The Role of the Mass Media in Women’s Infant Feeding Decisions: A Dissertation

Breastfeeding has been established as providing the best and most complete nutrition for newborns, as this method promotes the infant’s health and supports infant growth (American Academy of Pediatrics [AAP], 2005). Mass media have been suggested as powerful and universal means of communication with the potential to impact social norms. Thus, this qualitative descriptive study explored, within the context of the Socioecological Framework, women’s decision making on whether to breastfeed or bottle-feed their infants and the effect of mass media on their decision. Data were collected in individual audiotaped interviews with participants recruited from the Massachusetts Breastfeeding Coalition and UMass Memorial Medical Center. Interview data were compared to text and visual representation from 12 Internet sites on parenting and infant feeding. Data analysis was conducted simultaneously with data collection and was continued until saturation was achieved. The comparison findings demonstrated that the emerging themes from the participant interviews reflected the information represented on the Internet sites. The main theme Media Matters Not suggested that mass media did not influence infant feeding decisions for this group of mothers. What did have an important impact on infant feeding decisions was the information and emotional support provided by partners, family, and HCPs (subtheme of Influences on Decisions). The participants offered suggestions of media messages they would like see in the future such as public service announcements of women breastfeeding their infants. In addition, the participants discussed media issues that had potential for influencing infant feeding decisions (Media Messages—Good and Bad), emphasized the need for public opinion to be altered so that breastfeeding in public would be viewed as more acceptable (Community/Public Opinions), and described suggestions for enhancing media messages about breastfeeding (Recommendations for Future Media Messages). The implications for nursing practice, public policy, and future research related to the topic were discussed

Ab initio molecular dynamics simulations of Aluminum solvation

The solvation of Al and its hydrolyzed species in water clusters has been studied by means of ab initio molecular dynamics simulations. The hexa-hydrate aluminum ion formed a stable complex in the finite temperature cluster simulation of one aluminum ion and 16 waters. The average dipole moment of strongly polarized hydrated water molecules in the first solvation shell of the hexa-hydrate aluminum ion was found to be 5.02 Debye. The deprotonated hexa-hydrate complex evolves into a tetra-coordinated aluminate ion with two water molecules in the second solvation shell forming hydrogen bonds to the hydroxyl groups in agreement with the observed coordination.Comment: 12 pages in Elsevier LaTeX, 5 figures in Postscript, 2 last figures are in color, submitted to Chemical Physics Letter

Reaction Energetics and ¹³C Fractionation of Alanine Transamination in the Aqueous and Gas Phases

The alanine transaminase (ALT) enzyme catalyzes the transfer of an amino group from alanine to α-ketoglutarate to produce pyruvate and glutamate. Isotope fractionation factors (IFFs) for the reaction ⁺H₃NCH(CH₃)COO⁻ + ⁻OOCCH₂CH₂C(O)COO⁻ ↔ CH₃C(O)COO⁻ + ⁻H₃NCH(CH₂CH₂COO⁻)COO⁻ (zwitterionic neutral alanine + doubly deprotonated α-ketoglutarate ↔ pyruvate + zwitterionic glutamate anion) were calculated from the partition functions of explicitly and implicitly solvated molecules at 298 K. Calculations were done for alanine (non-charge separated, zwitterion, deprotonated,), pyruvic acid (neutral, deprotonated), glutamic acid (non-charge separated, zwitterion, deprotonated, doubly deprotonated), and α-ketoglutaric acid (neutral, deprotonated, doubly deprotonated). The computational results, calculated from gas phase and aqueous optimized clusters with explicit H₂O molecules at the MP₂/aug-cc-pVDZ and MP₂/aug-cc-pVDZ/COSMO levels, respectively, predict that substitution of ¹³C at the C2 position of alanine and pyruvic acid and their various forms leads to the C2 position of pyruvic acid/pyruvate being enriched in ¹³C/¹²C ratio by 9 ‰. Simpler approaches that estimate the IFFs based solely on changes in the zero-point energies (ZPEs) are consistent with the higher-level model. ZPE-based IFFs calculated for simple analogues formaldehyde and methylamine (analogous to the C₂ positions of pyruvate and alanine, respectively) predict a ¹³C enrichment in formaldehyde of 7 to 8 ‰ at the MP₂/aug-cc-pVDZ and aug-cc-pVTZ levels. A simple predictive model using canonical functional group frequencies and reduced masses for ¹³C exchange between R₂C=O and R₂CH-NH₂ predicted enrichment in R₂C=O that is too large by a factor of two, but is qualitatively accurate compared with the more sophisticated models. Our models are all in agreement with the expectation that pyruvate and formaldehyde will be preferentially enriched in ¹³C due to the strength of their >C=O bond relative to that of the ≡C-NH₂ in alanine and methylamine. ¹³C/¹²C substitution is also modeled at the methyl and carboxylic acid sites of alanine and pyruvic acid, respectively

Symmetry Breaking with the SCAN Density Functional Describes Strong Correlation in the Singlet Carbon Dimer

The SCAN (strongly constrained and appropriately normed) meta-generalized gradient approximation (meta-GGA), which satisfies all 17 exact constraints that a meta-GGA can satisfy, accurately describes equilibrium bonds that are normally correlated. With symmetry breaking, it also accurately describes some sd equilibrium bonds that are strongly correlated. While sp equilibrium bonds are nearly always normally correlated, the C2 singlet ground state is known to be a rare case of strong correlation in an sp equilibrium bond. Earlier work that calculated atomization energies of the molecular sequence B2, C2, O2, and F2 in the local spin density approximation (LSDA), the Perdew-Burke-Ernzerhof (PBE) GGA, and the SCAN meta-GGA, without symmetry breaking in the molecule, found that only SCAN was accurate enough to reveal an anomalous under-binding for C2. This work shows that spin symmetry breaking in singlet C2, the appearance of net up- and down-spin densities on opposite sides (not ends) of the bond, corrects that under-binding, with a small SCAN atomization-energy error more like that of the other three molecules, suggesting that symmetry-breaking with an advanced density functional might reliably describe strong correlation. This article also discusses some general aspects of symmetry breaking, and the insights into strong correlation that symmetry-breaking can bring.Comment: 10 pages, 3 figures, 1 Tabl

Does Spin-Orbit Coupling Effect Favor Planar Structures for Small Platinum Clusters?

We have performed full-relativistic density functional theory calculations to study the geometry and binding energy of different isomers of free platinum clusters Pt$_{n}$ ($n=4-6$) within the spin multiplicities from singlet to nonet. The spin-orbit coupling effect has been discussed for the minimum-energy structures, relative stabilities, vibrational frequencies, magnetic moments, and the highest occupied and lowest unoccupied molecular-orbital gaps. It is found in contrast to some of the previous calculations that 3-dimentional configurations are still lowest energy structures of these clusters, although spin-orbit effect makes some planar or quasi-planar geometries more stable than some other 3-dimentional isomers