Zur Reproduzierbarkeit des Lichtschutzfaktors

Reproducibility of Light-Protection Factor The determination of light-protection factor, which is carried out in erythema-threshold experiment under artificial UV radiators, has become a common practice for assaying light protecting agents. Varying results may be obtained due to different sources of radiation and distribution of doses, locally varying intensity of radiation and proneness to erythema, different thickness of the applied layers and mode of reading off as well as statistical deviation from the true mean values, dependent on the number of tested persons. For a better comparability, the experimental conditions should be standardized as far as possible, and apart from the mean value, also the doubled mean error of the mean value should be given.     

Über die Lichtschutzwirkung oxalkylierter p-Amino-benzoesäureester

Light Protecting Action of Oxalkylated p-Amino-Benzoic Acid Esters The oxethylation or oxpropylation of esters of p-amino-benzoic acid in the presence of catalytic amounts of alkali leads to the formation of water soluble and oil soluble light protecting agents respectively, having the maximum absorption in the region of about 305 to 308 mμ. The absorptive behaviour of these substances, which have a very minute phase difference of only 8 mμ, lies very close to the mean erythema activity curve having the maximum of absorption at 297 mμ, as suggested by IBK. Oxethylated p-amino-benzoic acid esters are practically non-toxic and affable to skin.     

具有防晒功能的植物源成分研究进展

综述了紫外损伤皮肤机理,并针对机理总结了具有防晒功能的植物源成分。提出了具有紫外过滤特性的植物源成分可被用来替代或减少合成防晒剂的用量。除紫外吸收特性外,植物源成分具有降低DNA损伤、抗炎、抗氧化、抑制光老化和红斑的防晒增效作用,能进一步减少紫外辐射对皮肤造成的损伤。     

Beurteilung von lichtschutzsystemen bei polyolefinen in der natürlichen und künstlichen bewitterung

Vestolen A 6016 and Vestolen P 5200 were acceleratedly weathered in a Xenotext 1200 and a Xenotest 450. By variation of operating conditions of Xenotest 1200 different spectral distributions in the UV region (with and without UV filter) were obtained. In Xenotest 450 polyethylene and polypropylene showed approximately the same process of damage, wheras polyethylene and polypropylene showed clear different “spectral sensitivities” in Xenotest 1200. The maximum of UV capacity which is possible in Xenotest 1200 enables a maximum of time accelerating effect - also when light protecting systems are used - but it does not admit a more exact evaluation of the quality of a light protecting formulation. The test of light protecting formulations based on UV absorber, HALS and combinations thereof showed, that evaluation can be very different and does not always conform with the results of out door weathering.     

Der Einfluß von Antioxidantien auf die Wirkung von UV-Absorbern in verschiedenen Lacksystemen

Influence of Antioxidants on the Action of UV-Absorbers in Various Coating Systems Antioxidants on the basis of amines are undesirable as components of complex UV-absorbers due to their low stability in light. The stability of phenolic antioxidants is largely dependent on the structure of their substituents. Bis-(3,5-ditert.-butyl-4-hydroxy-benzyl)-derivatives of malonic esters, cyanoacetic esters and phosphonoacetic esters possess a good stability in heat and light and they exhibit a certain UV stabilizing action even when used alone. The author investigated the influence of these phenols on the action of UV-absorbers in various coating systems. It could be established in general that although the above phenols improved the action of UV-absorbers, however, they could not even partially substitute the latter without diminishing their action.     

Photografting of unable‐to‐be‐irradiated surfaces. I. Batch vapor‐phase process by one‐step method

Surfaces unable‐to‐be‐irradiated are those that could not be directly exposed to UV irradiation because of their irregular structure or instability under UV irradiation. It is difficult to conduct surface photografting on these kinds of surfaces with conventional photografting methods. Here, a novel one‐step surface photografting method is introduced, by which some monomers were smoothly grafted on the surface of polymer substrates located in a region out of the reach of UV radiation. The mechanism is that the photochemical reaction is separated into three events, absorbing UV light in one place, then transporting light energy to another place, and reacting there; in other words, the conventional photochemical reaction is separated by space and time, and the key point is that the substrate does not need to be exposed to UV irradiation. The occurrence of grafting polymerization was proved by UV–vis, ATR‐IR, SEM, XPS, and water contact angle measurements. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2269–2276, 2006     

气固相光催化氧化反应动力学分析

对气固相光催化氧化基元反应进行了动力学分析 ,建立了简单适用的动力学模型 .理论分析表明 ,在较低的紫外光强度下 ,光催化反应速率与光强成正比 ;在较高的光强度下 ,速率与光强的平方根成正比 ;在极高光强度下 ,速率与光强无关 .因此将光催化反应简单分解为 3个速率步骤 ,即光子传递步骤、表面作用步骤、扩散步骤 .设计了新颖的气固相光催化反应器 ,采用三氯乙烯 (TCE)为模拟污染物 ,实验结果验证了气固相光催化反应存在光子传递和表面作用控制步骤     

Fernblock, a nutriceutical with photoprotective properties and potential preventive agent for skin photoaging and photoinduced skin cancers

Many phytochemicals are endowed with photoprotective properties, i.e., the capability to prevent the harmful effects of excessive exposure to ultraviolet (UV) light. These effects include photoaging and skin cancer, and immunosuppression. Photoprotection is endowed through two major modes of action: UV absorption or reflection/scattering; and tissue repair post-exposure. We and others have uncovered the photoprotective properties of an extract of the fern Polypodium leucotomos (commercial name Fernblock). Fernblock is an all-natural antioxidant extract, administered both topically (on the skin) or orally. It inhibits generation of reactive oxygen species (ROS) production induced by UV including superoxide anion. It also prevents damage to the DNA, inhibits UV-induced AP1 and NF-κB, and protects endogenous skin natural antioxidant systems, i.e., CAT, GSH, and GSSR. Its photoprotective effects at a cellular level include a marked decrease of UV-mediated cellular apoptosis and necrosis and a profound inhibition of extracellular matrix remodeling. These molecular and cellular effects translate into long-term inhibition of photoaging and carcinogenesis that, together with its lack of toxicity, postulate its use as a novel-generation photoprotective nutriceutical of phytochemical origin.     

一款含鲜奶面霜缓解皮肤红斑反应的功效评价研究

采用客观仪器评价方法对含鲜奶面霜单次使用后的缓解皮肤红斑反应的功效进行研究。选择30名18~55周岁有效受试者为研究对象,使用胶带粘贴及组胺刺激构建皮肤红斑反应模型,并采用无创仪器的方式检测并记录实验组、安慰剂组、阴性组及空白组受试者在组胺造模前、造模后、涂抹产品后30 min和60 min时的皮肤红斑指数EI值、皮肤敏感度值,采集皮肤图像,通过SPSS数据统计软件对实验结果进行统计分析。结果显示,含鲜奶面霜可以持续改善皮肤红斑指数EI值和皮肤敏感度,缓解由组胺导致的皮肤红晕反应,说明其具有一定的缓解皮肤红斑反应,改善皮肤敏感状态的功能。     

一种新型含肉桂酸酯结构的螺吡喃光致变色染料的合成与性能研究

A novel bifunctional dye containing spirobenzopyran and cinnaznoyl moiety has been prepared and its photochromic behavior following irradiation at different wavelengths of monochrome UV light was investigated.The colourless bifunctional dye in film or solution exhibits unusual photochromism through structural and geometrical transformation from spirobenzopyran to merocyanine accompanying with photocrosslinking reaction in cinnamoyl moieties. Two kinds of photochemical reaction were achieved by irradiation at the different wavelengths of monochrome UV light (275 nm, 365 nm) selectively. The photochromic process of the bifunctional dye was discussed and the dynamic behaviors of the decolorization process were investigated.     

一款抗紫外线和抗蓝光的复合植物提取液功效研究

使用川芎根提取物、虎杖提取物、黄芩根提取物、槐花蕾提取物,制备了一款抗紫外线和抗蓝光的复合植物提取液,并对其功效进行实验研究。研究结果表明,5%复合植物提取液对UVB波段平均吸光度为0.368 4,其SPF值约为2.67,对400~440 nm高能蓝光波段的吸光度值大于1,可以完全吸收此波段的蓝光;6%的复合植物提取液对超氧自由基的清除率达88.27%、对酪氨酸酶活性的抑制率达61.81%。含5%复合植物提取液的乳液,未经防护在紫外光照射后持续使用2周,皮肤红斑量、弹性损伤、皮肤粗糙度较自然代谢分别降低了35.82%、67.51%、107.14%;复合植物提取液在45 ℃的烘箱内储藏8周后,性状稳定,无明显变化。     

Über den Einfluß von Licht verschiedener Intensität und Wellenlängenbereiche auf den oxydativen Verderb von Speiseölen II: Versuchsergebnisse und Diskussion

Influence of Light of Varying Intensity and Wavelength on the Oxydative Deterioration of Edible Oils II: Experimental Results and Discussion Since the action of light is a major cause for the deterioration of oils and fats, light-catalyzed oxidation of refined soybean oil was carried out under defined conditions of intensity and wavelength and the quantum yields were calculated. Not only was the intensity of light varied at a constant wavelength but also, in contrast to hitherto known work, the quantum density was held constant at various wavelengths. The photochemical action was dependent on the wavelength and the former increased with decreasing wavelength to a much greater extent than as might have been expected from the energy content of the light quantum.     

Statistical optimization of process conditions for photocatalytic degradation of phenol with immobilization of nano TiO<Subscript>2</Subscript> on perlite granules

Response surface methodology (RSM) using D-optimal design was applied to optimization of photocatalytic degradation of phenol by new composite nano-catalyst (TiO₂/Perlite). Effects of seven factors (initial pH, initial phenol concentration, reaction temperature, UV irradiation time, UV light intensity, catalyst calcination temperature, and dosage of TiO₂/perlite) on phenol conversion efficiency were studied and optimized by using the statistical software MODDE 8.02. On statistical analysis of the results from the experimental studies, the optimum process conditions were as follows: initial pH, 10.7; initial phenol concentration, 0.5 mM; reaction temperature, 27 °C; UV irradiation time, 6.5 h; UV light intensity, 250 W; catalyst calcination temperature, 600 °C; and TiO₂/perlite dosage, 6 g/L. Analysis of variance (ANOVA) showed a high coefficient of determination (R²) of 91.8%.     

Kinetics of ‘living’ radical polymerizations of multifunctional monomers

The polymerizations of multifunctional monomers with an iniferter, p-xylylene bis-(N,N-diethyldithiocarbamate) (XDT), were studied with differential photocalorimetry. The iniferter was used to simulate a ‘living’ radical polymerization. The normal autoacceleration behavior that is often observed in the polymerization of multifunctional monomers was not evident in the reactions with the iniferter. The reversible reaction between the propagating polymer chain and the sulfur radical from the XDT molecule dominated the reaction and drastically decreased the rate of polymerization. Various parameters of the reaction (length between functional groups in the monomer, iniferter concentration, UV light intensity, and temperature) were investigated to determine the effect on the polymerization. The rate of polymerization and the final conversion of the polymer were increased significantly by increasing the temperature, initiator concentration and UV light intensity, and decreasing the length between functional groups. Mechanical properties of the resulting polymers were also examined. It was concluded that the presence of the iniferter during the polymerization of the multifunctional monomers had no effect on the heterogeneity of the polymer network. This was in agreement with previous modeling results.     

大鲵糖肽润肤霜的制备及性能评价

通过添加大鲵糖肽制备了润肤霜,探讨了大鲵糖肽的吸湿性与抗氧化性,大鲵糖肽润肤霜的抗紫外线性与豚鼠皮肤涂抹的变态反应。结果表明：在低湿度条件下,大鲵糖肽的吸湿率达3.8%,在高湿度条件下,大鲵糖肽的吸湿率达15.6%;羟基自由基清除率为50.85%;添加了大鲵糖肽在260～315 nm下具有较强紫外线吸收能力;涂抹大鲵糖肽润肤霜和大鲵糖肽的豚鼠皮肤没有出现任何的红斑和水肿,与对照组的豚鼠的皮肤一致。     

Lichtbeständige Polyurethane für integralschäume und Elastomere

Polyurethane integral skin foams and elastomers synthesized by aromatic isocyanates are resistant to the influences of weather but yellow under exposure to light. This is the reason for the use of dark pigmentation or painting as protection. UV stabilizers and reducing compounds added to the system, slow down but do not prevent discolouration. In order to avoid the expensive painting procedure, light stable integral skin foams were developed through application of aliphatic isocyanates. Foam performance and foam properties similar to those foams synthesized from aromatic isocyanates were achieved by the addition of special catalysts, so that all requirements of the market could be fulfilled.     

A facile method of shielding from UV damage by polymer photonic crystals

BACKGROUND: UV radiation is a potent and ubiquitous carcinogen, which is responsible for most of the skin cancer in the human population. General UV protection materials may produce dangerous degradation products under UV irradiation; therefore, safe, nontoxic and simple UV protection approaches are urgent requirements. RESULTS: A series of photonic crystals with stopband covering the range 200–400 nm have been fabricated which can shield radiation from the whole UV range. Both UV‐visible and ¹H NMR results confirm the effective protection from UV light of 254 nm. CONCLUSIONS: A facile method for UV protection has been demonstrated by utilizing the unusual optical properties of photonic crystals that can inhibit light propagation at a given frequency without specific requirement of chemical composition. This approach opens a new way to protect from UV damage using safe materials, which is of great significance for extending the practical applications of photonic crystals. Copyright © 2007 Society of Chemical Industry     

The Involvement of Xanthone and (E)-Cinnamoyl Chromophores for the Design and Synthesis of Novel Sunscreening Agents

Excessive UV exposure contributes to several pathological conditions like skin burns, erythema, premature skin aging, photodermatoses, immunosuppression, and skin carcinogenesis. Effective protection from UV radiation may be achieved with the use of sunscreens containing UV filters. Currently used UV filters are characterized by some limitations including systemic absorption, endocrine disruption, skin allergy induction, and cytotoxicity. In the research centers all over the world new molecules are developed to improve the safety, photostability, solubility, and absorption profile of new derivatives. In our study, we designed and synthesized seventeen novel molecules by combining in the structures two chromophores: xanthone and (E)-cinnamoyl moiety. The ultraviolet spectroscopic properties of the tested compounds were confirmed in chloroform solutions. They acted as UVB or UVA/UVB absorbers. The most promising compound 9 (6-methoxy-9-oxo-9H-xanthen-2-yl)methyl (E)-3-(2,4-dimethoxyphenyl)acrylate) absorbed UV radiation in the range 290–369 nm. Its photoprotective activity and functional photostability were further evaluated after wet milling and incorporation in the cream base. This tested formulation with compound 9 possessed very beneficial UV protection parameters (SPF_{in vitro} of 19.69 ± 0.46 and UVA PF of 12.64 ± 0.32) which were similar as broad-spectrum UV filter tris-biphenyl triazine. Additionally, compound 9 was characterized by high values of critical wavelength (381 nm) and UVA/UVB ratio (0.830) thus it was a good candidate for broad-spectrum UV filter and it might protect skin against UVA-induced photoaging. Compound 9 were also shown to be photostable, non-cytotoxic at concentrations up to 50 µM when tested on five cell lines, and non-mutagenic in Ames test. It also possessed no estrogenic activity, according to the results of MCF-7 breast cancer model. Additionally, its favorable lipophilicity (miLogP = 5.62) does not predispose it to penetrate across the skin after topical application.     

Online monitoring of the influence of the chemical structure of hindered amines on the hydrolysis of polycarbonate in a polycarbonate/poly(acrylonitrile–butadiene–styrene) blend by ultraviolet–visible spectroscopy

Without stabilization, polycarbonate (PC)/poly(acrylonitrile–butadiene–styrene) (ABS) blends are susceptible to a loss of mechanical properties after a few days of exposure to weathering conditions. ABS can be stabilized against terrestrial light by the use of hindered amines in combination with a UV absorber; such hindered amines cannot be used when PC is present in the polymer blend. The hydrolysis of PC is accelerated when a small amount of a hindered amine light stabilizer (HALS) is incorporated into the resin and is exposed to elevated temperatures. In this study, three different HALSs (Tinuvin 123, Tinuvin 770, and Tinuvin 765, Ciba, Basel, Switzerland) were used as UV stabilizers for PC/ABS blends, and their effects on the PC phase were observed with online ultraviolet–visible spectroscopy on extruded flat films. These stabilizers were compounded with the blends in a corotating twin‐screw extruder at 240°C. The molecular weight of the compounded samples was determined by gel permeation chromatography. The extent of degradation induced by the HALSs on the PC phase was found to be a function of its chemical structure. Tinuvin 123 with an amino ether functional group enhanced degradation in comparison with Tinuvin 770 and Tinuvin 765. Tinuvin 770, a secondary amine, was apt to be more reactive than Tinuvin 765, a tertiary amine, because less steric hindrance was experienced by the former. Accelerated aging of the compounded samples was performed. Decreased degradation was observed for the samples containing hindered amines; however, the HALSs alone were not effective in protecting the PC/ABS blends against harmful UV light. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011