The effects of cyclodextrins (-CD,-CD and-CD) on the photobleaching of coumarin 120 (7-amino-4-methylcoumarin) (1) and coumarin 151 (7-amino-4-trifluoromethylcoumarin) (2) have been investigated by spectrophotometric measurement. It is concluded that-CD and-CD decelerate the rates of photobleaching of1, whilst-CD accelerates the rate of2 and-CD has no effect on the rate of photobleaching of2. 相似文献
The drainage and stability of DMPG (l-α-phosphatidyl-dl-glycerol dimyristoyl) foams were studied by a microconductivity method under conditions where three different foam film types could be formed—thin foam films (TFF), common black foam films (CBF), and Newton black foam films (NBF). Foaming properties were investigated at 20 and 28°C where DMPG is in the gel and liquid-crystalline states. Higher conductivity signals were observed at the higher temperature where DMPG was in the liquid-crystalline state, which is indicative of wetter or more stable foams under these conditions. This effect was observed independent of foam film type. However, for a given phase state, the type of foam films formed significantly influenced the stability and rate of drainage of the foam. Indeed, the water content of the foams, obtained under conditions for formation of different foam films, is ranked in the order TFF > CBF > NBF. When the temperature was increased to 28°C (i.e., in the liquid-crystalline state), CBF and NBF showed a slight decrease in film thickness and an increase in film lifetime and surface molecular diffusion coefficient in the adsorbed layer. It is likely that the fluidity of the interfacial layer is an important factor contributing to DMPG foam stabilization. 相似文献
Summary: Photobleachable deep UV resists were designed by introducing diazoketo groups in polymer side chains. The diazoketo groups undergo the Wolff rearrangement upon irradiation in the deep UV, affording ketenes that react with water to provide base‐soluble photoproducts. The polymers were synthesized by radical copolymerization of 2‐(2‐diazo‐3‐oxo‐butyryloxy)‐ethyl methacrylate, 2‐hydroxyethyl methacrylate, and γ‐butyrolacton‐2‐yl methacrylate. The single component resist showed 0.7 µm line and space patterns using a mercury‐xenon lamp in a contact printing mode.
Scanning electron micrograph of 0.7 µm line and space patterns printed with polymer B at a dose of 70 mJ · cm−2. 相似文献
Photoproducts formation upon irradiation (739 nm) of 5,10,15,20-tetrakis(m-hydroxyphenyl)bacteriochlorin (m-THPBC) in phosphate buffer saline (PBS) supplemented with human serum albumin (HSA) were studied by means of absorption spectroscopy and MALDI-TOF mass spectrometry. The experiments were performed with a freshly prepared PBS-HSA solution of m-THPBC and with a PBS-HSA m-THPBC solution incubated for 6 h at 37 degrees C. The incubation of m-THPBC solution leads to the dye monomerisation, whereas in the freshly prepared solution, m-THPBC is under an aggregated form. Regardless of the incubation condition, photobleaching experiments carried out by absorption spectroscopy demonstrate the degradation of the photosensitizer and its phototransformation in m-THPC. Moreover, m-THPC was the sole photoproduct detected using absorption spectroscopy. Together with a degradation of m-THPBC and formation of m-THPC, MALDI-TOF mass spectrometry evidenced several other photoinduced modifications. Photoproducts such as dihydroxy m-THPBC and dihydroxy m-THPC were detected in both conditions; however, the formation of hydroxylated photoproducts was significantly greater in incubated solution. In addition, small molecules arising from the degradation of the photosensitizer and identified as dipyrin derivatives and dipyrrolic synthon were observed. 相似文献
Regional differences in lateral diffusion rates of fluorescence-labeled proteins have been studied in the plasma membrane of dividing eggs of the loach (Misgurnus fossilis) by fluorescence recovery after photobleaching (FRAP). Apparent animal-vegetal differences in fluorescence intensity, lateral diffusion coefficients, and fractions of mobile proteins have been found, with all these quantities being higher in the animal pole region than in the yolk region. Cyclic changes in protein diffusion coefficients and mobile fractions during the first few cell cycles have also been recorded. Soon after the end of a cleavage, the diffusion coefficient reaches its minimal value and increases rapidly before the next cleavage. 相似文献