821 research outputs found

    Overview of field-testing of the revised, draft South African Paediatric Food-Based Dietary Guidelines amongst mothers/caregivers of children aged 0–5 years in the Western Cape and Mpumalanga, South Africa

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    Background: This paper provides an overview of a series of studies undertaken to assess the appropriateness and understanding of the revised, draft South African Paediatric Food-Based Dietary Guidelines (SA-PFBDGs) amongst mothers/ caregivers of children aged 0–5 years. Previous exposure to guidelines with similar messages, barriers and enablers to following the guidelines were also assessed. Design: Qualitative methods were used to collect data from 38 focus-group discussions (isiXhosa = 11, Afrikaans = 11, English =10 and siSwati = 6) resulting in 268 participants. Setting: Breede Valley sub-district (Worcester), Stellenbosch Municipality (Stellenbosch, Pniel and Franschhoek) and Northern Metropole (Atlantis, Witsand, Du Noon and Blouberg), City of Cape Town, Western Cape province, as well as Ehlanzeni District (Kabokweni) in Mpumalanga province. Subjects: Mothers/caregivers older than 18 years who provided informed consent to participate. Results: The majority of participants had previous exposure to guidelines with similar messages to the SA-PFBDGs. Information sources included nurses, local clinics, family, friends and media. Possible barriers to following the guidelines included limited physical and financial access to resources; cultural/family practices, poor social support and time constraints. Outdated information, misconceptions, inconsistent messages and contrasting beliefs were evident. The vocabulary of some messages was not well understood. Education on infant and young child feeding and visual portrayal of the guidelines could aid understanding. Conclusion: A degree of rewording should be considered for improved understanding of the revised, draft SA-PFBDGs. Once adopted, the guidelines can be used to educate various stakeholders, including parents, caregivers, healthcare providers and educators, on the correct nutritional advice for children aged 0–5 years ensuring the healthy growth and development of young children in South Africa

    Проектирование активного шнекоротора для робота-толкателя кормов на животноводческой ферме

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    Целю выпусконой работы является проектирование активного шнекоротора для роботатолкателя кормов на животноводческой ферме, написание программы управления. В работе приведена характеристика роботовтолкателей и их сравнение, представлена программа управления агрегатом, приведены необходимые расчеты для создания траектории движения, выявлены опасные и вредные факторы, мероприятия по их ликвидации, а также техника безопасности.The goal of this work is to design an active screw rotor for a feed pusher on a livestock farm, and write a control program. The work describes the characteristics of robotic pushers and their comparison, presents the unit control program, provides the necessary calculations to create a trajectory of movement, identifies dangerous and harmful factors, measures to eliminate them, as well as safety

    Motion and twisting of magnetic particles ingested by alveolar macrophages in the human lung: effect of smoking and disease

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    BACKGROUND: Magnetic microparticles being ingested by alveolar macrophages can be used as a monitor for intracellular phagosome motions and cytoskeletal mechanical properties. These studies can be performed in the human lung after voluntary inhalation. The influence of cigarette smoking and lung diseases on cytoskeleton dependent functions was studied. METHODS: Spherical 1.3 μm diameter ferrimagnetic iron oxide particles were inhaled by 17 healthy volunteers (40 – 65 years), 15 patients with sarcoidosis (SAR), 12 patients with idiopathic pulmonary fibrosis (IPF), and 18 patients with chronic obstructive bronchitis (COB). The retained particles were magnetized and aligned in an external 100 mT magnetic field. All magnetized particles induce a weak magnetic field of the lung, which was detected by a sensitive SQUID (superconducting quantum interference device) sensor. Cytoskeletal reorganizations within macrophages and intracellular transport cause stochastic magnetic dipole rotations, which are reflected in a decay of the magnetic lung field, called relaxation. Directed phagosome motion was induced in a weak magnetic twisting field. The resistance of the cytoplasm to particle twisting was characterized by the viscosity and the stiffness (ratio between stress to strain) of the cytoskeleton. RESULTS: One week after particle inhalation and later macrophage motility (relaxation) and cytoskeletal stiffness was not influenced by cigarette smoking, neither in healthy subjects, nor in the patients. Patients with IPF showed in tendency a faster relaxation (p = 0.06). Particle twisting revealed a non-Newtonian viscosity with a pure viscous and a viscoelastic compartment. The viscous shear was dominant, and only 27% of the shear recoiled and reflected viscoelastic properties. In patients with IPF, the stiffness was reduced by 60% (p < 0.02). An analysis of the shear rate and stress dependence of particle twisting allows correlating the rheological compartments to cytoskeletal subunits, in which microtubules mediate the pure viscous (non-recoverable) shear and microfilaments mediate the viscoelastic (recoverable) behavior. The missing correlation between relaxation and particle twisting shows that both stochastic and directed phagosome motion reflect different cytoskeletal mechanisms. CONCLUSION: Faster relaxation and a soft cytoskeleton in patients with IPF indicate alterations in cytoskeleton dependent functions of alveolar macrophages, which may cause dysfunction's in the alveolar defense, like a slower migration, a retarded phagocytosis, a disturbed phagosome lysosome fusion and an impaired clearance

    Cubosomes from hierarchical self-assembly of poly(ionic liquid) block copolymers

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    Cubosomes are micro- and nanoparticles with a bicontinuous cubic two-phase structure, reported for the self-assembly of low molecular weight surfactants, for example, lipids, but rarely formed by polymers. These objects are characterized by a maximum continuous interface and high interface to volume ratio, which makes them promising candidates for efficient adsorbents and host-guest applications. Here we demonstrate self-assembly to nanoscale cuboidal particles with a bicontinuous cubic structure by amphiphilic poly(ionic liquid) diblock copolymers, poly(acrylic acid)-block-poly(4-vinylbenzyl)-3-butyl imidazolium bis(trifluoromethylsulfonyl)imide, in a mixture of tetrahydrofuran and water under optimized conditions. Structure determining parameters include polymer composition and concentration, temperature, and the variation of the solvent mixture. The formation of the cubosomes can be explained by the hierarchical interactions of the constituent components. The lattice structure of the block copolymers can be transferred to the shape of the particle as it is common for atomic and molecular faceted crystals

    Mechanical properties of freely suspended atomically thin dielectric layers of mica

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    We have studied the elastic deformation of freely suspended atomically thin sheets of muscovite mica, a widely used electrical insulator in its bulk form. Using an atomic force microscope, we carried out bending test experiments to determine the Young's modulus and the initial pre-tension of mica nanosheets with thicknesses ranging from 14 layers down to just one bilayer. We found that their Young's modulus is high (190 GPa), in agreement with the bulk value, which indicates that the exfoliation procedure employed to fabricate these nanolayers does not introduce a noticeable amount of defects. Additionally, ultrathin mica shows low pre-strain and can withstand reversible deformations up to tens of nanometers without breaking. The low pre-tension and high Young's modulus and breaking force found in these ultrathin mica layers demonstrates their prospective use as a complement for graphene in applications requiring flexible insulating materials or as reinforcement in nanocomposites.Comment: 9 pages, 5 figures, selected as cover of Nano Research, Volume 5, Number 8 (2012

    Application of optical diagnostics to the quantification of soot in n-alkane flames under diesel conditions

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    The present work pursues a twofold objective. On the one hand, the effect of fuel properties on soot formation has been analysed, under different engine operating conditions. On the other hand, sensitivity and performance of the three optical techniques has been evaluated, identifying their main advantages and drawbacks in the framework of the current study. LEM has been considered as the reference technique, as the measurement principle can be implemented without important limitations associated to the other two. Results highlight that larger molecules produce more soot than the smaller ones, with both reactivity and soot formation changing with the proportion of the heavier fraction. Despite describing similar trends, LEM and 2C do not provide the same KL values, with the pyrometry reaching some sort of saturation when increasing flame soot. A detailed analysis confirms that 2-Colar measurements are strongly biased by soot and temperature distribution inside the flame. Nevertheless, it could still be a good option for low sooting conditions. On the other hand, an attempt to calibrate LII signal by means of LEM measurements has been reported. This approach should make it possible to obtain additional information on the soot spatial distribution. However, inconsistencies have been identified which stem from the inherent limitations of LII technique in highly sooting conditions. (c) 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved.Authors wold like to acknowledge that part of this work has been funded by the Spanish Ministry of Science and Technology through project TRA2011-26359 and grant BES-2012-059721. Some other parts of this works were financially supported by "COMET K2 - Competence Centres for Excellent Technologies Programme" (project B03T02). In addition, the authors acknowledge that some equipment used in this work has been partially supported by FEDER project funds (FEDER-ICTS-2012-06)", framed in the operational program of unique scientific and technical infrastructure of the Ministry of Science and Innovation of Spain.Pastor Soriano, JV.; García Oliver, JM.; García Martínez, A.; Micó Reche, C.; Möller, S. (2016). Application of optical diagnostics to the quantification of soot in n-alkane flames under diesel conditions. Combustion and Flame. 164:212-223. https://doi.org/10.1016/j.combustflame.2015.11.018S21222316

    Downregulation of miR-92a Is Associated with Aggressive Breast Cancer Features and Increased Tumour Macrophage Infiltration

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    BACKGROUND: MicroRNAs are small non-coding RNAs involved in the regulation of gene expression on a posttranscriptional level. These regulatory RNAs have been implicated in numerous cellular processes and are further deregulated in different cancer types, including breast cancer. MiR-92a is part of the miR-17∼92 cluster, which was first reported to be linked to tumourigenesis. However, little is known about the expression of miR-92a in breast cancer and potential associations to tumour properties. The expression of miR-92a was therefore characterized in 144 invasive breast cancer samples using in situ hybridization and related to clinico-pathological data as well as to selected key properties of the tumour stroma, including the presence of macrophages (CD68) and cancer activated fibroblasts (alpha-SMA). METHODOLOGY/PRINCIPAL FINDINGS: To measure miR-92a levels, an in situ hybridisation protocol was developed and validated using cell lines and miR-92a inhibitors. The expression in the tumour samples was objectively evaluated using digital image analysis program subtracting background activities. We found that the miR-92a expression varied between tumours and was inversely correlated to tumour grade (r = -0.276, p = 0.003) and recurrence-free survival (p = 0.008) and provided independent prognostic information in multivariate Cox analysis (HR: 0.375, CI: 0.145-0.972, p = 0.043). MiR-92a was moreover inversely correlated to the number of infiltrating macrophages in the tumour stroma (r = -0.357, p<0.001), and downregulation of miR-92a promoted cell migration (p<0.01). CONCLUSIONS/SIGNIFICANCE: This study demonstrates that downregulation of miR-92a in breast cancer is linked to key epithelial and stromal properties as well as clinical outcome

    Curcumin: novel treatment in neonatal hypoxic-ischaemic brain injury

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    Hypoxic-ischaemic encephalopathy (HIE) is a major cause of mortality and morbidity in neonates, with an estimated global incidence of 3/1000 live births. HIE brain damage is associated with an inflammatory response and oxidative stress, resulting in the activation of cell death pathways. At present, therapeutic hypothermia is the only clinically approved treatment available for HIE. This approach, however, is only partially effective. There is therefore an unmet clinical need for the development of novel therapeutic interventions for the treatment of HIE. Curcumin is an antioxidant reactive oxygen species scavenger, with reported anti-tumour and anti-inflammatory activity. Curcumin has been shown to attenuate mitochondrial dysfunction, stabilise the cell membrane, stimulate proliferation, and reduce injury severity in adult models of spinal cord injury, cancer, and cardiovascular disease. The role of curcumin in neonatal HIE has not been widely studied due to its low bioavailability and limited aqueous solubility. The aim of this study was to investigate the effect of curcumin treatment in neonatal HIE, including time of administration and dose-dependent effects. Our results indicate that curcumin administration prior to HIE in neonatal mice elevated cell and tissue loss, as well as glial activation compared to HI alone. However, immediate post-treatment with curcumin was significantly neuroprotective, reducing grey and white matter tissue loss, TUNEL+ cell death, microglia activation, reactive astrogliosis and iNOS oxidative stress when compared to vehicle-treated littermates. This effect was dose-dependent, with 200µg/g body weight as the optimal dose-regimen, and was maintained when curcumin treatment was delayed by 60min or 120min post-HI. Cell proliferation measurements showed no changes between curcumin and HI alone, suggesting that the protective effects of curcumin on the neonatal brain following HI are most likely due to curcumin’s anti-inflammatory and antioxidant properties, as seen in the reduced glial and iNOS activity. In conclusion, this study suggests curcumin as a potent neuroprotective agent with potential for the treatment of HIE. The delayed application of curcumin further increases its clinical relevance
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