In situ inelastic neutron scattering studies of the rotational and translational dynamics of molecular hydrogen adsorbed in single-wall carbon nanotubes (SWNTs)

Inelastic neutron scattering (INS) spectra were measured in situ from progressively increased amounts of para-hydrogen physisorbed in bundles of single-walled carbon nanotubes at temperatures in the vicinity of 20 K. INS from the bound H2 molecules consists of two distinct parts carrying complementary information. In the low energy and momentum transfer region, at about 14.5 meV we observe a sharp line corresponding to rotational transitions between the ground para-J = 0 state and the ground ortho-J = 1 state without change of the translational state of the molecular centre of mass (CoM). This we call the “bound” spectrum. At higher energy transfers, a series of broad peaks are observed, corresponding to rotational transitions between the para-J = 0 state and different ortho-states (J = 1, 3, 5, … ,) shifted out in energy transfer by an amount equal to the CoM recoil energy. This we call the “recoil” spectrum. Both parts of each spectrum are analysed using the Young and Koppel model. From the “bound” spectrum we estimate the mean height of the barrier to rotation and the mean square displacements of the molecules accommodated at different adsorption sites. The “recoil” spectrum allows us to derive the mean translational kinetic energy of the adsorbed hydrogen as a function of the surface concentration

Nutrition in adolescents: physiology, metabolism, and nutritional needs

.Adolescence is the period of development that begins at puberty and ends in early adulthood. Most commonly, adolescence is divided into three developmental periods: early adolescence (10-14 years of age), late adolescence (15-19 years of age), and young adulthood (20-24 years of age). Adolescence is marked by physical and sexual maturation, social and economic independence, development of identity, acquisition of skills needed to carry out adult relationships and roles, and the capacity for abstract reasoning. Adolescence is characterized by a rapid pace of growth that is second only to that of infancy. Nutrition and the adolescent transition are closely intertwined, since eating patterns and behaviors are influenced by many factors, including peer influences, parental modeling, food availability, food preferences, cost, convenience, personal and cultural beliefs, mass media, and body image. Here, we describe the physiology, metabolism, and nutritional requirements for adolescents and pregnant adolescents, as well as nutrition-related behavior and current trends in adolescent nutrition. We conclude with thoughts on the implications for nutrition interventions and priority areas that would require further investigation

Genetic fingerprinting

Genetic fingerprintin