The Impact of Intraluminal Vancomycin Adminstration on Prevention of Hemodialysis Catheter-Related Infections

Abstract: Introduction: Percutaneously inserted double-lumen central venous hemodialysis catheters provide the nephrologist with an excellent temporary access for an immediate hemodialysis treatment and preserve the peripheral veins for the future creation of a permanent arteriovenous vascular access. Unfortunately catheter-related infections are usually common. In this study, the impact of intra luminal vancomycin administration on catheter-related infections in a group of hemodialyzed patients has been investigated. Method: A total of 100 patients with renal failure requiring hemodialysis by way of double-lumen central venous catheters inserted into the internal jugular or subclavian vein in 6 months period, were randomly divided into two groups of receiving a single intravenous dose of 1000 mg of vancomycin during catheter insertion and no antibiotics. The rate of infection, in situ duration of the initial catheter, number of dialysis sessions per week, site of catheter, length of the catheter which was outside of the skin, catheter tip cultures and the presence of systemic infections related to the catheter, were recorded for every patient. The study period was terminated when the initial catheter was changed or removed for any reason. Results: Catheter-related infection was observed in 6 patients: 2 patients (4%) in the first group who received vancomycin and 4 patients (8%) in the second group who received no antibiotic (P= 0.05). In regard to infection, 33.3% of the infections occurred in the first week after catheter insertion, 16.7% in the second week and 50% in the third week and there was no association between the duration of catheter fixation and infection (P= 0.7). The type of the catheter (jugular or subclavian) and the length of the catheter which was outside of the skin had not any effect on the catheter infection (P= 0.5 and P= 0.6 respectively). In all cases infection was due to staphylococcus. Conclusion: It can be concluded that in uremic patients, a single intravenous dose of vancomycin during the insertion of a double-lumen hemodialysis catheter into the internal jugular or subclavian vein has no effect on prevention of catheter-related infections. Keywords: Vascular Access, Vancomycin, Hemodialysi

Unusual condensation of ethylene glycol with coordinated 1,10-phenanthroline-5,6-dione in [Ru(phen-dione)2Cl2] and its cyclometallated complex, [Ru(phpy-κ2 N,C2’)(phen-diox)2](PF6)

A novel cyclometallated Ru(II) derivative of 1,10-phenanthroline-5,6-dione (phen-dione), [Ru(phpyj2N, C20)(phen-diox)2](PF6), where phpy-j2N,C20 is 2-phenylpyridine and phen-diox is 2,3-dihydro- 4a,12b-(epoxyethanooxy)[1,4]dioxino[2,3-f][1,10]phenanthroline, has been prepared by the metal-assisted effect of [Ru(phen-dione)2Cl2] via an unusual condensation of the coordinated phen-dione ligand with ethylene glycol which led to the formation of [Ru(phen-diox)2Cl2]. The condensation reaction could not proceed in the absence of [Ru(phen-dione)2Cl2]. DFT calculations showed that the energy of the LUMO of [Ru(phen-dione)2Cl2] is about 12.430 kcal/mol lower than that of the uncoordinated phen-dione ligand. The cyclometallated complex has been characterized by elemental analysis, spectroscopic and spectroelectrochemical (SEC) techniques, cyclic voltammetry and X-ray crystallography. X-ray analysis of the complex shows an elongation of one of the five Ru–N bonds due to a strong trans effect of the carbanionic ligand. The electrochemical data of the complex demonstrate a strong r-donating character of the anionic phenylpyridine ligand. UV–vis spectroelectrochemical studies of the complex in acetonitrile show a reversible redox behavior, evaluated by the maintenance of isosbestic points in the UV–vis spectrum for both forward oxidation and reverse reduction processes. The complex is very weakly emissive at room temperature in degassed acetonitrile with kem = 546 nm and /em = 0.02

Immobilization of gold nanoparticles on folate-conjugated dendritic mesoporous silica-coated reduced graphene oxide nanosheets: a new nanoplatform for curcumin pH-controlled and targeted delivery.

A nanocarrier for curcumin targeted delivery and cell imaging was prepared by immobilization of gold NPs on the folic acid-modified dendritic mesoporous silica-coated reduced graphene oxide nanosheets.</p

Mathematical modeling of the twin roll casting process for AZ31 magnesium alloy - Effect of set-back distance

A 2-D coupled thermal-fluid-stress model was developed and used to simulate the twin roll casting (TRC) of an AZ31 magnesium alloy using the commercial software package, ALSIM. The model was used to predict the fluid flow, temperature distribution and mechanical behavior of AZ31 magnesium alloy in the roll bite. An important parameter in controlling the TRC process is the set-back distance; the distance between the nozzle entry to the kissing point of the rolls. There are two approaches to increase the set-back: 1) increasing the entry thickness and 2) decreasing the final strip thickness. In this study the effect of set-back distance and casting speed on the thermo-mechanical behavior of the strip during TRC has been studied. The thermo-mechanical behavior of the strip has a significant effect on the final quality as defect formation depends on such behavior

Indentation-derived creep response of cast and laser powder bed fused AlSi10Mg alloy: Air temperature

Compared with time-consuming conventional uniaxial tensile/compressive creep experiments, depth-sensing indentation testing is considered a reliable, and convenient testing technique to assess the time-dependent plastic deformation of materials in a reasonable time scale. In the present study, we report the ambient (room) temperature indentation creep properties of additively manufactured (i.e., laser-powder bed fused) and cast AlSi10Mg alloy at as-fabricated and different post-fabrication heat treatment states. The indentation creep testing parameters (i.e., dwell time, peak indentation load, and indenter shape) were optimized to adequately represent the creep response (time-displacement) variations for different material conditions. To this end, dual-stage, constant loading rate followed by constant-load holding, pyramidal indentation experiments were performed at a loading rate of 10 mN/s, a peak load of 200 mN, and a dwell time of 400 s. Besides, electron backscattered diffraction was performed to evaluate the manufacturing process (selective laser melted versus cast)/ post-fabrication heat treatment/ texture/ creep properties relationships for the studied AlSi10Mg alloy. Also, the indentation hardness, indentation strain rate sensitivity, indentation creep exponent, and activation volume were analyzed to study and confirm the mechanism of indentation creep. The calculated high values of creep stress exponents (i.e., \u3e10) are attributed to dislocation-reinforcing particle interaction as the controlling mechanism of the creep which agrees with this assumption that AlSi10Mg is indeed an in-situ metal matrix composite with eutectic silicon as the reinforcing particles

Cis,cis-μ-2,3,5,6-Tetra-2-pyridylpyrazine-κ3N 1,N2,N6:κ3N3,N 4,N5-bis[dichloro(dimethyl sulfoxide-κS) ruthenium(II)] dihydrate acetone disolvate

The reaction of 2,3,5,6-tetra-2-pyridylpyrazine (tppz) with dichlorotetrakis(dimethyl sulfoxide)ruthenium(II) in dimethyl sulfoxide (DMSO) yielded the title centrosymmetric dinuclear complex, [Ru2Cl 4(C24H16N6)(C3H 6OS)2]·2C2H6OS·2H 2O or cis,cis-[{Ru(DMSO)Cl2}2(μ-tppz)] ·2Me2CO·2H2O. Each ruthenium ion is in a distorted octahedral coordination in which the chloro ligands are cis to each other and DMSO is coordinated through sulfur. The asymmetric unit contains half of two independent molecules

The role of titanium on the microstructure and mechanical properties of additively manufactured C300 maraging steels

In this study, C300 metal powders containing two different Ti contents (0.72 and 1.17 wt%) were used to additively manufacture maraging steel samples in both horizontal and vertical directions via laser powder bed fusion (LPBF) technique. The effect of Ti addition on the microstructural and mechanical properties of the additively manufactured (AM) maraging steels was investigated using scanning, transmission electron microscopies (SEM, TEM), and electron backscatter diffraction (EBSD) along with uniaxial tensile and hardness testing procedures. Besides, X-ray diffraction (XRD) technique was employed to identify various phases formed during the LPBF process. The results showed that the horizontally printed Ti-rich samples exhibited higher retained austenite (γ) phase and superior values of hardness and tensile strength, while those ones vertically prepared showed an excellent ductility that could bring benefits in high-cycle fatigue applications. The TEM observations confirmed the presence of CoNi precipitates as well as high dislocation densities in the horizontal high Ti content samples, which are associated with higher strain hardening and tensile strength

Dinuclear copper(II) chloro complex of the ligand 2,3,5,6-tetra(2-pyridyl) pyrazine

Crystallographic and magnetic studies have been performed on the complex, [{CuCl}2(μ-tppz)][PF6]2, where tppz is 2,3,5,6-tetra-2-pyridinylpyrazine. The crystal structure revealed an infinite, ionic chain wherein Cu(II) ions are respectively above and below the plane of the pyrazine moiety of the bridging tppz ligand with the pyridine moieties moving out of the pyrazine plane in order to coordinate to Cu(II). Each chloride ligand bonds equatorially to Cu(II) in a [{CuCl}2(μ-tppz)] 2+ ion and axially to a neighboring [{CuCl}2(μ-tppz)] 2+ ion so as to form a one-dimensional chain in the solid state. The temperature-dependent magnetic susceptibilitity could be satisfactorily fitted by using a modified Bleaney-Bowers expression (for H = -JSa • Sb J = -5.6 cm-1 and g = 2.16) where the exchange interaction is suggested to involve the orbitals of the tppz ligand