Reactive collisions in quadrupole cells. 3: H/D exchange reactions of protonated aromatic amines with ND3

The H/D exchange reactions of a variety of protonated aromatic amines with ND3 in the collision cell of a hybrid BEqQ tandem mass spectrometer have been studied. The MH+ ions were prepared by CH4, i-C4H10, and NH3 chemical ionization (CI) and, for some amines, by fast-atom bombardment (FAB). Evidence is presented that the kinetic energy of the incident ion as well as its internal energy must be dissipated by nonexchanging collisions before exchange occurs; once deactivated the MH+ ions exchange efficiently, which leads, in most cases, to [MH]1 dx ions in which all active hydrogens have been exchanged. The MH1 ion of 1,3-phenylenediamine formed by gas-phase CI exchanges only very slightly with ND3 whereas a significant fraction of the MH+ ions formed by FAB exchange efficiently. This difference is rationalized in terms of dominant formation of the ring-protonated species in gas-phase CI reactions and significant formation of the N-protonated species by FAB with only the N-protonated species exchanging efficiently. Similar, although less pronounced, differences are observed for the MH+ ion of m-anisidine. In a number of cases apparent exchange of aromatic hydrogens also is observed. Evidence is presented for the interchange of ring and amine hydrogens in protonated aromatic amines and it is suggested that only the N-protonated species undergoes significant exchange with ND3

Body Image Perception and the Risk of Unhealthy Behaviours among University Student

Background: In this study we sought to determine whether dissatisfaction with one’s body was associated with unhealthy behaviours among University students. Subjects and Methods: A cross-section of 383 male and female students recruited from the general University population completed a questionnaire consisting of socio-demographic items, Eating Attitudes Test (EATS-26), Body Shape Questionnaire (BSQ-16), Body Silhouette Chart, Rosenberg Self-Esteem Scale (RSE) and the Centre for Epidemiologic Studies depression scale (CES-D). Results: Overall, 4.2% of participants reported to have been diagnosed with an eating problem. Females had significantly higher EATS-26, BSQ-16 and RSE scores than males. They were significantly more likely than males to choose silhouettes that were underweight to represent their current or desired body sizes and to engage in dieting behaviours. Additionally, persons who reported being diagnosed with an eating disorder were significantly more likely than those not diagnosed to report binging, bulimic and other eating-related behaviours (p < 0.01). For both males and females, perceived body image was significantly and positively associated with BSQ-16, EATS-26, and CES–D and inversely associated with RSE scores. Females of African-descent were significantly more likely than those of East Indian- descent and other races to report higher weights and to select larger silhouettes to represent their current body figure. Conclusions: Among participants, body dissatisfaction was associated with increased risk for depression, lower self-esteem, disordered eating and other weight related behaviours