(2014) Safety and efficacy of aerobic training in operable breast cancer patients receiving neoadjuvant chemotherapy: A phase II randomized trial, Acta Oncologica, 53:1, 65-74,
[1] Oceanic emissions of gaseous organic iodine-atom precursors have the potential to significantly affect atmospheric chemistry and climate, however there is currently considerable uncertainty associated with quantifying their sources. We present sea-air fluxes calculated from simultaneous air and seawater measurements of a comprehensive range of volatile organic iodine compounds (VOICs), including CH 3 I and the less commonly reported dihalomethanes CH 2 ICl, CH 2 IBr and CH 2 I 2 , made during two cruises in the Atlantic Ocean between 15-58°N. The combined dihalomethane flux provides a global iodine source (∼0.33 ± 0.19 Tg I y −1 ) comparable to that of CH 3 I, and a surface iodine atom source 3-4 times higher. However, a 1D atmospheric model reveals that, in the tropical east Atlantic Ocean in the vicinity of Cape Verde, even these combined VOIC fluxes are capable of supporting only ∼10-25% of the observed IO levels, and suggests that a substantial (340-640 nmol I m −2 d −1 ) additional photochemical source of iodine is required.
Abstract. Air-sea fluxes and bulk seawater and atmospheric concentrations of bromoform (CHBr 3 ) and dibromomethane (CH 2 Br 2 ) were measured during two research cruises in the northeast Atlantic (53-59 • N, June-July 2006) and tropical eastern Atlantic Ocean including over the African coastal upwelling system (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) • N May-June 2007). Saturations and sea-air fluxes of these compounds generally decreased in the order coastal > upwelling > shelf > open ocean, and outside of coastal regions, a broad trend of elevated surface seawater concentrations with high chlorophyll-a was observed. We show that upwelling regions (coastal and equatorial) represent regional hot spots of bromocarbons, but are probably not of major significance globally, contributing at most a few percent of the total global emissions of CHBr 3 and CH 2 Br 2 . From limited data from eastern Atlantic coastlines, we tentatively suggest that globally, coastal oceans (depth <180 m) together contribute ∼2.5 (1.4-3.5) Gmol Br yr −1 of CHBr 3 , excluding influences from anthropogenic sources such as coastal power stations. This flux estimate is close to current estimates of the total open ocean source. We also show that the concentration ratio of CH 2 Br 2 /CHBr 3 in seawater is a strong function of concentration (and location), with a lower CH 2 Br 2 /CHBr 3 ratio found in coastal regions near to macroalgal sources.
The gas-phase reactions of ozone with alkenes can be significant sources of free radicals (OH, HO(2) and RO(2)) in the Earth's atmosphere. In this study the total radical production and degradation products from ethene ozonolysis have been measured, under conditions relevant to the troposphere, during a series of detailed simulation chamber experiments. Experiments were carried out in the European photoreactor EUPHORE (Valencia, Spain), utilising various instrumentation including a chemical-ionisation-reaction time-of-flight mass-spectrometer (CIR-TOF-MS) measuring volatile organic compounds/oxygenated volatile organic compounds (VOCs/OVOCs), a laser induced fluorescence (LIF) system for measuring HO(2) radical products and a peroxy radical chemical amplification (PERCA) instrument measuring HO(2) + ΣRO(2). The ethene + ozone reaction system was investigated with and without an OH radical scavenger, in order to suppress side reactions. Radical concentrations were measured under dry and humid conditions and interpreted through detailed chemical chamber box modelling, incorporating the Master Chemical Mechanism (MCMv3.1) degradation scheme for ethene, which was updated to include a more explicit representation of the ethene-ozone reaction mechanism.The rate coefficient for the ethene + ozone reaction was measured to be (1.45 ± 0.25) × 10(-18) cm(3) molecules(-1) s(-1) at 298 K, and a stabilised Criegee intermediate yield of 0.54 ± 0.12 was determined from excess CO scavenger experiments. An OH radical yield of 0.17 ± 0.09 was determined using a cyclohexane scavenger approach, by monitoring the formation of the OH-initiated cyclohexane oxidation products and HO(2). The results highlight the importance of knowing the [HO(2)] (particularly under alkene limited conditions and high [O(3)]) and scavenger chemistry when deriving radical yields. An averaged HO(2) yield of 0.27 ± 0.07 was determined by LIF/model fitting. The observed yields are interpreted in terms of branching ratios for each channel within the postulated ethene ozonolysis mechanism.
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