The Quest to Quit: an Exploration of the Cessation - Relapse Cycle of Cigarette Smoking

The smoker's perspective is seldom sought in cessation research. Consequently, cessation approaches may be less effective because they are not based on assumptions and interpretations shared by those who smoke. Understanding how chronic relapsing smokers interpret their predicament could enhance cessation approaches, improving the chances for complete, permanent cessation. To generate such an understanding, five participants were recruited who had attempted to quit smoking several times. Aiming for depth rather than breadth, multiple interviews were conducted with each participant, who also kept an event diary, recording current smoking, nicotine withdrawal, lapsing and relapsing. Narratology, a biographical method of symbolic interactionism drawing on thematic, structural, and dialogic analysis, was used to elicit the participants' points of view from interview and diary data. The findings show that participants make sense of their chronic relapsing through a master narrative of 'willpower versus weakness'. Meanwhile, the tobacco control domain is largely driven by 'cost', and subsidised treatments are driven by the 'addiction' master narrative. This gap between ways of making sense of smoking and relapse can cause self-stigma, reducing the likelihood that quitting will be attempted and that quit attempts will succeed. Changes are proposed to mitigate the negative effects on self-efficacy brought about through the present approach to tobacco control. Ways to improve the effectiveness of existing treatments are suggested. Finally, the value of the narrative method is highlighted, with suggestions for its use in research where elucidating the insider point of view may improve treatment outcomes

How to Find Out Whether a 5‑Substituted Uracil Could Be a Potential DNA Radiosensitizer

Incorporated into genomic DNA, 5-substituted uracils could be employed in human cancer radiotherapy if they could be sensitized to dissociate upon reaction with hydrated electrons. Using the B3LYP/6-31++G­(d,p) method, we calculate electron affinities and energy profiles related to the dissociation of the respective anions for a series of uracil derivatives. We demonstrate that for a uracil analogue to be an efficient electron acceptor the uracil substituent has to possess significant electron-withdrawing power. On the other hand, in order to ensure effective dissociation of the anion, the chemical bond holding together the substituent and uracil residue should be relatively weak. Our theoretical predictions are in excellent agreement with the results of our negative ion photoelectron spectroscopy experiments. We propose two new potential sensitizers that seem to possess the required properties, although they have never been tested in radiobiological experiments

The Reaction Rates of O₂ with Closed-Shell and Open-Shell Al_<i>x</i>^– and Ga_<i>x</i>^– Clusters under Single-Collision Conditions: Experimental and Theoretical Investigations toward a Generally Valid Model for the Hindered Reactions of O₂ with Metal Atom Clusters

In order to characterize the oxidation of metallic surfaces, the reactions of O₂ with a number of Al_<i>x</i>^– and, for the first time, Ga_<i>x</i>^– clusters as molecular models have been investigated, and the results are presented here for <i>x</i> = 9–14. The rate coefficients were determined with FT-ICR mass spectrometry under single-collision conditions at O₂ pressures of ∼10^–8 mbar. In this way, the qualitatively known differences in the reactivities of the even- and odd-numbered clusters toward O₂ could be quantified experimentally. To obtain information about the elementary steps, we additionally performed density functional theory calculations. The results show that for both even- and odd-numbered clusters the formation of the most stable dioxide species, [M_<i>x</i>O₂]⁻, proceeds via the less stable peroxo species, [M_<i>x</i>⁺···O₂^2–]⁻, which contains M–O–O–M moieties. We conclude that the formation of these peroxo intermediates may be a reason for the decreased reactivity of the metal clusters toward O₂. This could be one of the main reasons why O₂ reactions with metal surfaces proceed more slowly than Cl₂ reactions with such surfaces, even though O₂ reactions with both Al metal and Al clusters are more exothermic than are reactions of Cl₂ with them. Furthermore, our results indicate that the spin-forbidden reactions of ³O₂ with closed-shell clusters and the spin-allowed reactions with open-shell clusters to give singlet [M_<i>x</i>⁺···O₂^2–]⁻ are the root cause for the observed even/odd differences in reactivity