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Synthesis of hierarchically mesoporous silica with encapsulated avobenzone as a UV protection filter
In this study, hierarchically mesoporous silica (HMS) with properties such as high specific surface area, high photostability, and no cellular toxicity was synthesized. The synthesized silica can be considered as an excellent carrier candidate material. Through the use of nitrogen adsorption and desorption analysis, the shape of the hysteresis loop implied the presence of mesoporous structures in the HMS powder. In addition, the encapsulation efficiency was more than 90%. These results showed that avobenzone could be encapsulated into the HMS powder because of its high specific surface area and pore volume. Additionally, X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and UV-visible (Vis) spectrophotometry were used to prove that the hierarchically mesoporous silica was able to effectively encapsulate avobenzone. In addition, the new synthetic sunscreen kept its excellent UVA absorption properties after being encapsulated.This study provides a preparing method for mesoporous silica to effectively encapsulate with avobenzone. 相似文献
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The treatment of posterior canal benign paroxysmal positional vertigo often involves repositioning maneuvers and exercises; however, these procedures may not be suitable for patients with limb disabilities or back disorders, or for elder patients. We sought to develop a simple therapeutic maneuver as an alternative procedure, suitable for patients with a wide range of physical ability. A simple therapeutic maneuver, supine to prolonged lateral position, was developed based on the mechanism of canalolithiasis. Its efficacy in treating posterior canal benign paroxysmal positional vertigo was evaluated in a prospective study consisting of 81 objective and 13 subjective posterior canal benign paroxysmal positional vertigo patients. A successful outcome was defined as a negative Dix-Hallpike test within 2 weeks followed by the continued absence of symptoms of vertigo or dizziness for the next 4 weeks. Seventy-two patients with objective posterior canal benign paroxysmal positional vertigo and all 13 patients with subjective posterior canal benign paroxysmal positional vertigo were successfully treated: resolution rates were 88.9 and 100 %, respectively. In the objective group, negative Dix-Hallpike tests were obtained at 1 and 2 weeks in 66.7 and 88.9 % of patients, respectively. In the subjective group, the percentages of patients free of side-dependent vertigo illusions at 1 and 2 weeks were 84.6 and 100 %, respectively. These results suggest that the supine to prolonged lateral position maneuver, which is easy to perform and generally well tolerated, could be recommended as an alternative treatment modality for patients with posterior canal benign paroxysmal positional vertigo. 相似文献
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