3,287 research outputs found

    Introduction to Special Section: Integrated Geophysical Imaging

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    This special section illustrates the value of integration with nonseismic geophysical methods, namely potential fields (gravity and magnetics) and electric and electromagnetic techniques. The primary objective is to overcome the overall underappreciation of these methods as exploration tools. We provide their brief overview and present nine case studies illustrating how the integrative approach to geophysical data analysis influences the overall result and reduces the uncertainty of the derived solution

    Invariance under outer inverses

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    We shall use the minus partial order combined with Pierce’s decomposition to derive the class of outer inverses for idempotents, units and group invertible elements. Subsequently we show, for matrices over a field F, that the triplet BA^ C is invariant under all choices of outer inverses of A if and only if B= 0 or C= 0.FCT - Fundação para a Ciência e a Tecnologia (UID-MAT-00013/2013)info:eu-repo/semantics/publishedVersio

    A Systematic Comparison of 18F-C-SNAT to Established Radiotracer Imaging Agents for the Detection of Tumor Response to Treatment

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    PURPOSE: An early readout of tumor response to therapy through measurement of drug or radiation-induced cell death may provide important prognostic indications and improved patient management. It has been shown that the uptake of (18)F-C-SNAT can be used to detect early response to therapy in tumors by positron emission tomography (PET) via a mechanism of caspase-3-triggered nanoaggregation. EXPERIMENTAL DESIGN: Here, we compared the preclinical utility of (18)F-C-SNAT for the detection of drug-induced cell death to clinically evaluated radiotracers, (18)F-FDG, (99m)Tc-Annexin V, and (18)F-ML-10 in tumor cells in culture, and in tumor-bearing mice in vivo. RESULTS: In drug-treated lymphoma cells, (18)F-FDG, (99m)Tc-Annexin V, and (18)F-C-SNAT cell-associated radioactivity correlated well to levels of cell death (R(2) > 0.8; P 0.05). A similar pattern of response was observed in two human NSCLC cell lines following carboplatin treatment. EL-4 tumor uptake of (99m)Tc-Annexin V and (18)F-C-SNAT were increased 1.4- and 2.1-fold, respectively, in drug-treated versus naïve control animals (P < 0.05), although (99m)Tc-Annexin V binding did not correlate to ex vivo TUNEL staining of tissue sections. A differential response was not observed with either (18)F-FDG or (18)F-ML-10. CONCLUSIONS: We have demonstrated here that (18)F-C-SNAT can sensitively detect drug-induced cell death in murine lymphoma and human NSCLC. Despite favorable image contrast obtained with (18)F-C-SNAT, the development of next-generation derivatives, using the same novel and promising uptake mechanism, but displaying improved biodistribution profiles, are warranted for maximum clinical utility

    Microcystic cyanobacteria extract induces cytoskeletal disruption and intracellular glutathione alteration in hepatocytes.

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    Microcystins are a group of highly liver-specific toxins, although their exact mechanisms of action remain unclear. We examined the effects of microcystic cyanobacteria extract (MCE) collected from a contaminated water source on the organization of cellular microtubules (MTs) and microfilaments (MFs) in hepatocytes. We also investigated the effects on lactate dehydrogenase (LDH) leakage and intracellular glutathione (GSH). Primary cultured rat hepatocytes exposed to MCE (equivalent to 125 microg/mL lyophilized algae cells) showed a characteristic disruption of MTs and MFs in a time-dependent manner. Under these conditions, MCE caused aggregation of MTs and MFs and a severe loss of MTs in some cells. Moreover, MCE-induced cytoskeletal alterations preceded the LDH leakage. On the other hand, the treatment of cells with MCE led to a dose-dependent increase of intracellular GSH. However, time-course study showed a biphasic change of intracellular GSH levels with a significant increase in the initial stage followed by a decrease after prolonged treatment. Furthermore, pretreatment with N-acetylcystein (NAC), a GSH precursor, significantly enhanced the intracellular GSH level and decreased the MCE-induced cytotoxicity as well as cytoskeleton changes. In contrast, buthionine-(S, R)-sulfoximine, a specific GSH synthesis inhibitor, increased the cell susceptibility to MCE-induced cytotoxicity by depleting the intracellular GSH level. These findings suggest that intracellular GSH plays an important role in MCE-induced cytotoxicity and cytoskeleton changes in primary cultured rat hepatocytes. Increasing intracellular GSH levels protect cells from MCE-induced cytotoxicity and cytoskeleton changes

    In trans early mosaic mutational escape and novel phenotypic features of germline SAMD9 mutation

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    Influence of Microstructure on Ultrasonic Velocity in Nimonic Alloy PE16

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    Superalloys are widely used for many advanced applications. The alloys with optimum properties are obtained by introducing suitable microstructure through thermomechanical treatments. Characterization of microstructure and determination of mechanical properties of these alloys using ultrasonic parameters should help in quality control during heat treatment and identifying changes in microstructure during service. This study is aimed at demonstrating such a possibility in a selected precipitation hardenable nickel base superalloy, Nimonic alloy PE16. As part of this study, the influence of various secondary phases, γ′, MC and M23C6 on ultrasonic velocity is reported. Ultrasonic velocity has been selected as this parameter had been widely used for microstructural characterization and mechanical property determination in various materials [1–6]. γ′ is a coherent and ordered FCC phase having composition Ni3 (Al, Ti). The strengthening is achieved by the presence of γ′ in the microstructure. MC and M23C6 are respectively the Ti rich (Ti, Mo) C and Cr rich (Cr, Fe)23C6 carbides. The carbide phases are introduced to obtain better high temperature creep properties

    Remotely acting SMCHD1 gene regulatory elements: in silico prediction and identification of potential regulatory variants in patients with FSHD

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    Background: Facioscapulohumeral dystrophy (FSHD) is commonly associated with contraction of the D4Z4 macro-satellite repeat on chromosome 4q35 (FSHD1) or mutations in the SMCHD1 gene (FSHD2). Recent studies have shown that the clinical manifestation of FSHD1 can be modified by mutations in the SMCHD1 gene within a given family. The absence of either D4Z4 contraction or SMCHD1 mutations in a small cohort of patients suggests that the disease could also be due to disruption of gene regulation. In this study, we postulated that mutations responsible for exerting a modifier effect on FSHD might reside within remotely acting regulatory elements that have the potential to interact at a distance with their cognate gene promoter via chromatin looping. To explore this postulate, genome-wide Hi-C data were used to identify genomic fragments displaying the strongest interaction with the SMCHD1 gene. These fragments were then narrowed down to shorter regions using ENCODE and FANTOM data on transcription factor binding sites and epigenetic marks characteristic of promoters, enhancers and silencers

    A pp-adic Approach to the Weil Representation of Discriminant Forms Arising from Even Lattices

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    Suppose that MM is an even lattice with dual MM^{*} and level NN. Then the group Mp2(Z)Mp_{2}(\mathbb{Z}), which is the unique non-trivial double cover of SL2(Z)SL_{2}(\mathbb{Z}), admits a representation ρM\rho_{M}, called the Weil representation, on the space C[M/M]\mathbb{C}[M^{*}/M]. The main aim of this paper is to show how the formulae for the ρM\rho_{M}-action of a general element of Mp2(Z)Mp_{2}(\mathbb{Z}) can be obtained by a direct evaluation which does not depend on ``external objects'' such as theta functions. We decompose the Weil representation ρM\rho_{M} into pp-parts, in which each pp-part can be seen as subspace of the Schwartz functions on the pp-adic vector space MQpM_{\mathbb{Q}_{p}}. Then we consider the Weil representation of Mp2(Qp)Mp_{2}(\mathbb{Q}_{p}) on the space of Schwartz functions on MQpM_{\mathbb{Q}_{p}}, and see that restricting to Mp2(Z)Mp_{2}(\mathbb{Z}) just gives the pp-part of ρM\rho_{M} again. The operators attained by the Weil representation are not always those appearing in the formulae from 1964, but are rather their multiples by certain roots of unity. For this, one has to find which pair of elements, lying over a matrix in SL2(Qp)SL_{2}(\mathbb{Q}_{p}), belong to the metaplectic double cover. Some other properties are also investigated.Comment: 29 pages, shortened a lo

    Hierarchical semantic representations of online news comments for emotion tagging using multiple information sources

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    With the development of online news services, users now can actively respond to online news by expressing subjective emotions, which can help us understand the predilections and opinions of an individual user, and help news publishers to provide more relevant services. Neural network methods have achieved promising results, but still have challenges in the field of emotion tagging. Firstly, these methods regard the whole document as a stream or bag of words and can't encode the intrinsic relations between sentences. So these methods cannot properly express the semantic meaning of the document in which sentences may have logical relations. Secondly, these methods only use semantics of the document itself, while ignoring the accompanying information sources, which can significantly influence the interpretation of the sentiment contained in documents. Therefore, this paper presents a hierarchical semantic representation model of news comments using multiple information sources, called Hierarchical Semantic Neural Network (HSNN). In particular, we begin with a novel neural network model to learn document representation in a bottom-up way, capturing not only the semantics within sentence but also semantics or logical relations between sentences. On top of this, we tackle the task of predicting emotions for online news comments by exploiting multiple information sources including the content of comments, the content of news articles, and the user-generated emotion votes. A series of experiments and tests on real-world datasets have demonstrated the effectiveness of our proposed approach

    In Vitro and in Vivo Antioxidant Properties of the Plant-Based Supplement Greens+™

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    Dietary antioxidants play an important role against oxidation, an underlying mechanism in the incidence of chronic diseases. Greens+ is a commercially available preparation containing a variety of plant-derived ingredients. The aim of the current study was to evaluate the antioxidant potential of the methanolic extract of greens+ powder using in vitro and in vivo techniques. In vitro studies were conducted using a liposome model system to simulate biological cell membranes. Total antioxidant potential and polyphenol content of the herbal preparation was measured. For in vivo analysis, 10 healthy human subjects consumed either three or six teaspoons of greens+ per day for four weeks. Blood samples were analyzed at baseline and at the conclusion of the treatment period for total antioxidant capacity, polyphenol content, protein, lipid and LDL oxidation, and the level of glutathione peroxidase. Results showed that greens+ supplementation was well tolerated and increased serum antioxidant potential at higher levels of intake in a dose-dependent manner. HPLC analysis showed the presence of quercetin, apigenin, kaempferol and luteolin in the supplement. Plasma analysis indicated the presence of kaempferol only. A statistically significant (p < 0.05) reduction in protein and lipid oxidation was observed. Based on its antioxidant properties, the results suggest that greens+ might play a role in reducing the risk of chronic diseases involving a burden of oxidative damage
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