Biobehavioral Influences of Anxiety, Depression, and Hostility Symptoms on Health-Related Outcomes in Patients with Heart Failure

The incidence of heart failure (HF) has increased each year as more people are living longer with heart disease and other chronic conditions. Recently, there has been much interest in the psychological dimensions of HF and the influence psychological symptoms have on the health outcomes (e.g., self-care, rehospitalization, mortality and quality of life) of patients living with HF. Patients with HF frequently experience symptoms of anxiety, depression, and hostility that may be associated with poor health outcomes. The purpose of this dissertation was to examine how psychological variables influence health outcomes of patients with HF, how psychological variables change over time, and whether different trajectories of psychological variables are associated with health outcomes. The specific aims of this dissertation were to: (1) evaluate the psychometric properties of the Brief Symptom Inventory (BSI) Hostility subscale in patients with HF; (2) determine whether anxiety, depression, and hostility predict self-care behaviors in patients with HF; and (3) describe trajectories of anxiety and depressive symptoms among patients with HF at baseline and 3 and 12 months post-baseline, and explore whether these symptom trajectories predict 1-year cardiac event-free survival and physical health-related quality of life (P-HRQOL). Secondary analyses of longitudinal data from a large, multi-region registry representing the Midwest, Southwest, Southeast, Northwest and Northeast United States (Heart Failure Quality of Life Trialists Collaborative) were conducted. Data from three subsets of participants enrolled in the Collaborative with complete data on the variables of interest comprised the samples for the three studies in this dissertation. In the first study, a psychometric evaluation of the BSI Hostility subscale was conducted using data from 345 patients with HF. The subscale demonstrated adequate internal consistency reliability (Cronbach’s alpha = .77) and construct validity. In the second longitudinal study of 214 patients with HF, baseline anxiety, depression, and hostility did not predict self-care at 12 months; however, higher perceived social support predicted greater self-care. In the third study, baseline, 3-month, and 12-month data from 597 patients with HF were used to examine the association of anxiety and depression trajectories with one-year cardiac event-free survival and P-HRQOL in patients with HF. Distinct trajectories of anxiety and depression predicted mortality, hospital readmission, and P-HRQOL. The findings of these studies filled some gaps in our understanding regarding how anxiety, depression, and hostility influence health outcomes of patients with HF. The findings suggest how a measure of hostility may be improved to assess hostility in patients with HF and the importance of assessing psychological symptoms routinely in order to identify changes in these symptoms. Results showed that psychological variables did not predict self-care, a component of risk reduction in improving health outcomes among patients with HF, but that social support, an important psychosocial variable, was a strong predictor of self-care. Trajectories of psychological variables were significant predictors of health outcomes in patients with HF at 1-year follow-up. Implications include the importance of monitoring psychological symptoms over time. A better understanding of how psychological symptoms change is meaningful, as it affords clinicians the opportunity for timely interventions designed to reduce the risk of adverse events and improve health outcomes. Even though numerous studies exist which examine psychological symptoms and health outcomes in patients with HF, there are very few longitudinal studies investigating trajectories of psychological symptoms in this population. Subsequently, more research is needed to investigate psychological symptom trajectories and identify high risk groups. In addition, the design and testing of interventions aimed at reducing psychological symptoms is critical to improve health outcomes in patients with HF

Comparative study of FeCr2S4 and FeSc2S4: Spinels with orbitally active A site

Using first-principles density functional calculations, we perform a comparative study of two Fe based spinel compounds, FeCr2S4 and FeSc2S4. Though both systems contain an orbitally active A site with an Fe2+ ion, their properties are rather dissimilar. Our study unravels the microscopic origin of their behavior driven by the differences in hybridization of Fe d states with Cr/Sc d states and S p states in the two cases. This leads to important differences in the nature of the magnetic exchanges as well as the nearest versus next nearest neighbor exchange parameter ratios, resulting into significant frustration effects in FeSc2S4 which are absent in FeCr2S4.Comment: 5 pages, 4 figures Phys Rev B (rapid commun) to appear (2010

Analysis of spin density wave conductivity spectra of iron pnictides in the framework of density functional theory

The optical conductivity of LaFeAsO, BaFe$_2$As$_2$, SrFe$_2$As$_2$, and EuFe$_2$As$_2$ in the spin-density wave (SDW) state is investigated within density functional theory (DFT) in the framework of spin-polarized generalized gradient approximation (GGA) and GGA+U. We find a strong dependence of the optical features on the Fe magnetic moments. In order to recover the small Fe magnetic moments observed experimentally, GGA+$U_{\rm eff}$ with a suitable choice of negative on-site interaction $U_{\rm eff}=U-J$ was considered. Such an approach may be justified in terms of an overscreening which induces a relatively small U compared to the Hund's rule coupling J, as well as a strong Holstein-like electron-phonon interaction. Moreover, reminiscent of the fact that GGA+$U_{\rm eff}$ with a positive $U_{\rm eff}$ is a simple approximation for reproducing a gap with correct amplitude in correlated insulators, a negative $U_{\rm eff}$ can also be understood as a way to suppress magnetism and mimic the effects of quantum fluctuations ignored in DFT calculations. With these considerations, the resulting optical spectra reproduce the SDW gap and a number of experimentally observed features related to the antiferromagnetic order. We find electronic contributions to excitations that so far have been attributed to purely phononic modes. Also, an orbital resolved analysis of the optical conductivity reveals significant contributions from all Fe 3d orbitals. Finally, we observe that there is an important renormalization of kinetic energy in these SDW metals, implying that the effects of correlations cannot be neglected.Comment: 8 pages, 4 figures; recalculated spectra for U_eff=-1.9 eV for better comparison to experimental results, added discussion of the role of U and J in LDA+

Effect of dopant atoms on local superexchange in cuprate superconductors: a perturbative treatment

Recent scanning tunneling spectroscopy experiments have provided evidence that dopant impurities in high- Tc superconductors can strongly modify the electronic structure of the CuO2 planes nearby, and possibly influence the pairing. To investigate this connection, we calculate the local magnetic superexchange J between Cu ions in the presence of dopants within the framework of the three-band Hubbard model, up to fifth-order in perturbation theory. We demonstrate that the sign of the change in J depends on the relative dopant-induced spatial variation of the atomic levels in the CuO2 plane, contrary to results obtained within the one-band Hubbard model. We discuss some realistic cases and their relevance for theories of the pairing mechanism in the cupratesComment: 5 pages, 4 figures, revised versio

Origin of the insulating state in honeycomb iridates and rhodates

A burning question in the emerging field of spin-orbit driven insulating iridates, such as Na2IrO3 and Li2IrO3 is whether the observed insulating state should be classified as a Mott-Hubbard insulator derived from a half-filled relativistic j_eff=1/2 band or as a band insulator where the gap is assisted by spin-orbit interaction, or Coulomb correlations, or both. The difference between these two interpretations is that only for the former, strong spin-orbit coupling (lambda >~ W, where W is the band width) is essential. We have synthesized the isostructural and isoelectronic Li2RhO3 and report its electrical resistivity and magnetic susceptibility. Remarkably it shows insulating behavior together with fluctuating effective S=1/2 moments, similar to Na2IrO3 and Li2IrO3, although in Rh4+ (4d5) the spin-orbit coupling is greatly reduced. We show that this behavior has non-relativistic one-electron origin (although Coulomb correlations assist in opening the gap), and can be traced down to formation of quasi-molecular orbitals, similar to those in Na2IrO3.Comment: 7 pages, 7 figure

Understanding the Goals of Everyday Instrumental Actions Is Primarily Linked to Object, Not Motor-Kinematic, Information: Evidence from fMRI

Prior research conceptualised action understanding primarily as a kinematic matching of observed actions to own motor representations but has ignored the role of object information. The current study utilized fMRI to identify (a) regions uniquely involved in encoding the goal of others' actions, and (b) to test whether these goal understanding processes draw more strongly on regions involved in encoding object semantics or movement kinematics. Participants watched sequences of instrumental actions while attending to either the actions' goal (goal task), the movements performed (movement task) or the objects used (object task). The results confirmed, first, a unique role of the inferior frontal gyrus, middle temporal gyrus and medial frontal gyrus in action goal understanding. Second, they show for the first time that activation in the goal task overlaps directly with object- but not movement-related activation. Moreover, subsequent parametric analyses revealed that movement-related regions become activated only when goals are unclear, or observers have little action experience. In contrast to motor theories of action understanding, these data suggest that objects-rather than movement kinematics-carry the key information about others' actions. Kinematic information is additionally recruited when goals are ambiguous or unfamiliar

Large-Scale Regular Morphological Patterns in the Radio Jet of NGC 6251

We report on large-scale, regular morphological patterns found in the radio jet of the nearby radio galaxy NGC 6251. Investigating morphological properties of this radio jet from the nucleus to a radial distance of $\sim$ 300 arcsec ($\approx$ 140 kpc) mapped at 1662 MHz and 4885 MHz by Perley, Bridle, & Willis, we find three chains, each of which consists of five radio knots. We also find that eight radio knots in the first two chains consist of three small sub-knots (the triple-knotty substructures). We discuss the observational properties of these regular morphological patterns.Comment: 8 figures, 15 pages, accepted for publication in A