Photo-induced luminescence

The present paper is a critical review dealing with the characteristics, reaction mechanisms and photoproducts, instrumentation and analytical applications of the photo-induced either chemiluminescence or fluorescence. Special attention is paid to the determination of pesticides by continuous-flow methodologies. The paper is divided into several sections covering the most relevant published papers.Catalá Icardo, M.; Martínez Calatayud, JM. (2008). Photo-induced luminescence. Critical Reviews in Analytical Chemistry. 38(2):118-130. doi:10.1080/10408340802039609S118130382Lukasiewicz, R. J., & Fitzgerald, J. M. (1973). Digital integration method for fluorimetric studies of photochemically unstable compounds. Analytical Chemistry, 45(3), 511-517. doi:10.1021/ac60325a002Aaron, J. J., Villafranca, J. E., White, V. R., & Fitzgerald, J. M. (1976). A Quantitative Photochemical-Fluorimetric Method for Measurement of Nonfluorescent Vitamin K1. Applied Spectroscopy, 30(2), 159-162. doi:10.1366/000370276774456408Coly, A., & Aaron, J.-J. (1998). Fluorimetric analysis of pesticides: Methods, recent developments and applications. Talanta, 46(5), 815-843. doi:10.1016/s0039-9140(97)00366-4Aaron, J.-J., & Coly, A. (2000). Luminescence methods in pesticide analysis. Applications to the environment. Analusis, 28(8), 699-709. doi:10.1051/analusis:2000280699Catalá Icardo, M., Garcı́a Mateo, J. V., & Martı́nez Calatayud, J. (2002). Multicommutation as a powerful new analytical tool. TrAC Trends in Analytical Chemistry, 21(5), 366-378. doi:10.1016/s0165-9936(02)00505-8Coly, A. (1999). Photochemically-induced fluorescence determination of sulfonylurea herbicides using micellar media. Talanta, 49(1), 107-117. doi:10.1016/s0039-9140(98)00349-xWerkhoven-Goewie, C. E., Boon, W. M., Praat, A. J. J., Frei, R. W., Brinkman, U. A. T., & Little, C. J. (1982). Preconcentration and LC analysis of chlorophenols, using a styrene-divinyl-benzene copolymeric sorbent and photochemical reaction detection. Chromatographia, 16(1), 53-59. doi:10.1007/bf02258869Scholten, A. H. M. T., Welling, P. L. M., Brinkman, U. A. T., & Frei, R. W. (1980). Use of PTFE coils in post-column photochemical reactors for liquid chromatograph — application to pharmaceuticals. Journal of Chromatography A, 199, 239-248. doi:10.1016/s0021-9673(01)91376-7Batley, G. E. (1984). Use of Teflon components in photochemical reactors. Analytical Chemistry, 56(12), 2261-2262. doi:10.1021/ac00276a066Engelhardt, H., & Neue, U. D. (1982). Reaction detector with three dimensional coiled open tubes in HPLC. Chromatographia, 15(7), 403-408. doi:10.1007/bf02261598Coly, A., & Aaron, J.-J. (1994). Photochemical–spectrofluorimetric method for the determination of several aromatic insecticides. The Analyst, 119(6), 1205-1209. doi:10.1039/an9941901205ALBERTGARCIA, J., ICARDO, M., & CALATAYUD, J. (2006). Analytical strategy photodegradation/chemiluminescence/continuous-flow multicommutation methodology for the determination of the herbicide Propanil. Talanta, 69(3), 608-614. doi:10.1016/j.talanta.2005.10.044Coly, A., & Aaron, J.-J. (1998). Cyclodextrin-enhanced fluorescence and photochemically-induced fluorescence determination of five aromatic pesticides in water. Analytica Chimica Acta, 360(1-3), 129-141. doi:10.1016/s0003-2670(97)00721-6Poulsen, J. B., Birks, K. S., Gandelman, M. S., & Birks, J. W. (1986). Crocheted PTFE reactors for post-column photochemistry in HPLC. Chromatographia, 22(7-12), 231-234. doi:10.1007/bf02268764Martínez Calatayud, J. 1988.Flow Injection Analysis of Pharmaceuticals. Automation in the Laboratory, 458London, UK: Taylor and Francis Ltd.Palomeque, M., Garcı́a Bautista, J. ., Catalá Icardo, M., Garcı́a Mateo, J. ., & Martı́nez Calatayud, J. (2004). Photochemical-chemiluminometric determination of aldicarb in a fully automated multicommutation based flow-assembly. Analytica Chimica Acta, 512(1), 149-156. doi:10.1016/j.aca.2004.02.031Chivulescu, A., Catalá-Icardo, M., Garcı́a Mateo, J. ., & Martı́nez Calatayud, J. (2004). New flow-multicommutation method for the photo-chemiluminometric determination of the carbamate pesticide asulam. Analytica Chimica Acta, 519(1), 113-120. doi:10.1016/j.aca.2004.05.046PAWLICOVÁ, Z., ALBERT-GARCÍA, J. R., SAHUQUILLO, I., GARCÍA MATEO, J. V., CATALÁ ICARDO, M., & MARTÍNEZ CALATAYUD, J. (2006). Chemiluminescent Determination of the Pesticide Bromoxynil by On-line Photodegradation in a Flow-Injection System. Analytical Sciences, 22(1), 29-34. doi:10.2116/analsci.22.29Mervartová, K., Calatayud, J. M., & Icardo, M. C. (2005). A Fully Automated Assembly Using Solenoid Valves for the Photodegradation and Chemiluminometric Determination of the Herbicide Chlorsulfuron. Analytical Letters, 38(1), 179-194. doi:10.1081/al-200043477Coly, A., & Aaron, J.-J. (1999). Sensitive and rapid flow injection analysis of sulfonylurea herbicides in water with micellar-enhanced photochemically induced fluorescence detection. Analytica Chimica Acta, 392(2-3), 255-264. doi:10.1016/s0003-2670(99)00229-9Garcı́a-Campaña, A. M., Aaron, J.-J., & Bosque-Sendra, J. M. (2001). Micellar-enhanced photochemically induced fluorescence detection of chlorophenoxyacid herbicides. Flow injection analysis of mecoprop and 2,4-dichlorophenoxyacetic acid. Talanta, 55(3), 531-539. doi:10.1016/s0039-9140(01)00470-2Parrilla�V�zquez, P., Gil�Garc�a, M. D., Barranco�Mart�nez, D., & Mart�nez�Galera, M. (2005). Application of coupled-column liquid chromatography combined with post-column photochemically induced fluorimetry derivatization and fluorescence detection to the determination of pyrethroid insecticides in vegetable samples. Analytical and Bioanalytical Chemistry, 381(6), 1217-1225. doi:10.1007/s00216-004-3043-xIrace-Guigand, S., Leverend, E., Seye, M. D. G., & Aaron, J. J. (2005). A new on-line micellar-enhanced photochemically-induced fluorescence method for determination of phenylurea herbicide residues in water. Luminescence, 20(3), 138-142. doi:10.1002/bio.817Liu, L., & Guo, Q.-X. (2002). Journal of Inclusion Phenomena and Macrocyclic Chemistry, 42(1/2), 1-14. doi:10.1023/a:1014520830813Frankewich, R. P., Thimmaiah, K. N., & Hinze, W. L. (1991). Evaluation of the relative effectiveness of different water-soluble .beta.-cyclodextrin media to function as fluorescence enhancement agents. Analytical Chemistry, 63(24), 2924-2933. doi:10.1021/ac00024a023Patel, B. M., Moye, H. A., & Weinberger, R. (1991). Postcolumn formation of fluorophores from nitrogenous pesticides by UV photolysis. Talanta, 38(8), 913-922. doi:10.1016/0039-9140(91)80272-2Torrents, A., Anderson, B. G., Bilboulian, S., Johnson, W. E., & Hapeman, C. J. (1997). Atrazine Photolysis:  Mechanistic Investigations of Direct and Nitrate-Mediated Hydroxy Radical Processes and the Influence of Dissolved Organic Carbon from the Chesapeake Bay. Environmental Science & Technology, 31(5), 1476-1482. doi:10.1021/es9607289Dogliotti, L., & Hayon, E. (1967). Flash photolysis of per[oxydi]sulfate ions in aqueous solutions. The sulfate and ozonide radical anions. The Journal of Physical Chemistry, 71(8), 2511-2516. doi:10.1021/j100867a019Pérez-Ruiz, T. (2001). Flow injection determination of methamidophos using online photo-oxidation and fluorimetric detection. Talanta, 54(5), 989-995. doi:10.1016/s0039-9140(01)00369-1Pérez-Ruiz, T., Martínez-Lozano, C., Tomás, V., & Martín, J. (2002). FLOW INJECTION SPECTROFLUORIMETRIC DETERMINATION OF MALATHION IN ENVIRONMENTAL SAMPLES USING ON-LINE PHOTOOXIDATION. Analytical Letters, 35(7), 1239-1250. doi:10.1081/al-120005976Pérez-Ruiz, T., Martínez-Lozano, C., Tomás, V., & Martín, J. (2002). Fluorimetric determination of arsanilic acid by flow-injection analysis using on-line photo-oxidation. Analytical and Bioanalytical Chemistry, 372(2), 387-390. doi:10.1007/s00216-001-1173-yPérez-Ruiz, T., Martı́nez-Lozano, C., Tomás, V., & Martı́n, J. (2001). Flow-injection fluorimetric method for the determination of dimethylarsinic acid using on-line photo-oxidation. Analytica Chimica Acta, 447(1-2), 229-235. doi:10.1016/s0003-2670(01)01299-5Baird, C. 1995.Environmental Chemistry, 509–510. New York: W. H. Freeman and Company.Bauer, R., & Fallmann, H. (1997). The Photo-Fenton Oxidation — A cheap and efficient wastewater treatment method. Research on Chemical Intermediates, 23(4), 341-354. doi:10.1163/156856797x00565Huston, P. L., & Pignatello, J. J. (1999). Degradation of selected pesticide active ingredients and commercial formulations in water by the photo-assisted Fenton reaction. Water Research, 33(5), 1238-1246. doi:10.1016/s0043-1354(98)00330-3CATASTINI, C., SARAKHA, M., MAILHOT, G., & BOLTE, M. (2002). Iron (III) aquacomplexes as effective photocatalysts for the degradation of pesticides in homogeneous aqueous solutions. The Science of The Total Environment, 298(1-3), 219-228. doi:10.1016/s0048-9697(02)00219-xZepp, R. G., Schlotzhauer, P. F., & Sink, R. M. (1985). Photosensitized transformations involving electronic energy transfer in natural waters: role of humic substances. Environmental Science & Technology, 19(1), 74-81. doi:10.1021/es00131a008Pérez-Ruiz, T., Lozano, C. M., Tomás, V., & Martı́n, J. (2003). Flow injection chemiluminescence determination of carbaryl using photolytic decomposition and photogenerated tris (2,2′-bipyridyl)ruthenium(III). Analytica Chimica Acta, 476(1), 141-148. doi:10.1016/s0003-2670(02)01355-7Pérez-Ruiz, T., Martínez-Lozano, C., Tomás, V., & Martín, J. (2002). Chemiluminescence determination of carbofuran and promecarb by flow injection analysis using two photochemical reactions. The Analyst, 127(11), 1526-1530. doi:10.1039/b207460pMiles, C. J., & Moye, H. A. (1988). Postcolumn photolysis of pesticides for fluorometric determination by high-performance liquid chromatography. Analytical Chemistry, 60(3), 220-226. doi:10.1021/ac00154a007Soto-Chinchilla, J. J., Garcı́a-Campaña, A. M., Gámiz-Gracia, L., Cuadros-Rodrı́guez, L., & Vidal, J. L. M. (2004). Determination of a N-methylcarbamate pesticide in environmental samples based on the application of photodecomposition and peroxyoxalate chemiluminescent detection. Analytica Chimica Acta, 524(1-2), 235-240. doi:10.1016/j.aca.2004.05.084And, S. T., & Aaron, J. J. (1987). Fluorimetric Determination of Non-Fluorescent Dinitroaniline Derivative Herbicides, Using the Photoreduction of Anthraquinone - 2, 6-Disulfonate. Analytical Letters, 20(12), 1995-2009. doi:10.1080/00032718708078040Miles, C. J., & Anson Moye, H. (1987). High performance liquid chromatography with post-column photolysis of pesticides for generation of fluorophores. Chromatographia, 24(1), 628-632. doi:10.1007/bf02688556Patel, B. M., Moye, H. A., & Weinberger, R. (1990). Formation of fluorophores from nitrogenous pesticides by photolysis and reaction with OPA-2-mercaptoethanol for fluorescence detection in liquid chromatography. Journal of Agricultural and Food Chemistry, 38(1), 126-134. doi:10.1021/jf00091a027Durand, G., Barceló, D., Albaigés, J., & Mansour, M. (1990). Utilisation of liquid chromatography in aquatic photodegradation studies of pesticides: A comparison between distilled water and seawater. Chromatographia, 29(3-4), 120-124. doi:10.1007/bf02268696Rosen, J. D., Strusz, R. F., & Still, C. C. (1969). Photolysis of phenylurea herbicides. Journal of Agricultural and Food Chemistry, 17(2), 206-207. doi:10.1021/jf60162a046Lay, J. P., Klein, W., & Korte, F. (1975). Beiträge zur ökologischen Chemie C. Chemosphere, 4(3), 161-168. doi:10.1016/0045-6535(75)90094-6Tanaka, F. S., Hoffer, B. L., & Wien, R. G. (1985). Detection of halogenated biphenyls from sunlight photolysis of chlorinated herbicides in aqueous solution. Pesticide Science, 16(3), 265-270. doi:10.1002/ps.2780160309Pelizzetti, E., Maurino, V., Minero, C., Carlin, V., Tosato, M. L., Pramauro, E., & Zerbinati, O. (1990). Photocatalytic degradation of atrazine and other s-triazine herbicides. Environmental Science & Technology, 24(10), 1559-1565. doi:10.1021/es00080a016Chukwudebe, A., March, R. B., Othman, M., & Fukuto, T. R. (1989). Formation of trialkyl phosphorothioate esters from organophosphorus insecticides after exposure to either ultraviolet light or sunlight. Journal of Agricultural and Food Chemistry, 37(2), 539-545. doi:10.1021/jf00086a058Durand, G., De Bertrand, N., & Barceló, D. (1991). Applications of thermospray liquid chromatography-mass spectrometry in photochemical studies of pesticides in water. Journal of Chromatography A, 554(1-2), 233-250. doi:10.1016/s0021-9673(01)88453-3WOLFE, N., ZEPP, R., & PARIS, D. (1978). Carbaryl, propham and chlorpropham: A comparison of the rates of hydrolysis and photolysis with the rate of biolysis. Water Research, 12(8), 565-571. doi:10.1016/0043-1354(78)90134-3Samanidou, V., Fytianos, K., Pfister, G., & Bahadir, M. (1988). Photochemical decomposition of carbamate pesticides in natural waters of northern Greece. Science of The Total Environment, 76(1), 85-92. doi:10.1016/0048-9697(88)90287-2Konstantinou, I. K., Sakkas, V. A., & Albanis, T. A. (2001). Photocatalytic degradation of the herbicides propanil and molinate over aqueous TiO2 suspensions: identification of intermediates and the reaction pathway. Applied Catalysis B: Environmental, 34(3), 227-239. doi:10.1016/s0926-3373(01)00218-1Machado, F., Collin, L., & Boule, P. (1995). Photolysis of bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) in aqueous solution. Pesticide Science, 45(2), 107-110. doi:10.1002/ps.2780450203Boule, P., Guyon, C., & Lemaire, J. (1982). Photochemistry and environment IV- Photochemical behaviour of monochlorophenols in dilute aqueous solution. Chemosphere, 11(12), 1179-1188. doi:10.1016/0045-6535(82)90031-5Almansa Lopez, E. (2003). Simultaneous quantification of chlorophenoxyacid herbicides based on time-resolved photochemical derivatization to induce fluorescence in micellar medium. Talanta, 60(2-3), 355-367. doi:10.1016/s0039-9140(03)00109-7Garcia, L. F., Eremin, S., & Aaron, J.-J. (1996). Flow-Injection Analysis of Chlorophenoxyacid Herbicides using Photochemically Induced Fluorescence Detectiona. Analytical Letters, 29(8), 1447-1461. doi:10.1080/00032719608001493Lahuerta Zamora, L., Fuster Mestre, Y., Duart, M. J., Antón Fos, G. M., García Doménech, R., Gálvez Álvarez, J., & Martínez Calatayud, J. (2001). Prediction of the Chemiluminescent Behavior of Pharmaceuticals and Pesticides. Analytical Chemistry, 73(17), 4301-4306. doi:10.1021/ac010133iGómez-Taylor Corominas, B. (2003). Prediction of the chemiluminescent behaviour of phenols and polyphenols. Talanta, 60(2-3), 623-628. doi:10.1016/s0039-9140(03)00105-xPolo Martí, E., Catalá Icardo, M., Lahuerta Zamora, L., Antón Fos, G. M., & Martínez Calatayud, J. (2004). Theoretical prediction of the chemiluminescence behaviour of the ergot alkaloids. Analytica Chimica Acta, 527(2), 177-186. doi:10.1016/j.aca.2004.07.026P�rez-Ruiz, T., Mart�nez-Lozano, C., Tom�s, V., Sanz, A., & Garre, R. (2003). Flow Injection Spectrophotometric Determination of Ferbam Based on a Photochemical Reaction. Microchimica Acta, 142(4), 231-235. doi:10.1007/s00604-003-0027-zRoda, A., Rauch, P., Ferri, E., Girotti, S., Ghini, S., Carrea, G., & Bovara, R. (1994). Chemiluminescent flow sensor for the determination of Paraoxon and Aldicarb pesticides. Analytica Chimica Acta, 294(1), 35-42. doi:10.1016/0003-2670(94)85043-7Maniasso, N., Zagatto, E. A. G., Reis, S., Santos, J. L. M., & Lima, J. L. F. C. (1999). Exploitation of micellar medium for photochemical-spectrofluorimetric flow-injection determination of fenvalerate. Laboratory Automation & Information Management, 34(2), 143-148. doi:10.1016/s1381-141x(99)00016-7Vı́lchez, J. ., Valencia, M. ., Navalón, A., Molinero-Morales, B., & Capitán-Vallvey, L. . (2001). Flow injection analysis of the insecticide imidacloprid in water samples with photochemically induced fluorescence detection. Analytica Chimica Acta, 439(2), 299-305. doi:10.1016/s0003-2670(01)01039-

Stretched exponential relaxation for growing interfaces in quenched disordered media

We study the relaxation for growing interfaces in quenched disordered media. We use a directed percolation depinning model introduced by Tang and Leschhorn for 1+1-dimensions. We define the two-time autocorrelation function of the interface height C(t',t) and its Fourier transform. These functions depend on the difference of times t-t' for long enough times, this is the steady-state regime. We find a two-step relaxation decay in this regime. The long time tail can be fitted by a stretched exponential relaxation function. The relaxation time is proportional to the characteristic distance of the clusters of pinning cells in the direction parallel to the interface and it diverges as a power law. The two-step relaxation is lost at a given wave length of the Fourier transform, which is proportional to the characteristic distance of the clusters of pinning cells in the direction perpendicular to the interface. The stretched exponential relaxation is caused by the existence of clusters of pinning cells and it is a direct consequence of the quenched noise.Comment: 4 pages and 5 figures. Submitted (5/2002) to Phys. Rev.

Hereditary gingival fibromatosis : characteristics and treatment approach

Hereditary gingival fibromatosis (HGF) is a rare disorder characterized by a benign, non-hemorrhagic, fibrous gingival overgrowth that can appear in isolation or as part of a syndrome. Clinically, a pink gingiva with marked stippling can be seen to cover almost all the tooth, in many cases preventing eruption. HGF usually begins during the transition from primary to permanent teeth, giving rise to a condition that can have negative psychological effects at that age. As it does not resolve spontaneously, the treatment of choice is gingivectomy, which can be performed with an internal or external bevel incision, depending on each case and bearing in mind the changes that will take place at the dentogingival junction (DGJ). This paper describes clinical aspects and treatment in two eight-year-old boys with HGF, considering different facets of the surgical approach with conscious sedation in young children

Development of a photoinduced chemiluminescent method for the determination of the herbicide quinmerac in water

This paper was published in APPLIED SPECTROSCOPY and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1366/14-07791 . Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.A new, simple and sensitive method, based on photoinduced chemiluminescence, was developed for the determination of quinmerac. The photoproduct, obtained after UV irradiation in basic medium, was mixed with sodium sulfite (sensitizer), and Ce(IV) (oxidant) in acid medium. A wide linear dynamic range (2-600 ng mL-1) and a limit of detection of 0.6 ng mL-1 were obtained without any pretreatment (0.08 ng mL-1 after solid phase extraction). The determination was performed using a flow injection manifold, which allowed a high throughput (144 h-1). The inter-day reproducibility was 5.6% (n=5), and the intra-day repeatability was 3.9 and 2.9% for 20 and 200 ng mL-1 of quinmerac, respectively (n=21). Finally, the method was applied to surface and ground waters with recoveries ranging from 78.1 to 94.5%.The authors thank the Ministerio de Educacion y Ciencia from Spain and FEDER for financial support, Project CTM2006-11991.Catalá-Icardo, M.; López Paz, JL.; Blázquez Pérez, J. (2015). Development of a photoinduced chemiluminescent method for the determination of the herbicide quinmerac in water. Applied Spectroscopy. 69(10):1199-1204. https://doi.org/10.1366/14-07791S119912046910Rodríguez, V. A., Mazza, S. M., Martínez, G. C., Alvarenga, L., Píccoli, A. B., Ortiz, M. L., & Avanza, M. M. (2007). Uso de reguladores de crescimento para incrementar la productividad de mandarino «clemenules». Revista Brasileira de Fruticultura, 29(1), 48-56. doi:10.1590/s0100-29452007000100012Vieira, C. R. Y. I., Pires, E. J. P., Terra, M. M., Tecchio, M. A., & Vieira, M. do C. (2008). Reguladores vegetais influenciando número e tamanho de células das bagas da uva «Niagara Rosada». Revista Brasileira de Fruticultura, 30(1), 25-30. doi:10.1590/s0100-29452008000100007Deschauer, H., & Kögel-Knabner, I. (1990). Sorption behavior of a new acidic herbicide in soils. Chemosphere, 21(12), 1397-1410. doi:10.1016/0045-6535(90)90044-tSalinas-Castillo, A., Fernández-Sanchez, J. F., Segura-Carretero, A., & Fernández-Gutiérrez, A. (2005). Simple determination of the herbicide napropamide in water and soil samples by room temperature phosphorescence. Pest Management Science, 61(8), 816-820. doi:10.1002/ps.1054Dagnac, T., Garcia-Chao, M., Pulleiro, P., Garcia-Jares, C., & Llompart, M. (2009). Dispersive solid-phase extraction followed by liquid chromatography–tandem mass spectrometry for the multi-residue analysis of pesticides in raw bovine milk. Journal of Chromatography A, 1216(18), 3702-3709. doi:10.1016/j.chroma.2009.02.048ALDER, L., LUDERITZ, S., LINDTNER, K., & STAN, H. (2004). The ECHO technique – the more effective way of data evaluation in liquid chromatography–tandem mass spectrometry analysis. Journal of Chromatography A, 1058(1-2), 67-79. doi:10.1016/s0021-9673(04)01479-7Lacina, O., Urbanova, J., Poustka, J., & Hajslova, J. (2010). Identification/quantification of multiple pesticide residues in food plants by ultra-high-performance liquid chromatography-time-of-flight mass spectrometry. Journal of Chromatography A, 1217(5), 648-659. doi:10.1016/j.chroma.2009.11.098Lacina, O., Zachariasova, M., Urbanova, J., Vaclavikova, M., Cajka, T., & Hajslova, J. (2012). Critical assessment of extraction methods for the simultaneous determination of pesticide residues and mycotoxins in fruits, cereals, spices and oil seeds employing ultra-high performance liquid chromatography–tandem mass spectrometry. Journal of Chromatography A, 1262, 8-18. doi:10.1016/j.chroma.2012.08.097Greulich, K., & Alder, L. (2008). Fast multiresidue screening of 300 pesticides in water for human consumption by LC-MS/MS. Analytical and Bioanalytical Chemistry, 391(1), 183-197. doi:10.1007/s00216-008-1935-xWode, F., Reilich, C., van Baar, P., Dünnbier, U., Jekel, M., & Reemtsma, T. (2012). Multiresidue analytical method for the simultaneous determination of 72 micropollutants in aqueous samples with ultra high performance liquid chromatography–high resolution mass spectrometry. Journal of Chromatography A, 1270, 118-126. doi:10.1016/j.chroma.2012.10.054Romero-González, R., Frenich, A. G., & Vidal, J. L. M. (2008). Multiresidue method for fast determination of pesticides in fruit juices by ultra performance liquid chromatography coupled to tandem mass spectrometry. Talanta, 76(1), 211-225. doi:10.1016/j.talanta.2008.02.041Mantzos, N., Karakitsou, A., Zioris, I., Leneti, E., & Konstantinou, I. (2013). QuEChERS and solid phase extraction methods for the determination of energy crop pesticides in soil, plant and runoff water matrices. International Journal of Environmental Analytical Chemistry, 93(15), 1566-1584. doi:10.1080/03067319.2013.803282Vandecasteele, K., Gaus, I., Debreuck, W., & Walraevens, K. (2000). Identification and Quantification of 77 Pesticides in Groundwater Using Solid Phase Coupled to Liquid−Liquid Microextraction and Reversed-Phase Liquid Chromatography. Analytical Chemistry, 72(14), 3093-3101. doi:10.1021/ac991359cIcardo, M. (2003). FI-on line photochemical reaction for direct chemiluminescence determination of photodegradated chloramphenicol. Talanta, 60(2-3), 405-414. doi:10.1016/s0039-9140(03)00074-2Sun, S., & Lu, J. (2006). Flow-injection post chemiluminescence determination of atropine sulfate. Analytica Chimica Acta, 580(1), 9-13. doi:10.1016/j.aca.2006.07.049Pinna, M. V., & Pusino, A. (2012). Direct and indirect photolysis of two quinolinecarboxylic herbicides in aqueous systems. Chemosphere, 86(6), 655-658. doi:10.1016/j.chemosphere.2011.11.016Yu, X., Jiang, Z., Wang, Q., & Guo, Y. (2010). Silver nanoparticle-based chemiluminescence enhancement for the determination of norfloxacin. Microchimica Acta, 171(1-2), 17-22. doi:10.1007/s00604-010-0401-6Zhang, J., Li, J., & Tu, Y. (2009). Flow injection determination of benzhexol based on its sensitizing effect on the chemiluminescent reaction of Ce(IV)-sulfite. Luminescence, 25(4), 317-321. doi:10.1002/bio.1154AL-ARFAJ, N. A., AL-ABDULKAREEM, E. A., & ALY, F. A. (2009). Flow-Injection Chemiluminometric Determination of Pioglitazone HCl by Its Sensitizing Effect on the Cerium-Sulfite Reaction. Analytical Sciences, 25(3), 401-406. doi:10.2116/analsci.25.401Liu, H., Ren, J., Hao, Y., Ding, H., He, P., & Fang, Y. (2006). Determination of metoprolol tartrate in tablets and human urine using flow-injection chemiluminescence method. Journal of Pharmaceutical and Biomedical Analysis, 42(3), 384-388. doi:10.1016/j.jpba.2006.04.008SUN, H., LI, L., & CHEN, X. (2006). Flow-Injection Chemiluminescence Determination of Ofloxacin and Levofloxacin in Pharmaceutical Preparations and Biological Fluids. Analytical Sciences, 22(8), 1145-1149. doi:10.2116/analsci.22.1145Aly, F. (2001). Flow-injection chemiluminometric analysis of some benzamides by their sensitizing effect on the cerium-sulphite reaction. Talanta, 54(4), 715-725. doi:10.1016/s0039-9140(01)00320-4Sun, C., Lian, N., Zhao, H., Yi, L., & Jin, L. (2004). Flow Injection Determination of Lomefloxacin Based on Photochemically Sensitized Chemiluminescence. Microchimica Acta, 148(1-2). doi:10.1007/s00604-004-0253-zNie, L.-H., Zhao, H.-C., Wang, X., Yi, L., Lu, Y., Jin, L.-P., & Ma, H.-M. (2002). Determination of lomefloxacin by terbium sensitized chemiluminescence method. Analytical and Bioanalytical Chemistry, 374(7-8), 1187-1190. doi:10.1007/s00216-002-1553-yMeseguer-Lloret, S., Torres-Cartas, S., & Gómez-Benito, M. C. (2010). Flow injection photoinduced chemiluminescence determination of imazalil in water samples. Analytical and Bioanalytical Chemistry, 398(7-8), 3175-3182. doi:10.1007/s00216-010-4227-1Catalá-Icardo, M., López-Paz, J. L., Choves-Barón, C., & Peña-Bádena, A. (2012). Native vs photoinduced chemiluminescence in dimethoate determination. Analytica Chimica Acta, 710, 81-87. doi:10.1016/j.aca.2011.10.043Torres-Cartas, S., Gómez-Benito, C., & Meseguer-Lloret, S. (2011). FI on-line chemiluminescence reaction for determination of MCPA in water samples. Analytical and Bioanalytical Chemistry, 402(3), 1289-1296. doi:10.1007/s00216-011-5567-1Gómez-Benito, C., Meseguer-Lloret, S., & Torres-Cartas, S. (2013). Sensitive determination of Fenamiphos in water samples by flow injection photoinduced chemiluminescence. International Journal of Environmental Analytical Chemistry, 93(2), 152-165. doi:10.1080/03067319.2012.663755Hamilton, D. J., Ambrus, Á., Dieterle, R. M., Felsot, A. S., Harris, C. A., Holland, P. T., … Wong, S.-S. (2003). Regulatory limits for pesticide residues in water (IUPAC Technical Report). Pure and Applied Chemistry, 75(8), 1123-1155. doi:10.1351/pac20037508112

Integration of occupational risk prevention courses in engineering degrees: Delphi study

Engineering syllabi often lack courses covering occupational risk prevention. In Spain, professional competences are awarded along with the completion of a university degree. This means that new graduates are certified in areas in which they have received little or no training, such as occupational risk prevention. However, the academic reforms established by the Bologna Process, which strives to homogenize university degrees throughout Europe, compels European universities to design new syllabi. The main goal of this paper is to define a framework for including occupational risk-prevention education in the new engineering syllabi. This exploratory research applied the Delphi methodology to a panel of 59 experts, using questionnaires assessed with a four-point Likert scale through two rounds. A website supported the information flow. According to the experts who participated in this study, education and training in occupational risk-prevention is essential for improving the safety culture within a company or workplace. The experts concurred that this subject should be a separate mandatory course in all engineering degree programs. The participants recommended that an optional course should be considered only if a mandatory course is not approved. It was also deemed desirable to integrate occupational risk prevention as a cross-field subject in other technological courses, even if the curriculum already includes some related courses. © 2012 American Society of Civil Engineers.Cortés Díaz, JM.; Pellicer Armiñana, E.; Catalá Alís, J. (2012). Integration of occupational risk prevention courses in engineering degrees: Delphi study. Journal of Professional Issues in Engineering Education and Practice. 138(1):31-36. doi:10.1061/(ASCE)EI.1943-5541.0000076S3136138

Dissolved Organic Matter (DOM) in the open Mediterranean Sea. I. Basin-Wide distribution and drivers of chromophoric DOM

Original research articleChromophoric dissolved organic matter (CDOM) in the open Mediterranean Sea (MedSea) is barely documented, remaining the basin–wide patterns in intermediate and deep waters still enigmatic. Here, full–depth distributions of CDOM absorption coefficients and spectral slopes recorded during the HOTMIX 2014 cruise are presented and their respective environmental drivers resolved. General Additive Models (GAMs) in surface waters and Optimum MultiParameter (OMP) water mass analysis in deep waters were applied. In the surface, apparent oxygen utilisation (AOU), a proxy to cumulative net community respiration, explained most of the variability of dissolved organic carbon (DOC) and the absorption coefficient at 254 nm (a254), whereas the absorption coefficient at 325 nm (a325), and the spectral slopes were mostly explained by potential temperature, a proxy to stratification and solar radiation, indicating that both water column stability and photobleaching may drive the variability of the UV–A absorbing CDOM components. In deep waters, the effect of water mass mixing and basin–scale mineralization were discerned from local mineralization processes. Water mass mixing and basin–scale mineralization contributed more substantially to explain the variability of DOC, a254 and a325 (82–91%) than the variability of the spectral slopes (35–64%). Local mineralization processes indicate that DOC and CDOM play a more relevant role in the carbon cycle in the Eastern (EastMed) than in the Western (WestMed) Mediterranean: whereas DOC contributed to 66 ± 10% of the oxygen demand in the EastMed, it represented only 24 ± 4% in the WestMed. Independently of basins and layers, a254 revealed as an excellent proxy to the concentration of DOC in the MedSea. Also, the unexpected inverse relationship of a325 with AOU indicates that the consumption of the UV–A absorbing CDOM fraction prevails over their productionSpanish Ministry of Education and Culture, Spanish Ministry of Economy and Competitiviness, FEDER, CSIC, University of GranadaVersión del editor3,26

Epigenetics and periodontics : a systematic review

Despite decades of research, our knowledge of several important aspects of periodontal pathogenesis remains incomplete. Epigenetics allows to perform dynamic analysis of different variations in gene expression, providing this great advantage to the static measurement provided by genetic markers. The aim of this systematic review is to analyze the possible relationships between different epigenetic mechanisms and periodontal diseases, and to assess their potential use as biomarkers of periodontitis. A systematic search was conducted in six databases using MeSH and non-MeSH terms. The review fulfilled PRISMA criteria (Preferred Reporting Items for Systematic reviews and Meta-analysis). 36 studies met the inclusion criteria. Due to the heterogeneity of the articles, it was not possible to conduct quantitative analysis. Regarding qualitative synthesis, however, it was found that epigenetic mechanisms may be used as biological markers of periodontal disease, as their dynamism and molecular stability makes them a valuable diagnostic tool. Epigenetic markers alter gene expression, producing either silencing or over-expression of molecular transcription that respond to the demands of the cellular surroundings. Gingival crevicular fluid collection is a non-invasive and simple procedure, which makes it an ideal diagnostic medium for detection of both oral and systemic issues. Although further research is needed, this seems to be a promising field of research in the years to come

A Bridging bis-Allyl Titanium Complex: Mechanistic Insights into the Electronic Structure and Reactivity

Treatment of the dinuclear compound [{Ti(η5-C5Me5)Cl2}2(μ-O)] with allylmagnesium chloride provides the formation of the allyltitanium(III) derivative [{Ti(η5-C5Me5)(μ-C3H5)}2(μ-O)] (1), structurally identified by single-crystal X-ray analysis. Density functional theory (DFT) calculations confirm that the electronic structure of 1 is a singlet state, and the molecular orbital analysis, along with the short Ti −Ti distance, reveal the presence of a metal −metal single bond between the two Ti(III) centers. Complex 1 reacts rapidly with organic azides, RN3 (R = Ph, SiMe3), to yield the allyl μ-imido derivatives [{Ti(η5-C5Me5)(CH2CH=CH2)}2(μ-NR)(μ-O)] [R = Ph(2), SiMe3(3)] along with molecular nitrogen release. Reaction of 2 and 3 with H2 leads to the μ-imido propyl species [{Ti(η5-C5Me5)(CH2CH2CH3)}2(μ-NR)(μ-O)] [R = Ph(4), SiMe3(5)]. Theoretical calculations were used to gain insight into the hydrogenation mechanism of complex 3 and rationalize the lower reactivity of 2. Initially, the μ-imido bridging group in these complexes activates the H2 molecule via addition to the Ti −N bonds. Subsequently, the titanium hydride intermediates induce a change in hapticity of the allyl ligands, and the nucleophilic attack of the hydride to the allyl groups leads to metallacyclopropane intermediates. Finally, the proton transfer from the amido group to the metallacyclopropane moieties affords the propyl complexes 4 and 5.Ministerio de Ciencia, Innovación y Universidades Universidad de Alcalá Generalitat de Cataluny