1,607 research outputs found

    Clustering of magnetic reconnection exhausts in the solar wind: An automated detection study

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    Context. Magnetic reconnection is a fundamental process in astrophysical plasmas that enables the dissipation of magnetic energy at kinetic scales. Detecting this process in situ is therefore key to furthering our understanding of energy conversion in space plasmas. However, reconnection jets typically scale from seconds to minutes in situ, and as such, finding them in the decades of data provided by solar wind missions since the beginning of the space era is an onerous task. Aims. In this work, we present a new approach for automatically identifying reconnection exhausts in situ in the solar wind. We apply the algorithm to Solar Orbiter data obtained while the spacecraft was positioned at between 0.6 and 0.8 AU and perform a statistical study on the jets we detect. Methods. The method for automatic detection is inspired by the visual identification process and strongly relies on the Walén relation. It is enhanced through the use of Bayesian inference and physical considerations to detect reconnection jets with a consistent approach. Results. Applying the detection algorithm to one month of Solar Orbiter data near 0.7 AU, we find an occurrence rate of seven jets per day, which is significantly higher than in previous studies performed at 1 AU. We show that they tend to cluster in the solar wind and are less likely to occur in the tenuous solar wind (< 10 cm−3 near 0.7 AU). We discuss why the source and the degree of Alfvénicity of the solar wind might have an impact on magnetic reconnection occurrence. Conclusions. By providing a tool to quickly identify potential magnetic reconnection exhausts in situ, we pave the way for broader statistical studies on magnetic reconnection in diverse plasma environments

    Cross-Attraction between an Exotic and a Native Pine Bark Beetle: A Novel Invasion Mechanism?

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    Aside from the ecological impacts, invasive species fascinate ecologists because of the unique opportunities that invasives offer in the study of community ecology. Some hypotheses have been proposed to illustrate the mechanisms that allow exotics to become invasive. However, positive interactions between exotic and native insects are rarely utilized to explain invasiveness of pests.Here, we present information on a recently formed association between a native and an exotic bark beetle on their shared host, Pinus tabuliformis, in China. In field examinations, we found that 35-40% of P. tabuliformis attacked by an exotic bark beetle, Dendroctonus valens, were also attacked by a native pine bark beetle, Hylastes parallelus. In the laboratory, we found that the antennal and walking responses of H. parallelus to host- and beetle-produced compounds were similar to those of the exotic D. valens in China. In addition, D. valens was attracted to volatiles produced by the native H. parallelus.We report, for the first time, facilitation between an exotic and a native bark beetle seems to involve overlap in the use of host attractants and pheromones, which is cross-attraction. The concept of this interspecific facilitation could be explored as a novel invasive mechanism which helps explain invasiveness of not only exotic bark beetles but also other introduced pests in principle. The results reported here also have particularly important implications for risk assessments and management strategies for invasive species

    tabAnti-HER2 (erbB-2) oncogene effects of phenolic compounds directly isolated from commercial Extra-Virgin Olive Oil (EVOO)

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    <p>Abstract</p> <p>Background</p> <p>The effects of the olive oil-rich Mediterranean diet on breast cancer risk might be underestimated when HER2 (<it>ERB</it>B2) oncogene-positive and HER2-negative breast carcinomas are considered together. We here investigated the anti-HER2 effects of phenolic fractions directly extracted from Extra Virgin Olive Oil (EVOO) in cultured human breast cancer cell lines.</p> <p>Methods</p> <p>Solid phase extraction followed by semi-preparative high-performance liquid chromatography (HPLC) was used to isolate phenolic fractions from commercial EVOO. Analytical capillary electrophoresis coupled to mass spectrometry was performed to check for the composition and to confirm the identity of the isolated fractions. EVOO polyphenolic fractions were tested on their tumoricidal ability against HER2-negative and HER2-positive breast cancer <it>in vitro </it>models using MTT, crystal violet staining, and Cell Death ELISA assays. The effects of EVOO polyphenolic fractions on the expression and activation status of HER2 oncoprotein were evaluated using HER2-specific ELISAs and immunoblotting procedures, respectively.</p> <p>Results</p> <p>Among the fractions mainly containing the <it>single phenols </it>hydroxytyrosol and tyrosol, the <it>polyphenol acid </it>elenolic acid, the <it>lignans </it>(+)-pinoresinol and 1-(+)-acetoxypinoresinol, and the <it>secoiridoids </it>deacetoxy oleuropein aglycone, ligstroside aglycone, and oleuropein aglycone, all the major EVOO polyphenols (<it>i.e. </it>secoiridoids and lignans) were found to induce strong tumoricidal effects within a micromolar range by selectively triggering high levels of apoptotic cell death in HER2-overexpressors. Small interfering RNA-induced depletion of HER2 protein and lapatinib-induced blockade of HER2 tyrosine kinase activity both significantly prevented EVOO polyphenols-induced cytotoxicity. EVOO polyphenols drastically depleted HER2 protein and reduced HER2 tyrosine autophosphorylation in a dose- and time-dependent manner. EVOO polyphenols-induced HER2 downregulation occurred regardless the molecular mechanism contributing to HER2 overexpression (<it>i.e</it>. naturally by gene amplification and ectopically driven by a viral promoter). Pre-treatment with the proteasome inhibitor MG132 prevented EVOO polyphenols-induced HER2 depletion.</p> <p>Conclusion</p> <p>The ability of EVOO-derived polyphenols to inhibit HER2 activity by promoting the proteasomal degradation of the HER2 protein itself, together with the fact that humans have safely been ingesting secoiridoids and lignans as long as they have been consuming olives and OO, support the notion that the stereochemistry of these phytochemicals might provide an excellent and safe platform for the design of new HER2-targeting agents.</p

    Diagnostic accuracy of post-mortem MRI for thoracic abnormalities in fetuses and children

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    OBJECTIVES: To compare the diagnostic accuracy of post-mortem magnetic resonance imaging (PMMR) specifically for non-cardiac thoracic pathology in fetuses and children, compared with conventional autopsy. METHODS: Institutional ethics approval and parental consent was obtained. A total of 400 unselected fetuses and children underwent PMMR before conventional autopsy, reported blinded to the other dataset. RESULTS: Of 400 non-cardiac thoracic abnormalities, 113 (28 %) were found at autopsy. Overall sensitivity and specificity (95 % confidence interval) of PMMR for any thoracic pathology was poor at 39.6 % (31.0, 48.9) and 85.5 % (80.7, 89.2) respectively, with positive predictive value (PPV) 53.7 % (42.9, 64.0) and negative predictive value (NPV) 77.0 % (71.8, 81.4). Overall agreement was 71.8 % (67.1, 76.2). PMMR was most sensitive at detecting anatomical abnormalities, including pleural effusions and lung or thoracic hypoplasia, but particularly poor at detecting infection. CONCLUSIONS: PMMR currently has relatively poor diagnostic detection rates for the commonest intra-thoracic pathologies identified at autopsy in fetuses and children, including respiratory tract infection and diffuse alveolar haemorrhage. The reasonable NPV suggests that normal thoracic appearances at PMMR exclude the majority of important thoracic lesions at autopsy, and so could be useful in the context of minimally invasive autopsy for detecting non-cardiac thoracic abnormalities. KEY POINTS: • PMMR has relatively poor diagnostic detection rates for common intrathoracic pathology • The moderate NPV suggests that normal PMMR appearances exclude most important abnormalities • Lung sampling at autopsy remains the "gold standard" for pulmonary pathology

    Initial response of young people with thyrotoxicosis to block and replace or dose titration thionamide

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    \ua9 2022 The authors Published by Bioscientifica Ltd.Objective: Patients with thyrotoxicosis are treated with anti-thyroid drug (ATD) using block and replace (BR) or a smaller, titrated dose of ATD (dose titration, DT). Design: A multi-centre, phase III, open-label trial of newly diagnosed paediatric thyrotoxicosis patients randomised to BR/DT. We compared the biochemical response to BR/DT in the first 6 months of therapy. Methods: Patients commenced 0.75 mg/kg carbimazole (CBZ) daily with randomisation to BR/DT. We examined baseline patient characteristics, CBZ dose, time to serum thyroid-stimulating hormone (TSH)/free thyroxine (FT4) normalisation and BMI Z-score change. Results: There were 80 patients (baseline) and 78 patients (61 female) at 6 months. Mean CBZ dose was 0.9 mg/kg/day (BR) and 0.5 mg/kg/day (DT). There was no difference in time to non-suppressed TSH concentration; 16 of 39 patients (BR) and 11 of 39 (DT) had suppressed TSH at 6 months. Patients with suppressed TSH had higher mean baseline FT4 levels (72.7 vs 51.7 pmol/L; 95% CI for difference 1.73, 31.7; P = 0.029). Time to normalise FT4 levels was reduced in DT (log-rank test, P = 0.049) with 50% attaining normal FT4 at 28 days (95% CI 25, 32) vs 35 days in BR (95% CI 28, 58). Mean BMI Z-score increased from 0.10 to 0.81 at 6 months (95% CI for difference 0.57, 0.86; P &lt; 0.001) and was greatest in patients with higher baseline FT4 concentrations. Conclusions: DT-treated patients normalised FT4 concentrations more quickly than BR. Overall, 94% of patients have normal FT4 levels after 6 months, but 33% still have TSH suppression. Excessive weight gain occurs with both BR and DT therapy

    Cell-type-specific profiling of protein-DNA interactions without cell isolation using targeted DamID with next-generation sequencing.

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    This protocol is an extension to: Nat. Protoc. 2, 1467-1478 (2007); doi:10.1038/nprot.2007.148; published online 7 June 2007The ability to profile transcription and chromatin binding in a cell-type-specific manner is a powerful aid to understanding cell-fate specification and cellular function in multicellular organisms. We recently developed targeted DamID (TaDa) to enable genome-wide, cell-type-specific profiling of DNA- and chromatin-binding proteins in vivo without cell isolation. As a protocol extension, this article describes substantial modifications to an existing protocol, and it offers additional applications. TaDa builds upon DamID, a technique for detecting genome-wide DNA-binding profiles of proteins, by coupling it with the GAL4 system in Drosophila to enable both temporal and spatial resolution. TaDa ensures that Dam-fusion proteins are expressed at very low levels, thus avoiding toxicity and potential artifacts from overexpression. The modifications to the core DamID technique presented here also increase the speed of sample processing and throughput, and adapt the method to next-generation sequencing technology. TaDa is robust, reproducible and highly sensitive. Compared with other methods for cell-type-specific profiling, the technique requires no cell-sorting, cross-linking or antisera, and binding profiles can be generated from as few as 10,000 total induced cells. By profiling the genome-wide binding of RNA polymerase II (Pol II), TaDa can also identify transcribed genes in a cell-type-specific manner. Here we describe a detailed protocol for carrying out TaDa experiments and preparing the material for next-generation sequencing. Although we developed TaDa in Drosophila, it should be easily adapted to other organisms with an inducible expression system. Once transgenic animals are obtained, the entire experimental procedure-from collecting tissue samples to generating sequencing libraries-can be accomplished within 5 d.This work was funded by a Wellcome Trust Senior Investigator Award (103792), Wellcome Trust Programme Grant (092545) and BBSRC Project Grant (BB/L00786X/1) to A.H.B. A.H.B acknowledges core funding to the Gurdon Institute from the Wellcome Trust (092096) and CRUK (C6946/A14492).This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/nprot.2016.08

    The Welfare Implications of Using Exotic Tortoises as Ecological Replacements

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    <div><h3>Background</h3><p>Ecological replacement involves the introduction of non-native species to habitats beyond their historical range, a factor identified as increasing the risk of failure for translocations. Yet the effectiveness and success of ecological replacement rely in part on the ability of translocatees to adapt, survive and potentially reproduce in a novel environment. We discuss the welfare aspects of translocating captive-reared non-native tortoises, <em>Aldabrachelys gigantea</em> and <em>Astrochelys radiata</em>, to two offshore Mauritian islands, and the costs and success of the projects to date.</p> <h3>Methodology/Principal Findings</h3><p>Because tortoises are long-lived, late-maturing reptiles, we assessed the progress of the translocation by monitoring the survival, health, growth, and breeding by the founders. Between 2000 and 2011, a total of 26 <em>A. gigantea</em> were introduced to Ile aux Aigrettes, and in 2007 twelve sexually immature <em>A. gigantea</em> and twelve male <em>A. radiata</em> were introduced to Round Island, Mauritius. Annual mortality rates were low, with most animals either maintaining or gaining weight. A minimum of 529 hatchlings were produced on Ile aux Aigrettes in 11 years; there was no potential for breeding on Round Island. Project costs were low. We attribute the success of these introductions to the tortoises’ generalist diet, habitat requirements, and innate behaviour.</p> <h3>Conclusions/Significance</h3><p>Feasibility analyses for ecological replacement and assisted colonisation projects should consider the candidate species’ welfare during translocation and in its recipient environment. Our study provides a useful model for how this should be done. In addition to serving as ecological replacements for extinct Mauritian tortoises, we found that releasing small numbers of captive-reared <em>A. gigantea</em> and <em>A. radiata</em> is cost-effective and successful in the short term. The ability to release small numbers of animals is a particularly important attribute for ecological replacement projects since it reduces the potential risk and controversy associated with introducing non-native species.</p> </div
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