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We describe an electrostatic droplet generation method to prepare a novel carboxymethyl chitosan-graphene oxide hybrid particles for delivery purpose. Under an adjustable electrostatic field, graphene oxide and carboxymethyl chitosan mixed solution was sprayed as uniform micro-droplets, which were solidified as particles in CaCl solution. Such hybrid particles are wished to have excellent stability in saline solution, and better delivery properties than pristine carboxymethyl chitosan particles. The effects of micro-droplets generation conditions on particles formation were systematically investigated. At conditions of 40 mg/ml of carboxymethyl chitosan, 2 mg/ml of graphene oxide, 3 ml/h of feed speed, electrostatic field parameters was 9 kV and 20 cm, uniformly sized carboxymethyl chitosan-graphene oxide particles in the diameter range of 250-300 μm was successfully prepared. In NaCl saline, these particles could maintain stable for at least a week, while pristine carboxymethyl chitosan particles quickly collapsed within an hour. The results of loading experiments showed that carboxymethyl chitosan-graphene oxide particles could effectively adsorb gatifloxacin, ofloxacin, bovine serum albumin, lysozyme, doxorubicin hydrochloride. And gatifloxacin was chosen as a model drug to study the exact effect of graphene oxide content on the loading and release properties. In 40:2 group, the highest loading capacity of 0.45 ± 0.19 mg/mg was achieved, and also a good sustained release was available. Above all, we believed that carboxymethyl chitosan-graphene oxide particles as a versatile carrier, has great potential in Medicine and Pharmacy.

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In view of the limited use of foam concrete for backfilling high-speed railway bridge approach and no publication considering the associated foundation treatment cost, this article presents a series of laboratory tests to study the mechanical properties of fiberglass-reinforced foam concrete with different contents of fiberglass, whereby the optimal values of target density and fiberglass content for fiberglass-reinforced foam concrete are obtained. A numerical model is developed to investigate the performance of bridge approach filled with fiberglass-reinforced foam concrete under different levels of foundation treatment in comparison with the control group with traditional backfills (combination of graded crushed stone and cement). Results indicate that the application of fiberglass-reinforced foam concrete to fill high-speed railway bridge approach can significantly improve the bridge approach performance (decreasing the horizontal displacement and ground surface settlement, respectively, by 58% and 21% than the control group) and cut down the foundation treatment cost by 19% concurrently.

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