Zein, an alcohol-soluble protein in corn, can self-assemble into spherical nanoparticles, which makes it an ideal carrier material for the encapsulation of hydrophobic bioactive molecules. However, zein nanoparticles easily aggregate in water and are sensitive to enzymatic degradation in the digestive system. A strategy to overcome their limitations is the incorporation of polysaccharides as a second polymer layer that provides stability to zein nanoparticles. This review introduces the characteristics of zein as they relate to understanding the formation of zein/polysaccharide nanoparticles. Particular attention is paid to the preparation methods for the zein/polysaccharide nanoparticles, as well as to the morphological observation methods and detection mechanism. Moreover, the properties and applications of zein/polysaccharide nanoparticles are highlighted.
The amount of leakage is the only direct indicator of the sealing performance of a Proton Exchange Membrane Fuel Cell (PEMFC). In this work, a predictive model is developed to quantitatively evaluate the variation of leakage for a PEMFC under temperature cycling conditions. The method first uses the Lattice-Boltzmann Method (LBM) to simulate the gas flow within the contact interfacial gap at various heights. Then the Finite Element Method is used to analyze the local and macroscale contact state of the sealing interface and to clarify the effect of contact stresses on the interfacial gap height. Finally, the generalized Maxwell model, which considers time-temperature transfer and stiffness growth, is used to calculate the interfacial contact stresses under temperature cycling. The validity of the model was verified by comparison with experimental data from the available literature. Further analysis showed that reduced start-up temperature exacerbated the stress relaxation effect and decreased the service life of the seal material. When the start-up temperature is reduced from 25°C to -20°C, the model predicts that the service life of the PEMFC will be reduced by 100 temperature cycles or more. The leakage variation in a cycle was also discussed, and it was found that the leakage fluctuation became more and more significant as the number of cycles increased, weakening system reliability.
Background: The purpose of the present study is to investigate the therapeutic effect of fasciotomy through multiple small skin incisions for the treatment of early osteofascial compartment syndrome in children. Methods: From January 2009 to May 2017, 56 pediatric patients with early osteofascial compartment syndrome in their limbs were admitted into our department and treated with multiple small skin incisions for decompression at the early stage. The skin incisions, function, and sensation of the limbs were followed up. Results: The osteofascial compartment syndrome was diagnosed at 7.4 ± 2.1 h after injury, and then fasciotomy was performed at 1.4 ± 0.4 h later. The average procedure time of fasciotomy was 12.7 ± 4.8 min. No postoperative incision infections or neurovascular injuries were observed in all the patients. The incisions completely healed in 7-10 days with an average healing time of 8 days without secondary suture. The patients were followed up for an average of 5.1 years. No Volkmann's contractures in the injured limbs were found. The appearance, electromyography, and nerve conduction velocity of the affected limbs were not significantly different from that of the contralateral limbs. All the patients were free of symptoms and were fully recovered of sensation and function, being an "excellent" outcome at the latest follow-up. Conclusion: Fasciotomy through multiple small skin incisions, which can be useful to decompress the compartment pressure with fewer complications, is a simple and effective strategy for the treatment of early osteofascial compartment syndrome in children.
This study aims to optimize the medium for xylanase activity by a newly isolated strain of Rhizopus stolonifer JS-1008 (R. stolonifer JS-1008) under solid-state fermentation (SSF) on corncob. Four quantitative variables impacting the enzyme activity were selected through onefactor-at-a-time design. They were nitrogen source, initial moisture content (IMC), inorganic salt, and surface active agent. In addition, the interaction among these factors was further investigated by response surface methodology (RSM). Statistical analysis revealed that among these factors, IMC and urea significantly affected the xylanase activity. Our data indicate that the optimal medium contains (g/g dry corncob): urea, 0.15; ZnSO 4 , 0.022; Tween-80, 0.08; IMC, 3. Under the optimal condition, the xylanase activity reached its maximum, 13.90 U/g dry substrate (DS), on the 10 th day of fermentation. This work provides a new potential strain to synthesize xylanase for biofuel production.
Studies have been made of the removal of minor amounts of H 2 S from natural gas by activated carbon. The surface alkalinity of the carbon had a considerable effect on the H 2 S capacity, although this was not permanent. Thus, when the carbon surface became neutral, the H 2 S content remained constant after the initial cycles of the purification/regeneration operation. The presence of water in natural gas was found to be critical for the use of activated carbon as a means of sweetening natural gas. However, although it enhanced the H 2 S capacity of the carbon, it made regeneration of the latter very difficult.
Abstract:The electric spark induced ignition mechanism for explosives needs further study. The ignition of powdery and bulky TATB by electrostatic discharge (ESD) was investigated. Up to 200 kV ultra-high voltage ESD was applied to powdery and bulky explosives of two TATB-based polymer-bonded explosives (named PBX-1 and PBX-2). The results showed that the spark sensitivities of powdery and bulky explosives are extremely different for the same formulation. The 50% ignition voltages of powdery PBX-1 and PBX-2 were 10.8 kV and 8.5 kV, respectively, while the values for the bulky samples (tablets) were not less than 200 kV. Both heat and the electric field can be transmitted into the powdery samples, on the other hand only the electric field can be transmitted into the bulk samples. The electric field has a smaller contribution while the heat has a larger contribution to the ignition during an ESD, i.e., the thermal effect plays a main role in the ignition process. Our experimental results are in good agreement with recent results calculated by density functional theory.
2009) Preparation of vertical alignment layers by blending polyimide precursors with and without side chains, Liquid Crystals, 36:2, 173-178, A series of polyimides (PIs) were prepared from the precursors, blends of a poly(amic acid) and a side-chain poly(amic acid), based on a diamine 4¢-(tert-butyldimethylsiloxy)biphenyl-4-yl 3,5-diaminobenzoate (DPA). The blended polyimide (bl-PI) films were relatively tough. The surface properties of the bl-PI films were characterised by surface energy measurement, X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance infrared spectroscopy (ATR-IR). The results showed that the non-polar side chains were highly enriched on the surface and 90 pretilt angles of liquid crystal molecules were generated regardless of side chain content. For comparison, the copolyimides (co-PI) with different DPA contents were synthesised. It was found that the enrichment of the side chain on the surface increased with increasing DPA content and the pretilt angles of liquid crystal molecules rose from 3 to above 20 when DPA content increased from 10% to 30%. For the polyimides based on a diamine without a non-polar end group, 4¢-biphenyl-4-yl 3,5-diaminobenzoate (DABBE), both bl-PIs and co-PIs could only generate the same low pretilt angles. In conclusion, by blending poly(amic acids) based on DPA, tough vertical alignment layers could be prepared.
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