The level of C‐reactive protein in chronic hemodialysis patients: A comparative study between patients with noninfected catheters and arteriovenous fistula in two large Gulf hemodialysis centers

Hemodialysis (HD) patients have greater morbidity and mortality when they have a central venous catheter (CVC) rather than an arteriovenous fistula (AVF) access. Inflammation associated with dialysis catheter use and resultant higher C‐reactive protein (CRP) levels could have an independent adverse effect on patient outcomes. In this prospective study, we investigated whether HD catheters induce inflammation independent of infection. We compared the mean levels of the inflammatory marker (CRP) in 67 patients on maintenance HD using noninfected catheters with 86 HD patients using AVFs at Prince Salman Center for Kidney Diseases, Saudi Arabia (KSA), and Jahra Hospital, Kuwait, who met our inclusion criteria. C‐reactive protein levels were measured every 2 months over a period of 6 months using immunoturbidimetric assay. One hundred fifty‐three patients on maintenance HD for more than 6 months were included in the study, with mean age of 52.19 ± 16.06 years; 66% were males and 34% were females. Serial levels of mean CRP were statistically and significantly higher in group with noninfected catheters (1.33, 1.24, and 1.10 mg/dL) compared to those with AVFs (0.65, 0.59, and 0.68 mg/dL) with P value of 0.000. In our study, we found no relation between CRP level and age, sex, hemoglobin, albumin, calcium, phosphorus, and iPTH level in both groups. Hemodialysis patients with a catheter have a heightened state of inflammation independent of infection, and thus our study supports the avoidance of catheters and a timely conversion to AVFs with catheter removal.     

Alkoxylation of epoxidized polyisoprene by opening of oxirane rings with alcohols

Alkoxylation of epoxidized polyisoprene catalyzed by cerium ammonium nitrate (CAN) was achieved under very mild conditions both in melt and in solution. The cleavage of the epoxidized units with alcohols leads to the formation of alkoxyalcohol units and epoxide rearrangement units in the case of 20 and 38 % epoxidized 1,4‐polyisoprenes. For higher percentage of epoxidation (72 %), cyclization of epoxidized units is observed, which dramatically reduces the alcohol grafting percentage onto the polymer chains. The glass transition temperature increase with the percentage of alkoxylation is attributed to both alkoxy and hydroxyl groups formed after the ring opening of the epoxidized units. However, size‐exclusion chromatography analysis of the modified polymers showed a decrease in the number‐average molecular weight and an increase in the weight‐average molecular weight, which can be interpreted as the degradation and crosslinking of the polymer chains, respectively. Copyright © 2004 Society of Chemical Industry     

Optimum Design of Passive Shunt Filters for Power Distribution Networks

Static, passive, filters present an economic and simple solution to the harmonic distortion at the distribution level and at the same time supply the required reactive power for voltage support and/or power factor correction. Applying these filters to a distribution network, if not properly designed, may have an adverse effect on the network. This paper presents analysis of the effects of using passive harmonic filters in a power distribution networks. The driving point impedance at the node where the filter installed, as a measure of how harmonic currents would produce harmonic voltages, is determined as function of the filter parameters. Hence, effects of filter parameters on the system impedance, parallel resonant frequency and impedance at resonance are illustrated. The effects of using more than one filter are also examined. A method for the optimal design of a passive filter considering the component limits, harmonic distortion limits and parameter tolerances is also presented. The proposed optimization model has proved its effectiveness through application to measurements at a real distribution feeder.     

Sol–gel-deposition of thin TiO2:Eu thermographic phosphor films

A relatively new promising method for surface temperature measurement is the use of thermographic phosphors. For this application, the temperature-dependent luminescence properties of europium (III)-doped anatase (TiO₂:Eu³⁺) thin films were studied. The films were prepared by the sol–gel method using dip coating. The structures and the morphology of the films were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Electron dispersive X-ray spectroscopy (EDX) was used to verify the europium concentration within the films. For using the films as temperature sensors the optical properties are the main concern. Therefore, the emission spectra of the films were measured after ultraviolet laser excitation (355 nm). They indicate that the red characteristic emission (617 nm) of TiO₂:Eu³⁺ due to the ⁵D₀ → ⁷F₂ electric dipole transition is the strongest. The decay time constant of the exponential emission decay under UV excitation with a Nd:YAG laser (355 nm, f = 10 Hz) is strongly temperature dependent in the range from 200 °C up to 400 °C; making it useful for temperature evaluation. The temperature dependence was measured for the emission line at 617 nm; the results demonstrate that anatase doped europium (III) can be used as a thermographic phosphor.     

Allocating transmission loss to loads and generators through complex power flow tracing

This paper presents a new method for complex power flow tracing that can be used for allocating the transmission loss to loads or generators. Two algorithms for upstream tracing (UST) and downstream tracing (DST) of the complex power are introduced. UST algorithm traces the complex power extracted by loads back to source nodes and assigns a fraction of the complex power flow through each line to each load. DST algorithm traces the output of the generators down to the sink nodes determining the contributions of each generator to the complex power flow and losses through each line. While doing so, active- and reactive-power flows as well as complex losses are considered simultaneously, not separately as most of the available methods do. Transmission losses are taken into consideration during power flow tracing. Unbundling line losses are carried out using an equation, which has a physical basis, and considers the coupling between active- and reactive-power flows as well as the cross effects of active and reactive powers on active and reactive losses. The tracing algorithms introduced can be considered direct to a good extent, as there is no need for exhaustive search to determine the flow paths as these are determined in a systematic way during the course of tracing. Results of application of the proposed method are also presented.     

A similarity measure for the negotiation in web services

This paper presents a new negotiation approach integrating a similarity-based metric to measure the client’s satisfaction level by quantifying the correspondence between the features required by the client and the ones proposed by the service. This negotiation process is integrated within an adaptation platform for multimedia presentations supporting different types of terminals. The negotiation and adaptation processes are based on the management of user’s and service’s profiles. We also propose an extension of the SIP protocol to ensure the communication between the client and the server by defining new functionalities.     

First-principle calculations of electronic and ferromagnetic properties of $$\hbox {Al}_{1-x}\hbox {V}_{x}\hbox {Sb}$$

We have used the first-principle calculations of density functional theory within full-potential linearized augmented plane-wave method to investigate the electronic and ferromagnetic properties of \(\hbox {Al}_{1-x}\hbox {V}_{x}\hbox {Sb}\) alloys. The electronic structures of \(\hbox {Al}_{0.25}\hbox {V}_{0.75}\hbox {Sb}, \hbox {Al}_{0.5}\hbox {V}_{0.5}\hbox {Sb}\) and \(\hbox {Al}_{0.75}\hbox {V}_{0.25}\hbox {Sb}\) exhibit a half-metallic ferromagnetic character with spin polarization of 100 %. The total magnetic moment per V atom for each compound is integral Bohr magneton of 2 \(\mu _{\mathrm{B}}\), confirming the half-metallic feature of \(\hbox {Al}_{1-x}\hbox {V}_{x}\hbox {Sb}\). Therefore, these materials are half-metallic ferromagnets useful for possible spintronics applications.     

Preparation of Sb:SnO2 thin films and its effect on opto-electrical properties

The present study focuses on pure and antimony (Sb)-doped tin oxide thin film and its influence on their structural, optical, and electrical properties. Both undoped and Sb-doped SnO₂ thin films have been grown by using simple, inexpensive pyrolysis spray technique. The deposition temperature was optimized to 450 °C. X-ray diffractions pattern have revealed that the films are polycrystalline and have tetragonal rutile-type crystal structure. Undoped SnO₂ films grow along (110) preferred orientation, while the Sb-doped SnO₂ films grow along (200) direction. The size of Sb-doped tin oxide crystals changes from 26.3 to 58.0 nm when dopant concentration is changed from 5 to 25 wt%. The transmission spectra revealed that all the samples are transparent in the visible region, and the optical bandgap varies between 3.92 and 3.98 eV. SEM analysis shows that the surface morphology and grain size are affected by the doping rate. All the films exhibit a high transmittance in the visible region and show a sharp fundamental absorption edge at about 0.38–0.40 nm. The maximum electrical conductivity of 362.5 S/cm was obtained for the film doped with 5 wt% Sb. However, the carrier concentration is increased from 0.708?×?10¹⁸ to 4.058?×?10²⁰ cm³. The electrical study reveals that the films have n-type electrical conductivity and depend on Sb concentration. We observed a decrease in sheet resistance and resistivity with the increase in Sb dopant concentration. For the dopant concentration of 5 wt% of Sb in SnO₂, the Rs and ρ were found minimum with the values of 88.55 (Ω cm^?2) and 2.75 (Ω cm), respectively. We observed an increase in carrier concentration and a decrease in mobility with the addition of Sb up to 25 wt%. The highest figure of merit values 2.5?×?10^–3 Ω^?1 is obtained for the 5wt% Sb, which may be considered potential materials for solar cells' transparent windows.