The effects of noise in cardiac diffusion tensor imaging and the benefits of averaging complex data

There is growing interest in cardiac diffusion tensor imaging (cDTI), but, unlike other diffusion MRI applications, there has been little investigation of the effects of noise on the parameters typically derived. One method of mitigating noise floor effects when there are multiple image averages, as in cDTI, is to average the complex rather than the magnitude data, but the phase contains contributions from bulk motion, which must be removed first. The effects of noise on the mean diffusivity (MD), fractional anisotropy (FA), helical angle (HA) and absolute secondary eigenvector angle (E2A) were simulated with various diffusion weightings (b values). The effect of averaging complex versus magnitude images was investigated. In vivo cDTI was performed in 10 healthy subjects with b = 500, 1000, 1500 and 2000 s/mm². A technique for removing the motion‐induced component of the image phase present in vivo was implemented by subtracting a low‐resolution copy of the phase from the original images before averaging the complex images. MD, FA, E2A and the transmural gradient in HA were compared for un‐averaged, magnitude‐ and complex‐averaged reconstructions. Simulations demonstrated an over‐estimation of FA and MD at low b values and an under‐estimation at high b values. The transition is relatively signal‐to‐noise ratio (SNR) independent and occurs at a higher b value for FA (b = 1000–1250 s/mm²) than MD (b ≈ 250 s/mm²). E2A is under‐estimated at low and high b values with a transition at b ≈ 1000 s/mm², whereas the bias in HA is comparatively small. The under‐estimation of FA and MD at high b values is caused by noise floor effects, which can be mitigated by averaging the complex data. Understanding the parameters of interest and the effects of noise informs the selection of the optimal b values. When complex data are available, they should be used to maximise the benefit from the acquisition of multiple averages. The combination of complex data is also a valuable step towards segmented acquisitions. Copyright © 2016 John Wiley & Sons, Ltd.     

Evidence-Based Practice Implementation Within a Theory of Planned Behavior Framework

Although significant progress has been made in the identification of youth evidence-based practices, the adoption of these interventions into community-based mental health care remains limited. Dissemination and implementation (DI) research has the potential to bridge this science-practice gap in clinical psychology. The theory of planned behavior (TPB) offers a useful conceptualization of individual behavior change including behavioral intention as defined by attitudes, subjective norms, and perceived behavioral control. To facilitate application of this model to DI efforts, the current study explores perspectives about using evidence-based practice from stakeholders in the field of youth mental health (including clinical supervisors, case managers, administrators at the departments of health and education, and direct service providers in clinic-based, school-based, and intensive in-home settings) within the TPB framework. A set of instrument items was created from this rich qualitative data using a rigorous mixed-method content validation approach. Instrument items are provided for future use in DI research.     

Magnetic-based multi-layer microparticles for endothelial progenitor cell isolation,enrichment, and detachment

Although endothelial progenitor cells (EPCs) are useful in many applications including cell-based therapies, their use is still limited due to issues associated with cell culture techniques like a low isolation efficiency, use of harmful proteolytic enzymes in cell cultures, and difficulty in ex vivo expansion. Here, we report a tool to simultaneously isolate, enrich, and detach EPCs without the use of harmful chemicals. In particular, we developed magnetic-based multi-layer microparticles (MLMPs) that (1) magnetically isolate EPCs via anti-CD34 antibodies to avoid the use of Ficoll and harsh shear forces; (2) provide a 3D surface for cell attachment and growth; (3) produce sequential releases of growth factors (GFs) to enrich ex vivo expansion of cells; and (4) detach cells without using trypsin. MLMPs were successful in isolating EPCs from a cell suspension and provided a sequential release of GFs for EPC proliferation and differentiation. The cell enrichment profiles indicated steady cell growth on MLMPs in comparison to commercial Cytodex3 microbeads. Further, the cells were detached from MLMPs by lowering the temperature below 32 °C. Results indicate that the MLMPs have potential to be an effective tool towards efficient cell isolation, fast expansion, and non-chemical detachment.     

Prevalence of Thoracic Aortic Aneurysms in Patients with Degenerative Abdominal Aortic Aneurysms: Results from the Prospective ACTA Study

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Phlebotomine fauna in the Ponta Porã city: epidemiological importance in border line between Brazil and Paraguay

ObjectiveTo identify the urban phlebotomine sandfly fauna in Ponta Porã, Mato Grosso do Sul State, Brazil.MethodsThe captures were undertaken from April 2009 to March 2010 with CDC light traps in 14 ecotopes (intra and peridomicile) in different areas of the city, Shannon traps being used in areas with abundant vegetation.ResultsA total of 707 specimens were captured with CDC light traps (565 males and 142 females) and 155 specimens (112 males and 43 females) with Shannon traps, a total of 862 phlebotomines. The specimens captured belonged to eight species: Lutzomyia longipalpis (Lutz & Neiva, 1912), Evandromyia cortelezzii (Brethes, 1923), Sciopemyia sordelli (Shannon & Del Ponte, 1927), Pintomyia pessoai (Coutinho & Barretto, 1940); Pintomyia monticola (Costa Lima, 1932); Brumptomyia brumpti (Larousse, 1920); Nyssomyia whitmani (Antunes & Coutinho, 1939) and Psathyromyia shannoni (Dyar, 1929). Lutzomyia longipalpis, the main vector of Leishmania (Leishmania) chagasi, was the species most frequently captured (97.03%) and also the most abundant according to the standardized abundance index (SAI)=0.86.ConclusionsThe highest species richness was captured, with CDC light traps, inside the domiciles and the species diversity and evenness in the peridomicile, clearly indicating a preference for anthropic environments.