321 research outputs found

    Amplifier for scanning tunneling microscopy at MHz frequencies

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    Conventional scanning tunneling microscopy (STM) is limited to a bandwidth of circa 1kHz around DC. Here, we develop, build and test a novel amplifier circuit capable of measuring the tunneling current in the MHz regime while simultaneously performing conventional STM measurements. This is achieved with an amplifier circuit including a LC tank with a quality factor exceeding 600 and a home-built, low-noise high electron mobility transistor (HEMT). The amplifier circuit functions while simultaneously scanning with atomic resolution in the tunneling regime, i.e. at junction resistances in the range of giga-ohms, and down towards point contact spectroscopy. To enable high signal-to-noise and meet all technical requirements for the inclusion in a commercial low temperature, ultra-high vacuum STM, we use superconducting cross-wound inductors and choose materials and circuit elements with low heat load. We demonstrate the high performance of the amplifier by spatially mapping the Poissonian noise of tunneling electrons on an atomically clean Au(111) surface. We also show differential conductance spectroscopy measurements at 3MHz, demonstrating superior performance over conventional spectroscopy techniques. Further, our technology could be used to perform impedance matched spin resonance and distinguish Majorana modes from more conventional edge states

    Imagining new feminist futures:How feminist social movements contest the neoliberalization of feminism in an increasingly corporate‐dominated world

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    Increasingly it is argued that feminism has been co‐opted by neoliberal agendas: becoming more individualistic and losing touch with its wider social change objectives. The neoliberalization of feminism is driven in part by increased corporate power, including the growing role of corporations in governance arenas, and corporate social responsibility agendas. However, we turn to social movement theory to elucidate strategies that social movements, including feminist social movements, are adopting in such spaces. In so doing, we find that feminist activists are engaging with new political opportunities, mobilizing structures and strategic framing processes that emerge in the context of increasingly neoliberal and privatized governance systems. We suggest that despite the significant challenges to their agendas, far from being co‐opted by neoliberalism, feminist social movements remain robust, existing alongside and developing new strategies to contest the neoliberalization of feminism in a variety of innovative ways

    Study protocol to investigate the effect of a lifestyle intervention on body weight, psychological health status and risk factors associated with disease recurrence in women recovering from breast cancer treatment

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    Background Breast cancer survivors often encounter physiological and psychological problems related to their diagnosis and treatment that can influence long-term prognosis. The aim of this research is to investigate the effects of a lifestyle intervention on body weight and psychological well-being in women recovering from breast cancer treatment, and to determine the relationship between changes in these variables and biomarkers associated with disease recurrence and survival. Methods/design Following ethical approval, a total of 100 patients will be randomly assigned to a lifestyle intervention (incorporating dietary energy restriction in conjunction with aerobic exercise training) or normal care control group. Patients randomised to the dietary and exercise intervention will be given individualised healthy eating dietary advice and written information and attend moderate intensity aerobic exercise sessions on three to five days per week for a period of 24 weeks. The aim of this strategy is to induce a steady weight loss of up to 0.5 Kg each week. In addition, the overall quality of the diet will be examined with a view to (i) reducing the dietary intake of fat to ~25% of the total calories, (ii) eating at least 5 portions of fruit and vegetables a day, (iii) increasing the intake of fibre and reducing refined carbohydrates, and (iv) taking moderate amounts of alcohol. Outcome measures will include body weight and body composition, psychological health status (stress and depression), cardiorespiratory fitness and quality of life. In addition, biomarkers associated with disease recurrence, including stress hormones, estrogen status, inflammatory markers and indices of innate and adaptive immune function will be monitored. Discussion This research will provide valuable information on the effectiveness of a practical, easily implemented lifestyle intervention for evoking positive effects on body weight and psychological well-being, two important factors that can influence long-term prognosis in breast cancer survivors. However, the added value of the study is that it will also evaluate the effects of the lifestyle intervention on a range of biomarkers associated with disease recurrence and survival. Considered together, the results should improve our understanding of the potential role that lifestyle-modifiable factors could play in saving or prolonging lives

    Depletion of abscisic acid levels in roots of flooded Carrizo citrange (Poncirus trifoliata L. Raf. x Citrus sinensis L. Osb.) plants is a stress-specific response associated to the differential expression of PYR/PYL/RCAR receptors

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    [EN] Soil flooding reduces root abscisic acid (ABA) levels in citrus, conversely to what happens under drought. Despite this reduction, microarray analyses suggested the existence of a residual ABA signaling in roots of flooded Carrizo citrange seedlings. The comparison of ABA metabolism and signaling in roots of flooded and water stressed plants of Carrizo citrange revealed that the hormone depletion was linked to the upregulation of CsAOG, involved in ABA glycosyl ester (ABAGE) synthesis, and to a moderate induction of catabolism (CsCYP707A, an ABA 8'-hydroxylase) and buildup of dehydrophaseic acid (DPA). Drought strongly induced both ABA biosynthesis and catabolism (CsNCED1, 9-cis-neoxanthin epoxycarotenoid dioxygenase 1, and CsCYP707A) rendering a significant hormone accumulation. In roots of flooded plants, restoration of control ABA levels after stress release was associated to the upregulation of CsBGLU18 (an ABA beta-glycosidase) that cleaves ABAGE. Transcriptional profile of ABA receptor genes revealed a different induction in response to soil flooding (CsPYL5) or drought (CsPYL8). These two receptor genes along with CsPYL1 were cloned and expressed in a heterologous system. Recombinant CsPYL5 inhibited Delta NHAB1 activity in vitro at lower ABA concentrations than CsPYL8 or CsPYL1, suggesting its better performance under soil flooding conditions. Both stress conditions induced ABA-responsive genes CsABI5 and CsDREB2A similarly, suggesting the occurrence of ABA signaling in roots of flooded citrus seedlings. The impact of reduced ABA levels in flooded roots on CsPYL5 expression along with its higher hormone affinity reinforce the role of this ABA receptor under soil-flooding conditions and explain the expression of certain ABA-responsive genes.This work was supported by Ministerio de Economia y Competitividad (MINECO), Fondo Europeo de Desarrollo Regional (FEDER) and Universitat Jaume I through grants No. AGL201676574-R, UJI-B2016-23/UJI-B2016-24 to A.G-C. and V.A. and MINECO, FEDER and Consejo Superior de Investigaciones Cientificas (CSIC) through grant BIO2014-52537-R to P.L.R. S.I.Z. and M.M. were supported by predoctoral grants from Universitat Jaume I and Generalitat Valenciana, respectively. M.G.G. was recipient of a "JAE-DOC" contract from the CSIC. Mass spectrometry analyses were performed at the central facilities (Servei Central d'Instrumentacio Cientifica, SCIC) of Universitat Jaume I.Arbona, V.; Zandalinas, SI.; Manzi, M.; González Guzmán, M.; Rodríguez Egea, PL.; Gómez-Cadenas, A. (2017). Depletion of abscisic acid levels in roots of flooded Carrizo citrange (Poncirus trifoliata L. Raf. x Citrus sinensis L. Osb.) plants is a stress-specific response associated to the differential expression of PYR/PYL/RCAR receptors. Plant Molecular Biology. 93(6):623-640. https://doi.org/10.1007/s11103-017-0587-7S623640936Agarwal PK, Jha B (2010) Transcription factors in plants and ABA dependent and independent abiotic stress signalling. Biol Plant 54:201–212Agustí J, Merelo P, Cercós M, Tadeo FR, Talón M (2008) Ethylene-induced differential gene expression during abscission of citrus leaves. 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    Hydrophilic interaction liquid chromatography (HILIC) in proteomics

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    In proteomics, nanoflow multidimensional chromatography is now the gold standard for the separation of complex mixtures of peptides as generated by in-solution digestion of whole-cell lysates. Ideally, the different stationary phases used in multidimensional chromatography should provide orthogonal separation characteristics. For this reason, the combination of strong cation exchange chromatography (SCX) and reversed-phase (RP) chromatography is the most widely used combination for the separation of peptides. Here, we review the potential of hydrophilic interaction liquid chromatography (HILIC) as a separation tool in the multidimensional separation of peptides in proteomics applications. Recent work has revealed that HILIC may provide an excellent alternative to SCX, possessing several advantages in the area of separation power and targeted analysis of protein post-translational modifications

    The effect of intra-articular botulinum toxin A on substance P, prostaglandin E-2, and tumor necrosis factor alpha in the canine osteoarthritic joint

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    Background: Recently, intra-articular botulinum toxin A (IA BoNT A) has been shown to reduce joint pain in osteoarthritic dogs. Similar results have been reported in human patients with arthritis. However, the mechanism of the antinociceptive action of IA BoNT A is currently not known. The aim of this study was to explore this mechanism of action by investigating the effect of IA BoNT A on synovial fluid (SF) and serum substance P (SP), prostaglandin E-2 (PGE(2)), and tumor necrosis factor alpha (TNF-alpha) in osteoarthritic dogs. Additionally, the aim was to compare SF SP and PGE(2) between osteoarthritic and non-osteoarthritic joints, and investigate associations between SP, PGE(2), osteoarthritic pain, and the signalment of dogs. Thirty-five dogs with chronic naturally occurring osteoarthritis and 13 non-osteoarthritic control dogs were included in the study. Osteoarthritic dogs received either IA BoNT A (n = 19) or IA placebo (n = 16). Serum and SF samples were collected and osteoarthritic pain was evaluated before (baseline) and 2 and 8 weeks after treatment. Osteoarthritic pain was assessed with force platform, Helsinki Chronic Pain Index, and joint palpation. Synovial fluid samples were obtained from control dogs after euthanasia. The change from baseline in SP and PGE(2) concentration was compared between the IA BoNT A and placebo groups. The synovial fluid SP and PGE(2) concentration was compared between osteoarthritic and control joints. Associations between SP, PGE(2), osteoarthritic pain, and the signalment of dogs were evaluated. Results: There was no significant change from baseline in SP or PGE(2) after IA BoNT A. Synovial fluid PGE(2) was significantly higher in osteoarthritic compared to control joints. Synovial fluid PGE(2) correlated with osteoarthritic pain. No associations were found between SP or PGE2 and the signalment of dogs. The concentration of TNF-alpha remained under the detection limit of the assay in all samples. Conclusions: The results suggest that the antinociceptive effect of IA BoNT A in the joint might not be related to the inhibition of SP nor PGE(2). Synovial fluid PGE(2,) but not SP, could be a marker for chronic osteoarthritis and pain in dogs.Peer reviewe
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