250 research outputs found
Practice Patterns Of Clinicians: Assessment Of Malnutrition In Ckd Dialysis And Interventions
With limited information on the practice patterns regarding clinician identification of malnutrition and the use of nutritional interventions in malnourished CKD-5 dialysis patients, a market research survey was conducted by NKF sponsored by Pentec Health to evaluate this amongst renal clinicians. For dialysis patients, results for the top four assessment markers were: decreased appetite; albumin level; decrease in dry weight, quality of life. Most commonly recommended oral supplements (OS) were nutritionally complete renal, diabetic and standard products with most common barriers: out of pocket cost; patient resistance; and reimbursement issues. Nutrition support and food during dialysis responses for outpatients in table below:Nutrition Intervention% of clinicians who would recommendBarriers to Use (Top 3 )Tube Feeding28.0 %Not available at unit; patient resistance; family resistanceIntradialytic Parenteral Nutrition (IDPN)48.7 %Reimbursement ; not available at unit; MD resistanceIntraperitoneal Nutrition (IPN)22.0 %Not available at unit; reimbursement; MD resistanceTotal Parenteral Nutrition (TPN)16.9 %Not available at unit; reimbursement, MD resistanceFood During Hemodialysis83.3 % OS 63.3% FoodDrop in blood pressure, risk of aspiration; hygieneFindings: A clinician gap seems to exist around nutrition support interventions in CKD-5 dialysis patients. Meal provision during dialysis could be expanded. These interventions may improve the nutritional status of dialysis patients
Robustness to Algorithmic Singularities and Sensitivity in Computational Kinematics
A robust approach to computational kinematics intended to cope with algorithmic singularities is introduced in this article. The approach is based on the reduction of the original system of equations to a subsystem of bivariate equations, as opposed to the multivariate polynomial reduction leading to the characteristic univariate polynomial. The effectiveness of the approach is illustrated for the exact function-generation synthesis of planar, spherical, and spatial four-bar linkages. Some numerical examples are provided for the case of the spherical four-bar function generator with six precision points to show the benefits of the proposed method with respect to methods reported in the literature.The first author acknowledges the support of Universidad Politecnica de Valencia, research project PAID-00-09. The second author acknowledges the support of McGill University by means of a James McGill Professorship.Gracia Calandin, LI.; Angeles, J. (2011). Robustness to Algorithmic Singularities and Sensitivity in Computational Kinematics. Proceedings of the Institution of Mechanical Engineers part C - Journal of Mechanical Engineering Science. 225(4):987-999. doi:10.1243/09544062JMES2464S9879992254Raghavan, M., & Roth, B. (1993). Inverse Kinematics of the General 6R Manipulator and Related Linkages. Journal of Mechanical Design, 115(3), 502-508. doi:10.1115/1.2919218Lee, H. Y., Woernle, C., & Hiller, M. (1991). A Complete Solution for the Inverse Kinematic Problem of the General 6R Robot Manipulator. Journal of Mechanical Design, 113(4), 481-486. doi:10.1115/1.2912808Innocenti, C., & Parenti-Castelli, V. (1993). Echelon form solution of direct kinematics for the general fully-parallel spherical wrist. Mechanism and Machine Theory, 28(4), 553-561. doi:10.1016/0094-114x(93)90035-tGosselin, C. M., Sefrioui, J., & Richard, M. J. (1994). On the Direct Kinematics of Spherical Three-Degree-of-Freedom Parallel Manipulators of General Architecture. Journal of Mechanical Design, 116(2), 594-598. doi:10.1115/1.2919419Alizade, R. I., & Kilit, Ă–. (2005). Analytical synthesis of function generating spherical four-bar mechanism for the five precision points. Mechanism and Machine Theory, 40(7), 863-878. doi:10.1016/j.mechmachtheory.2004.12.010Cervantes-Sánchez, J. J., Gracia, L., Rico-MartĂnez, J. M., MedellĂn-Castillo, H. I., & González-Galván, E. J. (2009). A novel and efficient kinematic synthesis approach of the spherical 4R function generator for five and six precision points. Mechanism and Machine Theory, 44(11), 2020-2037. doi:10.1016/j.mechmachtheory.2009.05.006Angeles, J. (2007). Fundamentals of Robotic Mechanical Systems. Mechanical Engineering Series. doi:10.1007/978-0-387-34580-2Bai, S., Hansen, M. R., & Angeles, J. (2009). A robust forward-displacement analysis of spherical parallel robots. Mechanism and Machine Theory, 44(12), 2204-2216. doi:10.1016/j.mechmachtheory.2009.07.005Sommese, A. J., & Wampler, C. W. (2005). The Numerical Solution of Systems of Polynomials Arising in Engineering and Science. doi:10.1142/5763Forsythe, G. E. (1970). Pitfalls in Computation, or why a Math Book isn’t Enough. The American Mathematical Monthly, 77(9), 931. doi:10.2307/2318109Angeles, J., Hommel, G., & Kovács, P. (Eds.). (1993). Computational Kinematics. Solid Mechanics and Its Applications. doi:10.1007/978-94-015-8192-9Yang, A. T., & Freudenstein, F. (1964). Application of Dual-Number Quaternion Algebra to the Analysis of Spatial Mechanisms. Journal of Applied Mechanics, 31(2), 300-308. doi:10.1115/1.3629601Gupta, K. C., & Beloiu, A. S. (1998). Branch and circuit defect elimination in spherical four-bar linkages. Mechanism and Machine Theory, 33(5), 491-504. doi:10.1016/s0094-114x(97)00078-
Leadless Cardiac Pacemakers Back to the Future
AbstractDespite significant advances in battery longevity, lead performance, and programming features since the first implanted permanent pacemaker was developed, the basic design of cardiac pacemakers has remained relatively unchanged over the past 50 years. Because of inherent limitations in their design, conventional (transvenous) pacemakers are prone to multiple potential short- and long-term complications. Accordingly, there has been intense interest in a system able to provide the symptomatic and potentially lifesaving therapies of cardiac pacemakers while mitigating many of the risks associated with their weakest link—the transvenous lead. Leadless cardiac pacing represents the future of cardiac pacing systems, similar to the transition that occurred from the use of epicardial pacing systems to the familiar transvenous systems of today. This review summarizes the current evidence and potential benefits of leadless pacing systems, which are either commercially available (in Europe) or under clinical investigation
Continuity and Stability of Partial Entropic Sums
Extensions of Fannes' inequality with partial sums of the Tsallis entropy are
obtained for both the classical and quantum cases. The definition of kth
partial sum under the prescribed order of terms is given. Basic properties of
introduced entropic measures and some applications are discussed. The derived
estimates provide a complete characterization of the continuity and stability
properties in the refined scale. The results are also reformulated in terms of
Uhlmann's partial fidelities.Comment: 9 pages, no figures. Some explanatory and technical improvements are
made. The bibliography is extended. Detected errors and typos are correcte
Structural basis for chemokine recognition and activation of a viral G protein-coupled receptor
Chemokines are small proteins that function as immune modulators through activation of chemokine G protein–coupled receptors (GPCRs). Several viruses also encode chemokines and chemokine receptors to subvert the host immune response. How protein ligands activate GPCRs remains unknown. We report the crystal structure at 2.9 angstrom resolution of the human cytomegalovirus GPCR US28 in complex with the chemokine domain of human CX3CL1 (fractalkine). The globular body of CX3CL1 is perched on top of the US28 extracellular vestibule, whereas its amino terminus projects into the central core of US28. The transmembrane helices of US28 adopt an active-state–like conformation. Atomic-level simulations suggest that the agonist-independent activity of US28 may be due to an amino acid network evolved in the viral GPCR to destabilize the receptor’s inactive state.Swiss National Science FoundationNational Institutes of Health (U.S.) (Pioneer Award)Virginia and D.K. Ludwig Fund for Cancer Researc
Dynamics of Simple Balancing Models with State Dependent Switching Control
Time-delayed control in a balancing problem may be a nonsmooth function for a
variety of reasons. In this paper we study a simple model of the control of an
inverted pendulum by either a connected movable cart or an applied torque for
which the control is turned off when the pendulum is located within certain
regions of phase space. Without applying a small angle approximation for
deviations about the vertical position, we see structurally stable periodic
orbits which may be attracting or repelling. Due to the nonsmooth nature of the
control, these periodic orbits are born in various discontinuity-induced
bifurcations. Also we show that a coincidence of switching events can produce
complicated periodic and aperiodic solutions.Comment: 36 pages, 12 figure
Full-scale testing of laser clad railway track; case study - testing for wear, bend fatigue and insulated block joint lipping integrity
This paper reports on a series of tests which were carried out on full-scale sections of rail that
had been treated by laser cladding aiming to create a layer (~1-2mm) of high performance
material on the rail head. Experiments were designed to measure wear, lipping of insulated
block joints (IBJs) and bending fatigue of clad samples. The wear rate of the clad samples was
between 78- 89% lower than that of the standard R260 reference sample. Cladding of either
side of an insulated block joint greatly improves its lipping resistance and allows it to withstand
approximately 3 times the energy input into the contact compared to a standard un-clad IBJ. A
section of rail clad with martensitic stainless steel was subject to bend fatigue testing and ran
out to 5,000,000 cycles at a stress range of 350 MPa matching the performance of an unclad
R260 rail. Although there is no standard for the bend testing of laser clad rail this performance
exceeds the performance requirements of the NR/SP/TRK111 standard which governs the bend
testing of flash but welded rail
Polarisation of equine pregnancy outcome associated with a maternal MHC class I allele: preliminary evidence
Identification of risk factors which are associated with severe clinical signs can assist in the management of disease outbreaks and indicate future research areas. Pregnancy loss during late gestation in the mare compromises welfare, reduces fecundity and has financial implications for horse owners. This retrospective study focussed on the identification of risk factors associated with pregnancy loss among 46 Thoroughbred mares on a single British stud farm, with some but not all losses involving equid herpesvirus-1 (EHV-1) infection. In a sub-group of 30 mares, association between pregnancy loss and the presence of five common Thoroughbred horse haplotypes of the equine Major Histocompatibility Complex (MHC) was assessed. This involved development of sequence specific, reverse transcriptase polymerase chain reactions and in several mares, measurement of cytotoxic T lymphocyte activity. Of the 46 mares, 10 suffered late gestation pregnancy loss or neonatal foal death, five of which were EHV-1 positive. Maternal factors including age, parity, number of EHV-1 specific vaccinations and the number of days between final vaccination and foaling or abortion were not significantly associated with pregnancy loss. In contrast, a statistically significant association between the presence of the MHC class I B2 allele and pregnancy loss was identified, regardless of the fetus / foal’s EHV-1 status (p=0.002). In conclusion, this study demonstrated a significantly positive association between pregnancy loss in Thoroughbred mares and a specific MHC class I allele in the mother. This association requires independent validation and further investigation of the mechanism by which the mare’s genetic background contributes to pregnancy outcome
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