Photolysis of the d-glycosides: α benzylfructofuranoside, β benzylfructopyranoside,and α and β phenyl,benzyl and β phenylethyl glucosides; and the bearing of the data upon the transfer of energy within molecules

Direct absorption of light by glycosides dissolved in water has been discovered to produce changes in optical activities and formation of material which reduces the Shaffer, Hartmann, Somogyi reagent. Comparison of these measurements indicates in many cases the same products as are formed by hydrolysis in acid. The β glucosides and α fructoside, however, apparently give optically inactive photolytic products.Absorption spectra were obtained for α benzylfructofuranoside and β benzylfructopyranoside, and were found to be the same in the near ultraviolet as those previously obtained for benzyl glucosides and benzyl alcohol.The absorption spectrum for freshly purified fructose gives a deeper minimum about λ240 mμ than the previously reported values. The latter, however, were approached when the dry crystals had stood in air for several months although no change occurred in their sp.rot., m.p. or general apperance.All the glycosides studied were white crystalline compounds. Less than five per cent. of the ultraviolet light of λ254 mμ they absorb produces reaction; nevertheless, the apparatus and procedures available were adequate to study the reaction conveniently in monochromatic light of this wave-length.The absorption spectra, the products of photolysis, and the quantum yields, the latter based on the reducing material formed, lead to the hypothesis that the photochemical reaction is produced by an intramolecular transfer of absorbed energy from the aglycone to the hemiacetal oxygen bridge which is the reactive center. The efficiency of this transfer is, as expected, greater for benzyl than for phenylethyl glucosides but phenyl glucosides, contrariwise, are the least efficient.The structure and energy possessed by the glycoside outside the aglycone have no measurable effect on the efficiency of the photochemical reaction when followed by measuring the reducing material produced although they change up to one hundred thousand fold the rates of the thermal hydrolyses in acid.     

Implementing a school-based physical activity program: process evaluation and impact on teachers’ confidence,perceived barriers and self-perceptions

Introduction: Secondary schools have the potential to promote health-related fitness (HRF) and physical activity within and outside school hours. As such, schools are often chosen as the setting to implement child and adolescent physical activity programs. School-based programs often utilise teachers as delivery agents, but few studies examine effects on teacher-level outcomes.

Purpose: The primary aim of this study was to determine the impact of teacher training embedded within a physical activity intervention on teacher-level outcomes. The secondary aim of this study was to evaluate process data, including implementation, satisfaction and fidelity.

Methods: Resistance Training for Teens (RT for Teens) was evaluated using a cluster randomised controlled trial in 16 secondary schools. Teachers (N?=?44; 48% female/52% male; mean?±?SD years teaching experience?=?10.6?±?8.0) from 16 secondary schools were assessed at baseline. Intervention group teachers (i.e. from eight schools) delivered a structured school-based physical activity program over 10-weeks. Teacher outcomes included confidence to teach health-related fitness (HRF) activities, perceived barriers to teaching HRF activities, and perceived fitness. Detailed process evaluation data were also collected. Assessments were conducted at baseline and 6-months (post-program), and outcomes were assessed using repeated measures analysis of variance.

Results: There was a positive group-by-time effect for the confidence composite score (p?=?.010, partial eta squared?=?0.29), but no effects for the two (contextual, interpersonal) barrier composite scores. Also, there was a significant effect for perceived ‘general fitness’ (p?=?0.044, partial eta squared?=?0.13), but not for specific fitness subdomains. Teachers were highly satisfied with both the training and the program, believing it was beneficial for students. Resource usage and adherence to the SAAFE (Supportive, Active, Autonomous, Fair, Enjoyable) delivery principles was high.

Conclusion: RT for Teens improved teachers’ confidence and perceived fitness. These findings highlight the potential for high-quality teacher training and program delivery to positively influence teacher-level outcomes. This may provide support for the use of teacher professional development to improve HRF-related pedagogy.