Effects Of Thermocycling And Light Source On The Bond Strength Of Metallic Brackets To Bovine Teeth

This study evaluated the effects of thermocycling and different light sources on the bond strength of metallic brackets to bovine tooth enamel using an adhesive resin. Bovine teeth were etched with 35% phosphoric acid gel for 20 s. After application of primer, metallic brackets were bonded to the buccal surface using Transbond XT, forming 8 groups (n=20), depending on the light source used for photoactivation (AccuCure 3000 argon laser - 20 s, Apollo 95E plasma arc - 12 s, UltraLume 5 LED - 40 s and XL2500 halogen light - 40 s) and experimental conditions without (Groups 1 to 4) or with thermocycling (Groups 5 to 8). Shear bond testing was carried out after 24 h of distilled water storage (Groups 1 to 4) or storage and thermocycling in distilled water (groups 5 to 8; 1,500 cycles - 5°/55°C). Data were subjected to two-way ANOVA and Tukey's test (α=0.05). The Adhesive Remnant Index (ARI) was evaluated at ×8 magnification. No significant differences (p>0.05) in bond strength were found when the conditions without and with thermocycling were compared for any of the light sources. No significant differences (p>0.05) in bond strength were found among the light sources, irrespective of performing or not thermocycling. There was a predominance of ARI scores 1 in all groups. In conclusion, light sources and thermocycling had no influence on the bond strength of brackets to bovine enamel.226486489Sfondrini, M.F., Cacciafesta, V., Scribante, A., Klersy, C., Plasma arc versus halogen light curing of orthodontic brackets: A 12-month clinical study of bond failures (2004) Am J Orthod Dentofacial Orthop, 125, pp. 342-347Dall'igna, C.M., Marchioro, E.M., Spohr, A.M., Mota, E.G., Effect of curing time on the bond strength of a bracket-bonding system cured with a light-emitting diode or plasma arc light (2011) Eur J Orthod, 33, pp. 55-59Correr, A.B., Sinhoreti, M.A., Sobrinho, L.C., Tango, R.N., Schneider, L.F., Consani, S., Effect of the increase of energy density on Knoop hardness of dental composites light-cured by conventional QTH, LED and xenon plasma arc (2005) Braz Dent J, 16, pp. 218-224Cekic-Nagas, I., Egilmez, F., Ergun, G., The effect of irradiation distance on microhardness of resin composites cured with different light curing units (2010) Eur J Dent, 4, pp. 440-446Thind, B.S., Stirrups, D.R., Lloyd, C.H., A comparison of tungsten- quartz halogen, plasma arc and light-emitting diode light sources for the polymerization of an orthodontic adhesive (2006) Eur J Orthod, 28, pp. 78-82Filipov, I.A., Vladimirov, S.B., Residual monomer in a composite resin after light-curing with different sources, light intensities and spectra of radiation (2006) Braz Dent J, 17, pp. 34-38Park, J.K., Hur, B., Ko, C.C., García-Godoy, F., Kim, H.I., Kwon, Y.H., Effect of light-curing units on the thermal expansion of resin nanocomposites (2010) Am J Dent, 23, pp. 331-334Price, R.B., Labrie, D., Rueggeberg, F.A., Felix, C.M., Irradiance differences in the violet (405 nm) and blue (460 nm) spectral ranges among dental light-curing units (2010) J Esthet Restor Dent, 22, pp. 363-377Gonçalves, P.R.A., Moraes, R.R., Costa, A.R., Correr, A.B., Nouer, P.R.A., Sinhoreti, M.A.C., Effect of etching time and light source on the bond strength of metallic brackets to ceramic (2011) Braz Dent J, 22, pp. 245-248Swanson, T., Dunn, W.J., Childers, D.E., Taloumis, L.J., Shear bond strength of orthodontic brackets bonded with light-emitting diode curing units at various polymerization times (2004) Am J Orthod Dentofacial Orthop, 125, pp. 337-341Usumez, S., Buyukyilmaz, T., Karaman, A.I., Effect of light-emitting diode on bond strength of orthodontic brackets (2004) Angle Orthod, 74, pp. 259-263Talbot, T.Q., Blankenau, R.J., Zobitz, M.E., Weaver, A.L., Lohse, C.M., Rebellato, J., Effect of argon laser irradiation on shear bond strength of orthodontic brackets: An in vitro study (2000) Am J Orthod Dentofacial Orthop, 118, pp. 274-279Klocke, A., Korbmacher, H.M., Huck, L.G., Kahl-Nieke, B., Plasma arc curing lights for orthodontic bonding (2002) Am J Orthod Dentofacial Orthop, 122, pp. 643-648Bishara, S.E., Ostby, A.W., Laffoon, J.F., Warren, J., Shear bond strength comparison of two adhesive systems following thermocycling (2007) Angle Orthod, 77, pp. 337-341Faltermeier, A., Müssig, D., A comparative evaluation of bracket bonding with 1-, 2-, and 3-component adhesive systems (2007) Am J Orthod Dentofacial Orthop, 132, pp. 144.e1-144.e5Gale, M.S., Darvell, B.W., Thermal cycling procedures for laboratory testing of dental restorations (1999) J Dent, 27, pp. 89-99Trites, B., Foley, T.F., Banting, D., Bond strength comparison of 2 self-etching primers over a 3-month storage period (2004) Am J Orthod Dentofacial Orthop, 126, pp. 709-716Yuasa, T., Iijima, M., Ito, S., Muguruma, T., Saito, T., Mizoguchi, I., Effects of long-term storage and thermocycling on bond strength of two self-etching primer adhesive systems (2010) Eur J Orthod, 32, pp. 285-290Artun, J., Berglund, S., Clinical trials with crystal growth conditioning as an alternative to acid-etch enamel pretreatment (1984) Am J Orthod, 85, pp. 333-340Oesterle, L.J., Newman, S.M., Shellhart, W.C., Rapid curing of bondingcomposite with a xenon plasma arc light (2001) Am J Orthod Dentofacial Orthop, 119, pp. 610-616Staudt, C.B., Mavropoulos, A., Bouil, L.S., Kiliaridis, S., Krejcid, I., Light-curing time reduction with a new high-power halogen lamp (2005) Am J Orthod Dentofacial Orthop, 128, pp. 749-754Yu, H.S., Lee, K.J., Jin, G.C., Baik, H.S., Comparison of the shear bond strength of brackets using the LED curing light and plasma arc curing light: Polymerization time (2007) World J Orthod, 8, pp. 129-135Rueggeberg, F., Contemporary issues in photocuring (1999) Compend Contin Educ Dent Suppl, pp. 4-15de Munck, J., van Landuyt, K., Peumans, M., Poitevin, A., Lambrechts, P., Braem, M., A critical review of the durability of adhesion of tooth tissue: Methods and results (2005) J Dent Res, 84, pp. 118-132Reynolds, I.R., Composite filling materials as adhesives in Orthodontics (1975) Br Dent J, 138, p. 8

Human dimensions of climate change: the vulnerability of small farmers in the Amazon

This paper argues for a twofold perspective on human adaptation to climate change in the Amazon. First, we need to understand the processes that mediate perceptions of environmental change and the behavioural responses at the levels of the individual and the local population. Second, we should take into account the process of production and dissemination of global and national climate information and models to regional and local populations, especially small farmers. We discuss the sociocultural and environmental diversity of small farmers in the Amazon and their susceptibility to climate change associated with drought, flooding and accidental fire. Using survey, ethnographic and archival data from study areas in the state of Pará, we discuss farmers' sources of knowledge and long-term memory of climatic events, drought and accidental fire; their sources of climate information; their responses to drought and fire events and the impact of changing rainfall patterns on land use. We highlight the challenges of adaptation to climate change created by the influence of migration and family turnover on collective action and memory, the mismatch of scales used to monitor and disseminate climate data and the lack of extension services to translate large-scale forecasts to local needs. We found that for most farmers, memories of extended drought tend to decrease significantly after 3 years. Over 50% of the farmers interviewed in 2002 did not remember as significant the El Niño Southern Oscillation (ENSO) drought of 1997/1998. This helps explain why approximately 40% of the farmers have not changed their land-use behaviours in the face of the strongest ENSO event of the twentieth century

Theoretical description of phase coexistence in model C60

We have investigated the phase diagram of the Girifalco model of C60 fullerene in the framework provided by the MHNC and the SCOZA liquid state theories, and by a Perturbation Theory (PT), for the free energy of the solid phase. We present an extended assessment of such theories as set against a recent Monte Carlo study of the same model [D. Costa et al, J. Chem. Phys. 118:304 (2003)]. We have compared the theoretical predictions with the corresponding simulation results for several thermodynamic properties. Then we have determined the phase diagram of the model, by using either the SCOZA, or the MHNC, or the PT predictions for one of the coexisting phases, and the simulation data for the other phase, in order to separately ascertain the accuracy of each theory. It turns out that the overall appearance of the phase portrait is reproduced fairly well by all theories, with remarkable accuracy as for the melting line and the solid-vapor equilibrium. The MHNC and SCOZA results for the liquid-vapor coexistence, as well as for the corresponding critical points, are quite accurate. All results are discussed in terms of the basic assumptions underlying each theory. We have selected the MHNC for the fluid and the first-order PT for the solid phase, as the most accurate tools to investigate the phase behavior of the model in terms of purely theoretical approaches. The overall results appear as a robust benchmark for further theoretical investigations on higher order C(n>60) fullerenes, as well as on other fullerene-related materials, whose description can be based on a modelization similar to that adopted in this work.Comment: RevTeX4, 15 pages, 7 figures; submitted to Phys. Rev.

Efectos geológicos asociados al sismo de 7,9 Mw en Pisco - Perú

Se efectuaron estudios en las zonas afectadas por el sismo, con el fin de evaluar los procesos geológicos. Se reconocieron deformaciones superficiales en las zonas costeras, movimientos en masa en los taludes de corte de carretera y reacomodo en algunos antiguos depósitos de deslizamientos. En la interpretación de los principales procesos geológicos asociados al sismo. De acuerdo a las características de los daños se pueden señalar los siguientes. La licuación o licuefacción de suelos en áreas aluviales, con nivel freático superficial, incluye sedimentos de la Formación Pisco; los efectos de Tsunamis a lo largo de la Costa, incidiendo sobre infraestructura civil; los fracturamientos, fallas y deslizamientos en cuñas, colapsos y derrumbes; los movimientos en masa en acantilados costeros, en taludes de carreteras, en laderas naturales; las caídas de detritos en los sedimentos pliocuaternarios de las Formaciones Cañete y Topará en depósitos eólicos; la reactivación de antiguos depósitos de movimientos en masa antiguos. Los procesos geológicos co-sísmicos responsables de los daños principales tuvieron lugar en un radio de acción de 200 km² del epicentro

Procesos geológicos e intensidad macrosísmica INQUA del sismo de Pisco del 15/08/2007, Perú

[ES] --- El 15 de agosto de 2007 las ciudades de Pisco, Ica, Chincha y Cañete, ubicadas entre 140 y 300 km al sur de la capital peruana, fueron afectadas por un sismo de magnitud 7,9 (Mw). Los reportes finales del Instituto Nacional de Defensa Civil indicaron la ocurrencia de 519 muertes y entre 655 y 679 viviendas afectadas. Fueron severamente dañadas ciudades como Pisco, San Clemente y Tambo de Mora, áreas agrícolas en los valles de Pisco y Cañete y varios tramos de la carretera panamericana sur. Lugares turísticos en la Reserva Nacional de Paracas fueron destruidos, vías de penetración a la sierra de Ica, Huancavelica y Lima fueron bloqueadas, y poblaciones asentadas sobre depósitos de antiguos deslizamientos sufrieron daños (Laraos, Chocos, Huangascar, Tantará). Balnearios, caletas y muelles artesanales en la zona litoral, áreas agrícolas y algunas granjas avícolas sufrieron los efectos de un tsunami. Procesos geológicos cosísmicos y postsísmicos responsables de los daños, ocurrieron en un radio de 200 km del epicentro. Deformaciones superficiales asociadas a licuación y expansión lateral se presentaron en las planicies y valles aluviales costeros, afectando sedimentitas terciarias y depósitos recientes, con niveles freáticos superficiales. Movimientos en masa (caída de rocas, derrumbes y deslizamientos), ocurrieron entre 32 y 198 km del epicentro, con volúmenes acumulados de 14.750 m3 (costa) y 9.585 m3 (sierra). Olas de tsunami post-sismo, alcanzaron un run up de hasta 10 m (playa Yumaque) y hasta 2 km de inundación (playa Lagunillas), en la Reserva Nacional de Paracas. La descripción geológica y geomorfológica de estos procesos, indicaron que el sismo de Pisco alcanzó un grado entre VII y VIII utilizando la escala de intensidad macrosísmica INQUA.[EN] --- In August 15th, 2007 the cities of Pisco, Ica, Chincha and Cañete, located south of the Peruvian capital city, were affected for a mayor earthquake (7.9 Mw). The final report from the National Institute of Civil Defense totaled 519 casualties and 655 to 679 damaged houses. Cities like Pisco, San Clemente and Tambo de Mora were severely affected, as well as agricultural areas in Pisco and Cañete valleys. The Panamericana highway was considerablely affected. In the National Reserve Paracas many tourist places were destroyed and many secondary roads that connect the coastal area with the high part of the Andes (Ica, Huancavelica and Lima) were blocked due to rock falls. Small towns in the Andes placed on ancient landslide deposits were damaged (Laraos, Chocos, Huangascar, Tantará). Seaside resorts, creeks and small docks in the coastal area and some chicken farms were affected by the tsunami. Coseismic and postseismic geological processes were responsible for the damage in a 200 km radius from the epicenter. Ground deformation and lateral spreading happened in Tertiary sediments due to a shallow of the ground water table. Mass movements (rock fall, collapsing and landslides) are located between 32 and 198 km from the epicenter, with accumulated volumes of 14,750 m3(Coastal area) and 9, 585 m3 (Andes area). The tsunami waves got 10 m of run up (Yumaque beach) and up to 2 km of flooding at the beach zone (Lagunillas beach) in the National Reserve of Paracas. The geological and geomorphological descriptions of this process determine that that the Pisco earthquake reached a VII and VIII grade on the INQUA macro-seismic intensity scale

Peptides from the variable region of specific antibodies are shared among lung cancer patients

Late diagnosis of lung cancer is still the main reason for high mortality rates in lung cancer. Lung cancer is a heterogeneous disease which induces an immune response to different tumor antigens. Several methods for searching autoantibodies have been described that are based on known purified antigen panels. The aim of our study is to find evidence that parts of the antigen-binding-domain of antibodies are shared among lung cancer patients. This was investigated by a novel approach based on sequencing antigen-binding- fragments (Fab) of immunoglobulins using proteomic techniques without the need of previously known antigen panels. From serum of 93 participants of the NELSON trial IgG was isolated and subsequently digested into Fab and Fc. Fab was purified from the digested mixture by SDS-PAGE. The Fab containing gel-bands were excised, tryptic digested and measured on a nano-LC-Orbitrap-Mass- spectrometry system. Multivariate analysis of the mass spectrometry data by linear canonical discriminant analysis combined with stepwise logistic regression resulted in a 12-antibody-peptide model which was able to distinguish lung cancer patients from controls in a high risk population with a sensitivity of 84% and specificity of 90%. With our Fab-purification combined Orbitrap-mass-spectrometry approach, we found peptides from the variable-parts of antibodies which are shared among lung cancer patients

Kaluza-Klein Cosmology With Modified Holographic Dark Energy

We investigate the compact Kaluza-Klein cosmology in which modified holographic dark energy is interacting with dark matter. Using this scenario, we evaluate equation of state parameter as well as equation of evolution of the modified holographic dark energy. Further, it is shown that the generalized second law of thermodynamics holds without any constraint.Comment: 13 pages, accepted for publication in Gen. Relativ. Gravi

Cultural Orientations of sport managers

Various interpretations of sport management are cultural constructs underpinned by core assumptions and values held by members of professional communities. Sport managers world wide share common problems, but differ in how they resolve them. These universal differences emerge from the relationships they form with other people, and their attitude to time, activities and the natural environment. This paper examines the role of sport managers’ cultural orientations in the interpretation and practice of sport management. Using a multiple dimension model (Hampden-Turner and Trompenaars, 2000) it sketches the cultural profiles of fifteen sport managers from seven countries. A combination of methods was employed including questionnaires, interviews and participant observation. It is contended that the culture of sport management concerns a social process by which managers get involved in reconciling seven fundamental cultural dilemmas in order to perform tasks and achieve certain ends. Thus, a knowledge of the cultural meaning of sport management in a particular country would equip sport managers with a valuable tool in managing both the cultural diversity of their own work forces and in developing appropriate cross-cultural skills needed for running international events, marketing campaigns, sponsorship deals and joint ventures

Hazardous faults of South America; compilation and overview

The heterogeneous South American geology has coined a wide variety of neotectonic settings where crustal seismogenic sources do occur. This fact has led to different approaches for mapping and inventory neotectonic structures. The South American Risk Assessment project promoted the discussion and update under uniform standards of the available information on neotectonic deformation, for its application in regional Probabilistic Seismic Hazard Assessments. As a result, 1533 hazardous faults have been inventoried onshore South America, 497 of them qualifying to feed the engine model driving probabilistic maps. Main hazardous structures are concentrated throughout the eastern boundary of the Northern Andean Sliver and along the foreland-facing Andean Thrust Front. Space geodesy and seismicity illuminate the seismogenic significance of these deformation belts, although few neotectonic surveys have been conducted to date in the latter region. The characteristics of the main structures or deformation zones are here outlined according to their filiation to neotectonic domains, which are dependant on the geologic, seismotectonic, or morphotectonic settings in Andean and extra-Andean regions. The knowledge accrued on the hazardous faults in South America here compiled, reinforces the fact that some of these structures constitute significant hazard sources for many urban areas and critical facilities and should be incorporated in seismic hazard assessments. However, the available fault data are insufficient in many cases or carry significant epistemic uncertainties for fault source characterization. This contribution aims to summarize the present knowledge on the South American hazardous faults as well as the main challenges for successful fault data incorporation into seismic hazard models