Search

The micromorphology and functional properties of aerogels from rice, pea, potato or corn starch were characterized by a scanning electron microscope (SEM), an automatic surface area and pore size analyzer, an X-ray diffractometer, and a texture analyzer. The findings revealed that all the four starch aerogels had low density and high porosity. Under SEM observation, rice starch aerogel showed a lamellar structure, pea and potato starch aerogels showed a porous structure with uneven pore size distribution and thick pore walls in some zones, and corn starch aerogel presented a good three-dimensional network structure. The average pore sizes of the four starch aerogels were not much different, mainly distributed in the range of 5–13 nm, whereas there were differences in specific surface area, being smallest in pea starch aerogel (0.330 m2/g) and largest in corn starch aerogel (0.562 m2/g). The X-ray diffraction results showed that the crystallinity of these four starches declined after gelatinization and retrogradation, with corn starch experiencing the greatest decrease, from 30.71% to 8.13%. Compared with pea and potato starch aerogels, corn starch aerogel had higher solubility, water absorption rate, and Young’s modulus (6.233 MPa), and showed stronger deformation resistance, indicating excellent aerogel performance.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To meet the requirements of miniaturization, lightweight and precision of space optical instruments, an aperture driven by single-phase piezoelectric motor was designed. The whole structure of the apertures was designed to realize the integration of structure and function. Then, piezoelectric stators with high strength and power density were designed by using piezoelectric ceramics and carbon fiber composite materials. The dynamics characteristics of laminated piezoelectric stators were analyzed by COMSOL finite element software, and the modal frequency consistency was adjusted. The structure optimization and interference mode separation design of the moving rings of diaphragm were also completed. According to the design scheme, the prototype of piezoelectric apertures was manufactured. The mass is only 49 g, aperture range is in 0.5~35 mm.The experimental results show that the full opening and closing time of the apertures are as 89 ms and 92.4 ms respectively, and the minimum angular resolution is as 4x10-5 rad. This study simplifies the composition and control of the diaphragm, making it more compact in structures and smaller in weight while ensuring accuracy. [ABSTRACT FROM AUTHOR]

BACKGROUND: The aperture of bone tissue engineering scaffold is one of the important indexes to evaluate its biological performance, and seeking the best combination of aperture and mechanical properties has always been an urgent problem to be solved in bone tissue engineering. OBJECTIVE: To prepare three-dimensional scaffolds with different aperture gradients and to study their effects on the biological behavior of MC3T3-E1 cells. METHODS: The three-dimensional nano-hydroxyapatite scaffolds with uniform pore size were prepared by mixing wax spheres of specific diameter (300, 500, 800 μm) with hydroxyapatite as pore-forming agent using the modified particle leaching method, which were recorded as the D300, D500, and D800 scaffolds, respectively. The wax spheres of three diameters were piled up in order from small to large. The pore gradient nano-hydroxyapatite three-dimensional scaffold was prepared by the modified particle leaching method, which was recorded as the D-Gradient scaffold. The porosity of scaffolds of the four groups was measured. MC3T3-E1 cells were inoculated on scaffolds of the four groups. The cells cultured separately were used as the blank control group. Cell proliferation activity, alkaline phosphatase activity, cell adhesion, cytoskeleton rearrangement and the transcription level of osteogenic differentiation marker factors were detected. RESULTS AND CONCLUSION: (1) The porosity of scaffolds of the four groups was 60%-80%. (2) After 24 hours of inoculation, the scaffolds in each group could promote the proliferation of MC3T3-E1 cells. The proliferation index was: D-Gradient group > D500 group > D800 group > D300 group > blank control group. The scaffolds in the D300 group, D500 group, and D-Gradient group promoted the secretion of alkaline phosphatase in MC3T3-E1 cells. The amount of alkaline phosphatase secretion was: D300 group > D500 group > D-Gradient group > D800 group ≈ blank control group. The scaffolds in the D300 group, D500 group, and D-Gradient group promoted the expression of osteopontin and osteocalcin mRNA in MC3T3-E1 cells. The expression levels of the two genes from high to low were: D300 group > D500 group > D-Gradient group > D800 group ≈ blank control group. (3) Immunofluorescence staining after 48 hours of inoculation showed that compared with the blank control group, MC3T3-E1 cells on the four scaffolds showed better adhesion and locomotor activity. The fluorescence intensity of focal adhesion actin from high to low was: D-Gradient group > D500 group > D800C group > D300 group > blank control group. (4) It is concluded that the aperture gradient scaffolds promote the growth, proliferation, adhesion, and osteogenic differentiation of MC3T3-E1 cells. [ABSTRACT FROM AUTHOR]

The mode field diameter of optical fiber is very important for evaluating the performance of optical fiber. The far-field variable aperture method is commonly used to measure the mode field diameter in industry. At present, more and more apertures are needed in various measuring instruments based on the far-field variable aperture method, which results in long measurement time and low efficiency. In view of this problem, this study uses the optical power data measured by the OFM optical fiber measuring instrument, and applies the two-stages polynomial function fitting method to the processing of the mode field diameter. The experimental results show that the stability of the measurement results at 20 apertures is better than that of the original direct fitting method. On the premise of meeting the measurement accuracy, the original 20 apertures can be reduced to 10 apertures. The proposed method improves the measurement speed of the instrument and can meet the needs of optical fiber manufacturers for rapid testing in on-site quality control. [ABSTRACT FROM AUTHOR]

BACKGROUND: The microporous structure of a porous titanium alloy can not only provide sufficient space for the proliferation and migration of osteoblasts, but also promote the angiogenesis of mesenchymal stem cells, affect the expression of osteogenic genes and the differentiation of osteoblasts, which is an important factor for bone integration. OBJECTIVE: To analyze the osseointegration ability of three-dimensional printed porous titanium alloy scaffolds with different apertures in repairing rabbit femoral condyle defect. METHODS: Totally 40 hind legs of 20 New Zealand rabbits were randomly divided into group A, group B, group C, and group D. A 5 mm×5 mm bone defect model was established. Groups A, B, and C were implanted with porous titanium alloy scaffolds with a diameter of 200, 600, and 1 000 μm, while group D was not implanted. X-ray films were taken at 4 and 8 weeks after operation to observe whether there was displacement, prolapse and osteolysis, and osteonecrosis around the implants. At 8 weeks after operation, the trabecular thickness, trabecular number, trabecular volume, bone surface area density, and trabecular separation were detected by micro CT. The osseointegration was observed by histology. The experimental protocol was approved by the Animal Experiment Ethics Committee of Soochow University. RESULTS AND CONCLUSION: (1) X-ray films showed that the implants were in good position, without obvious displacement or falling off, and the bone around the materials was good, without osteolysis, osteonecrosis or other bad phenomena. (2) Micro-CT examination showed that bone tissue existed in the pores and around the implants in three groups. The number of trabeculae and bone surface area density in group B were significantly higher than those in the groups A and C (P < 0.05). The trabecular thickness of micropores in the group A was significantly higher than that in the groups B and C (P < 0.05). (3) Toluidine blue staining showed that the new bone tissue grew into almost all the surface micropores in group B, and some of the new bone extended into the deep pores of the experimental scaffold, closely combined with the porous structure, forming mechanical interlocking. Groups A and C had only a small amount of new bone tissues in surface micropores, and there was not new bone tissues in deep pores. The combination of new bone and implant was poor. (4) The results showed that the three-dimensional printed porous titanium alloy scaffold with 600 μm aperture was more conducive to new bone formation compared with 200 μm and 1 000 μm aperture. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Petroleum Machinery is the property of China Petroleum Machinery Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nonwovens made of ultrafine fibers has a big potential in filtration, insulation and absorbing medium market. The pore structure and fiber diameter of nonwovens have a dominant influence on the performance of the final products. In this study, nonwovens made of PA6/PE sea-island fiber was prepared by spunlace process. And after a treatment with xylene, nonwovens composed of ultrafine PA6 fibers was obtained. A comparison of the pore diameters, morphology, permeability and liquid behaviors of the nonwovens before and after the treatment was made. The results showed that after treated by xylene, the fiber's diameter was significantly dropped to 792 nm from 28 μm, and the pore diameter decreased by 85%. Moreover, its water-absorbing capacity, breaking strength and uniformity got better. [ABSTRACT FROM AUTHOR]