529 research outputs found

    Designing CALL for learning Chinese characters

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    Despite the enormity of its quantity, printed or written forms of Chinese characters are composed from a limited number of common components. For example, the characters for pond( ), lake( ), stream( ), river ( ), sea( ) and ocean( ) all contain a component in common, a three-dot component representing water. When this clue is explicitly highlighted to students, the learning of Chinese characters can be greatly enhanced. Using a computer to help students to develop this kind of structural awareness about language learning has not yet been thoroughly examined. This paper reports on the design of CALL software based on a pedagogic method which helps students to develop the higher order skills to analyse and categorise Chinese characters by using components. The result of the classroom experiment has shown supportive evidence on the feasibility and the need of integrating the software with an affective and contextual way of teaching Chinese characters.postprin

    Experiential learning of HIV self-test among student nurses: A qualitative study

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    Background: There is increasing demand for HIV self-tests, and nurses play an important role in counselling and assisting in the testing process. Traditional lecture-based nursing education has not typically focused on self-testing procedures, and there is little understanding of clients' experiences of self-testing. Objectives: To understand the experiential learning (EL)of student nurses during the process of self-testing for HIV. Design: This study used a qualitative design. Settings: A college in northern Taiwan. Participants: We recruited a purposive sample of 30 nursing students. Methods: The OraQuick self-test was used as the self-testing tool in this study. After participants used the OraQuick self-test, they underwent a semi-structured interview during the post-test counselling period. All interview data were subjected to line-by-line content analysis. Results: We extracted nine themes of nursing students' experiences during experiential learning of HIV self-test. In the pre-test stage, they recalled possible risk behaviors for HIV infection, decided to complete the self-test alone or asked for significant others to accompany them, and endured emotional fluctuations immediately prior to the test. When waiting for the test results, they felt isolated from the outside world. Some participants also began questioning the accuracy and safety of the test, and either viewed the results immediately or later on. In the post-test stage, some participants reported being uncertain about the results. Participants reported a greater understanding of the personal impact of testing and revealed their needs for support. Some identified a sense of loss and linked this to the rapid and direct delivery of test results. Conclusions: Our results can be used to guide HIV-related education courses and prevention programs. Experiential learning has the potential to improve HIV pre and post-test counselling, as nurses develop both clinical knowledge and personal insight of the testing process

    Community-acquired Klebsiella pneumoniae meningitis in an alcoholic patient with an infected pancreatic pseudocyst; a case report and review of literature

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    We report a case of a 49-year-old male with a history of chronic alcoholism and evidence of a pancreatic pseudocyst on CT scanning. He presented with a 3-days history of fever, loss of appetite and upper abdominal pain. Blood cultures grew Klebsiella pneumoniae and he improved clinically with a seven-day course of intravenous co-amoxiclav and metronidazole. Two weeks later he was readmitted to hospital with impaired consciousness and septic shock, and died three days later in intensive care. Post mortem examination revealed bacterial meningitis and an infected pancreatic pseudocyst. Klebsiella pneumoniae was isolated from the pancreas and meninges

    Novel role for the innate immune receptor toll-like receptor 4 (TLR4) in the regulation of the wnt signaling pathway and photoreceptor apoptosis

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    Recent evidence has implicated innate immunity in regulating neuronal survival in the brain during stroke and other neurodegenerations. Photoreceptors are specialized light-detecting neurons in the retina that are essential for vision. In this study, we investigated the role of the innate immunity receptor TLR4 in photoreceptors. TLR4 activation by lipopolysaccharide (LPS) significantly reduced the survival of cultured mouse photoreceptors exposed to oxidative stress. With respect to mechanism, TLR4 suppressed Wnt signaling, decreased phosphorylation and activation of the Wnt receptor LRP6, and blocked the protective effect of the Wnt3a ligand. Paradoxically, TLR4 activation prior to oxidative injury protected photoreceptors, in a phenomenon known as preconditioning. Expression of TNFΞ± and its receptors TNFR1 and TNFR2 decreased during preconditioning, and preconditioning was mimicked by TNFΞ± antagonists, but was independent of Wnt signaling. Therefore, TLR4 is a novel regulator of photoreceptor survival that acts through the Wnt and TNFΞ± pathways. Β© 2012 Yi et al

    Impacts of climate change on plant diseases – opinions and trends

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    There has been a remarkable scientific output on the topic of how climate change is likely to affect plant diseases in the coming decades. This review addresses the need for review of this burgeoning literature by summarizing opinions of previous reviews and trends in recent studies on the impacts of climate change on plant health. Sudden Oak Death is used as an introductory case study: Californian forests could become even more susceptible to this emerging plant disease, if spring precipitations will be accompanied by warmer temperatures, although climate shifts may also affect the current synchronicity between host cambium activity and pathogen colonization rate. A summary of observed and predicted climate changes, as well as of direct effects of climate change on pathosystems, is provided. Prediction and management of climate change effects on plant health are complicated by indirect effects and the interactions with global change drivers. Uncertainty in models of plant disease development under climate change calls for a diversity of management strategies, from more participatory approaches to interdisciplinary science. Involvement of stakeholders and scientists from outside plant pathology shows the importance of trade-offs, for example in the land-sharing vs. sparing debate. Further research is needed on climate change and plant health in mountain, boreal, Mediterranean and tropical regions, with multiple climate change factors and scenarios (including our responses to it, e.g. the assisted migration of plants), in relation to endophytes, viruses and mycorrhiza, using long-term and large-scale datasets and considering various plant disease control methods

    In Vivo Delta Opioid Receptor Internalization Controls Behavioral Effects of Agonists

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    GPCRs regulate a remarkable diversity of biological functions, and are thus often targeted for drug therapies. Stimulation of a GPCR by an extracellular ligand triggers receptor signaling via G proteins, and this process is highly regulated. Receptor activation is typically accompanied by desensitization of receptor signaling, a complex feedback regulatory process of which receptor internalization is postulated as a key event. The in vivo significance of GPCR internalization is poorly understood. In fact, the majority of studies have been performed in transfected cell systems, which do not adequately model physiological environments and the complexity of integrated responses observed in the whole animal.In this study, we used knock-in mice expressing functional fluorescent delta opioid receptors (DOR-eGFP) in place of the native receptor to correlate receptor localization in neurons with behavioral responses. We analyzed the pain-relieving effects of two delta receptor agonists with similar signaling potencies and efficacies, but distinct internalizing properties. An initial treatment with the high (SNC80) or low (AR-M100390) internalizing agonist equally reduced CFA-induced inflammatory pain. However, subsequent drug treatment produced highly distinct responses. Animals initially treated with SNC80 showed no analgesic response to a second dose of either delta receptor agonist. Concomitant receptor internalization and G-protein uncoupling were observed throughout the nervous system. This loss of function was temporary, since full DOR-eGFP receptor responses were restored 24 hours after SNC80 administration. In contrast, treatment with AR-M100390 resulted in retained analgesic response to a subsequent agonist injection, and ex vivo analysis showed that DOR-eGFP receptor remained G protein-coupled on the cell surface. Finally SNC80 but not AR-M100390 produced DOR-eGFP phosphorylation, suggesting that the two agonists produce distinct active receptor conformations in vivo which likely lead to differential receptor trafficking.Together our data show that delta agonists retain full analgesic efficacy when receptors remain on the cell surface. In contrast, delta agonist-induced analgesia is abolished following receptor internalization, and complete behavioral desensitization is observed. Overall these results establish that, in the context of pain control, receptor localization fully controls receptor function in vivo. This finding has both fundamental and therapeutic implications for slow-recycling GPCRs

    Homozygous Deletion of Six Olfactory Receptor Genes in a Subset of Individuals with Beta-Thalassemia

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    Progress in the functional studies of human olfactory receptors has been largely hampered by the lack of a reliable experimental model system. Although transgenic approaches in mice could characterize the function of individual olfactory receptors, the presence of over 300 functional genes in the human genome becomes a daunting task. Thus, the characterization of individuals with a genetic susceptibility to altered olfaction coupled with the absence of particular olfactory receptor genes will allow phenotype/genotype correlations and vindicate the function of specific olfactory receptors with their cognate ligands. We characterized a 118 kb Ξ²-globin deletion and found that its 3β€² end breakpoint extends to the neighboring olfactory receptor region downstream of the Ξ²-globin gene cluster. This deletion encompasses six contiguous olfactory receptor genes (OR51V1, OR52Z1, OR51A1P, OR52A1, OR52A5, and OR52A4) all of which are expressed in the brain. Topology analysis of the encoded proteins from these olfactory receptor genes revealed that OR52Z1, OR52A1, OR52A5, and OR52A4 are predicted to be functional receptors as they display integral characteristics of G-proteins coupled receptors. Individuals homozygous for the 118 kb Ξ²-globin deletion are afflicted with Ξ²-thalassemia due to a homozygous deletion of the Ξ²-globin gene and have no alleles for the above mentioned olfactory receptors genes. This is the first example of a homozygous deletion of olfactory receptor genes in human. Although altered olfaction remains to be ascertained in these individuals, such a study can be carried out in Ξ²-thalassemia patients from Malaysia, Indonesia and the Philippines where this mutation is common. Furthermore, OR52A1 contains a Ξ³-globin enhancer, which was previously shown to confer continuous expression of the fetal Ξ³-globin genes. Thus, the hypothesis that Ξ²-thalassemia individuals, who are homozygous for the 118 kb deletion, may also have an exacerbation of their anemia due to the deletion of two copies of the Ξ³-globin enhancer element is worthy of consideration

    Regulation of IL-2 gene expression by Siva and FOXP3 in human T cells

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    <p>Abstract</p> <p>Background</p> <p>Severe autoinflammatory diseases are associated with mutations in the <it>Foxp3 </it>locus in both mice and humans. <it>Foxp3 </it>is required for the development, function, and maintenance of regulatory T cells (T<sub>regs</sub>), a subset of CD4 cells that suppress T cell activation and inflammatory processes. <it>Siva </it>is a pro-apoptotic gene that is expressed across a range of tissues, including CD4 T cells. Siva interacts with three tumor necrosis factor receptor (TNFR) family members that are constitutively expressed on T<sub>reg </sub>cells: CD27, GITR, and OX40.</p> <p>Results</p> <p>Here we report a biophysical interaction between FOXP3 and Siva. We mapped the interaction domains to Siva's C-terminus and to a central region of FOXP3. We showed that <it>Siva </it>repressed IL-2 induction by suppressing <it>IL-2 </it>promoter activity during T cell activation. Siva-1's repressive effect on <it>IL-2 </it>gene expression appears to be mediated by inhibition of NFkappaB, whereas FOXP3 repressed both NFkappaB and NFAT activity.</p> <p>Conclusions</p> <p>In summary, our data suggest that both <it>FOXP3 </it>and <it>Siva </it>function as negative regulators of IL-2 gene expression in T<sub>reg </sub>cells, via suppression of NFAT by <it>FOXP3 </it>and of NFkappaB by both <it>FOXP3 </it>and <it>Siva</it>. Our work contributes evidence for <it>Siva's </it>role as a T cell signalling mediator in addition to its known pro-apoptotic function. Though further investigations are needed, evidence for the biophysical interaction between FOXP3 and Siva invites the possibility that Siva may be important for proper T<sub>reg </sub>cell function.</p

    β€˜High risk’ clinical and inflammatory clusters in COPD of Chinese descent

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordIntroduction COPD is a heterogeneous disease demonstrating inter-individual variation. A high COPD prevalence in Chinese populations is described but little is known about disease clusters and prognostic outcomes in the Chinese population across South-East Asia. We aim to determine if clusters of Chinese patients with COPD exist and their association with systemic inflammation and clinical outcomes. Methods Chinese patients with stable COPD were prospectively recruited into two cohorts (derivation and validation) from six hospitals across three South-East Asian countries (Singapore, Malaysia and Hong Kong; n=1,480). Each patient was followed over two-years. Clinical data (including co-morbidities) were employed in unsupervised hierarchical clustering (followed by validation) to determine the existence of patient clusters and their prognostic outcome. Accompanying systemic cytokine assessments were performed in a subset (n=336) of COPD patients to determine if inflammatory patterns and associated networks characterised the derived clusters. Results Five patient clusters were identified including (1) Ex-tuberculosis (2) Diabetic (3) Low co-morbidity: low-risk (4) Low co-morbidity: high-risk and (5) cardiovascular. The β€˜cardiovascular’ and β€˜ex-tuberculosis’ clusters demonstrate highest mortality (independent of GOLD assessment) and illustrate diverse cytokine patterns with complex inflammatory networks. Conclusions We describe novel β€˜clusters’ of Chinese COPD patients, two of which represent β€˜high-risk’ clusters. The β€˜cardiovascular’ and β€˜ex-tuberculosis’ patient clusters exhibit high mortality, significant inflammation and complex cytokine networks. Clinical and inflammatory risk stratification of Chinese patients with COPD should be considered for targeted intervention to improve disease outcomes.Singapore Ministry of Health - National Medical Research CouncilSingapore Ministry of EducationNanyang Technological University, SingaporeEngineering and Physical Sciences Research Council (EPSRC

    Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

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    The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pTβ‰₯20 GeV and pseudorapidities {pipe}Ξ·{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}Ξ·{pipe}<0. 8) for jets with 60≀pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≀{pipe}Ξ·{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. Β© 2013 CERN for the benefit of the ATLAS collaboration
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