1,323 research outputs found

    An constructive proof for the Umemura polynomials for the third Painlev\'e equation

    Get PDF
    We are concerned with the Umemura polynomials associated with the third Painlev\'e equation. We extend Taneda's method, which was developed for the Yablonskii--Vorob'ev polynomials associated with the second Painlev\'e equation, to give an algebraic proof that the rational functions generated by the nonlinear recurrence relation satisfied by Umemura polynomials are indeed polynomials. Our proof is constructive and gives information about the roots of the Umemura polynomials.Comment: 20 pages, 3 figure

    Renal function, uraemia and early arteriovenous fistula failure

    Get PDF
    Background Guidance varies regarding the optimal timing of arteriovenous fistula (AVF) creation. The aim of this study was to evaluate the association between uraemia, haemodialysis and early AVF failure. Methods Immunoblotting and cell proliferation assays were performed on vascular smooth muscle cells (VSM) cells isolated from long saphenous vein samples to evaluate the cells’ ability to proliferate when stimulated with uraemic (post-dialysis) and hyperuraemic (pre-dialysis) serum. Clinical data was collected prospectively for 569 consecutive radiocephalic (RCF) and brachiocephalic (BCF) fistulae. The primary outcome was AVF failure at 6 weeks. Dialysis status (haemodialysis (HD); pre-dialysis (Pre-D)), eGFR and serum urea were evaluated to determine if they affected early AVF failure. Results Human VSM cells demonstrated increased capacity to proliferate when stimulated with hyperuraemic serum. There was no significant difference in early failure rate of either RCF or BCF depending on dialysis status (pre-D RCF 31.4% (n = 188); pre-D BCF 22.4% (n = 165); HD RCF 29.3% (n = 99); HD BCF 25.9% (n = 116); p = 0.34). There was no difference in mean eGFR between those patients with early AVF failure and those without (11.2+/-0.2 ml/min/1.73 m2 vs. 11.6+/-0.4 ml/min/1.73 m2; p = 0.47). Uraemia was associated with early AVF failure (serum urea: 35.0+/-0.7 mg/dl vs. 26.6+/-0.3 mg/dl (p &lt; 0.001)). Conclusions We present the first in vivo evidence of an association between adverse early AVF outcomes and uraemia. This is supported mechanistically by in vitro work demonstrating a pro-mitogenic effect of hyperuraemic serum. We hypothesise that uraemia-driven upregulation of VSM cell proliferation at the site of surgical insult in contributes to higher early AVF failure rates.</p

    An algebraic proof for the Umemura polynomials for the third Painlevé equation

    Get PDF
    We are concerned with the Umemura polynomials associated with the third Painlev\'e equation. We extend Taneda's method, which was developed for the Yablonskii-Vorob'ev polynomials associated with the second Painlev\'e equation, to give an algebraic proof that the rational functions generated by the nonlinear recurrence relation satisfied by Umemura polynomials are indeed polynomials

    A paper-based simulation model for teaching inguinal hernia anatomy

    Get PDF
    Background: Inguinal hernias remain a challenging area of learning for medical students due to its relatively complex anatomy. Modern curriculum delivery methods are conventionally limited to didactic lectures and demonstration of anatomy intraoperatively. These strategies have limitations; lectures are inherently descriptive and based on 2-dimensional models, while intraoperative teaching is often unstructured and opportunistic. Methods: A paper-based model was developed comprising three overlapping paper panels simulating the anatomical layers of the inguinal canal which can be modified readily to further simulate various hernia pathologies and their surgical repair. These models were incorporated into a timetabled structured learning session for 3rd- and 4th-year medical students. Learners responded to fully anonymised surveys before and after the learning session. Findings: A total of 45 students participated in these sessions over a period of 6 months. Pre-learning session mean ratings for the learners’ confidence in their understanding of the layers of the inguinal canal, identifying indirect and direct inguinal hernias and in naming the contents of the inguinal canal were 2.5, 3.3 and 2.9, while post-learning session mean ratings were 8.0, 9.4 and 8.2, respectively. Paired samples Student’s t-tests for all three questions were statistically significant (p &lt; 0.001). The mean rating for usefulness of the session was 9.6/10. Free comments from students emphasised the models’ usefulness as a visual learning aid. Discussion and Conclusion: Our novel, low-cost paper model was associated with an improvement in learners’ perceived knowledge and understanding of inguinal canal anatomy and pathology

    A Constructive Proof for the Umemura Polynomials of the for the third Painlevé equation

    Get PDF
    We are concerned with the Umemura polynomials associated with rational solutions of the third Painlevé equation. We extend Taneda's method, which was developed for the Yablonskii-Vorob'ev polynomials associated with the second Painlevé equation, to give an algebraic proof that the rational functions generated by the nonlinear recurrence relation which determines the Umemura polynomials are indeed polynomials. Our proof is constructive and gives information about the roots of the Umemura polynomials

    The novel use of Sentimag to localise metallic foreign bodies in soft tissue

    Get PDF
    No abstract available

    Focal Stenosis in Right Upper Lobe Bronchus in a Recurrently Wheezing Child Sequentially Studied by Multidetector-row Spiral Computed Tomography and Scintigraphy

    Get PDF
    Lower respiratory tract infections associated with wheezing are not uncommon in infants and young children. Among the wheezing-associated disorders, allergic etiologies are more commonly encountered than anatomic anomalies. We present a 3-year-old girl with a sudden attack of asthmatic symptoms including dyspnea, cyanosis and diffuse wheezing. Based on a history of choking, and atelectasis in the right upper lobe detected by chest films, flexible tracheobronchoscopy was arranged and incidentally detected a stenotic orifice in the right upper lobe bronchus. Multidetector-row spiral computed tomography and pulmonary scintigraphy subsequently also disclosed the focal stenosis. She suffered from recurrent wheezing, pneumonia and lung atelectasis during 1 year of follow-up. We emphasize the diagnosis, clinical course and management of focal stenosis in the right upper lobe bronchus

    Application of Rat In Situ Single-pass Intestinal Perfusion in the Evaluation of Presystemic Extraction of Indinavir Under Different Perfusion Rates

    Get PDF
    Background/PurposeFirst-pass effect has been an important concern for oral pharmaceuticals. An in vivo system was developed for measuring different concentrations of pharmaceuticals in the portal vein and hepatic vein (via the inferior vena cava) for delineating presystemic metabolism under different perfusion rates by using indinavir as an exemplary agent.MethodsAn in situ single-pass intestinal perfusion technique was modified from previous studies to concomitantly obtain portal and hepatic venous bloods. Portal and hepatic venous samples were simultaneously taken from rats at appropriate time points using the perfusion model of 1 mg/mL indinavir at flow rates of 0.05, 0.1, 0.5 and 1.0 mL/min. The indinavir concentrations were assayed by binary-gradient high-pressure liquid chromatography with UV detection.ResultsThe mean indinavir concentrations in portal vein concentration−time profiles at different perfusion times under various flow rates were all higher than those obtained for hepatic veins. At flow rates of 0.5 and 1.0 mL/min, in particular, the area under the curve (AUC) and maximal concentration (C max) of indinavir absorption were significantly different between portal veins and hepatic veins (p < 0.05), indicating considerable hepatic involvement in the presystemic extraction of indinavir. The system also has potential for use when estimating the hepatic extraction ratio (E H) and hepatic clearance (Cl H).ConclusionThis in vivo approach could provide another useful tool for improving our basic understanding of the absorption kinetics and hepatic metabolism of pharmaceuticals under development and facilitating the clinical application of such

    Crystallographic origin of cycle decay of the high-voltage LiNi\u3csub\u3e0.5\u3c/sub\u3eMn\u3csub\u3e1.5\u3c/sub\u3eO\u3csub\u3e4\u3c/sub\u3e spinel lithium-ion battery electrode

    Get PDF
    High-voltage spinel LiNi0.5Mn1.5O4 (LNMO) is considered a potential high-power-density positive electrode for lithium-ion batteries, however, it suffers from capacity decay after extended charge-discharge cycling, severely hindering commercial application. Capacity fade is thought to occur through the significant volume change of the LNMO electrode occurring on cycling, and in this work we use operando neutron powder diffraction to compare the structural evolution of the LNMO electrode in an as-assembled 18650-type battery containing a Li4Ti5O12 negative electrode with that in an identical battery following 1000 cycles at high-current. We reveal that the capacity reduction in the battery post cycling is directly proportional to the reduction in the maximum change of the LNMO lattice parameter during its evolution. This is correlated to a corresponding reduction in the MnO6 octahedral distortion in the spinel structure in the cycled battery. Further, we find that the rate of lattice evolution, which reflects the rate of lithium insertion and removal, is ∼9 and ∼10% slower in the cycled than in the as-assembled battery during the Ni2+/Ni3+ and Ni3+/Ni4+ transitions, respectively
    • …
    corecore