75 research outputs found

    Structural, magnetic and electrical properties of the hexagonal ferrites MFeO3 (M=Y, Yb, In)

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    We thank EPSRC for funding, STFC for providing neutron facilities and Diamond Light Source for provision of synchrotron facilities. We thank Dr Chiu Tang for assistance at Diamond and Dr A. Kusmartseva (University of Edinburgh) for assistance with the SQUID measurements. FDM thanks the Royal Society for a Research Fellowship.The hexagonal ferrites MFeO3 (M=Y, Yb, In) have been studied using a combination of neutron and X-ray powder diffraction, magnetic susceptibility, dielectric measurements and 57Fe Mössbauer spectroscopy. This study confirms the previously reported crystal structure of InFeO3 (YAlO3 structure type, space group P63/mmc), but YFeO3 and YbFeO3 both show a lowering of symmetry to at most P63cm (ferrielectric YMnO3 structure type). However, Mössbauer spectroscopy shows at least two distinct Fe sites for both YFeO3 and YbFeO3 and we suggest that the best model to rationalise this involves phase separation into more than one similar hexagonal YMnO3-like phase. Rietveld analysis of the neutron diffraction data was carried out using two hexagonal phases as a simplest case scenario. In both YFeO3 and YbFeO3, distinct dielectric anomalies are observed near 130 K and 150 K, respectively. These are tentatively correlated with weak anomalies in magnetic susceptibility and lattice parameters, for YFeO3 and YbFeO3, respectively, which may suggest a weak magnetoelectric effect. Comparison of neutron and X-ray powder diffraction shows evidence of long-range magnetic order in both YFeO3 and YbFeO3 at low temperatures. Due to poor sample crystallinity, the compositional and structural effects underlying the phase separation and possible magnetoelectric phenomena cannot be ascertained.PostprintPeer reviewe

    Elevated plasma triglyceride concentration and risk of adverse clinical outcomes in 1.5 million people: a CALIBER linked electronic health record study

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    BACKGROUND: Assessing the spectrum of disease risk associated with hypertriglyceridemia is needed to inform potential benefits from emerging triglyceride lowering treatments. We sought to examine the associations between a full range of plasma triglyceride concentration with five clinical outcomes. METHODS: We used linked data from primary and secondary care for 15 M people, to explore the association between triglyceride concentration and risk of acute pancreatitis, chronic pancreatitis, new onset diabetes, myocardial infarction and all-cause mortality, over a median of 6-7 years follow up. RESULTS: Triglyceride concentration was available for 1,530,411 individuals (mean age 56·6 ± 15·6 years, 51·4% female), with a median of 1·3 mmol/L (IQR: 0.9.to 1.9). Severe hypertriglyceridemia, defined as > 10 mmol/L, was identified in 3289 (0·21%) individuals including 620 with > 20 mmol/L. In multivariable analyses, a triglyceride concentration > 20 mmol/L was associated with very high risk for acute pancreatitis (Hazard ratio (HR) 13·55 (95% CI 9·15-20·06)); chronic pancreatitis (HR 25·19 (14·91-42·55)); and high risk for diabetes (HR 5·28 (4·51-6·18)) and all-cause mortality (HR 3·62 (2·82-4·65)) when compared to the reference category of ≤ 1·7 mmol/L. An association with myocardial infarction, however, was only observed for more moderate hypertriglyceridaemia between 1.7 and 10 mmol/L. We found a risk interaction with age, with higher risks for all outcomes including mortality among those ≤ 40 years compared to > 40 years. CONCLUSIONS: We highlight an exponential association between severe hypertriglyceridaemia and risk of incident acute and chronic pancreatitis, new diabetes, and mortality, especially at younger ages, but not for myocardial infarction for which only moderate hypertriglyceridemia conferred risk

    KELCH F-BOX Protein Positively Influences Arabidopsis Seed Germination by Targeting PHYTOCHROME-INTERACTING FACTOR1

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    Seeds employ sensory systems that assess various environmental cues over time to maximize the successful transition from embryo to seedling. Here we show that the Arabidopsis F-BOX protein COLD TEMPERATURE-GERMINATING (CTG)-10, identified by activation tagging, is a positive regulator of this process. When overexpressed (OE), CTG10 hastens aspects of seed germination. CTG10 is expressed predominantly in the hypocotyl, and the protein is localized to the nucleus. CTG10 interacts with PHYTOCHROME-INTERACTING FACTOR 1 (PIF1) and helps regulate its abundance in planta. CTG10-OE accelerates the loss of PIF1 in light, increasing germination efficiency, while PIF1-OE lines fail to complete germination in darkness, which is reversed by concurrent CTG10-OE. Double-mutant (pif1 ctg10) lines demonstrated that PIF1 is epistatic to CTG10. Both CTG10 and PIF1 amounts decline during seed germination in the light but reaccumulate in the dark. PIF1 in turn down-regulates CTG10 transcription, suggesting a feedback loop of CTG10/PIF1 control. The genetic, physiological, and biochemical evidence, when taken together, leads us to propose that PIF1 and CTG10 coexist, and even accumulate, in the nucleus in darkness, but that, following illumination, CTG10 assists in reducing PIF1 amounts, thus promoting the completion of seed germination and subsequent seedling development

    Searching for musical features using natural language queries: the C@merata evaluations at MediaEval

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    Musicological texts about classical music frequently include detailed technical discussions concerning the works being analysed. These references can be specific (e.g. C sharp in the treble clef) or general (fugal passage, Thor’s Hammer).Experts can usually identify the features in question in music scores but a means of performing this task automatically could be very useful for experts and beginnersalike. Following work on textual question answering over many years as co-or-ganisers of the QA tasks at the Cross Language Evaluation Forum, we decided in 2013 to propose a new type of task where the input would be a natural language phrase, together with a music score in MusicXML, and the required output would be one or more matching passages in the score. We report here on 3 years of theC@merata task at MediaEval. We describe the design of the task, the evaluation methods we devised for it, the approaches adopted by participant systems and the results obtained. Finally, we assess the progress which has been made in aligning natural language text with music and map out the main steps for the future. The novel aspects of this work are: (1) the task itself, linking musical references to actual music scores, (2) the evaluation methods we devised, based on modified versions of precision and recall, applied to demarcated musical passages, and (3) the progress which has been made in analysing and interpreting detailed technical references to music within texts

    Nonlinear Time Series Analysis of Nodulation Factor Induced Calcium Oscillations: Evidence for Deterministic Chaos?

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    Legume plants form beneficial symbiotic interactions with nitrogen fixing bacteria (called rhizobia), with the rhizobia being accommodated in unique structures on the roots of the host plant. The legume/rhizobial symbiosis is responsible for a significant proportion of the global biologically available nitrogen. The initiation of this symbiosis is governed by a characteristic calcium oscillation within the plant root hair cells and this signal is activated by the rhizobia. Recent analyses on calcium time series data have suggested that stochastic effects have a large role to play in defining the nature of the oscillations. The use of multiple nonlinear time series techniques, however, suggests an alternative interpretation, namely deterministic chaos. We provide an extensive, nonlinear time series analysis on the nature of this calcium oscillation response. We build up evidence through a series of techniques that test for determinism, quantify linear and nonlinear components, and measure the local divergence of the system. Chaos is common in nature and it seems plausible that properties of chaotic dynamics might be exploited by biological systems to control processes within the cell. Systems possessing chaotic control mechanisms are more robust in the sense that the enhanced flexibility allows more rapid response to environmental changes with less energetic costs. The desired behaviour could be most efficiently targeted in this manner, supporting some intriguing speculations about nonlinear mechanisms in biological signaling

    An African Ancestry-Specific Allele of CTLA4 Confers Protection against Rheumatoid Arthritis in African Americans

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    Cytotoxic T-lymphocyte associated protein 4 (CTLA4) is a negative regulator of T-cell proliferation. Polymorphisms in CTLA4 have been inconsistently associated with susceptibility to rheumatoid arthritis (RA) in populations of European ancestry but have not been examined in African Americans. The prevalence of RA in most populations of European and Asian ancestry is ∼1.0%; RA is purportedly less common in black Africans, with little known about its prevalence in African Americans. We sought to determine if CTLA4 polymorphisms are associated with RA in African Americans. We performed a 2-stage analysis of 12 haplotype tagging single nucleotide polymorphisms (SNPs) across CTLA4 in a total of 505 African American RA patients and 712 African American controls using Illumina and TaqMan platforms. The minor allele (G) of the rs231778 SNP was 0.054 in RA patients, compared to 0.209 in controls (4.462×10−26, Fisher's exact). The presence of the G allele was associated with a substantially reduced odds ratio (OR) of having RA (AG+GG genotypes vs. AA genotype, OR 0.19, 95% CI: 0.13–0.26, p = 2.4×10−28, Fisher's exact), suggesting a protective effect. This SNP is polymorphic in the African population (minor allele frequency [MAF] 0.09 in the Yoruba population), but is very rare in other groups (MAF = 0.002 in 530 Caucasians genotyped for this study). Markers associated with RA in populations of European ancestry (rs3087243 [+60C/T] and rs231775 [+49A/G]) were not replicated in African Americans. We found no confounding of association for rs231778 after stratifying for the HLA-DRB1 shared epitope, presence of anti-cyclic citrullinated peptide antibody, or degree of admixture from the European population. An African ancestry-specific genetic variant of CTLA4 appears to be associated with protection from RA in African Americans. This finding may explain, in part, the relatively low prevalence of RA in black African populations

    Plasmodium falciparum Parasites Are Killed by a Transition State Analogue of Purine Nucleoside Phosphorylase in a Primate Animal Model

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    Plasmodium falciparum causes most of the one million annual deaths from malaria. Drug resistance is widespread and novel agents against new targets are needed to support combination-therapy approaches promoted by the World Health Organization. Plasmodium species are purine auxotrophs. Blocking purine nucleoside phosphorylase (PNP) kills cultured parasites by purine starvation. DADMe-Immucillin-G (BCX4945) is a transition state analogue of human and Plasmodium PNPs, binding with picomolar affinity. Here, we test BCX4945 in Aotus primates, an animal model for Plasmodium falciparum infections. Oral administration of BCX4945 for seven days results in parasite clearance and recrudescence in otherwise lethal infections of P. falciparum in Aotus monkeys. The molecular action of BCX4945 is demonstrated in crystal structures of human and P. falciparum PNPs. Metabolite analysis demonstrates that PNP blockade inhibits purine salvage and polyamine synthesis in the parasites. The efficacy, oral availability, chemical stability, unique mechanism of action and low toxicity of BCX4945 demonstrate potential for combination therapies with this novel antimalarial agent

    Promoting optimal parenting and children’s mental health : a preliminary evaluation of the How-to Parenting Program

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    Parenting quality is widely accepted as a primary predictor of children’s mental health. The present study examined the effectiveness of a parenting program in fostering optimal parenting and child mental health. The selected program was How to talk so kids will listen & listen so kids will talk (How-to Parenting Program). This program was selected because its content corresponds closely to what the parenting style literature suggests is optimal parenting (i.e., includes structure, affiliation and autonomy support). Eleven groups of six to twelve parents were conducted in 7 local grade schools. The program, offered by two trained leaders, consisted of eight weekly sessions and taught a total of 30 skills. A total of 82 parents completed questionnaires both prior to and after the program. Participants’ children between eight and 12 years old (N = 44) completed questionnaires at school, at both assessment points. Repeated measures ANOVAs using parent reports indicated that structure, affiliation and autonomy support were increased after the program, compared to baseline. The level of child internalizing and externalizing problems also decreased significantly. Importantly, children reports confirmed that parental autonomy support increased from pre to post-test and child-reported well-being improved as well. The preliminary evidence from this pre-test versus post-test repeated measures design suggests that the How-to Parenting Program is effective in improving parenting style and in promoting children’s mental health and that future evaluation research examining the potential of this program is warranted

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

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    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

    Structural, magnetic and electrical properties of the hexagonal ferrites MFeO<sub>3</sub> (M=Y, Yb, In)

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    The hexagonal ferrites MFeO3 (M=Y, Yb, In) have been studied using a combination of neutron and X-ray powder diffraction, magnetic susceptibility, dielectric measurements and 57Fe Mössbauer spectroscopy. This study confirms the previously reported crystal structure of InFeO3 (YAlO3 structure type, space group P63/mmc), but YFeO3 and YbFeO3 both show a lowering of symmetry to at most P63cm (ferrielectric YMnO3 structure type). However, Mössbauer spectroscopy shows at least two distinct Fe sites for both YFeO3 and YbFeO3 and we suggest that the best model to rationalise this involves phase separation into more than one similar hexagonal YMnO3-like phase. Rietveld analysis of the neutron diffraction data was carried out using two hexagonal phases as a simplest case scenario. In both YFeO3 and YbFeO3, distinct dielectric anomalies are observed near 130 K and 150 K, respectively. These are tentatively correlated with weak anomalies in magnetic susceptibility and lattice parameters, for YFeO3 and YbFeO3, respectively, which may suggest a weak magnetoelectric effect. Comparison of neutron and X-ray powder diffraction shows evidence of long-range magnetic order in both YFeO3 and YbFeO3 at low temperatures. Due to poor sample crystallinity, the compositional and structural effects underlying the phase separation and possible magnetoelectric phenomena cannot be ascertained
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