BACKGROUND & AIMS: -2

背景与目标： -2

BACKGROUND & AIMS: :The formation and reactivity of excited states and free radicals from primaquine, a drug used in the treatment of malaria, was studied in order to evaluate the primary photochemical reaction mechanisms. The excited primaquine triplet was not detected, but is likely to be formed with a short lifetime (<50 ns) and with a triplet energy <250 kJ/mol as the drug is an efficient quencher of the fenbufen triplet and the biphenyl triplet, and forms (1)O(2) by laser flash photolysis ((PQ)Phi(Delta)=0.025). Primaquine (PQ) exists as the monocation (PQH(+)) in aqueous solution at physiological pH. PQH(+) photoionises by a biphotonic process and also forms the monoprotonated cation radical (PQH(2+)*) by one electron oxidation by HO* (k(q)=6.6 x 10(9) M(-1) s(-1)) and Br*(2)(-) (k(q)=4.7 x 10(9) M(-1) s(-1)) at physiological pH, detected as a long-lived transient decaying essentially by a second order process (k(2)=7.4 x 10(8) M(-1) s(-1)). PQH(2+)* is scavenged by O(2), although at a limited rate (k(q)=1.0 x 10(6) M(-1) s(-1)). The reduction potential (E degrees) of PQH(2+)*/PQH(+) is < +1015 mV, as measured versus tryptophan (TRP*/TRPH). Primaquine also forms PQH(2+)* at pH 2.4, by one electron oxidation by Br*(2)(-) and proton loss (k(q)=2.7 x 10(9) M(-1) s(-1)). The non-protonated cation radical (PQ(+)*) is formed during one electron oxidation with Br*(2)(-) at alkaline conditions (k(q)=4.2 x 10(9) M(-1) s(-1) at pH 10.8). The estimated pK(a)-value of PQH(2+)*/PQ(+)* is pK(a) approximately 7-8. Primaquine is not a scavenger of O*(2)(-) at physiological pH. Thus self-sensitization by O*(2)(-) is eliminated as a degradation pathway in the photochemical reactions. Impurities in the raw material and photochemical degradation products initiate photosensitized degradation of primaquine in deuterium oxide, prevented by addition of the (1)O(2) quencher sodium azide. Photosensitized degradation by formation of (1)O(2) is thus important for the initial photochemical decomposition of primaquine, which also proceeds by free radical reactions. Formation of PQH(2+)* is expected to play an essential part in the photochemical degradation process in a neutral, aqueous medium.

背景与目标： : 研究了用于治疗疟疾的药物伯喹的激发态和自由基的形成和反应性，以评估主要的光化学反应机制。未检测到激发的primaquine三重态，但很可能形成寿命短 (<50 ns)，三重态能量 <250 kJ/mol，因为该药物是芬布芬三重态和联苯三重态的有效猝灭剂，并通过激光闪光光解形成 (1)O(2) ((PQ)Phi (δ) = 0.025)。Primaquine (PQ) 在生理pH下以水溶液中的单位置 (PQH ()) 存在。PQH(+) 通过双光子过程光电离，还通过HO * (k(q)= 6.6x10(9) M(-1) s(-1) 和Br *(2) 的一个电子氧化形成单质子化阳离子自由基 (PQH(2 +)*)(-) (k(q)= 4.7x10(9) M(-1) s(-1)) 在生理pH下，检测为基本上通过二阶过程衰减的长寿命瞬态 (k(2)= 7.4 × 10(8) M(-1) s(-1))。PQH(2 +)* 被O(2) 清除，尽管以有限的速率 (k(q)= 1.0 × 10(6) M(-1) s(-1))。与色氨酸 (TRP */TRPH) 相比，PQH(2 +)*/PQH(+) 的还原电位 (E度) <+ 1015 mV。在pH 2.4下，通过Br *(2)(-) 的一次电子氧化和质子损失 (k(q)= 2.7x10(9) M(-1) s(-1)，伯喹也形成PQH(2 +)*。非质子化的阳离子自由基 (PQ(+)*) 在碱性条件下 (k(q)= 4.2 × 10(9) M(-1) s(-1)) 在用Br *(2)(-) 的一次电子氧化过程中形成。pH 10.8)。PQH(2 +)*/PQ(+)* 的估计pK(a)-值约为7-8。在生理pH下，Primaquine不是O *(2)(-) 的清除剂。因此，在光化学反应中，O *(2)(-) 的自敏化作为降解途径被消除。通过添加 (1)O(2) 猝灭剂叠氮化钠，防止了原料和光化学降解产物中的杂质引发氧化氘中primaquine的光敏化降解。因此，通过形成 (1)O(2) 的光敏降解对于primaquine的初始光化学分解很重要，primaquine也通过自由基反应进行。PQH(2) * 的形成有望在中性水性介质中的光化学降解过程中发挥重要作用。

BACKGROUND & AIMS: :L-TBOA (L-threo-beta-benzyloxyaspartate) is, so far, the most potent non-transportable blocker for glutamate transporters. We synthesized alpha-CMCM-L-TBOA (1a) possessing [7-(carboxymethoxy)coumarin-4-yl]methyl ester as a caging group. alpha-CMCM-L-TBOA (1a) is biologically inactive until UV irradiation and the photolysis of 1a immediately released L-TBOA to show glutamate uptake inhibition. The photoreactivity of the coumarin-type caging group was superior to that of the o-nitrobenzyl-type caging group.

背景与目标： : L-TBOA (L-苏-β-苄基氧天冬氨酸) 是迄今为止谷氨酸转运蛋白最有效的非转运阻滞剂。我们合成了具有 [7-(羧基甲氧基) coumarin-4-yl] 甲酯作为笼形基团的 α-CMCM-L-TBOA (1a)，α-CMCM-L-TBOA (1a) 在紫外线照射和1a的光解作用下立即释放L-TBOA以显示谷氨酸吸收抑制之前是生物活性的。香豆素型笼基的光反应活性优于邻硝基苄基型笼基。

BACKGROUND & AIMS: :A newly synthesized linear psoralen derivative, 3-carbethoxypsoralen is shown to bind to yeast nucleic acids after 365 nm light treatment. As compared to 8-methoxypsoralen, a well-known bifunctional furocoumarin, 3-carbethoxypsoralen exhibits a high photoaffinity for DNA in vivo. Both compounds bind and photoreact more efficiently in vivo than in vitro. In contrast to 8-methoxypsoralen, 3-carbethoxypsoralen does not form cross-links in yeast DNA as demonstrated by heat denaturation-reassociation studies at least in the range of doses used. Thus 3-carbethoxypsoralen reacts as a monofunctional compound. Wild-type cells of Saccharomyces cerevisiae are 6 times more resistant to 3-carbethoxypsoralen than to 8-methoxypsoralen plus 365 nm light treatment in terms of lethal effect. In comparison to angelicin, another monofunctional (but angular) furocoumarin, 3-carbethoxypsoralen is more photoreactive. When the photoaffinity for DNA of 8-methoxypsoralen and 3-carbethoxypsoralen are considered in relation to photoinduced cell killing, it is clear that monoadducts are very efficiently repaired in wild-type cells. In contrast to the additivity obtained with 8-methoxypsoralen, a synergistic interaction of the two different repair pathways blocked by the rad2 and the rad9 mutation is observed after 3-carbethoxypsoralen plus 365 nm light. Dark holding experiments show that the excision repair function which is present in wild-type and rad9-4 cells is important for dark recovery.

背景与目标： : 新合成的线性补骨脂素衍生物3-碳氧补骨脂素显示在365 nm光处理后与酵母核酸结合。与8-甲氧基补骨脂素相比，一种众所周知的双功能呋辛香豆素，3-碳氧补骨脂素在体内对DNA具有很高的光亲和力。两种化合物在体内的结合和光反应比在体外更有效。与8-甲氧基补骨脂素相反，3-碳氧补骨脂素在酵母DNA中不形成交联，至少在所用剂量范围内进行了热变性-再结合研究。因此，3-碳氧基对甲素作为单官能化合物反应。就致死效果而言，酿酒酵母的野生型细胞对3-碳氧补骨脂素的抗性是对8-甲氧基补骨脂素加365 nm光处理的抗性的6倍。与当归素相比，另一种单功能 (但有角度) 的呋辛香豆素3-碳氧基补骨素具有更高的光反应性。当考虑到与光诱导的细胞杀伤有关的8-甲氧基补骨脂素和3-甲氧基补骨脂素对DNA的光亲和力时，很明显，单加合物在野生型细胞中得到非常有效的修复。与用8-甲氧基补骨脂素获得的可加性相反，在3-甲氧基补骨脂素加365 nm光后，观察到被rad2和rad9突变阻断的两种不同修复途径的协同相互作用。暗保持实验表明，野生型和rad9-4细胞中存在的切除修复功能对于暗恢复很重要。

BACKGROUND & AIMS: :Side effects of nitroaromatics used as drugs are often assumed to be caused by incomplete enzymatic reduction of the nitro group. However, photoactivation, although usually not considered as a cause of the toxic effects of nitroaromatics, can play a considerable role. Nifedipine, a nitroaromatic as well, is an important drug used in the treatment of myocardial ischaemia and hypertension. It is extremely sensitive to ultraviolet and visible light up to 450 nm and forms a nitroso derivative in vitro. In the present study it is shown that the nitroso compound is a short-lived intermediate in blood and plasma. It reacts with other constituents to form a stable lactam. In vivo, this lactam proves to be rapidly clear from the blood of rats and is excreted almost quantitatively via the bile. The first photoproduct of nifedipine, nitroso nifedipine, is shown to be converted into the lactam mentioned. Beside the lactam, two other products, which are considered to be derivatives of the lactam, are found. One of these two products is also found in the bile of a rat that was exposed to UVA light after intravenous nifedipine administration. This shows that in an in vivo situation, photoproducts can reach organs other than those exposed to the light. In vitro about 45 to 50% of the original amount of nifedipine is not recovered after exposure of nifedipine to UVA in the presence of bovine serum albumin or after incubation of nitroso nifedipine with bovine serum albumin in the dark. As complex binding of nifedipine of plasma proteins is high, the latter finding may have important implications for the situation in vivo.

背景与目标： : 用作药物的硝基芳烃的副作用通常被认为是由于硝基的酶促还原不完全引起的。然而，光活化虽然通常不被认为是硝基芳烃毒性作用的原因，但可以发挥相当大的作用。硝苯地平也是一种硝基芳香族化合物，是用于治疗心肌缺血和高血压的重要药物。它对高达450 nm的紫外线和可见光极为敏感，并在体外形成亚硝基衍生物。在本研究中，表明亚硝基化合物是血液和血浆中的短暂中间体。它与其他成分反应形成稳定的内酰胺。在体内，这种内酰胺被证明可以从大鼠的血液中迅速清除，并几乎通过胆汁定量排泄。硝苯地平的第一个光产物硝苯地平被证明转化为提到的内酰胺。除了内酰胺外，还发现了另外两种被认为是内酰胺衍生物的产物。在静脉注射硝苯地平后暴露于UVA光的大鼠胆汁中也发现了这两种产品之一。这表明在体内情况下，光产物可以到达暴露于光的器官以外的器官。在牛血清白蛋白存在下将硝苯地平暴露于UVA后或在黑暗中将硝苯地平与牛血清白蛋白孵育后，在体外未回收约45至50% 的原始量的硝苯地平。由于血浆蛋白中硝苯地平的复杂结合很高，后者的发现可能对体内情况具有重要意义。

BACKGROUND & AIMS: :The influence of solvent interactions on absorption properties, fluorescence properties (emission spectra and quantum yields) and relative photochemical degradation rates of primaquine has been investigated, in order to evaluate photochemical reaction mechanisms and chemical properties of the compound. The first absorption band (n - pi*) of primaquine is only slightly dependent on properties of the solvent, which can be ascribed to a strong, intramolecular hydrogen bond between the quinoline N and amine group in the ground state (S0). Amphiprotic solvents with predominant acidic properties (water and methanol) will to some extent stabilize the molecule and initiate hypsochromic shifts of the absorption band by protic interactions, while the other solvents (amphiprotic, basic and neutral) influence the absorption spectrum by general solvent effects only. The excited singlet (S1*) state of primaquine interacts more efficiently with the surrounding solvents than the S0 state, as evaluated by the Stokes shifts. The pKa value of the quinoline N is likely to increase in the S1* state, which is important for the observed protic interactions with amphiprotic solvents of predominant acidity. Specific solvent effects are highly important for the efficiency of the fluorescence (fluorescence quantum yields; phi f). The fluorescence is quenched by amphiprotic solvents, likely due to a rupture of the intramolecular bond and protonation of the quinolone N, and enhanced by polar, non-protic (basic) solvents, probably by stabilization of the delta intramolecular hydrogen bond. The observed photochemical degradation rates of primaquine in amphiprotic media are positively correlated with phi f, indicating that the photochemical degradation of primaquine is dependent on intramolecular hydrogen bonding and non protonated lone-pair electrons at the quinoline N. The intramolecular ring-formation with a subsequent increased lipophilic character and (lack of) interactions with the surroundings, are important factors for biological behavior as well as pharmaceutical properties of primaquine. Knowledge about solvent interactions with primaquine in the S0 and S1* states is essential for the proceeding evaluation of photostability and phototoxicity of the drug.

背景与目标： 研究了溶剂相互作用对primaquine的吸收性能、荧光性能 (发射光谱和量子产率) 和相对光化学降解速率的影响，以评价该化合物的光化学反应机理和化学性质。primaquine的第一吸收带 (n - pi *) 仅略微取决于溶剂的性质，这可以归因于喹啉N和基态 (S0) 的胺基之间的强分子内氢键。具有主要酸性 (水和甲醇) 的双质子溶剂将在一定程度上稳定分子并通过质子相互作用引发吸收带的低变色移动，而其他溶剂 (双质子，碱性和中性) 仅通过一般溶剂影响吸收光谱。根据斯托克斯位移评估，primaquine的激发单线态 (S1 *) 与周围溶剂的相互作用比S0态更有效。喹啉N的pKa值可能在S1 * 状态下增加，这对于观察到的质子与主要酸度的双质子溶剂的相互作用很重要。特定的溶剂效应对于荧光效率 (荧光量子产率; phi f) 非常重要。荧光被双质子溶剂猝灭，这可能是由于分子内键的破裂和喹诺酮N的质子化，并被极性非质子 (碱性) 溶剂增强，可能是通过稳定 δ 分子内氢键。观察到的两质子介质中primaquine的光化学降解速率与phi f呈正相关，表明primaquine的光化学降解取决于分子内氢键和非质子化的孤对电子在喹啉N上。分子内环的形成以及随后的亲脂性增强和 (缺乏) 与周围环境的相互作用，是生物行为以及primaquine的药物特性的重要因素。了解S0和S1 * 状态下与primaquine的溶剂相互作用对于继续评估药物的光稳定性和光毒性至关重要。

BACKGROUND & AIMS: :The complexes of NO with CuB of cytochrome c oxidase in which cytochrome a3 may or may not be ligated to cyanide or fluoride are photodissociable. NO does not appear to react with CuB in complexes of cytochrome c oxidase in which sulphide or mercaptans are ligated to the haem iron of cytochrome a3. A comparison is made between the photoreactivity of the complexes of NO with cytochrome c oxidase and those with ceruloplasmin, ascorbate oxidase, and haemocyanin. It is shown that the photoreactivity of CuB 2+.NO in cytochrome c oxidase is not unique for this enzyme, but may also be observed in the complexes of NO with type-1 copper-containing enzymes. This would suggest that the ligation of CuB in cytochrome c oxidase shows some similarity to type-1 copper in blue oxidases.

背景与目标： : NO与细胞色素c氧化酶CuB的复合物是可光解的，其中细胞色素a3可能与氰化物或氟化物连接或不连接。NO似乎不会与细胞色素c氧化酶配合物中的CuB反应，其中硫化物或硫醇与细胞色素a3的血红素铁连接。比较了NO与细胞色素c氧化酶的配合物与铜蓝蛋白，抗坏血酸氧化酶和血色素的配合物的光反应活性。结果表明，细胞色素c氧化酶中CuB 2.NO的光反应不是该酶唯一的，但也可以在NO与1型含铜酶的复合物中观察到。这表明CuB在细胞色素c氧化酶中的连接与蓝色氧化酶中的1型铜有些相似。

BACKGROUND & AIMS: :Coherent multidimensional electronic spectroscopy is commonly used to investigate photophysical phenomena such as light harvesting in photosynthesis in which the system returns back to its ground state after energy transfer. By contrast, we introduce multidimensional spectroscopy to study ultrafast photochemical processes in which the investigated molecule changes permanently. Exemplarily, the emergence in 2D and 3D spectra of a cross-peak between reactant and product reveals the cis-trans photoisomerization of merocyanine isomers. These compounds have applications in organic photovoltaics and optical data storage. Cross-peak oscillations originate from a vibrational wave packet in the electronically excited state of the photoproduct. This concept isolates the isomerization dynamics along different vibrational coordinates assigned by quantum-chemical calculations, and is applicable to determine chemical dynamics in complex photoreactive networks.

背景与目标： : 相干多维电子光谱学通常用于研究光物理现象，例如光合作用中的光收集，其中系统在能量转移后返回其基态。相比之下，我们引入多维光谱学来研究超快光化学过程，其中所研究的分子会永久变化。示例性地，反应物和产物之间的交叉峰在2D和3D光谱中出现，揭示了花色苷异构体的顺反光异构化。这些化合物在有机光伏和光学数据存储中具有应用。交叉峰振荡源自光积的电子激发态中的振动波包。此概念隔离了沿量子化学计算分配的不同振动坐标的异构化动力学，适用于确定复杂的光反应性网络中的化学动力学。

BACKGROUND & AIMS: :A2E (2-[2,6-dimethyl-8-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1E, 3E,5E,7E-octatetraenyl]-1-(2-hydroxyethyl)-4-[4-methyl-6(2,6,6-trimethyl-1-cyclohexen-1-yl)-1E,3E,5E-hexatrienyl]pyridinium) is a blue-absorbing molecular constituent of human ocular lipofuscin and contributes to the golden-yellow emission of this pigment. Lipofuscin photoproduces toxic reactive oxygen intermediates (ROI), but the specific molecular components responsible for this phototoxicity remain unidentified. In this article the aerobic photoreactivity of A2E is quantified by comparison with its biosynthetic precursor, all-trans-retinal, and with other appropriate standards. Under blue-light exposure the efficacies for formation of cholesterol (Ch) hydroperoxides and the superoxide radical anion (O2*-) were determined using high-pressure liquid chromatography with electrochemical detection and electron spin resonance oximetry and spin trapping, respectively. Photogeneration of singlet oxygen after blue-light excitation of A2E was demonstrated unambiguously by the Ch peroxidation assay. After blue-light irradiation of A2E, O2*- were detected, but the concentration was insufficient to account for the measured production of O2*- by the solvent extract of lipofuscin granules. The collective data support the conclusion that A2E does not produce sufficient concentrations of ROI to be the primary phototoxic constituent of lipofuscin.

背景与目标： : A2E (2-[2,6-二甲基-8-(2,6，6-三甲基-1-环己烯-1-基)-1E，3E，5E，7e-八四烯基]-1-(2-羟乙基)-4-[4-甲基-6(2,6，6-三甲基-1-环己烯-1-基)-1E，3E，5e-己三烯基] 吡啶鎓) 是人眼脂褐素的一种吸收蓝色的分子成分，有助于这种色素的金黄色发射。脂褐素光产生有毒的活性氧中间体 (ROI)，但是导致这种光毒性的特定分子成分仍然未知。在本文中，A2E的需氧光反应通过与其生物合成前体全反式视网膜进行比较来量化。和其他适当的标准。在蓝光照射下，使用高压液相色谱电化学检测，电子自旋共振血氧饱和度和自旋捕获法测定了胆固醇 (Ch) 氢过氧化物和超氧化物自由基阴离子 (O2 *-) 的形成效率。分别。通过Ch过氧化试验明确证明了A2E在蓝光激发后单线态氧的光生。在A2E的蓝光照射后，检测到O2 *-，但是浓度不足以说明脂褐素颗粒的溶剂提取物测得的O2 *-的产生。集体数据支持以下结论: A2E不能产生足够浓度的ROI作为脂褐素的主要光毒性成分。

BACKGROUND & AIMS: Wetlands are recognized for the importance of their hydrological function and biodiversity, and there is now a consensus to protect and restore them as well as to complete the knowledge on their functioning. Here, we studied the dissolved organic matter (DOM) of a wetland composed of the Auzon cut-off meander, the Allier River, the alluvial fluvial flow, and watershed aquifer. Water was sampled at different locations, in spring, summer, and autumn. For each sample, DOM was characterized for its chemical and optical properties and its photooxidant capacity through its ability to generate DOM triplet excited states (3DOM*) and singlet oxygen upon simulated solar light exposure. UV-visible and fluorescence indices revealed that DOM was mainly microbial-derived whatever the sampling sites with spatial and temporal variations in terms of aromaticity (5.5-22%), specific UV absorbance at 254 nm (0.28-2.82 L m-1mgC-1), ratio of the absorbance at 254 and 365 nm (4.6-10.8), fluorescence index (1.35-166), and biological index (0.812-2.25). All the samples generated 3DOM* and singlet oxygen, rates of formation of which showed parallel variations. Using principal component analysis (PCA), we found positive correlations between the sensitizing properties of DOM samples and parameters associated to the abundance of low molecular weight and low absorbing chromophores. Moreover, the parameter variation across the wetland reinforced the hydrological movements observed in a previous study, suggesting that these parameters could be used as water connection tracers.

背景与目标： 湿地因其水文功能和生物多样性的重要性而得到认可，现在已经达成共识，以保护和恢复湿地并完成有关其功能的知识。在这里，我们研究了由Auzon截流曲折，Allier河，冲积河流流和分水岭含水层组成的湿地的溶解有机物 (DOM)。在春季，夏季和秋季的不同位置对水进行了采样。对于每个样品，DOM的化学和光学性质以及通过在模拟太阳光照射下产生DOM三重激发态 (3DOM *) 和单线态氧的能力来表征其光氧化剂容量。紫外可见和荧光指数表明，DOM主要是微生物来源的，无论采样点在芳香性 (5.5-22%)，254 nm (0.28-2.82 L m-1mgC-1) 的特定紫外吸收，在254和365 nm处的吸光度比 (4.6-10.8)，荧光指数 (1.35-166) 和生物指数 (0.812-2.25)。所有样品均产生3DOM * 和单线态氧，其形成速率显示出平行变化。使用主成分分析 (PCA)，我们发现DOM样品的敏化特性与与低分子量和低吸收发色团的丰度相关的参数之间存在正相关。此外，整个湿地的参数变化加强了先前研究中观察到的水文运动，表明这些参数可以用作水连接示踪剂。

BACKGROUND & AIMS: :The photoreactivity of chlorothalonil was studied by means of steady-state irradiation and laser-flash photolysis. Experiments were conducted in water containing acetonitrile as a co-solvent. This fungicide undergoes very slow phototransformation in the first stages of the reaction, but the consumption profile is auto-accelerated. To understand the reaction mechanism, we undertook a detailed study of the rates, products and transient species. The rates and photoproduct distribution vary greatly with the oxygen concentration. Concerning the transient species, we measured the absorption of the triplet, its yield of formation, and its reactivity with oxygen in various water-acetonitrile mixtures and with isopropanol. The reduced radical, CTH˙, could be produced and its transient spectrum was recorded. Combining all the experimental data, it is hypothesized that in the first step of the reaction CT is excited to the triplet state. The triplet has several possible fates including reduction by organic constituents to form the radical which gives photoproducts. Another characteristic of the CT triplet is its capacity to generate singlet oxygen. The production of this species was measured by phosphorescence and compared to the percentage of the triplet trapped by oxygen in air-saturated solutions. The yield varies from 0.88 in pure acetonitrile to 0.48 in water-acetonitrile (95 : 5, v/v). Therefore, in surface waters, chlorothalonil is expected to sensitize the photooxidation of micropollutants, and to be competitively phototransformed through reaction with any H donor or electron donor water constituents.

背景与目标： : 通过稳态辐射和激光闪光光解研究了百菌清的光反应。实验是在含有乙腈作为共溶剂的水中进行的。这种杀菌剂在反应的第一阶段经历非常缓慢的光转化，但是消耗曲线是自动加速的。为了了解反应机理，我们对反应速率，产物和瞬态物种进行了详细研究。速率和光产物分布随氧气浓度的变化而变化很大。关于瞬态物质，我们测量了三重态的吸收，其形成率以及在各种水-乙腈混合物和异丙醇中与氧的反应性。可以产生还原的自由基cth ˙，并记录其瞬态光谱。结合所有实验数据，假设在反应的第一步，CT被激发为三重态。三重态有几种可能的命运，包括通过有机成分的还原形成产生光产物的自由基。CT三重态的另一个特征是它产生单线态氧的能力。通过磷光测量该物种的产量，并将其与空气饱和溶液中氧气捕获的三重态的百分比进行比较。产率从纯乙腈中的0.88到水-乙腈中的0.48 (95 :  5，v/v) 变化。因此，在地表水中，百菌清有望使微污染物的光氧化敏感，并通过与任何H供体或电子供体水成分的反应竞争性光转化。

BACKGROUND & AIMS: :Combined use of photochemical and pharmacokinetic (PK) data for phototoxic risk assessment was previously proposed, and the system provided reliable phototoxic risk predictions of chemicals in same chemical series. This study aimed to verify the feasibility of the screening system for phototoxic risk assessment on dermally-applied chemicals with wide structural diversity, as a first attempt. Photochemical properties of test chemicals, 2-acetonaphthalene, 4'-methylbenzylidene camphor, 6-methylcoumarin, methyl N-methylanthranilate, and sulisobenzone, were evaluated in terms of UV absorption and reactive oxygen species (ROS) generation, and PK profiles of the test chemicals in rat skin were characterized after dermal co-application. All test chemicals showed strong UVA/B absorption with molar extinction coefficients of over 3000 M-1⋅cm-1, and irradiated 2-acetonaphthalene, 6-methylcoumarin, and methyl N-methylanthranilate exhibited significant ROS generation. Dermally-applied 2-acetonaphthalene and 4'-methylbenzylidene camphor indicated high and long-lasting skin deposition compared with the other test chemicals. Based on the photochemical and PK data, 2-acetonaphthalene was predicted to have potent phototoxic risk. The predicted phototoxic risk of the test chemicals by integration of obtained data was mostly consistent with their in vivo phototoxicity observed in rat skin. The screening strategy employing photochemical and PK data would have high prediction capacity and wide applicability for photosafety evaluation of chemicals.

背景与目标： : 先前提出了将光化学和药代动力学 (PK) 数据联合用于光毒性风险评估的建议，该系统提供了相同化学系列化学品的可靠光毒性风险预测。这项研究旨在验证筛选系统对具有广泛结构多样性的皮肤应用化学物质进行光毒性风险评估的可行性，这是首次尝试。根据紫外线吸收和活性氧 (ROS) 产生以及PK来评估测试化学品，2-乙萘，4 '-甲基亚苄基樟脑，6-甲基香豆素，N-甲基邻氨基苯甲酸甲酯和磺基苯甲酸酯的光化学性质。真皮共同应用后，对大鼠皮肤中的测试化学品进行了表征。所有测试化学品均显示出很强的UVA/B吸收，摩尔消光系数超过3000 M-1·cm-1，辐照的2-乙萘，6-甲基香豆素和N-甲基邻氨基苯甲酸甲酯表现出明显的ROS生成。与其他测试化学品相比，皮肤上施用的2-乙萘和4 '-甲基苄基樟脑表明皮肤沉积高且持久。根据光化学和PK数据，预测2-乙萘具有强烈的光毒性风险。通过整合获得的数据，预测的测试化学品的光毒性风险与在大鼠皮肤中观察到的体内光毒性基本一致。采用光化学和PK数据的筛选策略将具有很高的预测能力，并且在化学物质的光安全性评估中具有广泛的适用性。

BACKGROUND & AIMS: :The drugs commonly used in the treatment of malaria are photochemically unstable. Several of these compounds accumulate in melanin-rich tissues and cause toxic reactions which may be light induced. As part of the screening of the photochemical properties and phototoxic capabilities of antimalarials, the in vitro interaction of eight antimalarials with melanin was studied. The dissociation constant for the drug-melanin complex and the relative number of binding sites on melanin were estimated for six of the drugs using a curve-fitting program. The reaction rate for the formation of the melanin-drug complex was determined, and the complexes were further characterized by zeta potential measurements.

背景与目标： : 治疗疟疾常用的药物光化学不稳定。这些化合物中的几种积聚在富含黑色素的组织中，并引起可能由光诱导的毒性反应。作为筛选抗疟药的光化学特性和光毒性能力的一部分，研究了八种抗疟药与黑色素的体外相互作用。使用曲线拟合程序估算了六种药物的药物-黑色素复合物的解离常数和黑色素上结合位点的相对数量。确定了黑色素-药物复合物形成的反应速率，并通过zeta电位测量进一步表征了复合物。

BACKGROUND & AIMS: :The bis-retinoid N-retinyl-N-retinylidene ethanolamine (A2E) is formed as a byproduct of visual cycle in retinal pigment epithelium (RPE). It contributes to golden-yellow fluorescence of the age pigment lipofuscin, which accumulates in RPE. Lipofuscin can generate a variety of reactive oxygen species (ROS) upon blue-light excitation. Although in model systems photoreactivity of A2E has been determined to be low, this bis-retinoid exhibited significant phototoxicity in RPE cells in vitro. Although the mechanism of A2E-mediated phototoxicity remains mostly unknown, we hypothesize that formation of A2E-adducts with different biomolecules may play an important role. In this study, we investigated the photochemical reactivity of A2E and its complex with bovine serum albumin (BSA) using UV-Vis absorption and emission spectroscopy, EPR-spin trapping, EPR-oximetry, time-resolved singlet oxygen phosphorescence, and the fluorogenic CBA probe. Our data show that A2E after complexation with this model protein photogenerated an increased level of ROS, particularly singlet oxygen. We also demonstrated the ability of A2E to oxidize BSA upon excitation with blue light in aqueous model systems. The data suggest that pyridinium bis-retinoid could oxidatively modify cellular proteins under physiological conditions.

背景与目标： : 双视黄醇N-视黄醇-N-亚视黄醇乙醇胺 (A2E) 是视网膜色素上皮 (RPE) 视觉循环的副产品。它有助于年龄色素脂褐素的金黄色荧光，该色素在RPE中积累。脂褐素在蓝光激发时可以产生多种活性氧 (ROS)。尽管在模型系统中，A2E的光反应活性已被确定为低，但这种双类维生素a在体外RPE细胞中表现出明显的光毒性。尽管A2E-mediated光毒性的机制仍然未知，但我们假设具有不同生物分子的A2E-adducts的形成可能起着重要作用。在这项研究中，我们使用UV-Vis吸收和发射光谱，EPR-自旋捕获，EPR-血氧饱和度，时间分辨单线态氧磷光和荧光CBA探针研究了A2E及其与牛血清白蛋白 (BSA) 的配合物的光化学反应性。我们的数据表明，与该模型蛋白复合后的A2E光产生的ROS水平增加，尤其是单线态氧。我们还证明了A2E在水性模型系统中用蓝光激发时氧化BSA的能力。数据表明，吡啶鎓双类维生素a可以在生理条件下氧化修饰细胞蛋白。

BACKGROUND & AIMS: :Chemically and biologically modified nanoparticles are increasingly considered as viable and multifunctional tools to be used in cancer theranostics. Herein, we demonstrate that coordination of alizarin blue black B (ABBB) to the TiO(2) nanoparticle surface enhances the resulting nanoparticles by (1) creating distinct fluorescence emission spectra that differentiate smaller TiO(2) nanoparticles from larger TiO(2) nanoparticle aggregates (both in vitro and intracellular) and (2) enhancing visible light activation of TiO(2) nanoparticles above previously described methods to induce in vitro and intracellular damage to DNA and other targets. ABBB-TiO(2) nanoparticles are characterized through sedimentation, spectral absorbance, and gel electrophoresis. The possible coordination modes of ABBB to the TiO(2) nanoparticle surface are modeled by computational methods. Fluorescence emission spectroscopy studies indicate that ABBB coordination on TiO(2) nanoparticles enables discernment between nanoparticles and nanoparticle aggregates both in vitro and intracellular through fluorescence confocal microscopy. Visible light activated ABBB-TiO(2) nanoparticles are capable of inflicting increased DNA cleavage through localized production of reactive oxygen species as visualized by plasmid DNA damage detected through gel electrophoresis and atomic force microscopy. Finally, visible light excited ABBB-TiO(2) nanoparticles are capable of inflicting damage upon HeLa (cervical cancer) cells by inducing alterations in DNA structure and membrane associated proteins. The multifunctional abilities of these ABBB-TiO(2) nanoparticles to visualize and monitor aggregation in real time, as well as inflict visible light triggered damage upon cancer targets will enhance the use of TiO(2) nanoparticles in cancer theranostics.

背景与目标： : 化学和生物修饰的纳米颗粒越来越被认为是用于癌症治疗的可行和多功能工具。在此，我们证明了茜素蓝黑B (ABBB) 与TiO(2) 纳米颗粒表面的配位通过 (1) 创建独特的荧光发射光谱，将较小的TiO(2) 纳米颗粒与较大的TiO(2) 纳米颗粒聚集体区分开来 (在体外和细胞内) 和 (2) 增强TiO(2) 纳米颗粒的可见光活化上述方法诱导体外和细胞内损伤DNA和其他靶标。ABBB-TiO(2) 纳米颗粒通过沉降，光谱吸光度和凝胶电泳进行表征。通过计算方法对ABBB与TiO(2) 纳米颗粒表面的可能协调模式进行了建模。荧光发射光谱研究表明，在TiO(2) 纳米颗粒上的ABBB配位能够通过荧光共聚焦显微镜在体外和细胞内识别纳米颗粒和纳米颗粒聚集体。可见光激活的ABBB-TiO(2) 纳米颗粒能够通过通过凝胶电泳和原子力显微镜检测到的质粒DNA损伤来观察，从而通过局部产生活性氧而导致DNA裂解增加。最后，可见光激发的ABBB-TiO(2) 纳米颗粒能够通过诱导DNA结构和膜相关蛋白的改变而对HeLa (宫颈癌) 细胞造成损害。这些ABBB-TiO(2) 纳米颗粒实时可视化和监测聚集以及对癌症靶标造成可见光触发损害的多功能能力将增强TiO(2) 纳米颗粒在癌症治疗中的应用。