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Selected AbstractsSynthesis of photosensitive and thermosetting poly(phenylene ether) based on poly[2,6-di(3-methyl-2-butenyl)phenol- co -2,6-dimethyl-phenol] and a photoacid generatorJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2005Kazuya Matsumoto Abstract A chemically amplified photosensitive and thermosetting polymer based on poly[2,6-di(3-methyl-2-butenyl)phenol (15 mol %)- co -2,6-dimethylphenol (85 mol %)] (3c) and a photoacid generator [(5-propylsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile] was developed. Poly[2,6-bis(3-methyl-2-butenyl)phenol]- co -2,6-dimethylphenol)] (3) with high molecular weights (number-average molecular weight , 24,000) was prepared by the oxidative coupling copolymerization of 2,6-di(3-methyl-2-butenyl)phenol with 2,6-dimethylphenol in the presence of copper(I) chloride and pyridine as the catalyst under a stream of oxygen. The structures of 3 were characterized with IR, 1H NMR, and 13C NMR spectroscopy. 3 was crosslinked by a thermal treatment at 300 °C for 1 h under N2. The 5% weight loss temperatures and glass-transition temperatures of the cured copolymers reached around 420 °C in nitrogen and 300 °C, respectively. The average refractive index of the cured copolymer (3c) film was 1.5452, from which the dielectric constant at 1 MHz was estimated to be 2.6. The resist showed a sensitivity of 35 mJ cm,2 and a contrast of 1.6 when it was exposed to 436-nm light, postexposure-baked at 145 °C for 5 min, and developed with toluene at 25 °C. A fine negative image featuring 8-,m line-and-space patterns was obtained on a film exposed to 100 mJ cm,2 with 436-nm light in the contact-printed mode. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 149,156, 2005 [source] Analysis of Compact Fluorescent Lights for Use by Patients with Photosensitive ConditionsPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2009Rachel S. Klein Ultraviolet radiation (UVR) is hazardous to patients with photosensitive skin disorders, such as lupus erythematosus, xeroderma pigmentosum and skin cancer. As such, these patients are advised to minimize their exposure to UVR. Classically, this is accomplished through careful avoidance of sun exposure and artificial tanning booths. Indoor light bulbs, however, are generally not considered to pose significant UVR hazard. We sought to test this notion by measuring the UV emissions of 19 different compact fluorescent light bulbs. The ability to induce skin damage was assessed with the CIE erythema action spectrum, ANSI S(,) generalized UV hazard spectrum and the CIE photocarcinogenesis action spectrum. The results indicate that there is a great deal of variation amongst different bulbs, even within the same class. Although the irradiance of any given bulb is low, the possible daily exposure time is rather lengthy. This results in potential daily UVR doses ranging from 0.1 to 625 mJ cm,2, including a daily UVB (290,320 nm) dose of 0.01 to 15 mJ cm,2. Because patients are exposed continually over long time frames, this could lead to significant cumulative damage. It would therefore be prudent for patients to use bulbs with the lowest UV irradiance. [source] Narrow-band UVB-induced Externalization of Selected Nuclear Antigens in Keratinocytes: Implications for Lupus Erythematosus Pathogenesis,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2009Adam Reich The aim of this study was to analyze whether sera obtained from patients with lupus erythematosus (LE) react with membrane structures found on keratinocytes irradiated with narrow-band ultraviolet B (NB-UVB). We applied atomic force microscopy (AFM) to visualize cell surface structures expressing nuclear antigens upon apoptosis following NB-UVB irradiation. Immortalized human keratinocytes (HaCaT) were cultured under standard conditions, irradiated with 800 mJ cm,2 NB-UVB light and imaged by AFM mounted on an inverted optical microscope. It was observed that NB-UVB irradiation provoked significant alterations of the keratinocyte morphology and led to the membrane expression of antigens recognized by anti-La and anti-Ro 60 kDa sera but not by antidouble-strand DNA sera. The presence of La and Ro 60 kDa antigens on keratinocyte surfaces after NB-UVB irradiation was limited mainly to the small bleb-like protrusions found on the keratinocytes by AFM. A closer investigation by AFM also revealed that some structures positively stained with anti-Ro 60 kDa serum were also located submembranously. We hypothesize that the externalization of some nuclear antigens because of NB-UVB exposure might be responsible for exacerbation of skin symptoms in patients suffering from LE. [source] Time-course Expression of DNA Repair-related Genes in Hepatocytes of Zebrafish (Danio rerio) After UV-B ExposurePHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2009Juliana Z. Sandrini The objective of this study was to evaluate the time-course effects of UV-B exposure on expression of genes involved in the DNA repair system of zebrafish (Danio rerio) hepatocytes, a highly competent species in terms of damage repair induced by UV radiation. For gene expression analysis (RT-PCR), cells were exposed to 23.3 mJ cm,2 UV-B, which was the dose that affected viable cell number (reduction of 30% when compared with the control group) and produced no visual alteration on cell morphology. The early response observed (6 h) showed induction in the expression of the CDKI gene (cyclin-dependent kinase inhibitor) and genes related to DNA damage repair (mainly XPC and DDB2), while the late response observed (24 h) was more related to up-regulation of p53 and genes involved in cell cycle arrest (gadd45a, cyclinG1). In all times analyzed, the anti-apoptotic gene Bcl-2 was down-regulated. Another interesting result observed was the up-regulation of the Apex- 1 gene after UV-B exposure, which could indicate the induction of oxidative lesions in the DNA molecule. In conclusion, these results demonstrate an activation of the DNA repair system in hepatocytes of zebrafish exposed to UV-B radiation, mainly involving the participation of p53. [source] Inhibition of UVB-mediated Oxidative Stress and Markers of Photoaging in Immortalized HaCaT Keratinocytes by Pomegranate Polyphenol Extract POMxPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2007Mohammad Abu Zaid In recent years there has been an increase in use of botanicals with antioxidant properties as skin photoprotective agents. Pomegranate (Punica granatum L.) fruit possesses strong antioxidant and antiinflammatory properties. Recently, we have shown that pomegranate-derived products rich in anthocyanidins and ellagitannins inhibit UVB-mediated activation of nuclear factor kappa B and modulate UVA-mediated cell proliferation pathways in normal human epidermal keratinocytes. In this study, we evaluated the effect of polyphenol-rich pomegranate fruit extract (POMx) on UVB-induced oxidative stress and photoaging in human immortalized HaCaT keratinocytes. Our data show that pretreatment of HaCaT cells with POMx (10,40 ,g mL,1) inhibited UVB (15,30 mJ cm,2)-mediated (1) decrease in cell viability, (2) decrease in intracellular glutathione content and (3) increase in lipid peroxidation. Employing immunoblot analysis we found that pretreatment of HaCaT cells with POMx inhibited UVB-induced (1) upregulation of MMP-1, -2, -7 and -9, (2) decrease in TIMP-1, (3) phosphorylation of MAPKs and (iv) phosphorylation of c-jun, whereas no effect was observed on UVB-induced c-fos protein levels. These results suggest that POMx protects HaCaT cells against UVB-induced oxidative stress and markers of photoaging and could be a useful supplement in skin care products. [source] Unusual High Exposure to Ultraviolet-C RadiationPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2006Andrea Trevisan ABSTRACT ?1 UV radiation is known to cause acute and chronic eye and skin damage. The present case report describes a 90 min accidental exposure to UV-C radiation of 26 medical school students. Germicidal lamps were lit due to a malfunctioning of the timer system. Several hours after irradiation exposure, all subjects reported the onset of ocular symptoms, subsequently diagnosed as photokeratitis, and skin damage to the face, scalp and neck. While the ocular symptoms lasted 2,4 days, the sunburn-like condition produced significant erythema followed by deep skin exfoliation. The irradiation was calculated to be approximately 700 mJ cm,2 absorbed energy, whereas the actual radiation emitted by the lamps was 0.14 mW cm,2 (the radiometric measurements confirmed these calculi, because the effective irradiance measured from the height of the autopsy table to about 1 m under the UV-C lamp varied from 0.05 to 0.25 mW cm,2) but, more likely, the effective irradiance, according to skin phototype and symptoms, was between 50 and 100 mJ cm,2. The ocular and skin effects produced by such a high irradiation (largely higher than that accepted by the American Conference of Governmental Industrial Hygienists [ACGIH] threshold limit values [TLVs]) appeared reversible in a relatively short time. [source] Surface topography and surface chemistry of radiation-patterned P(tBuMA),analysis by atomic force microscopyPOLYMER INTERNATIONAL, Issue 9 2003Gregory S Watson Abstract Poly-(tert -butyl methacrylate) (P(tBuMA)) thin-film surfaces were patterned by UV radiation at doses in the range 10,100 mJ cm,2, in order to induce laterally differentiated surface chemistry with µm resolution. The most likely pathway for the radiation chemistry predicts a transition from hydrophobicity to hydrophilicity. Outcomes of analysis by atomic force microscopy under air ambient conditions were consistent with that prediction. Topographic and lateral force imaging, in combination with friction loop analysis, revealed shrinkage and increased friction arising from exposure. Force versus distance analysis revealed greater adhesion in hydrophilic regions, due to greater meniscus force acting on the tip. The thickness of adsorbed moisture, increased by a factor of 2.5 from ca 0.8 nm for the unirradiated surface, as a result of greater hydrophilicity induced by radiation. The latter observation shows that the increased friction was due principally to the greater normal force on the tip from an additional meniscus force. Copyright © 2003 Society of Chemical Industry [source] Artificial gynogenesis in Cynoglossus semilaevis with homologous sperm and its verification using microsatellite markersAQUACULTURE RESEARCH, Issue 6 2010Xiang-Shan Ji Abstract Effective methods for induction of gynogenetic diploids in Cynoglossus semilaevis are needed to initiate monosex culture. An effective protocol to induce half-smooth tongue sole gynogenesis using homologous sperm was developed in this study. A UV dose of 50 mJ cm,2 was found to be the most effective for genetic inactivation of tongue sole sperm. Treatment optima for cold shocks were 5 °C for 20,23 min at 5 min after fertilization and the hatching rate of gynogenetic diploids was 10.0%. Microsatellite analysis at locus Csou 6 revealed that there was no genetic contribution from the paternal genome in 24 progenies of a meiotic gynogenetic family. Polymerase chain reaction demonstrated that only four individuals of 24 meiotic gynogenetic diploids produced the female-specific band of about 205 bp. The female/male ratio of gynogenetic diploids was significantly different from the theoretical ratio of 1:1. It is possible that there are some recessive lethal genes in W chromosome. [source] Nuclear transfer in loach (Paramisgurnus dabryanus Sauvage) by cell-to-cell electrofusionAQUACULTURE RESEARCH, Issue 4 2001F Hongtuo Abstract To study nuclear transfer in the loach (Paramisgurnus dabryanus Sauvage), blastula and gastrula cells were fused with UV-inactivated oocytes by cell-to-cell electrofusion. To facilitate nuclear transfer, blastula and gastrula cells were cultured or incubated at 4 °C in different solutions. TC-199 medium supplemented with 20% calf serum was the best culture solution, and effectively retained the totipotence of blastula or gastrula cells for up to 10 days. It was found that gastrula cells incubated at 4 °C had the same totipotence as blastula cells. The optimal UV dosage for inactivation of the oocyte chromatin was 180,240 mJ cm,2. Electrofusion was carried out in a cone-shaped fusion chamber, which permitted the recipient oocyte and the donor blastula cell to contact one another. The electrofusion procedure resulted in a 10% success rate of normal-appearing fish. Genetic analysis indicated that the nuclear material originated from the donor cell (blastomere) and the oocyte pronucleus did not take part in development. [source] Effect of ultraviolet (UV) A, UVB or ionizing radiation on the cell cycle of human melanoma cellsBRITISH JOURNAL OF DERMATOLOGY, Issue 5 2007M. Placzek Summary Background, One important component of the cellular response to irradiation is the activation of cell cycle checkpoints. It is known that both ultraviolet (UV) radiation and ionizing radiation (IR) can activate checkpoints at transitions from G1 to S phase, from G2 phase to mitosis and during DNA replication. Objectives, To evaluate the effects of irradiation with different wavelengths on cell cycle alterations. Methods, p53-deficient IPC-298 melanoma cells were irradiated with 10 J cm,2 UVA, 40 mJ cm,2 UVB, or with 7·5 Gy IR. Cell cycle effects were then determined by DNA/5-bromodeoxyuridine dual-parameter flow cytometry. Results, IPC-298 cells irradiated in G1 with UVA were not arrested at the G1/S transition, but at the G2/M transition. Despite p53 deficiency, the cells showed a G1 arrest after UVB exposure. Furthermore, IR did not affect G1 or S phase, but induced G2 phase arrest. Hence, the effects of UVA, but not of UVB, on the cell cycle in p53-deficient melanoma cells are comparable with those of IR. Conclusions, UVA and IR induce radical-mediated strand breaks and DNA lesions, and UVB essentially induces thymine dimers that lead to excision repair-related strand breaks. Different cell cycle effects may be a consequence of different types of DNA damage. The results showed that UVB-irradiated p53-deficient cells are arrested in G1. Irradiation with the solar radiation component UVB can therefore result in a beneficial retardation of tumour promotion in human skin carrying p53-mutated cell clones. [source] The photocarcinogenic risk of narrowband UVB (TL-01) phototherapy: early follow-up dataBRITISH JOURNAL OF DERMATOLOGY, Issue 4 2005I. Man Summary Background, Limited information is available on the carcinogenic risk associated with narrowband TL-01 UVB phototherapy in humans. Objectives, To determine the skin cancer incidence in a population treated with TL-01 phototherapy. Patients and methods, All TL-01-treated patients were identified from the departmental computerized database. Patients with malignant melanoma (MM), squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) were identified by record linkage with the Scottish Cancer Registry. The incidence of each was compared with the normal Scottish population matched for age and sex. Results, Data were obtained from 1908 patients. The median follow-up duration was 4 years (range 0·04,13). The median cumulative number of TL-01 treatments and dose were 23 (1,199) and 13 337 (30,284 415) mJ cm,2, respectively. No increased incidence of SCC or MM was observed. Ten patients developed BCC compared with an expected 4·7 in the Scottish population [standardized rate ratio 213 (95% confidence interval 102,391); P < 0·05]. Conclusions, A small but significant increase of BCC was detected in the TL-01 group. This could be explained by a number of factors, including ascertainment bias. To determine the true carcinogenic risk of TL-01 phototherapy, longer follow-up is essential. [source] | ||||||||||