Photoinitiation mechanisms and photogelation kinetics of blue light induced polymerization of acrylamide with bicomponent photoinitiators

Blue light induced free radical photopolymerization of acrylamide (AM) was studied using five bicomponent photoinitiators, camphorquinon, riboflavin-5′-phosphate sodium, curcumin, eosin Y, and Ru(bpy)₃Cl₂ (Ru(II)) as photosensitizer, and diphenyliodonium hexafluorophosphate or potassium persulfate as electron acceptor. Fluorescence and UV–vis spectroscopies were used in combination with molecular orbital computations to characterize the photochemical behaviors of the five bicomponent photoinitiators, explore the possible electron transfer pathways of the photoinitiation processes, and quantify photopolymerization efficiencies. Real-time photogelation behavior of poly(AM) was monitored by Photo-differential scanning calorimetry and photo-rheometry. Photogelation kinetic parameters, including dG′ (storage modulus)/dt, dG″ (loss modulus)/dt, time delay of gelation (t_d), and duration of gelation (Δt_gel), were derived from photorheological data analyses and used to identify the best bicomponent photoinitiator candidate for rapid fabrication of blue light induced photopolymerizable hydrogels for biomedical applications.     

Vertical distribution characteristics of PM in the surface layer of Guangzhou

Measurements of particulate matter(PM),i.e.,PM10,PM2.5,and PMl,have been performed on the Canton Tower,a landmark building in Guangzhou,at heights of 121 and 454 m since November 2010,using a GRIMM 180 aerosol particle spectrometer(Germany).Analyses of data from November 2010 to May2013 showed that the annual average values of PM10,PM2.5,and PMl at the observation height of 121 m above the ground were 44.1,38.2,and 34.9μg/m3,respectively,and those at 454 m above the ground were 35.7,30.4,and 27.5 μg/m3,respectively.By considering the values of the secondary concentration limits given in the Ambient Air Quality Standards issued in 2012,it was observed that the annual average values of PM10 at the observation heights of 121 and 454 m,as well as those of PM2.5 at 454 m,reached those standards.Furthermore,the over-standard amplitude of the annual average value of PM2.5 at the observation height of 121 m was 9.1%.During the observation period,the maximum daily average values of PM10,PM2.5,and PM1 at the observation height of 121 m were 183.3,144.8,and 123.8 μg/m~3,respectively,and those at 454 m were 102.8,92.7,and 86.4 μg/m3.The daily average values of PM 10 at the observation height of 454 m were not above the standards.The over-standard frequencies of the daily average values of PM10 and PM2.5 at the observation height of 121 m were 0.6%and 10.7%,respectively,and the over-standard amplitudes were 9.0%and 24.4%,respectively.The over-standard frequency of the daily average value of PM2.5 at the observation height of 454 m was 2.0%,and the over-standard amplitude was 10.4%.Accordingly,it can be stated that the air at the observation height 454 m above the ground did not reach the secondary limit of the new standards.The pollution was most serious during winter,and the air was relatively cleaner during summer.Overall,the vertical distributions of PM 10,PM2.5,and PMl decreased with height.The lapse rates showed the following sequence:PM10 > PM2.5 > PM1,which indicates that the vertical distribution of fine particles is more uniform than that of coarse particles;the vertical distribution in summer is more uniform than in other seasons.     

低Ni含量和低比表面积六铝酸盐LaNiAl_(11)O_(19-δ)催化剂上CH_4-CO_2重整反应的积炭

利用X射线粉末衍射、氢程序升温还原、X射线光电子能谱和透射电镜技术研究了在低Ni含量和低比表面积六铝酸盐催化剂LaNiAl_(11)O_(19-δ)上CH_4-CO_2重整反应的积炭行为,考察了该催化剂表面积炭的形貌、来源、积炭物种及其反应性能.结果表明,LaNiAl_(11)O_(19-δ)催化剂表面积炭主要由甲烷裂解产生,并以Ni的碳化物形式存在于活性中心Ni的周围.根据积炭物种活化程度的难易可分为C_α,C_β和C_γ三种类型,其中C_α为容易被CO_2消除的化合碳,而C_β和C_γ则是不易被CO_2消除的石墨碳.透射电镜结果表明,C_α以碳纳米管形式分布于催化剂颗粒周围,但金属Ni活性中心仍能暴露于气相中,因而不影响催化剂的活性.     

低Ni含量和低比表面积六铝酸盐LaNiAl11O19-δ催化剂上CH4-CO2重整反应的积炭

 利用 X 射线粉末衍射、氢程序升温还原、X 射线光电子能谱和透射电镜技术研究了在低 Ni 含量和低比表面积六铝酸盐催化剂 LaNiAl11O19-δ 上 CH4-CO2 重整反应的积炭行为, 考察了该催化剂表面积炭的形貌、来源、积炭物种及其反应性能. 结果表明, LaNiAl11O19-δ 催化剂表面积炭主要由甲烷裂解产生, 并以 Ni 的碳化物形式存在于活性中心 Ni 的周围. 根据积炭物种活化程度的难易可分为 Cα, Cβ和 Cγ 三种类型, 其中 Cα 为容易被 CO2 消除的化合碳, 而 Cβ 和 Cγ则是不易被 CO2 消除的石墨碳. 透射电镜结果表明, Cα 以碳纳米管形式分布于催化剂颗粒周围, 但金属 Ni 活性中心仍能暴露于气相中, 因而不影响催化剂的活性.     

THE C~(1,α) REGULARITY OF SOLUTIONS TO DOUBLE OBSTACLE PROBLEM OF VARIATIONAL INEQUALITY

In this paper, a double obstacle problem of variational inequalities is considered and its solutions is obtained. The results of one-sided obstacle problem are not required in the analysis of our main results, which is different from the previous works.     

Study on the Radius of an Electrical Spherical Micelle： Functional Theoretical Approach

For the purpose of eliminating restriction, the Poisson-Bokzmann (PB) equation, which represents the potential of the electrical double layer of spherical miceUes, can be solved analytically only under the lower potential condition, a kind of iterative method in functional analysis theory has been used. The radius of the spherical particle can be obtained from the diagram of the second iterative solution of the potential versus the distance from the center of the particle. The influences of the concentration of the ions, the charge number of ions, the aggregation number of the particle, the dielectric constant of solvent and the temperature of system on the radius also have been studied.     

带有偏差变元的广义Hamilton系统周期解的存在性

应用变分方法与Morse理论,本文讨论下面含有时滞的广义Hamilton系统的周期解,J*du-dt=g(t,u(t-r1),…,u(t-rs))其中J*是非奇异2n×2n反对称矩阵.在一定条件下,本文得到上述方程至少存在两个非平凡2π-周期解而对于一般的微分系统,本文给出其具有变分结构的判定性准则.     

Asiatic Acid Glucosamine Salt Alleviates Ultraviolet B-induced Photoaging of Human Dermal Fibroblasts and Nude Mouse Skin

Herbal extracts including asiatic acid (AA) have become popular candidates of anti-photoaging agents due to their anti-inflammatory and antioxidant properties and minimal side effect. Nevertheless, low bioavailability due to poor solubility limits their practical application. In this study, a highly bioavailable form of AA called AAGS (compounded by asiatic acid and glucosamine) was investigated for its anti-photoaging effect using both in vitro and in vivo models along with UVB irradiation. The results showed that AAGS alleviated UVB-induced cell proliferation inhibition by reducing G2 phase arrest and cell apoptosis rate as well as the gene expressions of P53, BAX, CASPASE 3 and CASPASE 9, but enhancing BCL-2 expression. It also reduced the production of reactive oxygen species along with increased gene expression of GPX-1 and downregulated the gene expression of IL-1β, IL-6, IL-8, IL-17 and TNF-α compared to nontreated cells. In vivo results demonstrated the antiphotodamaging effects by restoring skin thickness, collagen content and reducing MMPs expression, which are also supported by reduced MMPs gene expression and enhanced collagen I and TGF-β1 gene expression in vitro. Thus, AAGS may become a potential anti-photoaging agent for topical use due to its capability of self-assembling into a water gel.     

混合应变多量子阱有源材料及其增益偏振特性

采用MOCVD外延交替生长了压应变、张应变In_xGa1-xAs_yP1-y多量子阱材料,对应1.3 μm波段.平均应变量-0.16%,周期11 nm.采用三个周期外延材料的芯片制作的LD,实现了TE和TM双偏振模激射.     

EMIMAC和HMIMCl及其水溶液热力学特性实验研究

离子液体+水作为吸收式制冷工质对具有诸多优点,其热力学性质是衡量工质对优劣及热力学计算的重要基础数据.本文研究两种水溶性离子液体EMIMAC和HMIMCl及其水溶液的热力学性质,主要对这两种离子液体及其水溶液的密度和比热进行测定.密度测试采用比重天平,比热测试采用耐驰DSC204HP低温高压差热仪,测试精度较高且测试系统稳定可靠.密度实验测试的温度范围为298.15～393.15K,比热实验测试温度范围为283.15～413.15K,测试的离子液体摩尔浓度分别为1,0.8,0.6,0.4,0.2,0.研究结果为这两种离子液体的吸收式制冷应用提供了可靠的热物性数据.