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Fluorescence Spectrometer (fluorescence + spectrometer)
Selected AbstractsIndoor/outdoor concentrations and elemental composition of PM10/PM2.5 in urban/industrial areas of Kocaeli City, TurkeyINDOOR AIR, Issue 2 2010B. Pekey Abstract, This study presents indoor/outdoor PM2.5 and PM10 concentrations measured during winter and summer in 15 homes in Kocaeli, which is one of the most industrialized areas in Turkey. Indoor and outdoor PM2.5 and PM10 mass concentrations and elemental composition were determined using an X-ray fluorescence spectrometer. Quantitative information was obtained on mass concentrations and other characteristics such as seasonal variation, indoor/outdoor (I/O) ratio, PM2.5/PM10 ratio, correlations and sources. Average indoor and outdoor PM2.5 concentrations were 29.8 and 23.5 ,g/m3 for the summer period, and 24.4 and 21.8 ,g/m3 for the winter period, respectively. Average indoor and outdoor PM10 concentrations were 45.5 and 59.9 ,g/m3 for the summer period, and 56.9 and 102.3 ,g/m3 for the winter period, respectively. A varimax rotated factor analysis (FA) was performed separately on indoor and outdoor datasets in an effort to identify possible heavy metal sources of PM2.5 and PM10 particle fractions. FA of outdoor data produced source categories comprising polluted soil, industry, motor vehicles, and fossil fuel combustion for both PM fractions, while source categories determined for indoor data for both PM2.5 and PM10 comprised industry, polluted soil, motor vehicles, and smoking, with an additional source category of cooking activities detected for the PM2.5 fraction. Practical Implications In buildings close to industrial areas or traffic arteries, outdoor sources may have an important effect on indoor air pollution. Therefore, indoor and outdoor investigations should be conducted simultaneously to assess the relationship between indoor and outdoor pollution. This study presents the simultaneous measurement of PM fractions (PM2.5 and PM10) and their elemental compositions to determine the sources of respirable PM and the heavy metals bound to these particles in indoor air. Factor analysis of indoor data indicated that the contribution of outdoor pollutant sources to indoor pollution was about 70%, making these sources the most significant for indoor heavy metal pollution, wheras other sources of indoor pollution included smoking and cooking activities. [source] A fluorescence study on swelling of hydrogels (PAAm) at various cross-linker contentsADVANCES IN POLYMER TECHNOLOGY, Issue 4 2009Demet Kaya Akta Abstract Disk-shaped acrylamide (AAm) gels were prepared from AAm with various N,N,-methylenebisacrylamide (Bis) contents as cross-linker in the presence of ammonium persulfate as an initiator by free-radical cross-linking copolymerization in water. Polyacrylamide (PAAm) gels were dried before using for swelling experiments. Steady-state fluorescence spectrometer was employed during the swelling of PAAm hydrogels in water. Pyranine was introduced as a fluorescence probe. Fluorescence intensity of pyranine from various Bis content gel samples was measured during in situ swelling process. It was observed that fluorescence intensity decreased as swelling has proceeded. Gravimetric and volumetric experiments were also performed. The Li,Tanaka equation was used to determine the swelling time constants, ,c, and cooperative diffusion coefficients, Dc, from intensity, weight, and volume variations during the swelling processes. It was observed that swelling time constants, ,c, increased and diffusion coefficients, Dc, decreased as the cross-linker content was increased. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 28:215,223, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20163 [source] Synthesis of new S -glycodendrimer toward activation of lac operon transcription for protein biosynthesisJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2009Akinori Takasu To enable gene transcription or lac operon transcription, isopropyl ,- D -thiogalactoside (IPTG) and allolactose can bind to the lac repressor. New S -glycodendrimers for activation of the lac operon were synthesized by S -glycosidation and DCC-HOBt coupling with a poly(amidoamine) dendrimer. Expression of artificial protein was performed for Escherichia coli using these glycodendrimers as the inducers. Cells encoded with green fluorescent protein (GFP) were induced with the glycoconjugates. After expression at 37 °C for 4 h, fluorescence emissions were actually observed through visual observation, which indicated that S -glycodendrimer acted as an inducer for protein biosynthesis. Quantitative analysis using fluorescence spectrometer was carried out to evaluate the activity. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.] [source] Site-selective XAFS spectroscopy tuned to surface active sites of Cu/ZnO and Cr/SiO2 catalystsJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2001Yasuo Izumi XAFS (X-ray absorption fine structure) spectra were measured by using the fluorescence spectrometer for the emitted X-ray from sample. The chemical shifts between Cu0 and CuI and between CrIII and CrVI were evaluated. Tuning the fluorescence spectrometer to each energy, the Cu0 and CuI site-selective XANES for Cu/ZnO catalyst were measured. The first one was similar to the XANES of Cu metal and the second one was the 5 : 5 average of XANES for CuI sites + Cu metal. The population ratio of copper site of the Cu/ZnO catalyst was found to be Cu metal : Cu2O : CuI atomically dispersed on surface = 70(±23) : 22(±14) : 8(±5). Site-selective XANES for CrIII site of Cr/SiO2 catalyst was also studied. [source] Phase Transition Behavior of Novel pH-Sensitive Polyaspartamide Derivatives Grafted with 1-(3-Aminopropyl)imidazoleMACROMOLECULAR BIOSCIENCE, Issue 9 2006Kwangwon Seo Abstract Summary: New pH-sensitive polyaspartamide derivatives were synthesized by grafting 1-(3-aminopropyl)imidazole and/or O -(2-aminoethyl)- O,-methylpoly(ethylene glycol) 5000 on polysuccinimide for application in intracellular drug delivery systems. The DS of 1-(3-aminopropyl)imidazole was adjusted by the feed molar ratio, and the structure of the prepared polymer was confirmed using FT-IR and 1H NMR spectroscopy. Their pH-sensitive properties were characterized by light transmittance measurements, and the particle size and its distribution were investigated by dynamic light scattering measurements at varying pH values. The pH-sensitive phase transition was clearly observed in polymer solutions with a high substitution of 1-(3-aminopropyl)imidazole. The prepared polymers showed a high buffering capacity between pH 5 and 7, and this increased with the DS of 1-(3-aminopropyl)imidazole. The pH dependence of the aggregation and de-aggregation behavior was examined using a fluorescence spectrometer. For MPEG/imidazole- g -polyaspartamides with a DS of 1-(3-aminopropyl)imidazole over 82%, self aggregates associated with the hydrophobic interactions of the unprotonated imidazole groups were observed at pH values above 7, and their mean size was over 200 nm, while the aggregates of polymers were dissociated at pH values below 7 by the protonation of imidazole groups. These pH-sensitive polyaspartamide derivatives are potential basic candidates for intracellular drug delivery carriers triggered by small pH changes. Mean particle size change of MPEG/imidazole- g -polyaspartamide as pH is varied. [source] Effects of Low Power Laser Irradiation on Intracellular Calcium and Histamine Release in RBL-2H3 Mast CellsPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2007Wen-Zhong Yang Although laser irradiation has been reported to promote skin wound healing, the mechanism is still unclear. As mast cells are found to accumulate at the site of skin wounds we hypothesized that mast cells might be involved in the biological effects of laser irradiation. In this work the mast cells, RBL-2H3, were used in vitro to investigate the effects of laser irradiation on cellular responses. After laser irradiation, the amount of intracellular calcium ([Ca2+]i) was increased, followed by histamine release, as measured by confocal fluorescence microscopy with Fluo-3/AM staining and a fluorescence spectrometer with o -phthalaldehyde staining, respectively. The histamine release was mediated by the increment of [Ca2+]i from the influx of the extracellular buffer solution through the cation channel protein, transient receptor potential vanilloid 4 (TRPV4). The TRPV4 inhibitor, Ruthenium Red (RR) can effectively block such histamine release, indicating that TRPV4 was the key factor responding to laser irradiation. These induced responses of mast cells may provide an explanation for the biological effects of laser irradiation on promoting wound healing, as histamine is known to have multi-functions on accelerating wound healing. [source] Endogenous Fluorescence Spectroscopy of Cell Suspensions for Chemopreventive Drug Monitoring,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2005Nathaniel D. Kirkpatrick ABSTRACT Cancer chemopreventive agents such as N -4-(hydroxyphenyl)-retinamide (4HPR) are thought to prevent cancers by suppressing growth or inducing apoptosis in precancerous cells. Mechanisms by which these drugs affect cells are often not known, and the means to monitor their effects is not available. In this study endogenous fluorescence spectroscopy was used to measure metabolic changes in response to treatment with 4HPR in ovarian and bladder cancer cell lines. Fluorescence signals consistent with nicotinamide adenine dinucleotide (NADH), flavin adenine dinucleotide (FAD) and tryptophan were measured to monitor cellular activity through redox status and protein content. Cells were treated with varying concentrations of 4HPR and measured in a stable environment with a sensitive fluorescence spectrometer. Results suggest that redox signal of all cells changed in a similar dose-dependant manner but started at different baseline levels. Redox signal changes depended primarily on changes consistent with NADH fluorescence, whereas the FAD fluorescence remained relatively constant. Similarly, tryptophan fluorescence decreased with increased drug treatment, suggesting a decrease in protein production. Given that each cell line has been shown to have a different apoptotic response to 4HPR, fluorescence redox values along with changes in tryptophan fluorescence may be a response as well as an endpoint marker for chemopreventive drugs. [source] | |||||||||||||