To prepare the collagen‐based artificial cornea with improved mechanical and biological property by ultraviolet‐A/riboflavin crosslinking

In the present study, we optimized the ultraviolet‐A (UVA)/riboflavin crosslinking for the collagen‐based artificial cornea for the first time to resolve the lack of donor cornea for corneal disease. We found that the crosslinking conditions, including irradiation time and irradiation intensity, played important roles on the property of the sample. At the optimal condition (with the irradiation time of 30 min and the irradiation intensity of 5 mW/cm²), the sample exhibited excellent crosslink degree and mechanical property while keeping good light transmittance. Meanwhile, the sample showed improved enzyme tolerance capacity and thermal stability. This developed artificial cornea also had good biocompatibility to human corneal epithelial cells in vitro . In vivo lamellar keratoplasty results showed that the developed sample could promote complete epithelialization in about 4 weeks, and the transparency is restored quickly in the first 6 weeks. Corneal rejection reaction and keratoconus are not observed. This optimized UVA/riboflavin crosslinking method would have great potential for collagen‐based artificial cornea in clinic. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45226.     

Analysis of erythemal UVB and UVA irradiance at Beer Sheva,Israel from 1994 through 2012

The erythemal UVB and UVA irradiance monitored at Beer Sheva, Israel from June 1994 through March 2012 has been analyzed. A statistical analysis was applied to the daily values for each month and average, median, standard deviation, coefficient of variation (%), maximum and minimum values are reported. The maximum and minimum monthly average daily values for both erythemal UVB and UVA occur in June and December, respectively. They are 1.658 Wm⁻²(ER) and 0.346 Wm⁻²(ER) for the case of erythemal UVB and the corresponding values for UVA are 300.78 Wm⁻² and 135.52 Wm⁻². A similar statistical analysis was performed on the monthly average daily values throughout the time interval of this study. In addition, the monthly average daily values were analyzed to determine if there existed any trends for the individual months. A linear regression analysis was applied to the monthly average daily erythemal UVB and UVA irradiance as a function of year. No statistically significant trends were observed, based upon the corresponding p-values; a possible exception being the UVA irradiance during February, which may have a slight negative trend. Typical erythemal UVB and UVA irradiance meteorological years were developed for Beer Sheva and its environs.     

Relationship between UVA protection and skin response to UV light: proposal for labelling UVA protection

Definition and validation of a most relevant method to assess ultravoilet A (UVA) protection is a major concern for industry, authorities and consumers. However, due to the lack of knowledge about all the biological phenomena involved, the level of UVA protection needed, the ways to assess and label it, remain controversial. In order to overcome this situation, the paper deals with the outcomes of a mathematical model to calculate the distribution between ultravoilet B (UVB) and UVA components of skin responses to UV light. Mathematical calculations of UVB and UVA erythemal components of skin response to sunlight are developed from the well-known determination procedure to calculate the sunburn protection factor (SPF) of sunscreens. The model establishes the relationship between the UVA component of skin erythemal response to overall UV radiation received from sunlight and the ratio SPF/PFAe (erythemal protection factor) where SPF is the product and PFAe is related to the UVA part of the sunlight. Depending on the efficacy profile of sunscreens, the skin erythemal response may be mainly promoted by UVB rays as it normally occurs in unprotected skin or on contrary by UVA rays. Therefore, the efficacy profile of sunscreens defines the deepness where biological events induced by sunlight take place. This new relationship pinpoints the tremendous importance of the protection afforded by sunscreen products in the UVA range when erythema is taken as biological response. By extrapolation of the model to any other biological skin response it becomes possible to predict how to improve the efficiency of sunscreen products in the future. UVA protection afforded by sunscreens should be improved until reaching the same level as the SPF protection factor so that all UV-induced biological responses could be prevented or lowered at the same extend. To enforce this improvement, a proposal to classify sunscreen products in relation with their UVA protection is made.     

Sunscreen in vitro spectroscopy: application to UVA protection assessment and correlation with in vivo persistent pigment darkening

In the present study, we have described an in vitro spectroscopic method to evaluate the sunscreen products for UVA sun protection factor. The roughened PMMA plates have been used as a transparent substrate on to which the test product is spread. The UVA protection factors have been deduced from the UV-transmittance data measured in the UVA area. In order to be as close as possible to the in vivo protection factors, issued from the PPD end-point, the treated polymethylmethacrylate (PMMA) plates are submitted to different UV-irradiation doses, before the measurement. The correlation in vitro/in vivo is poor when the sunscreens are not irradiated. A UV dose of about 2 minimal pigmenting dose (MPD) is enough to achieve a good correlation between in vitro and in vivo data issued from the 13 tested sunscreens. These results are consistent with the fact that the photostability of sunscreens is challenged during an in vivo PPD test.     

四旋翼无人机飞控系统的研究与实现

本文通过数学建模进行动力学系统分析,研究实现了基于硬件和软件的四旋翼无人机飞控系统。首先、构建了四旋翼无人机动力学模型并进行理论分析;其次、设计了无人机机架,对各组成模块进行测试、分析和试验;再次、通过集成软硬件实现了无人机飞控系统并进行飞行测试;最后、实验结果表明,实现的无人机飞控系统取得了较好的飞控效果,具有灵敏性强、稳定性高,总体性能优良等优点。     

防晒产品抗紫外线效能的研究

采用紫外分光光度法和体外ＳＰＦ测定法分别研究了ＵＶＢ和ＵＶＡ防晒剂紫外光谱特性;ＵＶＢ、ＵＶＡ防晒剂、成膜剂以及防晒时间对防晒产品ＳＰＦ的影响。结果表明：ＵＶＢ和ＵＶＡ复配可明显提高对紫外线的吸收能力;在含ＵＶＢ的防晒产品中加入ＵＶＡ防晒剂可显提高防晒产品ＳＰＦ值;防晒时间对部分防晒产品ＳＰＦ值有一定的影响;成膜剂能使防晒产品ＳＰＦ同线显上升。上述实验结果对进一步探讨防晒产品抗紫外线效能具有重     

基于GAN的无人机航拍图像重建

传统无人机采集传输过程中所传输的数据量常常造成无人机电池的高消耗。针对此类问题,文中提出一种融合超分辨重建和灰度图像彩色化的CsRGAN模型。通过生成网络对低分辨的灰度图像进行重建:先将图片进行分辨率放大,再进行色彩填充,然后通过判别器进行图片修正,最终将图片重建为彩色高清图像。实验结果表明,在固定区域下,所提出的模型能够在保证成像质量的同时减少无人机航拍的传输数据量,提高无人机的电池利用率,且模型具有较强的鲁棒性。     

紫外线防护剂Solarine混合物

随着人们对紫外线的认识以及自我防护意识的增强,对防晒品的要求也越来越高,这促使配方设计师不断改进配方技术,采用新原料来不断满足消费者的需求。介绍了新型紫外线防护剂Solarine混合物的组成、性能特点以及在防晒品中的功效。指出Solarine混合物能有效吸收UVB和UVA,从而抵御阳光侵害。     

Photocatalytic and electrochemically assisted photocatalytic oxidation of formic acid on TiO2 films under UVA and UVB irradiation

Titanium dioxide (TiO₂) photocatalysis is a possible alternative/complementary technology for water purification. Attempts to increase the overall efficiency of the process include using higher energy UV to gain better quantum efficiency and electrochemically assisting the process by the application of an external electrical potential. In this work, nanocrystalline TiO₂ films, prepared on borosilicate glass and indium-doped tin oxide (ITO) borosilicate glass, were used to investigate the photocatalytic and electrochemically assisted photocatalytic oxidation of formic acid under UVA and UVB irradiation. The experiments were carried out in a stirred tank reactor with high mass transfer characteristics. The rate of formic acid oxidation under UVB irradiation was 30% greater as compared to UVA irradiation. A maximum Φ_app of 9% was obtained under UVA irradiation in 100% O₂ under open circuit or +1.0 V (SCE) applied potential. A maximum Φ_app of 20.3% was obtained under UVB irradiation with 100% O₂ using TiO₂ on borosilicate glass. Φ_app was 19% for +1.0 V, 100% O₂, using TiO₂ on ITO borosilicate glass under UVB irradiation. The increase in oxidation rates and Φ_app with UVB irradiation are due to the higher extinction coefficient of TiO₂ at shorter wavelengths and/or the promotion of conduction band electrons to higher more stable states, thus reducing the rate of recombination of charge carriers. The use of a UVB source as compared to a UVA source results in a significant increase in the rate of oxidation and increased apparent quantum yields, however, a cost analysis of the process would be required to determine the economic viability of employing UVB sources. Electrochemically assisted photocatalysis may prove beneficial in large-scale reactors where mass transfer limitations exist.