Radiation tolerance of nanocrystalline ceramics: insights from Yttria Stabilized Zirconia.

Materials for applications in hostile environments, such as nuclear reactors or radioactive waste immobilization, require extremely high resistance to radiation damage, such as resistance to amorphization or volume swelling. Nanocrystalline materials have been reported to present exceptionally high radiation-tolerance to amorphization. In principle, grain boundaries that are prevalent in nanomaterials could act as sinks for point-defects, enhancing defect recombination. In this paper we present evidence for this mechanism in nanograined Yttria Stabilized Zirconia (YSZ), associated with the observation that the concentration of defects after irradiation using heavy ions (Kr(+), 400 keV) is inversely proportional to the grain size. HAADF images suggest the short migration distances in nanograined YSZ allow radiation induced interstitials to reach the grain boundaries on the irradiation time scale, leaving behind only vacancy clusters distributed within the grain. Because of the relatively low temperature of the irradiations and the fact that interstitials diffuse thermally more slowly than vacancies, this result indicates that the interstitials must reach the boundaries directly in the collision cascade, consistent with previous simulation results. Concomitant radiation-induced grain growth was observed which, as a consequence of the non-uniform implantation, caused cracking of the nano-samples induced by local stresses at the irradiated/non-irradiated interfaces

Protection against discrimination in national dementia guideline recommendations: A systematic review

BACKGROUND: National dementia guidelines provide recommendations about the most effective approaches to diagnosis and interventions. Guidelines can improve care, but some groups such as people with minority characteristics may be disadvantaged if recommended approaches are the same for everyone. It is not known if dementia guidelines address specific needs related to patient characteristics. The objectives of this review are to identify which countries have national guidelines for dementia and synthesise recommendations relating to protected characteristics, as defined in the UK Equality Act 2010: age, disability, gender identity, marriage and civil partnership, pregnancy and maternity, race, religion or belief, sex, and sexual orientation. METHODS AND FINDINGS: We searched CINAHL, PsycINFO, and Medline databases and the Guideline International Network library from inception to March 4, 2020, for dementia guidelines in any language. We also searched, between April and September 2020, Google and the national health websites of all 196 countries in English and in each country’s official languages. To be included, guidelines had to provide recommendations about dementia, which were expected to be followed by healthcare workers and be approved at a national policy level. We rated quality according to the iCAHE guideline quality checklist. We provide a narrative synthesis of recommendations identified for each protected characteristic, prioritising those from higher-quality guidelines. Forty-six guidelines from 44 countries met our criteria, of which 18 were rated as higher quality. Most guidelines (39/46; 85%) made at least one reference to protected characteristics, and we identified recommendations relating to age, disability, race (or culture, ethnicity, or language), religion, sex, and sexual orientation. Age was the most frequently referenced characteristic (31/46; 67%) followed by race (or culture, ethnicity, or language; 25/46; 54%). Recommendations included specialist investigation and support for younger people affected by dementia and consideration of culture when assessing whether someone had dementia and providing person-centred care. Guidelines recommended considering religion when providing person-centred and end-of-life care. For disability, it was recommended that healthcare workers consider intellectual disability and sensory impairment when assessing for dementia. Most recommendations related to sex recommended not using sex hormones to treat cognitive impairment in men and women. One guideline made one recommendation related to sexual orientation. The main limitation of this study is that we only included national guidelines applicable to a whole country meaning guidelines from countries with differing healthcare systems within the country may have been excluded. CONCLUSIONS: National guidelines for dementia vary in their consideration of protected characteristics. We found that around a fifth of the world’s countries have guidelines for dementia. We have identified areas of good practice that can be considered for future guidelines and suggest that all guidelines provide specific evidence-based recommendations for minority groups with examples of how to implement them. This will promote equity in the care of people affected by dementia and help to ensure that people with protected characteristics also have high-quality clinical services

A cross-sectional study on caregivers' perspective of the quality of life and adherence of paediatric HIV patients to highly active antiretroviral therapy.

BACKGROUND:Poor compliance to highly active antiretroviral therapy (HAART) can result in the poor quality of life in children living with Human immunodeficiency virus/Acquired immunodeficiency syndrome (HIV/AIDS) because of low plasma drug concentration and the possibility of drug resistance. This study evaluates the response of caregivers for determination of adherence and the four quality of life domains in children (aged 14 years and under) on HAART. METHODS:We conducted a cross-sectional study of 188 children, each accompanied by their caregivers at Ola During Children's Hospital and Makeni Government Hospital between September and November 2016. Adherence to HAART and Quality of life was assessed using the WHO Quality of life summary questionnaire (WHOQOL-BREF). We obtained ethical approval from the Sierra Leone Ethics and Scientific Review Committee. RESULTS:The study revealed 5.9% adherence amongst paediatric patients, and a strong association of adherent patients(p = 0.019*) to the physical health domain (mean = 64.61 SD = 8.1). Caregiver HIV status showed a strong association with the physical (mean = 58.3, SD = 11.7 and p = 0.024*), and psychological health domains (mean = 68.2, SD = 14.7 and p = 0.001). Caregiver type (mother/father/sibling) accompanying child to hospital also showed strong associated with the physical (mean = 58.0, SD = 10.6, p <  0.001), psychological (mean 68.2 SD = 14.81 p <  0.001) and environmental health domains (mean = 59.7, SD = 13.47, p <  0.001). Further regression analysis showed a strong association with physical health domain for HIV positive caregivers (p = 0.014) and adherent paediatric patients (p = 0.005). Nuclear family also showed a strong association with psychological (p <  0.001) and environmental (p = 0.001) health domains. CONCLUSION:This study showed a strong association between the quality of life domains and the involvement of nuclear family caregiver, HIV-positive caregiver and adherence to HAART. Our study suggests that the involvement of any member of the nuclear family, HIV positive parents and patient adherence to therapy can improve the quality of life of paediatric HIV/AIDS patients on highly active antiretroviral therapy in the two hospitals

Delayed onset of changes in soma action potential genesis in nociceptive A-beta DRG neurons in vivo in a rat model of osteoarthritis

<p>Abstract</p> <p>Background</p> <p>Clinical data on osteoarthritis (OA) suggest widespread changes in sensory function that vary during the progression of OA. In previous studies on a surgically-induced animal model of OA we have observed that changes in structure and gene expression follow a variable trajectory over the initial days and weeks. To investigate mechanisms underlying changes in sensory function in this model, the present electrophysiological study compared properties of primary sensory nociceptive neurons at one and two months after model induction with properties in naïve control animals. Pilot data indicated no difference in C- or Aδ-fiber associated neurons and therefore the focus is on Aβ-fiber nociceptive neurons.</p> <p>Results</p> <p>At one month after unilateral derangement of the knee by cutting the anterior cruciate ligament and removing the medial meniscus, the only changes observed in Aβ-fiber dorsal root ganglion (DRG) neurons were in nociceptor-like unresponsive neurons bearing a hump on the repolarization phase; these changes consisted of longer half width, reflecting slowed dynamics of AP genesis, a depolarized Vm and an increased AP amplitude. At two months, changes observed were in Aβ-fiber high threshold mechanoreceptors, which exhibited shorter AP duration at base and half width, shorter rise time and fall time, and faster maximum rising rate/maximum falling rate, reflecting accelerated dynamics of AP genesis.</p> <p>Conclusion</p> <p>These data indicate that Aβ nociceptive neurons undergo significant changes that vary in time and occur later than changes in structure and in nociceptive scores in this surgically induced OA model. Thus, if changes in Aβ-fiber nociceptive neurons in this model reflect a role in OA pain, they may relate to mechanisms underlying pain associated with advanced OA.</p

Can HRCT be used as a marker of airway remodelling in children with difficult asthma?

BACKGROUND: Whole airway wall thickening on high resolution computed tomography (HRCT) is reported to parallel thickening of the bronchial epithelial reticular basement membrane (RBM) in adult asthmatics. A similar relationship in children with difficult asthma (DA), in whom RBM thickening is a known feature, may allow the use of HRCT as a non-invasive marker of airway remodelling. We evaluated this relationship in children with DA. METHODS: 27 children (median age 10.5 [range 4.1-16.7] years) with DA, underwent endobronchial biopsy from the right lower lobe and HRCT less than 4 months apart. HRCTs were assessed for bronchial wall thickening (BWT) of the right lower lobe using semi-quantitative and quantitative scoring techniques. The semi-quantitative score (grade 0-4) was an overall assessment of BWT of all clearly identifiable airways in HRCT scans. The quantitative score (BWT %; defined as [airway outer diameter - airway lumen diameter]/airway outer diameter x100) was the average score of all airways visible and calculated using electronic endpoint callipers. RBM thickness in endobronchial biopsies was measured using image analysis. 23/27 subjects performed spirometry and the relationships between RBM thickness and BWT with airflow obstruction evaluated. RESULTS: Median RBM thickness in endobronchial biopsies was 6.7(range 4.6-10.0) microm. Median qualitative score for BWT of the right lower lobe was 1(range 0-1.5) and quantitative score was 54.3 (range 48.2-65.6)%. There was no relationship between RBM thickness and BWT in the right lower lobe using either scoring technique. No relationship was found between FEV1 and BWT or RBM thickness. CONCLUSION: Although a relationship between RBM thickness and BWT on HRCT has been found in adults with asthma, this relationship does not appear to hold true in children with D

Mechanical Properties of End-crosslinked Entangled Polymer Networks using Sliplink Brownian Dynamics Simulations

The mechanical properties of a polymeric network containing both crosslinks and sliplinks (entanglements) are studied using a multi-chain Brownian dynamics simulation. We coarse-grain at the level of chain segments connecting consecutive nodes (cross- or sliplinks), with particular attention to the Gaussian statistics of the network. Affine displacement of nodes is not imposed: their displacement as well as sliding of monomers through sliplinks is governed by force balances. The simulation results of stress in uniaxial extension and the full stress tensor in simple shear including the (non-zero) second normal stress difference are presented for monodisperse chains with up to 18 entanglements between two crosslinks. The cases of two different force laws of the subchains (Gaussian chains and chains with finite extensibility) for two different numbers of monomers in a subchain (no = 50 and no = 100) are examined. It is shown that the additivity assumption of slip- and crosslink contribution holds for sufficiently long chains with two or more entanglements, and that it can be used to construct the strain response of a network of infinitely long chains. An important consequence is that the contribution of sliplinks to the small-strain shear modulus is about &#8532; of the contribution of a crosslink

Measurement of Residual Stresses Around a Circular Patch Weld Using Barkhausen Noise

Welding is a common means of joining and repairing steel structures. In the case of steel tanks, circular patch welds are often used for repairing the structure after removal of a defective area. Unfortunately, the welding process also produces residual stresses which, if not relieved, can impair the integrity of the structure. Measurement of residual stresses produced by welding is needed, for example, to verify the effectiveness of a stress relief heat treatment which is typically used to remove weld-induced stresses

Negative and positive selection of antigen-specific cytotoxic T lymphocytes affected by the α3 domain of MHC I molecules

THE α1 and α2 domains of major histocompatibility complex (MHC) class I molecules function in the binding and presentation of foreign peptides to the T-cell antigen receptor and control both negative and positive selection of the T-cell repertoire. Although the α3 domain of class I is not involved in peptide binding, it does interact with the T-cell accessory molecule, CDS. CDS is important in the selection of T cells as anti-CDS antibody injected into perinatal mice interfers with this process. We previously used a hybrid class I molecule with the α1/α2 domains from L^d and the α3 domain from Q7^b and showed that this molecule binds an L^d-restricted peptide but does not interact with CD8-dependent cytotoxic T lymphocytes. Expression of this molecule in transgenic mice fails to negatively select a subpopulation of anti-L^d cytotoxic T lymphocytes. In addition, positive selection of virus-specific L^d-restricted cytotoxic T lymphocytes does not occur. We conclude that besides the α1/α2 domains of class I, the α3 domain plays an important part in both positive and negative selection of antigen-specific cells

Star Formation Rate Indicators in Wide-Field Infrared Survey Preliminary Release

With the goal of investigating the degree to which theMIR luminosity in theWidefield Infrared Survey Explorer (WISE) traces the SFR, we analyze 3.4, 4.6, 12 and 22 {\mu}m data in a sample of {\guillemotright} 140,000 star-forming galaxies or star-forming regions covering a wide range in metallicity 7.66 < 12 + log(O/H) < 9.46, with redshift z < 0.4. These star-forming galaxies or star-forming regions are selected by matching the WISE Preliminary Release Catalog with the star-forming galaxy Catalog in SDSS DR8 provided by JHU/MPA 1.We study the relationship between the luminosity at 3.4, 4.6, 12 and 22 {\mu}m from WISE and H\alpha luminosity in SDSS DR8. From these comparisons, we derive reference SFR indicators for use in our analysis. Linear correlations between SFR and the 3.4, 4.6, 12 and 22 {\mu}m luminosity are found, and calibrations of SFRs based on L(3.4), L(4.6), L(12) and L(22) are proposed. The calibrations hold for galaxies with verified spectral observations. The dispersion in the relation between 3.4, 4.6, 12 and 22 {\mu}m luminosity and SFR relates to the galaxy's properties, such as 4000 {\deg}A break and galaxy color.Comment: 10 pages, 3 figure