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There is limited knowledge on vitamin D status of children residing in the Andes and its association with undernutrition. We evaluated the vitamin D status of children residing in a low socio-economic status (SES) setting in the Ecuadorian Andes and assessed the association between vitamin D status, stunting and underweight. We hypothesized that children who were underweight would have lower serum 25-hydroxyvitamin D (25(OH)D) levels and lower 25(OH)D levels would be associated with a higher risk of stunting.
We conducted a cross-sectional secondary analysis of a randomized controlled trial, the Vitamin A, Zinc and Pneumonia study. Children had serum 25(OH)D concentrations measured. A sensitivity analysis was undertaken to determine a vitamin D cut-off specific for our endpoints. Associations between serum 25(OH)D and underweight (defined as weight-for-age Z-score≤−1) and stunting (defined as height-for-age Z-score≤−2) were assessed using multivariate logistic regression.
Children residing in five low-SES peri-urban neighbourhoods near Quito, Ecuador.
Children (n 516) aged 6–36 months.
Mean serum 25(OH)D concentration was 58·0 (sd 17·7) nmol/l. Sensitivity analysis revealed an undernutrition-specific 25(OH)D cut-off of <42·5 nmol/l; 18·6 % of children had serum 25(OH)D<42·5 nmol/l. Children who were underweight were more likely to have serum 25(OH)D<42·5 nmol/l (adjusted OR (aOR)=2·0; 95 % CI 1·2, 3·3). Children with low serum 25(OH)D levels were more likely to be stunted (aOR=2·8; 95 % CI 1·6, 4·7).
Low serum 25(OH)D levels were more common in underweight and stunted Ecuadorian children.
Research has long noted higher prevalence rates of suicidal thoughts and behaviors among individuals with psychotic symptoms. Major theories have proposed several explanations to account for this association. Given the differences in the literature regarding the operationalization of psychosis and sample characteristics, a quantitative review is needed to determine to what extent and how psychosis confers risk for suicidality.
We searched PsycInfo, PubMed, and GoogleScholar for studies published before 1 January 2016. To be included in the analysis, studies must have used at least one psychosis-related factor to longitudinally predict suicide ideation, attempt, or death. The initial search yielded 2541 studies. Fifty studies were retained for analysis, yielding 128 statistical tests.
Suicide death was the most commonly studied outcome (43.0%), followed by attempt (39.1%) and ideation (18.0%). The median follow-up length was 7.5 years. Overall, psychosis significantly conferred risk across three outcomes, with weighted mean ORs of 1.70 (1.39–2.08) for ideation, 1.36 (1.25–1.48) for attempt, and 1.40 (1.14–1.72) for death. Detailed analyses indicated that positive symptoms consistently conferred risk across outcomes; negative symptoms were not significantly associated with ideation, and were protective against death. Some small moderator effects were detected for sample characteristics.
Psychosis is a significant risk factor for suicide ideation, attempt, and death. The finding that positive symptoms increased suicide risk and negative symptoms seemed to decrease risk sheds light on the potential mechanisms for the association between psychosis and suicidality. We note several limitations of the literature and offer suggestions for future directions.
We used the Wisconsin Ultraviolet Photo-Polarimeter Experiment during the Astro-2 mission aboard the Space Shuttle Endeavour, to obtain ultraviolet spectropolarimetry of three classical novae that had recently gone into outburst. All three novae appear to have intrinsic polarization, with polarization changes across emission lines. This result indicates that, geometrically, the ejecta were quite aspherical.
A history of self-injurious thoughts and behaviors (SITBs) is consistently cited as one of the strongest predictors of future suicidal behavior. However, stark discrepancies in the literature raise questions about the true magnitude of these associations. The objective of this study is to examine the magnitude and clinical utility of the associations between SITBs and subsequent suicide ideation, attempts, and death.
We searched PubMed, PsycInfo, and Google Scholar for papers published through December 2014. Inclusion required that studies include at least one longitudinal analysis predicting suicide ideation, attempts, or death using any SITB variable. We identified 2179 longitudinal studies; 172 met inclusion criteria.
The most common outcome was suicide attempt (47.80%), followed by death (40.50%) and ideation (11.60%). Median follow-up was 52 months (mean = 82.52, s.d. = 102.29). Overall prediction was weak, with weighted mean odds ratios (ORs) of 2.07 [95% confidence interval (CI) 1.76–2.43] for ideation, 2.14 (95% CI 2.00–2.30) for attempts, and 1.54 (95% CI 1.39–1.71) for death. Adjusting for publication bias further reduced estimates. Diagnostic accuracy analyses indicated acceptable specificity (86–87%) and poor sensitivity (10–26%), with areas under the curve marginally above chance (0.60–0.62). Most risk factors generated OR estimates of <2.0 and no risk factor exceeded 4.5. Effects were consistent regardless of sample severity, sample age groups, or follow-up length.
Prior SITBs confer risk for later suicidal thoughts and behaviors. However, they only provide a marginal improvement in diagnostic accuracy above chance. Addressing gaps in study design, assessment, and underlying mechanisms may prove useful in improving prediction and prevention of suicidal thoughts and behaviors.
Intracranial volume (ICV) has been proposed as a measure of maximum lifetime brain size. Accurate ICV measures require neuroimaging which is not always feasible for epidemiologic investigations. We examined head circumference as a useful surrogate for ICV in older adults.
99 older adults underwent Magnetic Resonance Imaging (MRI). ICV was measured by Statistical Parametric Mapping 8 (SPM8) software or Functional MRI of the Brain Software Library (FSL) extraction with manual editing, typically considered the gold standard. Head circumferences were determined using standardized tape measurement. We examined estimated correlation coefficients between head circumference and the two MRI-based ICV measurements.
Head circumference and ICV by SPM8 were moderately correlated (overall r = 0.73, men r = 0.67, women r = 0.63). Head circumference and ICV by FSL were also moderately correlated (overall r = 0.69, men r = 0.63, women r = 0.49).
Head circumference measurement was strongly correlated with MRI-derived ICV. Our study presents a simple method to approximate ICV among older patients, which may prove useful as a surrogate for cognitive reserve in large scale epidemiologic studies of cognitive outcomes. This study also suggests the stability of head circumference correlation with ICV throughout the lifespan.
Specific roles of individual CDPKs vary, but in general they mediate essential biological functions necessary for parasite survival. A comparative analysis of the structure-activity relationships (SAR) of Neospora caninum, Eimeria tenella and Babesia bovis calcium-dependent protein kinases (CDPKs) together with those of Plasmodium falciparum, Cryptosporidium parvum and Toxoplasma gondii was performed by screening against 333 bumped kinase inhibitors (BKIs). Structural modelling and experimental data revealed that residues other than the gatekeeper influence compound–protein interactions resulting in distinct sensitivity profiles. We subsequently defined potential amino-acid structural influences within the ATP-binding cavity for each orthologue necessary for consideration in the development of broad-spectrum apicomplexan CDPK inhibitors. Although the BKI library was developed for specific inhibition of glycine gatekeeper CDPKs combined with low inhibition of threonine gatekeeper human SRC kinase, some library compounds exhibit activity against serine- or threonine-containing CDPKs. Divergent BKI sensitivity of CDPK homologues could be explained on the basis of differences in the size and orientation of the hydrophobic pocket and specific variation at other amino-acid positions within the ATP-binding cavity. In particular, BbCDPK4 and PfCDPK1 are sensitive to a larger fraction of compounds than EtCDPK1 despite the presence of a threonine gatekeeper in all three CDPKs.
Single-phase calcium chlorosilicate and sodalite, two potential ceramic waste-forms for the immobilisation of CaCl2-based pyroprocessing wastes, have been fabricated at temperatures below the volatilisation point of CaCl2. Solid solutions doped with Sm3+ as an inactive analogue for trivalent actinides have been fabricated and characterised. XRD analysis shows both phases will successfully accommodate Sm3+, with the sodalite in particular remaining single-phase. Fabrication of Sm-doped calcium chlorosilicate in air results in the formation of SmOCl and Ca(Si2O5) secondary phases, however, calcination in an inert atmosphere is shown to successfully retard the formation of SmOCl allowing for higher levels of doping.
Hot Isostatic Pressing of Cs-exchanged IONSIV IE-911 samples is shown to produce a mixture of ceramic phases, the nature and mass fractions of these have been determined by Rietveld analysis of powder X-ray diffraction data. The main Cs phase that forms is Cs2TiNb6O18, after this reaches approximately 30% of the total crystalline content the remaining Cs is partitioned into Cs2ZrSi6O15. Durability tests using the PCT-B method for 7 days at 90 °C with deionised water lead to Cs leach rates of 0.032 and 0.038 g∙m−2∙day−1 for samples exchanged to 6 and 12 wt% Cs, respectively, indicating a durable wasteform is produced.
We report on in situ studies of the vibrational properties of ultra-thin Si layers grown by dc magnetron sputtering in ultrahigh vacuum on amorphous MgO and Ag buffer layers. The average thickness of the Si layers ranged from monolayer coverage up to 200 Å. The interference enhanced Raman scattering technique has been used to study changes in the phonon spectra of Si nanoparticles during the crystallization process. Marked size-dependencies in the phonon density of states of the Si quantum dots and the relaxation of the k-vector conservation condition with decrease in size of the Si nanoparticles have been detected. Electron energy loss spectra have been collected for amorphous and crystallized Si nanoparticles on SiO2 buffer layers and the difference in the onset of the electronic transitions have been found.
Good dispersion of oxide ceramics in organic solvents can be achieved using many different dispersants. Several types of dispersants, including fatty acids, coupling agents, polar aromatic compounds and polymers, are discussed to illustrate the important phenomena. Many new problems arise in actual slips during ceramics processing; these are briefly discussed.
The classical formation of metallic glasses by rapid quenching requires the suppression of the nucleation and growth of crystalline phases during cooling from the liquid alloy melt. More recently a variety of techniques have been described in the literature wherein amorphous metal alloys have been prepared by diffusion reactions under solid state conditions. These include hydrogen glass forming reactions, multilayer diffusion couples, and mechanical alloying.
Wet chemical and thermal synthetic methods are described which allow the preparation of a wide variety of multi-component amorphous metal alloy precursors. Subsequent heat-treatment of these precursor materials serves to transform them into a substantially amorphous metal alloy powder. In the parent process, at least one metal-bearing compound is disposed in a liquid medium then reduced so as to obtain an intimate molecular mixture of the elements of the amorphous metal alloy to be synthesized. Specific examples of typical reduction procedures and variations are included. The modification of the chemical reaction schemes with respect to the parent process will be addressed in terms of the variability of intermediate precursor mixtures that can be isolated. In all cases, the critical step for the production of the amorphous metal alloy is the synthesis of a homogeneous, intimate mixture in the precursor powder. The solid-state reaction which occurs to alloy this intimate mixture is discussed in terms of the relative free energy difference between the intimate mixture and the resultant amorphous alloy.
The formation of low temperature Au-Ge contacts to n-GaAs is a two-step process. In the first step, the metals segregate into Au and Ge rich regions and the intermixing of the Au and Ge with the Ga and As causes a reduction in the barrier height. The second step occurs after extended annealing, during which time Au and Ge continue to diffuse into the substrate. An orthorhombic Au-Ga phase is formed and it is likely that other Au-Ga or Ge-As phases are formed. The length of the extended anneal is dependent upon the atomic percent of Ge in the film, with the 10 at. % Ge taking 6 hr., the 27 at. % Ge taking 3 hr. and the 50 at. % Ge taking 9 hr. to become ohmic. The 75 at. % Ge sample doesn’t show ohmic behavior even after 33 hr. of annealing. The metal-semiconductor interface configuration appears abrupt, showing no protrusions into the GaAs substrate.