013-0064.
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Abstract The polyphenylene sulfide (PPS) blended with polycarbonate (PC), reinforced glass fiber (GF) and nanometer calcium carbonate (nano-CaCO3) filled PPS ternary composite, as well as the PPS/PC/GF/nano-CaCO3 hybrid composite, were prepared by means of a twin-screw extruder, and the heat distortion temperature (Td) of these materials was measured to identify the influence of the PC and nano-CaCO3 content on the heatproof properties. The Td values for the PPS/PC blend were lower than that of the neat PPS, when the PC weight fraction (φPC) was less than 20%, and increased with increase in φPC. The Td values for the PPS/GF/nano-CaCO3 ternary composite, on which the particle surface was treated with a titanate coupler, were higher than that of the composite with the particle surface treated with a stearate coupler. When the nano-CaCO3 weight fraction (φf) was less than 6%, the Td values for the PPS/PC/GF/nano-CaCO3 hybrid composites increased with increasing φf; at greater than the maximum of 6%, Td decreased. There was a certain synergistic effect of the GF and nano-CaCO3 on the heatproof properties in the PPS/PC composite.
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Oleiwi, Jawad Kadhim, i Qahtan Adnan Hamad. "Studying the Mechanical Properties of Denture Base Materials Fabricated from Polymer Composite Materials". Al-Khwarizmi Engineering Journal 14, nr 3 (4.09.2018): 100–111. http://dx.doi.org/10.22153/https://doi.org/10.22153/kej.2018.01.006.
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In this research, the effect of adding two different types of reinforcing particles was investigated, which included: nano-zirconia (nano-ZrO2) particles and micro-lignin particles that were added with different volume fractions of 0.5%, 1%, 1.5% and 2% on the mechanical properties of polymer composite materials. They were prepared in this research, as a complete prosthesis and partial denture base materials was prepared, by using cold cure poly methyl methacrylate (PMMA) resin matrix. The composite specimens in this research consist of two groups according to the types of reinforced particles, were prepared by using casting methods, type (Hand Lay-Up) method. The first group consists of PMMA resin reinforced by (nano-ZrO2) particles, while the second group consists of PMMA resin reinforced by (micro-lignin) particles.
The mechanical tests performed in this research includedtensile test, compression test, impact test and hardness test. The results of this study showed that the values of tensile modulus of elasticity, compressive strength and hardness properties increased with increasing the volume fraction of these particles in PMMA composite materials. While, the values of tensile strength, elongation and impact strength properties decreased. Also, the addition of (nano-ZrO2) particles showed greater effect than that of (micro-lignin) particles in some properties of PMMA composite materials for prosthesis denture base materials specimens, while they have lower effect for the other properties.
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Oleiwi, Jawad Kadhim, i Qahtan Adnan Hamad. "Studying the Mechanical Properties of Denture Base Materials Fabricated from Polymer Composite Materials". Al-Khwarizmi Engineering Journal 14, nr 3 (4.09.2018): 100–111. http://dx.doi.org/10.22153/kej.2018.01.006.
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In this research, the effect of adding two different types of reinforcing particles was investigated, which included: nano-zirconia (nano-ZrO2) particles and micro-lignin particles that were added with different volume fractions of 0.5%, 1%, 1.5% and 2% on the mechanical properties of polymer composite materials. They were prepared in this research, as a complete prosthesis and partial denture base materials was prepared, by using cold cure poly methyl methacrylate (PMMA) resin matrix. The composite specimens in this research consist of two groups according to the types of reinforced particles, were prepared by using casting methods, type (Hand Lay-Up) method. The first group consists of PMMA resin reinforced by (nano-ZrO2) particles, while the second group consists of PMMA resin reinforced by (micro-lignin) particles.
The mechanical tests performed in this research includedtensile test, compression test, impact test and hardness test. The results of this study showed that the values of tensile modulus of elasticity, compressive strength and hardness properties increased with increasing the volume fraction of these particles in PMMA composite materials. While, the values of tensile strength, elongation and impact strength properties decreased. Also, the addition of (nano-ZrO2) particles showed greater effect than that of (micro-lignin) particles in some properties of PMMA composite materials for prosthesis denture base materials specimens, while they have lower effect for the other properties.
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Sudha, L. K., Roy Sukumar i K. Uma Rao. "Capacitance and Glass Transition Temperature of Nano Structured Alumina Polycarbonate Composites". Applied Mechanics and Materials 446-447 (listopad 2013): 73–78. http://dx.doi.org/10.4028/www.scientific.net/amm.446-447.73.
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This paper describes how glass transition temperature (Tg) and capacitance (Cp) of a nanomodified composite polymer changes as compared to that of its base polymer. Because of its versatile applications, polycarbonate materials (grade PC1100 and PC1220 respectively), which are commercially available, were chosen as the base polymer in this study and nanostructured alumina material was used as filler for fabricating the desired composites by varying the filler weight in the composite materials. The Tg of the composites has been evaluated by differential scanning calorimetry (DSC) technique and Cp of the composites are derived from AC conductivity measurements of the composites. Results show that the Tg decreases as a function of filler load in the composite material whereas capacitance of the composites increase with the filler load in the composites. A filler concentration equal to or greater than 5 wt% in the said composites, the Tg of the composites reduces upto 15°C, whereas Cp shoots up in the pico-farad range with the same level of filler load, as compare to base polymers.
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Bohinc, Klemen, Erna Tintor, Davor Kovačević, Rajko Vidrih, Anamarija Zore, Anže Abram, Željka Kojić, Marija Obradović, Valentina Veselinović i Olivera Dolić. "Bacterial Adhesion on Glass–Ionomer Cements and Micro/Nano Hybrid Composite Dental Surfaces". Coatings 11, nr 2 (16.02.2021): 235. http://dx.doi.org/10.3390/coatings11020235.
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Dental restorations need to reproduce the aspect of the natural teeth of the patient, and must be non-toxic, biocompatible, and have good mechanical properties so that they can last for longer. The aim of this study was to determine the extent of bacterial adhesion of Streptococcus mutans on four different dental material surfaces, i.e., two glass–ionomer cements (Fuji conventional and Fuji hybrid) and two ceramic composites (Micro hybrid composite and Nano hybrid composite). To understand the bacterial adhesion on these four different dental materials, various surface properties were measured: roughness, contact angle, CIE color parameters and zeta potential. We found that the greatest adhesion extent was obtained for the Nano hybrid composite surface. The pronounced adhesion is the interplay between the relatively high roughness and hydrophilicity of the Nano hybrid composite surface. Color changes upon immersing ceramic composites in red wine and black tea proved that both beverages adhered to them. Black tea adhered more intensively than wine, and showed a higher inhibitory effect on the growth of Streptococcus mutans and Staphylococcus aureus.
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Guo, Shu Qi. "Polymer-Derived Nano-Sized SiC-Containing ZrB2 Composites: Densification, Microstructure and Flexural Strength". Solid State Phenomena 281 (sierpień 2018): 355–60. http://dx.doi.org/10.4028/www.scientific.net/ssp.281.355.
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Silicon carbide (SiC)-containing zirconium diboride (ZrB2) composites have become an important class of ultra-high temperature ceramic materials for the thermal protection systems of re-entry hypersonic vehicles with sharp leading edge profiles. Previous studies in ZrB2-SiC composites showed that nano-sized SiC particles-containing ZrB2 composites had a greater strength and a better oxidation resistance compared to ZrB2-beased composites with micron-sized SiC particles. However, it is difficult for obtaining a homogenous microstructural ZrB2-based composite with nano-sized SiC particles because of agglomerates of the SiC particles. In this study, homogenously dispersed nano-sized SiC particles-containing ZrB2 composites were prepared using polymer-derived SiC-dispersed ZrB2 composite powders followed by hot pressing at different temperatures between 1750°C and 1900°C. The microstructure of the resulting composites was characterized by field emission scanning electron microscopy. Four-point flexural strength of the obtained composites was measured at room temperature. The effects of the sintering temperatures and SiC content on the microstructure and the flexural strength of the composites were discussed.
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Sridhar*, Atla, i K. Prasanna Lakshmi. "Characterization and Wear Properties of Al 7075/Sic/Gr Hybrid Composites". International Journal of Innovative Technology and Exploring Engineering 9, nr 2 (30.12.2019): 2942–47. http://dx.doi.org/10.35940/ijitee.b7948.129219.
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In this work, dry sliding wear properties of Al 7075 Al 7075+ 5 wt.% SiC, Al7075 + 5 wt.% SiC + X wt.% graphite (X=5-10) hybrid nano-composites were developed by the principle of powdered metallurgy (P / M). Al 7075 hybrid nano-composites are highly promising materials that would be desirable for a wide range of applications. Under dry sliding conditions, the tests were carried out on a pin-on-disk machine was used to assess the loss of wear on base metal, composite and hybrid composites were calculated by different normal loads (5–20 N), and sliding speeds (0.5 – 2 m/s) and sliding distances (500–2000 m). Micro-structural examination of base metal and composites were investigated using an Optical Microscope (OM) and scanning electron microscope (SEM). The hybrid nano-composites revealed those greatest improvements in tribological results with 5 wt. % Silicon Carbide and 10 wt. % Graphite. Main wearing mechanism for hybrid composite materials has been established to form lubricating layer on both the surface and specimen. From experimental outcomes, it has been found that wear resistance tends to increase as weight percentage of the reinforcement increases.
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Pawar, Sarika P. "Micro and Nano Fiber Composite Coatings". International Journal for Research in Applied Science and Engineering Technology 10, nr 6 (30.06.2022): 5160–74. http://dx.doi.org/10.22214/ijraset.2022.44634.
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Abstract: Environmental friendly products are becoming popular and acceptable in industries due to the global limitation to the amount of volatile organic compounds (VOCs) released into the atmosphere. Low VOC compounds and technologies are also becoming a choice in the coatings and paint industry. Coatings can be made from water or solvent. In coatings from water, we use water as the solvent, therefore coating called water based coating and in the case of solvent-borne coatings, we used organic or inorganic compounds as solvents, therefore this coating called as solvent borne coating. Among all different types of solvents water is the greatest choice among these low VOC technologies for usage as a solvent to manufacture chemical compounds and Paints and coatings. because water is often recognized as a low-cost, safe, non-toxic, easily available and ecologically friendly solvent. Also nanomaterials is new field in research and development of material science . Materials can be one dimensional such as small particles, materials can be two dimensional such as fibres. Therefore in two-dimensional materials such as fibres ( micro and nanofibers) use in many different applications such as medical, composites, aerospace, Building constructions etc. Nanofiber has the advantage of high surface area to volume ratio hence to decrease the coating defects. micro and nanofibers should be incorporated inside the coating matrix. This way one can improve the properties of water-based coatings. Hence low VOC solvent water with high surface area fibre is becoming a trend in composite coating and nanotechnology in fibres. This review provides information on Composite coatings, distinct fibres used in coatings and their applications, also effects of different aspect ratio of fibres on properties of coatings
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Song, Xupeng, Xiaofeng Xue, Wen Qi, Jin Zhang, Yang Zhou, Wei Yang, Yiran Zhang, Boyang Shen, Jun Lin i Xingming Bian. "Research on the Compound Optimization Method of the Electrical and Thermal Properties of SiC/EP Composite Insulating Material". Polymers 13, nr 19 (30.09.2021): 3369. http://dx.doi.org/10.3390/polym13193369.
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In this paper, in order to improve the electrical and thermal properties of SiC/EP composites, the methods of compounding different crystalline SiC and micro-nano SiC particles are used to optimize them. Under different compound ratios, the thermal conductivity and breakdown voltage parameters of the composite material were investigated. It was found that for the SiC/EP composite materials of different crystal types of SiC, when the ratio of α and β silicon carbide is 1:1, the electrical performance of the composite material is the best, and the breakdown strength can be increased by more than 10% compared with the composite material filled with single crystal particles. For micro-nano compound SiC/EP composites, different total filling amounts of SiC correspond to different optimal ratios of micro/nano particles. At the optimal ratio, the introduction of nanoparticles can increase the breakdown strength of the composite material by more than 10%. Compared with the compound of different crystalline SiC, the advantage is that the introduction of a small amount of nanoparticles can play a strong role in enhancing the break-down field strength. For the filled composite materials, the thermal conductivity mainly depends on whether an effective heat conduction channel can be constructed. Through experiments and finite element simulation calculations, it is found that the filler shape and particle size have a greater impact on the thermal conductivity of the composite material, when the filler shape is rounder, the composite material can more effectively construct the heat conduction channel.
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Natrayan, L., T. Sathish, S. Baskara Sethupathy, S. Sekar, Pravin P. Patil, G. Velmurugan i Hunde Hailu. "Interlaminar Shear, Bending, and Water Retention Behavior of Nano-SiO2 Filler-Incorporated Dharbai/Glass Fiber-Based Hybrid Composites under Cryogenic Environment". Adsorption Science & Technology 2022 (30.07.2022): 1–10. http://dx.doi.org/10.1155/2022/3810884.
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In current history, adding nanoscale and micron-sized filler materials to composite materials for fabrication has been a popular approach for improving the composite’s mechanical characteristics. Due to their lower friction coefficient, excellent mechanical strength modulus, and low moisture uptake, filler-based hybrid composite materials are replacing metallic materials. Glass/Dharbai hybrid composites with nano-SiO2 fillers have been created in this study. After manufacture, the composite materials were treated with liquid nitrogen at 177 K for various durations. Every sample material was cut according to ASTM standards to investigate mechanical features such as ILSS, impact test, and flexural strength. The broken composite specimen was studied using a scanning electron microscope. Water retention studies have been conducted under two distinct liquid solutions: tab or regular water and seawater. ILSS, flexural strength, and water retention were all greater in 4 wt.% of nanofiller-rich composites than in ordinary composites. Compared to 30 minutes, the 15-minute cryo-treated specimens provide the highest mechanical strength. On the other hand, the automobile, aviation, and shipbuilding sectors would benefit from a nanofiller-based composite.
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Zhang, Li, Mei Niu, Jin Ming Dai, Li Qiao Wei, Xu Guang Liu i Bing She Xu. "Effects of Different Factors on Antibacterial Properties of Crosslinked Chitosan-Coated Ag-Loading Nano-SiO2 Composites". Advanced Materials Research 535-537 (czerwiec 2012): 51–54. http://dx.doi.org/10.4028/www.scientific.net/amr.535-537.51.
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Chitosan (CTS) and Ag-loading nano-SiO2 (SLS) are excellent antibacterial materials. However, when used alone, these monocomponent antibacterial agents are sometimes far from meeting requirements in special conditions. In this study, crosslinked chitosan-coated Ag-loading nano-SiO2 composites (CCTS-SLS) were synthesized by adsorption crosslinking reaction. Then Escherichia coil (ATCC 8099) was taken as the experimental bacteria for antibacterial tests. The experimental results indicate that the mass ratio of SLS to chitosan had the greatest influences on the value of MIC (minimal inhibitory concentration) for CCTS-SLS composite. However, the heating temperature had a weak influence on the antibacterial performance of CCTS-SLS composite.
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Liu, Jin, Quan Dai, Michael D. Weir, Abraham Schneider, Charles Zhang, Gary D. Hack, Thomas W. Oates, Ke Zhang, Ang Li i Hockin H. K. Xu. "Biocompatible Nanocomposite Enhanced Osteogenic and Cementogenic Differentiation of Periodontal Ligament Stem Cells In Vitro for Periodontal Regeneration". Materials 13, nr 21 (4.11.2020): 4951. http://dx.doi.org/10.3390/ma13214951.
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Decays in the roots of teeth is prevalent in seniors as people live longer and retain more of their teeth to an old age, especially in patients with periodontal disease and gingival recession. The objectives of this study were to develop a biocompatible nanocomposite with nano-sized calcium fluoride particles (Nano-CaF2), and to investigate for the first time the effects on osteogenic and cementogenic induction of periodontal ligament stem cells (hPDLSCs) from human donors.Nano-CaF2 particles with a mean particle size of 53 nm were produced via a spray-drying machine.Nano-CaF2 was mingled into the composite at 0%, 10%, 15% and 20% by mass. Flexural strength (160 ± 10) MPa, elastic modulus (11.0 ± 0.5) GPa, and hardness (0.58 ± 0.03) GPa for Nano-CaF2 composite exceeded those of a commercial dental composite (p < 0.05). Calcium (Ca) and fluoride (F) ions were released steadily from the composite. Osteogenic genes were elevated for hPDLSCs growing on 20% Nano-CaF2. Alkaline phosphatase (ALP) peaked at 14 days. Collagen type 1 (COL1), runt-related transcription factor 2 (RUNX2) and osteopontin (OPN) peaked at 21 days. Cementogenic genes were also enhanced on 20% Nano-CaF2 composite, promoting cementum adherence protein (CAP), cementum protein 1 (CEMP1) and bone sialoprotein (BSP) expressions (p < 0.05). At 7, 14 and 21 days, the ALP activity of hPDLSCs on 20% Nano-CaF2 composite was 57-fold, 78-fold, and 55-fold greater than those of control, respectively (p < 0.05). Bone mineral secretion by hPDLSCs on 20% Nano-CaF2 composite was 2-fold that of control (p < 0.05). In conclusion, the novel Nano-CaF2 composite was biocompatible and supported hPDLSCs. Nano-CaF2 composite is promising to fill tooth root cavities and release Ca and F ions to enhance osteogenic and cementogenic induction of hPDLSCs and promote periodontium regeneration.
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Sivasaravanan, S., V. K. Bupesh Raja, S. Prabhu, S. Dineshkumar i Gokulaprasad. "Investigation of Mechanical Properties of Nano Sized Clay/LDH Particle as Hybrid Nano Composite Material". Applied Mechanics and Materials 766-767 (czerwiec 2015): 355–61. http://dx.doi.org/10.4028/www.scientific.net/amm.766-767.355.
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Usage of Hybrid nanocomposite materials provides a greater opportunity to replace the conventional materials due to their properties such as light weight and high strength to based on weight ratio. In this synergitic study, nanosized clay particle and layered double hydroxide particles are used. nanoclay and LDH particles were mixed on the bases of weight percentage (1wt% to 5wt%) by ultra sonication technique. The composite material was fabricated by one of the most common method known as hand lay-up technique. The composite materials was prepared in the form of plate with 4mm of thickness.The characterization of tensile and flexural property of the nanoclay, LDH and combination of both was analysis by tensile test using universal testing machine and three point bending test respectively. The tensile and three point bending test specimens were cut to size as per ASTM standard.The morphology of composite was studied using SEM analysis.
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Umar, MD, R. Muraliraja, V. S. Shaisundaram i Shiferaw Garoma Wayessa. "Influence of Future Material Nano-ZrO2 and Graphene on the Mechanical Properties of Al Composites". Journal of Nanomaterials 2022 (22.09.2022): 1–7. http://dx.doi.org/10.1155/2022/1454037.
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Recent developments in mechanical applications have led to the development of metal matrix composites, which represent the future of composite structures. Al7010 aluminium alloy matrix with nano-ZrO2 and graphene particle reinforced composite is created in this experiment. By adopting the stir casting procedure in two different casting, 2 percent reinforcement of zirconium dioxide and 1 percent of graphene is included in the composite materials. The composite’s metallurgical and mechanical characteristics are studied. The SEM image demonstrates uniform dispersion of the particles in the alloy matrix. The manufactured material’s ability to gather particulate matter is clearly found in SEM and EDS. The addition of zirconia particles works together to prevent the alloy matrix from dislocating, which increases the base material’s hardness as well as its tensile resistance. Similar results are also found in graphene-casting material. Results from tensile tests reveal that adding nano-zirconium dioxide particle (ZrO2) and graphene boosts the material’s tensile and hardness strength. In terms of the ultimate tensile strength (UTS), the Al7010/2% ZrO2 composite had a 6% increase and Al7010/1% graphene had a 5.5% increase above the Al7010 alloy. Compared to Al7010 alloy, the microhardness of Al7010/ZrO2 is 17.64% greater and Al7010/1% graphene is 14% greater.
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Panin, Sergey V., Lyudmila A. Kornienko, Vladislav O. Aleksenko, Larisa R. Ivanova, Sergey V. Shilko i Dmitriy G. Buslovich. "COMPARISON OF EFFECTIVENESS OF CARBON NANO- AND MICROFIBERS FOR FORMATION OF PHYSICAL-MECHANICAL AND TRIBOLOTECHNICAL PARAMETERS OF POLYMER COMPOSITES BASED ON HIGH MOLECULAR WEIGHT MATRIX". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 59, nr 9 (17.07.2018): 99. http://dx.doi.org/10.6060/tcct.20165909.13y.
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The mechanical and tribo-technical parameters of composite materials of mixtures on the bases of super- molecular polyethylene (SMPE) at conditions of dry friction and abrasive wear were studied for comparative estimation of solid- grease properties of nano and micro fibers of carbon. It was shown that wear resistance of polymer compositions of SMPE+0.5 weight% the percent of C(nano) increases by a factor 6.6 and for SMPE+5 weight% the percent of C(micro) increases by a factor 2.5 at conditions of dry friction of slip. At conditions of abrasive wear the resistance of composites mentioned above increases by a factor about 2 for both types of fillers. The role of nano and micro fibers of carbon is discussed as solid grease in tribo- conjugated polymer compositions based on SMPE for application at various conditions of operation.
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Goloshchapov, Dmitry, Nikita Buylov, Anna Emelyanova, Ivan Ippolitov, Yuri Ippolitov, Vladimir Kashkarov, Yuri Khudyakov, Kirill Nikitkov i Pavel Seredin. "Raman and XANES Spectroscopic Study of the Influence of Coordination Atomic and Molecular Environments in Biomimetic Composite Materials Integrated with Dental Tissue". Nanomaterials 11, nr 11 (16.11.2021): 3099. http://dx.doi.org/10.3390/nano11113099.
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In this work, for the first time, the influence of the coordination environment as well as Ca and P atomic states on biomimetic composites integrated with dental tissue was investigated. Bioinspired dental composites were synthesised based on nanocrystalline calcium carbonate-substituted hydroxyapatite Ca4ICa6IIPO46−xCO3x+yOH2−y (nano-cHAp) obtained from a biogenic source and a set of polar amino acids that modelled the organic matrix. Biomimetic composites, as well as natural dental tissue samples, were investigated using Raman spectromicroscopy and synchrotron X-ray absorption near edge structure (XANES) spectroscopy. Molecular structure and energy structure studies revealed several important features related to the different calcium atomic environments. It was shown that biomimetic composites created in order to reproduce the physicochemical properties of dental tissue provide good imitation of molecular and electron energetic properties, including the carbonate anion CO32− and the atomic Ca/P ratio in nanocrystals. The features of the molecular structure of biomimetic composites are inherited from the nano-cHAp (to a greater extent) and the amino acid cocktail used for their creation, and are caused by the ratio between the mineral and organic components, which is similar to the composition of natural enamel and dentine. In this case, violation of the nano-cHAp stoichiometry, which is the mineral basis of the natural and bioinspired composites, as well as the inclusion of different molecular groups in the nano-cHAp lattice, do not affect the coordination environment of phosphorus atoms. The differences observed in the molecular and electron energetic structures of the natural enamel and dentine and the imitation of their properties by biomimetic materials are caused by rearrangement in the local environment of the calcium atoms in the HAp crystal lattice. The surface of the nano-cHAp crystals in the natural enamel and dentine involved in the formation of bonds with the organic matrix is characterised by the coordination environment of the calcium atom, corresponding to its location in the CaI position—that is, bound through common oxygen atoms with PO4 tetrahedrons. At the same time, on the surface of nano-cHAp crystals in bioinspired dental materials, the calcium atom is characteristically located in the CaII position, bound to the hydroxyl OH group. The features detected in the atomic and molecular coordination environment in nano-cHAp play a fundamental role in recreating a biomimetic dental composite of the natural organomineral interaction in mineralised tissue and will help to find an optimal way to integrate the dental biocomposite with natural tissue.
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Rocha, Marisa Cristina Guimarães, Gisele Fonseca Moreira i Antonio Henrique Monteiro Fonseca Thomé da Silva. "Evaluation of the effect of processing conditions on the impact properties of polypropylene-nano-CaCO3 composites". Journal of Composite Materials 51, nr 24 (5.01.2017): 3365–72. http://dx.doi.org/10.1177/0021998316688338.
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Processing variables are known to have a decisive influence on the impact properties of polypopylene-nano-CaCO3 composites. Therefore, it becomes mandatory to evaluate the effect of extrusion conditions on composite impact resistance. In the present work, a response surface methodology was used to evaluate the effects of screw rotation speed, screw configuration, and nanoparticles content on the polypropylene impact properties. The concentration of the nano-CaCO3 particles, the screw rotation speed, and the interaction between these entrance factors were the processing variables of greater influence on the impact properties of nano-CaCO3/polypropylene composites. The increase of screw rotation speed led to a decrease in the impact resistance, while the increase of filler content promoted an increase of such property. However, the increase of nanoparticles content led to obtaining poor tensile properties. Therefore, the filler content has to be adjusted in order to improve the impact properties without significant loss of mechanical strength.
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Rostamiyan, Yasser, i Amir Ferasat. "High-speed impact and mechanical strength of ZrO2/polycarbonate nanocomposite". International Journal of Damage Mechanics 26, nr 7 (11.04.2016): 989–1002. http://dx.doi.org/10.1177/1056789516644312.
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This study empirically investigates the mechanical strength and high-speed impact resistance of polycarbonate matrix reinforced with different amounts of nano-ZrO2. In order to enhance the mechanical strength of polycarbonate, especially the impact resistance, the nanoparticles were added to polycarbonate matrix as filler with the ratios of 1, 2, 3 and 5% of the composite’s total weight. Transmission electron microscope was utilized for the observation of microscopic structure of the composites, and it revealed an exceptional homogeneous mixture of ZrO2 particles in the polycarbonate matrix. From the results of the tests, it was figured out that adding 1–3 wt% of nano-ZrO2 into polycarbonate remarkably increased the impact resistance of the composite. The results also showed that adding 1 and 2 wt% of nano-ZrO2 to polycarbonate had the most desirable effects on the enhancement of tensile, bending and buckling strength; however, the composites with 3 wt% of nano-ZrO2 had the greatest Izod impact and high-velocity impact resistance. Finally for the impact tests, it was revealed that adding large amounts of nano-ZrO2 (more than 3 wt%) would decrease the mechanical strength of ZrO2/polycarbonate nanocomposite specimens; thus, the fracture occurred, while less energy was absorbed compared with the neat polymer.
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Tahriri, Mohammadreza, Fathollah Moztarzadeh, Arash Tahriri, Hossein Eslami, Kimia Khoshroo, Hossein E. Jazayeri i Lobat Tayebi. "Evaluation of the in vitro biodegradation and biological behavior of poly(lactic-co-glycolic acid)/nano-fluorhydroxyapatite composite microsphere-sintered scaffold for bone tissue engineering". Journal of Bioactive and Compatible Polymers 33, nr 2 (24.07.2017): 146–59. http://dx.doi.org/10.1177/0883911517720814.
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The objective of this research was to study the degradation and biological characteristics of the three-dimensional porous composite scaffold made of poly(lactic- co-glycolic acid)/nano-fluorhydroxyapatite microsphere using sintering method for potential bone tissue engineering. Our previous experimental results demonstrated that poly(lactic- co-glycolic acid)/nano-fluorhydroxyapatite composite scaffold with a ratio of 4:1 sintered at 90ºC for 2 h has the greatest mechanical properties and a proper pore structure for bone repair applications. The weight loss percentage of both poly(lactic- co-glycolic acid)/nano-fluorhydroxyapatite and poly(lactic- co-glycolic acid) scaffolds demonstrated a monotonic trend with increasing degradation time, that is, the incorporation of nano-fluorhydroxyapatite into polymeric scaffold could lead to weight loss in comparison with that of pure poly(lactic- co-glycolic acid). The pH change for composite scaffolds showed that there was a slight decrease until 2 weeks after immersion in simulated body fluid, followed by a significant increase in the pH of simulated body fluid without a scaffold at the end of immersion time. The mechanical properties of composite scaffold were higher than that of poly(lactic- co-glycolic acid) scaffold at total time of incubation in simulated body fluid; however, it should be noted that the incorporation of nano-fluorhydroxyapatite into composite scaffold leads to decline in the relatively significant mechanical strength and modulus during hydrolytic degradation. In addition, MTT assay and alkaline phosphatase activity results defined that a general trend of increasing cell viability was seen for poly(lactic- co-glycolic acid)/nano-fluorhydroxyapatite scaffold sintered by time when compared to control group. Eventually, experimental results exhibited poly(lactic- co-glycolic acid)/nano-fluorhydroxyapatite microsphere-sintered scaffold is a promising scaffold for bone repair.
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Jabr, Noha Abdullah Bin, Wacim Nassouh Al-Saidi, Ibtessam Abdullah Bin Jabr i Roula Safouh Al-Bounni. "Effect of Polymerization Time and Shade on the Depth of Cure of Nano-Hybrid Resin Composites". European Dental Research and Biomaterials Journal 2, nr 01 (styczeń 2021): 28–33. http://dx.doi.org/10.1055/s-0041-1726169.
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Abstract Objective The effect of polymerization time and resin shade on the depth of cure (DOC) of two nano-hybrid resin composites (Filtek Z250 XT and IPS Empress Direct) was evaluated and compared. Materials and Methods Sixty specimens were prepared from two shades (A1 and A3) of the resin composites. The specimens were allocated into two groups that were further divided into three subgroups depending on the polymerization time (20, 40, and 60 sec; n = 5). After that, the DOC was evaluated by calculating the polymerized part of the specimen’s thickness to the nearest (0.01 mm) using a high-accuracy micrometer. Each specimen was measured three times, and the corresponding mean reading (in mm) was divided by two to obtain the DOC. The data were analyzed using SPSS software, version 20. Descriptive statistics followed by three-way analysis of variance was applied. Multiple comparisons were made using Scheffe post hoc tests (α = 0.05). Results Filtek Z250 XT-A1-60sec presented with the greatest DOC (7.42 ± 0.47 mm), and the lowest DOC was obtained with IPS Empress-A3-20sec (2.31 ± 0.21 mm). The mean DOC of Filtek Z250 XT and IPS Empress Direct resin composites were 6.18 mm and 3.59 mm, respectively. Statistically significant (p < 0.05) difference was observed between the resin composites. The interaction between independent factors, namely composites, resin shade, and polymerization time, revealed that interaction between them contributed significantly to the DOC (p ≤0.05). However, the interaction between resin shade and the polymerization time was insignificant (p = 0.148). Conclusion Filtek Z250 XT demonstrated greater DOC than IPS Empress Direct resin composite. An increase in polymerization time significantly enhanced the DOC of the resin composites irrespective of the resin shade. Regardless of the resin composite tested, DOC was lower for darker shades (A3).
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Sufiiarov, Vadim, Danil Erutin, Evgenii Borisov i Anatoly Popovich. "Selective Laser Melting of Inconel 718/TiC Composite: Effect of TiC Particle Size". Metals 12, nr 10 (15.10.2022): 1729. http://dx.doi.org/10.3390/met12101729.
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In this article, we present the results of a study of the effect of TiC particle size on the microstructure and properties of a composite material based on the heat-resistant nickel alloy Inconel 718. Composite materials with the addition of 1% mass of micron- or nano-sized TiC particles were successfully manufactured by selective laser melting. Hot isostatic pressing and heat treatment were applied to manufactured samples. Increasing hardness with the addition of TiC particles by about 20% without dependence on TiC size was determined. The addition of nano-sized TiC leads to a greater increase in strength characteristics at room temperature and elevated temperature of 700 °C in comparison with pure Inconel 718 and the addition of micron-sized TiC particles, but also leads to decreasing elongation.
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Natrayan, L., Raviteja Surakasi, M. S. Heaven Dani, Pravin P. Patil, T. Manikandan, K. Tamil Mannan i Muse Degefe Chewaka. "Influence of SiO2 Filler Addition on the Types I and II Shear Fracture Toughness of Hemp Fiber-Reinforced Epoxy Mixtures". Journal of Nanomaterials 2023 (6.02.2023): 1–7. http://dx.doi.org/10.1155/2023/5440142.
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Natural fiber composites are now more costly than traditional building materials. Currently, industries are moving from traditional materials to natural fiber composites, and the price of natural fiber should be reduced through greater utilization of industrial production. This work aims to determine how matrix alteration affects the interlaminar characteristics of a hemp fiber-reinforced epoxy composite containing nano silicon oxide particles. Interlaminar modulus of rupture in Types I and II is assessed using dual cantilevered beams and end-notched deformation testing samples. Mechanical mixing and sonication are used to blend nanoscale SiO2 (30 nm) into the resin at concentrations of 0, 0.2, 0.4, and 0.6 wt%. The composites were made using the compression molding method. The composites were tested according to the American Society for Testing and Materials standards after manufacturing. The findings show that adding nanoparticles enhances interlaminar toughness values. Interlaminar fracture toughness improved by 20.25% and 30.35% for 0.4 wt% SiO2, respectively. The fiber matrix interaction and failure causes are examined using scanning electron microscope images.
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Farahanian, Zeynab, Nafiseh Zamindar, Gulden Goksen, Nick Tucker, Saeed Paidari i Elham Khosravi. "Effects of Nano-Bentonite Polypropylene Nanocomposite Films and Modified Atmosphere Packaging on the Shelf Life of Fresh-Cut Iceberg Lettuce". Coatings 13, nr 2 (2.02.2023): 349. http://dx.doi.org/10.3390/coatings13020349.
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In this study, the shelf life of fresh-cut iceberg lettuce (Lactuca sativa L.) was evaluated. Lettuce samples were washed with disinfectant agents and sodium hypochlorite and then soaked in an ascorbic acid solution. Next, samples were stored in packaging films containing three levels (1% and 3% and 0% as a control film) of nano-bentonite particles (NBPs) as a filler in a modified atmosphere for 12 days at 4 °C. Various physicochemical parameters such as color, texture, pH, titratable acidity, dehydration, moisture, dry matter, chlorophyll content, microbial quality, and sensory properties were investigated. Results indicated that nano-packaging had a significant ability to maintain the sensory physicochemical properties of lettuce at the fifth (1% nano-composite film) and ninth (3% nano-composite film) days of storage when compared to the control films. The greatest growths of molds and yeasts were observed in the control films, which demonstrates the effectiveness of the application of bentonite nanoparticle fillers.
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Garcia, Rosilei A., Tatjana Stevanovic, Joëlle Berthier, Guy Njamen, Balázs Tolnai i Alexis Achim. "Cellulose, nanocellulose, and antimicrobial materials for the manufacture of disposable face masks: A review". BioResources 16, nr 2 (25.02.2021): 4321–53. http://dx.doi.org/10.15376/biores.16.2.garcia.
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Cellulose is among the most promising renewable and biodegradable materials that can help meet the challenge of replacing synthetic fibers currently used in disposable N95 respirators and medical face masks. Cellulose also offers key functionalities that can be valued in filtration applications using approaches such as nanofiltration, membrane technologies, and composite structures, either through the use of nanocellulose or the design of functional composite filters. This paper presents a review of the structures and compositions of N95 respirators and medical face masks, their properties, and regulatory standards. It also reviews the use of cellulose and nanocellulose materials for mask manufacturing, along with other (nano)materials and composites that can add antimicrobial functionality to the material. A discussion of the most recent technologies providing antimicrobial properties to protective masks (by the introduction of natural bioactive compounds, metal-containing materials, metal-organic frameworks, inorganic salts, synthetic polymers, and carbon-based 2D nanomaterials) is presented. This review demonstrates that cellulose can be a solution for producing biodegradable masks from local resources in response to the high demand due to the COVID-19 pandemic and for producing antimicrobial filters to provide greater protection to the wearer and the environment, reducing cross-contamination risks during use and handling, and environmental concerns regarding disposal after use.
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Li, Lingfang, Changling Fan, Weihua Zhang i Taotao Zeng. "Hydro-thermal synthesis of SnO2@hard-carbon ultrafine composites for anodic performances in lithium-ion batteries". Materials Express 10, nr 10 (31.10.2020): 1677–84. http://dx.doi.org/10.1166/mex.2020.1832.
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Preparation of nano-structured SnO2@HC composites is an effective strategy to develop advanced tin-based anode materials for Li-ion batteries. In this study, cellulose with three-dimensional multi-layer structure was chosen as hard carbon source. An ultrafine composite of SnO2 and hard carbon, SnO2@HC, was prepared by hydro-thermal method. X Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), X-ray Photoelectron Spectroscopy (XPS), N2 adsorption–desorption technique, and electrochemical characterization were used to illustrate the microstructure, surface composition, pore features, and electrochemical performance of this composite. Results showed that in-situ growth of 3–5 nm SnO2 dots anchored on hard carbon particles formed a stable structure with abundant micropores and mesopores, which showed its good rate and cycle performance. The capacity stabilized at about 300 mAh/g after 10 cycles, at the current density of 200 mA/g. For the composite with Sn4+ to C molar ratio of 0.2:1, the discharge capacity was greater than 600 mAh/g at the current density of 50 mA/g, and 160 mAh/g capacity was released at 2 A/g.
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Cao, Genghua, Lu Zhang, Datong Zhang, Yixiong Liu, Jixiang Gao, Weihua Li i Zhenxing Zheng. "Microstructure and Properties of Nano-Hydroxyapatite Reinforced WE43 Alloy Fabricated by Friction Stir Processing". Materials 12, nr 18 (16.09.2019): 2994. http://dx.doi.org/10.3390/ma12182994.
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This research mainly focuses on the successful fabrication of nano-hydroxyapatite (nHA) reinforced WE43 alloy by two-pass friction stir processing (FSP). Microstructure evolution, mechanical properties, and in vitro corrosion behavior of FSPed WE43/nHA composite and FSPed WE43 alloy were studied. The results show that nHA particles are effectively dispersed in the processing zone, and the well-dispersed nHA particles can enhance the grain refine effect of FSP. The average grain sizes of FSPed WE43 alloy and WE43/nHA composite are 5.7 and 3.3 μm, respectively. However, a slight deterioration in tensile strength and yield strength is observed on the WE43/nHA composite, compared to the FSPed WE43 alloy, which is attributed to the locally agglomerated nHA particles and the poor quality of interfacial bonding between nHA particles and matrix. The electrochemical test and in vitro immersion test results reveal that the corrosion resistance of the WE43 alloy is greatly improved after FSP. With the addition of nHA particles, the corrosion resistance of the WE43/nHA composite shows an even greater improvement.
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Talic, Nabeel F. "Failure Rates of Orthodontic Fixed Lingual Retainers bonded with Two Flowable Light-cured Adhesives: A Comparative Prospective Clinical Trial". Journal of Contemporary Dental Practice 17, nr 8 (2016): 630–34. http://dx.doi.org/10.5005/jp-journals-10024-1902.
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ABSTRACT Introduction This comparative prospective randomized clinical trial examined the in vivo failure rates of fixed mandibular and maxillary lingual retainers bonded with two light-cured flowable composites over 6 months. Materials and methods Consecutive patients were divided into two groups on a 1:1 basis. Two hundred fixed lingual retainers were included, and their failures were followed for 6 months. One group (n = 50) received retainers bonded with a nano-hybrid composite based on nano-optimized technology (Tetric-N-Flow, Ivoclar Vivadent). Another group (n = 50) received retainers bonded with a low viscosity (LV) composite (Transbond Supreme LV, 3M Unitek). Results There was no significant difference between the overall failure rates of mandibular retainers bonded with Transbond (8%) and those bonded with Tetric-N-Flow (18%). However, the odds ratio for failure using Tetric-N-flow was 2.52-fold greater than that of Transbond. The failure rate of maxillary retainers bonded with Transbond was higher (14%), but not significantly different, than that of maxillary retainers bonded with Tetric- N-flow (10%). There was no significant difference in the estimated mean survival times of the maxillary and mandibular retainers bonded with the two composites. Conclusion Both types of composites tested in the current study can be used to bond fixed maxillary and mandibular lingual retainers, with low failure rates. How to cite this article Talic NF. Failure Rates of Orthodontic Fixed Lingual Retainers bonded with Two Flowable Light-cured Adhesives: A Comparative Prospective Clinical Trial. J Contemp Dent Pract 2016;17(8):630-634.
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Zhou, Lin, i Yanchun Fu. "Flame-Retardant Wood Composites Based on Immobilizing with Chitosan/Sodium Phytate/Nano-TiO2-ZnO Coatings via Layer-by-Layer Self-Assembly". Coatings 10, nr 3 (22.03.2020): 296. http://dx.doi.org/10.3390/coatings10030296.
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Composite coatings of inorganic nanomaterials with polyelectrolytes are promising materials for wood modification. Endowing wood with flame retardancy behavior can not only broaden the range of applications of wood, but also improve the safety of wood products. In this work, chitosan/sodium phytate/TiO2-ZnO nanoparticle (CH/SP/nano-TiO2-ZnO) composite coatings were coated on wood surface through layer-by-layer self-assembly. The morphology and chemical composition of the modified wood samples were analyzed using scanning electron microscopy and energy dispersive spectrometry. The thermal degradation properties and flame retardancy of the samples treated with different assembly structures were observed by thermogravimetric analysis, limiting oxygen test, and combustion test. Due to the presence of an effective intumescent flame retardant system and a physical barrier, the CH/SP/nano-TiO2-ZnO coatings exhibited the best flame retardant performance and required only approximately six seconds for self-extinguishing. The coated samples had a limiting oxygen index of 8.4% greater than the original wood.
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Colombo, Marco, Claudio Poggio, Alessandro Lasagna, Marco Chiesa i Andrea Scribante. "Vickers Micro-Hardness of New Restorative CAD/CAM Dental Materials: Evaluation and Comparison after Exposure to Acidic Drink". Materials 12, nr 8 (16.04.2019): 1246. http://dx.doi.org/10.3390/ma12081246.
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CAD/CAM (computer-aided design/computer-aided manufacturing) for indirect restorative materials has been recently introduced in dentistry. The purpose of this study was to evaluate the change of the surface micro-hardness of different restorative CAD/CAM materials after exposure to a carbonated acidic drink (Coca-Cola, Coca-Cola Company, Milan, Italy). One hundred and eighty specimens of identical size (2 mm thickness) were obtained by sectioning each tested CAD/CAM block of four materials: a hybrid ceramic (CERASMART™, GC Corporation, Tokyo, Japan), a resin nano ceramic (Lava™ Ultimate, 3M, Monrovia, CA, USA), a nanohybrid composite (Grandio blocs, VOCO GmbH, Cuxhaven, Germany), and a zirconia-reinforced lithium silicate glass ceramic (VITA SUPRINITY® PC; VITA Zahnfabrik, Bad Sackingen, Germany). Forty-five specimens of each material were tested. Micro-hardness was measured at baseline, after 7 days and after 28 days. The data were analyzed. The micro-hardness of each material varied significantly after immersion in Coca-Cola. The nanohybrid composite had a high initial micro-hardness and the greatest percentage loss after acid exposure. The hybrid ceramic and the resin nano ceramic had similar percentage losses of micro-hardness values even if the second material had higher initial values. The zirconia-reinforced lithium silicate glass ceramic had the highest baseline values and the lowest percentage loss of micro-hardness. The different CAD/CAM materials presented different micro-hardness values before and after acid exposure.
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Tian, Tian, Bo Dang, Feng Ding, Fengkun Li, Kai Yang, Jianzhi Yuan, Dongbo Wei i Pingze Zhang. "Study on the ZrN/Ag2O Micro–Nano Gradient Composite Structure Constructed on Pure Ti for Biomaterials". Coatings 11, nr 6 (3.06.2021): 677. http://dx.doi.org/10.3390/coatings11060677.
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Titanium and titanium alloys have been extensively utilized in biomedical implants due to their excellent comprehensive mechanical properties and biocompatibility. In this study, a ZrN/Ag2O micro–nano gradient composite structure was prepared on the surface of pure Ti by multi-arc ion plating (MAIP) technique and metal vapor vacuum arc (MEVVA) ion implantation technology. This study indicated that a dramatic improvement in performance in the surface hardness (~1800 HV0.1) was attributed to the presence of the ceramic phase (ZrN) with high hardness included in composite structure. The relatively low wear rate of gradient composite structure confirmed its excellent performance in abrasion resistance and the abrasion mechanism of gradient composite structure was mainly abrasive wear. After the potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests, because of the synergy effect of ZrN micron coating and Ag2O nanoparticles, the ZrN/Ag2O gradient coatings indicated the highest free corrosion potential (Ecorr) and lowest corrosion current density (icorr) in Ringer’s solution, and the polarization resistances of multilayer coatings were greater than that of the substrate, exhibiting positive effects on retarding localized corrosion tendency. Additionally, the suitable dose of ZrN/Ag2O gradient composite coating can obtain antibacterial ability, which exerts no significant cytotoxicity and even excellent cytocompatibility over a longer service process. Furthermore, this study is conducive to design and develop for multifunctional coatings of implant materials.
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As, Albadah, i Khan Am. "An in Vitro Study Comparing Nano-Composite Microleakage with and without Hydroxyapatite-Reinforced Glass Ionomer Cement and Cention N as a Base Material in Class I Cavity". Pakistan Journal of Medical and Health Sciences 16, nr 5 (29.05.2022): 400–402. http://dx.doi.org/10.53350/pjmhs22165400.
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Aim: This study assessed microleakage in class one cavities in premolar teeth treated with Nano-composites using Cention N and Hydroxyapatite reinforced Glass ionomer cement as a base. Materials and Methods: In Sixty premolars, Class I cavities, one-fourth the intercuspal distance wide and 0.5-1mm deep were formed. Three groups were made. Group 1 received only Nano-Composites, Group 2, Nano-Composites with Cention N, and Group 3, Nano-Composites with Hydroxyapatite reinforced GIC was used as a base material. After 24 hours in distilled water, samples were undergone 5000 thermocycles at 5°C to 55°C. Samples were dried, and apical surfaces were sealed and saved for a 1mm wide zone around the restoration margins. Teeth were coloured with 2% Methylene blue. All the teeth were longitudinally sectioned and examined under a microscope Results: The least microleakage and internal gaps with GIC reinforced by Hydroxyapatite used as a base material (1.03± 0.832), followed by Nanocomposites. (2.08 ± 1.347). However, the greatest microleakage was observed with Cention N when used as a base (2.60 ± 0.928). A strong positive correlation was also observed between microleakage and internal gap formation. Conclusion: Cention N demonstrated the maximum microleakage as a base material, followed by Nanocomposite. GIC with Hydroxyapatite as a base material showed the least microleakage. Keywords: Cention N, GIC reinforced by Hydroxyapatite, Nanocomposite, base material, Microleakage
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Zhang, Zuoqun, Chaoshan Yang, Hua Cheng, Xiaohan Huang i Yuhao Zhu. "The Electromagnetic Wave Absorption Performance and Mechanical Properties of Cement-Based Composite Material Mixed with Functional Aggregates with High Fe2O3 and SiC". Revue des composites et des matériaux avancés 31, nr 4 (31.08.2021): 249–55. http://dx.doi.org/10.18280/rcma.310409.
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Now there’re many researches on the electromagnetic radiation protection function of the cement-based electromagnetic wave absorbing materials, such materials have been widely used in various types of buildings. This paper proposed an idea for preparing a cement-based composite material by mixing functional aggregates with high content of Fe2O3 and SiC, that is, adding Fe3O4 powder and nano-SiC of different contents in the clay, and then sintering at 1190℃; the prepared aggregates showed obvious magnetic loss and dielectric loss to electromagnetic waves, and the numerical tube pressure could reach 16.83MPa. The double-layer reflectivity test board made of functional aggregates showed excellent electromagnetic wave absorption performance, its reflection loss was less than -10dB in the frequency range of 8~18GHz (corresponding to energy absorption greater than 90% EM), and its maximum RL reached -12.13dB. In addition, the compressive strength of the cement-based composite material at the age of 28 days reached 50.1 MPa, which can meet the strength requirements of building materials.
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Bensalah, Fatma, Julien Pézard, Naoufel Haddour, Mohsen Erouel, François Buret i Kamel Khirouni. "Carbon Nano-Fiber/PDMS Composite Used as Corrosion-Resistant Coating for Copper Anodes in Microbial Fuel Cells". Nanomaterials 11, nr 11 (21.11.2021): 3144. http://dx.doi.org/10.3390/nano11113144.
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The development of high-performance anode materials is one of the greatest challenges for the practical implementation of Microbial Fuel Cell (MFC) technology. Copper (Cu) has a much higher electrical conductivity than carbon-based materials usually used as anodes in MFCs. However, it is an unsuitable anode material, in raw state, for MFC application due to its corrosion and its toxicity to microorganisms. In this paper, we report the development of a Cu anode material coated with a corrosion-resistant composite made of Polydimethylsiloxane (PDMS) doped with carbon nanofiber (CNF). The surface modification method was optimized for improving the interfacial electron transfer of Cu anodes for use in MFCs. Characterization of CNF-PDMS composites doped at different weight ratios demonstrated that the best electrical conductivity and electrochemical properties are obtained at 8% weight ratio of CNF/PDMS mixture. Electrochemical characterization showed that the corrosion rate of Cu electrode in acidified solution decreased from (17 ± 6) × 103 μm y−1 to 93 ± 23 μm y−1 after CNF-PDMS coating. The performance of Cu anodes coated with different layer thicknesses of CNF-PDMS (250 µm, 500 µm, and 1000 µm), was evaluated in MFC. The highest power density of 70 ± 8 mW m−2 obtained with 500 µm CNF-PDMS was about 8-times higher and more stable than that obtained through galvanic corrosion of unmodified Cu. Consequently, the followed process improves the performance of Cu anode for MFC applications.
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Miedzianowska, Justyna, Marcin Masłowski, Przemysław Rybiński i Krzysztof Strzelec. "Straw/Nano-Additive Hybrids as Functional Fillers for Natural Rubber Biocomposites". Materials 14, nr 2 (9.01.2021): 321. http://dx.doi.org/10.3390/ma14020321.
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Currently, up to 215 million metric tons of harvestable straw are available in Europe, 50% of the crops come from wheat, 25% from barley and 25% from maize. More than half of the production remains undeveloped. The overproduction of straw in the world means that the current methods of its management are insufficient. The article describes the production method and characterization of natural rubber biocomposites containing cereal straw powder modified with functional nano-additives in the form of carbon black, silica and halloysite nanotubes. The use of cereal straw in the elastomer matrix should contribute to obtaining a product with good mechanical properties while ensuring a low cost of the composite. In turn, the application of the mechanical modification process will allow the combination of specific properties of raw materials to obtain new, advanced elastomeric materials. As part of the work, hybrid fillers based on mechanically modified cereal straw were produced. The impact of hybrid fillers on mechanical, rheometric and damping properties was assessed. The flammability and susceptibility of the obtained biocomposites to aging processes were determined. The use of hybrid fillers based on mechanically modified straw allowed us to obtain a higher cross-linking density of vulcanizates (even up to 40% compared to the reference sample), and thus higher values of the rheometric moment during the vulcanization process of rubber mixtures (from approx. 10% (10 phr of filler) up to 50% (30 phr of filler) in relation to the unfilled system) and higher hardness of vulcanizates (by about 30–70%). The curing time of the blends was slightly longer, but the obtained composites were characterized by significantly higher tensile strength. The use of fillers in the elastomer matrix increased the modulus at 100, 200 and 300% and the elongation at break. Moreover, greater resistance of vulcanizates to the combustion process was confirmed.
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Miedzianowska, Justyna, Marcin Masłowski, Przemysław Rybiński i Krzysztof Strzelec. "Straw/Nano-Additive Hybrids as Functional Fillers for Natural Rubber Biocomposites". Materials 14, nr 2 (9.01.2021): 321. http://dx.doi.org/10.3390/ma14020321.
Pełny tekst źródłaStreszczenie:
Currently, up to 215 million metric tons of harvestable straw are available in Europe, 50% of the crops come from wheat, 25% from barley and 25% from maize. More than half of the production remains undeveloped. The overproduction of straw in the world means that the current methods of its management are insufficient. The article describes the production method and characterization of natural rubber biocomposites containing cereal straw powder modified with functional nano-additives in the form of carbon black, silica and halloysite nanotubes. The use of cereal straw in the elastomer matrix should contribute to obtaining a product with good mechanical properties while ensuring a low cost of the composite. In turn, the application of the mechanical modification process will allow the combination of specific properties of raw materials to obtain new, advanced elastomeric materials. As part of the work, hybrid fillers based on mechanically modified cereal straw were produced. The impact of hybrid fillers on mechanical, rheometric and damping properties was assessed. The flammability and susceptibility of the obtained biocomposites to aging processes were determined. The use of hybrid fillers based on mechanically modified straw allowed us to obtain a higher cross-linking density of vulcanizates (even up to 40% compared to the reference sample), and thus higher values of the rheometric moment during the vulcanization process of rubber mixtures (from approx. 10% (10 phr of filler) up to 50% (30 phr of filler) in relation to the unfilled system) and higher hardness of vulcanizates (by about 30–70%). The curing time of the blends was slightly longer, but the obtained composites were characterized by significantly higher tensile strength. The use of fillers in the elastomer matrix increased the modulus at 100, 200 and 300% and the elongation at break. Moreover, greater resistance of vulcanizates to the combustion process was confirmed.
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AlShaafi, MM, A. AlQussier, MQ AlQahtani i RB Price. "Effect of Mold Type and Diameter on the Depth of Cure of Three Resin-Based Composites". Operative Dentistry 43, nr 5 (1.09.2018): 520–29. http://dx.doi.org/10.2341/17-122-l.
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SUMMARY Objective: To evaluate the effects of different mold materials, their diameters, and light-curing units on the mechanical properties of three resin-based composites (RBC). Methods and Materials: A conventional nano-filled resin composite (Filtek Supreme Ultra, 3M Oral Care, St Paul, MN, USA) and two bulk-fill composites materials, Tetric Evoceram Bulk fill (Ivoclar Vivadent, Schaan, Liechtenstein) and Aura Bulk Fill (SDI, Bayswater, VIC, Australia), were tested. A total of 240 specimens were fabricated using metal or white semitransparent Delrin molds that were 4 or 10 mm in diameter. The RBCs were light cured for 40 seconds on the high-power setting of either a monowave (DeepCure-S, 3M Oral Care) or polywave (Bluephase G2, Ivoclar Vivadent) light-emitting diode (LED) curing unit. The depth of cure was determined using a scraping test, according to the 2009 ISO 4049 test method. Data were analyzed using multivariate analysis of variance followed by Tukey multiple comparison test (p<0.05). Results: In general, when used for 40 seconds, both LED curing lights achieved the same depth of cure (p=0.157). However, the mold material and its diameter had a significant effect on the depth of cure of all three RBCs (p<0.0001). Conclusion: Curing with either the polywave or monowave LED curing light resulted in the same depth of cure in the composites. The greatest depth of cure was always achieved using the 10-mm-diameter Delrin mold. Of the three RBCs tested, both Tetric Bulk Fill and Aura achieved a 4-mm depth of cure when tested in the 10-mm-diameter metal mold. Tetric Bulk Fill was the most transparent and had the greatest depth of cure, and the conventional composite had the least depth of cure. Very little violet (<420 nm) light penetrated through 6 mm of any of the RBCs.
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Cheng, Gang, Hong Chen, Kai Wang, Jinxing Gao, Xiao Li, Hui Dong i Shuyan Liu. "Biphasic Calcium Phosphate/Chitosan/Polyacrylonitrile/Polylactic Acid-Glycolic Acid (PLGA) Nanocomposite Stent for Repair and Osteogenesis of Oral Alveolar Bone Defect". Science of Advanced Materials 13, nr 7 (1.07.2021): 1324–34. http://dx.doi.org/10.1166/sam.2021.4039.
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ABSTRACTThe ability of sol-gel micro-nano biphasic calcium stent to repair oral alveolar bone defects was investigated in this study, and its osteogenesis performance was also analyzed. Biphasic calcium phosphate (BCP) was synthesized by wet method, which was combined with chitosan (CS), polyacrylonitrile (PAN), and polylactic acid-glycolic acid (PLGA). Then, the BCP/CS/PAN/PLGA nanocomposite stent was prepared by vacuum freeze-drying technology. The micro-nano composite stent was combined with the bone morphogenetic protein-2 (BMP-2) gene, so as to obtain the sol-gel micro-nano biphasic calcium BMP-2/BCP/CS/PAN/PLGA composite stent. Besides, the composite stent should be measured in terms of compressive strength, porosity, structure, and morphological features. The healthy female rhesus monkeys were taken as the research animals, and the iliac bone marrow was extracted by puncture. The mesenchymal stem cells (MSCs) were obtained by density gradient centrifugation, and their osteogenic differentiation ability was observed. The MSCs were cultured in vitro with BMP-2/BCP/CS/PAN/PLGA composite stent, methylthiazolyldiphenyl-tetrazolium bromide (MTT) was applied to detect cell adhesion and proliferation, and the alkaline phosphatase (ALP) activity was employed to analyze its osteogenic properties on stent materials. In addition, the expression of BMP-2 was detected by Western blot. The alveolar bone defect models were established and divided into group A (MSCs + BMP-2/BCP/CS/PAN/PLGA), group B (BMP-2/BCP/CS/PAN/PLGA), group C (BCP/CS/PAN/PLG), and group D (control group, reposition of gingival flap and suture) according to different implant materials. The changes of bone defect area in different groups were detected by gross examinations and X-ray, so that the new bone density was analyzed. The results showed that the BCP/CS/PAN/PLGA composite stent exhibited a porous structure combining multiple pores/small pores, with an average pore diameter (PD) of 400–500 µm, maximum compressive strength of 6.02 Mpa, and porosity of 86.82%. MSCs differentiated into osteoblasts under osteogenic induction conditioned medium, and the optical density (OD) of CS + MSCs/BMP-2/BCP/CS/PAN/PLGA cells was greater in contrast to that of MSCs/BMP-2/BCP/CS/PAN/PLGA cells on the 1st and 7th day of culture, showing a statistical difference (P < 0.05). The gross examination and X-ray of bone defect area in group A showed that its bone structure and density were very close to those of normal bone (all materials were absorbed, and newly formed bone cells were active); the CT value of alveolar bone in groups A, B, C, and D was 1,092.45± 15.87 g/cm3, 932.26± 16.75 g/cm3, 859.51 ±17.86 g/cm3, and 787.96± 16.54 g/cm3, respectively. There was no marked difference in CT values between group A and normal alveolar bone (P > 0.05), while the CT value of alveolar bone in group A was higher obviously than the value of groups C and D (P < 0.05). It indicated that the composite stent based on sol–gel micro-nano biphasic calcium BMP-2/BCP/CS/PAN/PLGA could promote the repair of oral alveolar bone defect and its osteogenesis, thereby providing a reference for the oral clinical treatment of periodontal bone defects.
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Lu, Zihan, Qasim Zia, Jinmin Meng, Ting Liu, Jun Song i Jiashen Li. "Hierarchical porous poly(l-lactic acid)/SiO2 nanoparticles fibrous membranes for oil/water separation". Journal of Materials Science 55, nr 34 (2.09.2020): 16096–110. http://dx.doi.org/10.1007/s10853-020-05115-2.
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Abstract A two-step strategy has been developed to introduce silica nanoparticles into highly porous poly(l-lactic acid) (PLLA) nanofibers. Silica nanoparticles (SiNPs) were firstly synthesized and then modified to be hydrophobic. After PLLA/SiNPs composite fibrous membranes were electrospun and collected, they were re-crystallized by acetone at room temperature for a few minutes. With the re-arrangement of PLLA chains, the nano-/micro-electrospun fibres were transformed from non-porous ones to be porous ones with high surface area. Consequently, SiNPs that were completely covered by PLLA before acetone treatment showed up at the fibre surface. Higher PLLA crystallization also enhanced the Young’s modulus and tensile strength (420 and 8.47 MPa) of the composite membrane. However, incorporation of SiNPs into porous PLLA membranes reduced their modulus and tensile strength (280.66 and 5.92 MPa), but an increase in strain to fracture (80.82%) was observed. Scanning electron microscopy (SEM), focused ion beam SEM, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction were applied to confirm the presence of SiNP in PLLA fibres. The presence of SiNPs inside and outside fibres enhances the hydrophobicity of PLLA/SiNPs nano-fibrous membrane as the water contact angle is greater than 150°. The oil absorption of these porous composite membranes was also tested using four different oils, which can reach the highest absorption capacity when the weight ratio of PLLA and SiNPs is 1:1. The flux of prepared membranes was investigated, and results indicated that SiNPs-loaded membrane effectively enhanced the flux (5200 Lm−2 h−1).
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Al-Saud, Loulwa M., Lina M. Alolyet i Dhayah S. Alenezi. "The Effects of Selected Mouthwashes on the Surface Microhardness of a Single-shade Universal Resin Composite: In Vitro Study". Journal of Advanced Oral Research 13, nr 2 (18.10.2022): 234–44. http://dx.doi.org/10.1177/23202068221129020.
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Aim: To investigate the effects of selected alcohol-free mouthwashes with different formulations (zinc-hydroxyapatite, hydrogen peroxide, and sodium fluoride) on the surface microhardness of a single-shade universal resin composite. Materials and Methods: Forty disc-shaped specimens (8 × 2 mm) from the universal resin composite (Omnichroma®), and a nano-hybrid composite (Tetric® N-Ceram) were prepared. After polymerization, baseline surface microhardness values were recorded using Vickers microhardness tester. The samples from each material were randomly assigned to 4 groups ( n = 10) and immersed in 20 ml of the mouthwashes: Biorepair®, Listerine®, Colgate® Optic White, and distilled water (control). The samples were kept in the immersion solutions for 24 hours, and post-immersion microhardness values were recorded. Data were analyzed with one-way ANOVA and paired sample t-tests at p < .05. Results: Significant reduction in microhardness was observed in all resin composite groups after immersion in the mouthwashes compared to baseline values ( p < .0001). The highest microhardness reduction in Omnichroma® group was observed after immersion in Colgate® Optic White; and Tetric® N-Ceram group after immersion in Listerine® mouthwash. For both materials, the least reduction in microhardness was observed after immersion in Biorepair®. Microhardness values for Omnichroma were significantly higher than Tetric® N-Ceram ( p < .0001). However, Omnichroma exhibited a significantly greater reduction in microhardness after immersion in the tested mouthwashes. Conclusion: In vitro simulated use of the investigated mouthwashes negatively affected the surface microhardness of both tested resin composites. The observed effects were both mouthwash and material dependent.
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Zang, Jiawei, Chonggen Pan, Xu Li, Keyu Chen i Danting Chen. "Research on Salt Corrosion Resistance of Lithium-Based Protective Coating on Mortar Substrate". Materials 16, nr 9 (29.04.2023): 3463. http://dx.doi.org/10.3390/ma16093463.
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The present study concerns hydrophobic surface treatments with silane-based coating on concrete surfaces against external ionic transport. The nano-modification and organic–inorganic modification were carried out on it and applied to the mortar matrix and concrete matrix. Lithium-based protective coating (PC1, PC2), nano-modified coating (NC1, NC2) and organic–inorganic composite coating (OL1) were prepared. The salt erosion resistance of the mortar matrix and concrete matrix was tested, compared with the blank group and the market. The test results found that the organic–inorganic modified OL1 and LC1 coatings have the greatest influence on the chloride penetration resistance of the mortar matrix, in which the chloride penetration depth of 28 days is reduced by 73.03% and 63.83%, respectively, compared with the blank group. The rate of mass change of the blank group, PC1 and PC2 coatings, and NL1 and NL2 coatings were 0.17%, 0.08%, and 0.03%, respectively. The result demonstrated that the lithium-based coating could effectively delay the penetration rate of chloride ions and sulfates into the mortar, and the nano-modified properties could improve the salt resistance. The scanning electron microscopy (SEM) showed that coating treatment would promote the secondary hydration of cement-based materials, by reducing the content of Ca(OH)2 in hydration products of cement-based materials and producing C-S-H gel, which is conducive to strength enhancement and pore refinement. The nano-component would promote the reaction degree, while the organic–inorganic coating would have the respective advantages of the two components.
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Batool, Misbah, Hasan B. Albargi, Adnan Ahmad, Zahid Sarwar, Zubair Khaliq, Muhammad Bilal Qadir, Salman Noshear Arshad i in. "Nano-Silica Bubbled Structure Based Durable and Flexible Superhydrophobic Electrospun Nanofibrous Membrane for Extensive Functional Applications". Nanomaterials 13, nr 7 (23.03.2023): 1146. http://dx.doi.org/10.3390/nano13071146.
Pełny tekst źródłaStreszczenie:
Nanoscale surface roughness has conventionally been induced by using complicated approaches; however, the homogeneity of superhydrophobic surface and hazardous pollutants continue to have existing challenges that require a solution. As a prospective solution, a novel bubbled-structured silica nanoparticle (SiO2) decorated electrospun polyurethane (PU) nanofibrous membrane (SiO2@PU-NFs) was prepared through a synchronized electrospinning and electrospraying process. The SiO2@PU-NFs nanofibrous membrane exhibited a nanoscale hierarchical surface roughness, attributed to excellent superhydrophobicity. The SiO2@PU-NFs membrane had an optimized fiber diameter of 394 ± 105 nm and was fabricated with a 25 kV applied voltage, 18% PU concentration, 20 cm spinning distance, and 6% SiO2 nanoparticles. The resulting membrane exhibited a water contact angle of 155.23°. Moreover, the developed membrane attributed excellent mechanical properties (14.22 MPa tensile modulus, 134.5% elongation, and 57.12 kPa hydrostatic pressure). The composite nanofibrous membrane also offered good breathability characteristics (with an air permeability of 70.63 mm/s and a water vapor permeability of 4167 g/m2/day). In addition, the proposed composite nanofibrous membrane showed a significant water/oil separation efficiency of 99.98, 99.97, and 99.98% against the water/xylene, water/n-hexane, and water/toluene mixers. When exposed to severe mechanical stresses and chemicals, the composite nanofibrous membrane sustained its superhydrophobic quality (WCA greater than 155.23°) up to 50 abrasion, bending, and stretching cycles. Consequently, this composite structure could be a good alternative for various functional applications.
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G.V., Yashaswini Devi, Apoorva H. Nagendra, Sudheer P. Shenoy, Kaushik Chatterjee i Jayachandran Venkatesan. "Fucoidan-Incorporated Composite Scaffold Stimulates Osteogenic Differentiation of Mesenchymal Stem Cells for Bone Tissue Engineering". Marine Drugs 20, nr 10 (21.09.2022): 589. http://dx.doi.org/10.3390/md20100589.
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Globally, millions of bone graft procedures are being performed by clinicians annually to treat the rising prevalence of bone defects. Here, the study designed a fucoidan from Sargassum ilicifolium incorporated in an osteo-inductive scaffold comprising calcium crosslinked sodium alginate-nano hydroxyapatite-nano graphene oxide (Alg-HA-GO-F), which tends to serve as a bone graft substitute. The physiochemical characterization that includes FT-IR, XRD, and TGA confirms the structural integration between the materials. The SEM and AFM reveal highly suitable surface properties, such as porosity and nanoscale roughness. The incorporation of GO enhanced the mechanical strength of the Alg-HA-GO-F. The findings demonstrate the slower degradation and improved protein adsorption in the fucoidan-loaded scaffolds. The slow and sustained release of fucoidan in PBS for 120 h provides the developed system with an added advantage. The apatite formation ability of Alg-HA-GO-F in the SBF solution predicts the scaffold’s osteointegration and bone-bonding capability. In vitro studies using C3H10T1/2 revealed a 1.5X times greater cell proliferation in the fucoidan-loaded scaffold than in the control. Further, the results determined the augmented alkaline phosphatase and mineralization activity. The physical, structural, and enriching osteogenic potential results of Alg-HA-GO-F indicate that it can be a potential bone graft substitute for orthopedic applications.
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Li, Lin, Chengfu Zhang, Lina Tian, Zihang Wu, Dongqing Wang i Tifeng Jiao. "Preparation and Antibacterial Properties of a Composite Fiber Membrane Material Loaded with Cationic Antibacterial Agent by Electrospinning". Nanomaterials 13, nr 3 (1.02.2023): 583. http://dx.doi.org/10.3390/nano13030583.
Pełny tekst źródłaStreszczenie:
Microbial infections due to bacteria, viruses, and molds are a serious threat to both human life and the health of other organisms. To develop inexpensive, easy-to-prepare, efficient, and portable nano-antibacterial materials, as well as to explore the antibacterial prospects of cationic antibacterial agents, in this work, six different membrane materials were prepared by the electrostatic spinning method and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR). The materials were tested for antimicrobial properties using a modified AATCC100-200 test method. Under the most suitable spinning conditions, the doping amount of the cationic antimicrobial agent, CTAB, had the greatest influence on the antimicrobial performance. The antimicrobial performance of PCL/PEO/CS/CTAB0.4 was the highest among the prepared materials, with 83.7% effectiveness against S. aureus and 99.9% against E. coli. The antimicrobial performance was found to be stable. In our study, we determined the most suitable spinning ratio to prepare an inexpensive and efficient cationic antimicrobial agent. Biodegradable, high-antimicrobial-activity antimicrobial materials can be applied as films, and this new nanofiber material has shown great potential in wound dressings and as a mask material due to its remarkable antimicrobial efficiency.
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Ebrahimi, M., Naruporn Monmaturapoj, S. Suttapreyasri i P. Pripatnanont. "The Fabricated Collagen-Based Nano-Hydroxyapatite/β-Tricalcium Phosphate Scaffolds". Advanced Materials Research 506 (kwiecień 2012): 57–60. http://dx.doi.org/10.4028/www.scientific.net/amr.506.57.
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The biphasic calcium phosphate (BCP) concept was introduced to overcome disadvantages of single phase biomaterials. In this study, we prepared BCP from nanoHA and β-TCP that were synthesized via a solid state reaction. Three different ratios of pure BCP and collagen-based BCP scaffolds (%HA/%β-TCP; 30/70, 40/60 and 50/50) were produced using a polymeric sponge method. Physical and mechanical properties of all materials and scaffolds were investigated. XRD pattern proved the purity of each HA, β-TCP and BCP. SEM showed overall distribution of macropores (80-200 µm) with appropriate interconnected porosities. Total porosity of pure BCP (93% ± 2) was found to be higher than collagen-based BCP (85%± 3). It was observed that dimensional shrinkage of larger scaffold (39% ± 4) is lower than smaller one (42% ± 5) and scaffolds with higher HA (50%) ratio experienced greater shrinkage than those with higher β-TCP (70%) ratio (45% ±3 and 36% ±1 respectively). Mechanical properties of both groups tend to be very low and collagen coating had no influence on mechanical behavior. Further studies may improve the physical properties of these composite BCP.
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Anil Kumar, Yedluri, Ganesh Koyyada, Dasha Kumar Kulurumotlakatla, Jae Hong Kim, Md Moniruzzaman, Salem Alzahmi i Ihab M. Obaidat. "In Situ Grown Mesoporous Structure of Fe-Dopant@NiCoOX@NF Nanoneedles as an Efficient Supercapacitor Electrode Material". Nanomaterials 13, nr 2 (10.01.2023): 292. http://dx.doi.org/10.3390/nano13020292.
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In this study, we designed mixed metal oxides with doping compound nano-constructions as efficient electrode materials for supercapacitors (SCs). We successfully prepared the Fe-dopant with NiCoOx grown on nickel foam (Fe-dopant@NiCoOx@NF) through a simple hydrothermal route with annealing procedures. This method provides an easy route for the preparation of high activity SCs for energy storage. Obtained results revealed that the Fe dopant has successfully assisted NiCoOx lattices. The electrochemical properties were investigated in a three-electrode configuration. As a composite electrode for SC characteristics, the Fe-dopant@NiCoOx@NF exhibits notable electrochemical performances with very high specific capacitances of 1965 F g−1 at the current density of 0.5 A g−1, and even higher at 1296 F g−1 and 30 A g−1, respectively, which indicate eminent and greater potential for SCs. Moreover, the Fe-dopant@NiCoOx@NF nanoneedle composite obtains outstanding cycling performances of 95.9% retention over 4500 long cycles. The improved SC activities of Fe-dopant@NiCoOx@NF nanoneedles might be ascribed to the synergistic reactions of the ternary mixed metals, Fe-dopant, and the ordered nanosheets grown on NF. Thus, the Fe-dopant@NiCoOx@NF nanoneedle composite with unique properties could lead to promising SC performance.
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da Silva Brum, Igor, Lucio Frigo, Renan Lana Devita, Jorge Luís da Silva Pires, Victor Hugo Vieira de Oliveira, Ana Lucia Rosa Nascimento i Jorge José de Carvalho. "Histomorphometric, Immunohistochemical, Ultrastructural Characterization of a Nano-Hydroxyapatite/Beta-Tricalcium Phosphate Composite and a Bone Xenograft in Sub-Critical Size Bone Defect in Rat Calvaria". Materials 13, nr 20 (15.10.2020): 4598. http://dx.doi.org/10.3390/ma13204598.
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Nowadays, we can observe a worldwide trend towards the development of synthetic biomaterials. Several studies have been conducted to better understand the cellular mechanisms involved in the processes of inflammation and bone healing related to living tissues. The aim of this study was to evaluate tissue behaviors of two different types of biomaterials: synthetic nano-hydroxyapatite/beta-tricalcium phosphate composite and bone xenograft in sub-critical bone defects in rat calvaria. Twenty-four rats underwent experimental surgery in which two 3 mm defects in each cavity were tested. Rats were divided into two groups: Group 1 used xenogen hydroxyapatite (Bio Oss™); Group 2 used synthetic nano-hydroxyapatite/beta-tricalcium phosphate (Blue Bone™). Sixty days after surgery, calvaria bone defects were filled with biomaterial, animals were euthanized, and tissues were stained with Masson’s trichrome and periodic acid–Schiff (PAS) techniques, immune-labeled with anti-TNF-α and anti-MMP-9, and electron microscopy analyses were also performed. Histomorphometric analysis indicated a greater presence of protein matrix in Group 2, in addition to higher levels of TNF-α and MMP-9. Ultrastructural analysis showed that biomaterial fibroblasts were associated with the tissue regeneration stage. Paired statistical data indicated that Blue Bone™ can improve bone formation/remodeling when compared to biomaterials of xenogenous origin.
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Josipovic, Renata, Irena Kuzmanovic-Radman, Ognjenka Jankovic, Aleksandra Djeri i Natasa Knezevic. "Marginal seal of direct composite veneers". Serbian Dental Journal 61, nr 4 (2014): 183–89. http://dx.doi.org/10.2298/sgs1404183j.
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Introduction. Advance in new nano-composite materials and adhesive systems has provided stronger bond with hard dental tissue as well as possibility for minimal cavity preparation. The aim of this study was to evaluate, using dye method, marginal seal of direct composite veneers placed on intact and abraded anterior teeth and polymerized with classical and soft start light curing technique. Material and Methods. The study was conducted on 40 extracted human anterior teeth. They were extracted for periodontal reasons and divided into two groups: intact teeth (20) and abraded teeth (20). 10 teeth in each group were polymerized with classical and soft start technique. Dye penetration was measured using stereo loupes with micrometer scale and six times magnification. Results. Linear dye penetration on the gingival wall when direct composite veneers were placed in intact teeth and polymerized with classical technique was 2.50 ?m, while on the incisal wall it was 0.5 ?m. Linear dye penetration on the gingival wall in intact teeth polymerized with soft start technique was 2.25 ?m, while on the incisal wall it was 2.0 ?m. Average dye penetration of direct composite veneers in abraded teeth polymerized with classical technique on the gingival wall was 3.0 ?m while on the incisal wall it was 1.25 ?m. Linear dye penetration in abraded teeth polymerized with soft start technique was greater on the gingival wall (3.50 ?m) than on the incisal wall (3.25 ?m). Conclusion. Smaller microcrack was observed on the incisal wall than on the gingival wall in all teeth regardless of the technique of polymerization used. The least dye penetration was observed in the group of intact teeth polymerized with classical technique of polymerization.