361 research outputs found

    The application of Raman and anti-stokes Raman spectroscopy for in-situ monitoring of structural changes in laser irradiated titanium dioxide materials.

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    The use of Raman and anti-stokes Raman spectroscopy to investigate the effect of exposure to high power laser radiation on the crystalline phases of TiO 2 has been investigated. Measurement of the changes, over several time integrals, in the Raman and anti-stokes Raman of TiO 2 spectra with exposure to laser radiation is reported. Raman and anti-stokes Raman provide detail on both the structure and the kinetic process of changes in crystalline phases in the titania material. The effect of laser exposure resulted in the generation of increasing amounts of the rutile crystalline phase from the anatase crystalline phase during exposure. The Raman spectra displayed bands at 144 cm -1 (A1g), 197 cm -1 (Eg), 398 cm -1 (B1g), 515 cm -1 (A1g), and 640 cm -1 (Eg) assigned to anatase which were replaced by bands at 143 cm -1 (B1g), 235 cm -1 (2 phonon process), 448 cm -1 (Eg) and 612 cm -1 (A1g) which were assigned to rutile. This indicated that laser irradiation of TiO 2 changes the crystalline phase from anatase to rutile. Raman and anti-stokes Raman are highly sensitive to the crystalline forms of TiO 2 and allow characterisation of the effect of laser irradiation upon TiO 2 . This technique would also be applicable as an in situ method for monitoring changes during the laser irradiation process

    In vitro optical quality measurements of three intraocular lens models having identical platform

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    Background: With recent advances in technology and introduction of new intraocular lens (IOL) models, surgeons today have the opportunity to choose from various optical designs, which can influence the postoperative quality of vision. In our laboratory study, we compared the optical quality of three different IOLs that use the identical platform and are produced by the same manufacturer. The study included two diffractive multifocal IOLs, a bifocal and a trifocal one, as well as a monofocal IOL. Methods: Three IOL models: monofocal CT ASPHINA 409 M, diffractive bifocal AT LISA 809 M, and diffractive trifocal AT LISA Tri 839MP (Carl Zeiss Meditec AG, Germany) were assessed for optical quality by measuring modulation transfer function (MTF) and Strehl Ratio (SR) values at pupil sizes of 3.0 and 4.5 mm on the OptiSphericŸ IOL PRO (Trioptics GmbH, Germany). The United States Air Force (USAF) Target images were also recorded to comfirm the optical performance qualitatively. Results: For far focus at 50 lp/mm and 3.0 mm pupil size, MTF value of the monofocal lens (MTF = 0.798) was 1.8-fold and 2.1-fold better than the bifocal (MTF = 0.446) and the trifocal (MTF = 0.382) IOLs, respectively. For near focus, bifocal IOL (MTF = 0.265) was 1.4-fold better than trifocal IOL (MTF = 0.187), while for intermediate focus, the trifocal IOL (MTF = 0.148) was 1.7-fold better than the bifocal IOL (MTF = 0.086). For the same pupil size, total sum of light loss amounted to 5.2% for the monofocal, 16.0% for the bifocal and 6.0% for the trifocal IOL. For a larger pupil, the amount of light loss increased significantly for the multifocal IOLs. Conclusions: The monofocal IOL performed the best for far, the bifocal IOL for near and the trifocal IOL for intermediate focus. While the monofocal IOL created the least amount of light loss for both pupil sizes, the trifocal IOL created less than half the amount of light loss than the bifocal IOL for small pupil. For large pupil, however, less light scatter was observed for the bifocal than the trifocal IOL

    The design, delivery and evaluation of ‘Human Perspectives VR’: An immersive educational programme designed to raise awareness of contributory factors for a traumatic childbirth experience and PTSD

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    Background A traumatic childbirth experience affects ~30% of women each year, with negative impacts on maternal, infant, and family wellbeing. Women classified as vulnerable or marginalised are those more likely to experience a psychologically traumatising birth. A key contributory factor for a traumatic childbirth experience is women’s relationships with maternity care providers. Aims To develop, design and evaluate an immersive educational programme for maternity care providers to raise awareness of traumatic childbirth experiences amongst vulnerable groups, and ultimately to improve women’s experiences of childbirth. Methods A critical pedagogical approach that utilised virtual reality (VR) underpinned the design and development of the educational programme. This involved: a) collecting vulnerable/disadvantaged women’s experiences of birth via interviews; b) analysing data collected to identify key hotspots for traumatic experiences within interpersonal patient – provider relationships to develop a script; c) filming the script with professional actors creating a first person perspective via VR technology; d) using existing literature to inform the theoretical and reflective aspects of the programme; e) conducting an evaluation of the education programme using pre-and post-evaluation questionnaires and a follow-up focus group. Findings Human Perspective VR was very well received. Participants considered the content to have enhanced their reflective practice and increased their knowledge base regarding contributory factors associated with a traumatic childbirth experience. A need for further work to implement learning into practice was highlighted. Conclusion While further research is needed to evaluate the impact of the programme, Human Perspective VR programme offers an innovative approach to reflective education and to enhance participants’ care practices

    M13-templated magnetic nanoparticles for targeted in vivo imaging of prostate cancer

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    Molecular imaging allows clinicians to visualize the progression of tumours and obtain relevant information for patient diagnosis and treatment1. Owing to their intrinsic optical, electrical and magnetic properties, nanoparticles are promising contrast agents for imaging dynamic molecular and cellular processes such as protein–protein interactions, enzyme activity or gene expression2. Until now, nanoparticles have been engineered with targeting ligands such as antibodies and peptides to improve tumour specificity and uptake. However, excessive loading of ligands can reduce the targeting capabilities of the ligand3, 4, 5 and reduce the ability of the nanoparticle to bind to a finite number of receptors on cells6. Increasing the number of nanoparticles delivered to cells by each targeting molecule would lead to higher signal-to-noise ratios and would improve image contrast. Here, we show that M13 filamentous bacteriophage can be used as a scaffold to display targeting ligands and multiple nanoparticles for magnetic resonance imaging of cancer cells and tumours in mice. Monodisperse iron oxide magnetic nanoparticles assemble along the M13 coat, and its distal end is engineered to display a peptide that targets SPARC glycoprotein, which is overexpressed in various cancers. Compared with nanoparticles that are directly functionalized with targeting peptides, our approach improves contrast because each SPARC-targeting molecule delivers a large number of nanoparticles into the cells. Moreover, the targeting ligand and nanoparticles could be easily exchanged for others, making this platform attractive for in vivo high-throughput screening and molecular detection.National Institutes of Health (U.S.) (NIH Center for Cancer Nanotechnology Excellence U54-CA151884)National Institutes of Health (U.S.) (NIH NCI RO1 CA137071

    Points of Connection: Using Wikidata for Art Information

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    Wikidata is a free, open, and multilingual knowledge base that serves as the structured data for Wikipedia and other Wikimedia projects. Staff at many libraries, archives, and museums have found that Wikidata provides an accessible method of making information about collections and resources available as linked open data, which in turn enables greater discoverability, new audiences, and innovative forms of research. This panel featured case studies from art institutions where Wikidata projects are underway. Many of the featured projects highlighted the use of Wikidata for identity management, such for artist names, both as an alternative to and alongside vocabularies traditionally used in art information. Panelists spoke to how their respective Wikidata projects support the interests of researchers and broader institutional efforts. Together, the presented projects demonstrated how Wikidata’s relatively low barrier to entry allows institutions to connect data that might otherwise be siloed in local repositories

    Stroke

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    Previous observational studies reported that a lower serum 25-hydroxyvitamin D [25(OH)D] concentration is associated with a higher burden of cerebral small vessel disease (cSVD). The causality of this association is uncertain, but it would be clinically important, given that 25(OH)D can be a target for intervention. We tried to examine the causal effect of 25(OH)D concentration on cSVD-related phenotypes using a Mendelian randomization approach. Genetic instruments for each serum 25(OH)D concentration and cSVD-related phenotypes (lacunar stroke, white matter hyperintensity, cerebral microbleeds, and perivascular spaces) were derived from large-scale genome-wide association studies. We performed 2-sample Mendelian randomization analyses with multiple post hoc sensitivity analyses. A bidirectional Mendelian randomization approach was also used to explore the possibility of reverse causation. We failed to find any significant causal effect of 25(OH)D concentration on cSVD-related phenotypes (odds ratio [95% CI], 1.00 [0.87-1.16], 1.01 [0.96-1.07], 1.06 [0.85-1.33], 1.00 [0.97-1.03], 1.02 [0.99-1.04], 1.01 [0.99-1.04] for lacunar stroke, white matter hyperintensity, cerebral microbleeds, and white matter, basal ganglia, hippocampal perivascular spaces, respectively). These results were reproduced in the sensitivity analyses accounting for genetic pleiotropy. Conversely, when we examined the effects of cSVD phenotypes on 25(OH)D concentration, cerebral microbleeds were negatively associated with 25(OH)D concentration (0.94 [0.92-0.96]). Given the adequate statistical power (>0.8) of the analyses, our findings suggest that the previously reported association between 25(OH)D concentration and cSVD phenotypes might not be causal and partly attributed to reverse causation

    Brain structural covariance networks in obsessive-compulsive disorder: a graph analysis from the ENIGMA Consortium.

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    Brain structural covariance networks reflect covariation in morphology of different brain areas and are thought to reflect common trajectories in brain development and maturation. Large-scale investigation of structural covariance networks in obsessive-compulsive disorder (OCD) may provide clues to the pathophysiology of this neurodevelopmental disorder. Using T1-weighted MRI scans acquired from 1616 individuals with OCD and 1463 healthy controls across 37 datasets participating in the ENIGMA-OCD Working Group, we calculated intra-individual brain structural covariance networks (using the bilaterally-averaged values of 33 cortical surface areas, 33 cortical thickness values, and six subcortical volumes), in which edge weights were proportional to the similarity between two brain morphological features in terms of deviation from healthy controls (i.e. z-score transformed). Global networks were characterized using measures of network segregation (clustering and modularity), network integration (global efficiency), and their balance (small-worldness), and their community membership was assessed. Hub profiling of regional networks was undertaken using measures of betweenness, closeness, and eigenvector centrality. Individually calculated network measures were integrated across the 37 datasets using a meta-analytical approach. These network measures were summated across the network density range of K = 0.10-0.25 per participant, and were integrated across the 37 datasets using a meta-analytical approach. Compared with healthy controls, at a global level, the structural covariance networks of OCD showed lower clustering (P < 0.0001), lower modularity (P < 0.0001), and lower small-worldness (P = 0.017). Detection of community membership emphasized lower network segregation in OCD compared to healthy controls. At the regional level, there were lower (rank-transformed) centrality values in OCD for volume of caudate nucleus and thalamus, and surface area of paracentral cortex, indicative of altered distribution of brain hubs. Centrality of cingulate and orbito-frontal as well as other brain areas was associated with OCD illness duration, suggesting greater involvement of these brain areas with illness chronicity. In summary, the findings of this study, the largest brain structural covariance study of OCD to date, point to a less segregated organization of structural covariance networks in OCD, and reorganization of brain hubs. The segregation findings suggest a possible signature of altered brain morphometry in OCD, while the hub findings point to OCD-related alterations in trajectories of brain development and maturation, particularly in cingulate and orbitofrontal regions

    Hospitalization and emergency department visits among seniors receiving homecare: a pilot study

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    BACKGROUND: Despite the recent growth in home health services, data on clinical outcomes and acute health care utilization among older adults receiving homecare services are sparse. Obtaining such data is particularly relevant in Ontario where an increasing number of frail seniors receiving homecare are awaiting placement in long-term care facilities. In order to determine the feasibility of a large-scale study, we conducted a pilot study to assess utilization of acute health care services among seniors receiving homecare to determine associated clinical outcomes. METHODS: This prospective cohort study followed forty-seven seniors admitted to homecare by two homecare agencies in Hamilton, Ontario over a 12-month period. Demographic information and medical history were collected at baseline, and patients were followed until either termination of homecare services, death, or end of study. The primary outcome was hospitalization. Secondary outcomes included emergency department visits that did not result in hospitalization and death. Rates of hospitalization and emergency department visits without admission were calculated, and univariate analyses were performed to test for potential risk factors. Survival curves for accumulative rates of hospitalization and emergency department visits were created. RESULTS: 312 seniors were eligible for the study, of which 123 (39%) agreed to participate initially. After communicating with the research nurse, of the 123 who agreed to participate initially, 47 (38%) were enrolled in the study. Eleven seniors were hospitalized during 3,660 days of follow-up for a rate of 3.0 incident hospitalizations per 1,000 homecare-days. Eleven seniors had emergency department visits that did not result in hospitalization, for a rate of 3.3 incident emergency department visits per 1,000 homecare-days. There were no factors significantly associated with hospitalization or emergency department visits when adjustment was made for multiple comparisons. CONCLUSION: The incidence of hospitalization and visits to the emergency department among seniors receiving homecare services is high. Getting satisfactory levels of enrolment will be a major challenge for larger prospective studies
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