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941.
Maria Giretova Lubomir Medvecky Radoslava Stulajterova Tibor Sopcak Jaroslav Briancin Monika Tatarkova 《Journal of materials science. Materials in medicine》2016,27(12):181
Polyhydroxybutyrate/chitosan/calcium phosphate composites are interesting biomaterials for utilization in regenerative medicine and they may by applied in reconstruction of deeper subchondral defects. Insufficient informations were found in recent papers about the influence of lysozyme degradation of chitosan in calcium phosphate/chitosan based composites on in vitro cytotoxicity and proliferation activity of osteoblasts. The effect of enzymatic chitosan degradation on osteoblasts proliferation was studied on composite films in which the porosity of origin 3D scaffolds was eliminated and the surface texture was modified. The significantly enhanced proliferation activity with faster population growth of osteoblasts were found on enzymatically degraded biopolymer composite films with α-tricalcium phosphate and nanohydroxyapatite. No cytotoxicity of composite films prepared from lysozyme degraded scaffolds containing a large fraction of low molecular weight chitosans (LMWC), was revealed after 10 days of cultivation. Contrary to above in the higher cytotoxicity origin untreated nanohydroxyapatite films and porous composite scaffolds. The results showed that the synergistic effect of surface distribution, morphology of nanohydroxyapatite particles, microtopography and the presence of LMWC due to chitosan degradation in composite films were responsible for compensation of the cytotoxicity of nanohydroxyapatite composite films or porous composite scaffolds. 相似文献
942.
Marialucia Gallorini Viviana di Giacomo Valentina Di Valerio Monica Rapino Domenico Bosco Andrea Travan Mara Di Giulio Roberta Di Pietro Sergio Paoletti Amelia Cataldi Silvia Sancilio 《Journal of materials science. Materials in medicine》2016,27(12):186
Silver-based products have been proven to be effective in retarding and preventing bacterial growth since ancient times. In the field of restorative dentistry, the use of silver ions/nanoparticles has been explored to counteract bacterial infections, as silver can destroy bacterial cell walls by reacting with membrane proteins. However, it is also cytotoxic towards eukaryotic cells, which are capable of internalizing nanoparticles. In this work, we investigated the biological effects of Chitlac-nAg, a colloidal system based on a modified chitosan (Chitlac), administered for 24–48?h to a co-culture of primary human gingival fibroblasts and Streptococcus mitis in the presence of saliva, developed to mimic the microenvironment of the oral cavity. We sought to determine its efficiency to combat oral hygiene-related diseases without affecting eukaryotic cells. Cytotoxicity, reactive oxygen species production, apoptosis induction, nanoparticles uptake, and lysosome and autophagosome metabolism were evaluated. In vitro results show that Chitlac-nAg does not exert cytotoxic effects on human gingival fibroblasts, which seem to survive through a homoeostasis mechanism involving autophagy. That suggests that the novel biomaterial Chitlac-nAg could be a promising tool in the field of dentistry. 相似文献
943.
944.
Surapong Chatpun Kittisak Sawanyawisuth Rungtiva Wansuksri Kuakoon Piyachomkwan 《Journal of materials science. Materials in medicine》2016,27(5):98
Plasma expanders (PEs) are administered fluids to replace blood volume when massive blood loss has occured. Maltodextrin from tapioca starch was selected as a study candidate to prepare a colloid PE due to an uncomplicated production process. The formulations of mixture between tapioca maltodextrin and 0.9 % sodium chloride solution were prepared and then characterized. This was to investigate the effects of a dextrose equivalent (DE) and the concentration on the physical properties. Storage stability of each formulation was also determined and compared with clinically used PE [6 % hydroxyethyl starch (HES), 130/0.4]. The effects on the circulatory system in hamsters with hemorrhagic shock and resuscitation using prepared PE were also investigated. The results showed that low DE value led to high retrogradation, turbidity and viscosity but low colloid osmotic pressure and poor solubility. Among the prepared solutions, tapioca maltodextrin with DE6 at 10 % w/v concentration had comparable properties with 6 % HES 130/0.4. Animals resuscitated with 10 % DE6 PE had improved mean arterial blood pressure similar to those resuscitated with 6 % HES 130/0.4. However, several parameters in animals resuscitated with 10 % DE6 PE were lower than those resuscitated with 6 % HES 130/0.4, i.e., heart rate, functional capillary density. Therefore, if using tapioca maltodextrin for PE, some properties have to be considered and efficiently optimized. 相似文献
945.
Wen Li Xiuxun Han Yun Zhao Shengrong Yang 《Journal of Materials Science: Materials in Electronics》2016,27(11):11188-11191
Molybdenum (Mo) is commonly used as the back contact material complying well with the formation of an ohmic contact for chalcogenide thin film solar cells. However, the easy formation of an over-thick MoSe2 layer between the Cu2ZnSn(S,Se)4 absorber and Mo back contact significantly deteriorates the device performance. To overcome the degradation, the effects of thermal treatment on Mo layers have been investigated in this paper. It was found that pre-annealing Mo back contacts is effective to control the growth of interfacial MoSe2 layer during selenization. Moreover, the thickness of MoSe2 layer could be conveniently tailored by simply varying the pre-annealing temperature. The work provides direct proof that the appearance of a thin MoO2 layer on the top of annealed Mo film indeed acts as a temporary barrier to block the over-selenization of Mo back contact. 相似文献
946.
Yuxia Kong Jigong Hao Dan Xu 《Journal of Materials Science: Materials in Electronics》2016,27(11):11256-11261
High aspect ratio patelike NaNbO3 particles with pure perovskite structure have been successfully synthesized by topochemical microcrystal conversion (TMC) from plate-like precursor particles of the layer-structured Bi2.5Na3.5Nb5O18. By changing the Bi2.5Na3.5Nb5O18/Na2CO3 ratio, large and thin NaNbO3 particles with a thickness of approximately 0.5 μm and a width of approximately 20 μm were obtained. The obtained NaNbO3 particles is quite suitable for fabricating textured (K0.5Na0.5)NbO3-based ceramics. Using the fine platelike NaNbO3 particles as templates, dense <001> -oriented (K0.5Na0.5)NbO3-0.5 mol %MnO2 ceramics with high texture quality (Lotgering factor F 001 = 87 %) and excellent piezoelectric properties were produced by templated grain growth. Compared with randomly oriented ceramics, textured samples show greatly enhanced properties. The room-temperature strain S, the piezoelectric coefficient d 33 * and d 33 reach up to 0.093 %, 233 pm/V and 195pC/N, respectively, which are all about 1.5 times larger than those of non-textured ceramics. 相似文献
947.
Xuexin Guo Jinbao Zhang Mucui Ni Li Liu Hongwei Lian Han Wang 《Journal of Materials Science: Materials in Electronics》2016,27(11):11262-11267
Hollow and porous α-Fe2O3 nanotubes were successfully synthesized by single nozzle electrospinning method followed by annealing treatment. The crystal structures and morphologies of the as-prepared materials were characterized by X-ray diffraction and scanning electron microscopy, respectively. The as-prepared materials were applied to construct gas sensor devices which gas sensing properties were further investigated. The obtained results revealed that porous α-Fe2O3 nanotube gas sensors exhibit a markedly enhanced gas sensing performance compared with hollow α-Fe2O3 nanotube gas sensors, which was about three times higher to 100 ppm acetone at 240 °C. Interestingly, hollow and porous α-Fe2O3 nanotube gas sensors both showed fast response–recovery time and good selectivity, but the porous ones possessed the shorter recovery time. The improved properties could be attributed to the unique morphology of porous nanotubes. Thus, further improvement of performance in metal-oxide-semiconductors materials could be realized by preparation the unique porous structures of nanotubes. Moreover, it is expected that porous metal-oxide-semiconductors nanotubes could be further design as promising candidates for gas sensing materials. 相似文献
948.
Linyu Cheng Hanming Ding Changhong Chen Ningning Wang 《Journal of Materials Science: Materials in Electronics》2016,27(4):3234-3239
TiO2 nanorod arrays (TiO2 NRAs) were synthesized through a hydrothermal method. Ag2S and Bi2S3 were then grown on the surface of TiO2 NRAs with successive ionic layer adsorption and reaction method. The pristine rutile TiO2 NRAs, Ag2S/TiO2, Bi2S3/TiO2, and Bi2S3/Ag2S/TiO2 electrodes were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet–visible absorption spectroscopy, and electrochemical analysis. According to photoelectrochemical (PEC) measurement, an enhanced short circuit current density was obtained for the co-sensitized TiO2 NRAs under simulated sunlight illumination, which was 10.7 times higher than that of the TiO2 NRAs. Appropriate potential positions of conduction band and valence band of Bi2S3 that match well those of rutile TiO2 NARs and Ag2S lead to the improved PEC performance. In addition, the PEC property of the co-sensitized TiO2 NRAs under visible light irradiation was also investigated and showed a dramatically enhanced photocurrent response. 相似文献
949.
Xiazhang Li Wei Zhu Yu Yin Xiaowang Lu Chao Yao Chaoying Ni 《Journal of Materials Science: Materials in Electronics》2016,27(5):4180-4185
La1?xAgxFeO3/halloysites nanotubes (HNTs) nanocomposite was synthesized by sol–gel method. It was characterized by X-ray diffraction, transmission electron microscope, Fourier transform infrared spectroscopy and UV–visible diffused reflectance spectroscopy measurements. The photo-activity of the La1?xAgxFeO3/HNTs nanocomposite was evaluated via degradation of methylene blue (MB) under visible-light irradiation. The results showed that the HNTs with unique pore structure favored the adsorption of organic molecules. Adequate Ag+ doping improved the absorption ability for visible light. The La0.95Ag0.05FeO3/HNTs demonstrated the best photocatalytic performance, which achieved as high as 99 % for MB degradation exposed 2 h irradiation. However,further increasing of Ag+ doping gradually reduced the photocatalytic activity. The nanocomposite catalyst showed outstanding recyclability after eight cycles which still remained up to 90 %. 相似文献
950.
Yih-Chien Chen Yen-Nien Wang Ruei-Yang Syu 《Journal of Materials Science: Materials in Electronics》2016,27(5):4259-4264
The microwave dielectric properties of Ba2MgWO6 ceramics were investigated with a view to the use of such ceramics in mobile communication. Ba2MgWO6 ceramics were prepared using the conventional solid-state method with various sintering temperatures. Dielectric constants (? r ) of 16.8–18.2 and unloaded quality factor (Q u × f) of 7000–118,200 GHz were obtained at sintering temperatures in the range 1450–1650 °C for 2 h. A maximum apparent density of 6.76 g/cm3 was obtained for Ba2MgWO6 ceramic, sintered at 1650 °C for 2 h. A dielectric constant (? r ) of 18.4, an unloaded quality factor (Q u × f) of 118,200 GHz, and a temperature coefficient of resonant frequency (τ f ) of ?34 ppm/°C were obtained when Ba2MgWO6 ceramics were sintered at 1650 °C for 2 h. 相似文献