Sample records for psoralen photooxidation products

  1. Psoralen-deoxyribonucleic acid photoreaction. Characterization of the monoaddition products from 8-methoxypsoralen and 4,5',8-trimethylpsoralen

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    Kanne, D.; Straub, K.; Rapoport, H.; Hearst, J.E.


    The isolation and structural characterization are described of the major monoaddition products formed in the photoreaction of two naturally occurring psoralens, 8-methoxypsoralen and 4,5',8-trimethylpsoralen, with high molecular weight, double-stranded DNA. Hydrolysis of the psoralen-modified DNA and subsequent chromatography resulted in the isolation of four modified nucleosides from each psoralen. Structural characterization was accomplished by mass spectrometry and /sup 1/H NMR analysis. The major products, accounting for 44 to 52% of the covalently bound psoralen, are two diastereomeric thymidine adducts formed by cycloaddition between the 5,6 double bond of the pyrimidine and the 4',5' (furan) double bond of the psoralen. All of the isolated adducts have cis-syn stereochemistry. The stereochemistry and product distribution of the adducts are determined in part by the constraints imposed by the DNA helix on the geometry of the noncovalent intercalation complex formed by psoralen and DNA prior to irradiation.

  2. The direct observation of a psoralen-thymine UVA induced solid-state cycloaddition reaction product by single-crystal x-ray diffractometry. (United States)

    Pfluger, C E; Ostrander, R L


    Single-crystal x-ray diffraction methods have been used to directly observe and simultaneously determine the molecular structure of the UVA induced cis-syn photocycloaddition product in a partially photolyzed single crystal of a psoralen(pyrone ring side)-DNA(thymine) interaction model compound, 1'-(8-oxypsoralen)-8'(thym-1"yl)3',6'-dioxaoctane.

  3. Hypertrichosis by Topical Psoralen

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    K Pavithran


    Full Text Available Two cases in which topical psoralen induced hypertrichosis in the depigmented patches of vitiligo are being reported. -The possible mechanisms for this hypertrichosis are briefly discussed.

  4. Reaction of the psoralens with deoxyribonucleic acid

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    Hearst, J.E.; Isaacs, S.T.; Kanne, D.; Rapoport, H.; Straub, K.


    This review has been limited to DNA reactions, and methods for radiolabelling psoralens, which have played an essential role in the isolation and purification of the photoproducts of the reaction between psoralens and nucleic acids, are reviewed herein. High-performance liquid chromatography procedures used for the separation of the photoadducts either as the nucleic adducts or as the free base adducts are discussed. Conclusions drawn from high-resolution proton magnetic resonance and high-resolution mass spectrometric studies of the structural determination of the isolated and purified adducts presented here have led to the assignment of the stereochemistry of the products and leave no doubt that the DNA helix influences both the kinetics and the stereospecificity of the photochemical reaction. The optical properties of the reactants and the photoproducts are catalogued. The kinetics of the photochemistry and its relationship to the fundamental properties of the various psoralen derivatives are discussed. 41 references, 19 figures, 8 tables.

  5. Rapid formation of isoprene photo-oxidation products observed in Amazonia

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    T. Karl


    Full Text Available Isoprene represents the single most important reactive hydrocarbon for atmospheric chemistry in the tropical atmosphere. It plays a central role in global and regional atmospheric chemistry and possible climate feedbacks. Photo-oxidation of primary hydrocarbons (e.g. isoprene leads to the formation of oxygenated VOCs (OVOCs. The evolution of these intermediates affects the oxidative capacity of the atmosphere (by reacting with OH and can contribute to secondary aerosol formation, a poorly understood process. An accurate and quantitative understanding of VOC oxidation processes is needed for model simulations of regional air quality and global climate. Based on field measurements conducted during the Amazonian Aerosol Characterization Experiment (AMAZE-08 we show that the production of certain OVOCs (e.g. hydroxyacetone from isoprene photo-oxidation in the lower atmosphere is significantly underpredicted by standard chemistry schemes. Recently reported fast secondary production could explain 50% of the observed discrepancy with the remaining part possibly produced via a novel primary production channel, which has been proposed theoretically. The observations of OVOCs are also used to test a recently proposed HOx recycling mechanism via degradation of isoprene peroxy radicals. If generalized our observations suggest that prompt photochemical formation of OVOCs and other uncertainties in VOC oxidation schemes could result in uncertainties of modelled OH reactivity, potentially explaining a fraction of the missing OH sink over forests which has previously been largely attributed to a missing source of primary biogenic VOCs.

  6. Lifetimes of organic photovoltaics: photooxidative degradation of a model compound

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    Norrman, K.; Alstrup, J.; Jørgensen, M.


    . The surface chemistry was monitored by TOF-SIMS and XPS. The experiment described accelerated photooxidation without any contributions from interface processes. The photooxidative degradation mechanisms are described starting from the intact molecule through presumably, intermediate photooxidation products...

  7. Front-face fluorescence measurement of photosensitizers and lipid oxidation products during the photooxidation of butter. (United States)

    Veberg, A; Olsen, E; Nilsen, A N; Wold, J P


    This paper shows that fluorescence spectroscopy can measure both degradation of photosensitizers and formation of lipid oxidation products in light-exposed butter. The photosensitizers were already notably degraded after 4 h of light exposure, whereas fluorescent lipid oxidation products were detected after 5 d. The fluorescence measurements were highly correlated with sensory assessments of acidic and rancid flavor. Photosensitizer degradation is therefore a promising indirect indicator of the onset of lipid oxidation in butter. Sensory analysis and measurement of peroxide value showed that the level of lipid oxidation was significantly higher for butter stored in air compared with butter stored in nitrogen (N2). This might be explained by the formation of singlet oxygen from direct photooxidation and type II photosensitized oxidation. Addition of the singlet oxygen quencher beta-carotene reduced the rancid flavor intensity in the air and N2 packages from 9.0 to 4.9 and from 6.5 to 4.7, respectively. Results indicate that lipid oxidation in the butter stored in N2 was mainly caused by type I photosensitized reactions, because addition of beta-carotene had little effect on the rancid flavor intensity.

  8. Inactivated human platelet lysate with psoralen: a new perspective for mesenchymal stromal cell production in Good Manufacturing Practice conditions. (United States)

    Castiglia, Sara; Mareschi, Katia; Labanca, Luciana; Lucania, Graziella; Leone, Marco; Sanavio, Fiorella; Castello, Laura; Rustichelli, Deborah; Signorino, Elena; Gunetti, Monica; Bergallo, Massimiliano; Bordiga, Anna Maria; Ferrero, Ivana; Fagioli, Franca


    Mesenchymal stromal cells (MSC) are ideal candidates for regenerative and immunomodulatory therapies. The use of xenogeneic protein-free Good Manufacturing Practice-compliant growth media is a prerequisite for clinical MSC isolation and expansion. Human platelet lysate (HPL) has been efficiently implemented into MSC clinical manufacturing as a substitute for fetal bovine serum (FBS). Because the use of human-derived blood materials alleviates immunologic risks but not the transmission of blood-borne viruses, the aim of our study was to test an even safer alternative than HPL to FBS: HPL subjected to pathogen inactivation by psoralen (iHPL). Bone marrow samples were plated and expanded in α-minimum essential medium with 10% of three culture supplements: HPL, iHPL and FBS, at the same time. MSC morphology, growth and immunophenotype were analyzed at each passage. Karyotype, tumorigenicity and sterility were analyzed at the third passage. Statistical analyses were performed. The MSCs cultivated in the three different culture conditions showed no significant differences in terms of fibroblast colony-forming unit number, immunophenotype or in their multipotent capacity. Conversely, the HPL/iHPL-MSCs were smaller, more numerous, had a higher proliferative potential and showed a higher Oct-3/4 and NANOG protein expression than did FBS-MSCs. Although HPL/iHPL-MSCs exhibit characteristics that may be attributable to a higher primitive stemness than FBS-MSCs, no tumorigenic mutations or karyotype modifications were observed. We demonstrated that iHPL is safer than HPL and represents a good, Good Manufacturing Practice-compliant alternative to FBS for MSC clinical production that is even more advantageous in terms of cellular growth and stemness. Copyright © 2014 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  9. Photo-oxidation products of skin surface squalene mediate metabolic and inflammatory responses to solar UV in human keratinocytes.

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    Vladimir Kostyuk

    Full Text Available The study aimed to identify endogenous lipid mediators of metabolic and inflammatory responses of human keratinocytes to solar UV irradiation. Physiologically relevant doses of solar simulated UVA+UVB were applied to human skin surface lipids (SSL or to primary cultures of normal human epidermal keratinocytes (NHEK. The decay of photo-sensitive lipid-soluble components, alpha-tocopherol, squalene (Sq, and cholesterol in SSL was analysed and products of squalene photo-oxidation (SqPx were quantitatively isolated from irradiated SSL. When administered directly to NHEK, low-dose solar UVA+UVB induced time-dependent inflammatory and metabolic responses. To mimic UVA+UVB action, NHEK were exposed to intact or photo-oxidised SSL, Sq or SqPx, 4-hydroxy-2-nonenal (4-HNE, and the product of tryptophan photo-oxidation 6-formylindolo[3,2-b]carbazole (FICZ. FICZ activated exclusively metabolic responses characteristic for UV, i.e. the aryl hydrocarbon receptor (AhR machinery and downstream CYP1A1/CYP1B1 gene expression, while 4-HNE slightly stimulated inflammatory UV markers IL-6, COX-2, and iNOS genes. On contrast, SqPx induced the majority of metabolic and inflammatory responses characteristic for UVA+UVB, acting via AhR, EGFR, and G-protein-coupled arachidonic acid receptor (G2A.Our findings indicate that Sq could be a primary sensor of solar UV irradiation in human SSL, and products of its photo-oxidation mediate/induce metabolic and inflammatory responses of keratinocytes to UVA+UVB, which could be relevant for skin inflammation in the sun-exposed oily skin.

  10. Psoralen-ultraviolet A treatment with Psoralen-ultraviolet B therapy in the treatment of psoriasis. (United States)

    Ahmed Asim, Sadaf; Ahmed, Sitwat; Us-Sehar, Najam


    To compare the conventional psoralen-ultraviolet A treatment with psoralen-ultraviolet B therapy in the treatment of psoriasis. We studied 50 patients of plaque type psoriasis who were selected to receive either conventional psoralen-ultraviolet A or psoralen-ultraviolet B treatment. There was no significant difference between the two treatment groups in the number of patients whose skin cleared of psoriasis or the number of exposures required for clearance. Profile of side effects and disease status was also similar after three months of follow up. Psoralen-ultraviolet B treatment is as effective as conventional psoralen-ultraviolet A in the treatment of psoriasis. Further long term studies are needed to assess the safety of psoralen-ultraviolet B.

  11. A method for fast determination of psoralens in oral solutions of phytomedicines using liquid chromatography. (United States)

    Pires, Adriana Elias; Honda, Neli Kiko; Cardoso, Cláudia Andréa Lima


    A method for sample preparation and analysis by high performance liquid chromatography with UV detection (HPLC-UV) has been developed for routine analysis of psoralen and bergapten, photosensitizing compounds, in oral solutions of phytomedicines employed in Brazil for some illnesses. The linearity, accuracy, the inter- and intra-day precision of the procedure were evaluated. Calibration curves for psoralen and bergapten were linear in the range of 1.0-600.0 microg ml(-1) and 1.0-400.0 microg ml(-1) respectively. The recoveries of the psoralens in the oral solutions analysed were 94.43-99.97%. The percentage coefficient of variation (CV) of the quantitative analysis of the psoralens in the products analysis was within 5%. In inter-equipment study was employed gas chromatography-flame ionization (CG-FID) detection.

  12. Photo-oxidation of low-volatility organics found in motor vehicle emissions: production and chemical evolution of organic aerosol mass. (United States)

    Miracolo, Marissa A; Presto, Albert A; Lambe, Andrew T; Hennigan, Christopher J; Donahue, Neil M; Kroll, Jesse H; Worsnop, Douglas R; Robinson, Allen L


    Recent research has proposed that low-volatility organic vapors are an important class of secondary organic aerosol (SOA) precursors. Mixtures of low-volatility organics were photo-oxidized in a smog chamber under low- and high-NO(x) conditions. Separate experiments addressed emission surrogates (diesel fuel and motor oil) and single components (n-pentacosane). Both diesel fuel and motor oil are major components of exhaust from diesel engines. Diesel fuel is a complex mixture of intermediate volatility organic compounds (IVOCs), whereas motor oil is a complex mixture of semivolatile organic compounds (SVOCs). IVOCs exist exclusively in the vapor phase, while SVOCs exist in both the aerosol and vapor phase. Oxidation of SVOC vapors (motor oil and n-pentacosane) creates substantial SOA, but this SOA is largely offset by evaporation of primary organic aerosol (POA). The net effect is a cycling or pumping of SVOCs between the gas and particle phases, which creates more oxygenated organic aerosol (OA) but little new OA mass. Since gas-phase reactions are much faster than heterogeneous ones, the processing of SVOC vapors likely contributes to the production of highly oxidized OA. The interplay between gas-particle partitioning and chemistry also blurs traditional definitions of POA and SOA. Photo-oxidation of diesel fuel (IVOCs) rapidly creates substantial new OA mass, similar to published aging experiments with dilute diesel exhaust. However, aerosol mass spectrometer (AMS) data indicated that the SOA formed from emission surrogates is less oxidized than either the oxygenated organic aerosol (OOA) measured in the atmosphere or SOA formed from the photo-oxidation of dilute diesel exhaust. Therefore, photo-oxidation of IVOCs helps explain the substantial SOA mass produced from aging diesel exhaust, but some component is missing from these emission surrogate experiments that leads to the rapid production of highly oxygenated SOA.

  13. Photochemistry of psoralen-DNA adducts, biological effects of psoralen-DNA adducts, applications of psoralen-DNA photochemistry

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    Shi, Yun-bo


    This thesis consists of three main parts and totally eight chapters. In Part I, The author will present studies on the photochemistry of psoralen-DNA adducts, specifically, the wavelength dependencies for the photoreversals of thymidine-HMT (4'-hydroxymethyl-4, 5', 8-trimenthylpsoralen) monoadducts and diadduct and the same adducts incorporated in DNA helices and the wavelength dependecies for the photocrossslinking of thymidine-HMT monoadducts in double-stranded helices. In Part II, The author will report some biological effects of psoralen-DNA adducts, i.e., the effects on double-stranded DNA stability, DNA structure, and transcription by E. coli and T7 RNA polymerases. Finally, The author will focus on the applications of psoralen-DNA photochemistry to investigation of protein-DNA interaction during transcription, which includes the interaction of E. coli and T7 RNA polymerases with DNA in elongation complexes arrested at specific psoralen-DNA adduct sites as revealed by DNase I footprinting experiments. 123 refs., 52 figs., 12 tabs.

  14. Photooxidative degradation of beer bittering principles: product analysis with respect to lightstruck flavour formation. (United States)

    Huvaere, Kevin; Sinnaeve, Bart; Van Bocxlaer, Jan; De Keukeleire, Denis


    Isohumulones, the main bittering agents in beer, are decomposed by light-induced reactions, thereby leading to radical precursors on the pathway to lightstruck flavour formation. Excited flavins, formed on visible-light irradiation, readily interact with isohumulones, as well as with reduced and oxidized derivatives thereof. From identification of both volatile and non-volatile reaction products thus formed, feasible degradation mechanisms are proposed.

  15. Observation of 2-methyltetrols and related photo-oxidation products of isoprene in boreal forest aerosols from Hyytiälä, Finland

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    I. Kourtchev


    Full Text Available Oxidation products of isoprene including 2-methyltetrols (2-methylthreitol and 2-methylerythritol, 2-methylglyceric acid and triol derivatives of isoprene (2-methyl-1,3,4-trihydroxy-1-butene (cis and trans and 3-methyl-2,3,4-trihydroxy-1-butene have been detected in boreal forest PM1 aerosols collected at Hyytiälä, southern Finland, during a 2004 summer period, at significant atmospheric concentrations (in total 51 ng m−3 in summer versus 0.46 ng m−3 in fall. On the basis of these results, it can be concluded that photo-oxidation of isoprene is an important atmospheric chemistry process that contributes to secondary organic aerosol formation during summer in this conifer forest ecosystem. In addition to isoprene oxidation products, malic acid, which can be regarded as an intermediate in the oxidation of unsaturated fatty acids, was also detected at high concentrations during the summer period (46 ng m−3 in summer versus 5.2 ng m−3 in fall, while levoglucosan, originating from biomass burning, became relatively more important during the fall period (29 ng m−3 in fall versus 10 ng m−3 in summer. Pinic acid, a major photo-oxidation product of α-pinene in laboratory experiments, could only be detected at trace levels in the summer samples, suggesting that further oxidation of pinic acid occurs and/or that different oxidation pathways are followed. We hypothesize that photo-oxidation of isoprene may participate in the early stages of new particle formation, a phenomenon which has been well documented in the boreal forest environment.

  16. Laboratory studies of carbon kinetic isotope effects on the production mechanism of particulate phenolic compounds formed by toluene photooxidation: a tool to constrain reaction pathways. (United States)

    Irei, Satoshi; Rudolph, Jochen; Huang, Lin; Auld, Janeen; Collin, Fabrice; Hastie, Donald


    In this study, we examined compound-specific stable carbon isotope ratios for phenolic compounds in secondary organic aerosol (SOA) formed by photooxidation of isotope-label-free toluene. SOA generated by photooxidation of toluene using a continuous-flow reactor and an 8 m(3) indoor smog chamber was collected on filters, which were extracted with acetonitrile for compound-specific analysis. Eight phenolic compounds were identified in the extracts using a gas chromatograph coupled with a mass spectrometer, and their compound-specific stable carbon isotope ratios were determined using a gas chromatograph coupled with a combustion furnace followed by an isotope ratio mass spectrometer. The majority of products, including methylnitrophenols and methylnitrocatechols, were isotopically depleted by 5-6‰ compared to the initial isotope ratio of toluene, whereas the isotope ratio for 4-nitrophenol remained identical to that of toluene. On the basis of the reaction mechanisms proposed in previous reports, stable carbon isotope ratios of these products were calculated. By comparing the observed isotope ratios with the predicted isotope ratios, we explored possible production pathways for the particulate phenolic compounds.

  17. Online Measurements and Modeling of Isoprene Photo-oxidation Products: Insights from the Laboratory and SOAS Field Campaign (United States)

    D'Ambro, E.; Lopez-Hilfiker, F.; Mohr, C.; Gaston, C.; Lee, B. H.; Liu, J.; Lutz, A.; Hallquist, M.; Shilling, J.; Gold, A.; Zhang, Z.; Surratt, J. D.; Thornton, J. A.; Schobesberger, S.


    Isoprene, the most abundant non-methane volatile organic compound emitted globally, has the potential to produce large quantities of secondary organic aerosol (SOA) with implications for climate, air quality, and human health. However, much remains unknown about the mechanisms and processes that lead to isoprene derived SOA. We present measurements and modeling of a suite of newly detected compounds from isoprene oxidation from laboratory studies at the Pacific Northwest National Laboratory (PNNL) as well as in the atmosphere from the Southern Oxidant and Aerosol Study (SOAS) field campaign. Measurements were made with a high resolution time of flight chemical ionization mass spectrometer utilizing iodide adduct ionization coupled to the Filter Inlet for Gas and AEROsol (FIGAERO) for the simultaneous sampling of the gas and aerosol phases. In the PNNL chamber, isoprene photo-oxidation with dry neutral seed and IEPOX multiphase chemistry on aqueous particles was investigated at a variety of atmospherically relevant conditions. Isoprene photo-oxidation under high HO2 produced unexpectedly substantial SOA at a yield similar to but from a distinctly different mechanism than that from IEPOX uptake. The high HO2 chemistry also resulted in di hydroxy di hydroperoxides as a dominant component of the aerosol. By utilizing the same instrument and ion chemistry during both field and chamber experiments, together with an MCM-based model, we assess the degree to which the different mechanisms are operable in the atmosphere and relevant aerosol chemical and physical properties of the SOA such as volatility and oligomer content.

  18. Isolation and characterization of pyrimidine-psoralen photoadducts from DNA

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    Straub, K.; Kanne, D.; Hearst, J.E.; Rapoport, H.


    We have examined the photoadducts of 4'-hydroxymethyl-4,5',8-trimethylpsoralen (HMT) and native DNA. Five nucleoside-HMT monoaddition products have been isolated and characterized, corresponding to three deoxythymidine-HMT and two deoxyuridine (derived from deoxycytidine)-HMT adducts. Structural assignments are based on high resolution mass spectrometry and /sup 1/H NMR studies, including homonuclear spin decoupling and nuclear Overhauser effect (NOE) experiments. The results of this study indicate that (1) a limited number of nucleoside-psoralen adducts are formed with native, double-stranded DNA, and (2) the sterochemistry of the adducts is apparently determined by the geometry of the noncovalent intercalative complex formed by HMT and DNA prior to irradiation. 8 figures, 8 tables.

  19. Measurements of photo-oxidation products from the reaction of a series of alkyl-benzenes with hydroxyl radicals during EXACT using comprehensive gas chromatography

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    J. F. Hamilton


    Full Text Available Photo-oxidation products from the reaction of a series of alkyl-benzenes, (benzene, toluene, p-xylene and 1,3,5-trimethyl-benzene with hydroxyl radicals in the presence of NOx have been investigated using comprehensive gas chromatography (GCxGC. A GCxGC system has been developed which utilises valve modulation and independent separations as a function of both volatility and polarity. A number of carbonyl-type compounds were identified during a series of reactions carried out at the European Photoreactor (EUPHORE, a large volume outdoor reaction chamber in Valencia, Spain. Experiments were carried as part of the EXACT project (Effects of the oXidation of Aromatic Compounds in the Troposphere. Two litre chamber air samples were cryo-focused, with a sampling frequency of 30 minutes, allowing the evolution of species to be followed over oxidation periods of 3-6 hours. To facilitate product identification, several carbonyl compounds, which were possible products of the photo-oxidation, were synthesised and used as reference standards. For toluene reactions, observed oxygenated intermediates found included the co-eluting pair a-angelicalactone/4-oxo-2-pentenal, maleic anhydride, citraconic anhydride, benzaldehyde and p-methyl benzoquinone. In the p-xylene experiment, the products identified were E/Z-hex-3-en-2,5-dione and citraconic anhydride. For 1,3,5-TMB reactions, the products identified were 3,5-dimethylbenzaldehyde, 3,5-dimethyl-3H-furan-2-one and 3-methyl-5-methylene-5H-furan-2-one. Preliminary quantification was carried out on identified compounds using liquid standards. Comparison of FTIR and GCxGC for the measurement of the parent aromatics generally showed good agreement. Comparison of the concentrations observed by GCxGC to concentration-time profiles simulated using the Master Chemical Mechanism, MCMv3, demonstrates that this mechanism significantly over-predicts the concentrations of many product compounds and highlights the

  20. Psoralens and coumarins for receptor targeting on epidermal cells

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    Jetter, M.M.


    Specific binding sites have been identified for the psoralens, discrete from DNA, in different epidermal cell lines. These receptors are saturable and are alkylated by the action of psoralens + UVA light. A psoralen receptor has been partially purified and established to be a protein of approximately 20,000 daltons. Inhibition of the binding of epidermal growth factor to its receptor and inhibition of the tyrosine kinase activity of the EGF receptor has been associated with PUVA treatment. These findings conflict with the general assumption that the biological effects of psoralens as photoactive compounds are associated with their ability to covalently bind to and crosslink DNA. In collaboration with Laskin's,laboratory, several classes of psoralen agonists were synthesized. These compounds include coumarins, furocoumarin and benzodipyran-2-one derivatives. The methods of preparation were varied and include variants of the Claisen rearrangement, acid and base-catalyzed condensations. The synthesized compounds were tested for their potential inhibition of {sup 125}I-EGF receptor binding. It was discovered that many of these agents showed potent inhibition activity similar to the psoralens. This data offers the possibility that sites of action, other than DNA, are involved in the mechanism by which photoactivated psoralens modulate epidermal cell lines.

  1. Photooxidation of phytochemicals in food and control: a review. (United States)

    Lu, Baiyi; Zhao, Yajing


    Phytochemicals are widely present in food and have been confirmed to be bioactive, thereby contributing to human health. However, some phytochemicals are sensitive to light owing to their structures and may suffer from photodegradation, especially when sensitizers exist, resulting in sensory quality change, nutrient loss in food, and even the formation of toxic compounds. The photooxidation of phytochemicals occurs through three different mechanisms: (1) by directly absorbing luminous energy, (2) with triplet-excited state sensitizers through electron transfer or proton transfer (type I photooxidation), and (3) with singlet oxygen produced by O 2 (type II photooxidation). On the basis of these mechanisms, adequate antioxidants can be added to quench the triple-excited state sensitizers or singlet oxygen to protect against the photooxidation of phytochemicals in food. Here, we summarize and discuss the possible pathways and products of the photooxidation of phytochemicals that have been reported and the relationships between structures and photooxidation. We also propose some control measures, with special attention paid to the potential abilities of phytochemicals in the prevention of food photooxidation. © 2017 New York Academy of Sciences.

  2. X-Ray Psoralen Activated Cancer Therapy (X-PACT.

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    Mark Oldham

    Full Text Available This work investigates X-PACT (X-ray Psoralen Activated Cancer Therapy: a new approach for the treatment of solid cancer. X-PACT utilizes psoralen, a potent anti-cancer therapeutic with current application to proliferative disease and extracorporeal photopheresis (ECP of cutaneous T Cell Lymphoma. An immunogenic role for light-activated psoralen has been reported, contributing to long-term clinical responses. Psoralen therapies have to-date been limited to superficial or extracorporeal scenarios due to the requirement for psoralen activation by UVA light, which has limited penetration in tissue. X-PACT solves this challenge by activating psoralen with UV light emitted from novel non-tethered phosphors (co-incubated with psoralen that absorb x-rays and re-radiate (phosphoresce at UV wavelengths. The efficacy of X-PACT was evaluated in both in-vitro and in-vivo settings. In-vitro studies utilized breast (4T1, glioma (CT2A and sarcoma (KP-B cell lines. Cells were exposed to X-PACT treatments where the concentrations of drug (psoralen and phosphor and radiation parameters (energy, dose, and dose rate were varied. Efficacy was evaluated primarily using flow cell cytometry in combination with complimentary assays, and the in-vivo mouse study. In an in-vitro study, we show that X-PACT induces significant tumor cell apoptosis and cytotoxicity, unlike psoralen or phosphor alone (p<0.0001. We also show that apoptosis increases as doses of phosphor, psoralen, or radiation increase. Finally, in an in-vivo pilot study of BALBc mice with syngeneic 4T1 tumors, we show that the rate of tumor growth is slower with X-PACT than with saline or AMT + X-ray (p<0.0001. Overall these studies demonstrate a potential therapeutic effect for X-PACT, and provide a foundation and rationale for future studies. In summary, X-PACT represents a novel treatment approach in which well-tolerated low doses of x-ray radiation are delivered to a specific tumor site to generate UVA

  3. Toxicity of a PAH photooxidation product to the bacteria Photobacterium phosphoreum and the duckweed Lemna gibba: Effects of phenanthrene and its primary photoproduct, phenanthrenequinone

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    McConkey, B.J.; Duxbury, C.L.; Dixon, D.G.; Greenberg, B.M. [Univ. of Waterloo, Ontario (Canada). Dept. of Biology


    Phenanthrene (PHE) undergoes a significant increase in toxicity after exposure to simulated or natural sunlight in aqueous media, coincident with the appearance of PHE photoproducts. To investigate whether the primary photoproduct of PHE, 9,10-phenanthrenequinone (PHEQ), contributes to the increased hazards of solutions containing photomodified PHE, toxicity assays were conducted using the marine bacteria Photobacterium phosphoreum and the aquatic plant Lemna gibba (duckweed). Photobacterium phosphoreum was exposed to PHE, PHEQ, a photomodified PHE mixture containing known amounts of PHE and PHEQ (pmPHE), and a mixture mimicking the amounts of PHE and PHEQ in the pmPHE mixture. The bacteria were found to be equally sensitive to PHE in simulated solar radiation or darkness, with an EC50 of 0.53 mg/L. In both darkness or SSR, solutions containing PHEQ (with or without PHE) all exhibited an EC50 of 0.06 to 0.10 mg/L based on PHEQ concentrations, indicating that PHEQ was the primary active component of the pmPHE mixture. Lemna gibba was tested in SSR and visible light with PHE, PHEQ, and the pmPHE mixture. The calculated EC50 for PHE was 3.5 mg/L in SSR and 10.8 mg/L in visible light, showing that the presence of UV radiation in the SSR source increased the phytotoxicity of PHE. Strikingly, PHEQ was much more toxic to L. gibba than PHE in a light-independent manner. Thus, for both P. phosphoreum and L. gibba the major photooxidation product of PHE in SSR, PHEQ, is the more toxic of the two chemicals.

  4. Mass Spectrometry Study of OH-initiated Photooxidation of Toluene (United States)

    Huang, Ming-qiang; Zhang, Wei-jun; Wang, Zhen-ya; Fang, Li; Kong, Rui-hong; Shan, Xiao-bin; Liu, Fu-yi; Sheng, Liu-si


    The composition of products formed from photooxidation of the aromatic hydrocarbon toluene was investigated. The OH-initiated photooxidation experiments were conducted by irradiating toluene/CH3ONO/NO/air mixtures in a smog chamber, the gaseous products were detected under the supersonic beam conditions by utilizing vacuum ultraviolet photoionization mass spectrometer using synchrotron radiation in real-time. And an aerosol time-of-flight mass spectrometer was used to provide on-line measurements of the individual secondary organic aerosol particle resulting from irradiating toluene. The experimental results demonstrated that there were some differences between the gaseous products and that of particle-phase, the products of glyoxal, 2-hydroxyl-3-oxo-butanal, nitrotoluene, and methyl-nitrophenol only existed in the particle-phase. However, furane, methylglyoxal, 2-methylfurane, benzaldehyde, cresol, and benzoic acid were the predominant photooxidation products in both the gas phase and particle phase.

  5. TiO2 assisted photo-oxidative pretreatment of wheat straw for biogas production

    DEFF Research Database (Denmark)

    Awais, Muhammad; Alvarado-Morales, Merlin; Tsapekos, Panagiotis

    (i.e. 0.5, 1, 1.5 and 2 wt%) with four different exposure time periods (i.e. 0, 60, 120 and 180 min) were investigated under 700W medium pressure UV lamp radiations. Subsequently, biochemical methane potentials (BMPs) assays were conducted under thermophilic conditions for the different pretreated...... to enhance biomass biodegradability in anaerobic digestion (AD) process. Thus, the present study elucidated the photo-catalytic oxidation of highly lignified wheat straw using TiO2at the presence of UV light in the region of 300-360nm. Specifically, the combinations of four different concentrations of TiO2...... microscopy (SEM) images of the pretreated wheat straw that showed augmented damaged areas and development of pits after the pretreatment. In addition, the products of oxidation were also measured, as it was expected the lignin to be oxidized into phenolic acids. For instance, vanillic acid was found...

  6. Stable Carbon Isotope Ratios of Specific Products in Secondary Particulate Organic Matter Formed by Photo-Oxidation of Toluene (United States)

    Irei, S.; Rudolph, J.; Huang, L.; Auld, J.; Hastie, D.


    Laboratory experiments for stable carbon isotope studies of secondary particulate organic matter (POM) in the gas-phase were conducted. Secondary POM was generated using a 2.5 L flow reactor or an 8 m3 smog chamber. The initial mixing ratio of toluene and the initial toluene/NO ratio were 20 ppmV - 40 ppmV and 4 - 8 for the flow reactor experiments and ~0.5 ppmV and 0.3 - 2 for the smog chamber experiments, respectively. The flow reactor experiments were made without seed particles, while the smog chamber experiments were done with ammonium sulfate seed particles. Using these different experimental set-ups/conditions, POM generated under different extent of toluene consumption was collected on filters for compound-specific stable carbon isotope analysis as well as for the stable carbon isotope analysis of total POM carbon. For the compound specific analysis, the collected filter samples were extracted with acetonitrile, and the extracts were then concentrated under a gentle flow of pure nitrogen gas. The concentrated extracts were derivatized using N, O-bis(trimethylsilyl)trifluoroacetoamide (BSTFA). The derivatives were qualitatively and quantitatively/isotopically analyzed by GC-MS and GC-C-IRMS, respectively. The qualitative analysis by the GC-MS identified 7 nitromonohydroxy/nitrodihydroxy aromatic compounds in the POM extracts. The results from the compound-specific stable carbon analysis show that, for 6 out of the 7 identified products, the isotope ratios were the similar to that of the total POM carbon, which is predictable using the kinetic isotope effect of the initial toluene+OH reaction, the initial isotope ratio of toluene, and fraction of toluene consumed (Irei et al., 2006). In this presentation, comparison of these observations with the reaction mechanisms postulated by others will be discussed. Reference Flow reactor studies for stable carbon isotopic composition of secondary particulate organic matter generated by toluene/OH radical

  7. Isolation and purification of psoralen and isopsoralen and their ...

    African Journals Online (AJOL)

    Nude rat model of osteosarcoma was established; the rats were randomized into: normal saline group, psoralen low- and high-dose groups, isopsoralen low- and high-dose groups, and cisplatin group. Osteosarcoma volume and weight inhibition rates in nude rats in each group were observed; radioimmunoassay was ...

  8. Isolation and purification of psoralen and isopsoralen and their ...

    African Journals Online (AJOL)

    into: normal saline group, psoralen low- and high-dose groups, isopsoralen low- and high-dose groups, and cisplatin group. Osteosarcoma volume and weight inhibition rates in nude rats in each group were observed; radioimmunoassay was used to determine the serum alkaline phosphatase activity; peripheral blood cell ...

  9. Isolation and purification of psoralen and isopsoralen and their ...

    African Journals Online (AJOL)

    Isolation and purification of psoralen and isopsoralen and their efficacy and safety in the treatment of osteosarcoma in nude rats. Honghui Lu¥ , Lihai Zhang¥, Daohong Liu, Peifu Tang2, Feixiang Song. Orthopaedic Department , People's Liberation Army General Hospital, Beijing 100000, China. ¥Authors Contributed ...

  10. Isolation and characterization of pyrimidine-psoralen-pyrimidine photodiadducts from DNA. [Ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kanne, D.; Straub, K.; Hearst, J.E.; Rapoport, H.


    The isolation and characterization of pyrimidine-psoralen-pyrimidine photodiadducts from DNA are reported for the first time. For each of the four psoralens studied, a single pair of diastereomeric thymidine-psoralen-thymidine photodiadducts, each with cis-syn stereochemistry, was found to account for > 90% of the diadducts formed. Additionally, pulse-chase experiments that establish that these photo cross-links are formed by cycloaddition of a second thymidine residue to the 3,4 double bond (pyrone side) of an initially formed 4',5' (furan-side) psoralen-thymidine photomonoadduct have been carried out.

  11. Mutagenic atmospheres resulting from the photooxidation of aromatic hydrocarbon and NOx mixtures (United States)

    U.S. Environmental Protection Agency — Although many volatile organic compounds (VOCs) are regulated to limit air pollution and the consequent health effects, the photooxidation products generally are...

  12. Cavamax W7 composite psoralen ethosomal gel versus cavamax W7 psoralen solid complex gel for topical delivery: A comparative evaluation (United States)

    Kumari, Smriti; Pathak, Kamla


    Aim: The present research work was aimed to formulate and characterize psoralen-encapsulated cavamax W7 composite ethosomal gel and compare its in vitro and ex vivo behavior against psoralen-cavamax W7-complex reference gel. Materials and Methods: A total of nine formulations of composite ethosomes were prepared by injection method using 32 factorial design and entrapment efficiency was designated as dependent variable. Concomitantly, psoralen was complexed with cavamax W7 (1:1 molar ratio) by kneading method and formation of complex was confirmed by Diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). Results: F9 with vesicle size of 183 ± 2.8 nm, and highest % entrapment efficiency of 98.12 ± 1.15 was selected as optimized formulation. Transmission electron microscopy (TEM) revealed uniform and spherical shaped vesicles. The optimized formulation F9 was formulated as carbapol gel and compared against ethosomal gel, psoralen gel, and psoralen cavamax W7 complex gel. The gels were evaluated for permeation characteristics and the rank order was composite ethosomal gel > ethosomal gel > psoralen-cavamax W7 complex gel > psoralen gel. The ethosomal gel (G5) with highest in vitro permeation of 82.48 ± 2.23% was subjected to in vivo Confocal laser scanning microscopy (CLSM) studies using rhodamine B as tracer. The penetration of rhodamine B was uniform, deeper, and two times faster into epidermis than control gel. Conclusion: Conclusively, cavamax W7 composite ethosomes present themselves as efficient carrier for superior topical delivery of psoralen and have potential for clinical applications in minimizing side effects associated with photosensitivity of psoralen. PMID:24350036

  13. Photooxidation of olefins sensitized by bisazafullerene (C(59)N)(2) and hydroazafullerene C(59)HN: product analysis, emission of singlet oxygen, and transient absorption spectroscopy. (United States)

    Tagmatarchis, N; Shinohara, H; Fujitsuka, M; Ito, O


    The photooxidation reactions of olefins sensitized by the excited triplet states of bisazafullerene (C(59)N)(2) and hydroazafullerene C(59)HN have been studied. Oxidation yields were compared with those of pristine C(60). The singlet oxygen yields are also determined directly from the emission intensities, which are in good agreement with the oxidation yields. The triplet states of (C(59)N)(2) and C(59)HN have been identified by the time-resolved spectroscopic method by observing the triplet-triplet absorption spectra, which decay in the presence of oxygen. It has been proven that (C(59)N)(2) and C(59)HN have the ability to sensitize the reactions via singlet oxygen in about half of the efficiency of that of pristine C(60). For both azafullerenes, the triplet lifetimes are shorter than that of pristine C(60), which may be related to the nitrogen atom embedded in the C(60) moiety.

  14. Site specificity of psoralen-DNA interstrand cross-linking determined by nuclease Bal31 digestion

    DEFF Research Database (Denmark)

    Zhen, W P; Buchardt, O; Nielsen, Henrik


    was analyzed, and these two psoralens showed identical site specificity. The 5'-TA preference is rationalized on the basis of the local DNA structure in terms of the pi-pi electronic interaction between the thymines and the intercalated psoralens, as well as on the base tilt angles of the DNA....

  15. [Mechanism of photooxidation of porphyrins with oxygen]. (United States)

    Byteva, I M; Gurinovich, G P; Petsol'd, O M


    Dependence of quantum yield of porphyrines photooxidation with oxygen on their concentration has been shown. Sensitized by some porphyrines oxidation of other ones with oxygen has been studied in relation to concentration, intensity and wave length of absorbed light, quantum yield, interconversion and life time of the molecules in triplet state. Common mechanism for direct and sensitized photooxidation has been suggested.

  16. Effects of nuclear isolation on psoralen affinity for chromatin

    Energy Technology Data Exchange (ETDEWEB)

    Inadomi, T.; Ross, P.M. (Rockefeller Univ., New York, NY (USA))


    We have tested the effects of nuclear isolation on intercalation of TMP (a psoralen) at specific sequences and in total DNA of cultured human cells. DNA in nuclei photobound about 20% more TMP than in cells and about 10% as much as purified DNA. In contrast, a transcribed ras gene and a randomly selected polymorphic sequence each bound about 20% more TMP than total DNA in cells. However, in nuclei, as in purified DNA, both sequences were just as sensitive as total DNA. Apparently, chromatin in cells exists within diverse TMP-binding environments and some of this diversity was lost upon nuclear isolation.

  17. Psoralen-containing sunscreen is tumorigenic in hairless mice

    Energy Technology Data Exchange (ETDEWEB)

    Cartwright, L.E.; Walter, J.F.


    Sunscreens containing 5-methoxypsoralen (5-MOP) are currently being marketed to promote tanning by inducing psoralen-mediated ultraviolet (UV) A (320-400 nm) melanogenesis. The rationale is that this may prevent UVB (290-320 nm) radiation-induced skin damage. However, mouse studies have shown that 5-MOP has the same cutaneous photocarcinogenic potential as 8-methoxypsoralen. In addition, the 5-MOP--containing sunscreen Sun System III (SS III), when combined with UVA, induces epidermal ornithine decarboxylase activity, an enzyme associated with tumor promotion. Therefore, we investigated whether SS III had sufficient psoralen concentration to be tumorigenic in hairless mice exposed to chronic, intermittent UVA radiation. SS III was applied to hairless mice 5 days per week for 20 weeks. After each application the mice were exposed to 2.5 to 10 joules/cm2 UVA radiation. All test groups developed atypical squamous papillomas in direct proportion to the dosage of UVA radiation received. A shorter latency period for tumor development was seen with larger UVA doses. Test animals followed up to 1 year developed invasive squamous cell tumors. Control groups (SS III without UVA and UVA without SS III) remained free of tumors. Animals receiving SS III plus UVA developed persistent skin thickening and increased dermal cyst formation similar to that reported with chronic exposure to UVB, a known carcinogenic wavelength.

  18. Evaluation of psoralen ethosomes for topical delivery in rats by using in vivo microdialysis. (United States)

    Zhang, Yong-Tai; Shen, Li-Na; Zhao, Ji-Hui; Feng, Nian-Ping


    This study aimed to improve skin permeation and deposition of psoralen by using ethosomes and to investigate real-time drug release in the deep skin in rats. We used a uniform design method to evaluate the effects of different ethosome formulations on entrapment efficiency and drug skin deposition. Using in vitro and in vivo methods, we investigated skin penetration and release from psoralen-loaded ethosomes in comparison with an ethanol tincture. In in vitro studies, the use of ethosomes was associated with a 6.56-fold greater skin deposition of psoralen than that achieved with the use of the tincture. In vivo skin microdialysis showed that the peak concentration and area under the curve of psoralen from ethosomes were approximately 3.37 and 2.34 times higher, respectively, than those of psoralen from the tincture. Moreover, it revealed that the percutaneous permeability of ethosomes was greater when applied to the abdomen than when applied to the chest or scapulas. Enhanced permeation and skin deposition of psoralen delivered by ethosomes may help reduce toxicity and improve the efficacy of long-term psoralen treatment.

  19. In vitro acetylcholinesterase inhibition by psoralen using molecular docking and enzymatic studies

    Directory of Open Access Journals (Sweden)

    Gauresh Somani


    Full Text Available Introduction: Alzheimer′s disease (AD has increased at an alarming rate and is now a worldwide health problem. Inhibitors of acetylcholinesterase (AChE leading to inhibition of acetylcholine breakdown constitute the main therapeutic strategy for AD. Psoralen was investigated as inhibitor of AChE enzyme in an attempt to explore its potential for the management of AD. Materials and Methods: Psoralen was isolated from powdered Psoralea corylifolia fruits. AChE enzyme inhibitory activity of different concentrations of psoralen was investigated by use of in vitro enzymatic and molecular docking studies. Further, the enzyme kinetics were studied using Lineweaver-Burk plot. Results: Psoralen was found to inhibit AChE enzyme activity in a concentration-dependent manner. Kinetic studies showed psoralen inhibits AChE in a competitive manner. Molecular docking study revealed that psoralen binds well within the binding site of the enzyme showing interactions such as π-π stacking and hydrogen bonding with residues present therein. Conclusion: The result of AChE enzyme inhibitory activity of the psoralen in this study is promising. It could be further explored as a potential candidate for further development of new drugs against AD.

  20. Psoralen loaded liposomal nanocarriers for improved skin penetration and efficacy of topical PUVA in psoriasis. (United States)

    Doppalapudi, Sindhu; Jain, Anjali; Chopra, Dhiraj Kumar; Khan, Wahid


    Psoralen in combination with ultraviolet A radiation (PUVA) is an FDA recommended therapy for clinical application in the management of severe recalcitrant psoriasis. Psoralen acts by intercalation of DNA and upon exposure to UV-A, it forms monoadducts which in turn induce apoptosis. Poor skin deposition, weak percutaneous permeability of psoralen and adverse effects of severe burning, blisters, pigmentation associated with conventional topical psoralen vehicles hinders the therapeutic efficacy and safety of topical PUVA. The aim of the present study is to formulate psoralen loaded liposomal nanocarriers for enhanced skin penetration, safety and efficacy of topical PUVA in psoriasis. Two different liposomal compositions i.e., cationic liposomes composed of DC-Chol, cholesterol and anionic liposomes composed of egg lecithin, cholesterol, tetramyristoyl cardiolipin were prepared for the topical delivery of psoralen. Liposomal carriers were characterized with respect to size, zeta potential, entrapment efficiency, stability, in vitro drug release and in vivo studies. Both liposomes were prepared with particle size of nearly 100nm. Zeta potential and entrapment efficiency of cationic liposomes were +25.8mV, 75.12% and anionic liposomes were -28.5mV, 60.08% respectively. Liposomal dermal distribution demonstrated higher penetration of both liposomal carriers over solution. Similarly, skin permeation study indicated 5 fold increase in permeation of psoralen with liposomal carriers. Topical application of psoralen liposomal gels on imiquimod induced psoriatic plaque model reduced the symptoms of psoriasis and levels of key psoriatic cytokines such as tumor necrosis factor-α, IL-17 and IL-22. In conclusion, the developed liposomal carriers of psoralen were found to be promising and can find application for optimal safety and efficacy of topical PUVA in psoriasis. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Induction of mixed-function oxidases in mouse liver by psoralens. (United States)

    Mandula, B B; Pathak, M A; Nakayama, Y; Davidson, S J


    8-methoxypsoralen, the most widely used psoralen in photochemotherapy, was shown to induce mixed-function oxidases. Induction of mixed-function oxidases in mouse liver was examined after mice were given a single dose of one of three psoralens. 8-methoxypsoralen clearly induced p-nitroanisole O-demethylase and slightly induced aryl hydrocarbon hydroxylase. Psoralen and 4,5',8-trimethylpsoralen failed to induce either enzyme. These results represent the first enzyme induction studies on these clinically useful compounds. The studies may have relevance in understanding the clinical differences in skin photosensitizing activity and photochemotherapeutic effectiveness of the compounds in such diseases as psoriasis and vitiligo.

  2. Sensitivity of Escherichia coli acrA Mutants to Psoralen plus Near-Ultraviolet Radiation

    DEFF Research Database (Denmark)

    Hansen, M. Trier


    The sensitivity to psoralen plus near-ultraviolet radiation (PUVA) was compared in a pair of E. coli strains differing at the acrA locus. Survival was determined for both bacteria and phage λ. AcrA mutant cells were 40 times more sensitive than wild type to the lethal effect of PUVA. Free λ phage...... of radiolabelled psoralens in the mutant. Binding was increased specifically to DNA rather than to nucleic acids in general. The difference in psoralen-binding ability determined by the acrA gene persisted after permeabilizing treatment of the cells. The results suggest that the acrA mutation causes an alteration...

  3. Immunogenicity of unprocessed and photooxidized bovine and human osteochondral grafts in collagen-sensitive mice

    Directory of Open Access Journals (Sweden)

    Lehmann Paul V


    Full Text Available Abstract Background Autologous and allogeneic osteochondral grafts have been used to repair damaged or diseased cartilage. There are drawbacks to both of these methods, however. Another possible source for osteochondral grafting is photooxidized xenograft scaffolds. The purpose of this study was to evaluate the adaptive immune response to unprocessed and photooxidized xenogeneic osteochondral grafts in a collagen-sensitive mouse model. Methods Unprocessed and photooxidized bovine and human osteochondral grafts were used. The grafts were implanted subcutaneously in collagen-sensitive DBA/1LacJ mice for four or twelve weeks. ELISPOT assays were conducted with spleen cells to evaluate the number of collagen-specific T cells that produce IL-2, IL-4, IL-5 or IFN-γ. Serum was collected and ELISA assays were performed to determine the titers of collagen-specific and total IgG, IgG1, IgG2a, or IgM antibodies. Histology was conducted on the retrieved osteochondral grafts. Results Results indicated that, with respect to adaptive T cell immunity, the photooxidized bovine grafts, unprocessed human grafts and photooxidized human grafts did not induce a significant response to collagen. The unprocessed bovine grafts, however, were slightly more immunogenic, inducing a weak immune response. With respect to antibody production, the bovine grafts were less immunogenic than the human grafts. Bovine collagen-specific IgG antibodies were not induced by these grafts, but production of IgM after twelve weeks was observed with both the unprocessed and photooxidized bovine grafts. In contrast, photooxidized human osteochondral grafts induced IgG1 and IgG2a antibodies, while the unprocessed human grafts did not. Pre-existing human collagen-specific IgM antibodies were present in all mice, including sham-operated negative controls that did not receive an implant. Histological analysis revealed some degree of fibrous encapsulation and inflammatory infiltrations in both

  4. Possible mechanism of psoralen phototoxicity not involving direct interaction with DNA

    Energy Technology Data Exchange (ETDEWEB)

    Laskin, J.D.; Lee, E.; Yurkow, E.J.; Laskin, D.L.; Gallo, M.A.


    Psoralens in combination with ultraviolet light (UVA; 320-400 nm) are used in the photochemical treatment of a variety of skin diseases including vitiligo, a skin depigmentational disorder, and psoriasis, a disease of accelerated epidermal cell proliferation. Although it is generally assumed that the major site of action of the psoralens is DNA, the authors have obtained evidence that another site may be the primary target for these compounds. They have identified specific, saturable, high-affinity binding sites for 8-methoxypsoralen on HeLa cells and have detected specific binding of 8-methoxypsoralen to four other human cell lines and five mouse cell lines. In HeLa cells, specific binding is reversible and independent of the ability of the compound to intercalate into DNA. In addition, binding sites become covalently modified by the psoralen after UVA exposure. Specific binding of 8-(methyoxy-/sup 3/H)methoxypsoralen constitutes 79% of the label bound to the cells. Scatchard analysis indicated two classes of psoralen binding sites. Based on these findings, the authors hypothesize that specific binding sites for psoralens on mammalian cells mediate, at least in part, psoralen-induced phototoxicity.

  5. Evaluation of skin viability effect on ethosome and liposome-mediated psoralen delivery via cell uptake. (United States)

    Zhang, Yong-Tai; Shen, Li-Na; Wu, Zhong-Hua; Zhao, Ji-Hui; Feng, Nian-Ping


    This study investigated the effect of skin viability on its permeability to psoralen delivered by ethosomes, as compared with liposomes. With decreasing skin viability, the amount of liposome-delivered psoralen that penetrated through the skin increased, whereas skin deposition of psoralen from both ethosomes and liposomes reduced. Psoralen delivery to human-immortalized epidermal cells was more effective using liposomes, whereas delivery to human embryonic skin fibroblast cells was more effective when ethosomes were used. These findings agreed with those of in vivo studies showing that skin psoralen deposition from ethosomes and liposomes first increased and then plateaued overtime, which may indicate gradual saturation of intracellular drug delivery. It also suggested that the reduced deposition of ethosome- or liposome-delivered psoralen in skin with reduced viability may relate to reduced cellular uptake. This work indicated that the effects of skin viability should be taken into account when evaluating nanocarrier-mediated drug skin permeation. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  6. Degradation of 5-FU by means of advanced (photo)oxidation processes: UV/H2O2, UV/Fe2+/H2O2 and UV/TiO2--Comparison of transformation products, ready biodegradability and toxicity. (United States)

    Lutterbeck, Carlos Alexandre; Wilde, Marcelo Luís; Baginska, Ewelina; Leder, Christoph; Machado, Ênio Leandro; Kümmerer, Klaus


    The present study investigates the degradation of the antimetabolite 5-fluorouracil (5-FU) by three different advanced photo oxidation processes: UV/H2O2, UV/Fe(2+)/H2O2 and UV/TiO2. Prescreening experiments varying the H2O2 and TiO2 concentrations were performed in order to set the best catalyst concentrations in the UV/H2O2 and UV/TiO2 experiments, whereas the UV/Fe(2+)/H2O2 process was optimized varying the pH, Fe(2+) and H2O2 concentrations by means of the Box-Behnken design (BBD). 5-FU was quickly removed in all the irradiation experiments. The UV/Fe(2+)/H2O2 and UV/TiO2 processes achieved the highest degree of mineralization, whereas the lowest one resulted from the UV/H2O2 treatment. Six transformation products were formed during the advanced (photo)oxidation processes and identified using low and high resolution mass spectrometry. Most of them were formed and further eliminated during the reactions. The parent compound of 5-FU was not biodegraded, whereas the photolytic mixture formed in the UV/H2O2 treatment after 256 min showed a noticeable improvement of the biodegradability in the closed bottle test (CBT) and was nontoxic towards Vibrio fischeri. In silico predictions showed positive alerts for mutagenic and genotoxic effects of 5-FU. In contrast, several of the transformation products (TPs) generated along the processes did not provide indications for mutagenic or genotoxic activity. One exception was TP with m/z 146 with positive alerts in several models of bacterial mutagenicity which could demand further experimental testing. Results demonstrate that advanced treatment can eliminate parent compounds and its toxicity. However, transformation products formed can still be toxic. Therefore toxicity screening after advanced treatment is recommendable. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Catalytic photooxidation of pentachlorophenol using semiconductor nanoclusters

    Energy Technology Data Exchange (ETDEWEB)



    Pentachlorophenol (PCP) is a toxic chlorinated aromatic molecule widely used as fungicide, a bactericide and a wood preservation, and thus ubiquitous in the environment. The authors report photo-oxidation of PCP using a variety of nanosize semiconductor metal oxides and sulfides in both aqueous and polar organic solvents and compare the photo-oxidation kinetics of these nanoclusters to widely studied bulk powders like Degussa P-25 TiO{sub 2} and CdS. They study both the light intensity dependence of PCP photooxidation for nanosize SnO{sub 2} and the size dependence of PCP photooxidation for both nanosize SnO{sub 2} and MoS{sub 2}. They find an extremely strong size dependence for the latter which they attribute to its size-dependent band gap and the associated change in redox potentials due to quantum confinement of the hole-electron pair. The authors show that nanosize MoS{sub 2} with a diameter of d=3.0 nm and an absorbance edge of {approximately}450 nm is a very effective photooxidation catalyst for complete PCP mineralization, even when using only visible light irradiation.

  8. The application of psoralens to the study of DNA structure, function and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Spielmann, Peter Hans [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry


    A series of six nitroxide spin-labeled psoralens were designed, synthesized and tested as probes for DNA dynamics. The synthesis of these spin-labeled psoralen derivatives and their photoreactivity with double-stranded DNA fragments is described. The spin labels (nitroxides) were demonstrated to survive the uv irradiation required to bind the probe to the target DNA. EPR spectra of the photobound spin-labels indicate that they do not wobble with respect to the DNA on the time-scales investigated. The author has used psoralen modified DNA as a model for the study of DNA repair enzyme systems in human cell free extracts. He has shown that damage-induced DNA synthesis is associated with removal of psoralen adducts and therefore is "repair synthesis" and not an aberrant DNA synthesis reaction potentiated by deformation of the DNA by adducts. He has found that all DNA synthesis induced by psoralen monoadducts is the consequence of removal of these adducts. By the same approach he has obtained evidence that this in vitro system is capable of removing psoralen cross-links as well. Reported here are synthetic methods that make use of high intensity lasers coupled with HPLC purification to make homogeneous and very pure micromole quantities of furan-side monoadducted, cross-linked, and pyrone-side monoadducted DNA oligonucleotide. These molecules are currently being studied by NMR and X-ray crystallography. The application of the site-specifically psoralen modified oligonucleotide synthesized by these methods to the construction of substrates for the investigation of DNA repair is also discussed.

  9. Comparison of ethosomes and liposomes for skin delivery of psoralen for psoriasis therapy. (United States)

    Zhang, Yong-Tai; Shen, Li-Na; Wu, Zhong-Hua; Zhao, Ji-Hui; Feng, Nian-Ping


    Recent reports have indicated that psoriasis may be caused by malfunctioning dermal immune cells, and psoralen ultraviolet A (PUVA) is an effective treatment for this chronic disease. However, conventional topical formulations achieve poor drug delivery across patches of psoriasis to their target sites. The present study describes the development of a novel psoralen transdermal delivery system employing ethosomes, flexible vesicles that can penetrate the stratum corneum and target deep skin layers. An in vitro skin permeation study showed that the permeability of psoralen-loaded ethosomes was superior to that of liposomes. Using ethosomes, psoralen transdermal flux and skin deposition were 38.89±0.32 μg/cm(2)/h and 3.87±1.74 μg/cm(2), respectively, 3.50 and 2.15 times those achieved using liposomes, respectively. The ethosomes and liposomes were found to be safe following daily application to rat skin in vivo, for 7 days. The ethosomes showed better biocompatibility with human embryonic skin fibroblasts than did an equivalent ethanol solution, indicating that the phosphatidylcholine present in ethosome vesicles improved their biocompatibility. These findings indicated that ethosomes could potentially improve the dermal and transdermal delivery of psoralen and possibly of other drugs requiring deep skin delivery. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Probing the binding mode of psoralen to calf thymus DNA. (United States)

    Zhou, Xiaoyue; Zhang, Guowen; Wang, Langhong


    The binding properties between psoralen (PSO) and calf thymus DNA (ctDNA) were predicted by molecular docking, and then determined with the use of UV-vis absorption, fluorescence, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy, coupled with DNA melting and viscosity measurements. The data matrix obtained from UV-vis spectra was resolved by multivariate curve resolution-alternating least squares (MCR-ALS) approach. The pure spectra and the equilibrium concentration profiles for PSO, ctDNA and PSO-ctDNA complex extracted from the highly overlapping composite response were obtained simultaneously to evaluate the PSO-ctDNA interaction. The intercalation mode of PSO binding to ctDNA was supported by the results from the melting studies, viscosity measurements, iodide quenching and fluorescence polarization experiments, competitive binding investigations and CD analysis. The molecular docking prediction showed that the specific binding most likely occurred between PSO and adenine bases of ctDNA. FT-IR spectra studies further confirmed that PSO preferentially bound to adenine bases, and this binding decreased right-handed helicity of ctDNA and enhanced the degree of base stacking with the preservation of native B-conformation. The calculated thermodynamic parameters indicated that hydrogen bonds and van der Waals forces played a major role in the binding process. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Photo-oxidation of IgG1 and Model Peptides: Detection and Analysis of Triply Oxidized His and Trp Side Chain Cleavage Products. (United States)

    Bane, Jessica; Mozziconacci, Olivier; Yi, Li; Wang, Y John; Sreedhara, Alavattam; Schöneich, Christian


    Triply oxidized histidine in an IgG1 monoclonal antibody was noticed when exposed to ICH light conditions. In order to understand the role of light source, irradiation wavelengths and primary sequence, specifically those of a nearby tryptophan, we synthesized and exposed several peptides to ICH light conditions and analyzed the products using LC-MS analysis. Protein and peptide samples were photo-irradiated under ICH conditions as well as with monochromatic light at λ = 254 nm and analyzed using either LTQ Orbitrap or a LTQ-FT ion cyclotron resonance mass spectrometer respectively. A triply oxidized His residue was detected along with a second doubly oxidized His residue in an IgG1. Both of these oxidized His residues are located near Trp residues. In order to investigate the role of Trp photosensitization in His oxidation we synthesized model peptides and Ala mutants. Peptides exposed to ICH light stress conditions revealed a small percent of triply oxidized His in the Trp-containing peptide sequences but not in their corresponding Ala mutants. The differences in product formation under different photo-irradiation conditions underline the importance of light source, irradiation wavelengths and primary sequence in the photosensitivity of proteins.

  12. Psoralen Inactivation of Viruses: A Process for the Safe Manipulation of Viral Antigen and Nucleic Acid

    Directory of Open Access Journals (Sweden)

    Katherine Schneider


    Full Text Available High consequence human pathogenic viruses must be handled at biosafety level 2, 3 or 4 and must be rendered non-infectious before they can be utilized for molecular or immunological applications at lower biosafety levels. Here we evaluate psoralen-inactivated Arena-, Bunya-, Corona-, Filo-, Flavi- and Orthomyxoviruses for their suitability as antigen in immunological processes and as template for reverse transcription PCR and sequencing. The method of virus inactivation using a psoralen molecule appears to have broad applicability to RNA viruses and to leave both the particle and RNA of the treated virus intact, while rendering the virus non-infectious.

  13. Cyclohexene photo-oxidation over vanadia catalyst analyzed by time resolvedATR-FT-IT spectroscopy

    NARCIS (Netherlands)

    Mul, Guido; Wasylenko, W.; Sameh Hamdy, M.; Frei, H.


    Vanadia was incorporated in the 3-D mesoporous material TUD-1 with a loading of 2% w/w vanadia. The performance in the selective photo-oxidation of liquid cyclohexene was investigated using ATR-FT-IR spectroscopy. Under continuous illumination at 458 nm a significant amount of product,

  14. Comparison of Chemical Changes During Photooxidation of Polypropylene Film and Filament Containing Phthalocyanine Pigment

    Directory of Open Access Journals (Sweden)

    Z. Ahmadi


    Full Text Available Photooxidation as an important process, which significantly affects the service life of the polypropylene products, has been the subject of much theoretical and experimental study. Pigments used often change the light stabilities of polypropylene. Out-door applications of pigmented polypr-opylene are now increasingly developed in products such as artificial grass. The aim of this work is to examine the effect of photo-oxidation on the structure of isotactic polypropylene (iPP in film and filament forms, where phthalocyanine pigment is used. For production of films and filaments, iPP granules with MFI 25 g/10min were used, with and without phthalocyanine pigment. Samples were exposed to xenon lamp for various time lengths. The extent of the changes in chemical and structural parameters was examined by differential scanning calorimetry, Fourier transform infrared spectroscopy and wide angle x-ray diffraction. The results show that carbonyl and hydroperoxide indices increase during the exposure to the radiation. The changes in melting points of the samples were not significant after irradiation process. The effects of phthalocyanine pigment in the photooxidation of filmand filament were different. Crystalline fractions of the non-pigmented filament samples decreased during the irradiation time while increased in film samples. Build up of hydroperoxide and carbonyl group in filament was higher than in film samples; that could be due to the differences in structural parameters. Crystallinity variations during photooxidation are related to the nucleation effect of the pigment, chemical crystallization and phase transformation.

  15. Evaluation of the effects of photooxidized Echis carinatus venom on learning, memory and stress

    Directory of Open Access Journals (Sweden)

    C. M. Reddy


    Full Text Available Snake venoms are a mixture of complex proteins, which have many physical and pharmacological properties. Photochemical detoxification has been suggested to generate photooxidized Echis carinatus venom product (POECVP. Antigenically-active photooxidized species of Echis carinatus venom could be obtained by exposing the venom to ultraviolet radiation (UVR in the presence of methylene blue. The aim of the present study was to evaluate the effects of POECVP on learning, memory and stress in rats. Detoxification of the photooxidized venom was evident since the POECVP-treated group had longer survival time than the group of mice treated with Echis carinatus venom product (ECVP following intraperitoneal and intracerebral injections. Photooxidized Echis carinatus venom product showed antidepressant activity by prolonging sleep onset and shortening the duration of pentobarbitone-induced hypnosis in mice. In single and chronic dose studies with rats, we observed that POECVP significantly decreased the time needed to reach food in T-maze, shortened transfer latency in elevated plus-maze, and decreased immobility time in forced swim test. We concluded that although there is a possibility of employing POECVP in the treatment of depressive and chronic degenerative illnesses as a nonherbal and nonsynthetic alternative for patients not responding to the available therapy, further investigation is still needed.

  16. Targeted gene correction using psoralen, chlorambucil and camptothecin conjugates of triplex forming peptide nucleic acid (PNA)

    DEFF Research Database (Denmark)

    Birkedal, Henrik; Nielsen, Peter E


    Gene correction activation effects of a small series of triplex forming peptide nucleic acid (PNA) covalently conjugated to the DNA interacting ligands psoralen, chlorambucil and camptothecin targeted proximal to a stop codon mutation in an EGFP reporter gene were studied. A 15-mer homopyrimidine...

  17. Isolation and purification of psoralen and isopsoralen and their efficacy and safety in the treatment of osteosarcoma in nude rats. (United States)

    Lu, Honghui; Zhang, Lihai; Liu, Daohong; Tang, Peifu; Song, Feixiang


    Modern studies have shown that psoralen has a significant inhibitory effect on tumor growth in a variety of animals and humans. To obtain coumarin compounds - psoralen and isopsoralen - from traditional Chinese medicine Psoralea corylifolia L. using chromatographic techniques and isolation and purification methods, and to observe the transplanted tumor growth inhibitory effects and adverse reactions of psoralen and isopsoralen in nude rats with osteosarcoma. Dried ripe fruits of Psoralea corylifolia L. were taken as the raw material to prepare crude extract of Psoralea corylifolia L. by ethanol reflux method. Column chromatography was used to isolate the crude extract; compounds were structurally identified based on (1)H-NMR, (13)C-NMR spectra, the two compounds were identified as psoralen andisopsoralen, and their contents were 99.7% and 99.6, respectively. Nude rat model of osteosarcoma was established; the rats were randomized into: normal saline group, psoralen low- and high-dose groups, isopsoralen low- and high-dose groups, and cisplatin group. Osteosarcoma volume and weight inhibition rates in nude rats in each group were observed; radioimmunoassay was used to determine the serum alkaline phosphatase activity; peripheral blood cell and bone marrow nucleated cell counts were determined; light microscopy was used to observe heart, liver, spleen, lung, kidney, and tumor histopathology; and electron microscopy was used to observe the fine structure of tumor cells. Tumor volume inhibition rates were 43.75% and 40.18%, respectively, in the psoralen and isopsoralen low-dose groups, and tumor weight inhibition rates were 38.83% and 37.77%. Tumor volume inhibition rates were 67.86% and 66.96%, respectively, in the psoralen and isopsoralen high-dose groups, and tumor weight inhibition rates were 49.47% and 47.87%. Psoralen and ispsoralen markedly lowered serum AKP level. Psoralen and isopsoralen induced apoptosis or necrosis of osteosarcoma. After administration of

  18. Mechanisms Underlying the Antiproliferative and Prodifferentiative Effects of Psoralen on Adult Neural Stem Cells via DNA Microarray

    Directory of Open Access Journals (Sweden)

    You Ning


    Full Text Available Adult neural stem cells (NSCs persist throughout life to replace mature cells that are lost during turnover, disease, or injury. The investigation of NSC creates novel treatments for central nervous system (CNS injuries and neurodegenerative disorders. The plasticity and reparative potential of NSC are regulated by different factors, which are critical for neurological regenerative medicine research. We investigated the effects of Psoralen, which is the mature fruit of Psoralea corylifolia L., on NSC behaviors and the underlying mechanisms. The self-renewal and proliferation of NSC were examined. We detected neuron- and/or astrocyte-specific markers using immunofluorescence and Western blotting, which could evaluate NSC differentiation. Psoralen treatment significantly inhibited neurosphere formation in a dose-dependent manner. Psoralen treatment increased the expression of the astrocyte-specific marker but decreased neuron-specific marker expression. These results suggested that Psoralen was a differentiation inducer in astrocyte. Differential gene expression following Psoralen treatment was screened using DNA microarray and confirmed by quantitative real-time PCR. Our microarray study demonstrated that Psoralen could effectively regulate the specific gene expression profile of NSC. The genes involved in the classification of cellular differentiation, proliferation, and metabolism, the transcription factors belonging to Ets family, and the hedgehog pathway may be closely related to the regulation.

  19. Development and in vitro assessment of psoralen and resveratrol co-loaded ultradeformable liposomes for the treatment of vitiligo. (United States)

    Doppalapudi, Sindhu; Mahira, Shaheen; Khan, Wahid


    Vitiligo is a de-pigmenting skin disorder characterized by white patches on skin due to partial or complete loss of melanocytes. Psoralen in combination with ultraviolet-A (PUVA) acts by stimulation of melanin content and tyrosinase activity in melanocytes. Resveratrol, a sirtuin activator and a potential anti-oxidant reduce oxidative stress which is one of the triggering factors for initiation of vitiligo. Despite their therapeutic activity, weak percutaneous permeability of psoralen and poor solubility of resveratrol hinders their effective topical administration. The aim of present study is to formulate ultradeformable liposomes (UDL) co-loaded with psoralen and resveratrol for evaluation of PUVA and anti-oxidant combination in vitiligo treatment. For this purpose, UDL composed of DC-Chol, cholesterol and sodium deoxy cholate were prepared for their co-delivery. Liposomal carriers were characterized and evaluated for their efficacy using B16F10 cell line. Free radical scavenging potential was also determined for these carriers by in vitro anti-oxidant assays. Optimal co-loaded UDL with particle size ranging from 120 to 130nm, zeta potential of +46.2mV, entrapment efficiency of 74.09% (psoralen) and 76.91% (resveratrol) were obtained. Compared to control, co-loaded UDL showed significant stimulation of melanin and tyrosinase activity with major contribution of psoralen. Further, co-loaded UDL also exhibited potential free radical scavenging activity where resveratrol played a key role. Hence, psoralen and resveratrol co-loaded UDL acts in vitiligo through dual mechanisms of action viz., stimulation of melanin and tyrosinase activity as well as by anti-oxidant activity. These findings indicate that psoralen and resveratrol co-loaded UDL has the promising therapeutic potential for the treatment of vitiligo. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Study of photo-oxidative reactivity of sunscreening agents based on photo-oxidation of uric acid by kinetic Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Moradmand Jalali, Hamed; Bashiri, Hadis, E-mail:; Rasa, Hossein


    In the present study, the mechanism of free radical production by light-reflective agents in sunscreens (TiO{sub 2}, ZnO and ZrO{sub 2}) was obtained by applying kinetic Monte Carlo simulation. The values of the rate constants for each step of the suggested mechanism have been obtained by simulation. The effect of the initial concentration of mineral oxides and uric acid on the rate of uric acid photo-oxidation by irradiation of some sun care agents has been studied. The kinetic Monte Carlo simulation results agree qualitatively with the existing experimental data for the production of free radicals by sun care agents. - Highlights: • The mechanism and kinetics of uric acid photo-oxidation by irradiation of sun care agents has been obtained by simulation. • The mechanism has been used for free radical production of TiO{sub 2} (rutile and anatase), ZnO and ZrO{sub 2}. • The ratios of photo-activity of ZnO to anastase, rutile and ZrO have been obtained. • By doubling the initial concentrations of mineral oxide, the rate of reaction was doubled. • The optimum ratio of initial concentration of mineral oxides to uric acid has been obtained.

  1. Phototoxic effects of Hypericum extract in cultures of human keratinocytes compared with those of psoralen. (United States)

    Bernd, A; Simon, S; Ramirez Bosca, A; Kippenberger, S; Diaz Alperi, J; Miquel, J; Villalba Garcia, J F; Pamies Mira, D; Kaufmann, R


    Extracts of Hypericum perforatum (St. John's wort) are used in the treatment of depression. They contain the plant pigment hypericin and hypericin derivates. These compounds have light-dependent activities. In order to estimate the potential risk of phototoxic skin damage during antidepressive therapy, we investigated the phototoxic activity of hypericin extract using cultures of human keratinocytes and compared it with the effect of the well-known phototoxic agent psoralen. The absorbance spectrum of our Hypericum extract revealed maxima in the whole UV range and in parts of the visible range. We cultivated human keratinocytes in the presence of different Hypericum concentrations and irradiated the cells with 150 mJ/cm2 UVB, 1 J/cm2 UVA or 3 h with a white light of photon flux density 2.6 mumol m-2 s-1. The determination of the bromodeoxyuridine incorporation rate showed a concentration- and light-dependent decrease in DNA synthesis with high hypericin concentrations (> or = 50 micrograms/mL) combined with UVA or visible light radiation. In the case of UVB irradiation a clear phototoxic cell reaction was not detected. We found phototoxic effects even with 10 ng/mL psoralen using UVA with the same study design as in the case of the Hypericum extract. These results confirm the phototoxic activity of Hypericum extract on human keratinocytes. However, the blood levels that are to be expected during antidepressive therapy are presumably too low to induce phototoxic skin reactions.

  2. Orally administered Polypodium leucotomos extract decreases psoralen-UVA-induced phototoxicity, pigmentation, and damage of human skin

    NARCIS (Netherlands)

    Middelkamp-Hup, Maritza A.; Pathak, Madhu A.; Parrado, Concepcion; Garcia-Caballero, Tomas; Rius-Díaz, Francisca; Fitzpatrick, Thomas B.; González, Salvador


    BACKGROUND: The use of psoralen-UVA (PUVA) in patients of skin phototype I to II is limited by side effects of acute phototoxicity and possible long-term carcinogenesis. OBJECTIVE: We sought to assess oral Polypodium leucotomos (PL) extract in decreasing PUVA-induced phototoxicity of human skin on a

  3. Chamber simulation of photooxidation of dimethyl sulfide and isoprene in the presence of NOx

    Directory of Open Access Journals (Sweden)

    M. Jang


    Full Text Available To improve the model prediction for the formation of H2SO4 and methanesulfonic acid (MSA, aerosol-phase reactions of gaseous dimethyl sulfide (DMS oxidation products [e.g., dimethyl sulfoxide (DMSO] in aerosol have been included in the DMS kinetic model with the recently reported gas-phase reactions and their rate constants. To determine the rate constants of aerosol-phase reactions of both DMSO and its major gaseous products [e.g., dimethyl sulfone (DMSO2 and methanesulfinic acid (MSIA], DMSO was photooxidized in the presence of NOx using a 2 m3 Teflon film chamber. The rate constants tested in the DMSO kinetic mechanisms were then incorporated into the DMS photooxidation mechanism. The model simulation using the newly constructed DMS oxidation mechanims was compared to chamber data obtained from the phototoxiation of DMS in the presence of NOx. Within 120-min simulation, the predicted concentrations of MSA increase by 200–400% and those of H2SO4, by 50–200% due to aerosol-phase chemistry. This was well substantiated with experimental data. To study the effect of coexisting volatile organic compounds, the photooxidation of DMS in the presence of isoprene and NOx has been simulated using the newly constructed DMS kinetic model integrated with the Master Chemical Mechanism (MCM for isoprene oxidation, and compared to chamber data. With the high concentrations of DMS (250 ppb and isoprene (560–2248 ppb, both the model simulation and experimental data showed an increase in the yields of MSA and H2SO4 as the isoprene concentration increased.

  4. Using Limes and Synthetic Psoralens to Enhance Solar Disinfection of Water (SODIS): A Laboratory Evaluation with Norovirus, Escherichia coli, and MS2


    Harding, Alexander S.; Schwab, Kellogg J.


    We investigated the use of psoralens and limes to enhance solar disinfection of water (SODIS) using an UV lamp and natural sunlight experiments. SODIS conditions were replicated using sunlight, 2 L polyethylene terephthalate (PET) bottles, and tap water with Escherichia coli, MS2 bacteriophage, and murine norovirus (MNV). Psoralens and lime acidity both interact synergistically with UV radiation to accelerate inactivation of microbes. Escherichia coli was ablated > 6.1 logs by SODIS + Lime Sl...

  5. Photo-oxidation of proteins and its role in cataractogenesis

    DEFF Research Database (Denmark)

    Davies, Michael Jonathan; Truscott, R J


    state (triplet) molecular oxygen by either protein-bound, or other, chromophores. The basic principles behind these mechanisms of photo-oxidation of amino acids, peptides and proteins and the potential selectivity of damage are discussed. Emphasis is placed primarily on the intermediates...

  6. Secondary organic aerosol from atmospheric photooxidation of indole (United States)

    Montoya-Aguilera, Julia; Horne, Jeremy R.; Hinks, Mallory L.; Fleming, Lauren T.; Perraud, Véronique; Lin, Peng; Laskin, Alexander; Laskin, Julia; Dabdub, Donald; Nizkorodov, Sergey A.


    Indole is a heterocyclic compound emitted by various plant species under stressed conditions or during flowering events. The formation, optical properties, and chemical composition of secondary organic aerosol (SOA) formed by low-NOx photooxidation of indole were investigated. The SOA yield (1. 3 ± 0. 3) was estimated from measuring the particle mass concentration with a scanning mobility particle sizer (SMPS) and correcting it for wall loss effects. The high value of the SOA mass yield suggests that most oxidized indole products eventually end up in the particle phase. The SOA particles were collected on filters and analysed offline with UV-vis spectrophotometry to measure the mass absorption coefficient (MAC) of the bulk sample. The samples were visibly brown and had MAC values of ˜ 2 m2 g-1 at λ = 300 nm and ˜ 0. 5 m2 g-1 at λ = 400 nm, comparable to strongly absorbing brown carbon emitted from biomass burning. The chemical composition of SOA was examined with several mass spectrometry methods. Direct analysis in real-time mass spectrometry (DART-MS) and nanospray desorption electrospray high-resolution mass spectrometry (nano-DESI-HRMS) were both used to provide information about the overall distribution of SOA compounds. High-performance liquid chromatography, coupled to photodiode array spectrophotometry and high-resolution mass spectrometry (HPLC-PDA-HRMS), was used to identify chromophoric compounds that are responsible for the brown colour of SOA. Indole derivatives, such as tryptanthrin, indirubin, indigo dye, and indoxyl red, were found to contribute significantly to the visible absorption spectrum of indole SOA. The potential effect of indole SOA on air quality was explored with an airshed model, which found elevated concentrations of indole SOA during the afternoon hours contributing considerably to the total organic aerosol under selected scenarios. Because of its high MAC values, indole SOA can contribute to decreased visibility and poor air

  7. Iron and oxygen isotope fractionation during iron UV photo-oxidation: Implications for early Earth and Mars (United States)

    Nie, Nicole X.; Dauphas, Nicolas; Greenwood, Richard C.


    Banded iron formations (BIFs) contain appreciable amounts of ferric iron (Fe3+). The mechanism by which ferrous iron (Fe2+) was oxidized into Fe3+ in an atmosphere that was globally anoxic is highly debated. Of the three scenarios that have been proposed to explain BIF formation, photo-oxidation by UV photons is the only one that does not involve life (the other two are oxidation by O2 produced by photosynthesis, and anoxygenic photosynthesis whereby Fe2+ is directly used as electron donor in place of water). We experimentally investigated iron and oxygen isotope fractionation imparted by iron photo-oxidation at a pH of 7.3. The iron isotope fractionation between precipitated Fe3+-bearing lepidocrocite and dissolved Fe2+ follows a Rayleigh distillation with an instantaneous 56Fe/54Fe fractionation factor of + 1.2 ‰. Such enrichment in the heavy isotopes of iron is consistent with the values measured in BIFs. We also investigated the nature of the mass-fractionation law that governs iron isotope fractionation in the photo-oxidation experiments (i.e., the slope of the δ56Fe-δ57Fe relationship). The experimental run products follow a mass-dependent law corresponding to the high-T equilibrium limit. The fact that a ∼3.8 Gyr old BIF sample (IF-G) from Isua (Greenland) falls on the same fractionation line confirms that iron photo-oxidation in the surface layers of the oceans was a viable pathway to BIF formation in the Archean, when the atmosphere was largely transparent to UV photons. Our experiments allow us to estimate the quantum yield of the photo-oxidation process (∼0.07 iron atom oxidized per photon absorbed). This yield is used to model iron oxidation on early Mars. As the photo-oxidation proceeds, the aqueous medium becomes more acidic, which slows down the reaction by changing the speciation of iron to species that are less efficient at absorbing UV-photons. Iron photo-oxidation in centimeter to meter-deep water ponds would take months to years to

  8. Stable Carbon Isotope Ratios of Phenolic Compounds in Secondary Particulate Organic Matter Formed by Photooxidation of Toluene

    CERN Document Server

    Irei, Satoshi; Huang, Lin; Auld, Janeen; Collin, Fabrice; Hastie, Donald


    Compound-specific stable carbon isotope ratios for phenolic compounds in secondary particulate organic matter (POM) formed by photooxidation of toluene were studied. Secondary POM generated by photooxidation of toluene using a continuous-flow reactor and an 8 cubic meter indoor smog chamber was collected, and then extracted with acetonitrile. Eight phenolic compounds were identified in the extracts by a gas chromatograph coupled with a mass spectrometer, and their compound-specific stable carbon isotope ratios were determined by a gas chromatograph coupled with a combustion furnace followed by an isotope ratio mass spectrometer. The majority of the products, including methylnitrophenols and methylnitrocatechols, were isotopically depleted by 5 to 6 permil compared to the initial isotope ratio for toluene, whereas the isotope ratio for 4_nitrophenol remained the same as the initial isotope ratio for toluene. Based on the reaction mechanisms postulated in literature, stable carbon isotope ratios of these produc...

  9. Rescue of Mitomycin C- or Psoralen-Inactivated Micrococcus Radiodurans by Additional Exposure to Radiation or Alkylating Agents

    DEFF Research Database (Denmark)

    Hansen, M. Trier


    The processing of damaged DNA was altered in a mitomycin C-sensitive mutant (mtcA) of Micrococcus radiodurans. Even though the mutant retained resistance to 254-nm UV radiation, it did not, in contrast to the wild-type strain, show any excessive DNA degradation or cell death when incubated...... in the mtcA background. In this strain, additional damage infficted upon the cellular DNA effected a massive rescue of cells previously inactivated by mitomycin C. Rescue was provoked by ionizing radiation, by UV light, or by simple alkylating agents. Cells treated with psoralen plus near-UV radiation could...... interstrand cross-links produced by mitomycin C or psoralen plus near-UV light, but induced only by the more abundant number of damages produced by radiation or simple alkylating agents....

  10. Heterogeneous Catalysis by Tetraethylammonium Tetrachloroferrate of the Photooxidation of Toluene by Visible and Near-UV Light

    Directory of Open Access Journals (Sweden)

    Kelsie R. Barnard


    Full Text Available Titanium dioxide is the most extensively used heterogeneous catalyst for the photooxidation of toluene and other hydrocarbons, but it has low utility for the synthesis of benzyl alcohol, of which little is produced, or benzaldehyde, due to further oxidation to benzoic acid and cresol, among other oxidation products, and eventually complete mineralization to CO2. Et4N[FeCl4] functions as a photocatalyst through the dissociation of chlorine atoms, which abstract hydrogen from toluene, and the photooxidation of toluene proceeds only as far as benzyl alcohol and benzaldehyde. Unlike TiO2, which requires ultraviolet (UV irradiation, Et4N[FeCl4] catalyzes the photooxidation of toluene with visible light alone. Even under predominantly UV irradiation, the yield of benzyl alcohol plus benzaldehyde is greater with Et4N[FeCl4] than with TiO2. Et4N[FeCl4] photocatalysis yields benzyl chloride as a side product, but it can be minimized by restricting irradiation to wavelengths above 360 nm and by the use of long irradiation times. The photonic efficiency of oxidation in one experiment was found to be 0.042 mol/einstein at 365 nm. The use of sunlight as the irradiation source was explored.

  11. Photo-oxidation from mode-locked laser exposure to hTERT-RPE1 cells (United States)

    Denton, Michael L.; Eikum, Debbie M.; Noojin, Gary D.; Stolarski, David J.; Glickman, Randolph D.; Rockwell, Benjamin A.


    Human retinal pigment epithelial (RPE) cells (hTERT-RPE1) were used to detect photo-oxidation products generated from chronic NIR (810 nm) laser exposure. Exposure of a discrete area within cell monolayers provided a means of distinguishing fluorescence above background levels. Oxidative stress was detected using the fluorescent dye H2DCF-DA and its analog CM-H2DCF-DA. Fluorescence was detected in cells exposed to mode-locked (76 MHz, ~160 femtoseconds) but not CW laser exposure. Detection of photo-oxidation from the mode-locked laser was dependent upon radiant exposure, but only if irradiance was greater than a threshold value. The CM-H2DCF-DA dye proved a more sensitive indicator of oxidation than H2DCF-DA, and the radiant exposure threshold for detection was dependent upon dye concentration. No oxidation was detected from CW exposures (using the most sensitive fluorescent dye conditions) when using 3 times the irradiance, and 10 times the radiant exposure needed to detect fluorescence from mode-locked exposure.

  12. Minimizing photooxidation in pasteurized milk by optimizing light transmission properties of green polyethylene films. (United States)

    Intawiwat, N; Wold, J P; Skaret, J; Rukke, E O; Pettersen, M K


    The effect of different amounts of transmitted green light on photooxidation in pasteurized milk was studied. Five different green films produced with combinations of pigments and additives to minimize exposure to harmful wavelengths with regard to photosensitizers (400-450 and 600-650 nm) were evaluated. In addition, a non-colored transparent film and an orange film were compared with 1 selected green film. Pasteurized milk (3.9% fat) was packed in an air atmosphere and exposed to light for 14, 20, 26, and 32 h at 4 °C under the different films. Samples stored in the dark were control samples. The results showed that the most-effective green film had low overall light transmission, and also almost completely blocked light wavelengths shorter than 450 nm and wavelengths longer than 600 nm, which prevented photooxidation of riboflavin and chlorophyllic compounds. Chlorophyll degradation was highly correlated with sensory properties (coefficient of determination = 0.80-0.94). To preserve milk quality, total blocking of all visible light would be preferable. If total blocking is not feasible, then light transmission for wavelength below 450 nm and above 650 nm should be minimized (e.g., less than 5%). The newly developed green film can be used as a prototype for protection of dairy products to reduce the degradation of photosensitizers. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Degradation of 5-FU by means of advanced (photo)oxidation processes: UV/H{sub 2}O{sub 2}, UV/Fe{sup 2+}/H{sub 2}O{sub 2} and UV/TiO{sub 2} — Comparison of transformation products, ready biodegradability and toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Lutterbeck, Carlos Alexandre, E-mail: [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Scharnhorststraße 1/C13, DE-21335 Lüneburg (Germany); Graduate Program in Environmental Technology, Universidade de Santa Cruz do Sul — UNISC, Av. Independência, 2293, CEP 96815-900 Santa Cruz do Sul, Rio Grande do Sul (Brazil); Wilde, Marcelo Luís, E-mail: [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Scharnhorststraße 1/C13, DE-21335 Lüneburg (Germany); Baginska, Ewelina, E-mail: [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Scharnhorststraße 1/C13, DE-21335 Lüneburg (Germany); Leder, Christoph, E-mail: [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Scharnhorststraße 1/C13, DE-21335 Lüneburg (Germany); Machado, Ênio Leandro, E-mail: [Graduate Program in Environmental Technology, Universidade de Santa Cruz do Sul — UNISC, Av. Independência, 2293, CEP 96815-900 Santa Cruz do Sul, Rio Grande do Sul (Brazil); and others


    The present study investigates the degradation of the antimetabolite 5-fluorouracil (5-FU) by three different advanced photo oxidation processes: UV/H{sub 2}O{sub 2}, UV/Fe{sup 2+}/H{sub 2}O{sub 2} and UV/TiO{sub 2}. Prescreening experiments varying the H{sub 2}O{sub 2} and TiO{sub 2} concentrations were performed in order to set the best catalyst concentrations in the UV/H{sub 2}O{sub 2} and UV/TiO{sub 2} experiments, whereas the UV/Fe{sup 2+}/H{sub 2}O{sub 2} process was optimized varying the pH, Fe{sup 2+} and H{sub 2}O{sub 2} concentrations by means of the Box–Behnken design (BBD). 5-FU was quickly removed in all the irradiation experiments. The UV/Fe{sup 2+}/H{sub 2}O{sub 2} and UV/TiO{sub 2} processes achieved the highest degree of mineralization, whereas the lowest one resulted from the UV/H{sub 2}O{sub 2} treatment. Six transformation products were formed during the advanced (photo)oxidation processes and identified using low and high resolution mass spectrometry. Most of them were formed and further eliminated during the reactions. The parent compound of 5-FU was not biodegraded, whereas the photolytic mixture formed in the UV/H{sub 2}O{sub 2} treatment after 256 min showed a noticeable improvement of the biodegradability in the closed bottle test (CBT) and was nontoxic towards Vibrio fischeri. In silico predictions showed positive alerts for mutagenic and genotoxic effects of 5-FU. In contrast, several of the transformation products (TPs) generated along the processes did not provide indications for mutagenic or genotoxic activity. One exception was TP with m/z 146 with positive alerts in several models of bacterial mutagenicity which could demand further experimental testing. Results demonstrate that advanced treatment can eliminate parent compounds and its toxicity. However, transformation products formed can still be toxic. Therefore toxicity screening after advanced treatment is recommendable. - Highlights: • Full primary elimination of 5-FU was

  14. Photooxidation and Phototoxicity of pi-extended squaraines. (United States)

    Rapozzi, Valentina; Beverina, Luca; Salice, Patrizio; Pagani, Giorgio A; Camerin, Monica; Xodo, Luigi E


    This paper describes the synthesis of pi-extended squaraines and their photooxidation properties and gives an in-depth characterization of these molecules as photosensitizing agents. Squaraines show a strong absorption in the tissue transparency window (600-800 nm), and upon irradiation, they undergo a photooxidation process, leading to the formation of peroxide and hydroperoxide radicals according to a type I radical chain process. Confocal laser microscopy demonstrates that the designed squaraines efficiently internalize in the cytoplasm and not in the nucleus of the cell. In the dark, they are scarcely cytotoxic, but after irradition, they promote a strong dose-dependent phototoxic effect in four different cancer cells. In HeLa and MCF-7 cells, squaraines 4 and 5, thanks to their hydrocarbon tails, associate to the membranes and induce lipid peroxidation, as indicated by a marked increase of malonyldialdehyde after photodynamic treatment, in agreement with in vitro photooxidation studies. FACS, caspase-3/7 assays and time-lapse microscopy demonstrate that the designed squaraines cause cell death primarily by necrosis.

  15. Psoralen plus ultraviolet A (PUVA soaks and UVB TL01 treatment for chronic hand dermatoses

    Directory of Open Access Journals (Sweden)

    Lisbeth Jensen


    Full Text Available Chronic eczematous hand dermatoses with and without contact allergies are complex diseases, which makes it a challenge to select the best treatment and obtain an optimal patient experience and a satisfactory treatment result. The aim of this study was to evaluate retrospectively the clinical effect and patient experience of local treatment with psoralen plus ultraviolet A (PUVA soaks and TL01 phototherapy for severe chronic hand dermatoses, and also to evaluate the quality of life for the subgroup of patients with allergic contact dermatitis including Compositae allergy. A retrospective evaluation of results for 94 consecutive patients having received a total of 121 treatment courses with local PUVA soaks or TL01 phototherapy for one of the following diagnoses (n=number of treatment courses: psoriasis (n=19, hyperkeratotic hand eczema (n=27, Pustulosis Palmoplantaris (PPP (n=22, vesicular eczema (n=16, Compositae dermatitis (n=24, and allergic contact dermatitis (n=13. Moreover, semi-structured interviews with 6 selected patients having multiple contact allergies including Compositae allergy were used to evaluate quality of life. As a result, we found that PUVA soaks has good effect in patients with psoriasis and hyperkeratotic hand eczema and local phototherapy for chronic hand dermatoses is a useful treatment option in selected cases.

  16. Selective Photooxidation of a Mustard-Gas Simulant Catalyzed by a Porphyrinic Metal-Organic Framework. (United States)

    Liu, Yangyang; Howarth, Ashlee J; Hupp, Joseph T; Farha, Omar K


    The photooxidation of a mustard-gas simulant, 2-chloroethyl ethyl sulfide (CEES), is studied using a porphyrin-based metal-organic framework (MOF) catalyst. At room temperature and neutral pH value, singlet oxygen is generated by PCN-222/MOF-545 using an inexpensive and commercially available light-emitting diode. The singlet oxygen produced by PCN-222/MOF-545 selectively oxidizes CEES to the comparatively nontoxic product 2-chloroethyl ethyl sulfoxide (CEESO) without formation of the highly toxic sulfone product. In comparison to current methods, which utilize hydrogen peroxide as an oxidizing agent, this is a more realistic, convenient, and effective method for mustard-gas detoxification. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Methods of Functionalization of Carbon Nanotubes by Photooxidation (United States)

    Lebron-Colon, Marisabel (Inventor); Meador, Michael A. (Inventor)


    A method of photooxidizing carbon nanotubes, such as single-walled and multi-walled carbon nanotubes. The nanotubes are purified and dispersed in a solvent, such as n-methyl pyrrolidinone or dimethylformamide. A singlet oxygen sensitizer like Rose Bengal is added to the solution. Oxygen gas is continuously supplied while irradiating the solution while irradiating the solution with ultraviolet light to produce singlet oxygen to oxidize the single-walled carbon nanotubes. Advantageously, the method significantly increases the level of oxidation compared with prior art methods.

  18. Catalyst-free photooxidation of triarylphosphines under aerobic conditions

    Directory of Open Access Journals (Sweden)

    Aishun Ding


    Full Text Available A new method for the photooxidation of triarylphosphines into the corresponding oxides is developed. In this new protocol, neither a catalyst nor an additive is required. The greenest oxidant, oxygen in air atmosphere, is used. After a short period of photo irradiation at rt, stoichiometric amounts of the oxides can be easily afforded by simply recycling the solvent under vacuum. No waste is formed in the whole process of this reaction. The substrate scope of this reaction is broad, showing very good application prospects in both organic chemistry and industrial processes.

  19. Photooxidation of Some Metallocenes in a Polymer Matrix

    Directory of Open Access Journals (Sweden)

    B. Mallik


    Full Text Available The changes in the electronic absorption spectra (UV-Vis of some metallocene-doped poly(methyl methacrylate (PMMA thin films containing chloroform molecules as impurities were studied after photoexcitation in the nitrogen atmosphere. Photoexcitations were made by monochromatic radiation (using a Xe-lamp source and a monochromator at an interval of few nanometers in the spectral range 210-750 nm. The changes in spectra were studied as a function of photoexcitation time (duration, amount of metallocene in the film and the amount of chloroform molecules present in the film. Occurrence of photoinduced charge-transfer between some metallocenes and chloroform molecules confined in the PMMA thin films was observed, which indicated photooxidation of the metallocenes in the polymer matrix. Photoresponse in the case of ferrocene derivatives was observed to decrease with the increase in the value of para- Hammett constant for the substituent attached to the ferrocene unit and also with increasing half-wave potential for the ferrocene derivatives. Photoeffects on the metallocenes having different central metal atom were studied and it was noticed that the photoeffects on the metallocenes with "18 valence electrons", as in ferrocene and ruthenocene, favored the occurrence of photoinduced charge-transfer between the metallocene and chloroform molecules present in a PMMA film. The photooxidation of a metallocene in a PMMA thin film resulted in an enhanced photoconductivity of the polymeric film.

  20. Surface Properties of Photo-Oxidized Bituminous Coals: Final report

    Energy Technology Data Exchange (ETDEWEB)



    Natural weathering has a detrimental effect on the hydrophobic nature of coal, which in turn can influence clean-coal recovery during flotation. Few techniques are available that can establish the quality of coal surfaces and that have a short analysis time to provide input for process control. Luminescence emissions which can be quantified with an optical microscope and photometer system, are measurably influenced by degree of weathering as well as by mild storage deterioration. In addition, it has been shown that when vitrinite is irradiated with a relatively high intensity flux of violet- or ultraviolet- light in the presence of air, photo-oxidation of the surface occurs. The combination of measuring the change in luminescence emission intensity with degree of surface oxidation provided the impetus for the current investigation. The principal aim of this research was to determine whether clear correlations could be established among surface oxygen functionality, hydrophobicity induced by photo-oxidation, and measurements of luminescence intensity and alteration. If successful, the project would result in quantitative luminescence techniques based on optical microscopy that would provide a measure of the changes in surface properties as a function of oxidation and relate them to coal cleanability. Two analytical techniques were designed to achieve these goals. Polished surfaces of vitrain bands or a narrow size fraction of powdered vitrain concentrates were photo-oxidized using violet or ultraviolet light fluxes and then changes in surface properties and chemistry were measured using a variety of near-surface analytical techniques. Results from this investigation demonstrate that quantitative luminescence intensity measurements can be performed on fracture surfaces of bituminous rank coals (vitrains) and that the data obtained do reveal significant variations depending upon the level of surface oxidation. Photo-oxidation induced by violet or ultraviolet light

  1. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of a health claim related to a combination of lycopene, vitamin E, lutein and selenium and protection of the skin from UV-induced (including photo-oxidative) damage pursuant to Article 13

    DEFF Research Database (Denmark)

    Tetens, Inge

    related to a combination of lycopene, vitamin E, lutein and selenium and protection of the skin from UV-induced (including photo-oxidative) damage. The Panel considers that the combination of lycopene, vitamin E, lutein and selenium is sufficiently characterised. The claimed effect refers to the photo...... could be drawn from this study for the scientific substantiation of the claim. The Panel concludes that a cause and effect relationship has not been established between the consumption of a combination of lycopene, vitamin E, lutein and selenium and protection of the skin from UV-induced (including...

  2. Photooxidative treatment of sulfurous water for its potabilization. (United States)

    Hernández, Fernando; Geissler, Gunther


    The feasibility of potabilization of sulfurous water was investigated by photochemical oxidation processes using a batch photoreactor and a continuous-flow photoreactor, equipped with UV lamps of 1000 W and 1500 W, respectively. Additionally, two advanced processes of oxidation were applied i.e. with a use of a UV light/H2O2/air and UV light/H2O2/O3/air. These two processes were compared for their efficiency to the direct oxidation process where ozone is used in the absence of UV light. Results obtained for both advanced processes showed better oxidation than takes place by ozone in the absence of UV light. After the photooxidation processes, different processes for the absorption or precipitation of sulfates were investigated to comply with the World Health Organization (WHO) norm that demands a limit of water. Additionally, reverse osmosis was simulated using Osmonics Inc. software to predict the feasibility of lowering the salt concentration below WHO limits.

  3. Photooxidation Behavior of a LDPE/Clay Nanocomposite Monitored through Creep Measurements

    Directory of Open Access Journals (Sweden)

    Francesco Paolo La Mantia


    Full Text Available Creep behavior of polymer nanocomposites has not been extensively investigated so far, especially when its effects are combined with those due to photooxidation, which are usually studied in completely independent ways. In this work, the photooxidation behavior of a low density polyethylene/organomodified clay nanocomposite system was monitored by measuring the creep curves obtained while subjecting the sample to the combined action of temperature, tensile stress, and UV radiation. The creep curves of the irradiated samples were found to be lower than those of the non-irradiated ones and progressively diverging, because of the formation of branching and cross-linking due to photooxidation. This was further proved by the decrease of the melt index and the increase of the intrinsic viscosity; at the same time, the formation of carbonyl groups was observed. This behavior was more observable in the nanocomposite sample, because of its faster photooxidation kinetics.

  4. Long term in-vivo studies of a photo-oxidized bovine osteochondral transplant in sheep

    Directory of Open Access Journals (Sweden)

    Zlinszky Kati


    Full Text Available Abstract Background Articular cartilage has limited capacity to repair. Defects greater than 3 mm heal with formation of inferior fibrous cartilage. Therefore, many attempts have been made to find the ideal graft for larger cartilage lesions. Different grafts, such as untreated or cryopreserved osteochondral transplants, have been used with variable success. Methods Photo-oxidized osteochondral grafts were implanted in both femoral condyles of one ovine knee. Untreated xenogeneic and autogeneic grafts served as controls. Three groups of 8 sheep each were formed and they were sacrificed 6, 12 or 18 months after surgery. Results The macroscopic evaluation of the condyle and graft showed a well-maintained cartilage surface in most grafts at all time points. However, the host cartilage matrix deteriorated considerably in all xenogeneic, most autogeneic and fewer of the photo-oxidized grafts at 12 and 18 months, respectively. The blue colour of the photo-oxidized grafts resulting from the process of photo-oxidation was visible in all grafts at 6 months, had diminished at 12 months and had completely disappeared at 18 months after surgery. Histologically a loss of matrix staining was almost never noticed in untreated xenografts, transiently at 6 months in photo-oxidized grafts and increased at 12 and 18 months. Fusion between graft and host cartilage could be seen in photo-oxidized grafts at 12 and 18 months, but was never seen in autografts and xenografts. Conclusions The photo-oxidation of osteochondral grafts and its use as transplant appears to have a beneficial effect on cartilage and bone remodelling. Osteochondral grafts pre-treated with photo-oxidation may be considered for articular cartilage replacement and therefore may delay artificial joint replacements in human patients.

  5. Psoralen-mediated virus photoinactivation in platelet concentrates: enhanced specificity of virus kill in the absence of shorter UVA wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Margolis-Nunno, Henrietta; Robinson, Richard; Horowitz, Bernard; Ben-Hur, Ehud [New York Blood Center, NY (United States); Geacintov, N.E. [New York Univ., NY (United States). Dept. of Chemistry


    Treatments with psoralens and long-wavelength ultraviolet radiation (UVA, 320-400 nm; PUVA) have shown efficacy for virus sterilization of platelet concentrates (PC). We have employed the psoralen derivative 4`-aminomethyl-4,5`,8-trimethylpsoralen (AMT), and have found that platelet integrity is best preserved when rutin, a flavonoid that quenches multiple reactive oxygen species, is present during AMT/UVA treatment of PC. In this report, we examine the effects of different UVA spectra under our standard PC treatment conditions (i.e. 50 {mu}g/mL AMT, 0.35 mM rutin and 38 J/cm{sup 2} UVA). Added vesicular stomatitis virus (VSV; {>=} 5.5 log{sub 10}) was completely inactivated with the simultaneous maintenance of the platelet aggregation response (> 90% of control) when a UVA light source with transmission mainly between 360 and 370 nm (narrow UVA1) was used. In contrast, with a broad-band UVA (320-400 nm; broad UVA) light source, the aggregation response was greatly compromised (< 50% of control) with only a minor increase in the rate of VSV kill. With this lamp, platelet function could be improved to about 75% of the control by adding a long-pass filter, which reduced the transmission of shorter ({<=} 345 nm) UVA wavelengths (340-400 nm; UVA1). At equivalent levels of virus kill, aggregation function was always best preserved when narrow UVA1 was used for PUVA treatment. Even in the absence of AMT, and with or without rutin present, narrow UVA1 irradiation was better tolerated by platelets than was broad UVA. (author).

  6. VUV photo-oxidation of gaseous benzene combined with ozone-assisted catalytic oxidation: Effect on transition metal catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Haibao, E-mail: [School of Environmental Science and Engineering, Sun Yat-Sen University (China); Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University) (China); Lu, Haoxian; Zhan, Yujie; Liu, Gaoyuan; Feng, Qiuyu; Huang, Huiling; Wu, Muyan; Ye, Xinguo [School of Environmental Science and Engineering, Sun Yat-Sen University (China)


    Graphical abstract: Mn nanoparticles are highly dispersed on ZSM-5 and most efficient in benzene degradation in the VUV-OZCO process. - Highlights: • Vacuum UV irradiation is well combined with O{sub 3} catalytic oxidation. • O{sub 3} byproducts was used to enhance catalytic oxidation of VOCs. • Mn/ZSM-5 achieved the best catalytic activity for benzene degradation. - Abstract: Volatile organic compounds (VOCs) cause the major air pollution concern. In this study, a series of ZSM-5 supported transition metals were prepared by impregnation method. They were combined with vacuum UV (VUV) photo-oxidation in a continuous-flow packed-bed reactor and used for the degradation of benzene, a typical toxic VOCs. Compared with VUV photo-oxidation alone, the introduction of catalysts can greatly enhance benzene oxidation under the help of O{sub 3}, the by-products from VUV irradiation, via ozone-assisted catalytic oxidation (OZCO). The catalytic activity of transition metals towards benzene oxidation followed the order: Mn > Co > Cu > Ni > Fe. Mn achieved the best catalytic activity due to the strongest capability for O{sub 3} catalytic decomposition and utilization. Benzene and O{sub 3} removal efficiency reached as high as 97% and 100% after 360 min, respectively. O{sub 3} was catalytically decomposed, generating highly reactive oxidants such as ·OH and ·O for benzene oxidation.

  7. Chilling-enhanced photooxidation: evidence for the role of singlet oxygen and superoxide in the breakdown of pigments and endogenous antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Wise, R.R.; Naylor, A.W.


    Chilling temperatures (5/sup 0/C) and high irradiance (1000 microeinsteins per square meter per second) were used to induce photooxidation in detached leaves of cucumber (Cucumis sativus L.), a chilling-sensitive plant. Chlorophyll a, chlorophyll b, ..beta.. carotene, and three xanthophylls were degraded in a light-dependent fashion at essentially the same rate. Lipid peroxidation (measured as ethane evolution) showed an O/sub 2/ dependency. The levels of three endogenous antioxidants, ascorbate, reduced glutathione, and ..cap alpha.. tocopherol, all showed an irradiance-dependent decline. ..cap alpha..-Tocopherol was the first antioxidant affected and appeared to be the only antioxidant that could be implicated in long-term protection of the photosynthetic pigments. Results from the application of antioxidants having relative selectivity for /sup 1/O/sub 2/, O/sub 2//sup +/, or OH indicated that both /sup 1/O/sub 2/ and O/sub 2//sup -/ were involved in the chilling- and light-induced lipid peroxidation which accompanied photooxidation. Application of D/sub 2/O (which enhances the lifetime of /sup 1/O/sub 2/) corroborated these results. Chilling under high light produced no evidence of photooxidative damage in detached leaves of chilling-resistant pea (Pisum sativum L.). Their results suggest a fundamental difference in the ability of pea to reduce the destructive effects of free-radical and /sup 1/O/sub 2/ production in chloroplasts during chilling in high light.

  8. Cyclohexene Photo-oxidation over Vanadia Catalyst Analyzed by Time Resolved ATR-FT-IR Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Frei, Heinz; Mul, Guido; Wasylenko, Walter; Hamdy, M. Sameh; Frei, Heinz


    Vanadia was incorporated in the 3-dimensional mesoporous material TUD-1 with a loading of 2percent w/w vanadia. The performance in the selective photo-oxidation of liquid cyclohexene was investigated using ATR-FT-IR spectroscopy. Under continuous illumination at 458 nm a significant amount of product, i.e. cyclohexenone, was identified. This demonstrates for the first time that hydroxylated vanadia centers in mesoporous materials can be activated by visible light to induce oxidation reactions. Using the rapid scan method, a strong perturbation of the vanadyl environment could be observed in the selective oxidation process induced by a 458 nm laser pulse of 480 ms duration. This is proposed to be caused by interaction of the catalytic centre with a cyclohexenyl hydroperoxide intermediate. The restoration of the vanadyl environment could be kinetically correlated to the rate of formation of cyclohexenone, and is explained by molecular rearrangement and dissociation of the peroxide to ketone and water. The ketone diffuses away from the active center and ATR infrared probing zone, resulting in a decreasing ketone signal on the tens of seconds time scale after initiation of the photoreaction. This study demonstrates the high potential of time resolved ATR FT-IR spectroscopy for mechanistic studies of liquid phase reactions by monitoring not only intermediates and products, but by correlating the temporal behavior of these species to molecular changes of the vanadyl catalytic site.

  9. Using limes and synthetic psoralens to enhance solar disinfection of water (SODIS): a laboratory evaluation with norovirus, Escherichia coli, and MS2. (United States)

    Harding, Alexander S; Schwab, Kellogg J


    We investigated the use of psoralens and limes to enhance solar disinfection of water (SODIS) using an UV lamp and natural sunlight experiments. SODIS conditions were replicated using sunlight, 2 L polyethylene terephthalate (PET) bottles, and tap water with Escherichia coli, MS2 bacteriophage, and murine norovirus (MNV). Psoralens and lime acidity both interact synergistically with UV radiation to accelerate inactivation of microbes. Escherichia coli was ablated > 6.1 logs by SODIS + Lime Slurry and 5.6 logs by SODIS + Lime Juice in 30-minute solar exposures, compared with a 1.5 log reduction with SODIS alone (N = 3; P 3.9 logs by SODIS + Lime Slurry, 1.9 logs by SODIS + Lime Juice, and 1.4 logs by SODIS in 2.5-hour solar exposures (N = 3; P SODIS, with SODIS against human norovirus should be investigated further.

  10. Allelism of Saccharomyces cerevisiae gene PSO10, involved in error-prone repair of psoralen-induced DNA damage, with SUMO ligase-encoding MMS21. (United States)

    Hoch, Nícolas C; Santos, Rafael S; Rosa, Renato M; Machado, Roseane M; Saffi, Jenifer; Brendel, Martin; Henriques, João A P


    In order to extend the understanding of the genetical and biochemical basis of photo-activated psoralen-induced DNA repair in the yeast Saccharomyces cerevisiae we have identified and cloned 10 pso mutants. Here, we describe the phenotypic characterization and molecular cloning of the pso10-1 mutant which is highly sensitive to photoactivated psoralens, UV(254) (nm) radiation and the alkylating agent methylmethane sulphonate. The pso10-1 mutant allele also confers a block in the mutagenic response to photoactivated psoralens and UV(254) (nm) radiation, and homoallelic diploids do not sporulate. Molecular cloning using a yeast genomic library, sequence analysis and genetic complementation experiments proved pso10-1 to be a mutant allele of gene MMS21 that encodes a SUMO ligase involved in the sumoylation of several DNA repair proteins. The ORF of pso10-1 contains a single nucleotide C-->T transition at position 758, which leads to a change in amino acid sequence from serine to phenylalanine [S253F]. Pso10-1p defines a leaky mutant phenotype of the essential MMS21 gene, and as member of the Smc5-Smc6 complex, still has some essential functions that allow survival of the mutant. DNA repair via translesion synthesis is severely impaired as the pso10-1 mutant allele confers severely blocked induced forward and reverse mutagenesis and shows epistatic interaction with a rev3Delta mutant allele. By identifying the allelism of PSO10 and MMS21 we demonstrate the need of a fully functional Smc5-Smc6 complex for a WT-like adequate repair of photoactivated psoralen-induced DNA damage in yeast.

  11. Modelling of the photooxidation of toluene: conceptual ideas for validating detailed mechanisms

    Directory of Open Access Journals (Sweden)

    V. Wagner


    Full Text Available Toluene photooxidation is chosen as an example to examine how simulations of smog-chamber experiments can be used to unravel shortcomings in detailed mechanisms and to provide information on complex reaction systems that will be crucial for the design of future validation experiments. The mechanism used in this study is extracted from the Master Chemical Mechanism Version 3 (MCM v3 and has been updated with new modules for cresol and g-dicarbonyl chemistry. Model simulations are carried out for a toluene-NOx experiment undertaken at the European Photoreactor (EUPHORE. The comparison of the simulation with the experimental data reveals two fundamental shortcomings in the mechanism: OH production is too low by about 80%, and the ozone concentration at the end of the experiment is over-predicted by 55%. The radical budget was analysed to identify the key intermediates governing the radical transformation in the toluene system. Ring-opening products, particularly conjugated g-dicarbonyls, were identified as dominant radical sources in the early stages of the experiment. The analysis of the time evolution of radical production points to a missing OH source that peaks when the system reaches highest reactivity. First generation products are also of major importance for the ozone production in the system. The analysis of the radical budget suggests two options to explain the concurrent under-prediction of OH and over-prediction of ozone in the model: 1 missing oxidation processes that produce or regenerate OH without or with little NO to NO2 conversion or 2 NO3 chemistry that sequesters reactive nitrogen oxides into stable nitrogen compounds and at the same time produces peroxy radicals. Sensitivity analysis was employed to identify significant contributors to ozone production and it is shown how this technique, in combination with ozone isopleth plots, can be used for the design of validation experiments.

  12. Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO2

    Directory of Open Access Journals (Sweden)

    Z. Yu


    Full Text Available The photocatalytic ability of airborne mineral dust particles is known to heterogeneously promote SO2 oxidation, but prediction of this phenomenon is not fully taken into account by current models. In this study, the Atmospheric Mineral Aerosol Reaction (AMAR model was developed to capture the influence of air-suspended mineral dust particles on sulfate formation in various environments. In the model, SO2 oxidation proceeds in three phases including the gas phase, the inorganic-salted aqueous phase (non-dust phase, and the dust phase. Dust chemistry is described as the absorption–desorption kinetics of SO2 and NOx (partitioning between the gas phase and the multilayer coated dust. The reaction of absorbed SO2 on dust particles occurs via two major paths: autoxidation of SO2 in open air and photocatalytic mechanisms under UV light. The kinetic mechanism of autoxidation was first leveraged using controlled indoor chamber data in the presence of Arizona Test Dust (ATD particles without UV light, and then extended to photochemistry. With UV light, SO2 photooxidation was promoted by surface oxidants (OH radicals that are generated via the photocatalysis of semiconducting metal oxides (electron–hole theory of ATD particles. This photocatalytic rate constant was derived from the integration of the combinational product of the dust absorbance spectrum and wave-dependent actinic flux for the full range of wavelengths of the light source. The predicted concentrations of sulfate and nitrate using the AMAR model agreed well with outdoor chamber data that were produced under natural sunlight. For seven consecutive hours of photooxidation of SO2 in an outdoor chamber, dust chemistry at the low NOx level was attributed to 55 % of total sulfate (56 ppb SO2, 290 µg m−3 ATD, and NOx less than 5 ppb. At high NOx ( >  50 ppb of NOx with low hydrocarbons, sulfate formation was also greatly promoted by dust chemistry, but it was suppressed by

  13. Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO2 (United States)

    Yu, Zechen; Jang, Myoseon; Park, Jiyeon


    The photocatalytic ability of airborne mineral dust particles is known to heterogeneously promote SO2 oxidation, but prediction of this phenomenon is not fully taken into account by current models. In this study, the Atmospheric Mineral Aerosol Reaction (AMAR) model was developed to capture the influence of air-suspended mineral dust particles on sulfate formation in various environments. In the model, SO2 oxidation proceeds in three phases including the gas phase, the inorganic-salted aqueous phase (non-dust phase), and the dust phase. Dust chemistry is described as the absorption-desorption kinetics of SO2 and NOx (partitioning between the gas phase and the multilayer coated dust). The reaction of absorbed SO2 on dust particles occurs via two major paths: autoxidation of SO2 in open air and photocatalytic mechanisms under UV light. The kinetic mechanism of autoxidation was first leveraged using controlled indoor chamber data in the presence of Arizona Test Dust (ATD) particles without UV light, and then extended to photochemistry. With UV light, SO2 photooxidation was promoted by surface oxidants (OH radicals) that are generated via the photocatalysis of semiconducting metal oxides (electron-hole theory) of ATD particles. This photocatalytic rate constant was derived from the integration of the combinational product of the dust absorbance spectrum and wave-dependent actinic flux for the full range of wavelengths of the light source. The predicted concentrations of sulfate and nitrate using the AMAR model agreed well with outdoor chamber data that were produced under natural sunlight. For seven consecutive hours of photooxidation of SO2 in an outdoor chamber, dust chemistry at the low NOx level was attributed to 55 % of total sulfate (56 ppb SO2, 290 µg m-3 ATD, and NOx less than 5 ppb). At high NOx ( > 50 ppb of NOx with low hydrocarbons), sulfate formation was also greatly promoted by dust chemistry, but it was suppressed by the competition between NO2 and SO2

  14. Photooxidation of herbicide amitrole in the presence of fulvic acid. (United States)

    Pozdnyakov, Ivan P; Sherin, Peter S; Salomatova, Victoria A; Parkhats, Marina V; Grivin, Vjacheslav P; Dzhagarov, Boris M; Bazhin, Nikolai M; Plyusnin, Victor F


    Fulvic acid (Henan ChangSheng Corporation) photoinduced degradation of non-UVA-absorbing herbicide amitrole (3-amino-1,2,4-triazole, AMT) as a way for its removal from polluted water was investigated in details. It was shown that the main primary species generated by fulvic acid under UVA radiation, triplet state and hydrated electron, are not directly involved in the herbicide degradation. AMT decays in reactions with secondary intermediates, reactive oxygen species, formed in reactions of the primary ones with dissolved oxygen. Singlet oxygen is responsible for 80% of herbicide oxidation, and •OH and O2-• radicals-for the remaining 20% of AMT. It was found that quantum yield of AMT photodegradation (ϕ 365nm) decreases linearly from 2.2 × 10-3 to 1.2 × 10-3 with the increase of fulvic acid concentration from 1.1 to 30 mg L-1. On the contrary, the increase of AMT concentration from 0.8 to 25 mg L-1 leads to practically linear growth of ϕ 365nm value from 1.8 × 10-4 to 4 × 10-3. Thus, the fulvic acid exhibits a good potential as UVA photooxidizer of organic pollutants sensitive to the singlet oxygen (ϕ 532nm(1O2) = 0.025 at pH 6.5).

  15. Role of methyl group number on SOA formation from aromatic hydrocarbons photooxidation under low NOx conditions (United States)

    Li, L.; Tang, P.; Nakao, S.; Chen, C.-L.; Cocker, D. R., III


    Substitution of methyl groups onto the aromatic ring determines the SOA formation from the aromatic hydrocarbon precursor. This study links the number of methyl groups on the aromatic ring to SOA formation from aromatic hydrocarbons photooxidation under low NOx conditions (HC / NO > 10 ppb C : ppb). Aromatic hydrocarbons with increasing numbers of methyl groups are systematically studied. SOA formation from pentamethylbenzene and hexamethylbenzene are reported for the first time. A decreasing SOA yield with increasing number of methyl groups is observed. Linear trends are found in both f44 vs. f43 and O / C vs. H / C for SOA from aromatic hydrocarbons with zero to six methyl groups. An SOA oxidation state predictive method based on benzene is used to examine the effect of added methyl groups on aromatic oxidation under low NOx conditions. Further, the impact of methyl group number on density and volatility of SOA from aromatic hydrocarbons is explored. Finally, a mechanism for methyl group impact on SOA formation is suggested. Overall, this work suggests as more methyl groups are attached on the aromatic ring, SOA products from these aromatic hydrocarbons become less oxidized per mass/carbon.

  16. High formation of secondary organic aerosol from the photo-oxidation of toluene

    Directory of Open Access Journals (Sweden)

    L. Hildebrandt


    Full Text Available Toluene and other aromatics have long been viewed as the dominant anthropogenic secondary organic aerosol (SOA precursors, but the SOA mass yields from toluene reported in previous studies vary widely. Experiments conducted in the Carnegie Mellon University environmental chamber to study SOA formation from the photo-oxidation of toluene show significantly larger SOA production than parameterizations employed in current air-quality models. Aerosol mass yields depend on experimental conditions: yields are higher under higher UV intensity, under low-NOx conditions and at lower temperatures. The extent of oxidation of the aerosol also varies with experimental conditions, consistent with ongoing, progressive photochemical aging of the toluene SOA. Measurements using a thermodenuder system suggest that the aerosol formed under high- and low-NOx conditions is semi-volatile. These results suggest that SOA formation from toluene depends strongly on ambient conditions. An approximate parameterization is proposed for use in air-quality models until a more thorough treatment accounting for the dynamic nature of this system becomes available.

  17. Explicit modelling of SOA formation from α-pinene photooxidation: sensitivity to vapour pressure estimation

    Directory of Open Access Journals (Sweden)

    R. Valorso


    Full Text Available The sensitivity of the formation of secondary organic aerosol (SOA to the estimated vapour pressures of the condensable oxidation products is explored. A highly detailed reaction scheme was generated for α-pinene photooxidation using the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A. Vapour pressures (Pvap were estimated with three commonly used structure activity relationships. The values of Pvap were compared for the set of secondary species generated by GECKO-A to describe α-pinene oxidation. Discrepancies in the predicted vapour pressures were found to increase with the number of functional groups borne by the species. For semi-volatile organic compounds (i.e. organic species of interest for SOA formation, differences in the predicted Pvap range between a factor of 5 to 200 on average. The simulated SOA concentrations were compared to SOA observations in the Caltech chamber during three experiments performed under a range of NOx conditions. While the model captures the qualitative features of SOA formation for the chamber experiments, SOA concentrations are systematically overestimated. For the conditions simulated, the modelled SOA speciation appears to be rather insensitive to the Pvap estimation method.

  18. SU-E-T-93: Activation of Psoralen at Depth Using Kilovoltage X-Rays: Physics Considerations in Implementing a New Teletherapy Paradigm

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, J; Yoon, P; Liu, L; Alcorta, D; Spector, N; Oldham, M [Duke University Medical Center, Durham, NC (United States); Nolan, M; Gieger, T [North Carolina State University, Raleigh, NC (United States); Walder, H; Fathi, Z; Beyer, W [Immunolight LLC, Detroit, MI (United States)


    Purpose: Psoralen is a UV-light activated anti-cancer biotherapeutic used for treating skin lesions (PUVA) and advanced cutaneous T-cell lymphoma (ECP). To date psoralen has not been used to treat deep seated tumors due to difficulty in generating UV-light at depth. We recently demonstrated psoralen activation at depth by introducing energy converting particles that absorb kV x-ray radiation and re-emit UV-light. Our in-vitro work found that 0.2–1Gy using 40–100kVp x-rays combined with psoralen and particles can induce a substantial apoptotic response beyond that expected from the sum of individual components. In preparation for a phase I clinical trial of canine companion animals, we address the physics and dosimetry considerations for applying this new teletherapy paradigm to an in-vivo setting. Methods: The kV on-board imaging (OBI) system mounted on a medical linear accelerator (Varian) was commissioned to deliver the prescribed dose (0.6Gy) using 80 and 100kVp. Dosimetric measurements included kVp, HVL, depth dose, backscatter factors, collimator and phantom scatter factors, field size factors, and blade leakage. Absolute dosimetry was performed following AAPM TG61 recommendations and verified with an independent kV dose meter. We also investigated collimated rotational delivery to minimize skin dose using simple dose calculations on homogeneous cylindrical phantoms. Results: Single beam delivery is feasible for shallow targets (<5cm) without exceeding skin tolerance, while a rotational delivery may be utilized for deeper targets; skin dose is ∼75% of target dose for 80kVp collimated rotational delivery to a 3cm target within a 20cm phantom. Heat loading was tolerable; 0.6Gy to 5cm can be delivered before the anode reaches 75% capacity. Conclusion: KV teletherapy for Psoralen activation in deep seated tissue was successfully commissioned for a Varian OBI machine for use in a phase I clinical trial in canines. Future work will use Monte Carlo dosimetry to

  19. Effect of humidity on the composition of isoprene photooxidation secondary organic aerosol

    Directory of Open Access Journals (Sweden)

    T. B. Nguyen


    Full Text Available The effect of relative humidity (RH on the composition and concentrations of gas-phase products and secondary organic aerosol (SOA generated from the photooxidation of isoprene under high-NOx conditions was investigated. Experiments were performed with hydrogen peroxide as the OH precursor and in the absence of seed aerosol. The relative yields of most gas-phase products were the same regardless of initial water vapor concentration with exception of hydroxyacetone and glycolaldehyde, which were considerably affected by RH. A significant change was observed in the SOA composition, with many unique condensed-phase products formed under humid (90 % RH vs. dry (<2 % RH conditions, without any detectable effect on the rate and extent of the SOA mass growth. There is a 40 % reduction in the number and relative abundance of distinct particle-phase nitrogen-containing organic compounds (NOC detected by high resolution mass spectrometry. The suppression of condensation reactions, which produce water as a product, is the most important chemical effect of the increased RH. For example, the total signal from oligomeric esters of 2-methylglyceric acid was reduced by about 60 % under humid conditions and the maximum oligomer chain lengths were reduced by 7–11 carbons. Oligomers formed by addition mechanisms, without direct involvement of water, also decreased at elevated RH but to a much smaller extent. The observed reduction in the extent of condensation-type oligomerization at high RH may have substantial impact on the phase characteristics and hygroscopicity of the isoprene aerosol. The reduction in the amount of organic nitrates in the particle phase has implications for understanding the budget of NOC compounds.

  20. Photooxidation of Ammonia on TiO2 Surfaces as a Source of Nitrogen Oxides in the Troposphere (United States)

    Raff, J.; Kebede, M. A.; Scharko, N. K.; Donaldson, M. C.


    Ammonia is an important air pollutant in urban and rural areas alike, whose main fate is dry and wet deposition to surfaces. While reactions with OH radical in the gas phase are slow, our work shows that photochemical uptake of ammonia onto surfaces containing semiconductor minerals such as TiO2 is efficient and yields significant amounts of gas phase NO2, NO, and HONO. A coated wall flow tube coupled to a chemical ionization mass spectrometer (CIMS) and a chemiluminescence analyzer was used to study the product yields of HONO and NOx under atmospherically relevant conditions, while diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) was used to elucidate the mechanism of ammonia photooxidation on anatase surfaces. Our results show that photochemical processing of ammonia is likely a source of reactive oxides of nitrogen in urban areas where surfaces commonly contain TiO2, and in areas impacted by mineral dust and ammonia emissions.

  1. Catalytic photooxidation of alcohols by an unsymmetrical tetra(pyridyl)pyrazine-bridged dinuclear Ru complex. (United States)

    Chen, Weizhong; Rein, Francisca N; Scott, Brian L; Rocha, Reginaldo C


    The dinuclear complexes [(tpy)Ru(tppz)Ru(bpy)(L)](n+) (where L is Cl(-) or H(2)O, tpy and bpy are the terminal ligands 2,2':6',2''-terpyridine and 2,2'-bipyridine, and tppz is the bridging backbone 2,3,5,6-tetrakis(2-pyridyl)pyrazine) were prepared and structurally and electronically characterized. The mononuclear complexes [(tpy)Ru(tppz)](2+) and [(tppz)Ru(bpy)(L)](m+) were also prepared and studied for comparison. The proton-coupled, multi-electron photooxidation reactivity of the aquo dinuclear species was shown through the photocatalytic dehydrogenation of a series of primary and secondary alcohols. Under simulated solar irradiation and in the presence of a sacrificial electron acceptor, the photoactivated chromophore-catalyst complex (in aqueous solutions at room temperature and ambient pressure conditions) can perform the visible-light-driven conversion of aliphatic and benzylic alcohols into the corresponding carbonyl products (i.e., aldehydes or ketones) with 100% product selectivity and several tens of turnover cycles, as probed by NMR spectroscopy and gas chromatography. Moreover, for aliphatic substrates, the activity of the photocatalyst was found to be highly selective toward secondary alcohols, with no significant product formed from primary alcohols. Comparison of the activity of this tppz-bridged complex with that of the analogue containing a back-to-back terpyridine bridge (tpy-tpy, i.e., 6',6''-bis(2-pyridyl)-2,2':4',4'':2'',2'''-quaterpyridine) demonstrated that the latter is a superior photocatalyst toward the oxidation of alcohols. The much stronger electronic coupling with significant delocalization across the strongly electron-accepting tppz bridge facilitates charge trapping between the chromophore and catalyst centers and therefore is presumably responsible for the decreased catalytic performance. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. The RecQ helicase RECQL5 participates in psoralen-induced interstrand cross-link repair (United States)

    Bohr, Vilhelm A.


    Interstrand cross-links (ICLs) are very severe lesions as they are absolute blocks of replication and transcription. This property of interstrand cross-linking agents has been exploited clinically for the treatment of cancers and other diseases. ICLs are repaired in human cells by specialized DNA repair pathways including components of the nucleotide excision repair pathway, double-strand break repair pathway and the Fanconi anemia pathway. In this report, we identify the role of RECQL5, a member of the RecQ family of helicases, in the repair of ICLs. Using laser-directed confocal microscopy, we demonstrate that RECQL5 is recruited to ICLs formed by trioxalen (a psoralen-derived compound) and ultraviolet irradiation A. Using single-cell gel electrophoresis and proliferation assays, we identify the role of RECQL5 in the repair of ICL lesions. The domain of RECQL5 that recruits to the site of ICL was mapped to the KIX region between amino acids 500 and 650. Inhibition of transcription and of topoisomerases did not affect recruitment, which was inhibited by DNA-intercalating agents, suggesting that the DNA structure itself may be responsible for the recruitment of RECQL5 to the sites of ICLs. PMID:23715498

  3. A new low cost wide-field illumination method for photooxidation of intracellular fluorescent markers.

    Directory of Open Access Journals (Sweden)

    Manoel da Silva Filho

    Full Text Available Analyzing cell morphology is crucial in the fields of cell biology and neuroscience. One of the main methods for evaluating cell morphology is by using intracellular fluorescent markers, including various commercially available dyes and genetically encoded fluorescent proteins. These markers can be used as free radical sources in photooxidation reactions, which in the presence of diaminobenzidine (DAB forms an opaque and electron-dense precipitate that remains localized within the cellular and organelle membranes. This method confers many methodological advantages for the investigator, including absence of photo-bleaching, high visual contrast and the possibility of correlating optical imaging with electron microscopy. However, current photooxidation techniques require the continuous use of fluorescent or confocal microscopes, which wastes valuable mercury lamp lifetime and limits the conversion process to a few cells at a time. We developed a low cost optical apparatus for performing photooxidation reactions and propose a new procedure that solves these methodological restrictions. Our "photooxidizer" consists of a high power light emitting diode (LED associated with a custom aluminum and acrylic case and a microchip-controlled current source. We demonstrate the efficacy of our method by converting intracellular DiI in samples of developing rat neocortex and post-mortem human retina. DiI crystals were inserted in the tissue and allowed to diffuse for 20 days. The samples were then processed with the new photooxidation technique and analyzed under optical microscopy. The results show that our protocols can unveil the fine morphology of neurons in detail. Cellular structures such as axons, dendrites and spine-like appendages were well defined. In addition to its low cost, simplicity and reliability, our method precludes the use of microscope lamps for photooxidation and allows the processing of many labeled cells simultaneously in relatively

  4. Sensitized photooxidation of phenols by fulvic acid and in natural waters

    Energy Technology Data Exchange (ETDEWEB)

    Faust, B.C.; Hoigne, J.


    In addition to singlet oxygen, irradiation of fulvic acid solutions and lake water with UV and visible light (lambda > 315 nm) produces another transient oxidant species. This transient oxidant (probably an organic peroxy radical) is derived from natural dissolved organic material (DOM) and controls DOM-sensitized photooxidations of various alkylphenols. On the basis of kinetic data for the transient oxidant, DOM-sensitized photooxidation half-lives of alkylphenols are estimated to range from 1 day to several months in middle-latitude shallow surface waters.

  5. Role of magnesium in carbon partitioning and alleviating photooxidative damage. (United States)

    Cakmak, Ismail; Kirkby, Ernest A


    effectively delayed by partial shading of the leaf blade, although the Mg concentrations in different parts of the leaf blade were unaffected by shading. The results indicate that photooxidative damage contributes to development of leaf chlorosis under Mg deficiency, suggesting that plants under high-light conditions have a higher physiological requirement for Mg. Maintenance of a high Mg nutritional status of plants is, thus, essential in the avoidance of ROS generation, which occurs at the expense of inhibited phloem export of sugars and impairment of CO2 fixation, particularly under high-light conditions.

  6. Aqueous phase processing of secondary organic aerosol from isoprene photooxidation

    Directory of Open Access Journals (Sweden)

    Y. Liu


    Full Text Available Transport of reactive air masses into humid and wet areas is highly frequent in the atmosphere, making the study of aqueous phase processing of secondary organic aerosol (SOA very relevant. We have investigated the aqueous phase processing of SOA generated from gas-phase photooxidation of isoprene using a smog chamber. The SOA collected on filters was extracted by water and subsequently oxidized in the aqueous phase either by H2O2 under dark conditions or by OH radicals in the presence of light, using a photochemical reactor. Online and offline analytical techniques including SMPS, HR-AMS, H-TDMA, TD-API-AMS, were employed for physical and chemical characterization of the chamber SOA and nebulized filter extracts. After aqueous phase processing, the particles were significantly more hygroscopic, and HR-AMS data showed higher signal intensity at m/z 44 and a lower signal intensity at m/z 43, thus showing the impact of aqueous phase processing on SOA aging, in good agreement with a few previous studies. Additional offline measurement techniques (IC-MS, APCI-MS2 and HPLC-APCI-MS permitted the identification and quantification of sixteen individual chemical compounds before and after aqueous phase processing. Among these compounds, small organic acids (including formic, glyoxylic, glycolic, butyric, oxalic and 2,3-dihydroxymethacrylic acid (i.e. 2-methylglyceric acid were detected, and their concentrations significantly increased after aqueous phase processing. In particular, the aqueous phase formation of 2-methylglyceric acid and trihydroxy-3-methylbutanal was correlated with the consumption of 2,3-dihydroxy-2-methyl-propanal, and 2-methylbutane-1,2,3,4-tetrol, respectively, and an aqueous phase mechanism was proposed accordingly. Overall, the aging effect observed here was rather small compared to previous studies, and this limited effect could possibly be explained by the lower liquid phase OH

  7. Oxidation and photo-oxidation of water on TiO2 surface

    DEFF Research Database (Denmark)

    Valdes, A.; Qu, Z.W.; Kroes, G.J.


    The oxidation and photo-oxidation of water on the rutile TiO2(110) surface is investigated using density functional theory (DFT) calculations. We investigate the relative stability of different surface terminations of TiO2 interacting with H2O and analyze the overpotential needed for the electrol...


    Directory of Open Access Journals (Sweden)

    Ambar Rukmini


    Full Text Available The objective of this study was to investigate the keeping quality of commercial virgin coconut oil (VCO and toidentify the probable cause of its quality deterioration. Fourteen brands of commercial VCO and a fresh prepared VCO were used. Sensory evaluation on odor and taste was conducted. Free fatty acid (FFA, moisture, peroxide value (PV, tocopherol, carotenoid, chlorophyll-a, total phenolics content, and fatty acid compounds of VCO were analyzed. In order to observe the effect of photooxidation on the keeping quality, a fresh prepared VCO was packed in a transparent glass bottle and exposed to fluorescent light at 4,000 lux at room temperature for 5 h. PV of the samples were measured at 1 h interval. The results indicated that 10 out of 14 commercial VCO had PV of 1.0 meq/kg or higher and objectionable odor and taste were clearly detected by panelists. The PV of fresh prepared VCO was 0.14 meq/kg oil and only within3 h of light exposure (4,000 lux its PV reached 1.0 meq/kg oil. Naturally present antioxidants in the VCO were not effective for inhibiting photooxidation, while existing of 0.098 ppm chlorophyll-a effectively sensitized photooxidation reaction. This study confirmed that once the VCO undergoes brief photooxidation, subsequent protection using light barrier packaging material will not effective to inhibit quality deterioration during trading, display, or storage.

  9. Salt effect on sensitized photooxidations. A kinetic approch to environmental decomposition of marine contaminants

    Directory of Open Access Journals (Sweden)

    María I. Gutiérrez


    Full Text Available The salt effect on the kinetics of singlet molecular oxygen [O2(1Δg]-mediated photooxidations of sea water contaminants was investigated. Two families of photooxidizable compounds were employed in the study: anthracene derivatives and phenols. The presence of salt (NaCl in H2O and LiCl in MeCN, in both cases in the range 0-0.45 M produces changes in the photooxidation rate. For solvent-polarity-dependent reactions, this behavior can be predicted, by knowing the solvent-polarity dependence of the rate constant for chemical reaction of the substrates with O2(1Δ g in non-saline solutions (kr. For the cases of photooxidations possessing solvent-polarity-independent or scantily-dependent kr values, the photooxidation rates decrease as the salt content in the solution increases, mainly due to a predominance of the physical quenching pathway. In addition, the quantum yield for O2(1 Δg generation (ΦΔ was determined in a series of saline solutions, in the range of 0-0.45 M in water and MeCN solutions, in the presence of NaCl and LiCl respectively. The Δ values are independent, within the experimental error on the salt content.

  10. Cloud droplet activation of mixed organic-sulfate particles produced by the photooxidation of isoprene

    NARCIS (Netherlands)

    King, S.M.; Rosenoern, T.; Shilling, J.E.; Chen, Q.; Wang, Z.; Biskos, G.; McKinney, K.A.; Pöschl, U.; Martin, S.T.


    The cloud condensation nuclei (CCN) properties of ammonium sulfate particles mixed with organic material condensed during the hydroxyl-radical-initiated photooxidation of isoprene (C5H8) were investigated in the continuous-flow Harvard Environmental Chamber. CCN activation curves were measured for

  11. Increased prevalence of human papillomavirus in hairs plucked from patients with psoriasis treated with psoralen-UV-A. (United States)

    Wolf, Peter; Seidl, Hannes; Bäck, Barbara; Binder, Barbara; Höfler, Gerald; Quehenberger, Franz; Hoffmann, Christine; Kerl, Helmut; Stark, Sabine; Pfister, Herbert J; Fuchs, Pawel G


    Patients with psoriasis treated with psoralen-UV-A (PUVA) are at increased risk of skin cancer; however, the exact causes of this increased incidence are not well understood. It has been suggested that PUVA may increase expression of the tumorigenic agent human papillomavirus (HPV) in skin by directly stimulating virus replication, immune suppression, or both, thereby leading to skin cancer formation. To determine whether HPV DNA prevalence in the skin is increased after long-term PUVA treatment. Screening for the presence of HPV sequences in DNA isolated from plucked body hairs of patients with psoriasis with a history of PUVA exposure and a history of skin cancer (group A), PUVA exposure and no history of skin cancer (group B), and no PUVA exposure and no history of skin cancer (group C). University hospital. Hair samples were obtained from 81 patients with psoriasis (56 men and 25 women; mean age, 52 years), including 16 in group A (mean number of PUVA exposures, 702), 35 in group B (mean number of PUVA exposures, 282), and 30 in group C. DNA was isolated from the hair samples and analyzed by polymerase chain reaction with the use of 2 nested primer systems specific for epidermodysplasia verruciformis-associated or related and genital or mucosal virus types, respectively. The rate of HPV DNA positivity was significantly higher in groups A (73% [11/15]) and B (69% [24/35]) than in group C (36% [10/28]) (A + B vs C, P =.009; chi(2) test; age adjusted). Conclusion The prevalence of HPV in the skin (hair follicles) is increased in patients with psoriasis who have a history of PUVA exposure.

  12. TaSCL14, a novel wheat (Triticum aestivum L.) GRAS gene, regulates plant growth, photosynthesis, tolerance to photooxidative stress, and senescence. (United States)

    Chen, Kunmei; Li, Hongwei; Chen, Yaofeng; Zheng, Qi; Li, Bin; Li, Zhensheng


    Rates of photosynthesis, tolerance to photooxidative stress, and senescence are all important physiological factors that affect plant development and thus agricultural productivity. GRAS proteins play essential roles in plant growth and development as well as in plant responses to biotic and abiotic stresses. So far few GRAS genes in wheat (Triticum aestivum L.) have been characterized. A previous transcriptome analysis indicated that the expression of a GRAS gene (TaSCL14) was induced by high-light stress in Xiaoyan 54 (XY54), a common wheat cultivar with strong tolerance to high-light stress. In this study, TaSCL14 gene was isolated from XY54 and mapped on chromosome 4A. TaSCL14 was expressed in various wheat organs, with high levels in stems and roots. Our results confirmed that TaSCL14 expression was indeed responsive to high-light stress. Barley stripe mosaic virus (BSMV)-based virus-induced gene silencing (VIGS) of TaSCL14 in wheat was performed to help characterize its potential functions. Silencing of TaSCL14 resulted in inhibited plant growth, decreased photosynthetic capacity, and reduced tolerance to photooxidative stress. In addition, silencing of TaSCL14 in wheat promoted leaf senescence induced by darkness. These results suggest that TaSCL14 may act as a multifunctional regulator involved in plant growth, photosynthesis, tolerance to photooxidative stress, and senescence. Copyright © 2014 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.

  13. Effects and mechanisms of eugenol, isoeugenol, coniferylaldehyde and dihydroeugenol on the riboflavin-sensitized photooxidation of α-terpinene in methanol. (United States)

    Lee, Ju Yeon; Jung, Mun Yhung


    The effects of eugenol, isoeugenol, coniferylaldehyde, and dihydroeugenol on the riboflavin-sensitized photooxidation of α-terpinene in methanol were studied. Riboflavin greatly accelerated α-terpinene oxidation in methanol during light illumination, resulting in two major oxidation products (p-cymene and ascaridole). The results clearly showed the involvement of Type I and II mechanisms. All the eugenols exerted strong protective activity on riboflavin sensitized photooxidation of α-terpinene. Dihydroeugenol showed the highest protective activity, followed by isoeugenol, coniferylaldehyde, and eugenol, in a decreasing order. Dihydroeugenol greatly inhibited the production of ascaridole, but showed relatively low inhibitory activity on the formation of p-cymene. The protective activity of dihydroeugenol was higher than those of BHA, BHT and sodium azide. Sodium azide, a specific singlet oxygen quencher, showed strong inhibitory activity on the formation of ascaridole, but very low inhibitory activity on the formation of p-cymene, verifying the feasibility of mechanism study with the present model system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Mutant pso8-1 of Saccharomyces cerevisiae, sensitive to photoactivated psoralens, UV radiation, and chemical mutagens, contains a rad6 missense mutant allele. (United States)

    Rolla, H; Grey, M; Schmidt, C L; Niegemann, E; Brendel, M; Henriques, J A P


    A novel mutant isolate of Saccharomyces cerevisiae, sensitive to photoactivated mono- and bi-functional psoralens, to UV at 254 nm (UVC), and to nitrosoguanidine, was found to complement the photoactivated psoralen-sensitivity phenotype conferred by the pso1- pso7 mutations and was therefore named pso8-1. A constructed pso8-1 rad4-4 double mutant was super-sensitive to UVC, thus indicating a synergistic interaction of the two mutant alleles. Molecular cloning via complementation of the pso8 mutant's sensitivity phenotype and genetic studies revealed that pso8 is allelic to RAD6. While a pso8-1 mutant had low mutagen-induced mutability, homoallelic diploids showed nearly wild-type sporulation. Sequence analysis of the mutant allele showed pso8-1 to contain a novel, hitherto undescribed T-->C transition in nucleotide position 191, leading to a substitution by leucine of a highly conserved proline at position 64, Rad6-[P64L], which may have severe consequences for the tertiary structure (and hence binding to Rad18p) of the mutant protein.

  15. Molecular characterization of urban organic aerosol in tropical India: contributions of primary emissions and secondary photooxidation

    Directory of Open Access Journals (Sweden)

    P. Q. Fu


    Full Text Available Organic molecular composition of PM10 samples, collected at Chennai in tropical India, was studied using capillary gas chromatography/mass spectrometry. Fourteen organic compound classes were detected in the aerosols, including aliphatic lipids, sugar compounds, lignin products, terpenoid biomarkers, sterols, aromatic acids, hydroxy-/polyacids, phthalate esters, hopanes, Polycyclic Aromatic Hydrocarbons (PAHs, and photooxidation products from biogenic Volatile Organic Compounds (VOCs. At daytime, phthalate esters were found to be the most abundant compound class; however, at nighttime, fatty acids were the dominant one. Di-(2-ethylhexyl phthalate, C16 fatty acid, and levoglucosan were identified as the most abundant single compounds. The nighttime maxima of most organics in the aerosols indicate a land/sea breeze effect in tropical India, although some other factors such as local emissions and long-range transport may also influence the composition of organic aerosols. However, biogenic VOC oxidation products (e.g., 2-methyltetrols, pinic acid, 3-hydroxyglutaric acid and β-caryophyllinic acid showed diurnal patterns with daytime maxima. Interestingly, terephthalic acid was maximized at nighttime, which is different from those of phthalic and isophthalic acids. A positive relation was found between 1,3,5-triphenylbenzene (a tracer for plastic burning and terephthalic acid, suggesting that the field burning of municipal solid wastes including plastics is a significant source of terephthalic acid. Organic compounds were further categorized into several groups to clarify their sources. Fossil fuel combustion (24–43% was recognized as the most significant source for the total identified compounds, followed by plastic emission (16–33%, secondary oxidation (8.6–23%, and microbial/marine sources (7.2–17%. In contrast, the contributions of terrestrial plant waxes (5.9–11% and biomass burning (4.2–6.4% were relatively

  16. Radiation stimulation during the early stationary growth phase in Synechococcus lividus and its correlation with photooxidative stress occurring before the stationary phase

    Energy Technology Data Exchange (ETDEWEB)

    Conter, A.; Dupouy, D.; Vincent, C.; Planel, H.


    The effects of chronic gamma radiation at dose rates ranging from 0.058 mGy d-1 on growth rate calculated during the early stationary phase were studied. A stimulatory effect occurred for all doses and for all phases of the cells selected for use in the inoculation of the medium. During the same period, the rate of nucleic acid synthesis was increased in irradiated cultures compared to control cultures. The stimulating effect always occurred in cultures irradiated from the inoculation to the eighteenth day only. This result led us to conclude that the stimulation mechanism depended upon the events occurring at the end of the exponential phase in the deceleration period. Studies on cell metabolism showed that cells presented features of photooxidative stress in this period. Increases in superoxide dismutase, glutathione reductase and glucose-6-phosphate dehydrogenase were observed in irradiated cultures. It was assumed that irradiation at very low doses could help cells to better defend against photooxidative stress by increasing oxidants that activate the glucose metabolism and C5-sugars production and nucleic acid synthesis.

  17. Evaluation of effects of photooxidized Vespa orientalis venom on memory and learning in rats


    Mukund, H; SP Gawade


    Wasp venom is mixture of complex proteins that have several physical and pharmacological properties. The photochemical detoxification of Vespa orientalis venom is expected to generate photooxidized venom sac extract (PVSE). Antigenically active PVSE is obtained by exposing the venom sac extract (VSE) of Vespa orientalis to ultraviolet radiation in the presence of methylene blue. The aim of the present work was to evaluate the effect of PVSE on learning and memory of rats. Detoxification of PV...

  18. Narrow-band ultraviolet B phototherapy versus broad-band ultraviolet B or psoralen-ultraviolet A photochemotherapy for psoriasis. (United States)

    Chen, Xiaomei; Yang, Ming; Cheng, Yan; Liu, Guan J; Zhang, Min


    The most commonly used types of phototherapy for treating psoriasis are narrow-band ultraviolet B (NB-UVB); broad-band ultraviolet B (BB-UVB), which includes selective (delivering radiation with a wavelength range of 305 to 325 nm) and conventional BB-UVB (280 to 320 nm); and psoralen ultraviolet A photochemotherapy (oral or bath PUVA). There is substantial controversy regarding their efficacy when compared with each other. To assess the effects of narrow-band ultraviolet B phototherapy versus broad-band ultraviolet B or psoralen ultraviolet A photochemotherapy for psoriasis. We searched the following databases up to August 2013: the Cochrane Skin Group Specialised Register, CENTRAL in The Cochrane Library (2013, Issue 7), MEDLINE (from 1946), and EMBASE (from 1974). We searched the following databases up to November 2012: CNKI (from 1974) and CBM (from 1978). We also searched trials registers and the OpenGrey database. We included all randomised controlled trials (RCTs) that compared NB-UVB phototherapy with BB-UVB or PUVA for treating psoriasis, which included chronic plaque psoriasis (CPP), guttate psoriasis (GP), and palmoplantar psoriasis (PPP). Two review authors independently conducted the study selection, 'Risk of bias' assessment, and data extraction. We included 13 RCTs, with a total of 662 participants. We report the results of intention-to-treat analyses (ITT) here. Our primary outcomes of interest were as follows: Participant-rated global improvement, Percentage of participants reaching Psoriasis Area and Severity Index (PASI) 75 (which meant equal to or more than 75% reduction in PASI score), Withdrawal due to side-effects, and Clearance rate.In one RCT of NB-UVB compared with oral PUVA in participants with CPP, the difference in PASI 75 was not statistically significant (risk ratio (RR) 0.91, 95% confidence interval (CI) 0.63 to 1.32; N = 51; low quality). In three other RCTs of CPP, the clearance rates were inconsistent because in one, there was no

  19. Visible light photooxidative performance of a high-nuclearity molecular bismuth vanadium oxide cluster

    Directory of Open Access Journals (Sweden)

    Johannes Tucher


    Full Text Available The visible light photooxidative performance of a new high-nuclearity molecular bismuth vanadium oxide cluster, H3[{Bi(dmso3}4V13O40], is reported. Photocatalytic activity studies show faster reaction kinetics under anaerobic conditions, suggesting an oxygen-dependent quenching of the photoexcited cluster species. Further mechanistic analysis shows that the reaction proceeds via the intermediate formation of hydroxyl radicals which act as oxidant. Trapping experiments using ethanol as a hydroxyl radical scavenger show significantly decreased photocatalytic substrate oxidation in the presence of EtOH. Photocatalytic performance analyses using monochromatic visible light irradiation show that the quantum efficiency Φ for indigo photooxidation is strongly dependent on the irradiation wavelength, with higher quantum efficiencies being observed at shorter wavelengths (Φ395nm ca. 15%. Recycling tests show that the compound can be employed as homogeneous photooxidation catalyst multiple times without loss of catalytic activity. High turnover numbers (TON ca. 1200 and turnover frequencies up to TOF ca. 3.44 min−1 are observed, illustrating the practical applicability of the cluster species.

  20. Photo-oxidative degradation of TiO{sub 2}/polypropylene films

    Energy Technology Data Exchange (ETDEWEB)

    García-Montelongo, X.L. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); Martínez-de la Cruz, A., E-mail: [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); Vázquez-Rodríguez, S. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); Torres-Martínez, Leticia M. [Facultad de Ingeniería Civil, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico)


    Graphical abstract: - Highlights: • Photo-oxidative degradation of polypropylene is accelerated by TiO{sub 2} incorporation. • Weight loss, FTIR, SEM and GPC shown high degree of degradation of polypropylene. • A mechanism of the photo-degradation of polypropylene by TiO{sub 2} is proposed. - Abstract: Photo-oxidative degradation of polypropylene films with TiO{sub 2} nanoparticles incorporated was studied in a chamber of weathering with Xenon lamps as irradiation source. TiO{sub 2} powder with crystalline structure of anatase was synthesized by thermal treatments at 400 and 500 °C starting from a precursor material obtained by sol–gel method. Composites of TiO{sub 2}/polypropylene were prepared with 0.1, 0.5 and 1.0 wt% of TiO{sub 2}. The mixture of components was performed using a twin screw extruder, the resulting material was pelletized by mechanical fragmenting and then hot-pressed in order to form polypropylene films with TiO{sub 2} dispersed homogeneously. Photo-oxidative degradation process was followed by visual inspection, weight loss of films, scanning electron microscopy (SEM), infrared spectroscopy with Fourier transformed (FTIR), and gel permeation chromatography (GPC)

  1. UV/Fenton photo-oxidation of Drimarene Dark Red (DDR) containing textile-dye wastewater (United States)

    Hudaya, T.; Anthonios, J.; Septianto, E.


    Textile dye wastewater contains organic pollutants which are non-biodegradable, characterized by low BOD/COD ratio of typically Fenton) offers not only relatively low cost but also quite effective (in terms of color removal and reaction time) treatment. This particular research aimed to optimize the conditions of UV/Fenton photo-oxidation process for Drimarene Dark Red containing textile- dye wastewater. The two main operating conditions to be optimized were the initial concentration of H2O2 ranged between 0.022-0.078 %-w and the mol ratio of Fe2+: H2O2 was varied from 1: 13 up to 1: 45, using the Central Composite Design experimental matrix. The photo-oxidation was carried out at the optimum pH of 3 from some previous experiments. The best processing conditions of the photo-oxidation of Drimarene Dark Red (DDR) were found at the initial concentration of H2O2 at 0.050%-w and the mole ratio Fe2+: H2O2 of 1: 22. Under these conditions, the measured 2nd order pseudo-rate constantwas 0.021 M-1.min-1. The DDR color removal of 90% was surprisingly achievable within only 10 minutes reaction time.

  2. Secondary organic aerosol from atmospheric photooxidation of indole

    Directory of Open Access Journals (Sweden)

    J. Montoya-Aguilera


    Full Text Available Indole is a heterocyclic compound emitted by various plant species under stressed conditions or during flowering events. The formation, optical properties, and chemical composition of secondary organic aerosol (SOA formed by low-NOx photooxidation of indole were investigated. The SOA yield (1. 3 ± 0. 3 was estimated from measuring the particle mass concentration with a scanning mobility particle sizer (SMPS and correcting it for wall loss effects. The high value of the SOA mass yield suggests that most oxidized indole products eventually end up in the particle phase. The SOA particles were collected on filters and analysed offline with UV–vis spectrophotometry to measure the mass absorption coefficient (MAC of the bulk sample. The samples were visibly brown and had MAC values of  ∼ 2 m2 g−1 at λ = 300 nm and  ∼ 0. 5 m2 g−1 at λ = 400 nm, comparable to strongly absorbing brown carbon emitted from biomass burning. The chemical composition of SOA was examined with several mass spectrometry methods. Direct analysis in real-time mass spectrometry (DART-MS and nanospray desorption electrospray high-resolution mass spectrometry (nano-DESI-HRMS were both used to provide information about the overall distribution of SOA compounds. High-performance liquid chromatography, coupled to photodiode array spectrophotometry and high-resolution mass spectrometry (HPLC-PDA-HRMS, was used to identify chromophoric compounds that are responsible for the brown colour of SOA. Indole derivatives, such as tryptanthrin, indirubin, indigo dye, and indoxyl red, were found to contribute significantly to the visible absorption spectrum of indole SOA. The potential effect of indole SOA on air quality was explored with an airshed model, which found elevated concentrations of indole SOA during the afternoon hours contributing considerably to the total organic aerosol under selected scenarios. Because of its high MAC values

  3. SOA formation from the photooxidation of α-pinene: systematic exploration of the simulation of chamber data

    Directory of Open Access Journals (Sweden)

    R. C. McVay


    Full Text Available Chemical mechanisms play an important role in simulating the atmospheric chemistry of volatile organic compound oxidation. Comparison of mechanism simulations with laboratory chamber data tests our level of understanding of the prevailing chemistry as well as the dynamic processes occurring in the chamber itself. α-Pinene photooxidation is a well-studied system experimentally, for which detailed chemical mechanisms have been formulated. Here, we present the results of simulating low-NO α-pinene photooxidation experiments conducted in the Caltech chamber with the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A under varying concentrations of seed particles and OH levels. Unexpectedly, experiments conducted at low and high OH levels yield the same secondary organic aerosol (SOA growth, whereas GECKO-A predicts greater SOA growth under high OH levels. SOA formation in the chamber is a result of a competition among the rates of gas-phase oxidation to low-volatility products, wall deposition of these products, and condensation into the aerosol phase. Various processes – such as photolysis of condensed-phase products, particle-phase dimerization, and peroxy radical autoxidation – are explored to rationalize the observations. In order to explain the observed similar SOA growth at different OH levels, we conclude that vapor wall loss in the Caltech chamber is likely of order 10−5 s−1, consistent with previous experimental measurements in that chamber. We find that GECKO-A tends to overpredict the contribution to SOA of later-generation oxidation products under high-OH conditions. Moreover, we propose that autoxidation may alternatively resolve some or all of the measurement–model discrepancy, but this hypothesis cannot be confirmed until more explicit mechanisms are established for α-pinene autoxidation. The key role of the interplay among oxidation rate, product volatility, and vapor–wall deposition

  4. Photo-oxidation of 2-Mcthyl-1-phenylcyclohexcne

    African Journals Online (AJOL)

    energy-demanding flip of conformation. Another factor that could contribute to the exclusive abstraction of HR is its statistical advantage over Hb , the protons being in the ratio 3:] respectively. However, this would also have resulted in a product excess of (2) over (3), instead of the lzl ratio observed for the products. Thus the ...

  5. Effects on surface atmospheric photo-oxidants over Greece during the total solar eclipse event of 29 March 2006

    Directory of Open Access Journals (Sweden)

    P. Zanis


    Full Text Available This study investigates the effects of the total solar eclipse of 29 March 2006 on surface air-quality levels over Greece based on observations at a number of sites in conjunction with chemical box modelling and 3-D air-quality modelling. Emphasis is given on surface ozone and other photooxidants at four Greek sites Kastelorizo, Finokalia (Crete, Pallini (Athens and Thessaloniki, which are located at gradually increasing distances from the path of the eclipse totality and are characterized by different air pollution levels. The eclipse offered the opportunity to test our understanding of air pollution build-up and the response of the gas-phase chemistry of photo-oxidants during a photolytical perturbation using both a photochemical box model and a regional air-quality offline model based on the modeling system WRF/CAMx. At the relatively unpolluted sites of Kastelorizo and Finokalia no clear signal of the solar eclipse on surface O3, NO2 and NO concentrations can be deduced from the observations while there is no correlation of observed O3, NO2 and NO with observed global radiation. The box and regional model simulations for the two relatively unpolluted sites indicate that the calculated changes in net ozone production rates between eclipse and non eclipse conditions are rather small compared to the observed short-term ozone variability. Furthermore the simulated ozone lifetime is in the range of a few days at these sites and hence the solar eclipse effects on ozone can be easily masked by local and regional transport. At the polluted sites of Thessaloniki and Pallini, the solar eclipse effects on O3, NO2 and NO concentrations are revealed from both the measurements and modeling with the net effect being a decrease in O3 and NO and an increase in NO2 as NO2 formed from the reaction of O3 with NO while at the same time NO2 is

  6. Psoriasis, Psoralen and Sunlight

    Directory of Open Access Journals (Sweden)

    R.P.C Naik


    Full Text Available Topical or oral administration of photoactive furocumarins followed by exposure to ultra violet light from artificial sources has been shown previously to clear psoriatic lesions. Sunlight has been chosen as the source of UVL m two separate paired comparison studies using topical and, oral 4,5, 8 trimethylpsoralen. Two out of 21 on topical therapy and none out of 6 patients on oral paired-comparison study showed faster clearance of the drug treated lesions compared to control sites.

  7. Protein Characterization of Javan Cobra (Naja sputatrix) Venom Following Sun Exposure and Photo-Oxidation Treatment (United States)

    Sulistiyani; Biki, R. S.; Andrianto, D.


    Snake venom has always been known for its toxicity that can cause fatality, however, it is also one of the important biological resources to be used for disease treatment. In Indonesia, snake venom previously expose under the sun has been used for alternative treatment of some diseases such as dengue fever, atherosclerosis, cancer, and diabetes. There has been very little scientific evidence on the use of snake venom of Indonesia origin as well as its protein characteristic. Thus, the objective of this research is to characterize the protein content and the specific activity of the venom of Javan Cobra (N.sputatrix) when treated with sun exposure in comparison with photo-oxidation by ultraviolet. Qualitative analysis of protein contents was determined using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE). The L-amino acid oxidase activity (LAAO) and the phospholipase A2 (PLA2) activities were determined using spectrophotometry. The venom’s protein was separated into 5 main protein bands with molecular weight ranging from 14 to 108 kDa. A time course study showed that the venom lost 91% of its LAAO activity and 96% of PLA2 activity after 6 hours of sun exposure. UV photo-oxidation carried out for 3 hours decreased 91% of LAAO activity, and almost diminished all of PLA2 activity (99.8%). These findings suggest that the exposure of N. sputatrix venom under the sun and UV photo-oxidation decreased its toxicity as shown by the significant reduction of the enzymes activity, but did not affect the protein’s integrity. Therefore, these approaches produced N.sputatrix venom with less toxicity but still withheld other characters of intact proteins.

  8. Metabolism in orange fruits is driven by photooxidative stress in the leaves. (United States)

    Poiroux-Gonord, Florine; Santini, Jérémie; Fanciullino, Anne-Laure; Lopez-Lauri, Félicie; Giannettini, Jean; Sallanon, Huguette; Berti, Liliane; Urban, Laurent


    In plants, stress signals propagate to trigger distant responses and thus stress acclimation in non-exposed organs. We tested here the hypothesis that leaves submitted to photooxidative stress may influence the metabolism of nearby fruits and thus quality criteria. Leaves of orange trees (Citrus sinensis (L.) Osbeck cv. 'Navelate') were acclimated to shade for 1 week and then submitted to full (FL) and medium light (ML) conditions. As expected, photoinhibition was detected in leaves of both FL and ML treatments as revealed by stress indicators (Fv /Fm , Performance Index) for at least 99 h after treatments. In the fruits near the stressed leaves, we then determined the activities of enzymes related to oxidative stress, superoxide dismutase, catalase and the enzymes of the ascorbate (AA)/glutathione cycle, as well as the contents in sugars, organic acids and carotenoids. Ascorbate peroxidase and monodehydroascorbate reductase activities in the pulp of fruits were dramatically higher in both treatments when compared to the control. AA and total sugars were not affected by the photooxidative stress. However, the FL treatment resulted in a 16% increase in total organic acids, with succinic acid being the major contributor, a shift towards less glucose + fructose and more sucrose, and a 15% increase in total carotenoids, with cis-violaxanthin being the major contributor. Our observations strongly suggest the existence of a signal generated in leaves in consequence of photooxidative stress, transmitted to nearby fruits. Exploiting such a signal by agronomic means promises exciting perspectives in managing quality criteria in fruits accumulating carotenoids. © 2013 Scandinavian Plant Physiology Society.

  9. Type and distribution of chemical groups from controlled photo-oxidation of gyroid nanoporous 1,2-polybutadiene

    DEFF Research Database (Denmark)

    Sagar, Kaushal Shashikant; Christiansen, Mads Brøkner; Ndoni, Sokol


    Photo-oxidation of nanoporous polymers is little studied. The high UV penetration depth and high surface concentration in these materials give unprecedented possibilities both in fundamental work on surface photochemistry and in nanotechnological applications related for example to patterned hydr......-scale polymer–air interface, and as a function of irradiation depth in the sample, is studied by gravimetry, titrimetry, ATR-FTIR and energy dispersive X-ray spectroscopy in scanning electron microscopy....... of hydrophilic chemical groups, carboxyl and hydroxyls, mainly onto the large air–polymer interface. The nature and abundance of the chemical groups induced by photo-oxidation is identified by solid-state 13C-NMR and FTIR spectroscopy. The distribution of photo-oxidation groups, both relative to the nanometre...

  10. Photooxidation processes for an azo dye in aqueous media: modeling of degradation kinetic and ecological parameters evaluation. (United States)

    Kusic, Hrvoje; Juretic, Daria; Koprivanac, Natalija; Marin, Vedrana; Božić, Ana Lončarić


    Three photooxidation processes, UV/H(2)O(2), UV/S(2)O(8)(2-) and UV/O(3) were applied to the treatment of model wastewater containing non-biodegradable organic pollutant, azo dye Acid Orange 7 (AO7). Dye degradation was monitored using UV/VIS and total organic carbon (TOC) analysis, determining decolorization, the degradation/formation of naphthalene and benzene structured AO7 by-products, and the mineralization of model wastewater. The water quality during the treatment was evaluated on the bases of ecological parameters: chemical (COD) and biochemical (BOD(5)) oxygen demand and toxicity on Vibrio fischeri determining the EC(50) value. The main goals of the study were to develop an appropriate mathematic model (MM) predicting the behavior of the systems under investigation, and to evaluate the toxicity and biodegradability of the model wastewater during treatments. MM developed showed a high accuracy in predicting the degradation of AO7 when considering the following observed parameters: decolorization, formation/degradation of by-products and mineralization. Good agreement of the data predicted and the empirically obtained was confirmed by calculated standard deviations. The biodegradability of model wastewater was significantly improved by three processes after mineralizing a half of the initially present organic content. The toxicity AO7 model wastewater was decreased as well. The differences in monitored ecological parameters during the treatment indicated the formation of different by-products of dye degradation regarding the oxidant type applied. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Photooxidants in the marine Arctic troposphere in summer (United States)

    Weller, R.; Schrems, O.


    The air chemistry investigations, performed on R/V Polarstern during the expedition ARK X/1 in July/August 1994, comprised a mapping of the vertical ozone distribution by ozone soundings and the surface mixing ratios of H2O2 and NO above the East Greenland Sea between 70°N and 80°N. The observed H2O2 mixing ratios varied from about 100 parts per trillion by volume (pptv) up to around 1000 pptv. Surface ozone concentrations can be correlated with the source region of the advected air masses. Ozone mixing ratios from around 33 parts per billion by volume (ppbv) up to 60 ppbv have been observed in air parcels emanating from industrialized regions. In contrast, pristine Arctic air masses showed low ozone mixing ratios of about 23 ppbv. The tropospheric part of the vertical ozone profiles occasionally exhibited significant maxima above the planetary boundary layer. Apart from cases where intrusions of stratospheric ozone were obvious, photochemical ozone formation along trajectories originating from polluted regions was most probably the reason for layers with enhanced ozone concentrations. The measured surface NO mixing ratios were extremely low, typically between 3 and 8 pptv. Thus local photochemical surface ozone production could be largely ruled out. In conclusion it can be stated that in summer, intrusion of ozone rich stratospheric air and advection of polluted air masses from lower latitudes appeared to be the dominant ozone sources of the marine Arctic troposphere.

  12. Evaluation of effects of photooxidized Vespa orientalis venom on memory and learning in rats

    Directory of Open Access Journals (Sweden)

    H Mukund


    Full Text Available Wasp venom is mixture of complex proteins that have several physical and pharmacological properties. The photochemical detoxification of Vespa orientalis venom is expected to generate photooxidized venom sac extract (PVSE. Antigenically active PVSE is obtained by exposing the venom sac extract (VSE of Vespa orientalis to ultraviolet radiation in the presence of methylene blue. The aim of the present work was to evaluate the effect of PVSE on learning and memory of rats. Detoxification of PVSE was evident since treated mice had longer survival time than the group of mice treated with VSE. Photooxidized VSE of V. orientalis revealed enhancement on learning and memory by shortening the time to reach food (TRF in T-maze. In a 28-day study with rats, we observed that PVSE significantly decreased transfer latency (TL in elevated plus maze (EPM, significantly increased step down latency (SDL, diminished step down errors (SDE and time spent in shock zone (TSS in step down avoidance test. Thus, we concluded that although there is a possibility of employing PVSE in the treatment of Alzheimer, dementia or neurodegenerative illness as a non-herbal and non-synthetic alternative for patients who do not respond to available therapy, further investigation is still required.

  13. Photooxidation of cyclohexene in the presence of SO2: SOA yield and chemical composition (United States)

    Liu, Shijie; Jia, Long; Xu, Yongfu; Tsona, Narcisse T.; Ge, Shuangshuang; Du, Lin


    Secondary organic aerosol (SOA) formation from a cyclohexene / NOx system with various SO2 concentrations under UV light was investigated to study the effects of cyclic alkenes on the atmospheric environment in polluted urban areas. A clear decrease at first and then an increase in the SOA yield was found with increasing SO2 concentrations. The lowest SOA yield was obtained when the initial SO2 concentration was in the range of 30-40 ppb, while higher SOA yield compared to that without SO2 could not be obtained until the initial SO2 concentration was higher than 85 ppb. The decreasing SOA yield might be due to the fact that the promoting effect of acid-catalysed reactions on SOA formation was less important than the inhibiting effect of decreasing OH concentration at low initial SO2 concentrations, caused by the competition reactions of OH with SO2 and cyclohexene. The competitive reaction was an important factor for SOA yield and it should not be neglected in photooxidation reactions. The composition of organic compounds in SOA was measured using several complementary techniques including Fourier transform infrared (FTIR) spectroscopy, ion chromatography (IC), and Exactive Plus Orbitrap mass spectrometer equipped with electrospray interface (ESI). We present new evidence that organosulfates were produced from the photooxidation of cyclohexene in the presence of SO2.

  14. Superhydrophobic Polyimide via Ultraviolet Photooxidation: The Evolution of Surface Morphology and Hydrophobicity under Different Ultraviolet Intensities

    Directory of Open Access Journals (Sweden)

    Hongyu Gu


    Full Text Available Ultraviolet (UV photooxidation has recently been developed to fabricate superhydrophobic polyimide (PI films in combination with fluoroalkylsilane modification. However, it remains unclear whether the surface morphology and hydrophobicity are sensitive to technical parameters such as UV intensity and radiation environment. Herein, we focus on the effects of UV intensity on PI surface structure and wettability to gain comprehensive understanding and more effective control of this technology. Scanning electron microscopy (SEM and atomic force microscopy (AFM results showed that UV intensity governed the evolutionary pattern of surface morphology: lower UV intensity (5 mW/cm2 facilitated in-plane expansion of dendritic protrusions while stronger UV (10 and 15 mW/cm2 encouraged localized growth of protrusions in a piling-up manner. Surface roughness and hydrophobicity maximized at the intensity of 10 mW/cm2, as a consequence of the slowed horizontal expansion and preferred vertical growth of the protrusions when UV intensity increased. Based on these results, the mechanism that surface micro/nanostructures developed in distinct ways when exposed to different UV intensities was proposed. Though superhydrophobicity (water contact angle larger than 150° can be achieved at UV intensity not less than 10 mW/cm2, higher intensity decreased the effectiveness. Therefore, the UV photooxidation under 10 mW/cm2 for 72 h is recommended to fabricate superhydrophobic PI films.

  15. Superhydrophobic polyimide films with high thermal endurance via UV photo-oxidation

    Directory of Open Access Journals (Sweden)

    L. X. Song


    Full Text Available UV photo-oxidation was first applied to fabricate superhydrophobic polyimide (PI films in combination with fluoroalkylsilane (FAS modification. During prolonged UV irradiation, commercial flat PI films evolved to form unique micro/nanostructures. Meanwhile, the root mean square (RMS surface roughness increased from 1.74 to 53.70 nm, leading to a gradual increase of WCA from 105.1 to 159.2° after FAS treatment. After 72 h of UV radiation exposure, the micro/nano-structured and FAS-modified PI films exhibited superhydrophobicity with water contact angle (WCA larger than 150° and sliding angle (SA less than 5°. The superhydrophobicity remained even after annealing at 350°C, which enabled stable utilization under elevated temperature. Stable micro/nanostructures and chemical bonding of FAS were found to contribute to the high thermal endurance. Moreover, the formation mechanism of the superhydrophobic PI films was investigated. The proposed UV photo-oxidation method provides a new route for the industrial fabrication of thermally stable superhydrophobic PI films.

  16. On the use of UV photo-oxidation for the determination of total nitrogen in rainwater and water-extracted atmospheric aerosol (United States)

    Mace, Kimberly A.; Duce, Robert A.

    Three methods are currently in use for the determination of total N within rainwater and water-extracted aerosols—UV photo-oxidation, persulfate digestion, and high-temperature combustion. Among these methods, UV photo-oxidation has received scrutiny for its reported inability to digest "refractory" organic N compounds. In this manuscript we utilized inorganic and organic nitrogen standards to carefully assess the ability of a specific UV digestor, the Metrohm 705 UV digestor, to correctly digest organic N within dilute solutions (such as rainwater and atmospheric aerosol). We also discuss the negative aspects of the three methods listed above, comment on the photochemical reactions and chemical products produced by exposure to UV light, and make suggestions concerning the proper use of UV digestion technique when determining total N. Our tests indicate that at a digestion time of 2 h and a temperature of 85°C the system is satisfactory for determining the total amount of organic N within dilute solutions. The upper concentration limit using this UV system was found to be 50 μM N of organic N. Diluted samples were found to carry a larger burden of analytical error due to the combined effects of UV blanks (that can range from 0.1-0.6 μM N) and the uncertainty associated with the chromatographic ion analysis (for nitrate, nitrite, and ammonium). This error can often lead to negative values when reporting organic N. We suggest that negative values for organic N be included within the mean and standard deviation of organic N measurements rather than excluding them by rounding negative values to zero. Only by including all analytical error within measurements will true concentrations of organic N within rainwater and atmospheric aerosols and its relevance to total N budgets be known.

  17. In Situ ATR-FTIR Study on the Selective Photo-oxidation of Cyclohexane over Anatase TiO2

    NARCIS (Netherlands)

    Almeida, A.; Moulijn, J.A.; Mul, Guido


    Anatase-catalyzed photo-oxidation of cyclohexane was analyzed by in situ ATR-FTIR spectroscopy. A set of seven UV-LEDs (375 nm), with a photon flux of 9 × 10-9 Einstein·cm-2·s-1 (at the catalyst surface) was used to initiate the photoreaction. Surface-adsorbed cyclohexanone and water are the primary

  18. Photophysical Behavior of Modified Xanthenic Dyes Embedded into Silsesquioxane Hybrid Films: Application in Photooxidation of Organic Molecules

    Directory of Open Access Journals (Sweden)

    Carolina V. Waiman


    Full Text Available Polymeric materials based on a bridged silsesquioxane with pendant dodecyl chains were synthesized and modified with different xanthenic dyes with the aim of developing a material with potential application in photooxidation of organic compounds. The employed dyes constitute a family of novel xanthenic chromophores with outstanding properties as singlet oxygen photosensitizers. The hybrid matrix was chosen for its enhanced properties such as flexibility and chemical resistance. The employed dyes were easily incorporated into the hybrid polymer obtaining homogeneous, transparent, and low-refractive-index materials. The polymeric films were characterized using UV-Vis absorption, fluorescence, and laser flash photolysis techniques. The ability of these materials to produce singlet oxygen was tested following the photooxidation of 9,10-dimethylanthracene which is a well-known chemical trap for singlet oxygen. High photooxidation efficiencies were observed for these materials, which present the advantage of being easily removed/collected from the solution where photooxidation takes place. While photobleaching of the incorporated dyes is commonly observed in the solution, it takes place very slowly when dyes are embedded in the hybrid matrix. These properties bode well for the potential use of these materials in novel wastewater purification strategies.

  19. Protein hydroperoxides and carbonyl groups generated by porphyrin-induced photo-oxidation of bovine serum albumin

    DEFF Research Database (Denmark)

    Silvester, J A; Timmins, G S; Davies, Michael Jonathan


    Porphyrin-sensitized photo-oxidation of bovine serum albumin results in oxidation at specific sites to produce protein radical species: at the Cys-34 residue (to give a thiyl radical) and at one or both tryptophan residues (Trp-134 and Trp-214) to give tertiary carbon-centered radicals and cause...

  20. Natural montmorillonite induced photooxidation of As(III) in aqueous suspensions: roles and sources of hydroxyl and hydroperoxyl/superoxide radicals. (United States)

    Wang, Yajie; Xu, Jing; Li, Jinjun; Wu, Feng


    Photooxidation of arsenite(As(III)) in a suspension of natural montmorillonite under the irradiation of metal halide lamp (λ ≥ 313 nm)has been investigated. The results showed that the natural montmorillonite induced the photooxidation of As(III) by generating hydroxyl radicals (HO·) and hydroperoxyl/superoxide radicals (HO₂·/O₂⁻·). HO· which was responsible for the As(III) photooxidation. Approximately 38% of HO· was generated by the photolysis of ferric ions, and the formation of the remaining 62% was strongly dependent on the HO₂·/O₂⁻·. The presence of free ironions (Fe(2+) and Fe(3+)), made significant contributions to the photogeneration of these reactive oxygen species (ROS). The photooxidation of As(III) in natural montmorillonite suspensions was greatly influenced by the pH values. The photooxidation of As(III) by natural montmorillonite followed the Langmuir-Hinshelwood equation. In addition, the photooxidation of As(III) could be enhanced by the addition of humic acid. This work demonstrates that photooxidation may be an important environmental process for the oxidation of As(III) and may be a way to remove As(III) from acidic surface water containing iron-bearing clay minerals. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Product desorption limitations in selective photocatalytic oxidation

    NARCIS (Netherlands)

    Renckens, T.J.A.; Almeida, A.R.; Almeida, A.R.; Damen, M.R.; Kreutzer, M.T.; Mul, Guido


    The rate of photocatalytic processes can be significantly improved if strongly bound products rapidly desorb to free up active sites. This paper deals with the rate of desorption of cyclohexanone, the product of the liquid-phase photo-oxidation of cyclohexane. Dynamic step-response and

  2. Molecular analysis by electron microscopy of the removal of psoralen-photoinduced DNA cross-links in normal and Fanconi's anemia fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Rousset, S.; Nocentini, S.; Revet, B.; Moustacchi, E. (Institut Curie, Biologie, Paris (France))


    The induction and fate of psoralen-photoinduced DNA interstrand cross-links in the genome of Fanconi's anemia (FA) fibroblasts of complementation groups A and B, and of normal human fibroblasts, were investigated by quantitative analysis of totally denatured DNA fragments visualized by electron microscopy. 8-Methoxypsoralen (5 x 10(-5) M) interstrand cross-links were induced as a function of the near ultraviolet light dose. With time of postexposure incubation, a fraction of interstrand cross-links disappeared in all cell lines. However, 24 h after treatment, this removal was significantly lower in the two FA group A cell lines examined (34-39%) than in the FA group B and normal cell lines (43-53 and 47-57%, respectively). These data indicate that FA cells are at least able to recognize and incise interstrand cross-links, as normal cells do, although group A cells seem somewhat hampered in this process. This is in accord with data obtained on the same cell lines using another biochemical assay. Since the fate of cross-links in FA constituted a controversial matter, it is important to stress that two different methodologies applied to genetically well defined cell lines led to the same conclusions.

  3. Inactivation of viruses in platelet suspensions that retain their in vitro characteristics: Comparison of psoralen-ultraviolet A and merocyanine 540-visible light methods

    Energy Technology Data Exchange (ETDEWEB)

    Dodd, R.Y.; Moroff, G.; Wagner, S.; Dabay, M.H.; Dorfman, E.; George, V.; Ribeiro, A.; Shumaker, J.; Benade, L.E. (Jerome H. Holland Laboratory, American Red Cross, Rockville, MD (USA))


    The ability of two fundamentally different photochemical procedures to inactivate model viruses in platelet suspensions was compared. Merocyanine 540 (MC 540) with visible light was used as an example of an oxygen-dependent chemical-directed at the viral membrane, and aminomethyl trimethyl psoralen (AMT) with ultraviolet A light (UVA) was used as an example of a nucleic acid-directed system. Antiviral conditions in petri dishes were identified and the effects of these procedures on platelet suspensions in plastic storage containers were studied. Concentrations of photochemicals in the 10 to 150 mumol range with 30 to 60 minutes of visible light (MC 540) or 1 to 2 minutes of UVA (AMT) readily inactivated 5 to 6 log10 of vesicular stomatitis virus (VSV) and other model viruses in platelet suspensions, provided the plasma concentration was reduced to about 15 percent by the use of a synthetic platelet storage medium. Extracellular pH, morphology scores, and aggregation response dropped markedly when platelets were treated with MC 540 and visible light. However, treatment with 136 mumol per L of AMT and 1 to 3 minutes of UVA could inactivate 5 log10 of VSV in platelet suspensions with retention of platelet characteristics for 4 days, particularly if oxygen levels were reduced during treatment. These studies demonstrate that AMT-UVA treatment meets the initial requirements for virus inactivation in platelet suspensions.

  4. Stereoselective Fluorescence Quenching in the Electron Transfer Photooxidation of Nucleobase-Related Azetidines by Cyanoaromatics

    Directory of Open Access Journals (Sweden)

    Ana B. Fraga-Timiraos


    Full Text Available Electron transfer involving nucleic acids and their derivatives is an important field in bioorganic chemistry, specifically in connection with its role in the photo-driven DNA damage and repair. Four-membered ring heterocyclic oxetanes and azetidines have been claimed to be the intermediates involved in the repair of DNA (6-4 photoproduct by photolyase. In this context, we examine here the redox properties of the two azetidine isomers obtained from photocycloaddition between 6-aza-1,3-dimethyluracil and cyclohexene. Steady-state and time-resolved fluorescence experiments using a series of photoreductants and photooxidants have been run to evaluate the efficiency of the electron transfer process. Analysis of the obtained quenching kinetics shows that the azetidine compounds can act as electron donors. Additionally, it appears that the cis isomer is more easily oxidized than its trans counterpart. This result is in agreement with electrochemical studies performed on both azetidine derivatives.

  5. High throughput photo-oxidations in a packed bed reactor system. (United States)

    Kong, Caleb J; Fisher, Daniel; Desai, Bimbisar K; Yang, Yuan; Ahmad, Saeed; Belecki, Katherine; Gupton, B Frank


    The efficiency gains produced by continuous-flow systems in conducting photochemical transformations have been extensively demonstrated. Recently, these systems have been used in developing safe and efficient methods for photo-oxidations using singlet oxygen generated by photosensitizers. Much of the previous work has focused on the use of homogeneous photocatalysts. The development of a unique, packed-bed photoreactor system using immobilized rose bengal expands these capabilities as this robust photocatalyst allows access to and elaboration from these highly useful building blocks without the need for further purification. With this platform we were able to demonstrate a wide scope of singlet oxygen ene, [4+2] cycloadditions and heteroatom oxidations. Furthermore, we applied this method as a strategic element in the synthesis of the high-volume antimalarial artemisinin. Copyright © 2017. Published by Elsevier Ltd.

  6. Controlling photo-oxidation processes of a polyfluorene derivative: The effect of additives and mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, G.R. [Laboratory of Polymers and Electronic Properties of Materials – UFOP, Ouro Preto, MG (Brazil); Nowacki, B. [Paulo Scarpa Polymer Laboratory – UFPR, Curitiba, PR (Brazil); Magalhães, A. [Instituto de Química, Universidade Estadual de Campinas – UNICAMP, Campinas, SP (Brazil); Azevedo, E.R. de [Instituto de Física de São Carlos, Universidade de São Paulo – USP, São Carlos, SP (Brazil); Sá, E.L. de [Chemistry Department, Federal University of Parana, Curitiba, PR (Brazil); Akcelrud, L.C. [Paulo Scarpa Polymer Laboratory – UFPR, Curitiba, PR (Brazil); Bianchi, R.F., E-mail: [Laboratory of Polymers and Electronic Properties of Materials – UFOP, Ouro Preto, MG (Brazil)


    The control of the photo degradation of a fluorene–vinylene–phenylene based-polymer, poly(9,9-di-hexylfluorenediylvinylene-alt-1,4-phenylenevinylene) (LaPPS16) was achieved by addition of a radical scavenger (RS) (enhancing photo resistance) or a radical initiator (RI) (reducing photo resistance). Photoluminescence, UV–Vis absorption, {sup 1}H NMR spectroscopies and gel permeation chromatography (GPC) revealed that the incorporating small amounts of RS or RI is an efficient way to control the rates of the photo-oxidation reactions, and thus to obtain the conjugated polymer with foreseeable degradation rates for applications in blue-light sensitive detectors for neonatal phototherapy. - Highlights: • Photo degradation control of a fluorene–vinylene–phenylene based polymer was achieved. • A radical scavenger enhanced photo resistance and radical initiator decreased it. • Color change rate with irradiation dose provided a basis for dosimeter construction.

  7. Photo-oxidation of EPDM/layered double hydroxides composites: Influence of layered hydroxides and stabilizers

    Directory of Open Access Journals (Sweden)


    Full Text Available The photo-oxidation of ethylene propylene diene monomer (EPDM/ layered double hydroxide (LDH composites as well as EPDM/LDH with stabilizers is studied under accelerated UV irradiation (λ≥290 nm at 60°C for different time intervals. The development of functional groups during oxidation was monitored by FT-IR spectroscopy. The photodegradation of the pristine polymer and composites take place and the increase in hydroxyl and carbonyl groups with irradiation times, was estimated. EPDM filled LDH showed higher degradation rate than pristine EPDM, while in acidic medium EPDM/LDH showed almost equal degradation as in isolated conditions. These results show the advantages of LDHs as a filler as well as an acid killer. The effect of stabilizers is very less because of their concentration in comparison of LDH.

  8. Photooxidation of Toluene: Correlation of Noble Metal Loading on Titania and Activation Energy

    Directory of Open Access Journals (Sweden)

    Haroon ur Rashid


    Full Text Available A series of platinum and palladium supported on titania catalysts were prepared by wet impregnation method with the Pt or Pd loading varying in the range of 0.1–1.2 weight percent. The catalysts were characterized by SEM, EDX, XRF, XRD, FT-IR, and BET surface area analysis. The catalysts were tested for their efficiency in the liquid phase solvent-free photooxidation of toluene to benzyl alcohol and benzaldehyde in the presence of molecular oxygen. The effect of noble metal contents on the activation energy was studied. Activation energy was found to be in a reciprocal relation to the platinum or palladium content of the catalyst. The percent conversion of toluene was observed to increase in response to an increase in the metal loading on titania. The apparent quantum yield, however, was independent of the platinum or palladium content of the catalyst.

  9. Photo-oxidation of PAHs with calcium peroxide as a source of the hydroxyl radicals

    Directory of Open Access Journals (Sweden)

    Kozak Jolanta


    Full Text Available The efficiency of the removal of selected PAHs from the pretreated coking wastewater with usage of CaO2, Fenton reagent (FeSO4 and UV rays are presented in this article. The investigations were carried out using coking wastewater originating from biological, industrial wastewater treatment plant. At the beginning of the experiment, the calcium peroxide (CaO2 powder as a source of hydroxyl radicals (OH• and Fenton reagent were added to the samples of wastewater. Then, the samples were exposed to UV rays for 360 s. The process was carried out at pH 3.5-3.8. After photo-oxidation process a decrease in the PAHs concentration was observed. The removal efficiency of selected hydrocarbons was in the ranged of 89-98%. The effectiveness of PAHs degradation was directly proportional to the calcium peroxide dose.

  10. Chemical characterization of organosulfates in secondary organic aerosol derived from the photooxidation of alkanes

    Directory of Open Access Journals (Sweden)

    M. Riva


    Full Text Available We report the formation of aliphatic organosulfates (OSs in secondary organic aerosol (SOA from the photooxidation of C10–C12 alkanes. The results complement those from our laboratories reporting the formation of OSs and sulfonates from gas-phase oxidation of polycyclic aromatic hydrocarbons (PAHs. Both studies strongly support the formation of OSs from the gas-phase oxidation of anthropogenic precursors, as hypothesized on the basis of recent field studies in which aromatic and aliphatic OSs were detected in fine aerosol collected from several major urban locations. In this study, dodecane, cyclodecane and decalin, considered to be important SOA precursors in urban areas, were photochemically oxidized in an outdoor smog chamber in the presence of either non-acidified or acidified ammonium sulfate seed aerosol. Effects of acidity and relative humidity on OS formation were examined. Aerosols collected from all experiments were characterized by ultra performance liquid chromatography coupled to electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-QTOFMS. Most of the OSs identified could be explained by formation of gaseous epoxide precursors with subsequent acid-catalyzed reactive uptake onto sulfate aerosol and/or heterogeneous reactions of hydroperoxides. The OSs identified here were also observed and quantified in fine urban aerosol samples collected in Lahore, Pakistan, and Pasadena, CA, USA. Several OSs identified from the photooxidation of decalin and cyclodecane are isobars of known monoterpene organosulfates, and thus care must be taken in the analysis of alkane-derived organosulfates in urban aerosol.

  11. Corrosion resistant three-dimensional nanotextured silicon for water photo-oxidation (United States)

    Carter, Rachel; Chatterjee, Shahana; Gordon, Evan; Share, Keith; Erwin, William R.; Cohn, Adam P.; Bardhan, Rizia; Pint, Cary L.


    We demonstrate the ability to chemically transform bulk silicon into a nanotextured surface that exhibits excellent electrochemical stability in aqueous conditions for water photo-oxidation. Conformal defective graphene coatings on nanotextured silicon formed by thermal treatment enable over 50× corrosion resistance in aqueous electrolytes based upon Tafel analysis and impedance spectroscopy. This enables nanotextured silicon as an effective oxygen-evolution photoanode for water splitting with saturation current density measured near 35 mA cm-2 under 100 mW cm-2 (1 sun) illumination. Our approach builds upon simple and scalable processing techniques with silicon to develop corrosion resistant electrodes that can benefit a broad range of catalytic and photocatalytic applications.We demonstrate the ability to chemically transform bulk silicon into a nanotextured surface that exhibits excellent electrochemical stability in aqueous conditions for water photo-oxidation. Conformal defective graphene coatings on nanotextured silicon formed by thermal treatment enable over 50× corrosion resistance in aqueous electrolytes based upon Tafel analysis and impedance spectroscopy. This enables nanotextured silicon as an effective oxygen-evolution photoanode for water splitting with saturation current density measured near 35 mA cm-2 under 100 mW cm-2 (1 sun) illumination. Our approach builds upon simple and scalable processing techniques with silicon to develop corrosion resistant electrodes that can benefit a broad range of catalytic and photocatalytic applications. Electronic supplementary information (ESI) available: (i) Experimental details, (ii) Nyquist plot from EIS data, (iii) FTIR of H-terminated silicon, (iv) reflectance measurements to quantify light trapping in nanotextured silicon, (v) LSV from Tafel analysis, and (vi) J-V curves for H-terminated flat samples, (vii) stability test of photoanode, and (viii) forward and reverse scans for each sample type. See DOI: 10

  12. Phytohormone Interaction Modulating Fruit Responses to Photooxidative and Heat Stress on Apple (Malus domestica Borkh.

    Directory of Open Access Journals (Sweden)

    Carolina A. Torres


    Full Text Available Sun-related physiological disorders such as sun damage on apples (Malus domestica Borkh are caused by cumulative photooxidative and heat stress during their growing season triggering morphological, physiological, and biochemical changes in fruit tissues not only while it is on the tree but also after it has been harvested. The objective of the work was to establish the interaction of auxin (indole-3-acetic acid; IAA, abscisic acid (ABA, jasmonic acid (JA, salicylic acid (SA, and ethylene (ET and its precursor ACC (free and conjugated, MACC during development of sun-injury-related disorders pre- and post-harvest on apples. Peel tissue was extracted from fruit growing under different sun exposures (Non-exposed, NE; Exposed, EX and with sun injury symptoms (Moderate, Mod. Sampling was carried out every 15 days from 75 days after full bloom (DAFB until 120 days post-harvest in cold storage (1°C, > 90%RH. Concentrations of IAA, ABA, JA, SA, were determined using UHPLC mass spectrometry, and ET and ACC (free and conjugated MACC using gas chromatography. IAA was found not to be related directly to sun injury development, but it decreased 60% in sun exposed tissue, and during fruit development. ABA, JA, SA, and ethylene concentrations were significantly higher (P ≤ 0.05 in Mod tissue, but their concentration, except for ethylene, were not affected by sun exposure. ACC and MACC concentrations increased until 105 DAFB in all sun exposure categories. During post-harvest, ethylene climacteric peak was delayed on EX compared to Mod. ABA and SA concentrations remained stable throughout storage in both tissue. JA dramatically increased post-harvest in both EX and Mod tissue, and orchards, confirming its role in low temperature tolerance. The results suggest that ABA, JA, and SA together with ethylene are modulating some of the abiotic stress defense responses on sun-exposed fruit during photooxidative and heat stress on the tree.

  13. Nrf2 protects photoreceptor cells from photo-oxidative stress induced by blue light. (United States)

    Chen, Wan-Ju; Wu, Caiying; Xu, Zhenhua; Kuse, Yoshiki; Hara, Hideaki; Duh, Elia J


    Oxidative stress plays a key role in age-related macular degeneration and hereditary retinal degenerations. Light damage in rodents has been used extensively to model oxidative stress-induced photoreceptor degeneration, and photo-oxidative injury from blue light is particularly damaging to photoreceptors. The endogenous factors protecting photoreceptors from oxidative stress, including photo-oxidative stress, are continuing to be elucidated. In this study, we evaluated the effect of blue light exposure on photoreceptors and its relationship to Nrf2 using cultured murine photoreceptor (661W) cells. 661W cells were exposed to blue light at 2500 lux. Exposure to blue light for 6-24 h resulted in a significant increase in intracellular reactive oxygen species (ROS) and death of 661W cells in a time-dependent fashion. Blue light exposure resulted in activation of Nrf2, as indicated by an increase in nuclear translocation of Nrf2. This was associated with a significant induction of expression of Nrf2 as well as an array of Nrf2 target genes, including antioxidant genes, as indicated by quantitative reverse transcription PCR (qRT-PCR). In order to determine the functional role of Nrf2, siRNA-mediated knockdown studies were performed. Nrf2-knockdown in 661W cells resulted in significant exacerbation of blue light-induced reactive oxygen species levels as well as cell death. Taken together, these findings indicate that Nrf2 is an important endogenous protective factor against oxidative stress in photoreceptor cells. This suggests that drugs targeting Nrf2 could be considered as a neuroprotective strategy for photoreceptors in AMD and other retinal conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Secondary organic aerosol formation from photo-oxidation of unburned fuel: experimental results and implications for aerosol formation from combustion emissions. (United States)

    Jathar, Shantanu H; Miracolo, Marissa A; Tkacik, Daniel S; Donahue, Neil M; Adams, Peter J; Robinson, Allen L


    We conducted photo-oxidation experiments in a smog chamber to investigate secondary organic aerosol (SOA) formation from eleven different unburned fuels: commercial gasoline, three types of jet fuel, and seven different diesel fuels. The goals were to investigate the influence of fuel composition on SOA formation and to compare SOA production from unburned fuel to that from diluted exhaust. The trends in SOA production were largely consistent with differences in carbon number and molecular structure of the fuel, i.e., fuels with higher carbon numbers and/or more aromatics formed more SOA than fuels with lower carbon numbers and/or substituted alkanes. However, SOA production from different diesel fuels did not depend strongly on aromatic content, highlighting the important contribution of large alkanes to SOA formation from mixtures of high carbon number (lower volatility) precursors. In comparison to diesels, SOA production from higher volatility fuels such as gasoline appeared to be more sensitive to aromatic content. On the basis of a comparison of SOA mass yields (SOA mass formed per mass of fuel reacted) and SOA composition (as measured by an aerosol mass spectrometer) from unburned fuels and diluted exhaust, unburned fuels may be reasonable surrogates for emissions from uncontrolled engines but not for emissions from engines with after treatment devices such as catalytic converters.

  15. Impact of nano/micron vegetable carbon black on mechanical, barrier and anti-photooxidation properties of fish gelatin film. (United States)

    Ding, Junsheng; Wu, Xiaomeng; Qi, Xiaona; Guo, Heng; Liu, Anjun; Wang, Wenhang


    In this paper, two kinds of commonly used vegetable carbon black (VCB, 3000 mesh; nano) at 50 g kg -1 concentration (based on dried gelatin) were added to 48 g kg -1 of fish gelatin (GEL) solutions and their effects on mechanical, barrier and anti-photooxidation properties of GEL films were investigated. From the SEM images, it was shown that compared with 3000 mesh VCB (1-2 μm), nano VCB (100-200 nm) made the microstructure of GEL film more compact and more gelatin chains were cross-linked by nano VCB. The addition of nano VCB significantly increased gelatin film strength with the greatest tensile strength of 52.589 MPa and stiffness with the highest Young's modulus of 968.874 MPa, but led to the reduction of film elongation. Also, the VCB presence significantly improved water vapour and oxygen barrier properties of GEL film. Importantly, nano VCB increased GEL film with better UV barrier property due to its stronger UV absorption nature when compared with micron VCB. This property could help in the preservation of oil samples in the photooxidation accelerated test. With improved properties, the nano VCB-reinforced GEL film may have great potential for application in the edible packaging field, especially for the anti-photooxidation property. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  16. The effects of a solar eclipse on photo-oxidants in different areas of China

    Directory of Open Access Journals (Sweden)

    J.-B. Wu


    Full Text Available This study investigates the effects of the total solar eclipse of 22 July 2009 on surface ozone and other photo-oxidants over China. A box model was used to study the sensitivity of ozone to the limb darkening effect during an eclipse event, and to show that the impact on ozone is small (less than 0.5 %. In addition, the regional model WRF-Chem was applied to study the effects of the eclipse on meteorological and chemical parameters, focusing on different regions in China. Chemical and meteorological observations were used to validate the model and to show that it can capture the effects of the total solar eclipse well. Model calculations show distinct differences in the spatial distributions of meteorological and chemical parameters with and without the eclipse. The maximum impacts of the eclipse occur over the area of totality, where there is a decrease in surface temperature of 1.5 °C and decrease in wind speed of 1 m s−1. The maximum impacts on atmospheric pollutants occur over parts of north and east China where emissions are greater, with an increase of 5 ppbv in NO2 and 25 ppbv in CO and a decrease of 10 ppbv in O3 and 4 ppbv in NO. This study also demonstrates the effects of the solar eclipse on surface photo-oxidants in different parts of China. Although the sun was obscured to a smaller extent in polluted areas than in clean areas, the impacts of the eclipse in polluted areas are greater and last longer than they do in clean areas. In contrast, the change in radical concentrations (OH, HO2 and NO3 in clean areas is much larger than in polluted areas mainly because of the limited source of radicals in these areas. The change in radical concentrations during the eclipse reveals that nighttime chemistry dominates in both clean and polluted areas. As solar eclipses provide a natural opportunity to test more thoroughly our understanding of atmospheric chemistry, especially that

  17. FTIR spectroscopy of the reaction center of Chloroflexus aurantiacus: photooxidation of the primary electron donor. (United States)

    Zabelin, A A; Shkuropatova, V A; Shuvalov, V A; Shkuropatov, A Ya


    Photochemical oxidation of the primary electron donor P in reaction centers (RCs) of the filamentous anoxygenic phototrophic bacterium Chloroflexus (C.) aurantiacus was examined by light-induced Fourier transform infrared (FTIR) difference spectroscopy at 95 K in the spectral range of 4000-1200 cm(-1). The light-induced P(+)Q(A)(-)/PQ(A) IR spectrum of C. aurantiacus RCs is compared to the well-characterized FTIR difference spectrum of P photooxidation in the purple bacterium Rhodobacter (R.) sphaeroides R-26 RCs. The presence in the P(+)Q(A)(-)/PQ(A) FTIR spectrum of C. aurantiacus RCs of specific low-energy electronic transitions at ~2650 and ~2200 cm(-1), as well as of associated vibrational (phase-phonon) bands at 1567, 1481, and 1294-1285 cm(-1), indicates that the radical cation P(+) in these RCs has dimeric structure, with the positive charge distributed between the two coupled bacteriochlorophyll a molecules. The intensity of the P(+) absorbance band at ~1250 nm (upon chemical oxidation of P at room temperature) in C. aurantiacus RCs is approximately 1.5 times lower than that in R. sphaeroides R-26 RCs. This fact, together with the decreased intensity of the absorbance band at ~2650 cm(-1), is interpreted in terms of the weaker coupling of bacteriochlorophylls in the P(+) dimer in C. aurantiacus compared to R. sphaeroides R-26. In accordance with the previous (pre)resonance Raman data, FTIR measurements in the carbonyl stretching region show that in C. aurantiacus RCs (i) the 13(1)-keto C=O groups of P(A) and P(B-) molecules constituting the P dimer are not involved in hydrogen bonding in either neutral or photooxidized state of P and (ii) the 3(1)-acetyl C=O group of P(B) forms a hydrogen bond (probably with tyrosine M187) absorbing at 1635 cm(-1). Differential signals at 1757(+)/1749(-) and 1741(+)/1733(-) cm(-1) in the FTIR spectrum of C. aurantiacus RCs are attributed to the 13(3)-ester C=O groups of P in different environments.

  18. Optical properties of secondary organic aerosols generated by photooxidation of aromatic hydrocarbons. (United States)

    Li, Kun; Wang, Weigang; Ge, Maofa; Li, Jiangjun; Wang, Dong


    The refractive index (RI) is the fundamental characteristic that affects the optical properties of aerosols, which could be some of the most important factors influencing direct radiative forcing. The secondary organic aerosols (SOAs) generated by the photooxidation of benzene, toluene, ethylbenzene and m-xylene (BTEX) under low-NOx and high-NOx conditions are explored in this study. The particles generated in our experiments are considered to be spherical, based on atomic force microscopy (AFM) images, and nonabsorbent at a wavelength of 532 nm, as determined by ultraviolet-visible light (UV-Vis) spectroscopy. The retrieved RIs at 532 nm for the SOAs range from 1.38-1.59, depending on several factors, such as different precursors and NOx levels. The RIs of the SOAs are altered differently as the NOx concentration increases as follows: the RIs of the SOAs derived from benzene and toluene increase, whereas those of the SOAs derived from ethylbenzene and m-xylene decrease. Finally, by comparing the experimental data with the model values, we demonstrate that the models likely overestimate the RI values of the SOA particles to a certain extent, which in turn overestimates the global direct radiative forcing of the organic particles.

  19. Immunological Detection of N-formylkynurenine in Porphyrin-Mediated Photooxided Lens α-crystallin (United States)

    Ehrenshaft, Marilyn; Zhao, Baozhong; Andley, Usha P.; Mason, Ronald P.; Roberts, Joan E.


    Crystallin proteins are responsible for maintaining lens transparency and allowing the lens to focus light undistorted onto the retina. The α-crystallins are the major lens crystallins, and function as both structural proteins and chaperones to protect all lens proteins from damage leading to lens deterioration. Because lens crystallin proteins do not turn over, the damage they accumulate can lead to cataracts, the world’s leading cause of blindness. Photosensitizing porphyrins can accumulate in the eye through either endogenous metabolism or through therapeutic or diagnostic procedures. Porphyrin buildup exacerbates lens aging through increased levels of singlet oxygen, resulting in protein polymerization and amino acid residue alteration. Tryptophans oxidize to kynurenine and N-formylkynurenine (NFK) causing irreversible changes in the refractive index of the normally transparent lens, leading to development of cataracts. Additionally, NFK is itself a photosensitizer, and its presence exacerbates lens deterioration. This work uses anti-NFK antiserum to study porphyrin-facilitated photooxidation of α-crystallin tryptophan residues. In vitro experiments show that four biologically interesting porphyrins mediate α-crystallin polymerization and accumulation of both protein radicals and NFK. Confocal microscopy of cultured human lens epithelial cells indicates that while all four porphyrins photosensitize cellular proteins, not all oxidize the tryptophans of cellular α-crystallin to NFK. PMID:21770952

  20. Effects of NOx on the volatility of secondary organic aerosol from isoprene photooxidation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Lu; Kollman, Matthew S.; Song, Chen; Shilling, John E.; Ng, L. N.


    The effects of NOx on the volatility of the secondary organic aerosol (SOA) formed from isoprene photooxidation are investigated in environmental chamber experiments. Two types of experiments are performed. In HO2-dominant experiments, organic peroxy radicals (RO2) primarily react with HO2. In mixed experiments, RO2 reacts through multiple pathways. The volatility and oxidation state of isoprene SOA is sensitive to and displays a non-linear dependence on NOx levels. When initial NO/isoprene ratio is approximately 3 (ppbv:ppbv), SOA are shown to be most oxidized and least volatile, associated with the highest SOA yield. A High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) is applied to characterize the key chemical properties of aerosols. While the composition of SOA in mixed experiments does not change substantially over time, SOA become less volatile and more oxidized as oxidation progresses in HO2-dominant experiments. Analysis of the SOA composition suggests that the further reactions of organic peroxides and alcohols may produce carboxylic acids, which might play a strong role in SOA aging.

  1. The Effect of Transition Metal Doping on the Photooxidation Process of Titania-Clay Composites

    Directory of Open Access Journals (Sweden)

    Judit Ménesi


    Full Text Available Montmorillonite-TiO2 composites containing various transition metal ions (silver, copper, or nickel were prepared, and their photocatalytic efficiencies were tested in the degradation of ethanol vapor at 70% relative humidity. Two light sources, UV-rich ( = 254 nm and visible ( = 435 nm, were used. The kinetics of degradation was monitored by gas chromatography. It was established that, in the case of each catalyst, ethanol degradation was more efficient in UV-C ( = 254 nm than in visible light, furthermore, these samples containing silver or copper ions were in each case about twice more efficient than P25 TiO2 (Degussa AG. used as a reference. In photooxidation by visible light, TiO2/clay samples doped with silver or copper were also more efficient than the reference sample, P25 TiO2. We show that doping metal ions can also be delivered to the surface of the support by ion exchange and significantly alters the optical characteristics of the TiO2/clay composite.

  2. SU-C-204-06: Monte Carlo Dose Calculation for Kilovoltage X-Ray-Psoralen Activated Cancer Therapy (X-PACT): Preliminary Results

    Energy Technology Data Exchange (ETDEWEB)

    Mein, S [Duke University Medical Physics Graduate Program (United States); Gunasingha, R [Department of Radiation Safety, Duke University Medical Center (United States); Nolan, M [Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University (United States); Oldham, M; Adamson, J [Department of Radiation Oncology, Duke University Medical Center (United States)


    promise for accurate quantification of dose for this novel psoralen X-ray therapy. Funding Support, Disclosures, & Conflict of Interest: The Monte Carlo simulation work was not funded; Drs. Adamson & Oldham have received funding from Immunolight LLC for X-PACT research.

  3. The Caltech Photooxidation Flow Tube reactor: design, fluid dynamics and characterization (United States)

    Huang, Yuanlong; Coggon, Matthew M.; Zhao, Ran; Lignell, Hanna; Bauer, Michael U.; Flagan, Richard C.; Seinfeld, John H.


    Flow tube reactors are widely employed to study gas-phase atmospheric chemistry and secondary organic aerosol (SOA) formation. The development of a new laminar-flow tube reactor, the Caltech Photooxidation Flow Tube (CPOT), intended for the study of gas-phase atmospheric chemistry and SOA formation, is reported here. The present work addresses the reactor design based on fluid dynamical characterization and the fundamental behavior of vapor molecules and particles in the reactor. The design of the inlet to the reactor, based on computational fluid dynamics (CFD) simulations, comprises a static mixer and a conical diffuser to facilitate development of a characteristic laminar flow profile. To assess the extent to which the actual performance adheres to the theoretical CFD model, residence time distribution (RTD) experiments are reported with vapor molecules (O3) and submicrometer ammonium sulfate particles. As confirmed by the CFD prediction, the presence of a slight deviation from strictly isothermal conditions leads to secondary flows in the reactor that produce deviations from the ideal parabolic laminar flow. The characterization experiments, in conjunction with theory, provide a basis for interpretation of atmospheric chemistry and SOA studies to follow. A 1-D photochemical model within an axially dispersed plug flow reactor (AD-PFR) framework is formulated to evaluate the oxidation level in the reactor. The simulation indicates that the OH concentration is uniform along the reactor, and an OH exposure (OHexp) ranging from ˜ 109 to ˜ 1012 molecules cm-3 s can be achieved from photolysis of H2O2. A method to calculate OHexp with a consideration for the axial dispersion in the present photochemical system is developed.

  4. Continuous Photo-Oxidation in a Vortex Reactor: Efficient Operations Using Air Drawn from the Laboratory. (United States)

    Lee, Darren S; Amara, Zacharias; Clark, Charlotte A; Xu, Zeyuan; Kakimpa, Bruce; Morvan, Herve P; Pickering, Stephen J; Poliakoff, Martyn; George, Michael W


    We report the construction and use of a vortex reactor which uses a rapidly rotating cylinder to generate Taylor vortices for continuous flow thermal and photochemical reactions. The reactor is designed to operate under conditions required for vortex generation. The flow pattern of the vortices has been represented using computational fluid dynamics, and the presence of the vortices can be easily visualized by observing streams of bubbles within the reactor. This approach presents certain advantages for reactions with added gases. For reactions with oxygen, the reactor offers an alternative to traditional setups as it efficiently draws in air from the lab without the need specifically to pressurize with oxygen. The rapid mixing generated by the vortices enables rapid mass transfer between the gas and the liquid phases allowing for a high efficiency dissolution of gases. The reactor has been applied to several photochemical reactions involving singlet oxygen ((1)O2) including the photo-oxidations of α-terpinene and furfuryl alcohol and the photodeborylation of phenyl boronic acid. The rotation speed of the cylinder proved to be key for reaction efficiency, and in the operation we found that the uptake of air was highest at 4000 rpm. The reactor has also been successfully applied to the synthesis of artemisinin, a potent antimalarial compound; and this three-step synthesis involving a Schenk-ene reaction with (1)O2, Hock cleavage with H(+), and an oxidative cyclization cascade with triplet oxygen ((3)O2), from dihydroartemisinic acid was carried out as a single process in the vortex reactor.

  5. Selective photooxidation of small hydrocarbons by O{sub 2} in zeolites with visible light

    Energy Technology Data Exchange (ETDEWEB)

    Frei, H.; Blatter, F.; Sun, F. [Lawrence Berkeley Lab., CA (United States)


    Small alkenes, alkanes, or substituted aromatics loaded with O{sub 2} from the gas phase into alkali or alkaline-earth exchanged zeolite Y react upon irradiation with visible light to form organic building blocks and industrial intermediates. Examples include the conversion of propylene to acrolein, toluene to benzaldehyde, cyclohexane to cyclohexanone, and propane and ethane to acetone and acetaldehyde, respectively. Corresponding alkyl (allyl) hydroperoxide intermediates were observed by in situ FT-infrared spectroscopy. A key finding is that the selectivity of these oxidations is very high even at high conversion, a feature that is lacking existing methods of thermal catalytic autoxidation. Reaction quantum efficiencies are rather high, typically between 0.1 and 0.3. The origin of the photochemistry is a hydrocarbon{sm_bullet}O{sub 2} charge-transfer absorption that extends into the visible region. This was discovered by reaction excitation spectroscopy and confirmed by diffuse reflectance measurements. It signals an unprecedented 1.5-2.5 eV stabilization of the excited hydrocarbon{sm_bullet}O{sub 2} charge-transfer state by the zeolite environment relative to the gas or solution phase. The stabilization is attributed to the very high electrostatic field inside the supercage of zeolite Y, which has been measured by the absorption intensity of the induced infrared fundamental of N{sub 2} (NaY, 0.2 V{Angstrom}{sup -1}, BaY, 0.5 V{Angstrom}{sup -1}). The alkane photooxidations by O{sub 2} open up a new method for very mild C-H activation.

  6. Identification of 4-hydroxynonenal-modified retinal proteins induced by photooxidative stress prior to retinal degeneration. (United States)

    Tanito, Masaki; Haniu, Hisao; Elliott, Michael H; Singh, Anil K; Matsumoto, Hiroyuki; Anderson, Robert E


    4-Hydroxynonenal (4-HNE) is a reactive aldehyde species generated endogenously from the nonenzymatic oxidation of n-6 polyunsaturated fatty acids under physiological conditions. We have reported that intense white light exposure increases 4-HNE-protein modification in the retina prior to the onset of photoreceptor cell apoptosis. To understand the molecular mechanism(s) underlying the retinal degeneration induced by photooxidative stress, we identified 4-HNE-modified retinal proteins using a proteomic approach. Albino rats were exposed to 5 k lx white fluorescent light for 3 h and retinas were removed 24 h later and pooled. By Western dot blot analysis, the total intensity of 4-HNE-modified proteins was increased 1.5-fold following the exposure compared to dim light controls. In two independent sets of two-dimensional gel electrophoresis/Western blots followed by peptide mass fingerprinting (PMF), nine proteins including voltage-dependent anion channel, enolase 1alpha, aldolase C, crystallins alphaA and betaB3, heterogeneous nuclear ribonucleoprotein A2/B1, albumin, and glutamine synthetase were identified. We observed that 4-HNE modifications of retinal proteins are specific to a particular set of proteins rather than random events on abundant proteins. By immunohistochemistry, localization of 3 identified proteins overlapped with immunoreactivity of 4-HNE-modified proteins in light-exposed retinas. Intense light exposure increases 4-HNE-protein modifications on specific retinal proteins in several functional categories including energy metabolism, glycolysis, chaperone, phototransduction, and RNA processing. Together with previous reports that 4-HNE modification changes protein activities, these results suggest a close association of 4-HNE-protein modifications with the initiation of light-induced retinal degeneration.

  7. Continuous Photo-Oxidation in a Vortex Reactor: Efficient Operations Using Air Drawn from the Laboratory (United States)


    We report the construction and use of a vortex reactor which uses a rapidly rotating cylinder to generate Taylor vortices for continuous flow thermal and photochemical reactions. The reactor is designed to operate under conditions required for vortex generation. The flow pattern of the vortices has been represented using computational fluid dynamics, and the presence of the vortices can be easily visualized by observing streams of bubbles within the reactor. This approach presents certain advantages for reactions with added gases. For reactions with oxygen, the reactor offers an alternative to traditional setups as it efficiently draws in air from the lab without the need specifically to pressurize with oxygen. The rapid mixing generated by the vortices enables rapid mass transfer between the gas and the liquid phases allowing for a high efficiency dissolution of gases. The reactor has been applied to several photochemical reactions involving singlet oxygen (1O2) including the photo-oxidations of α-terpinene and furfuryl alcohol and the photodeborylation of phenyl boronic acid. The rotation speed of the cylinder proved to be key for reaction efficiency, and in the operation we found that the uptake of air was highest at 4000 rpm. The reactor has also been successfully applied to the synthesis of artemisinin, a potent antimalarial compound; and this three-step synthesis involving a Schenk-ene reaction with 1O2, Hock cleavage with H+, and an oxidative cyclization cascade with triplet oxygen (3O2), from dihydroartemisinic acid was carried out as a single process in the vortex reactor. PMID:28781513

  8. Topical or oral administration with an extract of Polypodium leucotomos prevents acute sunburn and psoralen-induced phototoxic reactions as well as depletion of Langerhans cells in human skin

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, S.; Pathak, M.A.; Fitzpatrick, T.B. [Massachusetts General Hospital, Harvard Medical School, Dept. of Dermatology, Boston, MA (United States); Cuevas, J. [Hospital Universitario de Guadalajara, Dept. of Pathology, Guadalajara (Spain); Villarrubia, V.G. [I.F. Cantabria SA, Medical Dept., Immunology Sect., Madrid (Spain)


    Sunburn, immune suppression, photo-aging, and skin cancers result from uncontrolled overexposure of human skin to solar ultraviolet radiation (UVR). Preventive measures, including photo-protection, are helpful and can be achieved by topical sun-screening agents. Polypodium leucotomos (PL) has been used for the treatment of inflammatory diseases and has shown some in vitro and in vivo immunomodulating properties. Its beneficial photo-protective effects in the treatment of vitiligo and its antioxidant properties encouraged us to evaluate in vivo the potentially useful photo-protective property of natural extract of PL after topical application or oral ingestion. Twenty-one healthy volunteers [either untreated or treated with oral psoralens (8-MOP or 5-MOP)] were enrolled in this study and exposed to solar radiation for evaluation of the following clinical parameters: immediate pigment darkening (IPD), minimal erythema dose (MED), minimal melanogenic dose (MMD), and minimal phototoxic dose (MPD) before and after topical or oral administration of PL. Immunohistochemical assessment of CD1a-expressing epidermal cells were also performed. PL was found to be photo-protective after topical application as well as oral administration. PL increased UV dose required for IPD (P<0.01), MED (P<0.001) and MPD (P<0.001). After oral administration of PL, MED increased 2.,8{+-}0.59 times and MPD increased 2.75{+-}0.5 and 6.8{+-}1.3 times depending upon the type of psoralen used. Immunohistochemical study revealed photo-protection of Langherhans cells by oral as well as topical PL. The observed photo-protective activities of oral or topical PL reveal a new avenue in examining the potentially useful field of systemic photo-protection and suggests that PL can be used as adjunct treatment and can make photochemotherapy and phototherapy possibly safe and effective when the control of cutaneous phototoxicity to PUVA or UVB is a limiting factor in such photo-therapies. (au). 50 refs.

  9. Photophysical and photochemical effects of UV and VUV photo-oxidation and photolysis on PET and PEN (United States)

    Morgan, Andrew

    Polyethylene Terephthalate (PET) is a widely used polymer in the bottling, packaging, and clothing industry. In recent years an increasing global demand for PET has taken place due to the Solar Disinfection (SODIS) process. SODIS is a method of sterilizing fresh water into drinkable water. The PET bottles are used in the process to contain the water during solar irradiation due to its highly transparent optical property. Alongside PET, polyethylene 2,6-napthalate (PEN) is used in bottling and flexible electronic applications. The surface of PEN would need to be modified to control the hydrophilicity and the interaction it exudes as a substrate. The UV light absorption properties of PET and PEN are of great importance for many applications, and thus needs to be studied along with its photochemical resistance. The optical and chemical nature of PET was studied as it was treated by UV photo-oxidation, photo-ozonation, and photolysis under atmospheric pressure. Another investigation was also used to study PEN and PET as they are treated by vacuum UV (VUV) photo-oxidation, VUV photolysis, and remote oxygen reactions. The extent of the photoreactions' effect into the depth of the polymers is examined as treatment conditions are changed. The different experimental methods established the rate of several competing photoreactions on PET and PEN during irradiance, and their effect on the optical quality of the polymers.

  10. Dithiothreitol activity by particulate oxidizers of SOA produced from photooxidation of hydrocarbons under varied NOx levels

    Directory of Open Access Journals (Sweden)

    H. Jiang


    Full Text Available When hydrocarbons (HCs are atmospherically oxidized, they form particulate oxidizers, including quinones, organic hydroperoxides, and peroxyacyl nitrates (PANs. These particulate oxidizers can modify cellular materials (e.g., proteins and enzymes and adversely modulate cell functions. In this study, the contribution of particulate oxidizers in secondary organic aerosols (SOAs to the oxidative potential was investigated. SOAs were generated from the photooxidation of toluene, 1,3,5-trimethylbenzene, isoprene, and α-pinene under varied NOx levels. Oxidative potential was determined from the typical mass-normalized consumption rate (reaction time t =  30 min of dithiothreitol (DTTt, a surrogate for biological reducing agents. Under high-NOx conditions, the DTTt of toluene SOA was 2–5 times higher than that of the other types of SOA. Isoprene DTTt significantly decreased with increasing NOx (up to 69 % reduction by changing the HC ∕ NOx ratio from 30 to 5. The DTTt of 1,3,5-trimethylbenzene and α-pinene SOA was insensitive to NOx under the experimental conditions of this study. The significance of quinones to the oxidative potential of SOA was tested through the enhancement of DTT consumption in the presence of 2,4-dimethylimidazole, a co-catalyst for the redox cycling of quinones; however, no significant effect of 2,4-dimethylimidazole on modulation of DTT consumption was observed for all SOA, suggesting that a negligible amount of quinones was present in the SOA of this study. For toluene and isoprene, mass-normalized DTT consumption (DTTm was determined over an extended period of reaction time (t =  2 h to quantify their maximum capacity to consume DTT. The total quantities of PANs and organic hydroperoxides in toluene SOA and isoprene SOA were also measured using the Griess assay and the 4-nitrophenylboronic acid assay, respectively. Under the NOx conditions (HC ∕ NOx ratio: 5–36 ppbC ppb−1 applied in

  11. Cloud droplet activation of mixed organic-sulfate particles produced by the photooxidation of isoprene

    Directory of Open Access Journals (Sweden)

    S. M. King


    Full Text Available The cloud condensation nuclei (CCN properties of ammonium sulfate particles mixed with organic material condensed during the hydroxyl-radical-initiated photooxidation of isoprene (C5H8 were investigated in the continuous-flow Harvard Environmental Chamber. CCN activation curves were measured for organic particle mass concentrations of 0.5 to 10.0 μg m−3, NOx concentrations from under 0.4 ppbv up to 38 ppbv, particle mobility diameters from 70 to 150 nm, and thermodenuder temperatures from 25 to 100 °C. At 25 °C, the observed CCN activation curves were accurately described by a Köhler model having two internally mixed components, namely ammonium sulfate and secondary organic material. The modeled physicochemical parameters of the organic material were equivalent to an effective hygroscopicity parameter κORG of 0.10±0.03, regardless of the C5H8:NOx concentration ratio for the span of >200:0.4 to 50:38 (ppbv:ppbv. The volatilization curves (i.e., plots of the residual organic volume fraction against temperature were also similar for the span of investigated C5H8:NOx ratios, suggesting a broad similarity of particle chemical composition. This suggestion was supported by limited variance at 25 °C among the particle mass spectra. For example, the signal intensity at m/z 44 (which can result from the fragmentation of oxidized molecules believed to affect hygroscopicity and CCN properties varied weakly from 6 to 9% across the range of investigated conditions. In contradistinction to the results for 25 °C, conditioning up to 100 °C in the thermodenuder significantly reduced CCN activity. The altered CCN activity might be explained by chemical reactions (e.g., decomposition or oligomerization of the secondary organic material at elevated temperatures. The study's results at 25 °C, in conjunction with the results of

  12. Visible light photo-oxidations in the presence of alpha-Bi(2)O(3). (United States)

    Eberl, Joachim; Kisch, Horst


    alpha-Bismuth oxides of specific surface areas of 1-3 m(2) g(-1) were prepared by three different methods and their visible light activity was tested in the photodegradation (lambda>or= 420 nm) of 4-chlorophenol. In method A, which led to powders of poor to moderate photoactivity, the starting materials BiONO(3), Bi(NO(3))(3) x 5H(2)O, (BiO)(2)CO(3), and BiOCl were annealed at 500 degrees C without any pretreatment. In method B the salt (BiO)(2)CO(3) was washed with water and subsequently calcined at 450 degrees C affording a very active powder. In method C the salts BiONO(3), Bi(NO(3))(3) x 5H(2)O and (BiO)(2)CO(3) were dissolved in nitric acid and Bi(OH)(3) was precipitated by addition of sodium hydroxide. After annealing at 500 degrees C the resulting oxides exhibited moderate activity in the case of the (BiO)(2)CO(3) precursor whereas highly active powders were obtained from BiONO(3) and Bi(NO(3))(3) x 5H(2)O inducing almost complete photomineralization of 4-chlorophenol. XRD analysis indicated the presence of 40-140 nm large crystallites of alpha-Bi(2)O(3). From diffuse reflectance spectroscopy bandgaps of 2.80 +/- 0.05 eV and 2.93 +/- 0.05 eV were obtained, assuming an indirect or direct semiconductor, respectively. The quasi-Fermi potential of electrons at pH 7 was determined as -0.08 +/- 0.05 V (vs. NHE) through pH dependent photovoltage measurements. Repeated use of the presumed catalyst powder revealed that the mineralization is not a catalytic but a bismuth oxide assisted photo-oxidation. This result shed a critical light on previous reports on the photocatalytic action of binary and ternary bismuth oxides.

  13. Photo-oxidative degradation of motorcycle helmets in Hanoi, Vietnam: A prospective preliminary study. (United States)

    Ramli, Roszalina; Che Man, Zuraidah; Nordin, Rifqah; Abdul Karim, Fadzlina; Rashdi, Muhd Fazlynizam; Oxley, Jennie; Viet Cuong, Pham


    Vietnamese spend hours travelling on the road using their motorcycles. Their helmets are exposed continuously to sunlight and rain. The objectives of this study were to determine the association between the effect of photo-oxidative degradation (POD) of the outer shells and helmet age on helmet damage. The micro-structural change of the outer shell was also investigated. This was a prospective, cross sectional study recruiting injured motorcyclists from Hanoi, Vietnam hospital. The participants were interviewed by a trained researcher. The participants' helmets were collected post-crash. Initially, the helmets were examined for their type and external characteristics. A 3 cm × 3 cm cut was made on the helmet in the impacted and non-impacted areas (control). These areas were investigated for evidence of POD and presence of micro-cracks and material disintegration. 50 participants were enrolled. Sources of information included questionnaire and laboratory analyses. The helmet factors of interest were age of the helmet, exposure of helmet to sunlight and rain (duration/day) and history of previous impact. Laboratory analyses included Fourier Transform Infra Red (FTIR) for degradation and scanning electron microscopy (SEM) for micro-structural examination. Majority of the helmets was the open-face type, 40 (80.0%). 31 (62.0%) helmets aged less than three years (LTY) and 19 (38.0%) were three years old or more (MTY). 19 (61.3%) of the LTY helmets and 12 (63.2%) MTY helmets showed evidence of POD. The duration of helmet exposure to sunlight was between 93 to 6570 hours (mean 2347.74 hours; SD 1733.39). The SEM showed 15 helmets (30%) with micro-fractures, 21 helmets (42.0%) with material disintegration. Prolonged uv exposure to the ABS helmets resulted in changes in the helmet material in the form of material disintegration and microcracks and this association was statistically significant (p = 0.03). POD occurs due to routine exposure to the ultraviolet light

  14. Dithiothreitol activity by particulate oxidizers of SOA produced from photooxidation of hydrocarbons under varied NOx levels (United States)

    Jiang, Huanhuan; Jang, Myoseon; Yu, Zechen


    When hydrocarbons (HCs) are atmospherically oxidized, they form particulate oxidizers, including quinones, organic hydroperoxides, and peroxyacyl nitrates (PANs). These particulate oxidizers can modify cellular materials (e.g., proteins and enzymes) and adversely modulate cell functions. In this study, the contribution of particulate oxidizers in secondary organic aerosols (SOAs) to the oxidative potential was investigated. SOAs were generated from the photooxidation of toluene, 1,3,5-trimethylbenzene, isoprene, and α-pinene under varied NOx levels. Oxidative potential was determined from the typical mass-normalized consumption rate (reaction time t = 30 min) of dithiothreitol (DTTt), a surrogate for biological reducing agents. Under high-NOx conditions, the DTTt of toluene SOA was 2-5 times higher than that of the other types of SOA. Isoprene DTTt significantly decreased with increasing NOx (up to 69 % reduction by changing the HC / NOx ratio from 30 to 5). The DTTt of 1,3,5-trimethylbenzene and α-pinene SOA was insensitive to NOx under the experimental conditions of this study. The significance of quinones to the oxidative potential of SOA was tested through the enhancement of DTT consumption in the presence of 2,4-dimethylimidazole, a co-catalyst for the redox cycling of quinones; however, no significant effect of 2,4-dimethylimidazole on modulation of DTT consumption was observed for all SOA, suggesting that a negligible amount of quinones was present in the SOA of this study. For toluene and isoprene, mass-normalized DTT consumption (DTTm) was determined over an extended period of reaction time (t = 2 h) to quantify their maximum capacity to consume DTT. The total quantities of PANs and organic hydroperoxides in toluene SOA and isoprene SOA were also measured using the Griess assay and the 4-nitrophenylboronic acid assay, respectively. Under the NOx conditions (HC / NOx ratio: 5-36 ppbC ppb-1) applied in this study, the amount of organic hydroperoxides was

  15. Size Controlled Two-dimensional Co3O4 with Exposure of {111} Plane: Synthesis and Catalytic Properties for Photooxidation of Organics (United States)

    The size controlled 2D hexagonal structured Co3O4 with exposure of the {111} plane was fabricated, and the catalytic properties for photooxidation of organics using as-prepared samples were investigated. 2D hexagonal structured Co3O4 with the size of 3 m displays higher photocat...

  16. VUV photoionization aerosol mass spectrometric study on the iodine oxide particles formed from O3-initiated photooxidation of diiodomethane (CH2I2)

    Czech Academy of Sciences Publication Activity Database

    Wei, N.; Hu, Ch.; Zhou, S.; Ma, Q.; Mikuška, Pavel; Večeřa, Zbyněk; Gai, Y.; Lin, X.; Gu, X.; Zhao, W.; Fang, B.; Zhang, W.; Chen, J.; Liu, F.; Shan, X.; Sheng, L.


    Roč. 7, č. 89 (2017), s. 56779-56787 ISSN 2046-2069 Institutional support: RVO:68081715 Keywords : iodine oxide particles * photooxidation * aerosol mass spectrometer Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 3.108, year: 2016

  17. Differentiating the roles of photooxidation and biodegradation in the weathering of Light Louisiana Sweet crude oil in surface water from the Deepwater Horizon site. (United States)

    Bacosa, Hernando P; Erdner, Deana L; Liu, Zhanfei


    We determined the contributions of photooxidation and biodegradation to the weathering of Light Louisiana Sweet crude oil by incubating surface water from the Deepwater Horizon site under natural sunlight and temperature conditions. N-alkane biodegradation rate constants were ca. ten-fold higher than the photooxidation rate constants. For the 2-3 ring and 4-5 ring polycyclic aromatic hydrocarbons (PAHs), photooxidation rate constants were 0.08-0.98day(-1) and 0.01-0.07day(-1), respectively. The dispersant Corexit enhanced degradation of n-alkanes but not of PAHs. Compared to biodegradation, photooxidation increased transformation of 4-5 ring PAHs by 70% and 3-4 ring alkylated PAHs by 36%. For the first time we observed that sunlight inhibited biodegradation of pristane and phytane, possibly due to inhibition of the bacteria that can degrade branched-alkanes. This study provides quantitative measures of oil degradation under relevant field conditions crucial for understanding and modeling the fate of spilled oil in the northern Gulf of Mexico. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Chemical and physical transformations of organic aerosol from the photo-oxidation of open biomass burning emissions in an environmental chamber (United States)

    C. J. Hennigan; M. A. Miracolo; G. J. Engelhart; A. A. May; A. A. Presto; T. Lee; A. P. Sullivan; G. R. McMeeking; H. Coe; C. E. Wold; W.-M. Hao; J. B. Gilman; W. C. Kuster; J. de Gouw; B. A. Schichtel; J. L. Collett; S. M. Kreidenweis; A. L. Robinson


    Smog chamber experiments were conducted to investigate the chemical and physical transformations of organic aerosol (OA) during photo-oxidation of open biomass burning emissions. The experiments were carried out at the US Forest Service Fire Science Laboratory as part of the third Fire Lab at Missoula Experiment (FLAME III). We investigated emissions from 12 different...

  19. Secondary organic aerosol formation from photo-oxidation of toluene with NOx and SO2: Chamber simulation with purified air versus urban ambient air as matrix (United States)

    Deng, Wei; Liu, Tengyu; Zhang, Yanli; Situ, Shuping; Hu, Qihou; He, Quanfu; Zhang, Zhou; Lü, Sujun; Bi, Xinhui; Wang, Xuemei; Boreave, Antoinette; George, Christian; Ding, Xiang; Wang, Xinming


    Chamber studies on the formation of secondary aerosols are mostly performed with purified air as matrix, it is of wide concern in what extent they might be different from the situations in ambient air, where a variety of gaseous and particulate components preexist. Here we compared the photo-oxidation of "toluene + NOx + SO2" combinations in a smog chamber in real urban ambient air matrix with that in purified air matrix. The secondary organic aerosols (SOA) mass concentrations and yields from toluene in the ambient air matrix, after subtracted ambient air background primary and secondary organic aerosols, were 9.0-34.0 and 5.6-12.9 times, respectively, greater than those in purified air matrix. Both homogeneous and heterogeneous oxidation of SO2 were enhanced in ambient air matrix experiments with observed 2.0-7.5 times higher SO2 degradation rates and 2.6-6.8 times faster sulfate formation than that in purified air matrix, resulting in higher in-situ particle acidity and consequently promoting acid-catalyzed SOA formation. In the ambient air experiments although averaged OH radical levels were elevated probably due to heterogeneous formation of OH on particle surface and/or ozonolysis of alkenes, non-OH oxidation pathways of SO2 became even more dominating. Under the same organic aerosol mass concentration, the SOA yields of toluene in purified air matrix experiments matched very well with the two-product model curve by Ng et al. (2007), yet the yields in ambient air on average was over two times larger. The results however were much near the best fit curve by Hildebrandt et al. (2009) with the volatility basis set (VBS) approach.

  20. The photobleaching of the free and encapsulated metallic phthalocyanine and its effect on the photooxidation of simple molecules. (United States)

    Fanchiotti, Brenda Gomes; Machado, Marcella Piffer Zamprogno; de Paula, Letícia Camilato; Durmuş, Mahmut; Nyokong, Tebello; da Silva Gonçalves, Arlan; da Silva, André Romero


    The photobleaching of an unsubstituted phthalocyanine (gallium(III) phthalocyanine chloride (GaPc)) and a substituted phthalocyanine (1,4-(tetrakis[4-(benzyloxy)phenoxy]phthalocyaninato) indium(III) chloride (InTBPPc)) was monitored for the free photosensitizers and for the phthalocyanines encapsulated into nanoparticles of PEGylated poly(D,L-lactide-co-glycolide) (PLGA-PEG). Phosphate-buffered solutions (PBS) and organic solutions of the free GaPc or the free InTBPPc, and suspensions of each encapsulated photosensitizer (2-15μmol/L) were irradiated using a laser diode of 665nm with a power of 1-104mW and a light dose of 7.5J/cm(2). The relative absorbance (RA) of the free GaPc dissolved in 1-methyl-2-pyrrolidone (MP) decreased 8.4 times when the laser power increased from 1mW to 104mW. However, the free or encapsulated GaPc did not suffer the photobleaching in PBS solution. The RA values decreased 2.4 times and 22.2 times for the free InTBPPc dissolved in PBS solution and in dimethylformamide (DMF), respectively, but the encapsulated InTBPPc was only photobleached when the laser power was 104mW at 8μmol/L. The increase of the free GaPc concentration favored the photobleaching in MP until 8μmol/L while the increase from 2μmol/L to 5μmol/L reduced the photodegradation in PBS solution. However, the photobleaching of the free InTBPPc in DMF or in PBS solution, and of each encapsulated photosensitizer was not influenced by increasing the concentration. The influence of the photobleaching on the capability of the free and encapsulated GaPc and InTBPPc to photooxidate the simple molecules was investigated monitoring the fluorescence of dimethylanthracene (DMA) and the tryptophan (Trp). Free InTBPPc was 2.0 and 1.8 times faster to photooxidate the DMA and Trp than it was the free GaPc, but the encapsulated GaPc was 3.4 times more efficient to photooxidize the Trp than it was the encapsulated InTBPPc due to the photodegradation suffered by the encapsulated In

  1. Integral parametrization of the Kinetics of Crosslink production in plasmid DNA as a function of 8-methoxypsoralen concentration

    Energy Technology Data Exchange (ETDEWEB)

    Vidania, R. de; Paramio, J. M.; Bauluz, C.


    In this paper we present results of crosslink production in pBR322 DNA along a wide range of 8-methoxypsoralen (8-MOP) concentration. Experimental data were obtained as DNA renaturation percentages, from the shift in hyperchromicity after a temperature-dependent denaturation-renaturation process. the experimental results showed a three-stage profile when represented as a function of the natural logarithms of 8-MOP concentration. an integral parametrization which allows a simultaneous fit of the three observed stages is presented here. the theoretical values of crosslink production determined from the fit are useful to asses the genotoxicity of psoralen-induced crosslinks in plasmid DNA. (Author) 24 refs.

  2. Synchrotron-based FTIR microspectroscopy for the mapping of photo-oxidation and additives in acrylonitrile-butadiene-styrene model samples and historical objects. (United States)

    Saviello, Daniela; Pouyet, Emeline; Toniolo, Lucia; Cotte, Marine; Nevin, Austin


    Synchrotron-based Fourier transform infrared micro-spectroscopy (SR-μFTIR) was used to map photo-oxidative degradation of acrylonitrile-butadiene-styrene (ABS) and to investigate the presence and the migration of additives in historical samples from important Italian design objects. High resolution (3×3 μm(2)) molecular maps were obtained by FTIR microspectroscopy in transmission mode, using a new method for the preparation of polymer thin sections. The depth of photo-oxidation in samples was evaluated and accompanied by the formation of ketones, aldehydes, esters, and unsaturated carbonyl compounds. This study demonstrates selective surface oxidation and a probable passivation of material against further degradation. In polymer fragments from design objects made of ABS from the 1960s, UV-stabilizers were detected and mapped, and microscopic inclusions of proteinaceous material were identified and mapped for the first time. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Sex-related differences in photoinhibition, photo-oxidative stress and photoprotection in stinging nettle (Urtica dioica L.) exposed to drought and nutrient deficiency. (United States)

    Simancas, Bárbara; Juvany, Marta; Cotado, Alba; Munné-Bosch, Sergi


    Dimorphic plant species can show distinct nutrient needs due to sex-related differences in nutrient allocation to reproductive structures, which can potentially affect their sensitivity to photoinhibition and photo-oxidative stress. Here, we investigated sex-related differences in the extent of photo-oxidative stress in male and female individuals of U. dioica exposed to a combination of severe drought and nutrient starvation. Male and female individuals of U. dioica subject to severe drought stress were exposed to various levels of nutrient availability. First, a set of plants grown under field conditions and exposed to summer drought was used to test the effects of nutrient supply (given as NPK fertilizer). Secondly, the effects of various phosphate concentrations in the nutrient solution were tested in drought-stressed potted plants. The Fv/Fm ratio (maximum efficiency of PSII photochemistry), photoprotection capacity (levels of carotenoids, including the xanthophyll cycle, and vitamins C and E), and the extent of lipid peroxidation (hydroperoxide levels) were measured. Results showed that an application of the NPK fertilizer to the soil had a positive effect on drought-stressed plants, reducing the extent of lipid peroxidation in both males and females. P deficiency led to residual photoinhibition, as indicated by significant reductions in the Fv/Fm ratio, and enhanced lipid peroxidation in females, but not in males. We conclude that (i) increased nutrient availability in the soil can alleviate photo-oxidative stress in drought-stressed U. dioica plants, and (ii) U. dioica plants show sexual secondary dimorphism in terms of photoinhibition and photo-oxidative stress, but this is only apparent when stress infringed on plants is very severe. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Efficient and stable photo-oxidation of water by a bismuth vanadate photoanode coupled with an iron oxyhydroxide oxygen evolution catalyst. (United States)

    Seabold, Jason A; Choi, Kyoung-Shin


    BiVO(4) films were prepared by a simple electrodeposition and annealing procedure and studied as oxygen evolving photoanodes for application in a water splitting photoelectrochemical cell. The resulting BiVO(4) electrodes maintained considerable photocurrent for photo-oxidation of sulfite, but generated significantly reduced photocurrent for photo-oxidation of water to oxygen, also decaying over time, suggesting that the photoelectrochemical performance of BiVO(4) for water oxidation is mainly limited by its poor catalytic ablity to oxidize water. In order to improve the water oxidation kinetics of the BiVO(4) electrode, a layer of FeOOH was placed on the BiVO(4) surface as an oxygen evolution catalyst using a new photodeposition route. The resulting BiVO(4)/FeOOH photoanode exhibitied significantly improved photocurrent and stability for photo-oxidation of water, which is one of the best among all oxide-based phoatoanode systems reported to date. In particular, the BiVO(4)/FeOOH photoanode showed an outstanding performance in the low bias region (i.e., E operating current density when assembling a complete p-n photoelectrochemical diode cell. The photocurrent-to-O(2) conversion efficiency of the BiVO(4)/FeOOH photoanode is ca. 96%, confirming that the photogenerated holes in the BiVO(4)/FeOOH photoanode are indeed excusively used for O(2) evolution. © 2012 American Chemical Society

  5. Influence of NH3 on secondary organic aerosols from the ozonolysis and photooxidation of α-pinene in a flow reactor (United States)

    Babar, Zaeem Bin; Park, Jun-Hyun; Lim, Ho-Jin


    This study presents detailed characterizations of a newly-developed flow reactor including (1) residence time distribution measurements, (2) relative humidity (RH) and temperature control, and (3) OH radical exposure range (i.e., atmospheric aging time). Hydroxyl (OH) radical exposures ranged from 8.20 × 1010 to 7.22 × 1011 molecules cm-3 s (0.5-4.9 d of atmospheric aging). In this study, the effects of NH3 gas on the secondary organic aerosol (SOA) formation of α-pinene by dark ozonolysis and photooxidation were investigated using the newly-developed flow reactor. For both dark α-pinene ozonolysis and photooxidation, higher SOA yields were observed in the presence of NH3 than in the absence of NH3. At RH of ∼50%, the SOA yield for ozonolysis and photooxidation in the presence of NH3 increased by 23% and 15% relative to those in the absence of NH3. Similar effects were observed at lower and higher RH conditions. Fourier transform infrared spectroscopy analysis confirmed the presence of nitrogen-containing functional groups in SOA formed in the presence of NH3. The α-pinene SOA formed in the presence of NH3 showed higher absorption and fluorescence for UV-visible radiation than those formed in the absence of NH3.

  6. A tridimensional view of the organization of actin filaments in the central nervous system by use of fluorescent photooxidation. (United States)

    Capani, Francisco; Saraceno, Ezequiel; Boti, Valeria Romina; Aon-Bertolino, Laura; Fernández, Juan Carlos; Gato, Fernándo; Kruse, Maria Sol; Krause, Maria Sol; Giraldez, Lisandro; Ellisman, Mark H; Coirini, Héctor


    Cellular and subcellular organization and distribution of actin filaments have been studied with various techniques. The use of fluorescence photo-oxidation combined with phalloidin conjugates with eosin has allowed the examination of the precise cellular and subcellular location of F-actin. Correlative fluorescence light microscopy and transmission electron microscopy studies of F-actin distribution are facilitated with this method for morphological and physiological studies. Because phalloidin-eosin is smaller than other markers, this method allows the analysis of the three-dimensional location of F-actin with high-resolution light microscopy, three-d serial sections reconstructions, and electron tomography. The combination of selective staining and three-dimensional reconstructions provide a valuable tool for revealing aspects of the synaptic morphology that are not available when conventional electron microscopy is used. By applying this selective staining technique and three-dimensional imaging, we uncovered the structural organization of actin in the postsynaptic densities in physiological and pathological conditions.

  7. Reactor model development: The removal performance of ferrous-catalysed photo-oxidation process by examining the reaction parameters

    Energy Technology Data Exchange (ETDEWEB)

    Chan, K.H. [Department of Civil and Structural Engineering, Research Centre for Environmental Technology and Management, Hong Kong Polytechnic University, Hunghom, Kowloon (Hong Kong); Chu, W., E-mail: [Department of Civil and Structural Engineering, Research Centre for Environmental Technology and Management, Hong Kong Polytechnic University, Hunghom, Kowloon (Hong Kong)


    The removal performance of the ferrous catalysed photo-oxidation process was investigated through the examination of major process parameters including pH levels and dosages of ferrous (Fe{sup 2+}) and hydrogen peroxide (H{sub 2}O{sub 2}). A common used herbicide, alachlor, was used as a target compound in the degradation process. In the study, alachlor was found to be effectively degraded by hydroxyl radicals (HO{center_dot}) which were generated by UV/Fe{sup 2+}/H{sub 2}O{sub 2} in the oxidation process. It was interesting to find that the pattern of reaction kinetics of alachlor varied depending on the initial concentrations of Fe{sup 2+} and H{sub 2}O{sub 2}. An optimum H{sub 2}O{sub 2} dosage was determined. This was practically useful because the overdose of H{sub 2}O{sub 2} would cause the process retardation. The conventional pseudo-first-order kinetics and two-stage first-order kinetics were observed at lower and higher Fe{sup 2+} concentrations, respectively. Models were proposed and used to stimulate the kinetic process. Thus, design charts were established for determining the reaction time (i.e., reactor sizing) required for predetermined removal performance of alachlor under different concentrations of H{sub 2}O{sub 2} and Fe{sup 2+}.

  8. Low-Density Polyethylene/Polyamide/Clay Blend Nanocomposites: Effect of Morphology of Clay on Their Photooxidation Resistance

    Directory of Open Access Journals (Sweden)

    N. Tz. Dintcheva


    Full Text Available The photooxidation behaviour of low-density polyethylene (LDPE/polyamide (PA blends, containing polyamide 11 (PA11 or polyamide 6 (PA6, has been investigated in the absence and presence of a small amount of commercial organomodified clay (OMMT. The polymer blends LDPE/PA11 and LDPE/PA6 at 75/25 wt./wt.%, with and without OMMT, have been prepared by a two-step procedure: extrusion and sheet formulation. The formulated complex systems have been subjected to accurate morphological analysis in order to evaluate the effect of the OMMT presence on the refinement of the blend morphology. Furthermore, the produced sheets have been subjected to arterial UVB exposure and the variations of the mechanical properties and chemical structure of all the investigated samples have been monitored as a function of the exposure time. Finally, the rate of the photodegradation of the complex systems has been related to the morphological changes of these systems upon OMMT addition.

  9. Characterization of products from the pyrolysis of rapeseed oil cake. (United States)

    Ucar, Suat; Ozkan, Ahmet R


    The main aim of this study was to investigate the composition of products from the pyrolysis of rapeseed oil cake in a fixed bed reactor at 400, 450, 500, 700 and 900 degrees C. The gas products mainly consisted of CO(2), CO, CH(4) and H(2)S at 500 degrees C. Empirical formula of bio-oil from the pyrolysis of rapeseed oil cake was CH(1.59)O(0.16)N(0.116)S(0.003) for 500 degrees C. Bio-oils mainly contained oleic acid, 1H-indole, 2,3,5-trimethoxy toluene, toluene, (Z)-9-octadecanamide, psoralene, phenol and phenol derivatives at all pyrolysis temperatures. Both non-aromatic and aromatic hydrocarbon compounds were determined in water phase of liquid product by Headspace-GC analysis. The heating values of bio-chars were found to be similar (24MJkg(-1)) at all pyrolysis temperatures.


    We have developed a process that uses surface corona for the production of ozone by passing air or oxygen through a high voltage electrical discharge and the emitted ultraviolet light is being used to activate a photocatalyst. A thin film of nanostructured TiO2 with primary part...

  11. Integrated continuous flow photoreactors: Photooxidation of (L)-methionine with singlet oxygen


    Emmanuel, Noémie; Mendoza Gallego, Carlos; Lismont, Marjorie; Dreesen, Laurent; Heinrichs, Benoît; Monbaliu, Jean-Christophe


    Development of photochemistry in macroscopic batch reaction vessels is hampered due to inherent limitations: light penetration remains superficial, resulting in inhomogeneous irradiation and hence to side-reactions or product degradation due to overexposure. The recent implementation of photochemical processes in microreactors under continuous-flow conditions appeared to be much more powerful than its batch analogue in terms of irradiation efficiency and light penetration. Furthermore, the fi...

  12. Integrated continuous flow photoreactors: Photooxidation of (L)-methionine with singlet oxygen


    Emmanuel, Noémie; Monbaliu, Jean-Christophe


    Development of photochemistry in macroscopic batch reaction vessels is hampered due to inherent limitations: light penetration remains superficial, resulting in inhomogeneous irradiation and hence to side-reactions or product degradation due to overexposure. The recent implementation of photochemical processes in microreactors under continuous-flow conditions appeared to be much more powerful than its batch analogue in terms of irradiation efficiency and light penetration. Furthermore, the fi...

  13. Integrated continuous flow photoreactors: Photooxidation of (L)-methionine derivatives with singlet oxygen


    Emmanuel, Noémie; Monbaliu, Jean-Christophe


    Development of photochemistry in macroscopic batch reaction vessels is hampered due to inherent limitations: light penetration remains superficial, resulting in inhomogeneous irradiation and hence to side-reactions or product degradation due to overexposure. The recent implementation of photochemical processes in microreactors under continuous-flow conditions appeared to be much more powerful than its batch analogue in terms of irradiation efficiency and light penetration. Furthermore, the fi...

  14. Photo-oxidation: Major sink of oxygen in the ocean surface layer


    Gieskes, W.W.C.; Laane, R. W. P. M.; Ruardij, P.


    Evidence is presented that the oxygen demand associated with photochemical processes in the surface layer of oceans and seas worldwide is of the same order of magnitude as the amount of oxygen released by photosynthesis of the world's marine phytoplankton. Both estimates are of necessity quite rough and therefore the agreement between oxygen loss and production, earlier found only locally in the Atlantic Ocean and the North Sea, came as a surprise. The heavy photochemical oxygen demand of the...

  15. Investigation of the β-pinene photooxidation by OH in the atmosphere simulation chamber SAPHIR (United States)

    Kaminski, Martin; Fuchs, Hendrik; Acir, Ismail-Hakki; Bohn, Birger; Brauers, Theo; Dorn, Hans-Peter; Häseler, Rolf; Hofzumahaus, Andreas; Li, Xin; Lutz, Anna; Nehr, Sascha; Rohrer, Franz; Tillmann, Ralf; Vereecken, Luc; Wegener, Robert; Wahner, Andreas


    Besides isoprene, monoterpenes are the non-methane volatile organic compounds (VOCs) with the highest global emission rates. Due to their high reactivity towards OH, monoterpenes can dominate the radical chemistry of the atmosphere in forested areas. In the present study the photochemical degradation mechanism of β-pinene was investigated in the Jülich atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber). One focus of this study is on the OH budget in the degradation process. Therefore, the SAPHIR chamber was equipped with instrumentation to measure radicals (OH, HO2, RO2), the total OH reactivity, important OH precursors (O3, HONO, HCHO), the parent VOC β-pinene, its main oxidation products, acetone and nopinone and photolysis frequencies. All experiments were carried out under low-NO conditions ( ≤ 300 ppt) and at atmospheric β-pinene concentrations ( ≤ 5 ppb) with and without addition of ozone. For the investigation of the OH budget, the OH production and destruction rates were calculated from measured quantities. Within the limits of accuracy of the instruments, the OH budget was balanced in all β-pinene oxidation experiments. However, even though the OH budget was closed, simulation results from the Master Chemical Mechanism (MCM) 3.2 showed that the OH production and destruction rates were underestimated by the model. The measured OH and HO2 concentrations were underestimated by up to a factor of 2, whereas the total OH reactivity was slightly overestimated because the model predicted a nopinone mixing ratio which was 3 times higher than measured. A new, theory-derived, first-generation product distribution by Vereecken and Peeters (2012) was able to reproduce the measured nopinone time series and the total OH reactivity. Nevertheless, the measured OH and HO2 concentrations remained underestimated by the numerical simulations. These observations together with the fact that the measured OH budget

  16. Molecular characterisation of secondary organic aerosol formed during cloud condensation-evaporation cycles from isoprene and methacrolein photooxidation (CUMULUS project) (United States)

    Giorio, C.; Monod, A.; Bregonzio-Rozier, L.; Siekmann, F.; Cazaunau, M.; Termine-Roussel, B.; DeWitt, H. L.; Gratien, A.; Michoud, V.; Pangui, E.; Ravier, S.; Tapparo, A.; Vermeylen, R.; Claeys, M.; Voisin, D.; Salque-Moreton, G.; Kalberer, M.; Doussin, J. F.


    Biogenic volatile organic compounds (BVOCs) undergo many reactions in the atmosphere and form a wide range of oxidised and water-soluble compounds. These compounds could partition into atmospheric water droplets, and react within the aqueous phase producing higher molecular weight and less volatile compounds which could remain in the particle phase after water evaporation (Ervens et al., 2011). The aim of this work is the characterisation of secondary organic aerosol (SOA) formed from the photooxidation of isoprene and methacrolein. The experiments were performed within the CUMULUS project (CloUd MULtiphase chemistry of organic compoUndS in the troposphere), at the 4.2 m3stainless steel CESAM chamber at LISA (Brégonzio-Rozier et al., 2016). In each experiment, isoprene or methacrolein was photooxidised with HONO and clouds have been produced to study oxidation processes in a multiphase (gas-particles-clouds) environment. Particular attention has been focused on SOA formation and aging during cloud condensation-evaporation cycles and a range of different on-line and off-line mass spectrometry techniques have been used to obtain a detailed characterisation of SOA at molecular level in dry conditions, during cloud events and after cloud evaporation. We observed a large number of long homologous series of oligomers in all experiments, together with a complex co-oligomerised system made of monomers with a large variety of different structures. Comparison of SOA from multiphasic (smog chamber) experiments and samples from aqueous phase oxidation of methacrolein with ·OH radical pointed out different types of oligomerisation reactions dominating the two different systems. Ervens et al. (2011) Atmos. Chem. Phys. 11, 11069-11102. Brégonzio-Rozier et al. (2016) Atmos. Chem. Phys. 16, 1747-1760.

  17. Perturbation of pharmacologically relevant polyphenolic compounds in Moringa oleifera against photo-oxidative damages imposed by gamma radiation. (United States)

    Ramabulana, T; Mavunda, R D; Steenkamp, P A; Piater, L A; Dubery, I A; Madala, N E


    Oxidative stress is a physiological state associated with almost all biotic and abiotic stresses in plants. This phenomenon occurs due to imbalances which result from the overproduction of reactive oxygen species (ROS). Plants, however, have developed sophisticated mechanisms to mitigate the effect of ROS. In this regard, plant polyphenolic metabolites such as flavonoids are known to possess high antioxidant activities. In the current study, changes in the levels of phenolic compounds from Moringa oleifera after gamma radiation treatment were investigated with reverse phase liquid chromatography and mass spectrometric techniques in combination with multivariate data models such as principal component analysis and orthogonal projection to latent structures discriminant analysis. Our results revealed several polyphenolic compounds such as hydroxycinnamoyl derivatives and flavonoid molecules to be down-regulated post-radiation treatment. Interestingly, other flavonoid molecules were found to be up-regulated post-radiation treatment, thereby suggesting a possible compensatory phenomenon. The existence and involvement of structurally similar metabolites (such as regio-isomers of chlorogenic acids) in M. oleifera towards mitigating photo-oxidative damages are in support of the proposed evolutionary existence of a large pool of polyphenolics which contribute to the state of readiness, aptly described as a "better safe than sorry" phenomenon. Our study thus reaffirms the involvement of phenolic compounds as a first line of constitutive/preformed protection against oxidative stress. Furthermore, the obtained data supports M. oleifera as a source of versatile and pharmacologically relevant metabolites that may be exploited for ameliorating the oxidative damages imposed by several metabolic disorders in humans. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. In-cloud multiphase behaviour of acetone in the troposphere: gas uptake, Henry's law equilibrium and aqueous phase photooxidation. (United States)

    Poulain, Laurent; Katrib, Yasmine; Isikli, Estelle; Liu, Yao; Wortham, Henri; Mirabel, Philippe; Le Calvé, Stéphane; Monod, Anne


    Acetone is ubiquitous in the troposphere. Several papers have focused in the past on its gas phase reactivity and its impact on tropospheric chemistry. However, acetone is also present in atmospheric water droplets where its behaviour is still relatively unknown. In this work, we present its gas/aqueous phase transfer and its aqueous phase photooxidation. The uptake coefficient of acetone on water droplets was measured between 268 and 281K (γ=0.7 x 10(-2)-1.4 x 10(-2)), using the droplet train technique coupled to a mass spectrometer. The mass accommodation coefficient α (derived from γ) was found in the range (1.0-3.0±0.25) x 10(-2). Henry's law constant of acetone was directly measured between 283 and 298K using a dynamic equilibrium system (H((298K))=(29±5)Matm(-1)), with the Van't Hoff expression lnH(T)=(5100±1100)/T-(13.4±3.9). A recommended value of H was suggested according to comparison with literature. The OH-oxidation of acetone in the aqueous phase was carried out at 298K, under two different pH conditions: at pH=2, and under unbuffered conditions. In both cases, the formation of methylglyoxal, formaldehyde, hydroxyacetone, acetic acid/acetate and formic acid/formate was observed. The formation of small amounts of four hydroperoxides was also detected, and one of them was identified as peroxyacetic acid. A drastic effect of pH was observed on the yields of formaldehyde, one hydroperoxide, and, (to a lesser extent) acetic acid/acetate. Based on the experimental observations, a chemical mechanism of OH-oxidation of acetone in the aqueous phase was proposed and discussed. Atmospheric implications of these findings were finally discussed. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. Assessing the role of solar radiation in heating, photosynthesis, and photo-oxidation in upper Arctic Ocean waters via autonomous buoys (United States)

    Hill, V. J.; Steele, M.; Light, B.


    As part of the Arctic Observing Network, a new ice-tethered buoy has been developed for monitoring the role of sunlight in regulating ocean temperature, phytoplankton growth, and carbon cycling. A 20 or 50 m string (depending on local bathymetry) supports sensors both within and below the ice for the hourly measurement of downwelling irradiance, temperature, Chlorophyll a, light backscattering, and dissolved organic material (DOM). Two buoys were deployed in March 2014 and two in March 2015. Because the buoys are engineered to survive melting out of first year ice, they have successfully provided complete seasonal records of water column warming, phytoplankton abundance and photo-oxidation patterns in the Pacific Arctic Region. The data collected will be used to determine whether reduced ice extent and thinner ice are driving increases in under ice warming, accelerating bottom ice ablation, increasing available photosynthetic radiation to support large under ice blooms, and to quantify photo-oxidation of the DOM pool. Observations so far have revealed strong under ice daily warming as high as ±0.5 °C driven by local solar radiation. Water column absorption was dominated by colored dissolved organic material which served to trap solar radiation in the upper water column. Chlorophyll concentrations observed in June and July indicated high phytoplankton abundance beneath the ice. Light intensity at this time was not sufficient to support growth rates high enough to produce the 8 to 10 mg m-3 of chlorophyll observed. We hypothesize that phytoplankton were advected under the ice from the ice edge. However, once there phytoplankton were able to sustain low growth rates leading to nutrient limitation before open water status was reached. Strong daily cycles of photo-oxidation have also been observed in the late summer that indicate the fast cycling of highly labile DOM in the open waters of the Pacific Arctic Region.

  20. Inosine Can Increase DNA's Susceptibility to Photo-oxidation by a RuII Complex due to Structural Change in the Minor Groove. (United States)

    Keane, Páraic M; Hall, James P; Poynton, Fergus E; Poulsen, Bjørn C; Gurung, Sarah P; Clark, Ian P; Sazanovich, Igor V; Towrie, Michael; Gunnlaugsson, Thorfinnur; Quinn, Susan J; Cardin, Christine J; Kelly, John M


    Key to the development of DNA-targeting phototherapeutic drugs is determining the interplay between the photoactivity of the drug and its binding preference for a target sequence. For the photo-oxidising lambda-[Ru(TAP)2 (dppz)]2+ (Λ-1) (dppz=dipyridophenazine) complex bound to either d{T1 C2 G3 G4 C5 G6 C7 C8 G9 A10 }2 (G9) or d{TCGGCGCCIA}2 (I9), the X-ray crystal structures show the dppz intercalated at the terminal T1 C2 ;G9 A10 step or T1 C2 ;I9 A10 step. Thus substitution of the G9 nucleobase by inosine does not affect intercalation in the solid state although with I9 the dppz is more deeply inserted. In solution it is found that the extent of guanine photo-oxidation, and the rate of back electron-transfer, as determined by pico- and nanosecond time-resolved infrared and transient visible absorption spectroscopy, is enhanced in I9, despite it containing the less oxidisable inosine. This is attributed to the nature of the binding in the minor groove due to the absence of an NH2 group. Similar behaviour and the same binding site in the crystal are found for d{TTGGCGCCAA}2 (A9). In solution, we propose that intercalation occurs at the C2 G3 ;C8 I9 or T2 G3 ;C8 A9 steps, respectively, with G3 the likely target for photo-oxidation. This demonstrates how changes in the minor groove (in this case removal of an NH2 group) can facilitate binding of RuII dppz complexes and hence influence any sensitised reactions occurring at these sites. No similar enhancement of photooxidation on binding to I9 is found for the delta enantiomer. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Understanding the impact of recent advances in isoprene photooxidation on simulations of regional air quality

    Directory of Open Access Journals (Sweden)

    Y. Xie


    Full Text Available The CMAQ (Community Multiscale Air Quality us model in combination with observations for INTEX-NA/ICARTT (Intercontinental Chemical Transport Experiment–North America/International Consortium for Atmospheric Research on Transport and Transformation 2004 are used to evaluate recent advances in isoprene oxidation chemistry and provide constraints on isoprene nitrate yields, isoprene nitrate lifetimes, and NOx recycling rates. We incorporate recent advances in isoprene oxidation chemistry into the SAPRC-07 chemical mechanism within the US EPA (United States Environmental Protection Agency CMAQ model. The results show improved model performance for a range of species compared against aircraft observations from the INTEX-NA/ICARTT 2004 field campaign. We further investigate the key processes in isoprene nitrate chemistry and evaluate the impact of uncertainties in the isoprene nitrate yield, NOx (NOx = NO + NO2 recycling efficiency, dry deposition velocity, and RO2 + HO2 reaction rates. We focus our examination on the southeastern United States, which is impacted by both abundant isoprene emissions and high levels of anthropogenic pollutants. We find that NOx concentrations increase by 4–9% as a result of reduced removal by isoprene nitrate chemistry. O3 increases by 2 ppbv as a result of changes in NOx. OH concentrations increase by 30%, which can be primarily attributed to greater HOx production. We find that the model can capture observed total alkyl and multifunctional nitrates (∑ANs and their relationship with O3 by assuming either an isoprene nitrate yield of 6% and daytime lifetime of 6 hours or a yield of 12% and lifetime of 4 h. Uncertainties in the isoprene nitrates can impact ozone production by 10% and OH concentrations by 6%. The uncertainties in NOx recycling efficiency appear to have larger effects than uncertainties in isoprene nitrate yield and dry deposition velocity. Further progress depends on improved understanding of

  2. Measurement of photooxidants relevant to human biometeorology in an urban agglomeration (PHOTOX). Measurement of various hydrocarbons as precursors of photooxidants relevant to human biometeorology (KOVOX). Final report of Part 2; Erfassung von human-biometeorologisch relevanten Photooxidantien in einem Ballungsraum (PHOTOX). Erfassung verschiedener Kohlenwasserstoffe als Vorlaeufersubstanzen fuer human-biometeorologisch relevante Photooxidantien (KOVOX). Abschlussbericht zum Teil 2

    Energy Technology Data Exchange (ETDEWEB)

    Jakobi, G.; Fabian, P. [eds.


    The air-chemical components ozone and PAN (peroxy acetyl nitrate), their precursors NO and NO{sub 2} and the meteorological parameters air temperature, humidity, global radiation, wind direction and wind velocity were measured in the framework of a research project (PHOTOX - Measurement of photooxidants relevant to human biometeorology in an urban agglomeration) carried out by the Department of Bioclimatology and Pollution Research. Further, a wide range of anthropogenic and biogenic hydrocarbons, which are important groups of precursors of photooxidants and potential pollution factors, were measured in the framework of another research project (KOVOX - Measurement of various hydrocarbons as precursors of photooxidants relevant to human biometeorology). (orig/SR) [Deutsch] Die Messung der luftchemischen Komponenten Ozon und PAN (Peroxiacetylnitrat), deren Vorlaeufersubstanzen Stickstoffmonoxid (NO) und Stickstoffdioxid (NO{sub 2}) sowie deren meteorologischen Parameter Lufttemperatur, Luftfeuchtigkeit, Globalstrahlung, Windrichtung und Windgeschwindigkeit wurde im Rahmen des am Lehrstuhl fuer Bioklimatologie und Immisionsforschung laufenden Forschungsvorhabens ``Erfassung von human-biometeorologisch relevanten Photooxidantien in einem Ballungsraum (PHOTOX)`` durchgefuehrt. Des weiteren erfolgte die Messung einer breiten Palette anthropogener und biogener Kohlenwasserstoffe als wichtige Gruppen der Vorlaeufersubstanzen zur Photooxidantienbildung und moeglicher Wirkfaktoren, im Rahmen des Projektes ``Erfassung verschiedener Kohlenwasserstoffe als Vorlaeufersubstanzen fuer human-biometeorologisch relevante Photooxidantien (KOVOX)``. (orig./BW)

  3. Lutein and zeaxanthin supplementation reduces photo-oxidative damage and modulates the expression of inflammation-related genes in retinal pigment epithelial cells (United States)

    Bian, Qingning; Gao, Shasha; Zhou, Jilin; Qin, Jian; Taylor, Allen; Johnson, Elizabeth J.; Tang, Guangwen; Sparrow, Janet R.; Gierhart, Dennis; Shang, Fu


    Oxidative damage and inflammation are related to the pathogenesis of age-related macular degeneration (AMD). Epidemiologic studies suggest that insufficient dietary lutein and zeaxanthin intake or lower serum zeaxanthin levels are associated with increased risk for AMD. The objective of this work is to test the protective effects of lutein and zeaxanthin against photo-oxidative damage to retinal pigment epithelial cells (RPE) and oxidation-induced changes in expression of inflammation-related genes. To mimic lipofuscin-mediated photo-oxidation in vivo, we used ARPE-19 cells that accumulated A2E, a lipofuscin fluorophore and photosensitizer, as a model system to investigate the effects of lutein and zeaxanthin supplementation. The data show that supplementation with lutein or zeaxanthin in the medium resulted in accumulation of lutein or zeaxanthin in the RPE cells. The concentrations of lutein and zeaxanthin in the cells were 2–14-fold of that detected in the medium, indicating that ARPE-19 cells actively take up lutein or zeaxanthin. As compared with untreated cells, exposure of A2E-containing RPE to blue light resulted in a 40–60% decrease in proteasome activity, a 50–80% decrease in expression of CFH and MCP-1, and an ~ 20-fold increase in expression of IL-8. The photo-oxidation-induced changes in expression of MCP-1, IL-8 and CFH were similar to those caused by chemical inhibition of the proteasome, suggesting that inactivation of the proteasome is involved in the photo-oxidation-induced alteration in expression of these inflammation-related genes. Incubation of the A2E-containing RPE with lutein or zeaxanthin prior to blue light exposure significantly attenuated the photo-oxidation-induced inactivation of the proteasome and photo-oxidation induced changes in expression of MCP-1, IL-8, and CFH. Together, these data indicate that lutein or zeaxanthin modulates inflammatory responses in cultured RPE in response to photo-oxidation. Protecting the proteasome

  4. Photooxidation of the phenylazonaphthol AO20 on TIO2: kinetic and mechanistic investigations. (United States)

    Galindo, C; Jacques, P; Kalt, A


    The results of the photocatalytic and photosensitized degradations of the monoazo dye AO20 in aqueous solution using suspended titanium dioxide are presented. Kinetic and mechanistic details have been elucidated using UV/Vis, FTIR and TCO techniques. It was proven that adsorption of dye molecules onto the support material is essential for the processes to be effective. Moreover, even if their mechanisms differ during the early stages, photocatalysis and photosensitization lead to very similar ultimate breakdown products. Indeed, the original dye anchored to the oxide surface systematically undergoes fast decomposition until it is transformed into CO2 or aliphatic acids (formic, acetic, oxalic acids), which react rather slowly with hydroxyl radicals or trapped holes.

  5. Photooxidation of Isopropanol and Acetone Using TiO(sub 2) Suspension and UV Light

    Energy Technology Data Exchange (ETDEWEB)

    El-Morsi, Taha; Nanny, Mark A.


    Small polar organic compounds such as alcohols, ketones and aldehydes are highly soluble and do not adsorb strongly to the TiO2 surface and, therefore, may be fairly resistant to photocatalytic degradation. Photodegradation of an aqueous solution of isopropanol and its resulting photodegradation product acetone was investigated as a function of TiO2 substrate concentrations and solution ionic strength and pH. In the presence of 2g/L TiO2, isopropanol completely disappeared within 3 hrs, resulting in the nearly complete transformation into acetone. Subsequent photodegradation of acetone occurred at a much slower rate and resulted in complete mineralization. Increasing the pH slightly decreased the photodegradation rate. Conversely, the degradation rate was enhanced slightly by increasing the ionic strength. The presence of tetranitromethane decreased the isopropanol degradation significantly. This result, combined with the minimal degree of adsorption of isopropanol and acetone onto the surface of the photocatalyst, suggests that the photodegradation pathway occurs via free OH radicals in bulk solution rather than on the catalyst surface.

  6. Systemic and Intracellular Responses to Photooxidative Stress in Arabidopsis[W (United States)

    Rossel, Jan Bart; Wilson, Pip B.; Hussain, Dawar; Woo, Nick S.; Gordon, Matthew J.; Mewett, Osman P.; Howell, Katharine A.; Whelan, Jim; Kazan, Kemal; Pogson, Barry J.


    As the sun tracks daily through the sky from east to west, different parts of the canopy are exposed to high light (HL). The extent of and mechanisms by which a systemic acquired acclimation (SAA) response might preacclimate shaded leaves that will be subsequently exposed to full sunlight is largely undefined. We investigated the role of an Arabidopsis thaliana zinc finger transcription factor, ZAT10, in SAA. ZAT10 overexpression resulted in enhanced tolerance to photoinhibitory light and exogenous H2O2, increased expression of antioxidative genes whose products are targeted to multiple subcellular compartments. Partial HL exposure of a leaf or leaves rapidly induced ZAT10 mRNA in distal, shaded photosynthetic tissues, including the floral stem, cauline leaves, and rosette, but not in roots. Fully 86% of fivefold HL-upregulated and 71% of HL-downregulated genes were induced and repressed, respectively, in distal, shaded leaves. Between 15 and 23% of genes whose expression changed in the HL and/or distal tissues were coexpressed in the ZAT10 overexpression plants, implicating ZAT10 in modulating the expression of SAA-regulated genes. The SAA response was detectable in plants with mutations in abscisic acid, methyl jasmonate, or salicylic acid synthesis or perception, and systemic H2O2 diffusion was not detected. Hence, SAA is distinct from pathogen-stimulated systemic acquired resistance and apparently involves a novel signal or combination of signals that preacclimate photosynthetic tissues to HL. PMID:18156220

  7. Wavelength-dependent photooxidation and photoreduction of protochlorophyllide and protochlorophyll in the innermost leaves of cabbage (Brassica oleracea var. capitata L.). (United States)

    Erdei, Anna Laura; Kósa, Annamária; Kovács-Smirová, Lilla; Böddi, Béla


    The photoreduction and photooxidation processes of different protochlorophyll(ide) forms were studied in the innermost leaves of cabbage (Brassica oleracea var. capitata L.) under monochromatic irradiations. Room-temperature fluorescence emission spectra were measured from the same leaf spots before and after illumination to follow the wavelength dependence of the photochemical reactions. Short-wavelength light of 7 µmol photons m(-2) s(-1) (625-630 nm) provoked mainly bleaching, and longer wavelengths (630-640 nm) caused both bleaching and photoreduction, while above 640 nm resulted in basically photoreduction. When bleached leaves were kept in darkness at room temperature, all protochlorophyll(ide) forms regenerated during 72 h. Oxygen-reduced environment decreased the extent of bleaching suggesting the involvement of reactive oxygen species. These results confirm that the short-wavelength, 628 nm absorbing, and 633 nm emitting protochlorophyll(ide) form in etiolated cabbage leaves sensibilizes photooxidation. However, the 628 nm light at low intensities stimulates the photoreduction of the longer wavelength protochlorophyllide forms. Kinetic measurements showed that photoreduction saturates at a low PFD (photon flux density) compared to bleaching, suggesting that the quantum yield of photoreduction is higher than that of bleaching.

  8. Design and study of Bi[1,8]naphthyridine ligands as potential photooxidation mediators in Ru(II) polypyridyl aquo complexes. (United States)

    Zong, Ruifa; Naud, Frederic; Segal, Carrie; Burke, John; Wu, Feiyue; Thummel, Randolph


    A series of 3,3'-polymethylene-bridged bi[1,8]naphthyridine (binap) ligands, 3a-c, are complexed with Ru(II) to afford [Ru(tpy)(3a-c)(H(2)O)](2+) where an uncomplexed nitrogen on 3a-c is situated so it can form a H-bond with the coordinated water. An additional complex involving [Ru(4'-NMe(2)tpy)(3b)(H(2)O)](2+) is also prepared. X-ray analyses of the [Ru(tpy)(3a,c)(H(2)O)](2+) complexes indicate well-organized H-bonds even when the binap is nonplanar. In an attempt to realize photooxidation, the effects of light, varying potential, and pH were examined. A Pourbaix diagram indicated that the oxidation potential decreased by approximately 0.5 V in the pH range of 1.9-11.6. The lowest-energy electronic absorption for the binap complexes involves the metal-to-ligand charge transfer to the binap ligand and is sensitive to ligand planarity. The absorbance shifted to a lower energy as the auxiliary ligand became a better donor (4'-NMe(2)tpy) or as the water was deprotonated. Acetonitrile was found to displace water most easily for the complex of 3c, where the ligand is the least planar. Despite promising features, photooxidation of the bound water was not observed.

  9. TiO2anatase nanorods with non-equilibrium crystallographic {001} facets and their coatings exhibiting high photo-oxidation of NO gas. (United States)

    Habran, Margarita; Krambrock, Klaus; Maia da Costa, M E H; Morgado, Edisson; Marinkovic, Bojan A


    Development of highly active photocatalysts is mandatory for more widespread application of this alternative environmental technology. Synthesis of photocatalysts, such as anatase TiO 2 , with more reactive, non-equilibrium, crystallographic facets is theoretically justified by a more efficient interfacial charge transfer to reactive adsorbed species, increasing quantum efficiency of photocatalyst. Air and vacuum calcinations of protonated trititanate nanotubes lead to their transformation to anatase nanorods. The nanorods synthesized by air calcination demonstrate photo-oxidation of NO gas more than three times superior to the one presented by the benchmark P-25 photocatalyst. This performance has been explained in terms of 50% higher specific surface area and, more importantly, through the predominance of more reactive, non-equilibrium, {001} crystallographic facets of the anatase nanorods. These facets present a high density of undercoordinated Ti cations, which favors adsorption of reactant species, and strained Ti-O-Ti bonds, leading to more efficient photo-oxidation reactions. Reduced Ti species, such as Ti 3+ , were not observed in the as-obtained nanorods, while reactive adsorbed molecules are scarce on the nanorods obtained through vacuum calcination. Dip-coating of TiO 2 anatase nanorods (air calcined) over soda-lime glass plates was used to prepare visible light transparent, superhydrophilic and highly adherent photocatalytic coatings with homogenously distributed nanopores.

  10. Characterization of aerosol photooxidation flow reactors: heterogeneous oxidation, secondary organic aerosol formation and cloud condensation nuclei activity measurements

    Directory of Open Access Journals (Sweden)

    A. T. Lambe


    Full Text Available Motivated by the need to develop instrumental techniques for characterizing organic aerosol aging, we report on the performance of the Toronto Photo-Oxidation Tube (TPOT and Potential Aerosol Mass (PAM flow tube reactors under a variety of experimental conditions. The PAM system was designed with lower surface-area-to-volume (SA/V ratio to minimize wall effects; the TPOT reactor was designed to study heterogeneous aerosol chemistry where wall loss can be independently measured. The following studies were performed: (1 transmission efficiency measurements for CO2, SO2, and bis(2-ethylhexyl sebacate (BES particles, (2 H2SO4 yield measurements from the oxidation of SO2, (3 residence time distribution (RTD measurements for CO2, SO2, and BES particles, (4 aerosol mass spectra, O/C and H/C ratios, and cloud condensation nuclei (CCN activity measurements of BES particles exposed to OH radicals, and (5 aerosol mass spectra, O/C and H/C ratios, CCN activity, and yield measurements of secondary organic aerosol (SOA generated from gas-phase OH oxidation of m-xylene and α-pinene. OH exposures ranged from (2.0 ± 1.0 × 1010 to (1.8 ± 0.3 × 1012 molec cm−3 s. Where applicable, data from the flow tube reactors are compared with published results from the Caltech smog chamber. The TPOT yielded narrower RTDs. However, its transmission efficiency for SO2 was lower than that for the PAM. Transmission efficiency for BES and H2SO4 particles was size-dependent and was similar for the two flow tube designs. Oxidized BES particles had similar O/C and H/C ratios and CCN activity at OH exposures greater than 1011 molec cm−3 s, but different CCN activity at lower OH exposures. The O/C ratio, H/C ratio, and yield of m-xylene and α-pinene SOA was strongly affected by reactor design and

  11. Speciation analysis of organoarsenical compounds in biological matrices by coupling ion chromatography to atomic fluorescence spectrometry with on-line photooxidation and hydride generation

    Energy Technology Data Exchange (ETDEWEB)

    Simon, S.; Lobos, G.; Pannier, F.; De Gregori, I.; Pinochet, H.; Potin-gautier, M


    The optimisation of an on-line decomposition based on UV photooxidation for the analysis of organoarsenic species by coupling cation-exchange chromatography and atomic fluorescence spectrometry with hydride generation, is described. In this study, special consideration is given to the compatibility of mobile phases with post-column treatments. Results show that the most commonly used mobile phase, aqueous pyridine solutions, decreases species conversion efficiency, leading to a significant loss of sensitivity. New fully-compatible chromatographic conditions are proposed to separate arsenobetaine, arsenocholine, trimethylarsine oxide and tetramethylarsonium ion within 20 min. The very low absolute limits of detection, 4-12 pg(As), allow speciation at trace levels. Analysis of a certified reference fish tissue (DORM-2) and other seafood samples (French and Chilean oysters and mussel) highlights the robustness and the accuracy of the optimised system.

  12. Two-electron photo-oxidation of betanin on titanium dioxide and potential for improved dye-sensitized solar energy conversion (United States)

    Knorr, Fritz J.; Malamen, Deborah J.; McHale, Jeanne L.; Marchioro, Arianna; Moser, Jacques E.


    The plant pigment betanin is investigated as a dye-sensitizer on TiO2 with regard to its potential to undergo twoelectron oxidation following one-photon excitation. Electrochemical, spectroelectrochemical and transient absorption measurements provide evidence for two-electron proton-coupled photo-oxidation leading to a quinone methide intermediate which rearranges to 2-decarboxy-2,3-dehydrobetanin. Time-resolved spectroscopy measurements of betanin on nanocrystalline TiO2 and ZrO2 films were performed on femtosecond and nanosecond time-scales and provide evidence for transient species with absorption bands in the blue and the red. The results shed light on previous reports of high quantum efficiencies for electron injection and point the way to improved solar conversion efficiency of organic dyesensitized solar cells.

  13. Effects of NOx on the molecular composition of secondary organic aerosol formed by the ozonolysis and photooxidation of α-pinene (United States)

    Park, Jun-Hyun; Babar, Zaeem Bin; Baek, Sun Jong; Kim, Hyun Sik; Lim, Ho-Jin


    The molecular composition of secondary organic aerosol (SOA), obtained from the ozonolysis and photooxidation of α-pinene, was investigated using ultrahigh-resolution Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) in negative ion mode electrospray ionization (ESI). SOA formation was performed in an indoor smog chamber. The molecular formulae of individual species were identified on the basis of the measured ionic mass using guidelines, such as number of atoms, elemental ratios, and the nitrogen rule. In each of the SOAs obtained, 815-3501 monomeric and oligomeric (mainly dimeric) species were identified below m/z 800. From ozonolysis, mainly 95% of the typical oxygenated species (CHO) were detected, whereas from photooxidation under high NOx conditions, 32% of nitrogen-containing species (CHON) were detected. Several common intense species (e.g., C9H14O6, C10H14O6, C10H16O5, C17H26O7, C19H28O9, C10H15NO8, and C10H15NO9) could be listed as candidate tracers for the conventional tracers for α-pinene SOA. The increased percentage of CHON as a primary effect of NOx on the SOA composition evidently affected other physicochemical parameters, such as elemental ratios (i.e., O/C, H/C, and N/C), the double-bond equivalent (DBE), the carbon oxidation state (OSC), and the organic-mass-to-carbon ratio (OM/OC). The O/C and OM/OC for CHON were greater than those observed for CHO, indicating that nitrogen preferentially exists in the oxidized form (e.g., -ONO2). The complexity of oligomerization was observed in DBE and OM/OC according to the number of carbon atoms.

  14. Productivity

    DEFF Research Database (Denmark)

    Spring, Martin; Johnes, Geraint; Hald, Kim Sundtoft

    Productivity is increasingly critical for developed economies. It has always been important: as Paul Krugman puts it, “Productivity isn’t everything, but in the long run it is almost everything. A country’s ability to improve its standard of living over time depends almost entirely on its ability...... to raise its output per worker”(Krugman, 1994). Analyses of productivity have, by and large, been the preserve of economists. Operations Management (OM) is rooted in a similar concern for the efficient use of scarce resources; Management Accounting (MA) is concerned with the institutionalised measurement...... and management of productivity. Yet the three perspectives are rarely connected. This paper is a sketch of a literature review seeking to identify, contrast and reconcile these three perspectives. In so doing, it aims to strengthen the connections between policy and managerial analyses of productivity....

  15. production

    African Journals Online (AJOL)

    South African Society of Animal Production, Transkei,. 15-17 April, 1986. N.M. Tainton. Department of ... association with grazing and browsing animals, whilst of course its general degradation in recent years can be ... physiology, anatomy, histology, pathology and animal pro- ducts technology required by Animal Science ...

  16. Effect of nitrogen oxides (NO and NO2) and toluene on SO2 photooxidation, nucleation and growth: A smog chamber study (United States)

    Li, Kangwei; Chen, Linghong; White, Stephen J.; Han, Ke; Lv, Biao; Bao, Kaiji; Wu, Xuecheng; Gao, Xiang; Azzi, Merched; Cen, Kefa


    The formation and growth of new particles has recently been shown to have a significant influence on Chinese haze pollution, and sulfuric acid has long been recognized as a major contributor to new particle formation. In this study, four comparison groups of experiments related to SO2 photooxidation, as well as aerosol nucleation and growth, have been conducted in the CAPS-ZJU (Complex Air Pollution Study-Zhejiang University) smog chamber. These were conducted either under SO2/NOx or SO2/toluene gas-phase environments in the absence of seed particles. During aerosol nucleation and growth process, several physical properties such as mass, size and effective density were measured simultaneously by Scanning Mobility Particle Sizer (SMPS) and Differential Mobility Analyzer-Aerosol Particle Mass Analyzer-Condensation Particle Counter (DMA-APM-CPC). The effective density of new particles decreased from 1.8 to 1.35 g/cm3 as the particle size increased from 20 to 65 nm. The single particle mass showed good power-law relationship with mobility diameter, with an average mass-mobility exponent of 2.885. A new algorithm and a reference density of 1.38 g/cm3 based on size-resolved single particle mass (SPM) were proposed to calculate the mass concentration of new particles. Two methods based on Log Normal and Max Concentration were applied to derive particle growth rate (GR), and data merging from both methods was implemented to decrease calculation uncertainty. Meanwhile, both continuous nucleation and inhibition of further growth in sub-20 nm size range were observed in different experiments depending on composition, and possible reasons were analyzed. The presence of NO was found to suppress nucleation and subsequent aerosol growth; while the presence of NO2 or toluene promoted it. It was concluded that decreasing NOx (NO or NO2) or increasing toluene may promote SO2 photooxidation, nucleation and subsequent aerosol growth, all of which is significant for deeper

  17. Development of an automatic system dedicated to the writing of explicit and reduced chemical schemes suited to the photo-oxidant pollution study at different scales; Developpement d'une chaine automatique d'ecriture de schemas chimiques explicites et reduits adaptes a l'etude de la pollution photooxydante aux differentes echelles

    Energy Technology Data Exchange (ETDEWEB)

    Laval-Szopa, S


    Millions of compounds are involved in atmospheric chemistry. Chemical schemes must then be reduced to model the photo-oxidant pollution using chemistry-transport models (CTM). Such reduced schemes describe the atmospheric VOC oxidation using typically a hundred of species. The reduction methods depend actually on the particular case under consideration. The recent emergence of multi-scale CTM sets the problem of the use of reduced chemical schemes developed for a specified scale to the simultaneous modeling of several space scales. The objective of this work was to develop and assess an automatic procedure allowing to write explicit and reduced chemical schemes suited to the study of photo-oxidant pollution at different scales. The method is based on (1) the development of a tool dedicated to the writing of explicit schemes for VOC oxidation and (2) the assessment of reduced schemes using the explicit scheme as a reference. In order to minimize the problems involved in the development of chemical schemes, an automatic generator of explicit chemical schemes was developed for the tropospheric VOC oxidation. This generator is based on state of the art in terms of reactivity and mechanisms. It allows the writing of the whole set of reactions implied in the oxidation of a given primary compound, from its initiation to its total oxidation in CO{sub 2} et H{sub 2}O. A reference chemical scheme was built, using the generator, for about seventy primary VOC, chosen to be representative of both anthropogenic and biogenic emissions. The scheme describes their oxidation through more than 2 millions of reactions and 350.000 species. Three methods were applied to reduce the size of the chemical scheme: (i) use of operators, based on the redundancy of inorganic chemistry implied in the VOC oxidation, (ii) lumping of primary species having similar reactivities and (iii) lumping of secondary products into surrogate species. The number of species in the final reduced scheme is 150, i

  18. TiO{sub 2} assisted photo-oxidation of wastewater prior to voltammetric determination of trace metals: Eco-friendly alternative to traditional digestion methods

    Energy Technology Data Exchange (ETDEWEB)

    Lejbt, Beata; Ospina-Alvarez, Natalia; Miecznikowski, Krzysztof, E-mail:; Krasnodębska-Ostręga, Beata, E-mail:


    Highlights: • Cheap and eco-friendly method using anatase-assisted photodecomposition to pre-treat wastewater samples prior to trace metal analysis. • Addition of polyvinylidene fluoride did not affect the efficiency of organic matter decomposition. • TiO{sub 2} assisted photo-oxidation procedure is equally effective than ICP MS determination after UV assisted digestion with H{sub 2}O{sub 2} addition. - Abstract: Voltammetry is a sensitive method for metal determination and one alternative to ICP MS, but its limitation is the influence of the organic matrix on the measurements. To avoid those interferences, wet digestion with H{sub 2}O{sub 2} accelerated with UV irradiation is applied and evaporation of excess of reagents is required. In this study, photolytic oxidation in quartz tubes with anatase was carried out, using as object of study wastewater samples with high amount of organic matter. Cadmium and lead determination was carried out in order to test metal recoveries. Lead recoveries reached c.a 85% for UV digestion with hydrogen peroxide, 98% for digestion with anatase immobilized with polyvinylidene fluoride (N-metylo-2-pirolidon) and c.a 103% for digestion with immobilized anatase (anatase in gum). The results obtained showed the usefulness of TiO{sub 2} layer as an oxidation medium. An easy, cheap and eco-friendly digestion method of surfactants without any reagent has been developed, with equal sensitivity but and the same detection limit of traditional digestion methods.

  19. Structural and biomechanical effects of photooxidative collagen cross-linking with photosensitizer riboflavin and 370 nm UVA light on human corneoscleral tissues. (United States)

    Choi, Samjin; Shin, Jae-Ho; Cheong, Youjin; Jin, Kyung-Hyun; Park, Hun-Kuk


    This study quantitatively investigated the immediate effects of a photooxidative collagen cross-linking treatment with photosensitizer riboflavin (RF) and 370 nm UVA light in in vitro human corneoscleral collagen fibrils using histology, thickness, scanning electron microscopy, and atomic force microscopy analyses. Twenty 8 x 2 mm corneoscleral strips were dissected sagittally from donor tissue using a scalpel. Four parameters were investigated, including the density, thickness, adhesion force, and stiffness of corneoscleral tissues before and after the collagen cross-linking treatment. The RFUVA-catalyzed collagen cross-linking treatment led to an increase in the density of both corneal (8%) and scleral (23%) stromal collagens. However, there was no difference in corneoscleral thickness. Furthermore, RFUVA-catalyzed collagen cross-linking treatment led to an increased biomechanical response of corneosclera: 25 and 8% increases in corneoscleral stiffness, and 24 and 22% increases in corneoscleral adhesion force. The collagen cross-linking treatment through RF-sensitized photoreaction may cause structural and biomechanical changes in the collagen fibril network of the cornea and the sclera. This is due to narrowing of the interfibrillar spacing and the stromal edema.

  20. Photo-Oxidative Stress-Driven Mutagenesis and Adaptive Evolution on the Marine Diatom Phaeodactylum tricornutum for Enhanced Carotenoid Accumulation

    Directory of Open Access Journals (Sweden)

    Zhiqian Yi


    Full Text Available Marine diatoms have recently gained much attention as they are expected to be a promising resource for sustainable production of bioactive compounds such as carotenoids and biofuels as a future clean energy solution. To develop photosynthetic cell factories, it is important to improve diatoms for value-added products. In this study, we utilized UVC radiation to induce mutations in the marine diatom Phaeodactylum tricornutum and screened strains with enhanced accumulation of neutral lipids and carotenoids. Adaptive laboratory evolution (ALE was also used in parallel to develop altered phenotypic and biological functions in P. tricornutum and it was reported for the first time that ALE was successfully applied on diatoms for the enhancement of growth performance and productivity of value-added carotenoids to date. Liquid chromatography-mass spectrometry (LC-MS was utilized to study the composition of major pigments in the wild type P. tricornutum, UV mutants and ALE strains. UVC radiated strains exhibited higher accumulation of fucoxanthin as well as neutral lipids compared to their wild type counterpart. In addition to UV mutagenesis, P. tricornutum strains developed by ALE also yielded enhanced biomass production and fucoxanthin accumulation under combined red and blue light. In short, both UV mutagenesis and ALE appeared as an effective approach to developing desired phenotypes in the marine diatoms via electromagnetic radiation-induced oxidative stress.

  1. Photooxidation of farnesene mixtures in the presence of NOx: Analysis of reaction products and their implication to ambient PM2.5 (United States)

    U.S. Environmental Protection Agency — Chemical analysis of SOA produced from the irradiation of a mixture of α/β-farnesene/NOx was conducted in a 14.5 cubic meter smog chamber. SOA collected on...

  2. Mechanisms leading to oligomers and SOA through aqueous photooxidation: insights from OH radical oxidation of acetic acid and methylglyoxal

    Directory of Open Access Journals (Sweden)

    Y. Tan


    Full Text Available Previous experiments have demonstrated that the aqueous OH radical oxidation of methylglyoxal produces low volatility products including pyruvate, oxalate and oligomers. These products are found predominantly in the particle phase in the atmosphere, suggesting that methylglyoxal is a precursor of secondary organic aerosol (SOA. Acetic acid plays a central role in the aqueous oxidation of methylglyoxal and it is a ubiquitous product of gas phase photochemistry, making it a potential "aqueous" SOA precursor in its own right. However, the fate of acetic acid upon aqueous-phase oxidation is not well understood. In this research, acetic acid (20 μM–10 mM was oxidized by OH radicals, and pyruvic acid and methylglyoxal experimental samples were analyzed using new analytical methods, in order to better understand the formation of SOA from acetic acid and methylglyoxal. Glyoxylic, glycolic, and oxalic acids formed from acetic acid and OH radicals. In contrast to the aqueous OH radical oxidation of methylglyoxal, the aqueous OH radical oxidation of acetic acid did not produce succinic acid and oligomers. This suggests that the methylgloxal-derived oligomers do not form through the acid catalyzed esterification pathway proposed previously. Using results from these experiments, radical mechanisms responsible for oligomer formation from methylglyoxal oxidation in clouds and wet aerosols are proposed. The importance of acetic acid/acetate as an SOA precursor is also discussed. We hypothesize that this and similar chemistry is central to the daytime formation of oligomers in wet aerosols.

  3. Phosphorus(V) Porphyrin-Manganese(II) Terpyridine Conjugates: Synthesis, Spectroscopy, and Photo-Oxidation Studies on a SnO2 Surface. (United States)

    Poddutoori, Prashanth K; Lim, Gary N; Pilkington, Melanie; D'Souza, Francis; van der Est, Art


    A major challenge in designing artificial photosynthetic systems is to find a suitable mimic of the highly oxidizing photoactive species P680 in photosystem II. High-potential phosphorus(V) porphyrins have many attractive properties for such a mimic but have not been widely studied. Here, we report the synthesis and photophysical characterization of a novel phosphorus(V) octaethylporphyrin-oxyphenyl-terpyridine conjugate (PPor-OPh-tpy, 1) and its corresponding manganese(II) complex (PPor-OPh-Mn(tpy)Cl2, 2). The X-ray structure of 2 shows that the Mn(II) and P(V) centers are 11.783 Å apart and that the phenoxy linker is not fully conjugated with the terpyridine ligand. The porphyrin fluorescence in 1 and 2 is strongly quenched and has a shorter lifetime compared to a reference compound without the terpyridine ligand. This suggests that electron transfer from tpy or Mn(tpy) to the excited singlet state of the PPor may be occurring. However, femtosecond transient absorbance data show that the rate of relaxation to the ground state in 1 and 2 is comparable to the fluorescence lifetimes. Thus, if charge separation is occurring, its lifetime is short. Because both 1 and 2 are positively charged, they can be electrostatically deposited onto the surface of negatively charged SnO2 nanoparticles. Freeze-trapping EPR studies of 2 electrostatically bound to SnO2 suggest that excitation of the porphyrin results in electron injection from 1PPor* into the conduction band of SnO2 and that the resulting PPor•+ species acquires enough potential to photo-oxidize the axially bound Mn(II) (tpy) moiety to Mn(III) (tpy).

  4. The role of 2-methylglyceric acid and oligomer formation in the multiphase processing of secondary organic aerosol from isoprene and methacrolein photooxidation (CUMULUS project) (United States)

    Giorio, Chiara; Brégonzio-Rozier, Lola; Siekmann, Frank; Cazaunau, Mathieu; Temime-Roussel, Brice; Langley DeWitt, Helen; Gratien, Aline; Michoud, Vincent; Pangui, Edouard; Morales, Sébastien; Ravier, Sylvain; Zielinski, Arthur T.; Tapparo, Andrea; Vermeylen, Reinhilde; Claeys, Magda; Voisin, Didier; Salque-Moreton, Guillaume; Kalberer, Markus; Doussin, Jean-François; Monod, Anne


    Biogenic volatile organic compounds (BVOCs) undergo atmospheric processing and form a wide range of oxidised and water-soluble compounds. These compounds could partition into atmospheric water droplets, and react within the aqueous phase producing higher molecular weight and less volatile compounds which could remain in the particle phase after water evaporation (Ervens et al., 2011). The aim of this work was the molecular characterisation of secondary organic aerosol (SOA) formed from the photooxidation of isoprene and methacrolein during cloud evapo-condensation cycles. The experiments were performed within the CUMULUS project (CloUd MULtiphase chemistry of organic compoUndS in the troposphere), at the 4.2 m3 stainless steel CESAM chamber at LISA (Brégonzio-Rozier et al., 2016). In each experiment, isoprene or methacrolein was photooxidised with HONO and clouds have been produced to study oxidation processes in a multiphase environment that well simulates the interactions between VOCs, SOA particles and cloud droplets. During all the experiments, SOA was characterised online with a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and offline with gas chromatography mass spectrometry (GC-MS) and direct infusion nanoelectrospray ionisation high resolution mass spectrometry (nanoESI-HRMS). We observed that the main SOA compound in all experiments was 2-methylglyceric acid which undergoes oligomerisation reactions. A large number of long homologous series of oligomers were detected in all experiments, together with a complex co-oligomerised system made of monomers with a large variety of different structures. Comparison of SOA from multiphasic (smog chamber) experiments and samples from aqueous phase oxidation of methacrolein with •OH radical pointed out different types of oligomerisation reactions dominating the two different systems. Ervens et al. (2011) Atmos. Chem. Phys. 11, 11069 11102. Brégonzio-Rozier et al. (2016) Atmos. Chem. Phys

  5. Temperature Dependence of Light-Induced Absorbance Changes Associated with Chlorophyll Photooxidation in Manganese-Depleted Core Complexes of Photosystem II. (United States)

    Zabelin, A A; Shkuropatova, V A; Shkuropatov, A Ya; Shuvalov, V A


    Mid-infrared (4500-1150 cm(-1)) absorbance changes induced by continuous illumination of Mn-depleted core complexes of photosystem II (PSII) from spinach in the presence of exogenous electron acceptors (potassium ferricyanide and silicomolybdate) were studied by FTIR difference spectroscopy in the temperature range 100-265 K. The FTIR difference spectrum for photooxidation of the chlorophyll dimer P680 was determined from the set of signals associated with oxidation of secondary electron donors (β-carotene, chlorophyll) and reduction of the primary quinone QA. On the basis of analysis of the temperature dependence of the P680(+)/P680 FTIR spectrum, it was concluded that frequencies of 13(1)-keto-C=O stretching modes of neutral chlorophyll molecules PD1 and PD2, which constitute P680, are similar to each other, being located at ~1700 cm(-1). This together with considerable difference between the stretching mode frequencies of keto groups of PD1(+) and PD2(+) cations (1724 and 1709 cm(-1), respectively) is in agreement with a literature model (Okubo et al. (2007) Biochemistry, 46, 4390-4397) suggesting that the positive charge in the P680(+) dimer is mainly localized on one of the two chlorophyll molecules. A partial delocalization of the charge between the PD1 and PD2 molecules in P680(+) is supported by the presence of a characteristic electronic intervalence band at ~3000 cm(-1). It is shown that a bleaching band at 1680 cm(-1) in the P680(+)/P680 FTIR spectrum does not belong to P680. A possible origin of this band is discussed, taking into account the temperature dependence (100-265 K) of light-induced absorbance changes of PSII core complexes in the visible spectral region from 620 to 720 nm.

  6. BVOCs concentration in the Reunion Island tropical forests and the impact on photooxidants formation during the BIO-MAIDO 2015 campaign. (United States)

    Colomb, Aurelie; Duflot, Valentin; Tulet, Pierre; Flores, Olivier; Fournel, Jacques; Strasberg, Dominique; Deguillaume, Laurent; Vaitilingom, Mickael; Burnet, Frederic; Bourrianne, Thierry


    BVOCs from Reunion Forest and the role of BVOCs as precursors of photooxidants will be discussed.

  7. The knockdown of chloroplastic ascorbate peroxidases reveals its regulatory role in the photosynthesis and protection under photo-oxidative stress in rice. (United States)

    Caverzan, Andréia; Bonifacio, Aurenivia; Carvalho, Fabricio E L; Andrade, Claudia M B; Passaia, Gisele; Schünemann, Mariana; Maraschin, Felipe Dos Santos; Martins, Marcio O; Teixeira, Felipe K; Rauber, Rafael; Margis, Rogério; Silveira, Joaquim Albenisio Gomes; Margis-Pinheiro, Márcia


    The inactivation of the chloroplast ascorbate peroxidases (chlAPXs) has been thought to limit the efficiency of the water-water cycle and photo-oxidative protection under stress conditions. In this study, we have generated double knockdown rice (Oryza sativa L.) plants in both OsAPX7 (sAPX) and OsAPX8 (tAPX) genes, which encode chloroplastic APXs (chlAPXs). By employing an integrated approach involving gene expression, proteomics, biochemical and physiological analyses of photosynthesis, we have assessed the role of chlAPXs in the regulation of the protection of the photosystem II (PSII) activity and CO2 assimilation in rice plants exposed to high light (HL) and methyl violagen (MV). The chlAPX knockdown plants were affected more severely than the non-transformed (NT) plants in the activity and structure of PSII and CO2 assimilation in the presence of MV. Although MV induced significant increases in pigment content in the knockdown plants, the increases were apparently not sufficient for protection. Treatment with HL also caused generalized damage in PSII in both types of plants. The knockdown and NT plants exhibited differences in photosynthetic parameters related to efficiency of utilization of light and CO2. The knockdown plants overexpressed other antioxidant enzymes in response to the stresses and increased the GPX activity in the chloroplast-enriched fraction. Our data suggest that a partial deficiency of chlAPX expression modulate the PSII activity and integrity, reflecting the overall photosynthesis when rice plants are subjected to acute oxidative stress. However, under normal growth conditions, the knockdown plants exhibit normal phenotype, biochemical and physiological performance. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  8. Photochemical aging of secondary organic aerosols generated from the photooxidation of polycyclic aromatic hydrocarbons in the gas-phase. (United States)

    Riva, Matthieu; Robinson, Ellis S; Perraudin, Emilie; Donahue, Neil M; Villenave, Eric


    Aging processes of secondary organic aerosol (SOA) may be a source of oxygenated organic aerosols; however, the chemical processes involved remain unclear. In this study, we investigate photochemical aging of SOA produced by the gas-phase oxidation of naphthalene by hydroxyl radicals and acenaphthylene by ozone. We monitored the SOA composition using a high-resolution time-of-flight aerosol mass spectrometer. We initiated SOA aging with UV photolysis alone and with OH radicals in the presence or absence of light and at different NOx levels. For naphthalene, the organic composition of the particulate phase seems to be dominated by highly oxidized compounds such as carboxylic acids, and aging data may be consistent with diffusion limitations. For acenaphthylene, the fate of oxidized products and the moderately oxidized aerosol seem to indicate that functionalization reactions might be the main aging process were initiated by the cumulative effect of light and OH radicals.

  9. Sulfur dioxide adsorption and photooxidation on isotopically-labeled titanium dioxide nanoparticle surfaces: roles of surface hydroxyl groups and adsorbed water in the formation and stability of adsorbed sulfite and sulfate. (United States)

    Nanayakkara, Charith E; Pettibone, John; Grassian, Vicki H


    Transmission FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS) are used to probe the details of sulfur dioxide adsorption and photooxidation on titanium dioxide nanoparticle surfaces. Adsorption sites, surface speciation and photooxidation chemistry have been determined from analysis of FTIR spectra in conjunction with isotope labeling experiments. These data show that surface hydroxyl groups are involved in the adsorption of sulfur dioxide, and in particularly, sulfur dioxide reacts with either one surface O-H group to yield adsorbed bisulfite or two surface O-H groups to yield adsorbed sulfite and water. Using (16)O-H, (16)O-D and (18)O-H labeled surface O-H groups, additional insights into the adsorption mechanism as well as shifts in the vibrational modes of adsorbed sulfite have been determined. Upon irradiation, adsorbed sulfite/bisulfite converts to adsorbed sulfate. The relative stability of adsorbed sulfite to adsorbed sulfate on TiO2 nanoparticle surfaces was also examined in the presence of increasing relative humidity (RH). It is shown here that adsorbed water can more easily displace sulfite compared to sulfate by forming a stable sulfur dioxide water complex in the presence of adsorbed water. These differences in the RH-dependent stability of adsorbed species that form as a result of surface heterogeneous reactions on oxide particles surfaces has important implications in the heterogeneous chemistry of mineral dust aerosol in the atmosphere.

  10. Relative humidity-dependent viscosity of secondary organic material from toluene photo-oxidation and possible implications for organic particulate matter over megacities

    Energy Technology Data Exchange (ETDEWEB)

    Song, Mijung; Liu, Pengfei F.; Hanna, Sarah J.; Zaveri, Rahul A.; Potter, Katie; You, Yuan; Martin, Scot T.; Bertram, Allan K.


    To improve predictions of air quality, visibility, and climate change, knowledge of the viscosities and diffusion rates within organic particulate matter consisting of secondary organic material (SOM) is required. Most qualitative and quantitative measurements of viscosity and diffusion rates within organic particulate matter have focused on SOM particles generated from biogenic volatile organic compounds (VOCs) such as α-pinene and isoprene. In this study, we quantify the relative humidity (RH)-dependent viscosities at 295±1K of SOM produced by photo-oxidation of toluene, an anthropogenic VOC. The viscosities of toluene-derived SOM were 2 × 10₋1 to ~6 ×106Pa s from 30 to 90%RH, and greater than ~2 × 108 Pa s (similar to or greater than the viscosity of tar pitch) for RH ≤ 17%. These viscosities correspond to Stokes–Einstein-equivalent diffusion coefficients for large organic molecules of ~2 ×10₋15cm2s₋1 for 30 % RH, and lower than ~3 × 10₋17cm2s₋1 for RH ≤ 17 %. Based on these estimated diffusion coefficients, the mixing time of large organic molecules within 200 nm toluene-derived SOM particles is 0.1–5 h for 30% RH, and higher than ~100 h for RH ≤ 17%. As a starting point for understanding the mixing times of large organic molecules in organic particulate matter over cities, we applied the mixing times determined for toluene-derived SOM particles to the world's top 15 most populous megacities. If the organic particulate matter in these megacities is similar to the toluene-derived SOM in this study, in Istanbul, Tokyo, Shanghai, and São Paulo, mixing times in organic particulate matter during certain periods of the year may be very short, and the particles may be well-mixed. On the other hand, the mixing times of large organic molecules in organic particulate matter in Beijing, Mexico City, Cairo, and Karachi may be long

  11. Real refractive indices and volatility of secondary organic aerosol generated from photooxidation and ozonolysis of limonene, α-pinene and toluene

    Directory of Open Access Journals (Sweden)

    H. Kim


    Full Text Available Thermodenuding particles can provide insights into aerosol composition and may be a way to create particles in laboratory chambers that better mimic the atmosphere. The relative volatility of secondary organic aerosol (SOA was investigated by evaporating organics from the particles using a thermodenuder (TD at temperatures between ∼60 and 100 °C. Volatility was influenced by the parent hydrocarbon, oxidation chemistry and relative humidity (RH. For SOA generated from ozonolysis, limonene had lower volatility than α-pinene, and OH scavengers had no influence on volatility. For photooxidation, α-pinene SOA was slightly more volatile than limonene SOA. Increasing RH also modestly increased volatility, while toluene SOA was unaffected by heating to 98 °C. For both α-pinene and limonene, the concentration of NOx and the HC / NOx ratio had no discernible effect on SOA volatility. Refractive indices for the original and denuded particles were retrieved from polar nephelometer measurements using parallel and perpendicular polarized 532 nm light. Retrievals were performed with a genetic algorithm method using Mie–Lorenz scattering theory and measured particle size distributions. Retrieved refractive indices for the SOA before thermodenuding varied between 1.35 and 1.61 depending on several factors, including parent hydrocarbon, oxidation chemistry, and SOA generation temperature. For high NOx SOA, as particles shrink, their refractive index returns to the value of the corresponding size particles before heating (limonene or slightly higher (α-pinene. For low NOx however, the resulting refractive index is 0.05 ± 0.02 lower than the corresponding size undenuded particles. Additionally, for α-pinene SOA from ozonolysis with OH radical scavenger, resulting refractive indices were higher by about 0.03 after heating. Consistent with no change in size, refractive indices of toluene SOA were unaffected by heating. Finally, refractive index data

  12. Synthesis, autoxidation and photooxidation of hindered pyrrole derivatives. Hindered pyrrolic nitroxide radicals; Synthese, autoxydation et photoxidation de pyrroles encombres radicaux nitroxydes pyrroliques encombres

    Energy Technology Data Exchange (ETDEWEB)

    Ramasseul, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires


    2,5-di-t-butyl and 2,3,5-tri-t-butyl pyrrole are prepared from pinacoline and their structure is confirmed by comparison with 2,5-di-t-butyl furan and thiophene (I.R., U.V. and N.M.R. {sup 13}C satellites observation giving J{sub 13{sub C-H}} and J{sub H{sub 3}-H{sub 4}}). The sensitized photooxidation of these hindered pyrroles gives corresponding hydroperoxides which most likely structure is determined using physical and chemical methods. Oxidation of 2,5-di-t-butyl and 2,3,5-tri-t-butyl pyrrole by hydrogen peroxide in presence of inorganic per-acid of by p-nitro-perbenzoic acid does not give the pyrrolic nitroxides in contrast with secondary amines. Some N-hydroxypyrroles are then prepared from pinacoline and ethyl pivaloyl-acetate. Their oxidation by lead dioxide gives the corresponding pyrrolic nitroxides. 2,5-di-t-butyl 3,4-di-ethoxycarbonyl pyrryl 1-oxy is isolated and studied spectroscopically (visible and U.V., E.P.R.). In marked contrast with ordinary nitroxides it does not show solvent effect. It can be compared with 2,4-di-t-butyl cyclopentadienone, a carbon analog. For both, the long wave length transition does not show the usual n - {pi}* behaviour; that is confirmed by E.P.R. Using Huckel method for pyrrolic nitroxide skeleton, it is possible to have a good interpretation of experimental data. (author) [French] Les di-t-butyl 2,5 et tri-t-butyl-2,3,5 pyrrole sont synthetises a partir de la pinacoline et leur structure confirmee par comparaison avec les di-t-butyl-2,5 furanne et thiophene (I.R., U.V. et R.M.N.: observation des satellites {sup 13}C conduisant a la mesure des J{sub 13{sub C-H}} et J{sub H{sub 3}{sub -H{sub 4}}). La photoxydation sensibilisee de ces pyrroles encombres conduit aux hydroperoxydes correspondants dont la structure la plus probable est determinee par les methodes physicochimiques. L'oxydation des di-t-butyl-2,5 et tri-t-butyl-2,3,5 pyrrole par l'eau oxygenee en presence de peracide mineral ou par l'acide p

  13. The formation of SOA and chemical tracer compounds from the photooxidation of naphthalene and its methyl analogs in the presence and absence of nitrogen oxides

    Directory of Open Access Journals (Sweden)

    T. E. Kleindienst


    Full Text Available Laboratory smog chamber experiments have been carried out to investigate secondary organic aerosol (SOA formation from the photooxidation of naphthalene and its methyl analogs, 1- and 2-methylnaphthalene (1-MN and 2-MN, respectively. Laboratory smog chamber irradiations were conducted in a flow mode to ensure adequate collection of the aerosol at reasonably low reactant concentrations and in the presence and absence of nitrogen oxides. Phthalic acid and methyl analogs were identified following BSTFA derivatization of the aerosol extract. These compounds were examined to determine whether they could serve as reasonable molecular tracers to estimate the contributions of these precursors to ambient PM2.5. Measurements were also made to determine aerosol parameters from secondary organic aerosol from naphthalene, 1-MN, and 2-MN.

    A mass fraction approach was used to establish factors which could be applied to phthalic acid concentrations in ambient aerosols, assuming a negligible contribution from primary sources. Phthalic anhydride uptake (and hydrolysis was tested and found to represent a moderate filter artifact in filter measurements with and without in-line denuders. This study provided the opportunity to examine differences using authentic standards for phthalic acid compared to surrogate standards. While the mass fraction based on a surrogate compounds was somewhat lower, the differences are largely unimportant. For naphthalene, mass fractions of 0.0199 (recommended for ambient samples and 0.0206 were determined in the presence and absence of nitrogen oxides, respectively, based on phthalic acid standards.

    The mass fractions determined from the laboratory data were applied to ambient samples where phthalic acid was found and expressed "as naphthalene" since phthalic acid was found to be produced in the particle phase from other methylnaphthalenes. The mass fraction values were applied to samples taken during the

  14. Dityrosine, 3,4-dihydroxyphenylalanine (DOPA), and radical formation from tyrosine residues on milk proteins with globular and flexible structures as a result of riboflavin-mediated photo-oxidation

    DEFF Research Database (Denmark)

    Dalsgaard, Trine K; Nielsen, Jacob H; Brown, Bronwyn E


    Riboflavin-mediated photo-oxidative damage to protein Tyr residues has been examined to determine whether protein structure influences competing protein oxidation pathways in single proteins and protein mixtures. EPR studies resulted in the detection of Tyr-derived o-semiquione radicals...... proteins, BSA and β-lactoglobulin. In contrast, samples with β-casein gave higher yields of dityrosine than samples containing BSA and β-lactoglobulin. These results indicate that the flexible structure of β-casein favors radical-radical termination of tyrosyl radicals to give dityrosine, whereas the less...... flexible structure of globular proteins decreases the propensity for tyrosyl radicals to dimerize, with this resulting in higher yields of DOPA and its secondary radical....

  15. Glutathione (GSH Production as Protective Adaptation Against Light Regime Radiation of Symbiodinium Natural Population

    Directory of Open Access Journals (Sweden)

    Moh Muhaemin


    Full Text Available Glutathione (GSH, as a wide range of low molecular weight, which found in marine microalgae and event bacteria, are essential to prevent photooxidation and productivity loss from these Radical Oxigen Species (ROS. Symbiodinium, endo-symbiont of corals, were exposed with different UV radiation combined with irradiance treatments to explore biomass specific initial response. Intracellular glutahione was observed as potential adaptive response of Symbiodinium population under environmental specific stress. The result showed that GSH production increased significantly with increasing irradiance and/or UV levels. GSH concentration was fluctuated among populations exposed by different irradiance treatments, but not effected by UV and irradiance exposure. GSH production as a response of UV exposure was higher than irradiance treatments. Both these high correlative fluctuation of intracellular GSH production and the presence of both treatments indicated protective specific adaptation of Symbiodinium under specific environmental stress, respectively.   Keywords: zooxanthellae, irradiance, glutathione (GSH, corals, Fungia

  16. Comparative profiling of biomarker psoralen in antioxidant active ...

    African Journals Online (AJOL)

    Materials and Methods: HPTLC studies were carried out using CAMAG HPTLC system on Glass-backed silica gel 60F254 HPTLC pre-coated plates using selected mobile phase toluene: methanol (9:1). The antioxidant activity was carried out, using DPPH free radical method. Results: Among all the five species of genus ...

  17. Treatment of necrobiosis lipoidica with topical psoralen plus ultraviolet A

    NARCIS (Netherlands)

    de Rie, M. A.; Sommer, A.; Hoekzema, R.; Neumann, H. A. M.


    Background Necrobiosis lipoidica (NL) is a rare skin disease, mostly seen on the legs and often occurring in patients with diabetes mellitus. The disease belongs to the idiopathic cutaneous palisading granulomatous dermatitides associated with a degeneration of collagen, thus leading to skin

  18. Use of Doehlert and constrained mixture designs in the development of a photo-oxidation procedure using UV radiation/H₂O₂ for decomposition of landfill leachate samples and determination of metals by flame atomic absorption spectrometry. (United States)

    Bezerra, Marcos A; Souza, Antônio D S; Oliveira, Rafael V; Oliveira, Djalma M; Cardoso, Luiz A M; Sousa Filho, Hélio R


    This work proposes the use of photo-oxidation degradation with UV radiation/H2O2 as sample treatment for the determination of Fe, Zn, Mn, Ni and Co in municipal solid waste landfill leachate by flame atomic absorption spectrometry (FAAS). Three variables (pH, irradiation time and buffer concentration) were optimized using Doehlert design and the proportions of mixture components submitted to UV radiation (leachate sample, buffer solution and H2O2 30%, v/v) were optimized using a constrained mixture design. Using the experimental conditions established, this procedure allows limits of detection of 0.075, 0.025, 0.010, 0.075 and 0.041 µg mL-1, and the precision levels expressed as relative standard (%RSD, 0.5 µg mL-1) were 3.6, 1.8, 1.3, 3.3 and 1.7%, for Fe, Mn, Zn, Ni and Co respectively. Recovery tests were carried out for evaluation of the procedure accuracy and recoveries were between 92 and 106% for the studied metals. This procedure has been applied for the analysis of the landfill leachate collected in Jequié, a city of the southwestern region of the State of Bahia, Brazil. The results were compared with those obtained by acid digestion. There was no significant difference between the results obtained by the two methods based on paired t-test at 95% confidence level.

  19. Use of Doehlert and constrained mixture designs in the development of a photo-oxidation procedure using UV radiation/H2O2 for decomposition of landfill leachate samples and determination of metals by flame atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Marcos A. Bezerra


    Full Text Available This work proposes the use of photo-oxidation degradation with UV radiation/H2O2 as sample treatment for the determination of Fe, Zn, Mn, Ni and Co in municipal solid waste landfill leachate by flame atomic absorption spectrometry (FAAS. Three variables (pH, irradiation time and buffer concentration were optimized using Doehlert design and the proportions of mixture components submitted to UV radiation (leachate sample, buffer solution and H2O2 30%, v/v were optimized using a constrained mixture design. Using the experimental conditions established, this procedure allows limits of detection of 0.075, 0.025, 0.010, 0.075 and 0.041 µg mL-1, and the precision levels expressed as relative standard (%RSD, 0.5 µg mL-1 were 3.6, 1.8, 1.3, 3.3 and 1.7%, for Fe, Mn, Zn, Ni and Co respectively. Recovery tests were carried out for evaluation of the procedure accuracy and recoveries were between 92 and 106% for the studied metals. This procedure has been applied for the analysis of the landfill leachate collected in Jequié, a city of the southwestern region of the State of Bahia, Brazil. The results were compared with those obtained by acid digestion. There was no significant difference between the results obtained by the two methods based on paired t-test at 95% confidence level.

  20. Photo-oxidation of SO{sub 2} and of SO{sub 2} trapped in amorphous water ice studied by IR spectroscopy. Implications for Jupiter's satellite Europa

    Energy Technology Data Exchange (ETDEWEB)

    Schriver-Mazzuoli, L. [Univ. Pierre et Marie Curie, Lab. de Physique Moleculaire et Applications, Paris (France); Univ. Paris Nord, Lab. d' Etude des Nuisances Atmospheriques et de leurs Effets, Bobigny (France); Schriver, A.; Chaabouni, H. [Univ. Pierre et Marie Curie, Lab. de Physique Moleculaire et Applications, Paris (France)


    Fourier Transform Infrared Spectroscopy (FTIR), is used to characterize thin films of sulfur dioxide trapped in excess of amorphous water ice and to study the photo-oxidation of pure solid SO{sub 2} or of SO{sub 2} diluted in water ice. These laboratory experiments were undertaken in an attempt to find information on the formation of hydrated sulfuric acid detected on Europa's surface. Vibrational spectra at 30 K of mixed films containing SO{sub 2} with an excess of water depend on the deposition conditions. A metastable (SO{sub 2}){sub m}(H{sub 2}O){sub n} phase and a solid solution of SO{sub 2} in water ice have been evidenced. Irradiation at 266 nm of mixed films SO{sub 2}/O{sub 3}/H{sub 2}O produces sulfur trioxide and hydrogen peroxide without traces of sulfuric acid. Irradiation of films of pure SO{sub 2}, under 200 nm, leads to sulfur trioxide and to ozone. When SO{sub 2} is diluted in amorphous water ice, new weak bands that appear after irradiation suggest the formation of sulfuric acid. (author)

  1. Redox changes in the chloroplast and hydrogen peroxide are essential for regulation of C(3)-CAM transition and photooxidative stress responses in the facultative CAM plant Mesembryanthemum crystallinum L. (United States)

    Slesak, Ireneusz; Karpinska, Barbara; Surówka, Ewa; Miszalski, Zbigniew; Karpinski, Stanislaw


    Mesembryanthemum crystallinum, a facultative halophyte and C(3)-Crassulacean acid metabolism (CAM) intermediate plant, has become a favoured plant for studying stress response mechanisms during C(3)-CAM shifts. One hour of exposure to excess light (EL) caused inhibition of photosynthetic electron transport in M. crystallinum leaves as indicated by chlorophyll a fluorescence measurements. This was accompanied by an increase in NADP-malic enzyme (ME), one of the key cytosolic enzymes involved in CAM, and by a general increase in superoxide dismutase (SOD) activity. In contrast, NAD-ME activity (the mitochondrial form of ME) was not affected by EL. Exposure to EL and 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB) treatment of a whole plant in low light induced hydrogen peroxide (H(2)O(2)) and C(3) to CAM transition. In contrast, treatment with 3-3,4-dichlorophenyl-1,1-dimethyl urea (DCMU) has blocked high light-induced H(2)O(2) accumulation and C(3)-CAM transition. Moreover, the abundance of transcripts encoding different SODs, ascorbate peroxidase and SOD activity was differently regulated by DCMU and DBMIB. Results of applying EL or high light, H(2)O(2) and photosynthetic electron transport inhibitors suggest that the redox events in the vicinity of PSII and/or PSI and photo-produced H(2)O(2) play a major role in the regulation of C(3)-CAM transition and photooxidative stress responses in M. crystallinum.

  2. α-pinene photooxidation under controlled chemical conditions - Part 1: Gas-phase composition in low- and high-NOx environments (United States)

    Eddingsaas, N. C.; Loza, C. L.; Yee, L. D.; Seinfeld, J. H.; Wennberg, P. O.


    The OH oxidation of α-pinene under both low- and high-NOx environments was studied in the Caltech atmospheric chambers. Ozone was kept low to ensure OH was the oxidant. The initial α-pinene concentration was 20-50 ppb to ensure that the dominant peroxy radical pathway under low-NOx conditions is reaction with HO2, produced from reaction of OH with H2O2, and under high-NOx conditions, reactions with NO. Here we present the gas-phase results observed. Under low-NOx conditions the main first generation oxidation products are a number of α-pinene hydroxy hydroperoxides and pinonaldehyde, accounting for over 40% of the yield. In all, 65-75% of the carbon can be accounted for in the gas phase; this excludes first-generation products that enter the particle phase. We suggest that pinonaldehyde forms from RO2 + HO2 through an alkoxy radical channel that regenerates OH, a mechanism typically associated with acyl peroxy radicals, not alkyl peroxy radicals. The OH oxidation and photolysis of α-pinene hydroxy hydroperoxides leads to further production of pinonaldehyde, resulting in total pinonaldehyde yield from low-NOx OH oxidation of ~33%. The low-NOx OH oxidation of pinonaldehyde produces a number of carboxylic acids and peroxyacids known to be important secondary organic aerosol components. Under high-NOx conditions, pinonaldehyde was also found to be the major first-generation OH oxidation product. The high-NOx OH oxidation of pinonaldehyde did not produce carboxylic acids and peroxyacids. A number of organonitrates and peroxyacyl nitrates are observed and identified from α-pinene and pinonaldehyde.

  3. TiO2@Pt@CeO2 nanocomposite as a bifunctional catalyst for enhancing photo-reduction of Cr (VI) and photo-oxidation of benzyl alcohol. (United States)

    Li, Shunxing; Cai, Jiabai; Wu, Xueqing; Liu, Biwen; Chen, Qiaoying; Li, Yuehai; Zheng, Fengying


    An solar-light-driven and bifunctional photocatalyst was designed for photo-reduction of Cr(VI) and selective photo-oxidation of benzyl alcohol into benzaldehyde in the presence of water under ambient conditions. Double-shelled and sandwiched TiO2@Pt@CeO2 hollow spheres were prepared by using functionalized polystyrene spheres, sol-gel, hydrothermal reaction, and calcination. The Pt nanoparticles (NPs) were controllably loaded between the TiO2 shell and CeO2 shell. Under solar-light irradiation, the photo-reduction rate of Cr(VI) (μmol h-1) was in the order of TiO2@Pt@CeO2 (1.901) > TiO2@CeO2 (1.424) > TiO2 (1.040) > CeO2 (0.992). Among the above-mentioned photocatalysts, the conversion rate of benzyl alcohol for TiO2@Pt@CeO2 was also the best. These results were attributed to the combination of TiO2 and CeO2 as photocatalyst and oxygen buffer, the double-shelled and sandwiched nanostructure, and the addition of Pt NPs as cocatalyst and electron trap site, which could store and shuttle photo-generated electrons, reduce the recombination of the electron-hole, and then enhance photo-generation of active radicals. This conclusion was verified by the electron paramagnetic resonance (EPR) spectroscopy. Considering the versatile combination of photocatalyst, oxygen buffer and cocatalyst, this work could provide new insights into the design of high-performance bifunctional photocatalysts for heavy metal removal and selective synthesis. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Certain photooxidized derivatives of tryptophan bind with very high affinity to the Ah receptor and are likely to be endogenous signal substances

    Energy Technology Data Exchange (ETDEWEB)

    Rannug, A.; Rannug, U.; Rosenkranz, H.S.; Winqvist, L.; Westerholm, R.; Agurell, E.; Grafstroem, A.K.


    The purpose of the present study was to determine whether ultraviolet light (UV) irradiation of amino acids produces compounds with affinity for the Ah receptor. Aqueous solutions of L-tryptophan were exposed to radiation from an unfiltered high-pressure mercury lamp. The photoproducts formed were solvent-extracted or concentrated on Sep-Pak C18 cartridges. The concentrated extracts or eluants were treated for their ability to compete with /sup 3/H-labeled 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Binding was assayed in liver cytosolic preparations from Sprague-Dawley rats using a technique based on hydroxylapatite separation. Photoproducts with receptor affinity were formed in a time-dependent manner. Histidine and tryptamine also gave products upon UV irradiation that competed with TCDD. Commercial tryptophan, at least aged, contained trace amounts of impurities with receptor affinity. Analysis by TLC and high-pressure liquid chromatography of the photo-products of tryptophan showed a minimum of three different binding compounds. Two of the products were studied in greater detail. One of them, showing UV absorbance and yellow fluorescence, gave a molecular ion (M+) of 284 and the other gave M+ 312 but showed little UV absorption and fluorescence. The concentration, based on mass spectrometry quantifications, of the two compounds that displaced more than 50% of TCDD was found to be extremely low, giving Kd values of 0.44 nM (M+ 312) and 0.07 nM (M+ 284). The existence of high affinity receptors for oxidized amino acids is postulated and their possible role in the proliferative cellular responses to TCDD and tryptophan is discussed briefly.

  5. Peroxyl radical- and photo-oxidation of glucose 6- phosphate dehydrogenase generates cross-links and functional changes via oxidation of tyrosine and tryptophan residues

    DEFF Research Database (Denmark)

    Leinisch, Fabian; Mariotti, Michele; Rykær, Martin


    indicate that pathophysiological processes and multiple human diseases are associated with the accumulation of damaged proteins. In this study we investigated the mechanisms and consequences of exposure of the key metabolic enzyme glucose-6-phosphate dehydrogenase (G6PDH) to peroxyl radicals (ROO...... consumption and formation of oxygenated products (diols, peroxides, N-formylkynurenine, kynurenine) from Trp, and di-tyrosine (from Tyr). Mass spectrometric data obtained after trypsin-digestion in the presence of H216O and H218O, has allowed the mapping of specific cross-linked residues and their locations...

  6. α-pinene photooxidation under controlled chemical conditions – Part 1: Gas-phase composition in low- and high-NOx environments


    P. O. Wennberg; J. H. Seinfeld; L. D. Yee; N. C. Eddingsaas; C. L. Loza


    The OH oxidation of α-pinene under both low- and high-NOx environments was studied in the Caltech atmospheric chambers. Ozone was kept low to ensure OH was the oxidant. The initial α-pinene concentration was 20–50 ppb to ensure that the dominant peroxy radical pathway under low-NOx conditions is reaction with HO2 and under high-NOx conditions, reactions with NO. Here we present the gas-phase results observed. Under low-NOx conditions the main first generation oxidation products are α-pinene h...

  7. Effects of inorganic seed aerosols on the particulate products of aged 1,3,5-trimethylbenzene secondary organic aerosol (United States)

    Huang, Mingqiang; Hao, Liqing; Cai, Shunyou; Gu, Xuejun; Zhang, Weixiong; Hu, Changjin; Wang, Zhenya; Fang, Li; Zhang, Weijun


    Inorganic aerosols such as (NH4)2SO4, NaNO3 and CaCl2 are commonly present in the Chinese urban atmosphere. They could significantly affect the formation and aging of ambient secondary organic aerosols (SOA), but the underlying mechanisms remain unknown. In this work we studied SOA formation from the photooxidation reaction of 1,3,5-trimethylbenzene (135-TMB) with 100 μg/m3 of the above three types of inorganic aerosols as seeds in a laboratory chamber. We focused on the aging products of SOA particles by exposing them to high levels of oxidizing hydroxyl radicals (OH). The particulate products of SOA were measured using an aerosol laser time-of-flight mass spectrometer (ALTOFMS) and Fuzzy C-Means (FCM) were applied to organic mass spectra for clustering. In the presence of (NH4)2SO4 seeds, 4-methyl-1H-imidazole, 4-methyl-imidazole-2-acetaldehyde and other imidazole derivative compounds formed from reactions of NH4+ with methylglyoxal were detected as new aged products. We also observed aromatic nitrogen-containing organic compounds as the major aged products in the presence of NaNO3 seeds as a consequence of reaction with OH and NO2 radicals, which were generated by UV irradiation of acidic aqueous nitrate, inducing nitration reactions with phenolic compounds. As CaCl2 has the strongest hygroscopic properties of the three salt particles tested, the greater water content on the surface of the aerosol may facilitate the condensing of more gas-phase organic acid products to the hygroscopic CaCl2 seeds, forming H+ ions that catalyze the heterogeneous reaction of aldehydes, products of photooxidation of 135-TMB, and forming high-molecular-weight (HMW) compounds. These results provide new insight into the aromatic SOA aging mechanisms.

  8. An upper limit for the rate coefficient of the reaction of NH2 radicals with O2 using FTIR product analysis (United States)

    Tyndall, G. S.; Orlando, J. J.; Nickerson, Karen E.; Cantrell, C. A.; Calvert, J. G.


    Fourier transform infrared spectrometry has been used to study the products of the photooxidation of ammonia in the presence of oxygen at 296 K. The data have been used to derive an upper limit of 6 x 10 exp -21/cu cm molecule s for the reaction of NH2 radicals with O2 to produce NO(x) at 296 K. This upper limit, which is three orders of magnitude lower than previous estimates based on the kinetics of NH2 loss, rules out the importance of this reaction in the atmosphere and suggests that NH2 will be oxidized by O3 or NO2. The effect on the NO(x) and N2O budgets depends critically on the products of the NH2 + O3 reaction. Simulations of the experimental product yields also allow an evaluation of possible product channels for the reaction of NH2 with HO2.

  9. ­­Secondary organic aerosol formation from photo-oxidation of wood combustion emissions: Characterization of gas phase precursors and their link to SOA budget (United States)

    Bhattu, D.; Stefenelli, G.; Zotter, P.; Zhou, J.; Nussbaumer, T.; Bertrand, A.; Marchand, N.; Termine-Roussel, B.; Baltensperger, U.; Slowik, J.; Prevot, A. S.; El-Haddad, I.; Dommen, J.


    Current legislation limits the emission of particulate matter, but does not regulate the precursors potentially forming secondary organic aerosol (SOA). Recent literature has shown that only 22 non-traditional SOA precursors from residential wood combustion explains 84-116% of the observed SOA mass whereas traditional precursors in the models account for only 3-27% of the SOA mass (Bruns et al., 2016). Investigation of gas phase emissions from wood combustion and their SOA formation potential have largely focused on single combustion devices with limited operating conditions. As, both primary emissions and SOA formation is a strong function of device type, load, fuel and operating conditions, we have performed a detailed chamber study investigating the gas-phase precursors from beech wood using three combustion devices namely a pellet boiler (combustion conditions: optimum, lack and excess of oxygen), an industrial wood chip grate boiler (30% and 100% power), and a log wood stove (varying fuel load and moisture content) using a potential aerosol mass reactor (PAM) with varying OH exposure. The short residence time in the reactor allowed a time resolved picture of SOA production potential and reduced wall losses. The main aim of this study is to characterize the primary and aged gaseous emissions and investigate their SOA formation potential depending on their mass yield, molecular structures, functional groups and OH reactivity in order to ascertain the contribution of residential wood burning in total carbonaceous OA budget. The physical and chemical effects of different OA aging conditions were monitored using an SMPS, an Aethalometer, an HR-ToF-AMS, as well as a PTR-ToF-MS and other gas monitors. In pellet boiler, significant SOA mass enhancement is observed in excess oxygen conditions compared to optimum and oxygen deprived conditions. Highest gas phase emissions from wood stove are observed at cold start (start of each burn cycle) and lowest in burn out phase


    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  11. Advanced Wastewater Photo-oxidation System Project (United States)

    National Aeronautics and Space Administration — Pioneer Astronautics proposes an advanced photocatalytic oxidation reactor for enhancing the reliability and performance of Water Recovery Post Processing systems...

  12. Prebiotic Metabolism: Production by Mineral Photoelectrochemistry of α-Ketocarboxylic Acids in the Reductive Tricarboxylic Acid Cycle (United States)

    Guzman, Marcelo I.; Martin, Scot T.


    A reductive tricarboxylic acid (rTCA) cycle could have fixed carbon dioxide as bio chemically useful energy-storage molecules on early Earth. Nonenzymatic chemical pathways for some steps of the rTCA cycle, however, such as the production of the α-ketocarboxylic acids pyruvate and α-ketoglutarate, remain a challenging problem for the viability of the proposed prebiotic cycle. As a class of compounds, α-ketocarboxylic acids have high free energies of formation that disfavor their production. We report herein the production of pyruvate from lactate and of α-ketoglutarate from pyruvate in the millimolar concentration range as promoted by ZnS mineral photoelectrochemistry. Pyruvate is produced from the photooxidation of lactate with 70% yield and a quantum efficiency of 0.009 at 15°C across the wavelength range of 200-400 nm. The produced pyruvate undergoes photoreductive back reaction to lactate at a 30% yield and with a quantum efficiency of 0.0024. Pyruvate alternatively continues in photooxidative forward reaction to α-ketoglutarate with a 50% yield and a quantum efficiency of 0.0036. The remaining 20% of the carbon follows side reactions that produce isocitrate, glutarate, and succinate. Small amounts of acetate are also produced. The results of this study suggest that α-ketocarboxylic acids produced by mineral photoelectrochemistry could have participated in a viable enzyme-free cycle for carbon fixation in an environment where light, sulfide minerals, carbon dioxide, and other organic compounds interacted on prebiotic Earth.

  13. Avaliação da degradação térmica e fotooxidativa do ABS para fins de reciclagem Evaluation of thermal and photo-oxidative ABS degradation with recycling purposes

    Directory of Open Access Journals (Sweden)

    Elisabete Maria Saraiva Sanchez


    Full Text Available Este trabalho tem como objetivo avaliar a degradação térmica e fotooxidativa do terpolímero poli (acrilonitrila-butadieno-estireno, ABS, utilizado em componentes internos de automóveis. Corpos de prova de ABS moldados por injeção foram submetidos ao envelhecimento térmico, segundo a norma ASTM D794, e ao envelhecimento fotooxidativo segundo as normas ASTM G24 e G53. As amostras envelhecidas foram submetidas às análises dinâmico-mecânica, e microscópicas por microscopia de força atômica no modo não contato. Os resultados mostraram que as transições, tanto da fase vítrea quanto da fase elastomérica na superfície do ABS, são afetadas pela degradação. As áreas dos picos das curvas de módulo de perda em função da temperatura relativos às transições vítreas do ABS foram correlacionadas ao alongamento na ruptura, em função do tempo e tipo de envelhecimento. As propriedades mecânicas são influenciadas de forma mais acentuada pela extensão da degradação da matriz. O método de envelhecimento ASTM G24 mostrou-se mais agressivo que o G53, seja para a fase BR ou para a fase SAN. As imagens microscópicas mostraram que os diferentes envelhecimentos provocaram diferentes variações na rugosidade das superfícies. Amostras fotooxidadas, com perda de alongamento maior que 50%, foram reprocessadas e mostraram uma recuperação superior a 90% nessa propriedade.The aim of this work is the evaluation of thermal and photo-oxidative degradation of the terpolymer acrylonitrile-butadiene-styrene, ABS, used in internal automotive components. Injection molded specimens were aged by ASTM D794, ASTM G24 and ASTM G53 standards. The aged test specimens were studied by means of dynamic mechanical analysis and non-contact atomic force microscopy. The results revealed that the transitions of the glass and rubber phases were affected by the degradation. The area under linear loss modulus-temperature curves was related to tensile properties

  14. Low pressure UV/H2O2 treatment for the degradation of the pesticides metaldehyde, clopyralid and mecoprop - Kinetics and reaction product formation. (United States)

    Semitsoglou-Tsiapou, Sofia; Templeton, Michael R; Graham, Nigel J D; Hernández Leal, Lucía; Martijn, Bram J; Royce, Alan; Kruithof, Joop C


    The degradation kinetics of three pesticides - metaldehyde, clopyralid and mecoprop - by ultraviolet photolysis and hydroxyl radical oxidation by low pressure ultraviolet hydrogen peroxide (LP-UV/H2O2) advanced oxidation was determined. Mecoprop was susceptible to both LP-UV photolysis and hydroxyl radical oxidation, and exhibited the fastest degradation kinetics, achieving 99.6% (2.4-log) degradation with a UV fluence of 800 mJ/cm(2) and 5 mg/L hydrogen peroxide. Metaldehyde was poorly degraded by LP-UV photolysis while 97.7% (1.6-log) degradation was achieved with LP-UV/H2O2 treatment at the maximum tested UV fluence of 1000 mJ/cm(2) and 15 mg/L hydrogen peroxide. Clopyralid was hardly susceptible to LP-UV photolysis and exhibited the lowest degradation by LP-UV/H2O2 among the three pesticides. The second-order reaction rate constants for the reactions between the pesticides and OH-radicals were calculated applying a kinetic model for LP-UV/H2O2 treatment to be 3.6 × 10(8), 2.0 × 10(8) and 1.1 × 10(9) M(-1) s(-1) for metaldehyde, clopyralid and mecoprop, respectively. The main LP-UV photolysis reaction product from mecoprop was 2-(4-hydroxy-2-methylphenoxy) propanoic acid, while photo-oxidation by LP-UV/H2O2 treatment formed several oxidation products. The photo-oxidation of clopyralid involved either hydroxylation or dechlorination of the ring, while metaldehyde underwent hydroxylation and produced acetic acid as a major end product. Based on the findings, degradation pathways for the three pesticides by LP-UV/H2O2 treatment were proposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Production of methyl vinyl ketone and methacrolein via the hydroperoxyl pathway of isoprene oxidation

    Directory of Open Access Journals (Sweden)

    Y. J. Liu


    Full Text Available The photo-oxidation chemistry of isoprene (ISOP; C5H8 was studied in a continuous-flow chamber under conditions such that the reactions of the isoprene-derived peroxyl radicals (RO2 were dominated by the hydroperoxyl (HO2 pathway. A proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS with switchable H3O+ and NO+ reagent ions was used for product analysis. The products methyl vinyl ketone (MVK; C4H6O and methacrolein (MACR; C4H6O were differentiated using NO+ reagent ions. The MVK and MACR yields via the HO2 pathway were (3.8 ± 1.3% and (2.5 ± 0.9%, respectively, at +25 °C and 2 pathway implies concomitant production of hydroxyl ((6.3 ± 2.1% and hydroperoxyl ((6.3 ± 2.1% radicals, meaning a HOx recycling of (12.6 ± 4.2% given that HO2 was both a reactant and product. Other isoprene oxidation products, believed to be mostly organic hydroperoxides, also contributed to the ion intensity at the same mass-to-charge (m/z ratios as the MVK and MACR product ions for HO2-dominant conditions. These products were selectively removed from the gas phase by placement of a cold trap (−40 °C inline prior to the PTR-TOF-MS. When incorporated into regional and global chemical transport models, the yields of MVK and MACR and the concomitant HOx recycling reported in this study can improve the accuracy of the simulation of the HO2 reaction pathway of isoprene, which is believed to be the fate of approximately half of atmospherically produced isoprene-derived peroxy radicals on a global scale.

  16. Production of Modularised Product Systems

    DEFF Research Database (Denmark)

    Jacobsen, Peter


    Abstract: To day, more and more products are customized. Trends are not only to sell a product to the customer, but to sell a product system. The system can either be a combination of physical products or physical products together with some kind of service. Customers get in this way not a product...... but a solution. Modularisation is one tool used in designing the products. Designing and controlling a production system making customized products in an economical way is not an easy task. In order to fulfil the Lean and Agile manufacturing philosophies the production is often carried out in networks. Here...... the decoupling point has a central role. The scope for this article is therefore to analyse the possibilities for using modularisation in designing and controlling a production system. How will the development of modularised product systems influence the production system? In the paper, a case will be used...

  17. Product Customization

    DEFF Research Database (Denmark)

    Hvam, Lars; Mortensen, Niels Henrik; Riis, Jesper

    For the majority of industrial companies, customizing products and services is among the most critical means to deliver true customer value and achieve superior competitive advantage. The challenge is not to customize products and services in itself – but to do it in a profitable way...... from more than 40 product configuration projects in companies providing customer tailored products and services......., a reduction of the resources spent for the specification of customized products, and the possibility of optimizing the products according to customer demands. This book presents an operational procedure for the design of product configuration systems in industrial companies, based on the experience gained...

  18. Product Customization

    DEFF Research Database (Denmark)

    Hvam, Lars; Mortensen, Niels Henrik; Riis, Jesper

    For the majority of industrial companies, customizing products and services is among the most critical means to deliver true customer value and achieve superior competitive advantage. The challenge is not to customize products and services in itself – but to do it in a profitable way...... from more than 40 product configuration projects in companies providing customer tailored products and services........ The implementation of a product configuration system is among the most powerful ways of achieving this in practice, offering a reduction of the lead time for products and quotations, faster and more qualified responses to customer inquiries, fewer transfers of responsibility and fewer specification mistakes...

  19. Microwave Spectroscopic Study of the Atmospheric Oxidation Product m-TOLUIC Acid and its Monohydrate (United States)

    Al-Jabiri, Mohamad; Schnitzler, Elijah G.; Seifert, Nathan A.; Jäger, Wolfgang


    m-Toluic acid is a photo-oxidation product of m-xylene, a chemical byproduct of the oil and gas industry, and is a common component of secondary atmospheric aerosol. Organic acids, such as m-toluic acid, are also thought to play an important role in the initial steps of aerosol formation, which involves formation of hydrogen bonded clusters with molecular species, such as water, ammonia, and sulfuric acid. Somewhat surprisingly, the rotational spectrum of the m-toluic acid monomer has not been studied before. We have identified four stable conformers using ab initio calculations at the MP2/6-311++G(2df,2pd) level of theory. The two lowest energy conformers are rather close in energy and their rotational spectra were measured using a Balle-Flygare type microwave spectrometer. The structures and barriers to methyl internal rotation were determined. We have identified four isomers of the monohydrate of m-toluic acid using ab initio calculations. Measurements of the microwave spectra of the two lowest energy isomers are underway with a newly constructed chirped pulse microwave Fourier transform spectrometer in the frequency range from 2 to 6 GHz. The spectra and analyses will be presented.

  20. The Influence of Phosphor and Binder Chemistry on the Aging Characteristics of Remote Phosphor Products

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Lynn; Yaga, Robert; Lamvik, Michael; Mills, Karmann; Fletcher, B.


    The influence of phosphor and binder layer chemistries on the lumen maintenance and color stability of remote phosphor disks were examined using wet high-temperature operational lifetime testing (WHTOL). As part of the experimental matrix, two different correlated color temperature (CCT) values, 2700 K and 5000 K, were studied and each had a different binder chemistry. The 2700 K samples used a urethane binder whereas the 5000 K samples used an acrylate binder. Experimental conditions were chosen to enable study of the binder and phosphor chemistries and to minimize photo-oxidation of the polycarbonate substrate. Under the more severe WHTOL conditions of 85°C and 85% relative humidity (RH), absorption in the binder layer significantly reduced luminous flux and produced a blue color shift. The milder WHTOL conditions of 75°C and 75% RH, resulted in chemical changes in the binder layer that may alter its index of refraction. As a result, lumen maintenance remained high, but a slight yellow shift was found. The aging of remote phosphor products provides insights into the impact of materials on the performance of phosphors in an LED lighting system.

  1. Effects of Light and Temperature on Fatty Acid Production in Nannochloropsis Salina

    Directory of Open Access Journals (Sweden)

    Braden Crowe


    Full Text Available Accurate prediction of algal biofuel yield will require empirical determination of physiological responses to the environment, particularly light and temperature. One strain of interest, Nannochloropsis salina, was subjected to ranges of light intensity (5–850 μmol m−2 s−1 and temperature (13–40 °C and its exponential growth rate, total fatty acids (TFA and fatty acid composition were measured. The maximum acclimated growth rate was 1.3 day−1 at 23 °C and 250 μmol m−2 s−1. Fatty acids were detected by gas chromatography with flame ionization detection (GC-FID after transesterification to corresponding fatty acid methyl esters (FAMEs. A sharp increase in TFA containing elevated palmitic acid (C16:0 and palmitoleic acid (C16:1 during exponential growth at high light was observed, indicating likely triacylglycerol accumulation due to photo-oxidative stress. Lower light resulted in increases in the relative abundance of unsaturated fatty acids; in thin cultures, increases were observed in palmitoleic and eicosapentaenoic acids (C20:5ω3. As cultures aged and the effective light intensity per cell converged to very low levels, fatty acid profiles became more similar and there was a notable increase of oleic acid (C18:1ω9. The amount of unsaturated fatty acids was inversely proportional to temperature, demonstrating physiological adaptations to increase membrane fluidity. These data will improve prediction of fatty acid characteristics and yields relevant to biofuel production.

  2. Product Attachment

    NARCIS (Netherlands)

    Mugge, R.


    The topic of this doctoral research is the concept of product attachment for ordinary consumer durables. Product attachment is defined as the strength of the emotional bond a consumer experiences with a specific product. Specifically, the research investigated how this bond develops over time and

  3. Product Customization

    DEFF Research Database (Denmark)

    Hvam, Lars; Mortensen, Niels Henrik; Riis, Jesper

    For the majority of industrial companies, customizing products and services is among the most critical means to deliver true customer value and achieve superior competitive advantage. The challenge is not to customize products and services in itself – but to do it in a profitable way....... The implementation of a product configuration system is among the most powerful ways of achieving this in practice, offering a reduction of the lead time for products and quotations, faster and more qualified responses to customer inquiries, fewer transfers of responsibility and fewer specification mistakes......, a reduction of the resources spent for the specification of customized products, and the possibility of optimizing the products according to customer demands. This book presents an operational procedure for the design of product configuration systems in industrial companies, based on the experience gained...

  4. Product Customization

    DEFF Research Database (Denmark)

    Hvam, Lars; Mortensen, Niels Henrik; Riis, Jesper

    , a reduction of the resources spent for the specification of customized products, and the possibility of optimizing the products according to customer demands. This book presents an operational procedure for the design of product configuration systems in industrial companies, based on the experience gained......For the majority of industrial companies, customizing products and services is among the most critical means to deliver true customer value and achieve superior competitive advantage. The challenge is not to customize products and services in itself – but to do it in a profitable way....... The implementation of a product configuration system is among the most powerful ways of achieving this in practice, offering a reduction of the lead time for products and quotations, faster and more qualified responses to customer inquiries, fewer transfers of responsibility and fewer specification mistakes...

  5. Spectral effects in activation of the human immunodeficiency virus promoter by psoralens plus ultraviolet A treatment. (United States)

    Miller, S A; Beer, J Z; Strickland, A G; Zmudzka, B Z

    The effects of PUVA treatment on HIV promoter activation and cell killing in HIV cat/HeLa cells were studied using two UV sources, a UVASUN sunlamp and a UVAR Photoactivation Chamber. A 4 to 5 times higher dose of ultraviolet radiation was required from the UVASUN lamp than from the UVAR lamps: 1) to activate the HIV promoter in the presence of 0.1 or 1.0 microgram/ml 8-MOP and 2) to reduce cell survival to a level of 10%, in the presence of 0.1 or 1.0 microgram/ml 8-MOP. In addition, exposures performed with a fixed dose of 20 kJ/m2 at varying concentrations of 8-MOP, required a 4.7 times higher combined PUVA dose from the UVASUN lamp than from the UVAR lamps. Two possible sources of these differences were analyzed: (1) the presence of UVB + UVA2 (280-340 nm) in the radiation emitted by the UVAR, but not the UVASUN lamp, and its potential biological activity independent of 8-MOP, and (2) the difference in the overlap of the emission spectra of the two lamps with the absorption spectrum of 8-MOP. The area of overlap was higher for the UVAR lamp than for the UVASUN lamp by a factor of 4.6, which is close to the difference between these two lamps in induction of the HIV promoter and killing HeLa cells. This indicates that the effectiveness of a particular UVA source used in combination with 8-MOP can be predicted by its congruence to the absorption spectrum of the photosensitizing drug.

  6. UVB-activated psoralen reduces luminal narrowing after balloon dilation because of inhibition of constrictive remodeling

    NARCIS (Netherlands)

    Perrée, Jop; van Leeuwen, Ton G.; Velema, Evelyn; Smeets, Mirjam; de Kleijn, Dominique; Borst, Cornelius


    In this study we have explored the potential of PUVB (8-MOP + UVB) therapy for the reduction of luminal narrowing after arterial injury. In 15 rabbits, balloon dilation of iliac arteries was performed. In 20 arteries, dilation was combined with the delivery of pulsed ultraviolet light B (UVB)

  7. Determination of the minimal phototoxic dose and colorimetry in psoralen plus ultraviolet A radiation therapy. (United States)

    Kraemer, Cristine Kloeckner; Menegon, Dóris Baratz; Cestari, Tania Ferreira


    The use of an adequate initial dose of ultraviolet A (UVA) radiation for photochemotherapy is important to prevent burns secondary to overdosage, meanwhile avoiding a reduced clinical improvement and long-term risks secondary to underdosage. The ideal initial dose of UVA can be achieved based on the phototype and the minimal phototoxic dose (MPD). The objective measurement of constitutive skin color (colorimetry) is another method commonly used to quantify the erythematous skin reaction to ultraviolet radiation exposure. The aim of this study was to determine variations in MPD and constitutional skin color (coordinate L(*)) within different phototypes in order to establish the best initial dose of UVA radiation for photochemotherapy patients. Thirty-six patients with dermatological conditions and 13 healthy volunteers were divided into five groups according to phototype. Constitutional skin color of the infra-axillary area was assessed by colorimetry. The infra-axillary area was subsequently divided into twelve 1.5 cm(2) regions to determine the MPD; readings were performed 72 h after oral administration of 8-methoxypsoralen (MOP) followed by exposure of the demarcated regions to increasing doses of UVA. The majority of the participants were women (73.5%) and their mean age was 38.8 years. The MPD ranged from 4 to 12 J/cm(2) in phototypes II and III; from 10 to 18 J/cm(2) in type IV; from 12 to 24 J/cm(2) in type V and from 18 to 32 J/cm(2) in type VI. The analysis of colorimetric values (L(*) coordinate) and MPD values allowed the definition of three distinctive groups of individuals composed by phototypes II and III (group 1), types IV and V (group 2), and phototype VI (group 3). MPD and L(*) coordinate showed variation within the same phototype and superposition between adjacent phototypes. The values of the L(*) coordinate and the MPD lead to the definition of three distinct sensitivity groups: phototypes II and III, IV and V and type VI. Also, the MPD values bear a strong correlation to coordinate L(*) values. Mean MPD values described for each of the three major sensitivity groups were higher than the values commonly used in clinical settings for the different phototypes. Therefore, phototype alone is not a good parameter to define the initial UVA dose. MPD and colorimetry could be used in pre-treatment evaluation of patients who are to be submitted to photochemotherapy, in a non-invasive and more accurate way when compared with the classical phenotype clinical criteria.

  8. Secondary Plant Products Causing Photosensitization in Grazing Herbivores: Their Structure, Activity and Regulation

    Directory of Open Access Journals (Sweden)

    Jane C. Quinn


    Full Text Available Photosensitivity in animals is defined as a severe dermatitis that results from a heightened reactivity of skin cells and associated dermal tissues upon their exposure to sunlight, following ingestion or contact with UV reactive secondary plant products. Photosensitivity occurs in animal cells as a reaction that is mediated by a light absorbing molecule, specifically in this case a plant-produced metabolite that is heterocyclic or polyphenolic. In sensitive animals, this reaction is most severe in non-pigmented skin which has the least protection from UV or visible light exposure. Photosensitization in a biological system such as the epidermis is an oxidative or other chemical change in a molecule in response to light-induced excitation of endogenous or exogenously-delivered molecules within the tissue. Photo-oxidation can also occur in the plant itself, resulting in the generation of reactive oxygen species, free radical damage and eventual DNA degradation. Similar cellular changes occur in affected herbivores and are associated with an accumulation of photodynamic molecules in the affected dermal tissues or circulatory system of the herbivore. Recent advances in our ability to identify and detect secondary products at trace levels in the plant and surrounding environment, or in organisms that ingest plants, have provided additional evidence for the role of secondary metabolites in photosensitization of grazing herbivores. This review outlines the role of unique secondary products produced by higher plants in the animal photosensitization process, describes their chemistry and localization in the plant as well as impacts of the environment upon their production, discusses their direct and indirect effects on associated animal systems and presents several examples of well-characterized plant photosensitization in animal systems.

  9. Analysis of degradation products of PAH and PCP using electrospray ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Pavlovich, J.G.; Stringfellow, W.; Kazunga, Chikoma; Aitken, M.D.; Charles, M.J. [Univ. of North Carolina, Chapel Hill, NC (United States)


    Bioremediation is an important strategy for the clean-up of hazardous waste sites. In the past, assessing the efficacy of bioremediation techniques has involved monitoring the disappearance of the pollutant with minimal regard to the products formed via microbial degradation of the initial contaminant. Aromatic hydrocarbons in the environment are subject to oxidation by a variety of mechanisms including photooxidation, microbial degradation and metabolism by higher organisms. These processes result in an array of oxygenated products including hydroxylated aromatics, ketones, quinones, and acids. In many animals, metabolically activated PAH bind covalently to cellular species including sulfate, glucuronic acid, glutathione, as well as proteins and DNA. In some cases, the oxygenated species have been shown to be more highly toxic than the parent hydrocarbon. Measures directed at either controlling the migration of toxic microbial metabolites, or precluding their formation in the first place, can be developed intelligently if the chemical characteristics of the toxic can be determined. It is, therefore, desirable to characterize fully the degradation products present in environmental samples not only as a means of elucidating the degradation pathways, but in order to assess the full hazard represented by the contamination and the effectiveness of the clean-up protocols employed. Conventional GC/MS techniques often require extensive sample clean-up and fractionation, while the more polar metabolites are intractable to GC altogether. Since electrospray ionization is well suited to analysis of such polar nonvolatile compounds, as well as compatible with HPLC clean-up and separations, the authors are applying this technique to the analysis of polar degradation products of aromatic hydrocarbons including polycyclic aromatic hydrocarbons and chlorinated phenols.

  10. Product design - Molecules, devices, functional products, and formulated products

    DEFF Research Database (Denmark)

    Gani, Rafiqul; Ng, Ka M.


    Chemical product design is a multidisciplinary and diverse subject. This article provides an overview of product design while focusing on product conceptualization. Four product types are considered - molecular products, formulated products, devices and functional products. For molecular products......, computer-aided design tools are used to predict the physicochemical properties of single molecules and blends. For formulated products, an integrated experiment-modeling approach is used to generate the formula with the specified product attributes. For devices and functional products, conceptual product...

  11. Product Development (United States)

    McKim, Brian

    Product development is a vital piece of any industry, especially the food industry. It drives innovation, advances technology, and encourages growth. With the increasing concern for the safety of the food supply, product development has become an important step in the overall business process to provide consumers with food they feel safe eating. As a result, the product development profession has become an increasingly important and rewarding line of work.

  12. Generalized product


    Greco,Salvatore; Mesiar, Radko; Rindone, Fabio


    Aggregation functions on [0,1] with annihilator 0 can be seen as a generalized product on [0,1]. We study the generalized product on the bipolar scale [–1,1], stressing the axiomatic point of view. Based on newly introduced bipolar properties, such as the bipolar increasingness, bipolar unit element, bipolar idempotent element, several kinds of generalized bipolar product are introduced and studied. A special stress is put on bipolar semicopulas, bipolar quasi-copulas and bipolar copulas.

  13. Swine production. (United States)

    Plain, Ronald L; Lawrence, John D


    The US swine industry is large and growing. The quantity of pork desired by consumers of US pork is growing at the rate of 1.5%/y. New production systems and new technology have enabled production per sow to grow at a rate of 4% annually in recent years. Consequently, the number of sows in the United States is declining. Because productivity growth is outpacing demand growth, the deflated price of hogs and pork is declining. Hog production and prices continue to exhibit strong seasonal and cyclic patterns. Pork production is usually lowest in the summer and highest in the fall. Production and prices tend to follow 4-year patterns. The US swine industry continues to evolve toward fewer and larger producers who rely on contracts for both hog production and marketing. In 2000, over half of the hogs marketed were from approximately 156 firms marketing more than 50,000 head annually. These producers finished 60% of their production in contract facilities. Over 90% of their marketings were under contract or were owned by a packer. These producers expressed a high level of satisfaction with hog production. Both they and their contract growers were satisfied with production contracts. These large producers were satisfied with their marketing contracts and planned to continue them in the future. The hog industry has changed a great deal in the last decade. There is little reason to believe this rapid rate of change will not continue. This swine industry is highly competitive and profit driven. Profit margins are too small to allow producers the luxury of ignoring new technology and innovative production systems. Consequently, hog production will continue its rapid evolution from traditional agriculture to typical industry.

  14. A novel experimental approach for the determination of the photooxidative decay of semivolatile pesticides and POPs adsorbed on single levitated particles; Aufbau eines Messverfahrens zum photo-oxidativen Abbau von semivolatilen Pflanzenschutzmitteln und POPs an levitierten Einzelpartikeln

    Energy Technology Data Exchange (ETDEWEB)

    Ruehl, E.


    A novel experimental approach has been developed that permits to measure in the laboratory the atmospheric decay of low volatile, particle-bound compounds (pesticides, persistent organic pollutants (POP)) which react efficiently with OH-radicals in the atmosphere. The experimental approach makes use of trapped micro- and nanoparticles which are coated by monolayers of the low volatile compounds. Trapping is accomplished by storing the particles in an electrodynamic trap, which is surrounded by a controlled atmosphere. The temperature, pressure, humidity, and the chemical composition of the atmosphere can be adjusted to the atmospheric environment of interest. The particles can be exposed to reactive trace gases, such as OH radicals or ozone. The chemically induced changes of the adsorbates are time-resolved monitored by Raman spectroscopy. As a result, chemical processes, reaction products, as well as evaporation from the particle surface can be investigated. Alternatively, Fourier-transform infrared spectroscopy can be used for the detection of such time resolved processes. The experiments allow us to derive kinetic data of particle-bound low volatile compounds. We have constructed and characterized all devices and components that are required for this novel experimental approach. This included a suitable particle trap, sources of OH radicals, and the efficient detection of time-resolved Raman spectra of stored particles. The components were commissioned by using simple, but realistic test systems. Raman spectra of particle-bound pesticides were measured and first kinetic experiments were performed. The setup is now ready to use for systems of environmental interest. (orig.) [German] Es wurde ein neues experimentelles Verfahren zur quantitativen Bestimmung des Abbaus von partikelgebundenen gering volatilen Substanzen (Pflanzenschutzmittel, persistente organische Schadstoffe (POP)) durch OH-Radikale aufgebaut. Der experimentelle Ansatz nutzt beruehrungslos

  15. High-Resolution Mass Spectrometry and Molecular Characterization of Aqueous Photochemistry Products of Common Types of Secondary Organic Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Romonosky, Dian E.; Laskin, Alexander; Laskin, Julia; Nizkorodov, Sergey


    A significant fraction of atmospheric organic compounds is predominantly found in condensed phases, such as aerosol particles and cloud droplets. Many of these compounds are photolabile and can degrade through direct photolysis or indirect photooxidation processes on time scales that are comparable to the typical lifetimes of aqueous droplets (hours) and particles (days). This paper presents a systematic investigation of the molecular level composition and the extent of aqueous photochemical processing in different types of secondary organic aerosol (SOA) from biogenic and anthropogenic precursors including α-pinene, β-pinene, β-myrcene, d- limonene, α-humulene, 1,3,5-trimethylbenzene, and guaiacol, oxidized by ozone (to simulate a remote atmosphere) or by OH in the presence of NOx (to simulate an urban atmosphere). Chamber- and flow tube-generated SOA samples were collected, extracted in a methanol/water solution, and photolyzed for 1 h under identical irradiation conditions. In these experiments, the irradiation was equivalent to about 3-8 h of exposure to the sun in its zenith. The molecular level composition of the dissolved SOA was probed before and after photolysis with direct-infusion electrospray ionization high-resolution mass spectrometry (ESI-HR-MS). The mass spectra of unphotolyzed SOA generated by ozone oxidation of monoterpenes showed qualitatively similar features, and contained largely overlapping subsets of identified compounds. The mass spectra of OH/NOx generated SOA had more unique visual appearance, and indicated a lower extent of products overlap. Furthermore, the fraction of nitrogen containing species (organonitrates and nitroaromatics) was highly sensitive to the SOA precursor. These observations suggest that attribution of high-resolution mass spectra in field SOA samples to specific SOA precursors should be more straightforward under OH/NOx oxidation conditions compared to the ozone driven oxidation. Comparison of the SOA constituents

  16. Emissions of biogenic volatile organic compounds and subsequent photochemical production of secondary organic aerosol in mesocosm studies of temperate and tropical plant species (United States)

    Wyche, K. P.; Ryan, A. C.; Hewitt, C. N.; Alfarra, M. R.; McFiggans, G.; Carr, T.; Monks, P. S.; Smallbone, K. L.; Capes, G.; Hamilton, J. F.; Pugh, T. A. M.; MacKenzie, A. R.


    Silver birch (Betula pendula) and three Southeast Asian tropical plant species (Ficus cyathistipula, Ficus benjamina and Caryota millis) from the pantropical fig and palm genera were grown in a purpose-built and environment-controlled whole-tree chamber. The volatile organic compounds emitted from these trees were characterised and fed into a linked photochemical reaction chamber where they underwent photo-oxidation under a range of controlled conditions (relative humidity or RH ~65-89%, volatile organic compound-to-NOx or VOC / NOx ~3-9 and NOx ~2 ppbV). Both the gas phase and the aerosol phase of the reaction chamber were monitored in detail using a comprehensive suite of on-line and off-line chemical and physical measurement techniques. Silver birch was found to be a high monoterpene and sesquiterpene but low isoprene emitter, and its emissions were observed to produce measurable amounts of secondary organic aerosol (SOA) via both nucleation and condensation onto pre-existing seed aerosol (YSOA 26-39%). In contrast, all three tropical species were found to be high isoprene emitters with trace emissions of monoterpenes and sesquiterpenes. In tropical plant experiments without seed aerosol there was no measurable SOA nucleation, but aerosol mass was shown to increase when seed aerosol was present. Although principally isoprene emitting, the aerosol mass produced from tropical fig was mostly consistent (i.e. in 78 out of 120 aerosol mass calculations using plausible parameter sets of various precursor specific yields) with condensation of photo-oxidation products of the minor volatile organic compounds (VOCs) co-emitted; no significant aerosol yield from condensation of isoprene oxidation products was required in the interpretations of the experimental results. This finding is in line with previous reports of organic aerosol loadings consistent with production from minor biogenic VOCs co-emitted with isoprene in principally isoprene-emitting landscapes in Southeast

  17. Product Customization

    DEFF Research Database (Denmark)

    Hvam, Lars; Mortensen, Niels Henrik; Riis, Jesper

    . The implementation of a product configuration system is among the most powerful ways of achieving this in practice, offering a reduction of the lead time for products and quotations, faster and more qualified responses to customer inquiries, fewer transfers of responsibility and fewer specification mistakes...

  18. Product (RED)

    DEFF Research Database (Denmark)

    Ponte, Stefano


    of complex social, economic, and environmental processes. At the same time, we argue that there are important distinctions as well—labels and certifications are ultimately about improving the conditions of production, whereas RED is about accepting existing production and trade systems and donating......(PRODUCT)RED™ (hereafter RED) is a cobranding initiative launched in 2006 by the aid celebrity Bono to raise money from product sales to support The Global Fund to Fight AIDS, Tuberculosis and Malaria. In this paper we argue that RED is shifting the boundaries of ‘causumerism’ (shopping...... for a better world) by enrolling consumers in ways that do not rely on accurate knowledge of the products or specific understanding of the cause that The Global Fund engages but, instead, rely on a system of more general, affective affinity between the ‘aid celebrities’ who are behind RED (such as Bono...

  19. Primary productivity

    Digital Repository Service at National Institute of Oceanography (India)

    Verlecar, X.N.; Parulekar, A.H.

    nutrients and ample solar radiation frequently trigger phytoplankton blooms in coastal polynias during Antarctic summer. Energy transfer model for primary productivity has been used to derive potential exploitable fishery resources in the Indian Ocean....

  20. Marketplace Products (United States)

    U.S. Department of Health & Human Services — The Office of Enterprise Data and Analytics, within the Centers for Medicare aqnd Medicaid Services (CMS), has developed a set of information products and analytics...

  1. Production models

    DEFF Research Database (Denmark)

    Svensson, Carsten


    The Project is co-financed with Nilpeter A/S and investigates the industrialization of build to order production. Project content: - Enterprise engineering - Specification processes - Mass Customization/ Build To Order - Knowledge/information management - Configuration - Supply Chain Management...

  2. Product Classification (United States)

    U.S. Department of Health & Human Services — This database contains medical device names and associated information developed by the Center. It includes a three letter device product code and a Device Class...

  3. Measuring Productivity


    Del Gatto, Massimo; Di Liberto, Adriana; Petraglia, Carmelo


    Quantifying productivity is a conditio sine qua non for empirical analysis in a number of research fields. The identification of the measure that best fits with the specific goals of the analysis, as well as being data-driven, is currently complicated by the fact that an array of methodologies is available. This paper provides economic researchers with an up-to-date overview of issues and relevant solutions associated with this choice. Methods of productivity measurement are surveyed and clas...

  4. Quantification of Unidentified BVOC and their Oxidation Products in a forest canopy Using PTR-MS (United States)

    Kim, S.; Karl, T.; Guenther, A. B.; Greenberg, J.; Harley, P. C.; Orlando, J. J.; Tyndall, G. S.; Apel, E. C.; Rasmussen, R.


    A number of field, modeling and laboratory studies have reported that the presence of unidentified reactive organic volatile compounds (VOC) from biogenic sources potentially limit our understanding of photochemistry and secondary organic aerosol production. Discussion on the origin of unidentified VOC to date can be summarized in two sources-directly emitted biogenic VOC (BVOC) and oxidation products of identified BVOC. To quantitatively address the uncertainty, we will present the results of two different approaches using proton-transfer-reaction mass spectrometry (PTR-MS). First, analysis of mass discrimination corrected mass spectra with a wide mass range of 40 - 210 amu from branch enclosure and ambient samples provide us quantitative insight on the origin of unidentified VOC in the atmosphere. Second, we applied a recently developed OH reactivity measurement technique using PTR-MS by adopting the comparative reactivity method for branch enclosure samples to investigate unaccounted BVOC emission. Mass discrimination corrected mass spectral analysis of branch enclosure and ambient samples along with GC-MS measurements from the Manitou Forest observatory (Woodland Park, CO) in the summer of 2008 indicate that more than ~ 90 % of total counts in the spectra, obtained from branch enclosure samples can be explained by known compounds but only ~ 70% of total counts in the ambient spectra can be explained by known compounds. Branch enclosure OH reactivity measurements of four different tree species near the PROPHET tower (Pellston, MI) indicate that measured OH reactivity can be accounted for by major BVOC emissions such as isoprene and monoterpenes within the uncertainties of measurements. This series of exercises provides quantitative evaluation of our current understanding of BVOC emission and photo-oxidation.

  5. Photooxidation of anthracene under visible light with metallocarboxyphenylporphyrins

    Directory of Open Access Journals (Sweden)

    Carlos Enrique Díaz-Uribe


    Full Text Available En este trabajo sintetizamos metalocarboxifenilporfirinas (TcPP-M, M= Cu y Zn y la carboxifenilporfirina libre de metal (TcPPH y determinamos su eficiencia en la fotooxidación de antraceno bajo luz visible a través de la generación de oxígeno singulete ( 1 O 2 . La presencia de 1 O 2 fue evidenciada por Resonancia Paramagnética Electrónica (RPE, el cual el oxígeno singulete reacciona con la 2,2,6,6-tetrametil-4-piperidona-N (TEMP para producir el radical 2,2,6,6-tetrametil-4-piperidona-N-oxil (TEMPO. Los resultados catalíticos indican que la incorporación del metal en el anillo de la porfirina afecta su eficiencia sobre la oxidación del antraceno. La TcPPH mostró la eficiencia fotónica más alta en la conversión de antraceno (31 % en comparación con la TcPPZn (13 % y TcPPCu (9 %. Estos resultados pueden ser relacionados a la distorsión de la planaridad del anillo de porfirina. Finalmente se detectó la formación de antraquinona y oxoantrona como productos de oxidación in la reacción del antraceno con 1 O 2.

  6. Photo-oxidative damage in Cucumis leaves during chilling

    NARCIS (Netherlands)

    van Hasselt, Philip Robbert


    Low temperatures below the freezing point cause freezing injury to plants. The direct cause of freezing injury is the formation of ice in the plant tissue. Many thermophilic ("heat loving") plants, however, are already damaged at low temperatures above the freezing point. This is called chilling


    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...


    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  9. Photo-oxidative enhancement of polymeric molecular sieve membranes. (United States)

    Song, Qilei; Cao, Shuai; Zavala-Rivera, Paul; Lu, Li Ping; Li, Wei; Ji, Yan; Al-Muhtaseb, Shaheen A; Cheetham, Anthony K; Sivaniah, Easan


    High-performance membranes are attractive for molecular-level separations in industrial-scale chemical, energy and environmental processes. The next-generation membranes for these processes are based on molecular sieving materials to simultaneously achieve high throughput and selectivity. Membranes made from polymeric molecular sieves such as polymers of intrinsic microporosity (pore sizepolymer of intrinsic microporosity. The ultraviolet light field, localized to a near-surface domain, induces reactive ozone that collapses the microporous polymer framework. The rapid, near-surface densification results in asymmetric membranes with a superior selectivity in gas separation while maintaining an apparent permeability that is two orders of magnitude greater than commercially available polymeric membranes. The oxidative chain scission induced by ultraviolet irradiation also indicates the potential application of the polymer in photolithography technology.

  10. Product customization

    DEFF Research Database (Denmark)

    Lueg, Rainer


    analysis and Activity-based Costing help managers to better understand the different profitability of customized product lines. The rather open questions at the end of the case study allow for an adjustment to the level of knowledge of the students. Students will need to reflect on how a mechanical......This case study deals with the extension, customization, and profitability of two new product lines of a bicycle manufacturer. It can serve both as a discussion basis in class as well as an exam for advanced Master students in management, marketing, and ccounting. The case illustrates how variance...

  11. Characterization of Photochemical Processes for H2 Production by CdS Nanorod-[FeFe] Hydrogenase Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Brown, K. A.; Wilker, M. B.; Boehm, M.; Dukovic, G.; King, P. W.


    We have developed complexes of CdS nanorods capped with 3-mercaptopropionic acid (MPA) and Clostridium acetobutylicum [FeFe]-hydrogenase I (CaI) that photocatalyze reduction of H{sup +} to H{sub 2} at a CaI turnover frequency of 380-900 s{sup -1} and photon conversion efficiencies of up to 20% under illumination at 405 nm. In this paper, we focus on the compositional and mechanistic aspects of CdS:CaI complexes that control the photochemical conversion of solar energy into H{sub 2}. Self-assembly of CdS with CaI was driven by electrostatics, demonstrated as the inhibition of ferredoxin-mediated H{sub 2} evolution by CaI. Production of H{sub 2} by CdS:CaI was observed only under illumination and only in the presence of a sacrificial donor. We explored the effects of the CdS:CaI molar ratio, sacrificial donor concentration, and light intensity on photocatalytic H{sub 2} production, which were interpreted on the basis of contributions to electron transfer, hole transfer, or rate of photon absorption, respectively. Each parameter was found to have pronounced effects on the CdS:CaI photocatalytic activity. Specifically, we found that under 405 nm light at an intensity equivalent to total AM 1.5 solar flux, H{sub 2} production was limited by the rate of photon absorption ({approx}1 ms{sup -1}) and not by the turnover of CaI. Complexes were capable of H{sub 2} production for up to 4 h with a total turnover number of 106 before photocatalytic activity was lost. This loss correlated with inactivation of CaI, resulting from the photo-oxidation of the CdS capping ligand MPA.

  12. Characterization of photochemical processes for H2 production by CdS nanorod-[FeFe] hydrogenase complexes. (United States)

    Brown, Katherine A; Wilker, Molly B; Boehm, Marko; Dukovic, Gordana; King, Paul W


    We have developed complexes of CdS nanorods capped with 3-mercaptopropionic acid (MPA) and Clostridium acetobutylicum [FeFe]-hydrogenase I (CaI) that photocatalyze reduction of H(+) to H(2) at a CaI turnover frequency of 380-900 s(-1) and photon conversion efficiencies of up to 20% under illumination at 405 nm. In this paper, we focus on the compositional and mechanistic aspects of CdS:CaI complexes that control the photochemical conversion of solar energy into H(2). Self-assembly of CdS with CaI was driven by electrostatics, demonstrated as the inhibition of ferredoxin-mediated H(2) evolution by CaI. Production of H(2) by CdS:CaI was observed only under illumination and only in the presence of a sacrificial donor. We explored the effects of the CdS:CaI molar ratio, sacrificial donor concentration, and light intensity on photocatalytic H(2) production, which were interpreted on the basis of contributions to electron transfer, hole transfer, or rate of photon absorption, respectively. Each parameter was found to have pronounced effects on the CdS:CaI photocatalytic activity. Specifically, we found that under 405 nm light at an intensity equivalent to total AM 1.5 solar flux, H(2) production was limited by the rate of photon absorption (~1 ms(-1)) and not by the turnover of CaI. Complexes were capable of H(2) production for up to 4 h with a total turnover number of 10(6) before photocatalytic activity was lost. This loss correlated with inactivation of CaI, resulting from the photo-oxidation of the CdS capping ligand MPA.

  13. Cellulase Production

    African Journals Online (AJOL)

    Microbiol. Technol.2:92-102. Smiths, J.P.; Rinzema, A.; Tramper, J., Van, H.M. and Knol, W. 1996. Solid-state fermentation of wheat bran by. Trichoderma reesei QM9414: Substrate composition, changes, C-balance, enzyme production, growth and kinetics. Appl. Microbiol. Biotechnol.46:489-496. Solomon, B.O.; Amigun, B.; ...

  14. Product stewardship in wollastonite production. (United States)

    Maxim, L Daniel; Niebo, Ron; Larosa, Salvatore; Johnston, Brad; Allison, Kimberly; McConnell, E E


    In July 2002, NYCO Minerals, Inc., discovered a heretofore unknown contaminant in its wollastonite ore. The contaminant was first believed to be tremolite asbestos. Immediate efforts were made to eliminate this material. Additional studies were initiated to fully characterize the contaminant and its distribution in the ore body. Subsequent study by NYCO and their consultants led to the identification of the contaminant as a transition material (TM) intermediate between tremolite and talc. In vitro dissolution rate measurements indicated that the TM dissolved much more rapidly than tremolite asbestos. This article provides background information on wollastonite mineralogy and NYCO's product stewardship program (PSP). At present, NYCO Minerals uses selective mining to control the trace levels of TM in the ore and finished product verified by periodic monitoring of workplace air and finished product.

  15. Product Configuration Systems and Productivity

    DEFF Research Database (Denmark)

    Pedersen, Jørgen Lindgaard; Edwards, Kasper


    Twelve companies have been interviewed with the purpose to get information about technical, economic and organisational matters in respect of Product Configuration Systems (PCS).Combinations of qualitative interviews and quantitative scoring have been used in ranking expected and realized results...

  16. Lepton production

    CERN Multimedia


    This experiment aims to settle open questions in the hadronic production of electrons, muons and neutrinos. Prominent among these are $e/\\mu$ universality, the contribution of charm decay to lepton pair production, and the "anomalous" low mass pairs.\\\\ The experimental design aims to optimize the combination of:\\\\- electron identification\\\\ - muon identification \\\\ - missing energy measurement for neutrinos \\\\ - vertex identification (for $\\tau \\simeq \\tau_{charm}$). \\\\ \\\\ The major components of the apparatus are shown in the figure. In the vertex region a proton beam of transverse size $\\simeq 50 \\mu$ impinges on a beryllium target of diameter $50 \\mu$, and high precision tracking in the vertex region is achieved by silicon strip detectors. Charged particle momenta are measured using a dipole magnet and high resolution drift chambers. Electrons are identified by the combination of the transition radiation detector and the finely segmented front section of the Uranium/Liquid Argon calorimeter. Essentially t...

  17. Tequila production. (United States)

    Cedeño, M


    Tequila is obtained from the distillation of fermented juice of agave plant, Agave tequilana, to which up to 49% (w/v) of an adjunct sugar, mainly from cane or corn, could be added. Agave plants require from 8 to 12 years to mature and during all this time cleaning, pest control, and slacken of land are required to produce an initial raw material with the appropriate chemical composition for tequila production. Production process comprises four steps: cooking to hydrolyze inulin into fructose, milling to extract the sugars, fermentation with a strain of Saccharomyces cerevisiae to convert the sugars into ethanol and organoleptic compounds, and, finally, a two-step distillation process. Maturation, if needed, is carried out in white oak barrels to obtain rested or aged tequila in 2 or 12 months, respectively.

  18. Diboson production

    Directory of Open Access Journals (Sweden)

    Evans D.L.


    Full Text Available Measurements of diboson production cross sections in pp collisions at the LHC at a centre of mass energy √s = 7 and 8 TeV, and in pp̅ collisions at the Tevatron at √s = 1.96 TeV are reviewed and compared with standard model predictions. Limits on charged and neutral anomalous triple gauge couplings extracted from the selected diboson event samples are also compared.

  19. Firm productivity


    la Cour, Lisbeth; Ionascu, Delia


    It has been argued that the effect of competition on a company’s incentive to innovate and to reduce managerial slack depends on the initial level of efficiency. For example, while firms close to the technology frontier invest more in innovation if competition increases, backward firms reduce innovation. On a panel data of Czech companies, for the years 1993-2005, we empirically assess the impact of increased competition on firm productivity and the importance of the initial firm efficiency l...

  20. production lines

    Directory of Open Access Journals (Sweden)

    Jingshan Li


    Full Text Available In this work, serial production lines with finished goods buffers operating in the pull regime are considered. The machines are assumed to obey Bernoulli reliability model. The problem of satisfying customers demand is addressed. The level of demand satisfaction is quantified by the due-time performance (DTP, which is defined as the probability to ship to the customer a required number of parts during a fixed time interval. Within this scenario, the definitions of DTP bottlenecks are introduced and a method for their identification is developed.

  1. Extensive burns caused by the abusive use of photosensitizing agents. (United States)

    Braye, F; Latarjet, J; Foyatier, J L; Comparin, J P; Tranchand, P; Boucaud, C


    Psoralens are photosensitizing agents used in dermatology as reinforcements in psoralen ultraviolet A-range therapy. We report observations of 14 young women hospitalized for severe burns caused by abusive use of psoralens. The burns were of superficial and deep second-degree depth and covered more than 76% of the body surface on average. All patients needed fluid resuscitation. Hospital stay was 11 days on average. Healing was obtained without skin grafting in all cases. Among the six patients who responded to the mailed questionnaire, negative effects are now present in all patients as inflammatory peaks. Two patients have esthetic sequelae such as dyschromia and scars. The misuse of photosensitizing agents poses many problems. These accidents are very expensive. The largeness of the burned surface can involve a fatal prognosis. And finally, one can suspect that a much larger portion of the population regularly uses these products without any serious accident. In this case carcinogenesis can be expected.

  2. Innovation in Product Development

    DEFF Research Database (Denmark)

    McAloone, Tim C.; Restrepo-Giraldo, John Dairo


    The course on Innovation in Product Development attempts to identify and understand the nature of innovation and product development and their important factors. The course takes both a theoretical and a practical approach and employs a mix of lectures, project work and group discussion. Format...... insight. Course content The following aspects of innovation in product development are considered: - Humans and products - Needs and products - Product life - Teams creating products - Products creating business - Product development models - Organising product development - Product development tools...

  3. Oil Oxidative Transformation Products Revealed by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (United States)

    Rodgers, R. P.; Podgorski, D. C.; Ray, P. Z.; McKenna, A. M.; Chen, H.; Clingenpeel, A. C.; Rowland, S. M.


    The chemical transformation of petrogenic carbon in the environment yields an incredible complex mixture of products that can dramatically alter native petroleum chemical functionalities. The changes affect toxicity, solubility, tendency for emulsion/mousse formation, aggregation, and ultimately, bioavailability. However, these changes are difficult to track at the molecular level, as the qualitative understanding of the (predominately) oxidative weathering is hampered by the immense complexity of the unaltered oil and multiplicative increase in complexity post-oxidation. Simply, a large fraction of unaltered oil that was initially accessible by GC-methods is chemically transformed into species that preclude GC based analyses. Thus, the fate of petrogenic transformation products and their potential to form undesirable future contaminants remain unknown. However, recent advances in analytical methodology and instrumentation now allow a molecular-level insight into these complex systems. Combined with the comprehensive analysis of the unaltered well oil, detailed compositional analysis of oil-impacted sites along the Gulf of Mexico coast over the past 4 years has revealed tens-of-thousands of previously unidentified, unique, biotic and abiotic transformation products that persist. Here, we highlight efforts to characterize oxidized transformation products, identify their oxygen functionalities, and demonstrate how they affect physical/chemical behavior of weathered oil. Temporal analysis of field samples reveal compositional changes of weathered oil as a function of oil contamination levels. Once determined, abiotic microcosm results are compared to the field samples to assess how well they account for observed changes in field samples. Finally, chromatographic separation of unaltered well oil (and surrogate) into structurally defined fractions (saturate, 1-ring, 2-ring, 3-ring, 4-ring and 5+ring aromatics / polars), followed by subsequent photo-oxidation of each

  4. Micro Products - Product Development and Design

    DEFF Research Database (Denmark)

    Hansen, Hans Nørgaard


    of the electronics industry to create still smaller chips with still larger capacity. Therefore the manufacturing technologies connected with micro/nano products in silicon are relatively highly developed compared to the technologies used for manufacturing micro products in metals, polymers and ceramics. For all...... technologies, however, it is a continuously increasing challenge to create the operational basis for an industrial production of micro products. As the products through product development processes are made applicable to a large number of customers, the pressure in regard to developing production technologies...... that make it possible to produce the products at a reasonable price and in large numbers is growing....

  5. Tobacco Products Production and Operations Reports (United States)

    Department of the Treasury — Monthly statistical reports on tobacco products production and operations. Data for Tobacco Statistical Release is derived directly from the Report – Manufacturer of...

  6. SaferProducts API (United States)

    US Consumer Product Safety Commission — On March 11, 2011, the U.S. Consumer Product Safety Commission launched This site hosts the agency's new Publicly Available Consumer Product...

  7. The structuring of products and product programmes

    DEFF Research Database (Denmark)

    Andreasen, Mogens myrup; Hansen, Claus thorp; Mortensen, Niels henrik


    Structure means the way in which things are build up. A composed product does not exhibit one structure, but hides in its structure of parts several different structuring principles, which fit the product for production and service and make it a member of a product programme, where other family....... This article has two substantial contributions to the theory of technical systems: Explaining the superimposed structures in products and proposing a modelling framework for support of structuring to be implemented in design support systems....

  8. Extracting Product Features from Chinese Product Reviews


    Yahui Xi


    With the great development of e-commerce, the number of product reviews grows rapidly on the e-commerce websites. Review mining has recently received a lot of attention, which aims to discover the valuable information from the massive product reviews. Product feature extraction is one of the basic tasks of product review mining. Its effectiveness can influence significantly the performance of subsequent jobs. Double Propagation is a state-of-the-art technique in product feature extraction. In...

  9. Product Service Systems

    DEFF Research Database (Denmark)

    Departing from Product Development models based on physical artefacts. Moving towards integrated Product Development and System Operations models suited Product/Service-systems......Departing from Product Development models based on physical artefacts. Moving towards integrated Product Development and System Operations models suited Product/Service-systems...

  10. RBOH1-dependent H2O2 production and subsequent activation of MPK1/2 play an important role in acclimation-induced cross-tolerance in tomato. (United States)

    Zhou, Jie; Xia, Xiao-Jian; Zhou, Yan-Hong; Shi, Kai; Chen, Zhixiang; Yu, Jing-Quan


    H2O2 and mitogen-activated protein kinase (MAPK) cascades play important functions in plant stress responses, but their roles in acclimation response remain unclear. This study examined the functions of H2O2 and MPK1/2 in acclimation-induced cross-tolerance in tomato plants. Mild cold, paraquat, and drought as acclimation stimuli enhanced tolerance to more severe subsequent chilling, photooxidative, and drought stresses. Acclimation-induced cross-tolerance was associated with increased transcript levels of RBOH1 and stress- and defence-related genes, elevated apoplastic H2O2 accumulation, increased activity of NADPH oxidase and antioxidant enzymes, reduced glutathione redox state, and activation of MPK1/2 in tomato. Virus-induced gene silencing of RBOH1, MPK1, and MPK2 or MPK1/2 all compromised acclimation-induced cross-tolerance and associated stress responses. Taken together, these results strongly suggest that acclimation-induced cross-tolerance is largely attributed to RBOH1-dependent H2O2 production at the apoplast, which may subsequently activate MPK1/2 to induce stress responses.

  11. Product Family Assessment

    DEFF Research Database (Denmark)

    Kvist, Morten

    product this will in time lead to a patchwork of product variants, features, parts, and process technologies – i.e. a product family so complex that it becomes a burden in the companies’ daily operation. As a consequence there has been an increase in the number of companies that are beginning to change...... their focus from single products to entire product families and try to incorporate the development of product variety into a future product family. The key is to create fit between the product design and production setup. The challenge of understanding this fit and modelling dispositional relations between...... the existing product design and the production setup with an eye re-design the products and/or the production setup is the main topic for this research project. This research contributes with a visual modelling formalism which has its basis in the Product Family Master Plan (PFMP) presented in the work of Ulf...

  12. Biological production of products from waste gases (United States)

    Gaddy, James L.


    A method and apparatus are designed for converting waste gases from industrial processes such as oil refining, and carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various products, such as organic acids, alcohols, hydrogen, single cell protein, and salts of organic acids by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified.

  13. Interplay between human high mobility group protein 1 and replication protein A on psoralen-cross-linked DNA

    DEFF Research Database (Denmark)

    Reddy, Madhava C; Christensen, Jesper; Vasquez, Karen M


    Human high mobility group box (HMGB) 1 and -2 proteins are highly conserved and abundant chromosomal proteins that regulate chromatin structure and DNA metabolism. HMGB proteins bind preferentially to DNA that is bent or underwound and to DNA damaged by agents such as cisplatin, UVC radiation...

  14. Productivity and Performance Measurement

    DEFF Research Database (Denmark)

    Hald, Kim Sundtoft; Spring, Martin

    This study explores conceptually how performance measurement as discussed in the literature, enables or constrains the ability to manage and improve productivity. It uses an inter-disciplinary literature review to identify five areas of concern relating productivity accounting to the ability...... to improve productivity: “Productivity representation”; “productivity incentives”, “productivity intervention”; “productivity trade-off or synergy” and “productivity strategy and context”. The paper discusses these areas of concern and expands our knowledge of how productivity and performance measurement...

  15. Heavy Flavour Production


    Nason, P; Ridolfi, G.; Frixione, S.


    We review the status of heavy flavour production in QCD. Comparison of experimental and theoretical results for top and bottom production are given. Selected topics in charm production are also discussed.


    Directory of Open Access Journals (Sweden)

    L. V. Golubeva


    Full Text Available Cottage cheese products holds a significant place among the dairy and milk-containing products. The range of products includes cheese: cheese, pastes, creams, cakes, etc. Such diversity can be attributed to their popularity among the population and benefit brought by the body from regular use. Curd protein is much better and easier to digest by the body than protein fish, meat or milk. Rich curd products lysine and methionine. Minerals contained in cheese products have a positive effect on bone formation and structure of tissues. The composition of curd products, in addition to cheese and dairy ingredients may include non-dairy ingredients origin. Today, for the production of cheese products use the most advanced technologies to further enrich its structure and significantly improve the nutritional value. Pine nut is widely used in the manufacture of many dairy products. But, in most cases, the production of dairy products as a filler used pine nut cake, which deprives the finished product valuable cedar oil. The authors proposed a technology for producing curd product with the addition of pine nuts and honey (pine nuts and fructose. Compatible with cream cheese filling insertion determined sensory organoleptic point scale. he optimum dosage of components: pine nuts – 5 %, honey – 10 % fructose – 7 %. Technological process of cottage cheese product is different from the traditional operations training components and their introduction into the finished cheese. Identify indicators of quality of the new product. Production of curd products thus expanding the range of dairy products functional orientation.

  17. PDT (Product Data Technology), Production and Society

    DEFF Research Database (Denmark)

    Vesterager, Johan


    Information and communication technology (ICT) constitute a genuine technical revolution by enabling a dynamic and flexible support or automation of knowledge and information work. Bearing in mind that products are frozen knowledge, ICT as known will change the way we produce products dramatically....... The use of ICT in engineering of products constitutes product data technology (PDT).This paper presents a a basic platform for an understanding the ongoing revolution with focus on the PDT-area taking outset in the fundamental elements of knowledge and information work: creation, transformation...

  18. Animal Production Research Advances

    African Journals Online (AJOL)

    Animal Production Research Advances is a peer-review journal established expressly to promote the production of all animal species utilized as food. The journal has an international scope and is intended for professionals in animal production and related sciences. We solicit contributions from animal production and ...

  19. Intelligent products : A survey

    NARCIS (Netherlands)

    Meyer, G.G.; Främling, K.; Holmström, J.

    This paper presents an overview of the field of Intelligent Products. As Intelligent Products have many facets, this paper is mainly focused on the concept behind Intelligent Products, the technical foundations, and the achievable practical goals of Intelligent Products. A novel classification of

  20. Making Product Customization Profitable

    DEFF Research Database (Denmark)

    Mortensen, Niels Henrik; Hvam, Lars; Haug, Anders


    The main result presented in this paper is the Framework for Product Family Master Plan. This framework supports the identification of a product architecture for companies that customize products and services. The framework has five coherent aspects, the market, product assortment, supply...

  1. Designing Product Families

    DEFF Research Database (Denmark)

    Pedersen, Per Erik Elgård; Miller, Thomas Dedenroth


    Manufacturing companies that operate with products aimed at different market segments and applications are experiencing an increasing demand from customers who expect products to be tailored to their exact needs rather than accepting general products based on average customer needs. This trend ha......: Variety, Design Principles, and Product Maturity.......Manufacturing companies that operate with products aimed at different market segments and applications are experiencing an increasing demand from customers who expect products to be tailored to their exact needs rather than accepting general products based on average customer needs. This trend has...... led to a new business paradigm, "mass customization", where companies strive to provide highly customized products while still maintaining the efficiency of the classical mass production enterprise. One of the key factors in mass customization has been efficient use of product platforms...

  2. Production monitoring and control with intelligent products

    NARCIS (Netherlands)

    Meyer, G.G.; Szirbik, N.; Wortmann, J.C.


    Advances in production planning and control in recent decades have focused on increasing the sophistication of the planning function. For good reasons, these advances have led to the centralisation of the planning function in production. However, the sophistication of the planning function should be


    Directory of Open Access Journals (Sweden)



    Full Text Available In this paper we conceptually discussed the brands’ role in the society, the dimensions of branding and the relationship between the brand and the products. We adhere to the main ideas expressed in the literature, that the brand is more than a product. However the product is needed to render the brand tangible. The product is the magic box that delivers the brand experience. Without the product, the brand meaning would have difficulties in attracting customers. More studies are needed to investigate the brand-product relationship.

  4. Emulsified Water Products

    Directory of Open Access Journals (Sweden)

    Elif Tuğçe AKSUN


    Full Text Available Seafood is very important depending on having high protein rate and easily digestibility by human, for supply to an important part of animal protein needed. Determining the quality of emulsion-type products, emulsion stability, viscosity and gel strength properties are very important. In the production of products specified in this property emulsion; the main protein ratio and properties of raw material used while you; emulsion pH, temperature, ionic violence, mixing speed, type of fat and additives that are used as well. Previous studies show that particularly of products resulting from water emulsified chicken and goat meat emulsified product obtained from a high capacity of emulsified and compared to cattle and sheep meat is close to specifications, preparation of emulsified type products may be appropriate for the use of fish meat. Another quality parameter in the emulsified meat products, viscosity depends on the amount of meat used in direct proportion with the texture. Fish meat animals in connective tissue connective tissue in meat other butchers to rate ratio is quite low. In this respect, the fish meat produced using emulsified products viscosity according to products prepared using other meat products is quite low. Fish meat produced using emulsified fish sausage products based on surimi, sausage and fish pate fish varieties classed emulsion type products. In this review the different types of seafood using emulsified meat product.

  5. Consumer Product Category Database (United States)

    U.S. Environmental Protection Agency — The Chemical and Product Categories database (CPCat) catalogs the use of over 40,000 chemicals and their presence in different consumer products. The chemical use...

  6. Pesticide Product Label System (United States)

    U.S. Environmental Protection Agency — The Pesticide Product Label System (PPLS) provides a collection of pesticide product labels (Adobe PDF format) that have been approved by EPA under Section 3 of the...

  7. Urinary incontinence products (United States)

    ... able to help you find products. Call toll-free at 1-800-BLADDER or visit the website: . You can buy their Resource Guide that lists products and services along with mail order companies.

  8. Increasing productivity: Another approach

    Energy Technology Data Exchange (ETDEWEB)

    Norton, F.J.


    An engineering information (EI) and information technology (IT) organization that must improve its productivity should work to further its business goals. This paper explores a comprehensive model for increasing EI/IT productivity by supporting organizational objectives.

  9. Transformer Industry Productivity Slows. (United States)

    Otto, Phyllis Flohr


    Annual productivity increases averaged 2.4 percent during 1963-79, slowing since 1972 to 1.5 percent; computer-assisted design and product standardization aided growth in output per employee-hour. (Author)

  10. Advances in production technology

    CERN Document Server


    This edited volume contains the selected papers presented at the scientific board meeting of the German Cluster of Excellence on “Integrative Production Technology for High-Wage Countries”,  held in November 2014. The topical structure of the book is clustered in six sessions: Integrative Production Technology, Individualised Production, Virtual Production Systems, Integrated Technologies, Self-Optimising Production Systems and Human Factors in Production Technology. The Aachen perspective on a holistic theory of production is complemented by conference papers from external leading researchers in the fields of production, materials science and bordering disciplines. The target audience primarily comprises research experts and practitioners in the field but the book may also be beneficial for graduate students.

  11. MEET ISOLDE - Target Production

    CERN Multimedia


    MEET ISOLDE - Target Production. Everything at ISOLDE starts with a target and the target production team realise on more then 50 years of experience to build and develop new targets for ISOLDE’s wide physics program.

  12. Animal Product Safety Information (United States)

    ... Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products Animal & Veterinary Home Animal & Veterinary Safety & Health Product Safety ... for more information. How to report when your animal has a bad reaction to a drug the ...

  13. The new productivity challenge. (United States)

    Drucker, P F


    "The single greatest challenge facing managers in the developed countries of the world is to raise the productivity of knowledge and service workers," writes Peter F. Drucker in "The New Productivity Challenge." Productivity, says Drucker, ultimately defeated Karl Marx; it gave common laborers the chance to earn the wages of skilled workers. Now five distinct steps will raise the productivity of knowledge and service workers--and not only stimulate new economic growth but also defuse rising social tensions.

  14. Southern pulpwood production, 2006 (United States)

    Tony G. Johnson; Carolyn D. Steppleton


    The South's production of pulpwood increased from 64.0 million cords in 2005 to 64.7 million cords in 2006. Roundwood production increased 123,300 cords to 46.3 million cords and accounted for 72 percent of the total pulpwood production. The use of wood residue increased 3 percent to 18.3 million cords. Alabama led the South in total production at 10.5 million...

  15. Nordic Noir Production Values

    DEFF Research Database (Denmark)

    Waade, Anne Marit; Jensen, Pia Majbritt


    In this article the authors argue that Nordic noir constitutes a set of production values utilised and conceptualised to make Danish television series attractive in the international market. The idea of production values is embedded into a media industrial context where market principles of target...... by relating the specific Nordic noir production values present in the two series to changing conditions in Danish television drama production, in particular the internationalisation of DR’s Drama Division....

  16. Virtual product development


    Buisan Ferrer, Josep


    Evaluating the functionality, security, quality, etc. of a product can be long and difficult process. Prototypes and real tests are determinant tools, however their exhaustive use during the product development process can increase the price of the process and delay the availability of the product on the market. The alternative is to combine 3D design tools with other advanced simulation tools.

  17. Strangeness Production at COSY


    Hinterberger, Frank; Machner, Hartmut; Siudak, Regina


    The paper gives an overview of strangeness-production experiments at the Cooler Synchrotron COSY. Results on kaon-pair and phi meson production in pp, pd and dd collisions, hyperon-production experiments and Lambda p final-state interaction studies are presented.

  18. Age, Wage and Productivity

    NARCIS (Netherlands)

    van Ours, J.C.; Stoeldraijer, L.


    Previous empirical studies on the effect of age on productivity and wages find contradicting results. Some studies find that if workers grow older there is an increasing gap between productivity and wages, i.e. wages increase with age while productivity does not or does not increase at the same

  19. Fermentative production of isobutene

    NARCIS (Netherlands)

    Van Leeuwen, B.N.M.; Van der Wulp, A.M.; Duijnstee, I.; Van Maris, A.J.A.; Straathof, A.J.J.


    Isobutene (2-methylpropene) is one of those chemicals for which bio-based production might replace the petrochemical production in the future. Currently, more than 10 million metric tons of isobutene are produced on a yearly basis. Even though bio-based production might also be achieved through

  20. Improving pension product design

    DEFF Research Database (Denmark)

    Konicz, Agnieszka Karolina; Mulvey, John M.


    Pension products characterized by linking an individual's savings directly to market returns represent the most popular, growing pension domain globally. These products are widely sold in contribution-defined pension schemes, labor market pensions, and individual schemes. However, available...... of an optimal pension product design, we present the operations research methods, which have potential to stimulate new thinking and add to actuarial practice....

  1. Pomegranate production and marketing (United States)

    This book is relatively short, with 134 pages, 15 chapters, 52 figures, and 20 tables. It ranges from cultivar descriptions, production, biotic and abiotic challenges to production, to postharvest, aril and juice production, health benefits, and international trade. It contains great information and...

  2. Star Products and Applications


    Iida, Mari; Yoshioka, Akira


    Star products parametrized by complex matrices are defined. Especially commutative associative star products are treated, and star exponentials with respect to these star products are considered. Jacobi's theta functions are given as infinite sums of star exponentials. As application, several concrete identities are obtained by properties of the star exponentials.

  3. Augmented Cellular Meat Production

    DEFF Research Database (Denmark)

    Rehm, Matthias; Philipsen, Mark Philip; Andersen, Rasmus Skovgaard


    of robots that can adapt to the high variation in both products and the interaction with humans. The project contains three labor-intensive cases. The first case, sensing assistance, will visualize information about the product to the operator. The second, robot assistant, will present the product optimally...

  4. Coal production 1989

    Energy Technology Data Exchange (ETDEWEB)


    Coal Production 1989 provides comprehensive information about US coal production, the number of mines, prices, productivity, employment, reserves, and stocks to a wide audience including Congress, federal and state agencies, the coal industry, and the general public. 7 figs., 43 tabs.

  5. Scenario based product design

    NARCIS (Netherlands)

    Tideman, M.


    Creating good products is not an easy thing to do. There are usually many different people who have an interest in the product. People such as the user, of course, but also marketing managers, production engineers, maintenance workers, recycling specialists, and government representatives, just to

  6. Upgrading Uncompetitive Products Economically

    DEFF Research Database (Denmark)

    Lu, Hua; Jensen, C.S.


    The skyline of a multidimensional point set consists of the points that are not dominated by other points. In a scenario where product features are represented by multidimensional points, the skyline points may be viewed as representing competitive products. A product provider may wish to upgrade...

  7. Product Structuring, an overview

    DEFF Research Database (Denmark)

    Tichem, Marcel; Storm, Ton; Andreasen, Mogens Myrup


    This paper presents the highlights of two WDK Workshops on Product Structuring. Product structuring plays an important role in creating products which have good functional and life-cycle related properties, in design process management, and in several other company functions like production control.......In the paper, the field of product structuring is defined and broken down into topics. For each of the topics, results of research are presented. Issues for further research are identified. The references in the paper refer to papers in the proceedings of the workshops....

  8. Citric acid production. (United States)

    Berovic, Marin; Legisa, Matic


    Citric acid is a commodity chemical produced and consumed throughout The World. It is used mainly in the food and beverage industry, primarily as an acidulant. Although it is one of the oldest industrial fermentations, its World production is still in rapid increasing. Global production of citric acid in 2007 was over 1.6 million tones. Biochemistry of citric acid fermentation, various microbial strains, as well as various substrates, technological processes and product recovery are presented. World production and economics aspects of this strategically product of bulk biotechnology are discussed.

  9. Evolving production network structures

    DEFF Research Database (Denmark)

    Grunow, Martin; Gunther, H.O.; Burdenik, H.


    When deciding about future production network configurations, the current structures have to be taken into account. Further, core issues such as the maturity of the products and the capacity requirements for test runs and ramp-ups must be incorporated. Our approach is based on optimization...... modelling and assigns products and capacity expansions to production sites under the above constraints. It also considers the production complexity at the individual sites and the flexibility of the network. Our implementation results for a large manufacturing network reveal substantial possible cost...... reductions compared to the traditional manual planning results of our industrial partner....

  10. Air-sea interactions and exchanges

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.

    occurred in fairly high and rather uniform concentrations throughout the water column, and although its production through photo-oxidation in the surface layer probably represented an important sink of DMS, significant amounts of the latter should...

  11. Low income product innovation

    Directory of Open Access Journals (Sweden)

    Maria Cecília Sobral


    Full Text Available At affluent markets, the literature on product development management tells us to aggregate value and technology, to differentiate products and to launch fast. And at the low-income markets? This exploratory research defines a popular product, characterizes and measures their markets in Brazil, and identifies innovation strategies for them. The results suggest that the effective strategic orientation differs from affluent markets. It includes: to enhance the auto service component; to identify and service the key functionalities to the targeted public; to standardize products and increase the production scale; to extend the product life cycle; to use convenient distribution and marketing channels; to build product images that have appeal in the popular market; to offer longer financing horizons with befittingly lower installments. Data came from market researches and general demographic census. General media published stories were used to identify companies and their strategies. And a few case studies allowed the authors a deeper exploration of the relevant themes.

  12. Petroleum production systems

    Energy Technology Data Exchange (ETDEWEB)

    Economides, M.J.; Hill, A.D.; Ehlig-Economides, C.


    Petroleum production engineering attempts to maximize production in two connected systems, the reservoir and the artificial structures related to a well field. Determining whether it is economically feasible to drill a discovered source requires a familiarity with a variety of topics and theories. This book devotes the first six chapters to these concepts, including production from undersaturated oil reserves, production from two-phase reservoirs, production from natural gas reservoirs, skin effects, and gravel pack completions. The second part of the production engineer`s mission is maximization of output in the artificial structures, which include the well, bottomhole, and wellhead assemblies, and the surface gathering, separation, and storage facilities. This general system is discussed throughout the remainder of the book. Chapter topics include wellbore flow performance, forecast of well production, well test design and data acquisition, matrix acidizing, hydraulic fracturing for well simulation, gas lift, and systems analysis.

  13. Play as productionproduction as game?

    DEFF Research Database (Denmark)

    Eichberg, Henning


    “play” and “game” are, and of their social as well as political significance. At the municipal level, the city of Odense – “city of Hans Christian Andersen” – is branding itself as “city of play”. On the international level, Danish play-related products have expanded on the world market. In the field...... of sport, Danish sport is not just elite sport, but also organized in local associations. People meet in mass summer festivals of popular sport. Folk Academies develop sport as personal development, often in an experimental way. Street sports, parkour, play and games are promoted. Civil society is a basis....... This can be questioned in a world of expanding high tech games and robot toys, as well as a commercial sport and entertainment industry. At a closer examination, it is not only the essence of play that is open to debate, but also how production and productivity are to be understood....

  14. Specification of Products and Product Lines

    Directory of Open Access Journals (Sweden)

    Ariel Gonzalez


    Full Text Available The study of variability in software development has become increasingly important in recent years. A common mechanism to represent the variability in a product line is by means of feature models. However, the relationship between these models and UML design models is not straightforward. UML statecharts are extended introducing variability in their main components, so that the behavior of product lines can be specified. The contribution of this work is the proposal of a rule-based approach that defines a transformation strategy from extended statecharts to concrete UML statecharts. This is accomplished via the use of feature models, in order to describe the common and variant components, in such a way that, starting from different feature configurations and applying the rule-based method, concrete state machines corresponding to different products of a line can be obtained.

  15. Energy efficiency in products and production

    Energy Technology Data Exchange (ETDEWEB)

    Tugrul, Kodaz [Arcelik (Turkey)], email:


    Energy efficiency is not simply about making energy savings, it is also about maintaining the quality of living conditions, service quality and volumes of production in industrial plants. Using energy effectively wherever and whenever possible in our everyday lives will most likely make a great positive contribution to our household budget, to the national economy and to the protection of the environment. Fossil fuels, like petroleum and coal, the most important energy sources, are being depleted. What is worse, greenhouse gas emissions, which cause global warming and climate change, are rising. So there is an urgent need to raise energy efficiency and prevent energy wastage. Economic development will be based on sustainable usage of natural resources. Therefore, a combined commitment to protecting the environment and preserving and ecological balance at every stage of production activities is the central guarantee natural resource sustainability. This paper provides information on various studies of how to achieve high energy efficiency with respect both to products and their production.

  16. Coal Production 1992

    Energy Technology Data Exchange (ETDEWEB)


    Coal Production 1992 provides comprehensive information about US coal production, the number of mines, prices, productivity, employment, productive capacity, and recoverable reserves to a wide audience including Congress, Federal and State agencies, the coal industry, and the general public. In 1992, there were 3,439 active coal mining operations made up of all mines, preparation plants, and refuse operations. The data in Table 1 cover the 2,746 mines that produced coal, regardless of the amount of production, except for bituminous refuse mines. Tables 2 through 33 include data from the 2,852 mining operations that produced, processed, or prepared 10 thousand or more short tons of coal during the period, except for bituminous refuse, and includes preparation plants with 5 thousand or more employee hours. These mining operations accounted for over 99 percent of total US coal production and represented 83 percent of all US coal mining operations in 1992.

  17. Global product development

    DEFF Research Database (Denmark)

    Hansen, Zaza Nadja Lee; Ahmed-Kristensen, Saeema


    Globalisation has enabled companies to globalise their product development process. Today, everything from manufacturing to R&D can be globally distributed. This has led to a more complex and disintegrated product development process. This paper investigates the impacts companies have experienced...... as a result of this, and how they have been addressed. Data was collected through case studies of five Danish multinational corporations. The findings showed that the companies experienced several challenges when they globalised their product development process. They consequently implemented various...... operational solutions to counteract the negative impacts with varying degrees of success. This paper presents a unique look into global product development through an investigation of its impact on the organisation, the product development process, and the product. Furthermore, it shows the solutions...

  18. Smallholder Poultry Production

    DEFF Research Database (Denmark)

    Kryger, Karsten Nellemann; Thomsen, Karin; Whyte, Michael

    , poorly developed. Models for developing animal health services for smallholders are also well known, but the regulatory reforms needed are not implemented. The outbreaks of highly pathogenic avian influxenza (HPAI) resulted in policies and regulations that have significant impact on the future structure...... poultry keeping to the income and internal household position of women. Institutional structures are not favourable to smallholder poultry production. The interventions that could enhance productivity are well recognized, but the animal health services needed to promote these interventions are, in general...... of poultry production and trade. Although it is too early to assess the long-term effects of HPAI on the poultry industry, there are emerging signs of restructuring – with a shift away from small-scale commercial production towards larger-scale production. Village production is, however, likely to persist....

  19. Product Platform Modeling

    DEFF Research Database (Denmark)

    Pedersen, Rasmus

    as important assets in a product platform, yet activities, working patterns, processes and knowledge can also be reused in a platform approach. Encapsulation is seen as a process in which the different elements of a platform are grouped into well defined and self-contained units which are decoupled from each......This PhD thesis has the title Product Platform Modelling. The thesis is about product platforms and visual product platform modelling. Product platforms have gained an increasing attention in industry and academia in the past decade. The reasons are many, yet the increasing globalisation...... and the change in the global economy seem to be major factors. Manufacturing companies have experienced an intensifying competition and many companies face increasing demands for reductions in costs and lead times in development and production. At the same time many customers have raised their demands...

  20. An infinite natural product


    Lipparini, Paolo


    We study an infinite countable iteration of the natural product between ordinals. We present an "effective" way to compute this countable natural product, in the non trivial cases the result depends only on the natural sum of the degrees of the factors, where the degree of a nonzero ordinal is the largest exponent in its Cantor normal form representation. Thus we are able to lift former results about infinitary sums to infinitary products. Finally, we provide an order-theoretical characteriza...



    Catalin Mihail BARBU


    In this paper I discussed the factors that influence the cultural adaptation of products. Globalization determines the companies to operate abroad; therefore the firms sell their products to markets where the consumer patterns might differ from their national market. It is of high importance to be able to understand and to adapt to local consumer habits. The culture has a strong influence on products adaptation in particular, and on international marketing in general. Companies must be able t...

  2. Production Subcontracting and Location


    Holl, Adelheid


    Using data from a panel of Spanish manufacturing firms, I examine factors that explain firms’ production subcontracting decisions and test whether there is any evidence that production subcontracting is facilitated in areas typically associated with higher agglomeration economies. The results show that location matters. Firms in industry agglomerations are more likely to subcontract production activities. While in general, larger and older firms as well as high wage firms show a greater proba...

  3. Product placement in movie


    Savchenko, I. I.; САВЧЕНКО И.И.


    The concept of product placement itself is nothing new. The area is; however, experiencing a significant growth due to the difficulties of reaching the consumers with traditional advertising. The ongoing debate an a discussion on concerning product placement provides the foundation of the article. Based on this, the aim of this article is to gain a deeper understanding of this area. Also, the aim is to gain a deeper understanding specifically about the process of product placement and the cri...

  4. DRP Product Inventory (United States)


    a. Product Name: Real-Time Tide Reporting System b. Product Key Word: Measure e..- System c. Technical Key Word: Hydrosurvey & Dredging Operations d...Description: Accurate local real-time tide data permit more accurate hydrosurvey operations, and can minimize the over-depth dredging necessary to...Universal Heave Compensation System b. Product Key Word: Plans and Specifications c. Technical Key Word: Hydrosurvey d. Description: A common problem when

  5. Counterfeit-Product Trade.


    Grossman, Gene M; Shapiro, Carl


    We analyze a two-country model of trade in both legitimate and counterfeit products. Domestic firms own trademarks and establish reputations for delivering high-quality products in a steady-state equilibrium. Foreign suppliers export legitimate low-quality merchandise and counterfeits of domestic brand-name goods. Heterogeneous home consumers either purchase low-quality imports or buy brand-name products, rationally expecting some degree of counterfeiting of the latter. We characterize a coun...

  6. Counterfeit Product Trade


    Grossman, Gene


    We analyze a two-country model of trade in both legitimate and counterfeit products. Domestic firms own trademarks and establish reputations for delivering high-quality products in a steady-state equilibrium. Foreign suppliers export legitimate low-quality merchandise and counterfeits of domestic brand-name goods. Heterogeneous home consumers either purchase low-quality imports or buy brand-name products, rationally expecting some degree of counterfeiting of the latter. We characterize a coun...

  7. Productivity in Public Services


    Helen Simpson


    This paper discusses issues arising in the measurement of productivity in public services. Compared to measuring productivity in the private sector difficulties arise because the output of public services is often un-priced and because some public services are consumed collectively. A key problem is measuring the full range of outputs and quality improvements delivered by public sector organisations that are valued by society. Without comprehensive measures of output productivity statistics m...

  8. Southern pulpwood production, 2008 (United States)

    Tony G. Johnson; Carolyn D. Steppleton; James W. Bentley


    The South’s production of pulpwood increased from 65.7 million cords in 2007 to 67.0 million cords in 2008. Roundwood production increased by 1.2 million cords to 48.8 million cords and accounted for 73 percent of the South’s total pulpwood production. The use of wood residue remained stable at 18.2 million cords. Georgia led the South...

  9. Emulsified Water Products


    Elif Tuğçe AKSUN


    Seafood is very important depending on having high protein rate and easily digestibility by human, for supply to an important part of animal protein needed. Determining the quality of emulsion-type products, emulsion stability, viscosity and gel strength properties are very important. In the production of products specified in this property emulsion; the main protein ratio and properties of raw material used while you; emulsion pH, temperature, ionic violence, mixing speed, type of fat and...

  10. Product Pre-Measure

    Directory of Open Access Journals (Sweden)

    Endou Noboru


    Full Text Available In this article we formalize in Mizar [5] product pre-measure on product sets of measurable sets. Although there are some approaches to construct product measure [22], [6], [9], [21], [25], we start it from σ-measure because existence of σ-measure on any semialgebras has been proved in [15]. In this approach, we use some theorems for integrals.



    Ľubomíra Juhaniaková; Miroslava Kačániová


    The aim of this work was to determine microbiological quality of confectionery products. In confectionery products microbiological parameters: coliforms bacteria, microscopic filamentous fungi and yeasts, Salmonella sp. and staphylococci were observed. The confectionery products were evaluated: Kremes - honey cube, roll Arabica, roll Rona, roll stuffed with apricot cream, honey cube, pinwheel caramel, Sachovnica cut, Zora cut and curd cake. For microbiological tests 18 samples of confectioner...

  12. Sicilian potential biogas production


    Antonio Comparetti; Pierluigi Febo; Carlo Greco; Santo Orlando; Kestutis Navickas; Kestutis Venslauskas


    This study is aimed at predicting the Sicilian potential biogas production, using the Organic Fraction of Municipal Solid Waste (OFMSW), animal manure and food industry by-products, in a region where only one biogas plant using MSW and one co-digestion plant are nowadays available. The statistical data about OFMSW, the number of animals bred in medium and large farms and the amounts of by-products of food processing industries were evaluated, in order to compute the Sicilian potential biogas ...


    Directory of Open Access Journals (Sweden)

    V.M. Sineglazov


    Full Text Available  Research results of representation of product structure made by means of CADDS5 computer-aided design (CAD system, Product Data Management Optegra (PDM system and Product Life Cycle Management Wind-chill system (PLM, are examined in this work. Analysis of structure component development and its storage in various systems is carried out. Algorithms of structure transformation required for correct representation of the structure are considered. Management analysis of electronic mockup presentation of the product structure is carried out for Windchill system.

  14. Improving pension product design

    DEFF Research Database (Denmark)

    Konicz, Agnieszka Karolina; Mulvey, John M.

    The paper develops a pension product that can be oered in a dened contribution pension scheme as a deferred or immediate life annuity. The product is characterized by linking an individual's savings directly to market returns and differs from the products available in the market by being adjusted......, expected lifetime salary progression, mandatory and voluntary pension contributions, expected state retirement pension, choice of assets, subjective lifetime expectancy and bequest motive. Specically, the asset allocation strategy, the payout prole and the level of insured sum dening the new product...

  15. Software product lines


    Cortés Verdín, María Karen


    A Software Product Line is a “set of software-intensive systems sharing a common, managed set of features that satisfy the specific needs of a particular market segment or mission and that are developed from a common set of core assets in a prescribed way”1. A software product line (or software product family) approach promotes planned and proactive reuse of core assets and architecture-centric development, achieving a substantial increment in product quality and a reduced time to market. Bec...


    Directory of Open Access Journals (Sweden)

    Edu Grieco Mazzini Junior


    Full Text Available Design or product development? The questioning in relation to the employment of such terminology dates back to possible misconceptions regarding interpretation and approach them. Therefore, it can be stated that there are differences between these two terms? In this context, we highlight two views concerning the origin of the design. The first character creative and based on pre-industrial revolution, based on projective and methodologies directed towards the practice of designing products. And second, where design is understood as an industrial process: the development of new products includes, besides a creative procedure are developed, and symbolic formal solutions for products, but also a technical procedure based on the definition of the requirements concerning the product engineering. Is this the most widely accepted interpretation? theoretical studies were conducted from interpretations of the concept of the design proposed by the International Council of Societies of Industrial Design – ICSDI (2012, and for the characterization of the process of product development, we sought to develop an analogy between these two terminologies and can be proved that the use of one of terminology will not cause deviations of interpretation, since both deal with the life cycle of the product. The main results obtained until now the definition of design proposed by the ICSID where it is characterized as a creative activity focused on the complete life cycle of products is the more approaches of the concept of product development.

  17. Cleaning Products Pilot Project (United States)

    This 1997 case study documents a three-year effort to identify and compare environmentally preferable commercial cleaning products and to implement the Environmentally Preferable Purchasing Program (EPP).


    DEFF Research Database (Denmark)

    Cheng, Yang; Madsen, Erik Skov

    This paper mainly aims to explore how SMEs internationalise their production. Directed by this objective, a new practice adopted by five Danish SMEs to internationalise their production to China is identified, which to our knowledge has never been reported by any of the existing literature. The new...... practice is further analysed in terms of (1) general information of each case company; (2) motivation of production internationalisation of each case company; (3) limitations as SMEs to internationalise production; (4) operational activities during the internationalization; (5) benefits of joint effort...

  19. Optimizing production under uncertainty

    DEFF Research Database (Denmark)

    Rasmussen, Svend

    This Working Paper derives criteria for optimal production under uncertainty based on the state-contingent approach (Chambers and Quiggin, 2000), and discusses po-tential problems involved in applying the state-contingent approach in a normative context. The analytical approach uses the concept...... of state-contingent production functions and a definition of inputs including both sort of input, activity and alloca-tion technology. It also analyses production decisions where production is combined with trading in state-contingent claims such as insurance contracts. The final part discusses...

  20. The Internationalisation of Production

    DEFF Research Database (Denmark)

    Yang, Cheng; Madsen, Erik Skov


    This paper mainly aims to explore how SMEs internationalise their production. Directed by this objective, a new practice adopted by five Danish SMEs to internationalise their production to China is identified, which to our knowledge has never been reported by any of the existing literature. The new...... practice is further analysed in terms of (1) general information of each case company; (2) motivation of production internationalisation of each case company; (3) limitations as SMEs to internationalise production; (4) operational activities during the internationalization; (5) benefits of joint effort...

  1. Accounting for productivity

    DEFF Research Database (Denmark)

    Aiyar, Shekhar; Dalgaard, Carl-Johan Lars


    The development accounting literature almost always assumes a Cobb-Douglas (CD) production function. However, if in reality the elasticity of substitution between capital and labor deviates substantially from 1, the assumption is invalid, potentially casting doubt on the commonly held view...... that factors of production are relatively unimportant in accounting for differences in labor productivity. We use international data on relative factor shares and capital-output ratios to formulate a number of tests for the validity of the CD assumption. We find that the CD specification performs reasonably...... well for the purposes of cross-country productivity accounting....

  2. Lipid Production from Nannochloropsis. (United States)

    Ma, Xiao-Nian; Chen, Tian-Peng; Yang, Bo; Liu, Jin; Chen, Feng


    Microalgae are sunlight-driven green cell factories for the production of potential bioactive products and biofuels. Nannochloropsis represents a genus of marine microalgae with high photosynthetic efficiency and can convert carbon dioxide to storage lipids mainly in the form of triacylglycerols and to the ω-3 long-chain polyunsaturated fatty acid eicosapentaenoic acid (EPA). Recently, Nannochloropsis has received ever-increasing interests of both research and public communities. This review aims to provide an overview of biology and biotechnological potential of Nannochloropsis, with the emphasis on lipid production. The path forward for the further exploration of Nannochloropsis for lipid production with respect to both challenges and opportunities is also discussed.


    National Research Council Canada - National Science Library

    Randall G Holcombe


      In neoclassical theory, product differentiation provides consumers with a variety of different products within a particular industry, rather than a homogeneous product that characterizes purely competitive markets...

  4. Production control system specified quality sausage products

    Directory of Open Access Journals (Sweden)

    A. V. Tokarev


    Full Text Available The problem of management of production target in technological system of production of sausages of the set quality is considered in article. Decomposition of technological system is considered. Functions of management are allocated: formation of an optimum compounding of forcemeat, expert analysis of a compounding, laboratory analysis of a compounding and its statement. Information technology of interaction of these functions is offered. The mathematical problem definition of finding of an optimum compounding meat product with use of possible substitutes of ingredients is presented. This mathematical problem is a classical linear programming problem whose solution has the standard program. Since the manufacture of the finished product are various nonlinear effects are taken into account at the present time it is practically impossible, the methodology provided in this operation "Expert analysis of the formulation" and "Laboratory analysis of the finished product." An example of calculating the optimum alternative base recipe "Sausages “Viennese with cheese”" TS 9213-010-40155161-2002. For an alternative formulation demands were made at a cost of meat, the ingredient composition, as well as the final product organoleptic and physic-chemical indicators should comply with regulatory requirements "Sausages “Viennese with cheese”" TS 9213-010-40155161-2002. Indicator acid activity (pH calculated stuffing formulation should be in the range 6.0-6.3. As a partial replacement for the main raw material have been proposed acceptable substitutes. It was necessary to calculate on the basis of the formulation "Sausages “Viennese with cheese”" TS 9213-010-40155161-2002 optimal price and quality alternative formulation. As a result of depreciation of the value of alternative stuffing recipe was 14,5 % when all of the restrictions on the consumer properties. The proposed information technology implemented in the software package "Multi

  5. Volatile products controlling Titan's tholins production

    KAUST Repository

    Carrasco, Nathalie


    A quantitative agreement between nitrile relative abundances and Titan\\'s atmospheric composition was recently shown with a reactor simulating the global chemistry occurring in Titan\\'s atmosphere (Gautier et al. [2011]. Icarus, 213, 625-635). Here we present a complementary study on the same reactor using an in situ diagnostic of the gas phase composition. Various initial N 2/CH 4 gas mixtures (methane varying from 1% to 10%) are studied, with a monitoring of the methane consumption and of the stable gas neutrals by in situ mass spectrometry. Atomic hydrogen is also measured by optical emission spectroscopy. A positive correlation is found between atomic hydrogen abundance and the inhibition function for aerosol production. This confirms the suspected role of hydrogen as an inhibitor of heterogeneous organic growth processes, as found in Sciamma-O\\'Brien et al. (Sciamma-O\\'Brien et al. [2010]. Icarus, 209, 704-714). The study of the gas phase organic products is focussed on its evolution with the initial methane amount [CH 4] 0 and its comparison with the aerosol production efficiency. We identify a change in the stationary gas phase composition for intermediate methane amounts: below [CH 4] 0=5%, the gas phase composition is mainly dominated by nitrogen-containing species, whereas hydrocarbons are massively produced for [CH 4] 0>5%. This predominance of N-containing species at lower initial methane amount, compared with the maximum gas-to solid conversion observed in Sciamma-O\\'Brien et al. (2010) for identical methane amounts confirms the central role played by N-containing gas-phase compounds to produce tholins. Moreover, two protonated imines (methanimine CH 2NH and ethanamine CH 3CHNH) are detected in the ion composition in agreement with Titan\\'s INMS measurements, and reinforcing the suspected role of these chemical species on aerosol production. © 2012 Elsevier Inc.

  6. Production monitoring system for understanding product robustness

    DEFF Research Database (Denmark)

    Boorla, Srinivasa Murthy; Howard, Thomas J.


    study is used to demonstrate how the monitoring system can be used to efficiently guide corrective action to improve product performance. It is claimed that the monitoring system can be used to dramatically cut the time taken to identify, planand execute corrective action related to typical quality...... to be seven days. Using the monitoring system for the PRECI‐IN case, similar corrective action would have been achieved almost immediately....

  7. Training for Productivity. (United States)

    Maglen, Leo; Hopkins, Sonnie; Burke, Gerald

    An exploratory study was conducted to evaluate the utility of a method to demonstrate that Australian enterprises that invest in the training of their employees gain a return from that investment through an increase in employee productivity. The method, which compares enterprise expenditure on training of personnel with labor productivity across a…

  8. Production (information sheets)

    NARCIS (Netherlands)


    Documentation sheets: Geo energy 2 Integrated System Approach Petroleum Production (ISAPP) The value of smartness 4 Reservoir permeability estimation from production data 6 Coupled modeling for reservoir application 8 Toward an integrated near-wellbore model 10 TNO conceptual framework for "E&P

  9. The Productive Programmer

    CERN Document Server

    Ford, Neal


    Anyone who develops software for a living needs a proven way to produce it better, faster, and cheaper. The Productive Programmer offers critical timesaving and productivity tools that you can adopt right away, no matter what platform you use. Master developer Neal Ford details ten valuable practices that will help you elude common traps, improve your code, and become more valuable to your team.

  10. Productivity of Stream Definitions

    NARCIS (Netherlands)

    Endrullis, J.; Grabmayer, C.A.; Hendriks, R.D.A.; Ishihara, A.; Klop, J.W.


    We give an algorithm for deciding productivity of a large and natural class of recursive stream definitions. A stream definition is called 'productive' if it can be evaluated continually in such a way that a uniquely determined stream in constructor normal form is obtained as the limit. Whereas

  11. Productivity of Stream Definitions

    NARCIS (Netherlands)

    Endrullis, Jörg; Grabmayer, Clemens; Hendriks, Dimitri; Isihara, Ariya; Klop, Jan


    We give an algorithm for deciding productivity of a large and natural class of recursive stream definitions. A stream definition is called ‘productive’ if it can be evaluated continuously in such a way that a uniquely determined stream is obtained as the limit. Whereas productivity is undecidable


    Directory of Open Access Journals (Sweden)

    Svetlana Trajković


    Full Text Available The modern age in which we live today, modern and highly advanced technology that follows us all, gives great importance in the management of production within the computer support of management. Computer applications in production, the organization of production systems, in the organization of management and business, is gaining in importance. We live in a time when more and more uses computer technology and thus gives the opportunity for a broad and important area of application of computer systems in production, as well as some methods that enable us to successful implementation of a computer, such as in the management of production. Computer technology speeds up the processing and transfer of Information By needed in decision-making at various levels of management. Computer applications in production management and organizational management business production system gets more and more. New generation of computers caused the first technological revolution in industry. On these solutions the industry has been able to use all the modern technology of computers in manufacturing, automation and production management .

  13. Contracting Productivity Growth

    NARCIS (Netherlands)

    Francois, P.; Roberts, J.


    In this paper, we analyze the interactions between growth and the contracting environment in the production sector.Allowing incompleteness in contracting implies that viable production relationships for firms and workers, and therefore the profitability of industries, depend on the rates of

  14. Green product innovation strategy

    NARCIS (Netherlands)

    Driessen, P.H.


    Over the last decades, companies have started to incorporate green issues in product innovation strategies. This dissertation studies green product innovation strategy, its antecedents and its outcomes. A three-stage approach is followed. In the first stage, the topic is explored and a preliminary

  15. Improved wound care product

    DEFF Research Database (Denmark)


    The present invention pertains to use of sodium diacetate (NaHAc 2) as an antimicrobial agent against bacteria growing in biofilms. The aspects of the invention include a wound care product comprising sodium diacetate, a kit comprising a wound care product,and a methodof treating an infected wound....

  16. Marketing Novel Fruit Products

    NARCIS (Netherlands)

    ’T Riet, Van Jonathan; Onwezen, M.C.; Bartels, Jos; Lans, Van Der I.A.; Kraszewska, Magdalena


    The purpose of this study was to compare the influence of four different marketing claims and price information on consumers’ product choices for novel fruits and novel fruit products, using a choice experiment. In total, 1,652 people in Greece (n = 400), the Netherlands (n = 419), Poland (n =

  17. Product Placement in Cartoons

    Directory of Open Access Journals (Sweden)

    Irena Oroz Štancl


    Full Text Available Product placement is a marketing approach for integrating products or services into selected media content. Studies have shown that the impact of advertising on children and youth are large, and that it can affect their preferences and attitudes. The aim of this article is to determine the existing level of product placement in cartoons that are broadcast on Croatian television stations. Content analysis of cartoons in a period of one month gave the following results: in 30% of cartoons product placement was found; most product placement were visual ads, in 89%, however, auditory product placement and plot connection was also found. Most ads were related to toys and it is significant that even 65% of cartoons are accompanied by a large amount of products available on the Croatian market. This is the result of two sales strategies: brand licensing (selling popular cartoon characters to toys, food or clothing companies and cartoon production based on existing line of toys with the sole aim of making their sales more effective.

  18. Interleaved Product LDPC Codes


    Baldi, Marco; Cancellieri, Giovanni; Chiaraluce, Franco


    Product LDPC codes take advantage of LDPC decoding algorithms and the high minimum distance of product codes. We propose to add suitable interleavers to improve the waterfall performance of LDPC decoding. Interleaving also reduces the number of low weight codewords, that gives a further advantage in the error floor region.

  19. Diffractive production of mesons

    Directory of Open Access Journals (Sweden)

    Schicker Rainer


    Full Text Available The interest in the study of diffractive meson production is discussed. The description of diffraction within Regge phenomenology is presented, and the QCD-based understanding of diffractive processes is given. Central production is reviewed, and the corresponding main results from the COMPASS experiment and from the experiments at the ISR, RHIC, TEVATRON and LHC collider are summarised.

  20. Product Architecture Compressor Starter.


    Brudevoll, Kai


    Developing and designing new product architecture for electrical starters. Questing what system can handle high variety both today and tomorrow's variety. Methods found in literature are applied. In this thesis technology platform is chosen and developed to prototype stage. Software for handling product structure and documentation developed. Solutions to handle generational variations are suggested.

  1. Risks of Leveraged Products

    NARCIS (Netherlands)

    A. Di Cesare (Antonio)


    textabstractLeveraged investments have become a fundamental feature of modern economies. The new financial products allow people to take greater-than-usual exposures to risk factors. This thesis analyzes several different aspects of the risks involved by some frequently used leveraged products:

  2. J/ψ production

    Indian Academy of Sciences (India)

    Abstract. For more than 25 years J Ψ production has helped to sharpen our understanding of. QCD. In proton induced reaction some observations are rather well understood while others are still unclear. The current status of the theory of J Ψ production will be sketched, paying special attention to the issues of formation time ...

  3. Conditions for industrial production

    DEFF Research Database (Denmark)

    Jensen, Karsten Ingerslev; Schultz, Jørgen Munthe; Brauer, H.


    The possibilities of making xerogel glazings in an industrial way is discussed and a schematic outline of a production line is presented.......The possibilities of making xerogel glazings in an industrial way is discussed and a schematic outline of a production line is presented....

  4. economics of rice production

    African Journals Online (AJOL)

    ABSTRACT. Local rice production is being promoted in Ghana to reduce the' dependence on im- ports, ensure stable low-prices food for the population and also create employment. This paper examines three rice production systems; Upland, Valley Bottom and Irri- gated, in the Upper East Region of Ghana with a view to ...

  5. Global product development

    DEFF Research Database (Denmark)

    Taylor, Thomas Paul; Ahmed-Kristensen, Saeema


    Selecting key performance indicators in conventional product development is a challenging task for project management and is compound by global product development. Informed from the findings of two in depth case studies conducted with large Danish manufacturing companies, in this paper we develo...

  6. Questionnaire typography and production. (United States)

    Gray, M


    This article describes the typographic principles and practice which provide the basis of good design and print, the relevant printing processes which can be used, and the graphic designer's function in questionnaire production. As they impose constraints on design decisions to be discussed later in the text, the various methods of printing and production are discussed first.

  7. Dictionaries for text production

    DEFF Research Database (Denmark)

    Fuertes-Olivera, Pedro; Bergenholtz, Henning


    and free online dictionaries. The Diccionario español para la producción de textos is an example of a general text production dictionary that makes use of internet technologies, is based on a lexicographic theory, contains all the lexicographic data that users need in a production situation, and aims...


    Directory of Open Access Journals (Sweden)

    Ștefan GHIMIȘI,


    Full Text Available Paper aims to present both the methodology for the design of a product and product design methods. It presents the theory of inventive problem solving (TRIZ, witch with its search concepts becomes an application of rules and laws from "experimental" concrete data abstraction . TRIZ role is to generate ideas carrier solution.

  9. (Hqcf) for Bread Production

    African Journals Online (AJOL)


    namely Food Concepts Butterfield, and. Leventis-Value bread, had begun inclusion of. HQCF in bread production. There is however the need for the small scale bread bakers to equally embrace HQCF inclusion in bread production in the country. In order for this aim to be achieved, concerted efforts had been made by the ...

  10. Process, Product, and Playmaking (United States)

    Fisher, Maisha T.; Purcell, Susie Spear; May, Rachel


    This article examines relationships among process, product, and playmaking in a southeastern playwriting and performance program for teen girls, Playmaking for Girls (PFG). The authors have chosen to focus on tensions between process and product. Such tensions are present in the challenges teachers experience when privileging student-centered…

  11. Marketing technologically advanced products

    NARCIS (Netherlands)

    Bender, Horst


    This paper calls for a merger of technology and marketing under a customer value perspective; for an enhancement of the traditional technological innovation orientation of the technology-based firm with a market thrust. It establishes technology-based products as product-service offerings that are


    Directory of Open Access Journals (Sweden)

    Adrian MICU


    Full Text Available Cost advantages may be either internal or external. Internal economics of scope, scale, or experience, and external economies of focus or logistical integration, enable a company to produce some products at a lower cost than the competition. The coordination of pricing with suppliers, although not actually economizing resources, can improve the efficiency of pricing by avoiding the incrementalization of a supplier's nonincremental fixed costs and profit. Any of these strategies can generate cost advantages that are, at least in the short run, sustainable. Even cost advantages that are not sustainable, however, can generate temporary savings that are often the key to building more sustainable cost or product advantages later.. Even when a product's physical attributes are not readily differentiable, opportunities to develop product advantages remain. The augmented product that customers buy is more than the particular product or service exchanged. It includes all sorts of ancillary services and intangible relationships that make buying thesame product from one company less difficult, less risky, or more pleasant than buying from a competitor. Superior augmentation of the same basic product can add substantial value in the eyes of consumers, leading them to pay willingly what are often considerable price premiums.


    National Research Council Canada - National Science Library

    Sahid Susilo Nugroho; Rokhima Rostiani; Indriyo Gitosudarmo


    ...). The objective of this study is to investigate the impacts of COO on product evaluation in the Indonesian market by considering consumers' product familiarity and consumers' product involvement...

  14. Defining product service systems

    DEFF Research Database (Denmark)

    McAloone, Timothy Charles; Andreasen, Mogens Myrup


    , for example, a factor 20 improvement in our environmental performance. One attempt, however, has recently emerged, which combines the product as an artefact with the service that the product provides to the user. Through the combination of these two facets, the company retains ownership of the physical...... artefact and instead provides what the customer really wants the actual functionality from the product. This enables a series of potential improvements to the product´s performance throughout its lifecycle. The ideal of product service system (PSS) development is that all three stakeholder groups customer......, company and society benefit from the service systems related to each one of these dimensions, rather than simply one of the above. There are existing examples of the enhancement of business and market share by focusing on PSS, but this is often not a result of upfront strategy and ambitious goals. We...

  15. SONAbeam optical wireless products (United States)

    Carbonneau, Theresa H.; Mecherle, G. Stephen


    fSONA has developed an optical wireless line of products that will enable high bandwidth wireless connectivity, much like fiber optic technology has done for wired connectivity. All of the fSONA products use wavelengths around 1.5 micrometers both for eye safety and for maximum commonality with fiber optic technology. Initial products provide either OC-3 (155 Mbps) or Fast Ethernet (125 Mbps). The 2 km unit is fixed mounted and provides a relatively large beamwidth to compensate for building motion. The 4 km unit utilizes a narrow transmit beamwidth with active pointing for motion compensation. Trials of the units with key customers begin in second quarter 2000, with volume production of the 2 km- unit beginning in third quarter and the 4 km unit in the fourth quarter. Product designs for 622 Mbps and 1.25 Gbps should be completed prior to the end of the 2000.

  16. Product Architecture Modularity Strategies

    DEFF Research Database (Denmark)

    Mikkola, Juliana Hsuan


    The focus of this paper is to integrate various perspectives on product architecture modularity into a general framework, and also to propose a way to measure the degree of modularization embedded in product architectures. Various trade-offs between modular and integral product architectures...... and how components and interfaces influence the degree of modularization are considered. In order to gain a better understanding of product architecture modularity as a strategy, a theoretical framework and propositions are drawn from various academic literature sources. Based on the literature review......, the following key elements of product architecture are identified: components (standard and new-to-the-firm), interfaces (standardization and specification), degree of coupling, and substitutability. A mathematical function, termed modularization function, is introduced to measure the degree of modularization...

  17. Syntax production in bilinguals. (United States)

    Golestani, Narly; Alario, F-Xavier; Meriaux, Sébastien; Le Bihan, Denis; Dehaene, Stanislas; Pallier, Christophe


    We used fMRI to examine the functional correlates of syntactical processing in the first (L1) and second (L2) languages of non-proficient, late bilinguals. Subjects either covertly read words or produced sentences from them. Syntactical production during sentence production activated regions including left inferior frontal (LIFG) gyrus and the supplementary motor area in both languages. Analyses performed on the LIFG activation identified on a subject-by-subject basis revealed greater activation in L2 compared to L1 during sentence production and during word reading, consistent with previous work suggesting that greater cognitive effort may be subserved by less well-tuned neural representations that require greater neuronal activity. Remarkably, there was a greater separation in the LIFG activations in L1 versus L2 in less compared to more proficient bilinguals during syntax production, suggesting a functional reorganisation of regions involved in syntactical production as a function of syntactical proficiency.

  18. Thermophilic Biohydrogen Production

    DEFF Research Database (Denmark)

    Karakashev, Dimitar Borisov; Angelidaki, Irini


    Dark fermentative hydrogen production at thermophilic conditions is attractive process for biofuel production. From thermodynamic point of view, higher temperatures favor biohydrogen production. Highest hydrogen yields are always associated with acetate, or with mixed acetate- butyrate type...... fermentation. On the contrary the hydrogen yield decreases, with increasing concentrations of lactate, ethanol or propionate. Major factors affecting dark fermentative biohydrogen production are organic loading rate (OLR), pH, hydraulic retention time (HRT), dissolved hydrogen and dissolved carbon dioxide...... concentrations, and soluble metabolic profile (SMP). A number of thermophilic and extreme thermophilic cultures (pure and mixed) have been studied for biohydrogen production from different feedstocks - pure substrates and waste/wastewaters. Variety of process technologies (operational conditions...

  19. Sustainable Biocatalytic Biodiesel Production

    DEFF Research Database (Denmark)

    Güzel, Günduz

    and chemical equilibria as part of his main sustainable biodiesel project. The transesterification reaction of vegetable oils or fats with an aliphatic alcohol – in most cases methanol or ethanol – yields biodiesel (long-chain fatty acid alkyl esters – FAAE) as the main product in the presence of alkaline....../acid catalysts or biocatalysts (free or immobilised lipase enzymes). The reaction by-product glycerol is immiscible with the ester products (FAAE and oils/fats) in addition to the partial miscibility problem of methanol or ethanol with oils/fats. The insoluble parts of alcohol feeds or by-products form emulsion......As part of his PhD studies, Gündüz Güzel examined the thermodynamics of reactions involved in biocatalytic biodiesel production processes, with a specific focus on phase equilibria of reactive systems. He carried out the thermodynamic analyses of biocatalytic processes in terms of phase...

  20. Production measurements at LHCb

    CERN Document Server



    The $\\text{LHC}b$ detector, with its excellent momentum resolution and flexible trigger strategy, is ideally suited for measuring heavy quark and quarkonia production properties. In addition, the new system of forward shower counters installed upstream and downstream has begun to be used, therefore the experiment is being suited to measure central exclusive production. The $\\text{LHC}b$ measurements of inclusive and differential cross-sections of the production of $J/\\psi$ resonance and $J/\\psi$ pairs, as well bottom quarks and $Z^0$ boson, based on Run 2 datasets are summarized. Finally, results on the prompt production of open charm hadrons and the exclusive production of charmonium are discussed.

  1. Chemical Product Design

    DEFF Research Database (Denmark)

    Gani, Rafiqul


    This paper highlights for a class of chemical products, the design process, their design with respect to the important issues, the need for appropriate tools and finally, lists some of the challenges and opportunities for the process systems engineering (PSE)/computer-aided process engineering...... (CAPE) community. The chemical products considered belong to the following types: chemical/biochemical/agrochemical products, coatings and solvents, food (nutraceuticals), HIM (household, industrial and institutional), personal care, pharmaceuticals and drugs. The challenges and opportunities...... are highlighted in terms of the needs for multi-level modeling with emphasis on property models that are suitable for computer-aided applications, flexible solution strategies that are able to solve a large range of chemical product design problems and finally, a systems chemical product design framework...

  2. Hydrogen production by Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Chaudhuri Surabhi


    Full Text Available Abstract The limited fossil fuel prompts the prospecting of various unconventional energy sources to take over the traditional fossil fuel energy source. In this respect the use of hydrogen gas is an attractive alternate source. Attributed by its numerous advantages including those of environmentally clean, efficiency and renew ability, hydrogen gas is considered to be one of the most desired alternate. Cyanobacteria are highly promising microorganism for hydrogen production. In comparison to the traditional ways of hydrogen production (chemical, photoelectrical, Cyanobacterial hydrogen production is commercially viable. This review highlights the basic biology of cynobacterial hydrogen production, strains involved, large-scale hydrogen production and its future prospects. While integrating the existing knowledge and technology, much future improvement and progress is to be done before hydrogen is accepted as a commercial primary energy source.

  3. Product identification file

    Energy Technology Data Exchange (ETDEWEB)

    Gray, C.E. (ed.)


    This product identification file was compiled as an aid to the industrial hygienist who may encounter the products listed in surveys for and studies of occupational health hazards. It is pointed out that the chemical composition of a product may vary from year to year and some components may be added or deleted without an indication on the label. Some of the data in this file may not be complete depending on the analysis requested. For example, a solvent may be the only component for which the product was analyzed. The file is arranged by listing the chemical manufacturer, followed by the trade name. In cases where no manufacturer is known, the trade name appears in alphabetical order. The log number and the chemist who analyzed the product are listed for reference.

  4. Greenhouse production systems for people

    NARCIS (Netherlands)

    Giacomelli, G.A.; Sase, S.; Cramer, R.; Hoogeboom, J.; McKenzie, A.; Parbst, K.; Sacrascia-Mugnozza, G.; Selina, P.; Sharp, D.A.; Voogt, J.O.; Weel, van P.A.; Mears, D.


    Environmentally sound greenhouse production requires that: demand for market products is understood; greenhouse design addresses the climate circum-stances; input resources are available and consumed efficiently, and; there must be a reasonable balance of production products to the environmental

  5. Product sounds : Fundamentals and application

    NARCIS (Netherlands)

    Ozcan-Vieira, E.


    Products are ubiquitous, so are the sounds emitted by products. Product sounds influence our reasoning, emotional state, purchase decisions, preference, and expectations regarding the product and the product's performance. Thus, auditory experience elicited by product sounds may not be just about

  6. Understanding in-situ ozone production in the summertime through radical observations and modelling studies during the Clean air for London project (United States)

    Whalley, Lisa; Stone, Daniel; Sharp, Thomas; Garraway, Shani; Bannan, Thomas; Percival, Carl; Hopkins, James; Holmes, Rachel; Hamilton, Jacqui; Lee, James; Laufs, Sebastian; Kleffmann, Jörg; Heard, Dwayne


    With greater than 50 % of the global population residing in urban conurbations, poor urban air quality has a demonstrable effect on human health. OH and HO2 radicals, (collectively termed HOx) together with RO2 radicals, mediate virtually all of the oxidative chemistry in the atmosphere, being responsible for the transformation of primary emissions into secondary pollutants such as NO2, O3 and particulates. Here we present measurements of OH, HO2, partially speciated RO2 (distinguishing smaller alkane related RO2 from larger alkane/alkene/aromatic related RO2), ClNO2 and OH reactivity measurements taken during the ClearfLo campaign in central London in the summer of 2012. Comparison with calculations from a detailed box model utilising the Master Chemical Mechanism v3.2 tested our ability to reproduce radical levels, and enabled detailed radical budgets to be determined, highlighting for example the important role of the photolysis of nitrous acid (HONO) and carbonyl species as radical sources. Speciation of RO2 enabled the break-down of ozone production from different classes of VOCs to be calculated directly and compared with model calculations. Summertime observations of radicals have helped to identify that increases in photolytic sources of radicals on warm, sunny days can significantly increase local ozone concentrations leading to exceedances of EU air quality recommendations of 60 ppbV. The photolytic breakdown of ClNO2 to Cl atoms can more than double radical concentrations in the early morning; although the integrated increase in radical concentrations over a 24 hr period in model runs when ClNO2 photolysis is included is more modest. On average we calculate just under a 1 ppb increase in ozone due to the presence of ClNO2 in London air. OH reactivity was found to be greatest during morning and evening rush hours. Good agreement between the modelled OH reactivity and observations could be achieved when reactivity associated with model generated photo-oxidation


    Directory of Open Access Journals (Sweden)

    Georgiana Melania COSTAICHE


    Full Text Available Fishing is one of the oldest occupations, which over the years has gone through several stages. In the economic terms the increase in intensive industrial system of the fish is advantageous because the specific energy consumption is low, given that they not need to maintain body temperature at high temperatures. Having regard to demographic trends in continue increasing, and the tendency of decrease fisheries leads to increased the production of aquaculture fish by order to ensure enough quantity and quality. The purpose of this paper is to highlight the evolution of fish production worldwide and in particular to show the evolution of production of fish from fisheries and aquaculture. To highlight the evolution global fish production given two ways to get fish respectively from aquaculture and fisheries, that have used data from FAOSTAT for 2007-2012. Also we can see that approximately 90% of the fish production is fished in the sea and only 10% in the territorial waters. The fish production in Africa had an ascending trend in the period under review. Analyzing fish production the share of total world continents is noted that Asia has a share of 68% in 2007 and increase to 73% in 2012.

  8. History of glutamate production. (United States)

    Sano, Chiaki


    In 1907 Kikunae Ikeda, a professor at the Tokyo Imperial University, began his research to identify the umami component in kelp. Within a year, he had succeeded in isolating, purifying, and identifying the principal component of umami and quickly obtained a production patent. In 1909 Saburosuke Suzuki, an entrepreneur, and Ikeda began the industrial production of monosodium l-glutamate (MSG). The first industrial production process was an extraction method in which vegetable proteins were treated with hydrochloric acid to disrupt peptide bonds. l-Glutamic acid hydrochloride was then isolated from this material and purified as MSG. Initial production of MSG was limited because of the technical drawbacks of this method. Better methods did not emerge until the 1950s. One of these was direct chemical synthesis, which was used from 1962 to 1973. In this procedure, acrylonitrile was the starting material, and optical resolution of dl-glutamic acid was achieved by preferential crystallization. In 1956 a direct fermentation method to produce glutamate was introduced. The advantages of the fermentation method (eg, reduction of production costs and environmental load) were large enough to cause all glutamate manufacturers to shift to fermentation. Today, total world production of MSG by fermentation is estimated to be 2 million tons/y (2 billion kg/y). However, future production growth will likely require further innovation.

  9. Sicilian potential biogas production

    Directory of Open Access Journals (Sweden)

    Antonio Comparetti


    Full Text Available This study is aimed at predicting the Sicilian potential biogas production, using the Organic Fraction of Municipal Solid Waste (OFMSW, animal manure and food industry by-products, in a region where only one biogas plant using MSW and one co-digestion plant are nowadays available. The statistical data about OFMSW, the number of animals bred in medium and large farms and the amounts of by-products of food processing industries were evaluated, in order to compute the Sicilian potential biogas and energy production. The OFMSW produced in Sicily, that is 0.8 million tons ca. per year (37% of MSW, could be used in a bio-reactor, together with other raw materials, for Anaerobic Digestion (AD process, producing biogas and “digestate”. Moreover, 3.03 million tons ca. of manure, collected in medium and large animal husbandry farms (where cows, pigs and poultry are bred, and 350 thousand tons ca. of by-products, collected in food processing industries (pomace from olive oil mills and grape marc from wineries, might be used for AD process. The Sicilian potential biogas production from the AD of the above raw materials is 170.2 millions of m3, that is equal to 1023.4 GWh of energy per year, of which 484 GWh from animal manure, 303 GWh from OFMSW and 236.4 GWh from food industry by-products. The highest biogas production is in the province of Palermo (35.6 millions of m3, Ragusa (30.8 millions of m3 and Catania (22.8 millions of m3, having a potential energy production of 213.8, 185 and 137 GWh, respectively.

  10. Property Rights and Productivity

    DEFF Research Database (Denmark)

    Newman, Carol; Tarp, Finn; Van Den Broeck, Katleen


    This paper explores the effect of land titling on agricultural productivity in Vietnam and the productivity effects of single versus joint titling for husband and wife. Using a plot-fixed-effects approach our results show that obtaining a land title is associated with higher yields, for both...... individually and jointly held titles. We conclude that there is no tradeoff between joint titling and productivity, and so joint titles are potentially an effective way to improve women’s bargaining power within the household with no associated efficiency losses....

  11. SMART product innovation

    DEFF Research Database (Denmark)

    Cramer-Petersen, Claus L.; Ahmed-Kristensen, Saeema; Li, Xuemeng


    Among the inspirations for the SMART process is “design to customer value,” where products are modified based on a thorough understanding of customers that allows product developers to eliminate features that do not affect customer satisfaction while including only the elements and functionality...... that customers really appreciate. The SMART process includes methods to understand product value for the customer and the user; analyse the cost of components and processes; combine customer value and cost reduction potentials into feasible, high-value concepts; and generate prototypes that can be tested...

  12. Entropy Production of Stars

    Directory of Open Access Journals (Sweden)

    Leonid M. Martyushev


    Full Text Available The entropy production (inside the volume bounded by a photosphere of main-sequence stars, subgiants, giants, and supergiants is calculated based on B–V photometry data. A non-linear inverse relationship of thermodynamic fluxes and forces as well as an almost constant specific (per volume entropy production of main-sequence stars (for 95% of stars, this quantity lies within 0.5 to 2.2 of the corresponding solar magnitude is found. The obtained results are discussed from the perspective of known extreme principles related to entropy production.

  13. Towards sustainable food production

    DEFF Research Database (Denmark)

    Aramyan, Lusine H; Hoste, Robert; van den Broek, Willie


    allocation of pork supply chain activities in Europe. Supply chain production and distribution activities are optimized in various scenarios based on economic and sustainability performance indicators. A mixed integer linear programming (MILP) model, which includes piglet production, fattening, slaughtering......, as minimizing costs will not always lead to an optimal reduction in CO2 equivalent emissions, a differentiated strategy is needed for the European pork sector to move towards more sustainable production......European pork supply chains, like other agri-food supply chains, currently face numerous challenges such as globalization, emerging markets, changing consumer requirements, and new governmental regulations related to issues such as environmental pollution and food safety. These challenges require...

  14. Scheduling for production teams

    Directory of Open Access Journals (Sweden)

    Yuri Mauergauz


    Full Text Available This paper presents a method of calendar (weekly scheduling for production teams, when the average orders utility function is used as the quality criterion. The method is based on the concept of “production intensity”, which is a dynamic parameter of production process. Applied software package allows scheduling for medium quantity of jobs. The result of software application is the team load on the planning horizon. The computed schedule may be corrected and recalculated in interactive mode. Current load of every team is taken into account at each recalculation. The method may be used for any combination of complex and specialized teams.

  15. Production of Metabolites

    DEFF Research Database (Denmark)


    A recombinant micro-organism such as Saccharomyces cerevisiae which produces and excretes into culture medium a stilbenoid metabolite product when grown under stilbenoid production conditions, which expresses in above native levels a ABC transporter which transports said stilbenoid out of said...... micro-organism cells to the culture medium. The genome of the Saccharomyces cerevisiae produces an auxotrophic phenotype which is compensated by a plasmid which also expresses one or more of said enzymes constituting said metabolic pathway producing said stilbenoid, an expression product of the plasmid...

  16. Versioning of printed products (United States)

    Tuijn, Chris


    During the definition of a printed product in an MIS system, a lot of attention is paid to the production process. The MIS systems typically gather all process-related parameters at such a level of detail that they can determine what the exact cost will be to make a specific product. This information can then be used to make a quote for the customer. Considerably less attention is paid to the content of the products since this does not have an immediate impact on the production costs (assuming that the number of inks or plates is known in advance). The content management is typically carried out either by the prepress systems themselves or by dedicated workflow servers uniting all people that contribute to the manufacturing of a printed product. Special care must be taken when considering versioned products. With versioned products we here mean distinct products that have a number of pages or page layers in common. Typical examples are comic books that have to be printed in different languages. In this case, the color plates can be shared over the different versions and the black plate will be different. Other examples are nation-wide magazines or newspapers that have an area with regional pages or advertising leaflets in different languages or currencies. When considering versioned products, the content will become an important cost factor. First of all, the content management (and associated proofing and approval cycles) becomes much more complex and, therefore, the risk that mistakes will be made increases considerably. Secondly, the real production costs are very much content-dependent because the content will determine whether plates can be shared across different versions or not and how many press runs will be needed. In this paper, we will present a way to manage different versions of a printed product. First, we will introduce a data model for version management. Next, we will show how the content of the different versions can be supplied by the customer

  17. Glocalized Production: The Evolution of Global Production

    DEFF Research Database (Denmark)

    Chavez, Marianna; Bilberg, Arne

    production” by key managers of these companies, and test three hypotheses: that a definition could be established from “glocalization” aspects, that it will reduce supply chain complexity, and that it can affect organizational trust levels. The results are presented along with suggestions to pave the way......In light of the challenges of the current globalized production model, four global Danish companies were interviewed with the purpose of exploring “glocalized production” as the new step and solution to the challenges of the “global village.” The research sought to gauge the interest on “glocalized...

  18. Product Life Cycle Planning

    National Research Council Canada - National Science Library

    Walaszek, Jeffrey


    .... This phase of work was undertaken to: (1) provide guidelines, technical support, and planning approaches for researchers that result in realistic life cycle plans for products emerging from the RSM...

  19. Product lifecycle management

    CERN Document Server

    Stark, John


    This third edition updates and adds to the successful second edition and gives the reader a thorough description of PLM, providing them with a full understanding of the theory and the practical skills to implement PLM within their own business environment. This new and expanded edition is fully updated to reflect the many technological and management advances made in PLM since the release of the second edition. Describing the environment in which products are developed, manufactured and supported, before addressing the Five Pillars of PLM: business processes, product data, PLM applications, Organisational Change Management (OCM) and Project Management, this book explains what Product Lifecycle Management is, and why it’s needed. The final part of the book addresses the PLM timeline, showing the typical steps and activities of a PLM project or initiative. “Product Lifecycle Management” will broaden the reader’s understanding of PLM, nurturing the skills needed to implement PLM successfully and to achi...

  20. OSU Chlorophyll Bloom Product (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This product was developed for the Oregon coast based on the observed change between running 8-day composite chlorophyll-a (CHL) data obtained by the MODerate...

  1. Augmented Cellular Meat Production

    DEFF Research Database (Denmark)

    Rehm, Matthias; Philipsen, Mark Philip; Andersen, Rasmus Skovgaard


    The project is focused on a collaborative robot cell concept as an alternative to the serial production line that is currently used in major slaughterhouses. With a robot cell, where a robot and an operator share tasks and workload, we get the strength of the robot and the flexibility...... of the operator. This will help reduce the repetitive stress injuries that plague workers in the industry and it will ease the transition to fully automated robots that can perform the entire process by themselves. The project requires innovation in the way humans and robots collaborate and the development...... of robots that can adapt to the high variation in both products and the interaction with humans. The project contains three labor-intensive cases. The first case, sensing assistance, will visualize information about the product to the operator. The second, robot assistant, will present the product optimally...

  2. Radioactivity in consumer products

    Energy Technology Data Exchange (ETDEWEB)

    Moghissi, A.A.; Paras, P.; Carter, M.W.; Barker, R.F. (eds.)


    Papers presented at the conference dealt with regulations and standards; general and biological risks; radioluminous materials; mining, agricultural, and construction materials containing radioactivity; and various products containing radioactive sources.

  3. Segregation in cast products

    Indian Academy of Sciences (India)


    equiaxed transition ..... solute in a cast product, important ones being: size of casting, rate of solidification, mode of heat extraction ..... the segregated region. A principal breakthrough in quantitative evaluation of segregation distribution has come.

  4. Processed Products Database System (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection of annual data on processed seafood products. The Division provides authoritative advice, coordination and guidance on matters related to the collection,...

  5. Southern pulpwood production, 1961 (United States)

    Vernon L. Robinson; Agnes C. Nichols


    Southern pulpwood production reached 24,230,728 cords in 1961--60 percent of the Nations total. Significant increases were noted in the consumption of hardwood and residues. But pine roundwood remained virtually unchanged for the third consecutive year.

  6. Copyright and product differentiation

    National Research Council Canada - National Science Library

    Yoo, Christopher S


    ... sufficient to support creation of the work. In this Article, Professor Christopher Yoo breaks with the conventional wisdom and proposes a new approach to copyright law based on the economics of product differentiation...

  7. Production competence revisited

    DEFF Research Database (Denmark)

    Szász, Levente; Demeter, Krisztina; Boer, Harry


    Purpose – The purpose of this paper is to seek remedy to two major flaws of the production competence literature, which concern: the way the production competence construct is operationalized and the way its effects on performance are measured. Design/methodology/approach – The paper proposes...... to measure production competence as the two-dimensional operational level construct it actually is, and to use Slack’s (1994) importance performance matrix to study its business level performance effects. The three hypotheses developed are tested using a subsample of the International Manufacturing Strategy...... Survey database, which includes 465 manufacturing companies from 21 countries. Findings – The study offers additional empirical support for production competence theory. Going beyond supporting existing theory, the results give more detailed insight by indicating that low operational performance on even...


    National Research Council Canada - National Science Library

    Miroslava Kacániová; Lubomíra Juhaniaková


    .... and staphylococci were observed. The confectionery products were evaluated: Kremes - honey cube, roll Arabica, roll Rona, roll stuffed with apricot cream, honey cube, pinwheel caramel, Sachovnica cut, Zora cut and curd cake...

  9. Challenges in biogas production

    DEFF Research Database (Denmark)

    Rennuit, Charlotte


    Anaerobic digestion (AnD) is a sustainable process combining waste treatment, nutrient recycling and energy production which can contribute to limit climate change and environmental problems. However, in order for this technique to be more widely used, production of biogas from available wastes...... from a mixture of pig manure and other waste materials by separating the solid fraction of digestate and recycling it back to the digester. It is shown that separation and recycling of the dry matter rich solid fraction could successfully increase biogas production and a preliminary economic evaluation...... showed a potential increase of 1.9 to 6.8€ per ton of biomass treated. In the second part of this study, a biological treatment to improve energy production from wastewater sludge was investigated. Wastewater sludge was subjected to thermophilic aerobic digestion (TAD) from 2h to 5d. Increase in biogas...

  10. Products in fusion systems

    DEFF Research Database (Denmark)

    Henke, Ellen


    We revisit the notion of a product of a normal subsystem with a p-subgroup as defined by Aschbacher (2011) [Asc11, Chapter 8]. In particular, we give a previously unknown, more transparent construction....

  11. Current Icing Product (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Current Icing Product (CIP) is an automatically-generated index suitable for depicting areas of potentially hazardous airframe icing. The CIP algorithm combines...

  12. Smoked Tobacco Products (United States)

    ... cigarette, emphasizing its cool and refreshing taste. In reality, menthol reduces the harshness of cigarette smoke, which ... the use of non-cigarette smoked tobacco products increased dramatically. The largest increases were in use of ...

  13. Food Product Dating (United States)

    ... Standard Forms FSIS United States Department of Agriculture Food Safety and Inspection Service About FSIS District Offices ... Web Content Viewer (JSR 286) Actions ${title} Loading... Food Product Dating "Best if Used By" is a ...

  14. From Environment to Production

    KAUST Repository

    Kodzius, Rimantas


    Using Metagenomic analysis, computational modeling, single cell and genome editing technologies, we are expressing desired microbial genes and their networks in suitable hosts for mass production of energy, food, and fine chemicals

  15. PRODUCTION OF ginger vinegar

    National Research Council Canada - National Science Library

    Leonel, Magali; Suman, Priscila Aparecida; Garcia, Emerson Loli


    Vinegar is a food of condiments group that have great use in the food industry. This study aimed to evaluate the effects of parameters of the acetic fermentation process in the production of ginger vinegar...

  16. Quasidiagonality of crossed products


    Orfanos, Stefanos


    We prove that the crossed product A x G of a separable, unital, quasidiagonal C*- algebra A by a discrete, countable, amenable, maximally almost periodic group G is quasidiagonal, provided that the action is almost periodic.

  17. NSP Production Reports (United States)

    Department of Housing and Urban Development — NSP Production Reports contain cumulative data on units assisted with NSP funds. An NSP grantee reports on the accomplishment of an activity when it meets an End...

  18. Top Production at LHCb

    CERN Multimedia

    Santana Rangel, Murilo


    Single and pair top production in the forward direction at the LHC allows for precision tests of the Standard Model. The observation of top quarks in 7 and 8 TeV data and prospects for precision measurements are shown.

  19. By Product Synergy Analysis (United States)


    AFB developed an environmental management system manual; the manual was prepared according to the ISO 14001 standard. The program is focused on...20 Design for Environment ...................................................................................20 ISO 14000 Series... ISO 14000 Framework ..................................................................................21 Figure 6. By Product Flow

  20. Polyethylene hydroperoxide decomposition products

    National Research Council Canada - National Science Library

    Lacoste, J; Carlsson, David James (Dave); Falicki, S; Wiles, D. M


    The decomposition products from pre-oxidized, linear low-density polyethylene have been identified and quantified for films exposed in the absence of oxygen to ultra-violet irradiation, heat or γ-irradiation...

  1. Genre in media production

    Directory of Open Access Journals (Sweden)

    Hanne Bruun


    Full Text Available How do we explain changes in media genres? Are they the result of economic, technological or other kinds of structural forces; or are they the result of the change-producing agency of the media producers? And how are changes in media texts connected to contextual conditions for media production on micro-, meso- or macro levels? This article suggests that a theoretical approach using a pragmatic and socio-cognitive understanding of genre will help us to address these questions. This approach can highlight the interplay between human agency and different kinds of structural forces involved in specific professional media production cultures. Furthermore, it has the potential to integrate media texts and especially the micro- and meso levels of production. Using lessons learned and findings from my recent production study of Danish television satire, the article will argue three major methodological as well as knowledge-producing advantages of a genre approach.

  2. Peanut Product Recalls (United States)

    U.S. Department of Health & Human Services — This list includes human and pet food subject to recall in the United States since January 2009 related to peanut products distributed by Peanut Corporation of...

  3. Goat production check list

    DEFF Research Database (Denmark)

    Henriksen, Jørgen; Nielsen, Mette Benedicte Olaf; Madsen, Jørgen


    This check list, financed by DanChurchAid, highlights all issues should be carefully investigated before investing in distribution of goats and in interventions to assist poor rural communities to improve their livelihood through goat production.......This check list, financed by DanChurchAid, highlights all issues should be carefully investigated before investing in distribution of goats and in interventions to assist poor rural communities to improve their livelihood through goat production....

  4. Managing Joint Production Motivation

    DEFF Research Database (Denmark)

    Lindenberg, Siegwart; Foss, Nicolai Juul


    We contribute to the microfoundations of organizational performance by proffering the construct of joint production motivation. Under such motivational conditions individuals see themselves as part of a joint endeavor, each with his or her own roles and responsibilities; generate shared...... representations of actions and tasks; cognitively coordinate cooperation; and choose their own behaviors in terms of joint goals. Using goal-framing theory, we explain how motivation for joint production can be managed by cognitive/symbolic management and organizational design....

  5. Production Functions Behaving Badly

    DEFF Research Database (Denmark)

    Fredholm, Thomas

    This paper reconsiders Anwar Shaikh's critique of the neoclassical theory of growth and distribution based on its use of aggregate production functions. This is done by reconstructing and extending Franklin M. Fisher's 1971 computer simulations, which Shaikh used to support his critique. Together...... with other recent extensions to Shaikh's seminal work, my results support and strengthen the evidence against the use of aggregate production functions....

  6. Production of pyrolysis oil



    Methods for fractional catalytic pyrolysis which allow for conversion of biomass into a slate of desired products without the need for post-pyrolysis separation are described. The methods involve use of a fluid catalytic bed which is maintained at a suitable pyrolysis temperature. Biomass is added to the catalytic bed, preferably while entrained in a non-reactive gas such as nitrogen, causing the biomass to become pyrolyzed and forming the desired products in vapor and gas forms, allowing the...

  7. Creating product line architectures


    Bayer, J.; Flege, O.; Gacek, C.


    The creation and validation of product line software architectures are inherently more complex than those of software architectures for single systems. This paper compares a process for creating and evaluating a traditional, one-of-a- kind software architecture with one for a reference software architecture. The comparison is done in the context of PuLSE-DSSA, a customizable process that integrates both product line architecture creation and evaluation.

  8. PRODUCTION OF TRITIUM (United States)

    Jenks, G.H.; Shapiro, E.M.; Elliott, N.; Cannon, C.V.


    This invention relates to a process for the production of tritium by subjecting comminuted solid lithium fluoride containing the lithium isotope of atomic mass number 6 to neutron radiation in a self-sustaining neutronic reactor. The lithium fiuoride is heated to above 450 deg C. in an evacuated vacuum-tight container during radiation. Gaseous radiation products are withdrawn and passed through a palladium barrier to recover tritium. (AEC)

  9. Conditions for industrial production

    DEFF Research Database (Denmark)

    Jensen, Karsten Ingerslev; Schultz, Jørgen Munthe; Brauer, H.


    The possibility of an industrial aerogel glazing production is discussed with respect to sample size, sales volume and prices. Different ways of an industrial assembling line is outlined and the total costs of a 1 square meter aerogel glazing is calculated.......The possibility of an industrial aerogel glazing production is discussed with respect to sample size, sales volume and prices. Different ways of an industrial assembling line is outlined and the total costs of a 1 square meter aerogel glazing is calculated....

  10. Innovativeness in production systems

    DEFF Research Database (Denmark)

    Blichfeldt, Henrik; Knudsen, Mette Præst

    Alignment of market demand and manufacturing capabilities are directly linked to the potential competitive advantage. Pressure for manufacturing companies to customize increase the need for productions systems to handle innovations, especially in SMEs. The paper claims that innovativeness has...... a positive influence of the ability of the manufacturing system to provide specific capabilities that enables the entire production system to positively influence the competitiveness. A comparative case study of three SMEs shows that competitive advantages are obtained through innovative technologies...

  11. Welfare improving product bans


    Doğanoğlu, Uğur Toker; Doganoglu, Ugur Toker; İnceoğlu, Fırat; Inceoglu, Firat


    We formulate a model of vertical differentiation to evaluate the welfare effects of removing a low quality product from the market. The mechanism through which a welfare improvement might arise is simple: Once the low quality low cost alternative is banned, entry into the high quality segment becomes more likely. This in turn may lead to a significant reduction in the price of the high quality product. We find that such a ban might improve aggregate welfare when consumers value the higher qua...

  12. Pretreated densified biomass products (United States)

    Dale, Bruce E; Ritchie, Bryan; Marshall, Derek


    A product comprising at least one densified biomass particulate of a given mass having no added binder and comprised of a plurality of lignin-coated plant biomass fibers is provided, wherein the at least one densified biomass particulate has an intrinsic density substantially equivalent to a binder-containing densified biomass particulate of the same given mass and h a substantially smooth, non-flakey outer surface. Methods for using and making the product are also described.

  13. New products in risk management : integrated products

    Energy Technology Data Exchange (ETDEWEB)

    Bagby, M. [Aon Reed Stenhouse, Calgary, AB (Canada)


    The issue of integrated risk in the insurance sector of the financial services industry was discussed. The concept of integrated risk is based on the fact that there are efficiencies to be gained by aggregating risk through time. The presentation focuses on the renewed interest in integrated risk management that addresses the corporation`s entire portfolio of risks and attempts to seek out single source solutions which allow the portfolio of risks to be retained, transferred or financed over time in a productive manner. The insurance sector`s response to supplying the demand for integrated risk solutions by the energy industry is outlined. Guidelines for creating an integrated risk program are also provided.

  14. Perspectives in production of functional meat products (United States)

    Vasilev, D.; Glišić, M.; Janković, V.; Dimitrijević, M.; Karabasil, N.; Suvajdžić, B.; Teodorović, V.


    The meat industry has met new challenges since the World Health Organization classified processed meat in carcinogenic Group 1. In relation to this, the functional food concept in meat processing has gained importance, especially in reducing carcinogenic N-nitroso compounds and polycyclic aromatic hydrocarbons (PAHs) as an additional imperative, apart from the usual fat and salt reduction and product enrichment with functional ingredients. PAH reduction relies on control of the smoking process, but there is also a possibility they could be degraded by means of probiotic microorganisms or spices. The reduction of N-nitroso compounds could be provided by lowering the amount of added nitrite/nitrate, using substitutes for these chemicals, and/or by preventing conditions for the creation of N-nitroso compounds. Nevertheless, fat and salt reductions still remain topical, and rely mostly on the use of functional ingredients as their substitutes.

  15. Biodiesel production technologies: review

    Directory of Open Access Journals (Sweden)

    Shemelis Nigatu Gebremariam


    Full Text Available Biodiesel is a fuel with various benefits over the conventional diesel fuel. It is derived from renewable resources, it has less emission to environment, it is biodegradable so has very limited toxicity and above all its production can be decentralized so that it could have a potential in helping rural economies. However, there are also some worth mentioning challenges associated with production of biodiesel. Among them repeatedly mentioned are the cost of feedstock and the choice of convenient technology for efficient production of the fuel from diverse feedstock types. There are four main routes by which raw vegetable oil and/or animal fat can be made suitable for use as substituent fuel in diesel engines without modification. These are direct use or blending of oils, micro-emulsion, thermal cracking or pyrolysis and transesterification reaction. Due to the quality of the fuel produced, the transesterification method is the most preferred way to produce biodiesel from diverse feedstock types. Through this method, oils and fats (triglycerides are converted to their alkyl esters with reduced viscosity to near diesel fuel levels. There are different techniques to carry out transesterification reaction for biodiesel production. Each technique has its own advantages and disadvantages as well as its own specifically convenient feedstock character. There are also some very important reaction conditions to be given due attention in each of this techniques for efficient production of biodiesel, such as molar ratio of alcohol to oil, type and amount of catalyst, reaction temperature, reaction time, reaction medium, type and relative amount of solvents, among others. This review is meant to investigate the main transesterification techniques for biodiesel production in terms of their choice of feedstock character as well as their determinately required reaction conditions for efficient biodiesel production, so that to give an overview on their advantages

  16. Product Knowledge Modelling and Management

    DEFF Research Database (Denmark)

    Zhang, Y.; MacCallum, K. J.; Duffy, Alex


    The term, Product Knowledge is used to refer to two related but distinct concepts; the knowledge of a specific product (Specific Product Knowledge) and the knowledge of a product domain (Product Domain Knowledge). Modelling and managing Product Knowlege is an essential part of carrying out design...... function-oriented design. Both Specific Product Knowledge and Product Domain Knowledge are modelled at two levels, a meta-model and an information-level.Following that, a computer-based scheme to manage the proposed product lknowledge models within a dynamically changing environment is presented........A scheme is presented in this paper to model, i.e. classify, structure and formalise the product knowledge for the purpose of supporting function-oriented design. The product design specification and four types of required attributes of a specific product have been identified to form the Specific Product...

  17. Product mix retail strategies

    Directory of Open Access Journals (Sweden)

    Ristić Miloš


    Full Text Available The sales of appropriate merchandise is essential for performance of every retail enterprise. The way that products are displayed within retail sales object will be in so much important as the merchandise is considered a pad of the perceived image of that outlet. Thus, assorted products speak to their consumers as far as to what they [the consumers] can expect, and they signal off a number of marketing messages as well. Merchandising is the key element in attracting the consumers and in encouraging of repeated purchases. The question then could be: products or services?, yet the retailer's future will depend on his ability to develop the best sale offers. The selection of appropriate merchandise, and that would be the one [merchandise] that is in accordance with outlet's image, requires careful planning which, again, needs to be related with the direction the seller is following. Managing of the product assortments' dimensions emerges from the retailer's strategic planning, therefore, the decisions made on the inclusion of novel products as well as about deleting of the old stock are deemed (to be strategic.

  18. Patent and product piracy (United States)

    Ignat, V.


    Advanced industrial countries are affected by technology theft. German industry annually loses more than 50 billion euros. The main causes are industrial espionage and fraudulent copying patents and industrial products. Many Asian countries are profiteering saving up to 65% of production costs. Most affected are small medium enterprises, who do not have sufficient economic power to assert themselves against some powerful countries. International organizations, such as Interpol and World Customs Organization - WCO - work together to combat international economic crime. Several methods of protection can be achieved by registering patents or specific technical methods for recognition of product originality. They have developed more suitable protection, like Hologram, magnetic stripe, barcode, CE marking, digital watermarks, DNA or Nano-technologies, security labels, radio frequency identification, micro color codes, matrix code, cryptographic encodings. The automotive industry has developed the method “Manufactures against Product Piracy”. A sticker on the package features original products and it uses a Data Matrix verifiable barcode. The code can be recorded with a smartphone camera. The smartphone is connected via Internet to a database, where the identification numbers of the original parts are stored.

  19. New Product Launching Ideas (United States)

    Kiruthika, E.


    Launching a new product can be a tense time for a small or large business. There are those moments when you wonder if all of the work done to develop the product will pay off in revenue, but there are many things are can do to help increase the likelihood of a successful product launch. An open-minded consumer-oriented approach is imperative in todayís diverse global marketplace so a firm can identify and serve its target market, minimize dissatisfaction, and stay ahead of competitors. Final consumers purchase for personal, family, or household use. Finally, the kind of information that the marketing team needs to provide customers in different buying situations. In high-involvement decisions, the marketer needs to provide a good deal of information about the positive consequences of buying. The sales force may need to stress the important attributes of the product, the advantages compared with the competition; and maybe even encourage ìtrialî or ìsamplingî of the product in the hope of securing the sale. The final stage is the post-purchase evaluation of the decision. It is common for customers to experience concerns after making a purchase decision. This arises from a concept that is known as ìcognitive dissonance

  20. Gestion de production

    CERN Document Server

    Courtois, Alain; Pillet, Maurice


    n ouvrage de référence pour tous les gestionnaires de production industrielle. Un cas concret d'entreprise fictive, fil rouge de l'ouvrage, pour expliquer et illustrer les différents outils et méthodes utilisés. Toutes les méthodes et tous les outils de gestion de production, des plus traditionnels aux novateurs, explicités, comparés et illustrés. L'ouvrage, entièrement mis à jour, reflète toutes les évolutions liées à la gestion de production. II se divise désormais en deux grandes partes ; la première regroupe les méthodes de base de la gestion de la production ainsi que l'informatisation de celles-ci (chapitres 2 à 10) ; la seconde concerne les méthodes d'amélioration de la production (chapitres 11 à 15), en mettant un accent fort sur la philosophie du Lean Manufacturing : L'entreprise en mouvement avec le Lean ; Les principaux outils du Lean ; Le pilotage d'atelier en flux tirés par la méthode Kanban ; L'implantation d'ateliers ; Les indicateurs de performance. Pour faciliter la le...

  1. Smoke production in fires

    Energy Technology Data Exchange (ETDEWEB)

    Sarvaranta, L.; Kokkala, M. [VTT Building Technology, Espoo (Finland). Building Physics, Building Services and Fire Technology


    Characterization of smoke, factors influencing smoke production and experimental methods for measuring smoke production are discussed in this literature review. Recent test-based correlation models are also discussed. Despite the large number of laboratories using different fire testing methods, published smoke data have been scarce. Most technical literature on smoke production from building materials is about experimental results in small scale tests. Compilations from cone calorimeter tests have been published for a few materials, e.g. upholstered furniture materials and some building products. Mass optical density data and compilations of gravimetric soot data are available for various materials as well as a number of smoke obscuration values. For a given material often a wide range of values of smoke output can be found in the literature and care should be exercised in applying the appropriate value in each case. In laboratory experiments, the production of smoke and its optical properties are often measured simultaneously with other fire properties as heat release and flame spread. The measurements are usually dynamic in full scale, i.e. they are performed in a flow-through system. In small scale they may be either dynamic, as in the cone calorimeter, or static, i.e. the smoke is accumulated in a closed box. Small-scale tests are necessary as practical tools. Full-scale tests are generally considered to be more reliable and are needed to validitate the small-scale tests

  2. Application of manufactured products (United States)

    Sastri, Sankar; Duke, Michael B.

    A wide range of products can be manufactured from the following materials: (1) lunar regolith or basalt; (2) regolith or rock beneficiated to concentrate plagioclase or other minerals; (3) iron, extracted from lunar soil or rocks by various means; (4) naturally occurring or easily obtained materials that have cementitious properties; and (5) byproducts of the above materials. Among the products that can be produced from these materials are the following: beams; plates and sheets; transparent plates (windows); bricks and blocks; pipes and tubes; low-density materials (foams); fiber, wire, and cables; foils and reflective coatings; hermetic seals (coatings); and formed objects. In addition to oxygen, which can be obtained by several processes, either from unbeneficiated regolith or by reduction of concentrated ilmenite, these materials make the simplest requirements of the lunar resource extraction system. A thorough analysis of the impact of these simplest products on the economics of space operations is not possible at this point. Research is necessary both to define optimum techniques and adapt them to space and to determine the probable market for the products so that the priority of various processes can be assessed. Discussions of the following products are presented: aerobraking heat shields; pressurized habitats; lunar photovoltaic farms; and agricultural systems.

  3. Product versus Process: Innovation Strategies of Multi-Product Firms


    Flach, Lisandra; Irlacher, Michael


    This paper studies the innovation strategies of multi-product firms in industries with different scope for product differentiation. In a simple model of multi-product firms, we show that returns to product versus process innovation are industry-specific. Demand and cost linkages induce a natural distinction between the returns to product and process innovation. In highly differentiated industries, the cannibalization effect is lower and, therefore, firms invest more in product innovation. In ...

  4. An Optimization Model for Product Placement on Product Listing Pages


    Yan-Kwang Chen; Fei-Rung Chiu; Ciao-Jyun Yang


    The design of product listing pages is a key component of Website design because it has significant influence on the sales volume on a Website. This study focuses on product placement in designing product listing pages. Product placement concerns how venders of online stores place their products over the product listing pages for maximization of profit. This problem is very similar to the offline shelf management problem. Since...

  5. Natural products in endodontics. (United States)

    Almadi, Ebtissam M; Almohaimede, Amal A


    Herbal remedies are used throughout the world, either in earlier or in recent times. The number of studies on this alternative therapeutic system increased in the last decades. In this paper, the relevant literature on the use of natural products in root canal therapy is revised from a MEDLINE database search. The uses of medicinal plants in endodontics include cleaning and disinfection of root canals, intracanal medicaments between appointments, sealer cements, and for removal of obturation material. Other studies showed the effect of natural products in pulpal and dentin repair. Their use is anecdotal, and their effectiveness showed to be variable and is always compared to the chemical standards currently being used. Alkaloids, coumarins, saponins, and flavonoids are aromatic substances that are produced by plants and evaluated for their therapeutic potential. Further investigation into benefits of natural products is warranted.


    Directory of Open Access Journals (Sweden)

    Catalin Mihail BARBU


    Full Text Available In this paper I discussed the factors that influence the cultural adaptation ofproducts. Globalization determines the companies to operate abroad;therefore the firms sell their products to markets where the consumerpatterns might differ from their national market. It is of high importance to beable to understand and to adapt to local consumer habits. The culture has astrong influence on products adaptation in particular, and on internationalmarketing in general. Companies must be able to adapt their products, but, inthe same time, to keep the note of originality, so that the global image ofbrand to gain consistency. Global brands provide a larger advantageregarding the marketing activities and costs. Savy companies are capable torecognize and to use cultural differences in their use.

  7. ATLAS production system

    CERN Document Server

    Borodin, Mikhail; The ATLAS collaboration; De, Kaushik; Klimentov, Alexei; Golubkov, Dmitry; Maeno, Tadashi; Mashinistov, Ruslan; Wenaus, Torre; Padolski, Siarhei


    The second generation of the ATLAS production system called ProdSys2 is a distributed workload manager which used by thousands of physicists to analyze the data remotely, with the volume of processed data is beyond the exabyte scale, across a more than hundred heterogeneous sites. It achieves high utilization by combining dynamic job definition based on many criterias, such as input and output size, memory requirements and CPU consumption with manageable scheduling policies and by supporting different kind of computational resources, such as GRID, clouds, supercomputers and volunteering computers. Besides jobs definition Production System also includes flexible web user interface, which implements user-friendly environment for main ATLAS workflows, e.g. simple way of combining different data flows, and real-time monitoring, optimised for using with huge amount of information to present. We present an overview of the ATLAS Production System major components: job and task definition, workflow manager web user i...

  8. Renewable Acrylonitrile Production

    Energy Technology Data Exchange (ETDEWEB)

    Beckham, Gregg T [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Karp, Eric M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Eaton, Todd R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sanchez i Nogue, Violeta [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Vorotnikov, Vassili [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Biddy, Mary J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Tan, Eric C [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Brandner, David [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Manker, Lorenz [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Michener, William E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Vardon, Derek R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bratis, Adam D [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Liu, Rongming [University of Colorado; Gill, Ryan T. [University of Colorado; Gilhespy, Michelle [Johnson Matthey Technology Centre; Skoufa, Zinovia [Johnson Matthey Technology Centre; Watson, Michael J. [Johnson Matthey Technology Centre; Fruchey, O. Stanley [MATRIC; Cywar, Robin M. [Formerly NREL


    Acrylonitrile (ACN) is a petroleum-derived compound used in resins, polymers, acrylics, and carbon fiber. We present a process for renewable ACN production using 3-hydroxypropionic acid (3-HP), which can be produced microbially from sugars. The process achieves ACN molar yields exceeding 90% from ethyl 3-hydroxypropanoate (ethyl 3-HP) via dehydration and nitrilation with ammonia over an inexpensive titanium dioxide solid acid catalyst. We further describe an integrated process modeled at scale that is based on this chemistry and achieves near-quantitative ACN yields (98 +/- 2%) from ethyl acrylate. This endothermic approach eliminates runaway reaction hazards and achieves higher yields than the standard propylene ammoxidation process. Avoidance of hydrogen cyanide as a by-product also improves process safety and mitigates product handling requirements.

  9. Product and Process Modelling

    DEFF Research Database (Denmark)

    Cameron, Ian T.; Gani, Rafiqul

    to biotechnology applications, food, polymer and human health application areas. The book highlights to important nature of modern product and process modelling in the decision making processes across the life cycle. As such it provides an important resource for students, researchers and industrial practitioners.......This book covers the area of product and process modelling via a case study approach. It addresses a wide range of modelling applications with emphasis on modelling methodology and the subsequent in-depth analysis of mathematical models to gain insight via structural aspects of the models....... These approaches are put into the context of life cycle modelling, where multiscale and multiform modelling is increasingly prevalent in the 21st century. The book commences with a discussion of modern product and process modelling theory and practice followed by a series of case studies drawn from a variety...

  10. Production of cyclotron radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Yong Sup; Lim, Sang Moo; Yang, Seung Dae; Chun, Kwon Soo; Ahn, Soon Hyuk; Yun, Yong Kee; Park, Hyun; Lee, Ji Sup; Lee, Jong Doo; Chai, Jong Seo; Kim, Yoo Seok; Hong, Sung Suk; Lee, Min Yong; Beak, Seung Ki [Korea Cancer Center Hospital, Seoul (Korea)


    In the project, 11,492mCi of {sup 201}Tl, 4,384mCi of {sup 67}Ga, 1,245mCi of {sup 123}l, 523mCi of [{sup 123}I]mlBG and 1,283mCi of {sup 18}FDG were supplied, and the revenue were 304,723,000won. In the production of RI, 13 deg for {sup 201}Tl and {sup 67}Ga, 45 deg for {sup 123}l angle solid target have been used, and liquid target system has been used for {sup 18}F production. For the efficient use of the cyclotron, the MC-50 cyclotron was opened to outside user and basic research project was carried out. The technical supports and radionuclides analysis were done during the execution of the research. Then the facilities of safety supervision and handling techniques of radioisotope production were improved. 7 refs., 9 figs., 8 tabs. (Author)

  11. Production of cyclotron radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Kwon Soo; Lim, Sang Moo; Yang, Seung Dae; Suh, Yong Sup; Ahn, Soon Hyuk; Yun, Yong Kee; Park, Hyun; Lee, Ji Sup; Chai, Jong Seo; Kim, Yoo Seok; Hong, Sung Suk; Lee, Min Yong; Beak, Seung Ki; Kim, Jang Hye; Kim, Gi Sup [Korea Cancer Center Hospital, Seoul (Korea)


    In the project, 12,077mCi of {sup 201}Tl, 5,717mCi of {sup 67}Ga, 2,096mCi of {sup 123}l, 482mCi of [{sup 123}I]mlBG and 2,738mCi of {sup 18}FDG were supplied, and the revenue were 387,253,000won. In the production of RI, 13 deg for {sup 201}Tl and {sup 67}Ga, 45 deg for {sup 123}l angle solid target have been used, and liquid target system has been used for {sup 18}F production. For the efficient use of the cyclotron, the MC-50 cyclotron was opened to outside user and basic research project was carried out. The technical supports and radionuclides analysis were done during the execution of the research. Then the facilities of safety supervision and handling techniques of radioisotope production were improved. 7 refs., 8 figs., 9 tabs. (Author)

  12. Additives in yoghurt production

    Directory of Open Access Journals (Sweden)

    Milna Tudor


    Full Text Available In yoghurt production, mainly because of sensory characteristics, different types of additives are used. Each group, and also each substance from the same group has different characteristics and properties. For that reason, for improvement of yoghurt sensory characteristics apart from addition selection, the quantity of the additive is very important. The same substance added in optimal amount improves yoghurt sensory attributes, but too small or too big addition can reduce yoghurt sensory attributes. In this paper, characteristics and properties of mostly used additives in yoghurt production are described; skimmed milk powder, whey powder, concentrated whey powder, sugars and artificial sweeteners, fruits, stabilizers, casein powder, inulin and vitamins. Also the impact of each additive on sensory and physical properties of yoghurt, syneresis and viscosity, are described, depending on used amount added in yoghurt production.


    Directory of Open Access Journals (Sweden)

    Jolana Karovičová


    Full Text Available The aim of this work was to write down a review article about various aspects connected with staling of bakery products. Shelf life is directly associated with the staling process, which depends on the composition of bakery products and important are storage conditions as well. In the article are described particular components (starch, nonstarch polysacharides, water and how they affect the staling process. Generally during staling of bakery products occur  processes related with starch retrogradation, moisture redistribution from the crumb to the crust and other interactions between components. Staling process could be delayed by using various bakery improvers like enzymes, hydrocolloids, emulgators and other compounds. Also useful is the application of suitable packaging techniques.doi:10.5219/124

  14. Antiplasmodial Natural Products

    Directory of Open Access Journals (Sweden)

    Cláudio R. Nogueira


    Full Text Available Malaria is a human infectious disease that is caused by four species of Plasmodium. It is responsible for more than 1 million deaths per year. Natural products contain a great variety of chemical structures and have been screened for antiplasmodial activity as potential sources of new antimalarial drugs. This review highlights studies on natural products with antimalarial and antiplasmodial activity reported in the literature from January 2009 to November 2010. A total of 360 antiplasmodial natural products comprised of terpenes, including iridoids, sesquiterpenes, diterpenes, terpenoid benzoquinones, steroids, quassinoids, limonoids, curcubitacins, and lanostanes; flavonoids; alkaloids; peptides; phenylalkanoids; xanthones; naphthopyrones; polyketides, including halenaquinones, peroxides, polyacetylenes, and resorcylic acids; depsidones; benzophenones; macrolides; and miscellaneous compounds, including halogenated compounds and chromenes are listed in this review.

  15. Accessibility and assistive products (United States)

    Rodríguez-Porrero, Cristina


    Introduction Accessibility and assistive products and technologies are needed to ensure the rights of persons with disabilities and older persons. Many developments have been implemented in laws, standards, markets and from the consumers perspective, at international, European and national levels. The real issue is that not all the potential users benefit from the use of assistive products or accessible measures. Discussion Innovative methods are needed to allow all potential users to have real advantage of assistive technologies and accessible and design for all facilities. Best practices will be presented and existing gaps and recommendations will be discussed. Cost-benefits aspects will also be presented. Conclusion In order to get advantages from opportunities of globalization, hard work and responsibilities of all stakeholders are needed, so that assistive products and accessibility reach a whole range of situations and environments and contribute to ensure quality of life in a society for all.

  16. Energy production systems engineering

    CERN Document Server

    Blair, Thomas Howard


    Energy Production Systems Engineering presents IEEE, Electrical Apparatus Service Association (EASA), and International Electrotechnical Commission (IEC) standards of engineering systems and equipment in utility electric generation stations. Electrical engineers that practice in the energy industry must understand the specific characteristics of electrical and mechanical equipment commonly applied to energy production and conversion processes, including the mechanical and chemical processes involved, in order to design, operate and maintain electrical systems that support and enable these processes. To aid this understanding, Energy Production Systems Engineeringdescribes the equipment and systems found in various types of utility electric generation stations. This information is accompanied by examples and practice problems. It also addresses common issues of electrical safety that arise in electric generation stations.

  17. Renewable acrylonitrile production. (United States)

    Karp, Eric M; Eaton, Todd R; Sànchez I Nogué, Violeta; Vorotnikov, Vassili; Biddy, Mary J; Tan, Eric C D; Brandner, David G; Cywar, Robin M; Liu, Rongming; Manker, Lorenz P; Michener, William E; Gilhespy, Michelle; Skoufa, Zinovia; Watson, Michael J; Fruchey, O Stanley; Vardon, Derek R; Gill, Ryan T; Bratis, Adam D; Beckham, Gregg T


    Acrylonitrile (ACN) is a petroleum-derived compound used in resins, polymers, acrylics, and carbon fiber. We present a process for renewable ACN production using 3-hydroxypropionic acid (3-HP), which can be produced microbially from sugars. The process achieves ACN molar yields exceeding 90% from ethyl 3-hydroxypropanoate (ethyl 3-HP) via dehydration and nitrilation with ammonia over an inexpensive titanium dioxide solid acid catalyst. We further describe an integrated process modeled at scale that is based on this chemistry and achieves near-quantitative ACN yields (98 ± 2%) from ethyl acrylate. This endothermic approach eliminates runaway reaction hazards and achieves higher yields than the standard propylene ammoxidation process. Avoidance of hydrogen cyanide as a by-product also improves process safety and mitigates product handling requirements. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  18. Product Platform Performance

    DEFF Research Database (Denmark)

    Munk, Lone

    , and the subject has gained increased attention in industry and academia the past decade. Literature on platform-based product development is often based on single case studies and it is sparsely verified if expected effects are achieved. This makes it difficult to put forward realistic expectations for companies...... experienced representatives from the different life systems phase systems of the platform products. The effects are estimated and modeled within different scenarios, taking into account financial and real option aspects. The model illustrates and supports estimation and quantification of internal platform...... effects. The model empirically verifies findings in literature and received moderate support from industry in the validation study. The research findings document that product platforms achieve significant internal effects in terms of • reduced development time (often around 25 %), • reduced number...


    Directory of Open Access Journals (Sweden)

    KESKIN Reyhan


    Full Text Available Nanofibers are very thin fibers having diameters lower than 100 nm and their lengths might be as long as possible within production limits. The large surface area of nanofibers gives opportunity to functionalize them. Nanofibers have several applications including both applications for industrial production in many sectors and for research studies. Nanofibers find applications in energy devices such as solar cells, fuel cells and nanogenarators; in filtration applications (such as water/oil filtration, fine particle filtration, aerosol filtration, air filtration, nanoparticle filtration and in several medical applications including antibacterial efficacy, wound healing, drug delivery and scaffolds for tissue engineering. There are several methods to produce nanofibers: Electrospinning, self assembly, phase separation, bacterial cellulose, templating, drawing, extraction, vapor-phase polymerization, kinetically controlled solution synthesis, conventional chemical polymerization for anyline. Electrospinning is the most widely used method to produce nanofibers.In electrospinning, a high electric field, which is in kilovolts, is applied to a polymer solution. The polymer solution is drawn from a syringe to a collector surface.Electrospinning requires usage of appropriate solvent, removal of evaporating solvent, an adequate power supply to overcome the viscosity and surface tension of the polymer solution; while, jet instability and jet control remain as challenges in electrospinning. Nanofiber production methods possess some disadvantages as: higher cost compared to conventional fiber production methods, health hazards such as inhale risk of nanofibers during production and keeping the environment safe from evaporating solvents used during nanofiber production. Up to date, many researches have been conducted on nanofibers and electrospinning; still, more controllable, more cost effective, more environmentally friendly and safer methods are of

  20. Transdisciplinary product development

    Directory of Open Access Journals (Sweden)

    Tomaž Savšek


    Full Text Available Research Question (RQ: How can transdisciplinary approach increase the product development process in future industry? Purpose: The aim of the research is to develop a model of an effective product development in the automotive industry based on the transdisciplinary approach. Method: We used a qualitative research approach in order to develop a theoretical framework of transdisciplinarity. The framework comprises the concurrent engineering and experts from different disciplines. The framework was represented by a mathematical model which based on stochastic dynamic programming. Results: We developed a theoretical frameworkand a practical case of transdisciplinary product development in the automotive industry. We presented a mathematical model and information environment which supports such a model. Organization: The findings of the research will provide higher productivity, lower operating costs, change in personnel structure, higher added value, lower sales costs, lower administration costs, reduction in growth of expenses, and lower costs of work equipment. Society: The research impact on higher customer’s satisfaction, increased flexibility of operations, better quality of information, improved control of sources, less waste materials and less pollution, improved planning process, more favourable consideration of employees , improved portfolio management, and better corporate presentation of company. Originality: Transdisciplinary framework combines methods of concurrent engineering and interdisciplinary approach in a process of product development. The development of such a framework is a complete novelty and represents an original approach to product development, which will be particularly suitable for the smart factories of the future. Transdisciplinary framework was transformed in to a mathematical model based on stochastic dynamic programming. Model is supported by the existing information warehouse and represents a potential for