308 research outputs found

    Controlled release of chlorhexidine from a HEMA-UDMA resin using a magnetic field

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    The authors thank Mr. Russell Bailey of Nanovision (QMUL) for help with SEM. Dong Luo thanks for the financial support from the China Scholarship Council during his PhD study. The authors would like to thank Adam Daykin and Queen Mary Innovation for providing funding via the Life Sciences Initiative Proof of Concept Fund

    Correction: Heteroleptic iron(ii) complexes of chiral 2,6-bis(oxazolin-2-yl)-pyridine (PyBox) and 2,6-bis(thiazolin-2-yl)pyridine ligands – the interplay of two different ligands on the metal ion spin state

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    Correction for ‘Heteroleptic iron(II) complexes of chiral 2,6-bis(oxazolin-2-yl)-pyridine (PyBox) and 2,6-bis(thiazolin-2-yl)pyridine ligands – the interplay of two different ligands on the metal ion spin state’ by Namrah Shahid et al., Dalton Trans., 2022, 51, 4262–4274, DOI: 10.1039/d2dt00393g

    Orientation Independent Chipless RFID Tag Using Novel Trefoil Resonators

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    In this paper, a compact and fully passive bit encoding circuit, capable of operating as a chipless radio frequency identification (RFID) tag is presented. The structure consists of novel concentric trefoil-shaped slot resonators realized using Rogers RT/duroid (R) 5880 laminate, occupying a physical footprint of 13.55 x 13.55 mm(2). Each resonating element is associated with a particular data bit, having a 1:1 resonator-to-bit correspondence. Bit sequences are configured through introducing modifications in the geometric structure either by addition or exclusion of each nested slot resonator. Such changes manifest directly in the electromagnetic signature of the tag as presence or absence of corresponding resonant peaks. The proposed 10-bit tag offers minimized inter-resonator mutual coupling and insensitivity to changes in polarization and incident angles thereby demonstrating orientation independent functionality. Moreover, error-free encoding is achieved through stabilizing the shift in resonant frequencies for a variety of different geometric configurations and orientation of the structure. The tag operates within the license-free ultrawideband ranging from 5.4 to 10.4 GHz, providing spectral bit capacity and bit density of 2 bits/GHz and 5.44 bits/cm(2) respectively

    Effect of discriminative plant-sugar feeding on the survival and fecundity of Anopheles gambiae

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    <p>Abstract</p> <p>Background</p> <p>A previous study showed for <it>Anopheles gambiae s.s</it>. a gradation of feeding preference on common plant species growing in a malaria holoendemic area in western Kenya. The present follow-up study determines whether there is a relationship between the mosquito's preferences and its survival and fecundity.</p> <p>Methods</p> <p>Groups of mosquitoes were separately given <it>ad libitum </it>opportunity to feed on five of the more preferred plant species (<it>Hamelia patens</it>, <it>Parthenium hysterophorus</it>, <it>Ricinus communis</it>, <it>Senna didymobotrya</it>, and <it>Tecoma stans</it>) and one of the less preferred species (<it>Lantana camara</it>). The mosquitoes were monitored daily for survival. Sugar solution (glucose 6%) and water were used as controls. In addition, the fecundity of mosquitoes on each plant after (i) only one blood meal (number of eggs oviposited), and (ii) after three consecutive blood meals (proportion of females ovipositing, number of eggs oviposited and hatchability of eggs), was determined. The composition and concentration of sugar in the fed-on parts of each plant species were determined using gas chromatography. Using SAS statistical package, tests for significant difference of the fitness values between mosquitoes exposed to different plant species were conducted.</p> <p>Results and Conclusion</p> <p><it>Anopheles gambiae </it>that had fed on four of the five more preferred plant species (<it>T. stans</it>, <it>S. didymobotrya</it>, <it>R. communis </it>and <it>H. patens</it>, but not <it>P. hysterophorus</it>) lived longer and laid more eggs after one blood meal, when compared with <it>An. gambiae </it>that had fed on the least preferred plant species <it>L. camara</it>. When given three consecutive blood-meals, the percentage of females that oviposited, but not the number of eggs laid, was significantly higher for mosquitoes that had previously fed on the four more preferred plant species. Total sugar concentration in the preferred plant parts was significantly correlated with survival and with the proportion of females that laid eggs. This effect was associated mainly with three sugar types, namely glucose, fructose, and gulose. Except for <it>P. hysterophorus</it>, the results suggest that feeding by mosquitoes on preferred plant species under natural conditions results in higher fitness-related benefits, and that the sugar content in preferred plant parts is largely responsible for these effects.</p

    Fetal Microchimeric Cells in Blood of Women with an Autoimmune Thyroid Disease

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    CONTEXT: Hashimoto's thyroiditis (HT) and Graves' disease (GD), two autoimmune thyroid diseases (AITD), occur more frequently in women than in men and show an increased incidence in the years following parturition. Persisting fetal cells could play a role in the development of these diseases. OBJECTIVE: Aim of this study was to detect and characterize fetal cells in blood of postpartum women with and without an AITD. PARTICIPANTS: Eleven patients with an AITD and ten healthy volunteers, all given birth to a son maximum 5 years before analysis, and three women who never had been pregnant, were included. None of them had any other disease of the thyroid which could interfere with the results obtained. METHODS: Fluorescence in situ hybridization (FISH) and repeated FISH were used to count the number of male fetal cells. Furthermore, the fetal cells were further characterized. RESULTS: In patients with HT, 7 to 11 fetal cells per 1.000.000 maternal cells were detected, compared to 14 to 29 fetal cells in patients with GD (p=0.0061). In patients with HT, mainly fetal CD8(+) T cells were found, while in patients with GD, fetal B and CD4(+) T cells were detected. In healthy volunteers with son, 0 to 5 fetal cells were observed, which was significantly less than the number observed in patients (p<0,05). In women who never had been pregnant, no male cells were detected. CONCLUSION: This study shows a clear association between fetal microchimeric cells and autoimmune thyroid diseases

    Reducing the health disparities of Indigenous Australians: time to change focus

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    Background: Indigenous peoples have worse health than non-Indigenous, are over-represented amongst the poor and disadvantaged, have lower life expectancies, and success in improving disparities is limited. To address this, research usually focuses on disadvantaged and marginalised groups, offering only partial understanding of influences underpinning slow progress. Critical analysis is also required of those with the power to perpetuate or improve health inequities. In this paper, using Australia as a case example, we explore the effects of ‘White’, Anglo-Australian cultural dominance in health service delivery to Indigenous Australians. We address the issue using race as an organising principle, underpinned by relations of power.Methods: Interviews with non-Indigenous medical practitioners in Western Australia with extensive experience in Indigenous health encouraged reflection and articulation of their insights into factors promoting or impeding quality health care to Indigenous Australians. Interviews were audio-taped and transcribed. An inductive, exploratory analysis identified key themes that were reviewed and interrogated in light of existing literature on health care to Indigenous people, race and disadvantage. The researchers’ past experience, knowledge and understanding of health care and Indigenous health assisted with data interpretation. Informal discussions were also held with colleagues working professionally in Indigenous policy, practice and community settings.Results: Racism emerged as a key issue, leading us to more deeply interrogate the role ‘Whiteness’ plays in Indigenous health care. While Whiteness can refer to skin colour, it also represents a racialized social structure where Indigenous knowledge, beliefs and values are subjugated to the dominant western biomedical model in policy and practice. Racism towards Indigenous patients in health services was institutional and interpersonal. Internalised racism was manifest when Indigenous patients incorporated racist attitudes and beliefs into their lived experience, lowering expectations and their sense of self-worth.Conclusions: Current health policies and practices favour standardised care where the voice of those who are marginalised is often absent. Examining the effectiveness of such models in reducing health disparities requires health providers to critically reflect on whether policies and practices promote or compromise Indigenous health and wellbeing - an important step in changing the discourse that places Indigenous people at the centre of the problem

    Development of the piggyBac transposable system for Plasmodium berghei and its application for random mutagenesis in malaria parasites

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    Background: The genome of a number of species of malaria parasites ( Plasmodium spp.) has been sequenced in the hope of identifying new drug and vaccine targets. However, almost one-half of predicted Plasmodium genes are annotated as hypothetical and are difficult to analyse in bulk due to the inefficiency of current reverse genetic methodologies for Plasmodium. Recently, it has been shown that the transposase piggyBac integrates at random into the genome of the human malaria parasite P. falciparum offering the possibility to develop forward genetic screens to analyse Plasmodium gene function. This study reports the development and application of the piggyBac transposition system for the rodent malaria parasite P. berghei and the evaluation of its potential as a tool in forward genetic studies. P. berghei is the most frequently used malaria parasite model in gene function analysis since phenotype screens throughout the complete Plasmodium life cycle are possible both in vitro and in vivo. Results: We demonstrate that piggyBac based gene inactivation and promoter-trapping is both easier and more efficient in P. berghei than in the human malaria parasite, P. falciparum. Random piggyBac-mediated insertion into genes was achieved after parasites were transfected with the piggyBac donor plasmid either when transposase was expressed either from a helper plasmid or a stably integrated gene in the genome. Characterization of more than 120 insertion sites demonstrated that more than 70 most likely affect gene expression classifying their protein products as non-essential for asexual blood stage development. The non-essential nature of two of these genes was confirmed by targeted gene deletion one of which encodes P41, an ortholog of a human malaria vaccine candidate. Importantly for future development of whole genome phenotypic screens the remobilization of the piggyBac element in parasites that stably express transposase was demonstrated. Conclusion: These data demonstrate that piggyBac behaved as an efficient and random transposon in P. berghei. Remobilization of piggyBac element shows that with further development the piggyBac system can be an effective tool to generate random genome-wide mutation parasite libraries, for use in large-scale phenotype screens in vitro and in viv

    Asenapine effects in animal models of psychosis and cognitive function

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    Asenapine, a novel psychopharmacologic agent in the development for schizophrenia and bipolar disorder, has high affinity for serotonergic, α-adrenergic, and dopaminergic receptors, suggesting potential for antipsychotic and cognitive-enhancing properties. The effects of asenapine in rat models of antipsychotic efficacy and cognition were examined and compared with those of olanzapine and risperidone. Amphetamine-stimulated locomotor activity (Amp-LMA; 1.0 or 3.0 mg/kg s.c.) and apomorphine-disrupted prepulse inhibition (Apo-PPI; 0.5 mg/kg s.c.) were used as tests for antipsychotic activity. Delayed non-match to place (DNMTP) and five-choice serial reaction (5-CSR) tasks were used to assess short-term spatial memory and attention, respectively. Asenapine doses varied across tasks: Amp-LMA (0.01–0.3 mg/kg s.c.), Apo-PPI (0.001–0.3 mg/kg s.c.), DNMTP (0.01–0.1 mg/kg s.c.), and 5-CSR (0.003–0.3 mg/kg s.c.). Asenapine was highly potent (active at 0.03 mg/kg) in the Amp-LMA and Apo-PPI assays. DNMTP or 5-CSR performance was not improved by asenapine, olanzapine, or risperidone. All agents (P &lt; 0.01) reduced DNMTP accuracy at short delays; post hoc analyses revealed that only 0.1 mg/kg asenapine and 0.3 mg/kg risperidone differed from vehicle. All active agents (asenapine, 0.3 mg/kg; olanzapine, 0.03–0.3 mg/kg; and risperidone, 0.01–0.1 mg/kg) significantly impaired 5-CSR accuracy (P &lt; 0.05). Asenapine has potent antidopaminergic properties that are predictive of antipsychotic efficacy. Asenapine, like risperidone and olanzapine, did not improve cognition in normal rats. Rather, at doses greater than those required for antipsychotic activity, asenapine impaired cognitive performance due to disturbance of motor function, an effect also observed with olanzapine and risperidone

    Removal of Heterologous Sequences from Plasmodium falciparum Mutants Using FLPe-Recombinase

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    Genetically-modified mutants are now indispensable Plasmodium gene-function reagents, which are also being pursued as genetically attenuated parasite vaccines. Currently, the generation of transgenic malaria-parasites requires the use of drug-resistance markers. Here we present the development of an FRT/FLP-recombinase system that enables the generation of transgenic parasites free of resistance genes. We demonstrate in the human malaria parasite, P. falciparum, the complete and efficient removal of the introduced resistance gene. We targeted two neighbouring genes, p52 and p36, using a construct that has a selectable marker cassette flanked by FRT-sequences. This permitted the subsequent removal of the selectable marker cassette by transient transfection of a plasmid that expressed a 37°C thermostable and enhanced FLP-recombinase. This method of removing heterologous DNA sequences from the genome opens up new possibilities in Plasmodium research to sequentially target multiple genes and for using genetically-modified parasites as live, attenuated malaria vaccines

    Numerical study of radiative Maxwell viscoelastic magnetized flow from a stretching permeable sheet with the Cattaneo–Christov heat flux model

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    In this article, the Cattaneo-Christov heat flux model is implemented to study non-Fourier heat and mass transfer in the magnetohydrodynamic (MHD) flow of an upper convected Maxwell (UCM) fluid over a permeable stretching sheet under a transverse constant magnetic field. Thermal radiation and chemical reaction effects are also considered. The nonlinear partial differential conservation equations for mass, momentum, energy and species conservation are transformed with appropriate similarity variables into a system of coupled, highly nonlinear ordinary differential equations with appropriate boundary conditions. Numerical solutions have been presented for the influence of elasticity parameter (), magnetic parameter (M2), suction/injection parameter (λ), Prandtl number (Pr), conduction-radiation parameter (Rd), sheet stretching parameter (A), Schmidt number (Sc), chemical reaction parameter (γ_c), modified Deborah number with respect to relaxation time of heat flux (i.e. non-Fourier Deborah number) on velocity components, temperature and concentration profiles using the successive Taylor series linearization method (STSLM) utilizing Chebyshev interpolating polynomials and Gauss-Lobatto collocation. The effects of selected parameters on skin friction coefficient, Nusselt number and Sherwood number are also presented with the help of tables. Verification of the STSLM solutions is achieved with existing published results demonstrating close agreement. Further validation of skin friction coefficient, Nusselt number and Sherwood number values computed with STSLM is included using Mathematica software shooting quadrature
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