198 research outputs found
The Field of Allergy
A review based on a dissertation read before the Society on 10th December, 1965.This article concentrates on (i) the immunological basis, (ii) pathophysiological mechanisms, and (iii) control (theoretical and practical) of the immediate-type allergy.Antigen-antibody reactions constitute an important group of defences, facilitating phagocytosis and blocking the toxic effects of parasitic poisons. The reaction confers ‘immunity’. The combination of antigen and antibody is, however, not always beneficial. Pathological reactions as severe or more severe than the affect of the antigen alone arc sometimes noticed. Hypersensitivity or allergic reactions form major examples of such conditions. Allergy or hypersensitivity may be defined as a state in which the animal reacts in an excessive way to the introduction of an antigen or a hapten even though the antigen or hapten may be innocuous. Not all instances of hypersensitivity enjoy the identification of the exciting antigens, the mediating antibodies and the mechanisms of tissue damage
Transparent ferromagnetic and semiconducting behavior in Fe-Dy-Tb based amorphous oxide films
We report a class of amorphous thin film material comprising of transition (Fe) and Lanthanide metals (Dy and Tb) that show unique combination of functional properties. Films were deposited with different atomic weight ratio (R) of Fe to Lanthanide (Dy + Tb) using electron beam co-evaporation at room temperature. The films were found to be amorphous, with grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy studies indicating that the films were largely oxidized with a majority of the metal being in higher oxidation states. Films with R = 0.6 were semiconducting with visible light transmission due to a direct optical band-gap (2.49 eV), had low resistivity and sheet resistance (7.15 × 10−4 Ω-cm and ~200 Ω/sq respectively), and showed room temperature ferromagnetism. A metal to semiconductor transition with composition (for R \u3c 11.9) also correlated well with the absence of any metallic Fe0oxidation state in the R = 0.6 case as well as a significantly higher fraction of oxidized Dy. The combination of amorphous microstructure and room temperature electronic and magnetic properties could lead to the use of the material in multiple applications, including as a transparent conductor, active material in thin film transistors for display devices, and in spin-dependent electronics
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Highly efficient transfection of human induced pluripotent stem cells using magnetic nanoparticles.
PurposeThe delivery of transgenes into human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (hiPSC-CMs) represents an important tool in cardiac regeneration with potential for clinical applications. Gene transfection is more difficult, however, for hiPSCs and hiPSC-CMs than for somatic cells. Despite improvements in transfection and transduction, the efficiency, cytotoxicity, safety, and cost of these methods remain unsatisfactory. The objective of this study is to examine gene transfection in hiPSCs and hiPSC-CMs using magnetic nanoparticles (NPs).MethodsMagnetic NPs are unique transfection reagents that form complexes with nucleic acids by ionic interaction. The particles, loaded with nucleic acids, can be guided by a magnetic field to allow their concentration onto the surface of the cell membrane. Subsequent uptake of the loaded particles by the cells allows for high efficiency transfection of the cells with nucleic acids. We developed a new method using magnetic NPs to transfect hiPSCs and hiPSC-CMs. HiPSCs and hiPSC-CMs were cultured and analyzed using confocal microscopy, flow cytometry, and patch clamp recordings to quantify the transfection efficiency and cellular function.ResultsWe compared the transfection efficiency of hiPSCs with that of human embryonic kidney (HEK 293) cells. We observed that the average efficiency in hiPSCs was 43%±2% compared to 62%±4% in HEK 293 cells. Further analysis of the transfected hiPSCs showed that the differentiation of hiPSCs to hiPSC-CMs was not altered by NPs. Finally, robust transfection of hiPSC-CMs with an efficiency of 18%±2% was obtained.ConclusionThe difficult-to-transfect hiPSCs and hiPSC-CMs were efficiently transfected using magnetic NPs. Our study offers a novel approach for transfection of hiPSCs and hiPSC-CMs without the need for viral vector generation
The psychosocial impact of rare diseases among children and adolescents attending mainstream schools in Western Australia
Living with a long-term medical condition is associated with heightened risk for mental health and psychosocial difficulties, but further research is required on this risk for children and adolescents with a rare disease in the educational setting. The aim of this study is to describe parents’ perceptions of the psychosocial impact of rare diseases on their school-aged children in Western Australia. A cross-sectional survey of 41 parents of school-aged children and adolescents diagnosed with a rare disease completed an online questionnaire. Questions related to their perceptions of health-related stigma, bullying, social competencies and mental health difficulties faced by their child. Results showed that stigmatisation was experienced by 75.6% of participants, and almost half (46.4%) reported their child was bullied. In this sample, parents reported high sensory (vision and hearing) abilities, but low to moderate self-care competence in relation to social activities and peer relations. Almost half of the respondents (43.9%) reported mental health difficulties among their children. Children and adolescents with a rare disease have unique psychological and social issues. These findings highlight the need for greater efforts to meet the diverse psychosocial, physical and emotional needs of children diagnosed with a rare disease who attend mainstream schools in Western Australia
Analysis of thermal-hydraulic transients for the Miniature Neutron Source Reactor (MNSR) in Ghana
Abstract: A mathematical model is presented that permits to simulate the effect of the cooling coils of the pool upper section on the reactor thermal-hydraulic behaviour of Ghana research reactor-1. The model is based on a lumped parameter description solved numerically using Matlab/Simulink tool which is a commercial software package with the capability of modelling dynamical and control systems. The model incorporates fuel grids and cooling coil models as well as radiating energy from the clad. In this model, the reactor tank and the pool is divided into three sections. The model predictions are qualified by comparing the results with experimental data. The effect of cooling the upper section of the pool on reactor thermal-hydraulic parameters using the cooling coil is presented and discussed. It was observed that all maximum values of the reactor thermalhydraulic parameters decrease when the cooling coil power is increased. Good agreement is found between the model predictions and the experimental results
Res Medica, Spring 1966, Volume V, Number 2
TABLE OF CONTENTSNEUROLOGICAL EXAMINATION: J. B. Stanton F.R.C.P.E., F.R.C.P., D.P.M.THE FIELD OF ALLERGY: K. K. Adjepon-Yamoah, B.Sc.RES MEDICATHE SOCIETYÂ Â SEX CHROMOSOME ABNORMALITIES IN THE MALE: Patricia A. JacobsHEADACHE: Duncan L. Davidson, B.Sc.BOOK REVIEW
Enhancing life cycle product design decision-making processes: insights from normal accident theory and satisficing framework
Life Cycle Assessment (LCA), a computational tool used in sustainable product design decision making, faces challenges in the interpretation phase, where conclusions are drawn for improvement recommendations. This necessitate the need to incorporate into LCA management-relevant theoretical underpinnings to strengthen decision-making processes. Comparative LCA case studies of lead-based piezoelectric material (lead zirconate titanate – PZT) and lead-free alternatives
(potassium sodium niobate – KNN, sodium bismuth titanate – NBT), was employed to demonstrate how two theoretical lenses, namely Normal Accident Theory (NAT) and Satisficing Framework, are
used inductively to enhance decision making regarding unintended consequences in the value chain revealed by LCA outputs. The environmental analysis reveals NAT attributes of interactive complexity and tight coupling in piezoelectric materials, based on systems’ predictability, observability, and applicability, leading to the introduction of Environmental Impact Accident (EIA) as a new concept. EIA facilitates early assessment of the associated complexities influencing the sustainability credentials of piezoelectric materials, informing mitigation strategies. However, a conundrum is created when considering multiple objectives that conflict or trade-off between alternative piezoelectric materials with different environmental and health impacts across the value chain but was resolved using the Satisficing Framework. The paper concludes by proposing theoretical and practical policy options for incorporating LCA into product life cycle decision making
Enhancing life cycle product design decision-making processes : insights from normal accident theory and the satisficing framework
Life Cycle Assessment (LCA), a computational tool for enabling sustainable product design decision making, faces challenges in the interpretation phase, where conclusions are drawn for improvement recommendations. This necessitate the need to incorporate into LCA management-relevant theoretical underpinnings to strengthen decision-making processes. Comparative LCA case studies of lead-based piezoelectric material (lead zirconate titanate – PZT) and lead-free alternatives (potassium sodium niobate – KNN, sodium bismuth titanate – NBT), was employed to demonstrate how two theoretical lenses, namely Normal Accident Theory (NAT) and the Satisficing Framework, are used inductively to enhance decision making regarding unintended consequences in the value chain. By operationalising NAT, which has hitherto focused on the consequences of physical accidents, as a life cycle engineering-based methodology, NAT attributes of interactive complexity and tight coupling was revealed in piezoelectric materials, based on environmental systems’ predictability, observability, and applicability. This led to the introduction of Environmental Impact Accident (EIA) as a new concept, facilitating an early assessment of the associated complexities influencing the sustainability credentials of piezoelectric materials whilst informing mitigation strategies. However, when considering multiple objectives that conflict or trade-off between alternative piezoelectric materials with different environmental and health impacts across the value chain, a conundrum is created but resolved using the Satisficing Framework. The paper concludes by proposing theoretical and practical policy options for incorporating LCA into product life cycle decision making
International sourcing decisions in the wake of a food scandal
This research investigates whether and how the 2013 Horsemeat Scandal has altered European food retailers’ efforts to mitigate fraud in the international agri-food supply chain. We construct an econometric model that matches fraud alert data from the European Union (EU) Rapid Alert System for Food and Feed (RASFF) from 2006 to 2016 with annual data on bilateral trade flows. We find that—prior to the horsemeat scandal—detection of fraud along the supply chain induced a small amount of trade diversion toward third-country sources, but did not substantially affect total trade into the EU. In contrast, in the years after the scandal, the detection of fraud by international suppliers was substantially trade destructive. Detection of fraud reduced trade, not only with the country from which the fraudulent product originated, but also from third-country exporters of the same product. These findings extend beyond trade in meat products and to importing countries outside Western and Northern Europe
A critical review of the impacts of COVID-19 on the global economy and ecosystems and opportunities for circular economy strategies
The World Health Organization declared COVID-19 a global pandemic on the 11th of March, 2020, but the world is still reeling from its aftermath. Originating from China, cases quickly spread across the globe, prompting the implementation of stringent measures by world governments in efforts to isolate cases and limit the transmission rate of the virus. These measures have however shattered the core sustaining pillars of the modern world economies as global trade and cooperation succumbed to nationalist focus and competition for scarce supplies. Against this backdrop, this paper presents a critical review of the catalogue of negative and positive impacts of the pandemic and proffers perspectives on how it can be leveraged to steer towards a better, more resilient low-carbon economy. The paper diagnosed the danger of relying on pandemic-driven benefits to achieving sustainable development goals and emphasizes a need for a decisive, fundamental structural change to the dynamics of how we live. It argues for a rethink of the present global economic growth model, shaped by a linear economy system and sustained by profiteering and energy-gulping manufacturing processes, in favour of a more sustainable model recalibrated on circular economy (CE) framework. Building on evidence in support of CE as a vehicle for balancing the complex equation of accomplishing profit with minimal environmental harms, the paper outlines concrete sector-specific recommendations on CE-related solutions as a catalyst for the global economic growth and development in a resilient post-COVID-19 world
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