2,738 research outputs found

    Polarized Photoproduction of Heavy Quarks in Next-to-Leading Order

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    The results of a next-to-leading order calculation of heavy quark production in longitudinally polarized photon-nucleon collisions are presented. At c.m. energy S=10\sqrt{S}=10 GeV, for γ+pc+X\vec \gamma +\vec p \to c+X, cross sections differential in the transverse momentum and rapidity of the charmed quark cc and the corresponding asymmetries are presented; also, as functions of S\sqrt{S}, integrated cross sections, KK-factors and the corresponding asymmetries are given. Errors in the asymmetries are estimated and the possibility to distinguish between three scerarios differing essentially in the polarized gluon distribution is discussed.Comment: 8 pages, 3 figure

    A UK-Wide Survey of Life-Threatening Thyroidectomy Complications

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    Background and Aims. Complications following thyroidectomy can prolong hospital stay and cause significant morbidity particularly for patients treated for benign thyroid conditions. Our aim was to administer a UK-wide survey of thyroid surgery units on frequency and timing of the onset of life-threatening airway complications & correlate to factors that might be associated with them. Methods. A questionnaire including the number of and timing of the onset of life-threatening airway complications, number of thyroidectomy procedures performed per year, surgeon years of experience, the use of difficult airway management protocol, post-operative patient destination, and patient deaths, was sent to 80 UK surgical units. Results. 23/41 hospitals responded reported no postthyroidectomy airway complications. Life-threatening airways complications all occurred within the first 12 hours postoperatively, with 9 cases occurring in the recovery room and in less than 2 hours, 3 cases occurring 2–6 hours, and 3 cases occurring 6 to 12 hours after surgery. Conclusion. The results may support recent publications that advocate thyroidectomy as a less-than-24-hour surgery procedure in selected patients. Further a larger study and standardised protocol are required to establish patients' selection criteria to determine who are likely to develop serious postoperative complication and may require HDU bed

    Design of an asymmetrical rotor for easy assembly and repair of field windings in synchronous machines

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    This paper introduces a new asymmetrical rotor design for easy assembly and repair of field windings in synchronous machines. A new rotor geometry is adopted in order to simplify the manufacture and maintenance process of installing the rotor windings. The asymmetrical rotor design is simulated by the 2-D finite element analysis (FEA), and verified by experimental tests on a 27.5 kVA prototype machine. The proposed topology can drive down the maintenance and repair costs of the machine without impacting on the machine’s electro-magnetic performance. This design will have significant economic implications for machine design and repair industry, especially for mass production markets such as wind turbines and engine-generators

    Modeling DNA Structure, Elasticity and Deformations at the Base-pair Level

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    We present a generic model for DNA at the base-pair level. We use a variant of the Gay-Berne potential to represent the stacking energy between neighboring base-pairs. The sugar-phosphate backbones are taken into account by semi-rigid harmonic springs with a non-zero spring length. The competition of these two interactions and the introduction of a simple geometrical constraint leads to a stacked right-handed B-DNA-like conformation. The mapping of the presented model to the Marko-Siggia and the Stack-of-Plates model enables us to optimize the free model parameters so as to reproduce the experimentally known observables such as persistence lengths, mean and mean squared base-pair step parameters. For the optimized model parameters we measured the critical force where the transition from B- to S-DNA occurs to be approximately 140pN140{pN}. We observe an overstretched S-DNA conformation with highly inclined bases that partially preserves the stacking of successive base-pairs.Comment: 15 pages, 25 figures. submitted to PR

    Two-year real-world outcome data from a single tertiary centre shows reduced ustekinumab persistence in a non-bio-naïve Crohn's disease cohort with penetrating disease, -ostomies and sarcopenia

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    BACKGROUND: Ustekinumab was approved in 2016 for the treatment of moderate-severe Crohn's disease (CD). Clinical trials and real-world studies have suggested ustekinumab to be a safe and effective treatment; however, studies to date infrequently use imaging techniques to predict response to biologics in CD. OBJECTIVES: We assessed the 2-year real-world effectiveness and safety of ustekinumab in a tertiary CD cohort with the use of novel imaging techniques. DESIGN: Retrospective cohort study. METHODS: Retrospective data were collected between 2016 and 2021. Study end points included ustekinumab persistence, biological and/or clinical response and remission at 12, 18 and 24 months. Statistical analysis included demographic and inferential analyses. RESULTS: In all, 131 CD patients [57.3% female, median age of 26.0 (21.0-37.0)] were included. Patients were non-bio naïve, and the majority received ustekinumab as third- or fourth-line treatment. At 24 months, 61.0% (80/131) persisted with ustekinumab [52.7% (69/131) steroid free]. Clinical response was reported in 55.2% (37/67), clinical remission in 85.7% (57/67), biological response in 46.8% (22/47) and biological remission in 31.9% (15/47) of patients at 24 months. The low outcome numbers were attributable to missing data. Improvements in routine disease markers, including C-reactive protein and Harvey-Bradshaw Index, were also reflected in magnetic resonance imaging-derived disease scores. The presence of penetrating CD, an -ostomy and sarcopenia were all predictors of poorer ustekinumab outcomes (p < 0.05). CONCLUSION: Ustekinumab is effective in non-bio-naïve CD patients with non-stricturing, non-penetrating disease with an unremarkable safety profile but may be less effective in those with penetrating disease, -ostomies and sarcopenia

    Intracellular expression of toll-like receptor 4 in neuroblastoma cells and their unresponsiveness to lipopolysaccharide

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    BACKGROUND: Recently it has been reported that, toll-like receptors (TLRs) are expressed on a series of tumor cells, such as colon cancer, breast cancer, prostate cancer, melanoma and lung cancer. Although some cancer cells like melanoma cells are known to respond to lipopolysaccharide (LPS) via TLR4, not all cancer cells are positive for TLR4. There is little information on the expression and function of TLR4 in neuroblastoma cells. In this study, we investigated the expression of TLR4 in human neuroblastoma NB-1 cell line. METHODS: Expression and localization of TLR4 were detected by reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometric analysis, respectively. Activation of nuclear factor (NF)-κB by LPS was detected by degradation of IκB-α and NF-κB luciferase assay. Activation and expression of mitogen-activated protein (MAP) kinase and interferon regulatory factor (IRF)-3 was detected by immunoblot analysis. RESULTS: Human NB-1 neuroblastoma cells expressed intracellular form of TLR4, but not the cell surface form. Further, NB-1 cells express CD14, MD2 and MyD88, which are required for LPS response. However, LPS did not significantly induce NF-κB activation in NB-1 cells although it slightly degraded IκB-α. NB-1 cells expressed no IRF-3, which plays a pivotal role on the MyD88-independent pathway of LPS signaling. Collectively, NB-1 cells are capable to avoid their response to LPS. CONCLUSION: Although human NB-1 neuroblastoma cells possessed all the molecules required for LPS response, they did not respond to LPS. It might be responsible for intracellular expression of TLR4 or lack of IRF-3

    Flood Risk Assessment for Urban Drainage System in a Changing Climate Using Artificial Neural Network

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    Changes in rainfall patterns due to climate change are expected to have negative impact on urban drainage systems, causing increase in flow volumes entering the system. In this paper, two emission scenarios for greenhouse concentration have been used, the high (A1FI) and the low (B1). Each scenario was selected for purpose of assessing the impacts on the drainage system. An artificial neural network downscaling technique was used to obtain local-scale future rainfall from three coarse-scale GCMs. An impact assessment was then carried out using the projected local rainfall and a risk assessment methodology to understand and quantify the potential hazard from surface flooding. The case study is a selected urban drainage catchment in northwestern England. The results show that there will be potential increase in the spilling volume from manholes and surcharge in sewers, which would cause a significant number of properties to be affected by flooding
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