Minor and subthreshold depressive disorders in Alzheimer's disease: a systematic review and meta-analysis of prevalence studies

Background: Depressive symptoms are common in Alzheimer's disease (AD) and negatively impact patient well-being. The main aim of the present study was to establish summary estimates for the prevalence of minor depressive disorder (MinD) and subthreshold depression in AD and synthesise evidence on prognosis and management of these symptoms in order to inform clinical guidelines. / Methods: Systematic review and meta-analysis of cross-sectional and longitudinal studies of prevalence, prognosis, and treatments for minor and subthreshold depression in AD. We searched MEDLINE, Embase, PsycINFO and CINAHL. We included studies that reported prevalence of subthreshold depressive disorders and those reporting data on validity of diagnostic criteria, mechanisms, or randomised controlled clinical trials (RCTs) testing effectiveness of interventions. Estimates of prevalence were pooled using random-effects meta-analyses. Two authors screened articles and independently extracted data on study characteristics. / Results: We reviewed 5671 abstracts, retrieved 621 full text articles and included a total of 15 studies. Pooling data from 10 studies showed that prevalence for MinD in AD was 22.0% (95% CI 16.0 to 28.0). Prevalence for a clinical diagnosis of MinD (DSM-III-R and DSM-IV) was 26.0% (95% CI 20.0 to 32.0; 6 studies). People with MinD experienced higher levels of neuropsychiatric symptoms, functional and cognitive decline, although studies remain cross-sectional. Neither sertraline nor a carer intervention were effective in reducing symptoms. / Conclusion: This review finds that MinD is prevalent in people with a diagnosis of AD and requires clinical attention. Research is warranted to develop effective interventions to treat and prevent these symptoms

Size dependence of the photoinduced magnetism and long-range ordering in Prussian blue analog nanoparticles of rubidium cobalt hexacyanoferrate

Nanoparticles of rubidium cobalt hexacyanoferrate (Rb$_j$Co$_k$[Fe(CN)$_6$]$_l \cdot n$H$_2$O) were synthesized using different concentrations of the polyvinylpyrrolidone (PVP) to produce four different batches of particles with characteristic diameters ranging from 3 to 13 nm. Upon illumination with white light at 5 K, the magnetization of these particles increases. The long-range ferrimagnetic ordering temperatures and the coercive fields evolve with nanoparticle size. At 2 K, particles with diameters less than approximately 10 nm provide a Curie-like magnetic signal.Comment: 10 pages, 6 figures in text, expanded text and dat

Simulation study of pressure and temperature dependence of the negative thermal expansion in Zn(CN)(2)

12 pages, 16 figures12 pages, 16 figures12 pages, 16 figures12 pages, 16 figure

Are Simple Real Pole Solutions Physical?

We consider exact solutions generated by the inverse scattering technique, also known as the soliton transformation. In particular, we study the class of simple real pole solutions. For quite some time, those solutions have been considered interesting as models of cosmological shock waves. A coordinate singularity on the wave fronts was removed by a transformation which induces a null fluid with negative energy density on the wave front. This null fluid is usually seen as another coordinate artifact, since there seems to be a general belief that that this kind of solution can be seen as the real pole limit of the smooth solution generated with a pair of complex conjugate poles in the transformation. We perform this limit explicitly, and find that the belief is unfounded: two coalescing complex conjugate poles cannot yield a solution with one real pole. Instead, the two complex conjugate poles go to a different limit, what we call a ``pole on a pole''. The limiting procedure is not unique; it is sensitive to how quickly some parameters approach zero. We also show that there exists no improved coordinate transformation which would remove the negative energy density. We conclude that negative energy is an intrinsic part of this class of solutions.Comment: 13 pages, 3 figure

Backreaction from non-conformal quantum fields in de Sitter spacetime

We study the backreaction on the mean field geometry due to a non-conformal quantum field in a Robertson-Walker background. In the regime of small mass and small deviation from conformal coupling, we compute perturbatively the expectation value of the stress tensor of the field for a variety of vacuum states, and use it to obtain explicitly the semiclassical gravity solutions for isotropic perturbations around de Sitter spacetime, which is found to be stable. Our results show clearly the crucial role of the non-local terms that appear in the effective action: they cancel the contribution from local terms proportional to the logarithm of the scale factor which would otherwise become dominant at late times and prevent the existence of a stable self-consistent de Sitter solution. Finally, the opposite regime of a strongly non-conformal field with a large mass is also considered.Comment: 31 page