1,677 research outputs found

    Public exhibit for demonstrating the quantum of electrical conductance

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    We present a new robust setup that explains and demonstrates the quantum of electrical conductance for a general audience and which is continuously available in a public space. The setup allows users to manually thin a gold wire of several atoms in diameter while monitoring its conductance in real time. During the experiment, a characteristic step-like conductance decrease due to rearrangements of atoms in the cross-section of the wire is observed. Just before the wire breaks, a contact consisting of a single atom with a characteristic conductance close to the quantum of conductance can be maintained up to several seconds. The setup is operated full-time, needs practically no maintenance and is used on different educational levels

    Crystal IS on the move

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    Introduction: Whether pediatric patients with differentiated thyroid carcinoma (DTC) are at risk of developing treatment-related adverse effects on cardiac function is unknown. We therefore studied in long-term survivors of pediatric DTC the prevalence of cardiac dysfunction and atrial fibrillation in relation to treatment variables, and the association between cardiac dysfunction and plasma biomarkers. Methods: In this nationwide prospective multicenter study, cardiac assessments were performed in 66 adult survivors of pediatric DTC (age at diagnosis 18 years and follow-up 5 years after diagnosis) treated in the Netherlands between 1970 and 2009. Assessment included echocardiography, plasma biomarkers (N-terminal pro-brain natriuretic peptide, high-sensitive troponin-T, galectin-3), and 24-hour Holter electrocardiography. Echocardiographic measurements were compared with retrospective data of 66 sex- and age-matched unaffected Dutch controls. Diastolic dysfunction was defined as an early diastolic septal and/or lateral tissue velocity (e) less than 2 SD of mean age-adjusted reference data. Results: The survivors (86.4% women) had at DTC diagnosis a median age of 16 years. Median follow-up was 17 years. Left ventricular ejection fraction <50% was found in one survivor, and median global longitudinal systolic strain was near normal. Diastolic dysfunction was present in 14 asymptomatic survivors (21.2%). Overall, diastolic function of survivors was lower compared with controls (emean 14.5 versus 15.8cm/s, P=0.006). Older attained age and higher waist circumference were associated with decreased diastolic function, whereas thyrotropin levels and cumulative administered radioiodine dose were not. In survivors, biomarkers were not associated with diastolic dysfunction; atrial fibrillation was not observed. Conclusion: While systolic function is unaffected, diastolic dysfunction is frequently observed in asymptomatic long-term survivors of pediatric DTC, which may suggest early cardiac agin

    Effect of Spatial Charge Inhomogeneity on 1/f Noise Behavior in Graphene

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    Scattering mechanisms in graphene are critical to understanding the limits of signal-to-noise-ratios of unsuspended graphene devices. Here we present the four-probe low frequency noise (1/f) characteristics in back-gated single layer graphene (SLG) and bilayer graphene (BLG) samples. Contrary to the expected noise increase with the resistance, the noise for SLG decreases near the Dirac point, possibly due to the effects of the spatial charge inhomogeneity. For BLG, a similar noise reduction near the Dirac point is observed, but with a different gate dependence of its noise behavior. Some possible reasons for the different noise behavior between SLG and BLG are discussed.Comment: 28 pages, 3 figures + 3 supplement figure

    Non-targeting siRNA induces NPGPx expression to cooperate with exoribonuclease XRN2 for releasing the stress

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    Short interfering RNAs (siRNAs) target specific mRNAs for their degradation mediated by RNA-induced silencing complex (RISC). Persistent activation of siRNA-RISC frequently leads to non-targeting toxicity. However, how cells mediate this stress remains elusive. In this communication, we found that the presence of non-targeting siRNA selectively induced the expression of an endoplasmic reticulum (ER)-resident protein, non-selenocysteine containing phospholipid hydroperoxide glutathione peroxidase (NPGPx), but not other ER-stress proteins including GRP78, Calnexin and XBP1. Cells suffering from constant non-targeting siRNA stress grew slower and prolonged G1 phase, while NPGPx-depleted cells accumulated mature non-targeting siRNA and underwent apoptosis. Upon the stress, NPGPx covalently bound to exoribonuclease XRN2, facilitating XRN2 to remove accumulated non-targeting siRNA. These results suggest that NPGPx serves as a novel responder to non-targeting siRNA-induced stress in facilitating XRN2 to release the non-targeting siRNA accumulation

    GP-initiated preconception counselling in a randomised controlled trial does not induce anxiety

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    BACKGROUND: Preconception counselling (PCC) can reduce adverse pregnancy outcome by addressing risk factors prior to pregnancy. This study explores whether anxiety is induced in women either by the offer of PCC or by participation with GP-initiated PCC. METHODS: Randomised trial of usual care versus GP-initiated PCC for women aged 18–40, in 54 GP practices in the Netherlands. Women completed the six-item Spielberger State Trait Anxiety Inventory (STAI) before PCC (STAI-1) and after (STAI-2). After pregnancy women completed a STAI focusing on the first trimester of pregnancy (STAI-3). RESULTS: The mean STAI-1-score (n = 466) was 36.4 (95% CI 35.4 – 37.3). Following PCC there was an average decrease of 3.6 points in anxiety-levels (95% CI, 2.4 – 4.8). Mean scores of the STAI-3 were 38.5 (95% CI 37.7 – 39.3) in the control group (n = 1090) and 38.7 (95% CI 37.9 – 39.5) in the intervention group (n = 1186). CONCLUSION: PCC from one's own GP reduced anxiety after participation, without leading to an increase in anxiety among the intervention group during pregnancy. We therefore conclude that GPs can offer PCC to the general population without fear of causing anxiety. Trial Registration: ISRCTN5394291

    Improved PCR based methods for detecting C9orf72 hexanucleotide repeat expansions

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    Due to the GC-rich, repetitive nature of C9orf72 hexanucleotide repeat expansions, PCR based detection methods are challenging. Several limitations of PCR have been reported and overcoming these could help to define the pathogenic range. There is also a need to develop improved repeat-primed PCR assays which allow detection even in the presence of genomic variation around the repeat region. We have optimised PCR conditions for the C9orf72 hexanucleotide repeat expansion, using betaine as a co-solvent and specific cycling conditions, including slow ramping and a high denaturation temperature. We have developed a flanking assay, and repeat-primed PCR assays for both 3′ and 5′ ends of the repeat expansion, which when used together provide a robust strategy for detecting the presence or absence of expansions greater than ∼100 repeats, even in the presence of genomic variability at the 3′ end of the repeat. Using our assays, we have detected repeat expansions in 47/442 Scottish ALS patients. Furthermore, we recommend the combined use of these assays in a clinical diagnostic setting

    FMAP: Distributed Cooperative Multi-Agent Planning

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    This paper proposes FMAP (Forward Multi-Agent Planning), a fully-distributed multi-agent planning method that integrates planning and coordination. Although FMAP is specifically aimed at solving problems that require cooperation among agents, the flexibility of the domain-independent planning model allows FMAP to tackle multi-agent planning tasks of any type. In FMAP, agents jointly explore the plan space by building up refinement plans through a complete and flexible forward-chaining partial-order planner. The search is guided by h D T G , a novel heuristic function that is based on the concepts of Domain Transition Graph and frontier state and is optimized to evaluate plans in distributed environments. Agents in FMAP apply an advanced privacy model that allows them to adequately keep private information while communicating only the data of the refinement plans that is relevant to each of the participating agents. Experimental results show that FMAP is a general-purpose approach that efficiently solves tightly-coupled domains that have specialized agents and cooperative goals as well as loosely-coupled problems. Specifically, the empirical evaluation shows that FMAP outperforms current MAP systems at solving complex planning tasks that are adapted from the International Planning Competition benchmarks.This work has been partly supported by the Spanish MICINN under projects Consolider Ingenio 2010 CSD2007-00022 and TIN2011-27652-C03-01, the Valencian Prometeo project II/2013/019, and the FPI-UPV scholarship granted to the first author by the Universitat Politecnica de Valencia.Torreño Lerma, A.; Onaindia De La Rivaherrera, E.; Sapena Vercher, O. (2014). FMAP: Distributed Cooperative Multi-Agent Planning. Applied Intelligence. 41(2):606-626. https://doi.org/10.1007/s10489-014-0540-2S606626412Benton J, Coles A, Coles A (2012) Temporal planning with preferences and time-dependent continuous costs. 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    Electrochemical integration of graphene with light absorbing copper-based thin films

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    We present an electrochemical route for the integration of graphene with light sensitive copper-based alloys used in optoelectronic applications. Graphene grown using chemical vapor deposition (CVD) transferred to glass is found to be a robust substrate on which photoconductive Cu_{x}S films of 1-2 um thickness can be deposited. The effect of growth parameters on the morphology and photoconductivity of Cu_{x}S films is presented. Current-voltage characterization and photoconductivity decay experiments are performed with graphene as one contact and silver epoxy as the other

    TCERG1L allelic variation is associated with cisplatin-induced hearing loss in childhood cancer, a PanCareLIFE study.

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    In children with cancer, the heterogeneity in ototoxicity occurrence after similar treatment suggests a role for genetic susceptibility. Using a genome-wide association study (GWAS) approach, we identified a genetic variant in TCERG1L (rs893507) to be associated with hearing loss in 390 non-cranial irradiated, cisplatin-treated children with cancer. These results were replicated in two independent, similarly treated cohorts (n = 192 and 188, respectively) (combined cohort: P = 5.3 × 10-10, OR 3.11, 95% CI 2.2-4.5). Modulating TCERG1L expression in cultured human cells revealed significantly altered cellular responses to cisplatin-induced cytokine secretion and toxicity. These results contribute to insights into the genetic and pathophysiological basis of cisplatin-induced ototoxicity
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