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This work aims to investigate the effects of deep eutectic solvents (DES) on the chemical and physical structure of cellulose. Choline chloride-oxalic acid and choline chloride-oxalic acid-glycerol were selected as solvents and cotton fibers was sued as raw materials to explore the difference between cotton fibers treated separately with two different DES. According to yield analysis, ternary solvents alleviated the degradation of cellulose when comparing to binary solvents, resulting in over 90 % of cellulose being obtained. Particularly, there is an esterification reaction of cellulose during treatment with the DES system, which also affects the performance of the subsequent products. Through the simple use of mechanical foaming with polyvinyl alcohol and the palm wax impregnation process, foams with a water contact angle greater than 140° and excellent mechanical properties can be obtained. The resultant foam material has 5 % linear elastic area, and prominent compressive strength providing potential use in the packaging industry in the replacement of plastic.

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In this work, we engineered a corn-straw-based bio-foam material under the inspiration of the intrinsic morphology of the corn stem. The explosion pretreatment was applied to obtain a fibrillated cellulose starting material rich in lignin. The in situ esterification of cellulose was adopted to improve the cross-linking network of the as-developed foam bio-material. The esterification of lignin was observed in the same procedure, which provides a better cross-linking interaction. The esterified corn-straw-derived bio-foam material showed excellent elastic resilience performance with an elastic recovery ratio of 83% and an elastic modulus of 20 kPa. Meanwhile, with surface modification by hexachlorocyclotriphosphazene-functionalized lignin as the flame retardant (Lig-HCCP), the as-obtained bio-foam material demonstrated quite a good flame retardancy (with 27.3% of the LOI), as well as a heat insulation property. The corn-straw-derived bio-foam material is prospected to be a potential substitution packaging material for widely used petroleum-derived products. This work provides a new value-added application of the abundant agricultural straw biomass resources.

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The backfill material for the underground pipe wall of Yellow River embankment was developed to avoid the high settlement and environmental damage caused by high filling and excavation. The interrelation between microstructure and compressive strength of the self-compacting foam backfill material with different water-binder ratios and density grades was investigated. The results indicated that the average pores size of the foam backfill material increased with increasing the water-binder ratio. Moreover, the compressive strength of the foam backfill material first increased and then decreased with continuously increasing the water-binder ratio. Based on the observation and the analysis of the computed tomography (CT) image, it can be found that the pore size of the foam backfill material decreased with the increment of the density grade. The overall findings demonstrated that the pore size and volume played an important role in affecting the performance of the foam backfill material used for the construction of the underground pipe wall of Yellow River embankment.

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In order to further increase the stability of the cannula behind the ribs and to facilitate cannula exteriorization in growing pigs, the present study aimed to evaluate whether elongation of the cannula flange could increase the stability of the cannula behind the ribs and to develop a tool to improve the exteriorization of the cannula through the ribs. Moreover, it was assessed whether a special skin protection paste and soft polyurethane foam material used in daily skin care could prevent erythema around the fistula. The feasibility of both, the modified simple T-cannula and daily skin care procedure, was evaluated in a digestibility experiment. Simple T-cannulae were made of high-molecular-weight polyethylene and inserted into the distal ileum of eight growing pigs (average body weight at surgery 30 kg). Modifications in the cannula design included a longer flange (11 cm) that was narrowed from the center to the ends and a bending of the flange to adapt it to the curve of the costal arch. In order to reduce the damage to the thread on the outer cannula barrel during surgery, a special surgical plug in conjunction with a screw thread on the inside of the barrel was developed. With respect to the daily cleaning of the fistula, a special skin protection paste was applied on the skin around the fistula to create a waterproof film that entirely sealed the skin. Additionally, foam material was inserted between the retaining ring and the skin to absorb the leaking digesta. Monitoring of the pigs throughout the trial showed that modifications in cannula design proved to be useful as they facilitated exteriorization of the cannula through the ribs and stability of the cannula behind the ribs. Moreover, the use of the skin protection paste and foam material during postsurgical treatment of growing pigs effectively prevented skin irritation around the flank area.

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Objective To explore the formation process of vacuum pressure differential of micro power negative pressure technology to facilitate its clinical application.MethodsThe formation of negative pressure differential and changes of negative pressure values in enclosure space were studied which was formed by liquid aspiration after the compressive polyvinyl alcohol foam material was enclosed.Micro power negative pressure technology was applied to the treatment of the right ear necrosis patient after focal cleaning,and the efficacy was observed.Results Medical adhesive film was raised gradually during the expansion of polyvinyl alcohol foam due to liquid aspiration,and then the enclosure space extended increasingly to form local vacuum negative pressure.The range of maximal negative pressure was between-110 and-200 Pa,and the mean maximal negative pressure value was-132.7 Pa.Micro power negative pressure technology behaved well in healing the wound.Conclusion Micro power negative pressure technology gains advantages in reliability and easy operation over other technologies and products,and may be a new choice for healing of refractory wounds.