Home About us Contact
|
Home About us Contact | ||
|
|
||
Light Units (light + unit)
Selected AbstractsDiscovery of New Green Phosphors and Minimization of Experimental Inconsistency Using a Multi-Objective Genetic Algorithm-Assisted Combinatorial MethodADVANCED FUNCTIONAL MATERIALS, Issue 11 2009Asish Kumar Sharma Abstract A multi-objective genetic algorithm-assisted combinatorial materials search (MOGACMS) strategy was employed to develop a new green phosphor for use in a cold cathode fluorescent lamp (CCFL) for a back light unit (BLU) in liquid crystal display (LCD) applications. MOGACMS is a method for the systematic control of experimental inconsistency, which is one of the most troublesome and difficult problems in high-throughput combinatorial experiments. Experimental inconsistency is a very serious problem faced by all scientists in the field of combinatorial materials science. For this study, experimental inconsistency and material property were selected as dual objective functions that were simultaneously optimized. Specifically, in an attempt to search for promising phosphors with high reproducibility, luminance was maximized and experimental inconsistency was minimized using the MOGACMS strategy. A divalent manganese-doped alkali alkaline germanium oxide system was screened using MOGACMS. As a result of MOGA reiteration, we identified a phosphor, Na2MgGeO4:Mn2+, with improved luminance and reliable reproducibility. [source] Effect of light source and time on the polymerization of resin cement through ceramic veneersJOURNAL OF PROSTHODONTICS, Issue 3 2001Flavio H. Rasetto Odont Purpose The purpose of this study was to evaluate the efficiency of 3 different light sources to polymerize a light curing resin cement beneath 3 types of porcelain veneer materials. Materials and Methods A conventional halogen light, a plasma arc light, and a high intensity halogen light were used to polymerize resin cement (Variolink II; Ivoclar North America Inc, Amherst, NY) through disks of veneer materials. Equal diameter and thickness disks of feldspathic porcelain (Ceramco II; Ceramco Inc, Burlington, NJ), pressable ceramic (IPS Empress; Ivoclar North America Inc), and aluminous porcelain (Vitadur Alpha; Vident Inc, Brea, CA) were used as an interface between the curing light tips and the light polymerized resin cement. The resin cement/veneer combinations were exposed to 4 different photopolymerization time protocols of 5 seconds, 10 seconds, 15 seconds, and 20 seconds for high intensity light units (Apollo 95E [Dental Medical Diagnostic Systems Inc, Westlake Village, CA] and Kreativ 2000 [Kreativ Inc, San Diego, CA]), and 20 seconds, 40 seconds, 60 seconds, and 80 seconds for conventional halogen light (Optilux; Demetron Research Inc, Danbury, CT). A surface hardness test (Knoop indenter) was used to determine the level of photopolymerization of the resin through the ceramic materials with each of the light sources. The data were analyzed by one-way analysis of variance and a post-hoc Scheffe test (p < .05). Results The data indicates that the Variolink II Knoop Hardness Number values vary with the light source, the veneer material, and the polymerization time. For a given light and veneer material, Knoop Hardness Number increases with longer polymerization times. The Kreativ light showed statistically significant differences (p < .05) between all test polymerization times. Use of this light required a polymerization time of greater than 20 seconds to reach maximum resin cement hardness. For samples polymerized with the Apollo light, there were statistically significant (p < .05) differences in surface hardness between samples polymerized at all times, except for the 15-second and 20-second times. Samples polymerized with the halogen light showed no statistically significant (p < .05) differences in hardness between polymerization times of 60 seconds and 80 seconds. Conclusions High intensity curing lights achieve adequate polymerization of resin cements through veneers in a markedly shorter time period than the conventional halogen light. However, the data in this report indicate that a minimum exposure time of 15 seconds with the Kreativ light and 10 seconds with the Apollo 95E light should be used to polymerize the Variolink II resin, regardless of the composition of the veneer. Conventional halogen lights required a correspondingly greater polymerization time of 60 seconds. [source] In vivo electroporation and ubiquitin promoter , a protocol for sustained gene expression in the lungTHE JOURNAL OF GENE MEDICINE, Issue 7 2006Amiq Gazdhar Abstract Background Gene therapy applications require safe and efficient methods for gene transfer. Present methods are restricted by low efficiency and short duration of transgene expression. In vivo electroporation, a physical method of gene transfer, has evolved as an efficient method in recent years. We present a protocol involving electroporation combined with a long-acting promoter system for gene transfer to the lung. Methods The study was designed to evaluate electroporation-mediated gene transfer to the lung and to analyze a promoter system that allows prolonged transgene expression. A volume of 250 µl of purified plasmid DNA suspended in water was instilled into the left lung of anesthetized rats, followed by left thoracotomy and electroporation of the exposed left lung. Plasmids pCiKlux and pUblux expressing luciferase under the control of the cytomegalovirus immediate-early promoter/enhancer (CMV-IEPE) or human polyubiquitin c (Ubc) promoter were used. Electroporation conditions were optimized with four pulses (200 V/cm, 20 ms at 1 Hz) using flat plate electrodes. The animals were sacrificed at different time points up to day 40, after gene transfer. Gene expression was detected and quantified by bioluminescent reporter imaging (BLI) and relative light units per milligram of protein (RLU/mg) was measured by luminometer for p.Pyralis luciferase and immunohistochemistry, using an anti-luciferase antibody. Results Gene expression with the CMV-IEPE promoter was highest 24 h after gene transfer (2932 ± 249.4 relative light units (RLU)/mg of total lung protein) and returned to baseline by day 3 (382 ± 318 RLU/mg of total lung protein); at day 5 no expression was detected, whereas gene expression under the Ubc promoter was detected up to day 40 (1989 ± 710 RLU/mg of total lung protein) with a peak at day 20 (2821 ± 2092 RLU/mg of total lung protein). Arterial blood gas (PaO2), histological assessment and cytokine measurements showed no significant toxicity neither at day 1 nor at day 40. Conclusions These results provide evidence that in vivo electroporation is a safe and effective tool for non-viral gene delivery to the lungs. If this method is used in combination with a long-acting promoter system, sustained transgene expression can be achieved. Copyright © 2006 John Wiley & Sons, Ltd. [source] Enhancing rAAV vector expression in the lungTHE JOURNAL OF GENE MEDICINE, Issue 7 2005Isabel Virella-Lowell Abstract Despite favorable DNA transfer efficiency, gene expression from recombinant adeno-associated virus (rAAV2) vectors in the lung has been variable in the context of cystic fibrosis (CF) gene therapy. This is due, in part, to the large size of the CF transmembrane regulator (CFTR)-coding sequence which necessitates the use of compact endogenous promoter elements versus stronger exogenous promoters. We evaluated the possibility that gene expression from rAAV could be improved by using AAV capsid serotypes with greater tropism for the apical surface of airway cells (i.e. rAAV5 or rAAV1) and/or using strong promoters such as the cytomegalovirus (CMV) enhancer/chicken beta-actin hybrid (C,) promoter. The relative activity of the CMV immediate-early (CMVie) promoter, the C, promoter, and the C, promoter with a downstream woodchuck hepatitis virus post-transcriptional regulatory element (wpre) were assessed in vitro and in vivo in C57\Bl6 mice using human alpha-1 antitrypsin (hAAT) as a secreted reporter. In vivo, the C,-AAT-wpre group achieved maximum serum levels of 1.5 mg/ml of hAAT. AAV capsid serotypes were then compared in vivo utilizing the transcriptionally optimized CB-wpre cassette in rAAV serotype 1, 2 or 5 capsids (rAAV1, rAAV2, and rAAV5), utilizing luciferase as a reporter to compare expression over a wide dynamic range. The pulmonary luciferase levels at 8 weeks were similar in rAAV5 and rAAV1 groups (2.9 × 106 relative light units (RLU)/g tissue and 2.7 × 106 RLU/g tissue, respectively), both of which were much higher than rAAV2. Although the advantage of rAAV5 over rAAV2 in the lung has already been described, the availability of another serotype (rAAV1) capable of efficient gene transfer in the lung could be useful. Copyright © 2005 John Wiley & Sons, Ltd. [source] An efficient gene transfer method mediated by ultrasound and microbubbles into the kidneyTHE JOURNAL OF GENE MEDICINE, Issue 1 2005Hiromi Koike Abstract Background Safety issues are of paramount importance in clinical human gene therapy. From this point of view, it would be better to develop a novel non-viral efficient gene transfer method. Recently, it was reported that ultrasound exposure could induce cell membrane permeabilization and enhance gene expression. Methods In this study, we examined the potential of ultrasound for gene transfer into the kidney. First, we transfected rat left kidney with luciferase plasmid mixed with microbubbles, Optison, to optimize the conditions (duration of ultrasound and concentration of Optison). Then, 4, 7, 14 and 21 days after gene transfer, luciferase activity was measured. Next, localization of gene expression was assessed by measuring luciferase activity and green fluorescent protein (GFP) expression. Expression of GFP plasmid was examined under a fluorescence microscope at 4 and 14 days after gene transfer. Finally, to examine the side effects of this gene transfer method, biochemical assays for aspartate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen (BUN) and creatinine (Cre) were performed. Results Optison and/or ultrasound significantly enhanced the efficiency of gene transfer and expression in the kidney. Especially, 70,80% of total glomeruli could be transfected. Also, a significant dose-dependent effect of Optison was observed as assessed by luciferase assay (Optison 25%: 12.5 × 105 relative light units (RLU)/g tissue; 50%: 31.3 × 105 RLU/g tissue; 100%: 57.9 × 105 RLU/g tissue). GFP expression could be observed in glomeruli, tubules and interstitial area. Results of blood tests did not change significantly after gene transfer. Conclusions Overall, an ultrasound-mediated gene transfer method with Optison enhanced the efficiency of gene transfer and expression in the rat kidney. This novel non-viral method may be useful for gene therapy for renal disease. Copyright © 2004 John Wiley & Sons, Ltd. [source] Influence of patient factors on the efficacy of breathing system filters at preventing contamination of breathing systems,ANAESTHESIA, Issue 5 2010S. Dugani Summary We measured the level of contamination in 207 breathing system filters of five different models. The median (IQR [range]) levels of contamination measured in relative light units on the machine side of the filters were: HMEF 750/S 27 (16,56 [4,13 615]); Ultipor BB25 26 (13,40 [9,66]); Humid-vent filter pedi 19 (15,34 [11,48]); Hygroboy 11 (7,19 [3,113]); and Hygrobaby 9 (6,14 [4,21]). A total of 41/138 (30%) of the HMEF 750/S (the most commonly used filter) had measured values > 50, indicating excessive contamination on the machine side of the filter. The incidence of coughing and duration of the case were significantly associated with the incidence of excessive contamination on the machine side (p = 0.034 and p = 0.024, respectively). Excessive contamination on the machine side of the filter could be from the patient or from the re-used breathing system and could result in cross-infection. The level of contamination may need to be checked routinely during each list. [source] | ||||||||||