3,284,967 research outputs found

    Exploring atmospheric radon with airborne gamma-ray spectroscopy

    Get PDF
    222^{222}Rn is a noble radioactive gas produced along the 238^{238}U decay chain, which is present in the majority of soils and rocks. As 222^{222}Rn is the most relevant source of natural background radiation, understanding its distribution in the environment is of great concern for investigating the health impacts of low-level radioactivity and for supporting regulation of human exposure to ionizing radiation in modern society. At the same time, 222^{222}Rn is a widespread atmospheric tracer whose spatial distribution is generally used as a proxy for climate and pollution studies. Airborne gamma-ray spectroscopy (AGRS) always treated 222^{222}Rn as a source of background since it affects the indirect estimate of equivalent 238^{238}U concentration. In this work the AGRS method is used for the first time for quantifying the presence of 222^{222}Rn in the atmosphere and assessing its vertical profile. High statistics radiometric data acquired during an offshore survey are fitted as a superposition of a constant component due to the experimental setup background radioactivity plus a height dependent contribution due to cosmic radiation and atmospheric 222^{222}Rn. The refined statistical analysis provides not only a conclusive evidence of AGRS 222^{222}Rn detection but also a (0.96 ±\pm 0.07) Bq/m3^{3} 222^{222}Rn concentration and a (1318 ±\pm 22) m atmospheric layer depth fully compatible with literature data.Comment: 17 pages, 8 figures, 2 table

    MicroRNA-222 regulates muscle alternative splicing through Rbm24 during differentiation of skeletal muscle cells

    Get PDF
    A number of microRNAs have been shown to regulate skeletal muscle development and differentiation. MicroRNA-222 is downregulated during myogenic differentiation and its overexpression leads to alteration of muscle differentiation process and specialized structures. By using RNA-induced silencing complex (RISC) pulldown followed by RNA sequencing, combined with in silico microRNA target prediction, we have identified two new targets of microRNA-222 involved in the regulation of myogenic differentiation, Ahnak and Rbm24. Specifically, the RNA-binding protein Rbm24 is a major regulator of muscle-specific alternative splicing and its downregulation by microRNA-222 results in defective exon inclusion impairing the production of muscle-specific isoforms of Coro6, Fxr1 and NACA transcripts. Reconstitution of normal levels of Rbm24 in cells overexpressing microRNA-222 rescues muscle-specific splicing. In conclusion, we have identified a new function of microRNA-222 leading to alteration of myogenic differentiation at the level of alternative splicing, and we provide evidence that this effect is mediated by Rbm24 protei

    A one-way dissection of high-order compact scheme for the solution of 2D Poisson equation

    Get PDF
    We present a one-way dissection formulation of high-order compact scheme for the solution of 2D Poisson equation. One-way dissection is a type of matrix reordering, divide and conquers procedure. Efficient and concise compact schemes of 4th and 6th orders are derived using the truncation errors of the Taylors’ series expansion of the governing equation. The system is split into sub-domains and each sub-domain is treated separately. Two test problems are solved to show the fourth order performance of the scheme. The direct method is used to achieve a quick solution to the problems

    A formal theory for spatial representation and reasoning in biomedical ontologies

    Get PDF
    Objective: The objective of this paper is to demonstrate how a formal spatial theory can be used as an important tool for disambiguating the spatial information embodied in biomedical ontologies and for enhancing their automatic reasoning capabilities. Method and Materials: This paper presents a formal theory of parthood and location relations among individuals, called Basic Inclusion Theory (BIT). Since biomedical ontologies are comprised of assertions about classes of individuals (rather than assertions about individuals), we define parthood and location relations among classes in the extended theory BIT+Cl (Basic Inclusion Theory for Classes). We then demonstrate the usefulness of this formal theory for making the logical structure of spatial information more precise in two ontologies concerned with human anatomy: the Foundational Model of Anatomy (FMA) and GALEN. Results: We find that in both the FMA and GALEN, class-level spatial relations with different logical properties are not always explicitly distinguished. As a result, the spatial information included in these biomedical ontologies is often ambiguous and the possibilities for implementing consistent automatic reasoning within or across ontologies are limited. Conclusion: Precise formal characterizations of all spatial relations assumed by a biomedical ontology are necessary to ensure that the information embodied in the ontology can be fully and coherently utilized in a computational environment. This paper can be seen as an important beginning step toward achieving this goal, but much more work is along these lines is required

    Stable isotope ratios indicate that body condition in migrating passerines is influenced by winter habitat

    Get PDF
    Although predicted some time ago, there has been little success in demonstrating that the overall fitness of migratory birds depends on the combined influences of their experiences over all seasons. We used stable carbon isotope signatures (δ<sup>13</sup>C) in the claws of migrating black-throated blue warblers <i>Dendroica caerulescens</i> to infer their wintering habitats and investigated whether winter habitat selection can be linked to condition during migration. Resident bird species with low δ<sup>13</sup>C corresponded to selection of more mesic habitats, and migrating birds with low δ<sup>13</sup>C were in better condition than conspecifics with higher δ<sup>13</sup>C signatures. These findings concur with empirical observations on the wintering grounds, where dominants (mostly males) tend to exclude subordinates from mesic areas (considered to be high-quality habitats). We believe that variation in condition during migration may be one of the key factors determining differences in arrival times and condition at the breeding areas, which in turn have a major influence on reproductive success

    Exosome-mediated transfer of miR-222 is sufficient to increase tumor malignancy in melanoma

    Get PDF
    BACKGROUND: Growing evidence is showing that metastatic cell populations are able to transfer their characteristics to less malignant cells. Exosomes (EXOs) are membrane vesicles of endocytic origin able to convey their cargo of mRNAs, microRNAs (miRs), proteins and lipids from donors to proximal as well as distant acceptor cells. Our previous results indicated that miR-221&222 are key factors for melanoma development and dissemination. The aim of this study was to verify whether the tumorigenic properties associated with miR-222 overexpression can be also propagated by miR-222-containing EXOs. METHODS: EXOs were isolated by UltraCentrifugation or Exoquick-TC(®) methods. Preparations of melanoma-derived vesicles were characterized by using the Nanosight™ technology and the expression of exosome markers analyzed by western blot. The expression levels of endogenous and exosomal miRNAs were examined by real time PCR. Confocal microscopy was used to evaluate transfer and uptake of microvesicles from donor to recipient cells. The functional significance of exosomal miR-222 was estimated by analyzing the vessel-like process formation, as well as cell cycle rates, invasive and chemotactic capabilities. RESULTS: Besides microvesicle marker characterization, we evidenced that miR-222 exosomal expression mostly reflected its abundance in the cells of origin, correctly paralleled by repression of its target genes, such as p27Kip1, and induction of the PI3K/AKT pathway, thus confirming its functional implication in cancer. The possible differential significance of PI3K/AKT blockade was assessed by using the BKM120 inhibitor in miR-222-transduced cell lines. In addition, in vitro cultures showed that vesicles released by miR-222-overexpressing cells were able to transfer miR-222-dependent malignancy when taken-up by recipient primary melanomas. Results were confirmed by antagomiR-221&222 treatments and by functional observations after internalization of EXOs devoid of these miRs

    The use of tricaine methanesulfonate, clove oil, metomidate, and 2-phenoxyethanol for anesthesia induction in alewives (Alosa pseudoharengus)

    Get PDF
    Anesthetics are widely used in routine aquaculture operations to immobilize animals for tagging, spawning, handling, and vaccination. A number of anesthetics are currently available for finfish, but their efficacy and optimal dosage is highly species-specific. The efficacy of the anesthetic agents (tricaine methanesulfonate (MS-222), clove oil, metomidate, and 2-phenoxyethanol (2-PE)) was studied in adult, juvenile (133.3 ± 1.5 mm, 27.5 ± 8.9 g), and larval Alewives (Alosa pseudoharengus Wilson). In an initial trial, wild-caught adults were anesthetized with doses of 87.5-112.5 mg/L MS-222, 25-40 mg/L clove oil 0.5-5.0 mg/L metomidate and 0.125-0.550 mg/L 2-PE. Optimal doses for anesthesia were similar for larvae and juveniles, and were identified as: 75-100 mg/L MS-222, 40 mg/L clove oil, 5-7 mg/L metomidate, and 500 mg/L 2-PE. All juvenile fish survived 48 hours post-exposure to each optimal dose. In a longer-term (24 hour) sedation experiment, juvenile alewives were netted and exposed to low clove oil (2.5 and 5.0 mg/L) and metomidate (0.25 and 0.50 mg/L) doses, and plasma cortisol was measured. Fish exposed to the clove oil treatments exhibited a cortisol stress response that was prolonged in the higher dose treatment. No cortisol stress response was observed in the metomidate treatments. Overall, optimal acute anesthesia doses for alewives were similar to those reported for other species, and metomidate may be useful for longer-term sedation

    Biharmonic C-parallel Legendrian submanifolds in 7-dimensional Sasakian space forms

    Full text link
    This paper corrects the classification result for biharmonic C-parallel Legendrian submanifolds presented by D. Fetcu and C. Oniciuc in [Tohoku Math. J. 64 (2012), 195-222].Comment: 10 page

    HMGB1-Induced Cross Talk between PTEN and miRs 221/222 in Thyroid Cancer

    Get PDF
    High mobility group box 1 (HMGB1) is an ubiquitous protein that plays different roles in the nucleus, cytoplasm and extra-cellular space. It is an important DAMP molecule that allows communication between damaged or tumor cells and the immune system. Tumor cells exploit HMGB1’s ability to activate intracellular pathways that lead to cell growth and migration. Papillary thyroid cancer is a well differentiated tumor and is often used to study relationships between cells and the inflammatory microenvironment as the latter is characterized by high levels of inflammatory cells and cytokines. Anaplastic thyroid cancer is one of the most lethal human cancers in which many microRNAs and tumor suppressor genes are de-regulated. Up-regulation of microRNAs 221 and 222 has been shown to induce the malignant phenotype in many human cancers via inhibition of PTEN expression. In this study we suggest that extracellular HMGB1 interaction with RAGE enhances expression of oncogenic cluster miR221/222 that in turn inhibits tumor suppressor gene PTEN in two cell lines derived from human thyroid anaplastic and papillary cancers. The newly identified pathway HMGB1/RAGE/miR 221/222 may represent an effective way of tumor escape from immune surveillance that could be used to develop new therapeutic strategies against anaplastic tumors
    corecore