1,571 research outputs found

    High Mobility Amorphous Polymer-Based 3D Stacked Pseudo Logic Circuits through Precision Printing

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    Direct printing of conjugated polymer thin-film transistors enables the fabrication of deformable devices with low cost, high throughput, and large area. However, a relatively poor device performance of printed devices remains a major obstacle to their application in high-end display backplanes and integrated circuits. In this study, high-performance and highly stackable printed organic transistors is developed, arrays, and circuits using a near-amorphous polymer, indacenodithiophene-co-benzothiadiazole (IDT-BT). The printed devices exhibited high saturation mobility (>1 cm2 V−1 s−1), high on/off ratio (>107), and low subthreshold slope (245 mV dec−1). In addition, 16 × 16 printed IDT-BT arrays achieved 100% fabrication yield, with excellent device-to-device uniformity and low variations of mobility (9.55%) and threshold voltage (4.51%), and good operational and environmental stability (>365 days). Furthermore, five stacked 3D transistors are demonstrated with an excellent 3D uniformity without compromising device performance due to a low required thermal budget for processing amorphous IDT-BT. Finally, a new concept of 3D universal logic gate with high voltage gain (33.91 V/V) and record density (100 printed transistors per cm2) is proposed and fabricated, which is relevant for the commercialization of low-cost printed display backplanes and high-density integrated circuits based on highly processable polymeric semiconductors

    Constraining General Two Higgs Doublet Models by the Evolution of Yukawa Couplings

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    We study how general two Higgs doublet models can be constrained by considering their properties under renormalization group evolution of the Yukawa couplings. We take into account both the appearance of a Landau pole as well as off-diagonal Yukawa couplings leading to flavour changing neutral currents in violation with experimental constraints at the electroweak scale. We find that the latter condition can be used to limit the amount of Z2 symmetry breaking allowed in a given model.Comment: 28 pages, 10 figures, added discussion of evolution from high to low scales, to be published in JHE

    Effect of SiO2 on the Crystallization Behaviors and In-Mold Performance of CaF2-CaO-Al2O3 Slags for Drawing-Ingot-Type Electroslag Remelting

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    The crystallization characteristics of CaF2-CaO-Al2O3 slags with varying amounts of SiO2 were experimentally studied. The effects of slag crystallization behaviors on the horizontal heat transfer and lubrication performance in drawing-ingot-type electroslag remelting (ESR) were also evaluated in terms of as-cast ingots surface quality and drawing-ingot operation. The results show that increasing SiO2 addition from 0 to 6.8 mass pct strongly suppresses the crystallization of ESR type CaF2-CaO-Al2O3 slags. The crystallization temperature of the studied slags decreases with the increase in SiO2 addition. The liquidus temperatures of the slags also show a decreasing trend with increasing SiO2 content. In CaF2-CaO-Al2O3-(SiO2) slags, faceted 11CaO center dot 7Al(2)O(3)center dot CaF2 crystals precipitate first during continuous cooling of the slag melts, followed by the formation of CaF2 at lower temperatures. 11CaO center dot 7Al(2)O(3)center dot CaF2 was confirmed to be the dominant crystalline phase in the studied slags. CaF2-CaO-Al2O3 slags with a small amount of SiO2 addition are favorable for providing sound lubrication and horizontal heat transfer in mold for drawing-ingot-type ESR, which consequently bring the improvement in the surface quality of ESR ingot and drawing-ingot operating practice as demonstrated by plant trials.open11108sciescopu

    The Patients Assessment Chronic Illness Care (PACIC) questionnaire in The Netherlands: a validation study in rural general practice

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    BACKGROUND: Many patients with chronic illness receive health care in primary care settings, so a challenge is to provide well-structured chronic care in these settings. Our aim was to develop and test a Dutch version of the PACIC questionnaire, a measure for patient reported structured chronic care. METHODS: Observational study in 165 patients with diabetes or COPD from four general practices (72% response rate). Patients completed a written questionnaire, which included instruments for assessing chronic illness care (PACIC), evaluations of general practice (Europep), enablement (PEI), and individual characteristics. RESULTS: The patients had a mean age of 68.0 years and 47% comprised of women. Twenty-two to 35% of responding patients did not provide answers to specific items in the PACIC. In 11 items the lowest answering category was used by 30% or more of the responders and in 6 items the highest answering category was used by this number of responders. Principal factor analysis identified the previously defined five domains reasonably well. Cronbach's alpha per domain varied from 0.71 to 0.83, and the intraclass coefficient from 0.66 to 0.91. Diabetes patients reported higher presence of structured chronic care for 14 out of the 20 PACIC items. The effect of patient evaluations of general practice on the PACIC score was positive (b = 0.72, p < 0.004), but the effect of patient enablement on the PACIC score was negative (b = -1.13, p < 0.000). CONCLUSION: A translated and validated Dutch version of the PACIC questionnaire is now available. Further research on its validity is recommended

    In situ epitaxial MgB2 thin films for superconducting electronics

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    A thin film technology compatible with multilayer device fabrication is critical for exploring the potential of the 39-K superconductor magnesium diboride for superconducting electronics. Using a Hybrid Physical-Chemical Vapor Deposition (HPCVD) process, it is shown that the high Mg vapor pressure necessary to keep the MgB2_2 phase thermodynamically stable can be achieved for the {\it in situ} growth of MgB2_2 thin films. The films grow epitaxially on (0001) sapphire and (0001) 4H-SiC substrates and show a bulk-like TcT_c of 39 K, a JcJ_c(4.2K) of 1.2×1071.2 \times 10^7 A/cm2^2 in zero field, and a Hc2(0)H_{c2}(0) of 29.2 T in parallel magnetic field. The surface is smooth with a root-mean-square roughness of 2.5 nm for MgB2_2 films on SiC. This deposition method opens tremendous opportunities for superconducting electronics using MgB2_2

    Abdominal functional electrical stimulation to improve respiratory function after spinal cord injury: a systematic review and meta-analysis

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    Objectives: Abdominal functional electrical stimulation (abdominal FES) is the application of a train of electrical pulses to the abdominal muscles, causing them to contract. Abdominal FES has been used as a neuroprosthesis to acutely augment respiratory function and as a rehabilitation tool to achieve a chronic increase in respiratory function after abdominal FES training, primarily focusing on patients with spinal cord injury (SCI). This study aimed to review the evidence surrounding the use of abdominal FES to improve respiratory function in both an acute and chronic manner after SCI. Settings: A systematic search was performed on PubMed, with studies included if they applied abdominal FES to improve respiratory function in patients with SCI. Methods: Fourteen studies met the inclusion criteria (10 acute and 4 chronic). Low participant numbers and heterogeneity across studies reduced the power of the meta-analysis. Despite this, abdominal FES was found to cause a significant acute improvement in cough peak flow, whereas forced exhaled volume in 1 s approached significance. A significant chronic increase in unassisted vital capacity, forced vital capacity and peak expiratory flow was found after abdominal FES training compared with baseline. Conclusions: This systematic review suggests that abdominal FES is an effective technique for improving respiratory function in both an acute and chronic manner after SCI. However, further randomised controlled trials, with larger participant numbers and standardised protocols, are needed to fully establish the clinical efficacy of this technique

    Language and sociability: insights from Williams syndrome

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    One of the most compelling features of Williams syndrome (WS) is the widely reported excessive sociability, accompanied by a relative proficiency in expressive language, which stands in stark contrast with significant intellectual and nonverbal impairments. It has been proposed that the unique language skills observed in WS are implicated in the strong drive to interact and communicate with others, which has been widely documented in WS. Nevertheless, this proposition has yet to be empirically examined. The present study aimed at investigating the relationship between a brain index of language processing and judgments of approachability of faces, as a proxy for sociability, in individuals with WS as contrasted to typical controls. Results revealed a significant and substantial association between the two in the WS, but not in the control group, supporting the hitherto untested notion that language use in WS might be uniquely related to their excessive social drive

    Metastatic skull tumors: MRI features and a new conventional classification

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    Skull metastases are malignant bone tumors which are increasing in incidence. The objectives of this study were to characterize the MR imaging features, locations, and extent of metastatic skull tumors to determine the frequency of the symptomatic disease, and to assess patient outcomes. Between September 2002 and March 2008, 175 patients undergoing routine head MR imaging were found to have metastatic skull tumors. Contrast-enhanced study with fat suppression was used in some cases when required. Classification of metastases was simplified to three yes/no questions: first, with regard to location (either in the calvarium or in the cranial base); second, with regard to distribution within the plane of the cranial bone (either “circumscribed” meaning clearly demarcated and confined to one bone, or “diffuse” and likely to spread across a suture to another bone); and third, with regard to invasion (“intraosseous” in cranial bones only, or “invasive” spreading from the skull, either out into the scalp or inward to the dura and perhaps further in). Primary sites were breast cancer (55%), lung cancer (14%), prostate cancer (6%), malignant lymphoma (5%), and others (20%). The mean time from primary diagnosis to skull metastasis diagnosis was 71 months for cases of breast cancer, 26 months for prostate cancer, 9 months for lung cancer, and 4 months for malignant lymphoma. Calvarial circumscribed intraosseous metastases were found most frequently (27%). The patients were mainly asymptomatic. However, some patients suffered from local pain or cranial nerve palsies that harmed their quality of life. Treatment, mainly for symptomatic cases, was by local or whole-skull irradiation. Metastatic skull tumors are not rare, and most are calvarial circumscribed intraosseous tumors. MR images contribute to understanding their type, location, and multiplicity, and their relationship to the brain, cranial nerves, and dural sinuses. Radiation therapy improved the QOL of patients with neurological symptoms

    Ensemble Place Codes in Hippocampus: CA1, CA3, and Dentate Gyrus Place Cells Have Multiple Place Fields in Large Environments

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    Previously we reported that the hippocampus place code must be an ensemble code because place cells in the CA1 region of hippocampus have multiple place fields in a more natural, larger-than-standard enclosure with stairs that permitted movements in 3-D. Here, we further investigated the nature of hippocampal place codes by characterizing the spatial firing properties of place cells in the CA1, CA3, and dentate gyrus (DG) hippocampal subdivisions as rats foraged in a standard 76-cm cylinder as well as a larger-than-standard box (1.8 m×1.4 m) that did not have stairs or any internal structure to permit movements in 3-D. The rats were trained to forage continuously for 1 hour using computer-controlled food delivery. We confirmed that most place cells have single place fields in the standard cylinder and that the positional firing pattern remapped between the cylinder and the large enclosure. Importantly, place cells in the CA1, CA3 and DG areas all characteristically had multiple place fields that were irregularly spaced, as we had reported previously for CA1. We conclude that multiple place fields are a fundamental characteristic of hippocampal place cells that simplifies to a single field in sufficiently small spaces. An ensemble place code is compatible with these observations, which contradict any dedicated coding scheme
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