Influence of reducing anterior pelvic tilt on shoulder posture and the electromyographic activity of scapular upward rotators.

BACKGROUND: Modifications of posture in a segment may influence the posture of adjacent and nonadjacent segments and muscular activity. The spine-shoulder and spine-pelvis relationships suggest that the pelvis may influence shoulder posture. OBJECTIVE: To investigate the effect of the active reduction of the anterior pelvic tilt on shoulder and trunk posture during static standing posture and on the electromyographic activity of the scapular upward rotators during elevation and lowering of the arm. METHODS: Thirty-one young adults were assessed in a relaxed standing position and a standing position with 30% active reduction of the anterior pelvic tilt. The pelvic tilt, trunk posture, and forward shoulder posture during the static standing posture and the electromyographic activity during elevation and lowering of the arm were assessed. RESULTS: Paired t-tests indicated that the active reduction of the anterior pelvic tilt reduced the trunk extension (MD=1.09; 95%CI=-2.79 to -1.03). There were no effects on the forward shoulder posture (MD=0.09; 95%CI=-0.92 to 1.09). Repeated measures of analyses of variance indicated an increase in lower trapezius electromyographic activity (MD=3.6; 95%CI=1.28 to 5.92). There was a greater reduction in upper trapezius activity after pelvic tilt reduction during arm elevation (MD=1.52%; 95%CI=-2.79 to -0.25) compared to that during the lowering phase. There were no effects of pelvic tilt reduction on the electromyographic activity of the serratus anterior (MD=3.26; 95%CI=-3.36 to 9.87). CONCLUSION: The influence of pelvic posture on the trunk posture and lower trapezius activation should be considered when assessing or planning exercise for individuals with shoulder or trunk conditions.

Mechanistic Aspects of Phosphate Diester Cleavage Assisted by Imidazole. A Template Reaction for Obtaining Aryl Phosphoimidazoles.

Phosphoimidazole-containing compounds are versatile players in biological and chemical processes. We explore catalytic and mechanistic criteria for the efficient formation of cyclic aryl phosphoimidazoles in aqueous solution, viewed as a template reaction for the in situ synthesis of related compounds. To provide a detailed analysis for this reaction a series of o-(2'-imidazolyl)naphthyl (4-nitrophenyl) phosphate isomers were examined to provide a basis for analysis of both mechanism and the influence of structural factors affecting the nucleophilic attack of the imidazolyl group on the phosphorus center of the substrate. Formation of the cyclic aryl phosphoimidazoles was probed by NMR and ESI-MS techniques. Kinetic experiments show that cyclization is faster under alkaline conditions, with an effective molarity up to 2900 M for the imidazolyl group, ruling out competition from external nucleophiles. Heavy atom isotope effect and computational studies show that the reaction occurs through a SN2(P)-type mechanism involving a pentacoordinated phosphorus TS, with apical positions occupied by the incoming imidazolyl nucleophile and the p-nitrophenolate leaving group. The P-O bond to the leaving group is about 50-60% broken in the transition state.

Effective targeting of proton transfer at ground and excited states of ortho-(2'-imidazolyl)naphthol constitutional isomers.

Steady-state and time-resolved spectroscopy and quantum chemical computational studies were employed to investigate ground and excited state proton transfer of a novel series of ortho-(1H-imidazol-2-yl)naphthol constitutional isomers: 1-(1H-imidazol-2-yl)naphthalen-2-ol (1NI2OH), 2-(1H-imidazol-2-yl)naphthalen-1-ol (2NI1OH) and 3-(1H-imidazol-2-yl)naphthalen-2-ol (3NI2OH). Proper Near Attack Conformations (NACs) involving a strong intramolecular hydrogen bond between the naphthol moiety and the ortho-imidazole group account for the highest ground state acidity of 2NI1OH compared with 1NI2OH and 3NI2OH. Moreover, ESIPT for 2NI1OH and 3NI2OH is further associated with planar chelate H-ring formation whereas 1NI2OH shows the highest ESIPT barrier and a noncoplanar imidazole group. In addition to energetic and structural requirements, the final state also depends on electronic configuration of the ESIPT product with the neutral 3NI2OH showing an ICT effect that correlates with the excited state pKa of the cationic species.