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Exposure Dose (exposure + dose)
Selected AbstractsSoft-Contact Optical Lithography Using Transparent Elastomeric Stamps and Application to Nanopatterned Organic Light-Emitting DevicesADVANCED FUNCTIONAL MATERIALS, Issue 9 2005T.-W. Lee Abstract Conventional photolithography uses rigid photomasks of fused quartz and high-purity silica glass plates covered with patterned microstructures of an opaque material. We introduce new, transparent, elastomeric molds (or stamps) of poly(dimethylsiloxane) (PDMS) that can be employed as photomasks to produce the same resist pattern as the pattern of the recessed (or non-contact) regions of the stamps, in contrast to other reports in the literature[1] of using PDMS masks to generate edge patterns. The exposure dose of the non-contact regions with the photoresist through the PDMS is lower than that of the contact regions. Therefore, we employ a difference in the effective exposure dose between the contact and the non-contact regions through the PDMS stamp to generate the same pattern as the PDMS photomask. The photomasking capability of the PDMS stamps, which is similar to rigid photomasks in conventional photolithography, widens the application boundaries of soft-contact optical lithography and makes the photolithography process and equipment very simple. This soft-contact optical lithography process can be widely used to perform photolithography on flexible substrates, avoiding metal or resist cracks, as it uses soft, conformable, intimate contact with the photoresist without any external pressure. To this end, we demonstrate soft-contact optical lithography on a gold-coated PDMS substrate and utilized the patterned Au/PDMS substrate with feature sizes into the nanometer regime as a top electrode in organic light-emitting diodes that are formed by soft-contact lamination. [source] Characterization of parylene-N and parylene-C photooxidationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 10 2003K. G. Pruden Abstract Parylene-N and parylene-C are polymers of interest for microelectronic and medical coating applications. Modifications for improved surface properties could make them even more useful in such applications. Parylene-N and parylene-C films were exposed to ultraviolet light in the presence of oxygen and analyzed with Rutherford backscattering spectrometry, secondary-ion mass spectroscopy, X-ray photoelectron spectroscopy, and infrared spectroscopy. This study shows that such exposure results in the formation of aldehyde and carboxylic acid groups near the surface of the films. At the maximum exposure dose, the concentration of oxygen in both parylene-N and parylene-C is about 13% at the film surface, and it decreases exponentially with increasing depth. Further modeling and optimization of this process would allow it to be used to tailor the surface concentration of oxygenated species in parylene for the optimization of adhesion and wettability or for the chemical binding of other moieties. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1486,1496, 2003 [source] Analgesic use and the risk for progression of chronic kidney disease,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 7 2010Hsin-Wei Kuo Abstract Purpose The chronic effect of various analgesics on the progression of chronic kidney disease (CKD) is inconclusive. There is also lack of information on the renal safety of selective cyclooxygenase-2 (COX-2) inhibitors. This study aimed to clarify the renal risk of analgesic use in CKD patients. Methods A cohort study using a nationally representative database randomly sampled from National Health Insurance (NHI) enrollees was performed. The study population included a total of 19,163 newly diagnosed CKD patients. Clinical conditions were defined by diagnostic codes and exposure information on analgesics was derived from service claims. Cox proportional hazard model was used to assess the association between analgesic use and the risk of progression to end stage renal disease (ESRD). Results CKD patients using acetaminophen, aspirin, and non-selective non-steroidal anti-inflammatory drugs (NSAIDs) had an increased risk for ESRD with multivariable-adjusted HRs (95%CIs) of 2.92 (2.47,3.45), 1.96 (1.62,2.36), and 1.56 (1.32,1.85), respectively. The trends toward higher risk with increasing exposure dose were significant for all classes of analgesics (all P for trend,<,0.001). Among COX-2 inhibitors, only rofecoxib, but not celecoxib, shows a significant risk association with ESRD (HR,=,1.98; 95%CI, 1.15,3.40). Conclusions Our data indicated exacerbating effects of acetaminophen, aspirin, and non-selective NSAIDs on CKD in a dose-dependent manner. For COX-2 inhibitors, only rofecoxib showed an increased risk for ESRD. Although the possibility of residual confounding cannot be completely ruled out, given the common use of analgesics, the possible relation suggested by this study warrants further investigation. Copyright © 2010 John Wiley & Sons, Ltd. [source] WST11, A Novel Water-soluble Bacteriochlorophyll Derivative; Cellular Uptake, Pharmacokinetics, Biodistribution and Vascular-targeted Photodynamic Activity Using Melanoma Tumors as a Model,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2005Ohad Mazor ABSTRACT WST11 is a novel negatively charged water-soluble palladiumbacteriochlorophyll derivative that was developed for vascular-targeted photodynamic therapy (VTP) in our laboratory. The in vitro results suggest that WST11 cellular uptake, clearance and phototoxicity are mediated by serum albumin trafficking. In vivo, WST11 was found to clear rapidly from the circulation (t1/2= 1.65 min) after intravenous bolus injection in the mouse, whereas a longer clearance time (t1/2= 7.5 min) was noted in rats after 20 min of infusion. The biodistribution of WST11 in mouse tissues indicates hepatic clearance (t1/2= 20 min), with minor (kidney, lung and spleen) or no intermediary accumulation in other tissues. As soon as 1 h after injection, WST11 had nearly cleared from the body of the mouse, except for a temporal accumulation in the lungs from which it cleared within 40 min. On the basis of these results, we set the VTP protocol for a short illumination period (5 min), delivered immediately after WST11 injection. On subjecting M2R melanoma xenografts to WST11-VTP, we achieved 100% tumor flattening at all doses and a 70% cure with 9 mg/kg and a light exposure dose of 100 mW/cm2. These results provide direct evidence that WST11 is an effective agent for VTP and provide guidelines for further development of new candidates. [source] Solar UVR exposures of indoor workers in a Working and a Holiday Period assessed by personal dosimeters and sun exposure diariesPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 6 2001E. Thieden Background/Aim: The aim of this study was to quantify ultraviolet radiation (UVR) exposure of fully employed indoor workers during a Working Period and a Holiday Period in the summer months. A further aim was to investigate the correlation between individual personal UVR dosimeter reading and self-reported data in a diary about sun exposure habits and to investigate whether skin type, age and gender influence sun exposure. Methods: The solar UVR, in standard erythema doses (SED) measured by UV sensitive spore-film filter type personal dosimeters (VioSpor®), and sun exposure diaries were compared. The study included 44 healthy Danish adult indoor workers during a Working Period of a mean of 13 days and a Holiday Period of a mean of 17 days from June to September. Results: The individual total UVR exposure correlated significantly (P<0.001) in both the Holiday and Working Periods with individual total hours spent outdoors from 07:00 to 19:00 and with skin area exposure hours. There was no significant correlation between sun exposure dose and gender, age or skin type I-IV, or between the individual solar exposure dose in the Working and the Holiday Period. However, subjects with UVR exposures in the upper quartile spent their Holiday Period in Southern Europe, and/or had been more than the mean time outdoors at the beach/sea and/or between 12:00 and 15:00. Subjects with UVR exposure in the lower quartiles spent their holidays in Denmark or Northern Europe and did not stay at the beach at all. They received an average solar UVR dose which was 22% of ambient in Denmark in the same period while subjects having their holidays in Southern Europe received as much as 90% of the ambient dose in Denmark. Conclusions: Despite information campaigns to avoid the midday sun, on average 35% of the recorded hours outdoors were spent between 12:00 and 15:00 in the Holiday Period. Total hours outdoors give the best estimate of the total sun exposure dose. Registration in a diary of total hours outdoors and whether the Holiday Period was in Northern or Southern Europe can be used to predict the solar exposure dose in a Holiday Period of a few weeks. [source] Synthesis and characterization of novel photosensitive polyimide based on 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydridePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 1 2005Eun Young Chung Abstract A negative type photosensitive polyimide with alicyclic moiety (NPI) was synthesized from 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride and 4,4-diaminobenzophenone by one-step polymerization in m -cresol. Properties of the polyimides were characterized and a photo-crosslinking mechanism was investigated using DEPT 13C-NMR and FT-IR spectroscopy. The negative polyimide showed good photosensitivity on exposure to UV light from a mercury xenon lamp. The polyimide showed remarkable solubility difference after photo- irradiation with an exposure dose of 500,mJ/cm2. The resulting negative pattern of the photo-cured NPI exhibited 10,,m resolution. Glass transition temperature of the photo-crosslinked polyimide was about 307°C, which increased by 10°C compared to that of the polyimide before UV exposure. Transmittance of NPI after photo-irradiation was about 87% at 500,nm. Copyright © 2004 John Wiley & Sons, Ltd. [source] Better data needed from pregnancy registries,BIRTH DEFECTS RESEARCH, Issue 2 2009Gerald G. Briggs Abstract This article is a consensus position statement from the Research Committee of the Organization of Teratology Information Specialists (OTIS). The Committee believes that more specific information on the timing and dose of drug exposures from pregnancy birth defect registries sponsored by pharmaceutical companies (herein called pregnancy registries) would improve the estimation of risk for developmental toxicity (i.e., growth alteration, structural anomalies, functional/neurobehavioral deficits, or death). Specifically, the Committee believes that the exposure timing should be stated in gestational weeks and days rather than simply weeks. In addition, the Committee believes that the exposure dose should be stated in patient-specific terms, such as body weight (mg/kg) or body surface area (mg/m2) rather than simply dose strength. Although the focus of this position is pregnancy registries, it also is applicable to any source of medication-induced embryo-fetal toxicity. Birth Defects Research (Part A), 2009. © 2008 Wiley-Liss, Inc. [source] Evaluation of the radioprotective effect of Ageratum conyzoides Linn. extract in mice exposed to different doses of gamma radiationJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 8 2003Ganesh Chandra Jagetia The effect of various doses (0, 25, 50, 75, 100, 125, 150, 300, 600 and 900 mg kg,1) of the alcoholic extract of the plant Ageratum conyzoides Linn. (ACE), on the alteration of radiation-induced mortality in mice exposed to 10 Gy of gamma radiation was studied. The acute toxicity studies showed that the drug was non-toxic up to a dose of 3000 mg kg,1, the highest dose that could be tested for acute toxicity. Administration of ACE resulted in a dose-dependent decline in radiation-induced mortality up to a dose of 75 mg kg,1, the dose at which the highest number of survivors (70.83%) was observed. Thereafter, the number of survivors declined with increasing doses of ACE and a nadir was reached at 900 mg kg,1 ACE. Since the number of survivors was highest for 75 mg kg,1 ACE, this was considered the optimum dose for radioprotection and used in further studies in which mice were treated with 75 mg kg,1 ACE before exposure to 6, 7, 8, 9, 10 and 11 Gy of gamma radiation. The treatment of mice with 75 mg kg,1 ACE reduced the severity of symptoms of radiation sickness and mortality at all exposure doses, and a significant increase in survival was observed compared with the non-treated irradiated group. The ACE treatment effectively protected mice against the gastrointestinal as well as bone marrow related death, as revealed by the increased number of survivors at all irradiation doses. The dose reduction factor was found to be 1.3. To understand the mechanism of action, various doses of ACE were evaluated for their in-vitro scavenging action on 1,1-diphenyl-2-picrylhydrazyl (DPPH), a chemically stable free radical. ACE was found to scavenge DPPH radicals in a concentration-dependent manner, indicating that the radioprotection afforded by ACE may be in part due to the scavenging of reactive oxygen species induced by ionizing radiation. [source] Parental exposure to lead and small for gestational age birthsAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 6 2006Pau-Chung Chen MD Abstract Background Previous studies about the effect of lead exposure on adverse birth outcomes are still inconsistent and few studies estimate the relationship between parental lead exposure and small for gestational age (SGA) infants. An occupational cohort study to assess whether parental lead exposure would be related to decreased birth weight and shortened gestational ages of their offspring was conducted. Whether higher lead exposure doses would increase risks of low birth weight (LBW), preterm delivery, and SGA births was also investigated. Methods A Program to Reduce Exposure by Surveillance System,Blood Lead Levels (Press-BLLS) was established in Taiwan in July 1993. The names of workers exposed to lead was collected from this occupational blood-lead notification database. The birth outcomes of their offspring were determined by linking to the Taiwan birth registration database from 1993 to 1997. Only singleton births whose parental blood-lead concentrations were tested during pregnancy or prior to conception, or within a 1-year span before these two periods were included. Results Among 1,611 eligible births, 72 births were LBW, 74 were preterm deliveries, and 135 were SGA. Maternal blood-lead concentrations (PbBs) equal to or more than 20 µg/dl had a higher risk of mothering a SGA child (risk ratio (RR),=,2.15; 95% confidence interval (CI), 1.15,3.83). Conclusions Additional evidence of the effects of lead on adverse birth outcomes, especially for SGA births is reported. Maternal exposure to lead plays a more important role in the adverse effect on birth outcome than does paternal exposure. Am. J. Ind. Med. 2006. © 2006 Wiley-Liss, Inc. [source] | ||||||||||||||||