Chemical doping is an effective method to intrinsically modify the chemical and electronic property of graphene. We propose a novel approach to synthesize the nitrogen-doped graphene via thermal annealing graphene wit...Chemical doping is an effective method to intrinsically modify the chemical and electronic property of graphene. We propose a novel approach to synthesize the nitrogen-doped graphene via thermal annealing graphene with urea, in which the nitrogen source can be controllably released from the urea by varying the annealed temperature and time. The doped N content and the configuration N as well as the thermal stabilities are also evaluated with X-ray photoelectron spectroscopy and Raman spectra. Electrical measurements indi- cate that the conductivity of doped graphene can be well regulated with the N content. The method is expected to produce large scale and controllable N-doped graphene sheets for a variety of potential applications.展开更多
Stable sub 500 nm bovine serum albumin (BSA) microsphere suspensions were produced by controlled addition of acetone and ethanol to an aqueous solution of BSA, followed by stabilization process of the formed microsphe...Stable sub 500 nm bovine serum albumin (BSA) microsphere suspensions were produced by controlled addition of acetone and ethanol to an aqueous solution of BSA, followed by stabilization process of the formed microspheres at an elevated temperature. Microspheres produced by this acetone ethanol heat denaturation method were stabilized at relatively low temperatures (70～75℃) over a short period of time (20 min). The acetone ethanol heat denaturation method, in comparison with the traditional oil/ water technique for preparation of albumin microspheres, which requires high temperature (over 100℃) and longer heating time (more than 30 min) for stabilization, offers a number of advantages. This report describes the influence of process conditions, such as ratios of acetone to ethanol to BSA aqueous solution, heating time and heating temperature, on microsphere formation and their stability. A loading efficiency of 40% rose bengal was achieved. Rose bengal release rates from these microspheres in phosphate buffered saline medium at 37 ℃ were dependent on microsphere stabilities and 25% to 60% of initial loading drug were released in 15 days.展开更多
文摘Chemical doping is an effective method to intrinsically modify the chemical and electronic property of graphene. We propose a novel approach to synthesize the nitrogen-doped graphene via thermal annealing graphene with urea, in which the nitrogen source can be controllably released from the urea by varying the annealed temperature and time. The doped N content and the configuration N as well as the thermal stabilities are also evaluated with X-ray photoelectron spectroscopy and Raman spectra. Electrical measurements indi- cate that the conductivity of doped graphene can be well regulated with the N content. The method is expected to produce large scale and controllable N-doped graphene sheets for a variety of potential applications.
文摘Stable sub 500 nm bovine serum albumin (BSA) microsphere suspensions were produced by controlled addition of acetone and ethanol to an aqueous solution of BSA, followed by stabilization process of the formed microspheres at an elevated temperature. Microspheres produced by this acetone ethanol heat denaturation method were stabilized at relatively low temperatures (70～75℃) over a short period of time (20 min). The acetone ethanol heat denaturation method, in comparison with the traditional oil/ water technique for preparation of albumin microspheres, which requires high temperature (over 100℃) and longer heating time (more than 30 min) for stabilization, offers a number of advantages. This report describes the influence of process conditions, such as ratios of acetone to ethanol to BSA aqueous solution, heating time and heating temperature, on microsphere formation and their stability. A loading efficiency of 40% rose bengal was achieved. Rose bengal release rates from these microspheres in phosphate buffered saline medium at 37 ℃ were dependent on microsphere stabilities and 25% to 60% of initial loading drug were released in 15 days.
