Relation between Access-Related Infection and Preinfection Serum Albumin Concentration in Patients on Chronic Hemodialysis

Background: Hemodialysis (HD) access‐related infection is a major cause of morbidity and mortality in HD patients. We tested whether hypoalbuminemia is a risk factor for HD access infection and whether mortality of HD catheter infection is affected by removal of the infected catheter. Methods: We analyzed the records of 87 patients on chronic HD who were hospitalized for HD access‐related infection. We obtained data on age, sex, preinfection serum albumin level, comorbidities, complications, infecting organism, type of infection, mode of management, and mortality. We compared preinfection serum albumin levels in 79 patients with HD access infection with the serum albumin levels of 198 control patients on chronic HD without HD access infection admitted to the hospital during the same time for other reasons. In the HD catheter infection subgroup, we compared mortalities between patients treated with catheter removal plus antibiotics as the primary mode of management and those treated initially with antibiotics alone. Results: Preadmission serum albumin level was lower in the HD access infection group (2.4 ± 0.6 g/dL) than in the control group (3.2 ± 0.6 g/dL, P < 0.0001). Logistic regression identified preadmission serum albumin level as a strong independent predictor of HD access infection. In a logistic regression model, with age, sex, HIV status, diabetes, and type of HD vascular access (excluding arterovenous fistula) as the covariates, the odds ratio of HD access infection was 9.8 (95% confidence interval [CI] 4.9–19.7) for a serum albumin level ≤ 3.0 g/dL (P < 0.0001), 10.4 (95% CI 4.97–21.6) for a serum albumin level ≤ 2.5 g/dL (P < 0.0001), and 28.0 (95% CI 5.8–135.9) for a serum albumin level ≤ 2.0 g/dL (P < 0.0001). Case mortality was 25.0% (4/16) in patients with tunneled HD catheter infection initially treated with antibiotics alone and 2.8% (2/71) in those treated with catheter removal plus antibiotics at the time of presentation (P = 0.0096). Conclusion: Hypoalbuminemia is associated with increased risk of HD access infection. Treatment of HD access infection with antibiotics alone is associated with increased risk of death.     

Hydrophilic Nanotube Supported Graphene–Water Dispersible Carbon Superstructure with Excellent Conductivity

In this work, it is shown that the hydrophilic functionalized multiwall carbon nanotubes (MWCNs) can stabilize a large amount of pristine graphene nanosheets in pure water without the assistance of surfactants, ionic liquids, or hydrophilic polymers. Role of stabilizer is conveyed by highly hydrophilic carbon nanotubes, functionalized by dihydroxy phenyl groups, affording a stable dispersion at concentrations as high as 15 mg mL^?1. Such multidimensional (2D/1D) graphene/MWCN hybrid is found to be dispersible also in other polar organic solvents such as ethanol, isopropanol, N,N‐dimethylformamide, ethylene glycol, and their mixtures. High‐resolution transmission microscopy and atomic force microscopy (AFM) including a liquid mode AFM manifest several types of interaction including trapping of multiwalled carbon nanotubes between the graphene sheets or the modification of graphene edges. Molecular dynamic simulations show that formation of an assembly is kinetically controlled. Importantly, the hybrid can be deposited on the paper by drop casting or dispersed in water‐soluble polymers resulting in record values of electrical conductivity (sheet resistance up to R_s ≈ 25 Ω sq^?1 for free hybrid material and R_s ≈ 1300 Ω sq^?1 for a polyvinilalcohol/hybrid composite film). Thus, these novel water dispersible carbon superstructures reveal a high application potential as conductive inks for inkjet printing or as highly conductive polymers.     

Interactions of Skin with Gold Nanoparticles of Different Surface Charge,Shape, and Functionality

The interactions between skin and colloidal gold nanoparticles of different physicochemical characteristics are investigated. By systematically varying the charge, shape, and functionality of gold nanoparticles, the nanoparticle penetration through the different skin layers is assessed. The penetration is evaluated both qualitatively and quantitatively using a variety of complementary techniques. Inductively coupled plasma optical emission spectrometry (ICP‐OES) is used to quantify the total number of particles which penetrate the skin structure. Transmission electron microscopy (TEM) and two photon photoluminescence microscopy (TPPL) on skin cross sections provide a direct visualization of nanoparticle migration within the different skin substructures. These studies reveal that gold nanoparticles functionalized with cell penetrating peptides (CPPs) TAT and R₇ are found in the skin in larger quantities than polyethylene glycol‐functionalized nanoparticles, and are able to enter deep into the skin structure. The systematic studies presented in this work may be of strong interest for developments in transdermal administration of drugs and therapy.     

A scalable advanced RF IC design‐oriented MOSFET model

This article presents a validation of the EKV3 MOSFET compact model dedicated to the design of analogue/RF ICs using advanced CMOS technology. The EKV3 model is compared with DC, CV and RF measurements up to 20 GHz of a 110 nm CMOS technology. The scaling behaviour over a large range of channel lengths and bias conditions is presented. Long‐channel devices show significant non‐quasi static effects while in short‐channel devices the parasitics modelling is critical. This is illustrated with Y‐parameters and f_t vs. I_D in NMOS and PMOS devices, showing good overall RF modelling abilities of the EKV3 MOSFET model. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.     

Laboratory-made cement-bonded OSB with negligible swelling: fact or fantasy?

The purpose of this paper was to evaluate the dimensional stability of cement-bonded oriented strand boards produced from fir strands, which have previously been chemically modified at a weight gain of 10.4%, after 30 min reaction with acetic anhydride. The strands were used to form laboratory boards, which were tested in accordance with EN standards. Boards made from these acetylated strands exhibited negligible thickness swelling even after one month of immersion in water.     

Moisture adsorption isotherms of two esterified Greek hardwoods

Two Greek hardwoods (Ulmus montana and Acer pseudoplatanus), were esterified with acetic and maleic anhydride and studied for moisture adsorption behaviour. The sorption isotherms for untreated and chemically modified wood were analysed using the Hailwood-Horrobin model. The experimental analysis of the sorption isotherms showed that esterification affects both total, polymolecular and monomolecular sorption. Acetic anhydride treatment was found more effective in reducing the hygroscopicity of wood compared to maleic anhydride treatment at comparable weight percentage gain, reflecting probably the strong ester bonds between acetic anhydride and wood. Identical e.m.c values were attained in both types of sorption for maple and elm wood, at comparable weight percentage gain, not only for the unmodified samples but for the modified ones as well.     

Pyridine-catalyst acetylation of pine wood: influence of mature sapwood vs juvenile wood

The aim of this study was to evaluate the effect that chemical modification by means of acetylation may have on juvenile vs mature pine sapwood. The results indicated that juvenile wood had clearly an adverse effect on acetylation; the magnitude of the reduction in WPG in juvenile wood was approximately 50% less than that of mature sapwood. The difference in the chemistry of the pyridine-catalysed acetylation vs the non-catalysed acetylation is thought to be responsible for this behaviour.     

Microstructural Evolution during Transient Plastic Phase Processing of Titanium Carbide-Titanium Boride Composites

Transient plastic phase processing is a form of reactive hot pressing for fabricating fully dense ceramic-ceramic composites at relative low homologous temperatures. In this study, this technique has been used on two powder mixtures—4:1 Ti/B₄C and 1:1 TiC_0.5/TiB₂, which are equivalent in terms of elemental compositions—to produce fully dense titanium carbide-titanium boride composites. The composites formed in each case are comprised of the same final phases—TiC_x, TiB₂, and Ti₃B₄, in roughly the same volume fractions—but exhibit distinctly different grain morphologies. Ti₃B₄ phase nucleates and grows as platelets for the 4:1 Ti/B₄C starting composition but as equiaxed grains for the 1:1 TiC_0.5/TiB₂ composition. TiB has been identified as an intermediate phase in the "platelet" composition and appears to be important to the development of the Ti₃B₄ platelets. X-ray diffractometry and scanning electron microscopy results indicate that the evolution of the microstructure is governed by the diffusion of boron and carbon, rather than titanium. In addition, the faster diffusion of carbon, relative to boron, is instrumental in the microstructural evolution of the platelet composite. The produced composites possess >99% density and good mechanical properties. The higher strength and toughness of the platelet composite are believed to be due to the platelet morphology of the Ti₃B₄ phase.     

Comparative study on the effects of groupware and conventional technologies on the efficiency of collaborative writing

In this paper the concept of efficiency in collaborative writing is considered in detail and a definition of efficiency is proposed. The definition of efficiency leads to the development of a research framework that delineates five operational measures of efficiency: (a) writing activities efficiency, (b) coordination efficiency, (c) quality of output, (d) absence of breakdowns, and (e) satisfaction with group performance. A comparative study is subsequently presented on the effects that groupware and conventional technologies have on the effciency of collaborative writing. The hypothesis is advanced that groupware can improve the efficiency of collaborative writing over conventional technologies. The results seem to support the hypothesis and indicate that (a) the groupware system examined in this study (MUCH system) offers efficiency benefits in terms of coordination, (b) MUCH users tend to face communication breakdowns while users of conventional technologies tend to face task-related breakdowns, (c) the documents produced with MUCH are of higher content quality, more coherent, and of higher rhetorical effectiveness than the documents produced with conventional technologies, and (d) the comparison of MUCH with conventional technologies shows no significant difference in terms of their effects on group performance satisfaction.     

Erosion modelling on reconstructed rough surfaces of wind turbine blades

Numerical simulations of rain droplet impacts on real rough surfaces of leading edges of wind turbine blades are presented. The effect of rough blade surface conditions during liquid impacts on the stress distribution in the protective coating is studied. Realistic rough surfaces of wind turbine blades, obtained from 3D reconstruction of real blades with photogrammetry, as well as artificially generated rough surfaces were introduced into finite element models of the droplet/blade coating interaction. Stress distributions in the protective coating with rough and flat surfaces were studied and compared. The results of the simulations suggest that roughness on the surface of the blade leads to increased stresses in the protective coating.